UNITED STATES GOVERNMENT MEMORANDUM

To: Public Information (MS 5030)

Plans Section, Office of Field 

Operations (MS 5231)

Public Information copy of DOCD

Control # - S-07626

Type - Supplemental Development Operations Coordinations Document

Lease(s) - OCS-G07975 Block - 934 Mississippi Canyon Area

OCS-G07976 Block - 935 Mississippi Canyon Area

Operator - Shell Offshore Inc.

Drill and Complete Wells A10 and A11

Not Found

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

should be addressed in an Environmental Assessment.

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

Ulunma Nwokeafor

Plan Coordinator

G07976/MC/935

G07976/MC/935

2819 FNL, 3365 FEL

2809 FNL, 3317 FEL

G07975/MC/934

G07975/MC/934

WELL/A10

WELL/A11

Site Type/Name Botm Lse/Area/Blk Surface Location Surf Lse/Area/Blk

Description -

Rig Type -

Subject:

From:

September 20, 2013
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): A10 Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 7975 

Area Name Mississippi Canyon 

Block No. 934 

Blockline 

Departures 

(in feet)

N/S Departure: 2,819’ FNL 

E/W Departure 3,365’ FEL 

Lambert X-Y 

coordinates 

X: 851,995 

Y: 10,182,301 

Latitude/ 

Longitude

Latitude 28°02’ 14.23” 

Longitude -89°26’40.17” 

TVD (Feet): MD (Feet): Water Depth (Feet): 3,853’ 

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.)

 
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): A11 Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 7975 

Area Name Mississippi Canyon 

Block No. 934 

Blockline 

Departures 

(in feet)

N/S Departure: 2,809’ FNL 

E/W Departure 3,317’ FEL 

Lambert X-Y 

coordinates 

X: 852,043 

Y: 10,182,311 

Latitude/ 

Longitude

Latitude 28°02’ 14.34” 

Longitude -89°26’39.64” 

TVD (Feet): MD (Feet): Water Depth (Feet): 3,853’ 

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.)
COMPANY Shell Offshore Inc. 

AREA Mississippi Canyon BLOCK 934 LEASE OCS-G-7975 PLATFORM MODU WELL A10, A11 COMPANY CONTACT Jeff McMenis TELEPHONE NO. 504-425-6021 REMARKS SEPCO Env File Name - Europa_AQR_DOCD_Condor_111612.xlsx 
B. Projected Ocean Discharges

Solid and Liquid Wastes 

transportation 

Type of Waste Composition Transport Method Name/Location of Facility 

Will drilling occur ? If yes, fill in the muds and cuttings.

EXAMPLE: Oil-based drilling fluid or mud NA NA NA 

Oil-based drilling fluid or mud NA NA NA NA Synthetic-based drilling fluid or mud Used SBF and additives

Drums or dedicated tanks on support vessels MI Drilling Fluids - Fourchon, LA 7,0

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

Drill cuttings from synthetic based interval. Storage tank on supply boat Newpark Environmental, Fourchon, LA 15

Cuttings wetted with oil-based fluids NA NA NA NA 

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

Produced sand NA- this well has sand control NA NA NA EXAMPLE: trash and debris cardboard, aluminum, barged in a storage bin shorebase z 

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

Omega Waste Management, W. Patterson, LA or ARC, New Iberia, LA 22

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

Republic/BFI landfill, Sorrento, LA or the parish landfill, Avondale, LA 11

used oil used oil Drums on supply boat

Omega Waste Management, W. Patterson, LA or ARC, New Iberia, LA 55 

Chemical product wastes Solvent

Captured at surface in MPT tanks, transported onshore for disposal in an environmentally friendly manner.

Safety Kleep, Denton, TX or Lamp Environmental, Hammond, LA 15

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

Waste Dis

TABLE 7B: WASTES YOU WILL TRANSPORT AND /OR DISPOSE OF ONSH

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

Revised DOCD: Europa A10 and Europa 

C. Modeling Report

 Not applicable to this Plan. 

SECTION 6: BIOLOGICAL, PHYSICAL, AND SOCIOECONOMIC INFORMATION

A. Chemosynthetic Communities Report

Reports and Data: Previously submitted 

Shallow Hazards: 

Fugro-McClelland Marine Geosciences, Inc., Shallow Hazards Report, Blocks 891, 934, and 935, Mississippi 

Canyon Area, Gulf of Mexico, Report # 0201-0841, dated November 4, 1990. Data: Deep-Towed Side Scan 

Sonar and Sub-Bottom Profiler data, Sparker data. 

Archaeological: 

C&C Technologies, Shell Exploration and Production Archaeological and Hazard Report, Blocks 890-979, 

Mississippi Canyon Area, U.S. Gulf of Mexico, dated July, 2012, Project #100231. Data: AUV data consisting 

of side scan sonar and sub-bottom profiler. 

Fugro-Geoservices, Archaeological Assessment, Proposed Well Site and Anchor Locations, Blocks 890, 891, 

934, & 935, Mississippi Canyon Area, Gulf of Mexico, Report #2405-1366, dated November 8, 2005. Data: 

Deep-Towed Side Scan Sonar and Sub-Bottom Profiler. 

Proposed Locations and Coordinates: 

Proposed 

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

MC 934 A-10 851995.00 10182301.00 2819.00’ FNL 3365.00’ FEL 3853’ 

MC 934 A-11 852043.00 10182311.00 2809.00’ FNL 3317.00’ FEL 3853’ 

Site Assessment, MC 934, Proposed Location A-10 

Mississippi Canyon 934, Proposed Location A-10 is located in a water depth of approximately 3853 feet. 

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

within 2000 feet of MC 934, Proposed Location A-10. 

The stratigraphy at the site of MC 934, Proposed Location A-10 consists of: 

• Unit 1 (Seafloor – 371‘BML) consists of normal marine drape, hemipelagic mud and muddy mass 

transport deposits (MTD’s). 

 • Unit 2 (371’ – 649’ BML) consists of 278’ of muddy MTD’s 

 • Unit 3 (619’ – 1158’ BML) consists of 509’ of MTD’s with a thin sand package 

• Unit 4 (1158’ – 1591’ BML) consists of 433/ of MTD’s, conformable turbidites with some silty 

sections 

• Unit 5 (1591’ – 1903’ BML) consists of 312’ of muddy channel system that has mostly eroded “Blue 

Unit” 

 • Unit 6 (1903’ – 2497’ BML) consists of 594’ of muddy MTD’s with silty sand at the base 

 • Unit 7 (2497’ – 2726’BML) consists of Muddy MTD’s and conformable turbidites 

 • Unit 8 (2726’ – 3637’ BML) consists of 911’ of regional MTD’s with sands and silts 

• Unit 9 (3637’ – 4475’ BML) consists of 838’ of muddy MTD’s and conformable turbidites with some 

thin sand packages. 

Shallow Water Flow Potential: 

 Low Potential – Seafloor – 649’ BML 

 Moderate Potential – 649’ – 1903’ BML 

 Moderately Low Potential – 1903’ – 2497’ BML 

 Low Potential – 2497’ – 4475’ BML 
SECTION 1: PLAN CONTENTS

A. DESCRIPTION, OBJECTIVES & SCHEDULE

Shell Offshore Inc. (Shell) is submitting this Supplemental DOCD (DOCD/plan) for Mississippi Canyon Blocks 

934 & 935, OCS-G 7975 & 7976. This plan is for the drilling and completion of wells A10 and A11. The 

well(s) will be drilled and completed in accordance with 30 CFR 250.1721. If the wells are unsuccessful, they 

will be permanently plugged and abandoned in accordance with the Bureau of Safety and Environmental 

Enforcement (BSEE) regulations. Undrilled wells A8 and A9 were covered in plan R-5746 and will be drilled in 

2013-2014 with the Atwood Condor. 

The drilling activities are planned to commence on or about February 2014 and last approximately 133 days to 

drill and complete the first well, and January 2015 for the drilling and completion of the second well. The 

timeframe for these 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 61 statute miles from the nearest shoreline, 101 statute miles from the onshore support 

base at Port Fourchon, Louisiana and 88 statute miles from the helicopter base at Boothville, Louisiana. 

Water depths at the well sites range from 3,600’ to 3,900’ (Attachment 1A). 

The proposed rig, The Atwood Condor (Condor) is a 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 this plan. 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 934 

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 plan. 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. WELL LOCATIONS AND JUMPER/FLYING LEADS INSTALLATION

See attached location plat (Attachments 1B) and BOEM forms (Attachments 1C through 1E). 

A dynamically positioned intervention vessel will be used to install the jumper and flying leads. One side of 

the jumper will connect to an existing spare hub on the Europa manifold while the other side will connect to 

the newly installed EA-10 tree. Likewise, the electrical flying leads (EFLs) and Steel Flying Lead (SFL) will 

connect the newly installed tree to existing spare slots on the Europa Subsea Electric Hydraulic Distribution 

Assembly. A Hydraulic Flying Lead (HFL) will connect the newly installed tree directly to the manifold to 

control the manifold branch valves for this new well. Attachment 1F shows the Europa subsea field layout. 

 
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

August 1, 2013 

 

Bureau of Ocean Energy Management 

Office of Field Operations 

1201 Elmwood Park Boulevard 

New Orleans, LA 70123-2394 

 

Attn: Plans Section – GM 1053C 

SUBJECT: Supplemental Development Operations Coordination Document 

 Mississippi Canyon Block 935 Unit No. 754395016 

 Mississippi Canyon Block 934, OCS-G 7975 

 Mississippi Canyon Block 935, OCS-G 7976 

 Offshore Louisiana 

 

Gentlemen: 

In compliance with 30 CFR 550.221 and NTLs 2008-G04 and 2009-G27, giving Development Plan guidelines, 

Shell Offshore Inc. (Shell) requests your approval of this Supplemental Development Operations Coordination 

Document (DOCD) to add two subsea wells, A10 and A11. The Atwood Condor will be the rig used for this 

project, which is expected to begin operations in February 2014. 

The cost recovery fee is attached to the proprietary copy of the plan. 

Should you have any questions or 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
REVISIONS TABLE

Date of Request Plan Section What was Corrected Date Resubmitted

Page 2 Public Information Copy
 

SHELL OFFSHORE INC. 

Supplemental Development Operations Coordination Document 

for 

Mississippi Canyon Block 935 Unit No. 754395016 

Mississippi Canyon Block 934, OCS-G 7975 

Mississippi Canyon Block 935, OCS-G 7976 

PUBLIC INFORMATION COPY 

August 2013

PREPARED BY: 

Tracy W. Albert 

Regulatory Specialist 

504.425.7215 

tracy.albert@shell.com

Page 3 Public Information Copy
DEVELOPMENT OPERATIONS COORDINATION DOCUMENT 

MISSISSIPPI CANYON BLOCK 935 UNIT – NO. 754395016

MISSISSIPPI CANYON BLOCK 934, OCS-G 7975 

MISSISSIPPI CANYON BLOCK 935, OCS-G 7976 

TABLE OF CONTENTS

SECTION 1: PLAN CONTENTS 

SECTION 2: GENERAL INFORMATION 

SECTION 3: GEOLOGICAL AND GEOPHYSICAL 

SECTION 4: HYDROGEN SULFIDE - H2S 

SECTION 5: MINERAL RESOURCE CONSERVATION 

SECTION 6: BIOLOGICAL, PHYSICAL AND SOCIOECONOMIC INFORMATION 

SECTION 7: WASTE AND DISCHARGE INFORMATION 

SECTION 8: AIR EMISSION INFORMATION 

SECTION 9: OIL SPILL INFORMATION 

SECTION 10: ENVIRONMENTAL MONITORING 

SECTION 11: LEASE STIPULATIONS 

SECTION 12: ENVIRONMENTAL MITIGATION MEASURES 

SECTION 13: RELATED FACILITIES AND OPERATIONS INFORMATION 

SECTION 14: SUPPORT VESSELS AND AIRCRAFT 

SECTION 15: ONSHORE SUPPORT FACILITIES INFORMATION 

SECTION 16: SULPHUR OPERATIONS 

SECTION 17: COASTAL ZONE MANAGEMENT ACT INFORMATION 

SECTION 18: ENVIRONMENTAL IMPACT ANALYSIS 

SECTION 19: ADMINISTRATIVE INFORMATION 

Page 4 Public Information Copy
ACRONYMS AND ABBREVIATIONS 

ADIOS 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 

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 

DOCD Development Operations Coordination 

Document 

DPS distinct population segment 

EFH Essential Fish Habitat 

EIA Environmental Impact Analysis 

EIS Environmental Impact Statement 

EFL Electrical flying lead 

ESA Endangered Species Act 

FAD fish-attracting device 

GMFMC Gulf of Mexico Fishery Management 

Council 

H2S hydrogen sulfide 

HAPC Habitat Area of Particular Concern 

HFL Hydraulic flying leads 

IPF impact-producing factor 

MARPOL International Convention for the 

Prevention of Pollution from Ships 

MC Mississippi Canyon 

MMC Marine Mammal Commission 

MMPA Marine Mammal Protection Act 

MMS Minerals Management Service 

MWCC Marine Well Containment Company 

NAAQS National Ambient Air Quality Standards 

NEPA National Environmental Policy Act 

NMFS National Marine Fisheries Service 

NOAA National Oceanic and Atmospheric 

Administration 

NO2 nitrogen dioxide 

NOx nitrogen oxides 

NPDES National Pollutant Discharge Elimination 

System 

NPS National Park Service 

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 

SFL Steel flying leads 

SWSS Sperm Whale Seismic Study 

TLP tension leg platform 

U.S.C. United States Code 

USCG U.S. Coast Guard 

USDOI U.S. Department of the Interior 

USEPA U.S. Environmental Protection Agency 

USFWS U.S. Fish and Wildlife Service 

VOC volatile organic compound 

WCD worst case discharge 

WCEP Whooping Crane Eastern Partnership 

WMA Wildlife Management Area 

Page 5 Public Information Copy
SECTION 1: PLAN CONTENTS

A. DESCRIPTION, OBJECTIVES & SCHEDULE

Shell Offshore Inc. (Shell) is submitting this Supplemental DOCD (DOCD/plan) for Mississippi Canyon Blocks 

934 & 935, OCS-G 7975 & 7976. This plan is for the drilling and completion of wells A10 and A11. The 

well(s) will be drilled and completed in accordance with 30 CFR 250.1721. 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 February 2014 and last approximately 133 days to 

drill and complete the first well, and January 2015 for the drilling and completion of the second well. The 

timeframe for these 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 61 statute miles from the nearest shoreline, 101 statute miles from the onshore support 

base at Port Fourchon, Louisiana and 88 statute miles from the helicopter base at Boothville, Louisiana. 

Water depths at the well sites range from 3,600’ to 3,900’ (Attachment 1A).

The proposed rig, The Atwood Condor (Condor) is a 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 this plan. 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 934 

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 plan. 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. WELL LOCATIONS AND JUMPER/FLYING LEADS INSTALLATION

See attached location plat (Attachments 1B) and BOEM forms (Attachments 1C through 1E). 

A dynamically positioned intervention vessel will be used to install the jumper and flying leads. One side of 

the jumper will connect to an existing spare hub on the Europa manifold while the other side will connect to 

the newly installed EA-10 tree. Likewise, the electrical flying leads (EFLs) and Steel Flying Lead (SFL) will 

connect the newly installed tree to existing spare slots on the Europa Subsea Electric Hydraulic Distribution 

Assembly. A Hydraulic Flying Lead (HFL) will connect the newly installed tree directly to the manifold to 

control the manifold branch valves for this new well. Attachment 1F shows the Europa subsea field layout. 

Page 6 Public Information Copy
C. RIG SAFETY AND POLLUTION FEATURES 

The rig (Atwood Condor or similar) will comply with all of the regulations of the American Bureau of Shipping 

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

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

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

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

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

prevention measures are contaminated and non-contaminated drain system, mud drain system and oily water 

processing. The Atwood Condor has a SOPEP plan and for actual spills, six (6) SOPEP kits are on deck in key 

areas. Additionally, the Condor has Operating Procedures and Job Safety Analysis for any fuel, base oil or 

SBM transfers. 

DRAIN SYSTEM POLLUTION FEATURES 

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

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

removable strainer plate to prevent debris entering the system. 

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

pans and work areas, are discharged depending on if it came into contact with the contaminated or noncontaminated areas of the Rig. 

1) Non-contaminated Drains 

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

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

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

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

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

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

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

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

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

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

drain. 

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

deployment as appropriate) and reported immediately. 

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

are in place as needed to ensure a proper seal. 

2) Contaminated Drains 

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

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

processing. 

3) Oily Water Processing 

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

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

the MODU, an oil record log will be kept according to instructions included in the log. Any and all pollution 

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

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

and sent to shore for disposal. All waste oil that is sent in to be disposed of is recorded in the MODU’s oil log 

book. 

Page 7 Public Information Copy
All discharges will be in accordance with applicable EPA NPDES permits. See Section 18 of this Plan. 

4) Lower Hull Bilge System 

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

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

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

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

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

for high and low levels. 

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

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

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

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

• Portable submersible pumps 

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

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

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

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

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

5) Emergency Bilge System 

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

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

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

6) Oily Water Drain/Separation System

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

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

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

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

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

and are subjected to sheen tests before discharge as well. 

7) Drain, Effluent and Waste Systems 

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

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

or non-hazardous drains from nonhazardous areas. 

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

areas, the drainage systems are segregated. 

• The rig’s drainage system ties into oily water separators that take out elements in the drainage that 

could harm the environment. This is part of rig contractor’s initiative to be good stewards of the 

environment. The oily water separators divide the drainage system into these sections below. 

8) Rig Floor Drainage 

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

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

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

separators and cleaned further to reduce oil content to <15 ppm.

Page 8 Public Information Copy
9) Columns #3 & 4 

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

columns. The separators in these columns go through three cycles of circulation and remove oil to <15 ppm, 

then discharge the clean product to sea. 

10) Main Engine Rooms 

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

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

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

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

• Column #3 – Westfalia WSD-18

• Column #4 – Westfalia WSD-18

• Drill Floor – Facet International MAS 34-3 

11) Helideck Drains 

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

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

helideck structure. 

Operating configurations are as follows: 

 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. The 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 and 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 to the Port column oily water separator which 

discharges water overboard from the water side and oil is pumped out into a 550 gallon tote tank on 

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

D. Storage Tanks - Atwood Condor (or similar) 

Tank Name Tank Number of Total Contents

Capacity (bbls) Tanks Capacity (bbls) Gravity (API)

Fuel Oil Storage 4,418 4 17,672 33°

Fuel Oil Storage 3,787 1 3,787 33°

Fuel Oil Storage 234 6 1,404 33°

Lube Oil 28 4 112 22.3°

Lube Oil 41 2 82 22.3°

Waste Oil 325 1 325 6.5°

Waste Oil 49 1 49 6.5°

Page 9 Public Information Copy
E. Pollution Prevention Measures 

Pursuant to NTL 2008-G04 the proposed operations covered by this plan 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

 

 Health, safety, and environment (HSE) are the primary topics in pre-tour and pre-job safety 

meetings. The discussion around no harm to people or environment is a key mindset. All personnel 

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

 All tools that come to and from the rig have their pollution pans inspected and cleaned, and plug 

installation confirmed prior to leaving the dock and prior to loading on the boat. 

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

on a routine scheduled basis. 

 All pollution pans on rig are inspected daily. 

 Containment dikes are installed around all oil containment, drum storage areas, fuel vents, and fuel 

storage tanks. 

 All used oil and fuel is collected and sent to shore for recycling. 

 Direct overboard drains on the rig are checked regularly to verify drain plugs are installed. 

 All trash containers are checked and emptied daily, and trash containers are kept covered. Trash is 

collected in a compactor and shipped to shore for disposal. 

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

 Fuel hoses are changed on an annual basis. 

 Spill prevention fittings are installed on all liquid take-on hoses. 

 Shell has obtained International Organization for Standardization (ISO) 14001 certification. 

 Shell will use low-sulfur fuel to reduce air pollutant impacts. 

G. Description of Previously Approved Lease Activities

Wells A1, A2 and A4 were previously drilled to MC 934. Well A5, A6 and A7 were previously drilled in MC 

935. 

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: Exploration Plan (EP) X 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 7975 & 7976 Area: MC Block(s): 934 & 935 Project Name (If Applicable): Europa

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

Boothville

Distance to Closest Land (Miles): 61

Description of Proposed Activities (Mark all that apply)

Exploration drilling X Development drilling

X 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

X Installation of subsea wellheads and/or manifolds X 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? X Yes No

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

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

Do you propose any activities that may disturb a BOEM-designated high-probability archaeological area? 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 well A10 2/1/2014 5/12/2014 100

Complete well A10 5/12/2014 6/14/2014 33

Installation of jumper, fly leads 7/1/2014 7/8/2014 7

Commence production Well A10 8/1/2014

Drill well A11 1/1/2015 4/11/2015 100

Complete well A11 4/11/2015 5/14/2015 33

Installation of jumper, fly leads 6/1/2015 6/8/2015 7

Commence production Well A11 7/1/2015

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): Atwood Condor or similar Spar Other (Attach Description)

Description of Lease Term Pipelines

From (Facility/Area/Block) To (Facility/Area/Block) Diameter (Inches) Length (Feet)

Europa Hub MC 934 Well A10 MC 934 5” ID 80’

Europa Hub MC 934 Well A11 MC 934 5” ID 73’

Page 12 Public Information Copy
Form BOEM-0137 (December 2011-Supercedes all previous editions of form BOEM-0137 which may not be used.) 

 

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): A10 Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 7975

Area Name Mississippi Canyon

Block No. 934

Blockline

Departures

(in feet)

N/S Departure: 2,819’ FNL

E/W Departure 3,365’ FEL

Lambert X-Y 

coordinates

X: 851,995

Y: 10,182,301

Latitude/

Longitude

Latitude 28°02’ 14.23”

Longitude -89°26’40.17”

TVD (Feet): MD (Feet): Water Depth (Feet): 3,875’

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): A11 Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 7975

Area Name Mississippi Canyon

Block No. 934

Blockline

Departures

(in feet)

N/S Departure: 2,809’ FNL

E/W Departure 3,317’ FEL

Lambert X-Y 

coordinates

X: 852,043

Y: 10,182,311

Latitude/

Longitude

Latitude 28°02’ 14.34”

Longitude -89°26’39.64”

TVD (Feet): MD (Feet): Water Depth (Feet): 3,875’

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 - Europa Subsea Field Layout 

Page 15 Public Information Copy
SECTION 2: GENERAL INFORMATION

A. Application and Permits

Application/Permit Issuing Agency Status

Rig Movement Report USCG, MWA & NGA Pending

B. Drilling Fluids 

See Section 7, Tables 7A and 7B for this information. 

C. Production

Type Average Production Rate

Peak Production 

Rate

Life of 

Reservoir

D. Oil Characteristics 

H Condensate Characteristic Analytical Methodologies

Should Be Compatible With:

1. Gravity (API) 41.84 ASTM D4052

2. Flash Point (oC) < ASTM D93/IP 34

3. Pour Point (oC) <-26 oC ASTM D97

4. Viscosity (Centipoise at 25 oC) ASTM D445

5. Wax Content (wt %) 

Precipitate with 2-

butanon/dichloromethane

(1 to 1 volume) at -10 oC

6. Asphaltene Content (wt %) 0.02 IP-Method 143/84

7. Resin Content (wt %) 2.52 Jokuty et al., 1996

8. Boiling point distribution including, for 

each

fraction, the percent volume or weight 

and the

boiling point range in oC

ASTM D2892 (TBP distillation) or

ASTM D2887/5307

9. Sulphur (wt %) 0.99 ASTM D4294

Note: If the distillation information in Item No. 8 in the above table is not available, the GOMR may accept 

the asphaltenes, and resins; and total BTEX (ppm) using analytical methods compatible with the 

Hydrocarbon Groups methodology found in Jokuty et al., 1996). 

All in wt% Topped Basis 

SARA (Topped Basis) All in wt %

Well # Saturates Aromatics Resin Asphaltenes

A5 H sand (API # 6081741068) 62.2 31.8 6.0 0.05

Page 16 Public Information Copy
Identify the oil you analyze. Refer to the following sample chart. 

Oil from one well Oil from more than one 

well sampled on a facility Oil from a pipeline system

·Area/Block 

·MMS platform 

·API Well No. 

·Completion perforation

 interval 

·BOEM’s reservoir name

·Sample date 

·Sample No.(if more than one 

is taken) 

·Area/Block

·BSEE platform ID 

·Field/Unit 

·Sample date 

·Sample No. (if more than one 

is taken)

·Listing of API Well Nos.

·Storage tank ID No. (if 

sampled at a storage tank)

·Pipeline segment number

·For each pipeline that feeds 

into the system, the ID codes 

for the closest upstream LACT 

units and/or facility 

measurement points

·Storage tank ID No. (if 

sampled at a storage tank)

Sample Detail

Area/Block MC934

BSEE Platform OCS-G 7975

API Well No. A5

Completion Perforation 18,252' MD

BOEM Reservoir Name H Sand

Sample Date 6-Sep-2005

2B Oil Characteristics I Sand

If DOCD is offshore Florida, a new surface facility in water deeper than 400 meters (1,312’), or one in any 

water depth that supports subsea development in water depths greater than 400 meters (1,312’) complete 

the following two tables: 

Provide the estimated chemical and physical characteristics of the oils that will be handled, stored, or 

transported on/by the facility. 

L Oil Characteristic Analytical Methodologies

Should Be Compatible With:

1. Gravity (API) 28.8 ASTM D4052

2. Flash Point (oC < ASTM D93/IP 34

3. Pour Point (oC) -26 oC ASTM D97

4. Viscosity (Centipoise at 25 oC) ASTM D445

5. Wax Content (wt %) 

Precipitate with 2-

butanon/dichloromethane

(1 to 1 volume) at -10 oC

6. Asphaltene Content (wt %) 3.97 IP-Method 143/84

7. Resin Content (wt %) 6.19 Jokuty et al., 1996

8. Boiling point distribution including, for 

each

fraction, the percent volume or weight 

and the

boiling point range in oC

ASTM D2892 (TBP distillation) or

ASTM D2887/5307

9. Sulphur (wt %) 3.29 ASTM D4294

Note: If the distillation information in Item No. 8 in the above table is not available, the GOMR may accept 

the following information in lieu of Items Nos. 5, 6, 7, and 8: weight percent total of saturates, aromatics, 

waxes, asphaltenes, and resins; and total BTEX (ppm) using analytical methods compatible with the 

Hydrocarbon Groups methodology found in Jokuty et al., 1996). 

Page 17 Public Information Copy
All in wt% Topped Basis 

SARA (Topped Basis) All in wt %

Well # Saturates Aromatics Resin Asphaltenes

A1 I sand (API #6081740835) 20.09 58.35 14.1 10.7

Identify the oil you analyze. Refer to the following sample chart. 

Oil from one well Oil from more than one 

well sampled on a facility Oil from a pipeline system

·Area/Block 

·BSEE platform 

·API Well No. 

·Completion perforation

 interval 

·BSEE’s reservoir name

·Sample date 

·Sample No.(if more than one 

is taken) 

·Area/Block

·BSEE platform ID 

·Field/Unit 

·Sample date 

·Sample No. (if more than one 

is taken)

·Listing of API Well Nos.

·Storage tank ID No. (if 

sampled at a storage tank)

·Pipeline segment number

·For each pipeline that feeds 

into the system, the ID codes 

for the closest upstream LACT 

units and/or facility 

measurement points

·Storage tank ID No. (if 

sampled at a storage tank)

Sample Detail 

Area/Block MC934

BSEE Platform OCS-G-7975

API Well No. A1

Completion Perforation 16,353' MD

BSEE Reservoir Name I Sand

Sample Date 5-Mar-2000

E. New Or Unusual Technology

There is no new or unusual technology associated with this Plan. 

 

F. Bonding

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

furnished and maintained according to 30 CFR Part 256, subpart I; NTL No. 2000-G16, Guideline for 

General Lease Surety Bonds;” and additional security under 30 CFR 256.53(d) and National NTL No. 

2008-N07, “Supplemental Bond Procures.”

G. Oil Spill Financial Responsibility (OSFR)

Shell Offshore Inc. (Shell), BOEM Operator Number 0689, has demonstrated oil spill financial 

responsibility for the facilities proposed in the DOCD according to 30 CFR part 253, and NTL No. 2008-

N05, “Guidelines for Oil Spill Financial Responsibility for Covered Facilities.”

H. Deepwater well control statement

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

and conduct other emergency well control operations. 

I. Suspension of Production

Lease is held by unit production from the Mississippi Canyon Block 935 Unit No. 754395016. 

Page 18 Public Information Copy
J. Blowout scenario

This section was provided and accepted by BOEM in Plan S-7405. The wells proposed in this plan are 

part of the Mississippi Canyon Block 935 Unit No. 754395016 and are targeting the same reservoirs that 

were previously submitted and approved by BOEM. The WCD for wells A10 and back-up well A11

calculate to 185,204 BOPD, which does not exceed the WCD that was submitted and approved for Well 

A7 in Plan S-7405 of 207,677 BOPD. 

This Section 2j was prepared by Shell Offshore Inc. (Shell) pursuant to the guidance provided in the 

Bureau of Ocean Energy Management (BOEM) Notice to Lessees (NTL) No. 2010-N06 with respect to 

blowout and worst case discharge scenario descriptions. 

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

intervention, containment and recovery. 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 with the goal of safe and environmentally sound well 

construction. Shell continues to invest independently in Research and Development (R&D) to improve 

safety and reliability of our well systems. Shell intends to comply with all applicable laws, regulations, 

rules and Notice to Lessees. 

Shell is a founding member of the Marine Well Containment Company (MWCC) and will have access to 

an integrated subsea well control and containment system that can be rapidly deployed through the 

MWCC. MWCC is a non-profit organization that owns, manages, and provides fully trained crews and 

operates the subsea containment system during a response. The near term containment response 

capability will include lessons learned and equipment used in the Macondo response. Shell is investing 

in R&D to improve containment systems. Also, Shell is a member of Clean Caribbean America (CCA), 

Marine Spill Response Corporation (MSRC), Clean Gulf Associates (CGA), and OSRL/EARL to provide the 

resources necessary to respond to a spill as outlined in our Regional Oil Spill Response Plan (OSRP). 

The Worst Case Discharge (WCD) blowout scenario for Europa is calculated for the MC-935 A7 holesection with all potentially producible hydrocarbons sands, commingled based on the guidelines 

outlined in NTL No. 2010-N06 along with subsequent Frequently Asked Questions (FAQ). The WCD 

does not take into account potential flow mitigating factors such as well bridging, obstructions in 

wellbore, reservoir barriers, or early intervention. 

Uncontrolled blowout (volume first day) 207,677 bbl 

Uncontrolled blowout rate (first 30-days average daily rate) 134,011 bopd 

Duration of flow (days) based on relief well 96 days 

Total volume of spill (bbls) for 96 days 6.3 MMBO 

Table 1 Worst Case Discharge Summary 

The Europa field is a subsea development in the deepwater Gulf of Mexico tied back to the Mars TLP 

via two 8” flow lines with a total capacity of 60,000 BOPD. It is located on a three-block BOEM unit 18 

miles southwest of the Mars platform. The subsea system is located in 3,875 feet of water. 

The Europa field production began in early 2000 as a three-well development. The Phase 1 

development focused on the upper sands. The phase 2 development added wells to the sands. 

Currently there are five Europa producers. 

1) Purpose 

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

blowout scenario description, further information regarding any potential oil spill, the assumptions and 

calculations used to determine the WCD and the measures taken to firstly enhance the ability to 

prevent a blowout and secondly to 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 

Europa development wells and seismic. These parameters are better than or consistent with the 

Page 19 Public Information Copy
estimates used by Shell to justify the investment. Therefore, these assumed parameters were used to 

calculate the WCD. They do not reflect probabilistic estimates. 

2) Background 

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

Exploration Plans as requested by NTL No. 2010-N06 in response to the explosion and sinking of the 

Mobile Offshore Drilling Unit (MODU) Deepwater Horizon and the resulting subsea well blowout and 

recovery operations of the exploration well at the MC-252 Macondo location. 

3) Information Requirements 

a) Blowout scenario 

Each hole-section was considered as a possible candidate for the worst case discharge scenario. The 

simulated blowout modeled 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) The greatest discharge potential identified is the hole-section with all potentially producible 

hydrocarbons sands commingled. The worst case discharge rate is 207,677 bopd (average of the first 

24 hours). 

c) Total volume and maximum duration of the potential blowout 

Duration of flow (days) 96 days total duration to drill relief well 

(18 rig mob, 50 spud to base of 

sand, 28 ranging). 

Total volume of spill (bbls) 6.3 MMBO based on 96 days flowing. 

Note: From MBAL model 

Table 2 Estimated Duration and Volume of a Potential Blowout 

Category DOCD 

Type of Activity Drilling 

Facility Location (area/block) MC-935 

Facility Designation MODU 

Distance to Nearest Shoreline (miles) 61 Statute miles 

Uncontrolled blowout (volume first day) 207,700 bbl 

Uncontrolled blowout rate 

(first 30-days average daily rate) 134,011 bopd 

Table 3 Estimated Flow Rates 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. At very short times, e.g. during the first 24 

hours, the pressure profile in the reservoir changes from the moment when a well first starts flowing to 

a pseudo-steady state pressure profile with time, and as a result the rate declines. At somewhat longer 

time scales, effects such as reservoir voidage and the impact of boundaries can cause the rate to drop 

continuously with production. Simulation and material balance models can include these effects and 

form the basis of the NTL No. 2010-N06 calculations for 24-hour and 30-day rates as well as maximum 

duration volumes. 

d) Assumptions and calculations. This data was provided and approved in Plan S-7405. 

Page 20 Public Information Copy
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 sand face. Given the substantial fluid 

velocities inherent in the WCD, and the scenario as defined where the formation is not supported by a 

cased and cemented wellbore, it is possible that the borehole may fail/collapse/bridge over within the 

span of a few days, significantly reducing the outflow rates. However, this WCD scenario does not 

include any bridging. 

f) Likelihood for intervention to stop the blowout. 

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

key focus of our operations. This is derived from robust standards, well design, prudent operations, 

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 Drilling Safety Rule with 

respect to Remotely Operated Vehicle (ROV) hot stab capabilities, a deadman system, and an 

autoshear system. The rig also has 2 shearing rams in the BOP for added redundancy. Also, the rig is 

equipped with a deadman system and an autoshear 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. 

Should the interventions at the well not be possible, specialized equipment can be used to connect to a 

riser stub, damaged connector, casing stub or to the sea floor and allow the well to be shut-in to 

contain the blowout. The subsea containment assembly and other specialized connection devices will 

be available from the Marine Well Containment Company (MWCC). If full shut-in, following capping is 

not possible because of well integrity issues, the well can be flowed with back-pressure maintained via 

the MWCC specialized well flow equipment. 

Shell is investing in Research and Development activities on its own to identify additional containment 

components and equipment that will potentially increase the range of applications and effectiveness for 

equipment similar to that of MWCC, and systems that can be deployed more effectively in the water 

column that resemble “tents or capture domes”, and enhance well shut-in capability. 

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

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

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

by a total of four to six MODU rigs in 2014 – 2017 timeframe. The dynamically positioned rigs under 

contract, the Noble Danny Adkins and the Bully 1, will be the preferred rigs for blowout intervention 

work. However, moored rigs can also be used in some scenarios. Additionally, in the event of a 

blowout, there is the distinct possibility that other non-contracted rigs in the GOM could be utilized 

whether for increased expediency or better suitability. All efforts will be made at the time to secure the 

appropriate rig. Shell’s current contracted rigs capable of operating at Europa water depths and 

reservoir depths are in the following table: 

Page 21 Public Information Copy
 Rig Name Rig Type 

Deepwater Nautilus moored semi-submersible 

Noble Jim Thompson moored semi-submersible 

Noble Danny Adkins dynamically positioned semi-submersible 

Bully 1 dynamically positioned drill ship 

Noble Globetrotter I dynamically positioned drill ship 

Table 4 Shell Contracted Rigs Capable at Europa. 

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. The list of rigs capable of operating at Europa is tabled above. It is expected to take an average 

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

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

relief well will take approximately 50 days to drill down to the last casing string above the blowout 

zone, plus approximately 28 days for precision ranging activity to intersect the blowout well bore. Total 

time to drill a relief well would be 96 days for the Europa well. 

 

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

prepare mooring on the relief well site while the rig is being mobilized. This mooring activity is not 

expected to delay initiation of relief well drilling operations. Shell has 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 distances of over fifteen miles to 

the discovery. 

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). The safety case requirement is ingrained 

into Shell’s Health, Security, Safety, Environment, and Social Performance Control Framework. 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 

Page 22 Public Information Copy
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 Europa. 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 drilling foreman and Shell representative to report any observed 

anomalies so appropriate action can be taken. 

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

support traditional rig-site monitoring since 2003. Well site operations are lived virtually by onshore 

teams consisting of geoscientists, petrophysicists, well engineers, and 24/7 monitoring specialists. The 

same real time well control indicators monitored by the rig personnel are watched by the monitoring 

specialist for an added layer of redundancy. 

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

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

control, such as by International Association of Drilling Contractors (IADC) and International Well 

Control Forum (IWCF) are also mandated. Progressions have elements of competency and Shell 

continues to have comprehensive internal training programs. The best systems and processes can be 

defeated by lack of knowledge and/or improper values. We believe that a combination of HSE tools 

(e.g. stop work, pre-job analysis, behavior based safety, DWOPs, audits), management HSE 

involvement and enforcement (e.g. compliance to life saving rules) have created a strong safety culture 

in our operations. 

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

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

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

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

situation. Resources are dedicated to these systems and drills are run frequently to test preparedness 

(security, medical, oil spill, and hurricane). This same framework is activated and tested during 

hurricane evacuations, thereby maintaining a fresh and responsive team. 

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

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

establishing protocols to mobilize specialists and pre-selecting sources, and developing mobilization 

plans for personnel, material and services for well control procedures. The plan references individual 

activity checklists, a roster of equipment and services, initial information gathering forms, a generic 

description of relief well drilling, strategy and guidelines, intervention techniques and equipment, site 

safety management, exclusion zones, and re-boarding. 

Page 23 Public Information Copy
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 and is a founding 

member of MWCC. 

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 OSRP 

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 an 

exploration well blowout. Shell’s program is developed to fully satisfy federal oil spill planning 

regulations. The Regional OSRP presents specific information on the response program that includes a 

description of personnel and equipment mobilization, the incident management team organization, and 

the strategies and tactics used to implement effective and sustained spill containment and recovery 

operations. 

 

Page 24 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. Shallow Hazards Report

Shallow Hazards Report, Blocks 891, 934, and 935, Mississippi Canyon Area, Gulf of Mexico, 

prepared by Fugro McClelland, report #0201-0841, November 4, 1990. Deep-Towed Side Scan 

Sonar and Sub-Bottom Profiler data, Sparker data was previously submitted. 

Shell Exploration and Production Archaeological and Hazard Report, Blocks 890-979, Mississippi 

Canyon Area, U.S. Gulf of Mexico, prepared by C&C Technologies, July, 2012, Project 100231. AUV 

data consisting of side scan sonar and sub-bottom profiler was previously submitted. 

Archaeological Assessment, Proposed Well Site and Anchor Locations, Blocks 890, 891, 934, & 935, 

Mississippi Canyon Area, Gulf of Mexico, Fugro Geoservices, report 2405-1366, November 8, 2005. 

Deep-Towed Side Scan Sonar and Sub-Bottom Profiler was previously submitted. 

F. Shallow Hazards Assessment

See Section 6 for full shallow hazards and chemo assessment. 

G. High-resolution seismic lines

Proprietary Data 

H. Stratigraphic Column and Time versus Depth Table:

Proprietary Data 

Page 25 Public Information Copy
SECTION 4: HYDROGEN SULFIDE (H2S) 

A. Concentration 

0 ppm. 

B. Classification

Based on 30 CFR 550.215, Shell requests that the Regional Supervisor, Field Operations, determine 

the zones in the proposed drilling operations in this plan are classified as an area where the absence 

of H2S has been confirmed. 

C. H2S Contingency Plan

According to NTL 2008-G04 this is not applicable to this plan. 

D. Modeling Report

We do not anticipate to encounter or handle H2S at concentrations greater than 500 parts per million 

(ppm) and therefore have not included modeling for H2S.

Page 26 Public Information Copy
SECTION 5: MINERAL RESOURCE CONSERVATION INFORMATION

A. Technology and reservoir engineering practices and procedures

Proprietary Data 

B. Technology and recovery practices and procedures

Proprietary Data 

 

 

C. Reservoir Development 

Proprietary Data 

Page 27 Public Information Copy
SECTION 6: BIOLOGICAL, PHYSICAL, AND SOCIOECONOMIC INFORMATION

A. Chemosynthetic Communities Report

Reports and Data: Previously submitted to BOEM. 

Shallow Hazards: 

Fugro-McClelland Marine Geosciences, Inc., Shallow Hazards Report, Blocks 891, 934, and 935, Mississippi 

Canyon Area, Gulf of Mexico, Report # 0201-0841, dated November 4, 1990. Data: Deep-Towed Side Scan 

Sonar and Sub-Bottom Profiler data, Sparker data. 

Archaeological: 

C&C Technologies, Shell Exploration and Production Archaeological and Hazard Report, Blocks 890-979, 

Mississippi Canyon Area, U.S. Gulf of Mexico, dated July, 2012, Project #100231. Data: AUV data consisting 

of side scan sonar and sub-bottom profiler. 

Fugro-Geoservices, Archaeological Assessment, Proposed Well Site and Anchor Locations, Blocks 890, 891, 

934, & 935, Mississippi Canyon Area, Gulf of Mexico, Report #2405-1366, dated November 8, 2005. Data: 

Deep-Towed Side Scan Sonar and Sub-Bottom Profiler. 

Proposed Locations and Coordinates: 

Proposed 

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

MC 934 A-10 852043.00 10182311.00 2809.00’ FNL 3317.00’ FEL 3853’

MC 934 A-11 851995.00 10182301.00 2819.00’ FNL 3365.00’ FEL 3853’

Site Assessment, MC 934, Proposed Location A-10

Mississippi Canyon 934, Proposed Location A-10 is located in a water depth of approximately 3853 feet. 

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

within 2000 feet of MC 934, Proposed Location A-10. 

The stratigraphy at the site of MC 934, Proposed Location A-10 consists of: 

• Unit 1 (Seafloor – 371‘BML) consists of normal marine drape, hemipelagic mud and muddy mass 

transport deposits (MTD’s).

• Unit 2 (371’ – 649’ BML) consists of 278’ of muddy MTD’s

• Unit 3 (619’ – 1158’ BML) consists of 509’ of MTD’s with a thin sand package 

• Unit 4 (1158’ – 1591’ BML) consists of 433/ of MTD’s, conformable turbidites with some silty 

sections 

• Unit 5 (1591’ – 1903’ BML) consists of 312’ of muddy channel system that has mostly eroded “Blue 

Unit”

• Unit 6 (1903’ – 2497’ BML) consists of 594’ of muddy MTD’s with silty sand at the base

• Unit 7 (2497’ – 2726’BML) consists of Muddy MTD’s and conformable turbidites

• Unit 8 (2726’ – 3637’ BML) consists of 911’ of regional MTD’s with sands and silts

• Unit 9 (3637’ – 4475’ BML) consists of 838’ of muddy MTD’s and conformable turbidites with some 

thin sand packages. 

Shallow Water Flow Potential: 

 Low Potential – Seafloor – 649’ BML

 Moderate Potential – 649’ – 1903’ BML

 Moderately Low Potential – 1903’ – 2497’ BML

 Low Potential – 2497’ – 4475’ BML

Page 28 Public Information Copy
Shallow Gas Potential: 

 Low Potential – Seafloor – 4475’ BML

Chemo/Anchor Assessment, MC 934, Proposed Location A-10 (No Anchors – DP Vessel) 

Mississippi Canyon 934, Proposed Location A-10 is located in a water depth of approximately 3853 feet. 

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

within 2000’ of MC 934, Proposed Location A-10. MC 934, Proposed Location A-10 will not disturb any highdensity areas of benthic communities. 

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

934, Proposed Location A-10: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc A-10

Direction from 

Prop Loc A-10

999 100’ 851619.02 10182629.61 499.35 Southeast

1111 100’ 852834.07 10182390.00 843.78 Southwest

935 100’ 851201.66 10182595.67 846.30 Southeast

1133 100’ 853112.40 10182743.67 1201.89 Southwest

1141 100’ 853240.60 10183144.34 1504.24 Southwest

The following table consisting of 29 targets, is a listing of barrels identified within 2000’ of MC 934, Proposed 

Location A-10: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc A-10

Direction from 

Prop Loc A-10

1001 50’ 851696.28 10182069.09 422.77 Northeast

981 50’ 851516.56 10182325.08 526.63 Southeast

972 50’ 851463.70 10182240.74 583.55 Northeast

973 50’ 851465.40 10182421.19 588.02 Southeast

980 50’ 851506.46 10182573.12 597.14 Southeast

969 50’ 851441.45 10182671.66 701.38 Southeast

1101 50’ 852755.67 10182564.28 756.34 Southwest

1115 50’ 852899.54 10182212.13 862.23 Northwest

1117 50’ 852929.23 10182409.19 891.65 Southwest

938 50’ 851222.80 10182762.64 936.33 Southeast

951 50’ 851292.38 10182882.96 943.70 Southeast

937 50’ 851221.82 10182901.20 1011.27 Southeast

1007 50’ 851737.19 10183287.59 1023.35 Southeast

1096 50’ 852649.11 10181257.73 1215.21 Northwest

1136 50’ 853130.85 10182852.83 1215.32 Southwest

877 50’ 850696.13 10182321.85 1346.91 Southeast

1145 50’ 853282.34 10183088.31 1462.93 Southwest

856 50’ 850491.55 10182377.29 1552.87 Southeast

1163 50’ 853695.48 10182275.07 1652.87 Northwest

849 50’ 850405.10 10181839.82 1704.33 Northeast

845 50’ 850373.58 10181875.65 1725.25 Northeast

1023 50’ 851846.31 10180571.81 1750.28 Northeast

960 50’ 851391.16 10183940.64 1755.17 Southeast

1008 50’ 851737.61 10180572.66 1764.96 Northeast

932 50’ 851120.16 10180748.44 1814.73 Northeast

1178 50’ 853865.72 10182464.77 1829.19 Southwest

1181 50’ 853925.37 10182472.00 1889.24 Southwest

908 50’ 850890.65 10183836.73 1912.00 Southeast

860 50’ 850536.23 10181062.48 1956.82 Northeast

Page 29 Public Information Copy
The following table consisting of 2 targets is a listing of marine avoidance zones identified within the 1000’ 

buffer zone (2000’ – 3000’) for MC 934, Proposed Location A-10. 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc A-10

Direction from 

Prop Loc A-10

1124 100’ 852977.59 10184541.35 2446.35 Southwest

765 100’ 849566.97 10183027.12 2534.28 Southeast

The following table consisting of 45 targets is a listing of barrels identified within the 1000’ buffer zone (2000’ 

– 3000’) for MC 934, Proposed Location A-10.

Avoidance 

Zone Number Avoidance Size

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc A-10

Direction from 

Prop Loc A-10

966 50’ 851420.30 10180345.79 2061.51 Northeast

963 50’ 851414.15 10180342.93 2066.10 Northeast

1079 50’ 852421.02 10184355.33 2078.99 Southwest

882 50’ 850739.17 10183968.55 2108.90 Southeast

815 50’ 850113.56 10181295.52 2180.35 Northeast

965 50’ 851415.58 10180149.92 2250.32 Northeast

964 50’ 851415.16 10180140.45 2259.53 Northeast

784 50’ 849805.72 10182659.94 2264.33 Southeast

1168 50’ 853729.69 10183859.84 2289.94 Southwest

843 50’ 850366.45 10180704.71 2321.85 Northeast

778 50’ 849707.04 10182559.18 2349.11 Southeast

777 50’ 849683.08 10182221.43 2361.62 Northeast

1175 50’ 853841.43 10183889.72 2393.05 Southwest

888 50’ 850751.31 10184400.19 2456.25 Southeast

1169 50’ 853774.27 10184059.85 2460.85 Southwest

767 50’ 849580.66 10182286.12 2462.47 Northeast

762 50’ 849560.35 10182215.55 2484.48 Northeast

1207 50’ 854317.81 10183364.46 2506.90 Southwest

998 50’ 851613.43 10184826.55 2551.96 Southeast

759 50’ 849537.82 10183012.94 2601.66 Southeast

1180 50’ 853916.16 10184132.33 2612.66 Southwest

748 50’ 849436.38 10182115.87 2613.91 Northeast

745 50’ 849421.05 10182412.77 2623.92 Southeast

1228 50’ 854680.44 10182377.83 2638.29 Southwest

752 50’ 849476.05 10182978.63 2652.35 Southeast

772 50’ 849613.20 10183408.72 2666.26 Southeast

979 50’ 851506.17 10179689.89 2675.52 Northeast

1233 50’ 854737.68 10182406.86 2696.38 Southwest

741 50’ 849355.29 10182671.06 2711.72 Southeast

747 50’ 849431.57 10183060.77 2716.93 Southeast

1187 50’ 853996.47 10184230.93 2739.01 Southwest

809 50’ 850067.26 10184224.24 2750.28 Southeast

1192 50’ 854052.80 10184241.79 2786.98 Southwest

732 50’ 849288.78 10181857.37 2791.33 Northeast

1243 50’ 854845.64 10182370.78 2803.28 Southwest

875 50’ 850657.41 10184750.78 2805.78 Southeast

796 50’ 849908.87 10184160.86 2824.27 Southeast

740 50’ 849350.29 10183198.19 2835.10 Southeast

1026 50’ 851872.88 10179469.91 2846.18 Northeast

816 50’ 850116.06 10184431.34 2865.12 Southeast

Page 30 Public Information Copy
726 50’ 849237.89 10181623.74 2888.07 Northeast

1194 50’ 854066.33 10184446.18 2941.57 Southwest

1239 50’ 854791.72 10183370.69 2945.91 Southwest

1030 50’ 851891.72 10179366.34 2948.54 Northeast

1201 50’ 854252.34 10184287.38 2964.33 Southwest

Currently, there are flowlines and umbilicals northeast and south of MC 934, Proposed Location A-10 

associated with Shell’s Europa Field. Proposed Location A-10 will not interfere with these flowlines and 

umbilicals. 

Conclusion: 

 Based on a high-resolution geophysical survey, consisting of frequency enhanced 3-D seismic, Enhanced 

Surface Renderings (ESR’s), ESR’s with amplitudes applied, AUV data consisting of Side Scan Sonar and SubBottom Profiler, MC 934, Proposed Location A-10 appears suitable for the planned activity. 

Site Assessment, MC 934, Proposed Location A-11

Mississippi Canyon 934, Proposed Location A-11 is located in a water depth of approximately 3853 feet. 

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

within 2000 feet of MC 934, Proposed Location A-11. 

The stratigraphy at the site of MC 934, Proposed Location A-11 consists of: 

• Unit 1 (Seafloor – 371‘BML) consists of normal marine drape, hemipelagic mud and muddy mass 

transport deposits (MTD’s).

• Unit 2 (371’ – 649’ BML) consists of 278’ of muddy MTD’s

• Unit 3 (619’ – 1158’ BML) consists of 509’ of MTD’s with a thin sand package 

• Unit 4 (1158’ – 1591’ BML) consists of 433/ of MTD’s, conformable turbidites with some silty 

sections 

• Unit 5 (1591’ – 1903’ BML) consists of 312’ of muddy channel system that has mostly eroded “Blue 

Unit”

• Unit 6 (1903’ – 2497’ BML) consists of 594’ of muddy MTD’s with silty sand at the base

• Unit 7 (2497’ – 2726’BML) consists of Muddy MTD’s and conformable turbidites 

• Unit 8 (2726’ – 3637’ BML) consists of 911’ of regional MTD’s with sands and silts

• Unit 9 (3637’ – 4475’ BML) consists of 838’ of muddy MTD’s and conformable turbidites with some 

thin sand packages. 

Shallow Water Flow Potential: 

 Low Potential – Seafloor – 649’ BML

 Moderate Potential – 649’ – 1903’ BML

 Moderately Low Potential – 1903’ – 2497’ BML

 Low Potential – 2497’ – 4475’ BML

Shallow Gas Potential: 

 Low Potential – Seafloor – 4475’ BML

Chemo/Anchor Assessment, MC 934, Proposed Location A-11 (No Anchors – DP Vessel) 

Mississippi Canyon 934, Proposed Location A-11 is located in a water depth of approximately 3853 feet. 

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

within 2000’ of MC 934, Proposed Location A-11. MC 934, Proposed Location A-11 will not disturb any highdensity areas of benthic communities. 

Page 31 Public Information Copy
The following table consisting of 5 targets is a listing of marine avoidance zones identified within 2000’ of MC 

934, Proposed Location A-11: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc A-11

Direction from 

Prop Loc A-11

999 100’ 851619.02 10182629.61 499.35 Southeast

1111 100’ 852834.07 10182390.00 843.78 Southwest

935 100’ 851201.66 10182595.67 846.30 Southeast

1133 100’ 853112.40 10182743.67 1201.89 Southwest

1141 100’ 853240.60 10183144.34 1504.24 Southwest

The following table consisting of 29 targets, is a listing of barrels identified within 2000’ of MC 934, Proposed 

Location A-11: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc A-11

Direction from 

Prop Loc A-11

1001 50’ 851696.28 10182069.09 378.17 Northeast

981 50’ 851516.56 10182325.08 479.05 Southeast

972 50’ 851463.70 10182240.74 534.71 Northeast

973 50’ 851465.40 10182421.19 543.07 Southeast

980 50’ 851506.46 10182573.12 559.21 Southeast

969 50’ 851441.45 10182671.66 666.19 Southeast

1101 50’ 852755.67 10182564.28 804.94 Southwest

938 50’ 851222.80 10182762.64 899.67 Southeast

1115 50’ 852899.54 10182212.13 908.90 Northwest

951 50’ 851292.38 10182882.96 912.33 Southeast

1117 50’ 852929.23 10182409.19 940.47 Southwest

937 50’ 851221.82 10182901.20 978.80 Southeast

1007 50’ 851737.19 10183287.59 1019.72 Southeast

1096 50’ 852649.11 10181257.73 1231.37 Northwest

1136 50’ 853130.85 10182852.83 1262.80 Southwest

877 50’ 850696.13 10182321.85 1299.04 Southeast

856 50’ 850491.55 10182377.29 1505.38 Southeast

1145 50’ 853282.34 10183088.31 1509.01 Southwest

849 50’ 850405.10 10181839.82 1655.44 Northeast

845 50’ 850373.58 10181875.65 1676.28 Northeast

1163 50’ 853695.48 10182275.07 1700.68 Northwest

1023 50’ 851846.31 10180571.81 1735.57 Northeast

960 50’ 851391.16 10183940.64 1747.30 Southeast

1008 50’ 851737.61 10180572.66 1747.40 Northeast

932 50’ 851120.16 10180748.44 1782.07 Northeast

1178 50’ 853865.72 10182464.77 1877.87 Southwest

908 50’ 850890.65 10183836.73 1891.57 Southeast

860 50’ 850536.23 10181062.48 1913.62 Northeast

1181 50’ 853925.37 10182472.00 1937.93 Southwest

The following table consisting of 2 targets is a listing of marine avoidance zones identified within the 1000’ 

buffer zone (2000’ – 3000’) for MC 934, Proposed Location A-11. 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc A-11

Direction from 

Prop Loc A-11

1124 100’ 852977.59 10184541.35 2446.35 Southwest

765 100’ 849566.97 10183027.12 2534.28 Southeast

Page 32 Public Information Copy
The following table consisting of 45 targets is a listing of barrels identified within the 1000’ buffer zone (2000’ 

– 3000’) for MC 934, Proposed Location A-11.

Avoidance 

Zone Number Avoidance Size

Central X

Coordinate

Central Y 

Coordinate

Distance from

Prop Loc A-11

Direction from 

Prop Loc A-11

966 50’ 851420.30 10180345.79 2037.92 Northeast

963 50’ 851414.15 10180342.93 2042.41 Northeast

882 50’ 850739.17 10183968.55 2087.54 Southeast

1079 50’ 852421.02 10184355.33 2098.04 Southwest

815 50’ 850113.56 10181295.52 2133.26 Northeast

784 50’ 849805.72 10182659.94 2218.51 Southeast

965 50’ 851415.58 10180149.92 2227.75 Northeast

964 50’ 851415.16 10180140.45 2237.00 Northeast

843 50’ 850366.45 10180704.71 2280.42 Northeast

778 50’ 849707.04 10182559.18 2302.48 Southeast

777 50’ 849683.08 10182221.43 2313.29 Northeast

1168 50’ 853729.69 10183859.84 2332.19 Southwest

767 50’ 849580.66 10182286.12 2414.39 Northeast

1175 50’ 853841.43 10183889.72 2435.84 Southwest

762 50’ 849560.35 10182215.55 2436.15 Northeast

888 50’ 850751.31 10184400.19 2439.95 Southeast

1169 50’ 853774.27 10184059.85 2501.87 Southwest

998 50’ 851613.43 10184826.55 2554.21 Southeast

1207 50’ 854317.81 10183364.46 2554.68 Southwest

759 50’ 849537.82 10183012.94 2558.24 Southeast

748 50’ 849436.38 10182115.87 2565.31 Northeast

745 50’ 849421.05 10182412.77 2576.38 Southeast

752 50’ 849476.05 10182978.63 2608.50 Southeast

772 50’ 849613.20 10183408.72 2626.79 Southeast

1180 50’ 853916.16 10184132.33 2654.17 Southwest

979 50’ 851506.17 10179689.89 2656.47 Northeast

741 50’ 849355.29 10182671.06 2665.52 Southeast

747 50’ 849431.57 10183060.77 2673.65 Southeast

1228 50’ 854680.44 10182377.83 2686.54 Southwest

809 50’ 850067.26 10184224.24 2723.06 Southeast

732 50’ 849288.78 10181857.37 2742.34 Northeast

1233 50’ 854737.68 10182406.86 2744.72 Southwest

1187 50’ 853996.47 10184230.93 2780.38 Southwest

875 50’ 850657.41 10184750.78 2791.16 Southeast

740 50’ 849350.29 10183198.19 2792.75 Southeast

796 50’ 849908.87 10184160.86 2794.82 Southeast

1192 50’ 854052.80 10184241.79 2828.64 Southwest

1026 50’ 851872.88 10179469.91 2833.72 Northeast

726 50’ 849237.89 10181623.74 2839.07 Northeast

816 50’ 850116.06 10184431.34 2840.56 Southeast

1243 50’ 854845.64 10182370.78 2851.49 Southwest

1030 50’ 851891.72 10179366.34 2936.48 Northeast

1194 50’ 854066.33 10184446.18 2981.98 Southwest

1239 50’ 854791.72 10183370.69 2994.31 Southwest

722 50’ 849195.82 10181219.47 3000.85 Northeast

Currently, there are flowlines and umbilicals northeast and south of MC 934, Proposed Location A-11 

associated with Shell’s Europa Field. Proposed Location A-11 will not interfere with these flowlines and 

umbilicals. 

Page 33 Public Information Copy
Conclusion: 

 Based on a high-resolution geophysical survey, consisting of frequency enhanced 3-D seismic, Enhanced 

Surface Renderings (ESR’s), ESR’s with amplitudes applied, AUV data consisting of Side Scan Sonar and SubBottom Profiler, MC 934, Proposed Location A-11 appears suitable for the planned activity. 

Processing Platform

Existing Mississippi Canyon Block 807 (Mars) Platform 

 x = 924,373 3630' FNL 

y = 10,229,010 5653' FWL 

The Mars TLP will serve as the processing platform for the Mississippi Canyon Block 935 subsea wells. The 

MC807 platform is located in a water depth of approximately 2950 feet. A fault with seafloor expression is 

1450 feet west of this site. There is no evidence of fluid expulsion associated with this fault. None of the MC 

935 Unit wells will be drilled from the MC807 platform site for MC 935 Unit objectives. 

Proposed New Seafloor Hardware

Mississippi Canyon 934, Proposed Pile 2

 X = 851,860.26 

 Y = 10,182,417.67 

MC 934, Proposed Pile 2 is located in a water depth of approximately 3853 feet. There is no evidence of 

seafloor or near-surface faulting, slumping, amplitudes or fluid expulsion features within 250 feet of MC 934, 

Proposed Pile 2 will not disturb any high-density areas of benthic communities. 

There are no sonar targets identified within 250 feet of MC 934, Proposed Pile 2. 

Conclusion: 

 Based on a high-resolution geophysical survey, consisting of frequency enhanced 3-D seismic, Enhanced 

Surface Renderings (ESR’s), ESR’s with amplitudes applied, AUV data consisting of Side Scan Sonar and SubBottom Profiler, MC 934, Proposed Pile 2 appears suitable for the planned activity. 

See Waste Barrel Avoidance Plan at end of this section. 

B-F:

Pursuant to NTL No. 2008-G04 the proposed operations covered by this plan do not involve operations 

impacting the following: Topographic features map, Topographic features statement (shunting), Live 

bottoms, (Pinnacle Trend) map, Live bottoms (low relief) map, potentially sensitive biological features map. 

G. Remotely Operated Vehicle (ROV) Monitoring Plan

Mississippi Canyon Block 934 is located in Grid 13, which has adequate ROV coverage so in accordance with 

the provisions of NTL No. 2008-G06, Remotely Operated Vehicle Surveys in Deepwater, we are not proposing 

to run an ROV survey. 

H. Threatened and Endanger Species Information

There are 5 species of sea turtles that may be found in the Gulf of Mexico (see table). No critical habitat for 

these species has been designated in the Gulf of Mexico. 

Page 34 Public Information Copy
Common Name Scientific Name T/E Status

Hawksbill Turtle Eretmochelys imbricata E

Green Turtle Chelonia mydas T

Kemp's Ridley Turtle Lepidochelys kempii E

Leatherback Turtle Dermochelys coriacea E

Loggerhead Turtle Caretta caretta T

There are 28 species of marine mammals that may be found in the Gulf of Mexico (see table). Of the species 

listed as Endangered, only the Sperm whale is commonly found in the project area. No critical habitat for 

these species has been designated in the Gulf of Mexico. 

Common Name Scientific Name T/E Status

Atlantic Spotted Dolphin Stenella frontalis

Blainville's Beaked Whale Mesoplodon densirostris

Blue Whale Balaenoptera musculus E

Bottlenose Dolphin Tursiops truncatus

Bryde's Whale Balaenoptera edeni

Clymene Dolphin Stenella clymene

Cuvier's Beaked Whale Ziphius cavirostris

Dwarf Sperm Whale Kogia simus

False Killer Whale Pseudorca crassidens

Fin Whale Balaenoptera physalus E

Fraser's Dolphin Lagenodelphis hosei

Gervais' Beaked Whale Mesoplodon europaeus

Humpback Whale Megaptera novaeangliae E

Killer Whale Orcinus orca

Melon-headed Whale Peponocephala electra

Minke Whale Balaenoptera acutorostrata

Northern Right Whale Eubalaena glacialis

Pantropical Spotted Dolphin Stenella attenuata

Pygmy Killer Whale Feresa attenuata

Pygmy Sperm Whale Kogia breviceps

Risso's Dolphin Grampus griseus

Rough-toothed Dolphin Steno bredanensis

Sei Whale Balaenoptera borealis E

Short-finned Pilot Whale Globicephala macrorhynchus

Sowerby's Beaked Whale Mesoplodon bidens

Sperm Whale Physeter macrocephalus E

Spinner Dolphin (Long-snouted) Stenella longirostris

Striped Dolphin Stenella coeruleoalba

Page 35 Public Information Copy
I. Archaeological Report

Archaeological Conclusion: 

C&C Technologies, Shell Exploration and Production Archaeological and Hazard Report, Blocks 

890-979, Mississippi Canyon Area, U.S. Gulf of Mexico, dated October, 2010, Project #100231-

100420. Data: AUV data consisting of side scan sonar and sub-bottom profiler 

Data assessment for a multi-block survey located 2,600 unidentified sonar contacts. The seafloor pattern and 

acoustic characteristics of 2,227 of these targets suggest they could be “potential barrels” or other kinds of 

containers dumped in the survey area by organized disposal operations. Once sonar contact represents the 

wreck of what appears to be a modern commercial or pleasure fishing vessel that is not considered to be 

archaeologically significant. A hazard avoidance of 500 feet is recommended for this shipwreck. The 

remaining 373 sonar contacts are interpreted as modern debris associated primarily with industrial waste 

dumping or field development activities. Archaeological avoidance or investigation is not recommended for 

any of the 2,600 sonar contacts. It is possible a shipwreck exists undetected or unidentified within the 

survey area. If wood beams, planking, ceramics, or other possible cultural materials are encountered during 

lease development, the BOEMRE archaeologists must be contacted within 48 hours for an assessment of any 

antiquities. In this event, no activities should be conducted near the area or discovery until advised by the 

appropriate BOEM personnel. 

Fugro-Geoservices, Inc., Shell Deepwater Development Systems, Inc., Archaeological 

Assessment, Blocks 890-892, 934-936, & 978-980, Mississippi Canyon Area, Gulf of Mexico, 

Report #2405-1366, dated December, 2005. Data: Deep-towed Side Scan Sonar and Subbottom Profiler 

The evaluation of the high-resolution geophysical survey data collected within the survey area indicates that 

one shipwreck is located within MC892. The wreck should be avoided by at least 1,000 feet when working in 

the vicinity of this feature. The remaining portions of the study area are clear of unusual depressions, scours, 

sediment changes, and unidentified seafloor targets that could represent unidentified shipwreck remains. 

There were also no unidentified hyperbolae on the subbottom profiler records. 

It is possible that historic shipwreck materials may not be detected by the geophysical instruments or may be 

obscured by modern debris. If wooden planking or other cultural materials that could represent shipwreck 

remains are encountered, the USDI BOEM archaeologists should be contacted to provide an assessment of 

these artifacts. 

Page 36 Public Information Copy
J. Air and Water Quality Information

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

additional information relating to air and water quality information. For specific information relating to air 

and water quality information please refer to the EIA, Attachment 18. 

K. Socioeconomic Information

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

additional information relating to socioeconomic information. For specific information relating to 

socioeconomic information please refer to the EIA, Attachment 18. 

Page 37 Public Information Copy
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 

Page 38 Public Information Copy
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 

Page 39 Public Information Copy
Document Number -Rev Page 3 of 8 

RESTRICTED

Contents 

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

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

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

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

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

Page 40 Public Information Copy
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

4 of 8 

Purpose 

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

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

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

contents. 

Applicability 

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

barrel rupture. 

Changes to this procedure must be approved by BOEMRE.1 

Revision History 

Date Person Revision 

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

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

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

Also revised all relevant references to MMS as BOEMRE 

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

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

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

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

NPDES Vessel General Permit as a guide. 

o Expanded on appropriate PPE and other personnel precautions 

o Noted a need for secondary containment as appropriate 

Significant changes to the text are shown in yellow shade. 

3⁄4 Added page numbers and cleaned up format. 

 

3⁄4 Issued as REV 2 

Background 

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

barrels of chemical waste. 

 

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

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

Mississippi Canyon Area

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

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

Mississippi Canyon Area

3

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

Page 41 Public Information Copy
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

5 of 8 

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

permits. 

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

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

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

barrel contents based on available records. 

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

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

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

and herbicides”.5

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

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

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

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

intact may still contain some waste. 

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

Potential Hazards 

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

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

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

recovered subsea equipment 

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

Normal Operations 

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

expectations: 

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

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

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

 

4

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

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

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

to dispose of the following at the ocean disposal site

Page 42 Public Information Copy
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

6 of 8 

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 

Page 43 Public Information Copy
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

7 of 8 

Based on various factors6

, Shell recommends the following: 

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

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

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

that’s possible, again avoiding seafloor dragging. 

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

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

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

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

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

only minimally caustic and should be biodegradable7. 

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

this point.. 

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

minutes. 

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

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

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

contact. Rewash and dunk the equipment as needed. 

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

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

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

to collect any potentially contaminated drips. 

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

back deck. 

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

potentially contaminated surfaces, personal protective equipment must be worn 

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

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

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

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

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

7

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

washing. Also, EPA provides the following definitions: 

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

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

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

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

Page 44 Public Information Copy
Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area 

10/20/10 REV 2 

8 of 8 

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

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

the equipment. 

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

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

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

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

sheeting, etc. 

2.13. Document all actions and results in a log. 

Barrel Impact Reporting 

1. Initial reporting:

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

operations supervisor on duty. 

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

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

281-0783 (Rob Kuehn). 

• The call should be made at the earliest convenience. 

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

and water depth. 

2. The SEPCO Environmental Duty Engineer will call 

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

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

• BOEMRE New Orleans District Manager 

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

3. Follow-up Reporting

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

Mr. Broussard of BOEMRE. 

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

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

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

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

Page 45 Public Information Copy
Attachment 6A – ESR for Well A10

Page 46 Public Information Copy
Attachment 6B – ESR for Well A11

Page 47 Public Information Copy
SECTION 7: WASTE AND DISCHARGE INFORMATION

A. Projected Generated Wastes 

Type of Waste and Composition Composition Projected Amount Discharge rate 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 94,600 bbls/well 26,650 bbls/day Seafloor discharge prior to marine riser installation No

Cuttings wetted with water-based fluid Cuttings coated with water based drilling mud 1,890 bbls/well 530 bbls/day Seafloor discharge prior to marine riser installation No

Cuttings wetted with synthetic-based fluid 

Cuttings generated while using synthetic 

based drilling fluid 4,491 bbls/well 250 bbls/day Cuttings chute below MSL No

Synthetic based drilling fluid adhering to washed drill 

cuttings

Synthetic based drilling fluid adhering to 

washed drill cuttings 180 bbls/well 10 bbls/day Cuttings chute below MSL No

Spent drilling fluids - synthetic Synthetic-based drilling mud NA NA NA No

Chemical product waste Chemical product waste NA NA NA 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 30,530 bbls/well 215 bbls/day

Ground to less than 25 mm mesh size and 

discharge overboard No

Sanitary waste (toilet water) treated sanitary waste 10,224 bbls/well 72 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 Wash and rainwater 1,420 bbls/well 10 bbls/day Drained overboard through deck scuppers No

Will you conduct well treatment, completion, or workover? 

Well Treatment Fluids

Water based frac fluids. Solvent based pipe 

pickle 2,000 bbls/well 50 bbls/well

Frac fluids will be injected in the well during the 

completion and will be flowed back to the host 

facility when the well is brought online. Returns 

will be minimal and will undergo static sheen 

testing and monthly grease compliance testing 

prior to discharge overboard. Pipe pickle to be No

Well Completion Fuids Calcium Bromide brine 1,500 bbls/well 1,500 bbls/well

Base plan is to catch all brine and return onshore 

for reclaim. In the event that this cannot 

happen, returns will undergo static sheen 

testing and monthly grease compliance testing 

prior to discharge overboard. No

Well Clean Up Fluids

Base oil 

Transition Spacer 

Solvent based sweep 

Viscous Spacer 

NaCl brine (riser clean out) CaBr2 

Brine (wellbore clean out) 3,000 bbls/well 3,000 bbls/well

Base oil will be caught with SBM and taken 

onshore. Transition Spacer will be caught and 

taken onshore for disposal.Solvent based sweep 

will be caught and taken onshore for disposal. 

Viscous spacer and NaCl will undergo static sheen 

testing and monthly grease compliance and be 

discharged overboard. CaBr2 will be reclaimed. No

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

Desalinization unit discharge Rejected water from watermaker unit 1,420 bbls/well 10 bbls/day Discharged overboard 35 feet below waterline No

Blowout prevent fluid Water based 85.2 bbls/well 0.6 bbls/day Disharge at seafloor No

Ballast water Uncontaminated seawater 312,400 bbls/well 2,200 bbls/day Discharged overboard just above waterline No

Bilge water

Bilge and drainage water will be treated to 

MARPOL standards (< 15ppm oil in water). 26,270 bbls/well 185 bbls/day

Bilge and drainage water will be treated to 

MARPOL standards (< 15ppm oil in water). No

Excess cement at seafloor Cement slurry

 450 bbls/well (assume planned 

100% excess is discharged) 450 bbls/well Discharged at the seafloor during riserless drilling No

Fire water Treated seawater 9,460 bbls/well 2,000 bbls/month Drained overboard through deck scuppers No

Cooling water Treated seawater 61,288,620 bbls/well 431,610 bbls/day Discharged overboard 40 feet below waterline No

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

Produced water NA NA NA NA NA

Will you be covered by an individual or general NPDES permit ? Yes GENERAL PERMIT GMG290103

TABLE 7A: WASTES YOU WILL GENERATE, TREAT AND DOWNHOLE DISPOSE OR DISCHARGE TO THE GOM

Projected Downhole 

Projected generated waste Projected ocean discharges Disposal

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

Page 48 Public Information Copy
B. Projected Ocean Discharges 

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 or dedicated tanks on support 

vessels MI Drilling Fluids - Fourchon, LA 7,000 bbls/well Recycled

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

Cuttings wetted with Synthetic-based fluid 

Drill cuttings from synthetic 

based interval. Storage tank on supply boat Newpark Environmental, Ingleside, TX 150 bbls / well Recycled

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

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

Produced sand

NA- this well has sand 

control NA NA NA NA

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

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

Omega Waste Management, W. 

Patterson, LA or ARC, New Iberia, LA 22,400 lbs/well 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 11,200 lbs/well Landfill

used oil used oil Drums on supply boat

Omega Waste Management, W. 

Patterson, LA or ARC, New Iberia, LA 55 bbls/well Incinerate

Chemical product wastes Solvent

Captured at surface in MPT tanks, 

transported onshore for disposal in an 

environmentally friendly manner.

Safety Kleep, Denton, TX or Lamp 

Environmental, Hammond, LA 150 bbls/well Recycled

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

Revised DOCD: Europa A10 and Europa A-11

C. Modeling Report

 Not applicable to this Plan. 

Page 49 Public Information Copy
SECTION 8: AIR EMISSIONS INFORMATION

A. Emissions Worksheet and Screening Questions 

Screening Questions for DOCD’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*

Does or will the facility complex associated with your proposed development and 

production activities process production from eight or more wells?

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 in excess of the criteria set forth under 

250.1105(a)(2) and (3)?

X

Do you propose to burn produced hydrocarbon liquids? X

Are your proposed development and production activities located within 25 miles 

from shore?

X

Are your proposed development and production activities located within 200 

kilometers of the Breton Wilderness Area?

X

*Actual fuel usage values were utilized to reduce the worst-case emissions below the 

BOEM exemption thresholds. See attached worksheets.

B. If you answer no to all of the above screening questions from the appropriate table, 

provide: 

(1) Summary information regarding the peak year emissions for both Plan Emissions and 

Complex Total Emissions, if applicable. This information is compiled on the summary form 

of the two sets of worksheets. You can submit either these summary forms or use the 

format below. You do not need to include the entire set of worksheets. 

Air Pollutant Plan 

EmissionAmounts

(tons)

Calculated 

Exemption

Amounts 

(tons)

Calculated

Complex Total 

Emission 

Amounts

(tons)

Carbon monoxide CO

Particulate matter (PM)

Sulphur dioxide (SO2)

Nitrogen oxides (NOx)

Volatile organic compounds (VOC)

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

Page 50 Public Information Copy
Atwood Condor - Fuel Limit Basis

jbm – 03/20/2013

Step 1 - Determine typical operating loads

The Atwood Condor has eight main engines. With no weather conditions present and no heavy currents (i.e., steady-state conditions), the 

Condor utilizes roughly 30-40 cubic meters of fuel a day with 4 engines out of 8 total online with about 35% load on the engines.

See e-mail provided from Atwood for basis: See attached email

Step 2 - Identify Safety Factors and Overall Load Factor

Since minimal data is available for the Atwood Condor (newly built rig only recently put into operation), appropriate safety factors are utilized in 

conjunction with the data provided in Step 1.

Description Value Notes

PTE Fuel Use (gal/day) 62931

The Atwood Condor is equipped with 8 main engines at 6786 hp each. The PTE 

fuel use is then estimated using the AQR conversion factor of 0.0483 gal/hp-hr.

Operating Load - From Step 1 35% Note this is based on only 4 of 8 engines operating.

Proposed Operating Load - Across all 8 

Main Engines 40%

By applying the load evenly across all 8 engines, this should provide for 

conservative emission estimates. And additional 5% load was applied to the engine 

as well.

Proposed Campaign Average Daily 

Fuel Use (gal/day) 25172 Calculated Value - PTE fuel use * Proposed Operating Load

2014 Equivalent Campaign Total 

MODU Fuel Use (MMgals)

3.35

Calculated Value - Proposed Campaign Average Daily Fuel Use * Campaign 

Days 

2015 Equivalent Campaign Total 

MODU Fuel Use (MMgals)

3.35

Calculated Value - Proposed Campaign Average Daily Fuel Use * Campaign 

Days

Page 51 Public Information Copy
Step 3 - Other Vessel Fuel Loads

Description Value Notes

Proposed Operating Loads 50%

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

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

(25 nm), traveling at economical speeds. 

2014 Equivalent Campaign Total 

Vessel Fuel Use (MMgals) 1.07

Sum of the product of each vessel daily fuel use and the number of campaign 

days

2015 Equivalent Campaign Total 

Vessel Fuel Use (MMgals) 1.07

Sum of the product of each vessel daily fuel use and the number of campaign 

days

Additional Notes

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

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

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

calculations.

Page 52 Public Information Copy
From: Michael Morrow [mmorrow@atwd.com] 

Sent: Wednesday, November 14, 2012 12:35 PM 

To: McMenis, Jeffrey B SEPCO-UAS/E/USOFF 

Cc: Wullie Strachan; Sorgard, Eirik SIEP-PTW/DGO 

Subject: FW: Rig Environmental Questionnaire - Atwood Condor 

Categories: AQRs 

Jeff, 

As discussed on the phone, see the below concerning the average fuel consume during a normal 

situation on the Condor. 

With no weather conditions present and no heavy currents, we are burning roughly 30-40 cubic 

meters of fuel a day with 4 engines out of 8 total online with about 35% load on the engines. 

Let us know if you would like the values for a different situation or scenario. 

Kind Regards, 

MICHAEL MORROW ●● Operations Engineer – Atwood Condor 

Houston: Cell: (+1) 281-203-9454 Houston: Office: (+1) 281-749-7806 mmorrow@atwd.com www.atwd.com

From: Condor RMS 

Sent: Tuesday, November 13, 2012 7:44 PM 

To: Michael Morrow 

Subject: FW: Rig Environmental Questionnaire - Atwood Condor 

Mike, 

FYI 

Regards, 

Gordon Hynes 

Maintenance Supervisor 

Atwood Condor 

Office +1 281 749-8664 

E-mail condor_rms@atwd.com

From: Condor Chief Engineer 

Sent: Tuesday, November 13, 2012 6:19 PM 

To: Condor RMS 

Subject: RE: Rig Environmental Questionnaire - Atwood Condor 

Gordon, 

Looking back at the reports with no weather conditions present and no heavy currents, we are 

burning roughly 30-40 cubic meters of fuel a day with 4 engines online with about 35% load on the 

engines. 

Regards, 

Page 53 Public Information Copy
Matt 

Atwood Condor

Condor_Chief@atwd.com

www.atwd.com

From: Condor RMS 

Sent: Tuesday, November 13, 2012 8:53 AM 

To: Condor Chief Engineer 

Subject: FW: Rig Environmental Questionnaire - Atwood Condor 

Matt, 

Maybe you can calculate this up tonight? 

Thanks 

Regards, 

Gordon Hynes 

Maintenance Supervisor 

Atwood Condor 

Office +1 281 749-8664 

E-mail condor_rms@atwd.com

Page 54 Public Information Copy
COMPANY Shell Offshore Inc.

AREA Mississippi Canyon

BLOCK 934

LEASE OCS-G-7975

PLATFORM MODU

WELL A8, A9

COMPANY 

CONTACT Jeff McMenis

TELEPHONE NO. 504-425-6021

REMARKS SEPCO Env File Name - Europa_AQR_DOCD_Condor_111612.xlsx

Page 55 Public Information Copy
Fuel Usage Conversion Factors Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine REF. DATE

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Glycol Dehydrator Vent lbs/mmscf 6.6 La. DEQ 1991

Gas Venting lbs/scf 0.0034

Sulphur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.05 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

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

maximum sulfur, effective June 1, 2007.

Page 56 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

 Shell Offshore Inc. Mississippi Canyon 934 OCS-G-7975 MODU A10, A11 Jeff McMenis 504-425-6021 SEPCO Env File Name - Europa_AQR_DOCD_Condor_032013.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 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

Energency Generator>600hp 

diesel 1910 92 100% 2214 1 19 1.35 0.77 46.28 1.39 10.10 0.01 0.01 0.44 0.01 0.10

AUXILIARY EQUIP<600hp diesel 

(startup air compressor ) 10 0.5 100% 12 1 19 0.02 0.004 0.31 0.02 0.07 0.0002 0.00004 0.0029 0.0002 0.0006

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

Supply Vessel>600hp diesel 

(general support) 9440 456 50% 5471 24 133 6.65 3.82 228.72 6.86 49.90 5.31 3.04 182.52 5.48 39.82

Crew Vessel>600hp diesel 5400 261 50% 3130 24 40 3.81 2.18 130.84 3.93 28.55 0.91 0.52 31.40 0.94 6.85

Supply Vessel>600hp diesel 

(spud activity) 9440 456 50% 5471 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

Supply Vessel>600hp diesel 

(spud activity) 9440 456 50% 5471 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

Ocean Service Jumper Vessel > 

600hp Diesel 25411 1227 50% 14728 24 7 17.91 10.27 615.69 18.47 134.33 0.75 0.43 25.86 0.78 5.64

FACILITY

INSTALLATION

MISC. BPD SCF/HR COUNT

TANKDRILLING OIL BURN

WELL TEST GAS FLARE

2014 YEAR TOTAL 81.31 46.62 2794.62 83.85 609.74 32.22 18.47 1107.39 33.22 241.61

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 2031.30 2031.30 2031.30 2031.30 52686.43

61.0

Average 

Engine 

Loads %

Page 57 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

 Shell Offshore Inc. Mississippi Canyon 934 OCS-G-7975 MODU A10, A11 Jeff McMenis 504-425-6021 SEPCO Env File Name - Europa_AQR_DOCD_Condor_032013.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 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

PRIME MOVER>600hp diesel 6786 328 40% 3147 24 133 4.78 2.74 164.42 4.93 35.87 3.05 1.75 104.96 3.15 22.90

Energency Generator>600hp 

diesel 1910 92 100% 2214 1 19 1.35 0.77 46.28 1.39 10.10 0.01 0.01 0.44 0.01 0.10

AUXILIARY EQUIP<600hp diesel 

(startup air compressor ) 10 0.5 100% 12 1 19 0.02 0.00 0.31 0.02 0.07 0.00 0.00 0.00 0.00 0.00

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

Supply Vessel>600hp diesel 

(general support) 9440 456 50% 5471 24 133 6.65 3.82 228.72 6.86 49.90 5.31 3.04 182.52 5.48 39.82

Crew Vessel>600hp diesel 5400 261 50% 3130 24 40 3.81 2.18 130.84 3.93 28.55 0.91 0.52 31.40 0.94 6.85

Supply Vessel>600hp diesel 

(spud activity) 9440 456 50% 5471 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

Supply Vessel>600hp diesel 

(spud activity) 9440 456 50% 5471 24 10 6.65 3.82 228.72 6.86 49.90 0.40 0.23 13.72 0.41 2.99

Ocean Service Jumper Vessel > 

600hp Diesel 25411 1227 50% 14728 24 7 17.91 10.27 615.69 18.47 134.33 0.75 0.43 25.86 0.78 5.64

FACILITY

INSTALLATION

MISC. BPD SCF/HR COUNT

TANKDRILLING OIL BURN

WELL TEST GAS FLARE

2015 YEAR TOTAL 81.31 46.62 2794.62 83.85 609.74 32.22 18.47 1107.39 33.22 241.61

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 2031.30 2031.30 2031.30 2031.30 52686.43

61.0

Average 

Engine 

Loads %

Page 58 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore 

Inc.

Mississippi 

Canyon 934 OCS-G-7975 MODU A10, A11

Emitted Substance

Year

PM SOx NOx VOC CO

2014 32.22 18.47 1107.39 33.22 241.61

2015 32.22 18.47 1107.39 33.22 241.61

Allowable 2031.30 2031.30 2031.30 2031.30 52686.43

Page 59 Public Information Copy
SECTION 9: OIL SPILL INFORMATION

A. Oil Spill Response Planning

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

Shell Offshore Inc. (0689) in accordance with 30 CFR 550 and 30 CFR 254, and approved by BSEE in 

April 2013. As show in the comparison table below, the operations proposed in this plan do not 

exceed the certificate amount on file with BSEE. 

Spill Response Sites: 

Primary Response Equipment Location Preplanned Staging Location(s)

Venice, LA; Houma, LA; Pascagoula, MS; 

Fort Jackson, LA

Fourchon, LA; Pascagoula, MS; Fort 

Jackson, LA; Venice, LA

OSRO Information: 

The names of the oil spill removal organizations (OSRO’s) under contract include Clean Gulf 

Associates (CGA), Marine Spill Response Company (MSRC), Clean Caribbean America (CCA), and 

OSRL/EARL. 

Worst Case Scenario Determination: 

Drilling Production

Category Regional OSRP DOCD Regional OSRP DOCD

Type of Activity Subsea 

Drilling

Europa A7

Drilling

Production >10 

miles to shore

Production >10 

miles to shore

Facility Location (area/block) MC 391 MC 935 MC 807 MC 935

Facility Designation Subsea well 1◊ Subsea well #A7◊◊◊ MB001◊◊ A7

Distance to Nearest Shoreline (miles) 70 61 53 61

Volume

Storage tanks (total)

Flowlines (on facility)

Pipelines

Uncontrolled blowout (volume per day)

Total Volume

N/A

N/A

N/A

416,414* BOPD

416,414 BOPD

N/A

N/A

N/A

207,677** BOPD

207,677** BOPD

11,163 Bbls

100 Bbls

1,604 Bbls

446,000*** BOPD

458,867 Bbls

0 Bbls

100 Bbls

8,679 Bbls

19,250 BOPD

28,029 Bbls

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

diesel)

Crude oil Crude oil Crude Oil Crude Oil

API Gravity(s) 26o 37.5 o 26o 37.5o

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

 **24 hour rate (134,011 BOPD 30 day average rate) 

***24 hour rate (359,500 BOPD 30 day average rate) 

◊This well was reviewed and accepted by BOEM in plan S-7444 (May 2011) and accepted by BSEE during the drilling 

of the well. The 30-day average was updated in update to the OSRP July 2012. 

◊◊This well was review and accepted by BOEM in plan S-7499.

◊◊◊ This well was review and accepted by BOEM in plan S-7405. The WCD for wells in this plan do not exceed this 

WCD number. See section 2J of this plan.

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

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

Plan does not replace the appropriate worst-case scenario in our regional OSRP, I hereby certify that Shell 

Offshore Inc. has the capability to respond, to the maximum extent practicable, to a worst-case discharge, 

or a substantial threat of such a discharge, resulting from the activities proposed in our DOCD. 

Page 60 Public Information Copy
B. Oil Spill Response Discussion 

1. Volume of the Worst Case Discharge 

Please refer to Section 2J of this plan. 

2. Trajectory Analysis 

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

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

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

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

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

Area/Block

MC 935

OCSG7976Launch

Area Land Segment Contact %

> 10 Miles

from Shoreline

MC 935

58

GALVESTON, TX

JEFFERSON, TX

CAMERON, LA

VERMILION, LA

IBERIA, LA

TERREBONNE, LA

LA FOURCHE, LA

JEFFERSON, LA

PLAQUEMINES, LA

ST. BERNARD, LA

OKALOOSA, FL

1

1

3

2

1

3

3

1

8

1

1

Table 9.C.1 Probability of Land Segment Impact 

3. 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 atrisk 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 WCD scenario. 

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

within the Gulf of Mexico for the 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 and one Wildlife Management Area 

including the Breton National Wildlife Refuge, the Delta National Wildlife Refuge, and the Pass a 

Loutre Wildlife Management Area. Key ESI maps for Plaquemines Parish and the legend are 

shown in Figures 9.C.1, 9.C.2, 9.C.3, 9.C.4, and 9.C.5. 

Page 61 Public Information Copy
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. 

4. Worst Case Discharge Response 

Shell will make every effort to respond to the Worst Case Discharge as effectively as possible. 

Applied Science Associates (ASA) conducted a deepwater blowout simulation to better determine 

subsurface and surface evaporation and dispersion rates. Below is a table outlining the applicable 

evaporation and dispersion quantities. 

Mississippi Canyon Block 935

Calculations

(BBLS)

i. 30 Day Average WCD = 134,011

ii. Surface dispersion and evaporation – 25% -33,503

TOTAL REMAINING ~100,508 bbls

Table 9.D.1 Oil Remaining After Subsurface and Surface Dispersion 

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

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

adverse weather conditions, major response vessels and Transrec skimmers are still effective and 

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

natural dispersion and airborne chemical dispersant application (visibility & wind conditions 

permitting) may be the only safe and viable recovery option. 

MSRC OSRV 8 foot seas

VOSS System 4 foot seas

Expandi Boom 6 foot seas, 20 knot winds

Dispersants Winds more than 25 knots,

Visibility less than 3 nautical miles, or

Ceiling less than 1,000 feet.

Table 9.D.2 Operational Limitations of Response Equipment 

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

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

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

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

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

The Incident Commander or designee may contact other service companies if the Unified 

Command deems such services necessary to the response efforts. 

Page 62 Public Information Copy
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 935 will be addressed in Shell’s NTL10 submission at the time the APD is submitted.

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 

865,993 barrels/day. Temporary storage associated with the identified skimming and temporary 

storage equipment equals approximately 836,574 barrels. 

De-rated Recovery Rate

(bopd)

Storage

(bbls)

Offshore Recovery and 

Storage 663,709 856,061

Nearshore Recovery and 

Storage 184,807 5,130

Total 848,516 861,191

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

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

Table 9.D.5 Offshore On-Water Storage Activation List 

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

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

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

any other tanker immediately available). The recovered oil would be transferred to Motiva’s 

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

facility.

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

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

Table 9.D.7 Aerial Surveillance Activation List

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

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

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

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

King Air and 3 to 4 sorties from the Hercules C-130A within the first 12 hour operating day of the 

response could disperse 4,600 to 6,100 barrels of oil per day. For continuing dispersant 

operations, the CCA’s Aerial Dispersant Delivery System (ADDS) would be mobilized. The ADDS 

has a dispersant spray capability of 5,000 gallons per sortie. 

 Table 9.D.8 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.9 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.

Page 63 Public Information Copy
 Table 9.D.10 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 aerially-deployed 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.11 In-Situ Burn Equipment Activation List 

 Shoreline Protection: If the spill went unabated, shoreline impact in St. Bernard or 

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, 

The Response Group and Unified Command would be consulted to ensure that environmental 

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

protection. The Response Group shoreline response guides depict the protection response modes 

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

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

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

allowing a more effective response to site-specific circumstances. 

 Table 9.D.12 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 the 

following table: 

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

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Estimated Time for Spill Response and to Contain to the Maximum Extent Possible: 

According to Table 9.D.4, it is estimated that the first spill response equipment will arrive on 

scene in approximately 11 hrs from notification. Shell’s estimate, based on the anticipated worst 

case discharge scenario, is that we can have dedicated, contracted oil spill recovery equipment 

with adequate response capacity based on the equipment’s Estimated Daily Response Capacity 

(EDRC) on site within 22 hours which includes mechanical oil recovery and storage. Shell will 

continue to ramp up additional on-water mechanical recovery resources as well as deploy aerial 

dispersant and in-situ burn resources as needed and as approved under the supervision of the 

USCG Captain of the Port (COTP) and the Regional Response Team (RRT). 

Additionally, in the event of a sustained well control event, Shell will deploy a capping stack and 

can be in position to commence capping and containment operations in an estimated 10-14 

days. 

This is Shell’s best estimates with full recognition that times to respond and effectiveness can be 

affected by uncontrollable factors such as weather and sea state.

Shell estimates the time to contain the WCD to the maximum extent practicable, and prevent 

impacts to coastal resources, is approximately 24 hours. 

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. 

C. Modeling Report 

 Not applicable to this plan. 

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Figure 9.C.1 Environmental Sensitivity Index Map Legend 

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Figure 9.C.2 South Pass ESI Map 

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Figure 9.C.3 Garden Island Pass ESI Map 

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. 

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

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Figure 9.C.5 Main Pass ESI Map 

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SECTION 10: ENVIRONMENTAL MONITORING INFORMATION

A. Monitoring Systems 

A rig based Acoustic Doppler Current Profiler (ADCP) is used to continuously monitor the current beneath 

the rig. Metocean conditions such as sea states, wind speed, ocean currents, etc. will also be continuously 

monitored. 

B. Incidental takes 

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

believe that its operations proposed under this plan 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 

This block is not located in the Flower Garden Banks National Marine Sanctuary.

SECTION 11: LEASE STIPULATIONS INFORMATION

OCS-G 7975 is not a part of any Biological Sensitive Area, Shipping Fairway, or located in a Military Warning 

Area. It has been designated as having a high potential for containing archeological properties; see section 6 

of this plan for additional information. 

SECTION 12: ENVIRONMENTAL MITIGATION MEASURE INFORMATION

A. Impacts to Marine and coastal environments 

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

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

disposal, as well as any additional permit requirements and Shell policies. Project activities will be 

conducted in accordance with the Regional Oil Spill Response Plan. The EIA in Section 18 of this plan 

discusses impacts and mitigation measures. 

B. Incidental Takes 

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

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

notices to lessees and operators from 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”

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SECTION 13: RELATED FACILITIES

 AND OPERATIONS INFORMATION

Plans are to drill, complete and produce one to two new subsea wells. The new wells will be located at 

the existing manifold in MC 934. The oil will be commingled in the Europa manifold located in MC 934. 

It will then be transported 18 miles through an existing 8" x 12" pipe-in- pipe (pip) flowline system for 

processing at the existing Mars TLP in MC 807. 

Only drilling, completion, and subsea tie back activities will take place at this subsea location (MC 934) 

using a DP Rig for drilling and tree installation and a dynamically positioned intervention vessel for 

jumper, HFL, SLF, and EFL installation. 

The new well(s) will be controlled from the Mars TLP through the existing Europa electro-hydraulic 

umbilicals. The umbilicals will be utilized to deliver chemical and water-based hydraulic control fluid to 

the subsea wells and flowlines as well as to provide for multiplexed electrical control and monitoring of 

the subsea system. 

No expansion of the existing Mars TLP is anticipated as a result of the addition of these wells. There will 

be minor control system modifications to accommodate the new wells within the existing Europa control 

scheme. 

Transportation System

Oil Export 

Oil is exported from the Mars Platform via an existing 18", 41 mile pipeline to West Delta 143 platform. 

From the WD 143 platform oil is transported through an existing 24", 55-mile pipeline to Fourchon, La. 

Gas Export

Gas is exported from the Mars Platform via an existing 14", 41-mile pipeline to the West Delta 143 

platform. From the WD 143 platform gas is transported through an existing 30" pipeline to the Venice 

Gas Plant for processing. 

 Produced liquid hydrocarbons transportation vessels 

 Not applicable. 

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SECTION 14: SUPPORT VESSELS AND AIRCRAFT INFORMATION

A. General 

Type Maximum Fuel Tank 

Storage Capacity

Maximum No. In Area at 

Any Time

Trip Frequency or 

Duration

Jumper Installation Vessel 9,000 bbls. 1 10 days 

Supply Boats 9,750 bbls. 1 Twice weekly

Stand by Vessel 500 bbls. 1 Daily

Crew Boats 1,040 bbls. 1 Twice Weekly

Helicopters 22 bbls. 2 10 per week

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 per week Port Fourchon to MC 934

C. Drilling Fluids Transportation 

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

State of Florida. 

D. Solid and Liquid Wastes Transportation 

See Section 7, Table 7B. 

E. Vicinity Map 

 See Attachment 14A for Vicinity Map. 

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Attachment 14A – Vicinity Map 

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SECTION 15: ONSHORE SUPPORT FACILITIES INFORMATION

A. General 

Name Location Existing/New/Modified

C Port 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 project will not cause support base construction or expansion. 

C. Support Base Construction or Expansion Timetable 

Based on B above, this is not applicable to this Plan. 

D. Waste Disposal 

See Section 7, Table 7B. 

SECTION 16: SULPHUR OPERATIONS INFORMATION

Information regarding Sulfur Operations Information is not included in this plan as we are not proposing 

sulphur operations.

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1 

SECTION 17: COASTAL ZONE MANAGEMENT ACT (CZMA) INFORMATION

Louisiana coastal zone consistancy was obtained in 2013 in plan R-5746 for these leases 

and is not required for supplemental plans. 

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SECTION 18: ENVIRONMENTAL IMPACT ANALYSIS (EIA)

SUPPLEMENTAL DEVELOPMENT OPERATIONS COORDINATION DOCUMENT 

Mississippi Canyon Block 934 (OCS-G 7975) 

Offshore Louisiana 

August 2013 

Prepared for: 

Shell Offshore Inc. 

P.O. Box 61933 

New Orleans, Louisiana 70161 

Prepared by: 

CSA International, Inc. 

8502 SW Kansas Avenue 

Stuart, Florida 34997 

Telephone: (772) 219-3000 

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Introduction 

Project Summary 

Shell Offshore Inc. (Shell) is submitting a supplemental Development Operations Coordination 

Document (DOCD) for Mississippi Canyon (MC) Block 934. Shell’s Initial DOCD for the MC 935 

Unit (including MC 890, 891, 934, and 935) was approved by the Minerals Management Service 

(MMS, now Bureau of Ocean Energy Management [BOEM]) on July 1, 1998 (Plan Control 

No. N-6234). Shell submitted a Supplemental DOCD on March 23, 2010 (Plan Control 

No. S-7405) with revisions to the DOCD submitted February 14, 2011 and November 20, 2012. 

Under this DOCD, Shell plans to drill, complete, and produce from two subsea wells, A10 and 

back-up well A11. The surface locations are in MC 934. New wellheads, trees, and jumpers and 

flying leads, will be installed to facilitate production from the new wells to an existing Europa 

manifold located in MC 934. Production will then be transported 18 miles (29 km) through the 

existing flowline system to the existing Mars A tension leg platform (TLP) in MC 807. 

Only drilling, completion, and subsea tie back activities are included in this DOCD. The new 

wells will be controlled from the Mars TLP through a step-out of existing Europa umbilicals. No 

expansion of the existing Mars TLP is anticipated as a result of the addition of these wells. There 

will be minor control system modifications to accommodate the new wells within the existing 

Europa control scheme. Non-anchored vessels will be used for jumper and flying lead 

installation. 

The lease area is 61 miles (98 km) from the nearest shoreline, 101 miles (163 km) from the 

onshore support base at Port Fourchon, Louisiana, and 88 miles (142 km) from the helicopter 

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

miles. Water depth at the wellsites is approximately 3,853 ft (1,174 m). 

The Atwood Condor or a similar dynamically positioned semisubmersible rig will be used for 

drilling. Drilling of the wells is expected to commence during the first quarter of 2014 and 2015. 

The average time to drill and complete a well will be approximately 133 days. 

Purpose of the EIA 

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

(OCSLA), 43 U.S.C. §§ 1331-1356, as well as regulations including 30 CFR 550.242(s) and 550.261. 

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

October 1, 2011, the Bureau of Ocean Energy Management, Regulation and Enforcement 

(BOEMRE) reorganized into two separate agencies: 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 Notices to Lessees and Operators (NTLs) issued by the former 

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. 

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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 DOCD. The EIA also analyzes the potential environmental impacts of 

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

The MMS, BOEMRE, and BOEM have 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 Statements (EIS) for the 

OCS Oil and Gas Leasing Program (MMS, 2007a; BOEM, 2012a) and in multi-lease-sale EISs for 

the Western and Central Gulf of Mexico Planning Areas (MMS, 2007b, 2008; BOEM, 2012b). The 

analyses from these documents are incorporated here by reference. Updated environmental 

baseline information relative to the Macondo incident presented in the Final Supplemental EIS 

for Central Planning Lease Sale 216/222 (BOEM, 2012c) and the Final Supplemental EIS for 

Western Planning Area Lease Sale 218 (Bureau of Ocean Energy Management, Regulation and 

Enforcement [BOEMRE], 2011) has also been incorporated. 

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 DOCD and ensure that oil and gas exploration and development activities are 

performed in an environmentally sound manner, with minimal impacts on the environment. 

Shell has incorporated these comprehensive environmental analyses by reference and built on 

them with project- and site-specific analyses, where applicable. 

OCS Regulatory Framework 

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

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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. 

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 (see DOCD Section 7). The 

OSRP demonstrates Shell’s capabilities to rapidly and effectively manage oil spills that may 

result from drilling operations. Despite the extremely low likelihood of a large oil spill occurring 

during the project, Shell has designed its response program based upon a regional capability of 

responding to a range of spill volumes that increase from small operational spills to a WCD from 

a well blowout. Shell’s program is intended to meet the response planning requirements of the 

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

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

risks, and local environmental sensitivities. The OSRP presents specific information on the 

response program that includes a description of personnel and equipment mobilization, the 

incident management team organization, and the strategies and tactics used to implement 

effective and sustained spill containment and recovery operations. 

EIA Organization 

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

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

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

Section C (Impact Analysis). 

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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 worst case discharge (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.

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A. Impact-Producing Factors 

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

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

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

effect, an analysis is provided in Section C. Potential IPFs for the proposed activity are listed 

below and briefly discussed in the following subsections: 

Drilling rig presence (including noise and lights); 

Physical disturbance to the seafloor; 

Air pollutant emissions; 

Effluent discharges; 

Water intake; 

Onshore waste disposal; 

Marine debris; 

Support vessel and helicopter traffic; and 

Accidents. 

A.1 Drilling Rig Presence (including noise and lights) 

The wells will be drilled using the Atwood Condor or a similar dynamically positioned 

semisubmersible rig. The rig will be on site for an estimated 133 days per well. Non-anchored 

vessels will be on site for jumper and flying lead installation for brief intervals. 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 Atwood Condor 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). The intensity, or 

sound pressure level, of drilling noise from DP semisubmersibles has been estimated, at the 

source, at approximately 154 dB re 1 μPa @ 1 m (Richardson et al., 1995, citing Greene, 1986; 

Evans and Nice, 1996; Nedwell and Howell, 2004). Thruster use on DP vessels can produce 

intermittent or continuous noise at levels exceeding 120 dB re 1 μPa. DP thruster noise, 

however, is variable and dependent on thruster type, operating efficiency, ship size, engine 

load, duty cycle, and weather/current conditions. 

Drilling rigs also maintain exterior lighting for working at night and navigational and aviation 

safety in accordance with applicable federal regulations. 

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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)

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Table 2 Footnotes and Applicability: 

(1) Activities that may affect a marine sanctuary or topographic feature. Specifically, if the well, platform site, or 

any anchors will be on the seafloor within the following: 

(a) 4-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 lease block. 

(2) Activities with any bottom disturbance within an OCS lease block protected through the Live Bottom 

(Pinnacle Trend) Stipulation attached to an OCS lease. 

 The Live Bottom (Pinnacle Trend) Stipulation is not applicable to the lease area. 

(3) Activities within any Eastern Gulf OCS block 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, seafloor disturbances due to anchoring will not occur. 

(5) Exploration or production activities where H2S concentrations greater than 500 ppm might be encountered. 

 DOCD 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 geohazards and archaeological assessments indicate multiple sonar contacts 

in the lease area, but none are interpreted to be historic shipwrecks. 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, seafloor disturbances due to anchoring will not 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. 

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A.2 Physical Disturbance to the Seafloor 

Semisubmersible rigs like the Atwood Condor 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. 

Non-anchored vessels will be used for jumper and flying lead installation. There will be no 

anchoring impacts, but placement of the subsea equipment on the seafloor will directly disturb 

a small area of seafloor estimated to be less than 1 ac (0.4 ha). Jumpers will be installed within 

MC 934 to link the A10 and A11 wells to the existing Europa manifold in MC 934. 

A.3 Air Pollutant Emissions 

Estimates of air pollutant emissions are provided in DOCD 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. 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 DOCD 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 from the semisubmersible rig are summarized in DOCD Section 7. Support 

vessel discharges are expected to 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 DOCD Section 7. 

Well treatment fluids, completion fluids, and workover fluids may be discharged overboard via a 

downpipe below the water surface, after treatment that complies with NPDES permit limitations 

for these fluids. Other effluent discharges expected to be 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. 

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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 

(DOCD Table 7a).

Section 316(b) of the Clean Water Act requires NPDES permits to ensure that the location, 

design, construction, and capacity of cooling water intake structures reflect the best technology 

available to minimize adverse environmental impact from impingement and entrainment of 

aquatic organisms. The current general NPDES Permit No. GMG290000 specifies requirements 

for new facilities for which construction was 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 Atwood Condor meets the 

applicability criteria for a “new, non-fixed” facility as defined by the NPDES permit and therefore 

is subject to the cooling water intake permit requirements. Affected water intakes are expected 

to be in compliance with the design, monitoring, and recordkeeping requirements of the 

NPDES permit. 

A.6 Onshore Waste Disposal 

Wastes generated during development activities are tabulated in DOCD Section 7. 

Non-hazardous trash and debris and non-recyclable waste will be transported to Newpark 

Environmental in Ingleside, Texas or Bridge City, Texas. Recyclable trash and debris will be 

recycled at Omega Waste Management in 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. in Denton, Texas. Used oil will be sent to Omega Waste 

Management in Patterson, Louisiana, or ARC of New Iberia, Louisiana for recycling. 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. 

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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 

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: 

a small fuel spill, which is the most likely type of spill during OCS development activities; and 

an oil spill resulting from an uncontrolled blowout. A blowout resulting in a large oil spill is an 

extremely rare event, and the probability of such an event will be minimized by Shell’s well 

control and blowout prevention measures detailed in DOCD 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. 

Previous lease sale EISs (MMS, 2007b; BOEMRE, 2011; BOEM, 2012a,c) analyzed other types of 

accidents including: chemical spills, vessel collisions, and loss of well control. These accidents 

are discussed briefly in Section A.9.4. 

A.9.2 Small Fuel Spill 

Spill Size. According to the analysis in BOEM (2012b), the most likely type of small spill 

(<1,000 barrels [bbl]) as a result of OCS activities is a minor diesel fuel spill. Historically, most 

diesel spills have been <1 bbl, and this size is predicted to be the most common in ongoing and 

future OCS activities in the Western and Central Gulf of Mexico Planning Areas (BOEM, 2012b). 

The median size for spills <1 bbl is <0.024 bbl, and the median size for spills of 1 to 10 bbl is 3 bbl 

(BOEM, 2012b). For this analysis, a small diesel fuel spill of 3 bbl is assumed. Operational 

experience suggests that the most likely cause of such a spill would be a hose rupture resulting 

in the loss of the contents of a fuel transfer hose, which is less than 3 bbl. 

Spill Fate. The fate of a small fuel spill in the lease area would depend on meteorological and 

oceanographic conditions at the time, as well as the effectiveness of spill response activities. 

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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). 

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 is 

61 miles (98 km) from the nearest shoreline (Louisiana). Modeling results discussed below 

indicate that a spill in the lease area would have a 4% probability of contacting the nearest 

Louisiana shoreline (Plaquemines Parish) within 10 days after a spill. 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 outer continental shelf 

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. DOCD Section 9b provides a detailed discussion of 

Shell’s response to a spill.

A.9.3 Large Oil Spill 

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 DOCD 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 DOCD using the requirements prescribed by 

NTL 2010-N06. The WCD is 207,700 bbl for the first day with a 30-day average of 

134,011 barrels of oil per day (BOPD). The detailed analysis of this calculation can be found in 

DOCD Section 2j. The WCD scenario for this DOCD, 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. 

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Shell has a robust system in place to prevent blowouts. Included in DOCD Sections 2j and 9b is 

Shell’s response to NTL 2010-N06, which includes descriptions of measures to prevent a 

blowout, reduce the likelihood of a blowout, and conduct effective and early intervention in the 

event of a blowout. Shell will also comply with NTL 2010-N10 and the Final Drilling Safety Rule, 

which specify additional safety measures for OCS activities. 

Spill Trajectory. The fate of a large oil spill in the lease area would depend on meteorological 

and oceanographic conditions at the time. The Oil Spill Risk Analysis (OSRA) model is a 

computer simulation of oil spill transport that uses realistic data for winds and currents to 

predict spill fate. The OSRA report by Ji et al. (2004) provides conditional contact probabilities 

for shoreline segments. 

The results for Launch Area 58 (the launch area nearest to the lease area) are presented in 

Table 3. The model predicts no shoreline contacts within 3 days. After 10 days, three Louisiana 

parishes may be contacted. After 30 days, 11 counties and parishes from Texas to the Florida 

Panhandle may be contacted. Plaquemines Parish, Louisiana, has the greatest probability of 

shoreline contact, with a 4% and 8% chance within 10 and 30 days, respectively. 

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 and State Conditional Probability of Contacta

(%)

3 Days 10 Days 30 Days

C10 Galveston, TX -- -- 1

C12 Jefferson, TX -- -- 1

C13 Cameron, LA -- -- 3

C14 Vermilion, LA -- -- 2

C15 Iberia, LA -- -- 1

C17 Terrebonne, LA -- 1 3

C18 Lafourche, LA -- 2 3

C19 Jefferson, LA -- -- 1

C20 Plaquemines, LA -- 4 8

C21 St. Bernard, LA -- -- 1

C28 Okaloosa, FL -- -- 1

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 

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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 

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 DOCD Section 9b for a detailed description of spill response measures. 

A.9.4 Other Accidents Not Analyzed in Detail 

MMS (2007b), BOEMRE (2011), and BOEM (2012a,c) discussed other types of accidents 

including: 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 DOCD. 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 

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chemicals used in drilling fluids, the following chemicals are likely to be used on the rig: ethylene 

glycol (blowout prevention control fluid, used in closed cooling loops for crane and main engines 

and brake coolers), cement (used to cement casing in place), solvents (used in painting 

operations), hydraulic fluids (used in cranes and other hydraulic rig equipment), lubricating oil 

and grease (used in reciprocating and electrical equipment), and sodium hypochlorite (dilute, 

used as laundry bleach and disinfectant). 

A study of environmental risks of chemical products used in OCS activities determined that only 

two chemicals could potentially affect the marine environment in the concentrations typically 

used: zinc bromide and ammonium chloride (Boehm et al., 2001). The project addressed by this 

DOCD 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 DOCD 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 DOCD Sections 2j and 9b for further information. 

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

B. Affected Environment 

The lease area is in the north-central Gulf of Mexico, 61 miles (98 km) from the nearest 

shoreline, 101 miles (163 km) from the onshore support base at Port Fourchon, Louisiana, and 

88 miles (142 km) from the helicopter base at Boothville, Louisiana. 

Water depth in MC 934 at the proposed A10 and A11 wellsites is approximately 3,853 ft 

(1,174 m) and there is no evidence of seafloor or near-surface faulting, slumping, amplitudes, or 

fluid expulsion features within 12,000 ft (3,658 m) of both wellsites (Fugro McClelland, 1990; 

C&C Technologies, Inc., 2012). The side-scan sonar survey identified 36 sonar contacts within 

2,000 ft (610 m) of A10 and A11. Five contacts are listed as marine avoidance zones, and 30 as 

simple debris or possibly barrels that are not archaeologically significant. Shell’s procedure 

“Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area,” which has been 

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previously approved by MMS and BOEM[1] 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 activities. 

A detailed description of the regional affected environment is provided in previous 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. Updated environmental baseline information relative to the Macondo incident 

presented in the Final Supplemental EIS for Central Planning Lease Sale 216/222 (BOEM, 2012c) 

has also been incorporated. 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 lease sale EISs (MMS, 2007b; 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 and Central 

Gulf of Mexico Planning Areas (MMS, 2001, 2007b, 2008), the final EIS for the Western and 

Central Gulf of Mexico Planning Areas (BOEM, 2012b), and the Final Programmatic EIS for the 

OCS Oil and Gas Leasing Program: 2012-2017 (BOEM, 2012a). 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 December 14, 2012, Louisiana, Mississippi, and Alabama coastal counties 

 

[1] MMS approval of West Boreas Supplemental Exploration Plan, MS 5231 December 16, 2008, Control No. S-07273, Mississippi Canyon Area 

Block 762, Lease OCS-G 07957; Mississippi Canyon Area Block 806, Lease OCS-G 07962 and BOEM approval of the Supplement to the 

Conceptual Deepwater Operations Plan for Mars B project, August 12, 2010, MS 5220. 

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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. One coastal 

metropolitan area in Florida (Tampa) is a nonattainment area for lead 2008 Standard. 

Winds in the region are driven by the clockwise circulation around the Bermuda High 

(MMS, 2007b). The Gulf of Mexico is located to the southwest of this center of circulation, 

resulting in a prevailing southeasterly to southerly flow, which is conducive to transporting 

emissions toward shore. However, circulation is also affected by tropical cyclones (hurricanes) 

during summer and fall and by extratropical cyclones (cold fronts) during winter. 

IPFs potentially affecting air quality are air pollutant emissions and two types of accidents: 

a small fuel spill and a large oil spill. 

Impacts of Air Pollutant Emissions 

Air pollutant emissions are the only routine IPF likely to affect air quality. Offshore air pollutant 

emissions will result from the operation of the drilling rig 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 DOCD 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 DOCD is therefore exempt from 

further air quality review pursuant to 30 CFR 550.303(d). 

The Breton Wilderness Area, which is part of the Breton National Wildlife Refuge (NWR), is 

designated under the Clean Air Act as a Prevention of Significant Deterioration (PSD) Class I air 

quality area. The BOEM coordinates with the National Park Service (NPS) and the USFWS if 

emissions from proposed projects may affect the Breton Class I area. The lease area is 

approximately 100 miles (161 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 previous EISs (MMS, 2007b; BOEM, 2012b,c). 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. DOCD 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. 

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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; BOEM, 2012b,c).

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 (61 miles [98 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 (BOEM, 2012c). 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 are expected to 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 EISs (BOEM, 2012b,c).

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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 are 

expected to be met and little or no impact on water quality is anticipated. 

Deck drainage includes effluents resulting from rain, deck washings, and runoff from curbs, 

gutters, and drains, including drip pans in work areas. Rainwater that falls on uncontaminated 

areas of the drilling rig will flow overboard without treatment. However, rainwater that falls on 

the drilling rig deck and other areas such as chemical storage areas and places where equipment 

is exposed will be collected and oil and water separated to meet NPDES permit requirements. 

Negligible impact on water quality is anticipated. 

Other discharges from the semisubmersible rig expected to be in accordance with the NPDES 

permit, such as desalination unit brine and uncontaminated cooling water, fire water, and 

ballast water, are expected to be diluted rapidly and have little or no impact on water quality. 

Support vessels will discharge treated sanitary and domestic wastes. These will have a slight 

effect on water quality in the immediate vicinity of the discharges. Support vessel discharges 

are subject to USCG regulations and, as applicable, the NPDES Vessel General Permit, and 

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

Impacts of a Small Fuel Spill 

Potential impacts of a small spill on water quality are expected to be consistent with those 

analyzed and discussed in recent EISs (MMS, 2007b; BOEM, 2012b,c). 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. DOCD 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).

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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; BOEM, 2012b,c). 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, 2012c).

Once oil enters the ocean, a variety of physical, chemical, and biological processes act to 

disperse the oil slick. These processes include spreading, evaporation of the more volatile 

constituents, dissolution into the water column, emulsification of small droplets, agglomeration 

sinking, microbial modification, photochemical modification, and biological ingestion and 

excretion (NRC, 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 (61 miles [98 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 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD Section 9b provides detail on spill response measures. 

Therefore, no significant spill impacts on water quality are expected. 

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C.2 Seafloor Habitats and Biota 

Water depth at the proposed well surface locations is approximately 3,853 ft (1,174 m). See 

DOCD Section 6a for further information. 

According to the BOEM (2012a), existing information for the deepwater Gulf of Mexico indicates 

that the seafloor is composed primarily of soft sediments; hard bottom communities are rare. 

MC 934 is 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 (53% [MT-3]; 45.5% [MT-4]) and silt (42% [MT-3]; 

45.5% [MT-4]). 

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). 

Statio

n

Location 

Relative to 

Lease Area

Water 

Depth 

(m)

Abundance

Meiofauna

(individuals/m2

)

Macroinfauna

(individuals/m2

)

Megafauna

(individuals/ha)

MT3 15 mi NNE 987 885,995 4,924 1,034

MT4 21 mi SE 1,401 246,058 3,262 1,548

Meiofaunal and megafaunal abundance from Rowe and Kennicutt (2009); macroinfaunal abundance from Wei (2006). 

Meiofauna (animals passing through a 0.5-mm sieve but retained on a 0.062-mm sieve) 

densities in water depths representative of the lease area typically range from about 

250,000 to 650,000 individuals/m2 (Rowe and Kennicutt, 2009). Nematodes, nauplii, and 

harpacticoid copepods were the three dominant groups in the meiofauna, accounting for about 

90% of total abundance. 

The benthic macroinfauna is characterized by small mean individual sizes and low densities, 

both of which are a reflection of the meager primary production in Gulf of Mexico surface 

waters (Wei, 2006). Densities decrease exponentially with water depth. Based on an equation 

presented by Wei (2006), macroinfaunal densities in the water depth of the wellsites are 

expected to be about 2,800 individuals/m2, or 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 were the polychaetes Litocorsa antennata, Aricidea suecica, Tharyx marioni, and 

Paralacydonia paradoxa and the bivalve Heterodonta sp. 

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Megafaunal density from nearby stations MT-3 and MT-4 was 1,034 and 1,548 individuals/ha, 

respectively (Table 4). Densities of 300 to 2,000 individuals/ha were reported from other 

stations in a similar depth range. Common megafauna included motile groups such as 

decapods, ophiuroids, holothurians, and demersal fishes, as well as sessile groups such as 

sponges and anemones. 

Bacteria are 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 inches (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 

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 

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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 two surface locations in this development-drilling 

program, the total impact area would be 388 ac (157 ha). In light of the proximity of the 

proposed wells to each other, the overall impact area could be reduced. Soft bottom 

communities are ubiquitous along the northern Gulf of Mexico continental slope (Gallaway, 

1988; Gallaway et al., 2003; Rowe and Kennicutt, 2009). Impacts from drilling discharges during 

this project will have no significant impact on soft bottom benthic communities on a regional 

basis. 

Impacts of a Large Oil Spill 

The most likely effects of a subsea blowout on benthic communities would be within a few 

hundred meters of the wellsites. The MMS (2007b) estimates that a severe subsurface blowout 

could resuspend and disperse sediments within a 984-ft (300-m) radius. While coarse sediments 

(sands) would probably settle at a rapid rate within 1,312 ft (400 m) from the blowout site, fine 

sediments (silts and clays) could be resuspended for more than 30 days and dispersed over a 

much wider area. 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD Section 9b provides detail on spill response measures. 

Therefore, no significant spill impacts on soft bottom communities are expected. 

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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 28 miles (45 km) west of the lease area in MC 969 (Brooks et al., 2009). 

The chemosynthetic community assessment by Fugro McClelland (1990) and C&C Technologies, 

Inc. (2012) 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. 

Impacts of Effluent Discharges 

The chemosynthetic community assessment included in this DOCD, based on the reports by 

Fugro McClelland (1990) and C&C Technologies, Inc. (2012), 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, it is unlikely that significant impacts to 

these communities would occur because of the distance from the discharge location. 

Impacts of a Large Oil Spill 

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect 

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical 

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill 

location. However, during the Macondo spill, subsurface plumes were reported at a water 

depth of about 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 

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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 

Fugro McClelland (1990) and C&C Technologies, Inc. (2012) 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, 2012c).

The potential for a spill to affect deepwater corals was observed during an October 2010 survey 

of deepwater coral habitats in water depths of 4,600 ft (1,400 m) approximately 7 miles (11 km) 

southwest of the Macondo wellhead. Much of the soft coral observed in a location measuring 

about 50 by 130 ft (15 by 40 m) was covered by a brown flocculent material (BOEMRE, 2010) 

with signs of stress, including varying degrees of tissue loss and excess mucous production 

(White et al., 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 75 miles (120 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 lease 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 

MC 316, located 41 miles (66 km) north of the lease area. 

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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 104 miles (167 km) 

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 

seagrass communities and low-relief hardbottom reef within the Gulf of Mexico Eastern 

Planning Area leases in water depths of 328 ft (100 m) or less and portions of Pensacola and 

Destin Dome Area Blocks in the Central Planning Area. The nearest blocks covered by the live 

bottom stipulation, as defined by NTL 2009-G39, are about 140 miles (226 km) northeast of the 

project area in Destin Dome 573. 

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. 

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. 

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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, Eb X X None

Green turtle Chelonia mydas T, Ec X X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempii E X X None

Birds

Piping Plover Charadrius melodus T -- X

Coastal Texas, 

Louisiana, Mississippi, 

Alabama, and Florida 

(Panhandle)

Whooping Crane Grus americana E -- X

Coastal Texas 

(Aransas National 

Wildlife Refuge)

Fishes

Gulf sturgeon Acipenser oxyrinchus desotoi T -- X

Coastal Louisiana, 

Mississippi, Alabama, 

and Florida (Panhandle)

Terrestrial Mammals

Beach mouse (Alabama, 

Choctawhatchee, 

Perdido Key, St. Andrew)

Peromyscus polionotus E -- X

Alabama and Florida 

(Panhandle) beaches

Abbreviations: E = Endangered; T = Threatened. 

a

 The blue, fin, humpback, North Atlantic right, and sei whales are rare or extralimital in the Gulf of Mexico and are 

unlikely to be present in the lease area. 

b

 The loggerhead turtle is 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. 

Coastal endangered or threatened species include the Florida manatee, Piping Plover, 

Whooping Crane, Gulf sturgeon, and four subspecies of beach mouse. Critical habitat has been 

designated for all of these species as indicated in Table 5 and discussed in individual sections. 

Two other coastal species (Bald Eagle and Brown Pelican) discussed by MMS (2007b) 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 

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(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 

(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). A review of sighting reports from seismic mitigation surveys in the 

Gulf of Mexico conducted over a 6-year period found a mean group size for sperm whales of 

2.5 individuals (Barkaszi et al., 2012). In these mitigation surveys, sperm whales were the most 

common cetacean encountered (Barkaszi et al, 2012). 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). 

Current threats to sperm whale populations worldwide are discussed in a final recovery plan for 

the sperm whale recently published by NOAA (NMFS, 2010a). Threats are defined as “any factor 

that could represent an impediment to recovery,” and include fisheries interactions, 

anthropogenic noise, vessel interactions, contaminants and pollutants, disease, injury from 

marine debris, research, predation and natural mortality, direct harvest, competition for 

resources, loss of prey base due to climate change and ecosystem change, and cable laying. 

In the Gulf of Mexico, the impacts from many of these threats are identified as either low or 

unknown (BOEMRE, 2011; BOEM, 2012c). 

IPFs 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. 

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Impacts of Drilling Rig Presence, Noise, and Lights 

Noise from routine drilling activities may be audible to sperm whales and therefore has the 

potential to disturb individuals near the lease area. As discussed in Section A.1, the bandwidth 

of sounds generated by the drilling rig is approximately 100 to 500 Hz. 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, duration, 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; BOEM, 2012a,b,c) 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 

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 

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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 previous 

EISs (MMS, 2007b; BOEM, 2012a,b,c) 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 DOCD 

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. DOCD 

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 (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. 

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Impacts of a Large Oil Spill 

Potential spill impacts on marine mammals including sperm whales are discussed in previous 

EISs (MMS, 2007b; BOEM, 2012a,b,c) and by the NMFS (2007). Oil impacts on marine mammals 

are discussed by Geraci and St. Aubin (1990). For this DOCD, 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. 

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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 61 miles (98 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 

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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,c). This mitigation measure 

will minimize the potential for disturbing manatees, and no significant impacts are expected. 

Impacts of a Large Oil Spill 

The OSRA results summarized in Table 3 predict that some Texas, Louisiana, and Florida 

shorelines could be contacted by a spill within 30 days. There is no critical habitat designated in 

these areas, and the number of manatees potentially present is a small fraction of the 

population in peninsular Florida. 

In the event that manatees were exposed to oil, effects could include direct impacts from oil 

exposure, as well as indirect impacts due to response activities and materials (e.g., vessel traffic, 

noise, and dispersants) (MMC, 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. 

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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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 previous EISs (MMS, 2007b; BOEM, 

2012a,b,c) 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 DOCD Section 6h). All marine mammals are protected species 

under the MMPA. The most common non-endangered cetaceans in the deepwater 

environment are odontocetes such as the pantropical spotted dolphin, spinner dolphin, and 

Clymene dolphin. A brief summary is presented 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: the Bryde’s whale (Balaenoptera edeni) and minke whale 

(Balaenoptera acutorostrata). The Bryde’s whale (Balaenoptera edeni) has been sighted most 

frequently along the 328-ft (100-m) isobath (Davis and Fargion, 1996; Davis et al., 2000). Most 

sightings have been made in the DeSoto Canyon region and off western Florida, although there 

have been some in the west-central portion of the northeastern Gulf. The minke whale is 

considered rare in the Gulf of Mexico, with the only confirmed records coming from strandings 

(Würsig et al., 2000). Based on the available data, it is possible that Bryde’s whales could occur 

in the lease area. 

Dwarf and pygmy sperm whales. At sea, it is difficult to differentiate dwarf sperm whales 

(Kogia sima) from pygmy sperm whales (Kogia breviceps), and sightings are often grouped 

together as “Kogia spp.” Both species have a worldwide distribution in temperate to tropical 

waters. In the Gulf of Mexico, both species occur primarily along the continental shelf edge and 

in deeper waters off the continental shelf (Mullin et al., 1991; Mullin, 2007; Waring et al., 2012). 

Either species could occur in the lease area. 

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Beaked whales. Four species of beaked whales are known from the Gulf of Mexico. They are 

Blainville’s beaked whale (Mesoplodon densirostris), Cuvier’s beaked whale (Ziphius cavirostris), 

Sowerby’s beaked whale (Mesoplodon bidens), and Gervais’ beaked whale (Mesoplodon 

europaeus). Stranding records in the Gulf of Mexico suggest that Gervais’ beaked whale is the 

most common and Sowerby’s beaked whale is extralimital. Due to the difficulties of at-sea 

identification, beaked whales in the Gulf of Mexico are identified either as Cuvier’s beaked 

whales or are grouped into an undifferentiated complex (Mesoplodon spp. and Ziphius spp.). 

In the northern Gulf of Mexico, they are broadly distributed in waters greater than 3,281 ft 

(1,000 m) over lower slope and abyssal landscapes (Davis et al., 2000). Any of these species 

could occur in the lease area (Waring et al., 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). 

Bottlenose dolphin populations in the northern Gulf of Mexico are separated into 

37 geographically distinct population units, or stocks, for management purposes by the NMFS 

(Waring et al., 2012). NMFS (2013) has proposed to classify the Gulf of Mexico Northern Coastal 

Stock, Western Coastal Stock, and all 32 of the Bay, Sound, and Estuarine Stocks as strategic 

stocks based primarily on the occurrence of an “unusual mortality event” of unprecedented size 

and duration that has affected these stock areas. This unusual mortality event began in 

February 2010 and is ongoing. Carmichael et al. (2012) hypothesized that the unusual number 

of bottlenose dolphin strandings in the northern Gulf of Mexico during this time may have been 

associated with environmental perturbations, including sustained cold weather and the 

Macondo spill in 2010 as well as large volumes of cold freshwater discharge in the early months 

of 2011. 

IPFs 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. 

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 

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similar sources. Due to the limited scope, duration, 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; BOEM, 2012a,b,c). Therefore, no significant impacts are expected. 

Impacts of Support Vessel and Helicopter Traffic 

Support vessel traffic has the potential to disturb marine mammals, and there is also a risk of 

vessel strikes. Data concerning the frequency of vessel strikes are presented in the lease sale 

EIS (MMS, 2007b). To reduce the potential for vessel strikes, the BOEM and BSEE have issued 

NTL 2012-JOINT-G01, which recommends protected species identification training and that 

vessel operators and crews maintain a vigilant watch for marine mammals and slow down or 

stop their vessel to avoid striking protected species, and requires operators to report sightings 

of any injured or dead protected species. Vessel operators and crews are required to attempt to 

maintain a distance of 300 ft (91 m) or greater when whales are sighted and 150 ft (45 m) when 

small cetaceans are sighted. When cetaceans are sighted while a vessel is underway, vessels 

must attempt to remain parallel to the animal’s course and avoid excessive speed or abrupt 

changes in direction until the cetacean has left the area. Vessel operators are required to 

reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large assemblages of 

cetaceans are observed near an underway vessel, when safety permits. Compliance with this 

NTL will minimize the likelihood of vessel strikes as well as reduce the chance for disturbing 

marine mammals, and therefore no significant impacts are expected. 

Aircraft traffic also has the potential to disturb marine mammals (Würsig et al., 1998). However, 

while flying offshore, helicopters maintain altitudes above 700 ft (213 m) during transit to and 

from the working area. In addition, guidelines and regulations specify that helicopters maintain 

an altitude of 1,000 ft (305 m) within 300 ft (91 m) of marine mammals (BOEM, 2012a,b,c). This 

altitude will minimize the potential for disturbing marine mammals, and no significant impacts 

are expected (BOEM, 2012a,b,c).

Impacts of a Small Fuel Spill 

Potential spill impacts on marine mammals are discussed in previous EISs (MMS, 2007b; 

BOEM, 2012a,b,c), and oil impacts on marine mammals in general are discussed by Geraci and 

St. Aubin (1990). For this DOCD, there are no unique site-specific issues with respect to spill 

impacts on these animals. 

The probability of a fuel spill will be minimized by Shell’s preventative measures during fuel 

transfer. In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate 

and reduce the potential for impacts on marine mammals. DOCD 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 

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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 previous EISs (MMS, 2007b; BOEM, 

2012a,b,c) and by Geraci and St. Aubin (1990). For this DOCD, 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 DOCD Section 2j. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the impacts. DOCD Section 9b provides detail on spill 

response measures. Therefore, no significant spill impacts on marine mammals are expected. 

C.3.5 Sea Turtles (Endangered/Threatened) 

As listed in DOCD 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 

(BOEM, 2012a).

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Leatherbacks and loggerheads are the most likely species to be present near the lease area as 

adults. Green, hawksbill, and Kemp’s ridley turtles are typically inner shelf and nearshore 

species, unlikely to occur near the lease area as adults. Hatchlings or juveniles of any of the sea 

turtles may be present in deepwater areas, including the lease area, where they may be 

associated with Sargassum and other flotsam. 

All five sea turtle species in the Gulf of Mexico are migratory and use different marine habitats 

according to their life stage. These habitats include high-energy beaches for nesting females 

and emerging hatchlings and pelagic convergence zones for hatchling and juvenile turtles. 

As adults, green, hawksbill, and loggerhead turtles forage primarily in shallow, benthic habitats. 

Leatherbacks are the most pelagic of the sea turtles, feeding primarily on jellyfish. 

Sea turtle nesting in the northern Gulf of Mexico can be summarized by species as follows: 

Loggerhead turtles – Loggerheads nest in significant numbers along the Florida Panhandle and, 

to a lesser extent, from Texas through Alabama (MMS, 2007b). The nearest significant 

nesting area of loggerhead turtles is found in Louisiana, on beaches within the Breton NWR; 

Green and leatherback turtles – Green and leatherback turtles infrequently nest on Florida 

Panhandle beaches (Florida Fish and Wildlife Conservation Commission, 2011); 

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 

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 

(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, duration, 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). 

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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; BOEM, 

2012a,b,c) 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 DOCD, 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. DOCD 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 (MMS, 2007b; BOEM, 2012a,b,c). 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. 

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A small fuel spill in the lease area would be unlikely to affect sea turtle nesting beaches because 

the lease area is 61 miles (98 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. DOCD 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. This area has a 

contact probability 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). 

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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

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and reduce the impacts. DOCD 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 69 miles (112 km) from the nearest shoreline inhabited by Piping Plovers. The 

OSRA results summarized in Table 3 predict that Texas, Louisiana, and Florida shorelines 

designated as critical habitat for the wintering Piping Plover could be contacted by a spill within 

30 days. Plaquemines Parish, Louisiana, which has the highest probability of contact for the 

10-day 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 [WCEP], 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, 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 427 miles (687 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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; 

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 

DOCD, there are no unique site-specific issues with respect to this species. 

The lease area is about 127 miles (205 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 

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 

DOCD 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. 

DOCD 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; 

BOEM, 2012b,c). For this DOCD, there are no unique site-specific issues with respect to these 

species. 

The lease area is about 175 miles (281 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 seabirds and 

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; BOEM, 

2012a,b,c). For this DOCD, 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. 

DOCD 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; 

BOEM, 2012b). For this DOCD, 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD Section 9b provides detail on spill response measures. 

Therefore, no significant spill impacts on marine and pelagic birds are expected. 

C.4.2 Shorebirds and Coastal Nesting Birds 

Threatened and endangered bird species (Piping Plover and Whooping Crane) are discussed in 

Section C.3. Various species of non-endangered birds are also found along the northern 

Gulf Coast, including diving birds, shorebirds, marsh birds, wading birds, and waterfowl. 

Gulf Coast marshes and beaches also provide important feeding grounds and nesting habitats. 

Species that breed on beaches, flats, dunes, bars, barrier islands, and similar habitats include the 

Sandwich Tern, Wilson’s Plover, Black Skimmer, Forster’s Tern, Gull-Billed Tern, Laughing Gull, 

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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 remains endangered on the Louisiana list of Endangered 

Species (State of Louisiana Department of Wildlife and Fisheries, 2013), is listed as a species of 

greatest conservation need by the State of Mississippi (Mississippi Department of Wildlife, 

Fisheries and Parks, 2005) and 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, duration, 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, Louisiana, and Florida 

that include habitat for shorebirds and coastal nesting birds could be affected within 30 days. 

Studies being performed after the Macondo spill provide 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. 

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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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. 

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 

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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 are expected to 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 

(DOCD Table 7a). Section 316(b) of the Clean Water Act requires NPDES permits to ensure that 

the location, design, construction, and capacity of cooling water intake structures reflect the 

best technology available to minimize adverse environmental impact from impingement and 

entrainment of aquatic organisms. The current general NPDES Permit No. GMG290000 specifies 

requirements for new facilities for which construction was 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 Atwood Condor meets 

the applicability criteria for a “new, non-fixed” facility as defined by the NPDES permit and 

therefore is subject to the cooling water intake permit requirements. Affected water intakes are 

expected to be in compliance with the design, monitoring, and recordkeeping requirements of 

the NPDES permit. 

Impacts of a Small Fuel Spill 

Potential spill impacts on fisheries resources are discussed in recent EISs (MMS, 2007b; 

BOEM, 2012a,b). For this DOCD, 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. DOCD 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 

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600 ft (183 m). The shelf edge is the outer boundary for coastal migratory pelagic fishes, reef 

fishes, and shrimps. EFH for corals and coral reefs includes some shelf-edge topographic 

features on the Texas-Louisiana OCS, the nearest of which is located 42 miles (68 km) north 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): 

Atlantic bluefin tuna (spawn, eggs, 

larvae) 

Skipjack tuna (spawn) 

Yellowfin tuna (all) 

Swordfish (all) 

Blue marlin (juveniles, adults) 

White marlin (juveniles) 

Whale shark (all) 

Longfin mako shark (all) 

Oceanic whitetip shark (all) 

Atlantic yellowfin tuna (all) 

Bigeye thresher 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 129 miles (207 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. 

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, 

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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, duration, and 

geographic extent of drilling activities, any short-term impacts on EFH for highly migratory 

pelagic fishes are not expected to be biologically significant. 

Impacts of a Small Fuel Spill 

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b; BOEM, 2012a,b). For 

this DOCD, there are no unique site-specific issues with respect to spill impacts. 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations including fuel transfer. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the potential for impacts on EFH. DOCD 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 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 42 miles (68 km) north 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; BOEM, 2012a,b). For 

this DOCD, there are no unique site-specific issues with respect to EFH. 

An oil spill in offshore waters would temporarily increase hydrocarbon concentrations on the 

water surface and potentially the subsurface as well. Given the extent of EFH designations in 

the Gulf of Mexico (GMFMC, 2005; NMFS, 2009), some impact on EFH would be unavoidable. 

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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 42 miles (68 km) north 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 934 is on the list of archaeological survey blocks (BOEM, 2012d). The archaeological surveys 

conducted by C&C Technologies, Inc. (2012) and Fugro GeoServices, Inc. (2005) detected 

unidentified sonar targets within the survey area that were classified as modern debris and are 

not recommended for investigation on the basis of archaeological potential. 

Avoidance radii of 100 ft (30 m) will be established around five marine avoidance zones 

identified near A10 and A11. An additional 31 sonar contacts, which may be dumped waste 

barrels, were deemed to be not archaeologically significant. An avoidance radius of 50 ft (15 m) 

will be observed around these contacts. 

Because there are no historic shipwreck sites in the lease area (see DOCD 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 

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summarized in Table 3 predicts that Texas, Louisiana, and Florida shorelines could be contacted 

by a spill within 30 days. 

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; BOEM 2012a), depending on its 

extent, trajectory, and persistence. 

While MMS (2007b) noted that if an oil spill contacted 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 unavoidable direct and indirect impacts could be longer term and not easily reversible 

(BOEM, 2012a,b). 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD Section 9b provides detail on spill response measures. 

C.6.2 Prehistoric Archaeological Sites 

With a water depth of approximately 3,853 ft (1,174 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 BOEM (2012a) estimates that a severe 

subsurface blowout could resuspend and disperse sediments within a 984-ft (300-m) radius. 

Along the northern Gulf Coast, prehistoric sites occur frequently along the barrier islands and 

mainland coast and along the margins of bays and bayous (MMS, 2007b). The OSRA modeling 

summarized in Table 3 predicts that Texas, Louisiana, and Florida shorelines could be contacted 

by a spill within 30 days. A spill reaching a prehistoric site along these shorelines could coat 

fragile artifacts or site features and compromise the potential for radiocarbon dating organic 

materials in a site (although other dating methods are available and it is possible to 

decontaminate an oiled sample for radiocarbon dating). If appropriate measures are not in 

place, 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). 

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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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD Section 9b provides detail on spill response measures. 

Therefore, no significant spill impacts on archaeological resources are expected. 

C.7 Coastal Habitats and Protected Areas 

Coastal habitats in the northern Gulf of Mexico that may be affected by oil and gas activities are 

described in previous EISs (MMS, 2007b; BOEM, 2012a,b,c) 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 DOCD 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 previous EISs (MMS, 2007b; BOEM, 

2012a,b,c). Coastal habitats inshore of the project area include barrier beaches and dunes, 

wetlands, and submerged seagrass beds. For this DOCD, there are no unique site-specific issues 

with respect to coastal habitats. 

The OSRA results summarized in Table 3 predict that shorelines of Texas, Louisiana, and Florida 

could be affected within 30 days. Plaquemines Parish, Louisiana has the highest probability of 

contact for the 10-day and 30-day intervals (4% and 8%, respectively). Two other Louisiana 

parishes (Terrebonne and Lafourche) may be contacted within 10 days. After 30 days, 

11 counties or parishes may be contacted from Galveston, Texas, to Okaloosa County in the 

Florida Panhandle. 

The shorelines within the geographic range predicted by the OSRA modeling include extensive 

barrier beaches and wetlands, with submerged seagrass beds occurring in sheltered areas 

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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: 

Brazoria NWR 

Galveston Island State Park 

Apffel Park 

Seawolf Park 

Old Fort Travis Park 

Atkinson Island Wildlife Management 

Area (WMA) 

Ft. Anahuac Park 

Anahuac NWR 

McFaddin NWR 

Candy Abshier WMA 

Atkinson Island WMA 

Sea Rim State Park 

Murphree WMA 

Texas Point NWR 

Sabine NWR 

Cameron Prairie NWR 

LaCassine NWR 

Little Pecan NA 

Peveto Woods NA 

Lower Neches WMA 

Rockefeller WMA and Game Preserve 

Paul J. Rainey WMA 

Marsh Island WMA 

Cypremort Point State Park 

Shell Keys NWR 

Atchafalaya Delta WMA 

Mandalay NWR 

Isles Dernieres Barrier Islands Refuge 

Pointe-aux-Chenes WMA 

Wisner State WMA 

Grand Isle State Park 

Salvador WMA 

Jean Lafitte National Historical Park and 

Preserve 

Lafitte Woods NA 

Delta NWR 

Pass-a-Loutre WMA 

Breton NWR 

St. Bernard State Park 

Biloxi WMA 

Bayou Sauvage NWR 

Gulf Islands National Seashore 

Pensacola Bay Surface Water 

Improvement and Management Area 

Choctawhatchee Bay Surface Water 

Improvement and Management Area 

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59

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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD Section 9b provides detail on spill response measures. 

Therefore, no significant spill impacts on coastal habitats are expected. 

C.8 Socioeconomic and Other Resources 

C.8.1 Recreational and Commercial Fishing 

BOEM has reexamined the analysis for recreational and commercial fishing presented in 

MMS (2007b, 2008) based on additional information and in consideration of the Macondo spill. 

No new information was found that would alter the potential impacts on commercial fishing 

(BOEMRE, 2011; BOEM, 2012c). The main commercial fishing activity in deep waters of the 

northern Gulf of Mexico is pelagic longlining for tunas, swordfishes, and other billfishes 

(Continental Shelf Associates, Inc., 2002). Pelagic longlining has occurred historically in the 

project area, primarily during spring and summer. 

It is unlikely that any commercial fishing activity other than longlining occurs at or near the 

project area. Benthic species targeted by commercial fishers occur on the upper continental 

slope, well inshore of the project area. Royal red shrimp (Pleoticus robustus) are caught by 

trawlers in water depths of about 820 to 1,804 ft (250 to 550 m). Tilefishes (primarily 

Lophalotilus chamaeleonticeps) are caught by bottom longlining in water depths from about 

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540 to 1,476 ft (165 to 450 m) (Continental Shelf Associates, Inc., 2002). The proposed project is 

in approximately 3,853 ft (1,174 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. DOCD 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 previous EISs (MMS, 2007b; BOEM, 

2012b,c). For this DOCD, 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD Section 9b provides detail on spill response measures. 

Therefore, no significant spill impacts on fishing activities are expected. 

C.8.2 Public Health and Safety 

There are no IPFs associated with routine operations that are expected to affect public health 

and safety. Impacts of a small fuel spill and a large oil spill are addressed below. 

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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. DOCD 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 61 miles (98 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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. DOCD Section and 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 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 previous EISs (MMS, 2007b; 

BOEM, 2012b,c). For this DOCD, there are no unique site-specific issues with respect to 

employment and coastal infrastructure. A large spill could cause several types of economic 

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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 61 miles (98 km) from the nearest shoreline. Based on the OSRA modeling 

predictions (Table 3), Texas, Louisiana, and Florida coastal areas are the most likely to be 

contacted by a spill. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 

BOEM has reexamined the analyses for recreation and tourism presented in MMS (2007b, 2008) 

based on additional information and in consideration of the Macondo oil spill event. No new 

information was found that would alter the potential impacts on recreation and tourism 

(BOEMRE, 2011; BOEM, 2012c).

There are no known recreational uses of the lease area. Recreational resources and tourism in 

coastal areas would not be affected by routine activities due to the distance from shore. 

Compliance with NTL 2012-BSEE-G01 will minimize the chance of trash or debris being lost 

overboard from the drilling rig and subsequently washing up on beaches. 

Impacts of a Small Fuel Spill 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations including fuel transfer. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the potential for impacts. DOCD 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; BOEM, 2012b,c). For this DOCD, there are no unique site-specific issues with 

respect to these impacts. 

Impacts on recreation and tourism would vary depending on the duration of the spill and its fate 

including the effectiveness of response measures. A large spill that reached coastal waters and 

shorelines could adversely affect recreation and tourism by contaminating beaches and 

wetlands, resulting in negative publicity that encourages people to stay away. Based on OSRA 

modeling as summarized in Table 3, Plaquemines Parish, Louisiana, is the area most likely to be 

contacted by a spill. However, shorelines from Galveston, Texas, to the Florida Panhandle could 

be contacted. The shorelines along Galveston, Texas, include popular beaches and recreational 

sites. 

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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

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and reduce the impacts. DOCD 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 lease sale EISs (MMS, 2007b; 

BOEM, 2012b,c). 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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 934 is 

not in a designated Military Warning Area. Shell will comply with BOEM requirements and lease 

stipulations to avoid impacts on uses of the area by military vessels and aircraft. 

The archaeological surveys conducted by C&C Technologies, Inc. (2012) and Fugro GeoServices, 

Inc. (2005) 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. 

There are no IPFs from routine project activities that are likely to affect shipping or other marine 

uses. Physical disturbance to existing wells, flowlines, and umbilicals will be prevented by a 

152-m (500-ft) avoidance zone established around these features. A large oil spill is the only 

relevant accident IPF. A small fuel spill would not have 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 

lease block is not located within any USCG-designated fairway or shipping lane. In the event of a 

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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 

DOCD Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate 

and reduce the impacts. DOCD 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 and 

BOEM also analyzed the cumulative impacts of OCS development activities similar to those 

planned in this DOCD in several documents. The level and types of activities planned in Shell's 

DOCD 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) and the Final 

Programmatic EIS for OCS Oil and Gas Leasing Program: 2012-2017 (BOEM, 2012a). 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, Final EISs, and Programmatic 

EIS (MMS, 2007b; BOEM, 2012a,b). 

Description of Activities Reasonably Expected to Occur in the Vicinity of Project Area. Other 

exploration and development activities may occur in the vicinity of lease block MC 934. Shell 

does not anticipate other projects in the vicinity of the project area beyond the types of projects 

analyzed in the Multisale, Supplemental, and Programmatic EISs (MMS, 2007b, 2008; BOEM, 

2012a,b,c).

Cumulative Impacts of Activities in the DOCD. 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 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 DOCD 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 DOCD, 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. 

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C.9.1 Cumulative Impacts to Physical/Chemical Resources 

The work planned in this DOCD 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). 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 DOCD 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 DOCD. 

Water Quality. Shell’s project will result in some minor water quality impacts due to the 

NPDES-permitted discharge of SBM cuttings, treated sanitary and domestic wastes, excess 

cement, non-contact cooling water, deck drainage, desalination unit brine, uncontaminated fire 

water and ballast water. These effects are expected to be minor (localized to the area within a 

few hundred meters of the drilling rig), and temporary (lasting only hours longer than the 

disturbance or discharge). Any cumulative effects to water quality are expected to be negligible. 

Archaeological Resources. MC 934 is on the list of archaeology survey blocks (BOEM, 2012c). 

Archaeological assessments by C&C Technologies, Inc. (2012) and Fugro GeoServices, Inc. (2005) 

indicated the presence of 31 sonar contacts and 5 marine avoidance zones in the lease area, 

which will be avoided by 100 ft (30 m) and 50 ft (15 m), respectively. Also, the lease area is well 

beyond the 197-ft (60-m) depth contour used by the BOEMRE as the seaward extent for 

prehistoric archaeological site potential in the Gulf of Mexico. Therefore, Shell’s operations will 

have no cumulative impacts on historic shipwrecks or prehistoric archaeological resources. 

New Information. New information included in the most recent Programmatic, Supplemental, 

and Final EISs (BOEMRE, 2011; BOEM, 2012a,b,c) has been incorporated into the EIA, where 

applicable. 

C.9.2 Cumulative Impacts to Biological Resources 

The work planned in this DOCD is limited in geographic scope and duration, and the impacts on 

biological resources will be correspondingly limited. 

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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-lease-sale 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, duration, 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 Programmatic, Supplemental, 

and Final EISs (BOEMRE, 2011; BOEM, 2012a,b,c) has been incorporated into the EIA, where 

applicable. 

C.9.3 Cumulative Impacts to Socioeconomic Resources 

The work planned in this DOCD 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. 

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Shell’s proposed activities will have negligible cumulative impacts on socioeconomic resources. 

There are no IPFs associated with routine operations that are expected to affect public health 

and safety, employment and infrastructure, recreation and tourism, land use, or other marine 

uses. Due to the distance from shore, it is unlikely that any recreational fishing activity is 

occurring in the project area, and it is unlikely that any commercial fishing activity other than 

longlining occurs at or near the project area. The project will have negligible impacts on fishing 

activities. 

New Information. New information included in the most recent Programmatic, Supplemental, 

and Final EISs (BOEMRE, 2011; BOEM, 2012a,bc) has been incorporated into the EIA, where 

applicable. 

D. Environmental Hazards 

D.1 Geologic Hazards 

The shallow hazards assessment included in this DOCD, based on the shallow hazards reports by 

Fugro McClelland (1990) and C&C Technologies, Inc. (2012), concludes that the wellsites are free 

of any major geological hazards and are suitable for the proposed activities. There are no fluid 

expulsion features or faults within 2,000 ft (600 m) of the well proposed locations based on 

results of a high-resolution geophysical survey consisting of frequency-enhanced 

three-dimensional seismic, enhanced surface renderings, autonomous underwater vehicle 

surveys, and side-scan sonar. 

See DOCD 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 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. 

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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 DOCD 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 Ocean Sciences Inc. Contributors included the following: 

Tracy Albert (Regulatory Specialist, Regulatory Compliance Consultants of LA, LLC); 

Jeffrey McMenis (Environmental Engineer, Shell Exploration & Production Co.); 

Carlyle Kalloo (Senior Scientist, CSA Ocean Sciences Inc.); 

John Thompson (Senior Scientist, CSA Ocean Sciences Inc.); 

Neal Phillips, Ph.D. (Senior Scientist, CSA Ocean Sciences Inc.); 

Deborah Fawcett (Project Scientist, CSA Ocean Sciences Inc.); 

Keith VanGraafeiland (GIS/Remote Sensing Specialist, CSA Ocean Sciences Inc.); and 

Kim Dunleavy (Technical Editor, CSA Ocean Sciences Inc.). 

I. References 

Barkaszi, M.J., M. Butler, R. Compton, A. Unietis, and B. Bennet. 2012. Seismic survey mitigation measures and 

marine mammal observer reports. U.S. Department of the Interior, Bureau of Ocean Energy Management, 

Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 2012-015. 53 pp. 

Barkuloo, J.M. 1988. Report on the conservation status of the Gulf of Mexico sturgeon, Acipenser oxyrinchus 

desotoi. U.S. Department of the Interior, U.S. Fish Wildlife Service, Panama City, FL. 33 pp. 

Bélanger, L. and J. Bédard. 1989. Responses of Staging Greater Snow Geese to Human Disturbance. Journal of 

Wildlife Management 53:713-719.

Biggs, D.C. and P.H. Ressler. 2000. Water column biology, pp. 141-187. In: Continental Shelf Associates, Inc. 

Deepwater Program: Gulf of Mexico Deepwater Information Resources Data Search and Literature Synthesis. 

Volume I: Narrative Report. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA. OCS Study MMS 2000-049. 

Boehm, P., D. Turton, A. Raval, D. Caudle, D. French, N. Rabalais, R. Spies, and J. Johnson. 2001. Deepwater 

program: Literature review, environmental risks of chemical products used in Gulf of Mexico deepwater oil 

and gas operations. Volume I: Technical report. U.S. Department of the Interior, Minerals Management 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2001-011. 326 pp. 

Brooke, S. and W.W. Schroeder. 2007. State of deep coral ecosystems in the Gulf of Mexico region: Texas to the 

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SECTION 19: ADMINISTRATIVE INFORMATION

A. Exempted Information Description (Public Information Copies Only) 

The following attachments were excluded from the public information copies of this plan: 

1b. OCS Plan Information form – Bottom hole locations & proposed total depth 

2c. Production Information 

3a. Geologic Description 

3b. Structure Contour Maps 

3c. Interpreted 2D or 3D seismic line(s) 

3d. Cross Section(s) 

3g. Top hole prognosis and power spectrum diagram 

4b. H2S Classification Information 

5. Mineral Resource Conservation information 

B. Bibliography 

Shallow Hazards Report, Blocks 891, 934, and 935, Mississippi Canyon Area, Gulf of Mexico, prepared by 

Fugro McClelland, report #0201-0841, November 4, 1990. Deep-Towed Side Scan Sonar and SubBottom Profiler data, Sparker data. 

Shell Exploration and Production Archaeological and Hazard Report, Blocks 890-979, Mississippi Canyon 

Area, U.S. Gulf of Mexico, prepared by C&C Technologies, July, 2012, Project 100231. AUV data 

consisting of side scan sonar and sub-bottom profiler. 

C&C Technologies, Shell Exploration and Production Archaeological and Hazard Report, Blocks 890-979, 

Mississippi Canyon Area, U.S. Gulf of Mexico, dated October, 2010, Project #100231-100420. Data: AUV 

data consisting of side scan sonar and sub-bottom profiler. 

Fugro-Geoservices, Inc., Shell Deepwater Development Systems, Inc., Archaeological Assessment, Blocks 

890-892, 934-936, & 978-980, Mississippi Canyon Area, Gulf of Mexico, Report #2405-1366, dated 

December, 2005. Data: Deep-towed Side Scan Sonar and Sub-bottom Profiler 

Shell Regional OSRP, 2013 

EIA prepared by CSA International, Inc. 

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