UNITED STATES GOVERNMENT MEMORANDUM

To: Public Information (MS 5030)

Plans Section, Office of Field 

Operations (MS 5231)

Public Information copy of Exploration Plan

Control # - S-07621

Type - Supplemental Exploration Plan

Lease(s) - OCS-G05868 Block - 809 Mississippi Canyon Area

OCS-G06981 Block - 808 Mississippi Canyon Area

Operator - Shell Offshore Inc.

Drill & Suspend - Wells HH, II, JJ, KK, LL, & MM

DP Semisubmersible; Drillship

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

should be addressed in an Environmental Assessment.

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

Mohammad Ashfaq

Plan Coordinator

Description -

Rig Type -

Subject:

From:

September 3, 2013
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

July 5, 2013 

Bureau of Ocean Energy Management 

1201 Elmwood Park Boulevard 

New Orleans, LA 70123-2394 

 

Attn: Plans Group GM 1053C 

SUBJECT: Supplemental Exploration Plan 

 OCS-G 5868 & 6981, Mississippi Canyon Blocks 809 & 808 

 Offshore Louisiana 

Gentlemen: 

 

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

Shell Offshore Inc. (Shell) requests your approval of this Supplemental Exploration Plan to drill Well Locations HH, II, 

JJ, KK, LL & MM. Operations are targeted to commence in January 2014. 

This plan consists of a series of attachments describing our intended operations. The attachments we desire to be 

exempted from disclosure under the Freedom of Information Act are marked “Proprietary” and excluded from the 

Public Information Copies of this submittal. The cost recovery fee receipt is attached to the Proprietary copy of the 

Plan. 

Should you require additional information, please contact Tracy Albert at 504.425.4652 or tracy.albert@shell.com. 

Sincerely, 

Sylvia A. Bellone 

Page 1 Public Information Copy
SHELL OFFSHORE INC. 

SUPPLEMENTAL EXPLORATION PLAN 

for 

OCS-G 5868, Mississippi Canyon Block 809

OCS-G 6981, Mississippi Canyon Block 808 

MISSISSIPPI CANYON BLOCK 854 UNIT NO. 754393012 

PUBLIC INFORMATION COPY 

JULY 2013

PREPARED BY: 

Tracy W. Albert 

 Regulatory Specialist 

504.425.4652 

tracy.albert@shell.com

Page 2 Public Information Copy
REVISIONS TABLE:

Date of Request Plan Section What was Corrected Date Resubmitted

7/16/2013 NA

 NA 

Provided BOEM copy of 

C&C report

Cost recovery fee 

(Proprietary only)

 7/18/2013

 7/22/2013

8/7/2013 Section 9 Removed note 8/8/2013

Page 3 Public Information Copy
SUPPLEMENTAL EXPLORATION PLAN 

OCS-G 5868, Mississippi Canyon Block 809

OCS-G 6981, Mississippi Canyon Block 808 

OFFSHORE LOUISIANA 

TABLE OF CONTENTS

SECTION 1 PLAN CONTENTS 

SECTION 2 GENERAL INFORMATION 

SECTION 3 GEOLOGICAL AND GEOPHYSICAL INFORMATION 

SECTION 4 HYDROGEN SULFIDE - H2S INFORMATION 

SECTION 5 MINERAL RESOURCE CONSERVATION INFORMATION

SECTION 6 BIOLOGICAL, PHYSICAL AND SOCIOECONOMIC 

 INFORMATION 

SECTION 7 WASTE AND DISCHARGE INFORMATION 

SECTION 8 AIR EMISSIONS INFORMATION 

SECTION 9 OIL SPILLS INFORMATION 

SECTION 10 ENVIRONMENTAL MONITORING INFORMATION 

SECTION 11 LEASE STIPULATIONS INFORMATION 

SECTION 12 ENVIRONMENTAL MITIGATION MEASURES INFORMATION 

SECTION 13 RELATED FACILITIES AND OPERATIONS INFORMATION 

SECTION 14 SUPPORT VESSELS AND AIRCRAFT INFORMATION 

SECTION 15 ONSHORE SUPPORT FACILITIES INFORMATION 

SECTION 16 SULPHUR OPERATIONS INFORMATION 

SECTION 17 COASTAL ZONE MANAGEMENT ACT (CZMA) INFORMATION 

SECTION 18 ENVIRONMENTAL IMPACT ANALYSIS (EIA) 

SECTION 19 ADMINISTRATIVE INFORMATION 

 

 

 

Page 4 Public Information Copy
Acronyms and Abbreviations 

ADIOS Automated Data Inquiry for Oil Spills 

bbl barrel 

BML below mud line 

BOEM Bureau of Ocean Energy Management 

BOEMRE Bureau of Ocean Energy Management, 

Regulation and Enforcement 

BOPD barrels of oil per day (bbl/d) 

BSEE Bureau of Safety and Environmental 

Enforcement 

C&C C&C Technologies, Inc. 

CFR Code of Federal Regulations 

CH4 methane 

CO carbon monoxide 

CO2 carbon dioxide 

DP dynamically positioned 

DPS distinct population segment 

EFH Essential Fish Habitat 

EIA Environmental Impact Analysis 

EIS Environmental Impact Statement 

EP Exploration Plan 

ESA Endangered Species Act 

FAD fish-attracting device 

Fugro Fugro-McClelland Marine 

Geosciences, Inc. 

GMFMC Gulf of Mexico Fishery Management 

Council 

H2S hydrogen sulfide 

HAPC Habitat Area of Particular Concern 

ICS Interim containment system 

IPF impact-producing factor 

MC Mississippi Canyon 

MARPOL International Convention for the 

Prevention of Pollution from Ships 

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 

NRC National Research Council 

NTL Notice to Lessees and Operators 

NWR National Wildlife Refuge 

OCS Outer Continental Shelf 

OCSLA Outer Continental Shelf Lands Act 

OSAT Operational Science Advisory Team 

OSRA Oil Spill Risk Analysis 

OSRP Oil Spill Response Plan 

PAH polycyclic aromatic hydrocarbons 

PM particulate matter 

SBM synthetic-based mud 

Shell Shell Offshore Inc. 

SO2 sulfur dioxide 

SOx sulfur oxides 

SWIM Surface Water Improvement and 

Management 

UME Unusual Mortality Event 

U.S.C. United States Code 

USCG U.S. Coast Guard 

USDOI U.S. Department of the Interior 

USEPA U.S. Environmental Protection Agency 

USFWS U.S. Fish and Wildlife Service 

VOC volatile organic compound 

WCD worst case discharge 

WMA Wildlife Management Area 

Page 5 Public Information Copy
SECTION 1: PLAN CONTENTS

A. DESCRIPTION, OBJECTIVES & SCHEDULE

Shell Offshore Inc. (Shell) is submitting a supplemental exploration plan (EP/plan) for Mississippi Canyon (MC) Block 

809 and 808, OCS-G 5868 and 6981 respectfully. This plan includes six proposed exploration wells: HH, II, JJ, KK, 

LL & MM drilled from the surface location in MC 809. The wells will be drilled and temporarily abandoned with 

cement plugs and corrosion caps in accordance with 30 CFR 250.1721 until the wells are completed and developed 

under future plans. If the wells are unsuccessful, they will be permanently plugged and abandoned in accordance with 

the Bureau of Safety and Environmental Enforcement (BSEE) regulations. These wells will be part of the Mississippi 

Canyon Block 854 Unit No. 754393012. 

The drilling activities are planned to commence on or about January 2014 and last approximately 144 days per well. 

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

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

The lease area is 55 statute miles from the nearest shoreline, 109 statute miles from the onshore support base at 

Port Fourchon, Louisiana and 80 statute miles from the helicopter base at Boothville, Louisiana. Water depths at 

the well sites range from 3,615’ to 3,645’ (Attachment 1A).

The proposed rig is either a dynamically positioned (DP) semi-submersible (Noble Jim Day or similar) or a Drill Ship 

(Noble Don Taylor or similar); both are self-contained drilling vessels with accommodations for a crew which include 

quarters, galley and sanitation facilities. The rigs will comply with the requirements in the Interim Final Rules. The 

drilling activities will be supported by the support vessels and aircraft as well as onshore support facilities as listed in 

Sections 14 and 15 of the 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 809 drilling program. 

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

the design and execution of wells and into building and maintaining staff competence. In the unlikely event of a spill, 

Shell’s Regional Oil Spill Response Plan (OSRP) is designed to contain and respond to a spill that meets or exceeds the 

worst case discharge (WCD) as detailed in Section 9 of this EP. The WCD does not take into account potential flow 

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

to invest in research and development to improve safety and reliability of our well systems. All operations will be 

conducted in accordance with applicable federal and state laws, regulations and lease and permit requirements. Shell 

will have trained personnel and monitoring programs in place to ensure such compliance. 

B. LOCATION

See attached location plat (Attachments 1A) and BOEM forms (Attachments 1B through 1H). 

C. RIG SAFETY AND POLLUTION FEATURES 

The rig (Noble Jim Day or similar or Noble Don Taylor 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. 

Page 6 Public Information Copy
DRAIN SYSTEM POLLUTION FEATURES 

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

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

plate to prevent debris from entering the system. 

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

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

the Rig. 

1) Non-contaminated Drains 

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

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

where it is unlikely that hydrocarbons will be found. 

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

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

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

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

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

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

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

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

deployment as appropriate) and reported immediately. 

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

place as needed to ensure a proper seal. 

2) Contaminated Drains 

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

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

3) Mud Drain System 

None 

4) Oily Water Processing 

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

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

an oil record log has to be kept according to instructions included in the log. Any and all pollution pans are subjected 

to a sheen test before being pumped out. If the water passes the sheen test then it is pumped overboard. If it does 

not pass the sheen test then the water/oil mixture is pumped to a dirty oil tank and sent to shore for disposal. All 

waste oil that is sent in to be disposed of is recorded in the MODU’s oil log book.

All discharges will be in accordance with applicable NPDES permits. See Section 18, EIA. 

5) Lower Hull Bilge System 

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

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

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

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

Page 7 Public Information Copy
 The pontoon bilge pumps are operable from the Bridge and have audible and visual bilge alarms set for 

high and low levels. 

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

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

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

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

– Portable submersible pumps 

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

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

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

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

they can be turned on by hand. 

6) Emergency Bilge System 

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

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

The ballast pumps can be supplied from the emergency switchboard. 

7) Oily Water Drain/Separation System 

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

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

disposal. On board all drilling Units, an oil record log has to be kept according to instructions included in the log. The 

rig floor has two skimmer tanks and each is subjected to a sheen test before pumping overboard to ensure 

environmental safety. All three anchor winch windlasses have skimmer tanks and are subjected to sheen tests before 

discharge as well. 

8) Drain, Effluent and Waste Systems 

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

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

non-hazardous drains from nonhazardous areas. 

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

the drainage systems are segregated. 

 The rig drainage systems tie into oily water separators that take out elements in the drainage that could 

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

9) Rig Floor Drainage 

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

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

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

further to reduce oil content to less than 15 ppm. 

10) Columns #3 & 4 

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

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

then discharge the clean product to sea. 

11) Main Engine Rooms 

The engine rooms have their own drainage and handling system. The engine rooms are outfitted with a dirty oil tank 

and the drainage in the tank is processed through the separator, the waste from the separator goes back to the dirty 

oil tank and the clean water (less than 15ppm) goes overboard. 

Page 8 Public Information Copy
12) Helideck Drains 

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

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

Operating configurations are as follows: 

– The overboard piping valves and hydrocarbons take on valves are closed and locked. To unlock overboard or 

take on valves a permit has to be filled out. 

– The oily water collection tank overflow valve is closed. 

– The drill floor drains are lined-up to the drill floor skimmer tank. The Skimmer tanks have a high alarm which 

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

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

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

– The oily water separator continuously circulates the oily water collection tank. Waste oil is discharged into 

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

pumped overboard, which is controlled/monitored by the oil content detector, set at 15 ppm. 

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

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

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

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

is a high audible alarm on the ballast control panel. 

D. Storage Tanks – Noble Jim Day DP Semi-Submersible or similar:

Type of Storage Tank Type of

Facility

Tank

Capacity 

(bbls)

Number of

Tanks

Total

Capacity 

(bbls)

Fluid

Gravity (Specific)

Diesel Tank in stbd 1 

80% fill in all hull tanks

Drilling Rig 3597 1 Marine Diesel (0.91 SG)

Diesel Tank in stbd 2 Drilling Rig 2713 1 Marine Diesel (0.91 SG)

Diesel Tank in stbd 3 Drilling Rig 3456 1 Marine Diesel (0.91 SG)

Diesel Tank in stbd 4 Drilling Rig 653 1 Marine Diesel (0.91 SG)

Diesel Tank in port 1 Drilling Rig 2090 1 Marine Diesel (0.91 SG)

Diesel Tank in port 2 Drilling Rig 1366 1 Marine Diesel (0.91 SG)

Diesel Tank in port 3 Drilling Rig 4787 1 Marine Diesel (0.91 SG)

Diesel Tank in port 4 Drilling Rig 3456 1 Marine Diesel (0.91 SG)

Total storage in hull 

tanks

Drilling Rig 22118 Marine Diesel (0.91 SG)

Diesel Settling Tanks Drilling Rig 129 1 Marine Diesel (0.91 SG)

Diesel Settling Tanks Drilling Rig 129 1 Marine Diesel (0.91 SG)

Diesel Settling Tanks Drilling Rig 139 1 Marine Diesel (0.91 SG)

Diesel Settling Tanks Drilling Rig 129 1 Marine Diesel (0.91 SG)

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

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

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

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

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

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

Page 9 Public Information Copy
Storage Tanks – Noble Don Taylor Drillship or similar:

Type of Storage 

Tank

Type of

Facility

Tank

Capacity (bbls)

Number of

Tanks

Total

Capacity (bbls)

Fluid

Gravity (Specific)

Fuel oil Drilling Rig 2,889 4 11,556 Marine Diesel (0.91 SG)

Fuel oil Drilling Rig 3,225 4 12,900 Marine Diesel (0.91 SG)

Fuel oil Drilling Rig 2,887 4 11,548 Marine Diesel (0.91 SG)

Fuel oil Drilling Rig 2,680 4 10,720 Marine Diesel (0.91 SG)

Fuel oil Drilling Rig 178 8 1,424 Marine Diesel (0.91 SG)

E. Pollution Prevention Measures 

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

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

this information as part of its response to 1(c) above. 

F. Additional Measures

 

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

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

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

 All tools that come to and from the rig have their pollution pans inspected, cleaned and confirmation of 

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

 Preventive Maintenance of rig equipment includes visual inspection of hydraulic lines and reservoirs on 

routine scheduled basis. 

 All pollution pans on rig are inspected daily. 

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

tanks. 

 All used oil and fuel is collected and sent in for recycling. 

 Every drain on the rig is assigned a number on a checklist. The checklist is used daily to verify drain plugs 

are installed. 

 All trash containers are checked and emptied daily. The trash containers are kept covered. Trash is disposed 

of in a compactor and shipped in via boat. 

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

 Fuel hoses and SBM are changed on annual basis. 

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

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

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

 Shell has obtained ISO14001 certification. 

 Shell uses low sulfur fuel. 

G. Description of Previously Approved Lease Activities

These wells will be part of the Mississippi Canyon Block 854 Unit No. 754393012. 

Page 10 Public Information Copy
Attachment 1A 

Bathymetry and Surface Locations 

Page 11 Public Information Copy
Attachment 1B 

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

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

OCS PLAN INFORMATION FORM 

General Information

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

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

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

New Orleans, LA 70161-1933 Phone Number: (504) 728-4652

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

Lease(s): G05868 Area: MC Block(s): 809 Project Name (If Applicable): Mercury

Objective(s): X Oil Gas Sulphur Salt Onshore Base: Fouchon/Boothville Distance to Closest Land (Miles): 55

Description of Proposed Activities (Mark all that apply)

X Exploration drilling Development drilling

Well completion Installation of production platform

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

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

Installation of subsea wellheads and/or manifolds Commence production

Installation of lease term pipelines Other (Specify and describe) Pipeline appurtenance

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

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

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

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

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

Tentative Schedule of Proposed Activities

Proposed Activity Start Date End Date No. of Days

Drill and suspend Well HH 1/1/2014 5/25/2014 144

Drill and suspend Well II 1/1/2015 5/25/2015 144

Drill and suspend Well JJ 1/1/2016 5/24/2016 144

Drill and suspend Well KK 1/1/2017 5/25/2017 144

Drill and suspend Well LL 1/1/2018 5/25/2018 144

Drill and suspend Well MM 1/1/2019 5/25/2019 144

Description of Drilling Rig Description of Production Platform

Jackup X Drillship Caisson Tension leg platform

Gorilla Jackup Platform rig Well protector Compliant tower

Semisubmersible Submersible Fixed platform Guyed tower

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

Drilling Rig Name (If Known): Noble Jim Day (or similar)

 Noble Don Taylor (or similar) 

Spar Other (Attach Description)

Description of Lease Term Pipelines

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

N/A

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

 

Page 12 Public Information Copy
Attachment 1C 

OCS PLAN INFORMATION FORM (CONTINUED) 

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

Proposed Well/Structure Location

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

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 05868

Area Name Mississippi Canyon

Block No. 809

Blockline

Departures

(in feet)

N/S Departure: 6,273’ FSL

E/W Departure: 3,671’ FWL

Lambert X-Y 

coordinates

X: 954,071

Y: 10,223,073

Latitude/

Longitude

Latitude 28 deg 09’ 16.79” N

Longitude 89 deg 07’ 49.48" W

TVD (Feet): MD (Feet): WD (Feet): 3,635’

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): II Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 05868

Area Name Mississippi Canyon

Block No. 809

Blockline

Departures

(in feet)

N/S Departure: 5,894’ FSL

E/W Departure: 3,942’ FWL

Lambert X-Y 

coordinates

X: 954,342

Y: 10,222,694

Latitude/

Longitude

Latitude 28 deg 09’ 13.09” N

Longitude 89 deg 07’ 46.38" W

TVD (Feet): MD (Feet): Water Depth (Feet): 3,640’

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 E 

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): JJ Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 05868

Area Name Mississippi Canyon

Block No. 809

Blockline

Departures

(in feet)

N/S Departure: 6,880’ FSL

E/W Departure: 3,007’ FWL

Lambert X-Y 

coordinates

X: 953,407

Y: 10,223,680

Latitude/

Longitude

Latitude 28 deg 09’ 22.68” N

Longitude 89 deg 07’ 57.02" W

TVD (Feet): MD (Feet): Water Depth (Feet): 3,615’

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

Anchor Name

or No.

Area Block X Coordinate Y Coordinate Length of Anchor Chain on 

Seafloor

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

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

BOEM approval. We use the information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the 

Freedom of Information Act and 30 CFR 550.197. An agency may not conduct or sponsor, and a person is not required to respond to, a collection 

of information unless it displays a currently valid Office of Management and Budget Control Number. Responses are mandatory (43 U.S.C. 1334). 

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

Documents. We estimate that burden to average 600 hours with an accompanying EP, or 700 hours with an accompanying DPP or DOCD, 

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

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

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

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

Page 15 Public Information Copy
Attachment 1F 

OCS PLAN INFORMATION FORM (CONTINUED) 

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

Proposed Well/Structure Location

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

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 05868

Area Name Mississippi Canyon

Block No. 809

Blockline

Departures

(in feet)

N/S Departure: 7,700’ FSL

E/W Departure: 2,900’ FWL

Lambert X-Y 

coordinates

X: 953,300

Y: 10,224,500

Latitude/

Longitude

Latitude 28 deg 09’ 30.78” N

Longitude 89 deg 07’ 58.76" W

TVD (Feet): MD (Feet): Water Depth (Feet): 3,637’

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

Anchor Name

or No.

Area Block X Coordinate Y Coordinate Length of Anchor Chain on 

Seafloor

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

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

BOEM approval. We use the information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the 

Freedom of Information Act and 30 CFR 550.197. An agency may not conduct or sponsor, and a person is not required to respond to, a collection 

of information unless it displays a currently valid Office of Management and Budget Control Number. Responses are mandatory (43 U.S.C. 1334). 

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

Documents. We estimate that burden to average 600 hours with an accompanying EP, or 700 hours with an accompanying DPP or DOCD, 

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

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

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

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

Page 16 Public Information Copy
Attachment 1G 

OCS PLAN INFORMATION FORM (CONTINUED) 

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

Proposed Well/Structure Location

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

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 05868

Area Name Mississippi Canyon

Block No. 809

Blockline

Departures

(in feet)

N/S Departure: 7,144’ FNL

E/W Departure: 2,301’ FWL

Lambert X-Y 

coordinates

X: 952,701

Y: 10,225,496

Latitude/

Longitude

Latitude 28 deg 09’ 40.54” N

Longitude 89 deg 08’ 05.26" W

TVD (Feet): MD (Feet): Water Depth (Feet): 3,645’

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

Anchor Name

or No.

Area Block X Coordinate Y Coordinate Length of Anchor Chain on 

Seafloor

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

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

BOEM approval. We use the information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the 

Freedom of Information Act and 30 CFR 550.197. An agency may not conduct or sponsor, and a person is not required to respond to, a collection 

of information unless it displays a currently valid Office of Management and Budget Control Number. Responses are mandatory (43 U.S.C. 1334). 

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

Documents. We estimate that burden to average 600 hours with an accompanying EP, or 700 hours with an accompanying DPP or DOCD, 

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

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

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

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

Page 17 Public Information Copy
Attachment 1H 

OCS PLAN INFORMATION FORM (CONTINUED) 

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

Proposed Well/Structure Location

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

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 05868

Area Name Mississippi Canyon

Block No. 809

Blockline

Departures

(in feet)

N/S Departure: 6,519’ FNL

E/W Departure: 2,183’ FWL

Lambert X-Y 

coordinates

X: 952,583

Y: 10,226,121

Latitude/

Longitude

Latitude 28 deg 09’ 46.70” N

Longitude 89 deg 08’ 06.70" W

TVD (Feet): MD (Feet): Water Depth (Feet): 3,645’

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

Anchor Name

or No.

Area Block X Coordinate Y Coordinate Length of Anchor Chain on 

Seafloor

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

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

BOEM approval. We use the information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the 

Freedom of Information Act and 30 CFR 550.197. An agency may not conduct or sponsor, and a person is not required to respond to, a collection 

of information unless it displays a currently valid Office of Management and Budget Control Number. Responses are mandatory (43 U.S.C. 1334). 

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

Documents. We estimate that burden to average 600 hours with an accompanying EP, or 700 hours with an accompanying DPP or DOCD, 

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

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

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

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

Page 18 Public Information Copy
SECTION 2: GENERAL INFORMATION

A. Application and Permits

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

need to be obtained. Prior to beginning exploration operations, an Application for Permit to Drill will be submitted 

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

B. Drilling Fluids 

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

C. Production

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

DOCDs. 

D. Oil Characteristics

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

case of DOCDs. 

E. New Or Unusual Technology

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

activities in this EP. 

F. Bonding

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

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

Surety Bonds” and additional security under 30 CFR 256.53(d) and National NTL No. 2008-N07, “Supplemental 

Bond Procedures.”

G. Oil Spill Financial Responsibility (OSFR)

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

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

Spill Financial Responsibility for Covered Facilities.”

H. Deepwater well control statement

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

emergency well control operations if required. 

I. Suspension of Production

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

in the case of DOCDs. 

Page 19 Public Information Copy
J. Blowout scenario

Summary 

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

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

regulations, rules and Notices to Lessees. 

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

containment, and recovery. 

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

goes into design and execution of wells and into building and maintaining staff competence. Shell continues 

to invest independently in R&D to improve safety and reliability of our well systems. 

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

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

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

resources necessary to respond to this WCD scenario. The capabilities for on-water recovery, aerial and 

subsea dispersant application, in-situ burning, and nighttime monitoring and tracking have been significantly 

increased. 

The WCD blowout scenario for this plan is calculated for the MC 809 Well KK location penetration of the target 

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

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

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

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

barriers, and early intervention including containment capabilities. 

Uncontrolled blowout (volume first day) 425,000 bbl 

Uncontrolled blowout rate (first 30-days average daily rate) 391,000 bopd 

Duration of flow (days) based on relief well 144 days

Total volume of spill (bbls) for 144 days 51 MMBO

Table 2.1. Mercury Worst Case Discharge Summary 

The exploration prospect is located approximately 55 statute miles south-southeast of the nearest Louisiana 

shoreline in the Gulf of Mexico, in water depths of 3300-3800’ across the prospect. The structural component of the 

prospect is defined by a three-way closure against salt in the targets. There are multiple objective intervals in the 

proposed well with highest flow potential in the targets, and the MC 809 KK well is expected to have the highest flow 

rates. The alternate well locations (HH, II, JJ, LL and MM) were also evaluated; however, their flow rates are lower 

than the WCD calculated for the MC 809 KK well. 

1) Purpose 

Pursuant to 30 CFR 250.213(g), 250.219, 250.250, and NTL 2010-N06, this document provides a blowout scenario 

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

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

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

parameters that are derived from the regional formation of offset well data and seismic data. These parameters are 

better than or consistent with the estimates used by Shell to justify the investment. Therefore, these assumed 

parameters were used to calculate the WCD. They do not reflect probabilistic estimates. 

2) Background 

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

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

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

Page 20 Public Information Copy
3) Information Requirements 

a) Blowout scenario 

All well locations addressed in this EP were assessed for WCD. The MC 809 well from the KK location represents the 

highest flow potential. The KK well penetrates the Miocene objective interval as outlined in the Geological and 

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

casing program, and using a DP MODU with a marine riser and subsea blowout preventer (BOP). A hydrocarbon 

influx and a well control event are modeled to occur from reservoirs in the objective interval. The modeled blowout 

results in unrestricted flow from the well at the seafloor, which represents the WCD (no restrictions in wellbore, 

failure/loss of the subsea BOP, and a blowout to the seabed). 

b) Estimated flow rate of the potential blowout 

Category EP 

Type of Activity Drilling 

Facility Location (area/block) MC-809

Facility Designation MODU 

Distance to Nearest Shoreline (Statute miles) 55

Uncontrolled blowout (volume first day) 425,000 bbl 

Uncontrolled blowout rate (first 30-days average daily rate) 391,000 bopd 

Table 2.2 Estimated Flow Rates of a Potential Blowout 

c) Total volume and maximum duration of the potential blowout 

Duration of flow (days) 144 days total duration to drill relief well 

(14 days rig demobilization and mobilization, 91 days spud to TD, 39 

days ranging). 

Total volume of spill (bbls) 51 MMBO based on 144 days flowing. 

Note: From GAP/Prosper/MBAL model

Table 2.3 Estimated Duration and Volume of a Potential Blowout 

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

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

further demonstrates this decline. At very short times, e.g. during the first 24 hours, the pressure profile in the 

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

time, and as a result the rate declines. At somewhat longer time scales, effects such as reservoir voidage and the 

impact of boundaries can cause the rate to drop continuously with production. Simulation and material balance 

models can include these effects and form the basis of the NTL 2010-N06 calculations for 24-hour and 30-day rates 

as well as maximum duration volumes. 

Page 21 Public Information Copy
d) Assumptions and calculations used in determining the worst case discharge (Proprietary) 

e) Potential for the well to bridge over 

Mechanical failure/collapse of the borehole in a blowout scenario is influenced by several factors including in-situ 

stress, rock strength and fluid velocities at the sandface. Based on the nodal analysis and reservoir simulation 

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

fluid velocities inherent in the worst case discharge, and the scenario as defined where the formation is not 

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

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

bridging. 

f) Likelihood for intervention to stop the blowout. 

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

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

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

making blowouts extremely rare events. 

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

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

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

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

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

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

of the necessary equipment and systems for well containment. As a result, industry and government are better 

equipped and prepared today to contain an oil well blowout in deepwater. Shell is further analyzing these advances 

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

control incident. 

Pursuant to NTL 2010-N10 Shell will provide additional information regarding our containment capabilities in a 

subsequent filing. 

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

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

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

rigs in 2013 – 2018 timeframe. The dynamically positioned rigs under contract, the Noble Danny Adkins, Noble 

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

However, moored rigs, like the Transocean Deepwater Nautilus, can also be used in some scenarios. Additionally, in 

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

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

rig. Shell’s current contracted rigs capable of operating at Mercury water depths and reservoir depths without 

constraints are in the following table: 

Rig Name Rig Type

Noble Danny Adkins Dynamically positioned semisubmersible

Noble Globetrotter I Dynamically positioned drillship

Noble Jim Day Dynamically positioned semisubmersible

Noble Bully I Dynamically positioned drillship

Transocean Deepwater Nautilus Moored semisubmersible

Table 2.4 Shell contracted rigs capable at Mercury 

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

basis. 

Page 22 Public Information Copy
h) Time taken to contract a rig, move it onsite, and drill a relief well 

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

2.4 lists the Shell contracted rigs capable of operating at Mercury. It is expected to take an average of 11 days to 

safely secure the well that the rig is working on up to the point the rig departs location, and an additional 3 days 

transit to mobilize to the relief well site depending on distance to the site. The relief well will take approximately 91 

days to drill down to the last casing string above the blowout zone, plus approximately 39 days for precision ranging 

activity to intersect the blowout well bore. The total time to mobilize and drill a relief well would be 144 days for the 

Mercury wells. 

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

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

initiation of relief well drilling operations. Shell has three deepwater anchor handlers, the Laney, Dino, and Ross 

Chouest, on long term contract to support its moored rigs. It is not possible to drill relief wells from any existing 

platforms due to the distance to reach the sub-surface. 

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

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

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

highlighted the importance of these practices. The lessons learned from the investigation are, and will continue to 

be, incorporated into our operations. 

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

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

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

design and operations on the well. 

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

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

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

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

drilling begins. 

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

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

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

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

depth and breadth of internal drilling and operational expertise. Third party vendors and rig contractors are involved 

in all stages of the planning, providing their specific expertise. A Drill the Well On Paper (DWOP) exercise is 

conducted with rig personnel and vendors involved in execution of the well. This forum communicates the well plan, 

and solicits input as to the safety of the plan and procedures proposed. 

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

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

equipment, which meets or exceeds the strictest of Shell, industry, or regulatory requirements. Well tangibles are 

governed by our internal quality assurance/control standards and industry standards. 

MWD/LWD/PWD Tools: Shell intends to use these tools at Mercury. 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 

Page 23 Public Information Copy
are in close communication with both the offshore drilling foremen and onshore Shell representative(s) to report any 

observed anomalies so appropriate action can be taken. 

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

traditional rig-site monitoring since 2003. Well site operations are monitored 24/7 virtually by onshore teams 

consisting of geoscientists, petrophysicists, well engineers, and monitoring specialists. The same real time well 

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

redundancy. 

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

includes internal professional examinations to verify competency. Other industry training in well control, such as by 

International Association of Drilling Contractors (IADC) and International Well Control Forum (IWCF) are also 

mandated. Progressions have elements of competency and Shell continues to have comprehensive internal training 

programs. The best systems and processes can be defeated by lack of knowledge and/or improper values. We 

believe that a combination of HSE tools (e.g. stop work, pre-job analysis, behavior based safety, DWOPs, audits), 

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

culture in our operations. 

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

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

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

Shell that addresses the overall organization response to an emergency situation. Resources are dedicated to these 

systems and drills are run frequently to test preparedness (security, medical, oil spill, and hurricane). This same 

framework is activated and tested during hurricane evacuations, thereby maintaining a fresh and responsive team. 

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

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

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

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

information gathering forms, a generic description of relief well drilling, strategy and guidelines, intervention 

techniques and equipment, site safety management, exclusion zones, and re-boarding. 

As set forth in 3f of this document, Shell is currently analyzing recent advances in containment technology and 

equipment and will incorporate them as they become available. 

k) Arrangements for drilling a relief well 

The size of the Shell contracted rig fleet in the GOM from 2013-2018 ensures that there is adequate well equipment 

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

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

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

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

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

All proposed Mercury locations were evaluated and Location KK was determined to have the greatest WCD volume. 

Shell has designed a response program (Regional OSRP) based upon a regional capability of responding to a range 

of spill volumes, from small operational spills up to and including the WCD from a well blowout. Shell’s program is 

developed to fully satisfy federal oil spill planning regulations. The Regional OSRP presents specific information on 

the response program that includes a description of personnel and equipment mobilization, the incident 

management team organization and the strategies and tactics used to implement effective and sustained spill 

containment and recovery operations. 

Page 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. Stratigraphic Column with Time vs Depth Table

Proprietary data 

F. Shallow Hazards Report

The following report was used for our analysis: 

Fugro-McClelland Marine Geosciences, Inc, Shallow Hazards Report, Blocks 808, 809, and 853, Mississippi 

Canyon Area, Gulf of Mexico (for Exxon), Report No. 0201-1760, dated November 6, 1992. Data includes: 

Air Gun, subbottom profiler, echosounder 

Fugro-McClelland Marine Geosciences, Inc, Shallow Hazards Report, Blocks 808, 809, 810 and 853, 

Mississippi Canyon Area, Gulf of Mexico, Report No. 0201-1412, dated July 10, 1991. Data includes: 

Sparker, mini-sparker, echosounder, deep-towed Side Scan Sonar, Sub-Bottom Profiler 

Shell Offshore, Inc, Shallow Hazards Report, Blocks 810 and 854, Mississippi Canyon Area, Gulf of Mexico, 

dated November, 1988. Data includes: Sparker, mini-sparker, echosounder, deep-towed Side Scan Sonar, 

Sub-Bottom Profiler 

G. Shallow Hazards Assessment

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

H. Geochemical Information

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

I. Future G&G Activities

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

Page 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, classify the area in the 

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

C. H2S Contingency Plan

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

the proposed exploration activities. 

D. Modeling Report

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

therefore have not included modeling for H2S.

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

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

the case of DOCDs. 

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

A. Chemosynthetic Communities Report

Shallow Hazards Reports and Data: 

Fugro-McClelland Marine Geosciences, Inc, Shallow Hazards Report, Blocks 808, 809, and 853, Mississippi 

Canyon Area, Gulf of Mexico (for Exxon), Report No. 0201-1760, dated November 6, 1992. Data includes: Air 

Gun, subbottom profiler, echosounder 

Fugro-McClelland Marine Geosciences, Inc, Shallow Hazards Report, Blocks 808, 809, 810 and 853, Mississippi 

Canyon Area, Gulf of Mexico, Report No. 0201-1412, dated July 10, 1991. Data includes: Sparker, minisparker, echosounder, deep-towed Side Scan Sonar, Sub-Bottom Profiler 

Shell Offshore, Inc, Shallow Hazards Report, Blocks 810 and 854, Mississippi Canyon Area, Gulf of Mexico, 

dated November, 1988. Data includes: Sparker, mini-sparker, echosounder, deep-towed Side Scan Sonar, 

Sub-Bottom Profiler 

Archaeological Report and Data: 

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

Canyon Area, Project No. 083986-084109, dated February 2009. Data includes: AUV side-scan sonar and 

sub-bottom profiler. 

Proposed Locations and Coordinates 

Proposed Location

MC 809

X

Coordinate

Y

Coordinate

Lease Calls

FNL/FSL

Lease Calls

FEL/FWL Water Depth

Prop Loc HH 954,071 10,223,073 6,273’ FSL 3,671’ FWL 3,635

Prop Loc II 954,342 10,222,694 5,894’ FSL 3,942’ FWL 3,640

Prop Loc JJ 953,407 10,223,680 6,880’ FSL 3,007’ FWL 3,615

Prop Loc KK 953,300 10,224,500 7,700’ FSL 2,900’ FWL 3,637

Prop Loc LL 952,701 10,225,496 7,144’ FNL 2,301’ FWL 3,645

Prop Loc MM 952,583 10,226,121 6,519’ FNL 2,183’ FWL 3,645

Coordinates are in UTM 316, NAD27 

Site Assessment, MC 809, Proposed Location HH: 

Mississippi Canyon 809, Proposed Location HH is located in a water depth of approximately 3635 feet. 

Proposed Location HH will be positioned 303’ east (down-thrown) of a minor seafloor fault with less than 5’ of 

offset and 521’ east (down-thrown) of the next closest minor fault with less than 5 feet of offset. MC 809, 

Proposed Location HH is not expected to penetrate any faults. 

The stratigraphy at the site of MC 809, Proposed Location HH consists of: 

 Unit 1 (Seafloor – 481’ BML) 481’ of hemipelagic mud with muddy MTD’s in lower part of Unit 1

Unit 2 (481’ – 1500’ BML) 1019’ total, 394’ of mud, 100’ of MTD’s (875’ – 975’ BML), 525’ of 

 potential laminated levee sands (975’ – 1500’ BML)

Unit 3 (1500’ – 2027’ BML) 527’ total, 265’ of channel sands (1500’ – 1765’ BML), Canyon Base 

 1765’ BML, 145’ of sand-prone Blue Unit (1765’ – 1910’ BML), 117’ of muddy sediments

Unit 4 (2027’ – 2891’ BML) 864’ of mud-prone sediments with minor thin sand intervals in top 

 part of Unit 4 

Unit 5 (2891’ – 4326’ BML) 1435’ of mud interbedded with sand in upper part of Unit 5

Page 28 Public Information Copy
Shallow Water Flow Potential: 

 Low - Seafloor – 481’ BML

 Moderately Low - 481’ – 1500’ BML

 Moderate - 1500’ – 2027’ BML 

 Moderately Low – 2027’ – 4326’ BML

Shallow Gas Potential 

 Low – Seafloor – 481’ BML

 Moderately Low – 481’ – 2891’ BML

 Moderate – 2891’ – 4326’ BML

Buried amplitudes are identified within the following units: 

 Unit 2 (481-1500’ BML) 488’ to Southwest

Unit 3 (1500’-2027’ BML) 895’ to Southwest

Unit 5 (2891’-4326’ BML) 717’ to North/Northwest

Unit 6 (below 4326’ BML) 595’ to South/Southwest

MC 809, Proposed Location HH will not penetrate any of these buried amplitudes. 

Benthic/Anchor Assessment, MC 809, Proposed Location HH (no anchors – DP Vessel) 

Mississippi Canyon 809, Proposed Location HH is located in a water depth of approximately 3635 feet. 

Proposed Location HH will be positioned 303’ east (down-thrown) of a minor seafloor fault with less than 5’ of 

offset and 521’ east (down-thrown) of the next closest minor fault with less than 5 feet of offset. MC 809, 

Proposed Location HH is not expected to penetrate any faults. There is no other evidence of seafloor or 

near-surface faulting within 2000’ of Proposed Location HH. MC 809, Proposed Location HH will not disturb 

any high-density areas of benthic communities. 

The following table consisting of 2 targets is a listing of marine avoidance zones identified within 2000’ of MC 

809, Proposed Location HH: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc HH

Direction from 

Prop Loc HH

5500 100’ 953,471 10,224,156 1238’ Northwest

5498 100’ 953,790 10,224,977 1925 North

There are no barrels identified within 2000’ of MC 809, Proposed Location HH. 

Proposed Location HH will be 675’ southwest of Shell’s MC 765 to 809 Ursa TLP flowline and umbilicals.

Conclusion: 

Based on high-resolution surveys consisting of AUV Side Scan Sonar, and Sub-bottom Profiler, Air Gun data, 

Sparker, frequency enhanced 3-D Seismic, Enhanced Surface renderings (ESR’s), ESR’s with amplitudes 

applied, MC 809, Proposed Location HH appears suitable for the planned activity. 

Site Assessment, MC 809, Proposed Location II: 

Mississippi Canyon 809, Proposed Location II is located in a water depth of approximately 3640 feet. 

Proposed Location II will be positioned 687’east-southeast (down-thrown) and 933’ north-northwest (upthrown) of minor seafloor faults with less than 5’ of offset, and 1500’ east (up-thrown) of another seafloor 

fault with 5 to 20’ of offset. Proposed Location II will not penetrate any faults. 

Page 29 Public Information Copy
The stratigraphy at the site of MC 809, Proposed Location II consists of: 

 Unit 1 (Seafloor – 494’ BML) 494’ of hemipelagic mud with muddy MTD’s in lower part of Unit 1

Unit 2 (494’ – 1340’ BML) 846’ total, 376’ of mud, 80’ of MTD’s (870’ – 950’ BML), 390’ of 

 potential laminated levee sands (950’ – 1340’ BML)

Unit 3 (1340’ – 2024’ BML) 684’ total, 360’ of channel sands (1340’ – 1700’ BML), Canyon Base 

 1700’ BML, 135’ of sand-prone Blue Unit (1700’ – 1835’ BML), 189’ of muddy sediments

Unit 4 (2024’ – 2873’ BML) 849’ of mud-prone sediments with minor thin sand intervals in top 

 part of Unit 4 

Unit 5 (2873’ – 4296’ BML) 1423’ of mud interbedded with sand in upper part of Unit 5

 

Shallow Water Flow Potential: 

 Low - Seafloor – 494’ BML

 Moderately Low – 494’ – 1340’ BML

 Moderate to High – 1340’ – 2024’ BML

 Moderately Low – 2024’ – 4296’ BML

Shallow Gas Potential 

 Low – Seafloor – 494’ BML

 Moderately Low – 494’ – 2873’ BML

 Moderate – 2873’ – 4296’ BML

Buried amplitudes are identified within the following units: 

Unit 2 (494’-1340’ BML) 462’ to South/southwest

 Unit 3 (1340’-2024’ BML) 615’ to South

Unit 5 (2873’-4296’ BML) 467’ to Southwest

Unit 6 (below 4296’ BML) 415’ to South/Southwest

Benthic/Anchor Assessment, MC 809, Proposed Location II (no anchors – DP Vessel) 

Mississippi Canyon 809, Proposed Location II is located in a water depth of approximately 3640 feet. 

Proposed Location II will be positioned 687’east-southeast (down-thrown) and 933’ north-northwest (upthrown) of minor seafloor faults with less than 5’ of offset, and 1500’ east (up-thrown) of another seafloor 

fault with 5 to 20’ of offset. Proposed Location II will not penetrate any faults. There is no other evidence 

of seafloor or near-surface faulting within 2000’ of Proposed Location II. MC 809, Proposed Location II will 

not disturb any high-density areas of benthic communities. 

The following table consisting of 1 target is a listing of marine avoidance zones identified within 2000’ of MC 

809, Proposed Location II: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc II

Direction from 

Prop Loc II

5500 100 953471 10224156 1702’ Northwest

There are no barrels identified within 2000’ of MC 809, Proposed Location II. 

Proposed Location II will be 725’ southwest of Shell’s MC 765 to 809 Ursa TLP flowline and umbilicals. 

Conclusion: 

Based on high-resolution surveys consisting of AUV Side Scan Sonar, and Sub-bottom Profiler, Air Gun data, 

Sparker, frequency enhanced 3-D Seismic, Enhanced Surface renderings (ESR’s), ESR’s with amplitudes 

applied, MC 809, Proposed Location II appears suitable for the planned activity. 

Page 30 Public Information Copy
Site Assessment, MC 809, Proposed Location JJ: 

Mississippi Canyon 809, Proposed Location JJ is located in a water depth of approximately 3615 feet. 

Proposed Location JJ will be positioned over 310’ west (up-thrown), 415’ southeast (down-thrown) and 598’

east (down-thrown) of minor seafloor faults with less than 5’ of offset, and 1100 southwest (up-thrown) of a 

buried (15’) fault. Proposed Location JJ will not penetrate any faults. 

The stratigraphy at the site of MC 809, Proposed Location JJ consists of: 

 Unit 1 (Seafloor – 504’ BML) 504’ of hemipelagic mud with muddy MTD’s in lower part of Unit 1

Unit 2 (504’ – 1500’ BML) 996’ total, 391’ of mud, 50’ of MTD’s (895’ – 945’ BML), 555’ of 

 potential laminated levee sands (945’ – 1500’ BML)

Unit 3 (1500’ – 2031’ BML) 531’ total, 235’ of channel sands (1500’ – 1735’ BML), Canyon Base 

 1735’ BML, 125’ of sand-prone Blue Unit (1735’ – 1860’ BML), 171’ of muddy sediments

Unit 4 (2031’ – 2936’ BML) 905’ of mud-prone sediments with minor thin sand intervals in top 

 part of Unit 4 

Unit 5 (2936’ – 4382’ BML) 1446’ of mud interbedded with sand in upper part of Unit 5 

Shallow Water Flow Potential: 

 Low - Seafloor – 504’ BML

 Moderately Low – 504’ – 1500’ BML

 Moderate to High – 1500’ – 2031’ BML

 Moderately Low – 2031 – 4382’ BML

Shallow Gas Potential 

 Low – Seafloor – 504’ BML

 Moderately Low – 504’ – 2936’ BML

 Moderate – 2936’ – 4382’ BML

Buried amplitudes are identified within the following units: 

Unit 2 (504’-1500’ BML) 478’ to Southwest

Unit 3 (1500’-2031’ BML) 1155’ to South

Unit 5 (2936’-4382’ BML) 432’ to East/Northeast

Unit 6 (below 4382’ BML) 1153’ to South

Benthic/Anchor Assessment, MC 809, Proposed Location JJ (no anchors – DP Vessel) 

Mississippi Canyon 809, Proposed Location JJ is located in a water depth of approximately 3615 feet. 

Proposed Location JJ will be positioned over 310’ west (up-thrown), 415’ southeast (down-thrown) and 598’

east (down-thrown) of minor seafloor faults with less than 5’ of offset, and 1100 southwest (up-thrown) of a 

buried (15’) fault. Proposed Location JJ will not penetrate any faults. There is no other evidence of seafloor 

or near-surface faulting within 2000’ of Proposed Location JJ. MC 809, Proposed Location JJ will not disturb 

any high-density areas of benthic communities. 

The following table consisting of 3 targets is a listing of marine avoidance zones identified within 2000’ of MC

809, Proposed Location JJ: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc JJ

Direction from 

Prop Loc JJ

5500 100 953471 10224156 480’ North

5498 100 953790 10224977 1352’ Northeast

5471 100 952040 10224960 1873’ Northwest

There are no barrels identified within 2000’ of MC 809, Proposed Location JJ. 

Page 31 Public Information Copy
Proposed Location JJ will be 875’ southwest of Shell’s MC 765 to 809 Ursa TLP flowline and umbilicals. 

Conclusion: 

Based on high-resolution surveys consisting of AUV Side Scan Sonar, and Sub-bottom Profiler, Air Gun data, 

Sparker, frequency enhanced 3-D Seismic, Enhanced Surface renderings (ESR’s), ESR’s with amplitudes 

applied, MC 809, Proposed Location JJ appears suitable for the planned activity. 

Site Assessment, MC 809, Proposed Location KK: 

Mississippi Canyon 809, Proposed Location KK is located in a water depth of approximately 3637’ feet. 

Proposed Location KK will be positioned 300’ east (down-thrown) and 670’ west (up-thrown) 1000’ east (upthrown) of the nearest seafloor faults with less than 5’ of offset, and 850 southwest (up-thrown) of a buried 

(15’) fault. Proposed Location KK will not penetrate any faults. 

The stratigraphy at the site of MC 809, Proposed Location KK consists of: 

 Unit 1 (Seafloor – 504’ BML) 504’ of hemipelagic mud with muddy MTD’s in lower part of Unit 1

 Unit 2 (504’ – 1464’ BML) 960’ total, 382’ of mud, 79’ of MTD’s (861’ – 940’ BML), 450’ of 

 potential laminated levee sands (940’ – 1464’ BML)

 Unit 3 (1464’ – 2017’ BML) 553’ total, 270’ of channel sands (1464’ – 1734’ BML), Canyon Base

 1734’ BML, 283’ of sand-prone Blue Unit (1734’ – 2017’ BML) 

 Unit 4 (2017’ – 2970’ BML) 953’ of mud-prone sediments with minor thin sand intervals in top 

 part of Unit (2017’ – 2348’ BML)

 Unit 5 (2970’ – 4478’ BML) 1508’ of mud interbedded with sand (3147’ – 3662’ BML)

Shallow Water Flow Potential: 

 Low - Seafloor – 504’ BML

 Moderately Low – 504’ – 1464’ BML

 Moderate to High – 1464’ – 2017’ BML

 Moderately Low – 2017’ – 4478’ BML

Shallow Gas Potential 

 Low – Seafloor – 504’ BML

 Moderately Low – 504’ – 2970’ BML

 Moderate – 2970’ – 4478’ BML 

Buried amplitudes are identified within the following units: 

Unit 2 (504’-1464’ BML) 922’ to West

Unit 3 (1464’-2017’ BML) 1141’ to Northeast

Unit 5 (2970’-4478’ BML) 745’ to Southeast

Unit 6 (below 4478’ BML) 1982’ to South/southeast

Benthic/Anchor Assessment, MC 809, Proposed Location KK (no anchors – DP Vessel) 

Mississippi Canyon 809, Proposed Location D is located in a water depth of approximately 3637 feet. 

Proposed Location KK will be positioned 300’ east (down-thrown) and 670’ west (up-thrown) 1000’ east (upthrown) of the nearest seafloor faults with less than 5’ of offset, and 850 southwest (up-thrown) of a buried 

(15’) fault. Proposed Location KK will not penetrate any faults. There is no other evidence of seafloor or 

near-surface faulting within 2000’ of Proposed Location KK. MC 809, Proposed Location KK will not disturb 

any high-density areas of benthic communities. 

The following table consisting of 6 targets is a listing of marine avoidance zones identified within 2000’ of MC 

809, Proposed Location KK: 

Page 32 Public Information Copy
Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc KK

Direction from 

Prop Loc KK

5500 100 953471 10224156 384’ Southeast 

5498 100 953790 10224977 684’ Northeast 

5471 100 952040 10224960 1341’ Northwest

5495 100 954144 10225949 1677’ Northeast 

U8 100 954139 10225962 1686’ Northeast 

M172 100 954453 10225866 1788’ Northeast 

There are no barrels identified within 2000’ of MC 809, Proposed Location KK.

Proposed Location KK will be 600’ southwest of Shell’s MC 765 to 809 Ursa TLP flowline and umbilicals. 

Conclusion: 

Based on high-resolution surveys consisting of AUV Side Scan Sonar, and Sub-bottom Profiler, Air Gun data, 

Sparker, frequency enhanced 3-D Seismic, Enhanced Surface renderings (ESR’s), ESR’s with amplitudes 

applied, MC 809, Proposed Location KK appears suitable for the planned activity. 

Site Assessment, MC 809, Proposed Location LL: 

Mississippi Canyon 809, Proposed Location LL is located in a water depth of approximately 3645 feet. 

Proposed Location LL will be positioned over 510’ east (down-thrown) and 440’ west (up-thrown) of minor 

seafloor faults with less than 5’ of offset. Proposed Location E will not penetrate any faults. 

The stratigraphy at the site of MC 809, Proposed Location LL consists of: 

 Unit 1 (Seafloor – 482’ BML) 482’ of hemipelagic mud with muddy MTD’s in lower part of Unit 1

Unit 2 (482’ – 1395’ BML) 913’ total, 443’ of mud, 470’ of potential laminated levee sands (542’ - 

1395’ BML)

Unit 3 (1395’ – 2037’ BML) 642’ total, 270’ of channel sands (1395’ – 1665’ BML), Canyon Base 

 1665’ BML, 200’ of sand-prone Blue Unit (1665’ – 1865’ BML), 172’ of muddy sediments

Unit 4 (2037’ – 2987’ BML) 950’ of mud-prone sediments with minor thin sand intervals in top 

 part of Unit 4 

Unit 5 (2987’ – 4541’ BML) 1554’ of mud interbedded with sand in upper part of Unit 5 

Shallow Water Flow Potential: 

 Low - Seafloor – 482’ BML

 Moderately Low – 482’ – 1395’ BML

 Moderate to High – 1395’ – 2037’ BML

 Moderately Low – 2037’ – 4541’ BML

Shallow Gas Potential 

 Low – Seafloor – 482’ BML

 Moderately Low – 482’ – 1395’ BML

 Moderate – 1395’ – 2037’ BML

 Moderately Low – 2037’ – 2987’

 Moderate – 2987’ – 4541’

Buried amplitudes are identified within the following units: 

Unit 2 (482’-1395’ BML) 960’ to Southwest

Unit 3 (1395’-2037’ BML) 960’ to Southwest

Unit 5 (2987’-4541’ BML) 1140’ to West/southwest

Page 33 Public Information Copy
Benthic/Anchor Assessment, MC 809, Proposed Location LL (no anchors – DP Vessel) 

Mississippi Canyon 809, Proposed Location LL is located in a water depth of approximately 3645 feet. 

Proposed Location LL will be positioned over 510’ east (down-thrown) and 440’ west (up-thrown) of minor 

seafloor faults with less than 5’ of offset. Proposed Location E will not penetrate any faults. There is no 

other evidence of seafloor or near-surface faulting within 2000’ of Proposed Location LL. MC 809, Proposed 

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

The following table consisting of 6 targets is a listing of marine avoidance zones identified within 2000’ of MC 

809, Proposed Location LL: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc LL

Direction from 

Prop Loc LL

5471 100 952040 10224960 851’ Southwest

5498 100 953790 10224977 1206’ Southeast

U8 100 954139 10225962 1512’ Northeast

5495 100 954144 10225949 1512’ Northeast

5500 100 953471 10224156 1545’ Northeast

M172 100 954453 10225866 1791’ Southeast 

There are 3 barrels identified within 2000’ of MC 809, Proposed Location LL. 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc LL

Direction from 

Prop Loc LL

5611 50 952136 10226262 952’ Northwest 

5610 50 951635 10226234 1297’ Northwest

5609 50 952519 10227117 1631’ Northwest

Proposed Location LL will be 975’ west of Shell’s MC 765 to 809 Ursa TLP flowline and umbilicals. 

Conclusion: 

Based on high-resolution surveys consisting of AUV Side Scan Sonar, and Sub-bottom Profiler, Air Gun data, 

Sparker, frequency enhanced 3-D Seismic, Enhanced Surface renderings (ESR’s), ESR’s with amplitudes 

applied, MC 809, Proposed Location LL appears suitable for the planned activity. 

Site Assessment, MC 809, Proposed Location MM: 

Mississippi Canyon 809, Proposed Location MM is located in a water depth of approximately 3645 feet. 

Proposed Location MM will be positioned over 440’ east (down-thrown) and 840’ north (up-thrown) of minor 

seafloor faults with less than 5’ of offset. Proposed Location MM will not penetrate any faults. 

The stratigraphy at the site of MC 809, Proposed Location MM consists of: 

 Unit 1 (Seafloor – 479’ BML) 479’ of hemipelagic mud with muddy MTD’s in lower part of Unit 1

Unit 2 (479’ – 1435’ BML) 956’ total, 436’ of mud, 520’ of potential laminated levee sands (915’ - 

 1435’ BML)

Unit 3 (1435’ – 2030’ BML) 595’ total, 415’ of channel sands (1435’ - 1850’ BML, Canyon Base 

 1850’ BML, 180’ sand-prone Blue Unit (1850’ – 2030’ BML)

Unit 4 (2030’ – 3001’ BML) 971’ of mud-prone sediments with minor thin sand intervals in top 

 part of Unit 4 

Unit 5 (3001’ – 4589’ BML) 1588’ of mud interbedded with sand in upper part of Unit 5

Page 34 Public Information Copy
Shallow Water Flow Potential: 

 Low - Seafloor – 479’ BML

 Moderately Low – 479’ – 1435’ BML

Moderate – 1435’ – 2030’ BML

 Moderately Low – 2030’ – 4589’ BML

Shallow Gas Potential 

 Low – Seafloor – 479’ BML

 Moderately Low – 479’ – 3001’ BML

 Moderate – 3001’ – 4589’ BML

Buried amplitudes are identified within the following units: 

 Unit 2 (479’-1435’ BML) 1236’ to Northwest

Unit 3 (1435’-2030’ BML) 429’ to Southeast

Unit 5 (3001’-4589’ BML) 1369’ to Southwest

Benthic/Anchor Assessment, MC 809, Proposed Location MM (no anchors – DP Vessel) 

Mississippi Canyon 809, Proposed Location MM is located in a water depth of approximately 3645 feet. 

Proposed Location MM will be positioned over 440’ east (down-thrown) and 840’ north (up-thrown) of minor 

seafloor faults with less than 5’ of offset. Proposed Location MM will not penetrate any faults. There is no 

other evidence of seafloor or near-surface faulting within 2000’ of Proposed Location MM. MC 809, Proposed 

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

The following table consisting of 6 targets is a listing of marine avoidance zones identified within 2000’ of MC 

809, Proposed Location MM: 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc MM

Direction from 

Prop Loc MM

5471 100 952040 10224960 1282’ Southwest

U8 100 954139 10225962 1564’ Southeast

5495 100 954144 10225949 1570’ Southeast 

5498 100 953790 10224977 1663’ Southeast 

5493 100 954231 10226858 1805’ Northeast 

M172 100 954453 10225866 1887’ Southeast 

There are 5 barrels identified within 2000’ of MC 809, Proposed Location MM. 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc MM

Direction from 

Prop Loc MM

5611 50 952136 10226262 469’ Northwest 

5610 50 951635 10226234 955’ Northwest 

5609 50 952519 10227117 998’ Northwest 

5613 50 953471 10227484 1627’ Northwest 

5608 50 950690 10226483 1927’ Southeast 

Page 35 Public Information Copy
There are 70 barrels identified within 2000’ of MC 809, Proposed Location MM. 

Avoidance 

Zone Number Avoidance 

Central X

Coordinate

Central Y 

Coordinate

Distance from 

Prop Loc MM

Direction from 

Prop Loc MM

5614 50 954176 10227673 2224’ Northeast 

5568 50 950757 10227532 2308’ Northwest 

5569 50 951360 10228102 2328’ Northwest 

5570 50 951443 10228299 2458’ Northwest 

5547 50 951183 10228162 2475’ Northwest 

5544 50 951229 10228201 2482’ Northwest 

5545 50 951211 10228199 2490’ Northwest 

5571 50 951555 10228391 2492’ Northwest 

5539 50 951413 10228328 2498’ Northwest 

5554 50 950989 10228053 2505’ Northwest 

5543 50 951241 10228236 2505’ Northwest 

5623 50 951575 10228415 2506’ Northwest 

5542 50 951244 10228242 2508’ Northwest 

5540 50 951373 10228320 2510’ Northwest 

5624 50 951566 10228416 2510’ Northwest 

5541 50 951288 10228272 2511’ Northwest 

5538 50 951431 10228364 2522’ Northwest 

5552 50 951035 10228128 2535’ Northwest 

5556 50 950871 10228011 2550’ Northwest 

5550 50 951068 10228179 2556’ Northwest 

5559 50 950771 10227926 2558’ Northwest 

5551 50 951045 10228168 2560’ Northwest 

5574 50 952169 10228648 2561’ Northwest 

5606 50 950108 10226792 2564’ Northwest 

5553 50 950957 10228110 2569’ Northwest 

5549 50 951047 10228198 2583’ Northwest 

5560 50 950741 10227953 2598’ Northwest 

5558 50 950748 10227971 2606’ Northwest 

5557 50 950759 10227992 2613’ Northwest 

5573 50 951935 10228661 2621’ Northwest 

5546 50 951184 10228338 2622’ Northwest 

5565 50 950654 10227901 2625’ Northwest 

5414 50 950646 10227895 2627’ Northwest 

5413 50 950634 10227890 2632’ Northwest 

5566 50 950638 10227895 2633’ Northwest 

5562 50 950681 10227954 2641’ Northwest 

5572 50 951908 10228681 2647’ Northwest 

5537 50 951561 10228566 2650’ Northwest 

5548 50 951048 10228282 2651’ Northwest 

5607 50 952764 10228771 2656’ Northwest 

5555 50 950804 10228100 2661’ Northeast 

5561 50 950682 10228000 2673’ Northwest 

5563 50 950514 10227852 2698’ Northwest 

5567 50 950578 10227927 2698’ Northwest 

5564 50 950549 10227895 2699’ Northwest 

5575 50 952098 10228776 2699’ Northwest 

5531 50 950652 10228042 2724’ Northwest 

5576 50 952157 10228844 2756’ Northwest 

5580 50 952399 10228880 2765’ Northwest 

5410 50 950331 10227773 2793’ Northwest 

Page 36 Public Information Copy
5579 50 952344 10228912 2801’ Northwest 

5577 50 952278 10228906 2802’ Northwest 

5536 50 952039 10228871 2803’ Northwest 

5412 50 950428 10227931 2814’ Northwest 

5411 50 950332 10227863 2846’ Northwest 

5408 50 950243 10227751 2852’ Northwest 

5535 50 952074 10228928 2853’ Northwest 

5409 50 950273 10227806 2859’ Northwest 

5578 50 952275 10228965 2861’ Northwest 

5581 50 952445 10228997 2879’ Northwest 

5406 50 950183 10227729 2889’ Northwest 

5407 50 950222 10227831 2915’ Northwest 

5402 50 950054 10227603 2931’ Northwest 

5405 50 950118 10227713 2934’ Northwest 

5404 50 950117 10227719 2938’ Northwest 

5582 50 952457 10229065 2947’ Northwest 

5584 50 952512 10229073 2953’ Northwest 

5585 50 952555 10229077 2956’ Northwest 

5403 50 950057 10227695 2976’ Northwest 

5583 50 952474 10229117 2998’ Northwest 

Proposed Location MM will be 1050’ west of Shell’s MC 765 to 809 Ursa TLP flowline and umbilicals. 

Conclusion: 

Based on high-resolution surveys consisting of AUV Side Scan Sonar, and Sub-bottom Profiler, Air Gun data, 

Sparker, frequency enhanced 3-D Seismic, Enhanced Surface renderings (ESR’s), ESR’s with amplitudes 

applied, MC 809, Proposed Location MM appears suitable for the planned activity. 

B. Topographic Features Map

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

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

C. Topographic Features Statement (Shunting)

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

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

G04 is not applicable. 

D. Live Bottoms (Pinnacle Trend) Map

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

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

E. Live Bottoms (Low Relief) Map

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

map is required per NTL No. 2008-G04. 

F. Potentially Sensitive Biological Features

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

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

Page 37 Public Information Copy
G. Remotely Operated Vehicle (ROV) Monitoring Plan

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

Mississippi Canyon Block 809 is located in Grid 13, which is considered an area that does have adequate ROV 

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

2008-G06. 

H. Threatened and Endangered Species Information

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

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

or adversely modify its designated critical habitat. 

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

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

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

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

this plan. 

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

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

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

area and along the northern Gulf coast: 

Common Name Scientific Name T/E Status

Hawksbill Turtle Eretmochelys imbricata E

Green Turtle Chelonia mydas T/E

Kemp's Ridley Turtle Lepidochelys kempii E

Leatherback Turtle Dermochelys coriacea E

Loggerhead Turtle Caretta caretta T

Table 6.6 – Threatened and Endangered Sea Turtles 

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

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

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

habitat for these species has been designated in the Gulf of Mexico. 

Common Name Scientific Name T/E Status

Atlantic Spotted Dolphin Stenella frontalis

Blainville's Beaked Whale Mesoplodon densirostris

Blue Whale Balaenoptera musculus E

Bottlenose Dolphin Tursiops truncatus

Bryde's Whale Balaenoptera edeni

Clymene Dolphin Stenella clymene

Cuvier's Beaked Whale Ziphius cavirostris

Dwarf Sperm Whale Kogia simus

False Killer Whale Pseudorca crassidens

Fin Whale Balaenoptera physalus E

Fraser's Dolphin Lagenodelphis hosei

Gervais' Beaked Whale Mesoplodon europaeus

Page 38 Public Information Copy
Humpback Whale Megaptera novaeangliae E

Killer Whale Orcinus orca

Melon-headed Whale Peponocephala electra

Minke Whale Balaenoptera acutorostrata

North Atlantic Right Whale Eubalaena glacialis E

Pantropical Spotted Dolphin Stenella attenuata

Pygmy Killer Whale Feresa attenuata

Pygmy Sperm Whale Kogia breviceps

Risso's Dolphin Grampus griseus

Rough-toothed Dolphin Steno bredanensis

Sei Whale Balaenoptera borealis E

Short-finned Pilot Whale Globicephala macrorhynchus

Sowerby's Beaked Whale Mesoplodon bidens

Sperm Whale Physeter macrocephalus E

Spinner Dolphin (Long-snouted) Stenella longirostris

Striped Dolphin Stenella coeruleoalba

Florida manatee Trichechus manatus E

Table 6.7 – Threatened and Endangered Marine Mammals 

The blue, fin, humpback, North Atlantic right and sei whales are rare or extralimital in the Gulf of Mexico and 

are unlikely to be present in the lease area. The Environmental Impact Analysis found in Section 18 

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

I. Archaeological Report

The following reports were used in this analysis: 

Archaeological and Hazard Report, Blocks 808, 809, 852, 853 and Vicinity, Mississippi Canyon Area, Project 

Nom 083986-084109, C&C Technologies, dated February, 2009. AUV (Autonomous Underwater Vehicle) data 

consisting of side-scan sonar and sub-bottom profiler. 

Archaeological Analysis

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

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

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

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

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

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

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

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

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

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

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

J. Air and Water Quality Information

Mississippi Canyon Block 809 is located 55 miles from the nearest shoreline. Drilling operations will produce 

air pollutant emissions, but as provided in the Air Emissions Spreadsheet (see Section 8 of this Plan), these 

operations are below the exemption levels. 

Page 39 Public Information Copy
These drilling operations will result in the discharge of authorized effluents under the EPA Region VI General 

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

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

K. Socioeconomic Information

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

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

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

within the State of Florida for these operations. 

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

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

L. Waste Barrels Report

Shell is including the “Waste Barrel Avoidance and Release Response in the Mississippi Rev 2” dated 

October 20, 2010 in this section of the plan.

Page 40 Public Information Copy
Attachment 6A – Enhanced Seafloor Rendering Map 

Page 41 Public Information Copy
Attachment 6B – Enhanced Seafloor Rendering Map 

Page 42 Public Information Copy
Attachment 6C – Enhanced Seafloor Rendering Map 

Page 43 Public Information Copy
Attachment 6D – Enhanced Seafloor Rendering Map 

Page 44 Public Information Copy
Attachment 6E – Enhanced Seafloor Rendering Map 

Page 45 Public Information Copy
Attachment 6F – Enhanced Seafloor Rendering Map

Page 46 Public Information Copy
SECTION 7: WASTE AND DISCHARGE INFORMATION

A. Projected Ocean Discharges 

Type of Waste and Composition Composition Projected Amount/Well Discharge rate/day Discharge Method Answer yes or no

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

EXAMPLE: Cuttings wetted with ynthetic based fluid 

Cuttings generated while using synthetic 

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

Water-based drilling fluid barite, additives, mud 5,760,000/well 40,000 bbls/day/well

Seafloor discharge prior to marine riser 

installation No

Cuttings wetted with water-based fluid

Cuttings coated with water based drilling 

mud 164,592 bbls/well 1143 bbls/day/well

Seafloor discharge prior to marine riser 

installation No

Cuttings wetted with synthetic-based fluid 

Cuttings generated while using synthetic 

based drilling fluid 10,224 bbls/well 71bbls/day/well Cuttings chute below MSL No

Synthetic based drilling fluid adhering to washed drill 

cuttings

Synthetic based drilling fluid adhering to 

washed drill cuttings 2880 bbls/well 20 bbls/day/well Cuttings chute below MSL 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 216,000 bbls 300bbls/day/well

Ground to less than 25 mm mesh size 

and discharge overboard No

Sanitary waste (toilet water) treated sanitary waste 17280 bbls 24bbls/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 4536 bbls 6.3bbls/day

Drained overboard through deck 

scuppers No

Will you conduct well treatment, completion, or workover? 

Well Treatment Fluids NA NA NA NA NA

Well Completion Fuids NA NA NA NA NA

Well Clean Up Fluids NA NA NA NA NA

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

Desalinization unit discharge Rejected water from watermaker unit 21600 30bbls/day Discharged overboard below waterline No

Blowout prevent fluid Water based 2808 bbls/well 19.5 bbls/day/well Disharge at seafloor No

Ballast water Uncontaminated seawater 4320 bbls 6bbls/day Discharged overboard No

Bilge water

Bilge and drainage water will be treated to 

MARPOL standards (< 15ppm oil in water). 9360 bbls 13bbls/day

Bilge and drainage water will be treated 

to MARPOL standards (< 15ppm oil in 

water). No

Excess cement at seafloor Cement slurry

220320 bbls/well (assume 

planned 150% excess is 

discharged) 1530 bbls/well

Discharged at the seafloor during 

riserless drilling (32", 28" and 22") & any 

excess cement from cement jobs No

Fire water Treated seawater 8640 bbls 12bbls/day

Drained overboard through deck 

scuppers No

Cooling water Treated seawater 72,720,000 bbls 505,000 bbls/day Discharged overboard 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 ? GENERAL PERMIT GMG290103

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

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

Projected 

Downhole 

Projected generated waste Projected ocean discharges Disposal

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

Page 47 Public Information Copy
B. Projected Generated Wastes 

Solid and Liquid Wastes 

transportation 

Type of Waste Composition Transport Method Name/Location of Facility Amount Disposal Method

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

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

Synthetic-based drilling fluid or mud Used SBF and additives dedicated tanks on support vessels Halliburton - Fourchon, LA 5,000 bbls/well Recycled

Cuttings wetted with Synthetic-based fluid 

Drill cuttings from synthetic 

based interval. Cutting boxes Newpark Environmental, Ingleside, TX 150 bbls / well Recycled

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

Completion Brine NA NA NA NA NA

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

Produced sand NA NA NA NA NA

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

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

Omega Waste Management, W. 

Patterson, LA or ARC, New Iberia, LA 22,700 lbs/well Recycled

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

Republic/BFI landfill, Sorrento, LA or 

the parish landfill, Avondale, LA 11,400 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

EP: Deep Troika TB001

C. Modeling Report

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

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

Page 48 Public Information Copy
SECTION 8: AIR EMISSIONS INFORMATION

A. Emissions Worksheet and Screening Questions 

Screening Questions for EP’s Yes No

Is any calculated Complex Total (CT) Emission amount (in tons) associated with 

your proposed exploration activities more than 90% of the amounts calculated 

using the following formulas: CT = 3400D2/3 for CO and CT 33.3D for the 

other air pollutants (where D distance to shore in miles)?

x

Do your emission calculations include any emission reduction measures or 

modified emission factors? X*

Are your proposed exploration activities located east of 87.5° W longitude? x

Do you expect to encounter H2S at concentrations greater than 20 parts per million 

(ppm)? x

Do you propose to flare or vent natural gas for more than 48 continuous hours

From any proposed well? x

Do you propose to burn produced hydrocarbon liquids? x

 

*Note: The following AQR is using fuel limitations and Shell will perform fuel monitoring for 

this project. 

 If you answer no to all of the above screening questions from the appropriate table, provide: 

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

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

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

do not need to include the entire set of worksheets. 

Air Pollutant

Plan Emission

Amounts 

(tons)

Calculated 

Exemption 

Amounts 

(tons)

Calculated

Complex Total 

Emission 

Amounts

(tons)

PM

SOx

NOx

VOC

CO

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

B. Worksheets 

See Attachment 8A. 

Page 49 Public Information Copy
Attachment 8A – Air Quality Report

Fuel Limit Basis for Drillships and DP Semi-subs

jbm - 6/27/13

Purpose

Step 1 - Determine Typical Operating Loads

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

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

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

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

 

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

45% 40% 50%

45% 40% 50%

45% 40% 50%

45% 40% 50%

0% 0% 0%

0% 0% 0%

30% 27% 33%

Step 2 - Identify Corresponding Fuel Levels

Value

74615

33%

25,000

3.60

Step 3 - Other Vessel Fuel Loads

Value

50%

10,943

5,471

6,260

939

1.03

Additional Notes

Campaign Average Daily Fuel Use 

(gal/day)

Calculated Value - PTE fuel use * Proposed Operating Load. 

Crew Vessel

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

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

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

revised AQR calculations.

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

AQR conversion factor of 0.0483 gal/hp-hr.

Campaign Average Daily Fuel Use 

(gal/day)

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

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

Total Vessel Activity

CY2014-2019 Fuel Limits MMGals Sum of (vessel daily fuel use * corresponding campaign days)

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

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

(25 nm), traveling at economical speeds. 

Offshore Support Vessels

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

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

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

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

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

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

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

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

considered representative for the full campaign. 

% Load

Engine

1

2

3

4

5

6

Proposed Operating Load See Step 1 above.

Campaign Average Daily Fuel Use 

(gal/day)

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

nearest thousand (for additional conservatism).

Description Notes

CY2014-2019 Fuel Limits MMGals Calculated Value - Campaign Average Daily Fuel Use * Campaign Days 

Average 

Description Notes

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

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

Page 50 Public Information Copy
COMPANY Shell Offshore Inc.

AREA Mississippi Canyon

BLOCK 809

LEASE G-05868

PLATFORM MODU

WELL 6 wells (HH, II, JJ, KK, LL & MM)

COMPANY 

CONTACT Jeff McMenis

TELEPHONE NO. 504-425-6021

REMARKS Mercury_AQR_EP_DP MODU_062713.xlsx

Page 51 Public Information Copy
Fuel Usage Conversion 

Factors

Natural Gas 

Turbines

Natural 

Gas 

Engines

Diesel 

Recip. 

Engine

REF. DATE

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

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

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

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

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

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

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

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

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

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

14-3

7/98

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

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

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

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

Glycol Dehydrator Vent lbs/mmscf 6.6 La. DEQ 1991

Gas Venting lbs/scf 0.0034

Sulphur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.05 % weight

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

maximum sulfur, effective June 1, 2007.

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

Page 52 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc. Mississippi Canyon 809 G-05868 MODU 6 w ells (HH, II, JJ, KK, LL & MM) Jeff McMenis 504-425-6021 Mercury_AQR_EP_DP MODU_062713.xlsx

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

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS P M SOx NOx VOC CO P M SOx NOx VOC CO

MODU Drilling PRIME MOVER>600hp diesel 10728 518 24 144 7.56 4.34 259.93 7.80 56.71

DP Drillship or DP Semi PRIME MOVER>600hp diesel 10728 518 24 144 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 144 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 144 7.56 4.34 259.93 7.80 56.71

PRIME MOVER>600hp diesel 10728 518 24 144 37.55 135.22 375.48 3.58 93.87

PRIME MOVER>600hp diesel 10728 518 24 144 23.63 4.34 330.82 26.47 71.60

Energency Generator>600hp diesel 2547 123 1 144 1.80 1.03 61.71 1.85 13.46

Emergency Air Compressor< 600hp diesel 26 1 1 144 0.02 0.01 0.63 0.02 0.14

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

Supply Vessel>600hp diesel (general support) 9440 456 5471 24 144 6.65 3.82 228.72 6.86 49.90 5.75 3.30 197.62 5.93 43.12

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

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

Crew Vessel>600hp diesel 5400 261 939 24 144 3.81 2.18 130.84 3.93 28.55 0.99 0.57 33.91 1.02 7.40

MISC. BPD SCF/HR COUNT

TANKDRILLING OIL BURN

WELL TEST GAS FLARE

2014-2019 YEAR TOTAL 117.01 171.57 2625.36 87.61 584.17 33.80 19.38 1161.92 34.86 253.51

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 1831.50 1831.50 1831.50 1831.50 49172.32

55.0

25000 26.27 15.06 902.95 27.09 197.01

Page 53 Public Information Copy
COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore 

Inc.

Mississippi 

Canyon 809 G-05868 MODU 6 wells (HH, II, JJ, KK, LL & MM)

Emitted Substance

Year

PM SOx NOx VOC CO

2014-2019 33.80 19.38 1161.92 34.86 253.51

Allowable 1831.50 1831.50 1831.50 1831.50 49172.32

Page 54 Public Information Copy
SECTION 9: OIL SPILL INFORMATION

A. Oil Spill Response Planning

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

Offshore Inc. (0689) in accordance with 30 CFR 254. Shell’s regional OSRP was approved by BSEE on April 

11, 2013. 

Spill Response sites are as follows: 

Primary Response Equipment Locations Preplanned Staging Location(s) 

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

MS; Pascagoula, MS

Venice, LA; Pacagouls, MS ; Mobile, AL

Table 9.1 – Response Equipment and Staging Areas 

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

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

Category Regional OSRP EP

Type of Activity Subsea Drilling Exploratory Drilling 

Facility Location (area/block) MC 391 MC 809

Facility Designation Subsea well 1◊ Subsea well K

Distance to Nearest Shoreline (miles) 70 55

Volume

Storage tanks (total)

Flowlines (on facility)

Pipelines

Uncontrolled blowout (volume per day)

Total Volume

N/A

N/A

N/A

416,414* BOPD

416,414 Bbls

N/A

N/A

N/A

425,000** BOPD

425,000 Bbls

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

diesel)

Crude oil Crude oil

API Gravity(s) 26o 28o

Table 9.2 - Worst Case Scenario Determination 

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

**24 hour rate (391,000 BOPD 30 day average) 

◊This well was reviewed and accepted by BOEM in Plan S-7444 (May 2011) and corrected by BSEE on July 10, 

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

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

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

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

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

threat of such a discharge, resulting from the activities proposed in our EP. 

Modeling:

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

Page 55 Public Information Copy
B. Oil Spill Response Discussion

1. Volume of the Worst Case Discharge 

Please refer to Section 2j and 9(iv) of this EP. 

2. Trajectory Analysis 

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

information in the BOEMRE Oil Spill Risk Analysis Model (OSRAM) for the Central and Western Gulf of 

Mexico available on the BOEMRE website using 30 day impact. Offshore areas along the trajectory 

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

probabilities are shown in Table 9.C.1. 

Area/Block OCS-G

Launch

Area Land Segment Contact %

Exploratory

MC 809 58

Galveston, TX 1 

Jefferson, TX 1 

Cameron, LA 3 

Vermillion, LA 2 

Iberia, LA 1 

Terrebonne, LA 3 

LaFourche, LA 3 

Jefferson, LA 1 

Plaquemines, LA 8 

St. Bernard, LA 1 

Okaloosa, FL 1 

Table 9.C.1 Probability of Land Segment Impact 

C. Resource Identification

The locations identified in Table 9.C.1 are the highest probable land segments to be impacted using 

the BOEMRE Oil Spill Risk Analysis Model (OSRAM). The environmental sensitivities are identified using 

the appropriate National Oceanic and Atmospheric Administration (NOAA) Environmental Sensitivity 

Index (ESI) maps for the given land segment. ESI maps provide a concise summary of coastal 

resources that are at risk if an oil spill occurs nearby. Examples of at-risk resources include biological 

resources (such as birds and shellfish beds), sensitive shorelines (such as marshes and tidal flats), and 

human-use resources (such as public beaches and parks). 

In the event an oil spill occurs, ESI maps can help responders meet one of the main response 

objectives: reducing the environmental consequences of the spill and the cleanup efforts. Additionally, 

ESI maps can be used by planners to identify vulnerable locations, establish protection priorities, and 

identify cleanup strategies. 

The following is a list of resources of special economic or environmental importance that potentially 

could be impacted by the Mississippi Canyon 809 WCD scenario. 

Page 56 Public Information Copy
Onshore/Nearshore: Plaquemines Parish has been identified as the most probable impacted Parish 

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

Worst Case Discharge. Plaquemines Parish has a total area of 2,429 square miles of which, 845 

square miles of it is land and 1,584 square miles is water. Plaquemines Parish includes two National 

Wildlife Refuges: Breton National Wildlife Refuge and Delta National Wildlife Refuge. This area is also 

a nesting ground for the brown pelican, an endangered species. Examples of Environmental Sensitivity 

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

and the legend are shown in Figures 9.C.1 through 9.C.5. 

Offshore: An offshore spill may require an Essential Fishing Habitat (EFH) Assessment. This assessment 

would include a description of the spill, analysis of the potential adverse effects on EFH and the 

managed species; conclusions regarding the effects on the EFH; and proposed mitigation, if applicable. 

Significant pre-planning of joint response efforts was undertaken in response to provisions of the 

National Contingency Plan (NCP). Area Contingency Plans (ACPs) were developed to provide a well 

coordinated response to oil discharges and other hazardous releases. The One Gulf Plan is specific to the 

Gulf of Mexico to advance the unity of policy and effort in each of the Gulf Coast ACPs. Strategies used 

for the response to an oil spill regarding protection of identified resources are detailed in the One Gulf 

Plan and relevant Gulf Coast ACP. 

D. Worst Case Discharge Response 

Shell will make every effort to respond to the MC809 Worst Case Discharge as effectively as possible. 

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

Mississippi Canyon Block 809

Calculations

(BBLS)

i. TOTAL WCD (based on 30 day average (per day)) 391,000

ii. Approximate loss of volume of oil to natural surface dispersion and evaporation 

base (approximate bbls per day)*

(7% Natural surface evaporation and dispersion in 24 hrs)

-27,300

APPROXIMATE TOTAL REMAINING ~363,700

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

account for surface dispersion and evaporation. 

Table 9.D.1 Oil Remaining After 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 

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

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

dispersant, shoreline protection, wildlife protection, and containment equipment. Following is a list of 

the contracted resources including de-rated recovery capacity, personnel, and estimated response 

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

designee may contact other service companies if the Unified Command deems such services necessary 

to the response efforts. 

Based on the anticipated worst case discharge scenario, Shell can be onsite with dedicated, contracted 

on water oil spill recovery equipment with adequate response capacity to contain and recover surface 

oil, and prevent land impact, within 33 hours (based on the equipment’s Estimated Daily Response 

Capacity (EDRC)). Shell will continue to ramp up additional on-water mechanical recovery resources 

as well as apply dispersants and in-situ burning as needed and as approved under the supervision of 

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

Subsea Control and Containment: Shell, as a founding member of the MWCC, will have access to 

the interim containment system (ICS) that can be rapidly deployed through the MWCC. The 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 809 

will be addressed in Shell’s NTL 2010-N10 submission at the time the APD is submitted. 

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

Mechanical Recovery (skimming): Response strategies include skimming utilizing available OSROs 

Oil Spill Response Vessels (OSRVs), Oil Spill Response Barges (OSRBs), ID Boats, and Quick Strike 

OSRVs. There is a combined de-rated recovery rate capability of approximately 848,000 barrels/day. 

Temporary storage associated with the identified skimming and temporary storage equipment equals 

approximately 861,000 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 and Storage Activation List 

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

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

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

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

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

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

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

Table 9.D.6 Aerial Surveillance Activation List

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

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

first 12 hour operating day of the response. These aerial systems could disperse approximately 7,704 

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

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from the Hercules C-130A within the first 12 hour operating day of the response could disperse 4,600 

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

Delivery System (ADDS) would be mobilized. The ADDS has a dispersant spray capability of 5,000 

gallons per sortie. 

 Table 9.D.7 Offshore Aerial Dispersant Activation List 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

used for approximately 8-12 burns before being replaced. Fire intensity and weather will be the main 

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

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

eliminate approximately 750 barrels. For planning purposes and based on the above assumptions, a 

single task force of four fire teams with the appropriate weather and safety conditions could complete 

four burns per day and remove up to ~12,000 bbls/day. In-situ burning nearshore and along 

shorelines may be a possible option based on several conditions and with appropriate approvals, as 

outlined in Section 19, In-situ Burn Plan (OSRP). In-situ burning along certain types of shorelines may 

be used to minimize physical damage where access is limited or if it is determined that 

mechanical/manual removal may cause a substantial negative impact on the environment. All safety 

considerations will be evaluated. In addition, Shell will assess the situation and can make notification 

within 48 hours of the initial spill to begin ramping up fire boom production through contracted 

OSRO(s). There are potential limitations that need to be assessed prior to ISB operations. Some 

limitations include atmospheric and sea conditions; oil weathering; air quality impacts; safety of 

response workers; and risk of secondary fires. 

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

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

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

boom on beach areas, or protection and sorbent boom on vegetated areas. Strategies would be based 

upon surveillance and real time trajectories provided by The Response Group that depict areas of 

potential impact given actual sea and weather conditions. Strategies from the New Orleans, Louisiana 

Area Contingency Plan, Unified Command would be consulted to ensure that environmental and 

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

Shell has access to shoreline response guides that depict the protection response modes applicable for 

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oil spill clean-up operations. Each response mode is schematically represented to show optimum 

deployment and operation of the equipment in areas of environmental concern. Supervisory personnel 

have the option to modify the deployment and operation of equipment allowing a more effective 

response to site-specific circumstances. 

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

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

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

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

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

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

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

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

advancements are continuing to be made to incorporate utilization of Koseq arms outfitted on barges, 

conversion of Platform Support Vessels for Oil Spill Response, and inclusion of nighttime spill detection 

radar to improve tracking capabilities (X-Band radar, Infrared sensing, etc.). In addition, new response 

technologies/techniques are continuing to be considered by Shell and the appropriate government 

organizations for incorporation into our planned response. Any additional response 

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

Command and USCG. 

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Figure 9.C.2 South Pass ESI Map 

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Figure 9.C.3 Garden Island Pass ESI Map 

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

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Figure 9.C.5 Main Pass ESI Map 

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

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

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

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

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

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

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

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

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Table 9.D.6 Aerial Surveillance Activation List 

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Table 9.D.7 Offshore Aerial Dispersant Activation List 

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

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

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

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

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

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

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

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

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

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SECTION 10: ENVIRONMENTAL MONITORING INFORMATION

A. Monitoring Systems 

A rig based Acoustic Doppler Current Profiler (ADCP) is used to continuously monitor the current beneath the 

rig. Metocean conditions such as sea states, wind speed, ocean currents, etc. will also be continuously monitored. 

Shell will comply with NTL 2009-G02. 

B. Incidental Takes 

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

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

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

from the BOEM/BSEE: 

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

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

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

Observer Program”

C. Flower Garden Banks National Marine Sanctuary 

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

Banks and Stetson Bank. 

SECTION 11: LEASE STIPULATIONS INFORMATION

Mississippi Canyon Block 808 and 809:

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

Section 6 of this plan for site specific archeological information. 

SECTION 12: ENVIRONMENTAL MITIGATION MEASURE INFORMATION

A. Impacts to Marine and coastal environments 

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

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

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

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

including Coastal Habitats and Protected Areas. 

B. Incidental Takes 

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

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

and operators from the BOEM/BSEE: 

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

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

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

Protected Species Observer Program”

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SECTION 13: RELATED FACILITIES AND OPERATIONS INFORMATION

Information regarding Related Facilities and Operations Information, transportation systems & produced liquid 

hydrocarbon transportation vessels are not included in this EP as such information is only necessary in the case of 

DOCDs. 

 

SECTION 14: SUPPORT VESSELS AND AIRCRAFT INFORMATION

A. General 

Type Maximum Fuel Tank 

Storage Capacity (Gals)

Maximum No. In Area at 

Any Time

Trip Frequency or 

Duration

Crew Boats 8,000 1 Twice per week

Offshore Support Vessels 120,000 2 Twice per week

Helicopter 760 1 Once per day

B. Diesel Oil Supply Vessels 

Size of Fuel Supply 

Vessel

Capacity of Fuel Supply 

Vessel

Frequency of Fuel 

Transfers

Route Fuel Supply Vessel Will 

Take

280 foot length 100,000 gals. 1 week 6 miles from Port Fourchon to 

the mouth of Bayou Lafourche, 

then to MC 809

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

Fourchon Port Fourchon, LA Existing

Boothville Heliport Boothville, LA Existing

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

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

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

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

B. Support Base Construction or Expansion 

This does not apply to this EP as Shell does not plan to construct a new onshore support base or expand 

an existing one to accommodate the activities proposed in this EP. 

C. Support Base Construction or Expansion Timetable 

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

land acquisition and construction or expansion is not applicable. 

D. Waste Disposal 

See Section 7, Tables 7A and 7B. 

E. Air emissions 

Not required by BOEM GOM. 

F. Unusual solid and liquid wastes 

Not required by BOEM GOM. 

SECTION 16: SULPHUR OPERATIONS INFORMATION

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

sulphur operations. 

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SECTION 17: COASTAL ZONE MANAGEMENT ACT (CZMA) INFORMATION

Louisiana Coastal Zone consistency was obtained in Plan N-6230 for these leases and is not required for 

supplemental plans. 

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SECTION 18: ENVIRONMENTAL IMPACT ANALYSIS (EIA)

SUPPLEMENTAL EXPLORATION PLAN 

Mississippi Canyon Block 809 (OCS-G 05868)

Offshore Louisiana 

July 2013 

Prepared for:

Shell Offshore Inc. 

P.O. Box 61933 

New Orleans, Louisiana 70161 

Telephone: (504) 425-6021 

Prepared by:

CSA Ocean Sciences Inc. 

8502 SW Kansas Avenue 

Stuart, Florida 34997 

Telephone: (772) 219-3000 

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Introduction 

Project Summary 

Shell Offshore Inc. (Shell) is submitting a Supplemental Exploration Plan (EP) for Mississippi 

Canyon Block 809 (MC 809) for six (6) exploration wells to be drilled using either a dynamically 

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

locations HH, II, JJ, KK, LL, and MM. All surface hole locations will be in MC 809. 

The lease area is 55 miles (89 km) from the nearest shoreline, 109 miles (175 km) from the 

onshore support base at Port Fourchon, Louisiana, and 80 miles (130 km) from the helicopter 

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

miles. Water depths at the wellsites range from approximately 3,615 to 3,645 ft (1,102 to 

1,111 m). The average time to drill and complete each well will be approximately 144 days. 

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

 Noble Don Taylor or a similar drillship; and 

 Noble Jim Day or a similar DP semisubmersible rig. 

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 Code of Federal Regulations 

(CFR) 550.212(o) and 550.227. The EIA is a project- and site-specific analysis of Shell’s planned 

activities under this EP. 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 Minerals 

Management Service (MMS) and Bureau of Ocean Energy Management, Regulation and 

Enforcement (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 Bureau of Safety and 

Environmental Enforcement (BSEE), the EIA will refer to the former BOEMRE as BOEM when 

addressing NTLs issued by BOEMRE or MMS. 

The EIA presents data, analyses, and conclusions to support BOEM reviews as required by the 

National Environmental Policy Act (NEPA) and other relevant federal laws, including the 

Endangered Species Act (ESA) and Marine Mammal Protection Act (MMPA). It also identifies 

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

The EIA is a project-specific analysis that focuses on the impacts of a specific plan. This EIA 

addresses the impact-producing factors (IPFs), resources, and impacts associated with the 

activities proposed in this EP. The EIA also analyzes the potential environmental impacts of the 

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

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The BOEM has performed numerous environmental evaluations of oil and gas activities on the 

Gulf of Mexico Outer Continental Shelf (OCS). Potential impacts were analyzed at a broader 

level in the Programmatic Environmental Impact Statements (EISs) 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; BOEM, 2012b). 

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

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

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

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

noise on threatened and endangered species, and other IPFs. The studies inform agency 

decision-making on lease offerings, mitigation measures and lease stipulations, operational 

requirements, and permit restrictions. This substantial body of work, which in part, forms the 

basis for the evaluation presented here, will allow the BOEM and other regulatory agencies to 

evaluate Shell’s EP and ensure that oil and gas exploration and development activities are 

performed in an environmentally sound manner, with minimal impacts on the environment. 

Shell has incorporated these comprehensive environmental analyses by reference and built on 

them with project- and site-specific analyses, where applicable. 

OCS Regulatory Framework 

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

MMS (2010), and post-Macondo regulatory changes were summarized in BOEM (2012b). Under 

the OCSLA, the U.S. Department of the Interior (USDOI) is responsible for the administration of 

mineral exploration and development of the OCS. Within the USDOI, the BOEM and BSEE are 

charged with the responsibility of managing and regulating the development of OCS oil and gas 

resources in accordance with the provisions of the OCSLA. The BSEE offshore regulations are in 

30 CFR Parts 250, 251, 252, 254, 256, 270, and 282. The BOEM offshore regulations are in 

30 CFR Parts 550, 551, 552, 556, 559, 560, 570, 580, 581, 582, and 585. 

In implementing its responsibilities under the OCSLA and NEPA, the BOEM consults numerous 

federal departments and agencies that have authority to govern and maintain ocean resources 

pursuant to other federal laws. Among these are the U.S. Coast Guard (USCG), 

U.S. Environmental Protection Agency (USEPA), U.S. Fish and Wildlife Service (USFWS), and the 

National Oceanic and Atmospheric Administration (NOAA) through the National Marine 

Fisheries Service (NMFS). Federal regulations establish consultation and coordination processes 

with federal, state, and local agencies (e.g., the ESA, MMPA, Coastal Zone Management Act of 

1972, and the Magnuson-Stevens Fishery Conservation and Management Act). 

NTLs are formal documents issued by the BOEM and BSEE that provide clarification, description, 

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

to this EIA. 

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

Impact Analysis (EIA). 

NTL Title Summary

2013-G02 Extension of Prior Notices to 

Lessees

Extends the effective date of NTL 2008-G04 (and two other NTLs) 

until the end of the 2013 calendar year.

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-

JOINTG01

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-

JOINTG01

Revisions to the List of OCS 

Blocks Requiring Archaeological 

Resource Surveys and Reports

Provides new information on which Outer Continental Shelf (OCS) 

blocks require archaeological surveys and reports and line spacing 

required in each block. This NTL augments NTL 2005-G07.

2010-N10

Statement of Compliance with 

Applicable Regulations and 

Evaluation of Information 

Demonstrating Adequate Spill 

Response and Well Containment 

Resources

Informs operators using subsea blowout preventers (BOPs) or 

surface BOPs on floating facilities that applications for well 

permits must include a statement signed by an authorized 

company official stating that the operator will conduct all activities 

in compliance with all applicable regulations, including the 

increased safety measures regulations (75 FR 63346). Informs 

operators that the BOEM will be evaluating whether each operator 

has submitted adequate information demonstrating that it has 

access to and can deploy containment resources to promptly 

respond to a blowout or other loss of well control.

2010-N06

Information Requirements for 

Exploration Plans, Development 

and Production Plans, and 

Development Operations 

Coordination Documents on the 

OCS

Rescinds the limitations set forth in NTL 2008-G04 regarding a 

blowout scenario and WCD scenario, and provides guidance 

regarding the information required in blowout scenario and 

WCD scenario descriptions.

2009-G40 Deepwater Benthic Communities

Guidance for avoiding and protecting high-density deepwater 

benthic communities (including chemosynthetic and deepwater 

coral communities) from damage caused by OCS oil and gas 

activities in water depths greater than 984 ft (300 m). Prescribes 

separation distances of 2,000 ft (610 m) from each mud and 

cuttings discharge location and 250 ft (76 m) from all other 

seafloor disturbances.

2009-G39 Biologically Sensitive Underwater 

Features and Areas

Guidance for avoiding and protecting biologically sensitive 

features and areas (i.e., topographic features, pinnacles, 

low-relief live bottom areas, and other potentially sensitive 

biological features) when conducting OCS operations in water 

depths less than 984 ft (300 m) in the Gulf of Mexico.

2008-G04

Information Requirements for 

Exploration Plans and 

Development Operations 

Coordination Documents

Guidance on the information requirements for OCS plans, 

including EIA requirements and information regarding compliance 

with the provisions of the Endangered Species Act and Marine 

Mammal Protection Act.

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NTL Title Summary

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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Oil Spill Prevention and Contingency Planning 

BSEE approved Shell’s Gulf of Mexico Regional Oil Spill Response Plan (OSRP) in April 2013. The 

OSRP is a fundamental component of the planned drilling program that certifies Shell’s 

capability to respond to the maximum extent practicable to a WCD (30 CFR 254.2) 

(see EP Section 9). The OSRP demonstrates Shell’s capabilities to rapidly and effectively manage 

oil spills that may result from drilling operations. Despite the extremely low likelihood of a large 

oil spill occurring during the project, Shell has designed its response program based upon a 

regional capability of responding to a range of spill volumes that increase from small operational 

spills to a WCD from a well blowout. Shell’s program is intended to meet the response planning 

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

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

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

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

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

to implement effective and sustained spill containment and recovery operations. 

EIA Organization 

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

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

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

Section C (Impact Analysis). 

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A. Impact-Producing Factors 

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

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

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

effect, an analysis is provided in Section C. Potential IPFs for the proposed activity are listed 

below and briefly discussed in the following subsections: 

 Drilling rig presence (including noise and lights); 

 Physical disturbance to the seafloor; 

 Air pollutant emissions; 

 Effluent discharges; 

 Water intake; 

 Onshore waste disposal; 

 Marine debris; 

 Support vessel and helicopter traffic; and 

 Accidents. 

A.1 Drilling Rig Presence (including noise and lights) 

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

an estimated 144 days per well. Offshore support vessels will be used during the drilling 

program, and there will likely be at least one vessel in the field at all times. The physical 

presence of a DP drillship or DP semisubmersible rig in the ocean can attract pelagic fishes and 

other marine life, as discussed in Section C.5.1. 

DP drillships and DP semisubmersible rigs are self-propelled and maintain position over a well 

using computer-controlled thrusters. Drilling operations produce noise that includes strong 

tonal components at low frequencies, including infrasonic frequencies in at least some cases 

(MMS, 2000). DP drillships can be expected to produce noise from both drilling and 

maintenance operations. 

Noise produced from drilling operations and vessel positioning may negatively affect 

threatened, endangered, and protected species, as discussed in Section C.3, and coastal and 

marine birds, as discussed in Section C.4. Drilling rigs and drillships also maintain exterior 

lighting for navigational and aviation safety in accordance with federal regulations. Artificial 

lighting may attract and directly or indirectly impact natural resources, as discussed in 

Section C.4. 

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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)

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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 and portions of Pensacola and Destin Dome area blocks in the 

Central Planning Area where seafloor habitats are protected by the Live Bottom (Low-Relief) Stipulation 

attached to an OCS lease. 

 The Live Bottom (Low-Relief) Stipulation is not applicable to the lease area. 

(4) Activities on blocks designated by the BOEM as being in water depths 300 m or greater. 

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

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

(610 m) of mud or cuttings discharge locations. 

(5) Exploration or production activities where H2S concentrations greater than 500 ppm might be encountered. 

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

(6) All activities that could result in an accidental spill of produced liquid hydrocarbons or diesel fuel that you 

determine would impact these environmental resources. If the proposed action is located a sufficient distance 

from a resource that no impact would occur, the EIA can note that in a sentence or two. 

 Accidental hydrocarbon spills could affect the resources marked (X) in the matrix, and impacts are 

analyzed in Section C. 

(7) All activities that involve seafloor disturbances, including anchor emplacements, in any OCS block designated 

by the BOEM as having high-probability for the occurrence of shipwrecks or prehistoric sites, including such 

blocks that will be affected that are adjacent to the lease block in which your planned activity will occur. If the 

proposed activities are located a sufficient distance from a shipwreck or prehistoric site that no impact would 

occur, the EIA can note that in a sentence or two. 

 No impacts on archaeological resources are expected. Although the lease area is on the list of 

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

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

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

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

occur. 

(8) All activities that you determine might have an adverse effect on endangered or threatened marine mammals 

or sea turtles or their critical habitats. 

 IPFs that may affect marine mammals, 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 

The wells will be drilled with a DP drillship or DP semisubmersible rig, which 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 and where mud and drill cuttings will be deposited. 

A.3 Air Pollutant Emissions 

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

emissions will result from operations of the drilling rig, as well as service vessels and helicopters. 

These emissions occur from internal combustion engines, most of which are driven by diesel 

fuel. The combustion of fuels occurs on diesel-powered generators, pumps, or motors and from 

lighter fuel motors. Primary air pollutants typically associated with OCS activities are suspended 

particulate matter (PM), sulfur oxides (SOx), nitrogen oxides (NOx), volatile organic compounds 

(VOCs), and carbon monoxide (CO). 

The Air Quality Emissions Report (see EP Section 8) prepared in accordance with BOEM 

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

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

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

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

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

required. 

A.4 Effluent Discharges 

Effluent discharges from the drilling rig are summarized in EP Section 7. Discharges from the 

drilling rig will be in compliance with and monitored as required by the National Pollutant 

Discharge Elimination System (NPDES) general permit for oil and gas activities in the western 

Gulf of Mexico (GMG 290000). 

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

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

slurry will also be released at the seafloor during casing installation for the riserless portion of 

the drilling operations. 

A synthetic-based mud (SBM) system will be used for drilling activities after the marine riser is 

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

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

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

with the NPDES permit limits for SBM fluid retained on cuttings. The estimated volume of 

SBM cuttings to be discharged is provided in EP Section 7. 

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

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

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

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

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

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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 

(EP Table 7a).

Section 316(b) of the Clean Water Act requires NPDES permits to ensure that the location, 

design, construction, and capacity of cooling water intake structures reflect the best technology 

available to minimize adverse environmental impact from impingement and entrainment of 

aquatic organisms. The NPDES General Permit No. GMG 290000 specifies requirements for new 

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

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

which at least 25% is used for cooling purposes. 

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

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

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

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

A.6 Onshore Waste Disposal 

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

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

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

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

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

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

Lamp Environmental of Hammond, Louisiana. At the respective onshore facilities, wastes will be 

recycled or disposed of according to applicable regulations. 

A.7 Marine Debris 

Trash and debris released into the marine environment can harm marine animals through 

entanglement and ingestion. Shell will adhere to the International Convention for the 

Prevention of Pollution from Ships (MARPOL 73/78) Annex V requirements, USEPA and 

USCG regulations, and BSEE regulations and NTLs regarding solid wastes. BSEE regulations at 

30 CFR 250.300(a) 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 shore-based facilities at Port Fourchon and Boothville, Louisiana, for 

onshore support for water and air transportation, respectively. No terminal expansion or 

construction is planned at either location. 

The supply base at Port Fourchon is operated by Shell and located on Bayou Lafourche, 

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

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

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

personnel and small supplies will normally take the most direct route of travel between the 

helicopter base and the lease area when air traffic and weather conditions permit. Helicopters 

typically maintain a minimum altitude of 700 ft (213 m) while in transit offshore; 1,000 ft 

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

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

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

of marine mammals (BOEM, 2012a). 

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

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

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

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

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

whereas broadband sounds may extend to 100 kHz. The primary sources of vessel noise are 

propeller cavitation, propeller singing, and propulsion; other sources include auxiliary engine 

noise, flow noise from water dragging along the hull, and bubbles breaking in the vessel’s wake 

while moving through the water (Richardson et al., 1995). Propeller cavitation is usually the 

dominant underwater noise source. The intensity of noise from service vessels is roughly 

related to ship size and speed. Broadband source levels for smaller boats (a category that would 

include supply and other service vessels) are in the range of 150 to 170 dB re 1 μPa at 1 m 

(Richardson et al., 1995). 

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

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

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

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

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

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

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

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

is much shorter in water than air; for example, a helicopter passing at an altitude of 152 m 

(500 ft) that is audible in air for 4 minutes may be detectable under water for only 38 seconds at 

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

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A.9 Accidents 

A.9.1 Types of Accidents Evaluated 

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

 a small fuel spill, which is the most likely type of spill during OCS exploration activities; and 

 an oil spill resulting from an uncontrolled blowout. A blowout resulting in a large oil spill is 

an extremely rare event, and the probability of such an event will be minimized by Shell’s 

well control and blowout prevention measures detailed in EP Section 2j. 

The following subsections summarize assumptions about the sizes and fates of these spills as 

well as Shell’s spill response plans. Impacts are analyzed in Section C. 

Previous lease sale EISs (MMS, 2007b; BOEM, 2012b,d) analyzed other types of accidents, 

including chemical spills, vessel collisions, and loss of well control. These accidents are 

discussed briefly in Section A.9.4. 

A.9.2 Small Fuel Spill 

Spill Size. According to the analysis in BOEM (2012b), the most likely type of small spill 

(<1,000 barrels [bbl]) as a result of OCS activities is a minor diesel fuel spill. Historically, most 

diesel spills have been <1 bbl, and this size is predicted to be the most common in ongoing and 

future OCS activities in the Western and Central Gulf of Mexico Planning Areas (BOEM, 2012b). 

The median size for spills <1 bbl is <0.024 bbl, and the median size for spills of 1 to 10 bbl is 3 bbl 

(BOEM, 2012b). For this analysis, a small diesel fuel spill of 3 bbl is assumed. Operational 

experience suggests that the most likely cause of such a spill would be a hose rupture resulting 

in the loss of the contents of a fuel transfer hose, which is less than 3 bbl. 

Spill Fate. The fate of a small fuel spill in the lease area would depend on meteorological and 

oceanographic conditions at the time, as well as the effectiveness of spill response activities. 

However, given the open ocean location of the lease area and the short duration of a small spill, 

the opportunity for impacts to occur would be very brief. 

The water-soluble fractions of diesel are dominated by two- and three-ringed polycyclic 

aromatic hydrocarbons (PAHs), which are moderately volatile (NRC, 2003b). The constituents of 

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

microbial oxidation. Diesel density is such that it will not sink to the seafloor. Diesel dispersed 

in the water column can adhere to suspended sediments, but this generally occurs only in 

coastal areas with high-suspended solids loads (NRC, 2003b) and would not be expected to 

occur to any appreciable degree in offshore waters of the Gulf of Mexico. Diesel oil is readily 

and completely degraded by naturally occurring microbes (NOAA, 2006). 

The fate of a small diesel fuel spill was estimated using NOAA’s Automated Data Inquiry for Oil 

Spills 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 more than 90% of a small diesel 

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

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

conditions. 

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The ADIOS2 results, coupled with spill trajectory information discussed in the next section for a 

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

lease area is 55 miles (89 km) from the nearest shoreline (Louisiana). Modeling results indicate 

that a surface spill in the lease area would have an 8% probability of contacting the nearest 

Louisiana shorelines within 30 days after a spill. Slicks from spills are expected to persist for 

relatively short periods of time ranging from minutes (<1 bbl) to hours (<10 bbl) to a few days 

(10 to 1,000 bbl) and rapidly spread out, evaporate and disperse into the water column 

(BOEM, 2012b). Because of the distance of these potential spills on the OCS and their lack of 

persistence, it is unlikely that a spill would make landfall prior to dissipation (BOEM, 2012b). 

Spill Response. In the unlikely event of a fuel spill, response equipment and trained personnel 

would be available to ensure that spill effects are localized and would result only in short-term, 

localized environmental consequences. EP Section 9b provides a detailed discussion of Shell’s 

response to a spill. 

A.9.3 Large Oil Spill 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures detailed in 

EP Section 2j. Blowouts are rare events and most do not result in oil spills (BOEM, 2012a). 

Spill Size. Shell has calculated a WCD for this EP using the requirements prescribed by 

NTL 2010-N06. The WCD is a 30-day average of 391,000 barrels of oil per day (BOPD). The 

detailed analysis of this calculation can be found in EP Section 2j. The WCD scenario for this EP 

has a low probability of occurrence. Some of the factors that are likely to reduce rates and 

volumes, which are not included in the WCD calculation, include, but are not limited to, 

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

containment. 

Shell has a robust system in place to prevent blowouts. Included in EP Sections 2j and 9b is

Shell’s response to NTL 2010-N06, which includes descriptions of measures to prevent a 

blowout, reduce the likelihood of a blowout, and conduct effective and early intervention in the 

event of a blowout. Shell will also comply with NTL 2010-N10 and the Final Drilling Safety Rule, 

which specify additional safety measures for OCS activities. 

Spill Trajectory. The fate of a large oil spill in the lease area would depend on meteorological 

and oceanographic conditions at the time. The Oil Spill Risk Analysis (OSRA) model is a 

computer simulation of oil spill transport that uses realistic data for winds and currents to 

predict spill fate. The OSRA report by Ji et al. (2004) provides conditional contact probabilities 

for shoreline segments. 

The results for Launch Area 58 (the launch area nearest to the lease area) are presented in 

Table 3. The model predicts no shoreline contact within 3 days. After 10 days, three parishes in 

Louisiana may be contacted, and after 30 days, 11 counties and parishes from Texas to Florida 

may be contacted. Plaquemines Parish, Louisiana, has the greatest probability of shoreline 

contact, with an 8% chance within 30 days. Other parishes and counties ranging from Texas to 

Florida have a 3% or less probability of shoreline contact within 30 days. 

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Table 3. Conditional probabilities of a spill in the lease area contacting shoreline segments 

(From: Ji et al., 2004). Values are conditional probabilities that a hypothetical spill in 

the lease area (represented by OSRA Launch Area 58) could contact shoreline 

segments within 3, 10, or 30 days. 

Shoreline 

Segment County or Parish, State Conditional Probability of 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 in Ji et al. (2004), the OSRA model does not take into account the chemical composition or 

biological weathering of oil spills, the spreading and splitting of oil spills, or spill response 

activities. The model does not assume a particular spill size but has generally been used by 

BOEM to evaluate contact probabilities for spills greater than 1,000 bbl. 

Weathering. Following an oil spill, several physical, chemical, and biological processes, 

collectively called weathering, interact to change the physical and chemical properties of the oil, 

and thereby influence its harmful effects on marine organisms and ecosystems. The most 

important weathering processes include spreading, evaporation, dissolution, dispersion into the 

water column, formation of water-in-oil emulsions, photochemical oxidation, microbial 

degradation, adsorption to suspended PM, and stranding on shore or sedimentation to the 

seafloor (NRC, 2003b).

Weathering decreases the concentration of oil and produces changes in its chemical 

composition, physical properties, and toxicity. The more toxic, light aromatic and aliphatic 

hydrocarbons are lost rapidly by evaporation and dissolution from the slick on the water 

surface. Evaporated hydrocarbons are degraded rapidly by sunlight. Biodegradation of oil on 

the water surface and in the water column by marine bacteria removes first the n-alkanes and 

then the light aromatics from the oil. Other petroleum components are biodegraded more 

slowly. Photooxidation attacks mainly the medium and high molecular weight PAHs in the oil on 

the water surface. 

Spill Response. Shell is a founding member of the Marine Well Containment Company (MWCC) 

and has access to an integrated subsea well control and containment system that can be rapidly 

deployed through the MWCC. The MWCC is a non-profit organization that assists with the 

subsea containment system during a response. The near-term containment response capability 

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will be specifically addressed in Shell’s NTL 2010-N10 submission at the time an Application for 

Permit to Drill is submitted and will include equipment and services available to Shell through 

MWCC’s development of near-term capability and other industry sources. Shell is a member of 

Clean Caribbean & Americas, Marine Spill Response Corporation, Clean Gulf Associates, and Oil 

Spill Response Limited, organizations that are committed to providing the resources necessary 

to respond to a spill as outlined in Shell’s OSRP.

Mechanical recovery capabilities are addressed in the OSRP. The mechanical recovery response 

equipment that could be mobilized to the spill location in normal and adverse weather 

conditions is included in the Offshore On-Water Recovery Activation List in the OSRP. 

Chemical dispersion capabilities are also readily available from resources identified in the OSRP. 

Available equipment for surface and subsea application of dispersants, response times, and 

support resources are identified in the OSRP. 

Open-water in situ burning may also be used as a response strategy, depending on the 

circumstances of the release. If appropriate conditions exist and approval from the Unified 

Command is received, one or multiple in situ burning task forces could be deployed offshore. 

See EP Section 9b for a detailed description of spill response measures. 

A.9.4 Other Accidents Not Analyzed in Detail 

The lease sale EIS (BOEM, 2012b) discusses four other types of accidents: chemical spills, 

pipeline failures, vessel collisions, and loss of well control. Three of these types of accidents 

considered relevant to this EP are briefly discussed in this section. No hydrogen sulfide (H2S) is 

expected at this site, and no other site-specific issues have been identified for this EP. The 

analysis in the lease sale EIS for these topics is incorporated by reference. 

Chemical Spill. Chemicals are used in drilling and producing operations to achieve technical 

goals in the drilling process, improve the efficiency and safety of drilling, and protect associated 

equipment. Chemicals used during drilling include surfactants, bentonite clays, olefins, 

inorganic salts, glycols, polymers, barite, and calcium carbonate. Supplies are renewed on a 

regular basis by transfer in containers from supply boats (Boehm et al., 2001). In addition to 

chemicals used in drilling fluids, the following chemicals are likely to be used on the rig: 

ethylene glycol (blowout prevention control fluid, used in closed cooling loops for crane and 

main engines and brake coolers), cement (used to cement casing in place), solvents (used in 

painting operations), hydraulic fluids (used in cranes and other hydraulic rig equipment), 

lubricating oil and grease (used in reciprocating and electrical equipment), and sodium 

hypochlorite (dilute, used as laundry bleach and disinfectant). 

A study of environmental risks of chemical products used in OCS activities determined that only 

two chemicals could potentially affect the marine environment in the concentrations typically 

used: zinc bromide and ammonium chloride (Boehm et al., 2001). The project addressed by this 

EP does not anticipate the use of either zinc bromide or ammonium chloride. Most other 

chemicals are either nontoxic or used in small quantities (BOEM, 2012b). No significant impacts 

are expected from chemical spills. 

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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, discussed in 

Section A.9.3, are considered to be a more serious subset of loss of well control incidents with 

greater risk of oil spill or human injury (MMS, 2007b). Not all loss of well control events result in 

blowouts (BOEM, 2012b). In addition to the potential release of gas, condensate, oil, sand, or 

water, the loss of well control can also resuspend and disperse bottom sediments 

(BOEM, 2012b). BOEM (2012b) noted that most OCS blowouts have resulted in the release of 

gas. 

Shell has a robust system in place to prevent loss of well control. Included in this EP is Shell’s 

response to NTL 2010-N06, which includes descriptions of measures to prevent a blowout, 

reduce the likelihood of a blowout, and conduct effective and early intervention in the event of 

a blowout. Shell will also comply with NTL 2010-N10 and the Final Drilling Safety Rule, which 

specify additional safety measures for OCS activities. See EP Sections 2j and 9b for further 

information. 

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

B. Affected Environment 

The lease area is in the central Gulf of Mexico, 55 miles (89 km) from the nearest shoreline, 

109 miles (175 km) from the onshore support base at Port Fourchon, Louisiana, and 80 miles 

(130 km) from the helicopter base at Boothville, Louisiana. 

Water depths at the proposed wellsites range from approximately 3,615 to 3,645 ft

(1,102 to 1,111 m). The proposed wellsites range from 300 to 687 ft (91 to 209 m) from the 

nearest minor seafloor faults. Wellsites range from 600 to 1,050 ft (183 to 320 m) from 

Shell’s MC 756 to 809 Ursa TLP flowline and umbilicals (C&C Technologies, Inc. [C&C, 2009a]; 

Fugro-McClelland Marine Geosciences, Inc [Fugro, 1991, 1992]). 

The geologic, stratigraphic, and archaeological assessment detected marine avoidance targets 

within 2,000 ft (610 m) of the proposed wellsites. Additional marine avoidance targets are 

present in the 2,000 to 3,000 ft (610 to 914 m) buffer zone around the wellsites (C&C, 2009a; 

Fugro, 1991, 1992). Each of these targets will be avoided by 100 ft (30 m) or more. Each target 

was assigned an Avoidance Zone Number, and targets’ exact coordinates were plotted to allow 

the drilling subcontractor to avoid them. 

The archaeological assessment confirmed the existence of modern debris primarily associated 

with prior industrial waste dumping or field development activities. A discontinued industrial 

waste dump area that was active in the 1970s is in the vicinity of the lease area (C&C, 2009b). 

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This dump site received containerized wastes until the site was closed. Waste barrels were 

identified within 2,000 ft (610 m) of Wellsites LL and MM, and within 3,000 ft (914 m) of 

Wellsites JJ, KK, LL, and MM (C&C, 2009a; Fugro, 1991, 1992). 

Shell’s procedure “Waste Barrel Avoidance and Release Response in the Mississippi Canyon 

Area,” which has been previously approved by MMS and BOEM[1], applies to operations that 

could cause a disturbance of a seafloor barrel. Shell’s overarching policy is to avoid barrel 

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

barrel, the plan specifies actions to be taken for the topside safety of personnel handling the 

equipment. The plan also outlines barrel impact reporting procedures. In this case, the 

geophysical survey subcontractors (C&C [C&C, 2009a] and Fugro [Fugro, 1991, 1992]) located 

each barrel and established specific 50 ft (15 m) avoidance distances around each. 

A detailed description of the regional affected environment is provided in MMS (2007b) and 

BOEM (2012b), including meteorology, oceanography, geology, air and water quality, benthic 

communities, threatened and endangered species, biologically sensitive resources, 

archaeological resources, socioeconomic conditions, and other marine uses. These regional 

descriptions are based on extensive literature reviews and are incorporated by reference. 

General background information is presented in the following sections, and brief descriptions of 

each potentially affected resource are presented in Section C, including site-specific and/or new 

information if available. 

The local environment in the lease area is not known to be unique with respect to 

physical/chemical, biological, or socioeconomic conditions. Baseline environmental conditions 

in the lease area are expected to be consistent with the regional description of continental slope 

locations evaluated in MMS (2007b) and BOEM (2012b). 

C. 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, 2007b; BOEM, 2012b). Site-specific issues are addressed in this 

section as appropriate. 

C.1 Physical/Chemical Environment 

C.1.1 Air Quality 

Due to the distance from shore-based pollution sources, offshore air quality is expected to be 

good. The attainment status of federal OCS waters is unclassified because there is no provision 

in the Clean Air Act for classification of areas outside state waters (MMS, 2007b). 

 

[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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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, Alabama, and Florida coastal 

counties and parishes are in attainment of the National Ambient Air Quality Standards (NAAQS) 

for all criteria pollutants (USEPA, 2012). One coastal metropolitan area in Texas 

(Houston-Galveston-Brazoria) is a nonattainment area for 8-hour ozone. One coastal 

metropolitan area in Florida (Tampa) is a nonattainment area for lead based on the 

2008 Standard. 

Winds in the region are driven by the clockwise circulation around the Bermuda High 

(BOEM, 2012b). The Gulf of Mexico is located to the southwest of this center of circulation, 

resulting in a prevailing southeasterly to southerly flow, which is conducive to transporting 

emissions toward shore. However, circulation is also affected by tropical cyclones (hurricanes) 

during summer and fall and by extratropical cyclones (cold fronts) during winter. 

IPFs that could potentially affect air quality are air pollutant emissions and two types of 

accidents: a small fuel spill and a large oil spill. 

Impacts of Air Pollutant Emissions 

Air pollutant emissions are the only routine IPF likely to affect air quality. Offshore air pollutant 

emissions will result from the operation of the drilling rig as well as helicopters and service 

vessels as described in Section A.3. These emissions occur mainly from combustion or burning 

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,d), emissions of air pollutants from routine activities in the Gulf of Mexico Central 

Planning Area are projected to have minimal impacts on onshore air quality because of the 

prevailing atmospheric conditions, emission heights, emission rates, and the distance of these 

emissions from the coastline. 

The Air Quality Emissions Report (see EP Section 8) prepared in accordance with BOEM 

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

proposed activities meet the BOEM exemption criteria. This EP is therefore exempt from 

further air quality review pursuant to 30 CFR 550.303(d). 

The Breton Wilderness Area, which is part of the Breton National Wildlife Refuge (NWR), is 

designated under the Clean Air Act as a Prevention of Significant Deterioration Class I air quality 

area. The BOEM coordinates with the National Park Service and the USFWS if emissions from 

proposed projects may affect the Breton Class I area. The lease area is approximately 90 miles 

(145 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. 

Carbon dioxide (CO2) and methane (CH4) emissions from the project would constitute a 

negligible contribution to greenhouse gas emissions from all OCS activities. According to 

programmatic and OCS lease sale EISs (BOEM, 2012a,b), estimated CO2 emissions from OCS oil 

and gas sources are 0.4% of the U.S. total. All OCS activities contribute approximately 0.005% to 

total global CO2 emissions. Greenhouse gas emissions may contribute to climate change, with 

important effects on temperature, rainfall, frequency of severe weather, ocean acidification, 

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and sea level rise (Intergovernmental Panel on Climate Change, 2007). Greenhouse gas 

emissions from this proposed project represent a negligible contribution to the total greenhouse 

gas emissions from reasonably foreseeable activities in the Gulf of Mexico area and would not 

significantly alter any of the climate change impacts evaluated in the Programmatic EIS 

(BOEM, 2012a).

Impacts of a Small Fuel Spill 

Potential impacts of a small spill on air quality are expected to be consistent with those analyzed 

and discussed in MMS (2007b) and BOEM (2012b,d). The probability of a small spill would be 

minimized by Shell’s preventative measures during routine operations, including fuel transfer. 

In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Given the open ocean 

location of the lease area, the extent and duration of air quality impacts from a small spill would 

not be significant. 

A small fuel spill would likely affect air quality near the spill site by introducing VOCs through 

evaporation. The ADIOS2 model (see Section A.9.2) indicates that more than 90% of a small 

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

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

conditions. 

A small fuel spill would not affect coastal air quality because the spill would not be expected to 

make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill 

Potential impacts of a large oil spill on air quality are expected to be consistent with those 

analyzed and discussed in MMS (2007b) and BOEM (2012b,d).

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 (55 miles [89 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, Cameron Parish, Terrebonne Parish, and 

Lafourche Parish, Louisiana, are the coastal areas most likely to be affected. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on air quality are expected. 

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C.1.2 Water Quality 

Deepwater areas in the Gulf of Mexico are relatively homogeneous with respect to temperature, 

salinity, and oxygen (MMS, 2007b). IPFs that could potentially affect water quality are effluent 

discharges and two types of accidents: a small fuel spill and a large oil spill. 

Impacts of Effluent Discharges 

Discharges of treated SBM cuttings will produce temporary, localized increases in suspended 

solids in the water column around the drilling rig. In general, turbid water can be expected to 

extend between a few hundred meters and several kilometers down current from the discharge 

point (NRC, 1983; Neff, 1987). NPDES permit limits and requirements will be met. After 

discharge, SBM retained on cuttings would be expected to adhere tightly to the cuttings 

particles and, consequently, would not produce much turbidity as the cuttings sink through the 

water column (Neff et al., 2000). Recent EISs have concluded that the discharge of treated 

SBM cuttings will not cause persistent impacts on water quality in the lease area 

(BOEM 2012b,d).

Treated sanitary and domestic wastes may have a slight transient effect on water quality in the 

immediate vicinity of these discharges. NPDES permit limits and requirements will be met, and 

little or no impact on water quality is anticipated. 

Deck drainage includes effluents resulting from rain, deck washings, and runoff from curbs, 

gutters, and drains, including drip pans in work areas. Rainwater that falls on uncontaminated 

areas of the drilling rig will flow overboard without treatment. However, rainwater that falls on 

the drilling rig deck and other areas such as chemical storage areas and places where equipment 

is exposed will be collected and oil and water separated to meet NPDES permit requirements. 

Negligible impact on water quality is anticipated. 

Other discharges from the proposed drilling rig will be in accordance with the NPDES permit. 

Discharges include desalination unit brine and uncontaminated cooling water, fire water, and 

ballast water and are expected to be diluted rapidly and have little or no impact on water 

quality. 

Support vessels will discharge treated sanitary and domestic wastes. These will have a slight 

effect on water quality in the immediate vicinity of the discharges. Support vessel discharges 

are subject to USCG regulations and therefore are not expected to cause significant impacts on 

water quality. 

Impacts of a Small Fuel Spill 

Potential impacts of a small spill on water quality are expected to be consistent with those 

analyzed and discussed in MMS (2007b) and BOEM (2012b,d). The probability of a small spill 

would be minimized by Shell’s preventative measures during routine operations, including fuel 

transfer. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce 

the impacts. EP Section 9b provides detail on spill response measures. Given the open ocean 

location of the lease area, the extent and duration of water quality impacts from a small spill 

would not be significant. 

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A small fuel spill in offshore waters would increase the concentrations of petroleum 

hydrocarbons and their degradation products. The extent and persistence of impacts would 

depend on the meteorological and oceanographic conditions at the time and the effectiveness 

of spill response measures. However, it is estimated that more than 90% of a small diesel spill 

would be evaporated or dispersed within 24 hours (see Section A.9.2). The area of diesel fuel 

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

weather conditions. 

The water-soluble fractions of diesel are dominated by two- and three-ringed PAHs, which are 

moderately volatile (NRC, 2003b). The constituents of these oils are light to intermediate in 

molecular weight and can be readily degraded by aerobic microbial oxidation. Diesel’s density is 

such that it will not sink and pool on the seafloor. Diesel dispersed in the water column can 

adhere to suspended sediments, but this generally occurs only in coastal areas with high 

suspended solids loads (NRC, 2003b) and would not be expected to occur to any appreciable 

degree in offshore waters of the Gulf of Mexico. Diesel oil is readily and completely degraded 

by naturally occurring microbes (NOAA, 2006). 

A small fuel spill would not affect coastal water quality because the spill would not be expected 

to make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill 

Potential impacts of a large oil spill on water quality are expected to be consistent with those 

analyzed and discussed in MMS (2007b) and BOEM (2012b,d). A large spill would likely affect 

water quality by producing a slick on the water surface and increasing the concentrations of 

petroleum hydrocarbons and their degradation products. The extent and persistence of impacts 

would depend on the meteorological and oceanographic conditions at the time and the 

effectiveness of spill response measures. Most of the oil would be expected to form a slick at 

the surface, although observations following the Macondo spill indicate that plumes of 

submerged oil droplets can be produced when subsea dispersants are applied at the wellhead 

(Camilli et al., 2010; Hazen et al., 2010; Joint Analysis Group, 2010a,b,c). Recent analyses of the 

full set of samples associated with the Macondo spill have confirmed that the application of 

subsurface dispersants resulted in subsurface hydrocarbon plumes (Spier et al., 2013). A report 

by Kujawinski et al. (2011) indicates that chemical components of subsea dispersants used 

during the Macondo spill persisted for up to 2 months and were detectable up to 186 miles 

(300 km) from the wellsite at a water depth of 3,280 to 3,937 ft (1,000 to 1,200 m). While 

dispersants were detectable in 353 of the 4,114 total water samples, concentrations in the 

samples were significantly below the chronic screening level for dispersants (BOEM, 2012d). 

Once oil enters the ocean, a variety of physical, chemical, and biological processes act to 

disperse the oil slick. These processes include spreading, evaporation of the more volatile 

constituents, dissolution into the water column, emulsification of small droplets, agglomeration 

sinking, microbial modification, photochemical modification, and biological ingestion and 

excretion (NRC, 2003b). Marine water quality would be temporarily affected by the dissolved 

components and small oil droplets that do not rise to the surface or are mixed down by surface 

turbulence. Dispersion by currents and microbial degradation removes the oil from the water 

column or dilutes the constituents to background levels. 

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A large oil spill could result in a release of gaseous hydrocarbons that could affect water quality. 

During the Macondo spill, large volumes of CH4 were released, causing localized oxygen 

depletion as methanotrophic bacteria rapidly metabolized the hydrocarbons (Joye et al., 2011; 

Kessler et al., 2011). However, a broader study of the deepwater Gulf of Mexico found that 

although some stations showed slight depression of dissolved oxygen concentrations relative to 

climatological background values, the findings were not indicative of hypoxia (<2.0 mg/L) 

(Operational Science Advisory Team [OSAT], 2010). Stations revisited around the Macondo 

wellhead in October 2010 showed no measurable oxygen depressions (OSAT, 2010). 

Due to the lease area location (55 miles [89 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, 

Cameron Parish, Terrebonne Parish, and Lafourche Parish, Louisiana, are the coastal areas most 

likely to be affected. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on water quality are expected. 

C.2 Seafloor Habitats and Biota 

Water depths at the proposed well surface locations range from approximately 3,615 to 3,645 ft 

(1,102 to 1,111 m). See EP Section 6a for further information. 

According to the BOEM (2012b), existing information for the deepwater Gulf of Mexico indicates 

that the seafloor is composed primarily of soft sediments; hard bottom communities are rare. 

MC 809 is within deepwater Grid 13 where remotely operated vehicle 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 similar, predominantly clay (45.5% at MT4 and 52.9% at C7) and silt 

(45.5% at MT4 and 38.1% at C7) (Rowe and Kennicutt, 2009).

Table 4. Benthic community data from stations nearest to the lease area in similar water 

depths sampled during the Northern Gulf of Mexico Continental Slope Habitats and 

Benthic Ecology Study (From: Wei, 2006; Rowe and Kennicutt, 2009). 

Station

Location 

Relative to 

Lease Area

Water Depth

(m)

Abundance

Meiofauna

(individuals/m2)

Macroinfauna

(individuals/m2)

Megafauna

(individuals/ha)

MT4 26 mi SSW 1,403 246,058 3,262 1,548

C7 60 mi WSW 1,022 542,119 3,293 625

Meiofaunal and megafaunal abundance from Rowe and Kennicutt (2009); macroinfaunal abundance from Wei (2006). 

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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 200,000 to 

350,000 individuals/m2 (Rowe and Kennicutt, 2009). Nematodes, nauplii, and harpacticoid 

copepods were the three dominant groups in the meiofauna, accounting for about 90% of total 

abundance. 

The benthic macroinfauna is characterized by small mean individual sizes and low densities, 

both of which are a reflection of the meager primary production in Gulf of Mexico surface 

waters (Wei, 2006). Densities decrease exponentially with water depth. Based on an equation 

presented by Wei (2006), macroinfaunal densities in the water depth of the wellsites are 

expected to be about 3,002 individuals/m2, lower than the values in Table 4. 

Polychaetes are typically the most abundant macroinfaunal group on the northern Gulf of 

Mexico continental slope, followed by amphipods, tanaids, bivalves, and isopods. Wei (2006) 

recognized four depth-dependent faunal zones (1 through 4), two of which are divided 

horizontally. The lease area is in Zone 2E, which consists of stations ranging in depth from 

2,831 to 5,315 ft (625 to 1,828 m), covering mid Texas-Louisiana Slope, the west flank of the 

Mississippi Fan, the mid Mississippi Canyon, the head of De Soto Canyon, and the mid West 

Florida Terrace. The five most abundant species in Zone 2E were the polychaetes 

Aricidea suecica, Exogone sp. A., Paralacydonia paradoxa, and Tharyx annulosus.

Megafaunal density from nearby station MT4 was 1,548 individuals/ha (Table 4). Densities of 

195 to 2,941 individuals/ha were reported from other stations in a similar depth range. 

Common megafauna included motile groups such as decapods, ophiuroids, holothurians, and 

demersal fishes, as well as sessile groups such as sponges and anemones. 

Bacteria are the foundation of deep-sea chemosynthetic communities (Ross et al., 2012) and are 

an important component in terms of biomass and cycling of organic carbon (Cruz-Kaegi, 1998). 

Bacterial biomass at the depth range of the lease area typically is about 1 to 2 grams of carbon 

per square meter (g C m−2) in the top 6 in. (15 cm) of sediments (Rowe and Kennicutt, 2009). 

IPFs that could potentially affect benthic communities are physical disturbance, effluent 

discharges (drilling mud and cuttings), and a large oil spill resulting from a well blowout at the 

seafloor. A small fuel spill would not affect benthic communities because the diesel fuel would 

float and dissipate on the sea surface. 

Impacts of Physical Disturbance to the Seafloor 

In water depths such as those that are encountered in the lease area, DP drillships or 

DP semisubmersible rigs disturb the seafloor only around the wellbore (surface hole location) 

where the bottom template and blowout preventer are located. Depending upon the specific 

well configuration, this area is generally about 0.62 ac (0.25 ha) (BOEM, 2012b). 

The areal extent of these impacts from the drilling rig will be small compared to the lease area 

itself. Soft bottom communities are ubiquitous along the northern Gulf of Mexico continental 

slope (Gallaway et al., 2003; Rowe and Kennicutt, 2009). Physical disturbance to the seafloor 

during this project will have no significant impact on soft bottom benthic communities on a 

regional basis. 

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Impacts of Effluent Discharges 

Drilling mud and cuttings are the only effluents likely to affect benthic communities. During 

initial well interval(s) before the marine riser is set, cuttings and seawater-based “spud mud” 

will be released at the seafloor. Excess cement slurry will also be released at the seafloor during 

casing installation for the riserless portion of the drilling operations. Cement slurry components 

typically include cement mix and some of the same chemicals used in water-based drilling mud 

(Boehm et al., 2001). The main impacts will be burial and smothering of benthic organisms 

within several meters to tens of meters around the wellbore. Soft bottom sediments disturbed 

by cuttings, drilling mud, and cement slurry will eventually be recolonized through larval 

settlement and migration from adjacent areas. Because some deep-sea biota grow and 

reproduce slowly, recovery may require several years. 

Discharges of treated SBM cuttings from the rig may affect benthic communities, primarily 

within several hundred meters of the wellsites. The fate and effects of SBM cuttings have been 

reviewed by Neff et al. (2000), and monitoring studies have been conducted in the Gulf of 

Mexico by Continental Shelf Associates, Inc. (2004, 2006). In general, cuttings with adhering 

SBM tend to clump together and form thick cuttings piles close to the drillsite. Areas of 

SBM cuttings deposition may develop elevated organic carbon concentrations and anoxic 

conditions (Continental Shelf Associates, Inc., 2006). Where SBM cuttings accumulate and 

concentrations exceed approximately 1,000 mg/kg, benthic infaunal communities may be 

adversely affected due to both the toxicity of the base fluid and organic enrichment 

(with resulting anoxia) (Neff et al., 2000). Infaunal numbers may increase and diversity may 

decrease as opportunistic species that tolerate low oxygen and high H2S predominate 

(Continental Shelf Associates, Inc., 2006). As the base synthetic fluid is decomposed by 

microbes, the area will gradually return to pre-drilling conditions. Disturbed sediments will be 

recolonized through larval settlement and migration from adjacent areas. 

The areal extent of impacts from drilling discharges will be small; the typical effect radius is 

1,640 ft (500 m) around each wellsite. For the six surface locations in this exploration-drilling 

program, the total impact area would be 1,165 ac (471 ha). In light of the proximity of the 

proposed wells to each other, the overall impact area could be reduced. Soft bottom 

communities are ubiquitous along the northern Gulf of Mexico continental slope (Gallaway, 

1988; Gallaway et al., 2003; Rowe and Kennicutt, 2009). Impacts from drilling discharges during 

this project will have no significant impact on soft bottom benthic communities on a 

regional basis. 

Impacts of a Large Oil Spill 

Potential impacts of a large oil spill on the benthic community are expected to be consistent 

with those analyzed and discussed in MMS (2007b) and BOEM (2012b,d). Likely impacts from a 

subsea blowout include smothering and exposure to toxic hydrocarbons from oiled sediment 

settling to the seafloor. The most likely effects of a subsea blowout on benthic communities 

would be within a few hundred meters of the wellsites. The MMS (2007b) estimates that a 

severe subsurface blowout could resuspend and disperse sediments within a 984-ft (300-m) 

radius. While coarse sediments (sands) would probably settle at a rapid rate within 1,312 ft 

(400 m) from the blowout site, fine sediments (silts and clays) could be resuspended for more 

than 30 days and dispersed over a much wider area. Previous studies characterized surface 

sediments in the vicinity of the site as about 53% clay and 38% silt (Rowe and Kennicutt, 2009). 

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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; Spier et al., 

2013). Chemical components of subsea dispersants used during the Macondo spill persisted for 

up to 2 months and were detected up to 186 miles (300 km) from the wellsite at a water depth 

of 3,280 to 3,937 ft (1,000 to 1,200 m) (Kujawinski et al., 2011). However, estimated dispersant 

concentrations in the subsea plume were below levels known to be toxic to marine life. While 

the behavior and impacts of subsurface plumes are not well known, a subsurface plume could 

contact the seafloor and affect benthic communities beyond the 984-ft (300-m) radius 

estimated in MMS (2007a, 2008), depending on its extent, trajectory, and persistence 

(Spier et al., 2013). This contact could result in smothering and/or toxicity to benthic organisms. 

The affected area would be recolonized by benthic organisms over a period of months to years 

(NRC, 2003b).

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on soft bottom communities are expected. 

C.2.2 High-Density Deepwater Benthic Communities 

As defined in NTL 2009-G40, high-density deepwater benthic communities are features or areas 

that could support high-density chemosynthetic communities, high-density deepwater corals, or 

other associated high-density hard bottom communities. Chemosynthetic communities were 

discovered in the central Gulf of Mexico in 1984 and have been studied extensively 

(MacDonald, 2002). Deepwater coral communities are also known from numerous locations in 

the Gulf of Mexico (Brooke and Schroeder, 2007; CSA International, Inc., 2007). These 

communities occur almost exclusively on authigenic carbonates created by chemosynthetic 

communities, and on shipwrecks. The nearest known high-density deepwater benthic 

community site is located approximately 3 miles (5 km) south-southwest of the lease area in 

MC 853 (Brooks et al., 2009). 

The site clearance surveys by Fugro (1991, 1992) and C&C (2009a) did not identify any features 

that could support high-density deepwater benthic communities within 2,000 ft (610 m) of the 

proposed drilling mud/cuttings discharge locations. 

IPFs that could potentially affect high-density deepwater benthic communities are effluent 

discharges (drilling mud and cuttings), and a large oil spill from a well blowout at the seafloor. 

A small fuel spill would not affect benthic communities because the diesel fuel would float and 

dissipate on the sea surface. 

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Impacts of Effluent Discharges 

The site clearance assessments included in this EP, based on the reports by Fugro (1991, 1992) 

and C&C (2009a) did not identify features that could support high-density deepwater benthic 

communities within 2,000 ft (610 m) of the proposed drilling mud/cuttings discharge locations.

Monitoring programs on the Gulf of Mexico continental slope have shown that benthic impacts 

from drilling discharges typically are concentrated within about 1,640 ft (500 m) of the wellsites, 

although detectable deposits may extend beyond this distance (Continental Shelf Associates, 

Inc., 2004, 2006; Neff et al., 2005). If high-density deepwater communities are associated with 

the more distant expulsion features and mud volcanoes identified in the hazards survey, 

significant impacts on these communities will be avoided because of the distance from the 

discharge location. 

Impacts of a Large Oil Spill 

The BOEM (2012a) concluded that oil spills would be unlikely to affect benthic communities 

beyond the immediate vicinity of the wellhead (i.e., due to physical impacts of a blowout) 

because the oil would rise quickly to the sea surface directly over the spill location. However, 

during the Macondo spill, subsurface plumes were reported at a water depth of about 3,600 ft 

(1,100 m), extending at least 22 miles (35 km) from the wellsite and persisting for more than a 

month (Camilli et al., 2010). The subsurface plumes apparently resulted from the use of 

dispersants at the wellhead (Joint Analysis Group, 2010c). Chemical components of subsea 

dispersants used during the Macondo spill persisted for up to 2 months and were detectable up 

to 186 miles (300 km) from the wellsite at a water depth of 3,280 to 3,937 ft (1,000 to 1,200 m) 

(Kujawinski et al., 2011). However, estimated dispersant concentrations in the subsea plume 

were below levels known to be toxic to marine life. While the behavior and impacts of 

subsurface plumes are not well known, a subsurface plume could have the potential to contact 

high-density deepwater benthic communities beyond the 984-ft (300-m) radius estimated in 

BOEM (2012a), depending on its extent, trajectory, and persistence. Oil plumes that contact 

sensitive benthic communities before degrading could potentially impact the resource 

(BOEM, 2012b). Potential impacts on sensitive resources would be an integral part of the 

decision and approval process for the use of dispersants. The site clearance assessments by 

Fugro (1991, 1992) and C&C (2009a) did not identify high-density deepwater benthic 

communities within 2,000 ft (610 m) of the proposed drilling mud/cuttings discharge locations. 

Potential impacts of oil on high-density deepwater benthic communities are discussed in 

MMS (2007b) and BOEM (2012b). 

Although chemosynthetic communities live among hydrocarbon seeps, natural seepage occurs 

at a relatively constant low rate compared with the potential rates of oil release from a blowout. 

In addition, seep organisms require unrestricted access to oxygenated water at the same time as 

exposure to hydrocarbon energy sources (MacDonald, 2002). Oil droplets or oiled sediment 

particles could come into contact with chemosynthetic organisms or deepwater corals. 

As discussed in MMS (2007b), impacts could include loss of habitat, biodiversity, and live coral 

coverage; destruction of hard substrate; change in sediment characteristics; and reduction or 

loss of one or more commercial and recreational fishery habitats. Sublethal effects could be 

long lasting and affect the resilience of coral colonies to natural disturbances (e.g., elevated 

water temperature and diseases) (BOEM 2012d). 

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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 53 miles 

(85 km) east-northeast of the activities discussed in this EIA. There would not likely be 

cumulative impacts to those corals even in the unlikely event of a large spill associated with the 

activities discussed in this EIA.

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Potential 

impacts on sensitive resources would be an integral part of the decision and approval process 

for the use of dispersants. Therefore, no significant spill impacts on deepwater benthic 

communities are expected. 

C.2.3 Designated Topographic Features 

The block is not within or near a designated topographic feature or a no-activity zone as 

identified in NTL 2009-G39. The nearest designated topographic feature stipulation block is 

Sackett Bank in West Delta Block 147, located 41 miles (66 km) northwest of the lease area. 

There are no IPFs associated with either routine operations or accidents that could cause 

impacts to designated topographic features due to the distance from the lease area.

C.2.4 Pinnacle Trend Area Live Bottoms 

The lease area is not covered by the Live Bottom (Pinnacle Trend) Stipulation. As defined in 

NTL 2009-G39, the nearest pinnacle trend blocks are located about 85 miles (137 km) 

north-northeast of the lease area in Main Pass Block 290. 

There are no IPFs associated with either routine operations or accidents that could cause 

impacts to pinnacle trend area live bottoms due to the distance from the lease area. 

C.2.5 Eastern Gulf Live Bottoms 

The lease area is not covered by the Live Bottom (Low-Relief) Stipulation, which pertains to 

seagrass communities and low-relief hard-bottom reef within the Gulf of Mexico Eastern 

Planning Area blocks in water depths of 328 ft (100 m) or less and portions of Pensacola and 

Destin Dome Area Blocks in the Central Planning Area. The nearest blocks covered by the live 

bottom stipulation, as defined in NTL 2009-G39, are about 119 miles (191 km) northeast of the 

project area. 

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There are no IPFs associated with either routine operations or accidents that could cause 

impacts to eastern Gulf of Mexico live bottom areas due to the distance from the lease area. 

C.3 Threatened, Endangered, and Protected Species and Critical Habitat 

This section discusses species listed as endangered or threatened under the ESA. In addition, it 

includes all marine mammal species in the region, 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.

Table 5. Federally listed endangered and threatened species in the lease area and along the 

northern Gulf Coast. 

Species Scientific Name Status

Potential 

Presence Critical Habitat 

Designated in

Gulf of Mexico Lease 

Area Coastal

Marine Mammals

Sperm whale Physeter macrocephalus E X -- None

Florida manatee Trichechus manatus 

latirostris

E -- X

Florida 

(Peninsular)

Blue whale Balaenoptera musculus E X

a

-- None

Fin whale Balaenoptera physalus E X

a

-- None

Humpback whale Megaptera novaeangliae E X

a

-- None

North Atlantic right whale Eubalaena glacialis E X

a

-- None

Sei whale Balaenoptera borealis E X

a

-- None

Sea Turtles

Loggerhead turtle Caretta caretta T, EbX X None

Green turtle Chelonia mydas T, EcX X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempii E X X None

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)

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Table 5. (Continued.) 

Species Scientific Name Status

Potential 

Presence Critical Habitat 

Designated in

Gulf of Mexico Lease 

Area Coastal

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.

The sperm whale and five species of sea turtles are the only endangered or threatened species 

likely to occur at or near the lease area. No critical habitat has been designated for these 

species in the Gulf of Mexico. 

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right 

whale, and sei whale) have also been reported from the Gulf of Mexico but are considered rare 

or extralimital there (Würsig et al., 2000). No critical habitat has been designated for these 

species in the Gulf of Mexico. 

Coastal endangered or threatened species include the 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 in MMS (2007b) and 

BOEM (2012b) are no longer federally listed as endangered or threatened; these species are 

discussed in Section C.4.2, Shorebirds and Coastal Nesting Birds. 

There are no other endangered animals or plants in the Gulf of Mexico that are reasonably likely 

to be affected by either routine or accidental events. Other species occurring at certain 

locations in the Gulf of Mexico such as the smalltooth sawfish (Pristis pectinata), elkhorn coral 

(Acropora palmata), staghorn coral (Acropora cervicornis), and Florida salt marsh vole 

(Microtus pennsylvanicus dukecampbelli) are remote from the lease area and highly unlikely to 

be affected. 

C.3.1 Sperm Whale (Endangered) 

The only endangered marine mammal likely to be present at or near the project area is the 

sperm whale (Physeter macrocephalus). Resident populations of sperm whales occur within the 

Gulf of Mexico. A species description is presented in MMS (2007b). Gulf of Mexico sperm 

whales are classified as an endangered species and a “strategic stock” (defined as a stock that 

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may have unsustainable human-caused impacts) by NMFS (Waring et al., 2013). No critical 

habitat for the sperm whale has been designated in the Gulf of Mexico. 

The distribution of sperm whales in the Gulf of Mexico is correlated with mesoscale physical 

features such as eddies associated with the Loop Current (Jochens et al., 2008). Sperm whale 

populations in the north-central Gulf of Mexico are present there throughout the year 

(Davis et al., 2000). Results of a multi-year tracking study show female sperm whales typically 

concentrated along the upper continental slope between the 656- and 3,280-ft (200- and 

1,000-m) depth contours (Jochens et al., 2008). Male sperm whales were more variable in their 

movements and were documented in water depths greater than 9,843 ft (3,000 m). Generally, 

groups of sperm whales sighted in the Gulf of Mexico during the MMS-funded Sperm Whale 

Seismic Study consisted of mixed-sex groups comprising adult females and immatures, and 

groups of bachelor males. Typical group size for mixed groups was 10 individuals (Jochens et al., 

2008). A review of sighting reports from seismic mitigation surveys in the Gulf of Mexico 

conducted over a 6-year period found a mean group size for sperm whales of 2.5 individuals 

(Barkaszi et al., 2012). 

In these mitigation surveys, sperm whales were the most common cetacean encountered 

(Barkaszi et al., 2012). Results of the Sperm Whale Seismic Study showed that sperm whales 

transit through the vicinity of the lease area. Movements of satellite-tracked individuals suggest 

that this area of the Gulf continental slope is within the home range of the Gulf of Mexico 

population (within the 95% utilization distribution) (Jochens et al., 2008). 

Current threats to sperm whale populations worldwide are discussed in a final recovery plan for 

the sperm whale published by NOAA (NMFS, 2010a). Threats are defined as “any factor that 

could represent an impediment to recovery,” and include fisheries interactions, anthropogenic 

noise, vessel interactions, contaminants and pollutants, disease, injury from marine debris, 

research, predation and natural mortality, direct harvest, competition for resources, loss of prey 

base due to climate change and ecosystem change, and cable laying. In the Gulf of Mexico, the 

impacts from many of these threats are identified as either low or unknown (BOEMRE, 2011; 

BOEM, 2012c). 

IPFs that could potentially affect sperm whales include drilling rig presence, noise, and lights; 

support vessel and helicopter traffic noise; support vessel strikes; and two types of accidents –

a small fuel spill and a large oil spill. Effluent discharges are likely to have negligible impacts on 

sperm whales due to rapid dispersion, the small area of ocean affected, the intermittent nature 

of the discharges, and the mobility of these marine mammals. Compliance with 

NTL 2012-BSEE-G01 will minimize the potential for marine debris-related impacts on 

sperm whales. 

Impacts of Drilling Rig Presence, Noise, and Lights 

Noise generated from the drilling rig(s) and from routine drilling activities has the potential to 

disturb sperm whales. Some sounds produced by the drilling rig may be emitted at levels that 

could potentially disturb individual whales or mask the sounds animals would normally produce 

or hear. Noise associated with drilling is relatively weak in intensity, and an individual animal’s 

noise exposure would be transient. As discussed in Section A.1, the bandwidth of sounds 

generated by the drilling rig is approximately 10 to 500 Hz.

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Sperm whales appear to have good low-frequency hearing, with variable responses to 

anthropogenic noise (Jochens et al., 2008). Southall et al. (2007) list sperm whales in the same 

hearing group (i.e., mid-frequency cetaceans) as dolphins, toothed whales, beaked whales, and 

bottlenose whales (estimated hearing range from 150 Hz to 160 kHz). Generally, most of the 

acoustic energy from sperm whales is present at frequencies below 4 kHz, although diffuse 

energy up to and past 20 kHz has been reported, with source levels up to 236 dB re 1 μPa at 

1 m. Most observations of behavioral responses of marine mammals to anthropogenic sounds, 

in general, have been limited to short-term behavioral responses, which included the cessation 

of feeding, resting, or social interactions (NMFS, 2009a). 

Sounds produced during drilling operations are generally constant (rather than pulsed or 

intermittent) and at levels that may be louder than, and of a similar frequency to, the auditory 

signal received by sperm whales. Animals can determine the direction from which a sound 

arrives based on cues, such as difference in arrival times, sound levels, and phases at the two 

ears. Thus, an animal’s directional hearing capabilities have a bearing on its vulnerability to 

masking (NRC, 2003a). Behavioral changes for marine mammals such as the sperm whale to 

auditory masking sounds may include producing more calls, longer calls, or shifting the 

frequency of the calls (NMFS, 2009a; Holt et al., 2009). 

In addition, there are other OCS facilities and activities near the lease area, and the region as a 

whole has a large number of similar sound sources. Drilling-related noise associated with this 

project will contribute to increases in the ambient noise environment of the Gulf of Mexico, but 

it is not expected in amplitudes sufficient enough to cause either hearing or behavioral effects 

to sperm whales. 

The drilling rig used during the proposed activity will be located within a deepwater, open ocean 

environment and will remain stationary during drilling operations. Sounds generated by the rig 

and by drilling operations will be generally continuous with some variability in sound level. This 

analysis assumes that the continuous nature of sounds produced by the drilling rig will provide 

individual whales with cues relative to the direction and relative distance (sound intensity) of 

the sound source, and the fixed position of the drilling rig will provide multiple options for active 

avoidance of potential physical impacts. 

NMFS analyzed the potential for impacts of drilling-related noise on sperm whales in its 

Biological Opinion for the Five-Year Oil and Gas Leasing Program in the Central and Western 

Planning Areas of the Gulf of Mexico (NMFS, 2007). The analysis noted that drilling rigs show 

low sound source levels and concluded that drilling is not expected to produce amplitudes 

sufficient to cause hearing or behavioral effects in sperm whales; therefore, these effects are 

insignificant (NMFS, 2007). In other areas, such as the Beaufort Sea, NMFS (2009a) stated that 

marine mammals that show behavioral avoidance to noise related to drilling activities are 

especially unlikely to incur auditory impairment or other physical effects (Federal Register, 

Vol. 75, No. 88; Friday, May 7, 2010/Notices). 

Although offshore lighting and presence of drilling rigs and OCS vessels were considered 

potential factors affecting sperm whales, NMFS’s 2007 Biological Opinion and lease sale EISs 

(MMS, 2007b; BOEM, 2012b,d) did not identify these as IPFs for sperm whales. Therefore, no 

significant impacts are expected. 

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Impacts of Support Vessel and Helicopter Traffic 

Support vessel traffic has the potential to disturb sperm whales. There is also a risk of vessel 

strikes, which are identified as a threat in the recovery plan for this species (NMFS, 2010a). Data 

concerning the frequency of vessel strikes are presented in the lease sale EIS (MMS, 2007b). 

To reduce the potential for vessel strikes, the BOEM has issued NTL 2012-JOINT-G01, which 

recommends protected species identification training and that vessel operators and crews 

maintain a vigilant watch for marine mammals and slow down or stop their vessel to avoid 

striking protected species, and requires operators to report sightings of any injured or dead 

protected species. When whales are sighted, vessel operators and crews are required to 

attempt to maintain a distance of 300 ft (91 m) or greater whenever possible. Vessel operators 

are required to reduce vessel speed to 10 knots or less, when safety permits, when mother/calf 

pairs, pods, or large assemblages of cetaceans are observed near an underway vessel. 

Compliance with this NTL will minimize the likelihood of vessel strikes as well as reduce the 

chance for disturbing sperm whales. 

NMFS (2007) analyzed the potential for vessel strikes and harassment of sperm whales in its 

Biological Opinion for the Five-Year Oil and Gas Leasing Program in the Central and Western 

Planning Areas of the Gulf of Mexico (NMFS, 2007). With implementation of the mitigation 

measures in NTL 2012-JOINT-G01, NMFS concluded that the likelihood of collisions between 

vessels and sperm whales would be reduced to insignificant levels. NMFS concluded that the 

observed avoidance of passing vessels by sperm whales is an advantageous response to avoid a 

potential threat and is not expected to result in any significant effect on migration, breathing, 

nursing, breeding, feeding, or sheltering to individuals, or have any consequences at the level of 

the population. With implementation of the vessel strike avoidance measures requirement to 

maintain a distance of 295 ft (90 m) from sperm whales, NMFS concluded that the potential for 

harassment of sperm whales would be reduced to discountable levels. 

Helicopter traffic also has the potential to disturb sperm whales. Smultea et al. (2008) 

documented responses of sperm whales offshore Hawaii to fixed wing aircraft flying at an 

altitude of 800 ft (245 m). A reaction to the initial pass of the aircraft was observed during 

3 (12%) of 24 sightings. All three reactions consisted of a hasty dive and occurred at less than 

1,180 ft (360 m) lateral distance from the aircraft. Additional reactions were seen when aircraft 

circled certain whales to make further observations. Based on other studies of cetacean 

responses to sound, the authors concluded that the observed reactions to brief overflights by 

the aircraft were short-term and probably of no long-term biological significance. 

Helicopters maintain altitudes above 700 ft (213 m) during transit to and from the offshore 

working area. In the event that a whale is seen during transit, the helicopter will not approach 

or circle the animal(s). In addition, guidelines and regulations specify that helicopters maintain 

an altitude of 1,000 ft (305 m) within 300 ft (91 m) of marine mammals (BOEM, 2012a,b). 

Although whales may respond to helicopters (Smultea et al., 2008), NMFS (2007) and 

BOEM (2012a) concluded that this altitude would minimize the potential for disturbing sperm 

whales. Therefore, no significant impacts are expected. 

Impacts of a Small Fuel Spill 

Potential spill impacts on marine mammals including sperm whales are discussed in 

MMS (2007b) and BOEM (2012b,d) 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). 

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Oil impacts on marine mammals are discussed by Geraci and St. Aubin (1990). For this EP, there 

are no unique site-specific issues with respect to spill impacts on these animals. 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations, including fuel transfer. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the potential for impacts on sperm whales. EP Section 9b

provides detail on spill response measures. Given the open ocean location of the lease area and 

the duration of a small spill, the opportunity for impacts to occur would be very brief. 

A small fuel spill in offshore waters would produce a slick on the water surface and increase the 

concentrations of petroleum hydrocarbons and their degradation products. The extent and 

persistence of impacts would depend on the meteorological and oceanographic conditions at 

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that more than 90% would be evaporated or dispersed 

naturally within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 

12 ac (0.5 to 5 ha), depending on sea state and weather conditions. 

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation, 

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of 

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and 

noise of response vessels and aircraft (Marine Mammal Commission [MMC], 2011). However, 

due to the limited areal extent and short duration of water quality impacts from a small fuel 

spill, as well as the mobility of sperm whales, no significant impacts would be expected. 

Impacts of a Large Oil Spill 

Potential spill impacts on marine mammals including sperm whales are discussed in 

MMS (2007b), BOEM (2012a,b,d), and in NMFS (2007). Oil impacts on marine mammals are 

discussed by Geraci and St. Aubin (1990). For this EP, there are no unique site-specific issues 

with respect to spill impacts on these animals. 

Impacts of oil spills on sperm whales can include direct impacts from oil exposure, as well as 

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and 

dispersants) (MMC, 2011). Direct physical and physiological effects can include skin irritation, 

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of 

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey; and stress from 

the activities and noise of response vessels and aircraft. The level of impact of oil exposure 

depends on the amount, frequency, and duration of exposure; route of exposure; and type or 

condition of petroleum compounds or chemical dispersants (Waring et al., 2013). Complications 

of the above may lead to dysfunction of immune and reproductive systems, physiological stress, 

declining physical condition, and death. Behavioral responses can include displacement of 

animals from prime habitat, disruption of social structure, changing prey availability and 

foraging distribution and/or patterns, changing reproductive behavior/productivity, and 

changing movement patterns or migration (MMC, 2011). Ackleh et al. (2012) hypothesized that 

sperm whales may have temporarily relocated away from areas near the Macondo spill in 2010. 

In the event of a large spill, the level of vessel and aircraft activity associated with spill response 

could disturb sperm whales and potentially result in vessel strikes, entanglement, or other injury 

or stress. Response vessels would operate in accordance with NTL 2012-JOINT-G01 to reduce 

the potential for striking or disturbing these animals. 

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A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on sperm whales are expected. 

C.3.2 Florida Manatee (Endangered) 

Most of the Gulf of Mexico manatee population is located in peninsular Florida (USFWS, 2001). 

Manatees regularly migrate farther west of Florida in the warmer months (Wilson, 2003) into 

Alabama and Louisiana coastal environs, with some individuals traveling as far west as Texas 

(Fertl et al., 2005). A species description is presented in MMS (2007b) and in the recovery plan 

for this species (USFWS, 2001). 

IPFs that could potentially affect manatees include support vessel and helicopter traffic and a 

large oil spill. A small fuel spill in the lease area would be unlikely to affect manatees, as the 

lease area is approximately 55 miles (89 km) from the nearest shoreline (Louisiana). 

As explained in Section A.9.2, a small fuel spill would not be expected to make landfall or reach 

coastal waters prior to breaking up. Compliance with NTL 2012-BSEE-G01 will minimize the 

potential for marine debris-related impacts on manatees. Consistent with the analysis in 

BOEM (2012a), impacts of routine project-related activities on the manatee would be negligible. 

Impacts of Support Vessel and Helicopter Traffic 

Support vessel traffic has the potential to disturb manatees, and there is also a risk of vessel 

strikes, which are identified as a threat in the recovery plan for this species (USFWS, 2001). 

To reduce the potential for vessel strikes, the BOEM has issued NTL 2012-JOINT-G01, which 

recommends protected species identification training and that vessel operators and crews 

maintain a vigilant watch for marine mammals and slow down or stop their vessel to avoid 

striking protected species, and requires operators to report sightings of any injured or dead 

protected species. Compliance with NTL 2012-JOINT-G01 will minimize the likelihood of vessel 

strikes, and no significant impacts on manatees are expected. 

Helicopter traffic, if present, also has the potential to disturb manatees. Rathbun (1988) 

reported that manatees were disturbed more by helicopters than by fixed-wing aircraft; 

however, the helicopter was flown at relatively low altitudes of 66 to 525 ft (20 to 160 m). 

Helicopters used in support operations maintain a minimum altitude of 700 ft (213 m) while in 

transit offshore, 1,000 ft (305 m) over unpopulated areas or across coastlines, and 2,000 ft 

(610 m) over populated areas and sensitive habitats such as wildlife refuges and park properties. 

In addition, guidelines and regulations specify that helicopters maintain an altitude of 1,000 ft 

(305 m) within 300 ft (91 m) of marine mammals (BOEM, 2012a,b). This mitigation measure will 

minimize the potential for disturbing manatees, and no significant impacts are expected. 

Impacts of a Large Oil Spill 

The OSRA results summarized in Table 3 predict that some Texas, Louisiana, and Florida 

shorelines could be contacted by a large oil spill within 30 days. There is no critical habitat 

designated in these areas, and the number of manatees potentially present is a small fraction of 

the population in peninsular Florida. 

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In the event that manatees were exposed to oil, effects could include direct impacts from oil 

exposure, as well as indirect impacts due to response activities and materials (e.g., vessel traffic, 

noise, and dispersants) (MMC, 2011). Direct physical and physiological effects can include skin 

irritation, inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; 

inhalation of toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey 

(or contaminated vegetation, in the case of manatees); and stress from the activities and noise 

of response vessels and aircraft. Complications of the above may lead to dysfunction of immune 

and reproductive systems, physiological stress, declining physical condition, and death. 

Behavioral responses can include displacement of animals from prime habitat, disruption of 

social structure, changing prey availability and foraging distribution and/or patterns, changing 

reproductive behavior/productivity, and changing movement patterns or migration 

(MMC, 2011). 

In the event that a large spill reached coastal waters where manatees were present, the level of 

vessel and aircraft activity associated with spill response could disturb manatees and potentially 

result in vessel strikes, entanglement, or other injury or stress. Response vessels would operate 

in accordance with NTL 2012-JOINT-G01 to reduce the potential for striking or disturbing these 

animals, and therefore no significant impacts are expected. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on manatees are expected. 

C.3.3 Endangered Mysticete Whales 

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right 

whale, and sei whale) have also been reported from the Gulf of Mexico, but are considered rare 

or extralimital there (Würsig et al., 2000). No critical habitat has been designated for these 

species in the Gulf of Mexico. 

Due to the rare occurrence of these whales in the Gulf of Mexico, it is unlikely that any 

endangered mysticete would come into contact with any project activities, either routine 

operations or accidents. 

Mysticete whales were not included as affected species in the Biological Opinion for the 

Five-Year Oil and Gas Leasing Program in the Central and Western Planning Areas of the Gulf of 

Mexico (NMFS, 2007). Potential impacts analyzed in MMS (2007b) and BOEM (2012a,b,d) are 

incorporated by reference. If any of these whales were present in the area, potential impacts 

would be the same as those discussed in Section C.3.4. 

C.3.4 Non-Endangered Marine Mammals (Protected) 

In addition to the seven endangered species that have been cited previously, 22 additional 

species of marine mammals may be found in the Gulf of Mexico, including 2 species of 

mysticete whales, the dwarf and pygmy sperm whales, 4 species of beaked whales, and 

14 species of delphinids (see EP Section 6h). All marine mammals are protected species under 

the MMPA. The most common non-endangered cetaceans in the deepwater environment are 

odontocetes such as the pantropical spotted dolphin, spinner dolphin, and Clymene dolphin. 

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A brief summary is presented in this section, and additional information on these groups is 

presented in MMS (2007b). 

Mysticete whales. Two species of non-endangered mysticete whales are known from the 

Gulf of Mexico: the Bryde’s whale (Balaenoptera edeni) and minke whale 

(Balaenoptera acutorostrata). The Bryde’s whale (Balaenoptera edeni) has been sighted most 

frequently along the 328-ft (100-m) isobath (Davis and Fargion, 1996; Davis et al., 2000). Most 

sightings have been made in the DeSoto Canyon region and off western Florida, although there 

have been some in the west-central portion of the northeastern Gulf. The minke whale is 

considered rare in the Gulf of Mexico, with the only confirmed records coming from strandings 

(Würsig et al., 2000). Based on the available data, it is possible that Bryde’s whales could occur 

in the lease area. 

Dwarf and pygmy sperm whales. At sea, it is difficult to differentiate dwarf sperm whales 

(Kogia sima) from pygmy sperm whales (Kogia breviceps), and sightings are often grouped 

together as “Kogia spp.” Both species have a worldwide distribution in temperate to tropical 

waters. In the Gulf of Mexico, both species occur primarily along the continental shelf edge and 

in deeper waters off the continental shelf (Mullin et al., 1991; Mullin, 2007; Waring et al., 2013). 

Either species could occur in the lease area. 

Beaked whales. Four species of beaked whales are known from the Gulf of Mexico. They are 

Blainville’s beaked whale (Mesoplodon densirostris), Cuvier’s beaked whale (Ziphius cavirostris), 

Sowerby’s beaked whale (Mesoplodon bidens), and Gervais’ beaked whale 

(Mesoplodon europaeus). Stranding records in the Gulf of Mexico suggest that Gervais’ beaked 

whale is the most common, and Sowerby’s beaked whale is extralimital. Due to the difficulties 

of at-sea identification, beaked whales in the Gulf of Mexico are identified either as 

Cuvier’s beaked whales or are grouped into an undifferentiated complex (Mesoplodon spp. and 

Ziphius spp.). In the northern Gulf of Mexico, they are broadly distributed in waters greater 

than 3,281 ft (1,000 m) over lower slope and abyssal landscapes (Davis et al., 2000). Any of 

these species could occur in the lease area (Waring et al., 2013).

Delphinids. Fourteen species of delphinids are known from the Gulf of Mexico, including 

Atlantic spotted dolphin (Stenella frontalis), bottlenose dolphin (Tursiops truncatus), 

Clymene dolphin (Stenella clymene), false killer whale (Pseudorca crassidens), Fraser’s dolphin 

(Lagenodelphis hosei), killer whale (Orcinus orca), melon-headed whale (Peponocephala electra), 

pantropical spotted dolphin (Stenella attenuata), pygmy killer whale (Feresa attenuata), 

short-finned pilot whale (Globicephala macrorhynchus), Risso’s dolphin (Grampus griseus), 

rough-toothed dolphin (Steno bredanensis), spinner dolphin (Stenella longirostris), and striped 

dolphin (Stenella coeruleoalba). The most common non-endangered cetaceans in the 

deepwater environment are the pantropical spotted dolphin, spinner dolphin, and 

Clymene dolphin. However, any of these species could occur in the lease area 

(Waring et al., 2013). 

The bottlenose dolphin (Tursiops truncatus) is a common inhabitant of the northern Gulf of 

Mexico, particularly within continental shelf waters. There are two ecotypes of bottlenose 

dolphins, a coastal form and an offshore form, which are genetically isolated from each other 

(Waring et al., 2013). The offshore form of the bottlenose dolphin may occur within the lease 

area. Inshore populations of coastal bottlenose dolphins in the northern Gulf of Mexico are 

separated by the NMFS into 37 geographically distinct population units, or stocks, for 

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management purposes (Waring et al., 2013). NMFS (2013) has proposed to classify the Gulf of 

Mexico Northern Coastal Stock, Western Coastal Stock, and all 32 of the Bay, Sound, and 

Estuarine Stocks as strategic stocks. A “strategic” stock is defined by the MMPA as a marine 

mammal stock 

 for which the level of direct human-caused mortality exceeds the potential biological 

removal level; 

 which, based on the best available scientific information, is declining and is likely to be listed 

as a threatened species under the ESA within the foreseeable future; or 

 which is listed as a threatened or endangered species under the ESA, or is designated as 

depleted under the MMPA. 

The strategic stock designation in this case was based primarily on the occurrence of an 

“Unusual Mortality Event” (UME) of unprecedented size and duration that has affected these 

stock areas. This UME began in February 2010 and, as of early 2012, the event was still 

considered to be ongoing (Waring et al., 2013). Carmichael et al. (2012) hypothesized that the 

unusual number of bottlenose dolphin strandings in the northern Gulf of Mexico during this 

time may have been associated with environmental perturbations, including sustained cold 

weather and the Macondo spill in 2010, as well as large volumes of cold freshwater discharge in 

the early months of 2011. 

IPFs that could potentially affect non-endangered marine mammals include drilling rig presence, 

noise, and lights; support vessel and helicopter traffic; and two types of accidents (a small fuel 

spill and a large oil spill). Effluent discharges are likely to have negligible impacts on marine 

mammals due to rapid dispersion, the small area of ocean affected, the intermittent nature of 

the discharges, and the mobility of marine mammals. Compliance with NTL 2012-BSEE-G01 will 

minimize the potential for marine debris-related impacts on marine mammals. 

Impacts of Drilling Rig Presence, Noise, and Lights 

Noise from routine drilling activities has the potential to disturb marine mammals. Most 

odontocetes (toothed whales and dolphins) use higher frequency sounds than those produced 

by OCS drilling activities (Richardson et al., 1995). Noise associated with drilling is relatively 

weak in intensity, and an individual animal’s noise exposure would be transient. Stronger noise 

levels will occur during thruster use in dynamic positioning. Thruster noise impacts would be 

expected at greater distances than vessel noise alone (LGL Ecological Research Associates, Ltd., 

2006) but are dependent on variables relating to thruster type and usage. It is expected that 

marine mammals within or near the lease area would be able to detect the presence of the 

drilling rig and avoid exposure to higher energy sounds, particularly within an open ocean 

environment. 

Some odontocetes have shown increased feeding activity around lighted platforms at night 

(Todd et al., 2009). Even temporary drilling rigs present an attraction to pelagic food sources 

that may attract cetaceans (and sea turtles). Therefore, prey congregation could pose an 

attraction to protected species that exposes them to higher levels or longer durations of noise 

that might otherwise be avoided. 

There are other OCS facilities and activities near the lease area, and the region as a whole has a 

large number of similar sources. Due to the limited scope, timing, and geographic extent of 

drilling activities, this project would represent a small temporary contribution to the overall 

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noise regime, and any short-term impacts are not expected to be biologically significant to 

marine mammal populations. 

Drilling rig lighting and presence are not identified as IPFs for marine mammals in MMS (2007b) 

or BOEM (2012a,b,d). Therefore, no significant impacts are expected. 

Impacts of Support Vessel and Helicopter Traffic 

Support vessel traffic has the potential to disturb marine mammals, and there is also a risk of 

vessel strikes. Data concerning the frequency of vessel strikes are presented in the lease sale 

EIS (MMS, 2007b). To reduce the potential for vessel strikes, the BOEM and BSEE have issued 

NTL 2012-JOINT-G01, which recommends protected species identification training and that 

vessel operators and crews maintain a vigilant watch for marine mammals and slow down or 

stop their vessel to avoid striking protected species, and requires operators to report sightings 

of any injured or dead protected species. Vessel operators and crews are required to attempt to 

maintain a distance of 300 ft (91 m) or greater when whales are sighted and 150 ft (45 m) when 

small cetaceans are sighted. When cetaceans are sighted while a vessel is underway, vessels 

must attempt to remain parallel to the animal’s course and avoid excessive speed or abrupt 

changes in direction until the cetacean has left the area. Vessel operators are required to 

reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large assemblages of 

cetaceans are observed near an underway vessel, when safety permits. Compliance with this 

NTL will minimize the likelihood of vessel strikes as well as reduce the chance for disturbing 

marine mammals, and therefore no significant impacts are expected. 

Aircraft traffic also has the potential to disturb marine mammals (Würsig et al., 1998). However, 

while flying offshore, helicopters maintain altitudes above 700 ft (213 m) during transit to and 

from the working area. In addition, guidelines and regulations specify that helicopters maintain 

an altitude of 1,000 ft (305 m) within 300 ft (91 m) of marine mammals (BOEM, 2012a,b). This 

altitude will minimize the potential for disturbing marine mammals, and no significant impacts 

are expected (BOEM, 2012a,b). 

Impacts of a Small Fuel Spill 

Potential spill impacts on marine mammals are discussed in MMS (2007b) and BOEM 

(2012a,b,d), and oil impacts on marine mammals in general are discussed in Geraci and St. Aubin 

(1990). For this EP, there are no unique site-specific issues with respect to spill impacts on these 

animals. 

The probability of a fuel spill will be minimized by Shell’s preventative measures, including fuel 

transfer. In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate 

and reduce the potential for impacts on marine mammals. EP Section 9b provides detail on spill 

response measures. Given the open ocean location of the lease area and the duration of a small 

spill, the opportunity for impacts to occur would be very brief. 

A small fuel spill in offshore waters would produce a slick on the water surface and increase the 

concentrations of petroleum hydrocarbons and their degradation products. The extent and 

persistence of impacts would depend on the meteorological and oceanographic conditions at 

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally 

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within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 12 ac 

(0.5 to 5 ha), depending on sea state and weather conditions. 

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation, 

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of 

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and 

noise of response vessels and aircraft (MMC, 2011). However, due to the limited areal extent 

and short duration of water quality impacts from a small fuel spill, as well as the mobility of 

marine mammals, no significant impacts would be expected. 

Impacts of a Large Oil Spill 

Potential spill impacts on marine mammals are discussed in MMS (2007b), BOEM (2012a,b,d), 

and in Geraci and St. Aubin (1990). For this EP, there are no unique site-specific issues. 

Impacts of oil spills on marine mammals can include direct impacts from oil exposure, as well as 

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and 

dispersants) (MMC, 2011). Direct physical and physiological effects can include skin irritation, 

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of 

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey 

(or contaminated vegetation, in the case of manatees); and stress from the activities and noise 

of response vessels and aircraft. Complications of the above may lead to dysfunction of immune 

and reproductive systems, physiological stress, declining physical condition, and death. 

Behavioral responses can include displacement of animals from prime habitat; disruption of 

social structure; changing prey availability and foraging distribution and/or patterns; changing 

reproductive behavior/productivity; and changing movement patterns or migration 

(MMC, 2011). 

In the event of a large spill, the level of vessel and aircraft activity associated with spill response 

could disturb marine mammals and potentially result in vessel strikes, entanglement, or other 

injury or stress. Response vessels would operate in accordance with NTL 2012-JOINT-G01 to 

reduce the potential for striking or disturbing these animals, and therefore no significant 

impacts are expected. A blowout resulting in a large oil spill is an extremely rare event, and the 

probability of such an event will be minimized by Shell’s well control and blowout prevention 

measures as detailed in EP Section 2j. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the impacts. EP Section 9b provides detail on spill 

response measures. Therefore, no significant spill impacts on marine mammals are expected. 

C.3.5 Sea Turtles (Endangered/Threatened) 

As listed in EP Section 6h, five species of endangered or threatened sea turtles may be found 

near the lease area. Endangered species are the leatherback (Dermochelys coriacea), 

Kemp's ridley (Lepidochelys kempii), and hawksbill (Eretmochelys imbricata) turtles. The distinct 

population segment (DPS) of loggerhead turtle (Caretta caretta) that occurs in the 

Gulf of Mexico is listed as threatened, although other DPSs are endangered. The green turtle 

(Chelonia mydas) is listed as threatened, except for the Florida breeding population, which is 

listed as endangered. Species descriptions are presented in MMS (2007b). 

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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 – Loggerhead turtles 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 nesting site of the Kemp’s ridley turtle is Rancho Nuevo 

beach, Tamaulipas, Mexico (NMFS et al., 2011). Approximately 200 Kemp’s ridley turtles 

nested on Texas beaches in 2009 (Sea Turtle Restoration Project, 2011). Kemp’s ridley 

turtles typically do not nest anywhere near the project area, although there have been 

occasional reports of nesting in Alabama (Share the Beach, 2010); and 

 Hawksbill turtles – Hawksbill turtles typically do not nest anywhere near the project area. 

IPFs that could potentially affect sea turtles include drilling rig presence, noise, and lights; 

support vessel and helicopter traffic; and two types of accidents – a small fuel spill and a large 

oil spill. Effluent discharges are likely to have negligible impacts on sea turtles due to rapid 

dispersion, the small area of ocean affected, and the intermittent nature of the discharges. 

Compliance with NTL 2012-BSEE-G01 will minimize the potential for marine debris-related 

impacts on sea turtles. 

Impacts of Drilling Rig Presence, Noise, and Lights 

Offshore drilling activities produce a broad array of sounds at frequencies and intensities that 

may be detected by sea turtles (Geraci and St. Aubin, 1987). Potential impacts may include 

behavioral disruption and temporary or permanent displacement from the area near the sound 

source. Certain sea turtles, especially loggerheads, may be attracted to offshore structures 

(Lohoefener et al., 1990) and, thus, may be more susceptible to impacts from sounds produced 

during routine operations. Helicopters and service vessels may also affect sea turtles due to 

machinery noise and/or visual disturbances. The most likely impacts would be short-term 

behavioral changes such as diving and evasive swimming, disruption of activities, or departure 

from the area. Due to the limited scope, timing, and geographic extent of drilling activities, 

these short-term impacts are not expected to be biologically significant to sea turtle 

populations. 

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Artificial lighting can disrupt the nocturnal orientation of sea turtle hatchlings (Witherington, 

1997; Tuxbury and Salmon, 2005). However, hatchlings may rely less on light cues when they 

are offshore than when they are emerging on the beach (Salmon and Wyneken, 1990). 

NMFS (2007) concluded that the effects of lighting from offshore structures on sea turtles are 

insignificant. Therefore, no significant impacts are expected. 

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sea turtles, and there is also a risk of vessel 

strikes. Data show that vessel traffic is one cause of sea turtle mortality in the Gulf of Mexico 

(Lutcavage et al., 1997). While adult sea turtles are visible at the surface during the day and in 

clear weather, they can be difficult to spot from a moving vessel when resting below the water 

surface, during nighttime, or during periods of inclement weather. To reduce the potential for 

vessel strikes, the BOEM and BSEE have issued NTL 2012-JOINT-G01, which recommends 

protected species identification training and that vessel operators and crews maintain a vigilant 

watch for sea turtles and slow down or stop their vessel to avoid striking protected species, and 

requires operators to report sightings of any injured or dead protected species. When sea 

turtles are sighted, vessel operators and crews are required to attempt to maintain a distance of 

150 ft (45 m) or greater whenever possible. Compliance with this NTL will minimize the 

likelihood of vessel strikes as well as reduce the chance for disturbing sea turtles (NMFS, 2007). 

Therefore, no significant impacts are expected. 

Helicopter traffic also has the potential to disturb sea turtles. However, while flying offshore, 

helicopters maintain altitudes above 700 ft (213 m) during transit to and from the working area. 

This altitude will minimize the potential for disturbing sea turtles, and no significant impacts are 

expected. 

Impacts of a Small Fuel Spill 

Potential spill impacts on sea turtles are discussed in MMS (2007b), BOEM (2012b,d), and in 

NMFS (2007) in its Biological Opinion for the Five-Year Oil and Gas Leasing Program in the 

Central and Western Planning Areas of the Gulf of Mexico. For this EP, there are no unique 

site-specific issues with respect to spill impacts on these animals. 

The probability of a fuel spill will be minimized by Shell’s preventative measures, including fuel 

transfer. In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate 

and reduce the potential for impacts on sea turtles. EP Section 9b provides detail on spill 

response measures. Given the open ocean location of the lease area, the duration of a small 

spill and opportunity for impacts to occur would be very brief. 

A small fuel spill in offshore waters would produce a slick on the water surface and increase the 

concentrations of petroleum hydrocarbons and their degradation products. The extent and 

persistence of impacts would depend on the meteorological and oceanographic conditions at 

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that more than 90% would be evaporated or dispersed 

naturally within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 

12 ac (0.5 to 5 ha), depending on sea state and weather conditions. 

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Direct physical and physiological effects of exposure to diesel fuel could include skin irritation, 

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of 

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and 

noise of response vessels and aircraft (MMS, 2007b; NMFS, 2010b; BOEM, 2012b,d). However, 

due to the limited areal extent and short duration of water quality impacts from a small fuel 

spill, no significant impacts would be expected. 

A small fuel spill in the lease area would be unlikely to affect sea turtle nesting beaches because 

the lease area is 55 miles (89 km) from the nearest shoreline (Louisiana). As explained in 

Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters 

prior to breaking up. 

Impacts of a Large Oil Spill 

Impacts of oil spills on sea turtles can include direct impacts from oil exposure, as well as 

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, dispersants, 

and beach cleanup activities). Direct physical and physiological effects can include skin 

irritation, inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; 

inhalation of toxic fumes and smoke (e.g., from in situ burning of oil); ingestion of oil (and 

dispersants) directly or via contaminated food; and stress from the activities and noise of 

response vessels and aircraft. Complications of the above may lead to dysfunction of immune 

and reproductive systems, physiological stress, declining physical condition, and death. 

Behavioral responses can include displacement of animals from prime habitat, disruption of 

social structure, changing food availability and foraging distribution and/or patterns, changing 

reproductive behavior/productivity, and changing movement patterns or migration 

(MMS, 2007b; NMFS, 2010c). In the unlikely event of a spill, implementation of Shell’s OSRP is 

expected to mitigate and reduce the potential for these types of impacts on sea turtles. 

EP Section 9b provides detail on spill response measures. 

Studies of oil effects on loggerheads in a controlled setting (Lutcavage et al., 1995) suggest that 

sea turtles show no avoidance behavior when they encounter an oil slick, and any sea turtle in 

an affected area would be expected to be exposed. Sea turtles’ diving behaviors also put them 

at risk. Sea turtles rapidly inhale a large volume of air before diving and continually resurface 

over time, which may result in repeated exposure to volatile vapors and oiling (NMFS, 2007). 

The OSRA results summarized in Table 3 predict that some shorelines that support sea turtle 

nesting could be contacted within 30 days. The nearest significant nesting area of loggerhead 

turtles is found on beaches within the Breton NWR. Spilled oil reaching sea turtle nesting 

beaches could have effects on nesting sea turtles and egg development (NMFS, 2007). An oiled 

beach could affect nest site selection or result in no nesting at all (e.g., false crawls). Upon 

hatching and successfully reaching the water, hatchlings are subject to the same types of oil spill 

exposure hazards as adults. Hatchlings that contact oil residues while crossing a beach can 

exhibit a range of effects, from acute toxicity to impaired movement and normal bodily 

functions (NMFS, 2007). 

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. 

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NOAA’s Office of Response and Restoration prepared guidelines in 2007 to minimize impacts to 

nesting activities and existing nests due to beach cleanup activities (Shigenaka et al., 2010). Oil 

spill cleanup activities on the beach (e.g., raking, shoveling, use of mechanical equipment) may 

adversely affect sea turtle nesting activity or existing beach nests. Response workers and 

vehicles may crush eggs and compact beach sand, making it difficult or impossible for hatchlings 

to emerge or for females to use for nesting (Shigenaka et al., 2010). Nighttime human activity 

can prevent sea turtles from coming ashore, may cause females to stop nesting and return to 

the ocean, disorient or impede emerging hatchlings, and crush hatchlings attempting to reach 

the ocean. Locating and marking turtle nests with a 10-ft (3-m) buffer zone to aid in avoiding 

and minimizing impacts is recommended during beach cleanup activities; mechanical equipment 

and hand tools should not be used within the buffer area (USFWS, n.d.). 

Impacts to sea turtles from a large oil spill and associated cleanup activities would be dependent 

upon spill extent, duration, and season (relative to turtle nesting season); the amount of oil 

reaching the shore; the importance of specific beaches to sea turtle nesting; and the level of 

cleanup vessel and beach crew activity required. A blowout resulting in a large oil spill is an 

extremely rare event, and the probability of such an event will be minimized by Shell’s well 

control and blowout prevention measures as detailed in EP Section 2j. In the unlikely event of a 

spill, implementation of Shell’s OSRP would mitigate and reduce direct and indirect impacts to 

turtles from oil exposure and response activities and materials. EP Section 9b provides detail on 

spill response measures. Adherence to the requirements of NTL 2012-JOINT-G01 and general 

guidance regarding beach cleanup activities (Shigenaka et al., 2010; USFWS, n.d.) is expected to 

minimize potential impacts to sea turtles both at sea and on shore. 

C.3.6 Piping Plover (Threatened) 

The Piping Plover (Charadrius melodus) is a migratory shorebird that overwinters along the 

southeastern U.S. and Gulf of Mexico coasts. This threatened species is in decline as a result of 

hunting, habitat loss and modification, predation, and disease (USFWS, 2003). Critical 

overwintering habitat has been designated, including beaches in Texas, Louisiana, Mississippi, 

Alabama, and Florida (Figure 1). Piping Plovers inhabit coastal sandy beaches and mudflats, 

feeding by probing for invertebrates at or just below the surface. They use beaches adjacent to 

foraging areas for roosting and preening (USFWS, 2010a). A species description is presented in 

MMS (2007b). 

A large oil spill is the only IPF that could potentially affect Piping Plovers. There are no IPFs 

associated with routine project activities that could affect these birds. A small fuel spill in the 

lease area would be unlikely to affect Piping Plovers because a small fuel spill would not be 

expected to make landfall or reach coastal waters prior to breaking up (see explanation in 

Section A.9.2).

Impacts of a Large Oil Spill 

The lease area is 58 miles (93 km) from the nearest shoreline inhabited by Piping Plovers. The 

OSRA results summarized in Table 3 predict that Texas and Louisiana shorelines designated as 

critical habitats for the wintering Piping Plover could be contacted by a spill within 30 days. 

Plaquemines Parish, Louisiana, which has the highest probability of contact for the 30-day 

interval (8%), includes critical habitat of Piping Plovers. 

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Figure 1. Location of selected environmental features in relation to the lease area. 

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Plovers could become externally oiled while foraging on oiled shores or be exposed internally 

through ingestion of oiled intertidal sediments and prey (MMS, 2007b). Plovers congregate and 

feed along tidally exposed banks and shorelines, following the tide out and foraging at the 

water’s edge. It is possible that some deaths of Piping Plovers could occur, especially if spills 

occur during winter months when plovers are most common along the coastal Gulf or if spills 

contacted critical habitat. Impacts could also occur from vehicular traffic on beaches and other 

activities associated with spill cleanup. Shell has extensive resources available to protect and 

rehabilitate wildlife in the event of a spill reaching the shoreline, as detailed in the OSRP. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on Piping Plovers are expected. 

C.3.7 Whooping Crane (Endangered) 

The Whooping Crane (Grus americana) is an omnivorous wading bird and an endangered 

species. There are three wild populations in North America (National Wildlife Federation, 2012). 

One population winters along the Texas coast at Aransas NWR and summers at Wood Buffalo 

National Park in Canada. This population represents the majority of the world’s population of 

free-ranging Whooping Cranes and reached a record population of 278 at Aransas/Wood Buffalo 

National Park in August 2011 (Whooping Crane Eastern Partnership, 2012). A non-migrating 

population has been reintroduced in central Florida, and another reintroduced population 

summers in Wisconsin and migrates to the southeastern U.S. for the winter. Whooping Cranes 

breed, migrate, winter, and forage in a variety of habitats, including coastal marshes and 

estuaries, inland marshes, lakes, ponds, wet meadows and rivers, and agricultural fields 

(USFWS, 2007). About 22,240 ac (9,000 ha) of salt flats on Aransas NWR and adjacent islands 

comprise the principal wintering grounds of the Whooping Crane. Aransas NWR is designated as 

critical habitat for the species (Figure 1). A species description is presented in MMS (2007b) and 

BOEM (2012b,d). 

A large oil spill is the only IPF that could potentially affect Whooping Cranes due to the distance 

from Aransas NWR. 

Impacts of a Large Oil Spill 

A large oil spill has a low probability of affecting Whooping Cranes because the lease area is 

approximately 447 miles (719 km) from its critical habitat (Aransas NWR, Texas) and the 

likelihood of contact with the habitat is extremely low (BOEM, 2012b). 

In the event of oil exposure, Whooping Cranes could become externally oiled while foraging in 

oiled areas or internally exposed to oil through ingestion of contaminated shellfish, frogs, and 

fishes. It is possible that some death of Whooping Cranes could occur. Shell has extensive 

resources available to protect and rehabilitate wildlife in the event of a spill reaching the 

shoreline, as detailed in the OSRP. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

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reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on Whooping Cranes are expected. 

C.3.8 Gulf Sturgeon (Threatened) 

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is a threatened fish species that inhabits major 

rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida 

(Barkuloo, 1988; Wakeford, 2001). An anadromous fish that migrates from the sea upstream 

into coastal rivers to spawn in freshwater, it historically ranged from the Mississippi River to 

Charlotte Harbor, Florida (Wakeford, 2001). Today, this range has contracted to encompass 

major rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida. 

Populations have been depleted or even extirpated throughout this range by fishing, shoreline 

development, dam construction, water quality changes, and other factors (Barkuloo, 1988; 

Wakeford, 2001). These declines prompted the listing of the Gulf sturgeon as a threatened 

species in 1991. The best known populations occur in the Apalachicola and Suwannee Rivers in 

Florida (Carr, 1996; Sulak and Clugston, 1998), the Choctawhatchee River in Alabama 

(Fox et al., 2000), and the Pearl River in Mississippi/Louisiana (Morrow et al., 1998). Critical 

habitat in the Gulf extends from Lake Borgne, Louisiana (St. Bernard Parish), to Suwannee 

Sound, Florida (Levy County) (NMFS, 2010d) (Figure 1). A species description is presented in 

MMS (2007b) and in the recovery plan for this species (USFWS and Gulf States Marine Fisheries 

Commission, 1995). 

A large oil spill is the only IPF that could potentially affect Gulf sturgeon. There are no IPFs 

associated with routine project activities that could affect this species. A small fuel spill in the 

lease area would be unlikely to affect Gulf sturgeon, because a small fuel spill would not be 

expected to make landfall or reach coastal waters prior to breaking up (see explanation in 

Section A.9.2). 

Impacts of a Large Oil Spill 

Potential spill impacts on Gulf sturgeon are discussed in MMS (2007b), BOEM (2012b,d), and in

NMFS (2007) in its Biological Opinion for the Five-Year Oil and Gas Leasing Program in the 

Central and Western Planning Areas of the Gulf of Mexico. For this EP, there are no unique 

site-specific issues with respect to this species. 

The lease area is about 122 miles (196 km) from the nearest Gulf sturgeon critical habitat. 

OSRA modeling (Table 3) predicts that a spill in the lease area would have a 1% chance of 

contacting Gulf sturgeon critical habitat in coastal areas of Okaloosa County, Florida, within 

30 days. In the event of oil reaching Gulf sturgeon habitat, the fish could be affected by direct 

ingestion, ingestion of oiled prey, or the absorption of dissolved petroleum products through 

the gills. Based on the life history of this species, subadult and adult Gulf sturgeon would be 

most vulnerable to a marine oil spill, and would be vulnerable only during winter months (from 

September 1 through April 30) when this species is foraging in estuarine and marine habitats 

(NMFS, 2007). 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. Shell has extensive resources available to protect coastal and estuarine 

wildlife and habitats in the event of a spill reaching the shoreline, as detailed in the OSRP. 

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EP Section 9b provides detail on spill response measures. Therefore, no significant spill impacts 

on Gulf sturgeon are expected. 

C.3.9 Beach Mice (Endangered) 

Four subspecies of endangered beach mouse (Peromyscus polionotus) occur on the barrier 

islands of Alabama and the Florida Panhandle. They are the Alabama, Choctawhatchee, 

Perdido Key, and St. Andrew beach mouse. Critical habitat has been designated for all four 

subspecies; Figure 1 shows the critical habitat combined for all four subspecies. Species 

descriptions are provided in MMS (2007b). 

A large oil spill is the only IPF that could potentially affect subspecies of beach mouse. There are 

no IPFs associated with routine project activities that could affect these animals due to the 

distance from shore and the lack of onshore support activities near their habitat. 

Impacts of a Large Oil Spill 

Potential spill impacts on beach mice are discussed in MMS (2007b) and BOEM (2012b,d). For 

this EP, there are no unique site-specific issues with respect to these species. 

The lease area is about 157 miles (253 km) from the nearest beach mouse critical habitat. 

OSRA modeling predicts that a spill in the lease area would have a 1% chance of contacting 

beach mouse critical habitat in Okaloosa County, Florida, within 30 days. In the event of oil 

contacting these beaches, beach mice could experience several types of direct and indirect 

impacts. Contact with spilled oil could cause skin and eye irritation and subsequent infection; 

matting of fur; irritation of sweat glands, ear tissues, and throat tissues; disruption of sight and 

hearing; asphyxiation from inhalation of fumes; and toxicity from ingestion of oil and 

contaminated food. Indirect impacts could include reduction of food supply, destruction of 

habitat, and fouling of nests. Impacts could also occur from vehicular traffic and other activities 

associated with spill cleanup. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on beach mice are expected. 

C.4 Coastal and Marine Birds 

C.4.1 Marine and Pelagic Birds 

A variety of seabirds may occur in the pelagic environment of the project areas 

(Clapp et al., 1982a,b, 1983; Peake, 1996; Hess and Ribic, 2000). Seabirds spend much of their 

lives offshore over the open ocean, except during breeding season when they nest along the 

coast. In addition, other birds such as waterfowl, marsh birds, and shorebirds may occasionally 

be present over open ocean areas. No endangered or threatened bird species are likely to occur 

at the project area due to the distance from shore. For a discussion of shorebirds and coastal 

nesting birds, see Section C.4.2. 

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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. 

GulfCet II did not estimate bird densities; however, Powers (1987) indicates that seabird 

densities over the open ocean typically are <10 birds/km2. 

Trans-Gulf migrant birds including shorebirds, wading birds, and terrestrial birds may also be 

present in the lease area. Migrant birds may use offshore structures and platforms for resting, 

feeding, or as temporary shelter from inclement weather (Russell, 2005). Some birds may be 

attracted to offshore structures because of the lights and the fish populations that aggregate 

around these structures. 

IPFs that could potentially affect marine and pelagic birds include drilling rig presence, noise, 

and lights; support vessel and helicopter traffic; and two types of accidents – a small fuel spill 

and a large oil spill. Effluent discharges permitted under the NPDES general permit are likely to 

have negligible impacts on the birds due to rapid dispersion, the small area of ocean affected, 

the intermittent nature of the discharges, and the mobility of these animals. Compliance with 

NTL 2012-BSEE-G01 will minimize the potential for marine debris-related impacts on birds. 

Impacts of Drilling Rig Presence, Noise, and Lights 

Birds that frequent platforms may be exposed to contaminants including air pollutants and 

routine discharges, but significant impacts are unlikely due to rapid dispersion of effluents and 

air pollutants. Birds migrating over water have been known to strike offshore structures, 

resulting in death or injury (Wiese et al., 2001; Russell, 2005). Mortality of migrant birds at tall 

towers and other land-based structures has been reviewed extensively, and the mechanisms 

involved in platform collisions appear to be similar. In some cases, migrants simply do not see a 

part of the platform until it is too late. In other cases, navigation may be disrupted by noise 

(Russell, 2005). 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). 

Overall, potential negative impacts to birds from drilling rig lighting, potential collisions, or other 

adverse effects are highly localized, relatively short term and temporary in nature, and may be 

expected to affect only individual birds during migration periods. Therefore, these potential 

impacts are not expected to affect birds at the population or species level and are not significant 

(BOEM, 2012b). 

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Impacts of Support Vessel and Helicopter Traffic 

Support vessels and helicopters are unlikely to significantly disturb pelagic birds in open, 

offshore waters. It is likely that individual birds would experience, at most, only short-term 

behavioral disruption, and the impact would not be significant. 

Impacts of a Small Fuel Spill 

Potential spill impacts on marine birds are discussed in MMS (2007b) and BOEM (2012b,d). For 

this EP, there are no unique site-specific issues with respect to spill impacts on these animals. 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations, including fuel transfer. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the potential for impacts on marine and pelagic birds. 

EP Section 9b provides detail on spill response measures. Given the open ocean location of the 

lease area and the short duration of a small spill, the potential exposure for pelagic marine birds 

would be brief. 

A small fuel spill in offshore waters would produce a slick on the water surface and increase the 

concentrations of petroleum hydrocarbons and their degradation products. The extent and 

persistence of impacts would depend on the meteorological and oceanographic conditions at 

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that more than 90% would be evaporated or dispersed 

naturally within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 

12 ac (0.5 to 5 ha), depending on sea state and weather conditions. 

Birds exposed to oil on the sea surface could experience direct physical and physiological effects 

including skin irritation; chemical burns of skin, eyes, and mucous membranes; and inhalation of 

VOCs. Because of the limited areal extent and short duration of water quality impacts from a 

small fuel spill, secondary impacts due to ingestion of oil via contaminated prey or reductions in 

prey abundance are unlikely. Due to the low densities of birds in open ocean areas, the small 

area affected, and the brief duration of the surface slick, no significant impacts on marine and 

pelagic birds would be expected. 

Impacts of a Large Oil Spill 

Potential spill impacts on marine and pelagic birds are discussed in MMS (2007b) and BOEM 

(2012b,d). For this EP, there are no unique site-specific issues with respect to spill impacts on 

these animals. 

Pelagic seabirds could be exposed to oil from a spill at the project area. Hess and Ribic (2000) 

reported that terns, storm-petrels, shearwaters, and jaegers were the most frequently sighted 

seabirds in the deepwater Gulf of Mexico (>656 ft [>200 m]). Powers (1987) indicates that 

seabird densities over the open ocean typically are <10 birds/km2. The number of pelagic birds 

that could be affected in open, offshore waters would depend on the extent and persistence of 

the oil slick. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

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reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on marine and pelagic birds are expected. 

C.4.2 Shorebirds and Coastal Nesting Birds 

Threatened and endangered bird species (Piping Plover and Whooping Crane) have been 

discussed previously in Section C.3. Various species of non-endangered birds are also found 

along the northern Gulf Coast, including diving birds, shorebirds, marsh birds, wading birds, and 

waterfowl. Gulf Coast marshes and beaches also provide important feeding grounds and 

nesting habitats. Species that nest on beaches, flats, dunes, bars, barrier islands, and similar 

coastal and nearshore habitats include the Sandwich Tern, Wilson’s Plover, Black Skimmer, 

Forster’s Tern, Gull-Billed Tern, Laughing Gull, Least Tern, and Royal Tern (USFWS, 2010b). 

Additional information is presented in MMS (2007b) and BOEM (2012b). 

The Brown Pelican (Pelecanus occidentalis) was delisted from federal endangered status in 2009 

(USFWS, 2010c). However, this species remains listed as endangered by the State of Louisiana 

(State of Louisiana Department of Wildlife and Fisheries, 2013), is listed as a species of greatest 

conservation need by the State of Mississippi (Mississippi Department of Wildlife, Fisheries and 

Parks, 2005), and is designated as a species of special concern by the State of Florida (Florida 

Fish and Wildlife Conservation Commission, 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 that could potentially affect shorebirds and coastal nesting birds include support vessel and 

helicopter traffic and a large oil spill. As explained in Section A.9.2, a small fuel spill would not 

be expected to make landfall or reach coastal waters prior to breaking up. Compliance with 

NTL 2012-BSEE-G01 will minimize the potential for marine debris-related impacts on shorebirds. 

Impacts of Support Vessel and Helicopter Traffic 

Support vessels and helicopters will transit coastal areas near Port Fourchon and Boothville, 

Louisiana, where shorebirds and coastal nesting birds may be found. These activities could 

periodically disturb individuals or groups of birds within sensitive coastal habitats (e.g., wetlands 

that may support feeding, resting, or breeding birds). 

Vessel traffic may disturb some foraging and resting birds. Flushing distances vary among 

species and individuals (Rodgers and Schwikert, 2002). The disturbances will be limited to 

flushing birds away from vessel pathways; known distances are from 65 to 160 ft (20 to 49 m) 

for personal watercraft and 75 to 190 ft (23 to 58 m) for outboard-powered boats (Rodgers and 

Schwikert, 2002). Flushing distances may be similar or less for the support vessels to be used for 

Shell’s project, and some species such as gulls are attracted to boats. Support vessels will not 

approach nesting or breeding areas on the shoreline, so nesting birds, eggs, and chicks will not 

be disturbed. Vessel operators will use designated navigation channels and comply with posted 

speed and wake restrictions while transiting sensitive inland waterways. Due to the limited 

scope, timing, and geographic extent of drilling activities, any short-term impacts are not 

expected to be significant to coastal bird populations. 

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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 (Bélanger and Bédard, 1989). 

The Federal Aviation Administration recommends (Advisory Circular No. 91-36D) that pilots 

maintain a minimum altitude of 2,000 ft (610 m) when flying over noise-sensitive areas such as 

parks, forest, primitive areas, wilderness areas, national seashores, or national wildlife refuges, 

and maintain flight paths to reduce aircraft noise in these noise-sensitive areas. The minimum 

altitude is greater than the distance (slant range) at which aircraft overflights have been 

reported to cause behavioral effects on most species of birds studied in Efroymson et al. (2000). 

It is assumed that adherence to these guidelines would reduce potential behavioral disturbances 

(such as temporary displacement or avoidance behavior) of individual birds in coastal and 

inshore areas. The potential impacts are not expected to be significant to bird populations or 

species in the project area. 

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 by a large oil spill 

within 30 days. 

Coastal birds can be exposed to oil as they float on the water surface, dive during foraging, or 

wade in oiled coastal waters. Oiled birds can lose the ability to fly, dive for food, or float on the 

water, which could lead to drowning (USFWS, 2010d). Oil interferes with the water repellency 

of feathers and can cause hypothermia in the right conditions. As birds groom themselves, they 

can ingest and inhale the oil on their bodies. Scavengers such as Bald Eagles and gulls can be 

exposed to oil by feeding on carcasses of contaminated fish and wildlife. While ingestion can kill 

animals immediately, more often it results in lung, liver, and kidney damage, which can 

eventually lead to death. Bird eggs may be damaged if an oiled adult sits on the nest. 

Studies concerning the Macondo spill provide additional information regarding impacts on 

shorebirds and coastal nesting birds that may be affected in the event that a large oil spill 

reaches coastal habitats. 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. Although 

the Macondo spill had direct and indirect impacts to coastal and marine birds, it is premature to 

conclude impacts over a long period (BOEM, 2012b). 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on shorebirds and coastal nesting birds are expected. 

C.5 Fisheries Resources 

C.5.1 Pelagic Communities and Ichthyoplankton 

Biggs and Ressler (2000) reviewed the biology of pelagic communities in the deepwater 

environment of the northern Gulf of Mexico. The biological oceanography of the region is 

dominated by the influence of the Loop Current, whose surface waters are among the most 

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oligotrophic in the world’s oceans. Superimposed on this low-productivity condition are 

productive “hot spots” associated with entrainment of nutrient-rich Mississippi River water and 

mesoscale oceanographic features. Anticyclonic and cyclonic hydrographic features play an 

important role in determining biogeographic patterns and controlling primary productivity in the 

northern Gulf of Mexico (Biggs and Ressler, 2000). 

Most fishes inhabiting shelf or oceanic waters of the Gulf of Mexico have planktonic eggs and 

larvae (Ditty, 1986; Ditty et al., 1988; Richards et al., 1989, 1993). Pelagic eggs and larvae 

become part of the planktonic community for various lengths of time (10 to 100 days, 

depending on the species) (MMS, 2007b). A study by Ross et al. (2012) on midwater fauna to 

characterize vertical distribution of mesopelagic fishes in selected deepwater areas in the 

Gulf of Mexico substantiated high species richness, but general domination by relatively few 

families and species. 

IPFs that could potentially affect pelagic communities and ichthyoplankton include drilling rig 

presence, noise, and lights; effluent discharges; water intakes; and two types of accidents – a 

small fuel spill and a large oil spill. 

Impacts of Drilling Rig Presence, Noise, and Lights 

The drilling rig, as a floating structure in the deepwater environment, will act as a fish-attracting 

device (FAD). In oceanic waters, the FAD effect would be most pronounced for epipelagic fishes 

such as tunas, dolphin, billfishes, and jacks, which are commonly attracted to fixed and drifting 

surface structures (Holland et al., 1990; Higashi, 1994; Relini et al., 1994). This FAD effect could 

possibly enhance the feeding of epipelagic predators by attracting and concentrating smaller 

fish species. Because the drilling rig is a single, temporary structure, impacts on fish 

populations, whether beneficial or adverse, are considered minor. 

Impacts of Effluent Discharges 

Discharges of treated SBM cuttings will produce temporary, localized increases in suspended 

solids in the water column around the drilling rig. In general, turbid water can be expected to 

extend between a few hundred meters and several kilometers down current from the discharge 

point (NRC, 1983; Neff, 1987). NPDES permit limits and requirements will be met. 

Treated sanitary and domestic wastes may have a slight effect on the pelagic environment in the 

immediate vicinity of these discharges. These wastes may have elevated levels of nutrients, 

organic matter, and chlorine, but will be diluted rapidly to undetectable levels within tens to 

hundreds of meters from the source. Minimal impacts on water quality, plankton, and nekton 

are anticipated. 

Deck drainage may have a slight effect on the pelagic environment in the immediate vicinity of 

these discharges. Deck drainage from contaminated areas will be passed through an oil and 

water separator prior to release, and discharges will be monitored for visible sheen. The 

discharges may have slightly elevated levels of hydrocarbons but will be diluted rapidly to 

undetectable levels within tens to hundreds of meters from the source. Minimal impacts on 

water quality, plankton, and nekton are anticipated. 

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Other discharges in accordance with the NPDES permit, such as desalination unit brine and 

uncontaminated cooling water, fire water, and ballast water, are expected to be diluted rapidly 

and have little or no impact on water column biota. 

Impacts of Water Intakes 

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

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

(EP Table 7a). Section 316(b) of the Clean Water Act requires NPDES permits to ensure that the 

location, design, construction, and capacity of cooling water intake structures reflect the best 

technology available to minimize adverse environmental impact from impingement and 

entrainment of aquatic organisms. The current general NPDES Permit No. GMG 290000 

specifies requirements for new facilities for which construction commenced after July 17, 2006 

with a cooling water intake structure having a design intake capacity of greater than two million 

gallons of water per day, of which at least 25% is used for cooling purposes. As discussed 

previously, since the drilling vessel selected for this project will meet the described 

requirements for new facilities, the vessel’s water intakes are expected to be in compliance with 

the design, monitoring, and recordkeeping requirements of the NPDES permit. 

Because of the limited scope and short duration of drilling activities and compliance with the 

NPDES permit to minimize adverse environmental impact from impingement and entrainment 

of aquatic organisms, any short-term impacts of entrainment are not expected to be biologically 

significant to plankton or ichthyoplankton populations. 

Impacts of a Small Fuel Spill 

Potential spill impacts on fisheries resources are discussed in MMS (2007b) and 

BOEM (2012a,b,d). For this EP, there are no unique site-specific issues with respect to 

spill impacts. 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations, including fuel transfer. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the potential for impacts on pelagic communities, 

including ichthyoplankton. EP Section 9b provides detail on spill response measures. Given the 

open ocean location of the lease area, the duration of a small spill and opportunity for impacts 

to occur would be very brief. 

A small fuel spill in offshore waters would produce a slick on the water surface and increase the 

concentrations of petroleum hydrocarbons and their degradation products. The extent and 

persistence of impacts would depend on the meteorological and oceanographic conditions at 

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that more than 90% would be evaporated or dispersed 

naturally within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 

12 ac (0.5 to 5 ha), depending on sea state and weather conditions. 

A small fuel spill could have localized impacts on phytoplankton, zooplankton, ichthyoplankton, 

and nekton. Due to the limited areal extent and short duration of water quality impacts, a small 

fuel spill would be unlikely to produce detectable impacts on pelagic communities. 

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Impacts of a Large Oil Spill 

Potential spill impacts on pelagic communities and ichthyoplankton are discussed in 

BOEM (2012a,b,d). For this EP, there are no unique site-specific issues. 

A large oil spill could affect water column biota including phytoplankton, zooplankton, 

ichthyoplankton, and nekton. A large spill that persisted for weeks or months would be more 

likely to affect these communities. While adult and juvenile fishes may actively avoid a large 

spill, planktonic eggs and larvae would be unable to avoid contact. Eggs and larvae of fishes in 

the upper layers of the water column are especially vulnerable to oiling; certain toxic fractions 

of spilled oil may be lethal to these life stages. Impacts would be potentially greater if local 

scale currents retained planktonic larval assemblages (and the floating oil slick) within the same 

water mass. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on pelagic communities and ichthyoplankton are expected. 

C.5.2 Essential Fish Habitat 

Essential Fish Habitat (EFH) is defined as those waters and substrate necessary to fish for 

spawning, breeding, feeding, and growth to maturity. Under the Magnuson-Stevens Fishery 

Conservation and Management Act, as amended, federal agencies are required to consult on 

activities that may adversely affect EFH designated in Fishery Management Plans developed by 

the regional Fishery Management Councils. 

The Gulf of Mexico Fishery Management Council (GMFMC) has prepared Fishery Management 

Plans for corals and coral reefs, shrimps, stone crab, spiny lobster, reef fishes, coastal migratory 

pelagic fishes, and red drum. In 2005, the EFH for these managed species was redefined in 

Generic Amendment No. 3 to the various Fishery Management Plans (GMFMC, 2005). The EFH 

for most of these GMFMC-managed species is on the continental shelf in waters shallower than 

600 ft (183 m). The shelf edge is the outer boundary for coastal migratory pelagic fishes, reef 

fishes, and shrimps. EFH for corals and coral reefs includes some shelf-edge topographic 

features on the Texas-Louisiana OCS, the nearest of which is located 42 miles (68km) 

north-northwest of the lease area. 

EFH has been identified in the deepwater Gulf of Mexico for highly migratory pelagic fishes, 

which occur as transients in the lease area. Species in this group, including tunas, swordfishes, 

billfishes, and sharks, are managed by NMFS. Highly migratory species with EFH at or near the 

lease area include the following (NMFS, 2009b):

 Atlantic bigeye tuna ( juveniles) 

 Atlantic bluefin tuna (spawning, 

eggs, larvae, adults) 

 Atlantic sailfish (adults 

 Atlantic skipjack tuna (spawning, 

adults) 

 Atlantic swordfish (larvae, juveniles, 

adults) 

 Atlantic yellowfin tuna (spawning, 

juveniles, adults) 

 Bigeye thresher shark (all) 

 Blue Marlin (juveniles and adults) 

 Longbill spearfish (adults, juveniles) 

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 Longfin mako shark (all) 

 Oceanic whitetip shark (all) 

 Sailfish (adults) 

 Shortfin mako shark (all) 

 Silky shark (all) 

 White marlin (juveniles, adults) 

Research indicates the central and western Gulf of Mexico may be important spawning habitat 

for Atlantic bluefin tuna, and NMFS (2009b) has designated a Habitat Area of Particular Concern 

(HAPC) for this species. The HAPC covers much of the deepwater Gulf of Mexico, including the 

lease area (Figure 1). The areal extent of the HAPC is approximately 115,830 mi2 (300,000 km2). 

The prevailing assumption is that Atlantic bluefin tuna follow an annual cycle of foraging in 

June through March off the eastern United States and Canadian coasts, followed by migration to 

the Gulf of Mexico to spawn in April, May, and June (NMFS, 2009b).

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 149 miles (240 km) west 

of the lease area. 

Routine IPFs that could potentially affect EFH and fisheries resources include drilling rig 

presence, noise, and lights; effluent discharges; and water intakes. In addition, two types of 

accidents – a small fuel spill and a large oil spill may potentially affect EFH and fisheries 

resources. 

Impacts of Drilling Rig Presence, Noise, and Lights 

The drilling rig, as a floating structure in the deepwater environment, will act as an FAD. 

In oceanic waters, the FAD effect would be most pronounced for epipelagic fishes such as tunas, 

dolphin, billfishes, and jacks, which are commonly attracted to fixed and drifting surface 

structures (Holland et al., 1990; Higashi, 1994; Relini et al., 1994). This FAD effect would 

possibly enhance feeding of epipelagic predators by attracting and concentrating smaller fish 

species. Any impacts on EFH for highly migratory pelagic fishes are considered minor. 

Impacts of Effluent Discharges 

Other effluent discharges affecting EFH by diminishing ambient water quality include drilling 

mud and cuttings, treated sanitary and domestic wastes, deck drainage, and miscellaneous 

discharges such as desalination unit brine and uncontaminated cooling water, fire water, and 

ballast water. Impacts on EFH from effluent discharges are anticipated to be similar to those 

described in Section C.5.1 for pelagic communities. No significant impacts on EFH for highly 

migratory pelagic fishes are expected from these discharges. 

Impacts of Water Intakes 

As noted previously, cooling water intake will cause entrainment and impingement of plankton, 

including fish eggs and larvae (ichthyoplankton). Due to the limited scope, timing, and 

geographic extent of drilling activities, any short-term impacts on EFH for highly migratory 

pelagic fishes are not expected to be biologically significant. 

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Impacts of a Small Fuel Spill 

Potential spill impacts on EFH are discussed in MMS (2007b) and BOEM (2012a,b,d). For this EP, 

there are no unique site-specific issues with respect to spill impacts. 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations, including fuel transfer. In the unlikely event of a spill, implementation of 

Shell’s OSRP will mitigate and reduce the potential for impacts on EFH. EP Section 9b provides 

detail on spill response measures. Given the open ocean location of the lease area, the duration 

of a small spill and opportunity for impacts to occur would be very brief. 

A small fuel spill in offshore waters would produce a slick on the water surface and increase the 

concentrations of petroleum hydrocarbons and their degradation products. The extent and 

persistence of impacts would depend on the meteorological and oceanographic conditions at 

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate 

of a small fuel spill and indicates that more than 90% would be evaporated or dispersed 

naturally within 24 hours. The area of diesel fuel on the sea surface would range from 1.2 to 

12 ac (0.5 to 5 ha), depending on sea state and weather conditions. 

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. Therefore, no significant spill impacts on EFH for highly 

migratory pelagic fishes are expected. 

A small fuel spill would not affect EFH for corals and coral reefs; the nearest coral EFH is located

42 miles (67 km) northwest of the lease area. A small fuel spill would float and dissipate on the 

sea surface and would not contact these features. Therefore, no significant spill impacts on EFH 

for corals and coral reefs are expected.

Impacts of a Large Oil Spill 

Potential spill impacts on EFH are discussed in MMS (2007b) and BOEM (2012a,b,d). For this EP, 

there are no unique site-specific issues with respect to EFH. 

An oil spill in offshore waters would temporarily increase hydrocarbon concentrations on the 

water surface and potentially the subsurface as well. Given the extent of EFH designations in 

the Gulf of Mexico (GMFMC, 2005; NMFS, 2009b), some impact on EFH would be unavoidable. 

A large spill could affect the EFH for many managed species including shrimps, stone crab, spiny 

lobster, corals and coral reefs, reef fishes, coastal migratory pelagic fishes, red drum, and highly 

migratory pelagic fishes. It would result in adverse impacts on water quality and water column 

biota including phytoplankton, zooplankton, ichthyoplankton, and nekton. In coastal waters, 

sediments could be contaminated and result in persistent degradation of the seafloor habitat 

for managed demersal fish and invertebrates. 

The lease area is within the HAPC for spawning Atlantic bluefin tuna (NMFS, 2009b). A large spill 

could temporarily degrade the HAPC due to increased hydrocarbon concentrations in the water 

column, with the potential for lethal or sublethal impacts on spawning tuna and their offspring. 

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Potential impacts would depend in part on the timing of a spill, as this species migrates to the 

Gulf of Mexico to spawn in April, May, and June (NMFS, 2009b).

The nearest feature designated as EFH for corals is located 42 miles (68 km) northwest of the 

lease area. An accidental spill would be unlikely to reach or affect this feature. Near-bottom 

currents in the region are expected to flow along the isobaths (Nowlin et al., 2001) and typically 

would not carry a plume up onto the continental shelf edge. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on EFH are expected. 

C.6 Archaeological Resources 

C.6.1 Shipwreck Sites 

MC 809 is on the list of archaeological survey blocks determined to have a high potential for 

containing archaeological properties. (BOEM, 2012c). A geologic, stratigraphic, and 

archaeological assessment detected marine avoidance targets within 2,000 ft (610 m) of each of 

the proposed wellsites, but none were identified as shipwrecks (C&C, 2009a; Fugro, 1991, 1992). 

Because there are no historic shipwreck sites in the lease area (see EP Section 6), there are no 

routine IPFs that are likely to affect these resources. A small fuel spill would not affect 

shipwrecks in adjoining blocks because the oil would float and dissipate on the sea surface. The 

impact of a large oil spill that could contact shipwrecks in other areas is considered below a level 

of concern. 

Impacts of a Large Oil Spill 

There are no known historic shipwrecks in the lease area, and a large oil spill would not result in 

any impact on archaeological resources. A spill entering shallow coastal waters could 

conceivably contaminate an undiscovered or known historic shipwreck site. The OSRA modeling 

summarized in Table 3 predicts that Texas, Louisiana, and Florida shorelines could be contacted 

by a spill within 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, 2008), depending on its extent, 

trajectory, and persistence. 

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BOEM (2012b) reexamined the analyses for archaeological resources presented in MMS (2007a, 

2008) based on additional information available since the publication of these two documents 

and in consideration of the Macondo oil spill. Substantial new information that alters the initial 

impact conclusion for archaeological resources has come to light as a result of BOEM-sponsored 

studies and industry surveys. Specifically, evidence of damage to significant cultural resources 

(i.e., historic shipwrecks) has been shown to have occurred because of an incomplete 

knowledge of seafloor conditions in lease areas >200 m (>656 ft) deep that have been exempted 

from high-resolution surveys. Since significant historic shipwrecks recently have been 

discovered outside the previously designated high-probability areas (some of which show 

evidence of impacts from permitted activities prior to their discovery), a survey is now required 

for exploration and development projects. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on historic shipwrecks are expected. Also as noted in MMS (2007b), 

should an oil spill contact a coastal historic site, such as a fort or a lighthouse, the major impact 

would be a temporary, reversible visual impact from oil contact and contamination of the site 

and its environment. However, more recent studies suggest that the impacts could be longer 

term and not easily reversible (BOEM, 2012b,d).

C.6.2 Prehistoric Archaeological Sites 

With water depths ranging from approximately 3,615 to 3,645 ft (1,102 to 1,111 m), the 

wellsites are well beyond the 60-m (197-ft) depth contour used by the BOEM as the seaward 

extent for prehistoric archaeological site potential in the Gulf of Mexico. A geologic, 

stratigraphic, and archaeological assessment detected marine avoidance targets within 2,000 ft 

(610 m) of all of the proposed wellsites (C&C, 2009a; Fugro, 1991, 1992), but none were 

suggestive of submerged cultural resources. Because prehistoric archaeological sites are not 

found in the lease area, the only relevant IPF is a large oil spill that would reach coastal waters 

within the 60-m (197-ft) depth contour. 

Impacts of a Large Oil Spill 

Because prehistoric archaeological sites are not found in the lease area, they would not be 

affected by the physical effects of a subsea blowout. MMS (2007b) estimates that a severe 

subsurface blowout could resuspend and disperse sediments within a 984-ft (300-m) radius. 

Along the northern Gulf Coast, prehistoric sites occur frequently along the barrier islands and 

mainland coast and along the margins of bays and bayous (MMS, 2007b). The OSRA modeling 

summarized in Table 3 predicts that Texas, Louisiana, and Florida shorelines could be contacted 

by a spill within 30 days. A spill reaching a prehistoric site along these shorelines could coat 

fragile artifacts or site features and compromise the potential for radiocarbon dating organic 

materials in a site (although other dating methods are available and it is possible to 

decontaminate an oiled sample for radiocarbon dating). Coastal prehistoric sites could also be 

damaged by spill cleanup operations (e.g., by destroying fragile artifacts and disturbing the 

provenance of artifacts and site features). BOEM (2012b) notes that some unavoidable direct 

and indirect impacts on coastal historic resources could occur, resulting in the loss of 

information. 

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A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an 

event will be minimized by Shell’s well control and blowout prevention measures as detailed in 

EP Section 2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and 

reduce the impacts. EP Section 9b provides detail on spill response measures. Therefore, no 

significant spill impacts on archaeological resources are expected. 

C.7 Coastal Habitats and Protected Areas 

Coastal habitats in the northern Gulf of Mexico that may be affected by oil and gas activities are 

described in previous EISs (MMS, 2007b; BOEM, 2012a,b,d) and in a literature review by Collard 

and Way (1997). Sensitive coastal habitats are also tabulated in the OSRP. Coastal habitats 

inshore of the project area include barrier beaches and dunes, wetlands, and submerged 

seagrass beds. Generally, most of the northern Gulf is fringed by barrier beaches, with wetlands 

and/or submerged seagrass beds occurring in sheltered areas behind the barrier islands and in 

estuaries. 

Due to the distance from shore, there are no IPFs associated with routine activities occurring in 

the lease area that are likely to affect beaches and dunes, wetlands, seagrass beds, coastal 

wildlife refuges, wilderness areas, or any other managed or protected coastal area. The support 

bases at Port Fourchon and Boothville, Louisiana, are not located in a wildlife refuge or a 

wilderness area. Potential impacts of support vessel traffic are briefly addressed in this section. 

A small fuel spill in the lease area would be unlikely to affect coastal habitats, because it would 

not be expected to make landfall or reach coastal waters prior to breaking up (see explanation 

in Section A.9.2).

Impacts of Support Vessel Traffic 

For OCS activities in general, support operations, including the crew boat and supply boats, may 

have a minor incremental impact on coastal habitats. Over time with a large number of vessel 

trips, vessel wakes can erode shorelines along inlets, channels, and harbors. Support 

operations, including the crew boat and supply boats as detailed in EP Section 14, may have a 

minor incremental impact on coastal habitats or protected areas. Impacts will be minimized by 

following the speed and wake restrictions in harbors and channels. 

Impacts of a Large Oil Spill 

Potential spill impacts on coastal habitats are discussed in MMS (2007b) and BOEM (2012a,b,d). 

Coastal habitats inshore of the project area include barrier beaches and dunes, wetlands, and 

submerged seagrass beds. For this EP, there are no unique site-specific issues with respect to 

coastal habitats. 

The OSRA results summarized in Table 3 predict that shorelines of Texas, Louisiana, and Florida 

could be affected within 30 days. Nearshore waters and embayments of Plaquemines Parish, 

Cameron Parish, Terrebonne Parish, and Lafourche Parish, Louisiana, have the highest 

probability on contact within 30 days. After 30 days, 11 counties or parishes may be contacted 

from Texas to Florida. 

The shorelines within the geographic range predicted by the OSRA modeling include extensive 

barrier beaches and wetlands, with submerged seagrass beds occurring in sheltered areas 

behind the barrier islands and in estuaries. NWRs and other protected areas along the coast are 

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discussed in the lease sale EISs (MMS, 2007b; BOEM, 2012b) and Shell’s OSRP. Coastal wildlife 

refuges, wilderness areas, and state and national parks within the geographic range of the 

potential shoreline contacts after 30 days include the following: 

 Anahuac NWR 

 Apalachicola Bay Aquatic Preserve 

Outstanding Florida Water 

 Apalachicola National Estuarine 

Research Reserve 

 Apalachicola River and Bay SWIM Area 

 Apalachicola River Wildlife and 

Environmental Area 

 Apffel Park 

 Aransas NWR 

 Atchafalaya Delta WMA 

 Atkinson Island WMA 

 Bayou Portage Coastal Preserve 

 Bayou Sauvage NWR 

 Bayou Teche NWR 

 Bellefontaine Point Coastal Reserve 

 Big Boggy NWR 

 Big Branch Marsh NWR 

 Big Lagoon State Recreation Area 

 Biloxi Marshes State Coastal Preserve 

 Biloxi River Coastal Reserve 

 Biloxi WMA 

 Bon Secour NWR 

 Brazoria NWR 

 Breton NWR 

 Buccaneer State Park 

 Cameron Prairie NWR 

 Candy Abshier WMA 

 Choctawatchee Bay SWIM Area 

 Christmas Bay Coastal Preserve 

 Christmas Bay State Park 

 Cypremort Point State Park 

 Davis Bayou Coastal Preserve 

 Deer Island State Coastal Preserve 

 Deer Lake State Park 

 Delta NWR 

 Fort Pickens State Park Aquatic 

Preserve 

 Ft. Anahuac Park 

 Galveston Island State Park 

 Goose Island State Park 

 Grand Bay National Estuarine 

Research Reserve 

 Grand Bay NWR 

 Grand Bay Savannah Coastal Preserve 

 Grand Bayou Coastal Preserve 

 Grand Isle State Park 

 Graveline Bay Coastal Reserve 

 Grayton Beach State Park Outstanding 

Florida Water 

 Guadalupe Delta WMA 

 Gulf Islands National Seashore 

 Gulf State Park 

 Hancock County Marsh Coastal 

Reserve 

 Henderson State Park 

 Isles Dernieres Barrier Islands Refuge 

 Jean Lafitte National Historical Park 

and Preserve 

 Jourdan River Coastal Reserve 

 LaCassine NWR 

 Lafitte Woods NA 

 Laguna Madre Estuarine And Coastal 

Marine Area 

 Lake Corpus Christi State Park 

 Lillian Swamp Mitigation Area 

 Little Pecan Island NA 

 Lower Neches WMA 

 Mad Island WMA 

 Mandalay NWR 

 Marsh Island WMA 

 Matagorda Island State Park 

 McFaddin NWR 

 Meaher State Park 

 Mission-Aransas National Estuarine 

Research Reserve 

 Mississippi Sandhill Crane NWR 

 Murphree WMA 

 Mustang Island State Park 

 Old Fort Bayou Coastal Reserve 

 Old Fort Travis Park 

 Padre Island National Seashore 

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 Pascagoula River Coastal Reserve 

 Pass Au Loutre WMA 

 Paul J. Rainey WMA 

 Peach Point WMA 

 Pearl River WMA 

 Penalver State Park 

 Pensacola Bay SWIM Area 

 Perdido Key State Recreation Area 

 Peveto Woods NA 

 Point Au Chein WMA 

 Point Washington Outstanding Florida 

Water 

 Port Aransas Park 

 Rockefeller WMA 

 Sabine NWR 

 Salvador WMA 

 San Bernard NWR 

 Sea Rim State Park 

 Seawolf Park 

 Shell Keys NWR 

 St. Andrew Bay Watershed SWIM Area 

 St. Andrews State Park 

 St. Andrews State Park Aquatic 

Preserve 

 St. Bernard State Park 

 St. George Island State Park 

 St. Joseph Bay State Buffer Preserve 

 St. Joseph Peninsula State Park 

 St. Vincent NWR 

 Tarkiln Bayou State Preserve 

 Texas Point NWR 

 The Grand Bay Savanna Tract 

 W.L. Holland WMA 

 Weeks Bay National Estuarine 

Research Reserve 

 Welder Flats Coastal Preserve 

 Winser WMA 

 Wolf River Coastal Reserve 

 Yellow River WMA 

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The OSRA results in Table 3 include only shoreline segments with contact probabilities greater than 

0.5% within 30 days; other coastal areas could be affected at lower contact probabilities within 

30 days, or from a spill persisting for more than 30 days. Additional NWRs and managed wildlife 

areas occur along the Gulf Coast. These areas include habitats such as barrier beach and dune 

systems, wetlands, and submerged seagrass beds that support diverse wildlife, including endangered 

or threatened species. 

The level of impacts from oil spills on coastal habitats depends on many factors, including the oil 

characteristics, the geographic location of the landfall, and the weather and oceanographic 

conditions at the time (MMS, 2007b). Oil that makes it to beaches may be either liquid weathered 

oil, an oil-and-water mousse, or tarballs (MMS, 2007b). Oil is generally deposited on beaches in lines 

defined by wave action at the time of landfall. Oil that remains on the beach will thicken as its 

volatile components are lost. Thickened oil may form tarballs or aggregations that incorporate sand, 

shell, and other materials into its mass. Tar may be buried to varying depths under the sand. On 

warm days, both exposed and buried tarballs may liquefy and ooze. Oozing may also serve to expand 

the size of a mass as it incorporates beach materials. Oil on beaches may be cleaned up manually, 

mechanically, or both. Some oil can remain on the beach at varying depths and may persist for 

several years as it slowly biodegrades and volatilizes. 

Coastal wetlands are highly sensitive to oiling and can be significantly impacted because of the 

inherent toxicity of hydrocarbon and non-hydrocarbon components of the spilled substances 

(Mendelssohn, 2012). The MMS (2007b) predicted that for every 50 bbl of oil contacting wetlands, 

approximately 6.7 ac (2.7 ha) of wetland vegetation will experience dieback. Thirty percent of these 

damaged wetlands are assumed to recover within 4 years, and 85% within 10 years. About 15% of 

the contacted wetlands are expected to be converted permanently to open-water habitat. The 

critical concentration of oil is that concentration above which impacts to wetlands will be long term 

and recovery will take longer than two growing seasons, and which causes plant mortality and some 

permanent wetland loss. Critical concentrations of various oils are expected to vary broadly for 

wetland types and wetland plant species. Louisiana wetlands are assumed to be more sensitive to oil 

contact than elsewhere in the Gulf because of high cumulative stress (MMS, 2007b). In addition to 

the direct impacts of oil, cleanup activities in marshes may accelerate rates of erosion and retard 

recovery rates (MMS, 2007b). 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an event 

will be minimized by Shell’s well control and blowout prevention measures as detailed in EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on coastal habitats are expected. 

C.8 Socioeconomic and Other Resources 

C.8.1 Recreational and Commercial Fishing 

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. 

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It is unlikely that any commercial fishing activity other than longlining occurs at or near the project 

area. Benthic species targeted by commercial fishers occur on the upper continental slope, well 

inshore of the project area. Royal red shrimp (Pleoticus robustus) are caught by trawlers in water 

depths of about 820 to 1,804 ft (250 to 550 m). Tilefishes (primarily Lophalotilus chamaeleonticeps) 

are caught by bottom longlining in water depths from about 540 to 1,476 ft (165 to 450 m) 

(Continental Shelf Associates, Inc., 2002). The proposed project is in 3,615 to 3,645 ft 

(1,102 to 1,111 m) of water. No conflict with commercial fishing activity other than longlining 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 proposed 

project is 55 miles (89 km) from the nearest shoreline. Due to the distance from shore, it is unlikely 

that any recreational fishing activity is occurring in the project area. 

The only routine IPF that could potentially affect fisheries is drilling rig presence (including noise and 

lights). Two types of potential accidents are also addressed in this section – a small fuel spill and a 

large oil spill. 

Impacts of Drilling Rig Presence 

There is a slight possibility of pelagic longlines becoming entangled in the drilling rig. For example, in 

January 1999, a portion of a pelagic longline snagged on the acoustic Doppler current profiler of a 

drillship working in the Gulf of Mexico (Continental Shelf Associates, Inc., 2002). The line was 

removed without incident. Generally, longline fishers use radar and are aware of offshore structures 

and ships when placing their sets. Therefore, little or no impact on pelagic longlining is expected. 

No adverse impacts on fishing activities are anticipated. Other factors such as effluent discharges are 

likely to have negligible impacts on commercial or recreational fisheries due to rapid dispersion, the 

small area of ocean affected, and the intermittent nature of the discharges. 

Impacts of a Small Fuel Spill 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations, including fuel transfer. In the unlikely event of a spill, implementation of Shell’s OSRP will 

mitigate and reduce the potential for impacts. EP Section 9b provides detail on spill response 

measures. Given the open ocean location of the lease area, the duration of a small spill and 

opportunity for impacts to occur would be very brief. 

Pelagic longlining activities in the lease area, if any, could be interrupted in the event of a small fuel 

spill. The area of diesel fuel on the sea surface would range from 1.2 to 12 ac (0.5 to 5 ha), 

depending on sea state and weather conditions. Fishing activities could be interrupted due to the 

activities of response vessels operating in the lease area. A small fuel spill would not affect coastal 

water quality because the spill would not be expected to make landfall or reach coastal waters prior 

to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill 

Potential spill impacts on fishing activities are discussed in MMS (2007b) and BOEM (2012b,d). For 

this EP, there are no unique site-specific issues with respect to this activity. 

Pelagic longlining activities in the lease area and other fishing activities in the northern Gulf of Mexico 

could be interrupted in the event of a large oil spill. A spill may or may not result in fishery closures, 

depending on the duration of the spill, the oceanographic and meteorological conditions at the time, 

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and the effectiveness of spill response measures. A blowout resulting in a large oil spill is an 

extremely rare event, and the probability of such an event will be minimized by Shell’s well control 

and blowout prevention measures as detailed in EP Section 2j. In the unlikely event of a spill, 

implementation of Shell’s OSRP will mitigate and reduce the impacts. EP Section 9b provides detail 

on spill response measures. Therefore, no significant spill impacts on fishing activities are expected. 

C.8.2 Public Health and Safety 

There are no IPFs associated with routine operations that are expected to affect public health and 

safety. Impacts of a small fuel spill and a large oil spill are addressed in this section. 

Impacts of a Small Fuel Spill 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations, including fuel transfer. In the unlikely event of a spill, implementation of Shell’s OSRP will 

mitigate and reduce the potential for impacts. EP Section 9b provides detail on spill response 

measures. 

A small fuel spill would not have impacts on public health and safety because it would likely affect 

only a small area of the open ocean 55 miles (89 km) from the nearest shoreline and nearly all of the 

diesel fuel would evaporate or disperse naturally within 24 hours. Response crews would be 

equipped with appropriate safety equipment to avoid injury and health effects. A small fuel spill 

would not be expected to make landfall or reach coastal waters prior to breaking up (see 

Section A.9.2).

Impacts of a Large Oil Spill 

In the event of a large spill from a blowout, the main safety and health concerns are those of the 

offshore personnel involved in the incident and those responding to the spill. The proposed activities 

will be covered by the OSRP, and, in addition, the drilling rig maintains a Shipboard Oil Pollution 

Emergency Plan as required under MARPOL 73/78. 

Depending on the spill rate and duration, the physical/chemical characteristics of the oil, the 

meteorological and oceanographic conditions at the time, and the effectiveness of spill response 

measures, the public could be exposed to oil on the water and along the shoreline, through skin 

contact or inhalation of VOCs. Crude oil is a highly flammable material, and any smoke or vapors 

from a crude oil fire can cause irritation. Exposure to large quantities of crude oil may pose a health 

hazard. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an event 

will be minimized by Shell’s well control and blowout prevention measures as detailed in EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on public health and safety are expected. 

C.8.3 Employment and Infrastructure 

There are no IPFs associated with routine operations that are expected to affect employment and 

infrastructure. The project involves drilling with support from existing shore-based facilities in 

Louisiana. No new or expanded facilities will be constructed, and no new employees are expected to 

move permanently into the area. The project will have a negligible impact on socioeconomic 

conditions such as local employment, existing offshore and coastal infrastructure (including major 

sources of supplies, services, energy, and water), and minority and lower income groups. Impacts of 

a small fuel spill and a large oil spill are addressed in this section. 

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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. EP Section and 9b provides detail on spill response 

measures. Given the open ocean location of the lease area and the duration of a small spill, the 

opportunity for impacts to occur would be very brief. 

A small fuel spill that is dissipated within a few days would have little or no economic impact, as the 

spill response would use existing facilities, resources, and personnel. 

Impacts of a Large Oil Spill 

Potential socioeconomic impacts of an oil spill are discussed MMS (2007b) and BOEM (2012b,d). For 

this EP, there are no unique site-specific issues with respect to employment and coastal 

infrastructure. A large spill could cause several types of economic impacts: extensive fishery closures 

could put fishermen out of work; temporary employment could increase as part of the response 

effort; adverse publicity could reduce employment in coastal recreation and tourism industries; and 

OCS drilling activities, including service and support operations that are an important part of local 

economies, could be suspended. 

The lease area is 55 miles (89 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 EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on employment and infrastructure are expected. 

C.8.4 Recreation and Tourism 

BOEM has reexamined the analyses for recreation and tourism presented in MMS (2007b, 2008) 

based on additional information and in consideration of the Macondo oil spill event. No new 

information was found that would alter the potential impacts on recreation and tourism (BOEMRE, 

2011; BOEM, 2012c).

There are no known recreational uses of the lease area. Recreational resources and tourism in 

coastal areas would not be affected by routine activities due to the distance from shore. Compliance 

with NTL 2012-BSEE-G01 will minimize the chance of trash or debris being lost overboard from the 

drilling rig and subsequently washing up on beaches. 

Impacts of a Small Fuel Spill 

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine 

operations, including fuel transfer. In the unlikely event of a spill, implementation of Shell’s OSRP will 

mitigate and reduce the potential for impacts. EP Section 9b provides detail on spill response 

measures. Given the open ocean location of the lease area, the duration of a small spill and 

opportunity for impacts to occur would be very brief. 

A small fuel spill in the lease area would be unlikely to affect recreation and tourism. There are no 

known recreational or tourism activities occurring in the lease area, and as explained in 

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Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters prior 

to breaking up. 

Impacts of a Large Oil Spill 

Potential impacts of an oil spill on recreation and tourism are discussed in MMS (2007b) and BOEM 

(2012a,b,d). For this EP, there are no unique site-specific issues with respect to these impacts. 

Impacts on recreation and tourism would vary depending on the duration of the spill and its fate 

including the effectiveness of response measures. A large spill that reached coastal waters and 

shorelines could adversely affect recreation and tourism by contaminating beaches and wetlands, 

resulting in negative publicity that encourages people to stay away. The OSRA results summarized in 

Table 3 predict that shorelines of Texas, Louisiana, and Florida could be affected within 30 days. 

Nearshore waters and embayments of Plaquemines Parish, Cameron Parish, Terrebonne Parish, and 

Lafourche Parish, Louisiana, have the highest probability of contact within 30 days. The shorelines 

along Galveston, Texas, which include popular beaches and recreational sites, could be affected. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an event 

will be minimized by Shell’s well control and blowout prevention measures as detailed in EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on recreation and tourism are expected. 

C.8.5 Land Use 

Land use along the northern Gulf Coast is discussed in MMS (2007b) and BOEM (2012b,d). There are 

no routine IPFs potentially affecting land use. The project will use existing onshore support facilities 

in Louisiana. The land use at the existing shorebase sites is industrial. The project will not involve 

new construction or changes to existing land use and, therefore, will not have any impacts. Levels of 

boat and helicopter traffic, as well as demand for goods and services, including scarce coastal 

resources, will represent a small fraction of the level of activity occurring at the shorebases. 

A large oil spill is the only relevant accident IPF. A small fuel spill would not have impacts on land 

use, as the response would be staged out of existing shorebases and facilities. 

Impacts of a Large Oil Spill 

The initial response for a large oil spill would be staged out of existing facilities, with no effect on land 

use. A large spill could have limited temporary impacts on land use along the coast if additional 

staging areas were needed. For example, during the Macondo spill, 25 temporary staging areas were 

established in Louisiana, Mississippi, Alabama, and Florida for spill response and cleanup efforts 

(BOEM, 2012b). In the event of a large spill in the lease area, similar temporary staging areas could 

be needed. These areas would eventually return to their original use as the response is demobilized. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an event 

will be minimized by Shell’s well control and blowout prevention measures as detailed in EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on land use are expected. 

C.8.6 Other Marine Uses 

The lease area is not located within any USCG-designated fairway or shipping lane and MC 809 is not 

in a designated Military Warning Area. Shell will comply with BOEM requirements and lease 

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stipulations to avoid impacts on uses of the area by military vessels and aircraft. The proposed 

wellsites range from 600 to 1,050 ft (183 to 320 m) from Shell’s MC 756 to 809 Ursa TLP flowline and 

umbilicals (C&C, 2009a; Fugro, 1991, 1992). 

The geologic, stratigraphic, and archaeological assessment detected marine avoidance targets within 

2,000 ft (610 m) of all of the proposed wellsites. Additional marine avoidance targets are present in 

the 2,000 to 3,000 ft (610 to 914 m) buffer zone around all wells (C&C, 2009a; Fugro, 1991, 1992). 

Waste barrels were identified within the vicinity of all of the proposed wellsites (C&C, 2009a; Fugro, 

1991, 1992). 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 overarching policy is to avoid barrel contact. In 

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

specifies actions to be taken for the topside safety of personnel handling the equipment. The plan 

also outlines barrel impact reporting procedures. 

There are no IPFs from routine project activities that are likely to affect shipping or other marine 

uses. A large oil spill is the only relevant accident IPF. A small fuel spill would not have impacts on 

other marine uses, as the spill and response activities would be mainly within the lease area, and the 

duration would be brief. 

Impacts of a Large Oil Spill 

An accidental spill would be unlikely to significantly affect shipping or other marine uses. The block is 

not located within any USCG-designated fairway or shipping lane. In the event of a large spill 

requiring numerous response vessels, coordination would be required to manage the vessel traffic 

for safe operations. Shell will comply with BOEM requirements and lease stipulations to avoid 

impacts on uses of the area by military vessels and aircraft. 

A blowout resulting in a large oil spill is an extremely rare event, and the probability of such an event 

will be minimized by Shell’s well control and blowout prevention measures as detailed in EP Section 

2j. In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the 

impacts. EP Section 9b provides detail on spill response measures. Therefore, no significant spill 

impacts on other marine uses are expected. 

C.9 Cumulative Impacts 

For purposes of NEPA, cumulative impact is defined as “the impact on the environment which results 

from the incremental impact of the action when added to other past, present, and reasonably 

foreseeable future actions regardless of what agency (federal or non-federal) or person undertakes 

such other actions” (40 CFR 1508.7). Any single activity or action may have a negligible impact(s) by 

itself, but when combined with impacts from other activities in the same area and/or time period, 

substantial impacts may result. 

Prior Studies. Prior to the lease sales, MMS prepared a multisale EIS in which it analyzed the 

environmental impact of activities that might occur in the multi-lease-sale area. The MMS also 

recently analyzed the cumulative impacts of OCS development activities similar to those planned in 

this EP in several documents. The level and types of activities planned in Shell's EP are within the 

range of activities described and evaluated in the Final EIS for Gulf of Mexico OCS Oil and Gas Lease 

Sales 2007-2012: Western Planning Area Sales 204, 207, 210, 215, and 218, and Central Planning Area 

Sales 205, 206, 208, 213, 216, and 222 (MMS, 2007b), as updated by a 2012 Final Supplemental EIS 

for Gulf of Mexico OCS Oil and Gas Lease Sales 2012-2017: Western Planning Area Lease Sales 229, 

233, 246, and 248 and Central Planning Area Lease Sales 227, 231, 235, 241 and 247 (BOEM, 2012b). 

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Past, present, and reasonably foreseeable activities were identified in the cumulative effects scenario 

of these documents, which are incorporated by reference. The proposed action will not result in any 

additional impacts beyond those evaluated in the Multisale and Final EISs (MMS, 2007b; BOEM, 

2012b). 

Description of Activities Reasonably Expected to Occur in the Vicinity of Project Area. Other 

exploration and development activities may occur in the vicinity of lease block MC 809. Shell does 

not anticipate other projects in the vicinity of the project area beyond the types of projects analyzed 

in the Multisale and Supplemental EISs (MMS, 2007b, 2008; BOEMRE, 2011; BOEM, 2012b). 

Cumulative Impacts of Activities in the EP. The MMS (2007b) multi-lease-sale EIS and BOEM (2012b) 

Final EIS included a lengthy discussion of cumulative impacts, which analyzed the environmental and 

socioeconomic impacts from the incremental impact of the 11 proposed lease sales, in addition to all 

activities (including non-OCS activities) projected to occur from past, proposed, and future lease sales 

during the 40-year period of 2007 to 2046 (see MMS, 2007b; BOEM, 2012b). The EISs considered 

exploration, delineation, and development wells; platform installation; service-vessel trips; and oil 

spills. The EISs examined the potential cumulative effects on each specific resource for the entire 

Gulf of Mexico. 

The level and type of activity proposed in Shell’s EP are within the range of activities described and 

evaluated in the recent multi-lease-sale EISs. This EIA incorporates and builds on these analyses by 

examining the potential impacts on physical, biological, and socioeconomic resources from the work 

planned in this EP, in conjunction with the other reasonably foreseeable activities expected to occur 

in the Gulf of Mexico. Thus, for all impacts, the incremental contribution of Shell’s proposed actions 

to the cumulative impacts analysis in these prior analyses is not significant. 

C.9.1 Cumulative Impacts to Physical/Chemical Resources 

The work planned in this EP is limited in geographic scope and duration, and the impacts on the 

physical/chemical environment will be correspondingly limited. 

Air Quality. Emissions from pollutants into the atmosphere from activities are not projected to have 

significant effects on onshore air quality because of the prevailing atmospheric conditions, emission 

rates and heights, and resulting pollutant concentrations. As the BOEM found in the multi-lease-sale 

EISs, the incremental contribution of activities similar to Shell’s proposed activities to the cumulative 

impacts is not significant and will not cause or contribute to a violation of NAAQS (MMS, 2007b; 

BOEM, 2012b,d). In addition, the cumulative contribution to visibility impairment is also very small 

(MMS, 2007b; BOEM, 2012b,d). As mentioned in previous sections, projected emissions meet the 

BOEM exemption criteria and would not contribute to cumulative impacts on air quality. 

Climate Change. CO2 and CH4 emissions from the project would constitute a negligible contribution 

to greenhouse gas emissions from all OCS activities. According to a recent OCS lease sale EIS (BOEM, 

2012b), estimated CO2 emissions from OCS oil and gas sources are 0.4% of the U.S. total and all OCS 

activities are about 0.005% of the total global CO2 emissions. Greenhouse gas emissions may 

contribute to climate change, with important effects on temperature, rainfall, frequency of severe 

weather, ocean acidification, and sea level rise (Intergovernmental Panel on Climate Change, 2007). 

In the Gulf of Mexico, sea level rise is an important issue due to the ongoing losses in coastal 

wetlands, particularly in coastal Louisiana. Greenhouse gas emissions from the EP represent a 

negligible contribution to the total greenhouse gas emissions from reasonably foreseeable activities 

in the Gulf of Mexico area and would not significantly alter any of the climate change impacts 

evaluated in the previous EISs. Globally, Shell is working to reduce greenhouse gas emissions by 

increasing the efficiency of its operations, establishing a substantial capability in CO2 capture and 

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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). 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 809 is on the list of archaeology survey blocks (BOEM, 2012c). 

A geologic, stratigraphic, and archaeological assessment by C&C (2009a) and Fugro (1991, 1992) 

identified numerous unidentified sonar contacts, but none were suggestive of significant submerged 

cultural or archeological resources. Also, the lease area is well beyond the 60-m (197-ft) depth 

contour used by the BOEM as the seaward extent for prehistoric archaeological site potential in the 

Gulf of Mexico. Therefore, Shell’s operations will have no cumulative impacts on historic shipwrecks 

or prehistoric archaeological resources. 

New Information. New information included in the most recent Programmatic, Supplemental, and 

Final EISs (BOEM, 2012a,b,d) has been incorporated into the EIA, where applicable. 

C.9.2 Cumulative Impacts to Biological Resources 

The work planned in this EP is limited in geographic scope and duration, and the impacts on biological 

resources will be correspondingly limited. 

Seafloor Habitats and Biota. Effects on seafloor habitats and biota from discharges of drilling mud 

and cuttings are expected to be minor and limited to a small area. Areas that may support 

high-density deepwater benthic communities will be avoided as required by NTL 2009-G40. Soft 

bottom communities are ubiquitous along the northern Gulf of Mexico continental slope, and the 

extent of benthic impacts during this project is insignificant regionally. As noted in the multi-leasesale EISs, the incremental contributions of activities similar to Shell’s proposed activities to the 

cumulative impacts is not significant (MMS, 2007b; BOEM, 2012b,d).

Threatened, Endangered, and Protected Species. Threatened and endangered species reasonably 

likely to occur in the lease area include the sperm whale and five species of sea turtles. Potential 

impact sources include drilling rig presence including noise and lights, marine debris, and support 

vessel and aircraft traffic. Potential effects for these species would be limited and temporary, and 

would be reduced by Shell’s compliance with BOEM-required mitigation measures, including 

NTLs 2012-BSEE-G01 and 2012-JOINT-G01. No significant cumulative impacts are expected. 

Coastal and Marine Birds. Birds may be exposed to contaminants, including air pollutants and 

routine discharges, but significant impacts are unlikely due to rapid dispersion. Shell’s compliance 

with NTL 2012-BSEE-G01 will minimize the likelihood of debris-related impacts on birds. Support 

vessel and helicopter traffic may disturb some foraging and resting birds; however, it is likely that 

individual birds would experience, at most, only short-term behavioral disruption. 

Due to the limited scope, timing, and geographic extent of drilling activities, collisions or other 

adverse effects are unlikely, and no significant cumulative impacts are expected. 

Fisheries Resources. Exploration and production structures occur in the vicinity of the lease area. 

The additional effect of the proposed drilling activity would be negligible. 

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Coastal Habitats. Due to the distance of the wellsites from shore, routine activities are not expected 

to have any impacts on beaches and dunes, wetlands, seagrass beds, coastal wildlife refuges, 

wilderness areas, or any other managed or protected coastal area. The support bases at 

Port Fourchon and Boothville, Louisiana, are not in wildlife refuge or wilderness areas. Support 

operations, including the crew boat and supply boats, may have a minor incremental impact on 

coastal habitats. Over time with a large number of vessel trips, vessel wakes can erode shorelines 

along inlets, channels, and harbors. Impacts will be minimized by following the speed and wake 

restrictions in harbors and channels. 

New Information. New information included in the most recent Programmatic, Supplemental, and 

Final EISs (BOEM, 2012a,b,d) has been incorporated into the EIA, where applicable. 

C.9.3 Cumulative Impacts to Socioeconomic Resources 

The work planned in this EP is limited in geographic scope and duration, and the impacts on 

socioeconomic resources will be correspondingly limited. 

The multi-lease-sale and supplemental and final EISs analyzed the cumulative impacts of oil and gas 

exploration and development in the lease area, in combination with other impact-producing 

activities, on commercial fishing, recreational fishing, recreational resources, historical and 

archaeological resources, land use and coastal infrastructure, demographics, and environmental 

justice (MMS, 2007b; BOEM, 2012b,d). The BOEM also analyzed the economic impact of oil and gas 

activities on the Gulf states, finding only minor impacts in most of Texas, Mississippi, Alabama, and 

Florida, more significant impacts in parts of Texas, and substantial impacts on Louisiana. 

Shell’s proposed activities will have negligible cumulative impacts on socioeconomic resources. 

There are no IPFs associated with routine operations that are expected to affect public health and 

safety, employment and infrastructure, recreation and tourism, land use, or other marine uses. Due 

to the distance from shore, it is unlikely that any recreational fishing activity is occurring in the 

project area, and it is unlikely that any commercial fishing activity other than longlining occurs at or 

near the project area. The project will have negligible impacts on fishing activities. 

New Information. New information included in the most recent Programmatic, Supplemental, and 

Final EISs (BOEM, 2012a,b,d) has been incorporated into the EIA, where applicable. 

D. Environmental Hazards 

D.1 Geologic Hazards 

The shallow hazards assessment included in this EP concludes that the wellsites are suitable for the 

planned activities. Proposed wellsites HH, II, JJ, KK, LL, and MM are located 303, 687, 310, 300, 510, 

and 440 ft, respectively, from the nearest minor seafloor faults (C&C, 2009a; Fugro, 1991, 1992). No 

fault penetration is expected at any of the proposed wellsites. 

Based on results of a high-resolution geophysical survey consisting of frequency-enhanced threedimensional seismic, enhanced surface renderings, autonomous underwater vehicle surveys, and 

side-scan sonar, these locations appear suitable for the planned activity (C&C, 2009a; Fugro, 1991, 

1992). 

See EP Section 6a for supporting geological and geophysical information. 

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D.2 Severe Weather 

Under most circumstances, weather is not expected to have any effect on the proposed activities. 

Extreme weather, including high winds, strong currents, and large waves, was considered in the 

design criteria for the drilling rig. High winds and limited visibility during a severe storm could disrupt 

communication and support activities (vessel and helicopter traffic) and make it necessary to 

suspend some activities on the drilling rig for safety reasons until the storm or weather event passes. 

In the event of a hurricane, procedures in Shell’s Hurricane Evacuation Plan would be followed.

D.3 Currents and Waves 

A rig-based acoustic Doppler current profiler will be used to continuously monitor the current 

beneath the rig. Metocean conditions such as sea states, wind speed, ocean currents, etc., will also 

be continuously monitored. Under most circumstances, physical oceanographic conditions are not 

expected to have any effect on the proposed activities. Strong currents (caused by Loop Current 

eddies and intrusions) and large waves were considered in the design criteria for the drilling rig. High 

waves during a severe storm could disrupt support activities (i.e., vessel and helicopter traffic) and 

make it necessary to suspend some activities on the drilling rig for safety reasons until the storm or 

weather event passes. 

E. Alternatives 

No formal alternatives were evaluated in this EIA. However, various technical and operational 

options, including the location of the wellsites and the selection of a drilling unit, were considered by 

Shell in developing the proposed action. There are no other reasonable alternatives to accomplish 

the goals of this project. 

F. Mitigation Measures 

The proposed action includes numerous mitigation measures required by laws, regulations, and 

BOEM lease stipulations and NTLs. The project will comply with applicable federal, state, and local 

requirements concerning air pollutant emissions, discharges to water, and solid waste disposal. 

Project activities will be conducted under Shell’s OSRP and will include the measures described in 

EP Section 2f. 

G. Consultation 

No persons or agencies were consulted regarding potential impacts associated with the proposed 

activities during the preparation of this EIA. 

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H. Preparers 

This EIA was prepared at the direction of Shell Offshore Inc. by its contractor, CSA Ocean Sciences Inc. 

Contributors included the following: 

 Tracy Albert (Regulatory Specialist, Regulatory Compliance Consultants of LA, LLC); 

 Jeffrey McMenis (Environmental Engineer, Shell Exploration & Production Co.); 

 Phillip Horton (Staff Geologist, Shell Exploration & Production Co.); 

 Kim Mun Wong (Senior Well Engineer, Shell Exploration & Production Co.) 

 June Mire, Ph.D. (Senior Ecologist and Project Manager, Tetra Tech, Inc.); 

 John Thompson (Senior Scientist, CSA Ocean Sciences Inc.); 

 Neal Phillips, Ph.D. (Senior Scientist, CSA Ocean Sciences Inc.); 

 Deborah Fawcett (Project Scientist III, CSA Ocean Sciences Inc.); 

 John M. Tiggelaar II (Project Scientist I, CSA Ocean Sciences Inc.); 

 Stephen Viada (Senior Scientist, CSA Ocean Sciences Inc.); 

 Keith VanGraafeiland (GIS/Remote Sensing Specialist, CSA Ocean Sciences Inc.); and 

 LeslieAnn Weekes (Technical Editor, CSA Ocean Sciences Inc.).

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German, J.M. Brooks, H.H. Roberts, W. Shedd, C.M. Reddy and C.R. Fisher. 2012. Impact of the Deepwater Horizon 

oil spill on a deep-water coral community in the Gulf of Mexico. Proceedings of the National Academy of Sciences

(Early Edition). doi: 10.1073/pnas.1118029109. Website accessed on October 1, 2012. 

http://www.pnas.org/content/early/2012/03/23/1118029109.full.pdf+html?sid=56e8cdfe-2830-43f8-9d08-

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April 29, 2013. http://www.bringbackthecranes.org/technicaldatabase/recovery/wc_nos_02to11.html

Wiese, F.K., W.A. Montevecchi, G.K. Davoren, F. Huettmann, A.W. Diamond, and J. Linke. 2001. Seabirds at risk around 

offshore oil platforms in the north-west Atlantic. Mar. Poll. Bull. 42(12):1,285-1,290. 

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Page 169 Public Information Copy
Witherington, B.E. 1997. The problem of photopollution for sea turtles and other nocturnal animals, pp. 303-328. In: 

J.R. Clemmons and R. Buchholz (eds.), Behavioral Approaches to Conservation in the Wild. Cambridge University 

Press, Cambridge, England. 

Würsig, B., S.K. Lynn, T.A. Jefferson, and K.D. Mullin. 1998. Behaviour of cetaceans in the northern Gulf of Mexico 

relative to survey ships and aircraft. Aquatic Mammals 24:41-50. 

Würsig, B., T.A. Jefferson, and D.J. Schmidly. 2000. The Marine Mammals of the Gulf of Mexico. Texas A&M University 

Press, College Station, TX. 232 pp. 

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SECTION 19: ADMINISTRATIVE INFORMATION

A. Exempted Information Description (Public Information Copies Only) 

The following attachments were excluded from the public information copies of this plan: 

Section 1B OCS Plan Information form – Bottom hole locations & proposed total depth 

Section 2J Blowout Scenario – confidential information for NTL 2010 N06 calculation 

Section 3A Geologic Description 

Section 3B Structure Contour Maps 

Section 3C Interpreted 2D or 3D seismic line(s)

Section 3D Cross Section(s) 

Section 3E Stratigraphic Column with Time vs. depth table 

Section 3G High-Resolution Seismic Lines & Top Hole Progs 

B. Bibliography 

CSA Environmental Impact Analysis 

Fugro-McClelland Marine Geosciences, Inc, Shallow Hazards Report, Blocks 808, 809, and 853, Mississippi 

Canyon Area, Gulf of Mexico (for Exxon), Report No. 0201-1760, dated November 6, 1992. Data includes: Air 

Gun, subbottom profiler, echosounder 

Fugro-McClelland Marine Geosciences, Inc, Shallow Hazards Report, Blocks 808, 809, 810 and 853, Mississippi 

Canyon Area, Gulf of Mexico, Report No. 0201-1412, dated July 10, 1991. Data includes: Sparker, minisparker, echosounder, deep-towed Side Scan Sonar, Sub-Bottom Profiler 

Shell Offshore, Inc, Shallow Hazards Report, Blocks 810 and 854, Mississippi Canyon Area, Gulf of Mexico, 

dated November, 1988. Data includes: Sparker, mini-sparker, echosounder, deep-towed Side Scan Sonar, 

Sub-Bottom Profiler 

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

Canyon Area, Project No. 083986-084109, dated February 2009. Data includes: AUV side-scan sonar and 

sub-bottom profiler. 

Shell’s Regional OSRP (2013)

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