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-09670

Type - Initial Exploration Plan

Lease(s) - OCS-G33170 Block - 720 Mississippi Canyon Area

OCS-G33171 Block - 721 Mississippi Canyon Area

OCS-G33172 Block - 722 Mississippi Canyon Area

Operator - Shell Offshore Inc.

Drill & TA Wells A thru H

DP SEMISUBMERSIBLE

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.

Ronald O'Connor

Plan Coordinator

Description -

Rig Type -

Subject:

From:

November 28, 2012
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

Public Information Copy

November 1, 2012 

Ms. Liz Peuler, Section Chief 

Bureau of Ocean Energy Management 

1201 Elmwood Park Boulevard 

New Orleans, LA 70123-2394 

 

Attn: Plans Group GM 1053C 

SUBJECT: Initial Exploration Plan 

 OCS-G 33170, 33171 & 33172 

 Mississippi Canyon Blocks 720, 721 & 722 

 Offshore Louisiana 

Dear Ms. Peuler: 

 

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 to drill Well Locations A, B, C, D, E, F, 

G & H. Operations are targeted to commence in April 2013. 

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 Copies of this submittal. The cost recovery fee receipt of $27,536.00 is attached to the Proprietary 

copy of the Plan. 

We are also providing a copy of the Shallow Hazards Report, prepared by Gems, Inc. (Project No. 0909-1691b) of the 

shallow drilling hazards “Geologic and Stratigraphic Assessment of Blocks 720 (OCS-G 33170), 721 (OCS-G 33171) 

and 722 (OCS-G 33172) Mississippi Canyon Area, Gulf of Mexico” dated February 4, 2010 and the Archaeological 

Report prepared by C&C Technologies, dated December 2009; Project No. 097403-097494 covering Mississippi 

Canyon Blocks 676-678, 720-722 & 764-766. 

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 

OCS-G 33170, Mississippi Canyon Block 720

OCS-G 33171, Mississippi Canyon Block 721 

OCS-G 33172, Mississippi Canyon Block 722 

PUBLIC INFORMATION COPY 

NOVEMBER 1, 2012

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

Page 3 Public Information Copy
INITIAL EXPLORATION PLAN 

OCS-G 33170, Mississippi Canyon Block 720 

OCS-G 33171, Mississippi Canyon Block 721 

OCS-G 33172, Mississippi Canyon Block 722 

OFFSHORE LOUISIANA 

TABLE OF CONTENTS

SECTION 1 PLAN CONTENTS 

SECTION 2 GENERAL INFORMATION 

SECTION 3 GEOLOGICAL AND GEOPHYSICAL INFORMATION 

SECTION 4 HYDROGEN SULFIDE - H2S INFORMATION 

SECTION 5 MINERAL RESOURCE CONSERVATION INFORMATION

SECTION 6 BIOLOGICAL, PHYSICAL AND SOCIOECONOMIC 

 INFORMATION 

SECTION 7 WASTE AND DISCHARGE INFORMATION 

SECTION 8 AIR EMISSIONS INFORMATION 

SECTION 9 OIL SPILLS INFORMATION 

SECTION 10 ENVIRONMENTAL MONITORING INFORMATION 

SECTION 11 LEASE STIPULATIONS INFORMATION 

SECTION 12 ENVIRONMENTAL MITIGATION MEASURES INFORMATION 

SECTION 13 RELATED FACILITIES AND OPERATIONS INFORMATION 

SECTION 14 SUPPORT VESSELS AND AIRCRAFT INFORMATION 

SECTION 15 ONSHORE SUPPORT FACILITIES INFORMATION 

SECTION 16 SULPHUR OPERATIONS INFORMATION 

SECTION 17 COASTAL ZONE MANAGEMENT ACT (CZMA) INFORMATION 

SECTION 18 ENVIRONMENTAL IMPACT ANALYSIS (EIA) 

SECTION 19 ADMINISTRATIVE INFORMATION 

 

 

 

Page 4 Public Information Copy
Acronyms and Abbreviations 

DIOS Automated Data Inquiry for Oil Spills 

APD Application for Permit to Drill 

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/day) 

BSEE Bureau of Safety and Environmental 

Enforcement 

CFR Code of Federal Regulations 

CH4 methane 

CO carbon monoxide 

CO2 carbon dioxide 

DPS distinct population segment 

EA Environmental Assessment 

EFH Essential Fish Habitat 

EIA Environmental Impact Analysis 

EIS Environmental Impact Statement 

EP Exploration Plan 

ESA Endangered Species Act 

FAD fish-attracting device 

g C m-2 grams of carbon per square meter 

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 

NA Natural Area 

NAAQS National Ambient Air Quality Standards 

NEPA National Environmental Policy Act 

NMFS National Marine Fisheries Service 

NOAA National Oceanic and Atmospheric 

Administration 

NO2 nitrogen dioxide 

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 hydrocarbon 

PM particulate matter 

PSD Prevention of Significant Deterioration 

ROV remotely operated vehicle 

SBM synthetic-based mud 

SEA Site-Specific Environmental Assessment 

Shell Shell Offshore Inc. 

SO2 sulfur dioxide 

SOx sulfur oxides 

SP State Park 

SWIM Service Water and Impoundment 

Monitoring 

SWSS Sperm Whale Seismic Study 

U.S.C. United States Code 

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 

Page 5 Public Information Copy
SECTION 1: PLAN CONTENTS

A. DESCRIPTION, OBJECTIVES & SCHEDULE

Shell Offshore Inc. (Shell) is submitting an initial exploration plan (EP/plan) for Mississippi Canyon (MC) Blocks 720, 

721 and 722, OCS-G 33170, 33171 and 33172 respectively. This plan includes eight proposed exploration wells: A, 

B, C, D, E, F, G & H. The wells will be drilled and temporarily abandoned with cement plugs and corrosion caps in 

accordance with 30 CFR 250.1721 until the wells are completed and developed under future plans. If the wells are 

unsuccessful, they will be permanently plugged and abandoned in accordance with the Bureau of Safety and 

Environmental Enforcement (BSEE) regulations. 

The drilling activities are planned to commence on or about April 2013 and last approximately 165 days per well. The 

timeframe to complete the initial drilling activities is an estimate based on the best available information regarding 

downhole conditions likely to be encountered while drilling each well and are not intended to be a limitation. 

The lease area is 49 statute miles from the nearest shoreline, 108 statute miles from the onshore support base at 

Port Fourchon, Louisiana and 74 statute miles from the helicopter base at Boothville, Louisiana. Water depths at 

the well sites range from 3,125’ to 3,747’ (Attachment 1A). 

The proposed rig is a dynamically positioned (DP) semi-submersible; a self-contained drilling vessel with 

accommodations for a crew which include quarters, galley and sanitation facilities. The rig will comply with the 

requirements in the Interim Final Rules. The drilling activities will be supported by the support vessels and aircraft as 

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

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

purchasing to the maximum extent possible. Shell personnel and contractors are experienced at operating in the Gulf 

of Mexico and are well versed in all Federal and State laws regulating operations. Shell’s employees and contractors 

share Shell’s deep commitment to operating in a safe and environmentally responsible manner.

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

of Mexico. Shell will draw upon this experience in organizing and carrying out its planned MC 720/721/722 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 Oil Spill Response Plan (OSRP) is designed to contain and respond to a spill that meets or 

exceeds the worst case discharge (WCD) as 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. 

We continue to invest in research and development 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 location plat (Attachments 1A) and BOEM forms (Attachments 1B through 1J). 

C. RIG SAFETY AND POLLUTION FEATURES 

The rig (Noble Jim Day or similar) will comply with all of the regulations of the American Bureau of Shipping (ABS), 

International Maritime Organization (IMO) and the United States Coast Guard (USCG). All drilling operations will be 

conducted under the provisions of 30 CFR, Part 250, Subpart D and other applicable regulations and notices, 

including those regarding the avoidance of potential drilling hazards and safety and pollution prevention control. 

Such measures as inflow detection and well control, monitoring for loss of circulation and seepage loss and casing 

design will be our primary safety measures. Primary pollution prevention measures are contaminated and noncontaminated drain system, mud drain system and oily water processing. 

DRAIN SYSTEM POLLUTION FEATURES 

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

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

plate to prevent debris from entering the system. 

Page 6 Public Information Copy
Deck drainage from rainfall, rig washing, deck washing and runoff from curbs and gutters, including drip pans and 

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

the Rig. 

1) Non-contaminated Drains

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

and can be discharged directly overboard. These are mostly located around the main deck and outboard in places 

where it is unlikely that hydrocarbons will be found. 

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

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

“normally open” to allow run-off of rain water. Normally open drains shall have a plug located in a conspicuous area 

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

The rig’s drain plug program 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 have to 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 overboard. 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. 

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 be pump out with the bilge pump 

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

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

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

high and low levels. 

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

used for emergency bilge pumps 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. 

Page 7 Public Information Copy
– Portable submersible pumps 

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

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

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

water out in order to keep flooding under control. The pumps are also capable of being put in manual mode in which 

they can be turned on by hand. 

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. 

9) 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. 

10) 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. 

11) 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 

Page 8 Public Information Copy
12) 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 pumped

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. 

D. Storage Tanks – Noble Jim Day or similar:

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)

Diesel Day Tank Drilling Rig 100 1 Marine Diesel (0.91 SG)

Diesel Day Tank Drilling Rig 115 1 Marine Diesel (0.91 SG)

Diesel Day Tank Drilling Rig 114 1 Marine Diesel (0.91 SG)

Diesel Day Tank Drilling Rig 115 1 Marine Diesel (0.91 SG)

Total engine room diesel Drilling Rig 970 Marine Diesel (0.91 SG)

Lube Oil Tank Drilling Rig 86.25 4 345 Lube Oil (0.91 SG)

Page 9 Public Information Copy
E. Pollution Prevention Measures 

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

the discharges of oils and greases from the rig during rainfall or routine operations. Nevertheless, Shell has provided 

this information as part of its response to 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. 

G. Description of Previously Approved Lease Activities

Shell has no previously approved well locations in Mississippi Canyon 720, 721 and 722. 

Page 10 Public Information Copy
Attachment 1A 

Bathymetry and Surface Locations 

 

Page 11 Public Information Copy
Attachment 1B 

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) 728-4652

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

Lease(s): G 33170, 33171, 33172 Area: MC Block(s): 720, 721, 

722

Project Name (If Applicable): Queen

Objective(s): X Oil Gas Sulphur Salt Onshore Base: Fouchon Distance to Closest Land (Miles): 49

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 an BOEM-designated high-probability archaeological area? X Yes 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 4/1/2013 9/13/2013 165

Drill and suspend Well B 4/1/2014 9/13/2014 165

Drill and suspend Well C 4/1/2015 9/13/2015 165

Drill and suspend Well D 4/1/2016 9/13/2016 165

Drill and suspend Well E 4/1/2017 9/13/2017 165

Drill and suspend Well F 4/1/2018 9/13/2018 165

Drill and suspend Well G 4/1/2019 9/13/2019 165

Drill and suspend Well H 4/1/2020 9/13/2020 165

Description of Drilling Rig Description of Production Platform

Jackup 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 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 1C 

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 Yes X No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 33171

Area Name Mississippi Canyon

Block No. 721

Blockline

Departures

(in feet)

N/S Departure: 4,024 FSL

E/W Departure: 5,957 FEL

Lambert X-Y 

coordinates

X: 960,283

Y: 10,252,504

Latitude/

Longitude

Latitude 28.23588769

Longitude -89.11273115

TVD (Feet): MD (Feet): Water Depth (Feet): 3,747’

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 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): B Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 33171

Area Name Mississippi Canyon

Block No. 721

Blockline

Departures

(in feet)

N/S Departure: 2,120’ FSL

E/W Departure: 4,840’ FEL

Lambert X-Y 

coordinates

X: 961,400

Y: 10,250,600

Latitude/

Longitude

Latitude 28.23070670

Longitude -89.10916125

TVD (Feet): MD (Feet): Water Depth (Feet): 3,691’

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 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): C Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 33171

Area Name Mississippi Canyon

Block No. 721

Blockline

Departures

(in feet)

N/S Departure: 1,072 FSL

E/W Departure: 7,746 FEL

Lambert X-Y 

coordinates

X: 958,494

Y: 10,249,552

Latitude/

Longitude

Latitude 28.22768556

Longitude -89.11812591

TVD (Feet): MD (Feet): Water Depth (Feet): 3,713’

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 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): D Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 33171

Area Name Mississippi Canyon

Block No. 721

Blockline

Departures

(in feet)

N/S Departure: 1,865 FSL

E/W Departure: 8,873 FEL

Lambert X-Y 

coordinates

X: 957,367

Y: 10,250,345

Latitude/

Longitude

Latitude 28.22981070

Longitude -89.1216640

TVD (Feet): MD (Feet): Water Depth (Feet): 3,688’

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
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): E Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 33170

Area Name Mississippi Canyon

Block No. 720

Blockline

Departures

(in feet)

N/S Departure: 7,020’ FSL

E/W Departure: 3,540’ FWL

Lambert X-Y 

coordinates

X: 938,100

Y: 10,255,500

Latitude/

Longitude

Latitude 28.24304421

Longitude -89.18176764

TVD (Feet): MD (Feet): Water Depth (Feet): 3,255’

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 17 Public Information Copy
Attachment 1H

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): F Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 33170

Area Name Mississippi Canyon

Block No. 720

Blockline

Departures

(in feet)

N/S Departure: 2,420’ FSL

E/W Departure: 3,140’ FWL

Lambert X-Y 

coordinates

X: 937,700

Y: 10,250,900

Latitude/

Longitude

Latitude 28.23037652

Longitude -89.18275197

TVD (Feet): MD (Feet): Water Depth (Feet): 3,190’

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 18 Public Information Copy
Attachment 1I 

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): G Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 33170

Area Name Mississippi Canyon

Block No. 720

Blockline

Departures

(in feet)

N/S Departure: 4,960’ FNL

E/W Departure: 1,500’ FWL

Lambert X-Y 

coordinates

X: 936,060

Y: 10,259,360

Latitude/

Longitude

Latitude 28.25355608

Longitude -89.18831792

TVD (Feet): MD (Feet): Water Depth (Feet): 3,125’

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 19 Public Information Copy
Attachment 1J 

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): H Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 33172

Area Name Mississippi Canyon

Block No. 722

Blockline

Departures

(in feet)

N/S Departure: 317’ FSL

E/W Departure: 1,380’ FWL

Lambert X-Y 

coordinates

X: 967,620

Y: 10,248,797

Latitude/

Longitude

Latitude 28.22604445

Longitude 89.08975587

TVD (Feet): MD (Feet): Water Depth (Feet): 3,734’

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

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-Bonding; NTL No. 2000-G16, “Guideline for General Lease 

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

G. Oil Spill Financial Responsibility (OSFR)

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

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

Spill Financial Responsibility for Covered Facilities.”

H. Deepwater well control statement

Shell Offshore Inc., BOEM Operator Number 0689, has the financial capability to drill a relief well and conduct other 

emergency well control operations if required. 

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 21 Public Information Copy
J. Blowout scenario 

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 research and development (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 721 Well D 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 (updated in July 2012) is based on MC-391 Well D (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) 392,000 bbl 

Uncontrolled blowout rate (first 30-days average daily rate) 355,000 bopd 

Duration of flow (days) based on relief well 157 days

Total volume of spill (bbls) for 157 days 52 MMBO

Table 2.1. Queen Worst Case Discharge Summary 

The exploration prospect is located approximately 49 statute miles south-southeast of the nearest Louisiana 

shoreline in the Gulf of Mexico, in water depths of 3,125-3,747’ across the prospect. The structural component of the 

prospect is defined by an embayment culmination against base salt. The objective interval for the proposed well with 

flow potential is in The Miocene section, and the MC 721 D well is expected to have the highest flow rates. The 

alternate well locations (A, B, C, E, F, G, and H) were also evaluated; however, their flow rates are lower than the 

WCD calculated for the MC 721 D 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. 

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. 

Page 22 Public Information Copy
3) Information Requirements 

a) Blowout scenario 

All well locations addressed in this EP were assessed for WCD. The MC 721 well from the D location represents the 

highest flow potential. The D 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-721

Facility Designation MODU 

Distance to Nearest Shoreline (Statute miles) 49

Uncontrolled blowout (volume first day) 392,000 bbl 

Uncontrolled blowout rate (first 30-days average daily rate) 355,000 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) 157 days total duration to drill relief well 

(14 days rig demobilization, 3 days rig mobilization, 78 days spud to 

TD, 30 days ranging, 32 days contingency). 

Total volume of spill (bbls) 52 MMBO based on 157 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. 

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 in-situ 

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. 

Page 23 Public Information Copy
f) Likelihood for intervention to stop the blowout. 

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

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

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

making blowouts extremely rare events. 

Intervention Devices: Notwithstanding these facts, the main scenario for recovery from a blowout event is via 

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

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

GOM will have redundancies meeting the Interim Final Drilling Safety Rule with respect to Remotely Operated 

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

Additionally the Noble Jim Day (dynamically positioned semisubmersible) has a gas handler system at the top of the 

riser consisting of two annular preventers that can be closed in to allow hydrocarbons in the riser to be contained or 

circulated thru the rig’s well control system. The rig has two shearing rams in the BOP for added redundancy. Also, 

the Noble Jim Day is equipped with a deadman system and an auto shear system. 

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 2012 – 2015 timeframe. The dynamically positioned rigs under contract, the Noble Danny Adkins, 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. Shell’s current 

contracted rigs capable of operating at Queen water depths and reservoir depths without constraints are in the 

following table: 

Rig Name Rig Type

Noble Danny Adkins 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 Queen 

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 Queen. 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 3 days 

transit to mobilize to the relief well site depending on distance to the site. The relief well will take approximately 78 

days to drill down to the last casing string above the blowout zone, plus approximately 30 days for precision ranging 

Page 24 Public Information Copy
activity to intersect the blowout well bore. Additionally, 32 extra days of contingency are added. The total time to 

mobilize and drill a relief well would be 157 days for the Queen wells. 

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 three deepwater anchor handlers, the Laney, Dino, and Ross 

Chouest, 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 un-defined or 

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

design and operations on the well. 

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

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

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

identify the risks in drilling operations and align plans to mitigate those risks; an alignment which is critical before 

drilling begins. 

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

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

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

board. Shell’s involvement in global deepwater drilling, starting in the GOM in the mid-1980’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 Queen. 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. 

Page 25 Public Information Copy
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, 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 3f of this document, Shell is currently analyzing recent advances in containment technology and 

equipment and will incorporate them as they become available. 

k) Arrangements for drilling a relief well 

The size of the Shell contracted rig fleet in the GOM from 2012-2015 ensures that there is adequate well equipment 

(e.g. casing and wellhead) available for relief wells. Rigs and personnel will also be readily available within Shell, 

diverted from their active roles elsewhere. Resources from other operators can also be leveraged should the need 

arise. Generally, relief well plans will mirror the blowout well, incorporating any learning on well design based on 

root cause analysis of the blowout. A generic relief well description is outlined in the WCCP. 

l) Assumptions and calculations used in approved or proposed Regional OSRP 

All proposed Queen locations were evaluated and Location D 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 26 Public Information Copy
SECTION 3: GEOLOGICAL AND GEOPHYSICAL INFORMATION

A. Geological description

Proprietary data 

B. Structure Contour Map(s)

Proprietary data 

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

Proprietary data 

D. Geological Structure Cross-section(s)

Proprietary data 

E. Stratigraphic Column with Time vs Depth Table

Proprietary data

F. Shallow Hazards Report

The following report was used for our analysis: 

The Shallow Hazards Report, prepared by Gems, Inc. (Project No. 0909-1691b) of the shallow drilling 

hazards “Geologic and Stratigraphic Assessment of Blocks 720 (OCS-G 33170), 721 (OCS-G 33171) and 722 

(OCS-G 33172) Mississippi Canyon Area, Gulf of Mexico” dated February 4, 2010. 

The Archaeological Report prepared by C&C Technologies, dated December 2009; Project No. 097403-

097494 covering Mississippi Canyon Blocks 676-678, 720-722 & 764-766. 

G. Shallow Hazards Assessment

See Section 6A of this plan for detailed site assessment. 

H. Geochemical Information

This information is not required for plans submitted in the GOM Region. 

I. Future G&G Activities

This information is not required for plans submitted in the GOM Region. 

Page 27 Public Information Copy
SECTION 4: HYDROGEN SULFIDE (H2S) 

 Concentration 

0 ppm

 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. 

 H2S Contingency Plan

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

proposed exploration activities. 

 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 28 Public Information Copy
SECTION 5: MINERAL RESOURCE CONSERVATION INFORMATION

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

the case of DOCDs. 

Page 29 Public Information Copy
SECTION 6: BIOLOGICAL, PHYSICAL AND SOCIOECONOMIC INFORMATION

A. Chemosynthetic Communities Report

Shallow Hazards Reports and Data: 

Geoscience Earth and Marine Services, Inc, Geologic and Stratigraphic Assessment of Blocks 720 (OCS-G 

33170), 721 (OCS-G 33171), and 722 (OCS-G 33172), Mississippi Canyon Area, Gulf of Mexico, Project # 

0609-1691b, dated February 4, 2010. AUV side-scan sonar and sub-bottom profiler, and Reprocessed 3-D 

seismic data. 

Locations are Mississippi Canyon Blocks 720, Proposed Locations E, F and G, Mississippi Canyon 721, 

Proposed Locations A, B, C and D, and Mississippi Canyon 722, Proposed Location H. Proposed Locations A, 

C, D and H surface locations have been revised from the shallow hazards report. 

Archaeological Reports: 

C&C Technologies, Archaeological Assessment Report, Blocks 676-678, 720-722, 765-766, and Vicinity, 

Mississippi Canyon Area, Project No. 097403-097494, December, 2009. AUV side-scan sonar and sub-bottom 

profiler data. 

C&C Technologies, Archaeological and Hazard Report, Blocks 808, 809, 852, 853 and Vicinity, Mississippi 

Canyon Area, Project No. 083986-084109, February, 2009. AUV side-scan sonar and sub-bottom profiler 

data. 

C&C Technologies, Archaeological Assessment Report, Block 854 and Vicinity (Blocks 809-811, 853, 855, 897-

899), Mississippi Canyon Area, Project No. 072879-072915, August 2007. AUV side-scan sonar and subbottom profiler data. 

Proposed Locations and Coordinates: 

Proposed Location / 

Block X coordinate Y coordinate FNL/FSL FEL/FWL

Water 

Depth

Prop Loc A / MC 721 960,283 10,252,504 4024’ FSL 5957’ FEL 3747’

Prop Loc B / MC 721 961,400 10,250,600 2120’ FSL 4840’ FEL 3691’

Prop Loc C / MC 721 958,494 10,249,552 1072’ FSL 7746’ FEL 3713'

Prop Loc D / MC 721 957,367 10,250,345 1865’ FSL 8872’ FEL 3688’

Prop Loc E / MC 720 938,100 10,255,500 7020’ FSL 3540’ FWL 3255’

Prop Loc F / MC 720 937,700 10,250,900 2420’ FSL 3140’ FWL 3190’

Prop Loc G / MC 720 936,060 10,259,360 4960’ FNL 1500’ FWL 3125’

Prop Loc H / MC 722 967,620 10,248,797 317’ FSL 1380’ FWL 3734’

Coordinates are in UTM 316, NAD27 

See Attachments 6A through 6H for Enhanced Seafloor Rendering Maps. 

Site Assessment MC 721, Proposed Location A: 

Mississippi Canyon 721, Proposed Location A is located in a water depth of approximately 3,747 feet. A 

major seafloor fault is identified over 1000’ east southeast of proposed location, associated with a seafloor 

graben area. Hummocky topography is identified 500’ north of proposed location. 

Page 30 Public Information Copy
The stratigraphy at the site of MC 721, Proposed Location A consists of: 

• Unit 1 (Seafloor – 662’ BML) –15’ of drape over chaotic mass-transport deposits (MTDs), 647’ of 

alternating intervals of bedded clays and chaotic mass-transport deposits (MTDs). 

• Unit 2 (662’ – 1,387’ BML) –227’ of bedded hemipelagic muds and chaotic mud-rich MTDs, 203’

of mud-rich MTDs, 295’ of MTD’s with sand seams and pockets. A fault will be penetrated 1,335’ 

BML. 

• Unit 3 – Blue Unit (1,387’ – 2,566’ BML) –1,179’ of basin floor fan that is sand-rich with 

discontinuous moderate to high amplitude reflectors. A fault will be penetrated 1,855’ below the 

mud line. 

• Unit 4 (2566’ – 3456’ BML) –890’ of mud-rich turbidites and MTDs. 

• Unit 5 (3456’ – 4504’ BML) –259’ of mud-rich turbidites, 335’ of moderate amplitude, leveeoverbank thin sands, and 454’ of mud-rich MTDs. A fault will be penetrated 4,499’ below the 

mud line. 

Faults will be penetrated 1,335’, 1,855’ and 4,499’ below the mud line. The casing program is designed for 

fault penetration. 

Shallow Water Flow Potential: 

 Negligible Potential - Seafloor to 889’ BML

 Low Potential – 889’ to 1,387’ BML

 High Potential – 1,387’ to 2,566’ BML

 Low Potential – 2,566’ to 3,715’ BML

 Moderate Potential – 3,715’ to 4,050’ BML

 Low Potential – 4,050’ to 4,504’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor to 1,092’ BML

 Low Potential – 1,092’ to 4,504’ BML

High amplitudes are identified 500’ north northwest and 500’ south southeast in Unit 3 (1,442’ – 2,618’ BML)

and this proposed location will not penetrate any high amplitudes. 

Benthic/Anchor Assessment, MC 721, Proposed Location A (no anchors – DP Vessel) 

Mississippi Canyon 721, Proposed Location A is located in a water depth of approximately 3,747’. Hummocky 

topography is identified 500 feet north of Proposed Location A. 

A major seafloor fault is identified over 1,000’ east southeast of location, associated with a seafloor graben 

area. There is no other evidence of seafloor or near-surface faulting, slumping, amplitudes or fluid expulsion 

features within 2,000’ of location. This location will not disturb any high-density areas of benthic 

communities. 

There are no marine avoidance areas identified within 2,000’ of this location, and there are no existing 

surface locations or flowlines within 2,000’ of this area. 

Conclusion: 

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 721, Proposed Location A appears suitable for the planned activity. 

Page 31 Public Information Copy
Site Assessment, MC 721, Proposed Location B: 

Mississippi Canyon 721, Proposed Location B is located in a water depth of approximately 3,691’. One major 

seafloor fault is identified 375’ west and another is 3,000’ east of proposed location; both are associated with 

a seafloor graben area. A narrow seafloor furrow is identified 1,800’ east of location. 

The stratigraphy at the site of MC 721, Proposed Location B consists of: 

 Unit 1 (Seafloor - 614' BML) – 21’ of drape over 593’ of alternating intervals of bedded clays and 

chaotic mass transport deposits (MTDs). 

 Unit 2 (614' – 1,442' BML) – 197’ of bedded hemipelagic muds and chaotic mud-rich MTDs, and 631’

of discontinuous to chaotic MTDs with mud-rich, thin sands near the base. 

 Unit 3 - Blue Unit (1,442' – 2,618' BML) – 1,176’ of basin floor fan that is sand-rich with 

discontinuous moderate to high amplitude reflectors. 

 Unit 4 (2,618' – 3,318' BML) – 700’ of mud-rich turbidites and MTDs with possible thin sand seams. 

 Unit 5 (3,318' – 3,896' BML) – 578’ of mud-rich turbidites, moderate amplitudes, levee over-bank 

deposits with thin and sand mud-rich MTDs. A fault will be penetrated 3,462’ below the mud line.

A fault will be penetrated 3,462’ below the mud line. The casing program is designed for fault penetration. 

Shallow Water Flow Potential: 

 Negligible Potential - Seafloor to 811' BML 

 Low Potential - 811' to 1,442' BML 

 High Potential – 1,442' to 2,618' BML 

 Low Potential - 2618' to 3,896' BML 

Shallow Gas Potential: 

 Negligible Potential - Seafloor to 1,442' BML 

 Moderate Potential – 1,442 to 1,964' BML 

 Low Potential – 1,964' to 3,896' BML 

High amplitudes are identified 400’ southeast of Proposed Location B, in Unit 3 and will not penetrate any 

high amplitudes or amplitude anomalies. 

Benthic/Anchor Assessment, MC 721, Proposed Location B (no anchors – DP Vessel) 

Mississippi Canyon 721, Proposed Location B is located in a water depth of approximately 3,691’. A narrow 

seafloor furrow is identified 1,800’ east of proposed location. 

One major seafloor fault is identified 375’ west and another is 3,000’ east of this location; both are associated 

with a seafloor graben area. There is no other evidence of seafloor or near-surface faulting, slumping, 

amplitudes or fluid expulsion features within 2,000’ of location and this location will not disturb any highdensity areas of benthic communities. 

There are no marine avoidance areas identified within 2,000’ of this location and there are no existing surface 

locations or flowlines within 2,000’ of this area. 

Conclusion: 

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 721, Proposed Location B appears suitable for the planned activity. 

Page 32 Public Information Copy
Site Assessment, MC 721, Proposed Location C: 

Mississippi Canyon 721, Proposed Location C is located in a water depth of approximately 3,713’. Hummocky 

topography is identified 400’ west of proposed location. A major seafloor fault is identified over 1,400’

southeast of this location, associated with a seafloor graben area. 

The stratigraphy at the site of MC 721, Proposed Location C consists of: 

• Unit 1 (Seafloor - 602' BML) – 26’ of drape over chaotic mass-transport deposits (MTD's), over 

576’ of alternating intervals of bedded clays and chaotic MTDs. 

• Unit 2 (602' – 1,444' BML) – 842’ of bedded hemipelagic muds and chaotic mud-rich MTDs. 

• Unit 3 - Blue Unit (1,444' – 2,427' BML) – 983’ of sand-rich interval of channel and overbank 

deposits. 

• Unit 4 (2,427' – 3,207' BML) – 780’ of mud-rich turbidites and MTDs with possible thin sand 

seams. 

• Unit 5 (3,207' – 4,706' BML) – 1499’ of mud-rich turbidites. A fault will be penetrated 3,818’

BML. 

A fault will be penetrated 3,818’ below the mud line. The casing program is designed for fault penetration. 

Shallow Water Flow Potential: 

 Negligible Potential - Seafloor to 602' BML 

 Low Potential - 602' to 1,444' BML 

 High Potential – 1,444' to 2,427' BML 

 Low Potential – 2,427' to 4,706' BML 

Shallow Gas Potential: 

 Negligible Potential - Seafloor to 1,444' BML 

 Low Potential – 1,444' to 4,706' BML 

High amplitude reflectors are identified 400’ northwest of this location in Unit 3 (1,444’ – 2,427’ BML) and 

300 feet southeast of this area in Unit 5 (3,207’ – 4,706’ BML) and this location will not penetrate any 

amplitude anomalies. 

Benthic/Anchor Assessment, MC 721, Proposed Location C (no anchors – DP Vessel) 

Mississippi Canyon 721, Proposed Location C is located in a water depth of approximately 3,713’. Hummocky 

topography is identified 400’ west of this location. 

A major seafloor fault is identified over 1,400’ southeast of this location, associated with a seafloor graben 

area. There is no other evidence of seafloor or near-surface faulting, slumping, amplitudes or fluid expulsion 

features within 2000’ of proposed location. This location will not disturb any high-density areas of benthic 

communities.

There are no marine avoidances areas identified within 2,000’ of this location. 

Currently, there are no existing surface locations or flowlines within 2,000’ of this location. 

Conclusion: 

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 721, Proposed Location C appears suitable for the planned activity. 

Page 33 Public Information Copy
Site Assessment, MC 721, Proposed Location D: 

Mississippi Canyon 721, Proposed Location D is located in a water depth of approximately 3,688’. Hummocky 

topography is identified 250’ south of proposed location, and a seafloor gully is identified 1,700’ east of 

location D. 

The stratigraphy at the site of MC 721, Proposed Location D consists of: 

• Unit 1 (Seafloor - 614' BML) - 22 feet of drape over 592 feet of alternating intervals of bedded 

clays and chaotic mass-transport deposits (MTDs). 

• Unit 2 (614' – 1,510' BML) - 457 feet of bedded hemipelagic muds and chaotic mud-rich MTDs 

and 439 feet of MTDs with sand seams and pockets. 

• Unit 3 - Blue Unit (1,510' – 2,517' BML) – 1,007’ of basin floor fan that is sand-rich with 

discontinuous moderate to high amplitude reflectors. 

• Unit 4 (2,517' – 3,375' BML) - 858 feet of mud-rich turbidites and MTDs. 

• Unit 5 (3,375' – 4,779' BML) – 1,403’ of mud-rich turbidites. A fault will be penetrated 4,441’

BML. 

A fault will be penetrated 4,441’ below the mud line. The casing program is designed for fault penetration. 

Shallow Water Flow Potential 

 Negligible Potential - Seafloor to 1,071' BML

 Low Potential – 1,071' to 1,510' BML 

 High Potential – 1,510' to 2,517' BML 

 Low Potential – 2,517 to 4,779' BML 

Shallow Gas Potential 

 Negligible Potential - Seafloor to 1,510' BML 

 Low Potential – 1,510' to 4,779' BML 

High amplitude reflectors are identified 500’ southwest and 500’ southeast of location in Unit 3 (1,510’ to 

2,517' BML) and this location will not penetrate any high amplitudes. 

Benthic/Anchor Assessment, MC 721, Proposed Location D (no anchors – DP Vessel) 

Mississippi Canyon 721, Proposed Location D is located in a water depth of approximately 3,688’. Hummocky 

topography is identified 250’ south of proposed location. A seafloor gully is identified 1,700’ east of location. 

There is no evidence of seafloor or near-surface faulting, slumping, amplitudes or fluid expulsion features 

within 2,000’ of proposed location. This location will not disturb any high-density areas of benthic 

communities. 

There are no marine avoidances areas identified within 2,000’ of this location. 

Currently, there are no existing surface locations or flowlines within 2,000’ of this location. 

 

Conclusion: 

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 721, Proposed Location D appears suitable for the planned activity. 

Page 34 Public Information Copy
Site Assessment, MC 720, Proposed Location E: 

Mississippi Canyon 720, Proposed Location E is located in a water depth approximately 3,255’. 

The stratigraphy at the site of MC 720, Proposed Location E consists of: 

 Unit 1 (Seafloor – 527’ BML) – 22’ of drape over chaotic mass-transport deposits (MTDs), 342’ of 

alternating intervals of bedded clays and chaotic MTDs, and 163’ of chaotic MTDs with possible thin 

sand seams and pockets. 

 Unit 2 (527’ – 2,006’ BML) – 242’ of mud-rich MTDs, 455’ of bedded mud-rich turbidites, and 945’ of 

basin floor fan that is sand-rich with discontinuous moderate to high amplitude reflectors. 

 Unit 3 Blue Unit (2,006’ – 3,018’ BML) – 1012’ of basin floor fan that is sand-rich with discontinuous 

moderate to high amplitude reflectors. 

 Unit 4 (3,018 – 3,778’ BML) – 760’ of mud-rich turbidities and MTDs, with possible thin sand seams. 

 Unit 5 (3,778’ – 5,969’ BML) – 1,297’ of discontinuous mud-rich turbidites with possible thin sand 

seams. 

Shallow Water Flow Potential 

 Negligible Potential – Seafloor to 364’ BML

 Low Potential – 364’ to 527’ BML

 Negligible Potential – 527’ to 1,224’ BML

 Moderate Potential – 1,224’ to 2,006’ BML

 High Potential – 2,006’ to 3,018’ BML

 Low Potential – 3,018’ to 5,969’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor to 1,224’ BML

 Low Potential – 1,224’ to 5,969’ BML

There are no high amplitude reflectors identified within 500 feet of Proposed Location E. 

Benthic/Anchor Assessment, MC 720, Proposed Location E (no anchors – DP Vessel) 

Mississippi Canyon 720, Proposed Location E is located in a water depth approximately 3,255 feet. 

There is no evidence of surface or near-surface faulting, slumping, amplitudes or fluid expulsion features 

within 2000’ of this location. The location will not disturb any high-density area of benthic communities. 

There are no marine avoidances identified within 2,000’ of location. 

Shell’s 18” oil flowline is identified 1,420’ east of this location. This flowline and the 500’ avoidance area 

associated with the flowline are within 2,000’ of this location. Currently, there are no other wells or flowlines 

identified within 2,000’ of location. 

Conclusion: 

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 720, Proposed Location E appears suitable for the planned activity. 

Page 35 Public Information Copy
Site Assessment, MC 720, Proposed Location F: 

Mississippi Canyon 720, Proposed Location F is located in a water depth of approximately 3,190’ and will be 

positioned 840’ upslope of the thalwag of an easterly trending valley.

The stratigraphy at the site of MC 720, Proposed Location E consists of: 

 Unit 1 (Seafloor – 575’ BML) – 15’ of drape over 325’ of alternating intervals of bedded silty clays and 

235’ of chaotic MTDs with possible thin sand seams and pockets. 

 Unit 2 (575’ – 2,217’ BML) – 665’ of bedded mud-rich MTDs, 339’ of discontinuous overbank deposits 

with mud-rich sand seams and pockets, and 638’ of levee overbank and canyon fill sediments that 

are mud-rich sediments with scattered sand seams and pockets 

 Unit 3 Blue Unit (2,217’ – 2,814’ BML) – 597’ of basin floor fan that is sand-rich with discontinuous 

moderate to high amplitude reflectors. 

 Unit 4 (2,814’ – 3,548’ BML) – 734’ of mud-rich turbidites and MTDs with possible thin sand seams. 

 Unit 5 (3,548’ – 5,231’ BML) – 801’ of discontinuous mud-rich MTDs and 882’ of mud-rich turbidites. 

Shallow Water Flow Potential 

 Negligible Potential – Seafloor to 340’ BML

 Low Potential – 340’ to 575’ BML

 Negligible Potential – 575’ to 1,240’ BML

 Low Potential – 1,240’ to 1,579’ BML

 Moderate Potential – 1,579’ – 2,217’ BML

 High Potential – 2,217’ to 2,814’ BML

 Low Potential – 2,814’ to 5,231’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor – 1,579’ BML

 Low Potential – 1,579’ to 5,231’ BML

There are no high amplitude reflectors identified within 500’ of proposed location. 

Benthic/Anchor Assessment, MC 720, Proposed Location F (no anchors – DP Vessel) 

Mississippi Canyon 720, Proposed Location F is located in a water depth of approximately 3,190’ and will be 

positioned 840’ upslope of the thalwag of an easterly trending valley.

There is no evidence of seafloor or near-surface faulting, slumping, amplitudes or fluid expulsion features 

within 2,000’ of this location. This location will not disturb any high-density areas of benthic communities. 

Three marine avoidances are identified within 2,000’ of Proposed Location F:

Avoidance 

Zone Number Avoidance Size X Coordinate Y Coordinate

Distance from 

Prop. Loc F

Direction from 

Prop Loc F

2,839 100’ 936,869 10,250,377 982’ West 

southwest

2,841 100’ 937,722 10,249,573 1,327’ South

5,620 50’ 935,997 10,250,360 1,786 West

Currently, there are no existing surface locations or flowlines within 2,000’ of proposed location. 

Page 36 Public Information Copy
Conclusion: 

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 720, Proposed Location F appears suitable for the planned activity. 

Site Assessment, MC 720, Proposed Location G: 

Mississippi Canyon 720, Proposed Location G is located in a water depth of approximately 3,125’. 

The stratigraphy at the site of MC 720, Proposed Location G consists of: 

 Unit 1 (Seafloor – 615’ BML) – 18’ of drape over 417’ of alternating intervals of bedded clays and 

chaotic mass-transport deposits (MTDs), and 180’ of mud-rich MTDs. 

 Unit 2 (615’ – 2,072’ BML) – 305’ of mud-rich MTDs, 280’ of bedded mud-rich MTDs, 554’ of mud-rich 

overbank deposits and 318’ of mud-rich discontinuous channel/levee and overbank deposits with thin 

sand seams and pockets. 

 Unit 3 Blue Unit (2,072’ – 3,108’ BML) – 1036’ of basin floor fan that is sand-rich with discontinuous 

moderate to high amplitude reflectors. 

 Unit 4 (3,108’ – 3,869’ BML) – 761’ of mud-rich turbidites and MTDs with possible thin sand seams. 

 Unit 5 (3,869’ – 6,091’ BML) – 629’ of discontinuous mud-rich MTDs with possible thin sand seams 

and layers, and 1,593’ of mud-rich turbidites. 

Shallow Water Flow Potential 

 Negligible Potential – Seafloor to 615’ BML

 Low Potential – 615’ to 1,754’ BML

 Moderate Potential – 1,754’ to 2,072’ BML

 High Potential – 2,072’ to 3,108’ BML

 Low Potential – 3,108’ to 3,869’ BML

 Moderate Potential – 3,869’ to 4,498’ BML

 Low Potential – 4,498’ to 6,091’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor to 1,754’ BML

 Low Potential – 1,754’ to 6,091’ BML

A high amplitude reflector is identified 500 feet east of this location in Unit 2 (615’ – 2,072’ BML). This 

location will not penetrate any high amplitude reflectors. 

Benthic/Anchor Assessment, MC 720, Proposed Location G (no anchors – DP Vessel) 

Mississippi Canyon 720, Proposed Location G is located in a water depth of approximately 3,125’. 

There is no evidence of seafloor or near-surface faulting, slumping, amplitudes or fluid expulsions within 

2,000’ of this location. This location will not disturb any areas of high-density benthic communities. 

There are no marine avoidance areas identified within 2,000’ of location. Sonar target 62 is located 2,085’

east of location with a 100’ avoidance area. This 100’ avoidance area does appear within the 2,000’ 

clearance area for location. 

Shell’s 18” oil flowline is identified 2,200’ east of location. Although this flowline is not within 2,000’ of 

location, the 500’ avoidance for the flowline is.

Currently, there are no existing surface locations within 2,000’ of location. 

Page 37 Public Information Copy
Conclusion: 

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 720, Proposed Location G appears suitable for the planned activity. 

Site Assessment, MC 722, Proposed Location H: 

Mississippi Canyon 722, Proposed Location H is located in a water depth of approximately 3,734’. 

The stratigraphy at the site of MC 722, Proposed Location H consists of: 

 Unit 1 (Seafloor – 570’ BML) – 19’ of drape over 451’ of alternating intervals of bedded clays and 

chaotic mass-transport deposits (MTDs), and 100’ of chaotic MTDs with possible thin sand seams and 

pockets. 

 Unit 2 (570’ – 1,443’ BML) – 962’ of alternating bedded mud-rich turbidites, muddy MTDs. 

 Unit 3 Blue Unit (1,443’ – 2,528’ BML) – 1,095’ of basin floor fan that is sand-rich with discontinuous 

moderate to high amplitude reflectors. 

 Unit 4 (2,528’ – 3,039’ BML) – 511’ of mud-rich turbidites and MTDs with possible thin sand seams. 

 Unit 5 (3,039’ – 4,271’ BML) – 1,232’ of discontinuous mud-rich turbidities and chaotic MTDs with 

possible thin sand pockets and layers. 

Shallow Water Flow Potential 

 Negligible Potential – Seafloor to 470’ BML

 Low Potential – 470’ to 570’ BML

 Negligible Potential – 570’ to 1,443’ BML

High Potential – 1,443’ to 2,528’ BML

 Low Potential – 2,528’ to 4,271’ BML

Shallow Gas Potential 

 Negligible Potential – Seafloor to 1,443’ BML

 Low Potential – 1,443’ to 4,271’ BML

There are no high-amplitude reflectors identified within 500 feet of Proposed Location H. 

Benthic/Anchor Assessment, MC 722, Proposed Location H (no anchors – DP Vessel) 

Mississippi Canyon 722, Proposed Location H is located in a water depth of approximately 3,734’. 

There is no evidence of seafloor or near-surface faulting, slumping, amplitudes or fluid expulsion features 

within 2,000’ of proposed location. This location will not disturb any high-density areas of benthic 

communities. 

There are no marine avoidances identified within 2,000’ of proposed location. 

Currently, there are no existing surface locations or flowlines within 2,000’ of proposed location. 

Conclusion: 

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 722, Proposed Location H appears suitable for the planned activity. 

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B. Topographic Features Map

The proposed activities are not within 1,000' of a no-activity zone or within the 3-mile radius zone of an 

identified topographic feature. Therefore, no map is required per NTL No. 2008-G04. 

C. Topographic Features Statement (Shunting)

Shell does not plan to drill more than two wells from the same surface location within the Protective Zone of 

an identified topographic feature. Therefore, the topographic features statement required by NTL No. 2008-

G04 is not applicable. 

D. Live Bottoms (Pinnacle Trend) Map

The activities proposed in this plan are not within 200' of any pinnacle trend feature with vertical relief equal 

to or greater than 8'. Therefore, no map is required per NTL No. 2008-G04. 

E. Live Bottoms (Low Relief) Map

The activities proposed in this plan are not within 100' of any live bottom low relief features. Therefore, no 

map is required per NTL No. 2008-G04. 

F. Potentially Sensitive Biological Features

The activities proposed in this plan are not within 200' of any potentially sensitive biological features. 

Therefore, no map is required per NTL No. 2008-G04. 

G. Remotely Operated Vehicle (ROV) Monitoring Plan

In accordance with the provisions of NTL 2008-G06, Remotely Operated Vehicle Surveys in Deepwater, 

Mississippi Canyon Blocks 720, 721 & 722 are located in Grid 13. Grid 13 is an area that does have adequate 

ROV survey coverage; therefore we are not required to run the pre- and post-ROV survey in accordance with 

NTL 2008-G06. 

H. Threatened and Endangered Species Information

Under Section 7 of the Endangered Species Act (ESA) all federal agencies must ensure that any actions they 

authorize, fund, or carry out are not likely to jeopardize the continued existence of a listed species, or destroy 

or adversely modify its designated critical habitat. 

In accordance with the 30 CFR 250, Subpart B, effective May 14, 2007 and further outlined in Notice to 

Lessees (NTL) 2008-G04, lessees/operators are required to address site-specific information on the presence 

of federally listed threatened or endangered species and critical habitat designated under the ESA and marine 

mammals protected under the Marine Mammal Protection Act (MMPA) in the area of proposes activities under 

this plan. 

Currently there are no designated critical habitats for the listed species in the Gulf of Mexico Outer 

Continental Shelf; however, it is possible that one or more of these species could be seen in the area of our 

operations. The following table reflects the Federally-listed endangered and threatened species in the lease 

area and along the northern Gulf coast: 

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Common Name Scientific Name T/E Status

Hawksbill Turtle Eretmochelys imbricata E

Green Turtle Chelonia mydas T/E

Kemp's Ridley Turtle Lepidochelys kempii E

Leatherback Turtle Dermochelys coriacea E

Loggerhead Turtle Caretta caretta T

Table 6.6 – Threatened and Endangered Sea Turtles 

The green sea turtle is threatened, except for the Florida breeding population, which is listed as endangered. 

There are 29 species of marine mammals that may be found in the Gulf of Mexico (see Table 6.7 below). 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

North Atlantic Right Whale Eubalaena glacialis E

Pantropical Spotted Dolphin Stenella attenuata

Pygmy Killer Whale Feresa attenuata

Pygmy Sperm Whale Kogia breviceps

Risso's Dolphin Grampus griseus

Rough-toothed Dolphin Steno bredanensis

Sei Whale Balaenoptera borealis E

Short-finned Pilot Whale Globicephala macrorhynchus

Sowerby's Beaked Whale Mesoplodon bidens

Sperm Whale Physeter macrocephalus E

Spinner Dolphin (Long-snouted) Stenella longirostris

Striped Dolphin Stenella coeruleoalba

Florida manatee Trichechus manatus E

Table 6.7 – Threatened and Endangered Marine Mammals 

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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. The Environmental Impact Analysis found in Section 18 

discusses potential impacts and mitigation measures related to threatened and endangered species. 

I. Archaeological Report

The following reports were used in this analysis: 

C&C Technologies, Archaeological Assessment Report, Blocks 676-678, 720-722, 765-766, and Vicinity, 

Mississippi Canyon Area, Project No. 097403-097494, December, 2009. AUV side-scan sonar and sub-bottom 

profiler data. 

C&C Technologies, Archaeological and Hazard Report, Blocks 808, 809, 852, 853 and Vicinity, Mississippi 

Canyon Area, Project No. 083986-084109, February, 2009. AUV side-scan sonar and sub-bottom profiler 

data. 

C&C Technologies, Archaeological Assessment Report, Block 854 and Vicinity (Blocks 809-811, 853, 855, 897-

899), Mississippi Canyon Area, Project No. 072879-072915, August 2007. AUV side-scan sonar and subbottom profiler data. 

Archaeological Analysis

Dec 2009 Report: 

Assessment of 2006, 2008, and 2009 survey data from Blocks 675-679, 719-723 and 763-767, Mississippi 

Canyon Area revealed 302 unidentified sonar contacts. These contacts appear to be mostly the result of 

lease development activity, or dumped barrels of industrial waste. They may represent hazards to lease 

development, but no areas are recommended for investigation or avoidance on the basis of archaeological 

potential, except the unidentified target located in Block 765, Mississippi Canyon Area that BOEM has 

established a 1,000’ avoidance zone around. 

Shipwreck remains possibly could exist undetected or unidentified within the survey area. If wood beams, 

planking, ceramics, or other possibly cultural materials are encountered during lease development, the BSEE 

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

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

(See NTL No. 2005-G07, Archaeological Resource Surveys and Reports, Sections “Authority” through 

“Required Notification of the Discovery of Shipwrecks on the Seafloor”).

Feb 2009 Report: 

Assessment of the 2006, 2007, and 2008 survey data from Blocks 764-766, 807-810, 851-854, and 895-898, 

Mississippi Canyon Area revealed 1,334 unidentified sonar contacts. None of the sonar contacts are 

suggestive of significant submerged cultural resources. These contacts appear to be mostly the result of 

lease activity, or dumped barrels of industrial waste. They may represent hazards to lease development, but 

no areas are recommended for investigation or avoidance of the basis of archaeological potential. 

Shipwreck remains possibly could exist undetected or unidentified within the survey area. If wood beams, 

planking, ceramics, or other possibly cultural materials are encountered during lease development, the BSEE 

archaeologists should 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 BOEM personnel 

(See NTL No. 2005-G07, Archaeological Resource Surveys and Reports, Sections “Authority” through 

“Required Notification of the Discovery of Shipwrecks on the Seafloor”).

Page 41 Public Information Copy
Aug 2007 Report: 

The assessment of the survey data in Block 854, and vicinity, Mississippi Canyon Area revealed at least two 

hundred eighty-eight (288) unidentified sonar contacts within the survey area. These contacts are likely 

modern debris resulting from lease activity, other shipping activity, or dumped barrels of industrial waste. If 

the contacts are barrels of industrial waste, they may represent a potential biological hazard. None of these 

contacts are suggestive of significant submerged cultural resources and none are recommended for 

avoidance because of archaeological concerns. 

A possibility exists that shipwreck remains could be undetected or unidentified within the survey area. If 

wood beams, planking, ceramics or other possibly cultural materials are encountered during lease 

development, the BSEE 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 BOEM personnel. 

Shell will comply with all conditions of NTL 2008-G20. 

J. Air and Water Quality Information

Mississippi Canyon Block 720 is located 39 miles from the nearest shoreline. Drilling/completion operations 

will produce air pollutant emissions, but as provided in the Air Emissions Spreadsheet (see Section 8 of this 

Plan), these operations are below the exemption levels. 

These drilling operations will result in the discharge of authorized effluents under the EPA Region VI General 

permit. Impacts of these discharges are expected to be minimal on water quality in the area. 

For specific information relating to air and water quality information please refer to Section 18. 

K. Socioeconomic Information

1) Shell will utilize its existing shorebase located in Fourchon, Louisiana which is fully staffed and 

operational and does not expect to employ persons from within the State of Florida. 

2) Shell does not expect to purchase major supplies, services, energy, water or other resources from 

within the State of Florida for these operations. 

3) Shell does not expect to hire contractors or vendors from within the State of Florida. 

For specific information relating to socioeconomic information please refer to Section 18 in this Plan. 

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OLYMPUS Host – MARS “B” Development 

MISSISSIPPI CANYON BLOCK 807 

Waste Barrel Avoidance and Release 

Response in the Mississippi Canyon 

Area 

Project OLYMPUS Host – MARS “B” Development 

Document Title Waste Barrel Avoidance and Release 

Response in the Mississippi Canyon Area 

Document Number MRB-100-HX-0505-0000002-000

Document Revision REV 2 

Version Code Not Applicable 

Document Status Issued for Review 

EIS Discipline / Document Type Hazard Analysis Report

Originator / Author Robert Kuehn 

Classification Restricted 

ECCN EAR 99 

Issue Date 10/20/10 

Revision History is shown on next page 

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Document Number -Rev Page 2 of 8 

RESTRICTED

REVISION HISTORY 

Rev # Date of 

Issue 

Issue Description Originator Reviewer Approver 

2 10/20/10 Formalized existing 

document into 

Document Mgmt 

program 

RB Kuehn RB Kuehn Nilesh Popat 

 

 

 

 

 

 

 

 

Summary 

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Document Number -Rev Page 3 of 8 

RESTRICTED

Contents 

PURPOSE ............................................................................................................................ 4

REVISION HISTORY ....................................................................................................... 4

BACKGROUND ................................................................................................................. 4

NORMAL OPERATIONS ....................................................................................................... 5

DECONTAMINATION OF EQUIPMENT ................................................................................... 6

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Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

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Purpose 

This document provides expectations and guidance for avoiding, and responding to a release of 

the contents of, a seafloor waste barrel. The procedures below describes Shell’s expectations for 

routine barrel avoidance, data management, and response to inadvertent release of barrel 

contents. 

Applicability 

This document applies to all ROV, anchor and other operations which could cause a seafloor 

barrel rupture. 

Changes to this procedure must be approved by BOEMRE.1 

Revision History 

Date Person Revision 

12/16/08 RBKuehn Incorporated comments from MMS2 and issued as final. 

8/16/10 RBKuehn Incorporated comment from BOEMRE3 to include New Orleans District 

manager in the notification of Step 2 of the section Barrel Impact Reporting. 

Also revised all relevant references to MMS as BOEMRE 

10/20/10 RBKuehn 3⁄4 In Background, added in summary of suspected materials disposed at the 

site, based on research of the site in public records. 

3⁄4 In section on Equipment Decontamination- Decon Procedure:

o clarified what types of detergents are preferred/allowed, using the 

NPDES Vessel General Permit as a guide. 

o Expanded on appropriate PPE and other personnel precautions 

o Noted a need for secondary containment as appropriate 

Significant changes to the text are shown in yellow shade. 

3⁄4 Added page numbers and cleaned up format. 

 

3⁄4 Issued as REV 2 

Background 

Various projects will be carried out in an area of the Mississippi Canyon known to contain 

barrels of chemical waste. 

 

1 Per MMS approval of West Boreas Supplemental Exploration Plan, MS 5231 December 16, 2008 

Control No. S-07273, Lease(s) OCS-G07957, Block 762, Mississippi Canyon Area OCS-G07962, Block 806, 

Mississippi Canyon Area

2 Per MMS approval of West Boreas Supplemental Exploration Plan, MS 5231 December 16, 2008 

Control No. S-07273, Lease(s) OCS-G07957, Block 762, Mississippi Canyon Area OCS-G07962, Block 806, 

Mississippi Canyon Area

3

 Per BOEM approval of the Supplement to the Conceptual DWOP for Mars B project, 8/12/10, MS 5220 

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Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

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• The barrels were discharged in this area in the 1970’s under government approved 

permits. 

• The content, and its toxicity, of each individual barrel is not known. However, there are 

records of a wide range of industrial waste materials that were disposed in the barrels 

including chlorinated hydrocarbons and liquid metal salts. Below is a summary of the 

barrel contents based on available records. 

1. Metallic sodium and calcium; calcium oxide, sodium oxide, and inert salts.4 

2. 80-90% dichlorobutene, 20% organic high-boilers, and 1% quaternary 

ammonium salts. “Other wastes produced from the manufacture of fungicides 

and herbicides”.5

• Within the area there are/could be many hundreds of waste barrels. Many of the barrels 

may have released their contents over time. However, an unknown number of barrels still 

look intact, and they may or may not still contain their original content. Also, as some of 

the barrels contained metal based solid waste, some of the barrels that no longer look 

intact may still contain some waste. 

• Extensive sonar surveys of the area exist and are available for planning purposes. 

Potential Hazards 

Although there are no records of any issues regarding the barrels during the many years of Oil 

and Gas operations in the Mississippi Canyon area, the following potential hazards exist: 

• Personnel exposure or equipment damage due to adherence of waste chemicals to 

recovered subsea equipment 

• Equipment damage from sodium exposure to water (very vigorous reaction). 

Normal Operations 

For normal operations, all contractors and Shell employees must meet the following 

expectations: 

1. Shell’s over-arching policy is to avoid barrel contact. 

2. Press releases making any reference to the chemical waste or barrels, or any incidents 

involving any chemical waste or barrels, will require the express written permission from 

 

4

 EPA Permit Application No. 730D009E from Ethyl Corp, March 1, 1977, Public Notice April 20, 1977, 5

 Chapter 5 “Ocean Discharge” in the book Assessing Potential Ocean Pollutants, A Report of the Study Panel on Assessing 

Potential Ocean Pollutants. National Academy of Sciences, Washington DC, 438 pp. This document details DuPont’s application 

to dispose of the following at the ocean disposal site

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Shell. 

3. All recorded video material is confidential and the property of Shell (standard contract 

provision). 

If during normal ROV operations there is a discovery of any potential archaeological 

resource (i.e., cannot be definitively identified as waste barrel/barrel remnant, modern debris, 

or refuse), any seafloor-disturbing activities in its proximity, must be stopped, the discovery 

must be reported to Dr. Chris Horrell at 504-736-2796, and further instructions must be 

obtained before proceeding. 

4. Equipment Placement/Stand-off Distance

4.1. A safe stand-off distance from the waste barrels is considered 10m (33ft). Care must be 

taken that flexible components (e.g. ROV tether, anchor lines, seismic cables) are 

controlled as well (e.g. don’t drag through a barrel field). 

4.2. If a seafloor action will generate cuttings or debris, increase the stand-off distance as 

needed to avoid debris contact with nearby barrels. 

4.3. Do not investigate any barrels or remainders of barrels. Remain the minimum stand-off 

of 10m (33ft) at all times. 

4.4. Survey the anchor/pile/export locations with an ROV to ensure barrel avoidance. 

4.5. Record the (approximate) location of any chemical waste barrel seen, if feasible, 

without getting closer than the 10m (33ft) stand-off distance. 

5. Contact the Shell EP Company Environmental Duty Phone for any questions or concerns. 1-

504-390-1330 

6. Decontamination of Equipment: In the event of contact with a barrel contents decontaminate 

equipment per Decontamination of Equipment below. 

7. Make reports of barrel contact/rupture per Barrel Release Reporting below. 

Decontamination of Equipment 

1. General 

In the unlikely case that contact is suspected or has been made with any wastes from a barrel, 

appropriate action needs to be taken to guarantee the topside safety of personnel handling the 

equipment (e.g. ROV, anchor lines, etc). 

It is left solely to the judgment of the Person-in-Charge of the 

equipment/vessel to determine if it is necessary to abandon all or part of 

the equipment on the sea floor. 

2. Decon Procedure 

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Based on various factors6

, Shell recommends the following: 

2.1. Use the ocean to “wash” the equipment (e.g. fly an ROV for at least an hour at depth 

high enough above sea floor to prevent umbilical dragging or other disturbance of the 

sea floor). For other equipment, provide any movement through the water column 

that’s possible, again avoiding seafloor dragging. 

2.2. Retrieve the equipment to the surface, but do not bring onboard if feasible. 

2.3. Hose the equipment off before retrieving onto the vessel. Use as high a water flow as 

is available/safe. CAUTION- detergent/soap may be used BUT in as low a quantity 

as practicable to minimize foam. Only non-toxic and phosphate free cleaners and 

detergents may be used. Furthermore, cleaners and detergents should not be caustic or 

only minimally caustic and should be biodegradable7. 

2.4. Avoid physical contact with the equipment, and keep the equipment off the vessel at 

this point.. 

2.5. Dunk the equipment back in the sea and “wash” the equipment for approximately 15 

minutes. 

2.6. Retrieve the equipment to the surface. Before recovering, visually inspect the 

equipment, umbilical, cable surfaces with binoculars for signs of corrosion, 

discoloration, air reaction such as fuming/smoking, or any other signs of chemical 

contact. Rewash and dunk the equipment as needed. 

2.7. Retrieve the equipment onto the back deck. Monitor the equipment and surrounding 

storage area for indications of chemical contamination (corrosion, discoloration, air 

reaction such as fuming/smoking, etc). Establish secondary containment as necessary 

to collect any potentially contaminated drips. 

2.8. Only essential personnel should be allowed near the equipment, once retrieved on the 

back deck. 

2.9. While performing cleaning operations on the equipment, involving contact with 

potentially contaminated surfaces, personal protective equipment must be worn 

including, but not limited to: safety eye goggles, safety clothing such as coverall and 

 6 Shell assumes, for purposes of this decontamination guidance, that: 

• The most toxic material identified in the disposal area’s permits and other available documents is involved . However Shell cannot guarantee 

there are not other toxic materials present than those identified in the permits and other documents. 

• It is assumed that the materials do not chemically interact with the materials of the ROV, its tools and equipment. 

7

 The NPDES General Permit for Discharges Incidental to the Normal Operation of a Vessel provides insight into managing any 

washing. Also, EPA provides the following definitions: 

“Non-toxic” soaps, cleaners, and detergents means these materials which do not exhibit potentially harmful characteristics as 

defined by the Consumer Product Safety Commission regulations found at 16 CFR Chapter II, Subchapter C, Part 1500. 

“Phosphate Free” soaps, cleaners, and detergents means these materials which contain, by 

weight, 0.5% or less of phosphates or derivatives of phosphates.

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Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

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aprons, Nitrile type chemical resistant industrial-safety gloves, and PVC boots. 

2.10. Wash hands thoroughly and take a shower after performing cleaning operations on 

the equipment. 

2.11. Avoid drinking liquids or eating food in the work area. 

2.12. If contamination is still suspected, consult with the Shell representatives/management 

for further actions including additional washing, abandonment on the seafloor, 

segregated storage on the boat, wrapping the equipment partially or fully in plastic 

sheeting, etc. 

2.13. Document all actions and results in a log. 

Barrel Impact Reporting 

1. Initial reporting:

1.1. Equipment operator is to inform the Shell onsite representative and the Shell 

operations supervisor on duty. 

1.2. The Shell onsite representative or the Shell operations supervisor will call the 

SEPCO Environmental Duty Engineer at 1-504-390-1330. As a back-up, call 337-

281-0783 (Rob Kuehn). 

• The call should be made at the earliest convenience. 

• Be prepared to report the lat/long of the ruptured barrel (not the surface location) 

and water depth. 

2. The SEPCO Environmental Duty Engineer will call 

• the regulatory Affairs Duty Phone 504-782-7823, 

• Mr. Broussard of the BOEMRE (504-736-3245) and 

• BOEMRE New Orleans District Manager 

to report the event. The call should include the lat/long and any circumstances of note. 

3. Follow-up Reporting

The SEPCO Environmental Duty Engineer or Rob Kuehn follows up with an email to 

Mr. Broussard of BOEMRE. 

The BOEMRE have requested submission of a copy of whatever relevant video is 

available for the event period. No dedicated video survey is required for a barrel rupture 

(i.e. just be prepared to submit whatever video was obtained as normal part of the 

activities). BOEM has agreed we can submit any video after the project is completed. 

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Attachment 6A – Enhanced Seafloor Rendering Map 

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Attachment 6B – Enhanced Seafloor Rendering Map 

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Attachment 6C – Enhanced Seafloor Rendering Map 

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Attachment 6D – Enhanced Seafloor Rendering Map 

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Attachment 6E – Enhanced Seafloor Rendering Map 

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Attachment 6F – Enhanced Seafloor Rendering Map 

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Attachment 6G – Enhanced Seafloor Rendering Map 

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Attachment 6H – Enhanced Seafloor Rendering Map 

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SECTION 7: WASTE AND DISCHARGE INFORMATION

A. Projected Ocean Discharges 

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

Type of Waste and Composition Composition 

Projected Amount

per well Discharge rate/day Discharge Method Answer yes or no

Will drilling occur ? If yes, you should list muds and cuttings

EXAMPLE: Cuttings wetted with ynthetic based fluid 

Cuttings generated while using synthetic 

based drilling fluid. X bbl/well X bbl/day discharge pipe No

Water-based drilling fluid barite, additives, mud 120,000 bbl/well 20,000 bbls /day discharge overboard No

Cuttings wetted with water-based fluid

Cuttings coated with water based drilling 

mud 2,871 bbls / well 478 bbls /day discharge overboard No

Cuttings wetted with synthetic-based fluid 

Cuttings generated while using synthetic 

based drilling fluid. 5,510 bbls/well 55 bbls /day discharge overboard No

Chemical product waste 50 bbls/well 2 bbl/day

Treated to meet NPDES limits and 

discharged overboard No

Will humans be there? If yes, expect conventional waste

EXAMPLE: Sanitary waste water X liter/person/day NA chlorinate and discharge No

Domestic waste (kitchen water, shower water) grey water 19,200 bbls/day/well 160 bbls/day

Grinded to less than 25 mm mesh size 

and discharge overboard No

Sanitary waste (toilet water) treated sanitary waste 12,000 bbl/day/well 100 bbls/day

Treated in the MSD** prior to discharge 

to meet NPDES limits No

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

Deck Drainage Contaminated wash and rainwater 2,400 bbls / well 20 bbls / day

Drained overboard through deck 

scuppers No

Will you conduct well treatment, completion, or workover? 

well treatment fluids NA NA NA NA No

well completion fluids NA NA NA NA No

workover fluids NA NA NA NA No

Miscellaneous discharges. If yes, only fill in those associated with your activity. 

Desalinization unit discharge Rejected water from watermaker unit 49,400 bbls / well 412 bbls/day discharge overboard No

Blowout prevent fluid Water based 400 bbls/well 0.2 bbls /day Subsea BOP @ seafloor No

Ballast water Uncontaminated seawater 260,000 bbls / well 2,200 bbls / day discharge overboard No

Bilge water

Bilge and drainage water will be treated to 

MARPOL standards (< 15ppm oil in water). 260,000 bbls / well 2,200 bbls / day

Bilge and drainage water will be treated 

to MARPOL standards (< 15ppm oil in 

water). No

Excess cement at seafloor Cement slurry 28,200 bbls/well 235 bbls /day 

discharged through shunt line, 77' below 

waterline No

Fire water Treated seawater 8,000 bbls / well 2,000 bbls / month

Drained overboard through deck 

scuppers No

Cooling water Treated seawater 54,760,000 bbls / well 456,343 bbl/day/well

discharged through shunt line, 77' below 

waterline No

Will you produce hydrocarbons? If yes fill in for produced water.

Produced water 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 DISCHARGE TO THE GOM

Projected 

Downhole 

Projected generated waste Projected ocean discharges Disposal

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B. Projected Generated Wastes 

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, Fourchon, 

LA 52,000 bbls Recycled

Cuttings wetted with Water-based fluid NA NA NA NA NA

Cuttings wetted with Synthetic-based fluid NA NA NA NA NA

Cuttings wetted with oil-based fluids NA NA NA NA NA

Will you produce hydrocarbons? If yes fill in for produced sand.

Produced sand NA NA NA NA NA

EXAMPLE: trash and debris cardboard, aluminum, barged in a storage bin shorebase z tons total recycle

Trash and debris - recyclables trash and debris storage bins on supply boat

Omega Waste Managmenet, W. 

Patterson, LA or ARC, New Iberia, LA 200 lbs/month recylce

Trash and debris - non-recyclables trash and debris storage bins on supply boat

Republic/BFI landfill, Sorrento, LA or 

the parish landfill, Avondale, LA 400 lbs/month landfill

Used oil and glycol

used oil, oily rags and pads, 

empty drums and cooking 

oil drums on supply boat

Omega Waste Managmenet, W. 

Patterson, LA or ARC, New Iberia, LA 20 bbls/month recycled

Hazardous Waste

paints, solvents and unused 

chemicals drums on supply boat Safety Kleep, Denton, TX 60 bbls/mo recycled

Universal Waste Items

Batteries, lamps, glass and 

mercury-contaminated 

waste drums on supply boat Lamp Environmental, Hammond, LA 50 bbls/mo landfill

NOTE: If you will not have a type of waste, enter NA in the row. 

Waste Disposal

TABLE 7B. WASTES YOU WILL TRANSPORT AND/OR DISPOSE OF ONSHORE 

Will you have additional wastes that are not permitted for discharge? If 

yes, fill in the appropriate rows. 

Note: Please specify whether the amount reported is a total or per well

Projected generated waste

C. Modeling Report

The proposed activities under this plan do not meet the U.S. Environmental Protection Agency requirements for an individual NPDES permit. Therefore, modeling 

report requirements per NTL No. 2008-G04 is not applicable to this EP. 

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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

 *Section 4 of this plan discusses H2S as “unknown” although H2S may be encountered. 

 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

B. Worksheets 

See Attachment 8A. 

Page 61 Public Information Copy
Attachment 8A – Air Quality Report 

COMPANY Shell Offshore Inc.

AREA MC

BLOCK 720, 721, 722

LEASE 33170, 33171, 33172

PLATFORM MODU

WELL A - H

COMPANY 

CONTACT Jeff McMenis

TELEPHONE NO. 504-728-6021

REMARKS SEPCO Env File Name - Queen_AQR_EP_NJD_091912.xlsx

Page 62 Public Information Copy
Fuel Usage Conversion 

Factors

Natural Gas 

Turbines

Natural 

Gas 

Engines

Diesel 

Recip. 

Engine

REF. DATE

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

Equipment/Emission Factors units PM 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

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

maximum sulfur, effective June 1, 2007.

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

Page 63 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc. MC 720, 721, 722 33170, 33171, 33172 MODU A - H Jeff McMenis 504-728-6021 SEPCO Env File Name - Queen_AQR_EP_NJD_091912.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

DRILLING PRIME MOVER>600hp diesel 6786 327.7638 50% 3933.17 24 165 4.78 2.74 164.42 4.93 35.87 4.74 2.72 162.77 4.88 35.51

PRIME MOVER>600hp diesel 6786 327.7638 50% 3933.17 24 165 4.78 2.74 164.42 4.93 35.87 4.74 2.72 162.77 4.88 35.51

PRIME MOVER>600hp diesel 6786 327.7638 50% 3933.17 24 165 4.78 2.74 164.42 4.93 35.87 4.74 2.72 162.77 4.88 35.51

PRIME MOVER>600hp diesel 6786 327.7638 50% 3933.17 24 165 4.78 2.74 164.42 4.93 35.87 4.74 2.72 162.77 4.88 35.51

PRIME MOVER>600hp diesel 6786 327.7638 50% 3933.17 24 165 4.78 2.74 164.42 4.93 35.87 4.74 2.72 162.77 4.88 35.51

PRIME MOVER>600hp diesel 6786 327.7638 50% 3933.17 24 165 4.78 2.74 164.42 4.93 35.87 4.74 2.72 162.77 4.88 35.51

PRIME MOVER>600hp diesel 6786 327.7638 50% 3933.17 24 165 4.78 2.74 164.42 4.93 35.87 4.74 2.72 162.77 4.88 35.51

PRIME MOVER>600hp diesel 6786 327.7638 50% 3933.17 24 165 4.78 2.74 164.42 4.93 35.87 4.74 2.72 162.77 4.88 35.51

Energency Generator>600hp diesel 2550 123.165 100% 2955.96 1 165 1.80 1.03 61.78 1.85 13.48 0.15 0.09 5.10 0.15 1.11

AUXILIARY EQUIP<600hp (wireline unit)300 14.49 100% 347.76 24 15 0.66 0.12 9.25 0.74 2.00 0.12 0.02 1.67 0.13 0.36

Supply Vessel>600hp diesel (general support) 9440 455.952 50% 5471.42 24 155 6.65 3.82 228.72 6.86 49.90 6.19 3.55 212.71 6.38 46.41

Crew Vessel>600hp diesel 5400 260.82 50% 3129.84 24 50 3.81 2.18 130.84 3.93 28.55 1.14 0.65 39.25 1.18 8.56

Supply Vessel>600hp diesel (spud activity) 9440 455.952 50% 5471.42 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 (spud activity) 9440 455.952 50% 5471.42 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 (spud activity) 9440 455.952 50% 5471.42 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

FACILITY

INSTALLATION

MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 0.00

DRILLING OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

WELL TEST GAS FLARE 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

2013-2020 YEAR TOTAL 71.14 40.54 2432.11 73.43 530.63 46.68 26.72 1602.09 48.15 349.54

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 1631.70 1631.70 1631.70 1631.70 45527.76

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

Average 

Engine 

Loads %

Page 64 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore 

Inc. MC 720, 721, 722 33170, 33171, 33172 MODU A - H

Emitted Substance

Year

PM SOx NOx VOC CO

2013-2020 46.68 26.72 1602.09 48.15 349.54

Allowable 1631.70 1631.70 1631.70 1631.70 45527.76

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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 250. An update to the Regional OSRP was filed with the 

BSEE October 26, 2010, March 15, 2011, May 31, 2011, July 6, 2011 and August 1, 2011, January, 

February and March 2012 and July 2012, and is pending approval. An updated OSRP Certification in 

accordance with 30 CFR 254.2 was accepted by the BSEE in July 2012. 

Spill Response sites are as follows: 

Primary Response Equipment Locations Preplanned Staging Location(s) 

Venice, LA; Ft Jackcon, 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 Sub-Regional OSRP EP

Type of Activity1Subsea Drilling Exploratory Drilling 

Facility Location (area/block) MC 391 MC 721

Facility Designation2Subsea well 1◊ Subsea well D

Distance to Nearest Shoreline (miles) 70 49

Volume3

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

392,000** BOPD

355,000 Bbls

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

diesel)

Crude oil Crude oil

API Gravity(s)426o 28o

Table 9.2 - Worst Case Scenario Determination 

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

**24 hour rate (330,000 BOPD 30 day average) 

◊This well was reviewed and accepted by BOEM on July 10, 2012 during the drilling of the well. The 30-day 

average was updated in update to the OSRP July 2012

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

its regional OSRP, filed with the BSEE October 26, 2010 and updated March 15, 2011, May 31, 2011, July 6, 

2011 and August 1, 2011, January, February, March and July 2012 and is pending approval, 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 66 Public Information Copy
B. Oil Spill Response Discussion

1. Volume of the Worst Case Discharge 

Please refer to Section 2J and 9D of this EP. 

2. Trajectory Analysis 

Trajectories of a spill and the probability of it impacting a land segment have been projected 

utilizing information in the BOEMRE Oil Spill Risk Analysis Model (OSRAM) for the Central and 

Western Gulf of Mexico available on the BOEMRE website using 30 day impact. Offshore areas along 

the trajectory between the source and land segment contact could be impacted. The land segment 

contact probabilities are shown in Table 9.C.1. 

Area/Block OCS-G

Launch

Area Land Segment Contact %

Exploratory

MC721 33171 57

Galveston, TX 1 

Jefferson, TX 1 

Cameron, LA 3 

Vermillion, 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 BOEM 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 721 WCD scenario. 

Onshore/Nearshore: Plaquemines Parish has been identified as the most probable impacted 

Parish within the Gulf of Mexico for the Greater than 10 Mile Worst Case Discharge and the 

Exploratory Worst Case Discharge. Plaquemines Parish has a total area of 2,429 square miles of 

which, 845 square miles of it is land and 1,584 square miles is water. Plaquemines Parish includes 

two National Wildlife Refuges: Breton National Wildlife Refuge and Delta National Wildlife Refuge. 

This area is also a nesting ground for the brown pelican, an endangered species. Examples of 

Environmental Sensitivity maps for Plaquemines Parish are detailed in the following pages. Key ESI 

maps for Plaquemines Parish and the legend are shown in Figures 9.C.1through 9.C.5. 

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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 721 Worst Case Discharge as effectively as 

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

Mississippi Canyon Block 721

Calculations

(BBLS)

i. TOTAL WCD (based on 30 day average (per day)) ~352,000

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

per day)*

(6% Natural surface evaporation and dispersion in 24 hrs)

-21,100

TOTAL REMAINING ~330,900

Table 9.D.1 Oil Remaining After Surface Dispersion

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

account for surface dispersion and evaporation. 

Shell has contracted OSROs to provide equipment, personnel, materials and support vessels as well 

as temporary storage equipment to be considered in order to cope with a WCD spill. Under adverse 

weather conditions, major response vessels and Transrec skimmers are still effective and safe in sea 

states of 6-8 ft. If sea conditions prohibit safe mechanical recovery efforts, then natural dispersion 

and airborne chemical dispersant application (visibility & wind conditions permitting) may be the 

only safe and viable recovery option. 

MSRC OSRV 8 foot seas

VOSS System 4 foot seas

Expandi Boom 6 foot seas, 20 knot winds

Dispersants Winds more than 25 knots,

Visibility less than 3 nautical miles, or

Ceiling less than 1,000 feet.

Table 9.D.2 Operational Limitations of Response Equipment 

Upon notification of the spill, Shell would request a partial or full mobilization of contracted 

resources, including, but not limited to, skimming vessels, oil storage vessels, dispersant aircraft, 

subsea dispersant, shoreline protection, wildlife protection, and containment equipment. Following 

is a list of the contracted resources including de-rated recovery capacity, personnel, and estimated 

response times (procurement, load out, travel time to the site, and deployment). The Incident 

Page 68 Public Information Copy
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 23 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 721 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 853,000 

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

equipment equals approximately 1,038,000 barrels. 

De-rated Recovery Rate

(bopd)

Storage

(bbls)

Offshore Recovery and 

Storage 714,920 1,031,526

Nearshore Recovery and 

Storage 138,180 7,470

Total 853,421 1,038,996

Table 9.D.3 Mechanical Recovery Combined De-Rated Capability 

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

 Table 9.D.5 Nearshore On-Water Recovery and Storage 5ctivation List 

Oil Storage: The strategy for transferring, storing and disposing of oil collected in these recovery 

zones is to utilize two 150,000-160,000 ton (dead weight) tankers mobilized by Shell (or any other 

tanker immediately available). The recovered oil would be transferred to Motiva’s Norco, LA storage 

and refining facility, or would be stored at Delta Commodities, Inc. Harvey, LA facility.

Aerial Surveillance: Aircraft can be mobilized to detect, monitor, and target response to oil spills. 

Aircraft and spotters can be mobilized within hours of an event. 

Table 9.D.6 Aerial Surveillance Activation List

Aerial Dispersant: Depending on proximity to shore and water depth, dispersants may be a viable 

response option. If appropriate and approved, 4 to 5 sorties from three DC-3’s can be made within 

the first 12 hour operating day of the response. These aerial systems could disperse approximately 

7,704 to 9,630 barrels of oil per day. Additionally, 3 to 4 sorties from the BE90 King Air and 3 to 4 

sorties from the Hercules C-130A within the first 12 hour operating day of the response could 

disperse 4,600 to 6,100 barrels of oil per day. For continuing dispersant operations, the CCA’s Aerial 

Dispersant Delivery System (ADDS) would be mobilized. The ADDS has a dispersant spray capability 

of 5,000 gallons per sortie. 

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 Table 9.D.7 Offshore Aerial Dispersant Activation List 

Vessel Dispersant: Vessel dispersant application is another available response option. If 

appropriate, vessel spray systems can be installed on offshore vessels of opportunity using inductor 

nozzles (installed on fire-water monitors), skid mounted systems, or purpose-built boom arm spray 

systems. Vessels can apply dispersant within the first 12-24 hours of the response and continually as 

directed. 

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

Subsea Dispersant: Shell has contracted with Wild Well Control for a subsea dispersant package. 

Subsea dispersant application has been found to be highly effective at reducing the amount of oil 

reaching the surface. Additional data collection, laboratory tests and field tests will help in facilitating 

the optimal application rate and effectiveness numbers. For planning purposes, the system has the 

potential to disperse approximately 24,500 to 34,000 barrels of oil per day.

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

In-Situ Burning: Open-water in-situ burning (ISB) also may be used as a response strategy, 

depending on the circumstances of the release. ISB services may be provided by the primary OSRO 

contractors. If appropriate conditions exist and approvals are granted, one or multiple ISB task 

forces could be deployed offshore. Task forces typically consist of two to four fire teams, each with 

two vessels capable of towing fire boom, guide boom or tow line with either a handheld or aeriallydeployed oil ignition system. At least one support/safety boat would be present during active 

burning operations to provide logistics, safety and monitoring support. Depending upon a number of 

factors, up to 4 burns per 12-hour day could be completed per ISB fire team. Most fire boom 

systems can be used for approximately 8-12 burns before being replaced. Fire intensity and weather 

will be the main determining factors for actual burns per system. Although the actual amount of oil 

that will be removed per burn is dependent on many factors, recent data suggests that a typical 

burn might eliminate approximately 750 barrels. For planning purposes and based on the above 

assumptions, a single task force of four fire teams with the appropriate weather and safety 

conditions could complete four burns per day and remove up to ~12,000 bbls/day. In-situ burning 

nearshore and along shorelines may be a possible option based on several conditions and with 

appropriate approvals, as outlined in Section 19, In-situ Burn Plan (OSRP). In-situ burning along 

certain types of shorelines may be used to minimize physical damage where access is limited or if it 

is determined that mechanical/manual removal may cause a substantial negative impact on the 

environment. All safety considerations will be evaluated. In addition, Shell will assess the situation 

and can make notification within 48 hours of the initial spill to begin ramping up fire boom 

production through contracted OSRO(s). There are potential limitations that need to be assessed 

prior to ISB operations. Some limitations include atmospheric and sea conditions; oil weathering; air 

quality impacts; safety of response workers; and risk of secondary fires. 

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

Shoreline Protection: If the spill went unabated, shoreline impact in Plaquemines Parish, LA would 

depend upon existing environmental conditions. Nearshore response may include the deployment of 

shoreline boom on beach areas, or protection and sorbent boom on vegetated areas. Strategies 

would be based upon surveillance and real time trajectories provided by The Response Group that 

depict areas of potential impact given actual sea and weather conditions. Strategies from the New 

Orleans, Louisiana Area Contingency Plan, Unified Command would be consulted to ensure that 

environmental and special economic resources would be correctly identified and prioritized to ensure 

optimal protection. Shell has access to shoreline response guides that depict the protection response 

modes applicable for oil spill clean-up operations. Each response mode is schematically represented 

to show optimum deployment and operation of the equipment in areas of environmental concern. 

Supervisory personnel have the option to modify the deployment and operation of equipment 

allowing a more effective response to site-specific circumstances. 

Page 70 Public Information Copy
 Table 9.D.11 Shoreline Protection and Wildlife Support List 

Wildlife Protection: If wildlife is threatened due to a spill, the contracted OSRO’s have resources 

available to Shell, which can be utilized to protect and/or rehabilitate wildlife. The resources under 

contract for the protection and rehabilitation of affected wildlife are in Table 9.D.11. 

New or unusual technology in regards to spill, prevention, control and clean-up: 

Shell will use our normal well design and construction processes with multiple barrier approach as 

well as new stipulations mandated by NTL 2008-N05. Response techniques will utilize new learnings 

from Macondo response to include in-situ burning and subsea dispersant application. Mechanical 

recovery advancements are continuing to be made to incorporate utilization of Koseq arms outfitted 

on barges, conversion of Platform Support Vessels for Oil Spill Response, and inclusion of nighttime 

spill detection radar to improve tracking capabilities (X-Band radar, Infrared sensing, etc.). In 

addition, new response technologies/techniques are continuing to be considered by Shell and the 

appropriate government organizations for incorporation into our planned response. Any additional 

response technologies/techniques presented at the time of response will be used at the discretion of 

the Unified Command and USCG. 

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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 Storage Activation List 

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

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

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

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

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

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

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Table 9.D.6 Nearshore On-Water Recovery Activation List 

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Table 9.D.6 Nearshore On-Water Recovery Activation List (continued) 

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Table 9.D.7 Aerial Surveillance Activation List 

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Table 9.D.8 Offshore Aerial Dispersant Activation List 

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Table 9.D.8 Offshore Aerial Dispersant Activation List (cont.) 

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

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Table 9.D.10 Subsea Dispersant Package Activation List 

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Table 9.D.11 In-Situ Burn Equipment Activation List 

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Table 9.D.11 In-Situ Burn Equipment Activation List (continued) 

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Table 9.D.11 In-Situ Burn Equipment Activation List (continued) 

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Table 9.D.11 In-Situ Burn Equipment Activation List (continued) 

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Table 9.D.11 In-Situ Burn Equipment Activation List (continued) 

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Table 9.D.12 Shoreline Protection and Wildlife Support List 

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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 EP 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

Mississippi Canyon Block 720, 721 & 722:

Lease OCS-G 33170, 33171 and 33172 were acquired in Lease Sale #208 held on March 18, 2009 and has an 

expected expiration date of May 31, 2019. 

These leases are not part of a biological sensitive area, known chemosynthetic area, or shipping fairway. See 

Section 6 of this plan for site specific archeological information. The following stipulations are associated with this 

lease: 

Stipulation No. 8 – Protected Species 

This Stipulation is addressed in the following sections of this plan: 

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

Section 10, Environmental Monitoring Information, Incidental takes 

Section 12, Environmental Mitigation Measures Information, Incidental takes 

Section 18, Environmental Impact Assessment 

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SECTION 12: ENVIRONMENTAL MITIGATION MEASURE INFORMATION

A. Impacts to Marine and coastal environments 

The proposed action will implement mitigation measures required by laws and regulations, including all 

applicable Federal & State requirements concerning air emissions, discharges to water and solid waste disposal, 

as well as any additional permit requirements and Shell policies. Project activities will be conducted in 

accordance with the Regional OSRP. Section 18 of this plan discusses impacts and mitigation measures, 

including Coastal Habitats and Protected Areas. 

B. Incidental Takes 

We do not anticipate any incidental takes related to the proposed operations. Shell implements the mitigation 

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

and operators from the 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”

Page 98 Public Information Copy
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. 

 

Page 99 Public Information Copy
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 6 miles from Port Fourchon to 

the mouth of Bayou Lafourche, 

then to MC 721

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. 

Page 100 Public Information Copy
Attachment 14A – Vicinity Map 

Page 101 Public Information Copy
SECTION 15: ONSHORE SUPPORT FACILITIES INFORMATION

A. General 

Name Location Existing/New/Modified

Fourchon Port Fourchon, LA Existing

Boothville Heliport Boothville, LA Existing

The onshore support bases for water and air transportation will be the existing terminals in Boothville and 

Fourchon, Louisiana. The Fourchon boat facility is operated by Shell and is located on Bayou Lafourche, south 

of Leeville, LA approximately 3 miles from the Gulf of Mexico. The existing onshore air support base in 

Boothville, LA is located at 38963 Hwy. 23, Boothville, LA 70041. 

B. Support Base Construction or Expansion 

This 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 

Since no onshore support base construction or expansion is planned for these activities, a timetable for land 

acquisition and construction or expansion is not applicable. 

D. Waste Disposal 

See Section 7, Tables 7A and 7B. 

E. Air emissions 

Not required by BOEM GOM. 

F. Unusual solid and liquid wastes 

Not required by BOEM GOM. 

SECTION 16: SULPHUR OPERATIONS INFORMATION

Information regarding Sulphur Operations is not included in this EP as we are not proposing to conduct sulphur 

operations. 

Page 102 Public Information Copy
SECTION 17: COASTAL ZONE MANAGEMENT ACT (CZMA) INFORMATION

LOUISIANA

COASTAL ZONE MANAGEMENT 

CONSISTENCY CERTIFICATION 

EXPLORATION PLAN 

Type of Plan 

 

MISSISSIPPI CANYON BLOCKS 720, 721 & 722

 Area and Blocks 

OCS-G 33170, 33171 & 33172

Lease Number 

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 Bellone 

Certifying Official 

 11/01/2012 

Date 

Page 103 Public Information Copy
SECTION 18: ENVIRONMENTAL IMPACT ANALYSIS (EIA)

INITIAL EXPLORATION PLAN 

Mississippi Canyon Block 720 (OCS-G 33170) 

Mississippi Canyon Block 721 (OCS-G 33171) 

Mississippi Canyon Block 722 (OCS-G 33172) 

Offshore Louisiana 

November 2012 

Prepared for: 

Shell Offshore Inc. 

P.O. Box 61933 

New Orleans, Louisiana 70161 

Telephone: (504) 425-6021 

Prepared by: 

CSA International, Inc. 

8502 SW Kansas Avenue 

Stuart, Florida 34997 

Telephone: (772) 219-3000 

Page 104 Public Information Copy
Introduction 

Project Summary 

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

Blocks 720, 721, and 722 (MC 720, 721, and 722) for eight exploration wells to be drilled using a 

dynamically positioned semisubmersible rig. This Initial EP is for proposed well locations A, B, C, 

and D in MC 721; E, F, and G in MC 720; and H in MC 722. 

The lease area is 49 miles (79 km) from the nearest shoreline, 108 miles (174 km) from the 

onshore support base at Port Fourchon, Louisiana, and 74 miles (119 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 3,125 to 3,747 ft 

(953 to 1,142 m). 

The Noble Jim Day, a dynamically positioned semisubmersible rig, or an equivalent rig will be 

used for drilling. Drilling of the wells is expected to commence during the second quarter of 

2013. The average time to drill a well will be approximately 165 days. 

Purpose of the EIA 

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

(OCSLA), 43 United States Code (U.S.C.) §§ 1331-1356, as well as regulations including 30 Code 

of Federal Regulations (CFR) 550.212(o) and 550.227. The EIA is a project- and site-specific 

analysis of Shell’s planned activities under this EP. 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 the BOEM will review this EIA and 

prepare a Site-Specific Environmental Assessment (SEA) for the project. This EIA complies with 

guidance provided in existing Notice to Lessees and Operators (NTLs) issued by the former 

Minerals Management Service (MMS) and BOEMRE, including NTL 2008-G04. 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 and/or BSEE, the EIA will refer to the former BOEMRE as BOEM when addressing NTLs 

issued by BOEMRE or MMS. 

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 included in the Initial EP. 

Page 105 Public Information Copy
The 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 Programmatic Environmental Impact Statement (EIS) for the OCS Oil and Gas Leasing 

Program (MMS, 2007a; BOEM 2012a) and in multi-lease-sale EISs for the Western, Central, and 

Eastern Gulf of Mexico Planning Areas (MMS, 2001, 2007b, 2008; BOEMRE, 2011; BOEM, 

2012b). 

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. 

OCS Regulatory Framework 

The regulatory framework for OCS activities in the Gulf of Mexico was summarized by 

MMS (2010). Under the OCSLA, the U.S. Department of the Interior (USDOI) is responsible for 

the administration of mineral exploration and development of the OCS. Within the USDOI, the 

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 Parts 250, 251, 252, 254, 256, 270, and 282. The BOEM 

offshore regulations are in 30 CFR Parts 550, 551, 552, 556, 559, 560, 570, 580, 581, 582, 

and 585. 

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. 

Page 106 Public Information Copy
Table 1. Notices to Lessees and Operators (NTLs) that are applicable to this Environmental 

Impact Analysis (EIA). 

NTL Title Summary

2012-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 worst case 

discharge (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 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 107 Public Information Copy
Oil Spill Prevention and Contingency Planning 

Shell submitted an update to the Gulf of Mexico Regional Oil Spill Response Plan (OSRP) to the 

BSEE as 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 meets the response planning requirements 

of the relevant coastal states and federal oil spill planning regulations. The OSRP includes 

information regarding Shell’s regional oil spill organization and dedicated response assets, 

potential spill risks, and local environmental sensitivities. The OSRP presents specific 

information on the response program that includes a description of personnel and equipment 

mobilization, the incident management team organization, and the strategies and tactics used 

to implement effective and sustained spill containment and recovery operations. 

EIA Organization 

The EIA is organized into Sections A through I corresponding to the information required by 

NTL 2008-G04, which provides guidance regarding information required by 30 CFR Part 550 for 

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

Section C (Impact Analysis). 

Page 108 Public Information Copy
A. Impact-Producing Factors 

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

Form MMS-142. An “X” indicates that an IPF could reasonably be expected to affect a certain 

resource, and a dash (--) indicates no impact or negligible impact. Where there may be an 

effect, an analysis is provided in Section C. Potential IPFs for the proposed activity are listed 

below and briefly discussed in the following subsections: 

1. Drilling rig presence (including noise and lights); 

2. Physical disturbance to the seafloor; 

3. Air pollutant emissions; 

4. Effluent discharges; 

5. Water intake; 

6. Onshore waste disposal; 

7. Marine debris; 

8. Support vessel and helicopter traffic; and 

9. Accidents. 

A.1 Drilling Rig Presence (including noise and lights) 

The wells will be drilled using the Noble Jim Day or a similar dynamically positioned 

semisubmersible rig. The rig will be on site for an estimated 165 days per well. 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. The physical presence of a drilling rig in the ocean can attract 

pelagic fishes and other marine life, as discussed in Section C.5.1. 

A semisubmersible rig maintains buoyancy using ballasted, watertight pontoons located below 

the sea surface. The operating deck is located above the tops of passing waves. Structural 

columns connect the pontoons and operating deck. When the rig moves its location, the 

pontoons are de-ballasted so that the rig can float on the sea surface. The Noble Jim Day uses 

thrusters to hold or adjust its position. 

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

including infrasonic frequencies in at least some cases (MMS, 2000). Drilling noise from 

semisubmersibles is not particularly intense and is strongest at low frequencies, averaging 

10 to 500 Hz (Richardson et al., 1995). From a semisubmersible, sound and vibration are 

transmitted to the water either through the air or the risers (MMS, 2000). Drilling rigs also 

maintain exterior lighting for navigational and aviation safety in accordance with federal 

regulations. 

Page 109 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)

Florida 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)

Page 110 Public Information Copy
Table 2 Footnotes and Applicability: 

(1) Activities that may affect a marine sanctuary or topographic feature. Specifically, if the well, platform site, or 

any anchors will be on the seafloor within the following: 

(a) 4-mi zone of the Flower Garden Banks, or the 3-mi zone of Stetson Bank; 

(b) 1,000-m, 1-mi, or 3-mi zone of any topographic feature (submarine bank) protected by the Topographic 

Features Stipulation attached to an Outer Continental Shelf (OCS) lease; 

(c) Essential Fish Habitat (EFH) criteria of 500 ft from any no-activity zone; or 

(d) Proximity of any submarine bank (500-ft buffer zone) with relief greater than 2 m that is not protected by 

the Topographic Features Stipulation attached to an OCS lease. 

 Not applicable. The lease is not within the given ranges (buffer zone) of any marine sanctuary, 

topographic feature, or no-activity zone. There are no submarine banks in the 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 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. A dynamically positioned semisubmersible rig will be 

used; therefore, no seafloor disturbances due to anchoring will occur. 

(5) Exploration or production activities where 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. The lease area is on the list of archaeology survey 

blocks (BOEM, 2012c). The archaeological survey detected 302 unidentified sonar contacts within the 

survey area. The distribution patterns and acoustic characteristics of these sonar targets indicate that 

they are modern debris primarily associated with industrial waste dumping or field development 

activities. The lease is beyond the 60-m depth contour, so prehistoric archaeological sites are not likely. 

A dynamically positioned 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, sea turtles, or their critical habitats 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. 

Page 111 Public Information Copy
A.2 Physical Disturbance to the Seafloor 

Semisubmersible rigs like the Noble Jim Day do not use anchors for holding or stabilization 

during drilling operations. 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, 

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 the drilling rig, as well as service vessels and helicopters. 

These emissions occur mainly from combustion of diesel fuel. The combustion of fuels occurs 

on diesel-powered generators, pumps, or motors and from lighter fuel motors. Primary air 

pollutants typically associated with OCS activities are suspended particulate matter (PM), sulfur 

oxides (SOx), nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon monoxide 

(CO). 

The Air Quality Emissions Report (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). 

A.4 Effluent Discharges 

Effluent discharges are summarized in EP Section 7. Support vessel discharges will be in 

accordance with USCG regulations and, as applicable, the National Pollutant Discharge 

Elimination System (NPDES) Vessel General Permit, and therefore are not expected to cause 

significant impacts on water quality. Discharges from the semisubmersible rig will be in 

compliance with and monitored as required by the NPDES permit (GMG290000). 

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. SBM cuttings will be 

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

with the NPDES permit limitations for SBM fluid retained on cuttings. The estimated volume of 

SBM cuttings to be discharged is provided in EP Section 7. 

Other effluent discharges in accordance with the NPDES permit may include excess cement, 

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

unit brine, uncontaminated fire water, and ballast water. 

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 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 

Page 112 Public Information Copy
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 2 million gallons of water per 

day, of which at least 25% is used for cooling purposes. The drilling rig does not trigger the 

cooling water intake permit requirements of the NPDES permit because it was constructed prior 

to the July 17, 2006, applicability date. 

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 the Republic/BFI landfill, 

Sorrento, Louisiana, or the parish landfill, Avondale, Louisiana. Recyclable trash and debris will 

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

Louisiana. Hazardous waste such as paints, solvents, and unused chemicals will be disposed of 

at Safety Kleen Systems, Inc., Denton, Texas, while used oil will be sent to Omega Waste 

Management for recycling. Universal waste including batteries, lamps, glass, and 

mercury-contaminated waste will be recycled at Lamp Environmental Industries, Hammond, 

Louisiana. At the 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) 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 shorebased facilities at Port Fourchon and Boothville, Louisiana, for 

onshore support for water and air transportation, respectively. No terminal expansion or 

construction is planned at either location. 

The supply base at Port Fourchon 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 

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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). 

A.9 Accidents 

A.9.1 Types of Accidents Evaluated 

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

10. a small fuel spill, which is the most likely type of spill during OCS development activities; and 

11. 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. 

The lease sale EIS (MMS, 2007b) analyzes three other types of accidents: chemical spills, vessel 

collisions, and loss of well control. These accidents are discussed briefly in Section A.9.4. 

A.9.2 Small Fuel Spill 

Spill Size. According to the analysis in 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, the duration of a small spill and the 

opportunity for impacts to occur would be very brief. 

The water-soluble fractions of diesel are dominated by two- and three-ringed polycyclic 

aromatic hydrocarbons (PAHs), which are moderately volatile (National Research Council [NRC], 

2003). The constituents of these oils are light to intermediate in molecular weight and can be 

readily degraded by aerobic microbial oxidation. Diesel’s density is such that it will not sink 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, 2003) and would 

not be expected to occur to any appreciable degree in offshore waters of the Gulf of Mexico. 

Diesel oil is readily and completely degraded by naturally occurring microbes (NOAA, 2006). 

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The fate of a small diesel fuel spill was estimated using NOAA’s Automated Data Inquiry for Oil 

Spills 2 (ADIOS2) model. This model uses the physical properties of oils in its database to predict 

the rate of evaporation and dispersion over time, as well as changes in the density, viscosity, 

and water content of the product spilled. It is estimated that over 90% of a small diesel spill 

would be evaporated or naturally dispersed within 24 hours. The area of the sea surface with 

diesel fuel on it would range from 1.2 to 12 ac (0.5 to 5 ha) depending on sea state and weather 

conditions. 

The ADIOS2 results, coupled with spill trajectory information discussed below for a large spill, 

indicate that a small fuel spill would not affect coastal or shoreline resources. The lease area 

(MC 720, 721, and 722) is approximately 49 miles (79 km) from the nearest coastline (Louisiana). 

Modeling results discussed below indicate that a spill in the lease area would have no shoreline 

contact within 3 days and a 4% probability of contacting the nearest Louisiana shoreline 

(Plaquemines Parish) within 10 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 Because 

of the distance of these potential spills on the OCS and the lack of persistence, it is unlikely that 

they 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 3929,000 bbl for the first day with a 30-day average of 

355,000 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, in terms of both initial and the sustained rates, has 

a low probability of being realized. Some of the factors that are likely to reduce rates and 

volumes, 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 

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area) are presented in Table 3. The OSRA results presented 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. The model predicts no shoreline contact within 3 days. After 10 days, three Louisiana 

parishes may be contacted. After 30 days, 11 counties and parishes, including 2 Texas counties, 

8 Louisiana parishes, and 1 Florida county may be contacted. Plaquemines Parish, Louisiana, has 

the greatest probability of shoreline contact, with a 4% and 8% chance within 10 and 30 days, 

respectively. 

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 Contacta

(%)

3 Days 10 Days 30 Days

C10 Galveston, Texas -- -- 1

C12 Jefferson, Texas -- -- 1

C13 Cameron, Louisiana -- -- 3

C14 Vermilion, Louisiana -- -- 2

C15 Iberia, Louisiana -- -- 1

C17 Terrebonne, Louisiana -- 1 3

C18 Lafourche, Louisiana -- 2 3

C19 Jefferson, Louisiana -- -- 1

C20 Plaquemines, Louisiana -- 4 8

C21 St. Bernard, Louisiana -- -- 1

C28 Okaloosa, Florida -- -- 1

a

 Conditional probability refers to the probability of contact within the stated time period, assuming that a spill has 

occurred (-- indicates less than 0.5%). 

The OSRA model does not evaluate the fate of a spill over time periods longer than 30 days, nor 

does it predict the fate of a release that continues over a period of weeks or months. Also as 

noted by Ji et al. (2004), the OSRA model does not take into account the chemical composition 

or biological weathering of oil spills, the spreading and splitting of oil spills, or spill response 

activities. The model does not assume a particular spill size but has generally been used by 

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, 2003). 

Weathering decreases the concentration of oil and produces changes in its chemical 

composition, physical properties, and toxicity. The more toxic, light aromatic and aliphatic 

hydrocarbons are lost rapidly by evaporation and dissolution from the slick on the water 

surface. Evaporated hydrocarbons are degraded rapidly by sunlight. Biodegradation of oil on 

the water surface and in the water column by marine bacteria removes first the n-alkanes and 

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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 (APD) is submitted and will include equipment and services available to Shell 

through MWCC’s development of near-term capability and other industry sources. Shell is a 

member of Clean Caribbean & Americas, Marine Spill Response Corporation, Clean Gulf 

Associates, and Oil Spill 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 EIS (MMS, 2007b) discusses three other types of accidents: chemical spills, vessel 

collisions, and loss of well control. These accidents are discussed briefly below. No hydrogen 

sulfide (H2S) is expected at this site, and no other site-specific issues have been identified for this 

EP. The analysis in the lease sale EIS 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 

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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). No significant impacts 

are expected from chemical spills. 

Vessel Collisions. As summarized in MMS (2007b) and BOEM (2012b), 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). 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 are 

considered to be a subset of more serious incidents with greater risk of oil spill or human injury 

(MMS, 2007b). Loss of well control may result in the release of oil. 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 on the continental slope in the northwestern Gulf of Mexico, 49 miles (79 km) 

from the nearest shoreline, 108 miles (174 km) from the onshore support base at 

Port Fourchon, Louisiana, and 74 miles (119 km) from the helicopter base at Boothville, 

Louisiana. 

The wellsites in MC 720, 721, and 722 are at a water depth of approximately 3,125 to 3,747 ft 

(953 to 1,142 m) (Figure 1b of EP). There is seafloor faulting within 2,000 ft (610 m) of well 

locations A, B, and C, but no high-density areas of chemosynthetic communities will be 

disturbed. The archaeological assessment and seafloor surveys (C&C Technologies, Inc., 2009; 

Geoscience Earth and Marine Services, Inc. [GEMS], 2010) reported three marine avoidance 

zones within 2,000 ft (610 m) of well location F. Other sonar contacts were identified as simple 

debris or possibly barrels and are not archaeologically significant. Shell’s procedure “Waste 

Barrel Avoidance and Release Response in the Mississippi Canyon Area,” which has been 

previously approved by MMS and BOEM, applies to operations that could cause a disturbance of 

a seafloor barrel. Shell’s over‐arching 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. According to the survey results, the proposed wellsite 

locations appear suitable for the planned activity. 

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A detailed description of the regional affected environment is provided in recent EISs 

(MMS 2007b; BOEM, 2012b), including meteorology, oceanography, geology, air and water 

quality, benthic communities, threatened and endangered species, biologically sensitive 

resources, archaeological resources, socioeconomic conditions, and other marine uses. These 

regional descriptions are based on extensive literature reviews and are incorporated by 

reference. General background information is presented below, and brief descriptions of each 

potentially affected resource are presented in Section C, including site-specific and/or new 

information if available. 

The local environment in the lease area is not known to be unique with respect to 

physical/chemical, biological, or socioeconomic conditions. Baseline environmental conditions 

in the lease area are expected to be consistent with the regional description of continental slope 

locations evaluated in recent lease sale EISs (MMS, 2001, 2007b, 2008; BOEMRE, 2011; BOEM, 

2012b,d).

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 multi-lease-sale EISs for the Western, Central, and 

Eastern Gulf of Mexico Planning Areas (MMS, 2001, 2007b, 2008) as well as the final EIS for the 

Western and Central Gulf of Mexico Planning Areas (BOEM, 2012b). 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 shorebased pollution sources, offshore air quality is expected to be 

good. The attainment status of federal OCS waters is unclassified because there is no provision 

in the Clean Air Act for classification of areas outside state waters (MMS, 2007b). 

In general, ambient air quality on coastal counties along the Gulf of Mexico is relatively good 

(BOEM, 2012a). As of July 20, 2012, 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, 2012). One coastal metropolitan area in Texas 

(Houston-Galveston-Brazoria) is a nonattainment area for 8-hour ozone. 

Winds in the region are driven by the clockwise circulation around the Bermuda High 

(MMS, 2007b). The Gulf of Mexico is located to the southwest of this center of circulation, 

resulting in a prevailing southeasterly to southerly flow, which is conducive to transporting 

emissions toward shore. However, circulation is also affected by tropical cyclones (hurricanes) 

during summer and fall and by extratropical cyclones (cold fronts) during winter. 

IPFs potentially affecting air quality are air pollutant emissions and two types of accidents: 

a small fuel spill and a large oil spill. 

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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. These emissions occur mainly from combustion or burning 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), 

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. 

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 EPis 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 (PSD) Class I air 

quality area. The BOEM coordinates with the National Park Service and the USFWS if emissions 

from proposed projects may affect the Breton Class I area. The lease area is approximately 

84 miles (135 km) from the Breton Wilderness Area. Shell does not anticipate impact on the 

Class I area but will comply with emissions requirements as directed by the BOEM. 

Impacts of a Small Fuel Spill 

Potential impacts of a small spill on air quality are expected to be consistent with those analyzed 

and discussed in recent EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b). 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 ADIOS2 model (see Section A.9.2) indicates that more than 90% of a small 

diesel spill would be evaporated or dispersed within 24 hours. The area of the sea surface with 

diesel fuel on it 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 recent EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b). 

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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 included in situ burning of the 

floating oil. Burning would generate a plume of black smoke and result in emissions of NOx, SOx, 

CO, and PM, as well as greenhouse gases. 

Due to the lease area location (49 miles [79 km] from the nearest shoreline), most air quality 

impacts would occur in offshore waters. Depending on the spill trajectory and the effectiveness 

of spill response measures, coastal air quality could also be affected. Based on the OSRA 

modeling predictions (Table 3), Plaquemines Parish, Louisiana, is the coastal area most likely to 

be affected. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

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 potentially affecting 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. 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 limitations and requirements will be met. After 

discharge, SBM retained on cuttings would be expected to adhere tightly to the cuttings 

particles and, consequently, would not produce much turbidity as the cuttings sink through the 

water column (Neff et al., 2000). There will be no persistent impacts on water quality in the 

lease area, according to analyses in the most recent Final EIS (BOEM, 2012b). 

Treated sanitary and domestic wastes may have a slight transient effect on water quality in the 

immediate vicinity of these discharges. NPDES permit limitations and requirements will be met 

and little or no impact on water quality is anticipated. Support vessel discharges will comply 

with USCG regulations and, as applicable, the NPDES Vessel General Permit, and therefore are 

not expected to cause significant impacts on water quality. 

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. 

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Other discharges such as desalination unit brine and uncontaminated cooling water, fire water, 

and ballast water are expected to be diluted rapidly and have little or no impact on water 

quality. 

Impacts of a Small Fuel Spill 

Potential impacts of a small spill on water quality are expected to be consistent with those 

analyzed and discussed in recent EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b). 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 the sea 

surface with diesel fuel on it 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, 2003). The constituents of these oils are light to intermediate in 

molecular weight and can be readily degraded by aerobic microbial oxidation. Diesel’s density is 

such that it will not sink and pool on the seafloor. Diesel dispersed in the water column can 

adhere to suspended sediments, but this generally occurs only in coastal areas with 

high-suspended solid loads (NRC, 2003) and would not be expected to occur to any appreciable 

degree in offshore waters of the Gulf of Mexico. Diesel oil is readily and completely degraded 

by naturally occurring microbes (NOAA, 2006). 

A small fuel spill would not affect coastal water quality because the spill would not be expected 

to make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill 

Potential impacts of a large oil spill on water quality are expected to be consistent with those 

analyzed and discussed in recent EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b). 

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). 

A report by Kujawinski et al. (2011) indicates that chemical components of subsea dispersants 

used during the Macondo spill persisted for up to two months and were detectable up to 

186 miles (300 km) from the wellsite at a water depth of 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 dispersant (BOEM, 2012d). 

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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, 2003). Marine water quality would be temporarily affected by the dissolved 

components and small oil droplets that do not rise to the surface or are mixed down by surface 

turbulence. Dispersion by currents and microbial degradation removes the oil from the water 

column or dilutes the constituents to background levels. 

A large oil spill could result in a release of gaseous hydrocarbons that could affect water quality. 

During the Macondo spill, large volumes of methane (CH4) were released, causing localized 

oxygen depletion as methanotrophic bacteria rapidly metabolized the hydrocarbons (Joye et al., 

2011; Kessler et al., 2011). However, a broader study of the deepwater Gulf of Mexico found 

that although some stations showed 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 (49 miles [79 km] from the nearest shoreline), most water quality 

impacts would occur in offshore waters. Depending on the spill trajectory and the effectiveness 

of spill response measures, coastal water quality could be affected. Based on the OSRA 

modeling predictions (Table 3), nearshore waters and embayments of Plaquemines Parish, 

Louisiana, are the most likely coastal areas 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 3,125 to 3,747 ft 

(953 to 1,142 m). See EP Section 6a for further information. 

According to the BOEM (2011), existing information for the deepwater Gulf of Mexico indicates 

that the seafloor is composed primarily of soft sediments; hard bottom communities are rare. 

MC 720, 721, and 722 are within deepwater Grid 13 where remotely operated vehicle (ROV) 

coverage of the seafloor is considered adequate to characterize the area (BOEM, 2011). 

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. Sediments 

at these two stations were predominantly clay (46% to 54%) and silt (43% to 45%). 

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Table 4. Benthic community data from stations near the lease area and in similar water depths 

sampled during the Northern Gulf of Mexico Continental Slope Habitats and Benthic 

Ecology Study (From: Wei, 2006; Rowe and Kennicutt, 2009). 

Station

Location 

Relative to 

Lease Area

Water 

Depth

(m)

Abundance

Meiofauna

(individuals/m2)

Macroinfauna

(individuals/m2)

Megafauna

(individuals/ha)

MT-3 20 mi NW 990 885,995 4,924 1,034

MT-4 29 mi S 1,401 246,058 3,262 1,548

Meiofaunal and megafaunal abundance from Rowe and Kennicutt (2009); macroinfaunal abundance from Wei (2006). 

Meiofauna (animals passing through a 0.5-mm sieve but retained on a 0.062-mm sieve) 

densities in water depths representative of the lease area typically range from about 

220,000 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 3,000 individuals/m2, lower than the values in Table 4. 

Polychaetes are typically the most abundant macroinfaunal group on the northern Gulf of 

Mexico continental slope, followed by amphipods, tanaids, bivalves, and isopods. Wei (2006) 

recognized four depth-dependent faunal zones (1 through 4), two of which are divided 

horizontally. The lease area is in Zone 2E, which consists of stations on the mid Texas-Louisiana 

Slope ranging in depth from 2,050 to 5,997 ft (625 to 1,828 m). The five most abundant species 

in Zone 2E are the polychaetes Litocorsa antennata, Aricidea suecica, Tharyx marioni, and 

Paralacydonia paradoxa and the bivalve Heterodonta sp. Megafaunal density from nearby 

stations MT-3 and MT-4 was 1,034 and 1,548 individuals/ha, respectively (Table 4). Densities of 

200 to 3,000 individuals/ha were reported from other stations in a similar depth range. 

Common megafauna included motile groups such as decapods, ophiuroids, holothurians, and 

demersal fishes, as well as sessile groups such as sponges and anemones. 

Bacteria are 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 2 grams of carbon 

per square meter (g C m−

2

) in the top 6 in. (15 cm) of sediments (Rowe and Kennicutt, 2009). 

IPFs potentially affecting 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, dynamically positioned 

semisubmersibles disturb the seafloor only around the wellbore (surface hole location) where 

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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 a dynamically positioned 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. 

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 eight surface locations in this exploration drilling 

program, the total impact area would be 1,553 ac (628 ha). 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 

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 

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sediments (silts and clays) could be resuspended for more than 30 days and dispersed over a 

much wider area. Previous studies characterized surface sediments in the vicinity of the site as 

about 50% clay and 45% silt (Rowe and Kennicutt, 2009). 

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect 

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical 

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill 

location. However, during the Macondo spill, subsurface plumes were reported at a water 

depth of about 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 two 

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 by MMS (2007a, 2008), depending on its extent, trajectory, and persistence. This 

contact could result in smothering and/or toxicity to benthic organisms. The affected area 

would be recolonized by benthic organisms over a period of months to years (NRC, 2003). 

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 by 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). These 

communities occur almost exclusively on authigenic carbonates created by chemosynthetic 

communities, and on shipwrecks. The nearest known chemosynthetic community site is located 

approximately 49 miles (79 km) west southwest of the lease area in MC 969 (Brooks et al., 

2009). 

The chemosynthetic community assessment by C&C Technologies (2009) and GEMS (2010) did 

not identify features that could support high-density deepwater benthic communities within 

2,000 ft (610 m) of the proposed drilling mud/cuttings discharge locations. 

IPFs potentially affecting high-density deepwater benthic communities are effluent discharges 

(drilling mud and cuttings), and a large oil spill from a well blowout at the seafloor. A small fuel 

spill would not affect benthic communities because the diesel fuel would float and dissipate on 

the sea surface. 

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Impacts of Effluent Discharges 

The chemosynthetic community assessment included in this EP, based on the reports by 

C&C Technologies (2009) and GEMS (2010), did not identify features that could support 

high-density deepwater benthic communities within 2,000 ft (610 m) of the proposed drilling 

mud/cuttings discharge locations. Monitoring programs on the Gulf of Mexico continental slope 

have shown that benthic impacts from drilling discharges typically are concentrated within 

about 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). If high-density 

deepwater communities are associated with the more distant expulsion features and mud 

volcanoes identified in the hazards survey, significant impacts on these communities will be 

avoided because of the distance from the discharge location. 

Impacts of a Large Oil Spill 

Previous analyses (MMS, 2007a, 2008b) 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 two 

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 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 by MMS (2007a, 2008), depending on its extent, trajectory, and 

persistence. Potential impacts on sensitive resources would be an integral part of the decision 

and approval process for the use of dispersants. The chemosynthetic community assessment by 

C&C Technologies (2009) and GEMS (2010) 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 by MMS (2007b), impacts could include loss of habitat, biodiversity, and live coral 

coverage; destruction of hard substrate; change in sediment characteristics; and reduction or 

loss of one or more commercial and recreational fishery habitats. Sublethal effects could be 

long lasting and affect the resilience of coral colonies to natural disturbances (e.g., elevated 

water temperature and diseases) (BOEM 2012d). 

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) 

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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., 2012). 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., 2012). The study location is about 51 miles 

(83 km) northeast of the activities discussed in this EIA. There would not likely be cumulative 

impacts to those corals even in the unlikely event of a large spill associated with the activities 

discussed in this EIA.

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 blocks are 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

West Delta Area, South Addition 147, located 34 miles (55 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. 

C.2.4 Pinnacle Trend Area Live Bottoms 

The lease area is not covered by the Live Bottom (Pinnacle Trend) Stipulation. As defined by 

NTL 2009-G39, the nearest pinnacle trend blocks are located about 81 miles (131 km) 

north-northeast of the lease area, along the shelf edge south of Alabama. 

There are no IPFs associated with either routine operations or accidents that could cause 

impacts to pinnacle trend area live bottoms due to the distance from the lease area. 

C.2.5 Eastern Gulf Live Bottoms 

The lease area is not covered by the Live Bottom (Low-Relief) Stipulation, which applies to 

Eastern Gulf of Mexico Planning Area leases in water depths of 328 ft (100 m) or less. The 

nearest blocks covered by the live bottom stipulation, as defined by NTL 2009-G39, are about 

117 miles (188 km) northeast of the project area. 

There are no IPFs associated with either routine operations or accidents that could cause 

impacts to eastern Gulf live bottom areas due to the distance from the lease area. 

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C.3 Threatened, Endangered, and Protected Species and Critical Habitat 

This section discusses species listed as endangered or threatened under the ESA. In addition, it 

includes all marine mammal species in the region, which are protected under the MMPA. 

Endangered or threatened species that may occur in the project area and/or along the northern 

Gulf Coast are listed in Table 5. The table also indicates the location of 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 Florida manatee. These two 

agencies share federal jurisdiction over sea turtles, with NMFS having lead responsibility at sea 

and USFWS on nesting beaches. 

The sperm whale and five species of sea turtles are the only endangered or threatened species 

likely to occur at or near the lease area. No critical habitat has been designated for these 

species in the Gulf of Mexico. 

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right 

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare 

or extralimital there (Würsig et al., 2000). No critical habitat has been designated for these 

species in the Gulf of Mexico. 

Coastal endangered or threatened species include the Florida manatee, Piping Plover, 

Whooping Crane, Gulf sturgeon, and four subspecies of beach mouse. Critical habitat has been 

designated for all of these species as indicated in Table 5 and discussed in individual sections. 

Table 5. Federally listed endangered and threatened species in the lease area and along the 

northern Gulf Coast. 

Species Scientific Name Status

Potential 

Presence Critical Habitat 

Designated in

Gulf of Mexico Lease 

Area Coastal

Marine Mammals

Sperm whale Physeter macrocephalus E X -- None

Florida manatee Trichechus manatus 

latirostris

E -- X

Florida 

(Peninsular)

Blue whale Balaenoptera musculus E X

a

-- None

Fin whale Balaenoptera physalus E X

a

-- None

Humpback whale Megaptera novaeangliae E X

a

-- None

North Atlantic right whale Eubalaena glacialis E X

a

-- None

Sei whale Balaenoptera borealis E X

a

-- None

Sea Turtles

Loggerhead turtle Caretta caretta T, EbX X None

Green turtle Chelonia mydas T, EcX X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempii E X X None

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Species Scientific Name Status

Potential 

Presence Critical Habitat 

Designated in

Gulf of Mexico Lease 

Area Coastal

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 FR 58868; 

September 22, 2011). 

c

 The green sea turtle is threatened, except for the Florida breeding population, which is listed as endangered. 

Two other coastal species (Bald Eagle and Brown Pelican) discussed by MMS (2007b) and 

BOEM (2012b) are no longer 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 

(Microtus pennsylvanicus dukecampbelli) are remote from the lease area and highly unlikely to 

be affected. 

C.3.1 Sperm Whale (Endangered) 

The only endangered marine mammal likely to be present at or near the project area is the 

sperm whale (Physeter macrocephalus). Resident populations of sperm whales occur within the 

Gulf of Mexico. A species description is presented in a recent lease sale EIS (MMS, 2007b). Gulf 

of Mexico sperm whales are classified as an endangered species and a “strategic stock” (defined 

as a stock that may have unsustainable human-caused impacts) by NMFS (Waring et al., 2012). 

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 

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(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 (SWSS) consisted of mixed-sex groups comprising adult females and immatures, 

and groups of bachelor males. Typical group size for mixed groups was 10 individuals 

(Jochens et al., 2008). SWSS results show that sperm whales transit through the vicinity of the 

lease area. Movements of satellite-tracked individuals suggest that this area of the Gulf 

continental slope is within the home range of the Gulf of Mexico population (within the 

95% utilization distribution) (Jochens et al., 2008). 

IPFs potentially affecting sperm whales include 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 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 

Noise from routine drilling activities has the potential to disturb sperm whales. Sperm whales 

appear to have good low-frequency hearing, but the available data do not indicate a consistent 

response to anthropogenic noise (Jochens et al., 2008). Noise associated with drilling is 

relatively weak in intensity, and an individual animal’s noise exposure would be transient. There 

are other OCS facilities and activities near the lease area, and the region as a whole has a large 

number of similar sources. Due to the limited scope, timing, and geographic location of drilling 

activities, this project would represent a small temporary contribution to the overall noise 

regime. 

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 recent lease sale 

EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b) did not identify these as IPFs for sperm 

whales. Therefore, no significant impacts are expected. 

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 

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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 three 

(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 recent EISs 

(MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b) 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 

Shell’s OSRP will mitigate and reduce the potential for impacts on sperm whales. EP Section 9b

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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 over 90% would be evaporated or dispersed naturally 

within 24 hours. The area of the sea surface with diesel fuel on it would range from 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 would be expected. 

Impacts of a Large Oil Spill 

Potential spill impacts on marine mammals including sperm whales are discussed in recent EISs 

(MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012a,b) and by the 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. 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).

Studies have shown that the cetacean epidermis functions as an effective barrier to noxious 

substances found in petroleum (Geraci and St. Aubin, 1985). Unlike other mammals, 

penetration of such substances in cetacean skin is impeded by tight intercellular bridges, the 

vitality of the superficial cells, the thickness of the epidermis, and the lack of sweat glands and 

hair follicles. In addition, cetacean skin is free from hair or fur, which in other marine mammals 

not found in the Gulf of Mexico (e.g., pinnipeds and otters) tend to collect oil and/or tar. 

In the event of a large spill, the level of vessel and aircraft activity associated with spill response 

could disturb sperm whales and potentially result in vessel strikes, entanglement, or other injury 

or stress. Response vessels would operate in accordance with NTL 2012-JOINT-G01 to reduce 

the potential for striking or disturbing these animals. 

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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 sperm whales are expected. 

C.3.2 Florida 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 a recent lease sale EIS (MMS, 2007b) 

and in the recovery plan for this species (USFWS, 2001). 

IPFs potentially affecting manatees include support vessel and helicopter traffic and a large oil 

spill. A small fuel spill in the lease area would be unlikely to affect manatees, as the lease area is 

approximately 49 miles (79 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 spill within 10 to 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. 

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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).

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) also have been reported from the Gulf of Mexico but are considered rare 

or extralimital there (Würsig et al., 2000). No critical habitat has been designated for these 

species in the Gulf of Mexico. 

Due to the rare occurrence of these whales in the Gulf of Mexico, 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 recent lease sale EISs (MMS, 2007b, 2008; 

BOEMRE, 2011; 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 below in 

Section C.3.4. 

C.3.4 Non-Endangered Marine Mammals (Protected) 

In addition to the seven endangered species that have been cited previously, 22 additional 

species of marine mammals 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 

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such as the pantropical spotted dolphin, spinner dolphin, and Clymene dolphin. A brief 

summary is presented below, and additional information on these groups is presented in a 

recent lease sale EIS (MMS, 2007b). 

Mysticete whales. Two species of non-endangered mysticete whales are known from the Gulf 

of Mexico: Bryde’s whale (Balaenoptera edeni) and minke whale (Balaenoptera acutorostrata). 

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., 2012). 

Either species could occur in the lease area. 

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., 2012). 

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., 2012). 

IPFs potentially affecting 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 

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. 

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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. 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 recent lease 

sale EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012a,b,d). 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).

Impacts of a Small Fuel Spill 

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b, 2008; 

BOEMRE, 2011; BOEM, 2012b), and oil impacts on marine mammals in general 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 fuel 

transfer. In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate 

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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, the duration of a small 

spill and opportunity for impacts to occur would be very brief. 

A small fuel spill in offshore waters would produce a slick on the water surface and increase the 

concentrations of petroleum hydrocarbons and their degradation products. The extent and 

persistence of impacts would depend on the meteorological and oceanographic conditions at 

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally 

within 24 hours. The area of the sea surface with diesel fuel on it would range from 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 recent EISs (MMS, 2007b, 2008; 

BOEMRE, 2011; BOEM, 2012b) and by 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 a recent lease sale EIS 

(MMS, 2007b). 

Leatherbacks and loggerheads are the most likely species to be present near the lease area as 

adults. Green, hawksbill, and Kemp’s ridley turtles are typically inner shelf and nearshore 

species, unlikely to occur near the lease area as adults. Hatchlings or juveniles of any of the sea 

turtles may be present in deepwater areas, including the lease area, where they may be 

associated with Sargassum and other flotsam. 

All five sea turtle species in the Gulf of Mexico are migratory and use different marine habitats 

according to their life stage. These habitats include high-energy beaches for nesting females 

and emerging hatchlings and pelagic convergence zones for hatchling and juvenile turtles. As 

adults, green, hawksbill, and loggerhead turtles forage primarily in shallow, benthic habitats. 

Leatherbacks are the most pelagic of the sea turtles, feeding primarily on jellyfish. 

Sea turtle nesting in the northern Gulf of Mexico can be summarized by species as follows: 

12. Loggerhead turtles – Loggerheads nest in significant numbers along the Florida Panhandle 

and, to a lesser extent, from Texas through Alabama (MMS, 2007b). The nearest significant 

nesting area of loggerhead turtles is found in Louisiana, on beaches within the Breton NWR; 

13. Green and leatherback turtles – Green and leatherback turtles infrequently nest on Florida 

Panhandle beaches (Florida Fish and Wildlife Conservation Commission, 2011); 

14. Kemp’s ridley turtles – The main Kemp’s ridley nesting site 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 

Kemp’s ridleys nesting in Alabama (Share the Beach, 2010); and

15. Hawksbill turtles – Hawksbills typically do not nest anywhere near the project area. 

IPFs potentially affecting 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 

Page 139 Public Information Copy
(Lohoefener et al., 1990) and, thus, may be more susceptible to impacts from sounds produced 

during routine operations. Helicopters and service vessels may also affect sea turtles due to 

machinery noise and/or visual disturbances. The most likely impacts would be short-term 

behavioral changes such as diving and evasive swimming, disruption of activities, or departure 

from the area. Due to the limited scope, 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. 

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). 

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 recent EISs (MMS, 2007b, 2008; BOEMRE, 

2011; BOEM, 2012b) and by the NMFS (2007) in its Biological Opinion for the Five-Year Oil and 

Gas Leasing Program in the Central and Western Planning Areas of the Gulf of Mexico. For this 

EP, there are no unique site-specific issues with respect to spill impacts on these animals. 

The probability of a fuel spill will be minimized by Shell’s preventative measures during fuel 

transfer. In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate 

and reduce the potential for impacts on sea turtles. 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 

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the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally 

within 24 hours. The area of the sea surface with diesel fuel on it would range from 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; BOEMRE, 2011; 

BOEM, 2012b). 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 49 miles (79 km) from the nearest shoreline (Louisiana). As explained in 

Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters 

prior to breaking up. 

Impacts of a Large Oil Spill 

Impacts of oil spills on sea turtles can include direct impacts from oil exposure, as well as 

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and 

dispersants). Direct physical and physiological effects can include skin irritation, inflammation, 

or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of toxic fumes and 

smoke (e.g., from in situ burning of oil); ingestion of oil (and dispersants) directly or via 

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 10 to 30 days. The nearest nesting area of loggerhead turtles 

is found in St. Bernard Parish, Louisiana, on beaches within the Breton NWR. Loggerhead turtles 

also nest to a lesser extent in Okaloosa County, Florida. Both these areas have contact 

probabilities of 1% after 30 days. 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). 

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In the event of a large spill, the level of vessel and aircraft activity associated with spill response 

could disturb sea turtles and potentially result in vessel strikes, entanglement, or other injury or 

stress. Response vessels would operate in accordance with NTL 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 sea turtles are expected. 

C.3.6 Piping Plover (Threatened) 

The Piping Plover (Charadrius melodus) is a migratory shorebird that overwinters along the 

southeastern U.S. and Gulf of Mexico coasts. This threatened species is in decline as a result of 

hunting, habitat loss and modification, predation, and disease (USFWS, 2003). Critical 

overwintering habitat has been designated, including beaches in Texas, Louisiana, Mississippi, 

Alabama, and Florida (Figure 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 a 

recent lease sale EIS (MMS, 2007b). 

A large oil spill is the only IPF potentially affecting Piping Plovers. There are no IPFs associated 

with routine project activities that could affect these birds. A small fuel spill in the lease area 

would be unlikely to affect Piping Plovers because a small fuel spill would not be expected to 

make landfall or reach coastal waters prior to breaking up (see explanation in Section A.9.2).

Impacts of a Large Oil Spill 

The lease area is 52 miles (83 km) from the nearest shoreline inhabited by Piping Plovers. The 

OSRA results summarized in Table 3 predict that Texas and Louisiana shorelines designated as 

critical habitat for the wintering Piping Plover could be contacted by a spill within 10 to 30 days. 

Plaquemines Parish, Louisiana, which has the highest probability of contact for the 10- and 

30-day intervals (4% and 8%, respectively), includes Piping Plover critical habitat. 

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. 

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Figure 1. Location of selected environmental features in relation to the lease area. 

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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, 2012). A non-migrating 

population has been re-introduced in central Florida, and another re-introduced population 

summers in Wisconsin and migrates to the southeastern U.S. for the winter. Whooping Cranes 

breed, migrate, winter, and forage in a variety of habitats, including coastal marshes and 

estuaries, inland marshes, lakes, ponds, wet meadows and rivers, and agricultural fields (USFWS, 

2007). About 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 recent lease sale EISs 

(MMS, 2007b; BOEM, 2012b).

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 is has a low probability of affecting Whooping Cranes because the lease area is 

approximately 444 miles (714 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. 

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 

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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 a recent lease sale 

EIS (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 potentially affecting 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 recent EISs (MMS, 2007b, 2008; 

BOEMRE, 2011; BOEM, 2012b) and by the NMFS (2007) in its Biological Opinion for the Five-Year 

Oil and Gas Leasing Program in the Central and Western Planning Areas of the Gulf of Mexico. 

For this EP, there are no unique site-specific issues with respect to this species. 

The lease area is about 115 miles (185 km) from the nearest Gulf sturgeon critical habitat. 

OSRA modeling (Table 3) predicts that a spill in the lease area has a 1% probability of contacting 

the coastal areas inhabited by Gulf sturgeon within 30 days. 

In the event of oil reaching Gulf sturgeon habitat, the fish could be affected by direct ingestion, 

ingestion of oiled prey, or the absorption of dissolved petroleum products through the gills. 

Based on the life history of this species, subadult and adult Gulf sturgeon would be most 

vulnerable to 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 

subspecies; Figure 1 shows the critical habitat combined for all four subspecies. Species 

descriptions are provided in a recent lease sale EIS (MMS, 2007b). 

A large oil spill is the only IPF potentially affecting subspecies of beach mouse. There are no IPFs 

associated with routine project activities that could affect these animals due to the distance 

from shore and the lack of onshore support activities near their habitat. 

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Impacts of a Large Oil Spill 

Potential spill impacts on beach mice are discussed in recent EISs (MMS, 2007b, 2008; BOEMRE, 

2011; BOEM, 2012b). For this EP, there are no unique site-specific issues with respect to these 

species. 

The lease area is about 153 miles (246 km) from the nearest beach mouse critical habitat. 

OSRA modeling predicts that a spill in the lease area would not contact beach mouse critical 

habitat 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. 

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. 

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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 potentially affecting 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 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). On the other hand, offshore structures are suitable stopover habitats for most 

trans-Gulf migrant species, and most of the migrants that stop over on platforms probably 

benefit from their stay, particularly in spring (Russell, 2005). 

A study in the North Sea indicated that platform lighting causes circling behavior in various 

birds, especially on cloudy nights; apparently the birds’ geomagnetic compass is upset by the 

red part of the spectrum from the lights currently in use (Poot et al., 2008). The numbers varied 

greatly, from none at all to some tens of thousands of birds per night per platform, with an 

apparent effect radius of up to 3 miles (5 km). A study in the Gulf of Mexico also noted the 

phenomenon, but did not recommend mitigation (Russell, 2005). Factors to consider in 

evaluating this impact in the Gulf of Mexico would include the lower incidence of cloudy and 

foggy days in the Gulf of Mexico versus the North Sea. Impacts on populations of either 

seabirds or trans-Gulf migrant birds may be adverse but are not expected to be significant 

(BOEM, 2012b). 

Impacts of Support Vessel and Helicopter Traffic 

Support vessels and helicopters are unlikely to significantly disturb pelagic birds in open, 

offshore waters. It is likely that individual birds would experience, at most, only short-term 

behavioral disruption, and the impact would not be significant. 

Impacts of a Small Fuel Spill 

Potential spill impacts on marine birds are discussed in recent EISs (MMS, 2007b, 2008; 

BOEMRE, 2011; BOEM, 2012b). For this EP, there are no unique site-specific issues with respect 

to spill impacts on these animals. 

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The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations including fuel transfer. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the potential for impacts on marine and pelagic birds. 

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 over 90% would be evaporated or dispersed naturally 

within 24 hours. The area of the sea surface with diesel fuel on it would range from 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 

toxic fumes. Due to the limited areal extent and short duration of water quality impacts from a 

small fuel spill, secondary impacts due to ingestion of oil via contaminated prey or reductions in 

prey abundance are unlikely. Due to the low densities of birds in open ocean areas, the small 

area affected, and the brief duration of the surface slick, no significant impacts on marine and 

pelagic birds would be expected. 

Impacts of a Large Oil Spill 

Potential spill impacts on marine and pelagic birds are discussed in recent EISs (MMS, 2007b, 

2008; BOEMRE, 2011; BOEM, 2012b). 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) have been 

discussed previously in Section C.3. Various species of non-endangered birds are also found 

along the northern Gulf Coast, including diving birds, shorebirds, marsh birds, wading birds, and 

waterfowl. Gulf Coast marshes and beaches also provide important feeding grounds and 

nesting habitats. Species that breed on beaches, flats, dunes, bars, barrier islands, and similar 

habitats include the Sandwich Tern, Wilson’s Plover, Black Skimmer, Forster’s Tern, Gull-Billed 

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Tern, Laughing Gull, Least Tern, and Royal Tern (USFWS, 2010b). Additional information is 

presented in recent lease sale EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b).

The Brown Pelican (Pelecanus occidentalis) was delisted from federal endangered status in 2009 

(USFWS, 2010c). However, this species is listed as a species of greatest conservation need by 

the State of Mississippi (Mississippi Department of Wildlife, Fisheries and Parks, 2011) and as a 

species of special concern by the State of Florida (Florida Fish and Wildlife Conservation 

Commission, 2011). Brown Pelicans inhabit coastal habitats and forage within both coastal 

waters and waters of the inner continental shelf. Aerial and shipboard surveys, including 

GulfCet and GulfCet II, indicate that Brown Pelicans do not occur over deep offshore waters 

(Fritts and Reynolds, 1981; Peake, 1996; Hess and Ribic, 2000). Nearly half the southeastern 

population of Brown Pelicans lives in the northern Gulf Coast, generally nesting on protected 

islands (USFWS, 2010b). 

IPFs potentially affecting shorebirds and coastal nesting birds include support vessel and 

helicopter traffic and a large oil spill. 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, timing, and geographic extent of drilling activities, any short-term impacts are not 

expected to be biologically significant to coastal bird populations. 

Aircraft traffic can cause some disturbance to birds onshore and offshore. Responses are highly 

dependent on the type of aircraft, the bird species, the activities that animals were previously 

engaged in, and previous exposures to overflights (Efroymson et al., 2000). Helicopters seem to 

cause the most intense responses over other human disturbances for some species (Bélanger 

and Bédard, 1989). However, Federal Aviation Administration Advisory Circular No. 91-36D 

recommends that pilots maintain a minimum altitude of 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 (Efroymson et al., 2000). With these 

guidelines in effect, it is likely that individual birds would experience, at most, only short-term 

behavioral disruption. 

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Impacts of Large Oil Spill 

The OSRA results summarized in Table 3 predict that shorelines of Texas and Louisiana that 

include habitat for shorebirds and coastal nesting birds could be affected within 30 days. 

The Macondo spill provides additional information regarding impacts on species of coastal and 

shorebirds that may be affected in the event that a large oil spill reached 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). Impacts to birds from the 

Macondo spill are being studied as part of the Natural Resource Damage Assessment, but results 

have not yet been released. Antonio et al. (2011) modeled bird mortality from the Macondo 

spill showing cumulative carcass numbers and mortality rate increasing exponentially from the 

start of the Macondo spill until the mortality rate began to decline after the 97th day of the spill. 

Note that the collected animals are a small subset of the total number of impacted birds; 

therefore, they represent an underestimate of the overall impact of the Macondo spill 

(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 

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 mid-water 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 potentially affecting 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. 

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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 limitations 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 

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, fracturing fluids, 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. Construction of the rig planned for use in this EP, the 

Noble Jim Day, started prior to July 17, 2006, and therefore it is not subject to the cooling water 

intake permit requirements of NPDES Permit GMG290000 . If a different rig is selected, it will 

also comply with applicable NPDES requirements. 

Impacts of a Small Fuel Spill 

Potential spill impacts on fisheries resources are discussed in recent EISs (MMS, 2007b, 2008; 

BOEMRE, 2011; BOEM, 2012a,b). For this EP, there are no unique site-specific issues with 

respect to spill impacts. 

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The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations including fuel transfer. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the potential for impacts on 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 over 90% would be evaporated or dispersed naturally 

within 24 hours. The area of the sea surface with diesel fuel on it would range from 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 

A large oil spill could affect water column biota including phytoplankton, zooplankton, 

ichthyoplankton, and nekton. A large spill that persisted for weeks or months would be more 

likely to affect these communities. While adult and juvenile fishes may actively avoid a large 

spill, planktonic eggs and larvae would be unable to avoid contact. Eggs and larvae of fishes 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 

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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 35 miles (57 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, 2009): 

16. Atlantic bluefin tuna (spawning, 

eggs, larvae, adults) 

17. Atlantic skipjack tuna (spawning, 

adults) 

18. Atlantic yellowfin tuna (spawning, 

juveniles, adults) 

19. Bigeye tuna (juveniles) 

20. Atlantic swordfish (larvae, juveniles, 

adults) 

21. Blue marlin (juveniles, adults) 

22. White marlin (juveniles, adults) 

23. Longbill spearfish (juveniles, adults) 

24. Oceanic whitetip shark (all) 

25. Shortfin mako shark (all) 

26. Silky shark (all) 

27. Longfin mako shark (all) 

28. Bigeye thresher shark (all) 

29. Whale shark (all) 

Research indicates the central and western Gulf of Mexico may be important spawning habitat 

for Atlantic bluefin tuna, and NMFS (2009) has designated a Habitat Area of Particular Concern 

(HAPC) for this species. The HAPC covers much of the deepwater Gulf of Mexico, including the 

lease area (Figure 1). The areal extent of the HAPC is approximately 15,000 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, 2009). 

Other HAPCs have been identified in the Gulf of Mexico by the GMFMC (2005). These include 

the Florida Middle Grounds, Madison-Swanson Marine Reserve, Tortugas North and South 

Ecological Reserves, Pulley Ridge, and several individual reefs and banks of the northwestern 

Gulf of Mexico (Figure 1). The nearest of these is Jakkula Bank, located 147 miles (236 km) west 

of the lease area. 

Routine IPFs potentially affecting 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. 

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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, 

fracturing fluids, and ballast water. Impacts on water quality have been discussed previously. 

No significant impacts on EFH for highly migratory pelagic fishes are expected from these 

discharges. 

Impacts of Water Intakes 

As noted previously, cooling water intake will cause entrainment and impingement of plankton, 

including fish eggs and larvae (ichthyoplankton). Due to the limited scope, 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 

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. 

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008; BOEMRE, 2011; 

BOEM, 2012a,b). For this EP, there are no unique site-specific issues with respect to spill 

impacts. 

A small fuel spill in offshore waters would produce a slick on the water surface and increase the 

concentrations of petroleum hydrocarbons and their degradation products. The extent and 

persistence of impacts would depend on the meteorological and oceanographic conditions at 

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally 

within 24 hours. The area of the sea surface with diesel fuel on it would range from 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 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 114,793 mi2 

(297,312 km2) of the Gulf of Mexico. 

A small fuel spill would not affect EFH for corals and coral reefs; the nearest coral EFH is 

Sackett Bank, located 35 miles (57 km) northwest of the lease area. A small fuel spill would float 

and dissipate on the sea surface and would not contact these features. 

Impacts of a Large Oil Spill 

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008; BOEMRE, 2011; 

BOEM, 2012a,b). For this EP, there are no unique site-specific issues with respect to EFH. 

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An oil spill in offshore waters would temporarily increase hydrocarbon concentrations on the 

water surface and potentially the subsurface as well. Given the extent of EFH designations in 

the Gulf of Mexico (GMFMC, 2005; NMFS, 2009), some impact on EFH would be unavoidable. 

A large spill could affect the EFH for many managed species including shrimps, stone crab, spiny 

lobster, 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, 2009). A large spill 

could temporarily degrade the HAPC due to increased hydrocarbon concentrations in the water 

column, with the potential for lethal or sublethal impacts on spawning tuna 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, 2009). 

The nearest feature designated as EFH for corals is located 35 miles (57 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 720, 721, and 722 are on the list of archaeological survey blocks (BOEM, 2012c). The 

archaeological survey conducted by C&C Technologies (2009) detected unidentified sonar 

targets within the survey areas that were classified as modern debris and are not recommended 

for investigation or avoidance of the basis of archaeological potential. 

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 

There are no known historic shipwrecks in the lease area and a large oil spill would not result in 

any impact on archaeological resources. 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 10 to 30 days. 

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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. 

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 by MMS (2007b), 

should an oil spill contact a coastal historic site, such as a fort or a lighthouse, the major impact 

would be a temporary, reversible visual impact from oil contact and contamination of the site 

and its environment. However, more recent studies suggest that the impacts could be longer 

term and not easily reversible (BOEM, 2012b). 

C.6.2 Prehistoric Archaeological Sites 

With water depths ranging from approximately 3,125 to 3,747 ft (953 to 1,142 m), the wellsites 

are well beyond the 197-ft (60-m) depth contour used by the BOEM as the seaward extent for 

prehistoric archaeological site potential in the Gulf of Mexico. Because prehistoric 

archaeological sites are not found in the lease area, the only relevant IPF is a large oil spill that 

would reach coastal waters within the 197-ft (60-m) depth contour. 

Impacts of a Large Oil Spill 

Because prehistoric archaeological sites are not found in the lease area, they would not be 

affected by the physical effects of a subsea blowout. The MMS (2007b) estimates that a severe 

subsurface blowout could resuspend and disperse sediments within a 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 10 to 30 days. A spill reaching a prehistoric site along these shorelines could 

coat fragile artifacts or site features and compromise the potential for radiocarbon dating 

organic materials in a site (although other dating methods are available and it is possible to 

decontaminate an oiled sample for radiocarbon dating). Coastal prehistoric sites could also be 

damaged by spill cleanup operations (e.g., by destroying fragile artifacts and disturbing the 

provenance of artifacts and site features). 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

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. 

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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 recent EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012a,b,d) 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 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 are not located in a wildlife refuge or a wilderness area. Potential impacts of support 

vessel traffic are briefly addressed below. 

A small fuel spill in the lease area would be unlikely to affect coastal habitats 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. 

Impacts of a Large Oil Spill 

Potential spill impacts on coastal habitats are discussed in recent EISs (MMS, 2007b, 2008; 

BOEMRE, 2011; 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. Plaquemines Parish, Louisiana, has the highest probability of 

contact for the 10- and 30-day intervals (4% and 8%, respectively). After 30 days, 11 counties or 

parishes may be contacted from Galveston, Texas, to Okaloosa, 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 EIS (MMS, 2007b) and Shell’s OSRP. Coastal wildlife refuges, 

wilderness areas, and state and national parks within the geographic range of the potential 

shoreline contacts after 30 days include the following: 

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30. Brazoria NWR 

31. Galveston Island State Park (SP) 

32. Apffel Park 

33. Seawolf Park 

34. Old Fort Travis Park 

35. Atkinson Island Wildlife Management 

Area (WMA) 

36. Fort Anahuac Park 

37. Anahuac NWR 

38. McFaddin NWR 

39. Candy Abshier WMA 

40. Atkinson Island WMA 

41. Sea Rim SP 

42. Murphree WMA 

43. Texas Point NWR 

44. Sabine NWR 

45. Cameron Prairie NWR 

46. Lacassine NWR 

47. Little Pecan Island Natural Area (NA) 

48. Peveto Woods NA 

49. Lower Neches WMA 

50. Rockefeller WMA 

51. Paul J. Rainey WMA 

52. Marsh Island WMA 

53. Cypremort Point SP 

54. Shell Keys NWR 

55. Atchafalaya Delta WMA 

56. Mandalay NWR 

57. Isles Dernieres Barrier Islands Refuge 

58. Pointe au Chien WMA 

59. Wisner WMA 

60. Grand Isle SP 

61. Salvador WMA 

62. Jean Lafitte National Historical Park 

and Preserve 

63. Lafitte Woods NA 

64. Delta NWR 

65. Pass A Loutre WMA 

66. Breton NWR 

67. St. Bernard SP 

68. Biloxi WMA 

69. Bayou Sauvage NWR 

70. Gulf Islands National Seashore 

71. Pensacola Bay Service Water 

and Impoundment Monitoring 

(SWIM) Area 

72. Choctawhatchee Bay SWIM Area 

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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-and-water mousse, or tarballs (MMS, 2007b). Oil is generally deposited on beaches in lines 

defined by wave action at the time of landfall. Oil that remains on the beach will thicken as its 

volatile components are lost. Thickened oil may form tarballs or aggregations that incorporate sand, 

shell, and other materials into its mass. Tar may be buried to varying depths under the sand. On 

warm days, both exposed and buried tarballs may liquefy and ooze. Oozing may also serve to expand 

the size of a mass as it incorporates beach materials. Oil on beaches may be cleaned up manually, 

mechanically, or both. Some oil can remain on the beach at varying depths and may persist for 

several years as it slowly biodegrades and volatilizes. 

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 

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) 

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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 3,125 to 3,747 ft (953 to 1,142 

m) of water. No conflict with commercial fishing activity is expected to occur. 

Most recreational fishing activity in the region occurs in water depths less than 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 potentially affecting fisheries is drilling rig presence (including noise and lights). 

Two types of potential accidents are also addressed below – 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 the sea surface with diesel fuel on it 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 recent EISs (MMS, 2007b, 2008; BOEMRE, 

2011; BOEM, 2012b,d). 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. 

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C.8.2 Public Health and Safety 

There are no IPFs associated with routine operations that are expected to affect public health and 

safety. Impacts of a small fuel spill and a large oil spill are addressed below. 

Impacts of a Small Fuel Spill 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations including fuel transfer. In the unlikely event of a spill, implementation of Shell’s OSRP will 

mitigate and reduce the potential for impacts. 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 49 miles (79 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 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 shorebased facilities in 

Louisiana. No new or expanded facilities will be constructed, and no new employees are expected to 

move permanently into the area. The project will have a negligible impact on socioeconomic 

conditions such as local employment, existing offshore and coastal infrastructure (including major 

sources of supplies, services, energy, and water), and minority and lower income groups. Impacts of 

a small fuel spill and a large oil spill are addressed below. 

Impacts of a Small Fuel Spill 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations including fuel transfer. In the unlikely event of a spill, implementation of Shell’s OSRP will 

mitigate and reduce the potential for impacts. EP Section 9b provides detail on spill response 

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measures. Given the open ocean location of the lease area, the duration of a small spill and 

opportunity for impacts to occur would be very brief. 

A small fuel spill that is dissipated within a few days would have little or no economic impact, as the 

spill response would use existing facilities, resources, and personnel. 

Impacts of a Large Oil Spill 

Potential socioeconomic impacts of an oil spill are discussed in recent EISs (MMS, 2007b, 2008; 

BOEM, 2012b,d). 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 49 miles (79 km) from the nearest shoreline. Based on the OSRA modeling 

predictions (Table 3), Plaquemines Parish, Louisiana, is the coastal area most likely to be affected. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an event 

will be minimized by Shell’s well control and blowout prevention measures as detailed in 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. 

C.8.4 Recreation and Tourism 

There are no known recreational uses of the lease area. Recreational resources and tourism in 

coastal areas would not be affected by 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 recent EISs (MMS, 2007b, 

2008; BOEM, 2012b). 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, 

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resulting in negative publicity that encourages people to stay away. Based on OSRA modeling as 

summarized in Table 3, Plaquemines Parish, Louisiana, is the area most likely to be contacted by a 

spill. However, shorelines from Galveston, Texas, to Okaloosa, Florida, could be contacted. These 

areas include popular beaches and recreational sites along the coast. 

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 recent lease sale EISs (MMS, 2007b, 2008; 

BOEM, 2012b,d). 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. 

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. MC 720, 721, and 

722 are 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. 

The archaeological survey conducted by C&C Technologies (2009) detected unidentified sonar targets 

within the survey areas that were classified as modern debris or possibly barrels. Shell’s procedure 

“Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area,” which has been 

previously approved by MMS and BOEM applies to operations that could cause a disturbance of a 

seafloor barrel. Shell’s over‐arching 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. 

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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 multisale EIS in which it analyzed the 

environmental impact of activities that might occur in the multi-lease-sale area. The MMS also 

recently analyzed the cumulative impacts of OCS development activities similar to those planned in 

this 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: Western Planning Area Sales 204, 207, 210, 215, and 218, and Central Planning Area 

Sales 205, 206, 208, 213, 216, and 222 (MMS, 2007b), as updated by a 2012 Final Supplemental EIS 

for Gulf of Mexico OCS Oil and Gas Lease Sales 2012-2017: Western Planning Area Lease Sales 229, 

233, 246, and 248 and Central Planning Area Lease Sales 227, 231, 235, 241 and 247 (BOEM, 2012b). 

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 

additional impacts beyond those evaluated in the Multisale and Final EISs (MMS, 2007b; BOEM, 

2012b). 

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 blocks MC 720, 721, and 

722. Shell does not anticipate other projects in the vicinity of the project area beyond the types of 

projects analyzed in the Multisale and Supplemental EIS (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 

2012b).

Cumulative Impacts of Activities in the EP. The MMS (2007b) multi-lease-sale EIS and BOEM (2012b) 

Final EIS included a lengthy discussion of cumulative impacts, which analyzed the environmental and 

socioeconomic impacts from the incremental impact of the 11 proposed lease sales, in addition to all 

activities (including non-OCS activities) projected to occur from past, proposed, and future lease sales 

during the 40-year period of 2007 to 2046 (see MMS, 2007b; BOEM, 2012b). The EIS considered 

Page 164 Public Information Copy
exploration, delineation, and development wells; platform installation; service-vessel trips; and oil 

spills. The EIS examined the potential cumulative effects on each specific resource for the entire Gulf 

of Mexico. 

The level and type of activity proposed in Shell’s EP are within the range of activities described and 

evaluated in the recent multi-lease-sale EISs. This EIA incorporates and builds on these analyses by 

examining the potential impacts on physical, biological, and socioeconomic resources from the work 

planned in this 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 the 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 national ambient air quality 

standard (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b). In addition, the cumulative 

contribution to visibility impairment is also very small (MMS, 2007b, 2008; BOEMRE, 2011; 

BOEM, 2012b). Since the BOEM completed the multi-lease-sale EISs, the USEPA has adopted a new 

short-term NAAQS for nitrogen dioxide (NO2) and sulfur dioxide (SO2). As mentioned in previous 

sections, projected emissions meet the BOEM exemption criteria and would not contribute to 

cumulative impacts on air quality. 

Climate Change. Carbon dioxide (CO2) and CH4 emissions from the project would constitute a small 

incremental contribution to greenhouse gas emissions from all OCS activities. According to the EIS 

(MMS, 2007a), estimated CO2 emissions from all OCS activities in the 2007-2012 leasing program are 

about 0.08% to 0.016% of the global CO2 emissions from fossil fuel combustion. Greenhouse gas 

emissions may contribute to climate change, with important effects on temperature, rainfall, 

frequency of severe weather, ocean acidification, and sea level rise (Intergovernmental Panel on 

Climate Change, 2007). In the Gulf of Mexico, sea level rise is an important issue due to the ongoing 

losses in coastal wetlands, particularly in coastal Louisiana. Greenhouse gas emissions from the 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 working to reduce greenhouse gas 

emissions by increasing the efficiency of its operations, establishing a substantial capability in CO2

capture and storage, and continuing to research and develop technologies that increase efficiency 

and reduce emissions in hydrocarbon production. In 2010, Shell met a voluntary target set in 1998 

for direct greenhouse gas emissions from its facilities to be at least 5% lower than the comparable 

1990 level (Shell, 2011). Shell’s ongoing efforts to reduce greenhouse gas emissions should offset 

any incremental contribution from the EP. 

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. 

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Archaeological Resources. MC 720, 721, and 722 are on the list of archaeology survey blocks (BOEM, 

2012c). No shipwrecks were detected in the surveys conducted by C&C Technologies, Inc. (2009) and 

GEMS (2010). There are three marine avoidance zones identified in the vicinity of well location F in 

MC 720. 

New Information. New information included in the most recent Supplemental and Final EISs 

(BOEMRE, 2011; BOEM, 2012b) 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. 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-leasesale EISs, the incremental contributions of activities similar to Shell’s proposed activities to the 

cumulative impacts is not significant (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b).

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 MC lease blocks proposed 

for the drilling activities. 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 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 Supplemental and Final EISs 

(BOEMRE, 2011; BOEM, 2012b) has been incorporated into the EIA, where applicable. 

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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; BOEMRE, 2011; BOEM, 2012b). The 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 Supplemental and Final EISs 

(BOEMRE, 2011; BOEM, 2012b) has been incorporated into the EIA, where applicable. 

D. Environmental Hazards 

D.1 Geologic Hazards 

The archaeological and geophysical surveys concluded that the project areas are suitable for the 

proposed activities (C&C Technologies, Inc., 2009; GEMS, 2010). 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 (e.g., 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 

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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. 

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 

The EIA was prepared at the direction of Shell Offshore Inc. by its contractor, CSA International, Inc. 

Contributors included the following: 

73. Tracy Albert (Regulatory Specialist, Regulatory Compliance Consultants of LA, LLC); 

74. Jeffrey McMenis (Environmental Engineer, Shell Exploration & Production Co.); 

75. Michael Mahaffie (Project Leader, Shell Exploration & Production Co.); 

76. James Jorgensen (Drilling Engineer, Shell International Exploration and Production); 

77. Jamie Crider (Geophysicist, Shell Exploration & Production Co.); 

78. John Baird (Reservoir Engineer, Shell Exploration & Production Co.); 

79. June Mire, Ph.D. (Senior Ecologist and Project Manager, Tetra Tech EM, Inc.); 

80. Carlyle Kalloo (Senior Scientist, CSA International, Inc.); 

81. John Thompson (Senior Scientist, CSA International, Inc.); 

82. Neal Phillips, Ph.D. (Senior Scientist, CSA International, Inc.); 

83. Deborah Fawcett (Project Scientist II, CSA International, Inc.); 

84. Stephen Viada (Senior Scientist, CSA International, Inc.); 

85. Keith VanGraafeiland (GIS/Remote Sensing Specialist, CSA International, Inc.); and 

86. Kim Dunleavy (Technical Editor, CSA International, Inc.). 

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SECTION 19: ADMINISTRATIVE INFORMATION

A. Exempted Information Description (Public Information Copies Only) 

The following attachments were excluded from the public information copies of this plan: 

Section 1B OCS Plan Information form – Bottom hole locations & proposed total depth 

Section 2J Blowout Scenario – confidential information for NTL 2010 N06 calculation 

Section 3A Geologic Description 

Section 3B Structure Contour Maps 

Section 3C Interpreted 2D or 3D seismic line(s)

Section 3D Cross Section(s) 

Section 3E Stratigraphic Column with Time vs. depth table 

Section 3G High-Resolution Seismic Lines & Top Hole Progs 

B. Bibliography 

CSA Environmental Impact Analysis, October 2012 

Shallow Hazards Report, prepared by Gems, Inc. (Project No. 0909-1691b) of the shallow drilling hazards 

“Geologic and Stratigraphic Assessment of Blocks 720 (OCS-G 33170), 721 (OCS-G 33171) and 722 (OCS-G 

33172) Mississippi Canyon Area, Gulf of Mexico” dated February 4, 2010. 

C&C Technologies, Archaeological Assessment Report, Blocks 676-678, 720-722, 765-766, and Vicinity, 

Mississippi Canyon Area, Project No. 097403-097494, December, 2009. AUV side-scan sonar and sub-bottom 

profiler data. 

C&C Technologies, Archaeological and Hazard Report, Blocks 808, 809, 852, 853 and Vicinity, Mississippi 

Canyon Area, Project No. 083986-084109, February, 2009. AUV side-scan sonar and sub-bottom profiler data. 

C&C Technologies, Archaeological Assessment Report, Block 854 and Vicinity (Blocks 809-811, 853, 855, 897-

899), Mississippi Canyon Area, Project No. 072879-072915, August 2007. AUV side-scan sonar and sub-bottom 

profiler data. 

Shell’s Regional OSRP (2012)

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