UNITED STATES GOVERNMENT MEMORANDUM

To: Public Information (MS 5030)

Plans Section, Office of Field 

Operations (MS 5231)

Public Information copy of Exploration Plan

Control # - S-07499

Type - Supplemental Exploration Plan

Lease(s) - OCS-G07957 Block - 762 Mississippi Canyon Area

OCS-G07958 Block - 763 Mississippi Canyon Area

OCS-G07962 Block - 806 Mississippi Canyon Area

OCS-G07963 Block - 807 Mississippi Canyon Area

Operator - Shell Offshore Inc.

Wells A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X

DRILLSHIP

Attached is a copy of the subject plan for public comments on issues that 

should be addressed in an Environmental Assessment.

It has been deemed submitted as of this date and is under review for approval.

Michelle Griffitt

Plan Coordinator

Description -

Rig Type -

Subject:

From:

October 11, 2011
Shell Offshore Inc.

P. O. Box 61933

New Orleans, LA 70161-1933

United States of America

Tel +1 504 728 7215

Fax +1 504 728 6747

Telex http://www.shell.com/eandp-en

Email sylvia.bellone@shell.com

Public Information

August 9, 2011 

Ms. Liz Peuler, Section Chief 

Bureau of Ocean Energy Management, 

Regulation and Enforcement 

1201 Elmwood Park Boulevard 

New Orleans, LA 70123-2394 

 

Attn: Plans Group MS 5231 

SUBJECT: Supplemental Exploration Plan 

 OCS-G 7957, Mississippi Canyon Block 762 

 OCS-G 7958, Mississippi Canyon Block 763 

 OCS-G 7962, Mississippi Canyon Block 806 

 OCS-G 7963, Mississippi Canyon Block 807

 Unit Agreement No. 754393002

 Offshore, Louisiana 

Gentlemen: 

 

In compliance with 30 CFR 250.103 and NTLs 2008-G04, 2009-G27 and 2010-N06, giving Exploration 

Plan guidelines, Shell Offshore Inc (SOI) requests your approval of this Supplemental Exploration Plan 

requesting approval to drill Well Locations A through X. Depending on rig availability operations could 

commence as early as November 1, 2011. 

This Plan consists of a series of attachments describing our intended operations. The attachments we 

desire to be exempted from disclosure under the Freedom of Information Act are marked “Confidential” 

and excluded from the Public Information Copies of this submittal. The cost recovery fee receipt of 

$3,442 ($3,442 for each surface location within 500’) is attached to the Proprietary copy of the Plan. 

The worst case discharge in this plan replaces our Regional Oil Spill Response Plan worst case discharge 

for mobile rig exploration drilling operations. The Revised OSRP and certification were submitted to the 

BOEMRE August 1, 2011 and the certification was deemed submitted August 4, 2011. 

Should you require additional information, please contact me at 504.728.7215 or 

Sylvia.bellone@shell.com. 

Sincerely, 

Sylvia A. Bellone 
SHELL OFFSHORE INC. 

SUPPLEMENTAL EXPLORATION PLAN 

for 

OCS-G 7957, Mississippi Canyon Block 762 

OCS-G 7958, Mississippi Canyon Block 763 

OCS-G 7962, Mississippi Canyon Block 806 

OCS-G 7963, Mississippi Canyon Block 807

Mississippi Canyon Unit No. 754393002 

PUBLIC INFORMATION 

PREPARED BY: 

Sylvia A. Bellone 

 Regulatory Specialist 

504.728.7215 

Sylvia.bellone@shell.com

 
REVISIONS TABLE:

Date & info Request Plan Section What Changed Date of Response 

Info request 8/24/11 Plan Info Forms & Section 

2E 

9 – Oil Spill Information 

Removed New 

Technology 

Added certification 

statement 

8/26/11 

8/26/11 

 

 

 
Supplemental Exploration Plan 

OCS-G 7957, Mississippi Canyon Block 762 

OCS-G 7958, Mississippi Canyon Block 763 

OCS-G 7962, Mississippi Canyon Block 806 

OCS-G 7963, Mississippi Canyon Block 807

Mississippi Canyon Unit No. 754393002 

Table of Contents

1. Plan Contents 

2. General Information 

3. Geological and Geophysical 

4. H2S 

5. Mineral Resource Conservation 

6. Biological, Physical and Socioeconomic 

 Information 

7. Waste and Discharge Information 

8. Air Emission Information 

9. Oil Spill Information 

10. Environmental Monitoring 

11. Lease Stipulations 

12. Environmental Mitigation Measures 

13. Related Facilities and Operations Information 

14. Support Vessels and Aircraft 

15. Onshore Support Facilities Information 

16. Sulphur Operations 

17. Coastal Zone Management Act Information 

18. Environmental Impact Analysis 

19. Administrative Information 

 

 

 

 

 
SECTION 1: PLAN CONTENT

A. DESCRIPTION, OBJECTIVES & SCHEDULE

This Supplemental Exploration Plan (SEP) with appendices, including an Environmental Impact Analysis (EIA) 

found in Section 18, describes the drilling activities Shell Offshore Inc. (Shell) plans to conduct with respect to 

leases OCS-G 7957, 7958, 7962 & 7963, Mississippi Canyon Blocks 762, 763, 806 & 807. This Plan is for the 

batch-set drilling of 24 wells (A through X). Shell’s plan, as detailed in this SEP, is to use a Drill Ship, the M/V 

Bully 1 or equivalent rig (the “Rig”), to drill up to four (24) new exploration wells (A-X) in the Mississippi Canyon 

Block 807 in preparation for the installation of a TLP at a later date. The wells will be drilled and temporarily 

abandoned (cement plug and corrosion cap) until the wells are deepened, completed and developed under a 

future plan. If a well is unsuccessful, it will be permanently plugged and abandoned in accordance with BOEM 

regulations. The timeframe to complete the initial drilling activities is an estimate based on the best available 

information regarding downhole conditions likely to be encountered while drilling each well and not intended to be 

a limitation. 

The Rig is a Drill Ship and is equipped with state-of-the-art drilling and well control equipment. It is a largely selfcontained drilling vessel, with accommodations for a crew, including quarters, galley and sanitation facilities. The 

Rig will comply with the requirements in the Interim Final Rules. The drilling activities will be supported by the 

support vessels and aircraft as well as onshore support facilities as listed in Sections 14 and 15 of the SEP. Shell 

has employed or contracted with trained personnel to carry out its exploration activities. Shell is committed to 

local hire, local contracting and local purchasing to the maximum extent possible. Shell personnel and contractors 

are experienced at operating in the Gulf of Mexico and are well versed in all Federal and State laws regulating 

operations. Shell’s employees and contractors share Shell’s deep commitment to operating in a safe and 

environmentally responsible manner. 

Shell, through its parent and affiliate corporations, has extensive experience safely exploring for oil and gas in the 

Gulf of Mexico. Shell will draw upon this experience in organizing and carrying out its planned MC drilling 

program. Shell believes that the best way to manage blowouts is to prevent them from happening. Significant 

effort goes into the design and execution of wells and into building and maintaining staff competence. In the 

unlikely event of a spill, Shell’s Regional OSRP (July 1, 2011) is designed to contain and respond to a spill that 

meets or exceeds the WCD detailed in Section 9 of this SEP. The WCD does not take into account potential flow 

mitigating factors such as well bridging, obstructions in wellbore, reservoir barriers, or early intervention. 

continue to invest in Research and Development (R&D) to improve safety and reliability of our well systems. All 

operations will be conducted in accordance with applicable federal and state laws, regulations, and lease and 

permit requirements. Shell will have trained personnel and monitoring programs in place to ensure such 

compliance. 

B. LOCATION

See attached BOEM plan information forms and location plats. 

C. RIG SAFETY AND POLLUTION FEATURES: 

The Rig we plan to use (Bully 1 or similar) will comply with all of the regulations of the American Bureau of 

Shipping (ABS), International Maritime Organization (IMO) and the United States Coast Guard (USCG). All drilling 

operations will be conducted under the provisions of 30 CFR, Part 250, Subpart D, and other applicable 

regulations and notices, including those regarding the avoidance of potential drilling hazards and safety and 

pollution prevention control. Such measures as inflow detection and well control, monitoring for loss of circulation 

and seepage loss, and casing design will be our primary safety measures. Primary pollution prevention measures 

are contaminated and non-contaminated drain systemand oily water processing. 

DRAIN SYSTEM POLLUTION FEATURES 

Drains are provided on the Rig in all spaces and on all decks where water or oil can accumulate. The drains are 

divided into two categories, non-contaminated and contaminated. All deck drains are fitted with a removable 

strainer plate to prevent debris entering the system. 

Deck Drainage from rainfall, Rig washing, deck washing, and runoff from curbs and gutters, including drip pans 

and work areas, are discharged depending on if it comes in contact with the contaminated or non-contaminated 

areas of the Rig. 
1) Non-contaminated Drains 

Non-contaminated drains are designated as drains that under normal circumstances do not contain 

hydrocarbons, and can be discharged directly overboard. These are mostly located around the main deck and 

outboard in places where it is unlikely that hydrocarbons will be found. 

Drains within 50 feet of a designated chemical storage area which uses the weather deck as a primary 

containment means shall be designated “normally plugged.” An adequate number of drains around the rig 

shall be designated as “normally open” to allow run-off of rain water. Normally open drains shall have a plug 

located in a conspicuous area near the drain which can be easily installed in the event of a spill. 

The rig’s drain plug program consist at a minimum of a weekly check of all deck drains leading to the sea to 

verify that their status is as designated If normally open they shall verify that the drain is open and that the 

plug is available in the area. If normally closed they shall verify that the plug is securely installed in the drain. 

In the event a leak or spill is observed, the event shall be contained (drain plug installation and / or spill kit 

deployment as appropriate) and reported immediately. 

Rig personnel shall ensure that the perimeter kick-plates on weather decks are maintained and drain plugs are 

in place as needed to ensure a proper seal. 

2) Contaminated Drains 

Contaminated drains are designated as drains that contain hydrocarbons and cannot be discharged overboard. 

When oil-based mud is used for drilling it will be collected in portable tanks and sent to shore for processing. 

3) Oily Water Processing 

Oily water is collected in an oily water tank. It must be separated and not pumped overboard until oil 

content is < 15 ppm. The separated oil is pumped to a dirty oil tank and has to be sent ashore for disposal. 

On board the MODU an oil record log has to be kept according to instructions included in the log. Any and all 

pollution pans are subjected to a sheen test before being pumped out. If the water passes the sheen test 

then it is pumped over board. If it does not pass the sheen test then the water/oil mixture is pumped to a 

dirty oil tank and sent to shore for disposal. All waste oil that is sent in to be disposed of is recorded in the 

MODU’s oil log book. 

All discharges will be in accordance with applicable NPDES permits. See Attachment 18, EIA of this Plan. 

 
4) Lower Hull Bilge System 

• The main bilge system is designed to drain the pontoons. There are Gould’s electrically driven, self priming 

centrifugal pumps - one for each main pump room. The aux pumps can be pump out with the bilge pump 

but has to be lined up manually from the main pump room. 

• Bilge water is pumped overboard after a sheen test has been completed. 

• The pontoon bilge pumps are operable from the Bridge, and have audible and visual bilge alarms set for 

high and low levels. 

• Portable submersible pumps are carried onboard the rig to service all column void spaces and are also used 

for emergency bilge pump in the event of the main pump room flooding. 

• Alternate means of pumping the bilges in each pontoon pump room include the use of: 

• The ballast system emergency bilge valve which is operated from the control panel. 

• Portable submersible pumps 

• Emergency bilge suction line connected directly to the ballast manifold. (Main Pump rooms only) 

The Bilge pumps are manual/automatic type pumps. They are equipped with sensors that give a high and a 

high-high alarm. They are set to a point at which the water gets to a certain point they will automatically turn 

on to pump water out in order to keep flooding under control. The pumps are also capable of being put in 

manual mode in which they can be turned on by hand. 

5) Emergency Bilge System 

Main ballast pumps may also be used for emergency bilge pumping directly from the pump rooms via remotely 

actuated direct bilge suction valves on the ballast system. These valves will operate in a fully flooded 

compartment. The ballast pumps can be supplied from the emergency switchboard. 

6) Oily Water Drain/Separation System

Oily water/engine room bilge water is collected in an oily water tank. It must be separated and not pumped 

overboard until oil content is < 15 ppm. The separated oil is pumped to a dirty oil tank and has to be sent 

ashore for disposal. On board all drilling Units, an oil record log has to be kept according to instructions 

included in the log. The rig floor has two skimmer tanks and each is subjected to a sheen test before pumping 

overboard to ensure environmental safety. All three anchor winch windlasses have skimmer tanks and are 

subjected to sheen tests before discharge as well 

7) Drain, Effluent and Waste Systems 

• The Rig’s drainage system is designed in line with our environmental and single point discharge policies. 

Drains are either hazardous, i.e. from a hazardous area as depicted on the Area Classification drawings, 

or non-hazardous drains from nonhazardous areas. 

• To prevent migration of hazardous materials and flammable gas from hazardous to non-hazardous areas, 

the drainage systems are segregated. 

• The Rig drainage systems tie into oily water separators that take out elements in the drainage that could 

harm the environment. This is part of Noble’s initiative to be good stewards of the environment. The oily 

water separators divide the drainage system into these sections: 

8) Rig Floor Drainage 

The Rig floor has been outfitted with a Facet International MAS 34-3 separator. The separator has coalescent 

plates that remove the solids from the drainage, and the remaining drainage goes to a skimmer tank. From the 

skimmer tank it is drained to one of the column dirty oil tank systems where it is then sent through 2 

separators and cleaned further to reduce oil content to less than 15 ppm. 

 
9) Columns #3 & 4 

The drains on the decks and machinery spaces are separated at mid ship and directed to either the #3 or #4 

columns. The separators in these columns go through three cycles of circulation and remove oil to less than 

15ppm, then discharge the clean product to sea. 

10) Main Engine Rooms 

• The engine rooms have their own drainage and handling system. The engine rooms are outfitted with a 

dirty oil tank and the drainage in the tank is processed through the separator, the waste from the 

separator goes back to the dirty oil tank and the clean water (less than 15ppm) goes overboard. 

• The locations and models of the separators are as follows: 

• Column #3 – Westfalia WSD-18 

• Column #4 – Westfalia WSD-18 

• Drill Floor – Facet International MAS 34-3 

11) Helideck Drains 

The helideck has a dedicated drainage system around its perimeter to drain heli-fuel from a helicopter incident. 

The fuel can be diverted to the designated heli-fuel recovery tank which is located under the Helideck structure. 

Operating configurations are as follows: 

3⁄4 The overboard piping valves and hydrocarbons take on valves are closed and locked. To unlock 

overboard or take on valves a permit has to be filled out. 

3⁄4 The oily water collection tank overflow valve is closed. 

3⁄4 The drill floor drains are lined-up to the drill floor skimmer tank. The Skimmer tanks have a high alarm 

which sounds by means of an air horn. Before tanks are pumped out a sheen test is performed. Water 

is pump out the skimmer tanks down the shunt line. Oil containment side is pumped out into 550 gal 

tote tanks. 

3⁄4 The BOP test area drains are normally lined-up to drain overboard. 

3⁄4 The oily water separator continuously circulates the oily water collection tank. Waste oil is discharged 

into the waste oil tank and oily water is re-circulated back into the oily water collection tank. Clean 

water is pumped overboard, which is controlled and monitored by the oil content detector, set at 15 

ppm. 

3⁄4 The solids control system is capable of being isolated for cuttings collection. 

3⁄4 The bilge system is normally pumped directly overboard after a sheen test has been performed. 

3⁄4 The engine dirty oil sump can be drained down in Port column oily water separator which discharges 

water overboard from the water side and oil being pumped out into a 550 gal tote tank oil containment 

side. There is a high audible alarm on the ballast control panel. 

D. Storage Tanks - Bully 1 

Type of 

Storage 

Tank 

Type 

of 

Facility 

Tank 

Capacity 

(bbls) 

Number 

of 

Tanks 

Total 

Capacity 

(bbls) 

Fluid 

Gravity 

(API) 

Fuel oil MODU 2652 1 2652 No. 2 

diesel 

Fuel oil MODU 1,743 1 1743 No. 2 

diesel 

Fuel oil MODU 5767 1 5767 No. 2 

diesel 

 
Fuel oil MODU 4399 1 4399 No. 2 

diesel 

Fuel oil MODU 2652 1 2652 No. 2 

diesel 

Fuel oil MODU 3250 1 3250 No. 2 

diesel 

Fuel oil MODU 4399 1 4399 No. 2 

diesel 

Fuel oil MODU 2618 1 2618 No. 2 

diesel 

Fuel oil MODU 115 4 460 No. 2 

diesel 

Fuel oil MODU 129 4 516 No. 2 

diesel 

E. Pollution Prevention Measures 

Pursuant to NTL 2008-G04 the proposed operations covered by this SEP do not require Shell to specifically 

address the discharges of oils and greases from the Rig during rainfall or routine operations. Nevertheless, 

Shell has provided this information as part of its response to in 1(c) above. 

F. Additional Measures

 

3⁄4 HSE (health safety and environment) are the primary topics in pre-tour and pre-job safety meetings. The 

discussion around no harm to people or environment is a key mindset. All personnel are reminded daily 

to inspect work areas for safety issues as well as potential pollution issues. 

3⁄4 All tools that come to and from the Rig have their pollution pans inspected, cleaned and confirmation of 

plugs installed prior to leaving dock and prior to loading on the boat. 

3⁄4 Preventive Maintenance of Rig equipment includes visual inspection of hydraulic lines and reservoirs on 

routine scheduled basis. 

3⁄4 All pollution pans on Rig are inspected daily. 

3⁄4 Containment dikes are installed around all oil containment, drum storage areas, fuel vents, fuel storage 

tanks. 

3⁄4 All used oil and fuel is collected and sent in for recycling. 

3⁄4 Every drain on the Rig is assigned a number on a checklist. The checklist is used daily to verify drain 

plugs are installed. 

3⁄4 All trash containers are checked and emptied daily. The trash containers are kept covered. Trash is 

disposed of in a compactor and shipped in via boat. 

3⁄4 The Rig is involved in a recycling program for cardboard, plastic, paper, glass, and aluminum. 

3⁄4 Fuel hoses and SBM are changed on annual basis. 

3⁄4 TODO spill prevention fittings are installed on all liquid take on hoses. 

3⁄4 Waste paint thinner is recycled on board with a solvent still to reduce hazard of shipping and storage. 

3⁄4 All equipment on board utilizes Envirorite hydraulic fluid as opposed to hydraulic oil. Shell has obtained 

ISO14001 certification. 

 
U. S. Department of the Interior OMB Control Number: 1010-0151 

Minerals Management Service OMB Approval Expires: December 31, 2011 

OCS PLAN INFORMATION FORM 

General Information

Type of OCS Plan: X Exploration Plan (EP) Development Operations Coordination Document (DOCD) 

Company Name: Shell Offshore Inc MMS Operator Number: 0689 

Address: P. O. Box 61933 Contact Person: Sylvia Bellone 

 New Orleans, LA 70161-1933 Phone Number: (504) 728-7215 

 E-Mail Address: sylvia.bellone@shell.com 

Lease(s): OCS-G 07957, 7958, 7962 & 

7963 

Area: MC Block(s): 762, 762, 806 

& 807 

Project Name (If Applicable): Olympus 

Objective(s): X Oil Gas Sulphur Salt Onshore Base: Fouchon 

& Boothville 

Distance to Closest Land (Miles): 53 

Description of Proposed Activities (Mark all that apply)

X Exploration drilling Development drilling 

Well completion Installation of production platform 

Well test flaring (for more than 48 hours) Installation of production facilities 

Installation of caisson or platform as well protection structure Installation of satellite structure 

Installation of subsea wellheads and/or manifolds Commence production 

Installation of lease term pipelines Other (Specify and describe) 

Have you submitted or do you plan to submit a Conservation Information Document to accompany this plan? Yes X No 

Do you propose to use new or unusual technology to conduct your activities? Yes X No 

Do you propose any facility that will serve as a host facility for deepwater subsea development? Yes X No 

Do you propose any activities that may disturb an MMS-designated high-probability archaeological area? X Yes No 

Have all of the surface locations of your proposed activities been previously reviewed and approved by MMS? Yes X No 

Tentative Schedule of Proposed Activities

Proposed Activity Start 

Date 

End 

Date 

No. of Days 

See attached schedule 

 

Description of Drilling Rig Description of Production Platform

 Jackup X Drillship Caisson Tension leg platform

 Gorilla Jackup Platform rig Well protector Compliant tower 

Semisubmersible Submersible Fixed platform Guyed tower

 DP Semisubmersible Other (Attach 

Description) 

 Subsea manifold Floating production system 

Drilling Rig Name (If Known): Bully 1 or similar Spar Other (Attach Description) 

Description of Lease Term Pipelines

From (Facility/Area/Block) To (Facility/Area/Block) Diameter 

(Inches) 

Length (Feet) 

N/A 

 

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) 

 
Proposed

Activity Start Date End Date No. of Days

Batch Set A 11/01/2011 11/16/2011 15

Batch Set B 11/16/2011 11/26/2011 10

Batch Set C 11/26/2011 12/11/2011 15

Batch Set D 12/11/2011 12/21/2011 10

Batch Set E 12/21/2011 12/31/2011 10

Batch Set  F 12/31/2011 01/15/2012 15

Batch Set G 01/15/2012 01/30/2012 15

Batch Set H 01/30/2012 02/09/2012 10

Batch Set  I 02/09/2012 02/19/2012 10

Batch Set J 02/19/2012 02/29/2012 10

Batch Set K 02/29/2012 03/10/2012 10

Batch Set L 03/10/2012 03/20/2012 10

Batch Set M 03/20/2012 04/04/2012 15

Batch Set N 04/04/2012 04/14/2012 10

Batch Set O 04/14/2012 04/24/2012 10

Batch Set P 04/24/2012 05/09/2012 15

Batch Set Q 05/09/2012 05/19/2012 10

Batch Set R 05/19/2012 05/29/2012 10

Batch Set S 05/29/2012 06/08/2012 10

Batch Set T 06/08/2012 06/18/2012 10

Batch Set U 06/18/2012 06/28/2012 10

Batch Set V 06/28/2012 07/08/2012 10

Batch Set W 07/08/2012 07/18/2012 10

Batch Set X 07/18/2012 07/28/2012 10

Drill to TD MB01 (A)   07/28/2012 02/27/2013 214
 

OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well A Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7030 FNL 

E/W Departure: 285 FWL 

Lambert X-Y 

coordinates 

X: 919,005

Y: 10,225,610

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.656" 

Longitude 

W 89° 14' 21.605" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

3gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate 

or any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) 

 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well B Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7043 FNL 

E/W Departure: 319 FWL 

Lambert X-Y 

coordinates 

X: 919,039

Y: 10,225,597

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.533" 

Longitude 

W 89° 14' 21.227" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well C Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,007 FNL 

E/W Departure: 318 FWL 

Lambert X-Y 

coordinates 

X: 919,038

Y: 10,225,633

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.890" 

Longitude 

W 89° 14' 21.244" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)

 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well D Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,027 FNL 

E/W Departure: 332 FWL 

Lambert X-Y 

coordinates 

X: 919,052

 Y: 10,225,613 

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.689" 

Longitude 

W 89° 14' 21.079" 

TVD (Feet): 

-

MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well E Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,050 FNL 

E/W Departure: 300 FWL 

Lambert X-Y 

coordinates 

X: 919,020

Y: 10,225,590

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.456" 

Longitude 

W 89° 14' 21.441" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)

 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well F Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,027 FNL 

E/W Departure: 307 FWL 

Lambert X-Y 

coordinates 

X: 919,027

Y: 10,225,613

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.693" 

 Longitude 

W 89° 14' 21.359" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)

 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well G Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,012 FNL 

E/W Departure: 346 FWL 

Lambert X-Y 

coordinates 

X: 919,066

Y: 10,225,628

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.846" 

Longitude 

W 89° 14' 20.932" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well H Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 6,992 FNL 

E/W Departure: 357 FWL 

Lambert X-Y 

coordinates 

X: 919,077

Y: 10,225,648

Latitude/ 

Longitude

Latitude 

N 28° 09' 36.043" 

Longitude 

W 89° 14' 20.817" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well I Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 6,989 FNL 

E/W Departure: 379 FWL 

Lambert X-Y 

coordinates 

X: 919,099

Y: 10,225,651

Latitude/ 

Longitude

Latitude 

N 28° 09' 36.079" 

Longitude 

W 89° 14' 20.570" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)

 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well J Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,032 FNL 

E/W Departure: 360 FWL 

Lambert X-Y 

coordinates 

X: 919,080

Y: 10,225,608

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.646" 

Longitude 

W 89° 14' 20.767" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) 

 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well K Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,009 FNL 

E/W Departure: 393 FWL 

Lambert X-Y 

coordinates 

X: 919,113

Y: 10,225,631

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.879" 

Longitude 

W 89° 14' 20.406" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) 

 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well L Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,013 FNL 

E/W Departure: 371 FWL 

Lambert X-Y 

coordinates 

X: 919,091

Y: 10,225,627

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.843" 

Longitude 

W 89° 14' 20.652" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) 

 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well M Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,087 FNL 

E/W Departure: 325 FWL 

Lambert X-Y 

coordinates 

X: 919,045

Y: 10,225,553

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.096" 

Longitude 

W 89° 14' 21.145" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) 
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well N Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,080 FNL 

E/W Departure: 345 FWL 

Lambert X-Y 

coordinates 

X: 919,065

Y: 10,225,560

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.173" 

Longitude 

W 89° 14' 20.931" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well O Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,064 FNL 

E/W Departure: 358 FWL 

Lambert X-Y 

coordinates 

X: 919,078

Y: 10,225,576

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.329" 

Longitude 

W 89° 14' 20.783" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well P Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,067 FNL 

E/W Departure: 311 FWL 

Lambert X-Y 

coordinates 

X: 919,031

Y: 10,225,573

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.296" 

Longitude 

W 89° 14' 21.309" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well Q Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,044 FNL 

E/W Departure: 344 FWL 

Lambert X-Y 

coordinates 

X: 919,064

Y: 10,225,596

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.529" 

Longitude 

W 89° 14' 20.948" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well R Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,063 FNL 

E/W Departure: 333 FWL 

Lambert X-Y 

coordinates 

X: 919,053

Y: 10,225,577

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.333" 

Longitude 

W 89° 14' 21.063" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well S Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,049 FNL 

E/W Departure: 372 FWL 

Lambert X-Y 

coordinates 

X: 919,092

Y: 10,225,591

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.486" 

Longitude 

W 89° 14' 20.636" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well T Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,029 FNL 

E/W Departure: 382 FWL 

Lambert X-Y 

coordinates 

X: 919,102

Y: 10,225,611

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.682" 

Longitude 

W 89° 14' 20.521" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well U Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,026 FNL 

E/W Departure: 404 FWL 

Lambert X-Y 

coordinates 

X: 919,124

Y: 10,225,614

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.719" 

Longitude 

W 89° 14' 20.275" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well V Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,069 FNL 

E/W Departure: 386 FWL 

Lambert X-Y 

coordinates 

X: 919,106

Y: 10,225,571

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.286" 

Longitude 

W 89° 14' 20.471" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well W Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7,046 FNL 

E/W Departure: 419 FWL 

Lambert X-Y 

coordinates 

X: 919,139

Y: 10,225,594

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.519" 

Longitude 

W 89° 14' 20.110" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)
OCS PLAN INFORMATION FORM (CONTINUED) 

Include one copy of this page for each proposed well/structure 

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Well X Subsea Completion 

Anchor Radius (if applicable) in feet: NA X Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07963 

Area Name Mississippi Canyon 

Block No. 807 

Blockline 

Departures 

(in feet)

N/S Departure: 7049 FNL 

E/W Departure: 397 FWL 

Lambert X-Y 

coordinates 

X: 919,117

Y: 10,225,591

Latitude/ 

Longitude

Latitude 

N 28° 09' 35.482" 

Longitude 

W 89° 14' 20.357" 

TVD (Feet): MD (Feet): Water Depth (Feet): 3030 

Anchor Locations for Drilling Rig or Construction Barge (If anchor radius supplied above, not necessary) 

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

 X = Y = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.196. An agency 

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a 

currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public reporting 

burden for this form is included in the burden for preparing Exploration Plans and Development Operations Coordination 

Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, 

gathering and maintaining data, and completing and reviewing the form. Direct comments regarding the burden estimate or 

any other aspect of this form to the Information Collection Clearance Officer, Mail Stop 4230, Minerals Management 

Service, 1849 C Street, N.W., Washington, DC 20240.

MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.)

 
3100

3050

3250

3250

3150

3150

3200

3200

3200

3100

3050

3000

3000

2950

SHELL ET AL

BLK. 806

OCS-G07962

SHELL ET AL

BLK. 807

OCS-G07963

SHELL ET AL

BLK. 762

OCS-G07957

SHELL ET AL

BLK. 763

OCS-G07958

X=918,720

Y=10,232,640

Mississippi Canyon Block 807

OCS-G07963

Proposed MB-1 Well Location

with Bathymetry 3

...\CAD_NewOrleans\Maps\Permit Plats\Mars B\Mars B Proposed Well MB-1 with Bathymetry.mxd

NAD_1927_UTM_Zone_16N

Projection: Transverse_Mercator

False_Easting: 1640416.666667

False_Northing: 0.000000

Central_Meridian: -87.000000

Scale_Factor: 0.999600

Latitude_Of_Origin: 0.000000

Linear Unit: Foot_US

0 500 1,000 2,000 3,000 4,000

Feet

Shell Exploration and Production Co.

Prop. MB-1 Surface Loc.:

X= 919,005.00'

Y=10,225,610.00'

7030.00' FNL and 285.00' FWL of Blk 807
")

")

")

")

")

")

")

")

")

")

")

")

")

")

") ")

")

")

")

")

")

")

")

") X

W

V

U

T

S

R

Q

P

O

N

M

L

K

J

I

H

G

F

E

D

C

B

A

Mississippi Canyon Block 807

OCS-G07963

Proposed Surface Locations

of all Olympus Wells

3

...\CAD_NewOrleans\Maps\Permit Plats\Mars B\Mars B Proposed Surface Locations.mxd

Shell Exploration and Production Co.

7080'

7100

7120'

7060'

7040'

7020'

7000'

6980'

6960'

280' 300' 320' 340' 360' 380' 400' 420'

Distance from West Line of MC 807

Distance from North Line of MC 807

0 10 20 40 60

Feet

MB-1

MB-2

MB-3

MB-4

MB-5

MB-6

MB-7

MB-8

MB-9

MB-10

MB-11

MB-12

MB-13

MB-14

MB-15

MB-16

MB-17

MB-18

MB-19

MB-20

MB-21

MB-22

MB-23

MB-24

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

X=919,005'

X=919,039'

X=919,038'

X=919,052'

X=919,020'

X=919,027'

X=919,066'

X=919,077'

X=919,099'

X=919,080'

X=919,113'

X=919,091'

X=919,045'

X=919,065'

X=919,078'

X=919,031'

X=919,064'

X=919,053'

X=919,092'

X=919,102'

X=919,124'

X=919,106'

X=919,139'

X=919,117'

Y=10,225,610'

Y=10,225,597'

Y=10,225,633'

Y=10,225,613'

Y=10,225,590'

Y=10,225,613'

Y=10,225,628'

Y=10,225,648'

Y=10,225,651'

Y=10,225,608'

Y=10,225,631'

Y=10,225,627'

Y=10,225,553'

Y=10,225,560'

Y=10,225,576'

Y=10,225,573'

Y=10,225,596'

Y=10,225,577'

Y=10,225,591'

Y=10,225,611'

Y=10,225,614'

Y=10,225,571'

Y=10,225,594'

Y=10,225,591'

Original Mars B/

Olympus Well Name BOEM Name x/y coordinates (UTM 316)
SECTION 2: GENERAL INFORMATION

A. Application and Permits

There are no individual or site-specific permits other than general NPDES Permit and rig move notification that 

need to be obtained. 

B. Drilling Fluids 

See Table 7A for a list of drilling fluids to be used. 

C. Production

Information regarding production is not included in this SEP as such information is only necessary in the case of 

DOCDs. 

D. Oil Characteristics

Information regarding Oil Characteristics is not included in this SEP as such information is only necessary in the 

case of DOCDs. 

E. New Or Unusual Technology

No new technology proposed as part of this work. 

F. Bonding

The bond requirement for the activities proposed in this SEP are satisfied by an area-wide bond furnished and 

maintained according to 30 CFR Part 256, Subpart I-Bonding; NTL No. 2000-G16, “Guideline for General Lease 

Surety Bonds” and National NTL No. 2008-N07, “Supplemental Bond Procedures.” 

G. Oil Spill Financial Responsibility (OSFR)

Shell Offshore Inc (SOI), BOEM Operator Number 0689, has demonstrated oil spill financial responsibility for the 

facilities proposed in the EP according to 30 CFR Parts 250 and 253, and NTL No. 2008-N05, “Guidelines for Oil 

Spill Financial Responsibility for Covered Facilities.” 

H. Deepwater well control statement

Shell Offshore Inc (SOI), BOEM Operator Number 0689, has the financial capability to drill a relief well and 

conduct other emergency well control operations. 

I. Suspension of Production

Information regarding Suspension of Production is not included in this EP as such information is only necessary 

in the case of DOCDs. 
penetration is relatively close to the W3.0 Gold reservoir’s oil water contact, and under WCD flow, it is expected to 

produce water within the first 30 days; thus reducing the 30-day average WCD volume. Shell’s Regional OSRP has 

response capabilities based on the first 30-day average daily rate; thus in the unlikely event of a spill, Shell’s Regional 

OSRP is designed to contain and respond to a spill that meets or exceeds this WCD. 

The WCD scenario, in terms of both initial and the sustained rates, has a low probability of being realized. Some of the 

factors that are likely to reduce rates and volumes, and are not included in the WCD calculation, include but are not 

limited to, obstructions or equipment in the wellbore, well bridging, and early intervention, such as containment 

capabilities. 

Uncontrolled blowout (volume first day) 465,000 bbls 

Uncontrolled blowout rate (first 30-days average daily rate) 365,000 bbls 

Duration of flow (days) based on relief well 182 days 

Total volume of spill (bbls) for 182 days 25.2MMBO 

Table 1 Worst Case Discharge Summary 

The Olympus Tension Leg Platform (TLP) will be located in the Mars Ursa Basin and represents an additional and 

continued development of the Mars Field. The Olympus TLP includes the installation of 24 well slots. The Exploration 

Plan which accompanies this 2010-NTL-06 document covers drilling all of the proposed 24 well paths. Based on the 

proposed well paths, open-hole intervals, and targets, the 24 well paths were assessed for their WCD potential. The 

through-salt Deimos W3.0 Gold well (MB-1) was determined to be the Olympus well with the highest individual WCD 

potential. 

The proposed Olympus TLP will be the second TLP in the Mars Field and is located approximately 46 miles eastsoutheast of the nearest shoreline in the Gulf of Mexico (GOM), in water depths of approximately 3,030 feet (ft). 

The history of the Mars Field began with the acquisition of the exploration leases between 1985 and 1988. The 

discovery well (MC-763 #1) and its appraisal by-passes were drilled in 1989. The discovery well was followed by 

appraisal wells (MC-807 #1, #2, #3, #4, and #5, and MC-806 #1), and associated by-passes and sidetracks between 

1989 and 1991. The Mars A TLP was installed and brought onto production in 1996. The Mars field encompasses six 

OCS Leases in the Mississippi Canyon Area – Blocks 762, 763, 806, 807, 850 and 851; that are captured within the 

Mars Operating Unit. 

The Deimos Field is essentially ‘deep Mars’, with reservoirs located below the deepest Mars production (Terra 

Cotta) in a sub-salt environment. The Deimos discovery well was drilled in 2002, with the Phase I development 

(three well subsea tie-back to the Mars A TLP) coming on production in July 2007. 

The Mars Field (including Deimos) is comprised of a thick sequence of stacked Plio-Miocene turbidite deposits trapped 

within the salt-flanked Mars-Ursa mini-basin. The Mars Field comprises of more than 70 individual reservoirs stacked 

in a 10,000 foot sequence. These reservoirs include: 

• Sub-salt reservoirs added to the field with the 2002 Deimos discovery. 

• Six large-scale, laterally extensive and well connected reservoirs in the above-salt section which 

form the targets for the current Mars A waterflood activity. 

• A large number of generally shallower and smaller-scale depletion drive reservoirs. 

The MB-1 well targets the W3.0 Gold reservoir. The W3.0 Gold is the principal component of the Gold reservoir, 

occurring at tvdss depths typically ranging from 20,200ft to 20,600ft within the deep reservoir fault block. It comprises 

a widespread, large-scale, high net-to-gross, amalgamated sand body, ranging from ~150ft to 250ft in true vertical 

thickness. The structural interpretation of the W3.0 Gold, together with the OWC observed at 20,442ft (tvdss) indicate 

that recoverable volumes are largely restricted to the up-dip crestal portion of the deep reservoir fault block structure. 

The MB-1 well will target the up-dip or crestal area of the deep reservoir fault block. In more down-dip areas of the 

field, the W3.0 Gold is interpreted to be laterally extensive, wet, more heterogeneous and displays systematic upwardfining grain size trend. The W3.0 Gold reservoir is expected to include a large aquifer. 

Detailed reservoir models have been constructed for all of the main Mars and Deimos reservoir horizons. The static 

reservoir models have been constructed using the full suite of subsurface data collected during the evaluation of these 

Mars and Deimos wells, and these have subsequently been converted to dynamic simulation models for history 

matching and development planning and forecasting. 
Shell’s seismic interpretation used for constructing the Deimos W3.0 Gold reservoir model is based on high quality 

anisotropic ocean bottom nodes - wide azimuth (OBS WAZ) seismic survey. A seismic profile through the proposed 

MB-1 well target is included in the attachment. This survey has an excellent well tie to the relevant offset well 

penetrations, thus giving a high confidence interpretation. The seismic interpretation was used for constructing the 

structure and stratigraphic framework of the model. Due to the excellent seismic to well ties, the amplitude 

extraction maps were correlated to the reservoir characteristics of each well and extrapolated across the entire area of 

the W3.0 Gold sand in the basin. These seismic extraction maps were then imported into Petrel for construction of 

the deterministic W3.0 Gold static reservoir model. The static model was then used to construct a MBAL/Propser 

model for reservoir simulation. The MB-1 well target was simulated in this MBAL/Prosper model. Therefore the 

resulting WCD calculation included in this document is based on the reservoir properties indicated from the reservoir 

model at the target location. This document is a summary of the results of this modelling. Electronic copies of the 

reservoir model and its output can be provided to the BOEMRE upon request. 

For the Deimos W3.0 Gold WCD scenario, the model considered the maximum reservoir drainage area with no internal 

fault sealing or baffling incorporated and the aquifer extent modelled as per the expectation extent and magnitude. 

Purpose 

Pursuant with 30 CFR 250.213(g), 250.219, 250.250, and NTL No. 2010-N06, this document provides a blowout 

scenario description, further information regarding any potential oil spill, the assumptions and calculations used to 

determine the WCD and the measures taken to 1) enhance the ability to prevent a blowout and 2) respond and 

manage a blowout scenario if it were to occur. These calculations are based on best technical estimates of subsurface 

parameters that are derived from the offset wells, and seismic. These parameters are better than or consistent with 

the estimates used by Shell to justify the investment. Therefore, these assumed parameters were used to calculate the 

WCD. They do not reflect probabilistic estimates. 

2) Background 

This attachment has been developed to document the additional information requirements for Exploration Plans as 

requested by NTL No. 2010-N06 in response to the explosion and sinking of the Mobile Offshore Drilling Unit (MODU) 

Deepwater Horizon and the resulting subsea well blowout and recovery operations of the exploration well at the MC252 Macondo location. 

3) Information Requirements 

a) Blowout scenario 

All locations of the proposed Olympus EP supplement were assessed for Worst Case Discharge. The MB-1 

(well location A) well represented the highest 30-day average flow potential. The MB-1 well was drilled to the 

W3.0 Gold Sand as outlined in the Geological and Geophysical Information Section of the Supplemental EP, 

and described above, utilizing a typical subsea wellhead system, conductor, surface and intermediate casing 

program, and using a MODU rig with a marine riser and subsea Blowout Preventer. A hydrocarbon influx and 

a well control event are modeled to occur from the W3.0 Gold Sand during a trip out of the hole. The 

simulated blowout model results in unrestricted flow from the well at the seafloor which represents the worst 

case discharge, no restrictions in the wellbore, failure/loss of the subsea BOP, and a blowout to the seabed. 

 
b) Estimated flow rate of the potential blowout 

Category EP 

Type of Activity Drilling 

Facility Location (area/block) MC-807 

Facility Designation MODU 

Distance to Nearest Shoreline (miles) 46 Statute miles 

Uncontrolled blowout (volume first day) 465,000 bbls 

Uncontrolled blowout rate (first 30-days average daily rate) 365,000 bbls 

Table 2 Estimated Flow Rates of a Potential Blowout 

c) Total volume and maximum duration of the potential blowout 

Duration of flow (days) 182 days total duration to drill relief well 

(including 14 days to mobilize rig) 

Total volume of spill (bbls) 25.2 MMBO 

Note: based on MBAL/Prosper Model 

Table 3 Estimated Duration and Volume of a Potential Blowout 

There is usually a decline in the discharge rate as time proceeds, which is illustrated by the differences 

between the first 24-hour volume and 30-day average rate. The total volume calculated until a well is killed in 

a potential blowout further demonstrates this decline. At very short times, e.g. during the first 24 hours, the 

pressure profile in the reservoir changes from the moment when a well first starts flowing to a pseudo-steady 

state pressure profile with time, and as a result the rate declines. At somewhat longer time scales, effects such 

as reservoir voidage and the impact of boundaries can cause the rate to drop continuously with production. 

Simulation and material balance models can include these effects and form the basis of the NTL No. 2010-N06 

estimates for 24-hour and 30-day rates as well as maximum duration volumes. 

d) Assumptions and calculations used in determining the worst case discharge 

 Omitted from Public Information Copies. 

e) Potential for the well to bridge over 

Mechanical failure/collapse of the borehole in a blowout scenario is influenced by several factors including insitu stress, rock strength and fluid velocities at the sandface. Based on the nodal analysis and reservoir 

simulation models outlined above, a seabed blowout would create a high drawdown at the sand face. Given 

the substantial fluid velocities inherent in the worst case discharge, and the scenario as defined where the 

formation is not supported by a cased and cemented wellbore, it is possible that the borehole may 

fail/collapse/bridge over within the span of a few days, significantly reducing outflow rates. However, this 

WCD scenario does not include any bridging or consideration of solids production with the oil and gas. 

f) Likelihood for intervention to stop the blowout. 

Safety of operations is our top priority. Maintaining well control at all times to prevent a blowout is the key 

focus of our operations. Our safe drilling record is based on our robust standards, conservative well design, 

prudent operations practices, competency of personnel, and strong HSE focus. Collectively, these constitute a 

robust system making blowouts extremely rare events. 
Intervention Devices: Notwithstanding these facts, the main scenario for recovery from a blowout event is 

via intervention with the BOP attached to the well. There are built in redundancies in the BOP system to allow 

activation of selected components with the intent to seal off the well bore. As a minimum, the Shell contracted 

rig fleet in the GOM will have redundancies meeting the Interim Final Drilling Safety Rule with respect to 

Remotely Operated Vehicle (ROV) hot stab capabilities, a deadman system, and an autoshear system. 

Shell will be using dynamically positioned rig to drill the MB-1 well. This rig has two shearing rams in the BOP 

for added redundancy. 

Containment: The experience of gaining control over the Macondo well has resulted in a better 

understanding of the necessary equipment and systems for well containment. As a result, industry and 

government are better equipped and prepared today to contain an oil well blowout in deepwater (See page 17 

of the Decision Memorandum dated October 1, 2010). Shell is further analyzing these advances and 

incorporating them into its comprehensive approach to help prevent and, if needed, control another deepwater 

control incident. 

Pursuant to NTL No. 2010-N10, Shell will provide additional information regarding our containment capabilities 

in a subsequent filing. 

g) Availability of a rig to drill a relief well and rig package constraints 

Blowout intervention can be conducted from an ROV equipped vessel, the existing drilling rig or from another 

drilling rig. Shell has an active portfolio of well operations in the GOM which will be supported by a total of 

four to six MODU rigs in 2011 – 2015 timeframe. The dynamically positioned rigs under contract, the Noble 

Danny Adkins and the Noble Bully 1, will be the preferred rigs for blowout intervention work. However, 

moored rigs can also be used in some scenarios. Additionally, in the event of a blowout, there is the distinct 

possibility that other non-contracted rigs in the GOM could be utilized whether for increased expediency or 

better suitability. All efforts will be made at the time to secure the appropriate rig. Shell’s current contracted 

rigs capable of operating at these water depths and reservoir depths without technical constraints are in the 

following table: 

Rig Name Rig Type 

Deepwater Nautilus moored semi 

Noble Jim Thompson moored semi 

Noble Danny Adkins dynamically positioned semi. 

Bully 1** dynamically positioned drill ship 

Above are current as of July 2011. Future modifications may change the rig’s capability. 

* Rig capabilities need to be assessed on a work scope specific basis. 

**Bully 1 estimated arrival Q4, 2011. 

h) Time taken to mobilize a rig, and drill a relief well. 

Relief well operations will immediately take priority and displace any activity from Shell’s contracted rig fleet. 

The list of Shell contracted rigs capable of operating at this location is tabled above. It is expected to take an 

average of 14 days to safely secure the well that the rig is working on, up to the point the rig departs location, 

and a further 1-4 days transit to mobilize to the relief well site depending on distance to travel. The relief well 

will take approximately 124 days to drill down to the last casing string above the blowout zone plus 

approximately 40 days for precision ranging activity to intersect the blowout well bore. Total time to mobilize 

and drill a relief well would be approximately 182 days for this well. 

If a moored rig is chosen to conduct the relief well operations, anchor handlers would be prioritized to prepare 

mooring on the relief well site while the rig is being mobilized. This activity is not expected to delay initiation 

of relief well drilling operations. Shell has 3 deepwater anchor handlers (the Laney, Dino, and Ross Chouest) 

on long term contract to support its moored rigs. 

The closest TLP to the Deimos reservoirs is the Mars “A” TLP. Currently there are no slots available for drilling 

a new well (relief well) from the Mars “A” TLP; and Mars “A” TLP’s DVA rig is insufficient to technically drill an 

MB-01 relief well. Therefore the only way to initiate the drilling of a relief well is with another MODU. 

 
i) Measures proposed to enhance ability to prevent blowout and to reduce likelihood of a 

blowout. 

Shell believes that the best way to manage blowouts is to prevent them from happening. Detailed below are 

the measures employed by Shell with the goal of no harm to people or the environment. The Macondo 

incident has highlighted the importance of these practices. The lessons learned from the investigation are, and 

will continue to be, incorporated into our operations. 

Standards: Shell’s well design and operations adhere to internal corporate standards, the Code of Federal 

Regulations, and industry standards. A robust management of change process is in place to handle un-defined 

or exception situations. Ingrained in the Shell standards for well control is the philosophy of multiple barriers 

in the well design and operations on the well. 

Risk Management: Shell believes that prevention of major incidents is best managed through the systematic 

identification and mitigation process (Safety Case). All Shell contracted rigs in the GOM have been operating 

with a Safety Case and will continue to do so. A Safety Case requires both the owner and contractors to 

systematically identify the risks in drilling operations and align plans to mitigate those risks; an alignment 

which is critical before drilling begins. 

Well Design Workflow: The Well Delivery Process (WDP) is a rigorous internal assurance process with 

defined decision gates. The WDP leverages functional experts (internal and external) to examine the well 

design at the conceptual and detailed design stages for robustness before making a recommendation to the 

management review board. Shell’s involvement in global deepwater drilling, starting in the GOM in the mid1980’s, provides a significant depth and breadth of internal drilling and operational expertise. Third party 

vendors and rig contractors are involved in all stages of the planning, providing their specific expertise. A Drill 

the Well On Paper (DWOP) exercise is conducted with rig personnel and vendors involved in execution of the 

well. This forum communicates the well plan, and solicits input as to the safety of the plan and procedures 

proposed. 

Well and rig equipment qualification, certification, and quality assurance: All rigs will meet all 

applicable rules, regulations, and Notice to Lessees. Shell works closely with rig contractors to ensure proper 

upkeep of all rig equipment, which meets or exceeds the strictest of Shell, industry, or regulatory 

requirements. Well tangibles are governed by our internal quality assurance/control standards and industry 

standards. 

MWD/LWD/PWD Tools: Shell intends to use these tools at MB-1. The MWD/LWD/PWD tools are run on 

the drill string so that data on subsurface zones can be collected as the well advances in real time instead of 

waiting until the drill string is pulled to run wireline logs. Data from the tools are monitored and interpreted 

real time against prognosis to provide early warning of abnormal pressures to allow measures to be taken to 

progress the well safely. 

Mud Logger: Mud logging personnel continually monitor returning drilling fluids for indications of

hydrocarbons, utilizing both a hot wire and a gas chromatograph. An abrupt increase in gas or oil carried in 

the returning fluid can be an indication of an impending kick. The mud logger also monitors drill cuttings 

returned to the surface in the drilling fluid for changes in lithology that can be an indicator that the well has 

penetrated or is about to penetrate a hydrocarbon-bearing interval. Mud logging instruments also monitor

penetration rate to provide an early indication of drilling breaks that show the bit penetrating a zone that could 

contain hydrocarbons. The mud logging personnel are in close communication with both the offshore drilling 

foremen and onshore Shell representative(s) to report any observed anomalies so appropriate action can be 

taken. 

Remote Monitoring: The Real Time Operating Center has been used by Shell to complement and support 

traditional rig-site monitoring since 2003. Well site operations are lived virtually by onshore teams consisting of 

geoscientists, petrophysicists, well engineers, and 24/7 monitoring specialists. The same real time well control 

indicators monitored by the rig personnel are watched by the monitoring specialist for an added layer of 

redundancy. 

Competency and Behavior: A structured training program for Well Engineers and Foreman is practiced, 

which includes internal professional examinations to verify competency. Other industry training in well control, 

such as by International Association of Drilling Contractors (IADC) and International Well Control Forum 

(IWCF) are also mandated. Progressions have elements of competency and Shell continues to have 
comprehensive internal training programs. The best systems and processes can be defeated by lack of 

knowledge and/or improper values. We believe that a combination of HSE tools (e.g. stop work, pre-job 

analysis, behavior based safety, DWOPs, audits), management HSE involvement and enforcement (e.g. 

compliance to life saving rules) have created a strong safety culture in our operations. 

j) Measures to conduct effective and early intervention in the event of a blowout. 

The response to a blowout is contained in our Well Control Contingency Plan (WCCP) which is a specific 

requirement of our internal well control standards. The WCCP in turn is part of the wider emergency response 

framework within Shell that addresses the overall organization response to an emergency situation. Resources 

are dedicated to these systems and drills are run frequently to test preparedness (security, medical, oil spill, 

and hurricane). This same framework is activated and tested during hurricane evacuations, thereby 

maintaining a fresh and responsive team. 

The WCCP specifically addresses implementing actions at the emergency site that will ensure personnel safety, 

organizing personnel and their roles in the response, defining information requirements, establishing protocols 

to mobilize specialists and pre-selecting sources, and developing mobilization plans for personnel, material and 

services for well control procedures. The plan references individual activity checklists, a roster of equipment 

and services, initial information gathering forms, a generic description of relief well drilling, strategy and 

guidelines, intervention techniques and equipment, site safety management, exclusion zones, and re-boarding. 

As set forth in 3f of this document, Shell is currently analyzing recent advances in containment technology and 

equipment and will incorporate them as they become available. 

k) Arrangements for drilling a relief well 

The size of the Shell contracted rig fleet in the GOM from 2010-2015 ensures that there is adequate well 

equipment (e.g. casing and wellhead) available for relief wells. Rigs and personnel will also be readily available 

within Shell, diverted from their active roles elsewhere. Resources from other operators can also be leveraged 

should the need arise. Generally, relief well plans will mirror the blowout well, incorporating any learning on 

well design based on root cause analysis of the blowout. A generic relief well description is outlined in the 

WCCP. 

l) Assumptions and calculations used in approved or proposed OSRP 

Shell has submitted MC-762 A (Olympus MB-1) as the new exploration worst-case scenario to the BOEMRE for 

inclusion in our Regional OSRP. 

Shell has designed a response program (Regional OSRP dated August 2011) based upon a regional capability 

of responding to a range of spill volumes, from small operational spills up to and including the WCD from an 

exploration well blowout. Shell’s program is developed to fully satisfy federal oil spill planning regulations. The 

Regional OSRP presents specific information on the response program that includes a description of personnel 

and equipment mobilization, the incident management team organization, and the strategies and tactics used 

to implement effective and sustained spill containment and recovery operations. 

G. Oil Spill Financial Responsibility (OSFR)

Shell Offshore Inc (SOI), BOEM Operator Number 0689, has demonstrated oil spill financial responsibility for the 

facilities proposed in the EP according to 30 CFR Parts 250 and 253, and NTL No. 2008-N05, “Guidelines for Oil 

Spill Financial Responsibility for Covered Facilities.” 

H. Deepwater well control statement

Shell Offshore Inc (SOI), BOEM Operator Number 0689, has the financial capability to drill a relief well and 

conduct other emergency well control operations. 

I. Suspension of Production

Information regarding Suspension of Production is not included in this EP as such information is only 

necessary in the case of DOCDs. 
SECTION 3: GEOLOGICAL AND GEOPHYSICAL INFORMATION

A. Geological description

Omitted from Public information copies. 

B. Structure Contour Map(s)

Omitted from Public information copies. 

C. Interpreted 2D and/or 3D Seismic line(s)

Omitted from Public information copies. 

D. Geological Structure Cross-section(s)

Omitted from Public information copies. 

 

E. Shallow Hazards Report

Shell submitted an Initial Exploration Plan (EP N-2993) and Hazards Report #1188-1062 dated April 26, 

1988, prepared by Fugro-McClelland. This report and EP were approved on June 3, 1988, by the Minerals 

Management Service. Another report by GEMS, #0403-643 dated August 26, 2003, entitled “Geologic and 

Stratigraphic Assessment Block 762, OCS-G 7957, Mississippi Canyon Area, Gulf of Mexico” was accepted 

by the Minerals Management Service on October 16, 2003. 

F. Shallow Hazards Assessment

Shell is now submitting a Supplemental EP for 24 proposed locations in Mississippi Canyon 807 (Proposed 

Locations A through X). These 24 locations are all located within 500 feet of one central location: 

X = 919,072, Y = 10,225,602 

Seafloor investigation is based on the C&C report number 083985-084126: Archaeological and Hazard 

Report, Blocks 762-763, 806-807, and Vicinity, Mississippi Canyon Area, dated June 2009. 

Proposed Locations

Proposed Location A, MC 807: 

X = 919,005.00 285’ FWL 

Y = 10,225,610.00 7030’ FNL 

Proposed Location B, MC 807: 

X = 919,039.00 319’ FWL 

Y = 10,225,597.00 7043’ FNL 

Proposed Location C, MC 807: 

X = 919,038.00 318’ FWL 

Y = 10,225,633.00 7007’ FNL 

Proposed Location D, MC 807: 

X = 919,052.00 332’ FWL 

Y = 10,225,613.00 7027’ FNL 

Proposed Location E, MC 807: 

X = 919,020.00 300’ FWL 

Y = 10,225,590.00 7050’ FNL 
Proposed Location F, MC 807:

X = 919,027.00 307’ FWL 

Y = 10,225,613.00 7027’ FNL 

Proposed Location G, MC 807: 

X = 919,066.00 346’ FWL 

Y = 10,225,628.00 7012’ FNL 

Proposed Location H, MC 807: 

X = 919,077.00 357’ FWL 

Y = 10,225,648.00 6992’ FNL 

Proposed Location I, MC 807: 

X = 919,099.00 379’ FWL 

Y = 10,225,651.00 6989’ FNL 

Proposed Location J, MC 807: 

X = 919,080.00 360’ FWL 

Y = 10,225,608.00 7032’ FNL 

Proposed Location K, MC 807: 

X = 919,113.00 393’ FWL 

Y = 10,225,631.00 7009’ FNL 

Proposed Location L, MC 807: 

X = 919,091.00 371’ FWL 

Y = 10, 225,627.00 7013’ FNL 

Proposed Location M, MC 807: 

X = 919,045.00 325’ FWL 

Y = 10,225,553.00 7087’ FNL 

Proposed Location N, MC 807: 

X = 919,065.00 345’ FWL 

Y = 10,225,560.00 7080’ FNL 

Proposed Location O, MC 807: 

X = 919,078.00 358’ FWL 

Y = 10,225,576.00 7064’ FNL 

Proposed Location P, MC 807: 

X = 919,031.00 311’ FWL 

Y = 10,225,573.00 7067’ FNL 

Proposed Location Q, MC 807: 

X = 919,064.00 344’ FWL 

Y = 10,225,596.00 7044’ FNL 

Proposed Location R, MC 807: 

X = 919,053.00 333’ FWL 

Y = 10,225,577.00 7063’ FNL 

Proposed Location S, MC 807: 

X = 919,092.00 372’ FWL 

Y = 10,225,591.00 7049’ FNL 

Proposed Location T, MC 807: 

X = 919,102. 00 382’ FWL 

Y = 10,225,611.00 7029’ FNL 
 Proposed Location U, MC 807: X = 919,124.00 404’ FWL

 10,225,614.00 Y= 7026’ FNL

Proposed Location V, MC 807: 

X = 919,106.00 386’ FWL 

Y = 10,225,570.00 7069’ FNL 

Proposed Location W, MC 807: 

X = 919,139.00 419’ FWL 

Y = 10,225,594.00 7046’ FNL 

Proposed Location X, MC 807: 

X = 919,117.00 397’ FWL 

Y = 10,225,591.00 7049’ FNL

Mississippi Canyon 807, Proposed Locations A thru X will be located in a water depth of approximately 

3028 feet. Proposed Locations A thru X will be located 2259 feet northwest of Shell’s previously drilled 

MC807 #1 wellsite. Minor shallow buried faulting (3 to 75 feet below the mud line) and buried landslide 

features (from 75 feet below the mud line) are identified in the vicinity of Proposed Locations A thru X. 

There is no other evidence of seafloor or near-surface amplitudes or fluid expulsion features associated 

with these minor, shallow buried faults. 

An Industrial Waste Dump site is identified west of MC 807, in MC 805. This dumpsite consists of 55-

gallon drums that have deteriorated over time. Some of the drums had been dropped outside of the limits 

of the site and are identified on the Geologic Features Map (Map 5) of the GEMS report. Within 2000 feet 

of the 24 proposed locations, there are 18 sonar targets identified as potential barrels with a 50 foot 

recommended avoidance, 4 sonar targets identified as modern debris with 100 foot avoidance, and an 

additional 15 sonar targets have been identified as potential barrels in the additional 1000’ buffer zone 

surrounding Proposed Locations A thru X. 

Attached is Shell’s Waste Barrel Avoidance and Release Response Plan for Mississippi Canyon. 

There are several flowlines and umbilicals in the vicinity of the site of Proposed Locations A thru X. Shell’s 

Europa flowlines and umbilicals are approximately 1600 feet northeast of Proposed Locations A thru X. A 

500 foot avoidance zone has been placed around all flowlines and umbilicals. Proposed Locations A thru X 

will not interfere with any of the existing flowlines and umbilicals in the area.

The stratigraphy at the sites of Proposed Locations A thru X consists of approximately 590-foot thick unit 

of very soft pelagic clay drape material overlying soft to firm hemipleagic silts and clays inter-bedded with 

chaotic mass-transport deposits. A minor buried fault will be penetrated approximately 9 to 72 feet below 

the mud line in 11 of the proposed wellsites. The casing program for Proposed Locations A thru X is 

designed for this minor buried fault penetration. Unit 2, approximately 590 to 1231 feet below the mud 

line, consists of approximately 641 feet of mud-filled over-bank deposits. Unit 3 is the Blue Unit, identified 

1231 to 2559 feet below the mud line. Unit 3 consists of 262 feet of discontinuous, sandy channel-levee 

deposits and 1066 feet of chaotic mass-transport deposits of sand, silt and clay and stratified turbidities of 

interbedded sand, silt and clay. Unit 4 is identified 2559 to 3499 feet below the mud line, consisting of 

940 feet of stratified mud-dominated turbidites, chaotic mass-transport deposits and discontinuous, 

moderate amplitude deposits. Unit 5 consists of 1489 feet of discontinuous, mud-rich mass transport 

deposits, sandy slope fan channel sediments and chaotic disrupted turbidite deposits. 

Amplitude anomalies are identified 500’ west of the proposed locations in Unit 4 (2559 to 3499 feet below 

the mud line), and 570’ feet west northwest of the proposed locations in Unit 5 (3499 to 4988 feet below 

the mud line). There are no other anomalies or bright spots identified within 2000’ feet of Proposed 

Locations A thru X. Proposed Locations A thru X will not penetrate any amplitude anomalies. 

Moderate to moderate high potential for shallow water flow is identified 1493 to 2559 feet below the mud 

line and 3499 to 4252 feet below the mud line. Moderate potential for shallow water flow is identified 

2967 to 3499 feet below the mud line. Low potential for shallow water flow is identified from Seafloor to 

1493 feet below the mud line, 2559 to 2967 feet below the mud line, and 4252 to 4988 feet below the 

mud line. The casing program for Mississippi Canyon 807, Proposed Locations A thru X is designed to 

minimize flow potential. 
Moderate to moderate high potential for shallow gas is identified 3499 to 4252 feet below the mud line. 

Low potential for shallow gas is identified from Seafloor to 3499 feet below the mud line, and 4252 to 

4988 feet below the mud line. 

Based on a high-resolution geophysical survey, consisting of frequency enhanced 3-D seismic, Enhanced 

Surface Renderings (ESR’s), ESR’s with amplitudes applied, and AUV high-resolution data, Mississippi 

Canyon 807, Proposed Locations A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, and X 

appear suitable for the planned activity. 

Kevin Bradford/ Larry Gibson Arlette C. Nunez 

Geophysicist/Geologist Shallow Hazard Interpreter 

G. High-Resolution Seismic Lines

Omitted from Public information copies. Attached is the ESR. 

H and I Stratigraphic Column with Time vs depth table

Omitted from Public information copies. 

J. Geochemical Information

This information is not required for Plans submitted in the GOM Region. 

K. Future G&G Activities

This information is not required for Plans submitted in the GOM Region. 
S-12130 SHELL 12" (Casi ng) S-12129 SHELL 8"

S-12126 SHELL 12" (Casi ng) S-12125 SHELL 8"

S-12127 SHELL 3" (Umbi l i cal )

S-12128 SHELL 6" (Umbi l i cal )

S-12237 SHELL 5"

S-12239 SHELL 5" (Umbi l i cal ) S-12238 SHELL 5"

S1

0360

SHELL

1

8"

S1

0222

SHELL

1

4"

S12128

SHELL

6"

(Umbi

l

i

cal

)

S12127

SHELL

3"

(Umbi

l

i

cal

)

S-15687 SHELL 8"

S-15684 SHELL 8"

S1

5689

SHELL

6"

S- 16127 ATP 10" -12" (Permi t t ed) S-14835 SHELL 1"

S-12130 SHELL 12"

S-12129 SHELL 8" (Casi ng)

S- 12126 SHELL 12" S-12125 SHELL 8" (Casi ng)

S-14835 SHELL 1"

Center

807-7

806-2

806-3

807-1

807-2

807-3

807-4

807-5

807-6

Mars TLP

Mississippi Canyon 807, Proposed Locations A thru X

0 2,500 5,000 10,000 

2000' Wellsite

Clearance for

Prop Loc A thru X

3000' Circle

(2000' Wellsite

Clerance +

1000' Buffer)
OLYMPUS Host – MARS “B” Development 

MISSISSIPPI CANYON BLOCK 807 

Waste Barrel Avoidance and Release 

Response in the Mississippi Canyon 

Area 

Project OLYMPUS Host – MARS “B” Development 

Document Title Waste Barrel Avoidance and Release 

Response in the Mississippi Canyon Area 

Document Number MRB-100-HX-0505-0000002-000

Document Revision REV 2 

Version Code Not Applicable 

Document Status Issued for Review 

EIS Discipline / Document Type Hazard Analysis Report

Originator / Author Robert Kuehn 

Classification Restricted 

ECCN EAR 99 

Issue Date 10/20/10 

Revision History is shown on next page 
Document Number -Rev Page 2 of 8 

RESTRICTED

REVISION HISTORY 

Rev # Date of 

Issue 

Issue Description Originator Reviewer Approver 

2 10/20/10 Formalized existing 

document into 

Document Mgmt 

program 

RB Kuehn RB Kuehn Nilesh Popat 

 

 

 

 

 

 

 

 

Summary 
Document Number -Rev Page 3 of 8 

RESTRICTED

Contents 

PURPOSE ............................................................................................................................ 4

REVISION HISTORY ....................................................................................................... 4

BACKGROUND ................................................................................................................. 4

NORMAL OPERATIONS ....................................................................................................... 5

DECONTAMINATION OF EQUIPMENT ................................................................................... 6
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

4 of 8 

Purpose 

This document provides expectations and guidance for avoiding, and responding to a release of 

the contents of, a seafloor waste barrel. The procedures below describes Shell’s expectations for 

routine barrel avoidance, data management, and response to inadvertent release of barrel 

contents. 

Applicability 

This document applies to all ROV, anchor and other operations which could cause a seafloor 

barrel rupture. 

Changes to this procedure must be approved by BOEMRE.1 

Revision History 

Date Person Revision 

12/16/08 RBKuehn Incorporated comments from MMS2 and issued as final. 

8/16/10 RBKuehn Incorporated comment from BOEMRE3 to include New Orleans District 

manager in the notification of Step 2 of the section Barrel Impact Reporting. 

Also revised all relevant references to MMS as BOEMRE 

10/20/10 RBKuehn 3⁄4 In Background, added in summary of suspected materials disposed at the 

site, based on research of the site in public records. 

3⁄4 In section on Equipment Decontamination- Decon Procedure:

o clarified what types of detergents are preferred/allowed, using the 

NPDES Vessel General Permit as a guide. 

o Expanded on appropriate PPE and other personnel precautions 

o Noted a need for secondary containment as appropriate 

Significant changes to the text are shown in yellow shade. 

3⁄4 Added page numbers and cleaned up format. 

 

3⁄4 Issued as REV 2 

Background 

Various projects will be carried out in an area of the Mississippi Canyon known to contain 

barrels of chemical waste. 

 

1 Per MMS approval of West Boreas Supplemental Exploration Plan, MS 5231 December 16, 2008 

Control No. S-07273, Lease(s) OCS-G07957, Block 762, Mississippi Canyon Area OCS-G07962, Block 806, 

Mississippi Canyon Area

2 Per MMS approval of West Boreas Supplemental Exploration Plan, MS 5231 December 16, 2008 

Control No. S-07273, Lease(s) OCS-G07957, Block 762, Mississippi Canyon Area OCS-G07962, Block 806, 

Mississippi Canyon Area

3

 Per BOEM approval of the Supplement to the Conceptual DWOP for Mars B project, 8/12/10, MS 5220 
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

5 of 8 

• The barrels were discharged in this area in the 1970’s under government approved 

permits. 

• The content, and its toxicity, of each individual barrel is not known. However, there are 

records of a wide range of industrial waste materials that were disposed in the barrels 

including chlorinated hydrocarbons and liquid metal salts. Below is a summary of the 

barrel contents based on available records. 

1. Metallic sodium and calcium; calcium oxide, sodium oxide, and inert salts.4 

2. 80-90% dichlorobutene, 20% organic high-boilers, and 1% quaternary 

ammonium salts. “Other wastes produced from the manufacture of fungicides 

and herbicides”.5

• Within the area there are/could be many hundreds of waste barrels. Many of the barrels 

may have released their contents over time. However, an unknown number of barrels still 

look intact, and they may or may not still contain their original content. Also, as some of 

the barrels contained metal based solid waste, some of the barrels that no longer look 

intact may still contain some waste. 

• Extensive sonar surveys of the area exist and are available for planning purposes. 

Potential Hazards 

Although there are no records of any issues regarding the barrels during the many years of Oil 

and Gas operations in the Mississippi Canyon area, the following potential hazards exist: 

• Personnel exposure or equipment damage due to adherence of waste chemicals to 

recovered subsea equipment 

• Equipment damage from sodium exposure to water (very vigorous reaction). 

Normal Operations 

For normal operations, all contractors and Shell employees must meet the following 

expectations: 

1. Shell’s over-arching policy is to avoid barrel contact. 

2. Press releases making any reference to the chemical waste or barrels, or any incidents 

involving any chemical waste or barrels, will require the express written permission from 

 

4

 EPA Permit Application No. 730D009E from Ethyl Corp, March 1, 1977, Public Notice April 20, 1977, 5

 Chapter 5 “Ocean Discharge” in the book Assessing Potential Ocean Pollutants, A Report of the Study Panel on Assessing 

Potential Ocean Pollutants. National Academy of Sciences, Washington DC, 438 pp. This document details DuPont’s application 

to dispose of the following at the ocean disposal site
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

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Shell. 

3. All recorded video material is confidential and the property of Shell (standard contract 

provision). 

If during normal ROV operations there is a discovery of any potential archaeological 

resource (i.e., cannot be definitively identified as waste barrel/barrel remnant, modern debris, 

or refuse), any seafloor-disturbing activities in its proximity, must be stopped, the discovery 

must be reported to Dr. Chris Horrell at 504-736-2796, and further instructions must be 

obtained before proceeding. 

4. Equipment Placement/Stand-off Distance

4.1. A safe stand-off distance from the waste barrels is considered 10m (33ft). Care must be 

taken that flexible components (e.g. ROV tether, anchor lines, seismic cables) are 

controlled as well (e.g. don’t drag through a barrel field). 

4.2. If a seafloor action will generate cuttings or debris, increase the stand-off distance as 

needed to avoid debris contact with nearby barrels. 

4.3. Do not investigate any barrels or remainders of barrels. Remain the minimum stand-off 

of 10m (33ft) at all times. 

4.4. Survey the anchor/pile/export locations with an ROV to ensure barrel avoidance. 

4.5. Record the (approximate) location of any chemical waste barrel seen, if feasible, 

without getting closer than the 10m (33ft) stand-off distance. 

5. Contact the Shell EP Company Environmental Duty Phone for any questions or concerns. 1-

504-390-1330 

6. Decontamination of Equipment: In the event of contact with a barrel contents decontaminate 

equipment per Decontamination of Equipment below. 

7. Make reports of barrel contact/rupture per Barrel Release Reporting below. 

Decontamination of Equipment 

1. General 

In the unlikely case that contact is suspected or has been made with any wastes from a barrel, 

appropriate action needs to be taken to guarantee the topside safety of personnel handling the 

equipment (e.g. ROV, anchor lines, etc). 

It is left solely to the judgment of the Person-in-Charge of the 

equipment/vessel to determine if it is necessary to abandon all or part of 

the equipment on the sea floor. 

2. Decon Procedure 
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

7 of 8 

Based on various factors6

, Shell recommends the following: 

2.1. Use the ocean to “wash” the equipment (e.g. fly an ROV for at least an hour at depth 

high enough above sea floor to prevent umbilical dragging or other disturbance of the 

sea floor). For other equipment, provide any movement through the water column 

that’s possible, again avoiding seafloor dragging. 

2.2. Retrieve the equipment to the surface, but do not bring onboard if feasible. 

2.3. Hose the equipment off before retrieving onto the vessel. Use as high a water flow as 

is available/safe. CAUTION- detergent/soap may be used BUT in as low a quantity 

as practicable to minimize foam. Only non-toxic and phosphate free cleaners and 

detergents may be used. Furthermore, cleaners and detergents should not be caustic or 

only minimally caustic and should be biodegradable7. 

2.4. Avoid physical contact with the equipment, and keep the equipment off the vessel at 

this point.. 

2.5. Dunk the equipment back in the sea and “wash” the equipment for approximately 15 

minutes. 

2.6. Retrieve the equipment to the surface. Before recovering, visually inspect the 

equipment, umbilical, cable surfaces with binoculars for signs of corrosion, 

discoloration, air reaction such as fuming/smoking, or any other signs of chemical 

contact. Rewash and dunk the equipment as needed. 

2.7. Retrieve the equipment onto the back deck. Monitor the equipment and surrounding 

storage area for indications of chemical contamination (corrosion, discoloration, air 

reaction such as fuming/smoking, etc). Establish secondary containment as necessary 

to collect any potentially contaminated drips. 

2.8. Only essential personnel should be allowed near the equipment, once retrieved on the 

back deck. 

2.9. While performing cleaning operations on the equipment, involving contact with 

potentially contaminated surfaces, personal protective equipment must be worn 

including, but not limited to: safety eye goggles, safety clothing such as coverall and 

 6 Shell assumes, for purposes of this decontamination guidance, that: 

• The most toxic material identified in the disposal area’s permits and other available documents is involved . However Shell cannot guarantee 

there are not other toxic materials present than those identified in the permits and other documents. 

• It is assumed that the materials do not chemically interact with the materials of the ROV, its tools and equipment. 

7

 The NPDES General Permit for Discharges Incidental to the Normal Operation of a Vessel provides insight into managing any 

washing. Also, EPA provides the following definitions: 

“Non-toxic” soaps, cleaners, and detergents means these materials which do not exhibit potentially harmful characteristics as 

defined by the Consumer Product Safety Commission regulations found at 16 CFR Chapter II, Subchapter C, Part 1500. 

“Phosphate Free” soaps, cleaners, and detergents means these materials which contain, by 

weight, 0.5% or less of phosphates or derivatives of phosphates.
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

8 of 8 

aprons, Nitrile type chemical resistant industrial-safety gloves, and PVC boots. 

2.10. Wash hands thoroughly and take a shower after performing cleaning operations on 

the equipment. 

2.11. Avoid drinking liquids or eating food in the work area. 

2.12. If contamination is still suspected, consult with the Shell representatives/management 

for further actions including additional washing, abandonment on the seafloor, 

segregated storage on the boat, wrapping the equipment partially or fully in plastic 

sheeting, etc. 

2.13. Document all actions and results in a log. 

Barrel Impact Reporting 

1. Initial reporting:

1.1. Equipment operator is to inform the Shell onsite representative and the Shell 

operations supervisor on duty. 

1.2. The Shell onsite representative or the Shell operations supervisor will call the 

SEPCO Environmental Duty Engineer at 1-504-390-1330. As a back-up, call 337-

281-0783 (Rob Kuehn). 

• The call should be made at the earliest convenience. 

• Be prepared to report the lat/long of the ruptured barrel (not the surface location) 

and water depth. 

2. The SEPCO Environmental Duty Engineer will call 

• the regulatory Affairs Duty Phone 504-782-7823, 

• Mr. Broussard of the BOEMRE (504-736-3245) and 

• BOEMRE New Orleans District Manager 

to report the event. The call should include the lat/long and any circumstances of note. 

3. Follow-up Reporting

The SEPCO Environmental Duty Engineer or Rob Kuehn follows up with an email to 

Mr. Broussard of BOEMRE. 

The BOEMRE have requested submission of a copy of whatever relevant video is 

available for the event period. No dedicated video survey is required for a barrel rupture 

(i.e. just be prepared to submit whatever video was obtained as normal part of the 

activities). BOEM has agreed we can submit any video after the project is completed. 
SECTION 4: Hydrogen Sulfide 

A. Concentration 

 0 ppm. 

B. Classification

Based on CFR 250.490(c) SOI requests that the Regional Supervisor, Field Operations, determine the 

zones in the proposed drilling operations in this plan to be classified as an area where the absence of H2S 

has been confirmed. 

C. Modeling Report

We do not anticipate to encounter or handle H2S at concentrations greater than 500 parts per million 

(ppm) and therefore have not included modeling for H2S. 

 
5. Mineral Resource Conservation Information

Information regarding Mineral Resource Conservation is not included in this EP as such information 

is only necessary in the case of DOCDs. 
SECTION 6: Biological, Physical, and Socioeconomic Information

A. Chemosynthetic Communities Report

Biological Information

NTL 2009-G40, dated January 27, 2010, for water depths greater than 984 feet: 

Mississippi Canyon 807, Proposed Locations A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, 

S, T, U, V, W, and X: 

• Features or areas that could support high-density chemosynthetic communities 

are not within 2,000 feet of each proposed mud and cuttings discharge location. 

History

Shell submitted an Initial Exploration Plan (EP N-2993) and hazards report #1188-1062 dated April 

26, 1988, prepared by Fugro-McClelland. This report and EP were approved on June 3, 1988, by the 

Minerals Management Service. Another report by GEMS, #0403-643 dated August 26,2003, entitled 

Geologic and Stratigraphic Assessment Block 762 (OCS-G 7957 Mississippi Canyon Area, Gulf of 

Mexico) was accepted by the Minerals Management Service on October 16, 2003. 

Shell is now submitting a Supplemental EP for 24 proposed locations in Mississippi Canyon 807 

(Proposed Locations A through X). These 24 locations are all located within 500 feet of one central 

location: 

X = 919,072, Y = 10,225,602. 

Seafloor investigation is based on the C&C report number 083985-084126: Archaeological and Hazard 

Report, Blocks 762-763, 806-807, and Vicinity, Mississippi Canyon Area, dated June 2009. 

Locations

Proposed Location A, MC 807: 

X = 919,005.00 285’ FWL 

Y = 10,225,610.00 7030’ FNL 

Proposed Location B, MC 807: 

X = 919,039.00 319’ FWL 

Y = 10,225,597.00 7043’ FNL 

Proposed Location C, MC 807: 

X = 919,038.00 318’ FWL 

Y = 10,225,633.00 7007’ FNL 

Proposed Location D, MC 807: 

X = 919,052.00 332’ FWL 

Y = 10,225,613.00 7027’ FNL 

Proposed Location E, MC 807: 

X = 919,020.00 300’ FWL 

Y = 10,225,590.00 7050’ FNL 

Proposed Location F, MC 807: 

X = 919,027.00 307’ FWL 

Y = 10,225,613.00 70267’ FNL 

Proposed Location G, MC 807: 

X = 919,066.00 346’ FWL 

Y = 10,225,628.00 7012’ FNL 
Proposed Location H, MC 807: 

X = 919,077.00 357’ FWL 

Y = 10,225,648.00 6992’ FNL 

Proposed Location I, MC 807: 

X = 919,099.00 379’ FWL 

Y = 10,225,651.00 6989’ FNL 

Proposed Location J, MC 807: 

X = 919,080.00 360’ FWL 

Y = 10,225,608.00 7032’ FNL 

Proposed Location K, MC 807: 

X = 919,113.00 393’ FWL 

Y = 10,225,631.00 7009’ FNL 

Proposed Location L, MC 807: 

X = 919,091.00 371’ FWL 

Y = 10, 225,627.00 7013’ FNL 

Proposed Location M, MC 807: 

X = 919,045.00 325’ FWL 

Y = 10,225,553.00 7087’ FNL 

Proposed Location N, MC 807: 

X = 919,065.00 345’ FWL 

Y = 10,225,560.00 7080’ FNL 

Proposed Location O, MC 807: 

X = 919,078.00 358’ FWL 

Y = 10,225,576.00 7064’ FNL 

Proposed Location P, MC 807: 

X = 919,031.00 311’ FWL 

Y = 10,225,573.00 7067’ FNL 

Proposed Location Q, MC 807: 

X = 919,064.00 344’ FWL 

Y = 10,225,596.00 7044’ FNL 

Proposed Location R, MC 807: 

X = 919,053.00 333’ FWL 

Y = 10,225,577.00 7063’ FNL 

Proposed Location S, MC 807: 

X = 919,092.00 372’ FWL 

Y = 10,225,591.00 7049’ FNL 

Proposed Location T, MC 807: 

X = 919,102. 00 382’ FWL 

Y = 10,225,611.00 7029’ FNL 

Proposed Location U, MC 807: 

X = 919,124.00 404’ FWL 

Y = 10,225,614.00 7026’ FNL 

Proposed Location V, MC 807: 

X = 919,106.00 386’ FWL 

Y = 10,225,570.00 7069’ FNL 
Proposed Location W, MC 807: 

X = 919,139.00 419’ FWL 

Y = 10,225,594.00 7046’ FNL 

Proposed Location X, MC 807: 

X = 919,117.00 397’ FWL 

Y = 10,225,591.00 7049’ FNL 

Mississippi Canyon 807, Proposed Locations A thru X will be located in a water depth of 

approximately 3028 feet. Minor shallow buried faulting (3 to 75 feet below the mud line) and buried 

landslide features (from 75 feet below the mud line) are identified in the vicinity of Proposed 

Locations A thru X. There is no other evidence of seafloor or near-surface amplitudes or fluid 

expulsion features associated with these minor, shallow buried faults. Mississippi Canyon 807, 

Proposed Locations A thru X will not disturb any high-density areas of chemosynthetic communities. 

The surface location for Shell’s previously drilled MC 807 #1 wellsite will be positioned 2259 

southeast of Shell’s Mississippi Canyon 807 Proposed Locations A thru X. The surface location for 

Shell’s previously drilled MC 806 #2 wellsite will be positioned 2827 north of Shell’s Mississippi 

Canyon 807 Proposed Locations A thru X. These wellsites will be within the additional 1000’ buffer 

around the 2000’ wellsite clearance. There are no other locations within the 2000 foot site clearance 

or 1000 foot buffer zone. Avoidance zones (500’) for Shell’s previously drilled MC 806 No. 1, 807 No. 

2, 807 No. 3 and 807 No. 5 wellsites will be located within the 1000’ buffer zone. Proposed Locations 

A thru X will be positioned 6302 feet south of Shell’s previously drilled MC 807 Mars TLP platform. 

Proposed Locations A thru X will not interfere with any previously drilled wellsites.

An Industrial Waste Dump site is identified west of MC 807, in MC 805. This dumpsite consists of 55-

gallon drums that have deteriorated over time. Some of the drums had been dropped outside of the 

limits of the site and are identified on the Geologic Features Map (Map 5) of the GEMS report. Within 

2000 feet of the 24 proposed locations, there are 18 sonar targets identified as potential barrels with 

a 50 foot recommended avoidance, 4 sonar targets identified as modern debris with 100 foot 

avoidance, and an additional 15 sonar targets have been identified as potential barrels in the 

additional 1000’ buffer zone surrounding Proposed Locations A thru X. 

See attachments to SEP Section 3 for Shell’s Waste Barrel Avoidance and Release Response Plan for 

Mississippi Canyon. 

The table below lists the sonar contact number, coordinates, distance, direction and avoidance 

footage requested, for all contacts within 2000’ of Proposed Locations A thru X. 

Sonar 

Contact 

No. 

X Y 

Distan

ce 

from 

Prop 

LocA 

thruX 

Center 

Direction 

from Prop 

Loc A thru X 

Center 

Avoidan

ce 

Footage 

2259 917247 10224628 1884 Southwest 50 

2260 917271 10224637 2043 Southwest 50 

2265 917391 10225464 1687 West 50 

2266 917430 10225206 1689 West 50 

2267 917452 10224600 1905 Southwest 50 

2273 917609 10226930 1976 Northwest 100 

2274 917631 10226815 2069 Northeast 50 

2275 917642 10224149 2039 Southwest 100 

2276 917784 10225658 1289 West 50 

2281 917923 10225173 1226 West 50 

2286 918013 10224072 1861 Southwest 100 

2289 918285 10224227 1584 Southwest 50 

2291 918392 10225477 691 West 50 

2293 918408 10225483 675 West 100 
2294 918468 10223757 1941 Southwest 50 

2297 918550 10225152 689 Southwest 50 

2302 918619 10224786 933 Southwest 50 

2304 918714 10224709 962 Southwest 50 

2311 919043 10224820 783 South 50 

2318 919158 10223585 2019 South 50 

2322 919226 10223782 1827 South 50 

2324 919257 10223787 1824 South 50 

The table below lists the sonar contact number, coordinates, distance, direction and avoidance 

footage requested, for all contacts within the additional 1000’ buffer zone for the 2000’ clearance of 

Proposed Locations A thru X. 

Sonar 

Contact 

# 

X Y 

Distan

ce 

from 

Prop 

Loc A 

thru X 

Center 

Direction 

from Prop 

Loc A thru X 

Center 

Avoidance 

Footage 

2235 916317 10226007 2785 West 50 

2236 916324 10226430 2870 West 50 

2241 916538 10227232 3013 Northwest 50 

2242 916562 10227170 2960 Northwest 50 

2249 916843 10226972 2616 Northwest 50 

2250 916855 10227604 2987 Northwest 50 

2257 917041 10226401 2183 West 50 

2271 917539 10227273 2268 Northwest 50 

2282 917951 10223539 2348 Southwest 50 

2284 918013 10227991 2603 Northwest 50 

2330 919429 10228097 2520 North 50 

2342 919746 10223089 2602 South 50 

2344 919829 10223060 2652 South 50 

2363 920742 10227796 2757 Northeast 50 

2386 921356 10224756 2436 Southeast 50 

There are several flowlines and umbilicals in the vicinity of the site of Proposed Locations A thru X. 

Shell’s Europa flowlines and umbilicals are approximately 1600 feet northeast of Proposed Locations 

A thru X. A 500 foot avoidance zone has been placed around all flowlines and umbilicals. Proposed 

Locations A thru X will not interfere with any of the existing flowlines and umbilicals in the area.

Based on a high-resolution geophysical survey, consisting of frequency enhanced 3-D seismic, 

Enhanced Surface Renderings (ESR’s), ESR’s with amplitudes applied, and AUV high-resolution data, 

Mississippi Canyon 807, Proposed Locations A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, 

V, W, and X appear suitable for the planned activity. 

Kevin Bradford/ Larry Gibson Arlette C. Nunez 

Geophysicist/Geologist Shallow Hazard Interpreter 

B - F 

Pursuant to NTL No. 2008-G04 the proposed operations covered by this EP do not involve operations 

impacting the following: Topographic features map, Topographic features statement (shunting), Live 

bottoms, (Pinnacle Trend) map, Live bottoms (low relief) map, potentially sensitive biological features 

map. 

 
G. Remotely Operated Vehicle (ROV) Monitoring Plan

In accordance with the provisions of NTL 2008-G06, Remotely Operated Vehicle Surveys in Deepwater, 

Mississippi Canyon Block 807 is located in Grid 13. Grid 13 is an area that has adequate ROV survey 

coverage; therefore we are not proposing to run the pre- and post-ROV survey in accordance with the NTL. 

H. Threatened and Endangered Species Information

There are 5 species of sea turtles that may be found in the Gulf of Mexico (see table). No critical habitat for 

these species has been designated in the Gulf of Mexico. 

Common Name Scientific Name T/E Status

Hawksbill Turtle Eretmochelys imbricata E 

Green Turtle Chelonia mydas T 

Kemp's Ridley Turtle Lepidochelys kempii E 

Leatherback Turtle Dermochelys coriacea E 

Loggerhead Turtle Caretta caretta T 

There are 29 species of marine mammals that may be found in the Gulf of Mexico (see table). Of the species 

listed as Endangered, only the Sperm whale is commonly found in the project area. No critical habitat for these 

species has been designated in the Gulf of Mexico. 

Common Name Scientific Name T/E Status

Atlantic Spotted Dolphin Stenella frontalis 

Blainville's Beaked Whale Mesoplodon densirostris 

Blue Whale Balaenoptera musculus E 

Bottlenose Dolphin Tursiops truncatus 

Bryde's Whale Balaenoptera edeni 

Clymene Dolphin Stenella clymene 

Cuvier's Beaked Whale Ziphius cavirostris 

Dwarf Sperm Whale Kogia simus 

False Killer Whale Pseudorca crassidens 

Fin Whale Balaenoptera physalus E 

Fraser's Dolphin Lagenodelphis hosei 

Gervais' Beaked Whale Mesoplodon europaeus 

Humpback Whale Megaptera novaeangliae E 

Killer Whale Orcinus orca 

Melon-headed Whale Peponocephala electra 

Minke Whale Balaenoptera acutorostrata

Northern Right Whale Eubalaena glacialis E 

Pantropical Spotted Dolphin Stenella attenuata 

Pygmy Killer Whale Feresa attenuata 

Pygmy Sperm Whale Kogia breviceps 

Risso's Dolphin Grampus griseus 

Rough-toothed Dolphin Steno bredanensis 

Sei Whale Balaenoptera borealis E 

Short-finned Pilot Whale Globicephala macrorhynchus

Sowerby's Beaked Whale Mesoplodon bidens 

Sperm Whale Physeter macrocephalus E 

Spinner Dolphin (Long-snouted) Stenella longirostris 

Striped Dolphin Stenella coeruleoalba 

West Indian manatee Trichechus manatus E 
The EIA found in Attachment 18 discusses potential impacts and mitigation measures related to threatened and 

endangered species. 

I. Archaeological Report

Seafloor investigation is based on the C&C report number 083985-084126: Archaeological and Hazard 

Report, Blocks 762-763, 806-807, and Vicinity, Mississippi Canyon Area, dated June 2009. 

Archaeological Summary Statement

 

Data assessment for a multi-block survey encompassing Blocks 762, 763, 806, 807 and vicinity, 

Mississippi Canyon Area located 5637 unidentified sonar contacts. The seafloor pattern and acoustic 

characteristics of most of these targets suggest they could be “potential barrels” or other kinds of 

containers dumped in the study area by organized disposal operations. All of the sonar contacts are 

interpreted as modern debris associated primarily with industrial waste dumping or field development 

activities. These sonar contacts are not recommended for archaeological avoidance or investigation. 

Shell will comply with all conditions of NTL 2005-G07. 

J. Air and Water Quality Information

Pursuant to NTL 2008-G04 the proposed operations covered by this EP do not require Shell to 

provide additional information relating to air and water quality information. For specific information 

relating to air and water quality information please refer to the EIA, Attachment 18. 

K. Socioeconomic Information

Pursuant to NTL 2008-G04 the proposed operations covered by this EP do not require Shell to 

provide additional information relating to air and water quality information. For specific information 

relating to socioeconomic information please refer to the EIA, Attachment 18. 
Section 7: Waste and Discharge Information

A. Projected Generated Wastes

Note: Please specify if the amount reported is a total or per well amount Olympus 

Type of Waste and Composition Composition Projected Amount Discharge rate Discharge Method 

Will drilling occur ? If yes, you should list muds and cuttings

EXAMPLE: Cuttings wetted with ynthetic based fluid 

Cuttings generated while using synthetic 

based drilling fluid. X bbl/well X bbl/day discharge pipe 

Water-based drilling fluid barite, additives, mud 39,000 bbls / well 5,600 bbls / day

Overboard and seafloor discharge prior to 

marine riser installation 

Water-based drilling fluid barite, additives, mud 1,200 bbls / well 1,000 bbls / hr max discharge overboard (during pit clean outs

Cuttings wetted with water-based fluid

cuttings coated with water based drilling 

mud 2,555 bbls / well 365 bbls / hr max Sea bed during riserless drilling 

Cuttings wetted with synthetic-based fluid 

Cuttings generated while using synthetic based drilling fluid. 3,810 bbls / A well 17.8 bbls / day Overboard discharge below the water leve

Synthetic based drilling fluid adhering to washed drill cuttings

Synthetic based drilling fluid adhering to washed drill cuttings 1,714 bbls / A well 8 bbls / day Overboard discharge below the water leve

Chemical product waste 50 bbls / well 2 bbls / day

Treated to meet NPDES limits and discharged overboard 

Will humans be there? If yes, expect conventional waste

EXAMPLE: Sanitary waste water X liter/person/day NA chlorinate and discharge Domestic waste (kitchen water, shower water) grey water

 1,691 bbls / well

35,738 bbls / A well 

45 gal/person/day

167 bbls/day

Grinded to less than 25 mm mesh size and discharge overboard 

Sanitary waste (toilet water) treated sanitary waste

 1,124 bbls / well

23,754 bbls / A well 

30 gal/person/day

111 bbls/day

Treated in the MSD** prior to discharge to meet NPDES limits 

Is there a deck? If yes, there will be Deck Drainage

Deck Drainage Wash and rainwater

1,013 bbls / well

21,400 bbls / A well

100 bbls / day

(dependent on rainfall) Drained overboard through deck scuppers 

Will you conduct well treatment, completion, or workover? 

well treatment fluids NA NA NA NA 

well completion fluids NA NA NA NA workover fluids NA NA NA NA 

Miscellaneous discharges. If yes, only fill in those associated with your activity. 

Desalinization unit discharge Rejected water from watermaker unit

3,817 bbls / well

80,678 bbls / A well 377 bbls /day

Shunt through downpipe to below water's surface. 

Blowout prevent fluid Water based 856 bbls / well 4 bbls/day Disharge at seafloor 

Ballast water Uncontaminated seawater

1,013 bbls / well

21,400 bbls / A well 100 bbls / day

Shunt through downpipe to below water's surface. 

Bilge water

Bilge and drainage water will be treated to 

MARPOL standards (< 15ppm oil in water).

1,013 bbls / well

21,400 bbls / A well 100 bbls / day

Bilge and drainage water will be treated to 

MARPOL standards (< 15ppm oil in water)

Excess cement at seafloor Cement slurry

3,643 bbls/well (assume planned 100% excess is discharged) 3,643 bbls / well

Discharged at the seafloor during riserless drilling 

Fire water Treated seawater

142 bbls / well

2,996 bbls / A well 14 bbls / day Drained overboard through deck scuppers 

Cooling water Treated seawater

1,012,500 bbls / well

21,400,000 bbls / A well 100,000 bbls / day

Shunt through downpipe to below water's surface. 

Will you produce hydrocarbons? If yes fill in for produced water.

Produced water NA NA NA NA 

Will you be covered by an individual or general NPDES permit ? GENERAL PERMIT GMG290103NOTE: If you will not have a type of waste, enter NA in the row. 

TABLE 7A: WASTES YOU WILL GENERATE, TREAT AND DOWNHOLE DISPOSE OR DISCHARGE TO 

THE GOM

Projected generated waste Projected ocean discharges 
B. Projected Ocean Discharges

Olympus

Solid and Liquid Wastes 

transportation 

Type of Waste Composition Transport Method Name/Location of Facility Amount Disposal Method

Will drilling occur ? If yes, fill in the muds and cuttings.

EXAMPLE: Oil-based drilling fluid or mud NA NA NA NA NA

Oil-based drilling fluid or mud NA NA NA NA NA

Synthetic-based drilling fluid or mud used SBF and additives Drums on barges

Newpark Environmental Services 

(Fourchon, La.) or US Liquids of 

Louisiana (Fourchon, La.) 2,500 bbls/well Recycled

Cuttings wetted with Water-based fluid NA NA NA NA NA

Cuttings wetted with Synthetic-based fluid 

Drill cuttings from synthetic 

based interval. storage tank on supply boat.

Newpark Environmental Services 

(Fourchon, La.) or US Liquids of 

Louisiana (Fourchon, La.) 300 bbls / well Recycled

Cuttings wetted with oil-based fluids NA NA NA NA NA

Will you produce hydrocarbons? If yes fill in for produced sand.

Produced sand NA NA NA NA NA

EXAMPLE: trash and debris cardboard, aluminum, barged in a storage bin shorebase z tons total recycle

Trash and debris - recyclables trash and debris storage bins on supply boat

Omega Waste Management, W. 

Patterson, LA or ARC, New Iberia, LA 60 lbs/month recylce

Non-Hazardous trash and debris - nonrecyclables trash and debris storage bins on supply boatRepublic/BFI landfill, Sorrento, LA or 

the parish landfill, Avondale, LA. 118 lbs/month landfill

Hazardous waste

paints, solvents and unused 

chemicals drums on supply boat Safety Kleen, Denton, TX 60 lbs/month recylce

Used oil & glycole

used oil, oily rags and pads, 

empty drums and cooking 

oil drums on supply boat

Omega Waste Management, W. 

Patterson, LA or ARC, New Iberia, LA 20 bbls/month recycle

Universal waste items

Batteries, lamps, glass and 

mercury-contaminated 

waste drums on supply boat Lamp Environmental, Hammond, LA 30 bbls/month landfill

NOTE: If you will not have a type of waste, enter NA in the row. 

Waste Disposal

TABLE 7B: WASTES YOU WILL TRANSPORT AND /OR DISPOSE OF ONSHORE 

Will you have additional wastes that are not permitted for discharge? If 

yes, fill in the appropriate rows. 

Note: Please specify whether the amount reported is a total or per well

Projected generated waste

C. Modeling Report

Shell did not model the trajectory for discharges because it is not required in the GOM. 
Section 8: AIR EMISSIONS INFORMATION

A. Emissions Worksheet and Screening Questions 

Screening Questions for EP’s Yes No 

Is any calculated Complex Total (CT) Emission amount (in tons) associated with 

your proposed exploration activities more than 90% of the amounts calculated 

using the following formulas: CT = 3400D2/3 for CO, and CT 33.3D for the 

other air pollutants (where D distance to shore in miles)?

X 

Do your emission calculations include any emission reduction measures or 

modified emission factors? x 

Are your proposed exploration activities located east of 87.5° W longitude? x 

Do you expect to encounter H2S at concentrations greater than 20 parts per million 

(ppm)? x 

Do you propose to flare or vent natural gas for more than 48 continuous hours 

From any proposed well? x 

Do you propose to burn produced hydrocarbon liquids? x 

B. If you answer no to all of the above screening questions from the appropriate table, 

provide: 

(1) Summary information regarding the peak year emissions for both Plan Emissions and Complex 

Total Emissions, if applicable. This information is compiled on the summary form of the two 

sets of worksheets. You can submit either these summary forms or use the format below. You 

do not need to include the entire set of worksheets. 

Air Pollutant 

Plan 

Emission1 

Amounts 

(tons) 

Calculated 

Exemption2

Amounts 

(tons) 

Calculated 

Complex Total 

Emission 

Amounts3

(tons) 

PM 

SOx 

NOx 

VOC 

CO 

1

 For activities proposed in your EP or DOCD, list the projected emissions calculated from the 

worksheets. 

2

 List the exemption amounts for your proposed activities calculated by using the formulas in 30 CFR 

250.303(d). 

3

 List the complex total emissions associated with your proposed activities calculated from the 

worksheets 

 (2) Contact: Sylvia Bellone, (504) 728-7215, Sylvia.Bellone@shell.com

(1) Worksheets

See attached Modeling report prepared for this location. Also enclosed are model inputs and outputs on the 

attached CD. 

 
August 8, 2011 

 

Mr. Robert Kuehn 

Staff Environmental Engineer 

Shell Exploration and Production Company (EP-Americas) 

One Shell Square, OSS 3422 

New Orleans, LA 70161 

RE: OCD Modeling – Shell Mars B Well Batch Set, Exploration Plan, Mississippi 

Canyon Block 807 

Dear Mr. Kuehn: 

This letter report outlines the results of the Offshore and Coastal Dispersion (OCD) modeling for 

the proposed Mars B batch set drilling operations of the Shell Exploration and Production 

Company (Shell). The drilling will be located in Mississippi Canyon Block 807, at latitude 28° 9' 

35.59" (Universal Transverse Mercator (UTM) 3,116,942.13 meters North, Zone 16) and 

longitude 89° 14' 20.86" (UTM 280,137.86 meters East, Zone 16). 

The Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) has 

exemption criteria for offshore operations that are based on the projected highest annual 

emissions and the distance of the facility to the closest onshore area [30 CFR Part 250.303(d)]. 

Projected potential emissions from the well batch set operations at Mars B for particulate matter 

(PM), volatile organic compounds (VOC), carbon monoxide (CO), and sulfur dioxide (SO2) meet 

the exemption criteria of 30 CFR Part 250.303(d) for all years (2011 through 2013), therefore, no 

air quality modeling analysis is required for these pollutants. The projected potential emissions 

of nitrogen oxides (NOx) are above the exemption threshold for year 2012; therefore, an air 

quality modeling analysis has been performed for NOx. 

ESTIMATED EMISSIONS

Shell has estimated the potential annual emissions from emission sources associated with the well 

batch set operations at Mars B. The estimated potential annual emissions meet the BOEMRE 

exemption criteria for all pollutants except NOx. Details of the emissions exemption threshold 

analysis are presented in Appendix A. 

Potential emissions estimates for NOx were based on BOEMRE-approved emissions factors. 

Modeled emission rates (grams/second) were derived from the potential annual emission rate of 

each source for the annual and 1-hour averaging periods for NO2. Note that while the exemption 

criteria are based on NOx emissions, the modeled significance level (MSL) and the National 

Ambient Air Quality Standard (NAAQS) is dependent on emissions of nitrogen dioxide (NO2) 

[30 CFR Part 250.303(e)]. For conservatism, all emissions of NOx were assumed to be 

equivalent to NO2 for modeling purposes. Table 1 presents a summary of the potential-to-emit 

for each emission point. 

2800 Veterans Blvd., Suite 214 New Orleans, Louisiana 70002 U.S.A.  (504)828-5845  Fax (504) 828-7858 

Offices nationwide  trinityconsultants. c o m
Shell Mars B Batch Set EP OCD – Page 2 

August 8, 2011 

TABLE 1. SOURCE POTENTIAL TO EMIT1

Source Unit Model 

Input ID 

Model Input 

Emission Rate - 

LT/Annual 

(tpy) (g/s) 

Bully Rig 

20-710-GC Prime Mover 

 

573.07 16.49 

20-710-GC Prime Mover 573.07 16.49 

20-710-GC Prime Mover 573.07 16.49 

20-710-GC Prime Mover 573.07 16.49 

20-710-GC Prime Mover 573.07 16.49 

20-710-GC Prime Mover 573.07 16.49 

20-710-GC Prime Mover 573.07 16.49 

20-710-GC Prime Mover 573.07 16.49 

8-710-GC Emerg Gen 0.44 0.01 

Bully Rig Total Total Emissions from all sources on Bully BR 4584.97 131.89 

General Support 

Vessels 

General Support all years 280' OSV 1001.80 28.82 

General Support all years Crew Boat 191.02 5.50 

General 

Support Vessels 

Total 

Total Emissions from the general support 

vessels GV 1192.83 34.31 

Batch Support 

Vessels 

Batch set Support 2011/12 280' OSV 499.53 14.37 

Batch set Support 2011/12 370' OSV 635.00 18.27 

Batch Support 

Vessels Total Total Emissions from all batch support vessels BV 1134.53 32.64 

MODELING METHODOLOGY

Air Quality Model

The latest version of the OCD Model (Version 5.0, dated 05/16/2005) was used to assess the 

impacts of NOx emissions along the Louisiana and Mississippi shoreline. The objective of the 

analysis was to determine if the impacts from the well batch set drilling operations at Mars B 

would exceed modeling significance levels (MSLs) outlined in 30 CFR 250.303(e). 

On February 9, 2010,2 the U.S. Environmental Protection Agency (EPA) established a new 

1-hour National Ambient Air Quality Standard (NAAQS) for NO2. In that rulemaking, EPA 

established the 1-hour NO2 standard at a level of 100 ppb, based on the 3-year average of the 98th

 

1 Model input emission rates are based on emissions information provided by Mr. Robert Kuehn (Shell) via 

e-mail to Mr. Bill Bruscino (Trinity) sent on June 23, 2011. 

2 See 75 Fed. Reg. 6474 and 75 Fed. Reg. 35520. 
Shell Mars B Batch Set EP OCD – Page 3 

August 8, 2011 

percentile of the yearly distribution of 1-hour daily maximum concentrations. However, the final 

rules promulgating the 1-hour NO2 NAAQS did not include significance levels for the 1-hour 

averaging period. Therefore, on June 29, 2010, EPA proposed an interim 1-hour Significant 

Impact Level (SIL) of 4 ppb for NO2, for facilities to use as a screening tool for completing the 

required air quality analyses for the new 1-hour NO2 NAAQS under the Prevention of Significant 

Deterioration (PSD) program.3 This interim SIL is currently not included in 30 CFR 250.303(e). 

However, as BOEMRE has requested a comparison of the air emissions modeling analysis to the 

interim 1-hour NO2 SIL, Shell has assessed modeled impacts against the 1-hour NO2 interim SIL 

as well as the currently established annual NO2 SIL outlined in 30 CFR Part 250.303(e) .4

If the modeling analysis indicates that the interim NO2 1-hour SIL is exceeded, Shell will 

determine whether the emissions from the proposed activities combined with the nearest 

representative onshore NO2 monitor concentrations exceed the NO2 1-hour NAAQS.5 If the 

modeling analysis indicates that the emissions from the proposed activities combined with the 

nearest representative onshore NO2 monitor concentrations do not exceed the NAAQS, the 

emissions will not be deemed to significantly affect the air quality of an onshore area or a State, 

per 30 CFR 250.303(f). Hence, Shell would not be required by BOEMRE to adopt additional 

control measures under 30 CFR 250.303(h) (i.e., perform a Best Available Control Technology 

[BACT] Analysis).6 

Based on these requirements, the ambient modeled concentrations resulting from emissions 

generated from an offshore facility are compared to the SIL and NAAQS as shown in Table 2 

below. 

TABLE 2. APPLICABLE NAAQS AND SIGNIFICANT IMPACT LEVELS

Pollutant Averaging Period 

SIL 

(μg/m3

) 

NAAQS 

(μg/m3) 

NO2

Annual 1 100 

1-hour 7.5 188 

 

3 Based on U.S. EPA Memorandum from Stephen D. Page to Regional Air Division Directors titled, 

“Guidance Concerning the Implementation of the 1-hour NO2 NAAQS for the Prevention of Significant Deterioration 

Program,” June 29, 2010. 

4 Based on conversation between Ms. Holli Ensz (BOEMRE) and Mr. Bill Bruscino (Trinity) on 

March 7, 2011. 

5 Based on conversation between Mr. Dirk Herkhof (BOEMRE) and Mr. Bill Bruscino (Trinity) on 

March 31, 2011. 

6 Ibid. 
Shell Mars B Batch Set EP OCD – Page 4 

August 8, 2011 

Source Parameters and Emission Rates 

Shell estimated potential annual emissions from emission sources associated with the well batch 

set operations at Mars B. It was determined that NOx emissions from the proposed project’s 

operations in 2012 exceeded the exemption criteria of 30 CFR Part 250.303(d). Therefore, Shell 

has conducted air quality modeling analysis for potential NO2 emissions for 2012. Modeled 

emission rates in grams per second were derived from the annual emission rate of each source 

(tons per year) for the 1-hour and annual averaging periods.7

Per BOEMRE, emissions from the main emission units associated with the proposed operations 

may be combined with auxiliary emission units and modeled using the stack parameters of the 

main emission units.8 Given the relative proximity of emission sources to one another as 

compared to the distances to the onshore areas, and considering that the stack parameters for the 

largest emissions sources will be used as model inputs, the modeled impacts predicted using this 

approach are expected to be representative of the actual impacts from the proposed drilling 

operations on onshore areas. 

As per previous MMS guidance, support vessel emission sources may be co-located at the 

centroid of the operational area. Since Shell does not currently have stack parameter data specific 

to support vessels, and since the distance of the operational area from the shoreline is large 

relative to the distances in between the emission sources, Shell utilized a “pseudo-point” 

parameters approach in conservatively modeling operational activities for which actual stack 

parameters are not available, as previously approved by BOEMRE on similar modeling projects: 

• Source location: 

o Latitude= 28o

 09’ 35.59” North 

o Longitude= 89o

 14’ 20.86” West 

• Stack Velocity9 = 0.001 m/s 

• Stack Diameter10 = 0.001 m 

• Stack Exit Temperature 11 = 500° F 

 

7 Based on conversation between Ms. Holli Ensz (BOEMRE) and Mr. Bill Bruscino (Trinity) on March 7, 

2011, BOEMRE is requesting that applicants supply the 1-hour modeling results obtained from the annual NO2

modeling analysis. Based on this guidance, the annual and 1-hour NO2 modeling analysis results would be based on 

the annual average emission rate for each emission source. 

8 Based on phone conversation between Ms. Holli Ensz (BOEMRE) and Trinity on January 4, 2011 

9 The stack velocity and stack diameter are based on previous guidance provided by BOEMRE and represent 

the guidance provided typically by state air regulatory agencies (e.g. Texas Commission on Environmental Quality 

[TCEQ]) for modeling fugitive sources in a representative manner by limiting the influence of stack-tip downwash. 

10 Ibid. 

11 Since all NOx-emitting sources are combustion-related, Shell proposes a conservative exit temperature of 

500° F to account for buoyancy-induced dispersion. 
Shell Mars B Batch Set EP OCD – Page 5 

August 8, 2011 

For emission sources other than the support vessels, the air quality modeling was based on 

source-specific stack parameter data. The emission point modeled source parameters for all the 

sources are presented in Table 3. 

TABLE 3. MODEL INPUT STACK PARAMETERS

Source Name 12 OCD 

ID 

OCD X - 

Coordinates 

OCD Y - 

Coordinates 

Stack 

Height 

Stack 

Gas 

Temp 

Stack 

Diameter 

Stack 

Exit 

Vel 

Dev of 

Stack 

Angle 

 km km m K m m/s degrees 

Bully Rig BR 510.094 299.574 23.5 576 0.76 18.71 0.00 

General Support 

Vessels GV 510.094 299.574 3.61 533 0.001 0.001 0.00 

Batch Support 

Vessels BV 510.094 299.574 7.73 533 0.001 0.001 0.00 

 

12 The stack parameters were sent via file upload by Mr. Robert Kuehn (Shell) to Trinity on February 28, 

2011. The stack parameters for the Bully Rig are based on the stack parameters for the Main Engines No. 1 to 4 and 7. 
See Figure 1-2

See Figure 1-3

= Recep= Mars B

Figure 1-1. AREA MAP – RECEPTOR LOCATIONS

Shell Offshore, Inc.

Mars B Batch Set – Mississippi Canyon
Figure 1-2. AREA MAP – RECEPTOR LOCATIONS

Shell Offshore, Inc.

Mars B Batch Set – Mississippi Canyon
Figure 1-3. AREA MAP - RECEPTOR LOCATIONS

Shell Offshore, Inc.

Mars B Batch Set – Mississippi Canyon
Shell Mars B Batch Set EP OCD – Page 9 

August 8, 2011 

Meteorological Data

The OCD model requires both over-land and over-water meteorological data. The following 

meteorological datasets were used for the air quality modeling analyses to determine the potential 

impacts of the well batch set operations at Mars B on onshore receptors: 

• Water temperature, over-water air temperature, over-water dew point temperature, overwater wind speed, and over-water wind direction from Station 42040 – Luke Offshore 

Test Platform, an off-shore buoy operated by the National Data Buoy Center (NDBC). 

• Over-land surface observations of key meteorological variables from the Patterson 

National Weather Service (NWS) station. 

• Upper air observations of key meteorological variables from the Slidell NWS station. 

The above data sources were selected for this analysis because: 

• Station 42040 is located at a distance of 95.69 miles from the location of the well batch 

set operations. While data is available from NDBC for other stations located relatively 

closer to the location of the proposed operations, it is proposed to use the data from 

Station 42040 as it is most complete and representative of the over-water conditions that 

prevail at the location of the proposed operations. For example Station BURL1 is located 

closest to the proposed location of the proposed operations at a distance of 52.82 miles. 

However, this station is almost at the edge of the Mississippi River delta and due to its 

proximity to land, the data from it will not be as representative of the over-water 

conditions that prevail at the location of the proposed operations as Station 42040. 

Similarly other offshore NDBC stations located relatively closer to the proposed location 

of the well batch set operations do not have complete, representative, or recent years data 

available (2000 onwards). 

• Slidell (LA) NWS station is the closest upper air meteorological station providing 

reliable data. 

• Patterson (LA) NWS is the closest surface meteorological station providing reliable data. 

The data sources presented above have been selected in accordance with MMS guidance, as 

provided in the Five-Year Meteorological Datasets for CALMET/CALPUFF and OCD5 

Modeling of the Gulf of Mexico Region (July 2008).13 According to Section 4.1 of the 

document, OCD Group 5a is required to utilize over-water data from Buoy 42040, surface 

onshore data from the Patterson NWS station, and upper-air data from Slidell NWS station. 

Since the location of the proposed well batch set operations qualifies as part of OCD Group 

5a, Shell is justified in using the described meteorological data. 

Shell used meteorological data for five consecutive years, 2000, 2001, 2002, 2003 and 2004 in 

this air quality modeling analysis. The over-water and over-land meteorological datasets for the 

stations proposed above for these five years were found to be most complete in order to complete 

 

13 Five-Year Meteorological Datasets for CALMET/CALPUFF and OCD5 Modeling of the Gulf of Mexico Region, 

U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region (July 2008). 
Shell Mars B Batch Set EP OCD – Page 10 

August 8, 2011 

the modeling analysis based on the modeling protocol submitted by Shell previously for a similar 

modeling project to BOEMRE/MMS. Model runs were performed using over-water mixing 

heights of 300, 600, and 900 meters for each of the five years, as per BOEMRE guidance on 

previous similar modeling projects. Over-land meteorological data was processed using the U.S. 

EPA’s Meteorological Preprocessor for Regulatory Models (MPRM). Missing elements in the 

datasets were accounted for using EPA-recommended procedures.14 Several methods were used 

to replace missing over-water data. Linear interpolation was used to obtain missing wind speed 

values. A unit vector average was used to substitute for a single missing wind direction value. 

Two- to ten-hour periods of missing wind speed and direction data were subjectively filled based 

on the persistent weather pattern in the surrounding area. Meteorological data files are included 

as Attachment B in electronic format (attached CD). 

Receptor Locations and Land-Mass Configuration

A series of 100 discrete receptors spaced three miles apart were placed along the Louisiana and 

Mississippi (Gulf Coast) shorelines closest to the location of the well batch set operations. 

Additionally, two receptors were placed in the Breton Wilderness Area (Louisiana) and five 

receptors were placed on Chandeleur Islands (located within the Breton Wilderness Area) in 

order to assess impacts on federal Class 1 Areas. This is consistent with previous guidance 

provided by BOEMRE for similar modeling projects for offshore operations. 

MODEL OPTIONS

The OCD model options are listed in the modeling input file (included on the CD in Attachment 

B). All sources modeled in this analysis are considered to be point sources. Because the Gulf 

Coast area of concern is situated at sea level, no terrain features were considered (i.e., simple 

terrain only). 

MODELING RESULTS

The following section details the results of the air quality modeling. A review of the OCD 

modeling results indicates that the well batch set operations at Mars B do not exceed the 

significant impact level for the annual averaging period for NO2. The results for the Breton 

Wilderness Class I area (Breton) receptors also demonstrate that the Mars B Well Batch Set 

operations do not exceed the Modeling Significance Level (MSL) or the Class I PSD Increment 

for the annual NO2 standard. However, the maximum modeled concentrations exceed the 

respective significant impact level for the 1-hour averaging period for NO2 for the Breton 

receptors as well as for the entire region. 

The results also indicate that the maximum modeled concentrations for the 1-hour averaging 

period for NO2 combined with the nearest representative onshore NO2 monitor concentrations do 

not exceed the NO2 1-hour NAAQS for the Breton receptors as well as the entire region. 

 

14 Missing Data Procedures for Substituting Values for Missing NWS Meteorological Data for Use in 

Regulatory Air Quality Models, EPA SCRAM, July 7, 1992. 
Shell Mars B Batch Set EP OCD – Page 11 

August 8, 2011 

Table 4 presents the summarized results of the three-year average of the 98% of the daily 

maximum concentration of NO2 monitored at the Kenner monitoring station. Kenner is the 

closest station to the receptor set with representative monitoring data. 

TABLE 4. MONITORING STATION DATA15

98% Daily Max ppm (μg/m3

) 

2007 0.055 103.48 

2008 0.048 90.31 

2009 0.048 90.31 

Average 0.050 94.70 

Table 5 presents the summarized results from the modeling analysis performed for the well batch 

set operations at Mars B for the Breton Wilderness Class I area. Table 6 presents the summarized 

results for the entire modeled region. OCD modeling output files are included as Attachment B 

in electronic format (attached CD). A concentration table containing results for each receptor 

from each model run is presented as Attachment C. Attachment D contains concentration table 

results specifically for each receptor in the Breton Wilderness Class I area. 

TABLE 5. MAXIMUM MODELED CONCENTRATIONS FOR ALL BRETON RECEPTORS

Pollutant Averaging 

Period 

Maximum 

Modeled 

Concentration 

(μg/m3

) 

Modeling 

Significance 

Level 

(μg/m3) 

Significant? 

Class I 

PSD 

Increment 

(μg/m3

) 

Is Model 

over PSD 

Increment 

level? 

98% 

Daily 

Max 

(3-yr avg) 

(μg/m3

) 

Combined 

Concentration 

(μg/m3

) 

NAAQS 

(μg/m3

) 

Exceed 

NAAQS 

NO2

Annual 0.35 1 No 2.5 No

94.70 

-- 100 No 

1-hr 39.91 7.5 Yes -- -- 134.61 188 No 

Since the modeled annual NO2 concentrations for the Breton Wilderness Class I area are less than 

the significant impact level for the NO2 annual averaging period, no further action standard. 

Additionally, for the modeled hourly NO2 concentrations, when combined with an appropriate 

background monitored value, are below the NO2 1-hour-NAAQS, no further action is required. 

 

15 Monitoring station data was obtained from the Louisiana Department of Environmental Quality website 

for the most recent 3 years for hourly concentrations of NO2. 
Shell Mars B Batch Set EP OCD – Page 12 

August 8, 2011 

TABLE 6. MAXIMUM MODELED CONCENTRATIONS FOR THE ENTIRE REGION

Pollutant Averaging 

Period Receptors 

Maximum 

Modeled 

Concentration 

(μg/m3

) 

Modeling 

Significance 

Level 

(μg/m3

) 

Significant?

98% 

Daily 

Max 

(3 year 

average) 

(μg/m3

) 

Combined 

Concentration 

(μg/m3

) 

NAAQS 

(μg/m3

) 

NAAQS 

Exceeded?

NO2

Annual 1 through 

107 0.54 1.0 No N/A -- 100 No 

1-Hour 1 through 

107 68.84 7.5 Yes 94.70 163.54 188 No 

Since the modeled annual NO2 concentrations for the entire region are less than the significant 

impact level for the NO2 annual averaging period, no further action is required. Additionally, for 

modeled hourly NO2 concentrations, when combined with an appropriate background monitored 

value, are below the NO2 1-hour-NAAQS, no further action is required. 

Thank you for the opportunity to provide this evaluation. Please feel free to call me at 

(504) 828-5845 with any questions or comments. 

Sincerely, 

TRINITY CONSULTANTS 

Sharon Killian 

Principal Consultant 

Enclosures 

cc: Ms. Sylvia Bellone (Shell) 
ATTACHMENT A: SOURCE DOCUMENTATION

Emissions Calculations and Threshold Limit Evaluation 

 
COMPANY Shell Offshore Inc

AREA MC BLOCK 807LEASE OCS-G 7963 PLATFORM Olympus Batch Set and MB01 PredrillWELL A through X

COMPANY CONTACT Sylvia Bellone

TELEPHONE NO. 5047287215REMARKS Bully 1 RigLEASE TERM PIPELINE CONSTRUCTION INFORMATION:

YEAR NUMBER OF TOTAL NUMBER OF CONSTRUCTION DAYS

PIPELINES

20102011201220132014201520162017201820192020
Fuel Usage Conversion Factors Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine RE

SCF/hp-hr 9.524 SCF/hp-hr 7.143 GAL/hp-hr 0.0483 AP42 

Equipment/Emission Factors units PM SOx NOx VOC CO RE

NG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3.2

NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP42 NG 4-cycle lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP42 NG 4-cycle rich gms/hp-hr 0.00185 10 0.14 8.6 AP42 

Diesel Recip. < 600 hp. gms/hp-hr 1 0.1835 14 1.12 3.03 AP42 

Diesel Recip. > 600 hp. gms/hp-hr 0.32 0.1835 11 0.33 2.4 AP42 Diesel Boiler lbs/bbl 0.084 0.3025 0.84 0.008 0.21 AP42 1NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 AP42 1.4-1, NG Flares lbs/mmscf 0.593 71.4 60.3 388.5 AP42 Liquid Flaring lbs/bbl 0.42 6.83 2 0.01 0.21 AP42 1.3Tank Vapors lbs/bbl 0.03 E&P Fugitives lbs/hr/comp. 0.0005 API SGlycol Dehydrator Vent lbs/mmscf 6.6 La. Gas Venting lbs/scf 0.0034

Sulfur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.05 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

Diesel fuel intended for locomotive, marine and non-road engines and equipment is requireDiesel fuel maximum specification of 500 ppm sulfur in 2007, per EPA regulation. Diesel fuavailable. http://www.clean-diesel.org/nonroad.html
Schedule

Batch set wells 24MB01 well deepening 1Event Duration 2011 Duration 2012 Duration 2013Bully batch set 2011 60 0 0

Bully usage 2012 batch and well deepening

0 365 0

Bully well deepening 2013 00 60

Many cells are linked or are used as links in other sheets- change cell contents OR add/delete rows/columns wit

Basis for various estimates Used in this AQR

ADF9762.msg 8224683B.msg
Many cells are linked or are used as links in other sheets- change cell contents OR add/delete rows/columns wit

Basis for various estimates Used in this AQR

Note: 8/23/11- revisd 2013 days to 60 (from 30) to account for possible delays in schedule.

Support vessels

base info per email fom Brad Landreth, Sr Stf Logistics Specialist 4/20/11Event Vessel HP umber of Vess %Load hr/d Comments

General Support all years 280' OSV 9440 1 100% 24

Assume 100% load due to short duration usage in 2011

General Support all years Crew Boat 5400 1 100% 8

Assume 100% load due to short duration usage in 2011. On average crew vessels will be within 25 miles 30% of time. To model this set hr/d=8.

Batch set Support 2011/12 370' OSV 12000 1 100% 24

Assume 100% load due to short duration usage in 2011

Batch set Support 2011/12 280' OSV 9440 1 100% 24

Assume 100% load due to short duration usage in 2011

182

Miscellaneous basis

Bully Sources

- 8 main engines rated at 5400 HP (nameplate)- One emergency generator at 2150 HP (nameplate). Operated for 3 hr/month for testing- All other equipment is electric (e.g cement units, logging units, cranes) or negligable in emissions potential (e.g. life boats)

Above info for Bully from Shell April 2010 PSD and Title V Permit Application to USEPA Region 4Note- batch set support vessels will not be utilized during entire batch set in 2012. They will only be used for shown days ---------------------------------------------------------------------------------->
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc MC 807 OCS-G 7963 Olympus Batch Set and MB01 Predrill A through X Sylvia Bellone 5047287215 Bully 1 Rig

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLINGBully 1 All Operating Modes 20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 

20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 

20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 

20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 

20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 

20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 

20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 

20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 

8-710-GC Emerg Gen 2150 103.845 2492.28 3 2 1.52 0.87 52.09 1.56 11.37 0.00 

All other equipment is electric (e.g cranes) or negligable in emissions potential (e.g. life boats)General Support 2011 280' OSV 9440 455.952 10942.85 24 60 6.65 3.82 228.72 6.86 49.90 4.79 

General Support 2011 Crew Boat 5400 260.82 6259.68 8 60 3.81 2.18 130.84 3.93 28.55 0.91 

Batch set Support 2011 370' OSV 12000 579.6 13910.40 24 60 8.46 4.85 290.75 8.72 63.44 6.09 

Batch set Support 2011 280' OSV 9440 455.952 10942.85 24 60 6.65 3.82 228.72 6.86 49.90 4.79 

2011 YEAR TOTAL 57.54 32.99 1977.82 59.33 431.52 38.51 

EXEMPTION CALCULATION DISTANCE FROM LAND IN MILES 1931.40 

58.0

Support Vessels
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc MC 807 OCS-G 7963 Olympus Batch Set and MB01 Predrill A through X Sylvia Bellone 5047287215 Bully 1 Rig

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

DRILLING Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

Bully 1 All Operating Modes 20-710-GC Prime Mover 5400 260.82 6259.68 24 365 3.81 2.18 130.84 3.93 28.55 16.67 

20-710-GC Prime Mover 5400 260.82 6259.68 24 365 3.81 2.18 130.84 3.93 28.55 16.67 

20-710-GC Prime Mover 5400 260.82 6259.68 24 365 3.81 2.18 130.84 3.93 28.55 16.67 

20-710-GC Prime Mover 5400 260.82 6259.68 24 365 3.81 2.18 130.84 3.93 28.55 16.67 

20-710-GC Prime Mover 5400 260.82 6259.68 24 365 3.81 2.18 130.84 3.93 28.55 16.67 

20-710-GC Prime Mover 5400 260.82 6259.68 24 365 3.81 2.18 130.84 3.93 28.55 16.67 

20-710-GC Prime Mover 5400 260.82 6259.68 24 365 3.81 2.18 130.84 3.93 28.55 16.67 

20-710-GC Prime Mover 5400 260.82 6259.68 24 365 3.81 2.18 130.84 3.93 28.55 16.67 

8-710-GC Emerg Gen 2000 96.6 2318.40 3 6 1.41 0.81 48.46 1.45 10.57 0.01 

All other equipment is electric (e.g cranes) or negligable in emissions potential (e.g. life boats)Batch set Support 2011/12 280' OSV 9440 455.952 10942.85 24 182 6.65 3.82 228.72 6.86 49.90 14.53 

Gerneral Support all years 280' OSV 9440 455.952 10942.85 24 365 6.65 3.82 228.72 6.86 49.90 29.14 

General Support all years Crew Boat 5400 260.82 6259.68 8 365 3.81 2.18 130.84 3.93 28.55 5.56 Batch set Support 2011/12 370' OSV 12000 579.6 13910.40 24 182 8.46 4.85 290.75 8.72 63.44 18.47 

2012 YEAR TOTAL 57.43 32.93 1974.19 59.23 430.73 201.0

EXEMPTION CALCULATION DISTANCE FROM LAND IN MILES 1931.4

58.0

Support Vessels
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc MC 807 OCS-G 7963 Batch Set and MBA through X Sylvia Bellone 5047287215 Bully 1 Rig

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM SO

DRILLINGBully 1 All Operating Modes 20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 1.5

20-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 1.520-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 1.520-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 1.520-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 1.520-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 1.520-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 1.520-710-GC Prime Mover 5400 260.82 6259.68 24 60 3.81 2.18 130.84 3.93 28.55 2.74 1.58-710-GC Emerg Gen 2150 103.845 2492.28 3 2 1.52 0.87 52.09 1.56 11.37 0.00 0.0All other equipment is electric (e.g cranes) or negligable in emissions potential (e.g. life boats)General Support all years 280' OSV 9440 455.952 10942.85 24 60 6.65 3.82 228.72 6.86 49.90 4.79 2.7

General Support all years Crew Boat 5400 260.82 6259.68 8 60 3.81 2.18 130.84 3.93 28.55 0.91 0.5

2013 YEAR TOTAL 42.42 24.33 1458.35 43.75 318.19 27.63 15.

EXEMPTION CALCULATION DISTANCE FROM LAND IN MILES 1931.40 1931

58.0

many cells are linked or are used as links in other sheets- change with caution!Support Vessels
COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore Inc MC 807 OCS-G 7963 Olympus Batch Set anA through X

Emitted Substance

Year TPY

 PM SOx NOx VOC CO

2011 38.51 22.08 1323.88 39.72 288.85

2012 201.09 115.31 6912.32 207.37 1508.142013 27.63 15.85 949.86 28.50 207.24

Allowable 1931.40 1931.40 1931.40 1931.40 50944.53
ATTACHMENT B: OCD MODELING FILES

Provided Electronically on Attached CD 
ATTACHMENT C: MODELING RESULTS FOR THE ENTIRE REGION
Table C-1. Shell Offshore, Inc. - OCD Modeling Results

Mars B Batch Exploration Plan - Mississippi Canyon

300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 900 m

B1+

29.4851 -89.1701 0.29 0.17 0.14 0.22 0.13 0.11 0.35 0.2 0.16 0.3 0.19 0.16 0.25 0.15 0.12

B2+

29.4623 -89.2030 0.3 0.17 0.14 0.22 0.13 0.11 0.35 0.2 0.17 0.3 0.19 0.16 0.26 0.15 0.12

C1+

29.9088 -88.8219 0.16 0.09 0.07 0.14 0.08 0.07 0.17 0.1 0.08 0.13 0.08 0.06 0.15 0.08 0.07

C2+

29.9524 -88.8261 0.16 0.08 0.07 0.14 0.08 0.06 0.17 0.1 0.08 0.13 0.08 0.06 0.14 0.08 0.07

C3+

29.8669 -88.8371 0.16 0.09 0.07 0.15 0.08 0.07 0.18 0.1 0.08 0.13 0.08 0.07 0.15 0.09 0.07

C4+

29.8345 -88.8373 0.16 0.09 0.07 0.15 0.08 0.07 0.18 0.1 0.08 0.14 0.08 0.07 0.15 0.09 0.07

C5+

29.7925 -88.8604 0.17 0.09 0.08 0.16 0.09 0.07 0.19 0.11 0.09 0.14 0.09 0.07 0.16 0.09 0.07

R1 29.0003 -89.3673 0.39 0.24 0.22 0.32 0.2 0.18 0.41 0.26 0.23 0.33 0.22 0.2 0.36 0.23 0.2

R10 29.0048 -89.1778 0.45 0.28 0.24 0.35 0.23 0.2 * 0.54 * 0.33 * 0.29 * 0.49 * 0.32 * 0.29 0.4 0.24 0.21

R11 28.9900 -89.1422 0.4 0.25 0.22 0.38 0.25 0.22 0.49 0.31 0.27 0.47 0.32 0.28 0.39 0.24 0.2

R12 29.0749 -89.1185 0.35 0.21 0.19 0.35 0.22 0.2 0.43 0.26 0.23 0.41 0.27 0.24 0.34 0.21 0.17

R13 29.0528 -89.1568 0.4 0.25 0.21 0.34 0.21 0.19 0.49 0.3 0.26 0.46 0.3 0.27 0.37 0.22 0.19

R14 29.0887 -89.0727 0.32 0.2 0.18 0.32 0.2 0.18 0.36 0.22 0.19 0.33 0.21 0.19 0.3 0.19 0.16

R15 29.1338 -89.0453 0.3 0.19 0.16 0.29 0.18 0.16 0.32 0.2 0.17 0.28 0.18 0.16 0.28 0.17 0.15

R16 29.1791 -89.0052 0.28 0.17 0.15 0.25 0.15 0.14 0.3 0.18 0.16 0.23 0.15 0.13 0.25 0.16 0.14

R17 29.2150 -89.0270 0.28 0.17 0.15 0.26 0.16 0.14 0.29 0.18 0.15 0.25 0.16 0.14 0.25 0.15 0.13

R18 29.2967 -89.1575 0.33 0.19 0.16 0.26 0.15 0.13 0.4 0.23 0.2 0.36 0.23 0.2 0.29 0.17 0.14

R19 29.3382 -89.1836 0.33 0.19 0.16 0.24 0.14 0.13 0.39 0.23 0.19 0.34 0.22 0.19 0.29 0.17 0.14

R2 28.9636 -89.4025 0.4 0.26 0.23 0.37 0.23 0.21 0.43 0.27 0.25 0.37 0.25 0.23 0.37 0.24 0.22

R20 29.3495 -89.2666 0.32 0.19 0.16 0.25 0.15 0.13 0.36 0.21 0.18 0.31 0.19 0.16 0.29 0.17 0.14

R21 29.3881 -89.3120 0.31 0.18 0.15 0.25 0.14 0.12 0.33 0.19 0.16 0.29 0.17 0.15 0.27 0.16 0.13

R22 29.2529 -89.1174 0.31 0.18 0.16 0.28 0.17 0.15 0.38 0.23 0.2 0.36 0.23 0.2 0.29 0.17 0.14

R23 29.7637 -89.2865 0.24 0.13 0.11 0.19 0.1 0.08 0.26 0.15 0.12 0.23 0.14 0.11 0.21 0.12 0.09

R24 29.0430 -89.3525 0.38 0.24 0.21 0.31 0.19 0.17 0.41 0.25 0.22 0.32 0.21 0.19 0.35 0.22 0.19

R25 30.3367 -89.1708 0.18 0.1 0.07 0.13 0.07 0.06 0.21 0.11 0.09 0.18 0.11 0.09 0.16 0.08 0.06

R26 29.0826 -89.3137 0.4 0.25 0.22 0.33 0.2 0.18 0.43 0.26 0.22 0.36 0.23 0.2 0.36 0.22 0.19

R27 29.1272 -89.3603 0.35 0.21 0.19 0.28 0.17 0.15 0.38 0.23 0.2 0.3 0.19 0.17 0.32 0.2 0.17

R28 29.1564 -89.3973 0.32 0.2 0.17 0.27 0.16 0.14 0.35 0.21 0.18 0.28 0.18 0.16 0.3 0.19 0.16

R29 29.1875 -89.4501 0.14 0.14 0.14 0.13 0.13 0.13 0.16 0.16 0.16 0.14 0.14 0.14 0.14 0.14 0.14

R3 28.9287 -89.4210 0.44 0.29 0.26 0.4 0.26 0.24 0.46 0.29 0.26 0.4 0.28 0.25 0.37 0.25 0.23

R30 30.3560 -89.1167 0.18 0.09 0.07 0.13 0.07 0.06 0.21 0.11 0.09 0.18 0.11 0.09 0.15 0.08 0.06

R31 29.2342 -89.4950 0.14 0.14 0.14 0.13 0.13 0.13 0.15 0.14 0.14 0.14 0.14 0.14 0.13 0.13 0.13

R32 29.2424 -89.5571 0.32 0.19 0.17 0.28 0.17 0.15 0.32 0.19 0.17 0.27 0.17 0.16 0.25 0.16 0.14

R33 29.2544 -89.6062 0.32 0.19 0.16 0.27 0.17 0.15 0.31 0.19 0.16 0.26 0.17 0.15 0.25 0.16 0.14

R34 29.2838 -89.6352 0.31 0.18 0.16 0.27 0.16 0.14 0.3 0.18 0.16 0.25 0.16 0.14 0.24 0.15 0.13

R35 29.2950 -89.6813 0.3 0.17 0.15 0.26 0.16 0.14 0.29 0.17 0.15 0.25 0.16 0.14 0.23 0.14 0.13

R36 29.3057 -89.7325 0.28 0.16 0.14 0.25 0.15 0.13 0.27 0.16 0.14 0.24 0.15 0.14 0.23 0.14 0.13

R37 29.3129 -89.7805 0.27 0.16 0.14 0.23 0.14 0.13 0.26 0.16 0.14 0.24 0.15 0.14 0.23 0.14 0.12

R38 29.3192 -89.8416 0.26 0.15 0.13 0.22 0.13 0.12 0.28 0.16 0.14 0.22 0.14 0.13 0.24 0.14 0.12

R39 29.3063 -89.8803 0.25 0.15 0.13 0.22 0.14 0.12 0.3 0.18 0.16 0.22 0.14 0.12 0.25 0.15 0.13

R4 28.9530 -89.3799 0.4 0.26 0.23 0.35 0.22 0.2 0.43 0.28 0.25 0.36 0.24 0.22 0.38 0.25 0.22

R40 29.2830 -89.9251 0.24 0.14 0.12 0.24 0.14 0.13 0.33 0.2 0.17 0.22 0.14 0.12 0.26 0.15 0.13

R41 30.2407 -88.7347 0.13 0.07 0.06 0.12 0.07 0.05 0.15 0.08 0.06 0.11 0.06 0.05 0.12 0.07 0.05

R42 30.2334 -88.6836 0.12 0.07 0.05 0.12 0.06 0.05 0.15 0.08 0.06 0.1 0.06 0.05 0.12 0.07 0.06

R43 30.2264 -88.6337 0.12 0.06 0.05 0.12 0.06 0.05 0.15 0.08 0.06 0.1 0.06 0.05 0.12 0.07 0.06

R44 30.2123 -88.5057 0.12 0.06 0.05 0.12 0.06 0.05 0.13 0.07 0.05 0.1 0.06 0.05 0.11 0.06 0.05

R45 30.1981 -88.4514 0.12 0.07 0.05 0.12 0.06 0.05 0.12 0.06 0.05 0.11 0.06 0.05 0.1 0.06 0.05

R46 30.2287 -88.3314 0.12 0.06 0.05 0.12 0.06 0.05 0.11 0.06 0.04 0.1 0.06 0.05 0.09 0.05 0.04

R47 30.2334 -88.2799 0.11 0.06 0.05 0.12 0.06 0.05 0.11 0.06 0.04 0.1 0.06 0.05 0.09 0.05 0.04

R48 30.2426 -88.2289 0.1 0.06 0.04 0.11 0.06 0.05 0.1 0.06 0.04 0.1 0.06 0.05 0.09 0.05 0.04

R49 30.2490 -88.1776 0.1 0.05 0.04 0.11 0.06 0.04 0.1 0.05 0.04 0.1 0.06 0.04 0.09 0.05 0.04

R5 28.9880 -89.3502 0.4 0.26 0.23 0.32 0.2 0.18 0.43 0.27 0.24 0.34 0.23 0.2 0.37 0.24 0.21

R50 30.2429 -88.1249 0.09 0.05 0.04 0.1 0.05 0.04 0.09 0.05 0.04 0.09 0.05 0.04 0.09 0.05 0.04

R51 30.2179 -88.0981 0.09 0.05 0.04 0.1 0.05 0.04 0.09 0.05 0.04 0.09 0.05 0.04 0.1 0.05 0.04

R52 30.2254 -88.0262 0.09 0.05 0.04 0.1 0.05 0.04 0.08 0.05 0.03 0.08 0.05 0.04 0.1 0.06 0.04

R53 30.2295 -87.9749 0.09 0.05 0.04 0.09 0.05 0.04 0.08 0.04 0.03 0.08 0.05 0.04 0.1 0.06 0.04

R54 30.2312 -87.9224 0.09 0.05 0.04 0.09 0.05 0.04 0.08 0.04 0.03 0.08 0.05 0.04 0.1 0.06 0.05

R55 30.2293 -87.8697 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.07 0.04 0.04 0.1 0.06 0.04

R56 30.3789 -89.0398 0.16 0.09 0.07 0.13 0.07 0.06 0.2 0.11 0.09 0.18 0.11 0.09 0.15 0.08 0.06

R57 30.3905 -88.9739 0.15 0.08 0.06 0.14 0.07 0.06 0.18 0.1 0.08 0.17 0.11 0.09 0.14 0.08 0.06

R58 30.0506 -89.1956 0.21 0.11 0.09 0.15 0.08 0.07 0.24 0.13 0.1 0.21 0.12 0.1 0.18 0.1 0.08

R59 30.2497 -87.6604 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.08 0.04 0.04 0.09 0.05 0.04

R6 29.0187 -89.3147 0.43 0.27 0.24 0.35 0.22 0.19 0.45 0.28 0.24 0.38 0.25 0.22 0.38 0.24 0.21

R60 29.0452 -90.7606 0.18 0.11 0.09 0.17 0.1 0.08 0.23 0.13 0.12 0.19 0.12 0.1 0.21 0.12 0.1

R61 29.0549 -90.7036 0.18 0.11 0.1 0.17 0.1 0.09 0.24 0.14 0.12 0.21 0.13 0.11 0.21 0.12 0.1

R62 29.0891 -90.5456 0.18 0.11 0.1 0.18 0.11 0.09 0.28 0.16 0.14 0.23 0.14 0.13 0.23 0.13 0.11

R63 29.0584 -90.4559 0.19 0.12 0.11 0.19 0.12 0.1 0.31 0.18 0.15 0.24 0.15 0.14 0.24 0.14 0.12

R64 29.0659 -90.3210 0.23 0.14 0.13 0.22 0.13 0.12 0.33 0.19 0.17 0.24 0.16 0.14 0.24 0.14 0.12

R65 29.0860 -90.2228 0.24 0.15 0.14 0.24 0.15 0.13 0.33 0.2 0.18 0.25 0.16 0.14 0.24 0.14 0.12

R66 29.1089 -90.1794 0.24 0.15 0.14 0.25 0.15 0.13 0.34 0.21 0.19 0.25 0.16 0.14 0.24 0.14 0.12

R67 29.1330 -90.1383 0.25 0.15 0.14 0.25 0.15 0.13 0.35 0.21 0.19 0.25 0.16 0.14 0.25 0.15 0.12

R68 29.1598 -90.0977 0.26 0.16 0.14 0.25 0.15 0.13 0.34 0.21 0.19 0.25 0.16 0.14 0.26 0.15 0.13

R69 29.1867 -90.0546 0.26 0.16 0.14 0.25 0.15 0.13 0.34 0.21 0.18 0.25 0.16 0.14 0.27 0.16 0.13

R7 29.0549 -89.2832 0.43 0.27 0.23 0.35 0.22 0.19 0.46 0.28 0.24 0.4 0.26 0.22 0.38 0.23 0.2

R70 29.2253 -90.0056 0.24 0.15 0.13 0.25 0.15 0.13 0.34 0.21 0.18 0.23 0.15 0.13 0.27 0.16 0.13

R71 29.2511 -89.9598 0.24 0.14 0.12 0.25 0.15 0.13 0.35 0.21 0.19 0.22 0.14 0.13 0.27 0.16 0.13

R72 30.3605 -88.8188 0.13 0.07 0.06 0.13 0.07 0.05 0.15 0.08 0.06 0.13 0.08 0.06 0.12 0.07 0.05

R73 30.2628 -87.6065 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.07 0.04 0.04 0.09 0.05 0.04

R74 30.2290 -87.8182 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.08 0.05 0.04 0.1 0.05 0.04

R75 30.2364 -87.7659 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.08 0.05 0.04 0.1 0.05 0.04

R76 30.2431 -87.7150 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.08 0.05 0.04 0.09 0.05 0.04

R77 30.3047 -89.2769 0.18 0.1 0.07 0.14 0.07 0.06 0.2 0.11 0.09 0.17 0.1 0.08 0.16 0.09 0.07

R78 30.3218 -89.2231 0.18 0.1 0.07 0.13 0.07 0.06 0.2 0.11 0.09 0.18 0.1 0.08 0.16 0.09 0.07

R8 29.0826 -89.2429 0.42 0.26 0.22 0.32 0.2 0.18 0.48 0.29 0.25 0.41 0.26 0.23 0.38 0.23 0.19

R9 29.0275 -89.2209 0.45 0.28 0.24 0.34 0.21 0.19 0.52 0.32 0.28 0.45 0.3 0.26 * 0.40 0.24 0.21

R79 29.0450 -90.8159 0.18 0.1 0.09 0.16 0.09 0.08 0.22 0.13 0.11 0.18 0.11 0.1 0.2 0.11 0.09

R80 29.0531 -90.8637 0.17 0.1 0.09 0.15 0.09 0.08 0.21 0.12 0.11 0.18 0.11 0.1 0.2 0.11 0.09

R81 29.0481 -90.9178 0.16 0.1 0.08 0.15 0.09 0.07 0.21 0.12 0.1 0.17 0.11 0.09 0.19 0.11 0.09

R82 29.0660 -90.9576 0.16 0.09 0.08 0.15 0.08 0.07 0.2 0.12 0.1 0.17 0.1 0.09 0.19 0.11 0.09

R83 29.1742 -91.0085 0.16 0.09 0.08 0.14 0.08 0.07 0.2 0.11 0.09 0.16 0.1 0.09 0.18 0.1 0.08

R84 29.1836 -91.0620 0.15 0.09 0.07 0.14 0.08 0.07 0.19 0.11 0.09 0.16 0.09 0.08 0.18 0.1 0.08

R85 29.2040 -91.1063 0.15 0.08 0.07 0.13 0.08 0.06 0.18 0.11 0.09 0.16 0.09 0.08 0.17 0.09 0.08

R86 29.2220 -91.1515 0.14 0.08 0.07 0.13 0.07 0.06 0.18 0.1 0.09 0.15 0.09 0.08 0.17 0.09 0.07

R87 29.2246 -91.2011 0.14 0.08 0.07 0.13 0.07 0.06 0.18 0.1 0.08 0.15 0.09 0.07 0.16 0.09 0.07

R88 29.2391 -91.2479 0.14 0.08 0.07 0.12 0.07 0.06 0.17 0.1 0.08 0.14 0.08 0.07 0.16 0.09 0.07

R89 29.2589 -91.2920 0.13 0.07 0.06 0.12 0.07 0.06 0.17 0.09 0.08 0.14 0.08 0.07 0.16 0.09 0.07

R90 29.2916 -91.3251 0.13 0.07 0.06 0.12 0.07 0.05 0.16 0.09 0.08 0.14 0.08 0.07 0.15 0.08 0.07

R91 28.8860 -89.4362 * 0.48 * 0.32 * 0.29 * 0.43 * 0.29 * 0.26 0.48 0.32 0.29 0.42 0.3 0.28 0.39 * 0.27 * 0.24

R92 30.2733 -87.5576 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.07 0.04 0.03 0.08 0.04 0.03

R93 30.2812 -87.5080 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.07 0.04 0.03 0.08 0.04 0.03

R94 30.2915 -87.4594 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.07 0.04 0.03 0.08 0.04 0.03

R95 30.2991 -87.4104 0.1 0.05 0.04 0.09 0.05 0.04 0.07 0.04 0.03 0.07 0.04 0.03 0.08 0.04 0.03

R96 30.3101 -87.3627 0.09 0.05 0.04 0.09 0.05 0.03 0.07 0.03 0.03 0.06 0.04 0.03 0.08 0.04 0.03

R97 30.3208 -87.3140 0.09 0.05 0.04 0.09 0.04 0.03 0.07 0.03 0.03 0.06 0.04 0.03 0.08 0.04 0.03

R98 30.3171 -87.2631 0.09 0.05 0.04 0.08 0.04 0.03 0.06 0.03 0.02 0.06 0.04 0.03 0.08 0.04 0.03

R99 30.3216 -87.2131 0.09 0.05 0.04 0.08 0.04 0.03 0.06 0.03 0.02 0.06 0.04 0.03 0.09 0.04 0.03

R100 30.3276 -87.1632 0.09 0.05 0.04 0.07 0.04 0.03 0.06 0.03 0.02 0.07 0.04 0.03 0.09 0.05 0.03

+ Represents Class I Area receptor.

* Represents maximum annual average concentration corresponding to the meteorological year and mixing height represented for each column.

Receptor Lat, dd Lon, dd

2000

OCD5 Predicted Exploration Plan Annual Average NO2 Concentrations - μg/m3

2000, 2001, 2002, 2003 and 2004 Meteorology - 300m, 600m, 900m Mixing Heights

2001 2002 2003 2004

Shell Offshore, Inc.- OCD Modeling

Annual Model summary_v2.0 - Mars B Batch Annual OCD results 1 of 1

Trinity Consultants

June 2011
Table C-2. Shell Offshore, Inc. - OCD Modeling Results

Mars B Batch Exploration Plan - Mississippi Canyon

300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 900 m

B1+ 29.4851 -89.1701 38.78 38.78 38.78 20.43 20.43 20.43 38.77 38.77 38.77 38.77 38.77 38.77 38.77 38.77 38.77

B2+ 29.4623 -89.2030 39.91 39.91 39.91 22.4 22.4 22.4 39.9 39.9 39.9 39.9 39.9 39.9 39.9 39.9 39.9

C1+ 29.9088 -88.8219 13.57 13.54 13.54 21.96 21.96 21.96 26.82 26.82 26.82 25.46 25.46 25.46 18.69 18.69 18.69

C2+ 29.9524 -88.8261 15.52 15.52 15.52 20.28 20.28 20.28 27.04 27.04 27.04 24.64 24.64 24.64 17.59 17.59 17.59

C3+ 29.8669 -88.8371 14.75 14.75 14.75 22.11 22.11 22.11 27.83 27.83 27.83 26.05 26.05 26.05 19.02 19.02 19.02

C4+ 29.8345 -88.8373 14.13 13.65 13.65 23.14 23.14 23.14 27.81 27.81 27.81 26.59 26.59 26.59 19.55 19.55 19.55

C5+ 29.7925 -88.8604 16.44 16.44 16.44 22.62 22.62 22.62 29.47 29.47 29.47 27.14 27.14 27.14 19.6 19.6 19.6

R1 29.0003 -89.3673 52.81 52.81 52.81 34.39 34.39 34.39 31.82 31.82 31.82 41.45 41.45 41.45 28.95 28.89 28.89

R10 29.0048 -89.1778 61.55 61.55 61.55 27.32 20.65 20.65 56.89 56.89 56.89 56.88 56.88 56.88 56.89 56.89 56.89

R11 28.9900 -89.1422 56.62 56.62 56.62 29.04 16.47 16.46 45.23 45.23 45.23 56.73 56.73 56.73 42.83 42.83 42.83

R12 29.0749 -89.1185 47.22 47.22 47.22 26.72 14.2 14.18 44.76 44.76 44.76 52.63 52.63 52.63 33.47 33.47 33.47

R13 29.0528 -89.1568 57.28 57.28 57.28 25.24 15.56 15.55 48.4 48.4 48.4 48.71 48.71 48.71 48.4 48.4 48.4

R14 29.0887 -89.0727 36.78 36.78 36.78 26.18 20.37 20.37 54.51 54.51 54.51 45.4 45.4 45.4 34.62 34.62 34.62

R15 29.1338 -89.0453 38.14 38.14 38.14 27.05 27.05 27.05 52.72 52.72 52.72 39.74 39.74 39.74 35.92 35.92 35.92

R16 29.1791 -89.0052 26.88 26.88 26.88 36.13 36.13 36.13 47.32 47.32 47.32 43.44 43.44 43.44 31.53 31.53 31.53

R17 29.2150 -89.0270 35.03 35.03 35.03 25.58 25.58 25.58 48.63 48.63 48.63 37.13 37.13 37.13 32.99 32.99 32.99

R18 29.2967 -89.1575 45.75 45.75 45.75 20.38 15.77 15.77 42.52 42.52 42.52 42.51 42.51 42.51 42.52 42.52 42.52

R19 29.3382 -89.1836 43.95 43.95 43.95 24.28 24.28 24.28 43.94 43.94 43.94 43.93 43.93 43.93 43.94 43.94 43.94

R2 28.9636 -89.4025 * 63.84 * 63.84 * 63.84 29.54 17.98 17.97 40.87 40.87 40.87 43.72 43.72 43.72 35.45 35.45 35.45

R20 29.3495 -89.2666 35.81 35.81 35.81 20.7 10.92 10.88 35.8 35.8 35.8 36.59 36.59 36.59 35.8 35.8 35.8

R21 29.3881 -89.3120 25.16 25.16 25.16 20.01 12.07 12.07 31.54 31.54 31.54 36.07 36.07 36.07 28.27 28.27 28.27

R22 29.2529 -89.1174 44.17 44.17 44.17 21.82 10.94 10.9 34.27 34.27 34.27 42.37 42.37 42.37 34.27 34.27 34.27

R23 29.7637 -89.2865 25.33 25.33 25.33 15.33 7.66 6.94 25.33 25.33 25.33 27.79 27.79 27.79 25.33 25.33 25.33

R24 29.0430 -89.3525 42.4 42.4 42.4 38.64 38.64 38.64 36.85 36.85 36.85 37.97 37.97 37.97 33.94 33.94 33.94

R25 30.3367 -89.1708 23.94 23.94 23.94 13.53 13.52 13.52 23.94 23.94 23.94 23.94 23.94 23.94 23.94 23.94 23.94

R26 29.0826 -89.3137 28.14 28.13 28.13 26.27 25.63 25.63 40.48 40.48 40.48 42.64 42.64 42.64 39.92 39.92 39.92

R27 29.1272 -89.3603 37.67 37.67 37.67 35.37 35.37 35.37 33.75 33.75 33.75 35.04 35.04 35.04 31.84 31.84 31.84

R28 29.1564 -89.3973 46.04 46.04 46.04 26.7 26.7 26.7 27.25 27.25 27.25 35.4 35.4 35.4 26.51 26.51 26.51

R29 29.1875 -89.4501 23.34 23.34 23.34 12.82 12.82 12.82 30.73 30.73 30.73 34.63 34.63 34.63 28.85 28.85 28.85

R3 28.9287 -89.4210 62.79 62.79 62.79 31.19 28.71 28.71 43.15 43.15 43.15 57.8 57.8 57.8 47.63 47.63 47.63

R30 30.3560 -89.1167 23.28 23.28 23.28 11.78 11.78 11.78 23.28 23.28 23.28 23.27 23.27 23.27 23.28 23.28 23.28

R31 29.2342 -89.4950 12.95 12.95 12.95 21.11 21.11 21.11 24.23 24.23 24.23 31.34 31.34 31.34 36.3 36.3 36.3

R32 29.2424 -89.5571 30.85 30.85 30.85 31.13 31.13 31.13 32.85 32.85 32.85 46.59 46.59 46.59 30.17 30.17 30.17

R33 29.2544 -89.6062 31.64 31.64 31.64 29.62 29.62 29.62 29.7 29.7 29.7 40.92 40.92 40.92 30.01 30.01 30.01

R34 29.2838 -89.6352 29.41 29.41 29.41 29.43 29.43 29.43 28.29 28.29 28.29 36.19 36.19 36.19 30.03 30.03 30.03

R35 29.2950 -89.6813 21.77 21.77 21.77 27.26 27.26 27.26 24.56 24.56 24.56 27.7 27.7 27.7 28.18 28.18 28.18

R36 29.3057 -89.7325 20 11.92 11.92 29.06 29.06 29.06 24.47 24.47 24.47 32.53 32.53 32.53 36.73 36.73 36.73

R37 29.3129 -89.7805 19.26 9.63 8.04 25.54 25.54 25.54 23.53 23.53 23.53 35.78 35.78 35.78 41.14 41.14 41.14

R38 29.3192 -89.8416 19.29 9.65 8.27 27.63 27.63 27.63 24.55 24.55 24.55 28.21 28.21 28.21 39.43 39.43 39.43

R39 29.3063 -89.8803 19.27 9.64 8.33 34.9 34.9 34.9 32.68 32.68 32.68 27.27 27.27 27.27 33.66 33.66 33.66

R4 28.9530 -89.3799 62.33 62.33 62.33 29.64 24.11 24.11 39.95 39.94 39.94 43.49 43.49 43.49 39.03 39.03 39.03

R40 29.2830 -89.9251 19.31 9.66 7.82 39.13 39.13 39.13 39.86 39.86 39.86 27.87 27.87 27.87 23.45 23.45 23.45

R41 30.2407 -88.7347 11.34 10.68 10.68 18.71 18.71 18.71 22.26 22.26 22.26 21.39 21.39 21.39 15.68 15.68 15.68

R42 30.2334 -88.6836 11.07 5.53 5.22 19.59 19.59 19.59 19.17 19.17 19.17 20 20 20 12.11 12.1 12.1

R43 30.2264 -88.6337 11.47 5.74 4.61 17.51 17.51 17.51 16.63 16.63 16.63 18.15 18.15 18.15 16.57 16.57 16.57

R44 30.2123 -88.5057 13.99 13.99 13.99 11.41 7.11 7.11 11.41 7.13 7.13 21.96 21.96 21.96 16.01 16.01 16.01

R45 30.1981 -88.4514 16.37 16.37 16.37 11.42 5.71 3.94 11.33 5.67 4.99 20.13 20.13 20.13 14.76 14.76 14.76

R46 30.2287 -88.3314 16.25 16.25 16.25 10.9 5.45 3.63 10.9 9.42 9.42 16.97 16.97 16.97 19.81 19.81 19.81

R47 30.2334 -88.2799 15.27 15.27 15.27 11 5.5 3.67 11.63 11.63 11.63 19.28 19.28 19.28 17.36 17.36 17.36

R48 30.2426 -88.2289 13.11 13.11 13.11 10.88 5.44 3.63 13.03 13.03 13.03 19.91 19.91 19.91 12.44 12.44 12.44

R49 30.2490 -88.1776 10.59 10.3 10.3 10.59 5.3 3.53 14.04 14.04 14.04 18.94 18.94 18.94 10.76 7.46 7.46

R5 28.9880 -89.3502 47.4 47.4 47.4 40.49 40.49 40.49 38.5 38.5 38.5 39.7 39.7 39.7 34.23 34.23 34.23

R50 30.2429 -88.1249 10.7 7.08 7.08 10.52 5.26 3.51 14.43 14.43 14.43 16.25 16.25 16.25 10.52 5.26 3.92

R51 30.2179 -88.0981 10.62 5.31 5.12 10.75 5.37 3.58 14.22 14.22 14.22 15.96 15.96 15.96 10.75 7.14 7.14

R52 30.2254 -88.0262 9.94 6.91 6.91 10.45 5.22 3.48 12.52 12.52 12.52 17.41 17.41 17.41 12.98 12.98 12.98

R53 30.2295 -87.9749 10.31 10.13 10.13 10.48 5.24 3.5 10.79 10.79 10.79 18.59 18.59 18.59 14.5 14.5 14.5

R54 30.2312 -87.9224 12.93 12.93 12.93 10.38 5.19 3.52 10.38 8.81 8.81 16.67 16.67 16.67 15.35 15.35 15.35

R55 30.2293 -87.8697 14.06 14.06 14.06 10.11 5.06 3.43 10.28 6.81 6.81 15.05 15.05 15.05 17.24 17.24 17.24

R56 30.3789 -89.0398 23.25 23.25 23.25 9.97 4.99 4.56 20.02 20.02 20.02 20.02 20.02 20.02 20.02 20.02 20.02

R57 30.3905 -88.9739 21.12 21.12 21.12 10.8 5.4 3.78 16.8 16.8 16.8 21.12 21.12 21.12 15.97 15.97 15.97

R58 30.0506 -89.1956 27.32 27.32 27.32 14.65 14.65 14.65 27.32 27.32 27.32 27.31 27.31 27.31 27.32 27.32 27.32

R59 30.2497 -87.6604 13.03 13.03 13.03 9.8 4.9 4.28 9.73 5.39 5.39 16.1 16.1 16.1 15.3 15.3 15.3

R6 29.0187 -89.3147 32.91 32.91 32.91 30.92 30.92 30.92 41.8 41.8 41.8 43.14 43.14 43.14 42.81 42.81 42.81

R60 29.0452 -90.7606 14.37 7.19 5.95 23.28 23.28 23.28 31.06 31.06 31.06 30.22 30.22 30.22 16.6 16.6 16.6

R61 29.0549 -90.7036 15.52 7.76 5.38 27.98 27.98 27.98 30.52 30.52 30.52 31.72 31.72 31.72 15.66 9.36 9.36

R62 29.0891 -90.5456 16.6 15.41 15.41 33.4 33.4 33.4 19.42 19.42 19.42 23.87 23.87 23.87 16.6 8.3 5.75

R63 29.0584 -90.4559 21.73 21.73 21.73 35.51 35.51 35.51 17.55 15.32 15.32 26.37 26.37 26.37 17.55 8.77 7.04

R64 29.0659 -90.3210 21.77 21.77 21.77 25.64 25.64 25.64 18.72 9.36 8.09 25.64 25.64 25.64 18.72 10.13 10.13

R65 29.0860 -90.2228 19.24 9.62 7.92 26.8 26.8 26.8 19.38 17.97 17.97 37.75 37.75 37.75 26.18 26.18 26.18

R66 29.1089 -90.1794 19.52 10.39 10.31 27.93 27.93 27.93 24.91 24.91 24.91 36.85 36.85 36.85 35.43 35.43 35.43

R67 29.1330 -90.1383 19.61 10.08 10 25.85 25.85 25.85 27.35 27.35 27.35 28.97 28.97 28.97 38.65 38.65 38.65

R68 29.1598 -90.0977 19.62 9.81 7.97 19.66 19.66 19.66 29.96 29.96 29.96 30.2 30.2 30.2 33.54 33.54 33.54

R69 29.1867 -90.0546 18.98 9.49 6.83 27.21 27.21 27.21 22.91 22.91 22.91 39.19 39.19 39.19 22.89 22.89 22.89

R7 29.0549 -89.2832 38.33 38.33 38.33 27.23 14.66 14.65 42.3 42.3 42.3 50.63 50.63 50.63 38.33 38.33 38.33

R70 29.2253 -90.0056 19.53 9.76 7.69 28.45 28.45 28.45 33.56 33.56 33.56 40.43 40.43 40.43 19.53 10.75 10.75

R71 29.2511 -89.9598 19.26 9.63 6.42 36.27 36.27 36.27 40.66 40.66 40.66 32.85 32.85 32.85 19.5 14.45 14.45

R72 30.3605 -88.8188 16.37 16.37 16.37 11 9.98 9.98 23.29 23.29 23.29 18.1 18.1 18.1 15.41 15.41 15.41

R73 30.2628 -87.6065 14.24 14.24 14.24 9.67 6.25 6.25 9.67 7.31 7.31 16.7 16.7 16.7 15.69 15.69 15.69

R74 30.2290 -87.8182 13.9 13.9 13.9 10.19 5.09 3.4 10.19 5.09 5.09 17.14 17.14 17.14 15.49 15.49 15.49

R75 30.2364 -87.7659 14.66 14.66 14.66 9.97 4.99 3.32 10.05 5.02 4.41 18.01 18.01 18.01 11.83 11.83 11.83

R76 30.2431 -87.7150 14.36 14.36 14.36 9.89 4.95 3.3 9.9 4.95 4.31 17.65 17.65 17.65 13.32 13.32 13.32

R77 30.3047 -89.2769 20.54 20.54 20.54 11.46 5.73 4.51 20.53 20.53 20.53 20.53 20.53 20.53 20.53 20.53 20.53

R78 30.3218 -89.2231 22.98 22.98 22.98 10.95 9.75 9.75 22.98 22.98 22.98 22.97 22.97 22.97 22.98 22.98 22.98

R8 29.0826 -89.2429 51.53 51.53 51.53 26.22 17.28 17.28 51.52 51.52 51.52 51.51 51.51 51.51 51.52 51.52 51.52

R9 29.0275 -89.2209 59.36 59.36 59.36 31.95 31.95 31.95 * 59.35 * 59.35 * 59.35 59.34 59.34 59.34 * 59.35 * 59.35 * 59.35

R79 29.0450 -90.8159 14.65 7.33 6.1 20.46 20.46 20.46 29.58 29.58 29.58 27.47 27.47 27.47 18.52 18.52 18.52

R80 29.0531 -90.8637 14.52 7.26 5.79 18.59 18.59 18.59 27.95 27.95 27.95 25.29 25.29 25.29 17.46 17.46 17.46

R81 29.0481 -90.9178 14.21 7.11 4.95 14.72 14.72 14.72 24.83 24.83 24.83 21.43 21.43 21.43 14.21 13.01 13.01

R82 29.0660 -90.9576 13.89 6.95 4.72 14.09 14.09 14.09 24.05 24.05 24.05 20.67 20.67 20.67 13.88 12.3 12.3

R83 29.1742 -91.0085 12.6 6.3 4.96 18.95 18.95 18.95 26.76 26.76 26.76 25.62 25.62 25.62 15.43 15.43 15.43

R84 29.1836 -91.0620 12.64 6.32 4.91 17.84 17.84 17.84 25.7 25.7 25.7 23.97 23.97 23.97 15.97 15.97 15.97

R85 29.2040 -91.1063 12.4 6.2 4.76 17.26 17.26 17.26 25.01 25.01 25.01 23.21 23.21 23.21 15.64 15.64 15.64

R86 29.2220 -91.1515 12.2 6.1 4.6 16.56 16.56 16.56 24.26 24.26 24.26 22.32 22.32 22.32 15.25 15.25 15.25

R87 29.2246 -91.2011 12.12 6.06 4.32 14.8 14.8 14.8 22.81 22.81 22.81 20.39 20.39 20.39 13.9 13.9 13.9

R88 29.2391 -91.2479 11.88 5.94 4.08 13.79 13.79 13.79 21.84 21.84 21.84 19.29 19.29 19.29 12.82 12.82 12.82

R89 29.2589 -91.2920 11.64 5.82 3.92 13.28 13.28 13.28 21.23 21.23 21.23 18.68 18.68 18.68 12.27 12.27 12.27

R90 29.2916 -91.3251 11.4 5.7 3.96 14.01 14.01 14.01 21.52 21.52 21.52 19.27 19.27 19.27 13.15 13.15 13.15

R91 28.8860 -89.4362 54.97 54.97 54.97 * 45.12 * 45.12 * 45.12 48.1 48.1 48.1 * 68.84 * 68.84 * 68.84 46.17 46.17 46.17

R92 30.2733 -87.5576 15.65 15.65 15.65 9.47 8.24 8.24 9.53 9.12 9.12 17.83 17.83 17.83 14.92 14.92 14.92

R93 30.2812 -87.5080 16.96 16.96 16.96 10.25 10.25 10.25 10.86 10.86 10.86 18.75 18.75 18.75 13.17 13.17 13.17

R94 30.2915 -87.4594 17.9 17.9 17.9 11.68 11.68 11.68 12.03 12.03 12.03 19.24 19.24 19.24 11.04 11.04 11.04

R95 30.2991 -87.4104 18.61 18.61 18.61 12.53 12.53 12.53 12.7 12.7 12.7 19.43 19.43 19.43 8.88 8.66 8.66

R96 30.3101 -87.3627 18.93 18.93 18.93 12.55 12.55 12.55 12.68 12.68 12.68 19.26 19.26 19.26 8.96 6.66 6.66

R97 30.3208 -87.3140 18.98 18.98 18.98 11.9 11.9 11.9 12.12 12.12 12.12 18.81 18.81 18.81 8.96 4.93 4.93

R98 30.3171 -87.2631 18.76 18.76 18.76 10.23 10.23 10.23 10.71 10.71 10.71 17.95 17.95 17.95 8.86 4.43 3.12

R99 30.3216 -87.2131 18.14 18.14 18.14 8.34 8.34 8.34 9.07 9.07 9.07 16.85 16.85 16.85 8.79 4.4 3.33

R100 30.3276 -87.1632 17.26 17.26 17.26 8.42 6.48 6.48 8.67 7.38 7.38 15.76 15.76 15.76 8.67 4.84 4.84

+ Represents Class I Area receptor.

2001 2002 2003

OCD5 Predicted Exploration Plan 1-hr Average NO2 Concentrations - μg/m3

2000, 2001, 2002, 2003 and 2004 Meteorology - 300m, 600m, 900m Mixing Heights

* Represents maximum 1-hr average concentration corresponding to the meteorological year and mixing height represented for each column.

Receptor Lat, dd Lon, dd

2000 2004

Shell Offshore, Inc.- OCD Modeling

1-hr Model summary_v1.1 - Mars B Batch-1-hr OCD results 1 of 1

Trinity Consultants 

June 2011
ATTACHMENT D: MODELING RESULTS FOR BRETON
Table D-1. OCD Modeled Concentrations for Breton Receptors - 1-Hour NO2 Standard

Mars B Well Batch Set Operations

Receptor Lat, dd Lon, dd 300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 90

B1 29.4851 -89.1701 38.78 38.78 38.78 20.43 20.43 20.43 38.77 38.77 38.77 38.77 38.77 3B2 29.4623 -89.2030 *39.91 *39.91 *39.91 *22.4 *22.4 *22.4 *39.9 *39.9 *39.9 *39.9 *39.9 *3

C1 29.9088 -88.8219 13.57 13.54 13.54 21.96 21.96 21.96 26.82 26.82 26.82 25.46 25.46 2C2 29.9524 -88.8261 15.52 15.52 15.52 20.28 20.28 20.28 27.04 27.04 27.04 24.64 24.64 2C3 29.8669 -88.8371 14.75 14.75 14.75 22.11 22.11 22.11 27.83 27.83 27.83 26.05 26.05 2C4 29.8345 -88.8373 14.13 13.65 13.65 23.14 23.14 23.14 27.81 27.81 27.81 26.59 26.59 2C5 29.7925 -88.8604 16.44 16.44 16.44 22.62 22.62 22.62 29.47 29.47 29.47 27.14 27.14 2

OCD5 Predicted Exploration Plan 1-hr Average NO2 Concentrations 

2000, 2001, 2002, 2003 and 2004 Meteorology - 300m, 600m, 900m Mixing Heights

* Represents maximum 1-hr average concentration corresponding to the meteorological year and mixing height represented for each column.

2000 2001 

NO2 CONCENTRATION (μg/m3)

Year 2002 2003
Table D-2. OCD Modeled Concentrations for Breton Receptors - Annual NO2 Standard

Mars B Well Batch Set Operations

Receptor Lat, dd Lon, dd 300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 900 m 300 m 600 m 90

B1 29.4851 -89.1701 0.29 0.17 0.14 0.22 0.13 0.11 0.35 0.2 0.16 0.3 0.19 0B2 29.4623 -89.2030 *0.3 *0.17 *0.14 *0.22 *0.13 *0.11 *0.35 *0.2 *0.17 *0.3 *0.19 *0

C1 29.9088 -88.8219 0.16 0.09 0.07 0.14 0.08 0.07 0.17 0.1 0.08 0.13 0.08 0C2 29.9524 -88.8261 0.16 0.08 0.07 0.14 0.08 0.06 0.17 0.1 0.08 0.13 0.08 0C3 29.8669 -88.8371 0.16 0.09 0.07 0.15 0.08 0.07 0.18 0.1 0.08 0.13 0.08 0C4 29.8345 -88.8373 0.16 0.09 0.07 0.15 0.08 0.07 0.18 0.1 0.08 0.14 0.08 0C5 29.7925 -88.8604 0.17 0.09 0.08 0.16 0.09 0.07 0.19 0.11 0.09 0.14 0.09 0

OCD5 Predicted Exploration Plan Annual Average NO2 Concentrations 

2000, 2001, 2002, 2003 and 2004 Meteorology - 300m, 600m, 900m Mixing Heights

2001 2002 2003 

* Represents maximum annual average concentration corresponding to the meteorological year and mixing height represented for each column.

Year 2000

NO2 CONCENTRATION (μg/m3)
Section 9: OIL SPILL INFORMATION

A. Oil Spill Response Planning

All the proposed activities and facilities in this SEP are covered by the Regional OSRP filed by Shell Offshore Inc 

(0689) in accordance with 30 CFR 250. An update to the Regional OSRP was filed with the BOEMRE October 26, 

2010, March 15, 2011, May 31, 2011, July 6, 2011 and August 1, 2011 and is pending approval. An update to the 

OSRP Certification in accordance with 30 CFR 254.2 was submitted to the BOEMRE August 1, 2011 and accepted on 

August 4, 2010. 

 Spill Response Sites: 

Primary Response Equipment Locations Preplanned Staging Location(s) 

Fourchon, LA; Cameron, LA; Houma, LA; Lake 

Charles, LA 

Lake Charles, LA ; Cameron, LA ; Fourchon ; LA

The names of the oil spill removal organizations (OSRO’s) under contract include Clean Gulf Associates (CGA), 

Marine Spill Response Company (MSRC), Clean Caribbean America (CCA), and OSRL/EARL. 

Worst Case Scenario Determination: 

Category Regional OSRP EP 

Type of Activity1 Drilling Rig Drilling Rig 

Facility Location (area/block) MC 807 MC 807 

Facility Designation2 Subsea well “A” Subsea well “A” 

Distance to Nearest Shoreline (miles) 53 53 

Volume3

Storage tanks (total) 

Flowlines (on facility) 

Pipelines 

Uncontrolled blowout (volume per day) 

Total Volume 

N/A 

N/A 

N/A 

465,000** BOPD 

465,000 Bbls 

N/A 

N/A 

N/A 

465,000** BOPD 

465,000 Bbls 

Type of Oil(s) - (crude oil, condensate, 

diesel) 

Crude oil Crude oil 

API Gravity(s)4 26o 26o 

 *24 hour rate (365,000 BOPD 30 day average) 

**24 hour rate (365,000 BOPD 30 day average) 

Footnotes: 

1. Types of activities include pipeline, platform, caisson, subsea completion or manifold, and mobile drilling rig. 

2. E.g., Well No. 2, Platform JA, Pipeline Segment No. 6373. 

3. Your regional OSRP worst-case scenario volume must be taken from the appropriate section of your regional OSRP. For EP’s, the worst-case 

scenario volume must be determined by using the daily worst-case discharge volume determined using the guidance at 30 CFR 254.47(b). For 

DOCD’s, the daily worst-case discharge volume must be determined by using the guidance at 30 CFR 254.47 (a) and/or (b), as appropriate. 

4. Provide API gravity of all oils given under “Type of Oil(s)” above. Estimate for EP’s. 

Shell Offshore, Inc submitted the new worst-case scenario to the BOEMRE GOMR on August 1, 2011 for inclusion in our 

regional OSRP. This plan contains the update for NTL 2010 06 review. 

Since Shell Offshore Inc has the capability to respond to the appropriate worst-case spill scenario included in its regional 

OSRP submitted October 26, 2010, March 15, 2011, May 31, 2011, July 6, 2011 and August 1, 2011, and since the 

worst-case scenario determined for our EP does not replace the appropriate worst-case scenario in our regional or subregional OSRP, I hereby certify that Shell Offshore Inc has the capability to respond, to the maximum extent practicable, 

to a worst-case discharge, or a substantial threat of such a discharge, resulting from the activities proposed in our EP. 
B Oil Spill Response Discussion

1. Volume of the Worst Case Discharge 

Please refer to Section 2j and 9(iv) of this EP. 

2. Trajectory Analysis 

Trajectories of a spill and the probability of it impacting a land segment have been projected 

utilizing information in the BOEMRE Oil Spill Risk Analysis Model (OSRAM) for the Central and 

Western Gulf of Mexico available on the BOEMRE website using 30 day impact. Offshore areas along 

the trajectory between the source and land segment contact could be impacted. The land segment 

contact probabilities are shown in Table 9.C.1. 

Area/Block OCS-G Launch 

Area Land Segment Contact % 

Exploratory 

MC807 58 

Galveston, TX 1 

Jefferson, TX 1 

Cameron, LA 3 

Vermilion, LA 2 

Iberia, LA 1 

Terrebonne, LA 3 

Lafourche, LA 3 

Jefferson, LA 1 

Plaquemines, LA 8 

St. Bernard, LA 1 

Okaloosa, FL 1 

Table 9.C.1 Probability of Land Segment Impact 

C. Resource Identification

The locations identified in Table 9.C.1 are the highest probable land segments to be impacted using 

the BOEMRE Oil Spill Risk Analysis Model (OSRAM). The environmental sensitivities are identified 

using the appropriate National Oceanic and Atmospheric Administration (NOAA) Environmental 

Sensitivity Index (ESI) maps for the given land segment. ESI maps provide a concise summary of 

coastal resources that are at risk if an oil spill occurs nearby. Examples of at-risk resources include 

biological resources (such as birds and shellfish beds), sensitive shorelines (such as marshes and 

tidal flats), and human-use resources (such as public beaches and parks). 

In the event an oil spill occurs, ESI maps can help responders meet one of the main response 

objectives: reducing the environmental consequences of the spill and the cleanup efforts. 

Additionally, ESI maps can be used by planners to identify vulnerable locations, establish protection 

priorities, and identify cleanup strategies. 

The following is a list of resources of special economic or environmental importance that potentially 

could be impacted by the Mississippi Canyon 807 WCD scenario. 

 
Onshore/Nearshore: Plaquemines Parish has been identified as the most probable impacted 

Parish within the Gulf of Mexico for the Greater than 10 Mile Worst Case Discharge and the 

Exploratory Worst Case Discharge. Plaquemines Parish has a total area of 2,429 square miles of 

which, 845 square miles of it is land and 1,584 square miles is water. Plaquemines Parish includes 

two National Wildlife Refuges: Breton National Wildlife Refuge and Delta National Wildlife Refuge. 

This area is also a nesting ground for the brown pelican, an endangered species. Examples of 

Environmental Sensitivity maps for Plaquemines Parish are detailed in the following pages. Key ESI 

maps for Plaquemines Parish and the legend are shown in Figures 9.C.1through 9.C.5. 

Offshore: An offshore spill may require an Essential Fishing Habitat (EFH) Assessment. This 

assessment would include a description of the spill, analysis of the potential adverse effects on EFH and 

the managed species; conclusions regarding the effects on the EFH; and proposed mitigation, if 

applicable. 

Significant pre-planning of joint response efforts was undertaken in response to provisions of the 

National Contingency Plan (NCP). Area Contingency Plans (ACPs) were developed to provide a well 

coordinated response to oil discharges and other hazardous releases. The One Gulf Plan is specific to the 

Gulf of Mexico to advance the unity of policy and effort in each of the Gulf Coast ACPs. Strategies used 

for the response to an oil spill regarding protection of identified resources are detailed in the One Gulf 

Plan and relevant Gulf Coast ACP. 

 D. Worst Case Discharge Response 

Shell will make every effort to respond to the MC 807 Worst Case Discharge as effectively as 

possible. Applied Science Associates (ASA) conducted a deepwater blowout simulation for The 

Response Group to better determine subsurface and surface evaporation and dispersion rates. 

Below is a table outlining the applicable evaporation and dispersion quantities: 

Mississippi Canyon 807 

Calculations 

(BBLS) 

i. 30 Day Average WCD = 365,.000 bbls 

ii. Subsurface dispersion – 25% (Water Depth = ~3,000 ft) -91,000 bbls 

iii. REMAINING WCD AFTER SUBSURFACE DISPERSION 274,000 bbls 

iv. Surface dispersion and evaporation – 25% -68,000 bbls 

TOTAL REMAINING ~206,000 bbls 

Table 9.D.1 Oil Remaining After Subsurface and Surface Dispersion 

Shell has contracted OSROs to provide equipment, personnel, materials and support vessels as well 

as temporary storage equipment to be considered in order to cope with a WCD spill. Under adverse 

weather conditions, major response vessels and Transrec skimmers are still effective and safe in sea 

states of 6-8 ft. If sea conditions prohibit safe mechanical recovery efforts, then natural dispersion 

and airborne chemical dispersant application (visibility & wind conditions permitting) may be the 

only safe and viable recovery option. 

MSRC OSRV 8 foot seas 

VOSS System 4 foot seas 

Expandi Boom 6 foot seas, 20 knot winds 

Dispersants Winds more than 25 knots, 

Visibility less than 3 nautical miles, or 

Ceiling less than 1,000 feet. 

Table 9.D.2 Operational Limitations of Response Equipment 

Upon notification of the spill, Shell would request a partial or full mobilization of contracted 

resources, including, but not limited to, skimming vessels, oil storage vessels, dispersant aircraft, 

subsea dispersant, shoreline protection, wildlife protection, and containment equipment. Following 

is a list of the contracted resources including de-rated recovery capacity, personnel, and estimated 

response times (procurement, load out, travel time to the site, and deployment). The Incident 
Commander or designee may contact other service companies if the Unified Command deems such 

services necessary to the response efforts. 

Based on the anticipated worst case discharge scenario, Shell can be onsite with dedicated, contracted on water 

oil spill recovery equipment with adequate response capacity to contain and recover surface oil, and prevent 

land impact, within 46 hours (based on the equipment’s Estimated Daily Response Capacity (EDRC)). Shell 

will continue to ramp up additional on-water mechanical recovery resources as well as apply dispersants and 

in-situ burning as needed and as approved under the supervision of the USCG Captain of the Port (COTP) and 

the Regional Response Team (RRT). 

Subsea Control and Containment: Shell, as a founding member of the MWCC, will have access 

to the IRCS that can be rapidly deployed through the MWCC. The IRCS is designed to contain oil 

flow in the unlikely event of an underwater well blowout, and is designed, constructed, tested, and 

available for rapid response. Shell’s specific containment response for MC 807 will be addressed in 

Shell’s NTL10 submission at the time the APD is submitted. 

 Table 9.D.9 Control, Containment, and Subsea Dispersant Package Activation List 

Mechanical Recovery (skimming): Response strategies include skimming utilizing available 

OSROs Oil Spill Response Vessels (OSRVs), Oil Spill Response Barges (OSRBs), ID Boats, and Quick 

Strike OSRVs. There is a combined de-rated recovery rate capability of approximately 585,900 

barrels/day. Temporary storage associated with the identified skimming and temporary storage 

equipment equals approximately 297,900 barrels. 

 

De-rated Recovery Rate

(bopd) 

Storage 

(bbls) 

Offshore Recovery and 

Storage 478,907 480,900 

Nearshore Recovery and 

Storage 106,993 17,224 

Total 585,900 297,924 

Table 9.D.3 Mechanical Recovery Combined De-Rated Capability 

 Table 9.D.4 Offshore On-Water Recovery and Storage Activation List 

 Table 9.D.5 Nearshore On-Water Recovery and Storage 5ctivation List 

Oil Storage: The strategy for transferring, storing and disposing of oil collected in these recovery 

zones is to utilize two 150,000-160,000 ton (dead weight) tankers mobilized by Shell (or any other 

tanker immediately available). The recovered oil would be transferred to Motiva’s Norco, LA storage 

and refining facility, or would be stored at Delta Commodities, Inc. Harvey, LA facility.

Aerial Surveillance: Aircraft can be mobilized to detect, monitor, and target response to oil spills. 

Aircraft and spotters can be mobilized within hours of an event. 

 Table 9.D.6 Aerial Surveillance Activation List 

Aerial Dispersant: Depending on proximity to shore and water depth, dispersants may be a viable 

response option. If appropriate and approved, 4 to 5 sorties from three DC-3’s can be made within 

the first 12 hour operating day of the response. These aerial systems could disperse approximately 

7,704 to 9,630 barrels of oil per day. Additionally, 3 to 4 sorties from the BE90 King Air and 3 to 4 

sorties from the Hercules C-130A within the first 12 hour operating day of the response could 

disperse 4,600 to 6,100 barrels of oil per day. For continuing dispersant operations, the CCA’s Aerial 

Dispersant Delivery System (ADDS) would be mobilized. The ADDS has a dispersant spray capability 

of 5,000 gallons per sortie. 

 Table 9.D.7 Offshore Aerial Dispersant Activation List 

Vessel Dispersant: Vessel dispersant application is another available response option. If 

appropriate, vessel spray systems can be installed on offshore vessels of opportunity using inductor 

nozzles (installed on fire-water monitors), skid mounted systems, or purpose-built boom arm spray 

systems. Vessels can apply dispersant within the first 12-24 hours of the response and continually as 

directed. 
 Table 9.D.8 Offshore Boat Spray Dispersant Activation List 

Subsea Dispersant: Shell has contracted with Wild Well Control for a subsea dispersant package. 

Subsea dispersant application has been found to be highly effective at reducing the amount of oil 

reaching the surface. Additional data collection, laboratory tests and field tests will help in facilitating 

the optimal application rate and effectiveness numbers. For planning purposes, the system has the 

potential to disperse approximately 24,500 to 34,000 barrels of oil per day.

 Table 9.D.9 Control, Containment, and Subsea Dispersant Package Activation List 

In-Situ Burning: Open-water in-situ burning (ISB) also may be used as a response strategy, 

depending on the circumstances of the release. ISB services may be provided by the primary OSRO 

contractors. If appropriate conditions exist and approvals are granted, one or multiple ISB task 

forces could be deployed offshore. Task forces typically consist of two to four fire teams, each with 

two vessels capable of towing fire boom, guide boom or tow line with either a handheld or aeriallydeployed oil ignition system. At least one support/safety boat would be present during active 

burning operations to provide logistics, safety and monitoring support. Depending upon a number of 

factors, up to 4 burns per 12-hour day could be completed per ISB fire team. Most fire boom 

systems can be used for approximately 8-12 burns before being replaced. Fire intensity and weather 

will be the main determining factors for actual burns per system. Although the actual amount of oil 

that will be removed per burn is dependent on many factors, recent data suggests that a typical 

burn might eliminate approximately 750 barrels. For planning purposes and based on the above 

assumptions, a single task force of four fire teams with the appropriate weather and safety 

conditions could complete four burns per day and remove up to ~12,000 bbls/day. In-situ burning 

nearshore and along shorelines may be a possible option based on several conditions and with 

appropriate approvals, as outlined in Section 19, In-situ Burn Plan (OSRP). In-situ burning along 

certain types of shorelines may be used to minimize physical damage where access is limited or if it 

is determined that mechanical/manual removal may cause a substantial negative impact on the 

environment. All safety considerations will be evaluated. In addition, Shell will assess the situation 

and can make notification within 48 hours of the initial spill to begin ramping up fire boom 

production through contracted OSRO(s). There are potential limitations that need to be assessed 

prior to ISB operations. Some limitations include atmospheric and sea conditions; oil weathering; air 

quality impacts; safety of response workers; and risk of secondary fires. 

 Table 9.D.10 In-Situ Burn Equipment Activation List 

 Shoreline Protection: If the spill went unabated, shoreline impact in Plaquemines Parish, LA 

would depend upon existing environmental conditions. Nearshore response may include the 

deployment of shoreline boom on beach areas, or protection and sorbent boom on vegetated areas. 

Strategies would be based upon surveillance and real time trajectories provided by The Response 

Group that depict areas of potential impact given actual sea and weather conditions. Strategies from 

the New Orleans, Louisiana Area Contingency Plan, Unified Command would be consulted to ensure 

that environmental and special economic resources would be correctly identified and prioritized to 

ensure optimal protection. Shell has access to shoreline response guides that depict the protection 

response modes applicable for oil spill clean-up operations. Each response mode is schematically 

represented to show optimum deployment and operation of the equipment in areas of 

environmental concern. Supervisory personnel have the option to modify the deployment and 

operation of equipment allowing a more effective response to site-specific circumstances. 

 Table 9.D.11 Shoreline Protection and Wildlife Support List 

Wildlife Protection: If wildlife is threatened due to a spill, the contracted OSRO’s have resources 

available to Shell, which can be utilized to protect and/or rehabilitate wildlife. The resources under 

contract for the protection and rehabilitation of affected wildlife are in Table 9.D.11. 

New or unusual technology in regards to spill, prevention, control and clean-up: 

Shell will use our normal well design and construction processes with multiple barrier approach as 

well as new stipulations mandated by NTL 2008-N05. Response techniques will utilize new learnings 

from Macondo response to include in-situ burning and subsea dispersant application. Mechanical 

recovery advancements are continuing to be made to incorporate utilization of Koseq arms outfitted 

on barges, conversion of Platform Support Vessels for Oil Spill Response, and inclusion of nighttime 

spill detection radar to improve tracking capabilities (X-Band radar, Infrared sensing, etc.). In 

addition, new response technologies/techniques are continuing to be considered by Shell and the 
appropriate government organizations for incorporation into our planned response. Any additional 

response technologies/techniques presented at the time of response will be used at the discretion of 

the Unified Command and USCG. 

 

Figure 9.C.1 Environmental Sensitivity Index Map Legend 
Figure 9.C.2 South Pass ESI Map 
Figure 9.C.3 Garden Island Pass ESI Map 
. 

Figure 9.C.4 Pass a Loutre West ESI Map 
Figure 9.C.5 Main Pass ESI Map 
Table 9.D.4 Offshore On-Water Recovery and Storage Activation List 
Table 9.D.4 Offshore On-Water Recovery and Storage Activation List (continued) 
Table 9.D.4 Offshore On-Water Recovery and Storage Activation List (continued) 
Table 9.D.4 Offshore On-Water Recovery and Storage Activation List (continued) 
 Table 9.D.5 Nearshore On-Water Recovery Activation List 
Table 9.D.5 Nearshore On-Water Recovery Activation List (continued) 
Table 9.D.5 Nearshore On-Water Recovery Activation List (continued) 
Table 9.D.5 Nearshore On-Water Recovery Activation List (continued) 
Table 9.D.6 Aerial Surveillance Activation List 
Table 9.D.7 Offshore Aerial Dispersant Activation List 

Table 9.D.8 Offshore Boat Spray Dispersant Activation List 

Table 9.D.9 Control, Containment, and Subsea Dispersant Package Activation List 
Table 9.D.10 In-Situ Burn Equipment Activation List 
Table 9.D.10 In-Situ Burn Equipment Activation List (continued) 
Table 9.D.10 In-Situ Burn Equipment Activation List (continued) 
Table 9.D.10 In-Situ Burn Equipment Activation List (continued) 
Table 9.D.10 In-Situ Burn Equipment Activation List (continued) 
Table 9.D.11 Shoreline Protection and Wildlife Support List 
Section 10: Environmental Monitoring Information

A. Monitoring Systems 

A rig based Acoustic Doppler Current Profiler (ADCP) is used to continuously monitor the current beneath 

the Rig. Metocean conditions such as sea states, wind speed, ocean currents, etc. will also be continuously 

monitored 

B. Incidental Takes 

No incidental takes are anticipated. Shell implements the mitigation measures and monitors for incidental 

takes of protected species according to the following notices to lessees and operators from the Minerals 

Management Service: 

NTL 2007-G03 “Marine Trash and Debris Awareness and Elimination” 

NTL 2007-G04 “Vessel Strike Avoidance and Injured/Dead Protected Species Reporting” 

C. Flower Garden Banks National Marine Sanctuary 

The operations proposed in this EP will not be conducted within the Protective Zones of the Flower Garden 

Banks and Stetson Bank. 
Section 11: Lease Stipulations Information

Lease OCS-G 7963 was part of Lease Sale No. 98 on May 22, 1985. This lease is part of the Mississippi Canyon 

Block 807 Unit, Unit Contract No. 754393002 approved effective 8/1/92. Unit Agreement consists of Leases OCS-G 

7957 (SE1/4), 7958 (S1/2), 7962 (E1/2), 7963, 9881 (NE1/4), and 9882 (N1/2). The Unit has been held by 

production. Shell is designated operator of the Unit.

The Unit Leases are not part of a Biological Sensitive Area, known Chemosynthetic Area, or Shipping Fairway. 

Section 12: Environmental Mitigation Measure Information

A. Impacts to Marine and coastal environments 

The proposed action will implement mitigation measures required by laws and regulations, including all 

applicable Federal & State requirements concerning air emissions, discharges to water, and solid waste 

disposal, as well as any additional permit requirements and Shell policies. Project activities will be conducted in 

accordance with the Regional Oil Spill Response Plan. The EIA attached as Section 18 to this plan discusses 

impacts and mitigation measures. 

B. Incidental Takes 

We do not anticipate any incidental takes related to the proposed operations. Shell implements the mitigation 

measures and monitors for incidental takes of protected species according to the following notices to lessees 

and operators from the Minerals Management Service: 

NTL 2007-G03 “Marine Trash and Debris Awareness and Elimination” 

NTL 2007-G04 “Vessel Strike Avoidance and Injured/Dead Protected Species Reporting” 

Section 13: Related Facilities and Operations Information

Information regarding Related Facilities and Operations Information, transportation systems, & produced liquid 

hydrocarbon transportation vessels are not included in this EP as such information is only necessary in the case of 

DOCDs. 

 
Section 14: Support Vessels and Aircraft Information

A. General 

Type Maximum Fuel Tank 

Storage Capacity (Gals) 

Maximum No. In Area at 

Any Time 

Trip Frequency or 

Duration 

Crew Boats 8,000 2 Twice per week 

Offshore Support Vessels 120,000 4 Twice per week 

Tug Boats 100,000 NA NA 

Anchor Handling Vessel 250,000 NA NA 

Helicopter 764 1 Once per day 

B. Diesel Oil Supply Vessels 

Size of Fuel Supply 

Vessel 

Capacity of Fuel Supply 

Vessel 

Frequency of Fuel 

Transfers 

Route Fuel Supply Vessel Will 

Take 

280 foot length 100,000 gals. 1 week Port Fourchon to MC 807 

C. Drilling Fluids Transportation 

Type of Material Quantity Being Transported Transportation Method 

Dry Bulk (Cement, Barite, 

Gel) 

12,000 sx max combined Below deck dry bulk tanks 

onboard OSV 

Synthetic-base drilling fluids 11,000 bbls max per voyage Drums on St. Mary Mud 

Company's supply boat 

Water Based drilling fluids 12,000 bbls max per voyage Below deck liquid mud tanks 

onboard OSV 

D. Solid and Liquid Wastes Transportation 

See Table 7B. 

E. Vicinity Map 

See Attached. 

 
!

! !

!

79 Nautical / 91 Statute Water Miles

to Fourchon Terminal

46 Nautical / 53 Statute Miles

to Nearest Shoreline

72 Nautical / 82 Statute Air Miles

to Boothville Terminal

SOUTH PASS

MISSISSIPPI

CANYON

WEST DELTA

GRAND ISLE

Port

Fourchon

Boothville Buras

Venice

21 22

5 4

878 879 876 877 875 838 874 839 873 840 872 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858

835 833 834 831 832 794 829 830 795 796 828 797 798 799 800 801 802 803 804 805

785

806

308

784

807 808 809 810 811 812 813 814

791 786 789 790 787 788 750 751 752 753 754 755 756 757

286

758

288

759 760 761 762 763 764 765 766 767 768 769 770

743 744 121 745 746 705 706 707 708 709 710

284 285

711

283

712 713 714 715 716 717 718 719 720 721 722 723 724 725 726

701 118 119 120 702 661 662 663 259 258 664

260

665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682

658 116 115 114 117

256 257 617 255 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635

113

636

112

637

110 111

638

109

230 614 232 231 573

574 575 576 577 578 579 580 581 582 583 584 585 586 587 588

105

589

107 106

590

108

591 592 593 594

227 228 229 570529 530 531 532 533 534 535 536 537 538 539

103 104 102

542

101

543 544 545 546 550

208 209 210 525 526

485 486 487 488 489 490 491 492 493

98

494

100 99

495 498 499 500 501 502 503 504 505 506

185 184 183 481 482 441 442 443 444 445 446 97 447

95 96

448 449 450 454 455 456 457 458 459 460 461 462

180 181 182 179 437 438 397 398 399 92 400 94 93 401 402 403 404 405 406 410 411 412 413 414 415 416 417 418

157 156 155 158 393 394 91 353 89 90 354 355 356 357 361 362 365 366 367 368 369 370 371 372

318

373

316 317

374

152 153 154 151 350 88 347 348 349 309 310 311 312 321 324 147 325 148 326 149 327 328 329 330

267

133 132 135 134 92

87 304 305 306 265 266 86 144 145 141 142 143 280 281 282

137

283

131

284

129 130

285

128

286

90

81 80 84 83 82 85 130 129 128 132 131 133 123

236

125 124

237

126

238 239 240 241 242

87 86 85

76 77 78 74 75 125 126 127 123 124 121 122

86 87 88 85

192 193 194 195 196 197 198

79 80 81

71 70 73 72 112 111 110 114 113 117 116 115

62 61 64 63

147 148 149 150

104

151 76 152 77 153 78 154

64 65 62 63

59 60 57 58

52 51 50 58 57 56 108 109 107 107 100 101 102 103 104 105 106 108 109 110 97 98 99

61 60

45 44 43 46

63 48 49 46 47 42 64 65

55

66

53 54 50 51 52

86 85 84 41 96 95 94

41 42 39 40 20 33 73 36 35 34 40

45 44 48 47 46 49

21 22

26 25 28 27 983

83

71 81 82 72 79 80 32 78 31 76 77 30 74 75 29 72 73 28 69 70 71

42 43 40 41 38 39

984

22 21 23 24 940

61 70 18 21 20 19 24 23 25

33 32 36 35 34 37

57 56 55 54 53 60 59 58 63 62 61 66 65 64 68 67

11 15 14 68 13 17 60 67 16

52

12

31 2 30 3

28 29 26 27 51

9 48 49 50 45 46 47 42 43 44 38 39 40 41 66 65 7 6 59 8 10

22 21 20 23 1 25 24 25 78 152 5 79

14

28 27 26 31 30 29

19

33 32

18

34

17

35

16

37 36

15 3 4

77 151 76

13

2

10 9 12 11

23 24 19 20 21 22 15 16 17 18 14

5

74 148 75

1 80

4

81

5

82

7 8 6 6

4

9 8 7 13 12 11 10 71 72 73 147 69 70 68

2 3

67 83

2 3 1 1

62 61 140 64 63 65

66 84

85 60 139 58 59 57 55 56

54 53

52 41 40 39 43 42 45 44 46 47 48 49

Mississippi Canyon Block 807

OCS-G07963

Lease Vicinity and Transportation Routes 3

...\CAD_NewOrleans\Maps\Permit Plats\W Boreas-S Deimos\Mars B Lease Vicinity and Transportation Routes.mxd

NAD_1927_UTM_Zone_16N

Projection: Transverse_Mercator

False_Easting: 1640416.666667

False_Northing: 0.000000

Central_Meridian: -87.000000

Scale_Factor: 0.999600

Latitude_Of_Origin: 0.000000

Linear Unit: Foot_US

Shell Exploration and Production Co.

Air Route

Water Route

0 4 8 2 12 16 20

Nautical Miles
Section 15: Onshore Support Facilities Information

A. General 

Name Location Existing/New/Modified 

Fourchon Port Fourchon, LA Existing 

Boothville PHI Heliport Boothville, LA Existing 

The onshore support bases for water and air transportation will be the existing terminals in Amelia and Fouchon, 

Louisiana. The Fouchon boat facility is operated by SOI and is located on Bayou Lafourche, south of Leesville, LA 

approximately 3 miles from the Gulf of Mexico. The existing onshore air support base in Boothville, LA is located at 

38936 Highway 23, Boothville, LA 70041. 

B. Support Base Construction or Expansion 

This Section does not apply to this EP as Shell does not plan to construct a new onshore support base or expand 

an existing one to accommodate the activities proposed in this EP. 

C. Support Base Construction or Expansion Timetable 

This Section does not apply to this EP as Shell does not plan to construct a new onshore support base or expand 

an existing one to accommodate the activities proposed in this EP. 

D. Waste Disposal 

See Tables 7A and 7B. 
Section 16: Sulphur Operations Information

Information regarding Sulfur Operations Information is not included in this SEP as such information is only necessary 

in the case of DOCDs. 

Section 17: Coastal Zone Management Act (CZMA) Information

Louisiana Coastal Zone Consistency was granted in Plan N-2993 approved June 3, 1988 and is not required for 

Supplmental Exploration Plans. 

18. Environmental Impact Analysis (EIA)

See attached EIA for this SEP. 

 
Environmental Impact Analysis

SUPPLEMENTAL EXPLORATION PLAN

Mississippi Canyon Block 807 (OCS‐G 7963)

Offshore Louisiana

August 2011

Prepared for:

Shell Offshore Inc.

P.O. Box 61933

New Orleans, Louisiana  70161

Telephone: (504) 728‐7215

Prepared by:

CSA International, Inc.

8502 SW Kansas Avenue

Stuart, Florida  34997

Telephone: (772) 219‐3000
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page ii

Contents

Page

Introduction ................................................................................................................1

Project Summary ....................................................................................................................................1

Purpose of the EIA..................................................................................................................................1

OCS Regulatory Framework ................................................................................................................... 3

Oil Spill Prevention and Contingency Planning ...................................................................................... 5

EIA Organization.....................................................................................................................................5

A.  Impact‐Producing Factors .......................................................................................6

A.1 Drillship Presence (including noise and lights).............................................................................. 6

A.2 Physical Disturbance to the Seafloor ............................................................................................ 6

A.3 Air Pollutant Emissions.................................................................................................................. 9

A.4 Effluent Discharges........................................................................................................................ 9

A.5 Water Intake................................................................................................................................10

A.6 Onshore Waste Disposal ............................................................................................................. 10

A.7 Marine Debris.............................................................................................................................. 10

A.8 Support Vessel and Helicopter Traffic......................................................................................... 11

A.9 Accidents.....................................................................................................................................11

A.9.1 Types of Accidents Evaluated.......................................................................................... 11

A.9.2 Small Fuel Spill................................................................................................................. 11

A.9.3 Large Oil Spill ................................................................................................................... 12

A.9.4 Other Accidents Not Analyzed in Detail .......................................................................... 15

B.  Affected Environment...........................................................................................16

C.  Impact Analysis.....................................................................................................18

C.1 Physical/Chemical Environment.................................................................................................. 18

C.1.1 Air Quality........................................................................................................................ 18

C.1.2 Water Quality .................................................................................................................. 20

C.2 Seafloor Habitats and Biota......................................................................................................... 23

C.2.1 Soft Bottom Benthic Communities.................................................................................. 23

C.2.2 High‐Density Deepwater Benthic Communities.............................................................. 26

C.2.3 Designated Topographic Features................................................................................... 28

C.2.4 Pinnacle Trend Area Live Bottoms................................................................................... 28

C.2.5 Eastern Gulf Live Bottoms............................................................................................... 28

C.3 Threatened, Endangered, and Protected Species and Critical Habitat.......................................29

C.3.1 Sperm Whale (Endangered) ............................................................................................ 30

C.3.2 Florida Manatee (Endangered)........................................................................................ 33

C.3.3 Endangered Mysticete Whales........................................................................................ 35

C.3.4 Non‐Endangered Marine Mammals (Protected)............................................................. 35

C.3.5 Sea Turtles (Endangered/Threatened)............................................................................ 38

C.3.6 Piping Plover (Threatened).............................................................................................. 42
Contents

(Continued)

Page

Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page iii

C.3.7 Whooping Crane (Endangered)....................................................................................... 42

C.3.8 Gulf Sturgeon (Threatened)............................................................................................. 43

C.3.9 Beach Mice (Endangered)................................................................................................ 45

C.4 Coastal and Marine Birds ............................................................................................................ 46

C.4.1 Marine and Pelagic Birds................................................................................................. 46

C.4.2 Shorebirds and Coastal Nesting Birds.............................................................................. 49

C.5 Fisheries Resources..................................................................................................................... 51

C.5.1 Pelagic Communities and Ichthyoplankton..................................................................... 51

C.5.2 Essential Fish Habitat....................................................................................................... 53

C.6 Archaeological Resources............................................................................................................ 56

C.6.1 Shipwreck Sites................................................................................................................ 56

C.6.2 Prehistoric Archaeological Sites ...................................................................................... 57

C.7 Coastal Habitats and Protected Areas......................................................................................... 58

C.8 Socioeconomic and Other Resources.......................................................................................... 60

C.8.1 Recreational and Commercial Fishing ............................................................................. 60

C.8.2 Public Health and Safety.................................................................................................. 62

C.8.3 Employment and Infrastructure ...................................................................................... 63

C.8.4 Recreation and Tourism .................................................................................................. 64

C.8.5 Land Use .......................................................................................................................... 65

C.8.6 Other Marine Uses .......................................................................................................... 66

C.9 Cumulative Impacts..................................................................................................................... 67

C.9.1 Cumulative Impacts to Physical/Chemical Resources..................................................... 68

C.9.2 Cumulative Impacts to Biological Resources................................................................... 69

C.9.3 Cumulative Impacts to Socioeconomic Resources.......................................................... 71

D.  Environmental Hazards.........................................................................................72

D.1 Geologic Hazards......................................................................................................................... 72

D.2 Severe Weather........................................................................................................................... 72

D.3 Currents and Waves.................................................................................................................... 72

E.  Alternatives ..........................................................................................................72

F.  Mitigation Measures.............................................................................................73

G.  Consultation.........................................................................................................74

H.  Preparers..............................................................................................................74

I.  References.............................................................................................................74
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page iv

List of Tables

Table Page

1 Notices to Lessees and Operators (NTLs) that are referenced in this Environmental

Impact Analysis (EIA) ............................................................................................................. 4

2 Matrix of impact‐producing factors and affected environmental resources........................7

3 Conditional probabilities of a spill in the lease area contacting shoreline segments

(From: Ji et al., 2004)........................................................................................................... 14

4 Benthic community data from stations near the lease area and in similar water

depths sampled during the Northern Gulf of Mexico Continental Slope Habitats

and Benthic Ecology Study (From: Wei, 2006; Rowe and Kennicutt, 2009)........................23

5 Federally‐listed endangered and threatened species in the lease area and along

the northern Gulf Coast....................................................................................................... 29

List of Figures

Figure Page

1 Vicinity map for the lease area.............................................................................................. 2

2 Bathymetric map of the lease area showing proposed well surface locations...................17

3 Location of selected environmental features in relation to the lease area........................44
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page v

Acronyms and Abbreviations

ADIOS Automated Data Inquiry for Oil Spills

APD Application to Drill

ASI Airborne Support, Inc.

BOEMRE Bureau of Ocean Energy Management,

Regulation and Enforcement

bbl barrels

BOP blowout preventer

BPD barrels per day

CCA Clean Caribbean & Americas  

CFR Code of Federal Regulations

CGA Clean Gulf Associates

CH4 methane

CO carbon monoxide

CO2 carbon dioxide  

DP dynamically positioned

EA Environmental Assessment

EEZ Exclusive Economic Zone

EFH Essential Fish Habitat

EIA Environmental Impact Analysis

EIS Environmental Impact Statement

EP Exploration Plan

ESR enhanced surface renderings

ESA Endangered Species Act

FAD fish‐attracting device

GC Green Canyon

GMFMC Gulf of Mexico Fishery Management

Council

H2S hydrogen sulfide

HAPC Habitat Area of Particular Concern

HSE health, safety, and environment

IPF impact‐producing factor

ISO International Organization for

Standardization

MARPOL International Convention for the

Prevention of Pollution from Ships

MC Mississippi Canyon

MGD million gallons per day

MMBO million barrels of oil

MMPA Marine Mammal Protection Act

MMS Minerals Management Service

MSRC Marine Spill Response Corporation

MWCC Marine Well Containment Company

NAAQS National Ambient Air Quality Standards

NEPA National Environmental Policy Act

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric

Administration

NOx nitrogen oxides

NO2 nitrogen dioxide  

NPDES National Pollutant Discharge Elimination

System

NPS National Park Service

NRC National Research Council

NTL Notice to Lessees

NWR National Wildlife Refuge

OCS Outer Continental Shelf

OCSLA Outer Continental Shelf Lands Act

OSAT Operational Science Advisory Team

OSRA Oil Spill Risk Analysis

OSRL Oil Spill Response Limited

OSRP Oil Spill Response Plan

PAH polycyclic aromatic hydrocarbon

PM particulate matter

PSD Prevention of Significant Deterioration

ROV remotely operated vehicle

SBM synthetic‐based mud

Shell Shell Offshore Inc.

SOx sulfur oxides

SWSS Sperm Whale Seismic Study

TLP tension leg platform

U.S.C. United States Code

USCG U.S. Coast Guard

USDOI U.S. Department of the Interior

USEPA U.S. Environmental Protection Agency

VOC volatile organic compound

USFWS U.S. Fish and Wildlife Service

WCD worst case discharge

WCEP Whooping Crane Eastern Partnership

WMA Wildlife Management Area
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 1

Introduction

Project Summary

Shell Offshore Inc. (Shell) is submitting a Supplemental Exploration Plan (EP) for Mississippi

Canyon (MC) Block 807.  Shell’s Initial EP was approved by the Minerals Management Service

(MMS, now the Bureau of Ocean Energy Management, Regulation and Enforcement [BOEMRE])

on June 3, 1988.  Shell is now submitting a Supplemental EP for 24 proposed locations (batch set

wells A through X) in MC 807, located within 500 feet (ft) (152 meters [m])of one central

location.  On completion of the batch wells, one well will be drilled to total depth as MB01(A).  

This Supplemental EP also incorporates the revised blowout scenario and worst case discharge

(WCD) information as required by Notice to Lessees (NTL) 2010‐N06.

The lease area is 53 miles (85 km) from the nearest shoreline, 91 miles (146 kilometers [km])

from the onshore support base at Port Fourchon, Louisiana, and 82 miles (132 km) from the

helicopter base at Boothville, Louisiana (Figure 1).  All miles in this EIA are statute miles.  Water

depth at the wellsites is approximately 923 m (3,028 ft).

The Noble Bully I or a similar dynamically positioned (DP) drillship will be used for drilling.  

Drilling of wells will commence approximately November 1, 2011 and should be finished by the

first quarter of 2013.  The average time to batch set the wells will be either 10 or 15 days and it

is estimated to be 214 days to drill the MB01 (A).  

Purpose of the EIA

This Environmental Impact Analysis (EIA) was prepared pursuant to the requirements of the

Outer Continental Shelf Lands Act (OCSLA), 43 U.S.C. §§ 1331‐1356, and BOEMRE regulations,

including 30 CFR 250.212(o) and 250.227.  The EIA is a project‐ and site‐specific analysis of

Shell’s planned activities under this Supplemental EP.  The EIA also evaluates potential impacts

in accordance with NTL 2008‐G04 issued by the BOEMRE.   

The EIA presents data, analysis, and conclusions to support BOEMRE reviews as required by the

National Environmental Policy Act (NEPA) and other relevant Federal laws, including the

Endangered Species Act (ESA) and Marine Mammal Protection Act (MMPA), as the agency

considers this Supplemental EP for approval.  It also identifies the mitigation measures Shell will

implement in connection with the planned activities.

As specified in NTL 2008‐G04, an EIA is a project‐specific analysis that focuses on the impacts of

a specific plan.  This EIA addresses the impact‐producing factors (IPFs), resources, and impacts

associated with the activities proposed in this Supplemental EP including the drilling of wells.  

The EIA also incorporates the revised blowout scenario and WCD information required by

NTL 2010‐N06.
Mississippi Canyon Block 807 

Environmental Impact Analysis for Supplemental EP 

Figure 1. Vicinity map for the lease area.
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 3

The BOEMRE has performed numerous environmental evaluations of oil and gas activities on

the Gulf of Mexico Outer Continental Shelf (OCS).  Potential impacts were analyzed at a broader

level in the Programmatic Environmental Impact Statement (EIS) for the OCS Oil and Gas Leasing

Program (MMS, 2007a) and in recent multi‐lease‐sale EISs for the Western and Central Gulf of

Mexico Planning Areas (MMS, 2007b, 2008), as well as the Environmental Assessment (EA) for

Gulf of Mexico deepwater operations and activities (MMS, 2000) and a Grid EA for the Marco

Polo Development in Green Canyon (GC) 608 (Grid 13) (MMS, 2003).

These studies generated critical data and advanced the large body of existing knowledge of the

Gulf of Mexico OCS.  They analyze everything from potential impacts on the natural

environment to the socioeconomic effects of exploration and development activities.  They

include numerous technical studies ranging from the likely trajectory of spilled oil to the effects

of underwater noise on threatened and endangered species.  They inform agency

decision‐making on lease offerings, mitigation measures and lease stipulations, operational

requirements, and permit restrictions.  This substantial body of work, which in part forms the

basis for the evaluation presented here, will allow the BOEMRE and other regulatory agencies to

evaluate Shell’s Supplemental EP and ensure that oil and gas exploration and development

activities are performed in an environmentally sound manner, with minimal impacts on the

environment.  Shell has incorporated these comprehensive environmental analyses by reference

and built on them with project‐ and site‐specific analyses.

OCS Regulatory Framework

The regulatory framework for OCS activities in the Gulf of Mexico has been summarized by

MMS (2010).  Under the OCSLA, the U.S. Department of the Interior (USDOI) is responsible for

the administration of mineral exploration and development of the OCS.  Within the USDOI, the

BOEMRE is charged with the responsibility of managing and regulating the development of OCS

oil and gas resources in accordance with the provisions of the OCSLA.  The BOEMRE operating

regulations are in 30 CFR Parts 250, 251, and 254.

In implementing its responsibilities under the OCSLA and NEPA, the BOEMRE must consult

numerous Federal departments and agencies that have authority to govern and maintain ocean

resources pursuant to other Federal laws.  Among these are the U.S. Coast Guard (USCG),

U.S. Environmental Protection Agency (USEPA), U.S. Fish and Wildlife Service (USFWS), and the

National Oceanic and Atmospheric Administration (NOAA) through the National Marine

Fisheries Service (NMFS).  Federal regulations establish consultation and coordination processes

with Federal, State, and local agencies (e.g., the ESA, MMPA, Coastal Zone Management Act of

1972, and the Magnuson‐Stevens Fishery Conservation and Management Act).

NTLs are formal documents issued by the BOEMRE that provide clarification, description, or

interpretation of a regulation or standard; provide guidelines on implementing a special lease

stipulation or regional requirement; provide a better understanding of the scope and meaning

of a regulation by explaining the BOEMRE interpretation of a requirement; or transmit

administrative information such as current telephone listings or changes in the BOEMRE

personnel or office address.  Table 1 lists and summarizes the NTLs that are referenced in this

EIA.
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 4

Table 1. Notices to Lessees and Operators (NTLs) that are referenced in this Environmental

Impact Analysis (EIA).

NTL Title Summary

2010‐N10

Statement of Compliance with

Applicable Regulations and

Evaluation of Information

Demonstrating Adequate Spill

Response and Well Containment

Resources

Informs operators using subsea blowout preventers (BOPs) or

surface BOPs on floating facilities that applications for well permits

must include a statement signed by an authorized company official

stating that the operator will conduct all activities in compliance with

all applicable regulations, including the increased safety measures

regulations (75 FR 63346).  Informs operators that the BOEMRE will

be evaluating whether each operator has submitted adequate

information demonstrating that it has access to and can deploy

containment resources to promptly respond to a blowout or other

loss of well control.

2010‐N06

Information Requirements for

Exploration Plans, Development and

Production Plans, and Development

Operations Coordination Documents

on the OCS

Rescinds the limitations set forth in NTL 2008‐G04 regarding a

blowout scenario and worst case discharge scenario, and provides

guidance regarding the information required in blowout scenario and

worst case discharge scenario descriptions.

2009‐G40 Deepwater Benthic Communities

Guidance for avoiding and protecting high‐density deepwater

benthic communities (including chemosynthetic and deepwater coral

communities) from damage caused by Outer Continental Shelf (OCS)

oil and gas activities in water depths greater than 300 m (984 ft).  

Prescribes separation distances of 610 m (2,000 ft) from each mud

and cuttings discharge location and 76 m (250 ft) from all other

seafloor disturbances.

2009‐G39 Biologically‐Sensitive Underwater

Features and Areas

Guidance for avoiding and protecting biologically sensitive features

and areas (i.e., topographic features, pinnacles, low‐relief live

bottom areas, and other potentially sensitive biological features)

when conducting OCS operations in water depths less than 300 m

(984 ft) in the Gulf of Mexico.

2009‐G06 Military Warning and Water Test

Areas

Provides contact links to individual command headquarters for the

military warning and water test areas in the Gulf of Mexico.  Lease

stipulations require lessees or designated operators to enter into an

agreement with the appropriate individual military command

headquarters concerning the control of electromagnetic emissions

and use of boats and aircraft in the applicable warning area or water

test area before commencing such traffic.

2008‐G04

Information Requirements for

Exploration Plans and Development

Operations Coordination Documents

Guidance on the information requirements for OCS plans, including

EIA requirements and information regarding compliance with the

provisions of the Endangered Species Act and Marine Mammal

Protection Act.

2007‐G04

Vessel Strike Avoidance and

Injured/Dead Protected Species

Reporting

Recommends protected species identification training, recommends

that vessel operators and crews maintain a vigilant watch for marine

mammals and slow down or stop their vessel to avoid striking

protected species, and requires operators to report sightings of any

injured or dead protected species.

2007‐G03 Marine Trash and Debris Awareness

and Elimination

Instructs operators to exercise caution in the handling and disposal

of small items and packaging materials; requires the posting of

placards at prominent locations on offshore vessels and structures;

and mandates a yearly marine trash and debris awareness training

and certification process.

2005‐G07 Archaeological Resource Surveys

and Reports

Provides guidance on regulations regarding archaeological

discoveries, specifies requirements for archaeological resource

surveys and reports, and outlines options for protecting

archaeological resources.
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 5

Oil Spill Prevention and Contingency Planning

Shell submitted an update to the Gulf of Mexico Regional Oil Spill Response Plan (OSRP) to the

BOEMRE as a fundamental component of the planned drilling program on August 1, 2011.  The

OSRP certifies that Shell has the capability to respond, to the maximum extent practicable, to a

WCD (30 CFR 254.2).  The OSRP demonstrates Shell’s capabilities to rapidly and effectively

manage oil spills that may result from drilling operations.  Despite the extremely low likelihood

of a large oil spill event occurring during the project, Shell has designed its response program

based upon a regional capability of responding to a range of spill volumes that increase from

small operational spills up to and including a WCD from a well blowout.  Shell’s program meets

the response planning requirements of the relevant coastal states and Federal oil spill planning

regulations.  The OSRP includes information regarding Shell’s regional oil spill organization and

dedicated response assets, potential spill risks, and local environmental sensitivities.  The OSRP

presents specific information on the response program that includes a description of personnel

and equipment mobilization, the incident management team organization, and the strategies

and tactics used to implement effective and sustained spill containment and recovery

operations.

EIA Organization

The EIA is organized into Sections A through I corresponding to the information required by

NTL 2008‐G04, which provides guidance regarding information required by 30 CFR Part 250 for

EPs.  The main impact‐related discussions are in Section A (Impact‐Producing Factors) and

Section C (Impact Analysis).

   
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 6

A.  Impact‐Producing Factors

Table 2 is a matrix of IPFs and potentially affected environmental resources adapted from

Form MMS‐142.  An “X” indicates that an IPF could reasonably be expected to affect a certain

resource, and a dash (‐‐) indicates no impact or negligible impact.  Where there may be an

effect, an analysis is provided in Section C.  Potential IPFs for the proposed activity are listed

below and briefly discussed in the following subsections:

• Drillship presence (including noise and lights);

• Physical disturbance to the seafloor;

• Air pollutant emissions;

• Effluent discharges;

• Water intake;

• Onshore waste disposal;  

• Marine debris;

• Support vessel and helicopter traffic; and

• Accidents.

A.1 Drillship Presence (including noise and lights)

The wells will be drilled using the Noble Bully I or a similar drillship.  The drillship will be on site

for an estimated 457 days.  Two to four offshore support vessels will be in the vicinity of the

drillship to provide assistance as necessary.  The physical presence of a drillship in the ocean can

attract pelagic fishes and other marine life, as discussed in Section C.5.1.  DP drillships are

self‐propelled and maintain position over a well with a dynamic positioning system (computer

controlled thrusters).  

Drilling operations produce noise that includes strong tonal components at low frequencies,

including infrasonic frequencies in at least some cases (MMS, 2000).  According to Richardson

et al. (1995), more sound is generally radiated underwater from drillships during drilling

operations than from semisubmersibles, but this changes with the level of activity and age of

equipment on the vessel.  Drillships also maintain exterior lighting for navigational and aviation

safety in accordance with Federal regulations.

A.2 Physical Disturbance to the Seafloor

The DP drillship does not require the use of anchors for holding or stability purposes during

drilling operations.  As a result, there will be minimal physical disturbance to the seafloor due to

the presence of the drillship.  There will be minimal disturbance to soft bottom communities on

the seafloor during positioning of the wellbore and blowout preventers (BOP).  Physical

disturbance of the seafloor will be limited to the proximal area where the wellbore penetrates

the substrate, where mud and drill cuttings will be deposited.   
Mississippi Canyon Block 807 

Environmental Impact Analysis for Supplemental EP 

Table 2. Matrix of impact‐producing factors and affected environmental resources. X = potential impact; dash (‐‐) = no imp

Environmental Resources

Impact‐producing Factors

Drillship

Presence (incl.

noise & lights)

Physical

Disturbance

to Seafloor

Air

Pollutant

Emissions

Effluent

Discharges

WaterIntake

Onshore

Waste

Disposal

Marine

Debris

V

Physical/Chemical Environment

Air quality and greenhouse gases  ‐‐ ‐‐ X ‐‐ ‐‐  ‐‐ ‐‐ Water quality  ‐‐ ‐‐ ‐‐ X ‐‐  ‐‐ ‐‐ 

Seafloor Habitats and Biota

Soft bottom benthic communities  ‐‐ ‐‐ ‐‐ X ‐‐  ‐‐ ‐‐ High‐density deepwater benthic communities  ‐‐ ‐‐(4) ‐‐ ‐‐(4) ‐‐  ‐‐ ‐‐ Designated topographic features  ‐‐ ‐‐(1) ‐‐ ‐‐(1) ‐‐  ‐‐ ‐‐ Pinnacle trend area live bottoms  ‐‐ ‐‐(2) ‐‐ ‐‐(2) ‐‐  ‐‐ ‐‐ Eastern Gulf live bottoms  ‐‐ ‐‐(3) ‐‐ ‐‐(3) ‐‐  ‐‐ ‐‐ 

Threatened, Endangered, and Protected Species and Critical Habitat

Sperm whale (endangered) X(8) ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Florida manatee (endangered)  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Endangered mysticete whales ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Non‐endangeredmarinemammals(protected) X ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Sea turtles (endangered/threatened) X(8) ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Piping Plover (threatened)  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Whooping Crane (endangered)  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Gulf sturgeon (threatened)  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Beach mice (endangered) ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

Coastal and Marine Birds

Marine and pelagic birds X ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Shorebirds and coastal nesting birds  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

Fisheries Resources

Pelagic communities and ichthyoplankton X ‐‐ ‐‐ X X ‐‐ ‐‐ Essential Fish Habitat X ‐‐ ‐‐ X X  ‐‐ ‐‐ 

Archaeological Resources

Shipwreck sites  ‐‐ ‐‐(7) ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Prehistoric archaeological sites  ‐‐ ‐‐(7) ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

Coastal Habitats and Protected Areas

Beaches  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Wetlands and seagrass beds ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Coastal wildlife refuges and wilderness areas  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

Socioeconomic and Other Resources

Recreational and commercial fishing X ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Public health and safety  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Employment and infrastructure  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Recreation and tourism  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Land use ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Other marine uses  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 8

Table 2 Footnotes and Applicability:

(1) Activities that may affect a marine sanctuary or topographic feature.  Specifically, if the well, platform site, or

any anchors will be on the seafloor within the following:

(a) 4‐mi zone of the Flower Garden Banks, or the 3‐mi zone of Stetson Bank;

(b) 1,000‐m, 1‐mi, or 3‐mi zone of any topographic feature (submarine bank) protected by the Topographic

Features Stipulation attached to an Outer Continental Shelf (OCS) lease;

(c) Essential Fish Habitat (EFH) criteria of 500 ft from any no‐activity zone; or

(d) Proximity of any submarine bank (500‐ft buffer zone) with relief greater than 2 m that is not protected by

the Topographic Features Stipulation attached to an OCS lease.

• Not applicable.  The lease is not within or near any marine sanctuary, topographic feature, or

no‐activity zone.  There are no submarine banks in the blocks.

(2) Activities with any bottom disturbance within an OCS lease block protected through the Live Bottom (Pinnacle

Trend) Stipulation attached to an OCS lease.

• The Live Bottom (Pinnacle Trend) Stipulation is not applicable to the lease area.

(3) Activities within any Eastern Gulf OCS block where seafloor habitats are protected by the Live Bottom

(Low‐Relief) Stipulation attached to an OCS lease.  

• The Live Bottom (Low‐Relief) Stipulation is not applicable to the lease area.

(4) Activities on blocks designated by the BOEMRE as being in water depths 300 m or greater.

• No impacts on high‐density deepwater benthic communities are anticipated.  There are no features

indicative of high‐density chemosynthetic communities or coral communities within 610 m (2,000 ft) of

any drilling mud/cuttings discharge location. There will be no anchoring associated with the drilling

platform that could impact such communities if they were present.  

(5) Exploration or production activities where H2S concentrations greater than 500 ppm might be encountered.  

• Based on CFR 250.490(c), Shell is requesting that the BOEMRE classify the area as “H2S absent.”

(6) All activities that could result in an accidental spill of produced liquid hydrocarbons or diesel fuel that you

determine would impact these environmental resources.  If the proposed action is located a sufficient distance

from a resource that no impact would occur, the EIA can note that in a sentence or two.

• Accidental hydrocarbon spills could affect the resources marked (X) in the matrix, and impacts are

analyzed in Section C.

(7) All activities that involve seafloor disturbances, including anchor emplacements, in any OCS block designated

by the BOEMRE as having high‐probability for the occurrence of shipwrecks or prehistoric sites, including such

blocks that will be affected that are adjacent to the lease block in which your planned activity will occur.  If the

proposed activities are located a sufficient distance from a shipwreck or prehistoric site that no impact would

occur, the EIA can note that in a sentence or two.

• No impacts on archaeological resources are expected.  The lease area is on the list of high‐probability

blocks for shipwrecks.  The archaeological assessment for Block 807 and vicinity found 5,637 unidentified

sonar contacts.  However, the seafloor patterning and acoustic characteristics conclude that these are

modern debris.  The lease is well beyond the 60‐m depth contour used by the BOEMRE as the seaward

extent for prehistoric archaeological site potential in the Gulf of Mexico.

(8) All activities that you determine might have an adverse effect on endangered or threatened marine mammals

or sea turtles or their critical habitats.  

• IPFs that may affect marine mammals, sea turtles, or their critical habitats include drillship presence and

emissions, support vessel and helicopter traffic, and accidents.  See Section C.

(9) Production activities that involve transportation of produced fluids to shore using shuttle tankers or barges.

• Not applicable.   
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 9

A.3 Air Pollutant Emissions

Air pollutant emissions are estimated in Supplemental EP Section 8.  Offshore air pollutant

emissions will result from operations of the drillship, as well as service vessels and helicopters.  

These emissions occur mainly from combustion of diesel fuel.  The combustion of fuels occurs

on diesel‐powered generators, pumps, or motors and from lighter fuel motors.  Primary air

pollutants typically associated with OCS activities are suspended particulate matter (PM), sulfur

oxides (SOx), nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon monoxide

(CO).

The Air Quality Emissions Report prepared in accordance with BOEMRE requirements shows

that the projected emissions from emission sources associated with the well batch set

operations and MB01(A) drill at MC 807 meet the BOEMRE exemption criteria for all pollutants

except NOx.  Note that whereas the exemption criteria are based on NOx emissions, the modeled

significance level and the National Ambient Air Quality Standard (NAAQS) are dependent on

emissions of nitrogen dioxide (NO2) [30 CFR Part 250.303(e)]. For conservatism, all emissions of

NOx were assumed to be NO2 equivalent for modeling purposes.   

The well batch set operations and MB01(A) at MC 807 do not exceed the significant impact level

for the annual averaging period for NO2.  Since modeled NO2 concentrations are less than the

significant impact level for the NO2 annual NAAQS, no further action is required.  Additionally, as

modeled NO2 concentrations when combined with an appropriate background monitored value

are below the NO2 1‐hour NAAQS, no further action is required.  However, Shell will use low

sulfur fuel (0.05% by weight) to further reduce any possible impacts.

A.4 Effluent Discharges

Effluent discharges are summarized in Supplemental EP Section 7.  All offshore discharges will

be in accordance with the National Pollutant Discharge Elimination System (NPDES) General

Permit No. GMG290000 issued by the USEPA.  Discharges will be in compliance with and

monitored as required by the permit.

Water‐based drilling muds and cuttings will be released at the seafloor during the initial well

intervals before the marine riser is set that allows returns to the surface.  Excess cement slurry

also will be released at the seafloor during casing installation for the riserless portion of the

drilling operations.

A synthetic‐based mud (SBM) system will be used after the riser is installed.  Unused or residual

SBMs will be collected and transported to Port Fourchon, Louisiana for disposal in an approved

facility.  SBM cuttings will be discharged overboard after treatment that complies with the 6.9%

NPDES permit requirement for retention of the SBM fluid on cuttings.  The estimated volume of

SBM cuttings to be discharged is 1,714 barrels (bbl) for MB01(A).

Other effluent discharges in accordance with the NPDES permit will include excess cement,

non‐contact cooling water, treated sanitary and domestic wastes, deck drainage, desalination

unit brine, uncontaminated fire water, and ballast water.
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A.5 Water Intake

Seawater will be drawn via sea chests from the ocean for various services including cooling

water, ballasting water, and fire water.  The lineup of sea chests and pumps depends on

operating and sea conditions.  However, the overall seawater intake rates will typically range

from 5 million gallons per day (MGD) (normal operations) to 21 MGD (fire fighting).  

Section 316(b) of the Clean Water Act requires NPDES permits to ensure that the location,

design, construction, and capacity of cooling water intake structures reflect the best technology

available to minimize adverse environmental impact from impingement and entrainment of

aquatic organisms.  The current general NPDES Permit No. GMG 290000 does not specify

requirements for existing facilities (those that started construction before July 16, 2006).  The

Noble Bully I meets the applicability criteria for a “new” facility as defined by the NPDES permit

and therefore is subject to the cooling water intake permit requirements.  All affected intakes

will be in compliance with the design, monitoring, and recordkeeping requirements of the

NPDES permit.

A.6 Onshore Waste Disposal

Wastes generated during drilling are tabulated in Supplemental EP Section 7.  Volumes are

estimated to be 50 bbl/month.  Non‐hazardous trash and debris and non‐recyclable waste will

be transported to the Republic/BFI landfill in Sorrento, Louisiana or the parish landfill in

Avondale, Louisiana.  Additionally, nonhazardous recyclable waste will be recycled at Omega

Waste Management, Patterson, Louisiana or at ARC of New Iberia, New Iberia, Louisiana.  

Hazardous waste such as paints, solvents, and unused chemicals will be disposed of at Safety

Kleen Systems, Inc., Denton, Texas, while used oil will be sent to Omega Waste Management for

recycling, and glycol will be sent to Safety Kleen Systems, Inc for recycling.  Universal waste

including batteries, lamps, glass, and mercury‐contaminated waste will be recycled at Lamp

Environmental Industries, Hammond, Louisiana.  Oil filters, oily rags and pads, empty drums, and

cooking oil will be sent to Omega Waste Management, Patterson, Louisiana for recycling.  At the

onshore facilities, wastes will be recycled or disposed of according to all applicable regulations.

A.7 Marine Debris

Trash and debris released into the marine environment can harm marine mammals, turtles, and

birds through entanglement and ingestion.  Shell will adhere to the International Convention for

the Prevention of Pollution from Ships (MARPOL 73/78) Annex V requirements, USEPA and

USCG regulations, and MMS regulations and NTLs regarding solid wastes.  The BOEMRE

regulations at 30 CFR 250.300(a) and (b)(6) prohibit operators from deliberately discharging

containers and other similar materials (e.g., trash and debris) into the marine environment, and

30 CFR 250.300(c) requires durable identification markings on equipment, tools and containers

(especially drums), and other material.  USCG and USEPA regulations require operators to

become proactive in avoiding accidental loss of solid waste items by developing waste

management plans, posting informational placards, manifesting trash sent to shore, and using

special precautions such as covering outside trash bins to prevent accidental loss of solid waste.  

Shell complies with NTL 2007‐G03, which instructs operators to exercise caution in the handling

and disposal of small items and packaging materials, requires the posting of placards at

prominent locations on offshore vessels and structures, and mandates a yearly marine trash and
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debris awareness training and certification process.  Shell’s compliance with all applicable laws,

regulations, and NTL 2007‐G03 will avoid significant impacts on the environment.

A.8 Support Vessel and Helicopter Traffic

Shell will use existing shorebased facilities at Port Fourchon and Boothville, Louisiana, for onshore

support for water and air transportation, respectively.  No terminal expansion or construction is

planned at either location.

The supply base at Port Fourchon, Louisiana is operated by Shell and located on Bayou

LaFourche, approximately 3 miles (5 km) from the Gulf of Mexico.  During drilling, the project

will be supported by one crew boat and three offshore support vessels.  The crew boat will

make two round‐trips per week between the drilling facility and the onshore supply base, while

at least one support vessel will be in the field at all times.  The boats will normally move to the

project area via the most direct route from the shorebase.   

The air transportation base will be the PHI Heliport in Boothville, Louisiana.  A helicopter will make

one round‐trip daily between the drillship and the heliport.  The helicopter will be used to

transport personnel and small supplies and will normally take the most direct route of travel

between the helicopter base and the lease area when air traffic and weather conditions permit.  

Helicopters typically maintain a minimum altitude of 213 m (700 ft) while in transit offshore,

305 m (1,000 ft) over unpopulated areas or across coastlines, and 610 m (2,000 ft) over

populated areas and sensitive habitats such as wildlife refuges and park properties.

A.9 Accidents

A.9.1 Types of Accidents Evaluated

The analysis in this EIA focuses on two potential accidents:

• A small fuel spill, which is the most likely type of spill during OCS development activities; and

• An oil spill resulting from an uncontrolled blowout.  A blowout resulting in a large oil spill is

an extremely rare event, and the probability of such an event will be minimized by Shell’s

well control and blowout prevention measures as detailed in Supplemental EP Section 2j.   

The following subsections summarize assumptions about the sizes and fates of these spills, as

well as Shell’s spill response plans.  Impacts are analyzed in Section C.

The lease sale EIS (MMS, 2007b) analyzes three other types of accidents: chemical spills, vessel

collisions, and loss of well control.  These accidents are discussed briefly in Section A.9.4.

A.9.2 Small Fuel Spill

Spill Size.  According to the analysis in MMS (2007b), the most likely type of small spill

(<1,000 bbl) as a result of OCS activities is a minor diesel fuel spill.  Historically, most diesel spills

have been <1 bbl, and this size is predicted to be the most common in ongoing and future

OCS activities in the Western and Central Gulf of Mexico Planning Areas (MMS, 2007b).  The

average size for spills <1 bbl is 0.07 bbl, and the median size for spills of 1 to 10 bbl is 3 bbl

(MMS, 2007b).  For this analysis, a small diesel fuel spill of 3 bbl is assumed.  Operational

experience suggests that the most likely cause of such a spill would be a hose rupture resulting

in the loss of the contents of a fuel transfer hose, which is less than 3 bbl.
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Spill Fate.  The fate of a small fuel spill in the lease area would depend on meteorological and

oceanographic conditions at the time, as well as the effectiveness of spill response activities.  

However, given the open ocean location of the lease area, the duration of a small spill and the

opportunity for impacts to occur would be very brief.

The water‐soluble fractions of diesel are dominated by two‐ and three‐ringed polycyclic

aromatic hydrocarbons (PAHs), which are moderately volatile (National Research Council [NRC],

2003).  The constituents of these oils are light to intermediate in molecular weight and can be

readily degraded by aerobic microbial oxidation.  Diesel’s density is such that it will not sink and

pool on the seafloor.  Diesel dispersed in the water column can adhere to suspended sediments,

but this generally occurs only in coastal areas with high suspended solids loads (NRC, 2003) and

would not be expected to occur to any appreciable degree in offshore waters of the Gulf of

Mexico.  Diesel oil is readily and completely degraded by naturally occurring microbes

(NOAA, 2006).

The fate of a small diesel fuel spill was estimated using NOAA’s ADIOS2 (Automated Data Inquiry

for Oil Spills) model.  This model uses the physical properties of oils in its database to predict the

rate of evaporation and dispersion over time, as well as changes in the density, viscosity, and

water content of the product spilled.  It is estimated that over 90% of a small diesel spill would

be evaporated or dispersed within 24 hours.  The area of the sea surface with diesel fuel on it

would range from 0.5 to 5 ha (1.2 to 12 ac) depending on sea state and weather conditions.

The ADIOS2 results, coupled with spill trajectory information discussed below for a large spill,

indicate that a small fuel spill would not have any impacts on coastal or shoreline resources.  

The lease area is 53 miles (85 km) from the nearest shoreline (Louisiana).  Modeling results

discussed below indicate that a spill in the lease area would have a 4% probability of contacting

the nearest Louisiana shoreline (Plaquemines Parish) within 10 days after a spill.  By this time,

essentially 100% of a small fuel spill would have been dispersed or evaporated by natural

processes, even if no response measures were implemented.  MMS (2007b) similarly concluded

that spills <1,000 bbl are not expected to persist as a slick on the surface of the water beyond a

few days and are unlikely to make landfall or reach coastal waters prior to breaking up.  MMS

(2007b) noted that this conclusion is supported by a previous analysis of 3‐day trajectory model

runs, previous weathering analyses, and historical records of spill incidents.

Spill Response.  In the unlikely event of a fuel spill, response equipment and trained personnel

would be available to ensure that any spill effects are localized and would result only in

short‐term environmental consequences.  Supplemental EP Section 9b provides a detailed

discussion of Shell’s response to a spill.

A.9.3 Large Oil Spill

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  Blowouts are rare events and most do not result in oil spills.  

Holand (1997) estimated a probability of 0.0021 for a deep drilling blowout during exploration

drilling based on U.S. Gulf of Mexico data.  An updated analysis using the SINTEF database

estimates a blowout frequency of 0.0017 per exploration well for non‐North Sea locations

(International Association of Oil & Gas Producers, 2010).  As noted by MMS (2007b), from 1992
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to 2005, half of blowouts lasted less than half a day, and fewer than 10% of blowouts resulted in

spilled oil.

The risk of a blowout during this project is significantly lower than indicated by these statistics

because the well design and drilling program were developed using information gathered during

the drilling of previous wells in MC 807.  During drilling of previous wells, the reservoirs were

fully logged and evaluated.  Substantial data associated with the reservoirs were gathered

including core, pressure, and fluid data.  Data gained during these earlier operations provide

substantial information that was used in preparing for the proposed operation.  

Spill Size.  Shell has calculated a WCD for this Supplemental EP, using the requirements

prescribed by NTL 2010‐N06, as 465,000 BPD for the first day with a 30‐day average of

365,000 BPD.  The detailed analysis of this calculation can be found in

Supplemental EP Section 2j.  The WCD scenario for this Supplemental EP, in terms of both initial

and sustained rates, has a low probability of being realized.  Some of the factors that are likely

to reduce rates and volumes, and are not included in the WCD calculation, include obstructions

or equipment in the wellbore, well bridging, and early intervention such as containment

capabilities.

Shell has a robust system in place to prevent blowouts.  Included in Supplemental EP Sections 2j

and 9b is Shell’s response to NTL 2010‐N06, which includes descriptions of measures to prevent

a blowout, reduce the likelihood of a blowout, and conduct effective and early intervention in

the event of a blowout.  Shell will also comply with NTL 2010‐N10 and the Interim Final Drilling

Safety Rule, which specify additional safety measures for OCS activities.

Spill Trajectory.  The fate of a large oil spill in the lease area would depend on meteorological

and oceanographic conditions at the time.  The Oil Spill Risk Analysis (OSRA) model is a

computer simulation of oil spill transport that uses realistic data for winds and currents to

predict spill fate.  The OSRA report by Ji et al. (2004) provides conditional contact probabilities

for shoreline segments.  The results for Launch Area 58 (where MC 807 is located) are presented

in Table 3.  The model predicts no shoreline contacts within 3 days.  After 10 days, three

Louisiana parishes may be contacted.  After 30 days, 11 counties and parishes from Texas to the

Florida Panhandle may be contacted.  Plaquemines Parish, Louisiana has the greatest probability

of shoreline contact, with a 4% and 8% chance within 10 and 30 days, respectively.

The OSRA model does not evaluate the fate of a spill over time periods longer than 30 days, nor

does it predict the fate of a release that continues over a period of weeks or months.  Also as

noted by Ji et al. (2004), the OSRA model does not take into account the chemical composition

or biological weathering of oil spills, the spreading and splitting of oil spills, or spill response

activities.  The model does not assume a particular spill size but has generally been used by the

BOEMRE to evaluate contact probabilities for spills greater than 1,000 bbl.
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Table 3. Conditional probabilities of a spill in the lease area contacting shoreline segments

(From: Ji et al., 2004).  Values are conditional probabilities that a hypothetical spill in

the lease area (represented by Oil Spill Risk Analysis Launch Area 58) could contact

shoreline segments within 3, 10, or 30 days.

Shoreline

Segment County or Parish and State Conditional Probability of Contacta (%)

3 Days 10 Days 30 Days

C10 Galveston, Texas ‐‐ ‐‐ 1

C12 Jefferson, Texas ‐‐ ‐‐ 1

C13 Cameron, Louisiana ‐‐ ‐‐ 3

C14 Vermilion, Louisiana ‐‐ ‐‐ 2

C15 Iberia, Louisiana ‐‐ ‐‐ 1

C17 Terrebonne, Louisiana ‐‐ 1 3

C18 Lafourche, Louisiana ‐‐ 2 3

C19 Jefferson, Louisiana ‐‐ ‐‐ 1

C20 Plaquemines, Louisiana ‐‐ 4 8

C21 St. Bernard, Louisiana ‐‐ ‐‐ 1

C28 Okaloosa, Florida ‐‐ ‐‐ 1

a Conditional probability refers to the probability of contact within the stated time period, assuming that a spill has

occurred (‐‐ indicates less than 0.5%).

Weathering.  Following an oil spill, several physical, chemical, and biological processes,

collectively called weathering, interact to change the physical and chemical properties of the oil,

and thereby influence its harmful effects on marine organisms and ecosystems.  The most

important weathering processes include spreading, evaporation, dissolution, dispersion into the

water column, formation of water‐in‐oil emulsions, photochemical oxidation, microbial

degradation, adsorption to suspended particulate matter, and stranding on shore or

sedimentation to the seafloor (NRC, 2003).

Weathering decreases the concentration of oil and produces changes in its chemical

composition, physical properties, and toxicity.  The more toxic, light aromatic and aliphatic

hydrocarbons are lost rapidly by evaporation and dissolution from the slick on the water

surface.  Evaporated hydrocarbons are degraded rapidly by sunlight.  Biodegradation of oil on

the water surface and in the water column by marine bacteria removes first the n‐alkanes and

then the light aromatics from the oil.  Other petroleum components are biodegraded more

slowly.  Photooxidation attacks mainly the medium and high molecular weight PAHs in the oil on

the water surface.

Spill Response.  Shell is a founding member of the Marine Well Containment Company (MWCC)

and has access to an integrated subsea well control and containment system that can be rapidly

deployed through the MWCC.  The MWCC is a non‐profit organization that assists with the

subsea containment system during a response.  The near‐term containment response capability

will be specifically addressed in Shell’s NTL 2010‐N10 submission at the time an Application to

Drill (APD) is submitted and will include equipment and services available to Shell through

MWCC’s development of near‐term capability and other industry sources.  Shell is a member of

Clean Caribbean & Americas (CCA), Marine Spill Response Corporation (MSRC), Clean Gulf

Associates (CGA), and Oil Spill Response Limited (OSRL), organizations that are committed to

providing the resources necessary to respond to a spill as outlined in Shell’s Regional OSRP

(August 2011).  
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The experience of gaining control over the Macondo well has resulted in a better understanding

of the necessary equipment and systems for well containment.  As a result, industry and

government are better equipped and prepared today to contain an oil well blowout in

deepwater (see page 17 of the Decision Memorandum dated October 1, 2010 [Bromwich,

2010]).  Shell is further analyzing these advances and incorporating them into its comprehensive

approach to help prevent and, if needed, control another deepwater control incident.  Shell is

also investing in research and development to improve containment systems.  

The primary offshore response would involve mechanical recovery.  The primary response

equipment that would be mobilized to the spill location for spills in normal and adverse weather

conditions is included in the Offshore On‐Water Recovery Activation List in the OSRP.

Chemical dispersion capabilities are also readily available from resources such as MSRC at

Stennis, Mississippi, and Coolidge, Arizona; CGA/Airborne Support, Inc. (ASI) in Houma,

Louisiana; Oil Spill Response in South Hampton, UK and Singapore; and CCA in Ft. Lauderdale,

Florida.  Available equipment for surface and subsea application of dispersants, response times,

and support resources are identified in the OSRP.

Open‐water in situ burning may also be used as a response strategy, depending on the

circumstances of the release.  If appropriate conditions exist and approval from the Unified

Command is received, one or multiple in situ burning task forces could be deployed offshore.

See Supplemental EP Sections 2j and 9b for a detailed description of Shell’s site‐specific

response to the worst case spill for this plan.  These sections, along with Shell’s OSRP, also

include a description of surface and subsea containment capabilities that could be implemented

in the event of the worst case spill at this site.

A.9.4 Other Accidents Not Analyzed in Detail

The lease sale EIS (MMS, 2007b) discusses three other types of accidents: chemical spills, vessel

collisions, and loss of well control.  These accidents are discussed briefly below. No hydrogen

sulfide (H2S) occurs at this site, and no other site‐specific issues have been identified for this

Supplemental EP.  The analysis in the lease sale EIS for these topics is incorporated by reference.

Chemical Spill.  Chemicals are used in drilling operations to achieve technical goals in the drilling

process, improve the efficiency and safety of drilling, and protect associated equipment.  

Chemicals used during exploration and drilling include surfactants, bentonite clays, olefins,

inorganic salts, glycols, polymers, barite, and calcium carbonate.  Supplies are renewed on a

regular basis by transfer in containers from supply boats (Boehm et al., 2001).  In addition to

chemicals used in drilling fluids, the following chemicals are likely to be used on the drilling rig or

drillship: ethylene glycol (blowout prevention control fluid, used in closed cooling loops for

crane and main engines and brake coolers), cement (used to cement casing in place), solvents

(used in painting operations), hydraulic fluids (used in cranes and other hydraulic rig

equipment), lubricating oil and grease (used in reciprocating and electrical equipment), and

sodium hypochlorite (dilute, used as laundry bleach and disinfectant).

A study of environmental risks of chemical products used in OCS activities determined that only

two chemicals could potentially affect the marine environment: zinc bromide and ammonium

chloride (Boehm et al., 2001).  The risk of a spill for these chemicals is very low.  Most other
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chemicals are either nontoxic or used in small quantities.  No significant impacts are expected

from chemical spills.

Vessel Collisions.  As summarized in MMS (2007b), vessel collisions occasionally occur during

routine operations.  Most collision mishaps are the result of service vessels colliding with

platforms or vessel collisions with pipeline risers.  Some of these collisions have caused spills of

diesel fuel or chemicals.  Shell will comply with all USCG and BOEMRE‐mandated safety

requirements to minimize the potential for vessel collisions.

Loss of Well Control.  A loss of well control is the uncontrolled flow of a reservoir fluid that may

result in the release of gas, condensate, oil, drilling fluids, sand, or water.  Loss of well control is

a broad term that includes minor to serious well control incidents, while blowouts are

considered to be a subset of more serious incidents with greater risk of oil spill or human injury

(MMS, 2007b).  Loss of well control may result in the release of synthetic drilling fluid or loss of

oil.  Shell has a robust system in place to prevent loss of well control.  Included in this

Supplemental EP is Shell’s response to NTL 2010‐N06, which includes descriptions of measures

to prevent a blowout, reduce the likelihood of a blowout, and conduct effective and early

intervention in the event of a blowout.  Shell will also comply with NTL 2010‐N10 and the

Interim Final Drilling Safety Rule, which specify additional safety measures for OCS activities.  

See Supplemental EP Sections 2j and 9b for further information.

H2S Release.  Based on CFR 250.490(c), Shell requests that the Regional Supervisor, Field

Operations, classify the area in the proposed drilling operations as an area where the absence of

H2S has been confirmed.

B.  Affected Environment

The lease area is in the north‐central Gulf of Mexico, 53 miles (85 km) from the nearest

shoreline (Louisiana), 91 miles (146 km) from the onshore support base at Port Fourchon,

Louisiana, and 82 miles (132 km) from the helicopter base at Boothville, Louisiana (Figure 1).

The wellsites are in an area of level seafloor where the water depth is approximately 923 m

(3,028 ft) (Figure 2).  The side scan sonar survey confirmed the existence of man‐made

infrastructure including several flowlines and umbilicals in the project area (C&C Technologies,

Inc., 2009).  There will be no interference with this infrastructure and any previously drilled

wellsites in MC 807 from the proposed exploration drilling activity.  The new wells, A through X,

will be positioned approximately 488 m (1,600 ft) southwest of Shell’s Europa flowlines and

umbilicals.  A 500 ft avoidance zone will be placed around all flowlines and umbilicals

(C&C Technologies, Inc., 2009) and there will be no interference with any previously drilled

wellsites.

Based on a high‐resolution geophysical survey, consisting of frequency enhanced 3‐D seismic,

enhanced surface renderings (ESR), ESRs with amplitudes applied, and autonomous underwater

vehicle high‐resolution data, the geohazards assessment concluded that MC 807 proposed

locations A through X appear suitable for the planned activity.
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A detailed description of the regional affected environment is provided in recent EISs

(MMS, 2007b, 2008), including meteorology, oceanography, geology, air and water quality,

benthic communities, threatened and endangered species, biologically sensitive resources,

archaeological resources, socioeconomic conditions, and other marine uses.  These regional

descriptions are based on extensive literature reviews and are incorporated by reference.  

General background information is presented below, and brief descriptions of each potentially

affected resource are presented in Section C, including site‐specific and/or new information if

available.

Figure 2. Bathymetric map of the lease area showing proposed well surface locations.
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The local environment in the lease area is not known to be unique with respect to

physical/chemical, biological, or socioeconomic conditions.  Baseline environmental conditions

in the lease area are expected to be consistent with the regional description of continental slope

locations evaluated in recent lease sale EISs (MMS, 2007b, 2008).

The lease area is approximately 64 miles (103 km) southwest of the Macondo spill site.  Based

on an analysis of satellite imagery (ESRI, 2010), the surface slick extended over the lease area at

various times prior to capping of the well; therefore, existing water quality in the lease area

could have been temporarily affected.  Macondo spill impacts are addressed in Section C.9

(Cumulative Impacts) where available and applicable.

C.  Impact Analysis

This section analyses the potential direct and indirect impacts of routine activities and accidents.  

Cumulative impacts are discussed in Section C.9.

Impacts have been analyzed extensively in recent multi‐lease‐sale EISs for the Western and

Central Gulf of Mexico Planning Areas (MMS, 2007b, 2008) as well as the EA for Gulf of Mexico

deepwater operations and activities (MMS, 2000) and a Grid EA for the Marco Polo

Development in GC 608 (MMS, 2003).  Site‐specific issues are addressed in this section as

appropriate.

C.1 Physical/Chemical Environment

C.1.1 Air Quality

There are no site‐specific air quality data for the project area.  Due to the distance from

shorebased pollution sources, offshore air quality is expected to be good.  The attainment status

of Federal OCS waters is unclassified because there is no provision in the Clean Air Act for

classification of areas outside State waters (MMS, 2007b).

As of April 21, 2011, all Louisiana, Mississippi, Alabama, and Florida coastal counties and

parishes are in attainment of the NAAQS for all criteria pollutants (USEPA, 2011).  Two

metropolitan areas in Texas are nonattainment areas for 8‐h ozone (Dallas‐Fort Worth and

Houston‐Brazoria), and El Paso County is a nonattainment area for PM10 (USEPA, 2011).  Winds

in the region are driven by the clockwise circulation around the Bermuda High (MMS, 2007b).  

The Gulf of Mexico is located to the southwest of this center of circulation, resulting in a

prevailing southeasterly to southerly flow, which is conducive to transporting emissions toward

shore.  However, circulation is also affected by tropical cyclones (hurricanes) during summer and

fall, and by extratropical cyclones (cold fronts) during winter.

IPFs potentially affecting air quality are air pollutant emissions and two types of accidents:

a small fuel spill and a large oil spill.

Impacts of Air Pollutant Emissions

Air pollutant emissions are the only routine IPF likely to affect air quality.  Offshore air pollutant

emissions will result from the operation of the drilling rig or drillship, as well as helicopters and
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service vessels.  These emissions occur mainly from combustion or burning of diesel fuel.  The

combustion of fuels occurs primarily on diesel‐powered generators, pumps, or motors and from

lighter fuel motors.  Primary air pollutants typically associated with OCS activities are suspended

PM, SOx, NOx, VOCs, and CO.

Due to the distance from shore, routine operations in the project area are not expected to have

any impact on air quality conditions along the coast, including nonattainment areas.  As noted in

the lease sale EIS (MMS, 2007b), emissions of air pollutants from routine activities in the Central

Gulf of Mexico Planning Area are projected to have minimal impacts to onshore air quality

because of the prevailing atmospheric conditions, emission heights, emission rates, and the

distance of these emissions from the coastline.   

The Air Quality Emissions Report (see Supplemental EP Section 8) prepared in accordance with

BOEMRE requirements shows that the projected emissions from emission sources associated

with the well batch set operations and MB01(A) at MC 807 meet the BOEMRE exemption

criteria for PM, SOx, VOCs and CO, but not for NOx.  Note that whereas the exemption criteria

are based on NOx emissions, the modeled significance level and the NAAQS are dependent on

emissions of nitrogen dioxide (NO2) [30 CFR Part 250.303(e)]. For conservatism, all emissions of

NOx were assumed to be NO2 equivalent for modeling purposes.   

The well batch set operations and MB01(A) at MC 807 do not exceed the significant impact level

for the annual averaging period for NO2.  Since modeled NO2 concentrations are less than the

significant impact level for the NO2 annual NAAQS, no further action is required.  Additionally, as

modeled NO2 concentrations when combined with an appropriate background monitored value

are below the NO2 1‐hour NAAQS, no further action is required.  However, Shell will use low

sulfur fuel (0.05% by weight) to further reduce any possible impacts.

The Breton Wilderness Area, which is part of the Breton National Wildlife Refuge (NWR), is

designated under the Clean Air Act as a Prevention of Significant Deterioration (PSD) Class I air

quality area.  The BOEMRE coordinates with the National Park Service (NPS) and the USFWS if

emissions from proposed projects may affect the Breton Class I area.  Additional review and

mitigation measures may be required for sources within 186 miles (300 km) of the Breton Class I

area that exceed emission limits agreed upon by the administering agencies (NPS, 2010).  The

lease area is approximately 90 miles (145 km) from the Breton Wilderness Area.  Shell does not

anticipate any impact on the Class I area but will comply with any emissions requirements as

directed by the BOEMRE.

Impacts of a Small Fuel Spill

Potential impacts of a small spill on air quality are expected to be consistent with those analyzed

and discussed in recent EISs (MMS, 2007b, 2008).  The probability of a small spill would be

minimized by Shell’s preventative measures during routine operations, including fuel transfer.  

In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the

impacts.  Supplemental EP Sections 2j and 9b provide detail on spill response measures.  Given

the open ocean location of the lease area, the extent and duration of air quality impacts from a

small spill would not be significant.

A small fuel spill would affect air quality near the spill site by introducing VOCs through

evaporation.  The ADIOS2 model (see Section A.9.2) indicates that more than 90% of a small

diesel spill would be evaporated or dispersed within 24 hours.  The area of the sea surface with
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diesel fuel on it would range from 0.5 to 5 ha (1.2 to 12 ac) depending on sea state and weather

conditions.

A small fuel spill would not affect coastal air quality because the spill would not be expected to

make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill

Potential impacts of a large oil spill on air quality are expected to be consistent with those

analyzed and discussed in recent EISs (MMS, 2007b, 2008).  

A large oil spill would affect air quality by introducing VOCs through evaporation from the slick.  

The extent and persistence of impacts would depend on the meteorological and oceanographic

conditions at the time and the effectiveness of spill response measures.  Additional air quality

impacts could occur if response measures included in situ burning of the floating oil.  Burning

would generate a plume of black smoke and result in emissions of NOx, SOx, CO, and PM, as well

as greenhouse gases.

Due to the lease area location (53 miles [85 km] from the nearest shoreline), most air quality

impacts would occur in offshore waters.  Depending on the spill trajectory and the effectiveness

of spill response measures, coastal air quality could also be affected.  Based on the OSRA

modeling predictions (Table 3), Plaquemines Parish, Louisiana, is the coastal area most likely to

be affected.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on air quality are expected.

C.1.2 Water Quality

There are no site‐specific water quality data for the lease area.  Due to the lease location in

deep, offshore waters, water quality is expected to be good, with low levels of contaminants.  As

noted in the lease sale EIS (MMS, 2007b), deepwater areas in the northern Gulf of Mexico are

relatively homogeneous with respect to temperature, salinity, and oxygen.  Kennicutt (2000)

noted that the deepwater region has little evidence of contaminants in the dissolved or

particulate phases of the water column.  However, there are localized occurrences of natural

seepage of oil, gas, and brines in near‐surface sediments and up through the water column.

The lease area is approximately 64 miles (103 km) southwest of the Macondo spill site.  Based

on satellite imagery (ESRI, 2010), the surface slick extended over the lease area during the spill,

and therefore existing water quality in the lease area could have been temporarily affected.  The

Operational Science Advisory Team (OSAT, 2010) reported that after August 2010, waters and

sediments in the deepwater Gulf of Mexico beyond 1.8 miles (3 km) from the Macondo wellsite

were below USEPA acute and chronic benchmarks for PAHs and were not hypoxic.  These

observations indicate that baseline environmental conditions in the lease area are unlikely to

have been significantly altered by the spill.

IPFs potentially affecting water quality are effluent discharges and two types of accidents:

a small fuel spill and a large oil spill.
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Environmental Impact Analysis for Supplemental EP Page 21

Impacts of Effluent Discharges

Discharges of treated SBM cuttings will produce temporary, localized increases in suspended

solids in the water column around the drilling rig or drillship.  In general, turbid water can be

expected to extend between a few hundred meters and several kilometers down current from

the discharge point (NRC, 1983; Neff, 1987).  All NPDES permit limitations and requirements will

be met.  After discharge, SBM retained on cuttings would be expected to adhere tightly to the

cuttings particles and, consequently, would not produce much turbidity as the cuttings sink

through the water column (Neff et al., 2000).  There will be no persistent impacts on water

quality in the lease area.

Treated sanitary and domestic wastes may have a slight transient effect on water quality in the

immediate vicinity of these discharges.  All NPDES permit limitations and requirements will be

met and little or no impact on water quality is anticipated.

Deck drainage includes all effluents resulting from rain, deck washings, and runoff from curbs,

gutters, and drains, including drip pans in work areas.  Rainwater that falls on uncontaminated

areas of the drilling rig or drillship will flow overboard without treatment.  However, rainwater

that falls on the drilling rig or drillship deck and other areas such as chemical storage areas and

places where equipment is exposed will be collected and oil and water separated to meet

NPDES permit requirements.  Little or no impact on water quality is anticipated.

Other discharges in accordance with the NPDES permit, such as desalination unit brine and

uncontaminated cooling water, fire water, and ballast water are expected to be diluted rapidly

and have little or no impact on water quality.

Support vessels will discharge treated sanitary and domestic wastes.  These will have a slight

effect on water quality in the immediate vicinity of the discharges.  All support vessel discharges

will be in accordance with USCG regulations and, as applicable, the NPDES Vessel General

Permit, and therefore are not expected to cause significant impacts on water quality.

Impacts of a Small Fuel Spill

Potential impacts of a small spill on water quality are expected to be consistent with those

analyzed and discussed in recent EISs (MMS, 2007b, 2008).  The probability of a small spill would

be minimized by Shell’s preventative measures during routine operations, including fuel

transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill response measures.  

Given the open ocean location of the lease area, the extent and duration of water quality

impacts from a small spill would not be significant.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  However, it is estimated that more

than 90% of a small diesel spill would be evaporated or dispersed within 24 hours

(see Section A.9.2).  The area of the sea surface with diesel fuel on it would range from

0.5 to 5 ha (1.2 to 12 ac) depending on sea state and weather conditions.
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Environmental Impact Analysis for Supplemental EP Page 22

The water‐soluble fractions of diesel are dominated by two‐ and three‐ringed PAHs, which are

moderately volatile (NRC, 2003).  The constituents of these oils are light to intermediate in

molecular weight and can be readily degraded by aerobic microbial oxidation.  Diesel’s density is

such that it will not sink and pool on the seafloor.  Diesel dispersed in the water column can

adhere to suspended sediments, but this generally occurs only in coastal areas with high

suspended solid loads (NRC, 2003) and would not be expected to occur to any appreciable

degree in offshore waters of the Gulf of Mexico.  Diesel oil is readily and completely degraded

by naturally occurring microbes (NOAA, 2006).

A small fuel spill would not affect coastal water quality because the spill would not be expected

to make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill

Potential impacts of a large oil spill on water quality are expected to be consistent with those

analyzed and discussed in recent EISs (MMS, 2007b, 2008).  A large spill would affect water

quality by producing a slick on the water surface and increasing the concentrations of petroleum

hydrocarbons and their degradation products.  The extent and persistence of impacts would

depend on the meteorological and oceanographic conditions at the time and the effectiveness

of spill response measures.  Most of the oil would be expected to form a slick at the surface,

although new information from the Macondo spill indicates that plumes of submerged oil

droplets can be produced when subsea dispersants are applied at the wellhead (Camilli et al.,

2010; Hazen et al., 2010; Joint Analysis Group, 2010a,b,c).  A report by Kujawinski et al. (2011)

indicates that chemical components of subsea dispersants used during the Macondo spill

persisted for up to two months and were detectable up to 186 miles (300 km) from the wellsite

at a water depth of 1,000 to 1,200 m (3,280 to 3,937 ft).   

Once oil enters the ocean, a variety of physical, chemical, and biological processes acts to

disperse the oil slick.  These processes include spreading, evaporation of the more volatile

constituents, dissolution into the water column, emulsification of small droplets, agglomeration

sinking, microbial modification, photochemical modification, and biological ingestion and

excretion (NRC, 2003).  Marine water quality would be temporarily affected by the dissolved

components and small oil droplets that do not rise to the surface or are mixed down by surface

turbulence.  Dispersion by currents and microbial degradation removes the oil from the water

column or dilutes the constituents to background levels.

A large oil spill could result in a release of gaseous hydrocarbons that could affect water quality.  

During the Macondo spill, large volumes of methane (CH4) were released, causing localized

oxygen depletion as methanotrophic bacteria rapidly metabolized the hydrocarbons (Joye et al.,

2011; Kessler et al., 2011).  However, a broader study of the deepwater Gulf of Mexico found

that although some stations showed had a slight depression of dissolved oxygen relative to

climatological background values, the findings were not indicative of hypoxia (OSAT, 2010).  

Stations revisited around the Macondo wellhead in October 2010 showed no measurable

oxygen depressions (OSAT, 2010).

Due to the lease area location (53 miles [85 km] from the nearest shoreline), most water quality

impacts would occur in offshore waters.  Depending on the spill trajectory and the effectiveness

of spill response measures, coastal water quality could be affected.  Based on the OSRA
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Environmental Impact Analysis for Supplemental EP Page 23

modeling predictions (Table 3), nearshore waters and embayments of Plaquemines Parish,

Louisiana, are the most likely coastal areas where water quality could be affected.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on water quality are expected.

C.2 Seafloor Habitats and Biota

Water depth at the proposed well surface locations is approximately 923 m (3,028 ft).  The

seafloor is expected to consist mainly of soft bottom.  The chemosynthetic community

assessment based on the hazards report by C&C Technologies, Inc. (2009) did not identify any

features that could support high‐density deepwater benthic communities within 610 m

(2,000 ft) of the wellsites.  See Supplemental EP Section 6a for further information.

According to the BOEMRE (2011), existing information for the deepwater Gulf of Mexico

indicates that the seafloor is composed primarily of soft sediments; hard bottom communities

are rare.  MC 807 is within deepwater Grid 13, and the BOEMRE website indicates that remotely

operated vehicle (ROV) coverage of the seafloor in this grid is adequate to characterize the area.

C.2.1 Soft Bottom Benthic Communities

Data from the recent Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology

study (Wei, 2006; Rowe and Kennicutt, 2009) can be used to describe typical benthic

communities in the area.  Table 4 summarizes data from two nearby stations in similar water

depths.  Sediments at these two stations were predominantly clay (46% to 54%) and silt

(43% to 45%).

Table 4. Benthic community data from stations near the lease area and in similar water depths

sampled during the Northern Gulf of Mexico Continental Slope Habitats and Benthic

Ecology Study (From: Wei, 2006; Rowe and Kennicutt, 2009).

Station

Location

Relative to

Lease Area

Water Depth

(m)

Abundance

Meiofauna

(individuals/m2)

Macroinfauna

(individuals/m2)

Megafauna

(individuals/ha)

MT‐3 17 mi NW 987 885,995 4,924 1,034

MT‐4 23 mi SSW 1,401 246,058 3,262 1,548

Meiofaunal and megafaunal abundance from Rowe and Kennicutt (2009); macroinfaunal abundance from Wei

(2006).

Meiofauna (animals passing through a 0.5‐mm sieve but retained on a 0.062‐mm sieve)

densities in water depths representative of the lease area typically range from about

250,000 to 650,000 individuals/m2 (Rowe and Kennicutt, 2009).  Nematodes, nauplii, and

harpacticoid copepods were the three dominant groups in the meiofauna, accounting for about

90% of total abundance.  
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Environmental Impact Analysis for Supplemental EP Page 24

The benthic macroinfauna is characterized by small mean individual sizes and low densities,

both of which are a reflection of the meager primary production in Gulf of Mexico surface

waters (Wei, 2006).  Densities decrease exponentially with water depth.  Based on an equation

presented by Wei (2006), macroinfaunal densities in the water depths of the wellsites are

expected to be about 3,400 individuals/m2

, lower than the values in Table 4.

Polychaetes are typically the most abundant macroinfaunal group on the northern Gulf of

Mexico continental slope, followed by amphipods, tanaids, bivalves, and isopods.  Wei (2006)

recognized four depth‐dependent faunal zones (1 through 4), two of which are divided

horizontally.  The lease area is in Zone 2E, which consists of stations on the mid Texas‐Louisiana

Slope ranging in depth from 625 to 1,828 m (2,050 to 5,997 ft).  The five most abundant species

in Zone 2E were the polychaetes Litocorsa antennata, Aricidea suecica, Tharyx marioni, and

Paralacydonia paradoxa and the bivalve Heterodonta sp.

Megafaunal density from nearby stations MT‐3 and MT‐4 was 1,034 and 1,548 individuals/ha,

respectively (Table 4).  Densities of 300 to 2,000 individuals/ha were reported from other

stations in a similar depth range.  Common megafauna included motile groups such as

decapods, ophiuroids, holothurians, and demersal fishes, as well as sessile groups such as

sponges and anemones.

Bacteria are also an important component in terms of biomass and cycling of organic carbon

(Cruz‐Kaegi, 1998).  Bacterial biomass at the depth range of the lease area typically is about

1 to 2 grams of carbon per square meter (g C/m2

) in the top 15 cm of sediments (Rowe and

Kennicutt, 2009).

IPFs potentially affecting benthic communities are effluent discharges (drilling muds and

cuttings) and a large oil spill resulting from a well blowout at the seafloor.  A small fuel spill

would not affect benthic communities because the diesel fuel would float and dissipate on the

sea surface.

Impacts of Effluent Discharges

Drilling muds and cuttings are the only effluents that are likely to affect benthic communities.  

During initial well interval(s) before the marine riser is set, cuttings and seawater‐based “spud

mud” will be released at the seafloor.  Excess cement slurry will also be released at the seafloor

during casing installation for the riserless portion of the drilling operations.  Cement slurry

components typically include cement mix and some of the same chemicals used in water‐based

drilling muds (Boehm et al., 2001).  The main impacts will be burial and smothering of benthic

organisms within several meters to tens of meters around the wellbore.  Soft bottom sediments

disturbed by cuttings, drilling muds, and cement slurry will eventually be recolonized through

larval settlement and migration from adjacent areas.  Because some deep‐sea biota grow and

reproduce slowly, recovery may require several years.

Discharges of treated SBM cuttings from the rig may affect benthic communities, primarily

within several hundred meters of the wellsites.  The fate and effects of SBM cuttings have been

reviewed by Neff et al. (2000), and monitoring studies have been conducted in the Gulf of

Mexico by Continental Shelf Associates, Inc. (2004, 2006).  In general, cuttings with adhering

SBMs tend to clump together and form thick cuttings piles close to the drillsite.  Areas of SBM

cuttings deposition may develop elevated organic carbon concentrations and anoxic conditions

(Continental Shelf Associates, Inc., 2006).  Where SBM cuttings accumulate and concentrations
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 25

exceed approximately 1,000 mg/kg, benthic infaunal communities may be adversely affected

due to both the toxicity of the base fluid and organic enrichment (with resulting anoxia)

(Neff et al., 2000).  Infaunal numbers may increase and diversity may decrease as opportunistic

species that tolerate low oxygen and high H2S predominate (Continental Shelf Associates, Inc.,

2006).  As the base synthetic fluid is decomposed by microbes, the area will gradually return to

pre‐drilling conditions.  Disturbed sediments will be recolonized through larval settlement and

migration from adjacent areas.

The areal extent of impacts from drilling discharges will be small.  Assuming a typical effect

radius of 500 m (1,640 ft), the affected area around each wellsite would represent about 3% of

the seafloor within a lease block.  For the 24 surface locations in this exploration drilling

program, the total impact area would be 314 ha (766 ac).  Soft bottom communities are

ubiquitous along the northern Gulf of Mexico continental slope (Gallaway, 1988; Gallaway et al.,

2003; Rowe and Kennicutt, 2009).  Impacts from drilling discharges during this project will have

no significant impact on soft bottom benthic communities on a regional basis.  This conclusion is

in accord with the findings of the EA for Grid 13 prepared by MMS (2003), which concluded that

development activities in this area would have minimal impacts on the ecological function,

biological productivity, or distribution of soft bottom communities.

Impacts of a Large Oil Spill

The most likely effects of a subsea blowout on benthic communities would be within a few

hundred meters of the wellsites.  The MMS (2007b) estimates that a severe subsurface blowout

could resuspend and disperse sediments within a 300‐m (984‐ft) radius.  While coarse sediments

(sands) would probably settle at a rapid rate within 400 m (1,312 ft) from the blowout site, fine

sediments (silts and clays) could be resuspended for more than 30 days and dispersed over a

much wider area.  Previous studies characterized surface sediments in the vicinity of the site as

about 50% clay and 45% silt (Rowe and Kennicutt, 2009).  

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill

location.  However, during the Macondo spill, subsurface plumes were reported at a water

depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsites and

persisting for more than a month (Camilli et al., 2010).  The subsurface plumes apparently

resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c).  This

observation is supported by Kujawinski et al. (2011) in their report that chemical components of

subsea dispersants used during the Macondo spill persisted for up to two months and were

detected up to 186 miles (300 km) from the wellsite at a water depth of 1,000 to 1,200 m

(3,280 to 3,937 ft).  However, estimated dispersant concentrations in the subsea plume were

below levels known to be toxic to marine life.  While the behavior and impacts of subsurface

plumes are not well known, a subsurface plume could contact the seafloor and affect benthic

communities beyond the 300‐m (984‐ft) radius estimated by MMS (2007a, 2008), depending on

its extent, trajectory, and persistence.  This contact could result in smothering and/or toxicity to

benthic organisms.  The affected area would be recolonized by benthic organisms over a period

of months to years (NRC, 2003).
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Environmental Impact Analysis for Supplemental EP Page 26

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on soft bottom communities are

expected.

C.2.2 High‐Density Deepwater Benthic Communities

As defined by NTL 2009‐G40, high‐density deepwater benthic communities are features or areas

that could support high‐density chemosynthetic communities, or features or areas that could

support high‐density deepwater corals and other associated high‐density hard bottom

communities.  Chemosynthetic communities were discovered in the central Gulf of Mexico in

1984 and have been studied extensively (MacDonald, 2002).  Deepwater coral communities are

also known from numerous locations in the Gulf of Mexico (Brooke and Schroeder, 2007;

CSA International, Inc., 2007).  These communities occur almost exclusively on authigenic

carbonates created by chemosynthetic communities.

The nearest known chemosynthetic community sites are located 44 miles (71 km)

west‐southwest of MC 807 in MC 969.  

The chemosynthetic community assessment included in this Supplemental EP, based on the

shallow hazards report by C&C Technologies, Inc. (2009), did not identify any features that could

support high‐density deepwater benthic communities within 610 m (2,000 ft) of the proposed

drilling mud/cuttings discharge locations.

IPFs potentially affecting high‐density deepwater benthic communities are effluent discharges

(drilling muds and cuttings), and a large oil spill from a well blowout at the seafloor.  A small fuel

spill would not affect benthic communities because the diesel fuel would float and dissipate on

the sea surface.  Because a DP drillship will be used, there will be no anchoring impacts.

Impacts of Effluent Discharges

The chemosynthetic community assessment included in this Supplemental EP, based on the

shallow hazards report by C&C Technologies, Inc. (2009), did not identify any features that could

support high‐density deepwater benthic communities within 610 m (2,000 ft) of the proposed

drilling mud/cuttings discharge locations.  Monitoring programs on the Gulf of Mexico

continental slope have shown that benthic impacts from drilling discharges typically are

concentrated within about 500 m (1,640 ft) of the wellsites, although detectable deposits may

extend beyond this distance (Continental Shelf Associates, Inc., 2004, 2006; Neff et al., 2005).  If

high‐density deepwater communities are associated with the more distant expulsion features

and mud volcanoes identified in the hazards survey, significant impacts on these communities

will be avoided because of the distance from the discharge location.

Impacts of a Large Oil Spill

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill

location.  However, during the Macondo spill, subsurface plumes were reported at a water

depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsites and
Mississippi Canyon Block 807 August 2011

Environmental Impact Analysis for Supplemental EP Page 27

persisting for more than a month (Camilli et al., 2010).  The subsurface plumes apparently

resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c).  This

observation is supported by Kujawinski et al. (2011) in their report that chemical components of

subsea dispersants used during the Macondo spill persisted for up to two months and were

detectable up to 186 miles (300 km) from the wellsite at a water depth of 1,000 to 1,200 m

(3,280 to 3,937 ft).  However, estimated dispersant concentrations in the subsea plume were

below levels known to be toxic to marine life.  While the behavior and impacts of subsurface

plumes are not well known, a subsurface plume could have the potential to contact high‐density

deepwater benthic communities beyond the 300‐m (984‐ft) radius estimated by MMS (2007a,

2008), depending on its extent, trajectory, and persistence.  Potential impacts on sensitive

resources would be an integral part of the decision and approval process for the use of

dispersants.

Potential impacts of oil on high‐density deepwater benthic communities are discussed by

MMS (2007b).  Although chemosynthetic communities live among hydrocarbon seeps, natural

seepage is very constant and occurs at low rates compared to the potential rates of oil release

from a blowout.  In addition, seep organisms also require unrestricted access to oxygenated

water at the same time as exposure to hydrocarbon energy sources (MacDonald, 2002).  Oil

droplets or oiled sediment particles could come into contact with chemosynthetic organisms or

deepwater corals.  As discussed by MMS (2007b), impacts could include loss of habitat,

biodiversity, and live coral coverage; destruction of hard substrate; change in sediment

characteristics; and reduction or loss of one or more commercial and recreational fishery

habitats.  Sublethal effects could be long‐lasting and affect the resilience of coral colonies to

natural disturbances (e.g., elevated water temperature and diseases).

The potential for a spill to affect deepwater corals is indicated by preliminary findings from a

recent (October 2010) survey of deepwater coral habitats near the Macondo spill site

(BOEMRE, 2010).  Government and academic researchers were working at a site 1,400 m

(4,600 ft) deep and approximately 7 miles (11 km) southwest of the Macondo wellhead when

they visually observed dead and dying corals with sloughing tissue and discoloration.  The study

location was about 57 miles (92 km) from the lease area.  Much of the soft coral observed in an

area measuring about 15 to 40 m (50 to 130 ft) was covered by what appeared to be a brown

substance.  Ninety percent of 40 large corals were heavily affected and showed dead and dying

parts and discoloration.  Another site 400 m (1,312 ft) away had a colony of stony corals

similarly affected and partially covered with a similar brown substance.  Until laboratory

analyses are conducted, scientists cannot be certain what caused the impacts.  Sediment and

coral samples were collected with an ROV and brought to the surface for analyses.  Further

testing will also determine if the substance is oil, and if so, whether it is consistent with the

release from the Macondo spill.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on deepwater benthic communities

are expected.
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Environmental Impact Analysis for Supplemental EP Page 28

C.2.3 Designated Topographic Features

The blocks are not within or near a designated topographic feature or a no‐activity zone as

identified in NTL 2009‐G39.  The nearest topographic feature is Sackett Bank, located 36 miles

(58 km) northwest of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to designated topographic features due to the distance from the lease area.  A small

fuel spill would float and dissipate on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf edge.

C.2.4 Pinnacle Trend Area Live Bottoms

The lease area is not covered by the Live Bottom (Pinnacle Trend) Stipulation.  As defined by

NTL 2009‐G39, the nearest pinnacle trend blocks are about 86 miles (138 km) north from the

lease area, along the shelf edge south of Alabama.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to pinnacle trend area live bottoms due to the distance from the lease area.  A small

fuel spill would float on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf edge.

C.2.5 Eastern Gulf Live Bottoms

The lease area is not covered by the Live Bottom (Low‐Relief) Stipulation, which applies to

Eastern Gulf of Mexico Planning Area leases in water depths of 100 m (328 ft) or less.  The

nearest blocks covered by the live bottom stipulation, as defined by NTL 2009‐G39, are about

121 miles (195 km) north‐northeast from the project area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to eastern Gulf live bottom areas due to the distance from the lease area.  A small fuel

spill would float and dissipate on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf.
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Environmental Impact Analysis for Supplemental EP Page 29

C.3 Threatened, Endangered, and Protected Species and Critical Habitat

This section discusses species listed as endangered or threatened under the ESA.  In addition, it

includes all marine mammal species in the region, which are protected under the MMPA.

Endangered or threatened species that may occur in the project area and/or along the northern

Gulf Coast are listed in Table 5.  The table also indicates the location of critical habitat

(if designated in the Gulf of Mexico).  Critical habitat is defined as 1) specific areas within the

geographical area occupied by the species at the time of listing, if they contain physical or

biological features essential to conservation, and those features may require special

management considerations or protection; and 2) specific areas outside the geographical area

occupied by the species if the agency determines that the area itself is essential for

conservation.  The NMFS has jurisdiction over ESA‐listed cetaceans, sea turtles, and fishes in the

Gulf of Mexico.  The USFWS has jurisdiction over ESA‐listed birds and the Florida manatee.

Table 5. Federally‐listed endangered and threatened species in the lease area and along the

northern Gulf Coast.

Species Scientific Name Status

Potential Presence Critical Habitat

Designated in

Gulf of Mexico

Lease

Area Coastal

Marine Mammals

Sperm whale Physeter macrocephalus E X ‐‐  None

Florida manatee Trichechus manatus latirostris E  ‐‐  X Florida

(Peninsular)

Blue whale Balaenoptera musculus E Xa ‐‐  None

Fin whale Balaenoptera physalus E Xa ‐‐  None

Humpback whale Megaptera novaeangliae E Xa ‐‐  None

North Atlantic right whale Eubalaena glacialis E Xa ‐‐  None

Sei whale Balaenoptera borealis E Xa ‐‐  None

Sea Turtles

Loggerhead turtle Caretta caretta T

b X X None

Green turtle Chelonia mydas T, E

c X X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempii E X X None

Birds

Piping Plover Charadrius melodus T  ‐‐  X

Coastal Texas, Louisiana,

Mississippi, Alabama,

and Florida (Panhandle)

Whooping Crane Grus americana E  ‐‐  X

Coastal Texas

(Aransas National

Wildlife Refuge)

Fishes

Gulf sturgeon Acipenser oxyrinchus desotoi T  ‐‐  X

Coastal Louisiana,

Mississippi, Alabama,

and Florida (Panhandle)

Terrestrial Mammals

Beach mouse (Alabama,

Choctawhatchee, Perdido

Key, St. Andrew)

Peromyscus polionotus E  ‐‐  X Alabama and Florida

(Panhandle) beaches

Abbreviations: E = endangered; T = threatened. a

   The blue, fin, humpback, North Atlantic right, and sei whales are rare or extralimital in the Gulf of Mexico and are

unlikely to be present in the lease area. b

   The loggerhead turtle is currently classified as threatened throughout its range.  In March 2010, NMFS and USFWS

proposed to list the Northwest Atlantic Ocean population of loggerhead turtles as endangered (75 FR 12598). c

   The green sea turtle is threatened, except for the Florida breeding population, which is listed as endangered.
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The sperm whale and five species of sea turtles are the only endangered or threatened species

likely to occur at or near the lease area.  No critical habitat has been designated for these

species in the Gulf of Mexico.

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare

or extralimital there (Würsig et al., 2000).  No critical habitat has been designated for these

species in the Gulf of Mexico.

Coastal endangered or threatened species include the Florida manatee, Piping Plover,

Whooping Crane, Gulf sturgeon, and four subspecies of beach mouse.  Critical habitat has been

designated for all of these species as indicated in Table 5 and discussed in individual sections.

Two other coastal species (Bald Eagle and Brown Pelican) discussed by MMS (2007b) are no

longer listed as endangered or threatened; these are discussed under Coastal and Marine Birds.

There are no other endangered animals or plants in the Gulf of Mexico that are reasonably likely

to be affected by either routine or accidental events.  Other species occurring at certain

locations in the Gulf of Mexico such as the smalltooth sawfish (Pristis pectinata), elkhorn coral

(Acropora palmata), staghorn coral (Acropora cervicornis), and Florida salt marsh vole (Microtus

pennsylvanicus dukecampbelli) are remote from the lease area and highly unlikely to be

affected.

C.3.1 Sperm Whale (Endangered)

The only endangered marine mammal likely to be present at or near the project area is the

sperm whale (Physeter macrocephalus).  Resident populations of sperm whales occur within the

Gulf of Mexico.  A species description is presented in a recent lease sale EIS (MMS, 2007b).  Gulf

of Mexico sperm whales are classified as an endangered species and a “strategic stock” (defined

as a stock that may have unsustainable human‐caused impacts) by NMFS (Waring et al., 2009).  

No critical habitat for the sperm whale has been designated in the Gulf of Mexico.

The distribution of sperm whales in the Gulf of Mexico is correlated with mesoscale physical

features such as eddies associated with the Gulf of Mexico Loop Current (Jochens et al., 2008).  

Sperm whale populations in the north‐central Gulf of Mexico are present there throughout the

year (Davis et al., 2000).  Results of a multi‐year tracking study show female sperm whales

typically concentrated along the upper continental slope between the 200‐ and 1,000‐m

(656‐ and 3,280‐ft) depth contours (Jochens et al., 2008).  Male sperm whales were more

variable in their movements and were documented in water depths greater than 3,000 m

(9,843 ft).  Generally, groups of sperm whales sighted in the Gulf of Mexico during the

MMS‐funded Sperm Whale Seismic Study (SWSS) consisted of mixed‐sex groups comprising

adult females and immatures, and groups of bachelor males.  Typical group size for mixed

groups was 10 individuals (Jochens et al., 2008).  SWSS results show that sperm whales transit

through the vicinity of the lease area.  Movements of satellite‐tracked individuals suggest that

this area of the Gulf continental slope is within the home range of the Gulf of Mexico population

(within the 95% utilization distribution) (Jochens et al., 2008).

IPFs potentially affecting sperm whales include drillship presence, noise, and lights; support

vessel and helicopter traffic; and two types of accidents – a small fuel spill and a large oil spill.  

Effluent discharges are likely to have negligible impacts on sperm whales due to rapid
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dispersion, the small area of ocean affected, the intermittent nature of the discharges, and the

mobility of these marine mammals.  Compliance with NTL 2007‐G03 will minimize the potential

for marine debris‐related impacts on sperm whales.

Impacts of Drillship Presence, Noise, and Lights

Noise from routine drilling activities has the potential to disturb sperm whales.  Sperm whales

appear to have good low‐frequency hearing, but the available data do not indicate a consistent

response to anthropogenic noise (Jochens et al., 2008).  Noise associated with drilling is

relatively weak in intensity, and an individual animal’s noise exposure would be transient.  There

are other OCS facilities and activities near the lease area, and the region as a whole has a large

number of similar sources.  Due to the limited scope and short duration of drilling activities, this

project would represent a small temporary contribution to the overall noise regime.

The NMFS (2007) analyzed the potential for impacts of drilling‐related noise on sperm whales in

its Biological Opinion for the Five‐Year Oil and Gas Leasing Program in the Central and Western

Planning Areas of the Gulf of Mexico.  The analysis noted that drilling rigs and drillships show

low sound source levels and concluded that drilling is not expected to produce amplitudes

sufficient to cause hearing or behavioral effects in sperm whales; therefore, these effects are

insignificant (NMFS, 2007).

Although drillship lighting and presence were considered potential factors affecting sperm

whales, NMFS’s 2007 Biological Opinion and recent lease sale EISs (MMS, 2007b, 2008) did not

identify these as IPFs for sperm whales.

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sperm whales, and there is also a risk of vessel

strikes, which are identified as a threat in the recovery plan for this species (NMFS, 2010a).  Data

concerning the frequency of vessel strikes is presented in the lease sale EIS (MMS, 2007b).  To

reduce the potential for vessel strikes, the BOEMRE has issued NTL 2007‐G04, which

recommends protected species identification training and that vessel operators and crews

maintain a vigilant watch for marine mammals and slow down or stop their vessel to avoid

striking protected species, and requires operators to report sightings of any injured or dead

protected species.  When whales are sighted, vessel operators and crews are required to

attempt to maintain a distance of 91 m (300 ft) or greater whenever possible.  Vessel operators

are required to reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large

assemblages of cetaceans are observed near an underway vessel when safety permits.  

Compliance with this NTL will minimize the likelihood of vessel strikes as well as reduce the

chance for disturbing sperm whales.

The NMFS (2007) analyzed the potential for vessel strikes and harassment of sperm whales in its

Biological Opinion for the Five‐Year Oil and Gas Leasing Program in the Central and Western

Planning Areas of the Gulf of Mexico.  With implementation of the mitigation measures in

NTL 2007‐G04, NMFS concluded that the likelihood of collisions between vessels and sperm

whales would be reduced to insignificant levels.  The NMFS concluded that the observed

avoidance of passing vessels by sperm whales is an advantageous response to avoid a potential

threat and is not expected to result in any significant effect on migration, breathing, nursing,

breeding, feeding, or sheltering to individuals, or have any consequences at the level of the

population.  With implementation of the vessel strike avoidance measures requirement to
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maintain a distance of 90 m (295 ft) from sperm whales, the NMFS concluded that the potential

for harassment of sperm whales would be reduced to discountable levels.

Helicopter traffic also has the potential to disturb sperm whales.  Smultea et al. (2008)

documented responses of sperm whales offshore Hawaii to fixed wing aircraft flying at an

altitude of 245 m (800 ft).  A reaction to the initial pass of the aircraft was observed during three

(12%) of 24 sightings.  All three reactions consisted of a hasty dive and occurred at less than

360 m (1,180 ft) lateral distance from the aircraft.  Additional reactions were seen when aircraft

circled certain whales to make further observations.  Based on other studies of cetacean

responses to sound, the authors concluded that the observed reactions to brief overflights by

the aircraft were short‐term and probably of no long‐term biological significance.

While flying offshore in the Gulf of Mexico, helicopters maintain altitudes above 213 m (700 ft)

during transit to and from the working area.  In the event that a whale is seen during transit, the

helicopter will not approach or circle the animals.  Although responses are possible based on the

Smultea et al. (2008) study, the NMFS (2007) concluded that this altitude would minimize the

potential for disturbing sperm whales.  Therefore, no significant impacts are expected.

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals including sperm whales are discussed in recent EISs

(MMS, 2007b, 2008) and by the NMFS (2007) in its Biological Opinion for the Five‐Year Oil and

Gas Leasing Program in the Central and Western Planning Areas of the Gulf of Mexico.  Oil

impacts on marine mammals are discussed by Geraci and St. Aubin (1990).  For this

Supplemental EP there are no unique site‐specific issues with respect to spill impacts on these

animals.

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s

OSRP will mitigate and reduce the potential for impacts on sperm whales.  Supplemental EP

Sections 2j and 9b provide detail on spill response measures.  Given the open ocean location of

the lease area, the duration of a small spill and opportunity for impacts to occur would be very

brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (Marine Mammal Commission [MMC], 2010).  However,

due to the limited areal extent and short duration of water quality impacts from a small fuel

spill, as well as the mobility of sperm whales, no significant impacts would be expected.
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Impacts of a Large Oil Spill

Potential spill impacts on marine mammals including sperm whales are discussed in recent EISs

(MMS, 2007b, 2008) and by the NMFS (2007) in its Biological Opinion for the Five‐Year Oil and

Gas Leasing Program in the Central and Western Planning Areas of the Gulf of Mexico.  Oil

impacts on marine mammals are discussed by Geraci and St. Aubin (1990).  For this

Supplemental EP, there are no unique site‐specific issues with respect to spill impacts on these

animals.

Impacts of oil spills on sperm whales can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants) (MMC, 2010).  Direct physical and physiological effects can include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey; and stress from

the activities and noise of response vessels and aircraft.  Complications of the above may lead to

dysfunction of immune and reproductive systems, physiological stress, declining physical

condition, and death.  Behavioral responses can include displacement of animals from prime

habitat, disruption of social structure, changing prey availability and foraging distribution and/or

patterns, changing reproductive behavior/productivity, and changing movement patterns or

migration (MMC, 2010).

Studies have shown that the cetacean epidermis functions as an effective barrier to noxious

substances found in petroleum (Geraci and St. Aubin, 1985).  Unlike other mammals,

penetration of such substances in cetacean skin is impeded by tight intercellular bridges, the

vitality of the superficial cells, the thickness of the epidermis, and the lack of sweat glands and

hair follicles.  In addition, cetacean skin is free from hair or fur, which in other marine mammals

not found in the Gulf of Mexico (e.g., pinnipeds and otters) tends to collect oil and/or tar.

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb sperm whales and potentially result in vessel strikes, entanglement, or other injury

or stress.  Response vessels would operate in accordance with NTL 2007‐G04 to reduce the

potential for striking or disturbing these animals.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on sperm whales are expected.

C.3.2 Florida Manatee (Endangered)

Most of the manatee population is located in peninsular Florida (USFWS, 2001).  Manatees

regularly migrate farther west of Florida in the warmer months (Wilson, 2003) into Alabama and

Louisiana coastal environs and with some individuals traveling as far as west Texas (Fertl et. al.,

2005).  A species description is presented in a recent lease sale EIS (MMS, 2007b) and in the

recovery plan for this species (USFWS, 2001).

IPFs potentially affecting manatees include support vessel and helicopter traffic and a large oil

spill.  A small fuel spill in the lease area would be unlikely to affect manatees, as the lease area is

approximately 53 miles (85 km) from the nearest shoreline (Louisiana).  As explained in
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Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up.  Compliance with NTL 2007‐G03 will minimize the potential for marine

debris‐related impacts on manatees.

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb manatees, and there is also a risk of vessel

strikes, which are identified as a threat in the recovery plan for this species (USFWS, 2001).  To

reduce the potential for vessel strikes, the BOEMRE has issued NTL 2007‐G04, which

recommends protected species identification training and that vessel operators and crews

maintain a vigilant watch for marine mammals and slow down or stop their vessel to avoid

striking protected species, and requires operators to report sightings of any injured or dead

protected species.  Compliance with this NTL will minimize the likelihood of vessel strikes, and

no significant impacts on manatees are expected.

Helicopter traffic, if present, also has the potential to disturb manatees.  Rathbun (1988)

reported that manatees were disturbed more by helicopters than by fixed‐wing aircraft;

however, the helicopter was flown at a relatively low altitude of 20 to 160 m (66 to 525 ft).  

Helicopters used in support operations maintain a minimum altitude of 213 m (700 ft) while in

transit offshore, 305 m (1,000 ft) over unpopulated areas or across coastlines, and 610 m

(2,000 ft) over populated areas and sensitive habitats such as wildlife refuges and park

properties.  This mitigation measure will minimize the potential for disturbing manatees, and no

significant impacts are expected.

Impacts of a Large Oil Spill

The OSRA results summarized in Table 3 predict that some Texas, Louisiana, and Florida

shorelines could be contacted by a spill within 30 days.  There is no critical habitat designated in

these areas, and the number of manatees potentially present is a small fraction of the

population in peninsular Florida.

In the event that manatees were exposed to oil, effects could include direct impacts from oil

exposure, as well as indirect impacts due to response activities and materials (e.g., vessel traffic,

noise, and dispersants) (MMC, 2010).  Direct physical and physiological effects can include skin

irritation, inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes;

inhalation of toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey

(or contaminated vegetation, in the case of manatees); and stress from the activities and noise

of response vessels and aircraft.  Complications of the above may lead to dysfunction of immune

and reproductive systems, physiological stress, declining physical condition, and death.  

Behavioral responses can include displacement of animals from prime habitat, disruption of

social structure, changing prey availability and foraging distribution and/or patterns, changing

reproductive behavior/productivity, and changing movement patterns or migration

(MMC, 2010).

In the event that a large spill reached coastal waters where manatees were present, the level of

vessel and aircraft activity associated with spill response could disturb manatees and potentially

result in vessel strikes, entanglement, or other injury or stress.  Response vessels would operate

in accordance with NTL 2007‐G04 to reduce the potential for striking or disturbing these

animals, and therefore no significant impacts are expected.
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A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on manatees are expected.

C.3.3 Endangered Mysticete Whales

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare

or extralimital there (Würsig et al., 2000).  No critical habitat has been designated for these

species in the Gulf of Mexico.   

Due to the rare occurrence of these whales in the Gulf of Mexico and the limited scope and

duration of the project, it is highly unlikely that any endangered mysticete would come into

contact with any project activities, either routine operations or accidents.  The NMFS (2007) did

not include any of these mysticete whales as affected species in its Biological Opinion for the

Five‐Year Oil and Gas Leasing Program in the Central and Western Planning Areas of the Gulf of

Mexico.  Potential impacts are analyzed in recent lease sale EISs (MMS, 2007b, 2008), and those

analyses are incorporated by reference.  If any of these whales were present in the area,

potential impacts would be the same as those discussed below in Section C.3.4.

C.3.4 Non‐Endangered Marine Mammals (Protected)

In addition to the seven endangered species that have been cited previously, 22 additional

species of marine mammals that may be found in the Gulf of Mexico (see Supplemental EP

Section 6h).  This includes two mysticete whales, the dwarf and pygmy sperm whales, four

species of beaked whales, and 14 species of delphinids.  The most common non‐endangered

cetaceans in the deepwater environment are odontocetes such as the pantropical spotted

dolphin, spinner dolphin, and clymene dolphin.  All marine mammals are protected species

under the MMPA.  A brief summary is presented below, and additional information on these

groups is presented in a recent lease sale EIS (MMS, 2007b).

Mysticete whales.  Two non‐endangered mysticete whales are known from the Gulf of Mexico:

the Bryde’s whale (Balaenoptera edeni) and minke whale (Balaenoptera acutorostrata).  The

Bryde’s whale has been sighted most frequently along the 100‐m (328‐ft) isobath (Davis and

Fargion, 1996; Davis et al., 2000).  Most sightings have been made in the DeSoto Canyon region

and off western Florida, although there have been some in the west‐central portion of the

northeastern Gulf.  The minke whale (is considered rare in the Gulf of Mexico, with the only

confirmed records coming from strandings (Würsig et al., 2000).  Based on the available data, it

is possible that Bryde’s whales could occur in the lease area.

Dwarf and pygmy sperm whales.  At sea, it is difficult to differentiate dwarf sperm whales

(Kogia sima) from pygmy sperm whales (Kogia breviceps), and sightings are often grouped

together as “Kogia spp.”  Both species have a worldwide distribution in temperate to tropical

waters.  In the Gulf of Mexico, both species occur primarily along the continental shelf edge and

in deeper waters off the continental shelf (Mullin et al., 1991; Mullin, 2007).  Either species

could occur in the lease area.
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Beaked whales.  Four species of beaked whales are known from the Gulf of Mexico.  They are

Blainville’s beaked whale (Mesoplodon densirostris), Cuvier’s beaked whale (Ziphius cavirostris),

Sowerby’s beaked whale (Mesoplodon bidens), and Gervais’ beaked whale (Mesoplodon

europaeus).  Stranding records in the Gulf of Mexico suggest that Gervais’ beaked whale is the

most common and Sowerby’s beaked whale is extralimital.  Due to the difficulties of at‐sea

identification, beaked whales in the Gulf of Mexico are identified either as Cuvier’s beaked

whales or are grouped into an undifferentiated complex (Mesoplodon spp. and Ziphius spp.).  In

the northern Gulf of Mexico, they are broadly distributed in waters greater than 1,000 m

(3,281 ft) over lower slope and abyssal landscapes (Davis et al., 2000).  Any of these species

could occur in the lease area.

Delphinids.  Fourteen species of delphinids are known from the Gulf of Mexico, including

Atlantic spotted dolphin (Stenella frontalis), bottlenose dolphin (Tursiops truncatus), clymene

dolphin (Stenella clymene), false killer whale (Pseudorca crassidens), Fraser’s dolphin

(Lagenodelphis hosei), killer whale (Orcinus orca), melon‐headed whale (Peponocephala electra),

pantropical spotted dolphin (Stenella attenuata), pygmy killer whale (Feresa attenuata),

short‐finned pilot whale (Globicephala macrorhynchus), Risso’s dolphin (Grampus griseus),

rough‐toothed dolphin (Steno bredanensis), spinner dolphin (Stenella longirostris), and striped

dolphin (Stenella coeruleoalba).  The most common non‐endangered cetaceans in the

deepwater environment are the pantropical spotted dolphin, spinner dolphin, and clymene

dolphin.  However, any of these species could occur in the lease area.

IPFs potentially affecting non‐endangered marine mammals include drillship presence, noise,

and lights; support vessel and helicopter traffic; and two types of accidents – a small fuel spill

and a large oil spill.  Effluent discharges are likely to have negligible impacts on marine mammals

due to rapid dispersion, the small area of ocean affected, the intermittent nature of the

discharges, and the mobility of marine mammals.  Compliance with NTL 2007‐G03 will minimize

the potential for marine debris‐related impacts on marine mammals.

Impacts of Drillship Presence, Noise, and Lights

Noise from routine drilling activities has the potential to disturb marine mammals.  Most

odontocetes (toothed whales and dolphins) use sounds that are higher than the low‐frequency

dominant sounds produced by OCS drilling activities (Richardson et al., 1995).  Noise associated

with drilling is relatively weak in intensity, and an individual animal’s noise exposure would be

transient.  There are other OCS facilities and activities near the lease area, and the region as a

whole has a large number of similar sources.  Due to the limited scope and short duration of

drilling activities, this project would represent a small temporary contribution to the overall

noise regime, and any short‐term impacts are not expected to be biologically significant to

marine mammal populations.

Drillship lighting and presence are not identified as IPFs for marine mammals in recent lease sale

EISs (MMS, 2007b, 2008).

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb marine mammals, and there is also a risk of

vessel strikes.  Data concerning the frequency of vessel strikes is presented in the lease sale EIS

(MMS, 2007b).  To reduce the potential for vessel strikes, the BOEMRE has issued

NTL 2007‐G04, which recommends protected species identification training and that vessel
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Environmental Impact Analysis for Supplemental EP Page 37

operators and crews maintain a vigilant watch for marine mammals and slow down or stop their

vessel to avoid striking protected species, and requires operators to report sightings of any

injured or dead protected species.  Vessel operators and crews are required to attempt to

maintain a distance of 91 m (300 ft) or greater when whales are sighted and 45 m (150 ft) when

small cetaceans are sighted.  When cetaceans are sighted while a vessel is underway, vessels

must attempt to remain parallel to the animal’s course and avoid excessive speed or abrupt

changes in direction until the cetacean has left the area.  Vessel operators are required to

reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large assemblages of

cetaceans are observed near an underway vessel, when safety permits.  Compliance with this

NTL will minimize the likelihood of vessel strikes as well as reduce the chance for disturbing

marine mammals, and therefore no significant impacts are expected.

Aircraft traffic also has the potential to disturb marine mammals (Würsig et al., 1998).  However,

while flying offshore, helicopters maintain altitudes above 213 m (700 ft) during transit to and

from the working area.  This altitude will minimize the potential for disturbing marine mammals,

and no significant impacts are expected (MMS, 2007b).

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b, 2008),

and oil impacts on marine mammals in general are discussed by Geraci and St. Aubin (1990).  For

this Supplemental EP, there are no unique site‐specific issues with respect to spill impacts on

these animals.

The probability of a fuel spill will be minimized by Shell’s preventative measures during fuel

transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate

and reduce the potential for impacts on marine mammals.  Supplemental EP Sections 2j and 9b

provide detail on spill response measures.  Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (MMC, 2010).  However, due to the limited areal extent

and short duration of water quality impacts from a small fuel spill, as well as the mobility of

marine mammals, no significant impacts would be expected.

Impacts of a Large Oil Spill

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b, 2008) and

by Geraci and St. Aubin (1990).  For this Supplemental EP, there are no unique site‐specific

issues.
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Environmental Impact Analysis for Supplemental EP Page 38

Impacts of oil spills on marine mammals can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants) (MMC, 2010).  Direct physical and physiological effects can include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey (or

contaminated vegetation, in the case of manatees); and stress from the activities and noise of

response vessels and aircraft.  Complications of the above may lead to dysfunction of immune

and reproductive systems, physiological stress, declining physical condition, and death.  

Behavioral responses can include displacement of animals from prime habitat, disruption of

social structure, changing prey availability and foraging distribution and/or patterns, changing

reproductive behavior/productivity, and changing movement patterns or migration

(MMC, 2010).

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb marine mammals and potentially result in vessel strikes, entanglement, or other

injury or stress.  Response vessels would operate in accordance with NTL 2007‐G04 to reduce

the potential for striking or disturbing these animals, and therefore no significant impacts are

expected.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on marine mammals are expected.

C.3.5 Sea Turtles (Endangered/Threatened)

As listed in Supplemental EP Section 6h, five species of endangered or threatened sea turtles

may be found near the lease area.  Endangered species are the leatherback (Dermochelys

coriacea), Kemp's ridley (Lepidochelys kempii), and hawksbill (Eretmochelys imbricata) turtles.  

The loggerhead turtle (Caretta caretta) is currently a threatened species; however, in

March 2010, NMFS and USFWS proposed to list the Northwest Atlantic Ocean population of

loggerhead turtles as endangered (75 FR 12598).  The green turtle (Chelonia mydas) is listed as

threatened, except for the Florida breeding population, which is listed as endangered.  Species

descriptions are presented in a recent lease sale EIS (MMS, 2007b).

Leatherbacks and loggerheads are the most likely species to be present near the lease area as

adults.  Green, hawksbill, and Kemp’s ridley turtles are typically inner shelf and nearshore

species, unlikely to occur near the lease area as adults.  Hatchlings or juveniles of any of the sea

turtles may be present in deepwater areas, including the lease area, where they may be

associated with Sargassum and other flotsam.

All five sea turtle species in the Gulf of Mexico are migratory and use different marine habitats

according to their life stage.  These habitats include high‐energy beaches for nesting females

and emerging hatchlings and pelagic convergence zones for hatchling and juvenile turtles.  As

adults, green, hawksbill, and loggerhead turtles forage primarily in shallow, benthic habitats.  

Leatherbacks are the most pelagic of the sea turtles, feeding primarily on jellyfish.  
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Sea turtle nesting in the northern Gulf of Mexico can be summarized by species as follows:

• Loggerhead turtles – Loggerheads nest in significant numbers along the Florida Panhandle

and, to a lesser extent, from Texas through Alabama (MMS, 2007b).  The nearest significant

nesting area of loggerhead turtles is found in Louisiana, on beaches within the Breton NWR;

• Green and leatherback turtles – Green and leatherback turtles infrequently nest on Florida

Panhandle beaches (Florida Fish and Wildlife Conservation Commission, 2010);

• Kemp’s ridley turtles – The main Kemp’s ridley nesting site is Rancho Nuevo beach,

Tamaulipas, Mexico (NMFS et al., 2010).  Approximately 200 Kemp’s ridley turtles nested on

Texas beaches in 2009 (Sea Turtle Restoration Project, 2011).  Kemp’s ridley turtles typically

do not nest anywhere near the project area, although there have been occasional reports of

Kemp’s ridleys nesting in Alabama (Share the Beach, 2010); and

• Hawksbill turtles – Hawksbills typically do not nest anywhere near the project area.

IPFs potentially affecting sea turtles include drilling rig and drillship presence, noise, and lights;

support vessel and helicopter traffic; and two types of accidents – a small fuel spill and a large

oil spill.  Effluent discharges are likely to have negligible impacts on sea turtles due to rapid

dispersion, the small area of ocean affected, and the intermittent nature of the discharges.  

Compliance with NTL 2007‐G03 will minimize the potential for marine debris‐related impacts on

sea turtles.

Impacts of Drillship Presence, Noise, and Lights  

Offshore drilling activities produce a broad array of sounds at frequencies and intensities that

may be detected by sea turtles (Geraci and St. Aubin, 1987).  Potential impacts may include

behavioral disruption and temporary or permanent displacement from the area near the sound

source.  Certain sea turtles, especially loggerheads, may be attracted to offshore structures

(Lohoefener et al., 1990) and, thus, may be more susceptible to impacts from sounds produced

during routine operations.  Helicopters and service vessels may also affect sea turtles due to

machinery noise and/or visual disturbances.  The most likely impacts would be short‐term

behavioral changes such as diving and evasive swimming, disruption of activities, or departure

from the area.  Due to the limited scope and short duration of drilling activities, these

short‐term impacts are not expected to be biologically significant to sea turtle populations.

Artificial lighting can disrupt the nocturnal orientation of sea turtle hatchlings (Witherington,

1997; Tuxbury and Salmon, 2005).  However, hatchlings may rely less on light cues when they

are offshore than when they are emerging on the beach (Salmon and Wyneken, 1990).  The

NMFS (2007) concluded that the effects of lighting from offshore structures on sea turtles are

insignificant.

Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sea turtles, and there is also a risk of vessel

strikes.  Data show that vessel traffic is one cause of sea turtle mortality in the Gulf of Mexico

(Lutcavage et al., 1997).  While adult sea turtles are visible at the surface during the day and in

clear weather, they can be difficult to spot from a moving vessel when resting below the water

surface, during nighttime, or during periods of inclement weather.  To reduce the potential for

vessel strikes, the BOEMRE has issued NTL 2007‐G04, which recommends protected species

identification training and that vessel operators and crews maintain a vigilant watch for sea

turtles and slow down or stop their vessel to avoid striking protected species, and requires
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operators to report sightings of any injured or dead protected species.  When sea turtles are

sighted, vessel operators and crews are required to attempt to maintain a distance of 45 m

(150 ft) or greater whenever possible.  Compliance with this NTL will minimize the likelihood of

vessel strikes as well as reduce the chance for disturbing sea turtles (NMFS, 2007).

Helicopter traffic also has the potential to disturb sea turtles.  However, while flying offshore,

helicopters maintain altitudes above 213 m (700 ft) during transit to and from the working area.  

This altitude will minimize the potential for disturbing sea turtles, and no significant impacts are

expected.

Impacts of a Small Fuel Spill

Potential spill impacts on sea turtles are discussed in recent EISs (MMS, 2007b, 2008) and by the

NMFS (2007) in its Biological Opinion for the Five‐Year Oil and Gas Leasing Program in the

Central and Western Planning Areas of the Gulf of Mexico.  For this Supplemental EP, there are

no unique site‐specific issues with respect to spill impacts on these animals.

The probability of a fuel spill will be minimized by Shell’s preventative measures during fuel

transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate

and reduce the potential for impacts on sea turtles.  Supplemental EP Sections 2j and 9b

provide detail on spill response measures.  Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (MMC, 2010).  However, due to the limited areal extent

and short duration of water quality impacts from a small fuel spill, no significant impacts would

be expected.

A small fuel spill in the lease area would be unlikely to affect sea turtle nesting beaches, as the

lease area is 53 miles (85 km) from the nearest shoreline (Louisiana).  As explained in

Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up.

Impacts of a Large Oil Spill

Impacts of oil spills on sea turtles can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants).  Direct physical and physiological effects can include skin irritation, inflammation,

or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of toxic fumes and

smoke (e.g., from in situ burning of oil); ingestion of oil (and dispersants) directly or via
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contaminated food; and stress from the activities and noise of response vessels and aircraft.  

Complications of the above may lead to dysfunction of immune and reproductive systems,

physiological stress, declining physical condition, and death.  Behavioral responses can include

displacement of animals from prime habitat, disruption of social structure, changing food

availability and foraging distribution and/or patterns, changing reproductive

behavior/productivity, and changing movement patterns or migration (MMC, 2010).  In the

unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate and reduce the

potential for these types of impacts on sea turtles.  Supplemental EP Sections 2j and 9b provide

detail on spill response measures.

Studies of oil effects on loggerheads in a controlled setting (Lutcavage et al., 1995) suggest that

sea turtles show no avoidance behavior when they encounter an oil slick, and any sea turtle in

an affected area would be expected to be exposed.  Sea turtles’ diving behaviors also put them

at risk.  Sea turtles rapidly inhale a large volume of air before diving and continually resurface

over time, which may result in repeated exposure to volatile vapors and oiling (NMFS, 2007).

The OSRA results summarized in Table 3 predict that some shorelines that support sea turtle

nesting could be contacted within 10 to 30 days.  The nearest nesting area of loggerhead turtles

is found in St. Bernard Parish, Louisiana, on beaches within the Breton NWR.  This area has a

contact probability of 1% after 30 days.  The modeling also predicts a 1% probability of

contacting Florida Panhandle shorelines that support significant loggerhead sea turtle nesting.

Spilled oil reaching sea turtle nesting beaches could have effects on nesting sea turtles and egg

development (NMFS, 2007).  An oiled beach could affect nest site selection or result in no

nesting at all (e.g., false crawls).  Upon hatching and successfully reaching the water, hatchlings

are subject to the same types of oil spill exposure hazards as adults.  Hatchlings that contact oil

residues while crossing a beach can exhibit a range of effects, from acute toxicity to impaired

movement and normal bodily functions (NMFS, 2007).

Data from the recent Macondo spill provides additional information about potential impacts of a

large oil spill on sea turtles to supplement the analysis presented in the lease sale EIS (MMS,

2007b).  According to NMFS (2010b), approximately 600 dead turtles have been reported since

the Macondo spill.  Species include Kemp’s ridley turtles (481 individuals), loggerhead turtles

(67 individuals), and green turtles (29 individuals).  Oiled turtles include 18 dead individuals and

456 live, oiled animals that were either captured or stranded.  Also, 278 turtle nests were

translocated (271 loggerhead, 4 Kemp’s ridley, and 3 green turtles) and more than

14,000 hatchlings were released.  The strandings and captures ranged from the Louisiana/Texas

border to Cape San Blas in the Florida Panhandle.

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb sea turtles and potentially result in vessel strikes, entanglement, or other injury or

stress.  Response vessels would operate in accordance with NTL 2007‐G04 to reduce the

potential for striking or disturbing these animals, and therefore no significant impacts are

expected.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will
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mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on sea turtles are expected.

C.3.6 Piping Plover (Threatened)

The Piping Plover (Charadrius melodus) is a migratory shorebird that overwinters along the

southeastern U.S. and Gulf of Mexico coasts.  This threatened species is in decline as a result of

hunting, habitat loss and modification, predation, and disease (USFWS, 2003).  Critical

overwintering habitat has been designated, including beaches in Texas, Louisiana, Mississippi,

Alabama, and Florida (Figure 3).  Piping Plovers inhabit coastal sandy beaches and mudflats,

feeding by probing for invertebrates at or just below the surface.  They use beaches adjacent to

foraging areas for roosting and preening (USFWS, 2010a).  A species description is presented in a

recent lease sale EIS (MMS, 2007b).

A large oil spill is the only IPF potentially affecting Piping Plovers.  There are no IPFs associated

with routine project activities that could affect these birds.  A small fuel spill in the lease area

would be unlikely to affect Piping Plovers because a small fuel spill would not be expected to

make landfall or reach coastal waters prior to breaking up (see explanation in Section A.9.2).

Impacts of a Large Oil Spill

The lease area is 58 miles (93 km) from the nearest shoreline inhabited by Piping Plovers.  The

OSRA results summarized in Table 3 predict that Texas, Louisiana, and Florida shorelines

designated as critical habitat for the wintering Piping Plover could be contacted by a spill within

30 days.  Plaquemines Parish, which has the highest probability of contact for the 10‐day and

30‐day intervals, includes Piping Plover critical habitat.

Plovers could physically oil themselves while foraging on oiled shores or secondarily

contaminate themselves through ingestion of oiled intertidal sediments and prey (MMS, 2007b).  

Plovers congregate and feed along tidally exposed banks and shorelines, following the tide out

and foraging at the water’s edge.  It is possible that some deaths of Piping Plovers could occur,

especially if spills occur during winter months when Plovers are most common along the coastal

Gulf or if spills contacted critical habitat.  Impacts could also occur from vehicular traffic on

beaches and other activities associated with spill cleanup.  Shell has extensive resources

available to protect and rehabilitate wildlife in the event of a spill reaching the shoreline, as

detailed in the OSRP.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on Piping Plovers are expected.

C.3.7 Whooping Crane (Endangered)

The Whooping Crane (Grus americana) is an omnivorous wading bird and an endangered

species.  There are three wild populations in North America (Whooping Crane Eastern

Partnership [WCEP], 2010).  One population winters along the Texas coast at Aransas NWR and

summers at Wood Buffalo National Park in Canada.  This population represents the majority of

the world’s population of free‐ranging Whooping Cranes and reached a record population of

270 at Aransas NWR in December 2008 (WCEP, 2010).  A non‐migrating population has been
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re‐introduced in central Florida, and another re‐introduced population summers in Wisconsin

and migrates to the southeastern U.S. for the winter.  Whooping Cranes breed, migrate, winter,

and forage in a variety of habitats, including coastal marshes and estuaries, inland marshes,

lakes, ponds, wet meadows and rivers, and agricultural fields (USFWS, 2007).  About 9,000 ha

(22,240 ac) of salt flats on Aransas NWR and adjacent islands comprise the principal wintering

grounds of the Whooping Crane.  Aransas NWR is designated as critical habitat for the species

(Figure 3).  A species description is presented in a recent lease sale EIS (MMS, 2007b).

A large oil spill is the only IPF potentially affecting Whooping Cranes.  A small fuel spill in the

lease area would also be unlikely to affect Whooping Cranes due to the distance from Aransas

NWR.  As explained in Section A.9.2, a small fuel spill would not be expected to make landfall or

reach coastal waters prior to breaking up.

Impacts of a Large Oil Spill

A large oil spill is unlikely to affect Whooping Cranes because the lease area is approximately

441 miles (710 km) from its critical habitat (Aransas NWR, Texas) and the OSRA modeling

predicts no contact with shorelines of the Aransas NWR within 30 days.

In the event of oil exposure, Whooping Cranes could physically oil themselves while foraging in

oiled areas or secondarily contaminate themselves through ingestion of contaminated shellfish,

frogs, and fishes.  It is possible that some death of Whooping Cranes could occur.  Shell has

extensive resources available to protect and rehabilitate wildlife in the event of a spill reaching

the shoreline, as detailed in the OSRP.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on Whooping Cranes are expected.

C.3.8 Gulf Sturgeon (Threatened)

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is a threatened fish species that inhabits major

rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida

(Barkuloo, 1988; Wakeford, 2001).  An anadromous fish that migrates from the sea upstream

into coastal rivers to spawn in freshwater, it historically ranged from the Mississippi River to

Charlotte Harbor, Florida (Wakeford, 2001).  Today, this range has contracted to encompass

major rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida.  

Populations have been depleted or even extirpated throughout this range by fishing, shoreline

development, dam construction, water quality changes, and other factors (Barkuloo, 1988;

Wakeford, 2001).  These declines prompted the listing of the Gulf sturgeon as a threatened

species in 1991.  The best known populations occur in the Apalachicola and Suwannee Rivers in

Florida (Carr, 1996; Sulak and Clugston, 1998), the Choctawhatchee River in Alabama (Fox et al.,

2000), and the Pearl River in Mississippi/Louisiana (Morrow et al., 1998).  Critical habitat in the

Gulf extends from Lake Borgne, Louisiana (St. Bernard Parish) to Suwannee Sound, Florida

(Levy County) (NMFS, 2010c) (Figure 3).  A species description is presented in a recent lease sale

EIS (MMS, 2007b) and in the recovery plan for this species (USFWS and Gulf States Marine

Fisheries Commission, 1995).
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Figure 3. Location of selected environmental features in relation to the lease area. Shown are Essential Fish Habitat 

coral reefs; Habitat Areas of Particular Concern (HAPC) for northwestern Gulf of Mexico reefs and banks an

bluefin tuna; critical habitat for beach mice, Gulf sturgeon, Piping Plover, and Whooping Crane; and the Ma
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A large oil spill is the only IPF potentially affecting Gulf sturgeon.  There are no IPFs associated

with routine project activities that could affect these fish.  A small fuel spill in the lease area

would be unlikely to affect Gulf sturgeon because a small fuel spill would not be expected to

make landfall or reach coastal waters prior to breaking up (see explanation in Section A.9.2).

Impacts of a Large Oil Spill

Potential spill impacts on Gulf sturgeon are discussed in recent EISs (MMS, 2007b, 2008) and by

the NMFS (2007) in its Biological Opinion for the Five‐Year Oil and Gas Leasing Program in the

Central and Western Planning Areas of the Gulf of Mexico.  For this Supplemental EP, there are

no unique site‐specific issues with respect to this species.

The lease area is about 120 miles (194 km) from the nearest Gulf sturgeon critical habitat.  The

OSRA modeling (Table 3) predicts that a spill in the lease area has a 1% probability of contacting

the coastal areas inhabited by Gulf sturgeon within 30 days.

In the event of oil reaching Gulf sturgeon habitat, the fish could be affected by direct ingestion,

ingestion of oiled prey, or the absorption of dissolved petroleum products through the gills.  

Based on the life history of this species, subadult and adult Gulf sturgeon would be most

vulnerable to an estuarine or marine oil spill, and would be vulnerable only during winter

months (from September 1 through April 30) when this species is foraging in estuarine and

marine habitats (NMFS, 2007).

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Shell has extensive resources available to protect coastal and

estuarine wildlife and habitats in the event of a spill reaching the shoreline, as detailed in the

OSRP.  Supplemental EP Sections 2j and 9b provide detail on spill response measures.  

Therefore, no significant spill impacts on Gulf sturgeon are expected.

C.3.9 Beach Mice (Endangered)

Four subspecies of endangered beach mouse (Peromyscus polionotus) occur on the barrier

islands of Alabama and the Florida Panhandle.  They are the Alabama, Choctawatchee, Perdido

Key, and St. Andrew beach mouse.  Critical habitat has been designated for all four subspecies;

Figure 3 shows the critical habitat combined for all four subspecies.  Species descriptions are

provided in a recent lease sale EIS (MMS, 2007b).

A large oil spill is the only IPF potentially affecting subspecies of beach mouse.  There are no IPFs

associated with routine project activities that could affect these animals due to the distance

from shore and the lack of any onshore support activities near their habitat.  A small fuel spill in

the lease area would not affect any subspecies of beach mouse because a small fuel spill would

not be expected to make landfall or reach coastal waters prior to breaking up (see explanation

in Section A.9.2).

Impacts of a Large Oil Spill

Potential spill impacts on beach mice are discussed in recent EISs (MMS, 2007b, 2008).  For this

Supplemental EP, there are no unique site‐specific issues with respect to these species.
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The lease area is about 159 miles (256 km) from the nearest beach mouse critical habitat.  The

OSRA modeling predicts that a spill in the lease area would not contact beach mouse critical

habitat within 30 days.  (Okaloosa County, Florida, which has a 1% probability after 30 days,

does not include any critical habitat.)

In the event of oil contacting these beaches, beach mice could experience several types of direct

and indirect impacts.  Contact with spilled oil could cause skin and eye irritation and subsequent

infection; matting of fur; irritation of sweat glands, ear tissues, and throat tissues; disruption of

sight and hearing; asphyxiation from inhalation of fumes; and toxicity from ingestion of oil and

contaminated food.  Indirect impacts could include reduction of food supply, destruction of

habitat, and fouling of nests.  Impacts could also occur from vehicular traffic and other activities

associated with spill cleanup.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on beach mice are expected.

C.4 Coastal and Marine Birds

C.4.1 Marine and Pelagic Birds

A variety of seabirds may occur in the pelagic environment of the project areas (Clapp et al.,

1982a,b, 1983; Peake, 1996; Hess and Ribic, 2000).  Seabirds spend much of their lives offshore

over the open ocean, except during breeding season when they nest along the coast.  In

addition, other birds such as waterfowl, marsh birds, and shorebirds may occasionally be

present over open ocean areas.  No endangered or threatened bird species are likely to occur at

the project area due to the distance from shore.  For a discussion of shorebirds and coastal

nesting birds, see Section C.4.2.

Seabirds of the northern Gulf of Mexico were surveyed from ships during the GulfCet II program.  

Hess and Ribic (2000) reported that terns, storm‐petrels, shearwaters, and jaegers were the

most frequently sighted seabirds in the deepwater area.  From these surveys, four ecological

categories of seabirds were documented in the deepwater areas of the Gulf: summer migrants

(e.g., shearwaters, storm petrels, and boobies); summer residents that breed in the Gulf

(e.g., Sooty Tern, Least Tern, Sandwich Tern, and Magnificent Frigatebird); winter residents

(e.g., gannets, gulls, and jaegers); and permanent resident species (e.g., Laughing Gull, Royal

Tern, and Bridled Tern) (Hess and Ribic, 2000).

Common seabird species include Wilson’s Storm‐Petrel (Oceanites oceanicus), Magnificent

Frigatebird (Fregata magnificens), Northern Gannet (Morus bassanus), Masked Booby

(Sula dactylatra), Brown Booby (Sula leucogaster), Cory’s Shearwater (Calonectris diomedea),

Greater Shearwater (Puffinus gravis), and Audubon Shearwater (Puffinus lherminieri).  Seabirds

are distributed Gulf‐wide and are not specifically associated with the lease area.

Relationships with hydrographic features were found for several seabird species, possibly due to

effects of hydrography on nutrient levels and productivity of surface waters where birds forage.  

GulfCet II did not estimate bird densities; however, Powers (1987) indicates that seabird

densities over the open ocean typically are <10 birds/km2

.
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Trans‐Gulf migrant birds including shorebirds, wading birds, and terrestrial birds may also be

present in the lease area.  Migrant birds may use offshore structures and platforms for resting,

feeding, or as temporary shelter from inclement weather (Russell, 2005).  Some birds may be

attracted to offshore structures because of the lights and the fish populations that aggregate

around these structures.

IPFs potentially affecting marine and pelagic birds include drillship presence, noise, and lights;

support vessel and helicopter traffic; and two types of accidents – a small fuel spill and a large

oil spill.  Effluent discharges are likely to have negligible impacts on the birds due to rapid

dispersion, the small area of ocean affected, the intermittent nature of the discharges, and the

mobility of these animals.  Compliance with NTL 2007‐G03 will minimize the potential for marine

debris‐related impacts on birds.

Impacts of Drillship Presence, Noise, and Lights

Birds that frequent platforms may be exposed to contaminants including air pollutants and

routine discharges, but significant impacts are unlikely due to rapid dispersion of effluents and

air pollutants.  Birds migrating over water have been known to strike offshore structures,

resulting in death or injury (Wiese et al., 2001; Russell, 2005).  Mortality of migrant birds at tall

towers and other land‐based structures has been reviewed extensively, and the mechanisms

involved in platform collisions appear to be similar.  In some cases, migrants simply do not see a

part of the platform until it is too late.  In other cases, navigation may be disrupted by noise

(Russell, 2005).  On the other hand, offshore structures are suitable stopover habitats for most

trans‐Gulf migrant species, and most of the migrants that stop over on platforms probably

benefit from their stay, particularly in spring (Russell, 2005).  Due to the limited scope and short

duration of drilling activities in this Supplemental EP, any impacts on populations of either

seabirds or trans‐Gulf migrant birds are not expected to be significant.

A recent study in the North Sea indicated that platform lighting causes circling behavior in

various birds, especially on cloudy nights; apparently the birds’ geomagnetic compass is upset

by the red part of the spectrum from the lights currently in use (Poot et al., 2008).  The numbers

varied greatly, from none at all to some tens of thousands of birds per night per platform, with

an apparent effect radius of up to 3 miles (5 km).  A study in the Gulf of Mexico also noted the

phenomenon, but did not recommend mitigation (Russell, 2005).  Factors to consider in

evaluating this impact in the Gulf of Mexico would include the lower incidence of cloudy and

foggy days in the Gulf of Mexico versus the North Sea.  Due to the limited scope and short

duration of drilling activities proposed in this Supplemental EP, lighting impacts, collisions, or

other adverse effects are unlikely, and no significant impacts are expected.

Impacts of Support Vessel and Helicopter Traffic

Support vessels and helicopters are unlikely to significantly disturb pelagic birds in open,

offshore waters.  It is likely that individual birds would experience, at most, only short‐term

behavioral disruption, and the impact would not be significant.

Impacts of a Small Fuel Spill

Potential spill impacts on marine birds are discussed in recent EISs (MMS, 2007b, 2008).  For this

Supplemental EP, there are no unique site‐specific issues with respect to spill impacts on these

animals.
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The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s

OSRP will mitigate and reduce the potential for impacts on marine and pelagic birds.  

Supplemental EP Sections 2j and 9b provide detail on spill response measures.  Given the open

ocean location of the lease area, the duration of a small spill and opportunity for impacts to

occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Birds exposed to oil on the sea surface could experience direct physical and physiological effects

including skin irritation; chemical burns of skin, eyes, and mucous membranes; and inhalation of

toxic fumes.  Due to the limited areal extent and short duration of water quality impacts from a

small fuel spill, secondary impacts due to ingestion of oil via contaminated prey or reductions in

prey abundance are unlikely.  Due to the low densities of birds in open ocean areas, the small

area affected, and the brief duration of the surface slick, no significant impacts on pelagic birds

would be expected.

Impacts of a Large Oil Spill

Potential spill impacts on marine and pelagic birds are discussed in recent EISs (MMS, 2007b,

2008).  For this Supplemental EP, there are no unique site‐specific issues with respect to spill

impacts on these animals.

Pelagic seabirds could be exposed to oil from a spill at the project area.  Hess and Ribic (2000)

reported that terns, storm‐petrels, shearwaters, and jaegers were the most frequently sighted

seabirds in the deepwater Gulf of Mexico (>200 m).  Powers (1987) indicates that seabird

densities over the open ocean typically are <10 birds/km2

.  The number of pelagic birds that

could be affected in open, offshore waters would depend on the extent and persistence of the

oil slick.

The recent Macondo spill provides relevant information about the species of pelagic birds that

may be affected in the event of a large oil spill.  Birds that have been treated for oiling include

several pelagic species such as the Northern Gannet, Magnificent Frigatebird, and Masked

Booby (International Bird Rescue Research Center, 2010).  The Northern Gannet is among the

species with the largest numbers of birds affected by the spill.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on marine and pelagic birds are

expected.
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C.4.2 Shorebirds and Coastal Nesting Birds

Threatened and endangered bird species (Piping Plover and Whooping Crane) have been

discussed previously in Section C.3.  Various species of non‐endangered birds are also found

along the northern Gulf Coast, including diving birds, shorebirds, marsh birds, wading birds, and

waterfowl.  Gulf Coast marshes and beaches also provide important feeding grounds and

nesting habitats.  Species that breed on beaches, flats, dunes, bars, barrier islands, and similar

habitats include the Sandwich Tern, Wilson’s Plover, Black Skimmer, Forster’s Tern, Gull‐Billed

Tern, Laughing Gull, Least Tern, and Royal Tern (USFWS, 2010b).  Additional information is

presented in recent lease sale EISs (MMS, 2007b, 2008).

The Brown Pelican (Pelecanus occidentalis) was delisted from federal endangered status in 2009

(USFWS, 2010c).  However, this species is listed as a species of greatest conservation need by

the State of Mississippi (Mississippi Department of Wildlife, Fisheries and Parks, 2011) and as a

species of special concern by the State of Florida (Florida Fish and Wildlife Conservation

Commission, 2010). Brown Pelicans inhabit coastal habitats and forage within both coastal

waters and waters of the inner continental shelf.  Aerial and shipboard surveys, including

GulfCet and GulfCet II, indicate that Brown Pelicans do not occur over deep offshore waters

(Fritts and Reynolds, 1981; Peake, 1996; Hess and Ribic, 2000).  Nearly half the southeastern

population of Brown Pelicans lives in the northern Gulf Coast, generally nesting on protected

islands (USFWS, 2010b).

The Bald Eagle (Haliaeetus leucocephalus) was delisted from its threatened status in the lower

48 states on June 28, 2007.  The Bald Eagle is a terrestrial raptor widely distributed across the

southern U.S., including coastal habitats along the Gulf of Mexico.  The Gulf Coast is inhabited by

both wintering migrant and resident Bald Eagles (Johnsgard, 1990; Ehrlich et al., 1992).

IPFs potentially affecting shorebirds and coastal nesting birds include support vessel and

helicopter traffic and a large oil spill.  A small fuel spill in the lease area would be unlikely to

affect shorebirds or coastal nesting birds, as the lease area is 53 miles (85 km) from the nearest

shoreline.  As explained in Section A.9.2, a small fuel spill would not be expected to make

landfall or reach coastal waters prior to breaking up.  Compliance with NTL 2007‐G03 will

minimize the potential for marine debris‐related impacts on shorebirds.

Impacts of Support Vessel and Helicopter Traffic

Support vessels and helicopters will transit coastal areas near Port Fourchon and Boothville,

Louisiana, where shorebirds and coastal nesting birds may be found.  These activities could

periodically disturb individuals or groups of birds within sensitive coastal habitats (e.g., wetlands

that may support feeding, resting, or breeding birds).

Vessel traffic may disturb some foraging and resting birds.  Flushing distances vary between

species and between individuals (Rodgers and Schwikert, 2002).  The disturbances will be

limited to flushing birds away from vessel pathways; known distances are from 20 to 49 m

(65 to 160 ft) for personal watercraft and 23 to 58 m (75 to 190 ft) for an outboard‐powered

boat (Rodgers and Schwikert, 2002).  Flushing distances may be similar or less for the support

vessels to be used for Shell’s project, and some species such as gulls are attracted to boats.  

Support vessels will not approach nesting or breeding areas on the shoreline, so disturbances to

nesting birds, eggs, and chicks is not expected.  Vessel operators will use designated navigation

channels and comply with posted speed and wake restrictions while transiting sensitive inland
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waterways.  Due to the limited scope and short duration of drilling activities, any short‐term

impacts are not expected to be biologically significant to coastal bird populations.

Aircraft traffic can cause some disturbance to birds onshore and offshore.  Responses are highly

dependent on the type of aircraft, the bird species, the activities that animals were previously

engaged in, and previous exposures to overflights (Efroymson et al., 2000).  Helicopters seem to

cause the most intense responses over other human disturbances for some species (Bélanger

and Bédard, 1989).  However, Federal Aviation Administration Advisory Circular No. 91‐36D

recommends that pilots maintain a minimum altitude of 610 m (2,000 ft) when flying over

noise‐sensitive areas such as wildlife refuges, parks, and areas with wilderness characteristics.  

This is greater than the distance (slant range) at which aircraft overflights have been reported to

cause behavioral effects on most species of birds studied (Efroymson et al., 2000).  With these

guidelines in effect, it is likely that individual birds would experience, at most, only short‐term

behavioral disruption.

Impacts of Large Oil Spill

The OSRA results summarized in Table 3 predict that shorelines of Texas, Louisiana, and Florida

that include habitat for shorebirds and coastal nesting birds could be affected within 30 days.

Data from the recent Macondo spill provides additional information about the species of coastal

birds that may be affected in the event that a large oil spill reached coastal habitats; this

information supplements the analysis presented in the lease sale EIS (MMS, 2007b).  According

to USFWS (2010d) and based on the latest reports, about 5,000 dead birds had been collected

since the spill began, and about 1,900 of the dead animals were visibly oiled.  In addition, over

2,000 oiled birds had been collected alive and about 1,200 released (NMFS, 2010b).  According

to the International Bird Rescue Research Center (2010), bird species that were treated for oiling

following the Macondo spill include the following:

• Brown Pelican

• White Pelican

• Masked Booby

• Magnificent Frigatebird

• Laughing Gull

• Herring Gull

• Northern Gannet

• Black Crowned Night Heron

• Tri‐colored Heron

• Green Heron

• Cattle Egret

• Snowy Egret

• Reddish Egret

• Least Bittern

• Common Tern

• Royal Tern

• Caspian Tern

• Sandwich Tern

• Forsters Tern

• Black Tern

• Gull‐billed Tern

• Least Tern

• Black Skimmer

• Black Oystercatcher

• White Ibis

• Roseate Spoonbill

• Willet

• Sanderling

• Dunlin

• Semipalmated Sandpiper

• Killdeer

• King Rail

• Clapper Rail

• Virginia Rail
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According to the USFWS (2010d), species with the largest numbers of dead, oiled birds were

Laughing Gull, Northern Gannet, Brown Pelican, Royal Tern, Black Skimmer, Least Tern,

unidentified Gull, and unidentified Tern.  There are no reports of Bald Eagle oiling.

Coastal birds can be exposed to oil as they float on the water’s surface, dive during foraging, or

wade in oiled coastal waters.  Oiled birds can lose the ability to fly, dive for food, or float on the

water, which could lead to drowning (USFWS, 2010e).  Oil interferes with the water repellency

of feathers and can cause hypothermia in the right conditions.  As birds groom themselves, they

can ingest and inhale the oil on their bodies.  Scavengers such as Bald Eagles and gulls can be

exposed to oil by feeding on carcasses of contaminated fish and wildlife.  While ingestion can kill

animals immediately, more often it results in lung, liver, and kidney damage, which can lead to

death.  Bird eggs may be damaged if an oiled adult sits on the nest.

As noted above, the Brown Pelican was recently removed from the endangered species list.  

Over 300 dead Brown Pelicans have been collected in the Gulf following the Macondo spill,

(USFWS, 2010d).  These data indicate that Brown Pelicans may be particularly at risk of oiling in

the event of a large spill reaching coastal waters.  Issues for Brown Pelicans include direct

contact with oil, disturbance by cleanup activities, and long‐term habitat contamination.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on shorebirds and coastal nesting

birds are expected.

C.5 Fisheries Resources

C.5.1 Pelagic Communities and Ichthyoplankton

Biggs and Ressler (2000) reviewed the biology of pelagic communities in the deepwater

environment of the northern Gulf of Mexico.  The biological oceanography of the region is

dominated by the influence of the Loop Current, whose surface waters are among the most

oligotrophic in the world’s oceans.  Superimposed on this low‐productivity condition are

productive “hot spots” associated with entrainment of nutrient‐rich Mississippi River water and

mesoscale oceanographic features.  Anticyclonic and cyclonic hydrographic features play an

important role in determining biogeographic patterns and controlling primary productivity in the

northern Gulf of Mexico (Biggs and Ressler, 2000).

Most fishes inhabiting shelf or oceanic waters of the Gulf of Mexico have planktonic eggs and

larvae (Ditty, 1986; Ditty et al., 1988; Richards et al., 1989, 1993).  Pelagic eggs and larvae

become part of the planktonic community for various lengths of time (10 to 100 days,

depending on the species) (MMS, 2007b).

IPFs potentially affecting pelagic communities and ichthyoplankton include drillship presence,

noise, and lights; effluent discharges; water intakes; and two types of accidents – a small fuel

spill and a large oil spill.
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Impacts of Drillship Presence, Noise, and Lights

The drillship, as floating structures in the deepwater environment, will act as fish‐attracting

devices (FADs).  In oceanic waters, the FAD effect would be most pronounced for epipelagic

fishes such as tunas, dolphin, billfishes, and jacks, which are commonly attracted to fixed and

drifting surface structures (Holland et al., 1990; Higashi, 1994; Relini et al., 1994).  This FAD

effect could possibly enhance the feeding of epipelagic predators by attracting and

concentrating smaller fish species.  Because the drillship is a temporary structure, impacts on

fish populations, whether beneficial or adverse, are considered minor.

Impacts of Effluent Discharges

Treated sanitary and domestic wastes may have a slight effect on the pelagic environment in the

immediate vicinity of these discharges.  These wastes may have elevated levels of nutrients,

organic matter, and chlorine, but should be diluted rapidly to undetectable levels within tens to

hundreds of meters from the source.  Minimal impacts on water quality, plankton, and nekton

are anticipated.

Deck drainage may have a slight effect on the pelagic environment in the immediate vicinity of

these discharges.  Deck drainage from contaminated areas will be passed through an oil and

water separator prior to release, and discharges will be monitored for visible sheen.  The

discharges may have slightly elevated levels of hydrocarbons but should be diluted rapidly to

undetectable levels within tens to hundreds of meters from the source.  Minimal impacts on

water quality, plankton, and nekton are anticipated.

Other discharges in accordance with the NPDES permit, such as desalination unit brine and

uncontaminated cooling water, fire water, and ballast water, are expected to be diluted rapidly

and have little or no impact on water column biota.

Impacts of Water Intakes

Seawater will be drawn from the ocean for once‐through, non‐contact cooling of machinery

on the drilling rig or drillship.  The estimated intake and discharge of cooling water is

100,000 BPD (4.19 MGD).  Section 316(b) of the Clean Water Act requires NPDES permits to

ensure that the location, design, construction, and capacity of cooling water intake structures

reflect the best technology available to minimize adverse environmental impact from

impingement and entrainment of aquatic organisms.  The Noble Bully I meets the applicability

criteria for a “new” facility as defined by the current general NPDES permit No. GMG 290000

and therefore is subject to the cooling water intake permit requirements.  All affected intakes

will be in compliance with the design, monitoring, and recordkeeping requirements of the

NPDES permit.

The intake of seawater for cooling water will entrain plankton.  The low intake velocity should

allow most strong‐swimming juvenile fishes and smaller adults to escape entrainment or

impingement.  However, drifting plankton would not be able to escape entrainment with the

exception of a few fast‐swimming larvae of certain taxonomic groups.  Those organisms

entrained may be stressed or killed, primarily through changes in water temperature during the

route from cooling intake structure to discharge structure, and mechanical damage (turbulence

in pumps and condensers).  Due to the limited scope and short duration of drilling activities, any
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short‐term impacts of entrainment are not expected to be biologically significant to plankton or

ichthyoplankton populations.

Impacts of a Small Fuel Spill

Potential spill impacts on fisheries resources are discussed in recent EISs (MMS, 2007b, 2008).  

For this Supplemental EP, there are no unique site‐specific issues with respect to spill impacts.

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s

OSRP will mitigate and reduce the potential for impacts on pelagic communities, including

ichthyoplankton.  Supplemental EP Sections 2j and 9b provide detail on spill response

measures.  Given the open ocean location of the lease area, the duration of a small spill and

opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

A small fuel spill could have localized impacts on phytoplankton, zooplankton, ichthyoplankton,

and nekton.  Due to the limited areal extent and short duration of water quality impacts, small

fuel spill would be unlikely to produce detectable impacts on pelagic communities.

Impacts of a Large Oil Spill

A large oil spill could affect water column biota including phytoplankton, zooplankton,

ichthyoplankton, and nekton.  A large spill that persisted for weeks or months would be more

likely to affect these communities.  While adult and juvenile fishes may actively avoid a large

spill, planktonic eggs and larvae would be unable to avoid contact.  Eggs and larvae of fishes are

especially vulnerable to oiling because they inhabit the upper layers of the water column, and

they will die if exposed to certain toxic fractions of spilled oil.  Impacts would be potentially

greater if local scale currents retained planktonic larval assemblages (and the floating oil slick)

within the same water mass.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on pelagic communities and

ichthyoplankton are expected.

C.5.2 Essential Fish Habitat

Essential Fish Habitat (EFH) is defined as those waters and substrate necessary to fish for

spawning, breeding, feeding, and growth to maturity.  Under the Magnuson‐Stevens Fishery

Conservation and Management Act, as amended, Federal agencies are required to consult on
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activities that may adversely affect EFH designated in Fishery Management Plans developed by

the regional Fishery Management Councils.

The Gulf of Mexico Fishery Management Council (GMFMC) has prepared Fishery Management

Plans for corals and coral reefs, shrimps, stone crab, spiny lobster, reef fishes, coastal migratory

pelagic fishes, and red drum.  In 2005, the EFH for these managed species was redefined in

Generic Amendment No. 3 to the various Fishery Management Plans (GMFMC, 2005).  The EFH

for most of these GMFMC‐managed species is on the continental shelf in waters shallower than

183 m (600 ft).  The shelf edge is the outer boundary for coastal migratory pelagic fishes, reef

fishes, and shrimps.  EFH for corals and coral reefs includes some shelf‐edge topographic

features on the Texas‐Louisiana OCS, the nearest of which is Sackett Bank, located 36 miles

(58 km) north‐northwest of the lease area.

Highly migratory pelagic fishes, which occur as transients in the lease area, are the only

remaining group for which EFH has been identified in the deepwater Gulf of Mexico.  Species in

this group, including tunas, swordfishes, billfishes, and sharks, are managed by NMFS.  Highly

migratory species with EFH at or near the lease area include the following (NMFS, 2009):

• Atlantic bigeye tuna (juveniles)  

• Atlantic bluefin tuna (spawn, eggs,

larvae, adults)

• Atlantic skipjack tuna (spawn,

adults)

• Atlantic yellowfin tuna (spawn,

juveniles, adults)

• Atlantic swordfish (larvae, juveniles,

adults)

• Blue marlin (juveniles, adults)

• White marlin (juveniles, adults)

• Sailfish (juveniles)

• Longbill spearfish (juveniles, adults)

• Oceanic whitetip shark (all)

• Silky shark (all)

• Whale shark (all)

• Longfin mako shark (all)

• Bigeye thresher shark (all)

Recent research indicates the central and western Gulf of Mexico may be important spawning

habitat for Atlantic bluefin tuna, and NMFS (2009) has designated a Habitat Area of Particular

Concern (HAPC) for this species.  The HAPC covers much of the deepwater Gulf of Mexico,

including the lease area (Figure 3).  The areal extent of the HAPC is approximately 300,000 km2

(15,000 mi2).  The prevailing assumption is that Atlantic bluefin tuna follow an annual cycle of

foraging in June through March off the eastern United States and Canadian coasts, followed by

migration to the Gulf of Mexico to spawn in April, May, and June (NMFS, 2009).  

Other HAPCs have been identified in the Gulf of Mexico by the GMFMC (2005).  These include

the Florida Middle Grounds, Madison‐Swanson Marine Reserve, Tortugas North and South

Ecological Reserves, Pulley Ridge, and several individual reefs and banks of the northwestern

Gulf of Mexico (Figure 3).  The nearest of these is Jakkula Bank, located 143 miles (231 km) west

of the lease area.  

Routine IPFs potentially affecting EFH and fisheries resources include drillship presence, noise,

and lights; effluent discharges; water intakes; and two types of accidents – a small fuel spill and

a large oil spill.  

Impacts of Drillship Presence, Noise, and Lights

The drillship, as a floating structure in the deepwater environment, will act as an FAD.  In

oceanic waters, the FAD effect would be most pronounced for epipelagic fishes such as tunas,
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dolphin, billfishes, and jacks, which are commonly attracted to fixed and drifting surface

structures (Holland et al., 1990; Higashi, 1994; Relini et al., 1994).  This FAD effect would

possibly enhance feeding of epipelagic predators by attracting and concentrating smaller fish

species.  Because the drillship is a temporary structure, any impacts on EFH for highly migratory

pelagic fishes are considered minor.

Impacts of Effluent Discharges

Other effluent discharges affecting EFH by diminishing ambient water quality include drilling

muds and cuttings, treated sanitary and domestic wastes, deck drainage, and miscellaneous

discharges such as desalination unit brine and uncontaminated cooling water, fire water, and

ballast water.  Impacts on water quality have been discussed previously.  No significant impacts

on EFH for highly migratory pelagic fishes are expected from these discharges.

Impacts of Water Intakes

As noted previously, cooling water intake will cause entrainment and impingement of plankton,

including fish eggs and larvae (ichthyoplankton).  Due to the limited scope and short duration of

drilling activities, any short‐term impacts on EFH for highly migratory pelagic fishes are not

expected to be biologically significant.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s

OSRP will mitigate and reduce the potential for impacts on EFH.  Supplemental EP Sections 2j

and 9b provide detail on spill response measures.  Given the open ocean location of the lease

area, the duration of a small spill and opportunity for impacts to occur would be very brief.

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008).  For this

Supplemental EP, there are no unique site‐specific issues with respect to spill impacts.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

A small fuel spill could have localized impacts on EFH for highly migratory pelagic fishes,

including tunas, swordfishes, billfishes, and sharks.  These species occur as transients in the

lease area.  A spill would also produce short‐term impacts on water quality in the HAPC for

spawning Atlantic bluefin tuna, which covers much of the deepwater Gulf of Mexico.  The areal

extent of the affected area would represent a negligible portion of the HAPC, which covers

297,312 km2 (114,793 mi2

) of the Gulf of Mexico.

A small fuel spill would not affect EFH for corals and coral reefs, the nearest of these EFH areas

being Sackett Bank, located 36 miles (58 km) north‐northwest of the lease area.  A small fuel

spill would float and dissipate on the sea surface and would not contact these features.
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Impacts of a Large Oil Spill

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008).  For this

Supplemental EP, there are no unique site‐specific issues with respect to EFH.

An oil spill in offshore waters would temporarily increase hydrocarbon concentrations on the

water surface and potentially the subsurface as well.  Given the extent of EFH designations in

the Gulf of Mexico (GMFMC, 2005; NMFS, 2009), some impact on EFH would be unavoidable.

A large spill could affect the EFH for many managed species including shrimps, stone crab, spiny

lobster, reef fishes, coastal migratory pelagic fishes, and red drum.  It would result in adverse

impacts on water quality and water column biota including phytoplankton, zooplankton, and

nekton.  In coastal waters, sediments could be contaminated and result in persistent

degradation of the seafloor habitat for managed demersal fish and shellfish species.

The lease area is within the HAPC for spawning Atlantic bluefin tuna (NMFS, 2009).  A large spill

could temporarily degrade the HAPC due to increased hydrocarbon concentrations in the water

column, with the potential for lethal or sublethal impacts on spawning tuna.  Potential impacts

would depend in part on the timing of a spill, as this species migrates to the Gulf of Mexico to

spawn in April, May, and June (NMFS, 2009).

The pinnacle trend area, located 86 miles (138 km) north from the lease area, is designated as

EFH under the corals and coral reefs management plan.  An accidental spill would be unlikely to

affect this area.  A surface slick would not reach these features.  Although there are reports of

subsurface plumes resulting from the use of subsea dispersants during the Macondo spill, the

distance and difference in water depth are factors that would make an impact unlikely.  

Near‐bottom currents in the region are expected to flow along the isobaths (Nowlin et al., 2001)

and typically would not carry a plume up onto the continental shelf edge.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on EFH are expected.

C.6 Archaeological Resources

C.6.1 Shipwreck Sites

MC 807 is on the list of leases with a high potential for historic shipwrecks.  An Archaeological

Assessment was conducted by C&C Technologies, Inc. (2009) for Blocks 762, 763, 806, and 807.  

There were 5,637 unidentified sonar contacts located within these blocks.  These sonar contacts

were characteristic of modern debris primarily associated with industrial dumping or lease

development activities.  No shipwrecks were found within MC 807.  

Because there are no historic shipwreck sites in the lease area, there are no routine IPFs that are

likely to affect these resources.  Impacts of a large oil spill are the only IPFs considered.  A small

fuel spill would not affect shipwrecks in adjoining blocks because the oil would float and

dissipate on the sea surface.
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Impacts of a Large Oil Spill

The MMS (2007b) estimated that a severe subsurface blowout could resuspend and disperse

sediments within a 300‐m (984‐ft) radius.  Because there are no historic shipwrecks in the lease

area, this impact would not be relevant.

A spill entering shallow coastal waters could conceivably contaminate an undiscovered

shipwreck site.  The OSRA modeling summarized in Table 3 predicts that Texas, Louisiana, and

Florida shorelines could be contacted by a spill within 30 days.  Also as noted by MMS (2007b),

should an oil spill contact a coastal historic site, such as a fort or a lighthouse, the major impact

would be a temporary, reversible visual impact from oil contact and contamination of the site

and its environment.

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

archaeological sites beyond the immediate vicinity of the wellhead (i.e., due to physical impacts

of a blowout) because the oil would rise quickly to the sea surface directly over the spill location.  

However, during the Macondo spill, subsurface plumes were reported at a water depth of about

1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsite and persisting for more

than a month (Camilli et al., 2010).  The subsurface plumes apparently resulted from the use of

dispersants at the wellhead (Joint Analysis Group, 2010c).  While the behavior and impacts of

subsurface plumes are not well known, a subsurface plume could have the potential to contact

shipwreck sites beyond the 300‐m (984‐ft) radius estimated by MMS (2007a, 2008), depending

on its extent, trajectory, and persistence.  If oil from a subsea spill should come into contact with

wooden shipwrecks on the seafloor it could adversely affect their condition or preservation.  

Should there be any indication that potential shipwreck sites could be affected, in accordance

with NTL 2005‐G07 Shell will immediately halt operations, take steps to ensure that the site is

not disturbed in any way, and contact the Regional Supervisor, Leasing and Environment, within

48 hours of its discovery.  Shell would cease all operations within 305 m (1,000 ft) of the site

until the Regional Director provides instructions on steps to take to assess the site’s potential

historic significance and protect it.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on historic shipwrecks are expected.

C.6.2 Prehistoric Archaeological Sites

With water depths ranging from 1,149 to 1,155 m (3,769 to 3,789 ft), the wellsites are well

beyond the 60‐m (197‐ft) depth contour used by the BOEMRE as the seaward extent for

prehistoric archaeological site potential in the Gulf of Mexico.  Because prehistoric

archaeological sites are not found in the lease area, the only relevant IPF is a large oil spill that

would reach coastal waters within the 60‐m (197‐ft) depth contour.

Impacts of a Large Oil Spill

Because prehistoric archaeological sites are not found in the lease area, they would not be

affected by the physical effects of a subsea blowout.  The MMS (2007b) estimates that a severe

subsurface blowout could resuspend and disperse sediments within a 300‐m (984‐ft) radius.
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Along the northern Gulf Coast, prehistoric sites occur frequently along the barrier islands and

mainland coast and along the margins of bays and bayous (MMS, 2007b).  The OSRA modeling

summarized in Table 3 predicts that Texas, Louisiana, and Florida shorelines could be contacted

by a spill within 30 days.  A spill reaching a prehistoric site along these shorelines could coat

fragile artifacts or site features and compromise the potential for radiocarbon dating organic

materials in a site (although other dating methods are available and it is possible to

decontaminate an oiled sample for radiocarbon dating).  Coastal prehistoric sites could also be

damaged by spill cleanup operations (e.g., by destroying fragile artifacts and disturbing the

provenance of artifacts and site features).

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on archaeological resources are

expected.

C.7 Coastal Habitats and Protected Areas

Coastal habitats in the northeastern Gulf of Mexico that may be affected by oil and gas activities

are described in recent EISs (MMS, 2007b, 2008) and in a literature review by Collard and Way

(1997).  Sensitive coastal habitats are also tabulated in the OSRP.  Coastal habitats inshore of the

project area include barrier beaches and dunes, wetlands, and submerged seagrass beds.  

Generally, most of the northeastern Gulf is fringed by barrier beaches, with wetlands and/or

submerged seagrass beds occurring in sheltered areas behind the barrier islands and in

estuaries.

Due to the distance from shore, there are no IPFs associated with routine offshore activities that

are likely to affect beaches and dunes, wetlands, seagrass beds, coastal wildlife refuges,

wilderness areas, or any other managed or protected coastal area.  The support bases at

Port Fourchon and Boothville, Louisiana are not located in wildlife refuges or a wilderness areas.  

Potential impacts of support vessel traffic are briefly addressed below.

A small fuel spill in the lease area would be unlikely to affect coastal habitats, as the lease area is

53 miles (85 km) from the nearest shoreline (Louisiana).  As explained in Section A.9.2, a small

fuel spill would not be expected to make landfall or reach coastal waters prior to breaking up.

Impacts of Support Vessel Traffic

For OCS activities in general, support operations, including crew boats and supply boats, may

have a minor incremental impact on coastal habitats.  Over time with a large number of vessel

trips, vessel wakes can erode shorelines along inlets, channels, and harbors.  Support

operations, including crew boats and supply boats as detailed in Supplemental EP Section 14,

may have a minor incremental impact on coastal habitats or protected areas.  Impacts will be

minimized by following the speed and wake restrictions in harbors and channels.

Impacts of a Large Oil Spill

Potential spill impacts on coastal habitats are discussed in recent EISs (MMS, 2007b, 2008).  

Coastal habitats inshore of the project area include barrier beaches and dunes, wetlands, and
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submerged seagrass beds.  For this Supplemental EP, there are no unique site‐specific issues

with respect to coastal habitats.

The OSRA results summarized in Table 3 predict that shorelines of Texas, Louisiana, and Florida

could be affected within 30 days.  Plaquemines Parish, Louisiana has the highest probability of

contact for the 10‐day and 30‐day intervals (4% and 8%, respectively).  Two other Louisiana

parishes (Terrebonne and Lafourche) may be contacted within 10 days.  After 30 days,

11 counties or parishes may be contacted from Galveston, Texas, to Okaloosa County in the

Florida Panhandle.

The shorelines within the geographic range predicted by the OSRA modeling include extensive

barrier beaches and wetlands, with submerged seagrass beds occurring in sheltered areas

behind the barrier islands and in estuaries.  NWRs and other protected areas along the coast are

discussed in the lease sale EIS (MMS, 2007b) and Shell’s OSRP.  Coastal wildlife refuges,

wilderness areas, and State and national parks within the geographic range of the potential

shoreline contacts after 30 days include the following:

• Galveston Island State Park

• Brazoria NWR

• Apffel Park

• Seawolf Park

• Old Fort Travis Park

• Atkinson Island Wildlife Management

Area (WMA)

• Ft. Anahuac Park

• Anahuac NWR

• McFaddin NWR

• Sea Rim State Park

• J.D. Murphree WMA

• Texas Point NWR

• Sabine NWR

• Cameron Prairie NWR

• LaCassine NWR

• Little Pecan Island Preserve

• Peveto Woods  Sanctuary

• Lower Neches WMA

• Rockefeller State Wildlife Refuge and

Game Preserve

• Paul J. Rainey WMA

• Marsh Island WMA

• Cypremort Point State Park

• Atchafalaya Delta WMA

• Mandalay NWR

• Isles Dernieres Barrier Islands Refuge

• Pointe Au Chien WMA

• Wisner WMA

• Grand Isle State Park

• Salvador WMA

• Jean Lafitte National Historical Park

and Preserve

• Delta NWR

• Pass a Loutre WMA

• Breton NWR

• St. Bernard State Park

• Biloxi WMA

• Bayou Sauvage NWR

• Gulf Islands National Seashore

The OSRA results in Table 3 include only shoreline segments with contact probabilities greater

than 0.5% within 30 days; other coastal areas could be affected at lower contact probabilities

within 30 days, or from a spill persisting for more than 30 days.  Additional NWRs and managed

wildlife areas occur along the Gulf Coast.  These areas include habitats such as barrier beach and

dune systems, wetlands, and submerged seagrass beds that support diverse wildlife, including

endangered or threatened species.
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The level of impacts from oil spills on coastal habitats depends on many factors, including the oil

characteristics, the geographic location of the landfall, and the weather and oceanographic

conditions at the time (MMS, 2007b).  Oil that makes it to beaches may be either liquid

weathered oil, an oil‐and‐water mousse, or tarballs (MMS, 2007b).  Oil is generally deposited on

beaches in lines defined by wave action at the time of landfall.  Oil that remains on the beach

will thicken as its volatile components are lost.  Thickened oil may form tarballs or aggregations

that incorporate sand, shell, and other materials into its mass.  Tar may be buried to varying

depths under the sand.  On warm days, both exposed and buried tarballs may liquefy and ooze.  

Oozing may also serve to expand the size of a mass as it incorporates beach materials.  Oil on

beaches may be cleaned up manually, mechanically, or both.  Some oil can remain on the beach

at varying depths and may persist for several years as it slowly biodegrades and volatilizes.

Wetlands are highly sensitive to oiling.  The MMS (2007b) predicted that for every 50 bbl of oil

contacting wetlands, approximately 2.7 ha (6.7 ac) of wetland vegetation will experience

dieback.  Thirty percent of these damaged wetlands are assumed to recover within 4 years, and

85% within 10 years.  About 15% of the contacted wetlands are expected to be converted

permanently to open‐water habitat.  The critical concentration of oil is that concentration above

which impacts to wetlands will be long‐term and recovery will take longer than two growing

seasons, and which causes plant mortality and some permanent wetland loss.  Critical

concentrations of various oils are expected to vary broadly for wetland types and wetland plant

species.  Louisiana wetlands are assumed to be more sensitive to oil contact than elsewhere in

the Gulf because of high cumulative stress (MMS, 2007b).  In addition to the direct impacts of

oil, cleanup activities in marshes may accelerate rates of erosion and retard recovery rates,

which have been reported to require from years to decades following a spill (MMS, 2007b).

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on coastal habitats are expected.

C.8 Socioeconomic and Other Resources

C.8.1 Recreational and Commercial Fishing

The main commercial fishing activity in deep waters of the northern Gulf of Mexico is pelagic

longlining for tunas, swordfishes, and other billfishes (Continental Shelf Associates, Inc., 2002).  

Pelagic longlining has occurred historically in the project area, primarily during spring and

summer.  In August 2000, the Federal government closed two areas in the northeastern Gulf of

Mexico to longline fishing (65 Federal Register 47214, August 1, 2000).  The lease area is outside

of the closure areas.

Longline gear consists of monofilament line deployed from a moving vessel and generally

allowed to drift for 4 to 5 hours (Continental Shelf Associates, Inc., 2002).  As the mainline is put

out, baited leaders and buoys are clipped in place at regular intervals.  It takes 8 to 10 hours to

deploy a longline and about the same time to retrieve it.  Longlines are often set near

oceanographic features such as fronts or downwellings, with the aid of sophisticated on‐board

temperature sensors, depth finders, and positioning equipment.  Vessels are 10 to 30 m long,
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and their trips last from about 1 to 3 weeks.  The main homeports for longlining vessels are in

Louisiana (Dulac and Venice) and Florida (Destin, Madeira Beach, and Panama City).

It is unlikely that any commercial fishing activity other than longlining occurs at or near the

project area.  Benthic species targeted by commercial fishers occur on the upper continental

slope, well inshore of the project area.  Royal red shrimp are caught by trawlers in water depths

of about 250 to 550 m (820 to 1,804 ft).  Tilefish are caught by bottom longlining in water

depths from about 165 to 450 m (540 to 1,476 ft) (Continental Shelf Associates, Inc., 2002). The

proposed project is in 923 m (3,028 ft) of water.  No conflict with commercial fishing activity is

expected to occur.

Most recreational fishing activity in the region occurs in water depths less than 200 m (656 ft)

(Continental Shelf Associates, Inc., 1997, 2002).  In deeper water, the main attraction to

recreational fishers would be petroleum platforms offshore Texas and Louisiana.  The Mars

tension leg platform (TLP) and nearby Ursa TLP are known sites of recreational fishing in the

region (Continental Shelf Associates, Inc., 2002).

The only routine IPF potentially affecting fisheries is drillship presence (including noise and

lights).  Two potential accidents are also addressed below – a small fuel spill and a large oil spill.

Impacts of Drillship Presence

There is a slight possibility of pelagic longlines becoming entangled in the drillship.  For example,

in January 1999, a portion of a pelagic longline snagged on the acoustic Doppler current profiler

of a drillship working in the Gulf of Mexico (Continental Shelf Associates, Inc., 2002).  The line

was removed without incident.  Generally, longline fishers use radar and are aware of offshore

structures and ships when placing their sets.  Therefore, little or no impact on pelagic longlining

is expected.

No adverse impacts on fishing activities are anticipated.  Other factors such as effluent

discharges are likely to have negligible impacts on commercial or recreational fisheries due to

rapid dispersion, the small area of ocean affected, and the intermittent nature of the discharges.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s

OSRP will mitigate and reduce the potential for impacts.  Supplemental EP Sections 2j and 9b

provide detail on spill response measures.  Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

Pelagic longlining activities in the lease area could be interrupted in the event of a small fuel

spill.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.  Fishing activities could be

interrupted due to the activities of response vessels operating in the lease area.  A small fuel

spill would not affect coastal water quality because the spill would not be expected to make

landfall or reach coastal waters prior to breaking up (see Section A.9.2).
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Impacts of a Large Oil Spill

Potential spill impacts on fishing activities are discussed in recent EISs (MMS, 2007b, 2008).  For

this Supplemental EP, there are no unique site‐specific issues with respect to this activity.

Pelagic longlining activities in the lease area and other fishing activities in the northern Gulf of

Mexico could be interrupted in the event of a large oil spill.  A spill may or may not result in

fishery closures, depending on the duration of the spill, the oceanographic and meteorological

conditions at the time, and the effectiveness of spill response measures.  The recent Macondo

spill provides information about the maximum potential extent of fishery closures in the event

of a large oil spill in the Gulf of Mexico (NMFS, 2010d).  At its peak on July 12, 2010, closures

encompassed 217,821 km2 (84,101 mi2

), or 34.8% of the U.S. Exclusive Economic Zone (EEZ) in

the Gulf of Mexico.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on fishing activities are expected.

C.8.2 Public Health and Safety

There are no IPFs associated with routine operations that are expected to affect public health

and safety.  Impacts of a small fuel spill and a large oil spill are addressed below.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s

OSRP will mitigate and reduce the potential for impacts.  Supplemental EP Sections 2j and 9b

provide detail on spill response measures.   

A small fuel spill would not have any impacts on public health and safety because it would affect

only a small area of the open ocean 53 miles (85 km) from the nearest shoreline (Louisiana) and

nearly all of the diesel fuel would evaporate or disperse naturally within 24 hours.  Response

crews would be equipped with appropriate safety equipment to avoid injury and health effects.  

A small fuel spill would not be expected to make landfall or reach coastal waters prior to

breaking up (see Section A.9.2).

Impacts of a Large Oil Spill  

In the event of a large spill from a blowout, the main safety and health concerns are those of the

offshore personnel involved in the incident and those responding to the spill.  The proposed

activities will be covered by the OSRP, and, in addition, the drillship will maintain a Shipboard Oil

Pollution Emergency Plan as required under MARPOL 73/78.

Depending on the spill rate and duration, the physical/chemical characteristics of the oil, the

meteorological and oceanographic conditions at the time, and the effectiveness of spill response

measures, the public could be exposed to oil on the water and along the shoreline, including

skin contact or breathing VOCs.  Crude oil is a highly flammable material, and any smoke or
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vapors from a crude oil fire can cause irritation, and in large quantities may pose a health

hazard.

Data from the recent Macondo spill provide relevant information about the types of health

issues that may occur in the event of a large oil spill (Centers for Disease Control and Prevention,

2010a).  Wildlife cleaning  and rehabilitation workers have reported concerns including scrapes

and cuts, itchy or red skin or rash, and symptoms of headache or feeling faint, dizzy, or fatigued.  

Hand, shoulder, or back pain was also reported by some wildlife cleaning workers.  Personnel

working on offshore vessels or providing direct oversight to offshore vessels, including

USCG personnel, civilian contractors, and other responders who were exposed to oil and

dispersants, had 7 to 12 times higher prevalence of upper respiratory symptoms and cough than

those not exposed (Centers for Disease Control and Prevention, 2010b).  Another potential

occupational hazard for spill response workers in general was heat stress from work in a hot and

humid environment.  Initial symptoms from cleanup workers who sought medical care in

Louisiana were typical of acute exposure to hydrocarbons or H2S such as headaches, dizziness,

nausea, vomiting, cough, respiratory distress, and chest pain (Solomon and Janssen, 2010).  

Health effects reported from previous oil spills, such as the Exxon Valdez in 1989, were primarily

acute injuries consisting of headaches, throat irritation, and sore or itchy eyes, but respiratory

problems and dermatitis along with chronic airway disease have also been reported (Solomon

and Janssen, 2010).

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on public health and safety are

expected.

C.8.3 Employment and Infrastructure

There are no IPFs associated with routine operations that are expected to affect employment

and infrastructure.  The project involves drilling with support from existing shorebase facilities in

Louisiana.  No new or expanded facilities will be constructed, and no new employees are

expected to move permanently into the area.  The project will have a negligible impact on

socioeconomic conditions such as local employment, existing offshore and coastal infrastructure

(including major sources of supplies, services, energy, and water), and minority and lower

income groups.  Impacts of a small fuel spill and a large oil spill are addressed below.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s

OSRP will mitigate and reduce the potential for impacts.  Supplemental EP Sections 2j and 9b

provide detail on spill response measures.  Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill that is dissipated within a few days would have little or no economic impact, as

the spill response would use existing facilities, resources, and personnel.
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Impacts of a Large Oil Spill  

Potential socioeconomic impacts of an oil spill are discussed in recent EISs (MMS, 2007b, 2008).  

For this Supplemental EP, there are no unique site‐specific issues with respect to employment

and coastal infrastructure.  A large spill could cause economic impacts in several ways: it could

result in extensive fishery closures that put fishermen out of work; it could result in temporary

employment as part of the response effort; it could result in adverse publicity that affects

employment in coastal recreation and tourism industries; and it could result in another

suspension of OCS drilling activities, including service and support operations that are an

important part of local economies.

The lease area is 53 miles (85 km) from the nearest shoreline (Louisiana).  Based on OSRA

modeling as summarized in Table 3, Texas, Louisiana, and Florida coastal areas are the most

likely to be contacted by a spill.   

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on employment and infrastructure

are expected.

C.8.4 Recreation and Tourism

There are no known recreational uses of the lease area.  Recreational resources and tourism in

coastal areas would not be affected by any routine activities due to the distance from shore.  

Compliance with NTL 2007‐G03 will minimize the chance of trash or debris being lost overboard

from the drilling rig or drillship and subsequently washing up on beaches.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s

OSRP will mitigate and reduce the potential for impacts.  Supplemental EP Sections 2j and 9b

provide detail on spill response measures.  Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in the lease area would be unlikely to affect recreation and tourism.  There are

no known recreational or tourism activities occurring in the lease area, and as explained in

Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up.

Impacts of a Large Oil Spill  

Potential impacts of an oil spill on recreation and tourism are discussed in recent EISs

(MMS, 2007b, 2008).  For this Supplemental EP, there are no unique site‐specific issues with

respect to these impacts.

Impacts on recreation and tourism would vary depending on the duration of the spill and its fate

including the effectiveness of response measures.  A large spill that reached coastal waters and

shorelines could adversely affect recreation and tourism by contaminating beaches and
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wetlands, resulting in negative publicity that encourages people to stay away.  Based on OSRA

modeling as summarized in Table 3, Plaquemines Parish, Louisiana, is the area most likely to be

contacted by a spill.  However, shorelines from Galveston, Texas, to the Florida Panhandle could

be contacted.  These areas include popular beaches and recreational sites along the coast.

In addition to the analysis presented by MMS (2007b, 2008), recent and ongoing studies have

explored the economic impacts of the Macondo spill including tourism and “brand” damage

(IEM, 2010; Oxford Economics, 2010).  The U.S. Travel Association has estimated the economic

impact of the Macondo spill on tourism across the Gulf Coast over a 3‐year period at

$22.7 billion (Oxford Economics, 2010).  There are ongoing efforts to accelerate recovery by

informing public perceptions; creating travel incentives; and providing access to capital, low

interest loans, and tax incentives for affected businesses (U.S. Travel Association, 2010).

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on recreation and tourism are

expected.

C.8.5 Land Use

Land use along the northern Gulf Coast is discussed in recent lease sale EISs (MMS, 2007b,

2008).  There are no routine IPFs potentially affecting land use.  The project will use existing

onshore support facilities in Louisiana.  The land use at the existing shorebase sites is industrial.  

The project will not involve any new construction or changes to existing land use and, therefore,

will not have any impacts.  Levels of boat and helicopter traffic, as well as demand for goods and

services including scarce coastal resources, will represent a small fraction of the level of activity

occurring at the shorebases.

A large oil spill is the only relevant IPF.  A small fuel spill would not have any impacts on land

use, as the response would be staged out of existing shorebases and facilities.

Impacts of a Large Oil Spill  

The initial response for a large oil spill would be staged out of existing facilities, with no effect on

land use.  A large spill could have limited temporary impacts on land use along the coast if

additional staging areas were needed.  For example, during the Macondo spill, temporary

staging areas were established in Louisiana, Mississippi, Alabama, and Florida for spill response

and cleanup efforts.  In the event of a large spill in the lease area, similar temporary staging

areas could be needed.  These areas would eventually return to their original use as the

response is demobilized.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on land use are expected.
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C.8.6 Other Marine Uses

The lease area is not located within any USCG‐designated fairway or shipping lane.  MC 807 is

not in a designated Military Warning Area.  Shell will comply with BOEMRE requirements and

lease stipulations to avoid impacts on uses of the area by military vessels and aircraft.

There are existing subsea facilities on the seafloor in the lease area.  All pre‐existing seafloor

hardware, flowlines, and umbilicals have a 152‐m (500‐ft) avoidance buffer around each item to

prevent impacts.  

A discontinued industrial waste dump area that was active in the 1970s is located to the

southwest of the lease area (C&C Technologies, Inc., 2009).  Shell has prepared a

BOEMRE‐approved plan for “Waste Barrel Avoidance and Release Response in the Mississippi

Canyon Area” that applies to operations that could cause a disturbance of a seafloor barrel.  

Shell’s over‐arching policy is to avoid barrel contact.  The plan specifies a safe stand‐off distance

from the waste barrels of 10 m (33 ft) and requires that potential impact locations be surveyed

with an ROV to maximize barrel avoidance.  In the unlikely case that contact is suspected or has

been made with any wastes from a barrel, the plan specifies actions to be taken for the topside

safety of personnel handling the equipment.  The plan also outlines barrel impact reporting

procedures.

There are no IPFs from routine project activities that are likely to affect shipping or other marine

uses.  Physical disturbance to existing wells, flowlines, and umbilicals will be prevented by the

152‐m (500‐ft) avoidance zone established around these features.  A large oil spill is the only

relevant accident IPF.  A small fuel spill would not have any impacts on other marine uses, as the

spill and response activities would be mainly within the lease area and the duration would be

brief.

Impacts of a Large Oil Spill  

An accidental spill would be unlikely to significantly affect shipping or other marine uses.  The

block is not located within any USCG‐designated fairway or shipping lane.  In the event of a large

spill requiring numerous response vessels, coordination would be required to manage the vessel

traffic for safe operations.  Shell will comply with BOEMRE requirements and lease stipulations

to avoid impacts on uses of the area by military vessels and aircraft.

In the event of a large spill requiring numerous vessels in the area, coordination would be

required to ensure that no anchoring or seafloor‐disturbing activities occur near the existing

pipelines and flowlines.  In addition, the procedures detailed in Shell’s Waste Barrel Avoidance

and Release Response Plan would be adhered to during response to any spill in the area.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an

event will be minimized by Shell’s well control and blowout prevention measures as detailed in

Supplemental EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the impacts.  Supplemental EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on other marine uses are expected.
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C.9 Cumulative Impacts

For purposes of NEPA, cumulative impact is defined as “the impact on the environment which

results from the incremental impact of the action when added to other past, present, and

reasonably foreseeable future actions regardless of what agency (Federal or non‐Federal) or

person undertakes such other actions” (40 CFR 1508.7).  Any single activity or action may have a

negligible impact(s) by itself, but when combined with impacts from other activities in the same

area and/or time period, substantial impacts may result.

Prior Studies.  MC 807 was acquired in Lease Sale #98 on May 22, 1985.  Prior to the lease sale,

MMS prepared a multisale EIS in which it analyzed the environmental impact of activities that

might occur in the multi‐lease‐sale area.  The MMS also recently analyzed the cumulative

impacts of OCS development activities similar to those planned in this Supplemental EP in

several documents.  The level and types of activities planned in Shell's Supplemental EP are

within the range of activities described and evaluated in the Final EIS for Gulf of Mexico OCS Oil

and Gas Lease Sales 2007‐2012: Western Planning Area Sales 204, 207, 210, 215, and 218, and

Central Planning Area Sales 205, 206, 208, 213, 216, and 222 (MMS, 2007b), as updated by a

2008 Final Supplemental EIS for Gulf of Mexico OCS Oil and Gas Lease Sales 2009‐2012: Central

Planning Area Sales 208, 213, 216, and 222 and Western Planning Area Sales 210, 215, and 218

(MMS, 2008).  Past, present, and reasonably foreseeable activities were identified in the

cumulative effects scenario.  These documents are incorporated by reference.

Description of Activities Reasonably Expected to Occur in the Vicinity of Project Area.  During

part of the time frame of the batch set and drilling activities included in this Supplemental EP,

Shell will be conducting ongoing development and production activities in MC 809 associated

with the Ursa Princess field development, in MC 762 associated with the West Boreas field

development, and in MC 807 associated with the Mars A field development.  Shell currently is

unaware of any other projects that are planned to occur in lease blocks adjacent to those

included in this Supplemental EP.

Cumulative Impacts of Activities in the Supplemental EP.  The MMS (2007b) multi‐lease‐sale EIS

included a lengthy discussion of cumulative impacts, which analyzed the environmental and

socioeconomic impacts from the incremental impact of the 11 proposed lease sales, in addition

to all activities (including non‐OCS activities) projected to occur from past, proposed, and future

lease sales during the 40‐year period of 2007 to 2046 (MMS, 2007b, page 4‐301).  The EIS

considered exploration, delineation, and development wells; platform installation; service‐vessel

trips; and oil spills.  The EIS examined the potential cumulative effects on each specific resource

for the entire Gulf of Mexico.

The level and type of activity proposed in Shell’s Supplemental EP are within the range of

activities described and evaluated in the recent multi‐lease‐sale EISs.  This EIA incorporates and

builds on these analyses by examining the potential impacts on physical, biological, and

socioeconomic resources from the work planned in this Supplemental EP, in conjunction with

the other reasonably foreseeable activities expected to occur in the Gulf of Mexico, as well as

the known impacts from the Macondo spill in MC 252.  While another large oil spill could have

significant impacts, the numerous new safety measures implemented by the BOEMRE and

further mitigation and safety measures proposed by Shell in its Supplemental EP result in a

drilling program that reduces the likelihood of another large spill and improves the effectiveness

of any response in the extremely unlikely event that another large spill occurs.  Thus, for all
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impacts, the incremental contribution of Shell’s proposed actions to the cumulative impacts

analysis in these prior analyses is not significant.

C.9.1 Cumulative Impacts to Physical/Chemical Resources

The work planned in this Supplemental EP is limited in geographic scope and duration, and the

impacts on the physical/chemical environment will be correspondingly limited.  

Air Quality.  Emissions from pollutants into the atmosphere from activities are not projected to

have significant effects on onshore air quality because of the prevailing atmospheric conditions,

emission rates and heights, and resulting pollutant concentrations.  As the BOEMRE found in the

multi‐lease‐sale EISs, the incremental contribution of activities similar to Shell’s proposed

activities to the cumulative impacts is not significant and will not cause or contribute to a

violation of any national ambient air quality standard (MMS, 2007b, 2008).  In addition, the

cumulative contribution to visibility impairment is also very small (MMS, 2007b, 2008).  Since

the BOEMRE completed the multi‐lease‐sale EISs, USEPA has adopted a new short‐term NAAQS

for NO2.  The standard has not yet been implemented in the Gulf Coast states, but given the

levels of expected emissions and the distance of the project from shore, emissions from Shell's

Supplemental EP are not likely to contribute to violations of any NAAQS onshore.

Climate Change.  CO2 and CH4 emissions from the project would constitute a small incremental

contribution to greenhouse gas emissions from all OCS activities.  According to the

Programmatic EIS (MMS, 2007a), estimated CO2 emissions from all OCS activities in the

2007‐2012 leasing program are about 0.08% to 0.016% of the global CO2 emissions from fossil

fuel combustion.  Greenhouse gas emissions may contribute to climate change, with important

effects on temperature, rainfall, frequency of severe weather, ocean acidification, and sea level

rise (Intergovernmental Panel on Climate Change, 2007).  In the Gulf of Mexico, sea level rise is

an important issue due to the ongoing losses in coastal wetlands, particularly in coastal

Louisiana.  Greenhouse gas emissions from the Supplemental EP represent a negligible

contribution to the total greenhouse gas emissions from reasonably foreseeable activities in the

Gulf of Mexico area and would not significantly alter any of the climate change impacts

evaluated in the lease sale EIS or Programmatic EIS.  Globally, Shell is working to reduce

greenhouse gas emissions by increasing the efficiency of its operations, establishing a

substantial capability in CO2 capture and storage, and continuing to research and develop

technologies that increase efficiency and reduce emissions in hydrocarbon production.  Shell’s

direct greenhouse gas emissions in 2009 were 11% lower than in 2008 and approximately

35% below the 1990 level (Shell, 2009).  Shell’s ongoing efforts to reduce greenhouse gas

emissions should offset any incremental contribution from the Supplemental EP.

Water Quality.  Shell’s project will have some minor water quality impacts due to the

NPDES‐permitted discharge of drilling muds and cuttings, treated sanitary and domestic wastes,

excess cement, non‐contact cooling water, deck drainage, desalination unit brine,

uncontaminated fire water, and ballast water.  These effects are expected to be minor (localized

to the area within a few hundred meters of the discharge point), and temporary (lasting only

hours longer than the disturbance or discharge).  Any cumulative effects to water quality are

expected to be negligible.
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New Information.  The only new, potentially significant information available since preparation

of the multi‐lease‐sale EISs arises from the Macondo spill.  The Macondo spill caused short‐term,

localized air quality impacts, e.g., from evaporation of volatile hydrocarbons and in situ burning

of floating oil.  Monitoring by the USEPA (2010) has found levels of ozone and particulates

ranging from “good” to “unhealthy for sensitive groups” on USEPA’s Air Quality Index; these are

at levels well below those that would cause short‐term health problems.  The air monitoring

conducted to date has not found any pollutants at levels expected to cause long‐term harm

(USEPA, 2010).  Satellite imagery indicates that the surface slick from the Macondo spill did

reach the lease area (ESRI, 2010).  However, based on the information currently available, there

is no reason to expect any change in air quality conditions or cumulative impacts from those

predicted in the multi‐lease‐sale EISs.  

The Macondo spill also resulted in water quality impacts.  In addition to the oil slick on the sea

surface, plumes of submerged oil droplets were produced when subsea dispersants were

applied at the wellhead (Camilli et al., 2010; Hazen et al., 2010; Joint Analysis Group, 2010a,b,c).  

Satellite imagery indicates that the surface slick from the Macondo spill did reach the lease area

(ESRI, 2010), and it is also possible that subsurface plumes could have affected water quality in

or near the lease area.  However, OSAT (2010) reported that, after August 2010, waters and

sediments in the deepwater Gulf of Mexico beyond 1.8 miles (3 km) from the Macondo wellsite

were below USEPA acute and chronic benchmarks for PAHs and were not hypoxic.  These

observations indicate that baseline environmental conditions in the lease area are unlikely to

have been significantly altered by the spill.  Prior to the incident, water quality in deep, offshore

waters was expected to be good, with low levels of contaminants (Kennicutt, 2000).  Based on

the information currently available, there is no reason to expect any change in water quality

conditions or cumulative impacts from those predicted in the multi‐lease‐sale EISs.

C.9.2 Cumulative Impacts to Biological Resources

The work planned in this Supplemental EP is limited in geographic scope and duration, and the

impacts on biological resources will be correspondingly limited.  

Seafloor Habitats and Biota.  Effects on seafloor habitats and biota from discharges of drilling

mud and cuttings are expected to be minor and limited to a small area.  There are no areas that

may support high‐density deepwater benthic communities within 610 m (2,000 ft) of the

wellsites, as required by NTL 2009‐G40.  Soft bottom communities are ubiquitous along the

northern Gulf of Mexico continental slope, and the extent of benthic impacts during this project

is insignificant regionally.  As noted in the multi‐lease‐sale EISs, the incremental contributions of

activities similar to Shell’s proposed activities to the cumulative impacts is not significant

(MMS, 2007b, page 4‐325).

Threatened, Endangered, and Protected Species.  Threatened and endangered species

reasonably likely to occur in the lease area include the sperm whale and five species of sea

turtles.  Potential impact sources include drillship presence including noise and lights; marine

debris; and support vessel and aircraft traffic.  Potential effects for these species would be

limited and temporary, and would be reduced by Shell’s compliance with all BOEMRE‐required

mitigation measures including NTLs 2007‐G03 and 2007‐G04.  No significant cumulative impacts

are expected.
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Coastal and Marine Birds.  Some birds may be attracted to offshore structures because of the

lights and the fish populations that aggregate around these structures.  Birds that frequent

platforms may be exposed to contaminants including air pollutants and routine discharges, but

significant impacts are unlikely due to rapid dispersion.  Shell’s compliance with NTL 2007‐G03

will minimize the likelihood of debris‐related impacts on birds.  Support vessel and helicopter

traffic may disturb some foraging and resting birds; however, it is likely that individual birds

would experience, at most, only short‐term behavioral disruption.  Due to the limited scope and

short duration of drilling activities, collisions or other adverse effects are unlikely, and no

significant cumulative impacts are expected.

Fisheries Resources.  Drillships and drilling rigs are known to be FADs, such that some species of

epipelagic fishes may be attracted to the rig and potentially attract predators.  These short‐term

effects are expected to be small given the isolated nature of the drilling rig or drillship and

would not be considered a significant impact on pelagic communities, fishery resources, or EFH.  

When the drilling rig or drillship is on‐site, these effects would be temporarily additive to those

associated with other exploration and production structures in the area, but would occur at low

levels such that the cumulative effect would be negligible.

Coastal Habitats.  Due to the distance from shore, routine activities are not expected to have

any impacts on beaches and dunes, wetlands, seagrass beds, coastal wildlife refuges, wilderness

areas, or any other managed or protected coastal area.  The support bases at Port Fourchon and

Boothville, Louisiana are not in wildlife refuges or a wilderness areas.  Support operations,

including crew boats and supply boats, may have a minor incremental impact on coastal

habitats.  Over time with a large number of vessel trips, vessel wakes can erode shorelines along

inlets, channels, and harbors.  Impacts will be minimized by following the speed and wake

restrictions in harbors and channels.

New Information.  The only new, potentially significant information available since preparation

of the multi‐lease‐sale EISs arises from the Macondo spill.  The spill has resulted in impacts on

biological resources, including visibly oiled and/or dead birds, marine mammals, and sea turtles,

as well as oiling of coastal habitats from approximately the Texas/Louisiana border to the Florida

Panhandle.  Another large spill could result in significant cumulative impacts to these resources.  

However, for all the reasons discussed in the Supplemental EP, Shell’s NTL 2010‐N06 response,

the OSRP, and herein, the likelihood of a catastrophic well control event resulting in significant

amounts of oil in the water is extremely remote.  Therefore, Shell’s proposed activities are not

expected to result in any cumulative impacts to biological resources affected by the Macondo

spill, nor should they have any impact on the previously conducted cumulative impact analyses.

Regarding deepwater benthic communities, the multi‐lease‐sale EISs (MMS, 2007a, 2008)

concluded that oil spills would be unlikely to affect benthic communities beyond the immediate

vicinity of the wellhead (i.e., due to physical impacts of a blowout) because the oil would rise

quickly to the sea surface directly over the spill location.  However, during the Macondo spill,

subsurface plumes were reported at a water depth of about 1,100 m (3,600 ft), extending at

least 22 miles (35 km) from the wellsites and persisting for more than a month (Camilli et al.,

2010).  The subsurface plumes apparently resulted from the use of dispersants at the wellhead

(Joint Analysis Group, 2010c).  This observation is supported by Kujawinski et al. (2011) in their

report that chemical components of subsea dispersants used during the Macondo spill persisted

for up to two months and were detected up to 186 miles (300 km) from the wellsite at a water

depth of 1,000 to 1,200 m (3,280 to 3,937 ft).  However, estimated dispersant concentrations in
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the subsea plume were below levels known to be toxic to marine life.  While the behavior and

impacts of subsurface plumes are not well known, a subsurface plume could contact the

seafloor and affect benthic communities beyond the 300‐m (984‐ft) radius estimated by MMS

(2007a, 2008), depending on its extent, trajectory, and persistence.  This contact could result in

smothering and/or toxicity to benthic organisms.  The affected area would be recolonized by

benthic organisms over a period of months to years (NRC, 2003).

C.9.3 Cumulative Impacts to Socioeconomic Resources

The work planned in this Supplemental EP is limited in geographic scope and duration, and the

impacts on socioeconomic resources will be correspondingly limited.

Archaeological Resources.  MC 807 is on the list of leases with a high potential for historic

shipwrecks.  An archaeological assessment by C&C Technologies, Inc. (2009) indicated that none

of the sonar contacts in the lease area were interpreted as historic shipwrecks.  Also, the lease

area is well beyond the 60‐m (197‐ft) depth contour used by the BOEMRE as the seaward extent

for prehistoric archaeological site potential in the Gulf of Mexico.  Therefore, Shell’s operations

will have no cumulative impacts on historic shipwrecks or prehistoric archaeological resources.

Socioeconomic Resources.  The multi‐lease‐sale EISs analyzed the cumulative impacts of oil and

gas exploration and development in the lease area, in combination with other impact‐producing

activities, on commercial fishing, recreational fishing, recreational resources, historical and

archaeological resources, land use and coastal infrastructure, demographics, and environmental

justice (MMS, 2007b, pages 4‐359 to 4‐378).  The BOEMRE also analyzed the economic impact of

oil and gas activities on the Gulf States, finding only minor impacts in most of Texas, Mississippi,

Alabama, and Florida, more significant impact in parts of Texas, and substantial impact on

Louisiana.

Shell’s proposed activities will have negligible cumulative impacts on socioeconomic resources.  

There are no IPFs associated with routine operations that are expected to affect public health

and safety, employment and infrastructure, recreation and tourism, land use, or other marine

uses.  Due to the distance from shore, it is unlikely that any recreational fishing activity is

occurring in the project area, and it is unlikely that any commercial fishing activity other than

longlining occurs at or near the project area.  The project will have negligible impacts on fishing

activities.

New Information.  The only new, potentially significant information available since preparation

of the multi‐lease‐sale EISs arises from the Macondo spill.  The spill has resulted in impacts on

commercial and recreational fishing, recreation and tourism, employment, and public health

and safety.  The Macondo spill resulted in extensive fishery closures in the Gulf of Mexico,

peaking at 34.8% of the EEZ in the Gulf of Mexico (NMFS, 2010d).  The U.S. Travel Association

has estimated the economic impact of the Macondo spill on tourism across the Gulf Coast over a

3‐year period at $22.7 billion (Oxford Economics, 2010).  Reported health impacts (e.g., among

spill response and wildlife rehabilitation workers) ranged from cuts and scrapes, to upper

respiratory symptoms and heat stress, to acute exposure to hydrocarbons or H2S (Centers for

Disease Control and Prevention, 2010a,b; Solomon and Janssen, 2010).  Most of these impacts

were temporary in nature, although health exposure of clean‐up workers could have

longer‐lasting impacts.
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However, for all the reasons discussed in the Supplemental EP, Shell’s NTL 2010‐N06 response,

the OSRP, and herein, the likelihood of a catastrophic well control event resulting in significant

amounts of oil in the water is extremely remote.  Therefore, Shell’s proposed activities are not

expected to result in any cumulative impacts to socioeconomic resources affected by the

Macondo spill, nor should they have any impact on the previously conducted cumulative impact

analyses.

D.  Environmental Hazards

D.1 Geologic Hazards

The shallow hazards assessment included in this Supplemental EP, based on the shallow hazards

report by C&C Technologies, Inc. (2009), concludes that the wellsites are free of any major

geological hazards and are suitable for the proposed activities.  See Supplemental EP Section 6a

for supporting geological and geophysical information.

D.2 Severe Weather

Under most circumstances, weather is not expected to have any effect on the proposed

activities.  Extreme weather, including high winds, strong currents, and large waves, was

considered in the design criteria for the drillship.  High winds and limited visibility during a

severe storm could disrupt communication and support activities (vessel and helicopter traffic)

and make it necessary to suspend some activities on the drilling rig or drillship for safety reasons

until the storm or weather event passes.  In the event of a hurricane, procedures as outlined in

Shell’s Hurricane Evacuation Plan would be adhered to.

D.3 Currents and Waves

A rig‐based acoustic Doppler current profiler will be used to continuously monitor the current

beneath the rig.  Metocean conditions such as sea states, wind speed, ocean currents, etc. will

also be continuously monitored.  Under most circumstances, physical oceanographic conditions

are not expected to have any effect on the proposed activities.  Strong currents (e.g., caused by

Loop Current eddies and intrusions) and large waves were considered in the design criteria for

the drillship.  High waves during a severe storm could disrupt support activities (i.e., vessel and

helicopter traffic) and make it necessary to suspend some activities on the drilling rig or drillship

for safety reasons until the storm or weather event passes.

E.  Alternatives

No formal alternatives were evaluated in this EIA.  However, various technical and operational

options, including the location of the wellsites and the selection of a drilling unit, were

considered by Shell in developing the proposed action.  There are no other reasonable

alternatives to accomplish the goals of this project.   
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F.  Mitigation Measures

The proposed action includes numerous mitigation measures required by laws, regulations, and

the BOEMRE lease stipulations and NTLs.  The project will comply with all applicable Federal,

State, and local requirements concerning air pollutant emissions, discharges to water, and solid

waste disposal.  All project activities will be conducted under Shell’s OSRP and will include the

measures described in Supplemental EP Section 2j.  Additional pollution prevention measures,

beyond those required by 30 CFR Part 250, include the following:

• Health, safety, and environment (HSE) are the primary topics in pre‐tour and pre‐job safety

meetings.  The discussion around no harm to people or environment is a key mindset.  All

personnel are reminded daily to inspect work areas for safety issues as well as potential

pollution issues.

• All tools that come to and from the rig have their pollution pans inspected and cleaned, and

plug installation confirmed prior to leaving the dock and prior to loading on the boat.

• Preventive maintenance of rig equipment includes visual inspection of hydraulic lines and

reservoirs on a routine scheduled basis.

• All pollution pans on rig are inspected daily.

• Containment dikes are installed around all oil containment, drum storage areas, fuel vents,

and fuel storage tanks.

• All used oil and fuel is collected and sent to shore for recycling.

• Every drain on the rig is assigned a number on a checklist.  The checklist is used daily to

verify drain plugs are installed.

• All trash containers are checked and emptied daily, and trash containers are kept covered.  

Trash is collected in a compactor and sent to shore for recycling.

• The rig is involved in a recycling program for cardboard, plastic, paper, glass, and aluminum.

• Fuel hoses are changed on annual basis.

• Spill prevention fittings are installed on all liquid take‐on hoses.

• Waste paint thinner is recycled on board with a solvent to further reduce hazards of

shipping and storage.

• All equipment on board utilizes Envirorite hydraulic fluid as opposed to hydraulic oil.

• Shell has obtained International Organization for Standardization (ISO) 14001 certification.

• Shell will use low sulfur fuel (0.05% by weight) to reduce air pollutant impacts.

• Use of a DP drillship (no anchors) and high resolution sonar for well location planning will

minimize the potential for barrel impact.  Shell has prepared a BOEMRE‐approved plan for

“Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area” that applies

to anchoring and other operations that could cause a disturbance of a seafloor barrel.  The

plan specifies a safe stand‐off distance from the waste barrels of 10 m (33 ft) and requires

that anchor locations be surveyed with an ROV to maximize barrel avoidance.  In the

unlikely case that contact is suspected or has been made with any wastes from a barrel, the

plan specifies actions to be taken for the topside safety of personnel handling the

equipment.  The plan also outlines barrel impact reporting procedures.  
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G.  Consultation

No persons or agencies were consulted regarding potential impacts associated with the

proposed activities during the preparation of this EIA.

H.  Preparers

The EIA was prepared at the direction of Shell Offshore Inc. by its contractor, CSA International,

Inc.  Contributors included

• Sylvia Bellone (Regulatory Specialist, Shell Exploration & Production Co.);

• Lori Downs (Environmental Team Leader, Shell Exploration & Production Co.);

• Rob Kuehn (Environmental Engineer, Shell Exploration & Production Co.);

• Tracy Albert (Regulatory Specialist, Offshore Technical Compliance LLC);

• Derek Newberry (Mars B Business Opportunity Manager, Shell Exploration &

Production Co.);

• Robert Sloan (Mars B/West Boreas Subsurface Coordinator, Shell Exploration &

Production Co.); 

• Dougal Grant – Mars Geologist; Shell Exploration & Production Co.);

• Dubby Denham – Well Engineer; Shell Exploration & Production Co.);

• Cindy Chandool, Ph.D. (Senior Scientist, CSA International, Inc.);

• Carlyle Kalloo (Senior Scientist, CSA International, Inc.);

• Neal Phillips, Ph.D. (Senior Scientist, CSA International, Inc.);  

• Deborah Fawcett (Project Scientist II, CSA International, Inc.);

• Stephen Viada (Senior Scientist, CSA International, Inc.);

• Keith VanGraafeiland (GIS/Remote Sensing Specialist, CSA International, Inc.); and

• Danielle Johnson (Technical Editor, CSA International, Inc.).

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Section 19: Administrative Information

A. Exempted Information Description (Public Information Copies Only) 

The following attachments were excluded from the public information copies of this plan: 

1b. OCS Plan Information form – Bottom hole locations & proposed total depth 

2j. Blowout Scenario – confidential information for NTL 2010-N06 calculation 

3a. Geologic Description 

3b. Structure Contour Maps 

3c. Interpreted 2D or 3D seismic line(s) 

3d. Cross Section(s) 

3e. Shallow Hazards Report 

3f. Shallow Hazards Assessment – confidential data 

3g. High-Resolution Seismic Lines & Top Hole Progs 

3h. & 3i. Stratigraphic Column with Time vs. depth table 

 

B. Bibliography 

C&C report number 083985-084126: Archaeological and Hazard Report, Blocks 762-763, 806-807, and Vicinity, 

Mississippi Canyon Area, dated June 2009 

Hazards Report #1188-1062 prepared by Fugro-McClelland dated April 26, 1988. 

GEMS, #0403-643 entitled “Geologic and Stratigraphic Assessment Block 762, OCS-G 7957, Mississippi Canyon 

Area, Gulf of Mexico” dated August 26, 2003.