UNITED STATES GOVERNMENT MEMORANDUM

To: Public Information (MS 5030)

Plans Section, Office of Field 

Operations (MS 5231)

Public Information copy of Exploration Plan

Control # - N-09789

Type - Initial Exploration Plan

Lease(s) - OCS-G34467 Block - 943 Mississippi Canyon Area

Operator - Shell Offshore Inc.

Drill and suspend Wells A, B, C, and D

Not Found

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.

Ulunma Nwokeafor

Plan Coordinator

Description -

Rig Type -

Subject:

From:

April 28, 2014
Shell Offshore Inc.

P. O. Box 61933

New Orleans, LA 70161-1933

United States of America

Tel +1 504 425 7215

Fax +1 504 425 6747

Email sylvia.bellone@shell.com

March 18, 2014 Public Information Copy

Ms. Michelle Uli, Plans Supervisor 

Bureau of Ocean Energy Management 

1201 Elmwood Park Boulevard 

New Orleans, LA 70123-2394 

 

Attn: Plans Group GMG 290103 

SUBJECT: Initial Exploration Plan – Mississippi Canyon Block 943

 OCS-G 34467, Offshore Louisiana 

 

Dear Ms. Uli: 

 

In compliance with 30 CFR 550.211 and NTLs 2008-G04, 2009-G27 and 2010-N06, giving Exploration 

Plan guidelines, Shell Offshore Inc. (Shell) requests your approval of this Initial Exploration Plan 

requesting approval to drill four wells in Mississippi Canyon Block 943. Target date to commence drilling 

is July 2014. 

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 “Proprietary” 

and excluded from the Public Information copy of this submittal. The cost recovery receipt is attached to 

the Proprietary copy of the plan. 

We are providing the following report in support of this plan: Geologic, Stratigraphic and Archeological 

Assessment of Blocks 942 (OCS-G 24130) and 943 (OCS-G 34467) and Portions of Surrounding Blocks, Mississippi 

Canyon Area, Gulf of Mexico prepared by GEMS, Project No. 0513-2243a,b dated February 11, 2014.

Should you require additional information, please contact Tracy Albert at 504.425.4652 or 

tracy.albert@shell.com. 

Sincerely, 

Sylvia A. Bellone 

Page 1 Public Information Copy
SHELL OFFSHORE INC. 

INITIAL EXPLORATION PLAN 

for 

MISSISSIPPI CANYON BLOCK 943 

OCS-G 34467 

MARCH 2014 

PUBLIC INFORMATION COPY 

PREPARED BY: 

Tracy W. Albert 

Regulatory Specialist 

504.425.4652 

tracy.albert@shell.com

Page 2 Public Information Copy
REVISIONS TABLE

Date of Request Plan Section What was Corrected Date Resubmitted

3/24/2014 Section 2j

Section 7

Section 8

Section 9

Section 17

Add Form 0137, pgs 3-4

Removed dup. entry &

Added chemical product

Updated AQR 2018

Requested statement 

was in Plan Section 9.D

Add MS CZM

 3/27/2014

4/15/2014 Provided final copy of 

plan

 4/16/2014

Page 3 Public Information Copy
INITIAL EXPLORATION PLAN 

MISSISSIPPI CANYON BLOCK 943 

OCS-G 34467 

TABLE OF CONTENTS

1. PLAN CONTENTS 

2. GENERAL INFORMATION 

3. GEOLOGICAL AND GEOPHYSICAL 

4. HYDROGEN SULFIDE - 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 

 

 

 

Page 4 Public Information Copy
SECTION 1: PLAN CONTENTS

A. DESCRIPTION, OBJECTIVES & SCHEDULE

This Initial Exploration Plan (EP/Plan) describes the drilling activities Shell Offshore Inc. (Shell) plans to conduct 

with respect to Lease OCS-G 34467 located in Mississippi Canyon (MC) Block 943. 

Shell’s Plan, as detailed in this EP, is to use a either a dynamically positioned (DP) drillship, the M/V Noble Don 

Taylor or equivalent rig or a DP semi-submersible, the Noble Jim day or equivalent. The initial drilling activities 

are planned to commence on or about July 2014 and drilling is expected to take approximately 187 days per 

well. The timeframe to complete the initial drilling activity is an estimate based on the best available 

information regarding downhole conditions likely to be encountered while drilling and is not intended to be a 

limitation. Once the wells are drilled, a dry hole tree will be installed. Shell will complete and commence 

production under a separate DOCD. 

The selected rig will be equipped with state-of-the-art drilling and well control equipment. The rig will comply 

with the requirements in the Final Drilling Rules. The drilling activities will be supported by the vessels and 

aircraft as well as onshore support facilities as listed in Sections 14 and 15 of the EP. Shell has employed or 

contracted trained personnel to carry out its exploration activities. Shell is committed to local hire, contracting 

and 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 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 is designed to contain and respond to a spill that meets or 

exceeds the WCD detailed in Section 9 of this EP. The WCD does not take into account potential flow mitigating 

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

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 Maps. 

C. RIG SAFETY AND POLLUTION FEATURES: 

The selected rig 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 system, mud drain system, and oily water processing. 

Page 5 Public Information Copy
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 noncontaminated 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 consists 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) Mud Drain System 

 None 

4) 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 Section 18, EIA. 

Page 6 Public Information Copy
5) Lower Hull Bilge System 

• The main bilge system is designed to drain the pontoons. There are Goulds electrically driven, self 

priming centrifugal pumps - one for each main pump room. The aux pumps can 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; and 

• 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 activate when the water gets to a certain level they will automatically 

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. 

6) 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. 

7) 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. 

8) 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: 

 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. 

Page 7 Public Information Copy
 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. 

 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 

 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: 

 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. 

 The oily water collection tank overflow valve is closed. 

 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. 

 The BOP test area drains are normally lined-up to drain overboard. 

 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/monitored by the oil 

content detector, set at 15 ppm. 

 The solids control system is capable of being isolated for cuttings collection. 

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

 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. 

Page 8 Public Information Copy
D. Storage Tanks – Noble Don Taylor or similar DP Drillship:

Type of Storage 

Tank

Tank

Capacity (bbls)

Number of

Tanks

Total

Capacity (bbls)

Fluid

Gravity (Specific)

Fuel oil 2,889 4 11,556 Marine Diesel (0.91 

SG)

Fuel oil 3,225 4 12,900 Marine Diesel (0.91 

SG)

Fuel oil 2,887 4 11,548 Marine Diesel (0.91 

SG)

Fuel oil 2,680 4 10,720 Marine Diesel (0.91 

SG)

Fuel oil 178 8 1,424 Marine Diesel (0.91 

SG)

Storage Tanks – Noble Jim Day DP (or similar Semi-Submersible)

Type of Storage 

Tank

Type of 

Facility

Tank 

Capacity 

(Bbls)

Number of

Tanks

Total

Capacity (Bbls) Fluid Gravity (Specific)

Diesel Tank in 

stbd 1 80% fill in 

all hull tanks

Drilling Rig 3597 1 Marine Diesel (0.91 SG)

Diesel Tank in 

stbd 2

Drilling Rig 2713 1 Marine Diesel (0.91 SG)

Diesel Tank in 

stbd 3

Drilling Rig 3456 1 Marine Diesel (0.91 SG)

Diesel Tank in 

stbd 4

Drilling Rig 653 1 Marine Diesel (0.91 SG)

Diesel Tank in 

port 1

Drilling Rig 2090 1 Marine Diesel (0.91 SG)

Diesel Tank in 

port 2

Drilling Rig 1366 1 Marine Diesel (0.91 SG)

Diesel Tank in 

port 3

Drilling Rig 4787 1 Marine Diesel (0.91 SG)

Diesel Tank in 

port 4

Drilling Rig 3456 1 Marine Diesel (0.91 SG)

Total storage in 

hull tanks

Drilling Rig 22118 Marine Diesel (0.91 SG)

Diesel Settling 

Tanks

Drilling Rig 129 1 Marine Diesel (0.91 SG)

Diesel Settling 

Tanks

Drilling Rig 129 1 Marine Diesel (0.91 SG)

Diesel Settling 

Tanks

Drilling Rig 139 1 Marine Diesel (0.91 SG)

Diesel Settling 

Tanks

Drilling Rig 129 1 Marine Diesel (0.91 SG)

Page 9 Public Information Copy
E. Pollution Prevention Measures 

Pursuant to NTL No. 2008-G04 the proposed operations covered by this EP do not require Shell to specifically 

address the discharges of oil and grease from the rig during rainfall or routine operations. Nevertheless, 

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

F. Additional Measures

 

 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. 

 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. 

 Preventive maintenance of rig equipment includes visual inspection of hydraulic lines and reservoirs 

on 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 in 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. The trash containers are kept covered. Trash 

is disposed of in a compactor and shipped in via boat. 

 The rig is involved in a recycling program for cardboard, plastic, paper, glass, and aluminum. 

 Fuel hoses and SBM are changed on annual basis. 

 TODO spill prevention fittings are installed on all liquid take on hoses. 

 Waste paint thinner is recycled on board with a solvent still to reduce hazard of shipping and 

storage. 

 All equipment on board utilizes Envirorite hydraulic fluid as opposed to hydraulic oil. 

 Shell has obtained ISO14001 certification. 

 Shell uses low sulfur fuel. 

Page 10 Public Information Copy
Attachment 1A

Bathymetry and Surface Location

Page 11 Public Information Copy
Attachment 1C 

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

Bureau of Ocean Energy Management OMB Approval Expires: 12/31/2014 

OCS PLAN INFORMATION FORM 

General Information

Type of OCS Plan: X Exploration Plan (EP) DOCD

Company Name: Shell Offshore Inc. BOEM Operator Number: 0689

Address: P. O. Box 61933 Contact Person: Tracy Albert

New Orleans, LA 70161-1933 Phone Number: (504) 425-4652

E-Mail Address: tracy.albert@shell.com

Lease(s): G 34467 Area: MC Block(s): 943 Project Name (If Applicable): PowerNap

Objective(s): X Oil X Gas Sulphur Salt Onshore Base: Fourchon/Boothville Distance to Closest Land (Miles): 65

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) Pipeline appurtenance

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 a BOEM-designated high-probability archaeological area? Yes X No

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

Tentative Schedule of Proposed Activities

Proposed Activity Start Date End Date No. of Days

Drill and suspend well A 07/01/2014 01/04/2015 187

Drill and suspend well B 07/01/2015 01/04/2016 187

Drill and suspend well C 07/01/2016 01/04/2017 187

Drill and suspend well D 07/01/2017 01/04/2018 187

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

X DP Semisubmersible Other (Attach Description) Subsea manifold Floating production system

Drilling Rig Name (If Known): Noble Don Taylor or similar 

 Noble Jim Day 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

Form BOEM-0137 (December 2011-Supercedes all previous editions of form BOEM-0137 which may not be used.) 

 

Page 12 Public Information Copy
Attachment 1D

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): A Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 34467

Area Name Mississippi Canyon

Block No. 943

Blockline

Departures

(in feet)

N/S Departure: 986’ FSL

E/W Departure: 7,108’ FEL

Lambert X-Y 

coordinates

X: 990,812’

Y: 10,170,266’

Latitude/

Longitude

Latitude 28.0111767

Longitude -89.0137157

TVD (Feet): MD (Feet): Water Depth (Feet): 4,211’

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

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. 2501 et seq.) requires us to inform you that 

BOEM collects this information as part of an applicant’s Exploration Plan or Development Operations Coordination Document submitted for 

BOEM 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 550.197. 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. Responses are mandatory (43 U.S.C. 1334). 

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 600 hours with an accompanying EP, or 700 hours with an accompanying DPP or DOCD, 

including the time for reviewing instructions, gathering and maintaining data, and completing and reviewing the forms associated with subpart 

B. Direct comments regarding the burden estimate or any other aspect of this form to the Information Collection Clearance Officer, Bureau of 

Ocean Energy Management, 381 Elden Street, Herndon, VA 20170.

Form BOEM-0137 (December 2011-Supercedes all previous editions of form BOEM-0137 which may not be used.)

Page 13 Public Information Copy
Attachment 1E

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): B Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 34467

Area Name Mississippi Canyon

Block No. 943

Blockline

Departures

(in feet)

N/S Departure: 364’ FSL

E/W Departure: 2,612’ FEL

Lambert X-Y 

coordinates

X: 995,308’

Y: 10,169,644’

Latitude/

Longitude

Latitude 28.0096697

Longitude -89.9997538

TVD (Feet): MD (Feet): Water Depth (Feet): 4,227’

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

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. 2501 et seq.) requires us to inform you that 

BOEM collects this information as part of an applicant’s Exploration Plan or Development Operations Coordination Document submitted for 

BOEM 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 550.197. 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. Responses are mandatory (43 U.S.C. 1334). 

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 600 hours with an accompanying EP, or 700 hours with an accompanying DPP or DOCD, 

including the time for reviewing instructions, gathering and maintaining data, and completing and reviewing the forms associated with subpart 

B. Direct comments regarding the burden estimate or any other aspect of this form to the Information Collection Clearance Officer, Bureau of 

Ocean Energy Management, 381 Elden Street, Herndon, VA 20170.

Form BOEM-0137 (December 2011-Supercedes all previous editions of form BOEM-0137 which may not be used.)

Page 14 Public Information Copy
Attachment 1F

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): C Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 34467

Area Name Mississippi Canyon

Block No. 943

Blockline

Departures

(in feet)

N/S Departure: 1,535’ FSL

E/W Departure: 861’ FEL

Lambert X-Y 

coordinates

X: 997,059’

Y: 10,170,815’

Latitude/

Longitude

Latitude 28.0129687

Longitude -89.9943880

TVD (Feet): MD (Feet): Water Depth (Feet): 4,276’

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

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. 2501 et seq.) requires us to inform you that 

BOEM collects this information as part of an applicant’s Exploration Plan or Development Operations Coordination Document submitted for 

BOEM 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 550.197. 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. Responses are mandatory (43 U.S.C. 1334). 

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 600 hours with an accompanying EP, or 700 hours with an accompanying DPP or DOCD, 

including the time for reviewing instructions, gathering and maintaining data, and completing and reviewing the forms associated with subpart 

B. Direct comments regarding the burden estimate or any other aspect of this form to the Information Collection Clearance Officer, Bureau of 

Ocean Energy Management, 381 Elden Street, Herndon, VA 20170.

Form BOEM-0137 (December 2011-Supercedes all previous editions of form BOEM-0137 which may not be used.)

Page 15 Public Information Copy
Attachment 1G

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): D Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 34467

Area Name Mississippi Canyon

Block No. 943

Blockline

Departures

(in feet)

N/S Departure: 2,869’ FSL

E/W Departure: 3,587’ FEL

Lambert X-Y 

coordinates

X: 994,333’

Y: 10,172,149’

Latitude/

Longitude

Latitude 28.0165143

Longitude -89.0029022

TVD (Feet): MD (Feet): Water Depth (Feet): 4,270’

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

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. 2501 et seq.) requires us to inform you that 

BOEM collects this information as part of an applicant’s Exploration Plan or Development Operations Coordination Document submitted for 

BOEM 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 550.197. 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. Responses are mandatory (43 U.S.C. 1334). 

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 600 hours with an accompanying EP, or 700 hours with an accompanying DPP or DOCD, 

including the time for reviewing instructions, gathering and maintaining data, and completing and reviewing the forms associated with subpart 

B. Direct comments regarding the burden estimate or any other aspect of this form to the Information Collection Clearance Officer, Bureau of 

Ocean Energy Management, 381 Elden Street, Herndon, VA 20170.

Form BOEM-0137 (December 2011-Supercedes all previous editions of form BOEM-0137 which may not be used.)

Page 16 Public Information Copy
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. Prior to beginning exploration operations, an Application for Permit to Drill will be 

submitted and approved by the Bureau of Safety and Environmental Enforcement (BSEE). 

B. Drilling Fluids 

See Section 7, Tables 7A and 7B. 

C. Production

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

of DOCDs. 

D. Oil Characteristics 

Information regarding oil characteristics is not included in this EP as such information is only necessary in the 

case of DOCDs. 

E. New Or Unusual Technology

Shell is not proposing to use new or unusual technology as defined in 30 CFR 250.200 to carry out the proposed 

activities in this EP. 

F. Bonding

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

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

Bonds;” and additional security under National NTL No. 2008-N07, “Supplemental Bond Procedures.”

G. Oil Spill Financial Responsibility (OSFR)

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

facilities proposed in the EP according to 30 CFR Part 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., 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. 

Page 17 Public Information Copy
J. Summary

This Section 2j was prepared by Shell pursuant to the guidance provided in the BOEM’s NTL 2010-N06 with 

respect to blowout and worst case discharge (WCD) scenario descriptions. Shell intends to comply with all 

applicable laws, regulations, rules and Notices to Lessees. 

Shell focuses on an integrated, three-pronged approach to a blowout, including prevention, intervention, 

containment, and recovery. 

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

Significant effort goes into design and execution of wells and into building and maintaining staff 

competence. Shell continues to invest independently in R&D to improve safety and reliability of 

our well systems. 

2. Shell is a founding member of the MWCC, which provides robust well containment (shut-in and 

controlled flow) capabilities. Additionally, Shell is investing in R&D to improve containment 

systems. 

3. As outlined in Shell’s OSRP, and detailed in EP Section 9a (ii), Shell has contracts with OSROs to 

provide the resources necessary to respond to this WCD scenario. The capabilities for on-water 

recovery, aerial and subsea dispersant application, in-situ burning, and nighttime monitoring and 

tracking have been significantly increased. 

The WCD blowout scenario for this plan is calculated for the MC 943 Well A location penetration of the target 

interval and is based on the guidelines outlined in NTL 2010-N06 along with subsequent Frequently Asked 

Questions (FAQ). Shell’s Regional OSRP (April 2013) is based on MC-391 Well 1 as the WCD well. In the 

unlikely event of a spill, Shell’s Regional OSRP is designed to contain and respond to a spill that exceeds this 

WCD. This WCD does not take into account potential flow mitigating factors such as well bridging, 

obstructions in wellbore, reservoir barriers, and early intervention including containment capabilities. 

Uncontrolled blowout (volume first day) 175,000 bbl oil

Uncontrolled blowout rate (first 30-days average daily rate) 165,000 bopd

Duration of flow (days) based on relief well 203 days

Total volume of spill (bbls) for 203 days 32 MMBO

Table 2.1. PowerNap Worst Case Discharge Summary 

The exploration prospect is located approximately 65 statute miles south-southeast of the nearest Louisiana 

shoreline in the Gulf of Mexico, in water depths of 4186-4708’ across the prospect. The MC943 A well is 

expected to have the highest flow rates. The alternate well locations (B, C, D) were also evaluated; however, 

their flow rates are lower than the WCD calculated for the MC 943 A well. 

1) Purpose 

Pursuant to 30 CFR 250.213(g), 250.219, 250.250, and NTL 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 regional formation of offset well data and 

seismic data. 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.

Page 18 Public Information Copy
2) Background 

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

requested by NTL No. 2010-N06 in response to the explosion and sinking of the MODU Deepwater Horizon 

and the resulting subsea well blowout and recovery operations of the exploration well at the MC-252 

Macondo location. 

3) Information Requirements 

a) Blowout scenario 

All well locations addressed in this EP were assessed for WCD. The MC-943 well from the A location 

represents the highest flow potential. The A well penetrates the Miocene objective interval as outlined in the 

Geological and Geophysical Information Section of the EP using a subsea wellhead system, conductor, 

surface and intermediate casing program, and using a DP MODU with a marine riser and subsea blowout 

preventer (BOP). A hydrocarbon influx and a well control event are modeled to occur from reservoirs in the 

objective interval. The modeled blowout results in unrestricted flow from the well at the seafloor, which 

represents the WCD (no restrictions in 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-943 

Facility Designation MODU 

Distance to Nearest Shoreline (Statute miles) 65

Uncontrolled blowout (volume first day) 175,000 bbl oil

Uncontrolled blowout rate (first 30-days average daily rate) 165,000 bopd 

Table 2.2 Estimated Flow Rates of a Potential Blowout 

c) Total volume and maximum duration of the potential blowout 

Duration of flow (days) 203 days total duration to drill relief well 

(14 days rig demobilization, 4 days rig mobilization, 155 days spud 

to TD, 30 days ranging). 

Total volume of spill (bbls) 32 MMBO based on 203 days flowing. 

Note: From GAP/Prosper/MBAL model

Table 2.3 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 

2010-N06 calculations for 24-hour and 30-day rates as well as maximum duration volumes. 

Page 19 Public Information Copy
d) Assumptions and calculations used in determining the worst case discharge (Proprietary) 

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 the outflow rates. However, this 

WCD scenario does not include any bridging. 

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 Final Drilling Safety Rule with respect to 

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

The rig that will be used to drill the well will be equipped with BOP stack that complies with Shell and BSEE 

standards. 

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. 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 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 2014 – 2018 timeframe. The dynamically positioned rigs under contract, the Noble 

Jim Day, Noble Globetrotter I, and the Noble Bully I will be the preferred rigs for blowout intervention work. 

However, moored rigs, like the Transocean Deepwater Nautilus, 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. 

Page 20 Public Information Copy
Shell’s current contracted rigs capable of operating at PowerNap water depths and reservoir depths without 

constraints are in the following table: 

Rig Name Rig Type

Noble Jim Day Dynamically positioned semisubmersible

Noble Globetrotter I Dynamically positioned drillship

Noble Bully I Dynamically positioned drillship

Transocean Deepwater Nautilus Moored semisubmersible

Table 2.4 Shell contracted rigs capable at PowerNap 

Future modifications may change the rig’s capability. Rig capabilities need to be assessed on a work scope 

specific basis. 

h) Time taken to contract a rig, move it onsite, and drill a relief well 

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

Table 2.4 lists the Shell contracted rigs capable of operating at PowerNap. 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 an 

additional 4 days transit to mobilize to the relief well site depending on distance to the site. The relief well will 

take approximately 155 days to drill down to the last casing string above the blowout zone, plus 

approximately 30 days for precision ranging activity to intersect the blowout well bore. The total time to 

mobilize and drill a relief well would be 203 days for the Power Nap 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 mooring activity is not expected 

to delay initiation of relief well drilling operations. Shell has deepwater anchor handlers on long term contract 

to support its moored rigs. 

It is not possible to drill relief wells from any existing platforms due to the distance to reach the sub-surface. 

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 undefined 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. 

Page 21 Public Information Copy
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 PowerNap. 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 monitored 24/7 virtually by onshore teams 

consisting of geoscientists, petrophysicists, well engineers, and 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 Foremen 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, 

Page 22 Public Information Copy
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, 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 2f 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 2014-2018 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 Regional OSRP 

All proposed PowerNap locations were evaluated and Location A was determined to have the greatest WCD 

volume. Shell has designed a response program (Regional OSRP) based upon a regional capability of 

responding to a range of spill volumes, from small operational spills up to and including the WCD from a 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. 

Page 23 Public Information Copy
SECTION 3: GEOLOGICAL & GEOPHYSICAL INFORMATION

A. Geological Description

Proprietary Data 

B. Structure contour map

Proprietary Data

C. Interpreted 2D and/or 3D Seismic line(s)

Proprietary Data

D. Geological Structure Cross-section(s)

Proprietary Data

E. Shallow Hazards Report

Geoscience Earth and Marine Services, Inc. (GEMS), Geologic, Stratigraphic and Archaeological 

Assessment of Blocks 942 (OCS G-24130), 943 (OCS G-34467), and Portions of Surrounding Blocks, 

Mississippi Canyon Area, Gulf of Mexico. Project No. 0513-2243a,b, dated February 11, 2014. 

C&C Technologies, Archaeological Assessment Report, Blocks 895-898, 939-942, & 983-986, Mississippi 

Canyon Area. Project No. 072657-072954, dated October, 2007. Data: AUV Side Scan Sonar and SubBottom Profiler 

F. Shallow Hazards Assessment

See Section 6 for Shallow Hazards Assessment. 

G. High-Resolution Seismic Lines

Proprietary Data

H & I Stratigraphic Column with Time vs depth table

Proprietary Data

Page 24 Public Information Copy
SECTION 4: HYDROGEN SULFIDE

A. Concentration 

 0 ppm. 

B. Classification

 Based on 30 CFR 550.215, Shell requests that the Regional Supervisor, Field Operations, classify the area in 

the proposed drilling operations as an area where the absence of H2S is confirmed. 

 

C. H2S Contingency Plan

Shell is not required to provide an H2S Contingency Plan with the Application for Permit to Drill before 

conducting the proposed activities. 

D. 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.

Page 25 Public Information Copy
SECTION 5: MINERALS RESOURCE CONSERVATION

Information regarding Mineral Resource Conservation is not included in this EP as such information is only 

necessary in the case of DOCDs. 

Page 26 Public Information Copy
. 

SECTION 6: BIOLOGICAL, PHYSICAL AND SOCIOECONOMIC INFORMATION

Mississippi Canyon Blocks 943 

Shallow Hazards Report and Data: 

Geoscience Earth and Marine Services, Inc. (GEMS), Geologic, Stratigraphic and Archaeological Assessment of 

Blocks 942 (OCS G-24130), 943 (OCS G-34467), and Portions of Surrounding Blocks, Mississippi Canyon Area, 

Gulf of Mexico. Project No. 0513-2243a,b, dated February 11, 2014. Data: AUV Side Scan Sonar, Sub 

Bottom Profiler, and frequency enhanced 3-D Seismic 

Archaeological Reports and Data: 

Geoscience Earth and Marine Services, Inc., Geologic, Stratigraphic and Archaeological Assessment of Blocks 

942 (OCS G-24130), 943 (OCS G-34467), and Portions of Surrounding Blocks, Mississippi Canyon Area, Gulf 

of Mexico. Project No. 0513-2243a,b, dated January 24, 2013. Data: AUV Side Scan Sonar, Sub Bottom 

Profiler, and frequency enhanced 3-D Seismic 

C&C Technologies, Archaeological Assessment Report, Blocks 895-898, 939-942, & 983-986, Mississippi 

Canyon Area. Project No. 072657-072954, dated October, 2007. Data: AUV Side Scan Sonar and SubBottom Profiler 

Proposed Locations and Coordinates: 

Proposed 

Location X Coordinate Y coordinate FNL/FSL FEL/FWL Water Depth

MC 943 A 990,812 10,170,266 986’ FSL 7108’ FEL 4211’

MC 943 B 995,308 10,169,644 364’ FSL 2612’ FEL 4227’

MC 943 C 997,059 10,170,815 1535’ FSL 861’ FEL 4276’

MC 943 D 994,333 10,172,149 2869’ FSL 3587’ FEL 4270’

Coordinates are in UTM 16, NAD27 

Site Assessment, MC 943, Proposed Location A 

Mississippi Canyon 943, Proposed Location A is located in a water depth of approximately 4211 feet. 

Proposed Location A lies along the flank of a seafloor ridge. Buried faults are identified 195’ below the 

mudline, seafloor offset is 950’ north of Proposed Location A. Proposed Location A will not intersect this or 

any faulting in the shallow stratigraphy. There is no other evidence of seafloor or near-surface faulting, 

slumping amplitudes or fluid expulsion features within 2000 feet of MC 943, Proposed Location A . 

The stratigraphy at the site of MC 943, Proposed Location A consists of: 

• Unit 1 (Seafloor – 452’ BML) - 5’ transparent drape of very soft silty clays, 200’ of layered soft 

hemipelagic silty clays, 247’ stratified pelagic and hemipelagic muds with thin mud-rich MTD’s

• Unit 2 (452’ – 1194’ BML) – 416’ hemipelagic sediments layers with thin, discontinuous MTD’s, 326’ 

mud-rich MTD’s with possible sand pockets

• Unit 3 - Blue Unit (1194’ – 1929’ BML) – 113’ layered turbidites of clay, silt and thin sand layers, 

409’ Ursa Canyon-fill sediments of silts, clays and thin sand layers and pockets, 213’ of MTD’s of sand, silt 

and clay 

• Unit 4 (1929’ – 2249’ BML) – 320’ discontinuous, mud-rich MTD’s

• Unit 5 (2249’ – 2932’ BML) – 683’ discontinuous, mud-rich MTD’s

• Unit 6 – Orange Unit (2932’ – 4205’ BML) – 298’ slope fan sequence of clays, silts with scattered 

sand layers and pockets, 283’ MTD’s with scattered small channels of sand, silt and clay, 692’ mud-rich MTD’s

• Unit 7 (4205’ – 5503’ BML) – 1298’ layered turbidites inter-layered with clay, silt and sand 

Shallow Water Flow Potential: 

 Negligible Potential – Seafloor – 868’ BML

 Low Potential – 868’ – 1194’ BML

 High Potential – 1194’ – 1929’ BML

Page 27 Public Information Copy
 Low Potential – 1929’ – 2932’ BML

 High Potential – 2932’ – 3230’ BML

 Moderate Potential – 3230’ – 3513’ BML

 Low Potential - 3513’ – 5503’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor – 868’ BML

 Low Potential – 868’ – 5503’ BML

An amplitude event in Unit 6 (Orange Unit, 2932’ – 4205’ BML) is identified 465’ north-northwest of Proposed 

Location A. Proposed Location A will not penetrate this amplitude. 

Benthic/Anchor Assessment, MC 943, Proposed Location A (no anchors – DP Vessel) 

Mississippi Canyon 943, Proposed Location A is located in a water depth of approximately 4211 feet. 

Proposed Location A lies along the flank of a subtle seafloor ridge. 

A seafloor fault is identified 950’ north of Proposed Location A. There is no other evidence of seafloor or 

near-surface faulting, slumping, amplitudes or fluid expulsion features within 2000’ of Proposed Location A. 

Proposed Location A will not disturb any high-density areas of benthic communities. 

The following table consisting of 9 targets is a listing of marine avoidance zones identified within 2000’ of MC 

943, Proposed Location A. 

Target No. X Coordinate Y Coordinate

Distance to 

Target

Direction 

from 

Prop Loc A

To Target

Avoidance

2013-467 989569.73 10169766.76 1338.83’ Northeast 100’

2013-474 989872.25 10169151.92 1457.50’ Northeast 100’

2013-471 990641.40 10168799.28 1476.61’ Northeast 100’

2013-424 991265.98 10171677.51 1482.72’ Southwest 100’

2013-475 990159.18 10168646.73 1745.91’ Northeast 100’

2013-388 990336.26 10171972.46 1771.53’ Southeast 100’

2013-375 990301.76 10172034.60 1840.73’ Southeast 100’

2013-485 991130.85 10168446.82 1846.91’ Southwest 100’

2013-390 989873.59 10171963.69 1939.78’ Southeast 100’

Currently, there are no flowlines or umbilicals located within 2000’ of Proposed Location A.

Based on a high-resolution geophysical survey consisting of AUV Side-Scan Sonar and Sub-Bottom Profiler, 

frequency enhanced 3-D Seismic, Enhanced Surface Renderings (ESR’s) and ESR’s with amplitudes applied, 

MC 943, Proposed Location A appears suitable for the planned activity. 

Site Assessment, MC 943, Proposed Location B 

Mississippi Canyon 943, Proposed Location B is located in a water depth of approximately 4227 feet. 

Proposed Location B lies along the flank of a subtle seafloor ridge. Buried faults are identified 100’ below the 

mud line, seafloor offset is 1300’ north of Proposed Location B. Proposed Location B will not intersect this or 

any faulting in the shallow stratigraphy. There is no other evidence of seafloor or near-surface faulting, 

slumping amplitudes or fluid expulsion features within 2000 feet of MC 943, Proposed Location B. 

The stratigraphy at the site of MC 943, Proposed Location B consists of: 

• Unit 1 (Seafloor – 428’ BML) - 5’ transparent drape of very soft silty clays, 200’ layered soft 

hemipelagic silty clays, 223’ stratified pelagic and hemipelagic muds with thin mud-rich MTD’s

• Unit 2 (428’ – 1149’ BML) – 570’ hemipelagic sediments layers with thin, discontinuous MTD’s, 151’ 

mud-rich MTD’s with possible sand pockets

• Unit 3 - Blue Unit (1149’ – 1910’ BML) – 395’ Ursa Canyon-fill sediments of silts, clays and thin sand 

layers and pockets, 366’ of MTD’s of sand, silt and clay

• Unit 4 (1910’ – 2079’ BML) – 169’ discontinuous, mud-rich MTD’s

• Unit 5 (2079’ – 2692’ BML) – 613’ discontinuous, mud-rich MTD’s

Page 28 Public Information Copy
• Unit 6 – Orange Unit (2692’ – 3948’ BML) – 662’ slope fan sequence of clays, silts with scattered 

sand layers and pockets, 594’ mud-rich MTD’s

• Unit 7 (3948’ – 5436’ BML) – 1488’ layered turbidites inter-layered with clay, silt and sand. 

Shallow Water Flow Potential: 

 Negligible Potential – Seafloor – 998’ BML

 Low Potential – 998’ – 1149’ BML

 High Potential – 1149’ – 1910’ BML

 Low Potential – 1910’ – 2692’ BML

 High Potential – 2692’ – 3354’ BML

 Low Potential – 3354’ – 5436’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor – 998’ BML

 Low Potential – 998’ - 5436’ BML

A buried amplitude in Unit 7 (3948’ – 5436’ BML) is identified 500’ southwest of Proposed Location B. 

Proposed Location B will not penetrate this amplitude. 

Benthic/Anchor Assessment, MC 943, Proposed Location B (no anchors – DP Vessel) 

Mississippi Canyon 943, Proposed Location B is located in a water depth of approximately 4227 feet. 

Proposed Location B lies along the flank of a subtle seafloor ridge. 

A seafloor fault is identified 1300’ north of Proposed Location B, approximately 100’ BML. There is no other 

evidence of seafloor or near-surface faulting, slumping, amplitudes or fluid expulsion features within 2000’ of 

Proposed Location B. Proposed Location B will not disturb any high-density areas of benthic communities. 

The following table consisting of 5 targets is a listing of marine avoidance zones identified within 2000’ of MC 

943, Proposed Location B. 

Target No. X Coordinate Y Coordinate

Distance to 

Target

Direction 

from 

Prop Loc B

To Target

Avoidance

2013-450 995375.92 10170383.69 742.80’ Southwest 100’

2013-468 995259.62 10168797.53 847.85’ Northeast 100’

2013-483 995816.99 10168443.56 1303.89’ Northwest 100’

2013-438 994687.32 10171051.54 1538.31’ Southeast 100’

2013-405 996336.25 10171355.84 1996.92’ Southwest 100’

Currently, there are no flowlines or umbilicals located within 2000’ of Proposed Location B. 

Based on a high-resolution geophysical survey consisting of AUV Side-Scan Sonar and Sub-Bottom Profiler, 

frequency enhanced 3-D Seismic, Enhanced Surface Renderings (ESR’s) and ESR’s with amplitudes applied, 

MC 943, Proposed Location B appears suitable for the planned activity. 

Site Assessment, MC 943, Proposed Location C 

Mississippi Canyon 943, Proposed Location C is located in a water depth of approximately 4276 feet. 

Proposed Location C lies along the flank of a subtle seafloor ridge. Buried faults are identified 50’-120’ below 

the mud line, seafloor offset is 1750’ east of Proposed Location C. Proposed Location C will not intersect 

these or any other faulting in the shallow stratigraphy. There is no other evidence of seafloor or near-surface 

faulting, slumping amplitudes or fluid expulsion features within 2000 feet of MC 943, Proposed Location C. 

The stratigraphy at the site of MC 943, Proposed Location C consists of: 

• Unit 1 (Seafloor – 412’ BML) - 8’ transparent drape of very soft silty clays, 190’ layered soft 

hemipelagic silty clays, 214’ stratified pelagic and hemipelagic muds with thin mud-rich MTD’s

Page 29 Public Information Copy
• Unit 2 (412’ – 1069’ BML) – 483’ hemipelagic sediments layers with thin, discontinuous MTD’s, 174’ 

mud-rich MTD’s with possible sand pockets 

• Unit 3 - Blue Unit (1069’ – 1827’ BML) – 225’ MTD’s mixture of sand, silt and clay, 533’ Ursa 

Canyon-fill sediments of silts, clays and thin sand layers and pockets 

• Unit 4 (1827’ – 1931’ BML) – 104’ discontinuous, mud-rich MTD’s

• Unit 5 (1931’ – 2527’ BML) – 596’ discontinuous, mud-rich MTD’s

• Unit 6 – Orange Unit (2527’ – 3698’ BML) – 575’ slope fan sequence of clays, silts with scattered 

sand layers and pockets, 596’ mud-rich MTD’s with scattered small channels, mix of sand, silt and clay 

• Unit 7 (3698’ – 5381’ BML) – 1683’ layered turbidites inter-layered with clay, silt and sand 

Shallow Water Flow Potential: 

 Negligible Potential – Seafloor – 895’ BML

 Low Potential – 895’ – 1069’ BML

 High Potential – 1069’ – 1827’ BML

 Low Potential – 1827’ – 2527’ BML

 High Potential – 2527’ – 3102’ BML

 Moderate Potential – 3102’- 3698’ BML

 Low Potential - 3698’ – 5381’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor – 895’ BML

 Low Potential – 895’ - 5381’ BML

A buried amplitude in Unit 6 (Orange Unit 2527’ – 3698’ BML) is identified 300’ southwest of Proposed 

Location C. Proposed Location C will not penetrate this amplitude. 

Benthic/Anchor Assessment, MC 943, Proposed Location C (no anchors – DP Vessel) 

Mississippi Canyon 943, Proposed Location C is located in a water depth of approximately 4276 feet. 

Proposed Location C lies along the flank of a subtle seafloor ridge. 

A seafloor fault is identified 1750’east of Proposed Location C. There is no other evidence of seafloor or nearsurface faulting, slumping, amplitudes or fluid expulsion features within 2000’ of Proposed Location C. 

Proposed Location C will not disturb any high-density areas of benthic communities. 

The following table consisting of 4 targets is a listing of marine avoidance zones identified within 2000’ of MC 

943, Proposed Location C. 

Target No. X Coordinate Y Coordinate

Distance to 

Target

Direction 

from 

Prop Loc C

To Target

Avoidance

2013-400 997424.79 10171372.56 666.84’ Southwest 100’

2013-440 997872.94 10171028.93 841.58’ Southwest 100’

2013-405 996336.25 10171355.84 902.70’ Northeast 100’

2013-450 99375.92 10170383.69 1737.47’ Southeast 100’

Currently, there are no flowlines or umbilicals located within 2000’ of Proposed Location C. 

Based on a high-resolution geophysical survey consisting of AUV Side-Scan Sonar and Sub-Bottom Profiler, 

frequency enhanced 3-D Seismic, Enhanced Surface Renderings (ESR’s) and ESR’s with amplitudes applied, 

MC 943, Proposed Location C appears suitable for the planned activity. 

Site Assessment, MC 943, Proposed Location D 

Mississippi Canyon 943, Proposed Location D is located in a water depth of approximately 4270 feet. 

Proposed Location D lies along the flank of a subtle seafloor ridge. Buried faults are identified 120-190’ 

Page 30 Public Information Copy
below the mud line, seafloor offset is 825’ southwest of Proposed Location D. Proposed Location D will not 

intersect these or any other faulting in the shallow stratigraphy. There is no other evidence of seafloor or 

near-surface faulting, slumping amplitudes or fluid expulsion features within 2000 feet of MC 943, Proposed 

Location D. 

The stratigraphy at the site of MC 943, Proposed Location D consists of: 

• Unit 1 (Seafloor – 439’ BML) - 5’ transparent drape of very soft silty clays, 200’ layered soft 

hemipelagic silty clays, 234’ stratified pelagic and hemipelagic muds with thin mud-rich MTD’s

• Unit 2 (439’ – 1053’ BML) –440’ hemipelagic sediments layers with thin, discontinuous MTD’s, 174’ 

mud-rich MTD’s with possible sand pockets 

• Unit 3 - Blue Unit (1053’ – 1919’ BML) – 866’ Ursa Canyon-fill sediments of silts, clays and thin sand 

layers and pockets, 153’ discontinuous mud-rich MTD’s

• Unit 4 (1919’ – 2072’ BML) – 153’ discontinuous, mud-rich MTD’s

• Unit 5 (2072’ – 2723’ BML) – 651’ discontinuous, mud-rich MTD’s

• Unit 6 – Orange Unit (2723’ – 3947’ BML) – 650’ slope fan sequence of clays, silts with scattered 

sand layers and pockets, 574’ mud-rich MTD’s with scattered small channels, mix of sand, silt and clay 

• Unit 7 (3947’ –5422’ BML) – 1475’ layered turbidites inter-layered with clay, silt and sand 

Shallow Water Flow Potential: 

 Negligible Potential – Seafloor – 879’ BML

 Low Potential – 879’ – 1053’ BML

 High Potential – 1053’ – 1919’ BML

 Low Potential – 1919’ – 2723’ BML

 High Potential – 2723’ – 3373’ BML

 Low Potential - 3373’ – 5422’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor – 879’ BML

 Low Potential – 879’ - 5422’ BML

A buried amplitude in Unit 7 (3947’ – 5422’ BML) is identified 700’ northwest of Proposed Location D. 

Proposed Location D will not penetrate this amplitude. 

Benthic/Anchor Assessment, MC 943, Proposed Location D (no anchors – DP Vessel) 

Mississippi Canyon 943, Proposed Location D is located in a water depth of approximately 4270 feet. 

Proposed Location D lies along the flank of a subtle seafloor ridge. 

A seafloor fault is identified 825’ southwest of Proposed Location D. There is no other evidence of seafloor or 

near-surface faulting, slumping, amplitudes or fluid expulsion features within 2000’ of Proposed Location D. 

Proposed Location D will not disturb any high-density areas of benthic communities. 

The following table consisting of 10 targets is a listing of marine avoidance zones identified within 2000’ of 

MC 943, Proposed Location D. 

Target No. X Coordinate Y Coordinate

Distance to 

Target

Direction 

from 

Prop Loc D

To Target

Avoidance

2013-381 993989.42 10172424.86 440.62’ Southeast 100’

2013-371 994524.86 10172603.25 493.20’ Southwest 100’

2013-366 994359.46 10172649.65 501.35’ Southwest 100’`

2013-418 994948.00 10171714.14 753.21’ Northwest 100’

2013-421 995183.94 10171692.61 965.60’ Northwest 100’

2013-438 994687.32 1017105.54 1153.24’ Northwest 100’

2013-347 994674.39 10173358.12 1256.39’ Southwest 100’

2013-361 994362.99 10173634.16 1485.46’ Southwest 100’

2013-349 993365.33 10173352.60 1544.36’ Southeast 100’

2013-385 992474.37 10172209.41 1859.61’ Southeast 100’

Page 31 Public Information Copy
Currently, there are no flowlines or umbilicals located within 2000’ of Proposed Location D.

Based on a high-resolution geophysical survey consisting of AUV Side-Scan Sonar and Sub-Bottom Profiler, 

frequency enhanced 3-D Seismic, Enhanced Surface Renderings (ESR’s) and ESR’s with amplitudes applied, 

MC 943, Proposed Location D appears suitable for the planned activity. 

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 No. 2008-G06, Remotely Operated Vehicle Surveys in Deepwater, 

Walker Ridge Block 95 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 Endanger 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

Page 32 Public Information Copy
There are 28 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

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

Page 33 Public Information Copy
I. Archaeological Report

Arch Statements 

2013 Report (GEMS) 

The archaeological assessment identified 637 unidentified sonar contacts within the 2013 survey area and 

106 unidentified sonar contacts within the 2007 survey area covered by the AUV data sets. The unidentified 

contacts are likely man-made debris. None of these targets is believed to have a cultural significance and no 

avoidance zones have been assigned. However, a disused Industrial Waste Dumpsite is northwest of the 

study area. Some of the debris within the AUV survey area may represent material intended the dumpsite. A 

100-ft (30.5 m) geohazard avoidance is recommended for all unidentified sonar contacts in the area. 

2007 Report (C&C Technologies) 

Data assessment of Blocks 895-898, 939-942, and 983-986, Mississippi Canyon Area for the Vito Prospect 

revealed 106 contacts. The unidentified contacts are interpreted as debris from modern shipping and lease 

activities or are geologic in origin. None of the unidentified contacts are recommended for an archaeological 

avoidance based on their acoustic signatures. 

It is possible shipwrecks exist undetected or unidentified within the survey area. If wood beams, planking, 

ceramics, or other possible cultural materials are encountered during lease development, the MMS 

archaeologists must be contacted within 48 hours for an assessment of any antiquities. In this event, no 

activities should be conducted near the area of discovery until advised by the appropriate MMS personnel. 

J. Air and Water Quality Information

Pursuant to NTL No. 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 No. 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. 

Page 34 Public Information Copy
ESR for MC 943 Well A

Page 35 Public Information Copy
ESR for MC 943 Well B

Page 36 Public Information Copy
ESR for MC 943 Well C

Page 37 Public Information Copy
ESR for MC 943 Well D

Page 38 Public Information Copy
SECTION 7: WASTE AND DISCHARGE INFORMATION

A. Discharge to GOM or Downhole

Note: Please specify if the amount reported is a total or per well amount Power Nap

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 pip

Water-based drilling fluid barite, additives, mud 30,000 bbls / well 3,500 bbls / day

Overboard and seafloor dis

marine riser insta

Cuttings wetted with water-based fluid

cuttings coated with water based drilling 

mud 1,590 bbls / well 200 bbls / day Sea bed during riserl

Cuttings wetted with synthetic-based fluid 

Cuttings generated while using synthetic based drilling fluid. 8,295 bbls / well 165 bbs / day

Overboard discharge line b

level 

Synthetic based drilling fluid adhering to washed drill cuttings

Synthetic based drilling fluid adhering to washed drill cuttings 290 bbls / well 6 bbls / day

Overboard discharge line b

level 

Will humans be there? If yes, expect conventional waste

EXAMPLE: Sanitary waste water X liter/person/day NA chlorinate and dis

Domestic waste (kitchen water, shower water) grey water 39,000 bbls/well 203 bbls / day

Grinded to less than 25 mm discharge overboard 

Sanitary waste (toilet water) treated sanitary waste 6,000 bbls/well 30 bbls / day

Treated in the MSD** prior tmeet NPDES limits 

Is there a deck? If yes, there will be Deck Drainage

Deck Drainage Wash and rainwater 4,000 bbls/well 20 bbls / day Drained overboard through d

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. 

Chemical product waste Drilling additives added to well 50 bbls / well .5 bbls / day

Treated to meet NPDES limdischarged overboard 

Desalinization unit discharge Rejected water from watermaker unit 72,000 bbls/well 380 bbls /day Discharged overboard below 

Blowout prevent fluid Water based 400 bbls/well 50 bbls/day Disharge at seaBallast water Uncontaminated seawater 374,000 bbls/well 2,000 bbls / day Discharged overboard Just aBilge water

Bilge and drainage water will be treated to 

MARPOL standards (< 15ppm oil in water). 374,000 bbls/well 2,000 bbls / day

Bilge and drainage water w

MARPOL standards (< 15p

Excess cement at seafloor Cement slurry

1100 bbls/well (assume planned 100% excess is discharged) 1100 bbls / well

Discharged at the seafloor ddrilling 

Fire water Treated seawater 13,000 bbls/well 2,000 bbls / month Drained overboard through 

Cooling water Treated seawater 27,120,000 bbls/well 145,000 bbls / day

Discharged overboard 4

waterline 

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 GMG290103

NOTE: 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 DISCHAR

THE GOM

Projected generated waste Projected ocean discharge

Page 39 
B. Landfill, inject, incinerate or recycle table

Power Nap

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

Waste Oil Sludge

Waste Oil from MODU 

Machinery

N/A - Incinerated via onboard MODU 

Incinerator MODU Incinerator 12 m3/mont

Incinerate via onboard MODU that 

meets MARPOL 73/78, as 

amended, Annex VI, 

Regulation16(2), (a), / IMO 

Resolution MEPC. 76(40) amended 

by Resolution MEPC.93(45)

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

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.

Page 40 Public Information Copy
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

 *This plan includes fuel tracking reductions. 

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 Emission

Amounts 

(tons)

Calculated 

Exemption

Amounts 

(tons)

Calculated

Complex Total 

Emission 

Amounts

(tons)

PM

SOx

NOx

VOC

CO

2) Contact: Tracy Albert, 504.425.4652, tracy.albert@shell.com

(1) Worksheets

Worksheets included. Shell is providing the Excel worksheet on the Proprietary CD for your review. 

Page 41 Public Information Copy
Fuel Limit Basis for Drillships and DP Semi-subs

jbm - 6/24/13

Purpose

Step 1 - Determine Typical Operating Loads

Scenario 1 – Riser less drilling (top hole) - Four engines online @ 35 to 45%

Scenario 2 - Riser less drilling Running casing/ cementing - Four Engines online @ 30 to 40 %

Scenario 3 - Transit (5 knot log speed) - Four engines online @ 65% . Not considered further 

Scenario 4 – Drilling ahead with BOP deployed - Four Engines online @ 40 to 50% 

 

Op Mode 1 Op Mode 2 Op Mode 3 Op Mode 4

45% 40% 50%

45% 40% 50%

45% 40% 50%

45% 40% 50%

0% 0% 0%

0% 0% 0%

30% 27% 33%

Step 2 - Identify Corresponding Fuel Levels

Value

74615

33%

25,000

4.68

Step 3 - Other Vessel Fuel Loads

Value

50%

10,943

5,471

6,260

939

1.31

Additional Notes

Shell has reviewed engine information for its GOM fleet of Drillship and DP semi-sub MODUs. The single MODU with the largest 

power profile is the Noble Don Taylor, which has six main engines of 10,728 hp/engine. The projected fuel usages presented below 

would therefore be conservative across the fleet of Drillships and DP Semi-subs.

The Noble Don Taylor has six main engines. As confirmed by drillship owner, the below operating scenarios are considered 

representative for newbuild drilling rigs. Scenario 4 is selected as the conservative representation of typical engine loads. The 

highlighted cell indicates the highest power load scenario for this activity - Note Scenario 3 (transit) will be limited in duration and not 

considered representative for the full campaign. 

% Load

Engine

1

2

3

4

5

6

Average 

Description Notes

Proposed Operating Loads Shell policy restricts D/P to < 50% near rig. When in standby away from rig but 

within 25 miles load will be < 50% (conserve fuel). When transiting through field 

(25 nm), traveling at economical speeds. 

Description

PTE Fuel Use (gal/day) The Noble Don Taylor is equipped with 6 main engines at 10,728 hp each. The 

PTE fuel use is then estimated using the AQR conversion factor of 0.0483 gal/hphr.

Proposed Operating Load See Step 1 above.

Campaign Average Daily Fuel Use 

(gal/day)

Calculated Value - PTE fuel use * Proposed Operating Load and rounded up to 

nearest thousand (for additional conservatism).

Notes

CY2014-2017 Fuel Limits MMGals Calculated Value - Campaign Average Daily Fuel Use * Campaign Days 

Offshore Support Vessels

 PTE Fuel Use (gal/day) Offshore Support Vessels are rated at 9440 hp. The PTE fuel use is then 

estimated using the AQR conversion factor of 0.0483 gal/hp-hr.

Campaign Average Daily Fuel Use 

(gal/day)

Calculated Value - PTE fuel use * Proposed Operating Load. 

Crew Vessel

1 - Operating loads are campaign specific and may change in future AQRs depending on the future fuel usage tracking. Fuel levels 

depicted in this AQR does not restrict Shell from using a different value in future AQRs.

2 - If tracked fuel usage associated with this activity indicates emissions may exceed the approved emissions, Shell will submit 

revised AQR calculations.

PTE Fuel Use (gal/day) Crew Vessels are rated at 5400 hp. The PTE fuel use is then estimated using the 

AQR conversion factor of 0.0483 gal/hp-hr.

Campaign Average Daily Fuel Use 

(gal/day)

Calculated Value - PTE fuel use * Proposed Operating Load. Note that Crew Vessels 

are only in field 30% of campaign and daily average value has been adjusted 

Total Vessel Activity

CY2014-2017 Fuel Limits MMGals Sum of (vessel daily fuel use * corresponding campaign days)

Page 42 Public Information Copy
COMPANY Shell Offshore Inc.

AREA Mississippi Canyon

BLOCK 943

LEASE OCS-G 34467

PLATFORM Dynamically Positioned MODU

WELL A, B, C, D

COMPANY 

CONTACT Jeff McMenis

TELEPHONE NO. 504-425-6021

REMARKS SEPCO Env File Name - PowerNap_AQR_DPMODU_031114.xlsx

Page 43 Public Information Copy
Fuel Usage Conversion Factors Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine REF. DATE

SCF/hp-hr 9.524 SCF/hp-hr 7.143 GAL/hp-hr 0.0483 AP42 3.2-1 4/76 & 8/84

Equipment/Emission Factors units P M SOx NOx VOC CO REF. DATE

NG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3.2-1& 3.1-1 10/96

NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP42 3.2-1 10/96

NG 4-cycle lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP42 3.2-1 10/96

NG 4-cycle rich gms/hp-hr 0.00185 10 0.14 8.6 AP42 3.2-1 10/96

Diesel Recip. < 600 hp. gms/hp-hr 1 0.1835 14 1.12 3.03 AP42 3.3-1 10/96

Diesel Recip. > 600 hp. gms/hp-hr 0.32 0.1835 11 0.33 2.4 AP42 3.4-1 10/96

Diesel Boiler lbs/bbl 0.084 0.3025 0.84 0.008 0.21 AP42 1.3-12,14 9/98

NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 AP42 1.4-1, 14-2, & 14-3 7/98

NG Flares lbs/mmscf 0.593 71.4 60.3 388.5 AP42 11.5-1 9/91

Liquid Flaring lbs/bbl 0.42 6.83 2 0.01 0.21 AP42 1.3-1 & 1.3-3 9/98

Tank Vapors lbs/bbl 0.03 E&P Forum 1/93

Fugitives lbs/hr/comp. 0.0005 API Study 12/93

Glycol Dehydrator Vent lbs/mmscf 6.6 La. DEQ 1991

Gas Venting lbs/scf 0.0034

Sulphur 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

Per 40 CFR 80.510(a)(1), Locomotive and Marine (LM) diesel fuels are limited to 500 ppm 

maximum sulfur, effective June 1, 2007.

Page 44 Public Information Copy
Emissions for Incinerator (Waste Oil Incineration)

McMenis - 1/31/14 (updated 2/10/2014)

Table 1 - Emission Calculation Inputs

Value

0.083

0.022

144

6

264.1721

2000

Table 2 - Incinerator Emission Factors (lb/1000 gal)

PM SOx NOx VOC

64A 147S 19 1

Factors per AP 42 tables 1.11-1, 1.11-2 and 1.11-3, where A and S are provided below

1.00 A = ash percentage (assumed value to be consistent with other GOM incinerator calculations)

1.00 S = sulfur percentage (assumed value to be consistent with other GOM incinerator calculations)

Table 3 - CO Emission Factor

Value

200

36

984

264.1721

453592.4

59.126

Table 4 - Hourly and Annual Emissions

PM SOx NOx VOC CO PM SOx NOx VOC CO

Waste Oil Burning 1.409 3.236 0.418 0.022 1.302 0.632 1.452 0.188 0.010 0.584

Parameter Notes

Waste Oil Feed rate (m3/hr) provided via e-mail by Stena IceMax, Rig Manager based on 1 m3 feed rate every 12 hours 

Waste Oil Feed Rate (1000 gal/hr) Calculated Value, based on Feed Rate (m3/hr) and Conversion Factor (gal/m3)

Operations (hours/month) Calculated Value, based on an estimated 12 m3/calendar month and typical feed rate.

Months of Operation Consistent with Exploration Plan schedule (187 days)

Conversion Factor (gal/m3)

Conversion Factor (lb/ton)

Emission Factor Discussion - The BOEM's AQR emission spreadsheets do not provide emission factors for incinerators. In absence of this data, 

emission factors from USEPA AP-42 publication on Waste Oil Combustion (Chapter 1.11) have been utilized. It should be noted that the majority of 

default emission factors utilized by BOEM in the AQR spreadsheets have been provided by USEPA AP-42 publications. 

CO Emission Factor Note - The incinerator has Certificate of Shipboard Incinerator that identifies CO emission factor of 200 mg/MJ (converts to 59.13 

lb/1000 gal) in the flue gas, which is greater than the 5 lb/1000 gal emission factors provided by USEPA AP-42. In order to provide conservative 

emission estimates, the higher emission factor is utilized to estimate emissions. See Table 3 for detail on the Incinerator certificate and conversion 

formulas.

Parameter Notes

Certificate Emission Factor (mg/MJ) Page 3 of the Certificate of Shipboard Incinerator identifies the CO emission factor as 200 mg/MJ. 

This is consistent with Section A1.5 of ANNEX 8 - STANDARD SPECIFICATION FOR SHIPBOARD 

INCINERATORS, that identifies CO in flue gas maximum average as 200 mg/MJ. 

Waste Oil Heat Value (MJ/kg) Calorific Values are provided in Section A1.4 of ANNEX 8 - STANDARD SPECIFICATION FOR 

SHIPBOARD INCINERATORS. Oil Sludge is identified as 36,000 kJ/kg

Waste Oil Density (kg/m3) Calculated Value, based on design flow in 82 kg/hr (vendor certificate) and typical feed rates of 

0.083 m3/hr (see Table 1 for basis).

MAXIMUM POUNDS PER HOUR ESTIMATED TONS/CALENDAR YEAR

Conversion Factor (gal/m3)

Conversion Factor (mg/lb)

Certificate Emission Factor (lb/1000 gal) Calculated Value, Certificate Emission Factor (mg/MJ) * Waste Oil Heat Value (MJ/kg) * Waste 

Oil Density (kg/m3) / Conversion Factor (gal/m3) / Conversion Factor (mg/lb) * 1000 gal

Page 45 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc. Mississippi Canyon 943 OCS-G 34467 Dynamically Positioned MODU A, B, C, D Jeff McMenis 504-425-6021 SEPCO Env File Name - Pow erNap_AQR_DPMODU_031114-rev1.xlsx

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR ESTIMATED TONS

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 P M SOx NOx VOC CO P M SOx NOx VOC CO

MODU Drilling PRIME MOVER>600hp diesel 10728 518 24 184 7.56 4.34 259.93 7.80 56.71

DP Drillship or DP Semi PRIME MOVER>600hp diesel 10728 518 24 184 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 184 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 184 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 184 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 184 7.56 4.34 259.93 7.80 56.71

Energency Generator>600hp diesel 2547 123 1 184 1.80 1.03 61.71 1.85 13.46

Emergency Air Compressor< 600hp diesel 26 1 1 184 0.06 0.01 0.80 0.06 0.17

Incinerator 1.41 3.24 0.42 0.02 1.30 0.63 1.45 0.19 0.01 0.58

All other rig-equipment is electric (e.g cranes) or negligible in emissions potential (e.g. life boats, welding equipment, etc.)

Supply Vessel>600hp diesel (general support) 9440 456 5471 24 184 6.65 3.82 228.72 6.86 49.90 7.35 4.21 252.51 7.58 55.09

Supply Vessel>600hp diesel (riserless support) 9440 456 5471 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

Supply Vessel>600hp diesel (riserless support) 9440 456 5471 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

Crew Vessel>600hp diesel 5400 261 939 24 184 3.81 2.18 130.84 3.93 28.55 1.26 0.72 43.33 1.30 9.45

MISC. BPD SCF/HR COUNT

TANKDRILLING OIL BURN

WELL TEST GAS FLARE

2014 YEAR TOTAL 72.40 43.92 2439.51 73.23 533.47 43.60 26.09 1477.24 44.32 322.85

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 2164.50 2164.50 2164.50 2164.50 54965.20

65.0

NOTE: Emissions for Calendar-Years 2014-2017 account for reduced fuel usage. CY2018 activity accounts for only 4 days of operation and fuel reduction measures are not necessary to stay below the 

relevant BOEM exemption amounts. 

Emissions estimated on separate worksheet tab.

25000 33.56 19.25 1153.77 34.61 251.73

Page 46 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc. Mississippi Canyon 943 OCS-G 34467 Dynamically Positioned MODU A, B, C, D Jeff McMenis 504-425-6021 SEPCO Env File Name - Pow erNap_AQR_DPMODU_031114-rev1.xlsx

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR ESTIMATED TONS

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 P M SOx NOx VOC CO P M SOx NOx VOC CO

MODU Drilling PRIME MOVER>600hp diesel 10728 518 24 188 7.56 4.34 259.93 7.80 56.71

DP Drillship or DP Semi PRIME MOVER>600hp diesel 10728 518 24 188 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 188 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 188 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 188 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 188 7.56 4.34 259.93 7.80 56.71

Energency Generator>600hp diesel 2547 123 1 188 1.80 1.03 61.71 1.85 13.46

Emergency Air Compressor< 600hp diesel 26 1 1 188 0.06 0.01 0.80 0.06 0.17

Incinerator 1.41 3.24 0.42 0.02 1.30 0.63 1.45 0.19 0.01 0.58

All other rig-equipment is electric (e.g cranes) or negligible in emissions potential (e.g. life boats, welding equipment, etc.)

Supply Vessel>600hp diesel (general support) 9440 456 5471 24 188 6.65 3.82 228.72 6.86 49.90 7.51 4.30 258.00 7.74 56.29

Supply Vessel>600hp diesel (riserless support) 9440 456 5471 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

Supply Vessel>600hp diesel (riserless support) 9440 456 5471 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

Crew Vessel>600hp diesel 5400 261 939 24 188 3.81 2.18 130.84 3.93 28.55 1.29 0.74 44.28 1.33 9.66

MISC. BPD SCF/HR COUNT

TANKDRILLING OIL BURN

WELL TEST GAS FLARE

2015-2017 YEAR TOTAL 72.40 43.92 2439.51 73.23 533.47 44.52 26.62 1508.76 45.27 329.73

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 2164.50 2164.50 2164.50 2164.50 54965.20

65.0

Emissions estimated on separate worksheet tab.

NOTE: Emissions for Calendar-Years 2014-2017 account for reduced fuel usage. CY2018 activity accounts for only 4 days of operation and fuel reduction measures are not necessary to stay below the 

relevant BOEM exemption amounts. 

25000 34.29 19.67 1178.85 35.37 257.20

Page 47 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc. Mississippi Canyon 943 OCS-G 34467 Dynamically Positioned MODU A, B, C, D Jeff McMenis 504-425-6021 SEPCO Env File Name - Pow erNap_AQR_DPMODU_031114-rev1.xlsx

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR ESTIMATED TONS

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 P M SOx NOx VOC CO P M SOx NOx VOC CO

MODU Drilling PRIME MOVER>600hp diesel 10728 518 12436 24 4 7.56 4.34 259.93 7.80 56.71 0.36 0.21 12.48 0.37 2.72

DP Drillship or DP Semi PRIME MOVER>600hp diesel 10728 518 12436 24 4 7.56 4.34 259.93 7.80 56.71 0.36 0.21 12.48 0.37 2.72

PRIME MOVER>600hp diesel 10728 518 12436 24 4 7.56 4.34 259.93 7.80 56.71 0.36 0.21 12.48 0.37 2.72

PRIME MOVER>600hp diesel 10728 518 12436 24 4 7.56 4.34 259.93 7.80 56.71 0.36 0.21 12.48 0.37 2.72

PRIME MOVER>600hp diesel 10728 518 12436 24 4 7.56 4.34 259.93 7.80 56.71 0.36 0.21 12.48 0.37 2.72

PRIME MOVER>600hp diesel 10728 518 12436 24 4 7.56 4.34 259.93 7.80 56.71 0.36 0.21 12.48 0.37 2.72

Energency Generator>600hp diesel 2547 123 2952 1 4 1.80 1.03 61.71 1.85 13.46 0.00 0.00 0.12 0.00 0.03

Emergency Air Compressor< 600hp diesel 26 1 30 1 4 0.06 0.01 0.80 0.06 0.17 0.00 0.00 0.00 0.00 0.00

Incinerator 1.41 3.24 0.42 0.02 1.30 0.63 1.45 0.19 0.01 0.58

All other rig-equipment is electric (e.g cranes) or negligible in emissions potential (e.g. life boats, welding equipment, etc.)

Supply Vessel>600hp diesel (general support) 9440 456 10943 24 4 6.65 3.82 228.72 6.86 49.90 0.32 0.18 10.98 0.33 2.40

Supply Vessel>600hp diesel (riserless support) 9440 456 10943 24 0 6.65 3.82 228.72 6.86 49.90 0.00 0.00 0.00 0.00 0.00

Supply Vessel>600hp diesel (riserless support) 9440 456 10943 24 0 6.65 3.82 228.72 6.86 49.90 0.00 0.00 0.00 0.00 0.00

Crew Vessel>600hp diesel 5400 261 6260 24 4 3.81 2.18 130.84 3.93 28.55 0.18 0.10 6.28 0.19 1.37

MISC. BPD SCF/HR COUNT

TANKDRILLING OIL BURN

WELL TEST GAS FLARE

2018 YEAR TOTAL 72.40 43.92 2439.51 73.23 533.47 3.32 2.99 92.43 2.78 20.71

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 2164.50 2164.50 2164.50 2164.50 54965.20

65.0

Emissions estimated on separate worksheet tab.

NOTE: Emissions for Calendar-Years 2014-2017 account for reduced fuel usage. CY2018 activity accounts for only 4 days of operation and emission estimates were calculated at the potential to emit without 

consideration of fuel reduction measures.

Page 48 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore 

Inc.

Mississippi 

Canyon 943 OCS-G 34467 Dynamically Positioned MODU A, B, C, D

Emitted Substance

Year

PM SOx NOx VOC CO

2014 43.60 26.09 1477.24 44.32 322.85

2015-2017 44.52 26.62 1508.76 45.27 329.73

2018 3.32 2.99 92.43 2.78 20.71

Allowable 2164.50 2164.50 2164.50 2164.50 54965.20

Notes: 

1 - Emissions for Calendar-Years 2014, 2015, 2016, and 2017 account for reduced fuel usage. 

CY2018 activity accounts for only 4 days of operation and fuel reduction measures are not necessary to 

stay below the relevant BOEM exemption amounts. 

Page 49 Public Information Copy
SECTION 9: OIL SPILL INFORMATION

A. Oil Spill Response Planning

All the proposed activities and facilities in this EP will be covered by the Regional OSRP filed by Shell 

Offshore Inc. (0689) in accordance with 30 CFR 550 and 254. Shell’s Regional OSRP was approved by 

BSEE on April 11, 2013. 

Spill Response sites are as follows: 

Primary Response Equipment Locations Preplanned Staging Location(s) 

Venice, LA; Ft Jackson, LA; Harvey, LA; Stennis, 

MS; Pascagoula, MS

Venice, LA; Pacagouls, MS ; Mobile, AL

Table 9.1 – Response Equipment and Staging Areas 

The names of the OSRO’s under contract include Clean Gulf Associates (CGA), Marine Spill Response 

Company (MSRC), Clean Caribbean America (CCA) and OSRL/EARL. 

Category Regional OSRP EP

Type of Activity Subsea Drilling Exploratory Drilling

Facility Location (area/block) MC 391 MC 943

Facility Designation Subsea well 1◊ Subsea well A

Distance to Nearest Shoreline (miles) 70 65

Volume

Storage tanks (total)

Flowlines (on facility)

Pipelines

Uncontrolled blowout (volume per day)

Total Volume

N/A

N/A

N/A

416,414* BOPD

416,414 Bbls

N/A

N/A

N/A

 175,000** BOPD

175,000 Bbls

Type of Oil(s) - (crude oil, condensate, diesel) Crude oil Crude oil

API Gravity(s) 26o 28o

 *24 hour rate (391,808 BOPD 30 day average) 

**24 hour rate (165,000 BOPD 30 day average) 

◊This well was reviewed and accepted by BOEM in Plan S-7444 (May 2011) and corrected by BSEE on July 

10, 2012 during the drilling of the well. The 30-day average was updated in OSRP in July 2012. 

Since Shell Offshore Inc. has the capability to respond to the appropriate worst-case spill scenario included in 

its regional OSRP, approved by BSEE on April 11, 2013, and since the worst-case scenario determined for our 

Plan does not replace the appropriate worst-case scenario in our regional 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. 

Modeling:

Shell did not model a potential oil or hazardous substance spill for operations proposed in this plan. 

Page 50 Public Information Copy
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 BSEE Oil Spill Risk Analysis Model (OSRAM) for the Central and Western 

Gulf of Mexico available on the BSEE 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

MC 943 34467 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 943 WCD scenario. 

Page 51 Public Information Copy
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. Example 

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 943 Worst Case Discharge as effectively as 

possible. Below is a table outlining the applicable evaporation and surface dispersion quantity: 

Mississippi Canyon Block 943

Calculations

(BBLS)

i. TOTAL WCD (based on 30 day average (per day)) ~165,000

ii. Loss of volume of oil to natural surface dispersion and evaporation base 

(approximate bbls per day)*

(10% Natural surface evaporation and dispersion in 24 hrs)

-16,500

TOTAL REMAINING ~148,500

* As this scenario involves a surface blowout onboard the platform, an ADIOS 2 Model was ran to 

account for surface dispersion and evaporation. 

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 

Page 52 Public Information Copy
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 34 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 943 will be addressed in 

Shell’s NTL 2010-N10 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 529,000 

barrels/day. Temporary storage associated with the identified skimming and temporary storage 

equipment equals approximately 317,000 barrels. 

De-rated Recovery Rate

(bopd)

Storage

(bbls)

Offshore Recovery and 

Storage 295,339 305,285

Nearshore Recovery and 

Storage 233,856 12,516

Total 529,195 317,801

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 Activation 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. 

Page 53 Public Information Copy
 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 MWCC and Wild Well Control for a subsea dispersant 

packages. 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, these

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 

Page 54 Public Information Copy
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 05. 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. 

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Figure 9.C.1 Environmental Sensitivity Index Map Legend 

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Figure 9.C.2 South Pass ESI Map 

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Figure 9.C.3 Garden Island Pass ESI Map 

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. 

Figure 9.C.4 Pass a Loutre West ESI Map 

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Figure 9.C.5 Main Pass ESI Map 

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Table 9.D.4 Offshore On-Water Recovery and Storage Activation List 

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Table 9.D.4 Offshore On-Water Recovery and Storage Activation List (continued) 

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Table 9.D.4 Offshore On-Water Recovery and Storage Activation List (continued) 

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 Table 9.D.5 Nearshore On-Water Recovery Activation List 

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Table 9.D.5 Nearshore On-Water Recovery Activation List (continued) 

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Table 9.D.5 Nearshore On-Water Recovery Activation List (continued) 

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Table 9.D.5 Nearshore On-Water Recovery Activation List (continued) 

Table 9.D.6 Aerial Surveillance Activation List 

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Table 9.D.7 Offshore Aerial Dispersant Activation List 

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Table 9.D.7 Offshore Aerial Dispersant Activation List (continued) 

Table 9.D.8 Offshore Boat Spray Dispersant Activation List 

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Table 9.D.9 Control, Containment, and Subsea Dispersant Package Activation List 

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Table 9.D.10 In-Situ Burn Equipment Activation List 

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Table 9.D.10 In-Situ Burn Equipment Activation List (continued) 

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Table 9.D.10 In-Situ Burn Equipment Activation List (continued) 

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Table 9.D.10 In-Situ Burn Equipment Activation List (continued) 

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Table 9.D.10 In-Situ Burn Equipment Activation List (continued) 

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Table 9.D.11 Shoreline Protection and Wildlife Support List 

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Table 9.D.11 Shoreline Protection and Wildlife Support List (continued) 

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Table 9.D.11 Shoreline Protection and Wildlife Support List (continued) 

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Table 9.D.11 Shoreline Protection and Wildlife Support List (continued) 

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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. Shell will comply with NTL 2009-G02. 

B. Incidental Takes 

No incidental takes are anticipated. Although marine mammals may be seen in the area, Shell does not 

believe that its operations proposed under this EP will result Shell implements the mitigation measures and 

monitors for incidental takes of protected species according to the following notices to lessees and operators 

from the BOEM/BSEE: 

 NTL 2012-BSEE-G01 “Marine Trash and Debris Awareness and Elimination”

 NTL 2012-Joint-G01 “Vessel Strike Avoidance and Injured/Dead Protected Species Reporting”

 NTL 2012-Joint-G02 “Implementation of Seismic Survey Mitigation Measures & Protected Species 

Observer Program”

C. Flower Garden Banks National Marine Sanctuary 

The operations proposed in this plan will not be conducted within the Protective Zones of the Flower Garden 

Banks and Stetson Bank. 

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SECTION 11: LEASE STIPULATIONS INFORMATION

OCS-G 34467, MC 943, was part of Lease Sale #222 held on June 20, 2012. The lease has an expected expiration 

date of October 31, 2019. The lease is owned by Anadarko US Offshore Corporation (50%) and Shell Offshore Inc. 

(50%) and Shell is designated operator. The lease is not a part of any Biological Sensitive Area, Military Warning 

Area, high Archeological probability area, or Shipping Fairway. 

Lease Stipulation No. 8, Protected Species, is applicable to this lease and is addressed in the following sections of this 

plan: 

Section 6h, Threatened or endangered species, critical habitat, and marine mammal information 

Section 10b, Environmental Monitoring Information, Incidental takes 

Section 12b, Environmental Mitigation Measures Information, Incidental takes 

Section 18, Environmental Impact Assessment 

SECTION 12: ENVIRONMENTAL MITIGATION MEASURE INFORMATION

 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 OSRP. Section 18 of this plan discusses impacts and mitigation measures, including Coastal Habitats and 

Protected Areas. 

 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 BOEM/BSEE: 

NTL 2012-BSEE-G01 “Marine Trash and Debris Awareness and Elimination”

NTL 2012-Joint-G01 “Vessel Strike Avoidance and Injured/Dead Protected Species Reporting”

NTL 2012-Joint-G02 “NTL 2012-Joint-G02 “Implementation of Seismic Survey Mitigation Measures & 

Protected Species Observer Program”

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. 

 

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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 1 Twice per week

Offshore Support Vessels 120,000 2 Twice per week

Helicopter 760 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 943

C. Drilling Fluids Transportation 

According to NTL 2008-G04, this information in only required when activities are proposed in the State 

of Florida. 

D. Solid and Liquid Wastes Transportation 

See Section 7, Table 7B. 

E. Vicinity Map 

See Attachment 14A for Vicinity Map. 

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Attachment 14A – Vicinity Map

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SECTION 15: ONSHORE SUPPORT FACILITIES INFORMATION

A. General 

Name Location Existing/New/Modified

Boothville PHI Heliport Boothville, LA Existing

C-Port II Fourchon, LA Existing

The existing onshore support base for air transportation will be PHI Heliport in Boothville, LA located at 38963 

Highway 23. The existing onshore base for installation water traffic will be the C-Port II located at Port 

Fourchon Terminal located on Bayou LaFourche, south of Leeville, LA approximately three miles from the Gulf 

of Mexico. 

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 Table 7B. 

SECTION 16: SULPHUR OPERATIONS INFORMATION

Information regarding Sulfur Operations Information is not included in this EP as such information is only 

necessary in the case of DOCDs. 

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SECTION 17: COASTAL ZONE MANAGEMENT ACT (CZMA) INFORMATION

LOUISIANA

COASTAL ZONE MANAGEMENT 

CONSISTENCY CERTIFICATION 

INITIAL EXPLORATION PLAN 

Type of Plan 

 

MISSISSIPPI CANYON BLOCK 943

OCS-G 34467

 

The proposed activities described in detail in this Plan will comply with Louisiana's State and Local Coastal 

Resources Management Act of 1978, Coastal Resources Program, and Coastal Area Management Enforceable 

Policies. 

We have considered all of Louisiana's Enforceable Policies in making this certification of consistency. 

SHELL OFFSHORE INC. 

Operator 

_____________________________________________ 

Sylvia A. Bellone 

Certifying Official 

 03/18/2014

Date 

Page 85 Public Information Copy
MISSISSIPPI

COASTAL ZONE MANAGEMENT 

CONSISTENCY CERTIFICATION 

INITIAL EXPLORATION PLAN 

Type of Plan 

 

MISSISSIPPI CANYON BLOCK 943 

OCS-G 34467

The proposed activities described in detail in this Plan will comply with Mississippi’s approved Coastal Resources 

Program and Coastal Area Management Program Policies. 

We have considered all of Mississippi’s Enforceable Policies in making this certification of consistency.

SHELL OFFSHORE INC.

Operator 

_____________________________________________ 

Sylvia A. Bellone 

Certifying Official 

3/18/2014 

_____________________________________________ 

Date 

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Coastal Zone Management Consistency Information 

For the State of Mississippi 

Goal 1. To provide for reasonable industrial expansion in the Coastal Area and to insure the efficient utilization of 

waterfront industrial sites so that suitable sites are conserved for the water dependent industry. 

The proposed activities are located in OCS Federal Waters, Gulf of Mexico, approximately 65 miles from the 

nearest Louisiana shoreline. Shell will utilize existing facilities in Fourchon, Louisiana; therefore, there should not 

be any adverse impacts to the Mississippi coastal areas. 

Goal 2. To favor the preservation of the coastal wetlands and ecosystems, except where a specific alternation of 

specific coastal wetlands would serve a higher public interest in compliance with the public purposes of the public 

trust in which the coastal wetlands are held. 

The proposed activities are located in OCS Federal Waters, Gulf of Mexico, approximately 65 miles from the 

nearest Louisiana shoreline. Shell will utilize existing facilities in Fourchon, Louisiana; therefore, there should not 

be any adverse impacts to the Mississippi coastal areas. 

Goal 3. To protect, propagate, and conserve the State’s seafood and aquatic life in connection with the 

revitalization, and conserve the State’s seafood and aquatic life in connection with the revitalization of the 

seafloor industry of the State of Mississippi. 

The proposed activities are located in OCS Federal Waters, Gulf of Mexico, approximately 65 miles from the 

nearest Louisiana shoreline. Shell will utilize existing facilities in Fourchon, Louisiana; therefore, there should not 

be any adverse impacts to the Mississippi coastal areas. 

Goal 4. To conserve the air and waters of the State, and to protect, maintain and improve the quality thereof for 

public use, for the prorogation of wildlife, fish and aquatic life, and for domestic, agricultural, industrial, 

recreational and other legitimate beneficial uses. 

The proposed activities are located in OCS Federal Waters, Gulf of Mexico, approximately 65 miles from the 

nearest Louisiana shoreline. Shell will utilize existing facilities in Fourchon, Louisiana; therefore, there should not 

be any adverse impacts to the Mississippi coastal areas. 

 

Goal 5. To put the benefit use to the fullest extent of which they are capable to water resources of the State, 

and to prevent the waste, unreasonable use, or unreasonable method of use of water. 

The proposed activities are located in OCS Federal Waters, Gulf of Mexico, approximately 65 miles from the 

nearest Louisiana shoreline. Shell will utilize existing facilities in Fourchon, Louisiana; therefore, there should not 

be any adverse impacts to the Mississippi coastal areas. 

Goal 6. To preserve the State’s historical and archaeological resources, to prevent their destruction, and to 

enhance these resources whenever possible. 

The proposed activities are located in OCS Federal Waters, Gulf of Mexico, approximately 65 miles from the 

nearest Louisiana shoreline. Shell will utilize existing facilities in Fourchon, Louisiana; therefore, there should not 

be any adverse impacts to the Mississippi coastal areas. 

Goal 7. To encourage the preservation of natural scenic qualities in the coastal area. 

The proposed activities are located in OCS Federal Waters, Gulf of Mexico, approximately 65 miles from the 

nearest Louisiana shoreline. Shell will utilize existing facilities in Fourchon, Louisiana; therefore, there should not 

be any adverse impacts to the Mississippi coastal areas. 

Goal 8. To assist local government in the provision of public facilities services in a manner consistent with the 

coastal program. 

The proposed activities are located in OCS Federal Waters, Gulf of Mexico, approximately 65 miles from the 

nearest Louisiana shoreline. Shell will utilize existing facilities in Fourchon, Louisiana; therefore, there should not 

be any adverse impacts to the Mississippi coastal areas. 

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SECTION 18: ENVIRONMENTAL IMPACT ANALYSIS (EIA)

Environmental Impact Analysis 

INITIAL EXPLORATION PLAN 

Mississippi Canyon Block 943 (OCS-G 34467) 

Offshore Louisiana 

March 2014 

Prepared for:

Shell Offshore Inc. 

P.O. Box 61933 

New Orleans, Louisiana 70161 

Telephone: (504) 425-6021 

Prepared by:

CSA Ocean Sciences Inc. 

8502 SW Kansas Avenue 

Stuart, Florida 34997 

Telephone: (772) 219-3000 

Page 88 Public Information Copy
Acronyms and Abbreviations 

AUV autonomous underwater vehicle 

ADIOS Automated Data Inquiry for Oil Spills 

bbl barrel 

BOEM Bureau of Ocean Energy Management 

BOEMRE Bureau of Ocean Energy Management, 

Regulation and Enforcement 

BOP blowout preventer 

BOPD barrels of oil per day (bbl/d) 

BSEE Bureau of Safety and Environmental 

Enforcement 

C&C C&C Technologies, Inc. 

CH4 methane 

CO carbon monoxide 

CO2 carbon dioxide 

DP dynamically positioned 

DPS distinct population segment 

EFH Essential Fish Habitat 

EIA Environmental Impact Analysis 

EIS Environmental Impact Statement 

EP Exploration Plan 

ESA Endangered Species Act 

FAD fish-attracting device 

FR Federal Register 

GEMS Geoscience Earth and Marine Services, 

Inc. 

GMFMC Gulf of Mexico Fishery Management 

Council 

H2S hydrogen sulfide 

HAPC Habitat Area of Particular Concern 

IPF impact-producing factor 

MARPOL International Convention for the 

Prevention of Pollution from Ships 

MC Mississippi Canyon 

MMC Marine Mammal Commission 

MMPA Marine Mammal Protection Act 

MMS Minerals Management Service 

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 

NPDES National Pollutant Discharge Elimination 

System 

NRC National Research Council 

NTL Notice to Lessees and Operators 

NWR National Wildlife Refuge 

OCS Outer Continental Shelf 

OCSLA Outer Continental Shelf Lands Act 

OSAT Operational Science Advisory Team 

OSRA Oil Spill Risk Analysis 

OSRP Oil Spill Response Plan 

PAH polycyclic aromatic hydrocarbons 

PM particulate matter 

ROV remotely operated vehicle 

SBM synthetic-based mud 

SEA Site-Specific Environmental Assessment 

Shell Shell Offshore Inc. 

SOx sulfur oxides 

SWIM Surface Water Improvement and 

Management 

UME Unusual Mortality Event 

USCG U.S. Coast Guard 

USDOI U.S. Department of the Interior 

USEPA U.S. Environmental Protection Agency 

USFWS U.S. Fish and Wildlife Service 

VOC volatile organic compound 

WCD worst case discharge 

WMA Wildlife Management Area 

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INTRODUCTION 

Project Summary 

Shell Offshore Inc. (Shell) is submitting an Initial Exploration Plan (EP) for Mississippi Canyon 

Block 943 (MC 943) for four (4) exploration wells to be drilled using either a dynamically 

positioned (DP) drillship or DP semisubmersible drilling rig. This EP is for proposed well locations 

A, B, C, and D. All surface hole locations will be in MC 943, in the Central Planning Area of the 

Gulf of Mexico. 

The lease area is 65 miles (105 km) from the nearest shoreline (Louisiana), 106 miles (171 km) 

from the onshore support base at Port Fourchon, Louisiana, and 89 miles (143 km) from the 

helicopter base at Boothville, Louisiana. All miles in this Environmental Impact Analysis (EIA) are 

statute miles. Water depths at the wellsites range from approximately 4,211 to 4,276 ft 

(1,284 to 1,303 m). 

The following types of exploratory drilling rigs are available for this project: 

 Noble Don Taylor or a similar DP drillship; and 

 Noble Jim Day or a similar DP semisubmersible rig. 

The EIA is structured to address environmental impacts from both types of drilling rigs. 

Spudding for the proposed wells is scheduled for July 1, 2014, with an estimated timeline of 

187 days per well and one well drilled each year. 

Purpose of the EIA 

This EIA was prepared pursuant to the requirements of the Outer Continental Shelf Lands Act 

(OCSLA), 43 U.S.C. §§ 1331-1356, as well as regulations including 30 CFR 550.212(o) and 

550.227. The EIA is a project- and site-specific analysis of Shell’s planned activities under this 

EP1

. The EIA presents data, analyses, and conclusions to support BOEM 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). It also identifies 

some of the mitigation measures Shell will implement in connection with the planned activities. 

The 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 EP. The EIA also analyzes the potential environmental impacts of the 

revised blowout scenario and worst case discharge (WCD) information. 

BOEM 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 

 

1

 On October 1, 2011, the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) 

reorganized into two separate agencies: Bureau of Ocean Energy Management (BOEM) and Bureau of Safety and 

Environmental Enforcement (BSEE). Shell understands that BOEM will review this EIA and prepare a Site-Specific 

Environmental Assessment (SEA) for the project. This EIA complies with guidance provided in existing Notices to 

Lessees and Operators (NTLs) issued by the former Minerals Management Service (MMS) and BOEMRE, including 

NTL 2008-G04 (recently extended by NTL 2014-G03). Throughout this EIA, when existing guidance and general 

agency activities are referred to, “BOEM” is meant to subsume the former agencies and to represent the 

continuous regulatory entity now called BOEM. The former agency names (MMS and BOEMRE) are used when 

referring to particular historical documents published under those names. In addition, until NTLs are reissued 

under BOEM or BSEE, the EIA will refer to the former BOEMRE as BOEM when addressing NTLs issued by BOEMRE 

or MMS. 

Page 90 Public Information Copy
Programmatic Environmental Impact Statements (EISs) for the OCS Oil and Gas Leasing Program 

(MMS, 2007a; BOEM 2012a) and in lease sale EISs for the Western and Central Gulf of Mexico 

Planning Areas (MMS, 2007b; BOEM, 2012b,c, 2013). 

These studies generated critical data and advanced the large body of existing knowledge on the 

Gulf of Mexico OCS. They analyze potential impacts on the natural environment, the 

socioeconomic effects of exploration and development activities, and other regional resources. 

Numerous technical studies address the likely trajectory of spilled oil, the effects of underwater 

noise on threatened and endangered species, and other IPFs. The studies 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 BOEM and other regulatory agencies to 

evaluate Shell’s 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, where applicable. 

OCS Regulatory Framework 

The regulatory framework for OCS activities in the Gulf of Mexico was summarized in MMS (2010) 

and BOEM (2012b). 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, BOEM and BSEE are 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 

BSEE offshore regulations are in 30 CFR Chapter II, Subchapter B. BOEM offshore regulations 

are in 30 CFR Chapter V, Subchapter B. 

In implementing its responsibilities under the OCSLA and NEPA, the BOEM consults 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 BOEM and BSEE that provide clarification, description, 

or interpretation of a regulation or standard. Table 1 lists and summarizes the NTLs applicable 

to this EIA. 

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Table 1. Notices to Lessees and Operators (NTLs) that are applicable to this Environmental 

Impact Analysis (EIA). 

NTL Title Summary

2014-G03 Extension of Prior Notices to Lessees Extends the effective date of NTL 2008-G04 (and two other NTLs) until 

June 30, 2014.

BSEE2012-N06

Guidance to Owners and Operators of 

Offshore Facilities Seaward of the 

Coast Line Concerning Regional Oil 

Spill Response Plans

Provides clarification, guidance, and information for preparation of regional 

Oil Spill Response Plans. Recommends description of response strategy for 

WCD scenarios to ensure capability to respond to oil discharges is both 

efficient and effective.

2012-

JOINT-G01

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.

2012-

BSEE-G01

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.

2011-

JOINT-G01

Revisions to the List of OCS Blocks 

Requiring Archaeological Resource 

Surveys and Reports

Provides new information on which Outer Continental Shelf (OCS) blocks

require archaeological surveys and reports and line spacing required in each 

block. This NTL augments NTL 2005-G07.

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 Federal Register 

[FR] 63346). Informs operators that the BOEM 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 WCD scenario, and provides guidance regarding the 

information required in blowout scenario and WCD 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 OCS oil and gas activities in water depths greater 

than 984 ft (300 m). Prescribes separation distances of 2,000 ft (610 m) from 

each mud and cuttings discharge location and 250 ft (76 m) 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 984 ft (300 m) in the Gulf of Mexico.

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.

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.

Page 92 Public Information Copy
Oil Spill Prevention and Contingency Planning 

Shell’s Gulf of Mexico Regional Oil Spill Response Plan (OSRP) approved by BSEE is a 

fundamental component of the planned drilling program that certifies Shell’s capability to respond 

to the maximum extent practicable to a WCD (30 CFR 254.2) (see EP Section 9). 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 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 to a WCD from a well 

blowout. Shell’s program is intended to meet 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 550 for 

EPs. The main impact-related discussions are in Section A (Impact-Producing Factors) and 

Section C (Impact Analysis). 

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A. IMPACT-PRODUCING FACTORS 

Table 2 is a matrix of IPFs and potentially affected environmental resources adapted from 

Form BOEM-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: 

 Drilling rig 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 Drilling Rig Presence (including noise and lights) 

The wells will be drilled using a DP drillship or DP semisubmersible rig, which will be on site for 

an estimated 187 days per well. DP drillships and DP semisubmersible rigs are self-propelled and 

maintain position using a global positioning system, specific computer software, and sensors in 

conjunction with a series of thrusters. Offshore support vessels will be used during the drilling 

program, and there will likely be at least one vessel in the field at all times. Potential impacts to 

marine resources from the drilling rig include the physical presence of the DP vessel in the ocean, 

increased light from working and safety lighting on the vessel, and noise audible above and 

below the water surface. 

The physical presence of a DP drillship or DP semisubmersible rig in the ocean can attract pelagic 

fishes and other marine life, as discussed in Section C.5.1. Drilling vessels also maintain 

exterior lighting for working at night and navigational and aviation safety in accordance with 

federal regulations. Artificial lighting may attract and directly or indirectly impact natural 

resources, particularly birds, as discussed in Section C.4. 

Drilling operations produce noise that includes strong tonal components at low frequencies, 

including infrasonic frequencies in at least some cases (MMS, 2000). DP drillships and DP 

semisubmersible rigs can be expected to produce noise from both drilling and maintenance 

operations. Potential impacts of noise produced during drilling operations and vessel positioning 

are discussed in Section C.3 (threatened, endangered, and protected species) and Section C.4

(coastal and marine birds). 

Page 94 Public Information Copy
Table 2. Matrix of impact-producing factors and affected environmental resources. X = potential impact; dash (--) = no impact or 

negligible impact. 

Environmental Resources

Impact-producing Factors

Drilling Rig 

Presence (incl. 

noise & lights)

Physical 

Disturbance 

to Seafloor

Air 

Pollutant 

Emissions

Effluent 

Discharges

Water 

Intake

Onshore 

Waste 

Disposal

Marine 

Debris

Support 

Vessel/Helo 

Traffic

Accidents

Small Fuel 

Spill

Large Oil 

Spill

Physical/Chemical Environment

Air quality -- -- X -- -- -- -- -- X(6) X(6)

Water quality -- -- -- X -- -- -- -- X(6) X(6)

Seafloor Habitats and Biota

Soft bottom benthic communities -- X -- X -- -- -- -- -- X(6)

High-density deepwater benthic communities -- --(4) -- --(4) -- -- -- -- -- X(6)

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) -- -- -- -- -- -- X(8) X(6,8) X(6,8)

West Indian manatee (endangered) -- -- -- -- -- -- -- X(8) -- X(6,8)

Endangered mysticete whales -- -- -- -- -- -- -- -- -- --

Non-endangered marine mammals (protected) X -- -- -- -- -- -- X X(6) X(6)

Sea turtles (endangered/threatened) X(8) -- -- -- -- -- -- X(8) X(6,8) X(6,8)

Piping Plover (threatened) -- -- -- -- -- -- -- -- -- X(6)

Whooping Crane (endangered) -- -- -- -- -- -- -- -- -- X(6)

Gulf sturgeon (threatened) -- -- -- -- -- -- -- -- -- X(6)

Beach mice (endangered) -- -- -- -- -- -- -- -- -- X(6)

Coastal and Marine Birds

Marine and pelagic birds X -- -- -- -- -- -- X X(6) X(6)

Shorebirds and coastal nesting birds -- -- -- -- -- -- -- X -- X(6)

Fisheries Resources

Pelagic communities and ichthyoplankton X -- -- X X -- -- -- X(6) X(6)

Essential Fish Habitat X -- -- X X -- -- -- X(6) X(6)

Archaeological Resources

Shipwreck sites -- --(7) -- -- -- -- -- -- -- X(6)

Prehistoric archaeological sites -- --(7) -- -- -- -- -- -- -- X(6)

Coastal Habitats and Protected Areas

Beaches -- -- -- -- -- -- -- -- -- X(6)

Wetlands and seagrass beds -- -- -- -- -- -- -- X -- X(6)

Coastal wildlife refuges and wilderness areas -- -- -- -- -- -- -- -- -- X(6)

Socioeconomic and Other Resources

Recreational and commercial fishing X -- -- -- -- -- -- -- X(6) X(6)

Public health and safety -- -- -- -- -- -- -- -- X(6) X(6)

Employment and infrastructure -- -- -- -- -- -- -- -- X(6) X(6)

Recreation and tourism -- -- -- -- -- -- -- -- X(6) X(6)

Land use -- -- -- -- -- -- -- -- -- X(6)

Other marine uses -- -- -- -- -- -- -- -- -- X(6)

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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-mile zone of the Flower Garden Banks, or the 3-mile zone of Stetson Bank; 

(b) 1,000-m, 1-mile, or 3-mile 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 the given ranges (buffer zone) of any marine sanctuary, 

topographic feature, or no-activity zone. There are no submarine banks in the lease block. 

(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 and portions of Pensacola and Destin Dome area blocks in the 

Central Planning Area 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 BOEM as being in water depths 300 m or greater. 

 No impacts on high-density deepwater benthic communities are anticipated because no features 

indicative of high-density chemosynthetic communities or coral communities are located within 2,000 ft 

(610 m) of mud or cuttings discharge locations. 

(5) Exploration or production activities where hydrogen sulfide (H2S) concentrations greater than 500 ppm might 

be encountered. 

 EP Section 4 contains Shell’s request for classification as an area absent of H2S.

(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 BOEM 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. Although the lease area is on the list of 

archaeology survey blocks (BOEM, 2012d), the archaeological survey did not detect any potential 

submerged cultural resources within 2,000 ft (610 m) of the wellsites. The lease area is beyond the 60-m 

(197-ft) depth contour; therefore, prehistoric archaeological sites are not likely. A dynamically positioned 

drillship or semisubmersible rig will be used; therefore, no seafloor disturbances due to anchoring will 

occur. 

(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 or sea turtles include drilling rig 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. 

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Underwater marine sounds associated with drilling operations are not particularly intense and 

include strong tonal components at low frequencies (averaging 10 to 500 Hz) and infrasonic 

frequencies in at least some cases (Richardson et al., 1995; MMS, 2000). From a drillship or 

semisubmersible, sound and vibration associated with drilling operations are transmitted to the 

water either through the air or the risers (MMS, 2000). Marine sounds emitted by drilling rigs 

were found to be dominated by a mix of tones believed to be related to the drill string rotation 

rate. When drilling, the drill string represents a long vertical sound source (McCauley, 1998). 

The DP thrusters add another component to the marine sound signature from a drillship or 

semisubmersible drilling rig. DP thrusters can produce intermittent or continuous marine sound 

that varies depending on thruster type, operating efficiency, ship size, engine load, duty cycle, 

and weather or current conditions. 

The response of marine mammals, sea turtles, and fishes to a perceived marine sound depends 

on a range of factors, including 1) the sound pressure level, frequency, duration, and novelty of 

the sound; 2) the physical and behavioral state of the animal at the time of perception; and 

3) the ambient acoustic features of the environment (Hildebrand, 2004).

A.2 Physical Disturbance to the Seafloor 

The wells will be drilled with a DP drillship or DP semisubmersible rig, which do not use anchors. 

There will be minimal disturbance to the seafloor and soft bottom communities during positioning 

of the wellbore and blowout preventers. Physical disturbance of the seafloor will be limited to 

the proximal area where the wellbore penetrates the substrate and where mud and drill cuttings 

will be deposited. 

A.3 Air Pollutant Emissions 

Estimates of air pollutant emissions are provided in EP Section 8. Offshore air pollutant 

emissions will result from operations of thee drillships or DP semisubmersible rigs as well as 

service vessels and helicopters. These emissions occur mainly from combustion of diesel fuel. 

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). 

MC 943 is located westward of 87.5° W longitude; thus, air quality is under BOEM jurisdiction as 

explained in NTL 2009-N11. The BOEM implementing regulations are provided in 30 CFR 550 

Subpart C. The Air Quality Emissions Report (see EP Section 8) prepared in accordance with 

BOEM requirements shows that the projected emissions from emission sources associated with 

the proposed activities meet the BOEM exemption criteria and are therefore exempt from further 

air quality review pursuant to 30 CFR 550.303(d). Based on calculated emissions and the wells’ 

location relative to shore, it can be concluded that project emissions will not significantly affect 

onshore air quality for any of the criteria pollutants. No further analysis or control measures are 

required. 

A.4 Effluent Discharges 

Effluent discharges from the drillship vessel are summarized in EP Section 7. Discharges from 

the drilling vessel are required to be in compliance with and monitored as required by the 

National Pollutant Discharge Elimination System (NPDES) permit for oil and gas activities 

(GMG290000). Support vessel discharges are expected to 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. 

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Water-based drilling muds and cuttings will be released at the seafloor during the initial well 

intervals before the marine riser is set, which allows their return to the surface. Excess cement 

slurry will also 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 for drilling activities after the marine riser is 

installed that allows recirculation of the SBM fluids and cuttings. Unused or residual SBM will be 

collected and transported to Port Fourchon, Louisiana, for recycling. Drill cuttings will be 

discharged overboard via a downpipe below the water surface, after treatment that complies with 

the NPDES permit limits for synthetic fluid retained on cuttings. The estimated volume of drill 

cuttings to be discharged is provided in EP Section 7. 

Other effluent discharges from the drilling vessel and support vessel are expected to include 

excess cement, non-contact cooling water, treated sanitary and domestic wastes, deck drainage, 

desalination unit brine, uncontaminated fire water, and ballast water. Drilling vessel and support 

vessel discharges are expected to be in accordance with NPDES permit and USCG regulations, as 

applicable, and therefore are not expected to cause significant impacts on water quality. 

A.5 Water Intake 

Seawater will be drawn from several meters below the ocean surface for various services, 

including firewater and once-through non-contact cooling of machinery on the drilling vessel 

(EP Table 7a).

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 NPDES General Permit No. GMG290000 specifies requirements for new 

facilities for which construction commenced after July 17, 2006, with a cooling water intake 

structure having a design intake capacity of greater than 2 million gallons of water per day, of 

which at least 25% is used for cooling purposes. 

The wells will be drilled using either the Noble Don Taylor or a similar DP drillship, or the 

Noble Jim Day or a similar DP semisubmersible rig. If the drilling vessel selected for this project 

meets the described applicability for new facilities, the vessel’s water intakes are expected to be 

in compliance with the design, monitoring, and recordkeeping requirements of the NPDES permit. 

A.6 Onshore Waste Disposal 

Wastes generated during exploration activities are tabulated in EP Section 7. Non-hazardous 

trash and debris and non-recyclable waste will be transported to Republic/BFI landfill in Sorrento, 

Louisiana, or to the parish landfill in Avondale, Louisiana. Recyclable trash and debris will be 

recycled at Omega Waste Management in Patterson, Louisiana, or at ARC of New Iberia, 

Louisiana. Used oil will be sent to Omega Waste Management in Patterson, Louisiana, or to ARC 

of New Iberia, Louisiana. Hazardous waste will be sent to Safety Kleen in Denton, Texas. At the 

respective onshore facilities, wastes will be recycled or disposed of according to applicable 

regulations. 

A.7 Marine Debris 

Trash and debris released into the marine environment can harm marine animals 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 BSEE regulations and NTLs regarding solid wastes. BSEE regulations at 30 CFR 250.300(a) 

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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 

2012-BSEE-G01, 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 debris awareness 

training and certification process. Shell’s compliance with applicable laws, regulations, and NTL 

2012-BSEE-G01 will avoid significant impacts on the environment. 

A.8 Support Vessel and Helicopter Traffic 

Shell will use existing shore-based 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 is operated by Shell and located on Bayou Lafourche, 

approximately 3 miles (5 km) from the Gulf of Mexico. There will likely be at least one support 

vessel in the field at all times during drilling activities. The supply vessels will normally move to 

the project area via the most direct route from the shorebase. Helicopters transporting 

personnel and small supplies 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 700 ft (213 m) while in transit offshore; 1,000 ft (305 m) 

over unpopulated areas or across coastlines; and 2,000 ft (610 m) over populated areas and 

sensitive habitats such as wildlife refuges and park properties. Additional guidelines and 

regulations specify that helicopters maintain an altitude of 1,000 ft (305 m) within 300 ft (91 m) 

of marine mammals (BOEM, 2012a). 

Vessel noise is one of the main contributors to overall noise in the sea (National Research Council 

[NRC], 2003a; Jasny et al., 2005). Offshore supply and service vessels associated with the 

proposed project would contribute to the overall noise environment by transmitting noise through 

both air and water. Vessel noise is a combination of narrow-band (tonal) and broadband sound 

(Richardson et al., 1995). Tones typically dominate up to about 50 Hz, whereas broadband 

sounds may extend to 100 kHz. The primary sources of vessel noise are propeller cavitation, 

propeller singing, and propulsion; other sources include auxiliary engine noise, flow noise from 

water dragging along the hull, and bubbles breaking in the vessel’s wake while moving through 

the water (Richardson et al., 1995). Propeller cavitation is usually the dominant underwater 

noise source. The intensity of noise from service vessels is roughly related to ship size and 

speed. Broadband source levels for smaller boats (a category that would include supply and 

other service vessels) are in the range of 150 to 170 dB re 1 μPa at 1 m (Richardson et al., 

1995). 

Helicopters used for offshore oil and gas operation support are a potential source of noise to the 

marine environment. Helicopter noise is generated from their jet turbine engines, airframe, and 

rotors. The dominant tones for helicopters are generally below 500 Hz (Richardson et al., 1995). 

Richardson et al. (1995) reported received sound pressure levels in water of 109 dB re 1 μPa 

from a Bell 212 helicopter flying at an altitude of 152 m (500 ft). Penetration of aircraft noise 

below the sea surface is greatest directly below the aircraft; at angles greater than 13 degrees 

from vertical, much of the sound is reflected from the sea surface and so does not penetrate into 

the water (Richardson et al., 1995). The duration of underwater sound from passing aircraft is 

much shorter in water than air; for example, a helicopter passing at an altitude of 152 m (500 ft) 

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that is audible in air for 4 minutes may be detectable under water for only 38 seconds at 3 m 

(10 ft) depth and for 11 seconds at 18 m (59 ft) depth (Richardson et al., 1995). 

A.9 Accidents 

A.9.1 Types of Accidents Evaluated 

The analysis in this EIA focuses on two types of potential accidents: 

 a small fuel spill, which is the most likely type of spill during OCS exploration 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 detailed in 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. 

Lease sale EISs (MMS, 2007b; BOEM, 2012b,c) analyzed other types of accidents, including 

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 BOEM (2012b), the most likely type of small spill 

(<1,000 barrels [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 (BOEM, 2012b). 

The median size for spills <1 bbl is <0.024 bbl, and the median size for spills of 1 to 10 bbl is 

3 bbl (BOEM, 2012b). 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. 

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 and the short duration of a small spill, 

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 (NRC, 2003b). The constituents of these oils 

are light to intermediate in molecular weight and can be readily degraded by aerobic microbial 

oxidation. Diesel density is such that it will not sink to 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, 2003b) 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 Automated Data Inquiry for Oil 

Spills (ADIOS) 2 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 more than 90% of a small diesel spill 

would be evaporated or naturally dispersed within 24 hours. The area of diesel fuel on the sea 

surface would range from 1.2 to 12 ac (0.5 to 5 ha), depending on sea state and weather 

conditions. 

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The ADIOS 2 results, coupled with spill trajectory information discussed in the next section for a 

large spill, indicate that a small fuel spill would not affect coastal or shoreline resources. The 

lease area is 65 miles (105 km) from the nearest shoreline (Louisiana). Modeling results indicate 

that a surface spill in the lease area would have an 8% probability of contacting the nearest 

Louisiana shorelines within 30 days after a spill. Slicks from spills are expected to persist for 

relatively short periods of time ranging from minutes (<1 bbl) to hours (<10 bbl) to a few days 

(10 to 1,000 bbl) and rapidly spread out, evaporate and disperse into the water column 

(BOEM, 2012b). Because of the distance of these potential spills on the OCS and their lack of 

persistence, it is unlikely that a small diesel spill would make landfall prior to dissipation 

(BOEM, 2012b). 

Spill Response. In the unlikely event of a fuel spill, response equipment and trained personnel 

would be available to ensure that spill effects are localized and would result only in short-term, 

localized environmental consequences. 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 detailed in 

EP Section 2j. Blowouts are rare events and most do not result in oil spills (BOEM, 2012a). 

Spill Size. Shell has calculated a WCD for this EP using the requirements prescribed by 

NTL 2010-N06. The WCD is a 30-day average of 165,000 barrels of oil per day (BOPD). The 

detailed analysis of this calculation can be found in EP Section 2j. The WCD scenario for this 

EP has a low probability of being realized. Some of the factors that are likely to reduce rates and 

volumes, which 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. 

Shell has a robust system in place to prevent blowouts. Included in 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 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 (the launch area nearest to the lease area) are presented in 

Table 3. The model predicts no shoreline contact within 3 days. After 10 days, Plaquemines 

Parish, Terrebonne Parish, and Lafourche Parish in Louisiana may be contacted; after 30 days, 

8 other counties and parishes from Texas to Florida may be contacted. Plaquemines Parish, 

Louisiana, has the greatest probability of shoreline contact, with a 4% chance within 10 days and 

an 8% chance within 30 days. Other parishes and counties ranging from Texas to Florida have a 

3% or less probability of shoreline contact within 30 days. 

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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 OSRA Launch Area 58) could contact shoreline 

segments within 3, 10, or 30 days. 

Shoreline 

Segment County or Parish, State Conditional Probability of Contact1

(%)

3 Days 10 Days 30 Days

C10 Galveston, TX - - 1

C12 Jefferson, TX - - 1

C13 Cameron, LA - - 3

C14 Vermilion, LA - - 2

C15 Iberia, LA - - 1

C17 Terrebonne, LA - 1 3

C18 Lafourche, LA - 2 3

C19 Jefferson, LA - - 1

C20 Plaquemines, LA - 4 8

C21 St. Bernard, LA - - 1

C28 Okaloosa, FL - - 1

1 Conditional probability refers to the probability of contact within the stated time period, assuming that a spill has 

occurred (- indicates less than 0.5%). 

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 in 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 

BOEM to evaluate contact probabilities for spills greater than 1,000 bbl. 

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 PM, and stranding on shore or sedimentation to the 

seafloor (NRC, 2003b). 

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 for Permit to 

Drill 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, Marine Spill Response Corporation, Clean Gulf Associates, and Oil Spill 

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Response Limited, organizations that are committed to providing the resources necessary to 

respond to a spill as outlined in Shell’s OSRP.

Mechanical recovery capabilities are addressed in the OSRP. The mechanical recovery response 

equipment that could be mobilized to the spill location 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 identified in the OSRP. 

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 EP Section 9b for a detailed description of spill response measures. 

A.9.4 Other Accidents Not Analyzed in Detail 

The lease sale EISs (BOEM, 2012b,c, 2013) discuss four other types of accidents: chemical spills, 

pipeline failures, vessel collisions, and loss of well control. Three of these types of accidents 

considered relevant to this EP are briefly discussed in this section. Other than the presence of 

hydrogen sulfide (H2S), which is addressed below, no other site-specific issues have been 

identified for this EP. The analysis in the lease sale EISs for these topics is incorporated by 

reference. 

Chemical Spill. Chemicals are used in drilling and producing operations to achieve technical goals 

in the drilling process, improve the efficiency and safety of drilling, and protect associated 

equipment. Chemicals used during 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 rig: 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 in the concentrations typically 

used: zinc bromide and ammonium chloride (Boehm et al., 2001). The project addressed by this 

EP does not anticipate the use of either zinc bromide or ammonium chloride. Most other 

chemicals are either nontoxic or used in small quantities (BOEM, 2012b,c, 2013). No significant 

impacts are expected from chemical spills. 

Vessel Collisions. As summarized in MMS (2007b) and BOEM (2012b,c, 2013), 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. About 10% of these 

collisions have caused spills of diesel fuel or chemicals (BOEM, 2012b,c). Shell will comply with 

USCG and BOEM-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, discussed in 

Section A.9.3, are considered to be a more serious subset of loss of well control incidents with 

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greater risk of oil spill or human injury (MMS, 2007b). Not all loss of well control events result in 

blowouts (BOEM, 2012b,c, 2013). In addition to the potential release of gas, condensate, oil, 

sand, or water, the loss of well control can also resuspend and disperse bottom sediments 

(BOEM, 2012b). BOEM (2012b,c, 2013) noted that most OCS blowouts have resulted in the 

release of gas. 

Shell has a robust system in place to prevent loss of well control. Included in this 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 Final Drilling Safety Rule, which 

specify additional safety measures for OCS activities. See EP Sections 2j and 9b for further 

information. 

H2S Release. EP Section 4 contains Shell’s request for classification as an area absent of H2S.

B. AFFECTED ENVIRONMENT 

The lease area is in the central Gulf of Mexico, 65 miles (105 km) from the nearest shoreline, 

106 miles (171 km) from the onshore support base at Port Fourchon, Louisiana, and 89 miles 

(143 km) from the helicopter base at Boothville, Louisiana. 

Water depths at the proposed wellsites range from approximately 4,211 to 4,276 ft 

(1,284 to 1,303 m). The proposed wellsites range from 825 to 1,750 ft (91 to 209 m) from the 

nearest seafloor faults and 300 to 700 ft (91 to 213 m) from the nearest buried amplitudes 

(Geoscience Earth and Marine Services, Inc. [GEMS], 2013). No fault or amplitude penetration is 

expected at any of the proposed wellsites. 

The geologic, stratigraphic, and archaeological assessment detected marine avoidance targets 

within 2,000 ft (610 m) of the proposed wellsites (C&C Technologies, Inc. [C&C], 2007; 

GEMS, 2013). Each of these targets will be avoided by 100 ft (31 m) or more. Each target will 

be assigned an Avoidance Zone Number, and exact geographic coordinates of the targets will be 

plotted to allow the drilling subcontractor to avoid them. There are no existing wells, flowlines, 

or umbilicals in the vicinity of any of the proposed wellsites (C&C , 2007; GEMS, 2013). 

The archaeological assessment confirmed the existence of modern debris primarily associated 

with prior industrial waste disposal or field development activities. A discontinued industrial 

waste disposal site is located northwest of the lease area. Shell’s procedure “Waste Barrel 

Avoidance and Release Response in the Mississippi Canyon Area,” which was approved by 

MMS and BOEM2

, applies to operations that could cause a disturbance of a seafloor barrel. 

Shell’s overarching policy is to avoid barrel contact. 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. 

A detailed description of the regional affected environment is provided in MMS (2007b) and 

BOEM (2012b,c), including meteorology, oceanography, geology, air and water quality, benthic 

 

2

 MMS approval of West Boreas Supplemental Exploration Plan, MS 5231 December 16, 2008, Control No. S-07273, 

Mississippi Canyon Area Block 762, Lease OCS-G 07957; Mississippi Canyon Area Block 806, Lease OCS-G 07962 

and BOEM approval of the Supplement to the Conceptual Deepwater Operations Plan for Mars B project, 

August 12, 2010, MS 5220. 

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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 in the following sections, and brief descriptions of each potentially 

affected resource are presented in Section C, including site-specific and/or new information if 

available. 

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 MMS (2007b) and BOEM (2012b,c). 

C. IMPACT ANALYSIS 

This section analyzes 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 lease sale EISs for the Western and Central Gulf of 

Mexico Planning Areas (MMS, 2007b; BOEM, 2012b,c, 2013). Site-specific issues are addressed 

in this section as appropriate. 

C.1 Physical/Chemical Environment 

C.1.1 Air Quality 

Due to the distance from shore-based 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). 

In general, ambient air quality on coastal counties along the Gulf of Mexico is relatively good 

(BOEM, 2012a). As of December 5, 2013, Louisiana, Mississippi, Alabama, and Florida coastal 

counties and parishes are in attainment of the National Ambient Air Quality Standards (NAAQS) 

for all criteria pollutants (USEPA, 2013). One coastal metropolitan area in Texas 

(Houston-Galveston-Brazoria) is a nonattainment area for 8-hour ozone. One coastal 

metropolitan area in Florida (Tampa) is a nonattainment area for lead based on the 

2008 Standard. 

Winds in the region are driven by the clockwise circulation around the Bermuda High 

(BOEM, 2012b). 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 that could potentially affect 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 as well as helicopters and service 

vessels as described in Section A.3. These emissions occur mainly from combustion or burning 

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of diesel fuel. 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 impact 

air quality along the coast. As noted in the lease sale EISs (MMS, 2007b; BOEM, 2012b,c, 2013), 

emissions of air pollutants from routine activities in the Gulf of Mexico Central Planning Area are 

projected to have minimal impacts on onshore air quality because of the prevailing atmospheric 

conditions, emission heights, emission rates, and the distance of these emissions from the 

coastline. 

MC 943 is located westward of 87.5° W longitude; thus, air quality is under BOEM jurisdiction as 

explained in NTL 2009-N11. The BOEM implementing regulations are provided in 30 CFR 550 

Subpart C. The Air Quality Emissions Report (see EP Section 8) prepared in accordance with 

BOEM requirements shows that the projected emissions from emission sources associated with 

the proposed activities meet the BOEM exemption criteria. This EP is therefore exempt from 

further air quality review pursuant to 30 CFR 550.303(d). 

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 Class I air quality 

area. The BOEM coordinates with the USFWS if emissions from proposed projects may affect the 

Breton Class I area. The lease area is approximately 99 miles (160 km) from the Breton 

Wilderness Area. Shell will comply with emissions requirements as directed by the BOEM. 

Carbon dioxide (CO2) and methane (CH4) emissions from the project would constitute a negligible 

contribution to greenhouse gas emissions from all OCS activities. According to Programmatic and 

OCS lease sale EISs (BOEM, 2012a,b), estimated CO2 emissions from OCS oil and gas sources are 

0.4% of the U.S. total. OCS activities in the Central and Western Planning Areas contribute 

approximately 0.005% to total global CO2 emissions (BOEM 2012b). Greenhouse gas emissions 

from this proposed project 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 Programmatic EIS 

(BOEM, 2012a). 

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 MMS (2007b) and BOEM (2012b,c, 2013). 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. EP Section 9b provides 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 likely affect air quality near the spill site by introducing VOCs through 

evaporation. The ADIOS 2 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 diesel fuel on the sea 

surface would range from 1.2 to 12 ac (0.5 to 5 ha), 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 MMS (2007b) and BOEM (2012b,c, 2013). 

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A large oil spill would likely 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 approved by the Unified 

Command included in situ burning of the floating oil. In situ burning would generate a plume of 

black smoke offshore and result in emissions of NOx, SOx, CO, and PM, as well as greenhouse 

gases. 

Due to the lease area location (65 miles [105 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, Terrebonne Parish, and Lafourche Parish, 

Louisiana, are the coastal areas 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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on air quality are expected. 

C.1.2 Water Quality 

Deepwater areas in the Gulf of Mexico are relatively homogeneous with respect to temperature, 

salinity, and oxygen (MMS, 2007b). IPFs that could potentially affect water quality are effluent 

discharges and two types of accidents – a small fuel spill and a large oil spill. 

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. NPDES permit limits 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). Recent EISs have concluded that the discharge of 

treated SBM cuttings will not cause persistent impacts on water quality in the lease area 

(BOEM 2012b,c, 2013). 

Treated sanitary and domestic wastes may have a slight transient effect on water quality in the 

immediate vicinity of these discharges. NPDES permit limits and requirements will be met, and 

little or no impact on water quality is anticipated. 

Deck drainage includes 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 will flow overboard without treatment. However, rainwater that falls on 

the drilling rig 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. 

Negligible impact on water quality is anticipated. 

Other discharges from the proposed drilling rig will be in accordance with the NPDES permit. 

Discharges include desalination unit brine and uncontaminated cooling water, fire water, and 

ballast water and 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. Support vessel discharges are 

subject to USCG regulations and therefore are not expected to cause significant impacts on water 

quality. 

Page 107 Public Information Copy
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 MMS (2007b) and BOEM (2012b,c, 2013). 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. EP Section 9b provides 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 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 diesel fuel on the sea 

surface would range from 1.2 to 12 ac (0.5 to 5 ha), depending on sea state and weather 

conditions. 

The water-soluble fractions of diesel are dominated by two- and three-ringed PAHs, which are 

moderately volatile (NRC, 2003b). 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, 2003b) 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 MMS (2007b) and BOEM (2012b,c, 2013). A large spill would likely 

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 observations following the Macondo spill indicate 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). Recent analyses of the full set of 

samples associated with the Macondo spill have confirmed that the application of subsurface 

dispersants resulted in subsurface hydrocarbon plumes (Spier et al., 2013). A report by 

Kujawinski et al. (2011) indicates that chemical components of subsea dispersants used during 

the Macondo spill persisted for up to 2 months and were detectable up to 186 miles (300 km) 

from the wellsite at a water depth of 3,280 to 3,937 ft (1,000 to 1,200 m). While dispersants 

were detectable in 353 of the 4,114 total water samples, concentrations in the samples were 

significantly below the chronic screening level for dispersants (BOEM, 2012c). 

Once oil enters the ocean, a variety of physical, chemical, and biological processes act 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, 

2003b). 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. 

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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 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 slight depression of dissolved oxygen concentrations relative to climatological 

background values, the findings were not indicative of hypoxia (<2.0 mg/L) (Operational Science 

Advisory Team [OSAT], 2010). Stations revisited around the Macondo wellhead in October 2010 

showed no measurable oxygen depressions (OSAT, 2010). 

Due to the lease area location, 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 modeling predictions (Table 3), nearshore waters 

and embayments of Plaquemines Parish, Terrebonne Parish, and Lafourche Parish, Louisiana, are 

the coastal areas 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 detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on water quality are expected. 

C.2 Seafloor Habitats and Biota 

Water depths at the proposed well surface locations range from approximately 4,211 to 4,276 ft 

(1,284 to 1,303 m). See EP Section 6a for further information. 

According to BOEM (2012b,c, 2013), existing information for the deepwater Gulf of Mexico 

indicates that the seafloor is composed primarily of soft sediments; hard bottom communities are 

rare. In accordance with the guidance of NTL 2008-G04, a remotely operated vehicle (ROV) 

Monitoring Survey Plan is one of several requirements to accompany the EP when there is a 

potential to disturb seafloor areas in deepwater (>400 m). The specific requirements of the ROV 

Survey Plan are detailed in NTL 2008-G06. The BOEM (2011) has subdivided the Gulf of Mexico 

Region (Western Planning Area, Central Planning Area, and parts of Eastern Planning Area) into 

grids. MC 943 is within deepwater Grid 13 where remotely operated vehicle coverage of the 

seafloor is considered adequate to characterize the area (BOEM, 2011), and as such an ROV 

Monitoring Survey Plan is not necessary to accompany the EP. An autonomous underwater 

vehicle (AUV) survey consisting of side-scan sonar, multibeam bathymetry, and subbottom 

profiler data collection was conducted (GEMS, 2013). 

C.2.1 Soft Bottom Benthic Communities 

Data from the 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 to the 

proposed MC 943 wells (approximately 1,294 m water depth). Sediments at these two stations 

were similar, predominantly clay (45.5% at MT4 and 52.6% at MT3) and silt (45.5% at MT4 and 

41.5% at MT3) (Rowe and Kennicutt, 2009). 

Table 4. Benthic community data from stations nearest to the lease area 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). 

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Station

Location 

Relative to 

Lease Area

Water Depth

(m)

Abundance

Meiofauna

(individuals/m2)

Macroinfauna

(individuals/m2)

Megafauna

(individuals/ha)

MT4 17 miles SSW 1,401 246,058 3,262 1,548

MT3 32 miles WNW 990 885,995 4,924 1,034

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 890,000 

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. 

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 depth of the wellsites are expected to be about 

2,600 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. Zone 2E consists of stations ranging in depth from 2,831 to 5,315 ft 

(625 to 1,828 m), covering mid Texas-Louisiana Slope, the west flank of the Mississippi Fan, the 

mid Mississippi Canyon, the head of De Soto Canyon, and the mid West Florida Terrace. The five 

most abundant species in Zone 2E were the polychaetes Aricidea suecica, Exogone sp. A., 

Paralacydonia paradoxa, and Tharyx annulosus (Wei, 2006). 

Megafaunal density from nearby station MT4 was 1,548 individuals/ha (Table 4). Densities of 

195 to 2,941 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 the foundation of deep-sea chemosynthetic communities (Ross et al., 2012) and are 

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 1.5 grams of carbon 

per square meter (g C m−

2

) in the top 6 in. (15 cm) of sediments (Rowe and Kennicutt, 2009). 

IPFs that could potentially affect benthic communities are physical disturbance, effluent 

discharges (drilling mud 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 Physical Disturbance to the Seafloor 

In water depths such as those that are encountered in the lease area, DP drillships or 

DP semisubmersible rigs disturb the seafloor only around the wellbore (surface hole location) 

where the bottom template and blowout preventer are located. Depending upon the specific well 

configuration, this area is generally about 0.62 ac (0.25 ha) (BOEM, 2012b). 

The areal extent of these impacts from the drilling rig will be small compared to the lease area 

itself. Soft bottom communities are ubiquitous along the northern Gulf of Mexico continental 

slope (Gallaway et al., 2003; Rowe and Kennicutt, 2009). Physical disturbance to the seafloor 

during this project will have no significant impact on soft bottom benthic communities on a 

regional basis. 

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Impacts of Effluent Discharges 

Drilling mud and cuttings are the only effluents 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 mud 

(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 mud, 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 SBM 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 

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; the typical effect radius is 

1,640 ft (500 m) around each wellsite. For the four surface locations in this exploration drilling 

program, the total impact area would be 776 ac (314 ha). In light of the proximity of the 

proposed wells to each other, the overall impact area could be reduced. 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. 

Impacts of a Large Oil Spill 

Potential impacts of a large oil spill on the benthic community are expected to be consistent with 

those analyzed and discussed in MMS (2007b) and BOEM (2012b,c, 2013). Likely impacts from a 

subsea blowout include smothering and exposure to toxic hydrocarbons from oiled sediment 

settling to the seafloor. 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 984-ft (300-m) 

radius. While coarse sediments (sands) would probably settle at a rapid rate within 1,312 ft 

(400 m) from the blowout site, fine sediments (silts and clays) could be resuspended for more 

than 30 days and dispersed over a much wider area. A previous study characterized surface 

sediments in the vicinity of the site as about 53% clay and 42% 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 

3,600 ft (1,100 m), 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 

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dispersants at the wellhead (Joint Analysis Group, 2010c; Spier et al., 2013). Chemical 

components of subsea dispersants used during the Macondo spill persisted for up to 2 months 

and were detected up to 186 miles (300 km) from the wellsite at a water depth of 3,280 to 

3,937 ft (1,000 to 1,200 m) (Kujawinski et al., 2011). 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 984-ft (300-m) radius estimated 

in MMS (2007a, 2008), depending on its extent, trajectory, and persistence (Spier et al., 2013). 

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, 2003b). 

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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides 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 in NTL 2009-G40, high-density deepwater benthic communities are features or areas 

that could support high-density chemosynthetic communities, high-density deepwater corals, or 

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; Brooks et al., 

2012). These communities occur almost exclusively on authigenic carbonates created by 

chemosynthetic communities, and on shipwrecks. 

Monitoring programs on the Gulf of Mexico continental slope have shown that benthic impacts 

from drilling discharges typically are concentrated within about 1,640 ft (500 m) of the wellsites, 

although detectable deposits may extend beyond this distance (Continental Shelf Associates, Inc., 

2004, 2006; Neff et al., 2005). The nearest known high-density deepwater benthic community 

site is located approximately 54 miles (88 km) west of the lease area in MC 969 (Brooks et al., 

2009). The site clearance survey by GEMS (2013) did not identify any features that could 

support high-density deepwater benthic communities within 2,000 ft (610 m) of the proposed 

drilling mud/cuttings discharge locations. 

The only IPF identified for this project that could potentially affect high-density deepwater 

benthic communities is 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. 

Impacts of a Large Oil Spill 

BOEM (2012a) 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 3,600 ft (1,100 m), 

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). Chemical components of subsea dispersants used 

during the Macondo spill persisted for up to 2 months and were detectable up to 186 miles 

(300 km) from the wellsite at a water depth of 3,280 to 3,937 ft (1,000 to 1,200 m) (Kujawinski 

et al., 2011). 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 

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not well known, a subsurface plume could have the potential to contact high-density deepwater 

benthic communities beyond the 984-ft (300-m) radius estimated in BOEM (2012a), depending 

on its extent, trajectory, and persistence. Oil plumes that contact sensitive benthic communities 

before degrading could potentially impact the resource (BOEM, 2012b). Potential impacts on 

sensitive resources would be an integral part of the decision and approval process for the use of 

dispersants. The site clearance assessment by GEMS (2013) did not identify high-density 

deepwater benthic communities within 2,000 ft (610 m) of the proposed drilling mud/cuttings 

discharge locations. Potential impacts of oil on high-density deepwater benthic communities are 

discussed in MMS (2007b) and BOEM (2012b). 

Although chemosynthetic communities live among hydrocarbon seeps, natural seepage occurs at 

a relatively constant low rate compared with the potential rates of oil release from a blowout. In 

addition, seep organisms 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 in 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) (BOEM, 2012c). 

The potential for a spill to affect deepwater corals was observed during an October 2010 survey 

of deepwater coral habitats in water depths of 4,600 ft (1,400 m) approximately 7 miles (11 km) 

southwest of the Macondo wellhead. Much of the soft coral observed in a location measuring 

about 50 by 130 ft (15 by 40 m) was covered by a brown flocculent material (BOEMRE, 2010) 

with signs of stress, including varying degrees of tissue loss and excess mucous production 

(White et al., 2012a,b). Researchers concluded, based on hopanoid petroleum biomarker 

analysis of the flocculent material, that it contained oil from the Macondo spill. The injured and 

dead corals were in an area where a subsea plume of oil had been documented during the spill in 

June 2010. The deepwater coral at this location showed signs of tissue damage that was not 

observed elsewhere during these surveys or in previous deepwater coral studies in the Gulf of 

Mexico. The team of researchers concluded that the observed coral injuries likely resulted from 

exposure to the subsurface oil plume (White et al., 2012a,b). 

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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Potential 

impacts on sensitive resources would be an integral part of the decision and approval process for 

the use of dispersants. Therefore, no significant spill impacts on deepwater benthic communities 

are expected. 

C.2.3 Designated Topographic Features 

The block is not within or near a designated topographic feature or a no-activity zone as 

identified in NTL 2009-G39. The nearest designated topographic feature stipulation block is 

Sackett Bank in West Delta Block 147, located 52 miles (83 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. 

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C.2.4 Pinnacle Trend Area Live Bottoms 

The lease area is not covered by the Live Bottom (Pinnacle Trend) Stipulation. As defined in 

NTL 2009-G39, the nearest pinnacle trend blocks are located about 91 miles (146 km) 

north-northeast of the lease area in Main Pass Block 290. 

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. 

C.2.5 Eastern Gulf Live Bottoms 

The lease area is not covered by the Live Bottom (Low-Relief) Stipulation, which pertains to 

seagrass communities and low-relief hard-bottom reef within the Gulf of Mexico Eastern Planning 

Area blocks in water depths of 328 ft (100 m) or less and portions of Pensacola and Destin Dome 

Area Blocks in the Central Planning Area. The nearest blocks covered by the live bottom 

stipulation, as defined in NTL 2009-G39, are about 121 miles (195 km) northeast of the project 

area. 

There are no IPFs associated with either routine operations or accidents that could cause impacts 

to eastern Gulf of Mexico live bottom areas due to the distance from the lease area. 

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 that are protected under the MMPA. 

Endangered, threatened, or species of concern that may occur in the project area and/or along 

the northern and eastern Gulf Coast are listed in Table 5. The table also indicates the location 

of designated critical habitat 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 and fishes in the Gulf of Mexico. The 

USFWS has jurisdiction over ESA-listed birds and the West Indian manatee. These two agencies 

share federal jurisdiction over sea turtles, with NMFS having lead responsibility at sea and USFWS 

on nesting beaches. 

Table 5. Listed endangered and threatened species in the lease area and along the northern and 

eastern Gulf Coast. 

Species Scientific Name Status

Potential Presence Critical Habitat 

Designated in

Gulf of Mexico

Lease 

Area Coastal

Marine Mammals

Sei whale Balaenoptera borealis E X

a

-- None

Blue whale Balaenoptera musculus E X

a

-- None

Fin whale Balaenoptera physalus E X

a

-- None

North Atlantic right whale Eubalaena glacialis E X

a

-- None

Humpback whale Megaptera novaeangliae E X

a

-- None

Sperm whale Physeter macrocephalus E X -- None

West Indian manatee Trichechus manatus latirostris E -- X Florida (Peninsular)

Sea Turtles

Loggerhead turtle Caretta caretta T, Eb X X Proposedb

Green turtle Chelonia mydas T, Ec X X None

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Table 5. (Continued). 

Species Scientific Name Status

Potential Presence Critical Habitat 

Designated in

Gulf of Mexico

Lease 

Area Coastal

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 composed of nine distinct population segments (DPS) that are considered “species.” The 

only DPS that may occur in the project area (Northwest Atlantic DPS) is listed as threatened (76 Federal Register 

[FR] 58868; September 22, 2011). The National Marine Fisheries Service and U.S. Fish and Wildlife Service have 

proposed to designate critical habitat for this DPS, including beaches in Jackson County, Mississippi; Baldwin 

County, Alabama; and Bay, Gulf, and Franklin Counties in the Florida panhandle, as well as several counties in 

southwest Florida and the Florida Keys (78 FR 18000). 

c The green sea turtle is threatened except for the Florida breeding population, which is listed as endangered. 

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) have also 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 West Indian 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 in MMS (2007b) and 

BOEM (2012b) are no longer federally listed as endangered or threatened; these species are 

discussed in Section C.4.2, Shorebirds and Coastal Nesting 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 

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(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 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., 2013). 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 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 656- and 3,280-ft (200- and 

1,000-m) depth contours (Jochens et al., 2008). Male sperm whales were more variable in their 

movements and were documented in water depths greater than 9,843 ft (3,000 m). Generally, 

groups of sperm whales sighted in the Gulf of Mexico during the MMS-funded Sperm Whale 

Seismic Study 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). A review of sighting reports from seismic mitigation surveys in the Gulf of Mexico 

conducted over a 6-year period found a mean group size for sperm whales of 2.5 individuals 

(Barkaszi et al., 2012). 

In these mitigation surveys, sperm whales were the most common cetacean encountered 

(Barkaszi et al., 2012). Results of the Sperm Whale Seismic Study showed 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). 

Current threats to sperm whale populations worldwide are discussed in a final recovery plan for 

the sperm whale published by NOAA (NMFS, 2010a). Threats are defined as “any factor that 

could represent an impediment to recovery,” and include fisheries interactions, anthropogenic 

noise, vessel interactions, contaminants and pollutants, disease, injury from marine debris, 

research, predation and natural mortality, direct harvest, competition for resources, loss of prey 

base due to climate change and ecosystem change, and cable laying. In the Gulf of Mexico, the 

impacts from many of these threats are identified as either low or unknown (BOEMRE, 2011; 

BOEM, 2012c). 

IPFs that could potentially affect sperm whales include drilling rig presence, noise, and lights; 

support vessel and helicopter traffic noise; support vessel strikes; 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 dispersion, the small area of ocean affected, the intermittent nature of 

the discharges, and the mobility of these marine mammals. Compliance with 

NTL 2012-BSEE-G01 will minimize the potential for marine debris-related impacts on 

sperm whales. 

Impacts of Drilling Rig Presence, Noise, and Lights 

Some sounds produced by the drilling rig may be emitted at levels that could potentially disturb 

individual whales or mask the sounds animals would normally produce or hear. Noise associated 

with drilling is relatively weak in intensity, and an individual animal’s noise exposure would be 

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transient. As discussed in Section A.1, the bandwidth of sounds generated by the drilling rig is 

approximately 10 to 500 Hz. 

Sperm whales appear to have good low-frequency hearing, with variable responses to 

anthropogenic noise (Jochens et al., 2008). The sperm whale may possess better low-frequency 

hearing than some of the other odontocetes, although not as low as many baleen whale species 

that produce sounds within a bandwidth between 30 Hz and greater than 5 kHz (Wartzok and 

Ketten, 1999). Southall et al. (2007) lists sperm whales in the same hearing group 

(i.e., mid-frequency cetaceans) as dolphins, toothed whales, beaked whales, and bottlenose 

whales (estimated hearing range from 150 Hz to 160 kHz). Generally, most of the acoustic 

energy from sperm whales is present at frequencies below 4 kHz, although diffuse energy up to 

and past 20 kHz has been reported, with source levels up to 236 dB re 1 μPa at 1 m. Other 

studies indicate sperm whales’ wideband clicks contain energy between 0.1 and 20 kHz (Weilgart 

and Whitehead, 1993; Goold and Jones, 1995). Most observations of behavioral responses of 

marine mammals to anthropogenic sounds, in general, have been limited to short-term 

behavioral responses, which included the cessation of feeding, resting, or social interactions 

(NMFS, 2009a). 

Observations of sperm whales near offshore oil and gas operations suggest an inconsistent 

response to anthropogenic marine sound (Jochens et al., 2008). Sounds produced during drilling 

operations are generally constant (rather than pulsed or intermittent) and at levels that may be 

louder than, and of a similar frequency to, the auditory signal received by sperm whales. 

Animals can determine the direction from which a sound arrives based on cues, such as 

difference in arrival times, sound levels, and phases at the two ears. Thus, an animal’s 

directional hearing capabilities have a bearing on its vulnerability to masking (NRC, 2003a). 

Behavioral changes for marine mammals such as the sperm whale to auditory masking sounds 

may include producing more calls, longer calls, or shifting the frequency of the calls 

(NMFS, 2009a; Holt et al., 2009). 

In addition, there are other OCS facilities and activities near the lease area, and the region as a 

whole has a large number of similar sound sources. Drilling-related noise associated with this 

project will contribute to increases in the ambient noise environment of the Gulf of Mexico, but it 

is not expected in amplitudes sufficient enough to cause either hearing or behavioral effects to 

sperm whales. 

The drilling rig used during the proposed activity will be located within a deepwater, open ocean 

environment and will maintain position during drilling operations. Sounds generated by the rig 

and by drilling operations will be generally continuous with some variability in sound level. This 

analysis assumes that the continuous nature of sounds produced by the drilling rig will provide 

individual whales with cues relative to the direction and relative distance (sound intensity) of the 

sound source, and the fixed position of the drilling rig will provide multiple options for active 

avoidance of potential physical impacts. 

NMFS 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 (NMFS, 2007). The analysis noted that drilling rigs 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 offshore lighting and presence of drilling rigs and OCS vessels were considered potential 

factors affecting sperm whales, NMFS’s 2007 Biological Opinion and lease sale EISs (MMS, 

2007b; BOEM, 2012b,c, 2013) did not identify these as IPFs for sperm whales. Therefore, no 

significant impacts are expected. 

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Impacts of Support Vessel and Helicopter Traffic 

Support vessel traffic has the potential to disturb sperm whales. 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 are presented in the lease sale EIS (MMS, 2007b). 

To reduce the potential for vessel strikes, the BOEM has issued NTL 2012-JOINT-G01, 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 300 ft (91 m) or greater whenever possible. Vessel operators are 

required to reduce vessel speed to 10 knots or less, when safety permits, when mother/calf pairs, 

pods, or large assemblages of cetaceans are observed near an underway vessel. Compliance 

with this NTL will minimize the likelihood of vessel strikes as well as reduce the chance for 

disturbing sperm whales. 

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 (NMFS, 2007). With implementation of the mitigation 

measures in NTL 2012-JOINT-G01, NMFS concluded that the likelihood of collisions between 

vessels and sperm whales would be reduced to insignificant levels. 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 

maintain a distance of 295 ft (90 m) from sperm whales, 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 800 ft (245 m). A reaction to the initial pass of the aircraft was observed during 3 (12%) of 

24 sightings. All three reactions consisted of a hasty dive and occurred at less than 1,180 ft 

(360 m) 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. 

Helicopters maintain altitudes above 700 ft (213 m) during transit to and from the offshore 

working area. In the event that a whale is seen during transit, the helicopter will not approach 

or circle the animal(s). In addition, guidelines and regulations specify that helicopters maintain 

an altitude of 1,000 ft (305 m) within 300 ft (91 m) of marine mammals (BOEM, 2012a,b). 

Although whales may respond to helicopters (Smultea et al., 2008), NMFS (2007) and 

BOEM (2012a) 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 MMS (2007b) 

and BOEM (2012b,c, 2013) and the Biological Opinion for the Five-Year Oil and Gas Leasing 

Program in the Central and Western Planning Areas of the Gulf of Mexico (NMFS, 2007). Oil 

impacts on marine mammals are discussed by Geraci and St. Aubin (1990). For this 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 

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Shell’s OSRP will mitigate and reduce the potential for impacts on sperm whales. EP Section 9b

provides detail on spill response measures. Given the open ocean location of the lease area and 

the duration of a small spill, the 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 more than 90% would be evaporated or dispersed naturally 

within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 12 ac 

(0.5 to 5 ha), 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], 2011). 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 are expected. 

Impacts of a Large Oil Spill 

Potential spill impacts on marine mammals including sperm whales are discussed in 

MMS (2007b), BOEM (2012a,b,d), and in NMFS (2007). Oil impacts on marine mammals are 

discussed by Geraci and St. Aubin (1990). For this 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, 2011). 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. The level of impact of oil exposure 

depends on the amount, frequency, and duration of exposure; route of exposure; and type or 

condition of petroleum compounds or chemical dispersants (Waring et al., 2013). 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, 2011). Ackleh et al. (2012) hypothesized that sperm 

whales may have temporarily relocated away from areas near the Macondo spill in 2010. 

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 2012-JOINT-G01 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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on sperm whales are expected. 

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C.3.2 West Indian Manatee (Endangered) 

Most of the Gulf of Mexico 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, with some individuals traveling as far west as Texas 

(Fertl et al., 2005). A species description is presented in MMS (2007b) and in the recovery plan 

for this species (USFWS, 2001). 

IPFs that could potentially affect 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 65 miles (105 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. Compliance with NTL 2012-BSEE-G01 will minimize the 

potential for marine debris-related impacts on manatees. Consistent with the analysis in 

BOEM (2012a), impacts of routine project-related activities on the manatee would be negligible. 

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 BOEM has issued NTL 2012-JOINT-G01, 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 NTL 2012-JOINT-G01 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 relatively low altitudes of 66 to 525 ft (20 to 160 m). Helicopters 

used in support operations maintain a minimum altitude of 700 ft (213 m) while in transit 

offshore, 1,000 ft (305 m) over unpopulated areas or across coastlines, and 2,000 ft (610 m) 

over populated areas and sensitive habitats such as wildlife refuges and park properties. In 

addition, guidelines and regulations specify that helicopters maintain an altitude of 1,000 ft (305 

m) within 300 ft (91 m) of marine mammals (BOEM, 2012a,b). 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 large oil 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, 2011). 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, 2011). 

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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 2012-JOINT-G01 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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides 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) have also 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, it is unlikely that any 

endangered mysticete would come into contact with any project activities, either routine 

operations or accidents. 

Mysticete whales were not included as affected species in the Biological Opinion for the Five-Year 

Oil and Gas Leasing Program in the Central and Western Planning Areas of the Gulf of Mexico 

(NMFS, 2007). Potential impacts analyzed in MMS (2007b) and BOEM (2012a,b,d) are 

incorporated by reference. If any of these whales were present in the area, potential impacts 

would be the same as those discussed 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 may be found in the Gulf of Mexico, including 2 species of 

mysticete whales, the dwarf and pygmy sperm whales, 4 species of beaked whales, and 

14 species of delphinids (see EP Section 6h). All marine mammals are protected species under 

the MMPA. The most common non-endangered cetaceans in the deepwater environment are 

odontocetes such as the pantropical spotted dolphin, spinner dolphin, and Clymene dolphin. 

A brief summary is presented in this section, and additional information on these groups is 

presented in MMS (2007b). 

Mysticete whales. Two species of 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 (Balaenoptera edeni) has been sighted most frequently along the 328-ft (100-

m) 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; Waring et al., 2013). 

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 3,281 ft 

(1,000 m) over lower slope and abyssal landscapes (Davis et al., 2000). Any of these species 

could occur in the lease area (Waring et al., 2013). 

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 (Waring et al., 2013). 

The bottlenose dolphin (Tursiops truncatus) is a common inhabitant of the northern Gulf of 

Mexico, particularly within continental shelf waters. There are two ecotypes of bottlenose 

dolphins, a coastal form and an offshore form, which are genetically isolated from each other 

(Waring et al., 2013). The offshore form of the bottlenose dolphin may occur within the lease 

area. Inshore populations of coastal bottlenose dolphins in the northern Gulf of Mexico are 

separated by the NMFS into 37 geographically distinct population units, or stocks, for 

management purposes (Waring et al., 2013). NMFS (2013) has proposed to classify the Gulf of 

Mexico Northern Coastal Stock, Western Coastal Stock, and all 32 of the Bay, Sound, and 

Estuarine Stocks as strategic stocks. A “strategic” stock is defined by the MMPA as a marine 

mammal stock. 

 for which the level of direct human-caused mortality exceeds the potential biological 

removal level; 

 which, based on the best available scientific information, is declining and is likely to be 

listed as a threatened species under the ESA within the foreseeable future; or 

 which is listed as a threatened or endangered species under the ESA, or is designated as 

depleted under the MMPA. 

The strategic stock designation in this case was based primarily on the occurrence of an “Unusual 

Mortality Event” (UME) of unprecedented size and duration that has affected these stock areas. 

This UME began in February 2010 and, as of late 2013, the event was still considered to be 

ongoing (NOAA, 2013; Waring et al., 2013). Carmichael et al. (2012) hypothesized that the 

unusual number of bottlenose dolphin strandings in the northern Gulf of Mexico during this time 

may have been associated with environmental perturbations, including sustained cold weather 

and the Macondo spill in 2010, as well as large volumes of cold freshwater discharge in the early 

months of 2011. 

IPFs that could potentially affect non-endangered marine mammals include drilling rig 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 

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discharges, and the mobility of marine mammals. Compliance with NTL 2012-BSEE-G01 will 

minimize the potential for marine debris-related impacts on marine mammals. 

Impacts of Drilling Rig Presence, Noise, and Lights 

Noise from routine drilling activities has the potential to disturb marine mammals. Most 

odontocetes (toothed whales and dolphins) use higher frequency sounds than those 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. Stronger noise levels will 

occur during thruster use in dynamic positioning. Thruster noise impacts would be expected at 

greater distances than vessel noise alone (LGL Ecological Research Associates, Ltd., 2006) but 

are dependent on variables relating to thruster type and usage. It is expected that marine 

mammals within or near the lease area would be able to detect the presence of the drilling rig 

and avoid exposure to higher energy sounds, particularly within an open ocean environment. 

Some odontocetes have shown increased feeding activity around lighted platforms at night (Todd 

et al., 2009). Even temporary drilling rigs present an attraction to pelagic food sources that may 

attract cetaceans (and sea turtles). Therefore, prey congregation could pose an attraction to 

protected species that exposes them to higher levels or longer durations of noise that might 

otherwise be avoided. 

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, timing, and geographic extent 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. 

Drilling rig lighting and presence are not identified as IPFs for marine mammals in MMS (2007b) 

or BOEM (2012a,b,c). Therefore, no significant impacts are expected. 

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 are presented in the lease sale 

EIS (MMS, 2007b). To reduce the potential for vessel strikes, the BOEM and BSEE have issued 

NTL 2012-JOINT-G01, 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. Vessel operators and crews are required to attempt to 

maintain a distance of 300 ft (91 m) or greater when whales are sighted and 150 ft (45 m) 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 700 ft (213 m) during transit to and 

from the working area. In addition, guidelines and regulations specify that helicopters maintain 

an altitude of 1,000 ft (305 m) within 300 ft (91 m) of marine mammals (BOEM, 2012a,b). This 

altitude will minimize the potential for disturbing marine mammals, and no significant impacts are 

expected (BOEM, 2012a,b). 

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Impacts of a Small Fuel Spill 

Potential spill impacts on marine mammals are discussed in MMS (2007b) and BOEM (2012a,b,d), 

and oil impacts on marine mammals in general are discussed in Geraci and St. Aubin (1990). For 

this 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, including 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. EP Section 9b provides detail on 

spill response measures. Given the open ocean location of the lease area and the duration of a 

small spill, the 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 diesel fuel on the sea surface would range from 1.2 to 12 ac (0.5 to 5 ha), 

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, 2011). 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 MMS (2007b), BOEM (2012a,b,d), 

and in Geraci and St. Aubin (1990). For this EP, there are no unique site-specific issues. 

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, 2011). 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, 2011). 

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 2012-JOINT-G01 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 EP Section 2j. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the impacts. EP Section 9b provides detail on spill 

response measures. Therefore, no significant spill impacts on marine mammals are expected. 

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C.3.5 Sea Turtles (Endangered/Threatened) 

As listed in 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 distinct 

population segment (DPS) of loggerhead turtle (Caretta caretta) that occurs in the Gulf of Mexico 

is listed as threatened, although other DPSs are endangered. 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 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. 

Sea turtle nesting in the northern Gulf of Mexico can be summarized by species as follows: 

 Loggerhead turtles – Loggerhead turtles nest in significant numbers along the Florida 

Panhandle and, to a lesser extent, from Texas through Alabama (NMFS and USFWS, 

2008). 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, 2013a,b); 

 Kemp’s ridley turtles – The main nesting site of the Kemp’s ridley turtle is Rancho Nuevo 

beach, Tamaulipas, Mexico (NMFS et al., 2011). 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 nesting in Alabama (Share the Beach,2014); and 

 Hawksbill turtles – Hawksbill turtles typically do not nest anywhere near the project area 

(USFWS, 2013). 

IPFs that could potentially affect sea turtles include drilling rig 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 2012-BSEE-G01 will minimize the potential for marine debris-related 

impacts on sea turtles. 

Impacts of Drilling Rig 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 

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from the area. Due to the limited scope, timing, and geographic extent 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). 

NMFS (2007) concluded that the effects of lighting from offshore structures on sea turtles are 

insignificant. Therefore, no significant impacts are expected. 

Impacts of 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 BOEM and BSEE have issued NTL 2012-JOINT-G01, 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 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 150 ft 

(45 m) 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). Therefore, 

no significant impacts are expected. 

Helicopter traffic also has the potential to disturb sea turtles. However, while flying offshore, 

helicopters maintain altitudes above 700 ft (213 m) 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 MMS (2007b), BOEM (2012b,c, 2013), and 

in 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 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, including 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. EP Section 9b provides 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 more than 90% would be evaporated or dispersed naturally 

within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 12 ac 

(0.5 to 5 ha), 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 (MMS, 2007b; NMFS, 2010b; BOEM, 2012b,c, 2013). 

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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 because 

the lease area is 65 miles (105 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, dispersants, and 

beach cleanup activities). 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 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 (MMS, 2007b; 

NMFS, 2010c). 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. EP Section 9b

provides 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 30 days. The nearest significant nesting area of loggerhead 

turtles is found on beaches within the Breton NWR. 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). 

NOAA’s Office of Response and Restoration prepared guidelines in 2007 to minimize impacts to 

nesting activities and existing nests due to beach cleanup activities (Shigenaka et al., 2010). Oil 

spill cleanup activities on the beach (e.g., raking, shoveling, use of mechanical equipment) may 

adversely affect sea turtle nesting activity or existing beach nests. Response workers and 

vehicles may crush eggs and compact beach sand, making it difficult or impossible for hatchlings 

to emerge or for females to use for nesting (Shigenaka et al., 2010). Nighttime human activity 

can prevent sea turtles from coming ashore, may cause females to stop nesting and return to the 

ocean, disorient or impede emerging hatchlings, and crush hatchlings attempting to reach the 

ocean. 

Impacts to sea turtles from a large oil spill and associated cleanup activities would be dependent 

upon spill extent, duration, and season (relative to turtle nesting season); the amount of oil 

reaching the shore; the importance of specific beaches to sea turtle nesting; and the level of 

cleanup vessel and beach crew activity required. A blowout resulting in a large oil spill is an 

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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 EP Section 2j. In the unlikely event of 

a spill, implementation of Shell’s OSRP would mitigate and reduce direct and indirect impacts to 

turtles from oil exposure and response activities and materials. EP Section 9b provides detail 

on spill response measures. 

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 1). 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 

MMS (2007b). 

A large oil spill is the only IPF that could potentially affect 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 67 miles (108 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 habitats for the wintering Piping Plover could be contacted by a spill within 

30 days. Plaquemines Parish, Louisiana, which has the highest probability of contact for the 

30-day interval (8%), includes critical habitat of Piping Plovers. 

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Figure 1. Location of selected environmental features in relation to the lease area. (EFH = Essential Fish Habitat; HAPC = Habitat Area of 

Particular Concern.) 

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Plovers could become externally oiled while foraging on oiled shores or be exposed internally 

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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides 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 (National Wildlife Federation, 2012). 

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 278 at Aransas/Wood Buffalo 

National Park in August 2011 (Whooping Crane Eastern Partnership, 2013). A non-migrating 

population has been reintroduced in central Florida, and another reintroduced 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 22,240 ac (9,000 ha) 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 1). A species description is presented in MMS (2007b) 

and BOEM (2012b,c). 

A large oil spill is the only IPF that could potentially affect Whooping Cranes due to the distance 

from Aransas NWR. 

Impacts of a Large Oil Spill 

A large oil spill has a low probability of affecting Whooping Cranes because the lease area is 

approximately 454 miles (730 km) from its critical habitat (Aransas NWR, Texas) and the 

likelihood of contact with the habitat is extremely low (BOEM, 2012b). 

In the event of oil exposure, Whooping Cranes could become externally oiled while foraging in 

oiled areas or internally exposed to oil 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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on Whooping Cranes are expected. 

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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, 

2010d) (Figure 1). A species description is presented in MMS (2007b) and in the recovery plan 

for this species (USFWS and Gulf States Marine Fisheries Commission, 1995). 

A large oil spill is the only IPF that could potentially affect Gulf sturgeon. There are no IPFs 

associated with routine project activities that could affect this species. 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 MMS (2007b), BOEM (2012b,c, 2013), 

and in 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 EP, there are no unique 

site-specific issues with respect to this species. 

The lease area is about 132 miles (212 km) from the nearest Gulf sturgeon critical habitat. 

OSRA modeling (Table 3) predicts that a spill in the lease area would have a 1% chance of 

contacting Gulf sturgeon critical habitat in coastal areas of Okaloosa County, Florida, 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 a 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 

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. 

EP Section 9b provides 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, Choctawhatchee, 

Perdido Key, and St. Andrew beach mouse. Critical habitat has been designated for all four 

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subspecies; Figure 1 shows the critical habitat combined for all four subspecies. Species 

descriptions are provided in MMS (2007b). 

A large oil spill is the only IPF that could potentially affect 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 onshore support activities near their habitat. 

Impacts of a Large Oil Spill 

Potential spill impacts on beach mice are discussed in MMS (2007b) and BOEM (2012b,c, 2013). 

For this EP, there are no unique site-specific issues with respect to these species. 

The lease area is about 163 miles (262 km) from the nearest beach mouse critical habitat. 

OSRA modeling predicts that a spill in the lease area would have a 1% chance of contacting 

beach mouse critical habitat in Okaloosa County, Florida, within 30 days. 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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides 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 

(shearwaters, storm petrels, boobies); summer residents that breed in the Gulf (Sooty Tern, 

Least Tern, Sandwich Tern, Magnificent Frigatebird); winter residents (gannets, gulls, jaegers); 

and permanent resident species (Laughing Gull, Royal Tern, 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. 

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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. 

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 that could potentially affect marine and pelagic birds include drilling rig 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 permitted under the NPDES general permit 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 2012-BSEE-G01 will minimize the potential for marine debris-related impacts on birds. 

Impacts of Drilling Rig 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). 

Conversely, 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). 

Overall, potential negative impacts to birds from drilling rig lighting, potential collisions, or other 

adverse effects are highly localized, relatively short term and temporary in nature, and may be 

expected to affect only individual birds during migration periods. Therefore, these potential 

impacts are not expected to affect birds at the population or species level and are not significant 

(BOEM, 2012b, 2013). 

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 MMS (2007b) and BOEM (2012b,c, 2013). 

For this 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 marine and pelagic birds. 

EP Section 9b provides detail on spill response measures. Given the open ocean location of the 

lease area and the short duration of a small spill, the potential exposure for pelagic marine birds 

would be brief. 

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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 more than 90% would be evaporated or dispersed naturally 

within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 12 ac 

(0.5 to 5 ha), 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 

VOCs. Because of 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 marine and 

pelagic birds would be expected. 

Impacts of a Large Oil Spill 

Potential spill impacts on marine and pelagic birds are discussed in MMS (2007b) and BOEM 

(2012b,c, 2013). For this 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 (>656 ft [>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. 

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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on marine and pelagic birds are expected. 

C.4.2 Shorebirds and Coastal Nesting Birds 

Threatened and endangered bird species (Piping Plover and Whooping Crane) are discussed 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 

nest on beaches, flats, dunes, bars, barrier islands, and similar coastal and nearshore 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 MMS (2007b) and BOEM (2012b). 

The Brown Pelican (Pelecanus occidentalis) was delisted from federal endangered status in 2009 

(USFWS, 2010c). However, this species remains listed as endangered by the State of Louisiana 

(State of Louisiana Department of Wildlife and Fisheries, 2013), is listed as a species of greatest 

conservation need by the State of Mississippi (Mississippi Department of Wildlife, Fisheries and 

Parks, 2005), and is designated as a species of special concern by the State of Florida (Florida 

Fish and Wildlife Conservation Commission, 2013c). 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 

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southeastern population of Brown Pelicans lives in the northern Gulf Coast, generally nesting on 

protected islands (USFWS, 2010b). 

IPFs that could potentially affect shorebirds and coastal nesting birds include support vessel and 

helicopter traffic and a large oil spill. 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 2012-BSEE-G01 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 among 

species and individuals (Rodgers and Schwikert, 2002). The disturbances will be limited to 

flushing birds away from vessel pathways; known distances are from 65 to 160 ft (20 to 49 m) 

for personal watercraft and 75 to 190 ft (23 to 58 m) for outboard-powered boats (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 nesting birds, eggs, and chicks will not 

be disturbed. Vessel operators will use designated navigation channels and comply with posted 

speed and wake restrictions while transiting sensitive inland waterways. Due to the limited 

scope, duration, and geographic extent of drilling activities, any short-term impacts are not 

expected to be significant to coastal bird populations. 

Aircraft traffic can cause some disturbance to birds on shore and off shore. Responses are highly 

dependent on the type of aircraft, bird species, 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 2,000 ft (610 m) 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 in Efroymson et al. (2000). With these 

guidelines in effect, it is likely that individual birds would experience, at most, only short-term 

behavioral disruption. The potential impacts are not expected to be significant to bird 

populations or species in the project area. 

Impacts of Large Oil Spill 

Coastal birds can be exposed to oil as they float on the water surface, dive during foraging, or 

wade in oiled coastal waters. 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. 

Studies concerning the Macondo spill provide additional information regarding impacts on 

shorebirds and coastal nesting birds that may be affected in the event that a large oil spill 

reaches coastal habitats. Although the Macondo spill had direct and indirect impacts to coastal 

and marine birds, it is premature to conclude impacts over a long period (BOEM, 2012b). 

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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

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reduce the impacts. EP Section 9b provides 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). A study by Ross et al. (2012) on midwater fauna to characterize 

vertical distribution of mesopelagic fishes in selected deepwater areas in the Gulf of Mexico 

substantiated high species richness, but general domination by relatively few families and 

species. 

IPFs that could potentially affect pelagic communities and ichthyoplankton include drilling rig 

presence, noise, and lights; effluent discharges; water intakes; and two types of accidents – a 

small fuel spill and a large oil spill. 

Impacts of Drilling Rig Presence, Noise, and Lights 

The drilling rig, as a floating structure in the deepwater environment, will act as a fish-attracting 

device (FAD). 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 drilling rig is a single, temporary structure, impacts on fish populations, 

whether beneficial or adverse, are considered minor. 

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. 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). NPDES permit limits and requirements will be met. 

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 will 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 will be diluted rapidly to 

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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 several meters below the ocean surface for various services 

including firewater and once-through non-contact cooling of machinery on the drilling rig 

(EP Table 7a). 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. GMG290000 specifies 

requirements for new facilities for which construction commenced after July 17, 2006 with a 

cooling water intake structure having a design intake capacity of greater than two million gallons 

of water per day, of which at least 25% is used for cooling purposes. 

The wells will be drilled using either a drillship or DP semisubmersible rig. If the drilling vessel 

selected for this project meets the described applicability for new facilities, the vessel’s water 

intakes are expected to be in compliance with the design, monitoring, and recordkeeping 

requirements of the NPDES permit. 

Impacts of a Small Fuel Spill 

Potential spill impacts on fisheries resources are discussed in MMS (2007b) and 

BOEM (2012a,b,d). For this 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. EP Section 9b provides 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 more than 90% would be evaporated or dispersed naturally 

within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 12 ac 

(0.5 to 5 ha), 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, a small 

fuel spill would be unlikely to produce detectable impacts on pelagic communities. 

Impacts of a Large Oil Spill 

Potential spill impacts on pelagic communities and ichthyoplankton are discussed in 

BOEM (2012a,b,d). For this EP, there are no unique site-specific issues. 

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 

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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 in 

the upper layers of the water column are especially vulnerable to oiling; certain toxic fractions of 

spilled oil may be lethal to these life stages. 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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides 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 

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 

600 ft (183 m). 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 located 53 miles (85 km) northwest 

of the lease area. 

EFH has been identified in the deepwater Gulf of Mexico for highly migratory pelagic fishes, 

which occur as transients in the lease area. 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, 2009b): 

 Atlantic bluefin tuna (spawning, 

eggs, larvae, adults) 

 Atlantic skipjack tuna (spawning, 

adults) 

 Atlantic swordfish (larvae, 

juveniles, adults) 

 Atlantic yellowfin tuna (spawning, 

juveniles, adults) 

 Bigeye thresher shark (all) 

 Bigeye tuna (juveniles, adults) 

 Blue marlin (juveniles, adults) 

 Longbill spearfish (juveniles, 

adults) 

 Longfin mako shark (all) 

 Oceanic whitetip shark (all) 

 Sailfish (adults) 

 Silky shark (all) 

 White marlin (juveniles, adults)

Research indicates the central and western Gulf of Mexico may be important spawning habitat for 

Atlantic bluefin tuna, and NMFS (2009b) 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 1). The areal extent of the HAPC is approximately 115,830 mi2 

(300,000 km2). 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, 2009b). 

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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 1). The nearest of these is Jakkula Bank, located 155 miles (250 km) west of the lease 

area. 

Routine IPFs that could potentially affect EFH and fisheries resources include drilling rig presence, 

noise, and lights; effluent discharges; and water intakes. In addition, two types of accidents – a 

small fuel spill and a large oil spill may potentially affect EFH and fisheries resources. 

Impacts of Drilling Rig Presence, Noise, and Lights 

The drilling rig, 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, 

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. 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 mud 

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 EFH from effluent discharges are anticipated to be similar to those described in 

Section C.5.1 for pelagic communities. 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, timing, and 

geographic extent 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 

Potential spill impacts on EFH are discussed in MMS (2007b) and BOEM (2012a,b,d). For this 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 EFH. EP Section 9b provides 

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 more than 90% would be evaporated or dispersed naturally 

within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 12 ac 

(0.5 to 5 ha), depending on sea state and weather conditions. 

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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 impact on water quality in the HAPC for 

spawning Atlantic bluefin tuna, which covers much of the deepwater Gulf of Mexico. The 

affected area would represent a negligible portion of the HAPC, which covers approximately 

115,830 mi2 (300,000 km2) of the Gulf of Mexico. Therefore, no significant spill impacts on EFH 

for highly migratory pelagic fishes are expected. 

A small fuel spill would not affect EFH for corals and coral reefs; the nearest coral EFH is located 

53 miles (85 km) northwest of the lease area. A small fuel spill would float and dissipate on the 

sea surface and would not contact these features. Therefore, no significant spill impacts on EFH 

for corals and coral reefs are expected.

Impacts of a Large Oil Spill 

Potential spill impacts on EFH are discussed in MMS (2007b) and BOEM (2012a,b,d). For this 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, 2009b), some impact on EFH would be unavoidable. 

A large spill could affect the EFH for many managed species including shrimps, stone crab, spiny 

lobster, corals and coral reefs, reef fishes, coastal migratory pelagic fishes, red drum, and highly 

migratory pelagic fishes. It would result in adverse impacts on water quality and water column 

biota including phytoplankton, zooplankton, ichthyoplankton, and nekton. In coastal waters, 

sediments could be contaminated and result in persistent degradation of the seafloor habitat for 

managed demersal fish and invertebrates. 

The lease area is within the HAPC for spawning Atlantic bluefin tuna (NMFS, 2009b). 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 and their offspring. 

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, 2009b). 

The nearest feature designated as EFH for corals is located 53 miles (85 km) northwest of the 

lease area. An accidental spill would be unlikely to reach or affect this feature. 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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on EFH are expected. 

C.6 Archaeological Resources 

C.6.1 Shipwreck Sites 

MC 943 is on the list of archaeological survey blocks determined to have a high potential for 

containing archaeological properties (BOEM, 2012d). A geologic, stratigraphic, and 

archaeological assessment detected marine avoidance targets within 2,000 ft (610 m) of each of 

the proposed wellsites, but none were identified as shipwrecks (GEMS, 2013; C&C, 2007). 

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Because there are no historic shipwreck sites in the lease area (see EP Section 6), there are no 

routine IPFs that are likely to affect these resources. A small fuel spill would not affect 

shipwrecks in adjoining blocks because the oil would float and dissipate on the sea surface. The 

impact of a large oil spill that could contact shipwrecks in other areas is considered below a level 

of concern. 

Impacts of a Large Oil Spill 

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 

3,600 ft (1,100 m), 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 contact shipwreck sites beyond 

the 984-ft (300-m) radius estimated by MMS (2007a, 2008), depending on its extent, trajectory, 

and persistence. 

BOEM (2012b) reexamined the analyses for archaeological resources presented in MMS (2007a, 

2008) based on additional information available since the publication of these two documents 

and in consideration of the Macondo oil spill. Substantial new information that alters the initial 

impact conclusion for archaeological resources has come to light as a result of BOEM-sponsored 

studies and industry surveys. Specifically, evidence of damage to significant cultural resources 

(i.e., historic shipwrecks) has been shown to have occurred because of an incomplete knowledge 

of seafloor conditions in lease areas >200 m (>656 ft) deep that have been exempted from highresolution surveys. Since significant historic shipwrecks have been recently discovered outside 

the previously designated high-probability areas (some of which show evidence of impacts from 

permitted activities prior to their discovery), BOEM now requires that operators submit an 

archaeological survey for exploration and development projects. 

There are no known historic shipwrecks in the lease area and a spill entering shallow coastal 

waters could conceivably contaminate an undiscovered or known historic 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. 

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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on historic shipwrecks are expected. Also as noted in 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. However, more recent studies suggest that the impacts could be longer term 

and not easily reversible (BOEM, 2012b,c). 

C.6.2 Prehistoric Archaeological Sites 

With water depths ranging from approximately 4,211 to 4,276 ft (1,284 to 1,303 m), the wellsites 

are well beyond the 60-m (197-ft) depth contour used by the BOEM as the seaward extent for 

prehistoric archaeological site potential in the Gulf of Mexico. A geologic, stratigraphic, and 

archaeological assessment detected marine avoidance targets within 2,000 ft (610 m) of the 

proposed wellsites (GEMS, 2013; C&C, 2007) but none were suggestive of submerged cultural 

resources. Because prehistoric archaeological sites are not found in the lease area, the only 

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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. MMS (2007b) estimates that a severe 

subsurface blowout could resuspend and disperse sediments within a 984-ft (300-m) radius. 

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). BOEM (2012b) notes that some unavoidable direct 

and indirect impacts on coastal historic resources could occur, resulting in the loss of information. 

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 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides 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 northern Gulf of Mexico that may be affected by oil and gas activities are 

described in previous EISs (MMS, 2007b; BOEM, 2012a,b,d, 2013) 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 northern 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 activities occurring in 

the lease area 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 a wildlife refuge or a 

wilderness area. Potential impacts of support vessel traffic are briefly addressed in this section. 

A small fuel spill in the lease area would be unlikely to affect coastal habitats, because it would 

not be expected to make landfall or reach coastal waters prior to breaking up (see explanation in 

Section A.9.2).

Impacts of Support Vessel Traffic 

For OCS activities in general, support operations, including the crew boat 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 the crew boat and supply boats as detailed in 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. 

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Impacts of a Large Oil Spill 

Potential spill impacts on coastal habitats are discussed in MMS (2007b) and BOEM (2012a,b,d). 

Coastal habitats inshore of the project area include barrier beaches and dunes, wetlands, and 

submerged seagrass beds. For this 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. Nearshore waters and embayments of Plaquemines Parish, 

Terrebonne Parish, and Lafourche Parish, Louisiana, have the highest probability of contact 

within 30 days. After 30 days, 11 counties or parishes may be contacted from Texas to Florida. 

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 EISs (MMS, 2007b; BOEM, 2012b) 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: 

 Anahuac NWR 

 Apalachicola Bay Aquatic Preserve 

Outstanding Florida Water 

 Apalachicola National Estuarine 

Research Reserve 

 Apalachicola River and Bay Surface 

Water Improvement and 

Management (SWIM) Area 

 Apalachicola River Wildlife and 

Environmental Area 

 Apffel Park 

 Aransas NWR 

 Atchafalaya Delta Wildlife 

Management Area (WMA) 

 Atkinson Island WMA 

 Bayou Portage Coastal Preserve 

 Bayou Sauvage NWR 

 Bayou Teche NWR 

 Bellefontaine Point Coastal 

Reserve 

 Big Boggy NWR 

 Big Branch Marsh NWR 

 Big Lagoon State Recreation Area 

 Biloxi Marshes State Coastal 

Preserve 

 Biloxi River Coastal Reserve 

 Biloxi WMA 

 Bon Secour NWR 

 Brazoria NWR 

 Breton NWR 

 Buccaneer State Park 

 Cameron Prairie NWR 

 Candy Abshier WMA 

 Choctawatchee Bay SWIM Area 

 Christmas Bay Coastal Preserve 

 Christmas Bay State Park 

 Cypremort Point State Park 

 Davis Bayou Coastal Preserve 

 Deer Island State Coastal Preserve 

 Deer Lake State Park 

 Delta NWR 

 Fort Pickens State Park Aquatic 

Preserve 

 Fort Anahuac Park 

 Galveston Island State Park 

 Goose Island State Park 

 Grand Bay National Estuarine 

Research Reserve 

 Grand Bay NWR 

 Grand Bay Savannah Coastal 

Preserve 

 Grand Bayou Coastal Preserve 

 Grand Isle State Park 

 Graveline Bay Coastal Reserve 

 Grayton Beach State Park 

Outstanding Florida Water 

 Guadalupe Delta WMA 

 Gulf Islands National Seashore 

 Gulf State Park 

 Hancock County Marsh Coastal 

Reserve 

 Henderson State Park 

 Isles Dernieres Barrier Islands 

Refuge 

 Jean Lafitte National Historical 

Park and Preserve 

 Jourdan River Coastal Reserve 

 Lacassine NWR 

 Lafitte Woods NA 

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 Laguna Madre Estuarine and 

Coastal Marine Area 

 Lake Corpus Christi SP 

 Lillian Swamp Mitigation Area 

 Little Pecan Island NA 

 Lower Neches WMA 

 Mad Island WMA 

 Mandalay NWR 

 Meaher State Park 

 Marsh Island WMA 

 Matagorda Island State Park 

 Mcfaddin NWR 

 Meaher State Park 

 Mission-Aransas National Estuarine 

Research Reserve 

 Mississippi Sandhill Crane NWR

 J.D. Murphree WMA 

 Mustang Island SP 

 Old Fort Bayou Coastal Reserve 

 Old Fort Travis Park 

 Padre Island National Seashore 

 Pascagoula River Coastal Reserve 

 Pass A Loutre WMA 

 Paul J. Rainey WMA 

 Peach Point WMA 

 Pearl River WMA 

 Penalver State Park 

 Pensacola Bay SWIM Area 

 Perdido Key State Recreation Area 

 Peveto Woods NA 

 Point Au Chein WMA 

 Point Washington Outstanding 

Florida Water 

 Salvador WMA 

 San Bernard NWR 

 Sea Rim State Park 

 Seawolf Park 

 Shell Keys NWR 

 St. Andrew Bay Watershed SWIM 

Area 

 St. Andrews State Park 

 St. Andrews State Park Aquatic 

Preserve 

 St. Bernard State Park 

 St. George Island State Park 

 St. Joseph Bay State Buffer 

Preserve 

 St. Joseph Peninsula State Park 

 St. Vincent NWR 

 Tarkiln Bayou State Preserve 

 Texas Point NWR 

 The Grand Bay Savanna Tract 

 W.L. Holland WMA 

 Weeks Bay National Estuarine 

Research Reserve 

 Welder Flats Coastal Preserve 

 Winser WMA 

 Wolf River Coastal Reserve 

 Yellow River WMA 

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 Port Aransas Park 

 Rockefeller WMA 

 Sabine NWR 

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. 

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-andwater 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. 

Coastal wetlands are highly sensitive to oiling and can be significantly impacted because of the 

inherent toxicity of hydrocarbon and non-hydrocarbon components of the spilled substances 

(Mendelssohn, 2012). The MMS (2007b) predicted that for every 50 bbl of oil contacting wetlands, 

approximately 6.7 ac (2.7 ha) 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 (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 EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides 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 

BOEM has reexamined the analysis for recreational and commercial fishing presented in MMS (2007b, 

2008) based on additional information and in consideration of the Macondo spill. No new information 

was found that would alter the potential impacts on commercial fishing (BOEMRE, 2011; BOEM, 

2012c). 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. 

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 (Pleoticus robustus) are caught by trawlers in water 

depths of about 820 to 1,804 ft (250 to 550 m). Tilefishes (primarily Lophalotilus chamaeleonticeps) 

are caught by bottom longlining in water depths from about 540 to 1,476 ft (165 to 450 m) 

(Continental Shelf Associates, Inc., 2002). The proposed project is in 4,211 to 4,276 ft (1,284 to 

1,303 m) of water. No conflict with commercial fishing activity other than longlining is expected to 

occur. 

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Most recreational fishing activity in the region occurs in water depths less than 656 ft (200 m) 

(Continental Shelf Associates, Inc., 1997, 2002). In deeper water, the main attraction to recreational 

fishers would be petroleum platforms in offshore waters of Texas and Louisiana. 

The only routine IPF that could potentially affect fisheries is drilling rig presence (including noise and 

lights). Two types of potential accidents are also addressed in this section – a small fuel spill and a 

large oil spill. 

Impacts of Drilling Rig Presence 

There is a slight possibility of pelagic longlines becoming entangled in the drilling rig. 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. EP Section 9b provides 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, if any, could be interrupted in the event of a small fuel 

spill. The area of diesel fuel on the sea surface would range from 1.2 to 12 ac (0.5 to 5 ha), 

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).

Impacts of a Large Oil Spill 

Potential spill impacts on fishing activities are discussed in MMS (2007b) and BOEM (2012b,c, 2013). 

For this 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. 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 EP Section 2j. In the unlikely event of a spill, 

implementation of Shell’s OSRP will mitigate and reduce the impacts. EP Section 9b provides 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 in this section. 

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. EP Section 9b provides detail on spill response 

measures. 

A small fuel spill would not have impacts on public health and safety because it would likely affect only 

a small area of the open ocean 65 miles (105 km) from the nearest shoreline and nearly all of the 

diesel fuel would evaporate or disperse naturally within 24 hours. Response crews would be equipped 

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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 drilling rig maintains 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, through skin 

contact or inhalation of VOCs. Crude oil is a highly flammable material, and any smoke or vapors from 

a crude oil fire can cause irritation. Exposure to large quantities of crude oil may pose a health 

hazard. 

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 EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides 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 shore-based 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 in this section. 

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. EP Section and 9b provides detail on spill response 

measures. Given the open ocean location of the lease area and the duration of a small spill, the 

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. 

Impacts of a Large Oil Spill 

Potential socioeconomic impacts of an oil spill are discussed in MMS (2007b) and BOEM (2012b,c, 

2013). For this EP, there are no unique site-specific issues with respect to employment and coastal 

infrastructure. A large spill could cause several types of economic impacts: extensive fishery closures 

could put fishermen out of work; temporary employment could increase as part of the response effort; 

adverse publicity could reduce employment in coastal recreation and tourism industries; and OCS 

drilling activities, including service and support operations that are an important part of local 

economies, could be suspended. 

The lease area is 65 miles (105 km) from the nearest shoreline. Based on the OSRA modeling 

predictions (Table 3), coastal areas of Texas, Louisiana, and Florida 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 EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on employment and infrastructure are expected. 

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C.8.4 Recreation and Tourism 

BOEM has reexamined the analyses for recreation and tourism presented in MMS (2007b, 2008) based 

on additional information and in consideration of the Macondo oil spill event. No new information was 

found that would alter the potential impacts on recreation and tourism (BOEMRE, 2011; BOEM, 

2012c).

There are no known recreational uses of the lease area. Recreational resources and tourism in coastal 

areas would not be affected by routine activities due to the distance from shore. Compliance with NTL 

2012-BSEE-G01 will minimize the chance of trash or debris being lost overboard from the drilling rig 

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. EP Section 9b provides 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 MMS (2007b) and BOEM 

(2012a,b,d). For this 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 wetlands, 

resulting in negative publicity that encourages people to stay away. The OSRA results summarized in 

Table 3 predict that shorelines of Texas, Louisiana, and Florida could be affected within 30 days. 

Nearshore waters and embayments of Plaquemines Parish, Terrebonne Parish, and Lafourche Parish, 

Louisiana, have the highest probability of contact within 30 days. 

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 EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides 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 MMS (2007b) and BOEM (2012b,c, 2013). 

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 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 accident IPF. A small fuel spill would not have 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, 25 temporary staging areas were 

established in Louisiana, Mississippi, Alabama, and Florida for spill response and cleanup efforts 

(BOEM, 2012b). 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. 

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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 EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on land use are expected. 

C.8.6 Other Marine Uses 

The lease area is not located within any USCG-designated fairway or shipping lane and MC 943 is not 

in a designated Military Warning Area. Shell will comply with BOEM requirements and lease 

stipulations to avoid impacts on uses of the area by military vessels and aircraft. There are no existing 

wells, flowlines, or umbilicals in the vicinity of the proposed wellsites (GEMS, 2013). 

The geologic, stratigraphic, and archaeological assessment detected marine avoidance targets within 

2,000 ft (610 m) of all of the proposed wellsites. A discontinued industrial waste disposal site is 

located northwest of the lease area. Shell’s procedure “Waste Barrel Avoidance and Release Response 

in the Mississippi Canyon Area,” which was approved by MMS and BOEM, applies to operations that 

could cause a disturbance of a seafloor barrel. Shell’s overarching policy is to avoid barrel contact. 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. 

A large oil spill is the only relevant accident IPF. A small fuel spill would not have 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 BOEM requirements and lease stipulations to avoid impacts on 

uses of the area by military vessels and aircraft. 

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 EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on other marine uses are expected. 

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. Prior to the lease sales, MMS prepared a multi-sale 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 exploration activities similar to those planned in this 

EP in several documents. The level and types of activities planned in Shell's 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 (MMS, 2007b), as updated by a 2012 Final EIS for Gulf of Mexico OCS Oil and Gas Lease 

Sales 2012-2017 (BOEM, 2012b), the Final Supplemental EIS for Gulf of Mexico Lease Sale OCS Oil 

and Gas Sale: 2012 (BOEM, 2012c), and the Final Supplemental EIS for Gulf of Mexico OCS Oil and 

Gas Lease Sales 2013-2014 (BOEM, 2013). 

Past, present, and reasonably foreseeable activities were identified in the cumulative effects scenario 

of these documents, which are incorporated by reference. The proposed action will not result in any 

Page 149 Public Information Copy
additional impacts beyond those evaluated in the multi-sale and Final EISs (MMS, 2007b; BOEM, 

2012b,c, 2013). 

Description of Activities Reasonably Expected to Occur in the Vicinity of Project Area. Other 

exploration and development activities may occur in the vicinity of lease block MC 943. Shell does not 

anticipate other projects in the vicinity of the project area beyond the types of projects analyzed in the 

lease sale and Supplemental EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b,c, 2013). 

Cumulative Impacts of Activities in the EP. The MMS (2007b) lease-sale EIS and BOEM (2012b,c, 

2013) Final EISs 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 (see MMS, 2007b; BOEM, 2012b). 

The EISs considered exploration, delineation, and development wells; platform installation; 

service-vessel trips; and oil spills. The EISs 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 EP are within the range of activities described and 

evaluated in the recent 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 EP, in conjunction with the other reasonably foreseeable activities expected to occur in 

the Gulf of Mexico. Thus, for all 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 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 BOEM 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 NAAQS (MMS, 2007b; 

BOEM, 2012b,c, 2013). In addition, the cumulative contribution to visibility impairment is also very 

small (MMS, 2007b; BOEM, 2012b,c, 2013). As mentioned in previous sections, projected emissions 

meet the BOEM exemption criteria and would not contribute to cumulative impacts on air quality. 

Climate Change. CO2 and CH4 emissions from the project would constitute a negligible contribution to 

greenhouse gas emissions from all OCS activities. According to BOEM (2013), greenhouse gas 

emissions from all OCS oil and gas activities make up a very small portion of national CO2 emissions 

and BOEM does not believe that emissions directly attributable to OCS activities are a significant 

contributor to global greenhouse gas levels. Greenhouse gas emissions identified in the 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 previous EISs. Globally, Shell is taking action in four areas: producing more natural 

gas, the cleanest burning fossil fuel; helping to develop technologies to capture and store CO2; 

producing low-carbon biofuel; and working to improve the energy efficiency of our operations (Shell, 

2012). 

Water Quality. Shell’s project will result in some minor water quality impacts due to the 

NPDES-permitted discharge of SBM 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 drilling rig), and temporary (lasting only hours longer than the disturbance or 

discharge). Any cumulative effects to water quality are expected to be negligible. 

Archaeological Resources. MC 943 is on the list of archaeology survey blocks (BOEM, 2012d). 

A geologic, stratigraphic, and archaeological assessment by GEMS (2013) and C&C (2007) identified 

no sonar contacts suggestive of significant submerged cultural or archeological resources. Also, the 

lease area is well beyond the 60-m (197-ft) depth contour used by the BOEM 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. 

Page 150 Public Information Copy
New Information. New information included in the most recent Programmatic, Supplemental, and 

Final EISs (BOEM, 2012a,b,d) has been incorporated into the EIA, where applicable. 

C.9.2 Cumulative Impacts to Biological Resources 

The work planned in this 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. White et al. (2012a,b) observed dead 

and damaged deepwater corals approximately 7 miles (11 km) southwest of the Macondo wellhead. 

The researchers concluded, based on hopanoid petroleum biomarker analysis of the flocculent 

material, that it contained oil from the Macondo spill. The impacted corals are located approximately 

55 miles (89 km) northeast of MC 943, in deeper water (4,600 ft [1,400 m]) than is found at the 

proposed wellsites (4,211 to 4,276 ft [1,284 to 1,303 m]). It is unlikely that there would be 

cumulative impacts to those corals even in the unlikely event of a large spill associated with the 

activities discussed in this EIA. 

Areas that may support high-density deepwater benthic communities will be avoided 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; BOEM, 2012b,c, 2013). 

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 drilling rig 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 BOEM-required mitigation measures, including 

NTLs 2012-BSEE-G01 and 2012-JOINT-G01. No significant cumulative impacts are expected. 

Coastal and Marine Birds. Birds 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 2012-BSEE-G01 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, timing, and geographic extent of drilling activities, collisions or other adverse 

effects are unlikely, and no significant cumulative impacts are expected. 

Fisheries Resources. Exploration and production structures occur in the vicinity of the lease area. The 

additional effect of the proposed drilling activity would be negligible. 

Coastal Habitats. Due to the distance of the wellsites 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 refuge or wilderness areas. Support 

operations, including the crew boat 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. New information included in the most recent Programmatic, Supplemental, and 

Final EISs (BOEM, 2012a,b,c) has been incorporated into the EIA, where applicable. 

C.9.3 Cumulative Impacts to Socioeconomic Resources 

The work planned in this EP is limited in geographic scope and duration, and the impacts on 

socioeconomic resources will be correspondingly limited. 

The multi-lease-sale and Supplemental and Final 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; 

Page 151 Public Information Copy
BOEM, 2012b,c, 2013). BOEM 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 

impacts in parts of Texas, and substantial impacts 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. New information included in the most recent Programmatic, Supplemental, and 

Final EISs (BOEM, 2012a,b,c, 2013) has been incorporated into the EIA, where applicable. 

D. ENVIRONMENTAL HAZARDS 

D.1 Geologic Hazards 

The shallow hazards assessment included in this EP concludes that the wellsites are suitable for the 

planned activities. Proposed wellsites A, B, C, and D are located 950, 1,300, 1,750, and 825 ft (290, 

396, 533, and 251 m), respectively, from the nearest seafloor faults (GEMS, 2013). No fault 

penetration is expected at any of the proposed wellsites. Based on results of a high-resolution 

geophysical survey consisting of frequency-enhanced three-dimensional seismic, subbottom profiling, 

(AUV) surveys, multibeam bathymetry, and side-scan sonar, these locations appear suitable for the 

planned activities (GEMS, 2013). 

See 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 drilling rig. 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 for safety reasons until the storm or weather event passes. In the 

event of a hurricane, procedures in Shell’s Hurricane Evacuation Plan would be followed.

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 (caused by Loop Current 

eddies and intrusions) and large waves were considered in the design criteria for the drilling rig. 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 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. 

Page 152 Public Information Copy
F. MITIGATION MEASURES 

The proposed action includes numerous mitigation measures required by laws, regulations, and BOEM 

lease stipulations and NTLs. The project will comply with applicable federal, state, and local 

requirements concerning air pollutant emissions, discharges to water, and solid waste disposal. 

Project activities will be conducted under Shell’s OSRP and will include the measures described in 

EP Section 2f. 

G. CONSULTATION 

No persons or agencies were consulted regarding potential impacts associated with the proposed 

activities during the preparation of this EIA. 

H. PREPARERS 

This EIA was prepared at the direction of Shell Offshore Inc. by its contractor, CSA Ocean Sciences Inc. 

Contributors included the following: 

 Tracy Albert (Regulatory Specialist, Regulatory Compliance Consultants of LA, LLC); 

 Jeffrey McMenis (Environmental Engineer, Shell Exploration & Production Co.); 

 John Baird (Reservoir Engineer, Shell Exploration & Production Co.); 

 Megan Henley (Drilling Engineer, Shell International Exploration and Production);

 Saurabh Jain (Well Engineer, Shell International Exploration and Production); 

 Phil Weatherill (Geologist, Shell Exploration & Production Co.); 

 June Mire, Ph.D. (Senior Ecologist and Project Manager, Tetra Tech, Inc.); 

 Neal Phillips, Ph.D. (Senior Scientist, CSA Ocean Sciences Inc.); 

 Cindy Chandool, Ph.D. (Senior Scientist, CSA Ocean Sciences Inc.); 

 Deborah Fawcett (Project Scientist III, CSA Ocean Sciences Inc.); 

 Keith VanGraafeiland (GIS/Remote Sensing Specialist, CSA Ocean Sciences Inc.); and 

 Kim Dunleavy (Senior Technical Editor, CSA Ocean Sciences Inc.).

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Wilson, J. 2003. Manatees in Louisiana. Louisiana Conservationist. July/August 2003, pp. 4-7. Accessed on 

March 5, 2014 at: http://lamer.lsu.edu/pdfs/Manatees_LaConservArticle.pdf. 

Witherington, B.E. 1997. The problem of photopollution for sea turtles and other nocturnal animals, pp. 303-328. In: 

J.R. Clemmons and R. Buchholz (eds.), Behavioral Approaches to Conservation in the Wild. Cambridge University 

Press, Cambridge, England. 

Würsig, B., S.K. Lynn, T.A. Jefferson, and K.D. Mullin. 1998. Behaviour of cetaceans in the northern Gulf of Mexico 

relative to survey ships and aircraft. Aquatic Mammals 24:41-50. 

Würsig, B., T.A. Jefferson, and D.J. Schmidly. 2000. The Marine Mammals of the Gulf of Mexico. Texas A&M University 

Press, College Station, TX. 232 pp. 

Page 161 Public Information Copy
SECTION 19: Administrative Information

A. Exempted Information Description (Public Information Copies Only) 

The following attachments are excluded from the public information copies of typical plans: 

1b. OCS Plan Information form – Bottom hole location & 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 

3g. High-Resolution Seismic Line & Top Hole Prog 

3h. & 3i. Stratigraphic Column with Time vs. depth table 

 

B. Bibliography 

 Geoscience Earth and Marine Services, Inc. (GEMS), Geologic, Stratigraphic and Archaeological 

Assessment of Blocks 942 (OCS G-24130), 943 (OCS G-34467), and Portions of Surrounding 

Blocks, Mississippi Canyon Area, Gulf of Mexico. Project No. 0513-2243a,b, dated February 11, 

2014. 

 C&C Technologies, Archaeological Assessment Report, Blocks 895-898, 939-942, & 983-986, 

Mississippi Canyon Area. Project No. 072657-072954, dated October, 2007. Data: AUV Side Scan 

Sonar and Sub-Bottom Profiler 

 Shell Regional OSRP 

 Environmental Impact Assessment, CSA March 2014 

Page 162 Public Information Copy