Shell Offshore Inc

P. O. Box 61933

New Orleans, LA 70161-1933

United States of America

Tel +1 504 728 7215

Fax +1 504 728 0778

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

Email sylvia.bellone@shell.com

 June 3, 2011 

Ms. Liz Peuler, Chief 

Bureau of Ocean Energy Management, 

Regulation and Enforcement 

Office of Field Operations 

1201 Elmwood Park Boulevard 

New Orleans, LA 70123-2394 

 

Attn: Plans Section - MS 5231 

SUBJECT: Initial Exploration Plan 

 OCS-G 07957, Mississippi Canyon Block 762 

 OCS-G 24112, Mississippi Canyon Block 805 

 OCS-G 07962, Mississippi Canyon Block 806 

 Offshore Louisiana 

Gentlemen: 

 

In compliance with 30 CF R 250.103 and NTLs 2010 N-06, 2009-G27 and 2008-G04, giving Exploration 

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

Locations M, N, O, P, Q, R, S & T. Drilling could commence as early as July 1, 2011. 

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

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

and excluded from the Public Information Copies of this submittal. 

The cost recovery fee for this project is $27,536 and a receipt of payment is included in the confidential 

plan (Pay.gov Tracking ID 25321TKL). 

Should you require additional information, please contact me as indicated above. 

Kind regards 

Sylvia A. Bellone 

 
 

SHELL OFFSHORE INC. 

Initial Exploration Plan 

for 

Mississippi Canyon Block 805

OCS-G 24112 

Including activity in 

Mississippi Canyon Block 762 & 806

OCS-G 07957 & OCS-G 07962

PUBLIC INFORMATION 

PREPARED BY: 

Sylvia A. Bellone 

 Regulatory Specialist 

504.728.7215 

Sylvia.bellone@shell.com

 
Initial Exploration Plan 

Mississippi Canyon Block 805

OCS-G 24112

Offshore Louisiana 

Table of Contents 

1. Plan Contents 

2. General Information 

3. Geological and Geophysical 

4. H2S 

5. Mineral Resource Conservation 

6. Biological, Physical and Socioeconomic Information 

7. Waste and Discharge Information 

8. Air Emission Information 

9. Oil Spill Information 

10. Environmental Monitoring 

11. Lease Stipulations 

12. Environmental Mitigation Measures 

13. Related Facilities and Operations Information 

14. Support Vessels and Aircraft 

15. Onshore Support Facilities Information 

16. Sulphur Operations 

17. Coastal Zone Management Act Information 

18. Environmental Impact Analysis 

19. Administrative Information 

 

 

 

 
SECTION 1: PLAN CONTENTS

A. PLAN CONTENTS

Lease OCS-G 24112, Mississippi Canyon Block 805, was acquired in Lease Sale #812 held on March 20, 

2001. This lease will expire July 31, 20 12. Le ases OCS-G 07957 and OCS-G 07962 were acquired in 

Lease Sale #98 on May 1985 and are being held by production. This Plan will be for the initial batch 

setting and drilling and completion of wells M through T utilizing a DP semisubmersible and/or a drill ship. 

There are no anchors associated with this Plan. The portion of the blocks that well ac tivities will take 

place on is outside of the Unit No. 754393002. 

LOCATION

Included are the following attachments: 

 Attachment A.1: OCS Plans Information Forms 

 Attachment A.2: Well Location Plats 

B. SAFETY AND POLLUTION PREVENTION FEATURES

The proposed rigs, the Noble Bully 1 and the Noble Jim Day, 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 dri lling operations will be co nducted under the provisio ns of 30 CFR, Part 250, 

Subpart D, and other ap plicable regulations and notices, inclu ding those reg arding the avoidance of 

potential drilling hazards and safety and pollution prevention control. Such measures as inflow detection 

and well control, monitoring for loss of c irculation and seepage loss, and casing design wi ll be our primary 

safety measures. Primary pollutio n prevention measures are contaminated an d non-contaminated drain 

system, mud drain system, and oily water processing. 

C. Storage Tanks - Bully 1 or similar Drill Ship 

Type of Storage 

Tank 

Type of 

Facility 

Tank 

Capacity 

(bbls) 

N0. 

Number 

of 

Tanks 

Total 

Capacity 

(bbls) 

Fluid 

Gravity (API) 

Diesel Tank Drilling Rig 1,392 23 32,016 Marine Diesel (0.91 

SG) 

Lube Oil Tank Drilling Rig 347.95 2 695 Lube Oil (0.91 SG) 

Dirty Oil Drilling Rig 549.81 2 1,099 Dirty Oil (0.91 SG) 

Base Oil Drilling Rig 4,331 1 4,331 Synthetic Base Oil & 

Chemicals 
Storage Tanks - Jim Day or similar semi-submersible 

Type of Storage Tank Type of

Facility 

Tank

Capacity 

(bbls) 

Number 

of

Tanks 

Total

Capacity 

(bbls) 

Fluid

Gravity (API) 

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 stowage 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) 

D. Pollution Prevention Measures

Pursuant to NTL No. 200 8-G04 the proposed oper ations 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 in 1(c) above. 

F. Additional Measures

 

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

The discussion around no harm t o people or environment is a key mindset. All per sonnel are 

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

• 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. 

• PM’s of rig equipment include 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 st orage areas, fuel vents, 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 u tilizes Envirorite environmentally friendly hydraulic fluid as opposed to 

hydraulic oil. 

• Shell has obtained ISO14001 certification. 
 U. S. Department of the Interior OMB Control Number: 1010-0049 

Minerals Management Service OMB Approval Expires: December 3, 2010 

OCS PLAN INFORMATION FORM 

General Information 

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

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

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

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

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

Lease(s): OCS-G 7957, 24112, 

7962 

Area: MC Block(s): 762,805, 

806 

Project Name (If Applicable):West Boreas 

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

Boothville 

Distance to Closest Land (Miles): 50 

Description of Proposed Activities (Mark all that apply)

X Exploration drilling Development drilling 

X Well completion Installation of production platform 

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

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

Installation of subsea wellheads and/or manifolds Commence production 

Installation of lease term pipelines Other (Specify and describe) 

Have you submitted or do you plan to submit a Conservation Information Document to accompany this 

plan? 

X Yes No 

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

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

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

Have all of the surface locations of your proposed activities been previously reviewed and approved by 

MMS? 

X* Yes No 

Tentative Schedule of Proposed Activities 

Proposed Activity Start Date End Date No. of Days

See Next Page 

*Note: All proposed surface locations are within 500’ of the previously approved “G” 

Location in SEP, S-07273, approved 12/16/2008 

 

Description of Drilling Rig Description of Production Platform 

 Jackup X Drillship Caisson X 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 semi, Bully I 

drillship, or similar rigs. 

 Spar Other (Attach Description) 

Description of Lease Term Pipelines 

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

N/A 

 

MMS Form MMS-137 (August 2003) Page 1 of 10 PUBLIC INFORMATION 

 
Tentative Schedule of Proposed Activities 

Proposed Activity Start Date End Date No. of Days

Batch Set M through T wells* 7/1/2011 9/29/2011 90 

Drill Well N* 9/30/2011 3/2/2012 154 

Drill O 10/1/2012 1/29/2013 120 

Drill P 1/30/2013 5/30/2013 120 

Complete N 5/31/2013 7/30/2013 120 

Complete O 7/31/2013 9/29/2013 60 

Complete P 9/30/2013 11/29/2013 60 

Drill Q 11/30/2013 3/30/2014 60 

Complete QA 3/31/2014 5/30/2014 60 

Drill R 5/31/2014 9/28/2014 120 

Complete R 9/29/2014 11/28/2014 60 

Drill M 11/29/2014 3/29/2015 120 

Complete M 3/30/2015 5/29/2015 60 

Drill S 5/30/2015 9/27/2015 120 

Complete S 9/28/2015 11/27/2015 60 

Drill T 11/28/2015 3/27/2016 120 

Complete T 3/28/2016 5/27/2016 60 

*=Noble Jim Day 

Page 2 of 10 
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): M Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07957 

Area Name Mississippi Canyon 

Block No. 762 

Blockline 

Departures 

(in feet)

N/S Departure: 926’ FSL 

E/W Departure: 1386.' FWL 

Lambert X-Y 

coordinates 

X: 904266 

Y: 10233566 

Latitude/ 

Longitude

Latitude 28° 10’51.68 

Longitude -89° 17’ 7.88 

TVD (Feet): MD (Feet): Water Depth (Feet): 3140’ 

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

) 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. Chapter 35) 

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

Development Operations Coordination Document submitted for MMS approval. We use the information to 

facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to 

respond to, a collection of information unless it displays a currently valid Office of Management and Budget 

Control Number. The use of this form is voluntary. The public reporting burden for this form is included in the 

burden for preparing Exploration Plans and Development Operations Coordination Documents. We estimate 

that burden to average 580 hours per response, including the time for reviewing instructions, gathering and 

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

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

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

MMS Form MMS-137 (August 2003) PUBLIC INFORMATION Page 3 of 10 
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): N Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07957 

Area Name Mississippi Canyon 

Block No. 762 

Blockline 

Departures 

(in feet)

N/S Departure: 985’ FSL 

E/W Departure: 1340' FWL 

Lambert X-Y 

coordinates 

X: 904220 

Y: 10233625 

Latitude/ 

Longitude

Latitude 28° 10’52.26 

Longitude -89° 17’ 8.40 

TVD (Feet): MD (Feet): Water Depth (Feet): 3140’ 

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

) 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. Chapter 35) 

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

Development Operations Coordination Document submitted for MMS approval. We use the information to 

facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to 

respond to, a collection of information unless it displays a currently valid Office of Management and Budget 

Control Number. The use of this form is voluntary. The public reporting burden for this form is included in the 

burden for preparing Exploration Plans and Development Operations Coordination Documents. We estimate 

that burden to average 580 hours per response, including the time for reviewing instructions, gathering and 

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

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

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

MMS Form MMS-137 (August 2003) PUBLIC INFORMATION Page 4 of 10 

 
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): O Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07957 

Area Name Mississippi Canyon 

Block No. 762 

Blockline 

Departures 

(in feet)

N/S Departure: 1104’ FSL 

E/W Departure: 1352' FWL 

Lambert X-Y 

coordinates 

X: 904232 

Y: 10233744 

Latitude/ 

Longitude

Latitude 28°18’53.44 

Longitude -89°17’8.30 

TVD (Feet): MD (Feet): Water Depth (Feet): 3148’ 

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

) 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. Chapter 35) 

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

Development Operations Coordination Document submitted for MMS approval. We use the information to 

facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to 

respond to, a collection of information unless it displays a currently valid Office of Management and Budget 

Control Number. The use of this form is voluntary. The public reporting burden for this form is included in the 

burden for preparing Exploration Plans and Development Operations Coordination Documents. We estimate 

that burden to average 580 hours per response, including the time for reviewing instructions, gathering and 

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

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

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

MMS Form MMS-137 (August 2003) PUBLIC INFORMATION Page 5 of 10 
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): P Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07957 

Area Name Mississippi Canyon 

Block No. 762 

Blockline 

Departures 

(in feet)

N/S Departure: 1154’ FSL 

E/W Departure: 1408' FWL 

Lambert X-Y 

coordinates 

X: 904288 

Y: 10233794 

Latitude/ 

Longitude

Latitude 28°10’53.94 

Longitude -89°17’7.69 

TVD (Feet): MD (Feet): Water Depth (Feet): 3145’ 

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

) 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. Chapter 35) 

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

Development Operations Coordination Document submitted for MMS approval. We use the information to 

facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to 

respond to, a collection of information unless it displays a currently valid Office of Management and Budget 

Control Number. The use of this form is voluntary. The public reporting burden for this form is included in the 

burden for preparing Exploration Plans and Development Operations Coordination Documents. We estimate 

that burden to average 580 hours per response, including the time for reviewing instructions, gathering and 

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

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

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

MMS Form MMS-137 (August 2003) PUBLIC INFORMATION Page 6 of 10 
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): Q Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07957 

Area Name Mississippi Canyon 

Block No. 762 

Blockline 

Departures 

(in feet)

N/S Departure: 1125’ FSL 

E/W Departure: 1477’ FWL 

Lambert X-Y 

coordinates 

X: 904357 

Y: 10233765 

Latitude/ 

Longitude

Latitude 28°10’53.67 

Longitude -89°17’ 6.90 

TVD (Feet): MD (Feet): Water Depth (Feet): 3145’ 

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

) 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. Chapter 35) 

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

Development Operations Coordination Document submitted for MMS approval. We use the information to 

facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to 

respond to, a collection of information unless it displays a currently valid Office of Management and Budget 

Control Number. The use of this form is voluntary. The public reporting burden for this form is included in the 

burden for preparing Exploration Plans and Development Operations Coordination Documents. We estimate 

that burden to average 580 hours per response, including the time for reviewing instructions, gathering and 

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

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

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

MMS Form MMS-137 (August 2003) PUBLIC INFORMATION Page 7 of 10 

 
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): R Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07957 

Area Name Mississippi Canyon 

Block No. 762 

Blockline 

Departures 

(in feet)

N/S Departure: 949’ FSL 

E/W Departure: 1457' FWL 

Lambert X-Y 

coordinates 

X: 904337 

Y: 10233589 

Latitude/ 

Longitude

Latitude 28°10’ 51.94 

Longitude -89°17’ 7.09 

TVD (Feet): MD (Feet): Water Depth (Feet): 3152’ 

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

) 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. Chapter 35) 

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

Development Operations Coordination Document submitted for MMS approval. We use the information to 

facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to 

respond to, a collection of information unless it displays a currently valid Office of Management and Budget 

Control Number. The use of this form is voluntary. The public reporting burden for this form is included in the 

burden for preparing Exploration Plans and Development Operations Coordination Documents. We estimate 

that burden to average 580 hours per response, including the time for reviewing instructions, gathering and 

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

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

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

MMS Form MMS-137 (August 2003) PUBLIC INFORMATION Page 8 of 10 
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): S Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07957 

Area Name Mississippi Canyon 

Block No. 762 

Blockline 

Departures 

(in feet)

N/S Departure: 944’ FNL 

E/W Departure: 1492' FWL 

Lambert X-Y 

coordinates 

X: 904372 

Y: 10233584 

Latitude/ 

Longitude

Latitude 28°10’51.87 

Longitude -89°17’ 6.70 

TVD (Feet): MD (Feet): Water Depth (Feet): 3140’ 

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

) 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. Chapter 

35) requires us to inform you that MMS collects this info rmation as part of a n applicant’s Exploration Plan or 

Development Operations Coordination Document submitted for MMS approval. We u se the information to 

facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not requi red to 

respond to, a collection of information unless it di splays a currently valid Off ice of Management and Budget 

Control Number. The use of this form is voluntary. The public reporting burden for this for m is included in the 

burden for preparing Exploration Plans and Development Operations Coordination Documents. We estimate that 

burden to average 580 hours per r esponse, including the time for reviewi ng instructions, gathering and 

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

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

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

MMS Form MMS-137 (August 2003) PUBLIC INFORMATION Page 9 of 10 
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): T Subsea Completion 

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

Surface Location Bottom-Hole Location (For Wells) 

Lease No. OCS-G 07957 

Area Name Mississippi Canyon 

Block No. 762 

Blockline 

Departures 

(in feet)

N/S Departure: 980’ FNL 

E/W Departure: 1382' FWL 

Lambert X-Y 

coordinates 

X: 904262 

Y: 10233530 

Latitude/ 

Longitude

Latitude 28°10’51.32 

Longitude -89°17’7.92 

TVD (Feet): MD (Feet): Water Depth (Feet): 3140’ 

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

) 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. Chapter 35) 

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

Development Operations Coordination Document submitted for MMS approval. We use the information to 

facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to 

respond to, a collection of information unless it displays a currently valid Office of Management and Budget 

Control Number. The use of this form is voluntary. The public reporting burden for this form is included in the 

burden for preparing Exploration Plans and Development Operations Coordination Documents. We estimate 

that burden to average 580 hours per response, including the time for reviewing instructions, gathering and 

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

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

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

MMS Form MMS-137 (August 2003) PUBLIC INFORMATION Page 10 

of 10 

 
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SHELL

BLK. 805

OCS-G24112

SHELL ET AL

BLK. 806

OCS-G07962

SHELL ET AL

BLK. 762

OCS-G07957

LLOG

BLK. 761

OCS-G28025

S

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M N

R

Q

3150

3150

3150

3100

3100

3100

3200

3200

3200

3250

3300

3000

3350

3400

3050

3050

3450

3050

X=902,880

Y=10,232,640

Mississippi Canyon Block 762

OCS-G07957

Proposed Well Locations

With Bathymetry 3

...\CAD_NewOrleans\Maps\Permit Plats\W Boreas-S Deimos\W Boreas-S Deimos Proposed Wells with Bathymetry.mxd

Projection: NAD_1927_UTM_Zone_16N

Linear Unit: Foot_US

Shell Exploration and Production Co.

0 1,000 2,000 4,000 6,000

Feet

") Proposed Surface Locations

M 1386' FWL and 926' FSL of Blk. 762

 X=904,266' Y=10,233,566'

N 1340' FWL and 985' FSL of Blk. 762

 X=904,220' Y=10,233,625'

O 1352' FWL and 1104' FSL of Blk. 762

 X=904,232' Y=10,233,744'

P 1408' FWL and 1154' FSL of Blk. 762

 X=904,288' Y=10,233,794'

Q 1477' FWL and 1125' FSL of Blk. 762

 X=904,357' Y=10,233,765'

R 1457' FWL and 949' FSL of Blk. 762

 X=904,337' Y=10,233,589'

S 1492' FWL and 944' FSL of Blk. 762

 X=904,372' Y=10,233,584'

T 1382' FWL and 890' FSL of Blk. 762

 X=904,262' Y=10,233,530'
SECTION 2: GENERAL INFORMATION

A. Application and Permits

Applications/Permits Issuing Agency Status 

Rig Move BOEMRE Pending 

CZM State of LA Pending 

B. Drilling Fluids - Noble Bully 1 & Noble Jim Day

 See table 7A. 

C. Production

Production rates are applicable in DOCD’s, not Exploration Plans. 

D. Oil Characteristics

Oil characteristics are applicable in DOCD’s, not Exploration Plans; therefore they are omitted from this 

Plan. 

E. New or unusual technology

A Continuous Circulating System i s being evaluated to be used in the last two intervals in order to minimize 

pressure surges to the formation and to main tain ECD’s hyd rostatic pressure on the formation during 

connections. 

F. Bonding

The bond re quirement for the activit ies proposed in th is supplemental EP ar e satisfied by an area-wide bon d 

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

Surety Bonds;” and National NTL No. 2003-N06, “Supplemental Bond Procures.” 

G. Oil Spill Financial Responsibility (OSFR)

Shell Offshore Inc (SOI), MMS Operator Number 0689, has demonstrated oil spill f inancial responsibility for the 

facilities proposed in the EP according to 30 CFR part 253, and NTL No. 99-N01, “Guidelines for Oil Spill Financial 

Responsibility for Covered Facilities.” 

H. Deepwater well control statement

Shell Offshore Inc (SOI), MMS Operator Num ber 0689, has the financial capability to drill a relief well and conduct 

other emergency well control operations. 

I. Suspension of Production

Suspension of Production is not applicable to exploration plans. 

 
J. Blowout scenario

Summary 

Attached is Shell Offshor e’s (Shell) respon se to th e Bureau of Ocean En ergy Management, Regulation and 

Enforcement’s (BOEMRE) Notice to Lessees (NTL) No. 2010-N06. The information provided in Shell’s NTL 2010-

N06 response includes well resul ts and survey data th at are hi ghly confidential and commercially sensitive. 

These well r esults and survey data were analyzed and presented using S hell proprietary information and 

processes. The confidential sections will be omitted from the public information copies. 

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

/containment, and recov ery. Shell believes th at the best w ay to manage blowouts is to prevent the m from 

happening. Significant effort goes into design and execution of wells and into building and maintainin g staff 

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

reliability of our well systems. We are actively c omplying with NTL No.201 0-N05, Drilling Safety Rule, and 

Workplace Safety Rule. 

Shell is investing in R&D to improve containment systems. As outlined in Shell’s Oil Spill Response Plan (OSRP), 

and detailed in EP Section 9a (ii), Shell has contracts with Oil Spill Removal Organizations (ORSOs) to provide 

the resources necessary to respond to this Worst Case Discharge (WCD) scenario. 

The Worst Case Discharge (WCD) blowout scenario for West Boreas is calculated for the MC-805 WB-A loc ation 

(well location N in corresponding sup plemental exploration plan) of the Al uminum Sand and based on the 

guidelines outlined in NTL No. 2010-N06 along with su bsequent Frequently Asked Questi ons (FAQ). Shell’s 

Regional OSRP (October 2010) is based on MC-391 C (Appomattox) as the Worst Case Discharge well. The MC805 WB-A well has a discharge volume estimate of 449,000 bbl for the first d ay, versus the MC-391 C first day 

discharge of 405,000 bbl. However, MC-805 WB-A well has a first 30-day average daily rate estimate of 359,000 

bopd, versus the MC-391 C first 30-day average daily rate estimate of 371,000 bopd. The MC-805 WB-A’s first 

30-day average daily rate is lower than MC-391 C’ s because it is a smaller accumulation within a smaller 

reservoir/aquifer tank size; therefore it has a higher depletion rate. Sh ell’s Regional OSRP (October 2010) 

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

Regional OSRP (October 2010) is designed to contain and respond to a spill that meets or exceeds the MC 805 

WB-A WCD. This WCD does not take into acc ount potential flow mitigatin g factors such as well bri dging, 

obstructions in wellbore, reservoir barriers, or early intervention. 

. 

Uncontrolled blowout (volume first day) 449,000 bbl 

Uncontrolled blowout rate (first 30-days average daily rate) 359,000 bopd 

Duration of flow (days) based on relief well 150 days 

Total volume of spill (bbls) for 128 days 25.9 MMBO 

Table 1 Worst Case Discharge Summary 

The West Boreas and South Deimos discoveries are located approximately 44 miles east-southeast of the 

nearest shoreline in the Gulf of Mexi co (GOM), in wate r depths of approxi mately 3140 feet (ft) acr oss the 

discovery. 

Detailed reservoir models have been constructed for the West Boreas and South Deimos discoveries. The static 

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

these discovery wells. A table of the available data co llected from these analogue wells is included in the 

attachment. 

Shell’s seismic interpretation used for constructing the West Boreas reservoir model is based on high quality 

anisotropic ocean bottom nodes - wide azimuth (OBS WAZ) seismic survey. Seismic profiles through the 

proposed WB-A well target and offset wells are included in the attachment. This survey has an excellent well tie 

at all three of the well penetrati ons within the Boreas Su b-Basin, thus giving a high confidence interpretation . 

The seismic interpretation was used for constructing the structure and stratigraphic framework of the model as it 

was extrapolated away from the existing well control. Due to the excellent well ties to seismic, the amplitude 
extraction maps were correlated to the reservoir characteristics of each well an d extrapolated across the entire 

area of the Aluminium sand in the basin. These seismic extraction maps were then imported into Petrel for 

construction of the West Boreas static reservoir m odel. The static model was then imported into C MG for 

reservoir simulation. The WB-A well target wa s simulated in this CMG model. Theref ore the resulting WCD 

calculation included in this document is based on th e reservoir properties indicated from th e reservoir model at 

the WB-A target location. This document is a summary of the results of this modelling. Electronic copies of the 

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

The West Boreas Aluminium reservoir sand has been sei smically interpreted to be cut by at least four faults, 

which separate it into four fault blocks. These faults have been incorporated into the West Boreas static and 

dynamic reservoir model. Shell’s internal fault analysis indicates that there is a high likelihood that porti ons of 

these faults may seal an d isolate po rtions of the Aluminium reservoir. However for the West Bor eas WCD 

scenario, the model considered the maximum drainage area and left all internal faults non-sealing. 

The WCD blowout scenario was calculated for the WB-A penetration of the Aluminum Sand and based on the 

guidelines outlined in NTL No. 2010-N6 and subsequent Frequently Asked Questions (FAQ) documents. 

1) Purpose 

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

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

to determine the WCD and the measures taken to firstly enhance the ability to prevent a blowout and secondly 

to respond and manage a blowout scenario if it were to occur. These calculations are based on best te chnical 

estimates of subsurface parameters that are derived from the offset B oreas, West Boreas and South Deimos 

wells, and seismic. These parameters are better than or consistent with the estimates used by Shell to justify the 

investment. Therefore, these assumed parameters were used to calculate the WCD. They do not reflect 

probabilistic estimates. 

2) Background 

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

as requested by NTL No. 2010-N06 in response to the explosion and sinking of the Mobile Off shore Drilling Unit 

(MODU) Deepwater Horizon and the resulting sub sea well blowout and recovery operations of the exp loration 

well at the MC-252 Macondo location. 

3) Information Requirements 

a) Blowout scenario 

All eight locations of the proposed Boreas EP supplement were assessed for Worst Case Discharge. The 

WB-A (well location N) well represented the high est flow potential. The WB-A well was drilled to the 

Aluminum Sand as outlined in the Geological and Geophysical Information Section of the Supplemental 

EP, and described above, utilizing a typical su b-sea wellhead system, c onductor, surface and 

intermediate casing pr ogram, and using a MOD U rig with a marine riser and sub -sea Blow Ou t 

Preventer. A hydrocarbon influx and a well control event are modeled to occur from the Aluminum Sand 

during a trip out of the hole. The simulated blow-out model results in unrestricted flow from the well at 

the seafloor which represents the worst case discharge, no restrictions in the wellbore, failure/loss of the 

sub-sea BOP and a blow-out to the seabed. 

 
b) Estimated flow rate of the potential blowout 

Category EP 

Type of Activity Drilling 

Facility Location (area/block) MC-762 

Facility Designation MODU 

Distance to Nearest Shoreline (miles) 51 Statute miles 

Uncontrolled blowout (volume first day) 449,000 bbl 

Uncontrolled blowout rate (first 30-days average daily rate) 359,000 bopd 

Table 2 Estimated Flow Rates of a Potential Blowout 

c) Total volume and maximum duration of the potential blowout 

Duration of flow (days) 150 days total duration to drill relief well 

(14 days to contract/mob rig) 

Total volume of spill (bbls) 25.9 MMBO Note: based on Petrel static and CMG Dynamic reservoir 

models 

Table 3: Estimated Duration and Volume of a Potential Blowout 

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

between the first 24-hour volume and 30-day average rate. The total volume calculated until a well i s 

killed in a potential blowout further de monstrates this decline. At very short times, e.g. during the first 

24 hours, the pressure profile in the reservoir change s from the moment when a well first starts flowing 

to a ps eudo-steady state pressure profile with time, and as a result the r ate declines. A t somewhat 

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

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

and form the basis of the NTL No. 2010-N06 estimates for 24-hour and 30-day rates as well a s 

maximum duration volumes. 

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

 Omitted from Public Information Copies. 

e) Potential for the well to bridge over 

Mechanical failure/collapse of the bor ehole in a blowout scenario is influen ced by several factor s 

including in-situ stress, r ock strength and fluid velocities at the sandface. B ased on the nodal an alysis 

and reservoir simulation models outlined above, a seabed blowout would create a high drawdown at the 

sand face. Given the substantial fluid velocities inhe rent 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 th at 

the borehole may fail/collapse/bridge over within the span of a few days, significantly reducing outflow 

rates. However, this WCD scenario does not include any bridging. 

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, c onservative well 

design, prudent operations practices, competency of personnel, and strong HSE focus. C ollectively, 

these constitute a robust system making blowouts extremely rare events. 

 
Intervention Devices: Notwithstanding these facts, the main scenario for recovery from a blowou t 

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 contr acted rig fleet in the GO M will have redundancies meeting the Interim Final 

Drilling Safety Rule with respect to Remotely Operated Vehicle (ROV) hot stab capabilities, a d eadman 

system, and an autoshear system. 

Shell will be using dynami cally positioned rigs to drill the West Boreas/South Deimos wells. These rig s 

have two shearing rams in the BOP for added redundancy. 

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

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

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

page 17 of the Decision Memorandum dated October 1, 2010). Shell is further analyzing these advances 

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

deepwater control incident. 

Pursuant to NTL No. 201 0-N10 Shell will provide a dditional information regarding our c ontainment 

capabilities in a subsequent filing. 

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

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

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

by a total of four to six MODU rigs in 2011 – 2015 timeframe. The dynamically positioned rigs under 

contract, the Noble Danny Adkins, the Noble Jim Day, and the Noble Bully 1, will be the preferred rigs 

for blowout intervention work. However, moored rigs can also be used in some scenarios. Additionally, 

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

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

secure the appropriate rig . Shell’s current contracted rigs capable of operating at West Boreas water 

depths and reservoir depths without technical constraints are in the following table: 

Deepwater Nautilus moored semi 

Noble Jim Thompson moored semi 

Noble Jim Day dynamically positioned 

semi. 

Noble Danny Adkins dynamically positioned 

semi. 

Bully 1** dynamically positioned 

drill ship 

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

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

**Bully 1 estimated arrival Q4, 2011. 

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

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

fleet. The list of rigs cap able of operating at West Boreas is tabled above. It is expected to take an 

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

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

The relief well will take approximately 102 days to drill down to the last casing string above the blow-out 

zone plus +/- 30 days for precision ranging activity to intersect the blow-out well bore. Total time to 

drill a relief well would be ~150 days for West Boreas wells. 

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

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

on critical path. Shell has 3 deepwater anchor handlers, the Laney, Dino and Ross Chouest, on long term 

contract to support its moored rigs. 
The closet TLP to the West Boreas / South Deimos subsea development is the Mars “A” TLP. Currently 

there are no slots available for drilling a new well (relief well) off the TLP. Directional design for a relief 

well off the Mars “A” TLP would be very complex and the current rig on the Mars “A” TLP would be 

incapable of drilling the well. Therefore the quickest way to initiate the drilling of a relief is with another 

MODU drilling unit. 

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 m easures employed by Shell with the g oal of no h arm to peopl e or the environ ment. The 

Macondo incident has hig hlighted the importance of these pract ices. The lessons learned from the 

investigation are, and will continue to be, incorporated into our operations. 

Standards: Shell’s well design and op erations adhere to intern al corporate standards, the Code of 

Federal Regulations, and industry standards. A r obust management of change process is in place to 

handle un-defined or exc eption 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 th at prevention of m ajor incidents is best m anaged through the 

systematic identification and mitigation process (Safety and Environmental Management System, SEMS). 

All Shell contracted rigs in the GOM have a SEMS. The SEMS requires both the owner and contractors to 

systematically identify the risks in drilling operatio ns and align plans to m itigate 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 functi onal experts (internal and ex ternal) to examine the 

well design at the conceptual and detailed design stages fo r robustness before making a 

recommendation to the m anagement 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 intern al 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 (D WOP) 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 

NTL No. 201 0-N05 and al l applicable rules and reg ulations, including interim final rules. Shell wor ks 

closely with rig contractors to ensure proper upkeep of all rig equipment, which meets or exceeds the 

strictest of Shell, industry, or regulatory requir ements. 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 West Boreas. 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 th e tools are 

monitored and interpreted real time against prognosis to provide early warning of abnormal pressures 

and allow measures to be taken to progress the well safely. 

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

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

in the returni ng 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 penetr ated or i s about to penetrate a hydrocarbon-b earing 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 hydroc arbons. The mud logging personnel are in close 

communication with both the drilling foreman and Shell representative to report any observed anomalies 

so appropriate action can be taken.

 
Remote Monitoring: The Real Time Operating Center has been used by S hell to compl ement and 

support traditional rig-site monitoring since 2003. Well site operation s are li ved virtually by onshor e 

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

same real time well control indicators monitored b y the rig per sonnel are watched by the monitoring 

specialist for an added layer of redundancy. 

Competency and Behavior: A str uctured training program for Well Engineers and Foreman is 

practiced, which includes internal professi onal examinations to verify com petency. Other industry 

training in well contr ol, such as by Internatio nal 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, pr e-job analysis, behavior based safety, DWOPs, au dits), 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 i s part of the wider emergency 

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

situation. Resources are dedicated to these sy stems and drills ar e run frequently to test preparedness 

(security, medical, oil spil l, and hurricane). Thi s same framework is activ ated and tested durin g 

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 th eir roles in the response, defining informati on requirements, 

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

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

activity checklists, a roster of equipment and servic es, initial information gathering forms, a generi c 

description of relief well d rilling, strategy and guide lines, intervention techniques and equipment, site 

safety management, exclusion zones, and re-boarding. 

As set forth in 3f of this document, Shell is cu rrently analyzing recent advances in c ontainment 

technology and equipmen t and will incorporate th em as th ey become available and is a founding 

member of MWCC. 

k) Arrangements for drilling a relief well 

The size of the Shell contracted rig fleet in the GOM from 2010-2015 ensures that there is adequate well 

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

available within Shell, diverted from their active roles elsewhere. Resources from other operators can 

also be lever aged should the need arise. Gener ally, relief well plans will mirror the blowou t well, 

incorporating any learning on well design based on root cause analysis of the blowout. A generic relief 

well description is outlined in the WCCP. 

l) Assumptions and calculations used in approved or proposed OSRP 

Shell has submitted MC-391 C (Appomattox) as the new exploratory worst-case scenario to the BOEMRE 

for inclusion in our Regional OSRP. 

Shell has designed a response program (Regional OSRP October 2010) based upon a regional capability 

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

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

regulations. The Regional OSRP presents sp ecific information on the respon se program that includes a 

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

the strategies and tactics used to imp lement effective and sustained spill containment an d recovery 

operations. 

 
SECTION 3: GEOLOGICAL AND GEOPHYSICAL INFORMATION

A. Geological description

Omitted from Public Information Copies 

B. Structure Contour Map(s)

C. Omitted from Public Information Copies 

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

E. Omitted from Public Information Copies 

F. Geological Structure Cross-section(s)

G. Omitted from Public Information Copies 

H. Shallow Hazards Report

See 3f below. 

F. Shallow Hazards Assessment

History

Shell submitted shallow hazard Report No. 1188-1062 prepared by Fugro-McClelland, on April 26, 1988, and 

Report No. 0201-1387 also prepared by Fugro-McClelland, on April 20, 1992. On September 10, 1993, the 

MMS approved drilling in the Mississippi Canyon Unit (consisting of wells in MC 763, 806 and 807). 

Shell submitted a Supplemental EP and Shallow Hazard Report No. 0403-643 prepared by Geosciences Earth 

and Marine Services, Inc. (GEMS) dated July 31, 2003, covering Mississippi Canyon Block 762, Proposed 

Locations D, E, and F and the associated anchor patterns. 

Shell submitted another Supplemental EP for Proposed Locations G, H, and I in MC 762 and Proposed 

Locations J, K and L in MC 806. This Supplemental EP was approved December 16, 2008. 

Shell is now submitting another Supplemental EP for Proposed Locations M, N, O, P, Q, R, S and T in MC 762. 

Proposed Locations

Proposed Surface Locations M, MC 762: 

 X = 904,266 1386’ FWL 

 Y = 10,233,566 926’ FSL 

Proposed Surface Locations N, MC 762: 

 X = 904,220 1340’ FWL 

 Y = 10,233,625 985’ FSL 

Proposed Location O, MC 762: 

 X = 904,232 1352’ FWL 

 Y = 10,233,744 1104’ FSL 
Proposed Location P, MC 762: 

 X = 904,288 1408’ FWL 

 Y = 10,233,794 1154’ FSL 

Proposed Location Q, MC 762: 

X = 904,357 1477’ FWL 

Y = 10,233,765 1125’ FSL 

Proposed Location R, MC 762: 

 X = 904,337 1457’ FWL 

 Y = 10,233,589 949’ FSL 

Proposed Surface Location S, MC 762: 

 X = 904,372 1492’ FWL 

 Y = 10,233,584 944’ FSL 

Proposed Surface Locations T, MC 762: 

 X = 904,262 1382’ FWL 

 Y = 10,233,530 890’ FSL 

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

Renderings, and Enhanced Surface Renderings with amplitudes applied, and side scan sonar and sub-bottom 

profiler, Mississippi Canyon 762, Proposed Locations appear suitable for the planned activity. 

Dougal Grant Arlette C. Nunez 

Staff Geologist Shallow Hazard Interpreter 
 High-Resolution Seismic Lines

See attached ESR (Water Bottom & Amplitude). 

Top hole Prognosis & Power Spectrum Drawings have been omitted from PI Copies. 

 H & I Stratigraphic Column with Time vs depth table

Omitted from Public Information Copies 

SECTION 4: Hydrogen Sulfide 

A. Concentration 

0 ppm 

B. Classification

Based on CFR 250.490 (c), SOI requests that the Regional Supervisor, Field Operations, determine the zones 

in the proposed drilling operations in this plan to be classified as an area where the absence of H2S has been 

confirmed.

C. H2S Contingency Plan

In accordance with 30 CFR 250.490(f) a Contingency Plan was not required for this Lease. 

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. 
Fluid Expulsion 

Feature 
SECTION 5: Mineral Resource Conservation Information

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

required in the case of DOCDs. 
SECTION 6: Biological, Physical, and Socioeconomic Information

A. Chemosynthetic Communities Report

Biological Information

NTL 2009-G40, dated January 27, 2010, for water depths greater than 984 feet 

Mississippi Canyon 762, Proposed Locations M, N, O, P, Q, R, S and T: 

• Features or areas that could support high-density chemosynthetic communities are not

within 2,000 feet of each proposed mud and cuttings discharge location. 

• Features or areas that could support high-density chemosynthetic communities are not

Located within 250 feet of any seafloor disturbance resulting from the use of anchors 

(including those caused by anchors, anchor chains, wire ropes, seafloor template installation, 

and pipeline construction). Seafloor disturbances include all “temporary” 

disturbances caused during mooring operations (e.g., anchor deployment, setting and 

retrieval) as well as those caused by anchoring activities conducted prior to a MODU arriving 

on location (e.g., pre-installation of suction piles and cables, where seafloor impacts are 

much greater while the cables are located on the seafloor prior to being pulled taut and 

attached to the MODU). The generic anchor radius is 9,000’, with an additional buffer of 

1,000’ for a total clearance of 10,000’. 

History

Shell submitted shallow hazard Report No. 1188-1062 prepared by Fugro-McClelland, on April 26, 1988, and 

Report No. 0201-1387 also prepared by Fugro-McClelland, on April 20, 1992. On September 10, 1993, the 

MMS approved drilling in the Mississippi Canyon Unit (consisting of wells in MC 763, 806 and 807). 

Shell submitted a Supplemental EP and Shallow Hazard Report No. 0403-643 prepared by Geosciences Earth 

and Marine Services, Inc. (GEMS) dated July 31, 2003, covering Mississippi Canyon Block 762, Proposed 

Locations D, E, and F and the associated anchor patterns. 

Shell submitted another Supplemental EP for Proposed Locations G, H, and I in MC 762 and Proposed 

Locations J, K and L in MC 806. This Supplemental EP was approved December 16, 2008. 

Shell is now submitting another Supplemental EP for Proposed Locations M, N, O, P, Q, R, S and T in MC 

762. 

Proposed Locations

Proposed Surface Locations M, MC 762: 

 X = 904,266 1386’ FWL 

 Y = 10,233,566 926’ FSL 

Mississippi Canyon 762, Proposed Location M is located in a water depth of approximately 3150 feet. 

Proposed Location M is located near the center of a near-surface ancient slump valley. There is no evidence 

of seafloor or near-surface faulting, slumping, amplitude or fluid expulsion features in the vicinity of 

Proposed Location M. Proposed Location M will not disturb any high-density areas of chemosynthetic 

communities. 
Proposed Surface Location M will be positioned 137 feet southwest of Shell’s previously drilled MC 806-3 

wellsite. Proposed Location M will be positioned 5934 feet southwest of Shell’s previously drilled MC 762 

#3 wellsite. Proposed Location M will be positioned 6066 feet southwest of Shell’s previously drilled MC 

762 #2 wellsite. Proposed Location M will not interfere with these previously drilled wellsites. 

Proposed Location M will be positioned over 1700 feet east of ATP’s flowline and 3450 feet north of Shell’s 

Europe to Mars Flowlines. Proposed Location M will not interfere with these flowlines. Currently, there are 

no other flowlines within the vicinity of Proposed Location M. 

Proposed Surface Locations N, MC 762: 

 X = 904,220 1340’ FWL 

 Y = 10,233,625 985’ FSL 

Mississippi Canyon 762, Proposed Location N is located in a water depth of approximately 3150 feet. 

Proposed Location N is located near the center of a near-surface ancient slump valley. There is no evidence 

of seafloor or near-surface faulting, slumping, amplitude or fluid expulsion features in the vicinity of 

Proposed Location N. Proposed Location N will not disturb any high-density areas of chemosynthetic 

communities. 

Proposed Location N will be positioned 182 feet southwest of Shell’s previously drilled MC 806-3 wellsite. 

Proposed Location N will be positioned 5976 feet southwest of Shell’s previously drilled MC 762 #3 wellsite. 

Proposed Location N will be positioned 6108 feet southwest of Shell’s previously drilled MC 762 #2 wellsite. 

Proposed Location N will not interfere with these previously drilled wellsites. 

Proposed Location N will be positioned over 1700 feet east of ATP’s flowline and 3450 feet north of Shell’s 

Europe to Mars Flowlines. Proposed Location N will not interfere with these flowlines. Currently, there are 

no other flowlines within the vicinity of Proposed Location N. 

Proposed Location O, MC 762: 

 X = 904,232 1352’ FWL 

 Y = 10,233,744 1104’ FSL 

Mississippi Canyon 762, Proposed Location O is located in a water depth of approximately 3150 feet. 

Proposed Location O is located near the center of a near-surface ancient slump valley. There is no evidence 

of seafloor or near-surface faulting, slumping, amplitude or fluid expulsion features in the vicinity of 

Proposed Location O. Proposed Location O will not disturb any high-density areas of chemosynthetic 

communities. 

Proposed Location O will be positioned 228 feet northwest of Shell’s previously drilled MC 806-3 wellsite. 

Proposed Location O will be positioned 5418 feet southwest of Shell’s previously drilled MC 762 #3 wellsite. 

Proposed Location O will be positioned 6045 feet southwest of Shell’s previously drilled MC 762 #2 wellsite. 

Proposed Location O will not interfere with these previously drilled wellsites. 

Proposed Location O will be positioned over 1700 feet east of ATP’s flowline and 3450 feet north of Shell’s 

Europe to Mars Flowlines. Proposed Location O will not interfere with these flowlines. Currently, there are 

no other flowlines within the vicinity of Proposed Location O. 

Proposed Location P, MC 762: 

 X = 904,288 1408’ FWL 

 Y = 10,233,794 1154’ FSL 

Mississippi Canyon 762, Proposed Location P is located in a water depth of approximately 3150 feet. 

Proposed Location P is located near the center of a near-surface ancient slump valley. There is no evidence of 
seafloor or near-surface faulting, slumping, amplitude or fluid expulsion features in the vicinity of Proposed 

Location P. Proposed Location P will not disturb any high-density areas of chemosynthetic communities. 

Proposed Location P will be positioned 199 feet northwest of Shell’s previously drilled MC 806-3 wellsite. 

Proposed Location P will be positioned 5864 feet southwest of Shell’s previously drilled MC 762 #3 wellsite. 

Proposed Location P will be positioned 6045 feet southwest of Shell’s previously drilled MC 762 #2 wellsite. 

Proposed Location P will not interfere with these previously drilled wellsites. 

Proposed Location P will be positioned over 1700 feet east of ATP’s flowline and 3450 feet north of Shell’s 

Europe to Mars Flowlines. Proposed Location P will not interfere with these flowlines. Currently, there are 

no other flowlines within the vicinity of Proposed Location P. 

Proposed Location Q, MC 762: 

X = 904,357 1477’ FWL 

Y = 10,233,765 1125’ FSL 

Mississippi Canyon 762, Proposed Location Q is located in a water depth of approximately 3150 feet. 

Proposed Location Q is located near the center of a near-surface ancient slump valley. There is no evidence 

of seafloor or near-surface faulting, slumping, amplitude or fluid expulsion features in the vicinity of 

Proposed Location Q. Proposed Location Q will not disturb any high-density areas of chemosynthetic 

communities. 

Proposed Location Q will be positioned 159 feet west of Shell’s previously drilled MC 806-3 wellsite. 

Proposed Location Q will be positioned 5825 feet southwest of Shell’s previously drilled MC 762 #3 wellsite. 

Proposed Location Q will be positioned 5957 feet southwest of Shell’s previously drilled MC 762 #2 wellsite. 

Proposed Location Q will not interfere with these previously drilled wellsites. 

Proposed Location Q will be positioned over 1700 feet east of ATP’s flowline and 3450 feet north of Shell’s 

Europe to Mars Flowlines. Proposed Location Q will not interfere with these flowlines. Currently, there are 

no other flowlines within the vicinity of Proposed Location Q. 

Proposed Location R, MC 762: 

 X = 904,337 1457’ FWL 

 Y = 10,233,589 949’ FSL 

Mississippi Canyon 762, Proposed Location R is located in a water depth of approximately 3150 feet. 

Proposed Location R is located near the center of a near-surface ancient slump valley. There is no seafloor 

faulting in the vicinity of Proposed Location R. 

Mississippi Canyon 762, Proposed Location R is located in a water depth of approximately 3152 feet. 

Proposed Location R is located near the center of a near-surface ancient slump valley. There is no evidence 

of seafloor or near-surface faulting, slumping, amplitude or fluid expulsion features in the vicinity of 

Proposed Location R. Proposed Location R will not disturb any high-density areas of chemosynthetic 

communities. 

Proposed Location R will be positioned 40 feet west of Shell’s previously drilled MC 806-3 wellsite. 

Proposed Location R will be positioned 5835 feet southwest of Shell’s previously drilled MC 762 #3 wellsite. 

Proposed Location R will be positioned 5967 feet southwest of Shell’s previously drilled MC 762 #2 wellsite. 

Proposed Location R will not interfere with these previously drilled wellsites. 

Proposed Location R will be positioned over 1700 feet east of ATP’s flowline and 3450 feet north of Shell’s 

Europe to Mars Flowlines. Proposed Location R will not interfere with these flowlines. Currently, there are 

no other flowlines within the vicinity of Proposed Location R. 
Proposed Surface Locations S, MC 762: 

 X = 904,372 1492’ FWL 

 Y = 10,233,584 944’ FSL 

Mississippi Canyon 762, Proposed Location S is located in a water depth of approximately 3150 feet. 

Proposed Location S is located near the center of a near-surface ancient slump valley. There is no evidence of 

seafloor or near-surface faulting, slumping, amplitude or fluid expulsion features in the vicinity of Proposed 

Location S. Proposed Location S will not disturb any high-density areas of chemosynthetic communities. 

Proposed Surface Location S will be positioned 54 feet southwest of Shell’s previously drilled MC 806-3 

wellsite. Proposed Location S will be positioned 5881 feet southwest of Shell’s previously drilled MC 762 

#3 wellsite. Proposed Location S will be positioned 6012 feet southwest of Shell’s previously drilled MC 762 

#2 wellsite. Proposed Location S will not interfere with these previously drilled wellsites. 

Proposed Location S will be positioned over 1700 feet east of ATP’s flowline and 3450 feet north of Shell’s 

Europe to Mars Flowlines. Proposed Location S will not interfere with these flowlines. Currently, there are 

no other flowlines within the vicinity of Proposed Location S. 

Proposed Surface Locations T, MC 762: 

 X = 904,262 1382’ FWL 

 Y = 10,233,530 890’ FSL 

Mississippi Canyon 762, Proposed Location T is located in a water depth of approximately 3150 feet. 

Proposed Location T is located near the center of a near-surface ancient slump valley. There is no evidence 

of seafloor or near-surface faulting, slumping, amplitude or fluid expulsion features in the vicinity of 

Proposed Location T. Proposed Location T will not disturb any high-density areas of chemosynthetic 

communities. 

Proposed Location T will be positioned 170 feet southwest of Shell’s previously drilled MC 806-3 wellsite. 

Proposed Location T will be positioned 6003 feet southwest of Shell’s previously drilled MC 762 #3 wellsite. 

Proposed Location T will be positioned 6135 feet southwest of Shell’s previously drilled MC 762 #2 wellsite. 

Proposed Location T will not interfere with these previously drilled wellsites. 

Proposed Location T will be positioned over 1700 feet east of ATP’s flowline and 3450 feet north of Shell’s 

Europe to Mars Flowlines. Proposed Location T will not interfere with these flowlines. Currently, there are 

no other flowlines within the vicinity of Proposed Location T. 

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

Surface Renderings (ESR’s), ESR’s with amplitudes applied, and AUV high-resolution data, Mississippi 

Canyon 762, Proposed Locations M, N, O, P, Q, R, S and T appear suitable for the planned activity. 

Dougal Grant Arlette C. Nunez 

Staff Geologist Shallow Hazard Interpreter 

6(b) – 6(f)

Pursuant to NTL No. 20 08-G04 the p roposed operations covered by this EP do not inv olve operations 

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

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

 
G. ROV Monitoring Plan

In accordance with the provisions of NTL No. 2008-G06, Remotely Operated Vehicle Surveys in Deepwater, 

Mississippi Canyon Block 762 located in Grid 12, which is an area that has adequate ROV survey coverage. 

Therefore we are not proposing to run the pre and post ROV survey in accordance with the NTL. 

H. Threatened and Endanger Species Information

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

these species has been designated in the Gulf of Mexico. 

Common Name Scientific Name T/E Status 

Hawksbill Turtle Eretmochelys imbricata E 

Green Turtle Chelonia mydas T 

Kemp's Ridley Turtle Lepidochelys kempii E 

Leatherback Turtle Dermochelys coriacea E 

Loggerhead Turtle Caretta caretta T 

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

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

these species has been designated in the Gulf of Mexico. 

Common Name Scientific Name T/E Status 

Atlantic Spotted Dolphin Stenella frontalis 

Blainville's Beaked Whale Mesoplodon densirostris 

Blue Whale Balaenoptera musculus E 

Bottlenose Dolphin Tursiops truncatus 

Bryde's Whale Balaenoptera edeni 

Clymene Dolphin Stenella clymene 

Cuvier's Beaked Whale Ziphius cavirostris 

Dwarf Sperm Whale Kogia simus 

False Killer Whale Pseudorca crassidens 

Fin Whale Balaenoptera physalus E 

Fraser's Dolphin Lagenodelphis hosei 

Gervais' Beaked Whale Mesoplodon europaeus 

Humpback Whale Megaptera novaeangliae E 

Killer Whale Orcinus orca 

Melon-headed Whale Peponocephala electra 

Minke Whale Balaenoptera acutorostrata

Northern Right Whale Eubalaena glacialis 

Pantropical Spotted Dolphin Stenella attenuata 

Pygmy Killer Whale Feresa attenuata 

Pygmy Sperm Whale Kogia breviceps 

Risso's Dolphin Grampus griseus 

Rough-toothed Dolphin Steno bredanensis 

Sei Whale Balaenoptera borealis E 

Short-finned Pilot Whale Globicephala macrorhynchus

Sowerby's Beaked Whale Mesoplodon bidens 

Sperm Whale Physeter macrocephalus E 

Spinner Dolphin (Long-snouted) Stenella longirostris 

Striped Dolphin Stenella coeruleoalba 
I. Archaeological Report

An Archeological Report for MC 762 & 806 was prepared by Fugro Geoservices, Inc for Shell and submitted to 

the BOEMRE on April 25, 2006. Also submitted was an additional Archeological Assessment prepared by C&C 

Technologies for MC 762 & vicinity dated October 8, 2008 covering additional area. 

All of the unidentified sonar contacts within 2000’ of the proposed surface location are interpreted as modern 

debris associated primarily with industrial waste dumping or lease development activities. These sonar 

contact are not recommended for archeological avoidance or investigation. 

J. Air and Water Quality Information

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

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

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

K. Socioeconomic Information

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

additional information relating to air and water q uality information. For specific information relating to 

socioeconomic information please refer to the EIA, Attachment 18. 
SECTION 7: Waste and Discharge Information

A. Projected Generated Wastes
B. Wastes to transport/dispose of onshore

C. Modeling Report

Shell did not model the trajectory for discharges because it is not required in the GOM.
SECTION 8: AIR EMISSIONS INFORMATION

A. Emissions Worksheet and Screening Questions 

Screening Questions for EP’s Yes No 

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

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

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

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

x 

Do your emission calculations include any emission reduction measures or 

modified emission factors?

X 

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

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

(ppm)? X 

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

From any proposed well? X 

Do you propose to burn produced hydrocarbon liquids? X 

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

provide: 

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

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

worksheets. You can submit either these summary forms or use the format below. You do not need to 

include the entire set of worksheets. 

Air Pollutant Plan 

Emission1 

Amounts 

(tons) 

Calculated 

Exemption2

Amounts 

(tons) 

Calculated 

Complex Total 

Emission 

Amounts3

(tons) 

Carbon monoxide CO 

Particulate matter (PM) NA 

Sulphur dioxide (SO2) 

Nitrogen oxides (NOx) 

Volatile organic compounds (VOC) 

1

 For activities proposed in your EP or DOCD, list the projected emissions calculated from the worksheets. 2

 List the exemption amounts for your proposed activities calculated by using the formulas in 30 CFR 250.303(d). 3

 List the complex total emissions associated with your proposed activities calculated from the worksheets 

(2) Contact: Sylvia Bellone, (504) 728-7215, Sylvia.Bellone@shell.com

C. Worksheets

 See Attached worksheets. 
COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore Inc MC 762 OCS-G 7957 W. Boreas Subsea M, N, O, P, Q, R, S, T

Emitted Substance

Year TPY

 PM SOx NOx VOC CO

2011 39.35 22.24 1335.79 40.66 291.432012 9.58 5.44 326.73 9.89 71.28

Allowable 1698.30 1698.30 1698.30 1698.30 46758.33
COMPANY Shell Offshore Inc

AREA MC BLOCK 762LEASE OCS-G 7957PLATFORM W. Boreas SubseaWELL M, N, O, P, Q, R, S, TCOMPANY CONTACT Sylvia Bellone

TELEPHONE NO. 5047287215REMARKS NJD RigLEASE TERM PIPELINE CONSTRUCTION INFORMATION:

YEAR NUMBER OF TOTAL NUMBER OF CONSTRUCTION DAYS

PIPELINES

20102011201220132014201520162017201820192020
Fuel Usage Conversion Factors Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine R

SCF/hp-hr 9.524 SCF/hp-hr 7.143 GAL/hp-hr 0.0483 AP4

Equipment/Emission Factors units PM SOx NOx VOC CO RNG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP4NG 4-cycle lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP4NG 4-cycle rich gms/hp-hr 0.00185 10 0.14 8.6 AP4

Diesel Recip. < 600 hp. gms/hp-hr 1 0.1835 14 1.12 3.03 AP4

Diesel Recip. > 600 hp. gms/hp-hr 0.32 0.1835 11 0.33 2.4 AP4Diesel Boiler lbs/bbl 0.084 0.3025 0.84 0.008 0.21 AP42 NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 AP42 1.4-1NG Flares lbs/mmscf 0.593 71.4 60.3 388.5 AP42 Liquid Flaring lbs/bbl 0.42 6.83 2 0.01 0.21 AP42 1.Tank Vapors lbs/bbl 0.03 E&P Fugitives lbs/hr/comp. 0.0005 APGlycol Dehydrator Vent lbs/mmscf 6.6 LaGas Venting lbs/scf 0.0034

Sulfur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.05 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

Diesel fuel intended for locomotive, marine and non-road engines and equipment is requirDiesel fuel maximum specification of 500 ppm sulfur in 2007, per EPA regulation. Diesel fuavailable. http://www.clean-diesel.org/nonroad.html
Basis for various estimates Used in this A

Schedule, per Rob Sloan, 

Stephen Castle, Hal Edwards 

meeting with RBK 4/6/11

batch set wells 2011 6

MC805 one well deppening 1

Event Comments Start Stop Duration 2011 Duration 2012 Yearly 

Duration 

2013-2018

NJD Batch Set Note 1 7/1/11 9/29/11 90 0 0

NJD MC 805 One Well 

deepening 2011

Note 1 9/29/2011 12/31/2011 93 0 0

NJD MC 805 One Well 

deepening, cont, 2012

Note 1 1/1/2012 2/27/2012 0 57 0

Note 1 Noble Jim Day:  Total Duration is 8 months: July 1, 2011 to End Feb. 2012

1. Begins drilling the

batchset on July 1, 2011

2. Batchset includes six

wells for a total duration of 90

3. The two additional

wells that are being permited

will not be included in the

batchset.  They’re

contingency wells and they

will be included in the Bully 1

schedule at the end of the

4. The MC ‐805 well

duration will be 150 days

5. The NJD will stay on

West Boreas until the end of

February (1 month past the

contracted time, however

contract allows for

completion of an operation,

so if we’re behind schedule

Many cells are linked or are used as links in other sheets- change cell contents OR add/delete 

rows/columns with caution!

31A5835E.msg
Noble Jim Day main Engine Operating scenarios (Modes)

per embedded email

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% 

Scenario 4 – Drilling ahead with BOP deployed 

 Four Engines online @ 40 to 50% 

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

1 45 40 65 50

2 45 40 65 50

3 45 40 65 50

4 45 40 65 50

5 00 0 0

6 00 0 0

7 00 0 0

8 00 0 0

Frequency of scenario 

occurrence in Campaign, % 0 0 10 90

Individual Eng HP, nameplate 6786 6786 6786 6786

Total HP delivered from all 8 

engines in Campaign, by

0 0 1764.36 12214.8

Average % Load delivered from 

each engine in Campaign 0.0% 0.0% 3.3% 22.5%

25.8%

% Load

Given Mode 3 and 4 are highest load modes, assume rig operates in mode 3 (transit) 

10% of time and remainder in Mode 4 (90% of time as a conservative estimate for 

For simplification, the above average % loads are added to arrive at a single Overall Operating Mode 

Engine loads will 

vary from above: 

the % shown is 

the AVERAGE 

thru-out the 

campaign for 

each engine and 

is used to 

estimate 

ANNUAL 

emissions

Fw EPA info.msg
NJD Support Vessels

per Discussion with Brad Landreth, Sr Stf Logistics Specialist 4/4/11

6 batch set wells: 15 days/well

1 well deepening: 112 days

Event Vessel HP umber of Vesse %Load hr/d Days/Event Comments

6 Well batch set 370' OSV 12000 1 50% 24 90

Shell policy restricts D/P to < 50% 

near rig. When in standby away 

from rig but within 25 miles load wil 

be < 50% (conserve fuel). When 

transiting into/out of 25 miles, 

vessels can be restricted to <50% 

load

6 Well batch set 280' OSV 9440 1 50% 24 90

On average two vessels withn 25 

miles at any give time. Shell policy 

restricts D/P to < 50% near rig. 

When in standby away from rig but 

within 25 miles load wil be < 50% 

(conserve fuel). When transiting 

into/out of 25 miles, vessels can be 

restricted to <50% load

6 Well batch set 280' OSV 9440 1 50% 24 90

On average two vessels withn 25 

miles at any give time. Shell policy 

restricts D/P to < 50% near rig. 

When in standby away from rig but 

within 25 miles load wil be < 50% 

(conserve fuel). When transiting 

into/out of 25 miles, vessels can be 

restricted to <50% load

6 Well batch set Crew Boat 5400 1 50% 8 90

On average crew vessels will be 

within 25 miles 30% of time. To 

model this set hr/d=8. Shell policy 

restricts D/P to < 50% near rig. 

When in standby away from rig but 

within 25 miles load wil be < 50% 

(conserve fuel). When transiting 

into/out of 25 miles, vessels can be 

restricted to <50% load

Well deepening 280' OSV 9440 1 50% 24 150

On average one vessel withn 25 

miles at any give time. Shell policy 

restricts D/P to < 50% near rig. 

When in standby away from rig but 

within 25 miles load wil be < 50% 

(conserve fuel). When transiting 

into/out of 25 miles, vessels can be 

restricted to <50% load

Well deepening Crew Boat 5400 1 50% 8 150

On average crew vessels will be 

within 25 miles 30% of time. To 

model this set hr/d=8. Shell policy 

restricts D/P to < 50% near rig. 

When in standby away from rig but 

within 25 miles load wil be < 50% 

(conserve fuel). When transiting 

into/out of 25 miles, vessels can be 

restricted to <50% load
Miscellaneous basis

NJD Sources

- 8 main engines rated at 6786 HP (nameplate)

- One emergency generator at 2550 HP (nameplate). Operated for 1 hr/week for testing

- One wireline unit may be used at 300 HP or less. Usage is planned for 15 days per well

- All other equipment is electric (e.g cement units, logging units, cranes) or negligable in emissions potential (e.g. life boats)

Above info for NJD per Hal Edwards, Team Lead

4/7/11- all Basis information was validated by Hal Edwards, Well Delivery Gulf Of Mexico-Team Lead in emails to Rob Kuehn 4/7/11
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc MC 762 OCS-G 7957 W. Boreas Subse M, N, O, P, Q, R, S, T Sylvia Bellone 5047287215 NJD Rig

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

Diesel Engines HP GAL/HR % Average Eng Load GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLINGNoble Jim DayAll Modes PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 183 4.78 2.74 164.42 4.93 35.87 2.70 

PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 183 4.78 2.74 164.42 4.93 35.87 2.70 PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 183 4.78 2.74 164.42 4.93 35.87 2.70 PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 183 4.78 2.74 164.42 4.93 35.87 2.70 PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 183 4.78 2.74 164.42 4.93 35.87 2.70 PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 183 4.78 2.74 164.42 4.93 35.87 2.70 PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 183 4.78 2.74 164.42 4.93 35.87 2.70 PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 183 4.78 2.74 164.42 4.93 35.87 2.70 Energency Generator>600hp diesel 2550 123.165 2955.96 1 26 1.80 1.03 61.78 1.85 13.48 0.02 AUXILIARY EQUIP<600hp (wireline unit) 300 14.49 347.76 24 105 0.66 0.12 9.25 0.74 2.00 0.83 All other equipment is electric (e.g cranes) or negligable in emissions potential (e.g. life boats)370' OSV 12000 579.6 50% 6955.20 24 90 8.46 4.85 290.75 8.72 63.44 4.57 280' OSV 9440 455.952 50% 5471.42 24 90 6.65 3.82 228.72 6.86 49.90 3.59 280' OSV 9440 455.952 50% 5471.42 24 90 6.65 3.82 228.72 6.86 49.90 3.59 Crew Boat 5400 260.82 50% 3129.84 8 90 3.81 2.18 130.84 3.93 28.55 0.69 280' OSV 9440 455.952 50% 5471.42 24 93 6.65 3.82 228.72 6.86 49.90 3.71 Crew Boat 5400 260.82 50% 3129.84 8 93 3.81 2.18 130.84 3.93 28.55 0.71 

2011 YEAR TOTAL 76.75 43.76 2624.97 79.21 572.71 39.35 

EXEMPTION 

CALCULATION DISTANCE FROM LAND IN MILES 1698.30 

51.0

Batch Set Support VesselsWell deepening Support Vessels

See Sheet "Basis for 

estimates"

Engine loads will 

vary from below- the 

% shown are 

AVERAGES thru-out 

the campaign
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc MC 762 OCS-G 7957 W. Boreas Subse M, N, O, P, Q, R, S, T Sylvia Bellone 5047287215 NJD Rig

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

Diesel Engines HP GAL/HR % Average Eng Load in Scenario GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

Drilling

Noble Jim DayAll Modes PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 57 4.78 2.74 164.42 4.93 35.87 0.84 

PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 57 4.78 2.74 164.42 4.93 35.87 0.84 

PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 57 4.78 2.74 164.42 4.93 35.87 0.84 

PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 57 4.78 2.74 164.42 4.93 35.87 0.84 

PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 57 4.78 2.74 164.42 4.93 35.87 0.84 

PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 57 4.78 2.74 164.42 4.93 35.87 0.84 

PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 57 4.78 2.74 164.42 4.93 35.87 0.84 

PRIME MOVER>600hp diesel 6786 327.7638 25.8% 2025.58 24 57 4.78 2.74 164.42 4.93 35.87 0.84 

Energency Generator>600hp diesel 2550 123.165 2955.96 1 8 1.80 1.03 61.78 1.85 13.48 0.01 

AUXILIARY EQUIP<600hp (wireline unit) 300 14.49 347.76 24 15 0.66 0.12 9.25 0.74 2.00 0.12 All other equipment is electric (e.g cranes) or negligable in emissions potential (e.g. life boats)280' OSV 9440 455.952 50% 5471.42 24 57 6.65 3.82 228.72 6.86 49.90 2.28 

Crew Boat 5400 260.82 50% 3129.84 8 57 3.81 2.18 130.84 3.93 28.55 0.43 

2012 YEAR TOTAL 51.18 29.09 1745.94 52.84 380.92 9.58 

EXEMPTION CALCULATION DISTANCE FROM LAND IN MILES 1698.30 

51.0

many cells are linked or are used as links in other sheets- change with caution!NJD Support vessels

See Sheet "Basis for 

estimates"

Engine loads will 

vary from belowthe % shown are AVERAGES thruout the campaign
Proposed Limits for EP

Proposed Limit Infor

Source Year Total Fuel Consumed in the Year, 

gal

Comment Proposed Compliance 

Assurance method

Equivale

fuel rates 

comb

Equal to sum of Daily Consumption in 

Column F of Emissions spreadsheets times 

total days of drilling in the year

Equal 

Consumpt

Emissio

NJD Main 

Engines

2011 2,965,450 Limiting total fuel consumed in the period ensures 

average annual emissions as estimated won't be exceeded (while still allowing for short periods of time where fuel usage may be higher than the daily fuel usage from Column F might be exceeded due to currents, drilling conditions, etc)

Maintain logs of fuel consumed by all main engines, and rig location. Retain records through duration of EP for inspection if requested by BOEM.

NJD Main 

Engines

2012 923,665 Limiting total fuel consumed in the period ensures 

average annual emissions as estimated won't be exceeded (while still allowing for short periods of time where fuel usage may be higher than the daily fuel usage from Column F might be exceeded due to currents, drilling conditions, etc)

Maintain logs of fuel consumed by all main engines, and rig location. Retain records through duration of EP for inspection if requested by BOEM.

Source Year Proposed Limit Comment Proposed Compliance 

Assurance method

Support 

vessels

All years All vessels will maintain total engine 

HP less than or equal to 50% design load while within 25 nm of rig.

Since emission estimates assume all vessels are at or below 50% through-out the campaign, limiting loads to 50% or less will ensure average annual emissions are not exceeded in any given year.

Maintain logs of all vessel loads and locations. Retain records through duration of EP for inspection if requested by BOEM
COMPANY Shell Offshore Inc

AREA MC BLOCK 762LEASE OCS-G 7957PLATFORM W. Boreas SubseaWELL M, N, O, P, Q, R, S, TCOMPANY CONTACT Sylvia Bellone

TELEPHONE NO. 5047287215REMARKS Bully RigLEASE TERM PIPELINE CONSTRUCTION INFORMATION:

YEAR NUMBER OF TOTAL NUMBER OF CONSTRUCTION DAYS

PIPELINES

20102011201220132014201520162017201820192020
COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore Inc MC 762 OCS-G 7957 W. Boreas Subsea M, N, O, P, Q, R, S, T

Emitted Substance

Year TPY

 PM SOx NOx VOC CO

2012 15.06 8.63 343.85 15.53 112.922013 64.67 37.08 1526.19 66.69 485.002014 64.67 37.08 1526.19 66.69 485.002015 64.67 37.08 1526.19 66.69 485.002016 64.67 37.08 1526.19 66.69 485.002017 64.67 37.08 1526.19 66.69 485.002018 64.67 37.08 1526.19 66.69 485.00

Allowable 1698.30 1698.30 1698.30 1698.30 46758.33
Fuel Usage Conversion Factors Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine RE

SCF/hp-hr 9.524 SCF/hp-hr 7.143 GAL/hp-hr 0.0483 AP42 

Equipment/Emission Factors units PM SOx NOx VOC CO RENG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3.2NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP42 NG 4-cycle lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP42 NG 4-cycle rich gms/hp-hr 0.00185 10 0.14 8.6 AP42 

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

Diesel Recip. > 600 hp. gms/hp-hr 0.32 0.1835 11 0.33 2.4 AP42 3.4-1 anDiesel Boiler lbs/bbl 0.084 0.3025 0.84 0.008 0.21 AP42 1NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 AP42 1.4-1, NG Flares lbs/mmscf 0.593 71.4 60.3 388.5 AP42 Liquid Flaring lbs/bbl 0.42 6.83 2 0.01 0.21 AP42 1.3Tank Vapors lbs/bbl 0.03 E&P FFugitives lbs/hr/comp. 0.0005 API SGlycol Dehydrator Vent lbs/mmscf 6.6 La. Gas Venting lbs/scf 0.0034

Sulfur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.05 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

Note 1: Bully main engines are certified by IMO and EPA as Tier 2 7.8 gm/kw-hr1 = 5

1 See embedded certification sheets and nameplate picture.

The Bully main engines Tier 2 limit are calculated as follows:

Bore, mm Stroke, mm Vol, mm3 Vol, Dm3 Vol, in3

230.19 279.4 11627603.2 11.63 710

Per Table 7 of EPA (EPA420-F-04-031 August 2004, see http://www.epa.gov/nonroad/marine/420f04031.pdf ), based on dm3 peappropriate Tier 2 limit is 7.8 gm/kw-hr

per cylinder

Diesel fuel intended for locomotive, marine and non-road engines and equipment is required 

2 Based on AP-42 Miscellaneous data and conversion factors available at http://www.epa.gov/ttn/chief/ap42/appendix/appa.p

1 kw-hr equal to 1.341 hp-hr.

\\houicvfc006\

rt.Kuehn$\Cached\M

\\houicvfc006\

rt.Kuehn$\Cached\M

6BA026B5.JPG
Basis for various estimates Used in this AQR

Schedule, per Rob Sloan, Stephen Castle, Hal 

Edwards meeting with RBK 4/6/11

batch set wells 2011 6MC805 one well deppening 2012 1Drill and Complete Wells 6Event Comments Start Stop Duration 2011 Duration 2012 Yearly 

Duration 2013-

2018

Bully Drill and Complete Note 2 10/1/2012 12/31/2012 0 91 0Bully Drill and Complete Note 2 1/1/2013 12/31/2016 0 0 365Two Years Contingency with Bully In case two added wells are needed to 1/1/2017 12/31/2018 365Note 1 Reserved

Note 2 Noble Bully 1: Total Duration is 4 years: Oct, 2012 to Oct. 2016.

1. Begins drilling on Oct. 2012

2. The schedule is for a Drill/Complete/Drill/Complete sequence

3. Continuous operations for 4 years

4. Drill: 120 days/Complete: 60 days equals 2 wells per 360 day period.

Many cells are linked or are used as links in other sheets- change cell contents OR add/delete rows/columns with caution!

31A5835E.msg
per embedded email

- Scenario 1 Drilling without active heave or with light load active heave (4 engines @ 45%) 75% of the time- Scenario 2 Heavy string weight with active heave (6 engines @ 40 – 60%) 20% of the time- Scenario 3 Transit (4 engines @ 60%) 5% of the timeThis can be converted to an equivalent TOTAL ENGINE LOAD for purposes of emissions estimating purposes, as follows:

Engine Op Mode 1 Op Mode 2 Op Mode 3

1 45 60 602 45 60 603 45 60 604 45 60 605 0 60 06 0 60 07 00 08 00 0

Frequency of scenario occurrence in C 50 40 10

Individual Eng HP, nameplate 5400 5400 5400Total HP delivered from all 8 engines in Campaign, by scenario

4860 7776 1296

Average % Load delivered from each 11.3% 18.0% 3.0%

32.3%

% Load

Bully Main Engine operating scenarios (Modes)

As a conservative estimate for emissions, given Mode 2 and 3are highest load modes, assume rig operates in mode 2 and 3 at twice the frequency propose by Noble. The balance (50%) is allocated to mode 1.

For simplification, the above average % loads are added to arrive at a single Overall Operating Mode 

Engine loads 

will vary from 

above: the % 

shown is the 

AVERAGE 

thru-out the 

campaign for 

each engine 

and is used to 

estimate 

ANNUAL 

emissions

95937B97.msg
Bully Support Vessels (yearly)

per email fom Brad Landreth, Sr Stf Logistics Specialist 4/6/11Event Vessel HP umber of Vesse %Load hr/d Days/Event Events/year Comments

Normal Support thru-out 2012 280' OSV 9440 1 50% 24 91

On average one vessel wittime. Shell policy restricts DWhen in standby away from load wil be < 50% (conservinto/out of 25 miles, vessel<50% load

Normal Support thru-out 2012 Crew Boat 5400 1 50% 8 91

On average crew vessels w30% of time. To model this restricts D/P to < 50% near away from rig but within 25 (conserve fuel). When tranmiles, vessels can be restr

Normal Support thru-out each year 2013-2018 280' OSV 9440 1 50% 24 365

On average one vessel wittime. 

Normal Support thru-out each year 2013-2018 Crew Boat 5400 1 50% 8 365

On average crew vessels w30% of time. To model this restricts D/P to < 50% near away from rig but within 25 (conserve fuel). When tranmiles, vessels can be restr

Swap from Drill to complete 280' OSV 9440 1 50% 24 10 2

Swap from Drill to complete 280' OSV 9440 1 50% 24 10 2

ROV Assist Vessel durng completion 348' AHTS - Laney 39900 1 50% 24 7 2Frac Boat during completion 240' - Stim Star 5400 1 50% 24 7 2

Two drill-complete cycles ptherefore set at two Events restricts D/P to < 50% near away from rig but within 25 

DE2B3D1D.msg
Miscellaneous basis

Bully Sources

- 8 main engines rated at 5400 HP (nameplate)- One emergency generator at 2150 HP (nameplate). Operated for 3 hr/month for testing- All other equipment is electric (e.g cement units, logging units, cranes) or negligable in emissions potential (e.g. life boats)

Above info for Bully from Shell April 2010 PSD and Title V Permit Application to USEPA Region 4

4/7/11- all Basis information was validated by Hal Edwards, Well Delivery Gulf Of Mexico-Team Lead in emails to Rob Kuehn 4/7/11
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc MC 762 OCS-G 7957 W. Boreas Subse M, N, O, P, Q, R, S, T Sylvia Bellone 5047287215 Bully Rig

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

Diesel Engines HP GAL/HR % Average Eng Load in Scenario GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLINGBully 1 All Operating Modes 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 91 3.81 2.18 69.18 3.93 28.55 1.34 

20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 91 3.81 2.18 69.18 3.93 28.55 1.34 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 91 3.81 2.18 69.18 3.93 28.55 1.34 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 91 3.81 2.18 69.18 3.93 28.55 1.34 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 91 3.81 2.18 69.18 3.93 28.55 1.34 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 91 3.81 2.18 69.18 3.93 28.55 1.34 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 91 3.81 2.18 69.18 3.93 28.55 1.34 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 91 3.81 2.18 69.18 3.93 28.55 1.34 8-710-GC Emerg Gen 2150 103.845 2492.28 3 3 1.52 0.87 52.09 1.56 11.37 0.01 All other equipment is electric (e.g cranes) or negligable in emissions potential (e.g. life boats)

Bully Support vessels 280' OSV 9440 455.952 50% 5471.42 24 91 6.65 3.82 228.72 6.86 49.90 3.63 

Crew Boat 5400 260.82 50% 3129.84 8 91 3.81 2.18 130.84 3.93 28.55 0.69 

2012 YEAR TOTAL 42.42 24.33 965.12 43.75 318.19 15.06 

EXEMPTION CALCULATION DISTANCE FROM LAND IN MILES 1698.3

51.0

many cells are linked or are used as links in other sheets- change with caution

See Sheet "Basis for 

estimates"

Engine loads will 

vary from belowthe % shown are 

AVERAGES thruout the campaign
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc MC 762 OCS-G 7957 W. Boreas Subsea M, N, O, P, Q, R, S, T Sylvia Bellone 5047287215 #REF!

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

Diesel Engines HP GAL/HR % Average Eng Load in Scenario GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

DRILLING Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

Bully 1 All Operating Modes 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 365 3.81 2.18 69.18 3.93 28.55 5.38 

20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 365 3.81 2.18 69.18 3.93 28.55 5.38 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 365 3.81 2.18 69.18 3.93 28.55 5.38 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 365 3.81 2.18 69.18 3.93 28.55 5.38 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 365 3.81 2.18 69.18 3.93 28.55 5.38 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 365 3.81 2.18 69.18 3.93 28.55 5.38 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 365 3.81 2.18 69.18 3.93 28.55 5.38 20-710-GC Prime Mover 5400 260.82 32.25% 2018.75 24 365 3.81 2.18 69.18 3.93 28.55 5.38 8-710-GC Emerg Gen 2000 96.6 n/a 2318.40 3 12 1.41 0.81 48.46 1.45 10.57 0.03 All other equipment is electric (e.g cranes) or negligable in emissions potential (e.g. life boats)280' OSV 9440 455.952 50% 5471.42 24 365 6.65 3.82 228.72 6.86 49.90 14.57 Crew Boat 5400 260.82 50% 3129.84 8 365 3.81 2.18 130.84 3.93 28.55 2.78 280' OSV 9440 455.952 50% 5471.42 24 20 6.65 3.82 228.72 6.86 49.90 0.80 280' OSV 9440 455.952 50% 5471.42 24 20 6.65 3.82 228.72 6.86 49.90 0.80 348' AHTS - Laney 39900 1927.17 50% 23126.04 24 14 28.12 16.13 966.74 29.00 210.93 2.36 240' - Stim Star 5400 260.82 50% 3129.84 24 14 3.81 2.18 130.84 3.93 28.55 0.32 

2013-2018 YEAR TOTAL 87.56 50.21 2516.51 90.29 656.67 64.67 

EXEMPTION CALCULATION DISTANCE FROM LAND IN MILES 1698.30 

51.0

many cells are linked or are used as links in other sheets- change with caution!Bully Support vessels

See Sheet "Basis 

for estimates"

Engine loads will 

vary from belowthe % shown are 

AVERAGES thruout the campaign
Proposed Limits for EP

Proposed Limit Inform

Source Year Total Fuel Consumed in the Year, 

gal

Comment Proposed Compliance 

Assurance method

Equivalen

fuel rates 

combi

Equal to sum of Daily Consumption in 

Column F of Emissions spreadsheets 

times total days of drilling in the year

Equal t

Consumpti

Emission

Bully Main 

Engines

2012 1,469,648 Limiting total fuel consumed in the period ensures 

average annual emissions as estimated won't be exceeded (while still allowing for short periods of time where fuel usage may be higher than the daily fuel usage from Column F might be exceeded due to currents, drilling conditions, etc)

Maintain logs of fuel consumed by all main engines, and rig location. Retain records through duration of EP for inspection if requested by BOEM.

Bully Main 

Engines

Each year 2013-

2018

5,894,741 Limiting total fuel consumed in the period ensures 

average annual emissions as estimated won't be exceeded (while still allowing for short periods of time where fuel usage may be higher than the daily fuel usage from Column F might be exceeded due to currents, drilling conditions, etc)

Maintain logs of fuel consumed by all main engines, and rig location. Retain records through duration of EP for inspection if requested by BOEM.

Source Year Proposed Limit Comment Proposed Compliance 

Assurance method

Support 

vessels

All years All vessels will maintain total engine 

HP less than or equal to 50% design load while within 25 nm of rig.

Since emission estimates assume all vessels are at or below 50% through-out the campaign, limiting loads to 50% or less will ensure average annual emissions are not exceeded in any given year.

Maintain logs of all vessel loads and locations. Retain records through duration of EP for inspection if requested by BOEM

Bully Main Engines Tier 2 certification assurance proposal

Emissions for the Bully main engines were based on vendor certified compliance with Tier 2 standards. Compliance with the Tier 2 emission standards will be assured via normal operation and maintenance practices as decscribed in the attached document. These practices will ensure optimal performance of the engines at the Tier 2 level. Note these practices have been provisionally accepted by US EPA for the Bully rig during permitting of emissions in the eastern Gulf (east of 87.5 degrees longitude). A full description of these practices is embedded here:

\\

Americas.shell.com\
Maintenance Practices to Ensure Continued Performance at EPA Tier 2 marine Engine 

Emissions Levels for the Noble Bully Electro-Motive Diesel (EMD) Main Engines 

The eight Electro-Motive Diesel (EMD) main engines on the Noble Bully 1 rig are Tier 2 

compliant technology including intake air cooling (IAC), ignition timing retard (ITR), and high 

injection pressure (HIP). The applicable 40 CFR Part 94 Tier 2 NOX emission level for the Noble 

Bully main engines is 7.8 g/kW-hr. In addition, refined engine control software and operating 

parameters are used to control the air-to-fuel ratio by turbocharger with matching electronic 

injection control that maximizes fuel economy and engine power while minimizing emissions. 

This enhancement should result in emissions even lower than Tier 2 levels of Nox. Shell 

contends this is already an improvement over standard industry work practices. 

Furthermore, the main engines are managed by a power management system whereby a 

certain number of engines are loaded to a specified load range while other engines are 

maintained in standby mode. The Noble Bully does not require the simultaneous operation of 

all eight engines, as represented by Shell’s estimated emissions in the AQR bases for these 

engines. 

The main generator engines are normally operated such that the total load required from the 

engines is distributed across various combinations of all eight engines on a defined schedule 

throughout the drilling campaign in order to promote engine efficiency, reliability, and to 

accommodate required maintenance. 

Noble Corporation, the owner of the Noble Bully drilling vessel, utilizes a rigorous maintenance 

program recommended by EMD for the maintenance of the main engines. Maintenance 

requirements include following the specified maintenance intervals, checks, inspections, 

component change-outs, and recommended fluids and lubricants as prescribed by the 

manufacturer. Specifications for fuel oil, lubricating oils, filters, and engine coolants are 

established, and periodic sampling and analysis is conducted to ensure the specifications are 

consistently met. The detailed maintenance program and overhaul schedule for the EMD main 

engines is provided in Attachment 1. 

 

In summary, Shell proposes that adherence to these practices (enhanced computer 

controls and maintenance standards) will ensure the NOX emission levels will be 

maintained below the required Tier 2 levels used in the estimate of emissions for this 

Exploration Plan. 
Attachment 1 

EMD Scheduled Maintenance Program













SECTION 9: OIL SPILL INFORMATION

A. Oil Spill Response Planning

(i) All the proposed ac tivities and facilities in this EP will be covered by the Regi onal OSRP filed by Shell 

Offshore Inc (0689) in accordance with 30 CFR 250. An update to the Region al OSRP was filed with th e 

BOEMRE October 2010 and is pendin g approval. This plan covers Shell O ffshore Inc (SOI) (0689) 

operations in the Gulf of Mexico. AN OSRP Certification in accordance with 30 CFR 254.2 was submitted 

and accepted by the BOEMRE on December 3, 2010. 

 (ii) Spill Response Sites: 

Primary Response Equipment Locations Preplanned Staging Location(s) 

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

Fort Jackson, LA 

Fourchon, LA; Pascagoula, MS; Fort Jackson, 

LA; Venice, LA 

(iii) The names of the oil spill removal organizations (O SRO’s) under contract include Clean Gulf Associates 

(CGA), Marine Spill Response Company (MSRC), Clean Caribbean America (CCA), and OSRL/EARL. 

Worst Case Scenario Determination: 

Category Regional OSRP EP 

Type of Activity1 Drilling Rig & Subsea 

Installation 

Drilling Rig & Subsea 

Installation 

Facility Location (area/block) MC 391 MC 762 

Facility Designation2 Subsea Well C Subsea Well N 

Distance to Nearest Shoreline (miles) 72 51 

Volume3

Storage tanks (total) 

Flowlines (on facility) 

Pipelines 

Uncontrolled blowout (volume per day) 

Total Volume 

N/A 

N/A 

N/A 

405,000* BOPD 

405,000 Bbls 

N/A 

N/A 

N/A 

449,000** BOPD 

449,000 Bbls 

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

diesel) 

Crude oil Crude oil 

API Gravity(s)4 37.5o 27o 

*24 hour rate (371,000 BOPD 30 day average) 

**24 hour rate (359,000 BOPD 30 day average) although the 24 hour rate is higher than the WCD 

on file in our ROSRP, the 30 day average rate is lower. 

Footnotes: 

1. Types of activities include pipeline, platform, caisson, subsea completion or manifold, and mobile drilling rig. 

2. E.g., Well No. 2, Platform JA, Pipeline Segment No. 6373. 

3. Your regional OSRP worst-case scenario volume must be taken from the appropriate section of your regional OSRP. For 

EP’s, the worst-case scenario volume mu st be determined by using the daily worst-case discharge volume determined 

using the guidance at 30 CFR 254.47(b). For DOCD’s, the da ily worst-case discharge volume must be determined by 

using the guidance at 30 CFR 254.47 (a) and/or (b), as appropriate. 

4. Provide API gravity of all oils given under “Type of Oil(s)” above. Estimate for EP’s. 

Shell submitted the Exploration WCD scenario for MC 391 to the BOEMRE GOMR on Oc tober 26, 20 10 for 

inclusion in our Regional OSRP. 

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

regional OSRP, submitted October 26, 2010, and since the worst-case scenario determined for our EP do es 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 thre at of 

such a discharge, resulting from the activities proposed in our EP. 
B. Oil Spill Response Discussion

 1. Volume of the Worst Case Discharge 

Please refer to Section 2j of this EP. 

 2. Trajectory Analysis 

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

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

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

between the source and land segm ent contact could be im pacted. The land segm ent contact 

probabilities are shown in Table 9.C.1. 

Area/Block OCS-G Launch 

Area Land Segment Contact % 

Exploratory 

MC 762 7957 58 

Galveston, TX 1 

Jefferson, TX 1 

Cameron, LA 3 

Vermilion, LA 2 

Iberia, LA 1 

Terrebonne, LA 3 

Lafourche, LA 3 

Jefferson, LA 1 

Plaquemines, LA 8 

St. Bernard, LA 1 

Okaloosa, FL 1 

Table 9.C.1 Probability of Land Segment Impact 

 3. 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 Atm ospheric 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 oc curs nearby. Examples of at-risk resources include biological resources (such 

as birds and shellfish beds), sen sitive 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 h elp responders meet on e of the main respon se 

objectives: reducing the environmental consequences of the spill and the cleanup efforts. Additionally, 

ESI maps can be used by planners to identify vulnerable location s, 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 762 scenario. 

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

Gulf of Mexico for the Exploratory Worst Case Di scharge. The Plaquemines Parish has a total area of 

2,429 square miles of which, 845 square miles of it is land and 1,584 square miles is water. Plaquemines 

 
Parish includes two National Wildlife Refuges and one Wildlife Management Area including the Breton 

National Wildlife Refuge, the Delta National Wildlife Refuge, and the Pass a Loutre Wildlife Management 

Area. Key ESI maps for P laquemines Parish and the le gend are shown in Figures 9.C.1, 9.C.2, 9.C.3, 

9.C.4, and 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 (A CPs) were developed to provide a well coordinated 

response to oil discharges and other hazardous releases. The One Gulf Plan i s 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 protec tion of identified resources are detailed in the One Gulf Plan and 

relevant Gulf Coast ACP. 

 4. Worst Case Discharge Response 

Shell will make every effort to respond to the Mississippi Canyon 762 Worst Case Discharge as 

effectively as possible. Applied Science Associates (ASA) conducted a deepwater blowout simulation for 

The Response Group to better determine subsurface and surf ace evaporation and dispersion rates. 

Below is a table outlining the applicable evaporation and dispersion quantities: 

Mississippi Canyon 762 

Calculations 

(BBLS) 

i. 30 Day Average WCD = 359,000 bbls 

ii. Subsurface dispersion – 25% (Water Depth = ~3,100) -89,000 bbls 

iii. REMAINING WCD AFTER SUBSURFACE DISPERSION 270,000 bbls 

iv. Surface dispersion and evaporation – 25% -67,000 bbls 

TOTAL REMAINING ~203,000 bbls 

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

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

temporary storage equipment to be considered in order to cope with a WCD spill. Und er 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 applicati on (visibility & wind conditions permittin g) may be the only safe 

and viable recovery option. 

MSRC OSRV 8 foot seas 

VOSS System 4 foot seas 

Expandi Boom 6 foot seas, 20 knot winds 

Dispersants Winds more than 25 knots, 

Visibility less than 3 nautical miles, or 

Ceiling less than 1,000 feet. 

Table 9.D.2 Operational Limitations of Response Equipment 

Upon notification of the sp ill, 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 rec overy 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. 
Subsea Control and Containment: Shell, as a founding member of the MWCC, will have access to 

the IRCS that can be rapidly deployed through the MWCC. The IRCS is designed to contain oil flow in 

the unlikely event of an underwater well blowout, and is designed, constructed, tested, and available 

for rapid response. Shell’s specific containment response for GC 116 will be addressed in Shell’s NTL10 

submission at the time the APD is submitted. 

Mechanical Recovery (skimming): Response strategies include skimming utilizing available OSROs 

Oil Spill Response Vessel s (OSRVs), Oil Spill Response Barg es (OSRBs), ID Boats, and Quick Strike 

OSRVs. There is a combi ned de-rated recovery rate capability of appr oximately 606,000 barrels/day. 

Temporary storage associated with the identified skimming and temporary storage equipment equals 

approximately 762,000 barrels. 

 

De-rated Recovery Rate

(bopd) 

Storage 

(bbls) 

Offshore Recovery 516,000 540,000 

Offshore Storage 211,000 

Nearshore Recovery 90,000 11,000 

Total 606,000 762,000 

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

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

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

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

Oil Storage: The str ategy for transfer ring, 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 spill s. 

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

 Table 9.D.7 Aerial Surveillance Activation List 

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

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

first 12 hour operating day of the response. These aerial systems could disperse approximately 7,704 

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

from the Hercules C-130A within the first 12 hour operating day of the response could disperse 4,600 

to 6,100 b arrels of oil per day. F or continuing di spersant operations, the CCA’s Aerial Dispersant 

Delivery System (ADDS) would be mobilized. The A DDS has a dispersant spray capability of 5,000 

gallons per sortie. 

 Table 9.D.8 Offshore Aerial Dispersant Activation List 

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

vessel spray systems can be installed on offshore vessels of opportunity using inductor nozzles (installed 

on fire-water monitors), skid mounted systems, or purpose-built boom arm spray systems. Vessels can 

apply dispersant within the first 12-24 hours of the response and continually as directed. 

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

Subsea Dispersant: Shell has contr acted with Wild Well Co ntrol for a subsea dispersant package. 

Subsea dispersant application has been found to b e highly effective at redu cing the am ount 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.10 Subsea Dispersant Package Activation List 

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

depending on the circum stances of the release. IS B services may be provided by the pri mary OSRO 

contractors. If appropriate conditio ns exist and approvals are granted, one or multiple ISB task forces 

could be deployed offsh ore. Task forc es typically co nsist of two to four fire teams, eac h with two 

vessels capable of towing fire boom, guide boom or tow line with either a handheld or aerially-deployed 

oil ignition system. At least one support/safety boat would be present during active burning operations 

to provide logistics, safety and monitoring support. Depending upon a number of factors, up to 4 burns 

per 12-hour day could be completed per ISB fire team. Most fire boom systems can be used for 

approximately 8-12 burns before bei ng 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 migh t 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 burni ng 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 th e initial spill to 

begin ramping up fire boom production through cont racted OSRO(s). There are potential limitations 

that need to be assessed prior to ISB operations. Some limitations includ e atmospheric and sea 

conditions; oil weathering; air quality impacts; safety of response workers; and risk of secondary fires. 

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

 Shoreline Protection: If the spill went unabated, shoreline impact in Plaquemines, 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 re al time traj ectories provided by The Resp onse Group that dep ict areas of 

potential impact given actual sea and weather conditions. Strategies from the New Orleans, Louisi ana 

Area Contingency Plan, The Response Group and Unified Command would be consulted to ensure that 

environmental and special economic resources would be correctly identified and prioritized to en sure 

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

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

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

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

a more effective response to site-specific circumstances. 

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

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

available to Shell, which can be u tilized to pr otect and/or reh abilitate wildlife. The resources under 

contract for the protection and rehabilitation of affected wildlife are in Table 9.D.12. 

 
1

 

Figure 9.C.1 Environmental Sensitivity Index Map Legend 
2

Figure 9.C.2 South Pass ESI Map 
3

Figure 9.C.3 Garden Island Pass ESI Map 
4

. 

Figure 9.C.4 Pass a Loutre West ESI Map 
5

Figure 9.C.5 Main Pass ESI Map 
6

Table 9.D.4 Offshore On-Water Recovery Activation List 
7

Table 9.D.4 Offshore On-Water Recovery Activation List (continued) 
8

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

Table 9.D.4 Offshore On-Water Recovery Activation List (continued) 
10

Table 9.D.4 Offshore On-Water Recovery Activation List (continued) 
11

Table 9.D.5 Offshore On-Water Storage Activation List 
12

 Table 9.D.6 Nearshore On-Water Recovery Activation List 
13

Table 9.D.6 Nearshore On-Water Recovery Activation List (continued) 
14

Table 9.D.6 Nearshore On-Water Recovery Activation List (continued) 
15

Table 9.D.7 Aerial Surveillance Activation List 
16

Table 9.D.8 Offshore Aerial Dispersant Activation List 
17

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

Table 9.D.10 Subsea Dispersant Package Activation List 
18

Table 9.D.11 In-Situ Burn Equipment Activation List 
19

Table 9.D.11 In-Situ Burn Equipment Activation List (continued) 
20

Table 9.D.12 Shoreline Protection and Wildlife Support List 
SECTION 10: Environmental Monitoring Information

A. Monitoring Systems 

A rig based Acoustic Doppl er Current Profiler (ADCP) is used to c ontinuously monitor the current beneath 

the rig. Metocean conditions such as s ea states, wind speed, ocean currents, etc. will also be continuously 

monitored 

B. Incidental Takes 

No incidental takes are anticipated. Shell implements the mitigation measures and monitors for incidental 

takes of protected species according to the followin g notices to lessees and operators from the Minerals 

Management Service: 

• NTL No.2007-G02 “Implementation of Seismic Survey Mitigation Measures and Protected Species 

Observer Program” – during seismic operations

• NTL No.2007-G03 “Marine Trash and Debris Awareness and Elimination” 

• NTL No.2007-G04 “Vessel Strike Avoidance and Injured/Dead Protected Species Reporting” 

C. Flower Garden Banks National Marine Sanctuary 

The activities proposed in this Plan are not in the vicinity of the Protective Zones of the Flower Garden 

Banks Sanctuary and Stetson Bank. 
SECTION 11: Lease Stipulation Information

Leases OCS-G 24112, OCS-G 7957 & 7962 are not located in a Biological Sensitive Area or Shipping Fairway, 

or Military Warning Area. They are designated as ha ving a hi gh potential for containing archeological 

properties and are located within 200 kilometers of the Breton Wilderness Area. 

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 requirem ents and Shell policies. Project ac tivities will b e 

conducted in accordance with the Regi onal Oil Spill Response Plan. The EIA attached as Section 18 to 

this plan discusses impacts and mitigation measures.

B. Incidental Takes 

We do n ot anticipate any incidental t akes related to the prop osed 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 BOEMRE: 

NTL No.2007-G03 “Marine Trash and Debris Awareness and Elimination” 

NTL No.2007-G04 “Vessel Strike Avoidance and Injured/Dead Protected Species Reporting” 

SECTION 13: Related Facilities and Operations Information

Information regarding Rel ated Facilities and Oper ations 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 

Maximum No. In Area at 

Any Time 

Trip Frequency or 

Duration 

Crew Boats 1040 2 Twice per week 

Offshore Support Vessels 8333 4 15 days/well 

Tug Boats NA NA NA 

Anchor Handling Vessel NA NA NA 

Helicopter 22 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 359,720 (gals) 1 week Port Fourchon to MC 762 

C. Drilling Fluids Transportation 

Type of Material Quantity Being Transported Transportation Method 

Dry Mud Chemicals 10-50 lb bags On flats on supply boat 

Synthetic-base drilling fluid 

(base oil) 25 bbl Tote Tanks On deck of supply boats 

D. Solid and Liquid Wastes Transportation 

See table 7B. 

E. Vicinity Map 

See Attached. 

SECTION 15: Onshore Support Facilities Information

A. General 

Name Location Existing/New/Modified 

Fourchon Port Fourchon, LA Existing 

Boothville PHI Heliport Boothville, LA Existing 

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

and Fouchon, Louisiana. The Fouchon boat facilit y is operated by SOI and is located on Bayou 

LaFourche, south of Leesville, LA approximately 3 miles from the Gulf of Mexic o. The Boothville 

heliport is operated by PHI and is located at 38963 La State Highway 23 in Boothville, LA.

B. Support Base Construction or Expansion 

The actions proposed in this Plan will not generate base construction or expansion. 

C. Support Base Construction or Expansion Timetable 

The actions proposed in this Plan will not generate base construction or expansion. 

D. Waste Disposal 

See table 7B 

SECTION 16: Sulphur Operations Information

Information regarding Sulfur Operation s Information is no t included in this SEP as such inf ormation is only 

necessary in the case of DOCDs. 

 
SECTION 17: Coastal Zone Management Act (CZMA) Information

LOUISIANA

COASTAL ZONE MANAGEMENT 

CONSISTENCY CERTIFICATION 

INITIAL EXPLORATION PLAN 

Type of Plan 

Mississippi Canyon Block 762, 805 & 806

Blocks 

OCS-G 07957, OCS-G 24112 & OCS-G 07962

Lease Numbers 

The proposed activities described in detail in this Plan will co mply with Lo uisiana's State and Local Coastal 

Resources Management Act of 1978, Co astal Resources Program, and Coastal Area Management Enforc eable 

Policies. 

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

SHELL OFFSHORE INC. (SOI)

Operator 

___________________________________________ 

Sylvia A. Bellone 

Certifying Official 

04/12/2011

Date 

 
SECTION 17: Coastal Zone Management Act (CZMA) Information

TEXAS

COASTAL ZONE MANAGEMENT 

CONSISTENCY CERTIFICATION 

INITIAL EXPLORATION PLAN 

Type of Plan 

Mississippi Canyon Block 762, 805 & 806

Blocks 

OCS-G 07957, OCS-G 24112 & OCS-G 07962

Lease Numbers 

The proposed activities described in detail in this Plan will co mply with Lo uisiana's State and Local Coastal 

Resources Management Act of 1978, Co astal Resources Program, and Coastal Area Management Enforc eable 

Policies. 

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

SHELL OFFSHORE INC. (SOI)

Operator 

___________________________________________ 

Sylvia A. Bellone 

Certifying Official 

04/12/2011

Date 
Coastal Zone Management Consistency Information 

For the State of Texas 

In accordance with Subpart E of 15 CFR 903 “Consisten cy for Outer Conti nental Shelf (OCS) Exploration, 

Development and Production Activities” and as required by 15 CFR 930.58, Shell Offshore INC (SOI) is hereby 

providing the following in formation in support of the Environmental Impact. 15 CF R 930.58 iden tifies 

necessary data and information to be furnished to the State agency. The information is as follows: 

(a) CONSISTENCY CERTIFICATION

A Coastal Zone Consistency Certification for activities that affect the State of Texas is provided as Attachm ent 

17A of the above-mentioned EP. 

(b) OTHER INFORMATION

(1) A detailed d escription of the prop osed activities, coastal effects, and c omprehensive information 

sufficient to support this Consi stency Certification is presented in Attachment 18 of the abovementioned EP. As per A ttachment 1 to Appendix I of NTL 2002-G08, the foll owing items have been 

identified as being required: 

• A discussion of the method of disposal of wastes and discharges is provided 

 in Attachment 7 of this DOCD. 

• Oil Spill Information is provided in Attachment 9 of this DOCD. All operations are covered by Shell 

Offshore Inc's Regional Oil Spill Response Plan , which has been approved by MMS. Th e Plan is 

available upon request. 

(2) Following is an evaluation that includes findings relating the coastal effects of the proposed activities 

and associated facilities to the relev ant enforceable policies of the Texas’ Coastal Management Program

(TCMP), Title 31, Part 16, Chapter 501, Subchapter B:

(Category 2) 

Construction, Operation & Maintenance of Oil & Gas Exploration & Production Facilities 

No operations are proposed in or near any critical areas. No facility construction or expansion is proposed as a 

result of this activity. The proposed activities are located approximately 120 miles from the Texas shoreline; 

therefore we expect no adverse impacts to CNRAs or beach access and use rights of the public. All activities 

shall be conducted in a manner that minimizes significant impacts to coastal resources. No adverse effects to 

Texas’ coastal area are expected in association with the proposed activities. 

(Category 3) 

Discharges of Wastewater and Disposal of Waste from Oil and Gas Exploration and Production 

Activities 

No discharge of wastewater or di sposal of waste from the proposed activities will occur in the Texas’ coastal 

zone, therefore no impact to Texas’ coastal waters is expected. 

(Category 4) 

Construction and Operation of Solid Waste Treatment, Storage, and Disposal Facilities 

No construction of solid waste facilities or expansion of existing facilities in the coastal zone are proposed in 

the attached plan, therefore, no adverse effects on any features of Texas’ coastal cone are expected. 

(Category 5) 

Prevention, Response, and Remediation of Oil Spills 

The proposed activities will be covered under an approved Regional Oil Spill Response Plan. The plan is in 

place, practiced, and updated as necessary. The best practical techniques shall be utiliz ed to preven t the 

release of pollutants or toxic substances into the environment. All involved vessels and facilities are designed 

to be capabl e of prompt response an d adequate re moval of acci dental discharges of oil. In addition, the 

proposed activities are 120 miles from shore; therefore no damages to natural resources are expected as the 

result of an unauthorized discharge of oil into coastal waters. 
(Category 6) 

Discharge of Municipal and Industrial Waste Water to Coastal Waters 

No discharges from the proposed activities will occur in coastal waters. The proposed activities are 142 miles 

from shore; therefore there will be no effect on coastal waters. 

(Category 8) 

Development in Critical Areas 

None of the proposed activities will occur in a critic al area; therefore no effects to Texas’ coastal zone are 

expected. The activity will not jeop ardize the c ontinued existence of species listed as endangered or 

threatened, and will not result in likelihood of the destruction or adverse modification of a habitat determined 

to be a critical habitat under the Endangered Species Act. The activity will not cause or contribute to violation 

of any applicable surface water quality standards. The activity will not violate any requirement imposed to 

protect a marine sanctuary. 

(Category 9) 

Construction of Waterfront Facilities and Other Structures on Submerged lands 

No waterfront facilities or other structures are proposed on submerged lands in the Texas coastal zone, 

therefore the proposed activities are not expected to have any adverse impacts on submerged lands. 

(Category 10) 

Dredging and Dredged Material Disposal and Placement 

No dredging or disposal/placement of dredged material is proposed, therefore no adverse effects to coastal 

waters, submerged lands, critical areas, coastal shore areas, or Gulf beaches are expected. 

(Category 11) 

Construction in the Beach / Dune System 

The proposed activities do not include any construc tion projects in critical dune areas or areas adj acent to or 

on Gulf beaches, therefore, no impact to Texas’ beach or dune systems are expected. 

(Category 15) 

Alteration of Coastal Historic Areas 

The proposed activities d o not include any alter ation or disturbance of a coastal hi storic area; therefore, no 

impacts to are expected to adversely affect any historical, architectural, or archaeological site in Texas’ coastal 

zone. 

(Category 16) 

Transportation 

The proposed activities d o not includ e any transportation construction projects within the coastal z one; 

therefore, no impacts to Texas’ coastal zone are expected. 

(Category 17) 

Emission of Air Pollutants 

The proposed activities shall be carried out in c onformance with applicable air quality laws, stand ards, and 

regulations. Emissions from the proposed activities are not expected to h ave significant 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 proposed activities will occur approximately 12 0 miles from the 

Texas shore and will be within the exemption limits set by BOEM, therefore, no impacts to Texas’ coastal zone 

is expected. 

(Category 18) 

Appropriations of Water 

The proposed activities do not include the impoundment or diversion of state water, therefore, no impacts to 

Texas’ coastal zone is expected. 

(Category 20) 

Marine Fishery Management 

The proposed activities are located approximately 120 miles from shore and are not expected to have any 

effect on marine fishery management or fishery migratory patterns within waters in the coastal zone of Texas. 
(Category 22) 

Administrative Policies 

The necessary information for applicable agencies to make an informed decision on the proposed activities has 

been provided 

In conclusion, all activities shall be consistent with Texas’ coastal management program and shall comply with 

all relevant rules and regulations. No activities are planned within any critical areas. Activiti es will be carried 

out avoid unnecessary conflicts with other uses of the vicinity. 

 
SECTION 18: Environmental Impact Analysis

Environmental Impact Analysis 

INITIAL EXPLORATION PLAN 

Mississippi Canyon Block 762 (OCS-G 7957) 

Mississippi Canyon Block 805 (OCS-G 24112) 

Mississippi Canyon Block 806 (OCS-G 7962) 

Offshore Louisiana 

 April 2011 

Prepared for: 

Sylvia Bellone 

Shell Offshore Inc. 

P.O. Box 61933 

New Orleans, Louisiana 70161 

Telephone: (504) 728-7215 

Prepared by: 

CSA International, Inc. 

8502 SW Kansas Avenue 

Stuart, Florida 34997 

Telephone: (772) 219-3000 
Mississippi Canyon Blocks 762, 805, and 806 April 2011

Environmental Impact Analysis for Initial EP Page ii

Contents

Page 

Introduction ................................................................................................................1

Project Summary ....................................................................................................................................1

Purpose of the EIA..................................................................................................................................3

OCS Regulatory Framework ................................................................................................................... 3

Oil Spill Prevention and Contingency Planning ...................................................................................... 4

EIA Organization.....................................................................................................................................4

A.  Impact‐Producing Factors .......................................................................................6

A.1 Drilling Rig and Drillship Presence (including noise and lights)..................................................... 6

A.2 Physical Disturbance to the Seafloor ............................................................................................ 6

A.3 Air Pollutant Emissions................................................................................................................ 10

A.4 Effluent Discharges...................................................................................................................... 11

A.5 Water Intake................................................................................................................................12

A.6 Onshore Waste Disposal ............................................................................................................. 12

A.7 Marine Debris.............................................................................................................................. 12

A.8 Support Vessel and Helicopter Traffic......................................................................................... 13

A.9 Accidents.....................................................................................................................................13

A.9.1 Types of Accidents Evaluated.......................................................................................... 13

A.9.2 Small Fuel Spill................................................................................................................. 14

A.9.3 Crude Oil Spill (Worst Case Discharge)............................................................................ 15

A.9.4 Other Accidents Not Analyzed in Detail .......................................................................... 17

B.  Affected Environment...........................................................................................18

C.  Impact Analysis.....................................................................................................21

C.1 Physical/Chemical Environment.................................................................................................. 21

C.1.1 Air Quality........................................................................................................................ 21

C.1.2 Water Quality .................................................................................................................. 23

C.2 Seafloor Habitats and Biota......................................................................................................... 25

C.2.1 Soft Bottom Benthic Communities.................................................................................. 26

C.2.2 High‐Density Deepwater Benthic Communities.............................................................. 28

C.2.3 Designated Topographic Features................................................................................... 30

C.2.4 Pinnacle Trend Area Live Bottoms................................................................................... 30

C.2.5 Eastern Gulf Live Bottoms............................................................................................... 31

C.3 Threatened, Endangered, and Protected Species and Critical Habitat.......................................31

C.3.1 Sperm Whale (Endangered) ............................................................................................ 33

C.3.2 Florida Manatee (Endangered)........................................................................................ 36

C.3.3 Endangered Mysticete Whales........................................................................................ 37

C.3.4 Non‐Endangered Marine Mammals (Protected)............................................................. 38

C.3.5 Sea Turtles (Endangered/Threatened)............................................................................ 41

C.3.6 Piping Plover (Threatened).............................................................................................. 44

C.3.7 Whooping Crane (Endangered)....................................................................................... 46
Contents

(Continued)

Page 

Mississippi Canyon Blocks 762, 805, and 806 April 2011

Environmental Impact Analysis for Initial EP Page iii

C.3.8 Gulf Sturgeon (Threatened)............................................................................................. 47

C.3.9 Beach Mice (Endangered)................................................................................................ 48

C.4 Coastal and Marine Birds ............................................................................................................ 49

C.4.1 Marine and Pelagic Birds................................................................................................. 49

C.4.2 Shorebirds and Coastal Nesting Birds.............................................................................. 51

C.5 Fisheries Resources..................................................................................................................... 54

C.5.1 Pelagic Communities and Ichthyoplankton..................................................................... 54

C.5.2 Essential Fish Habitat....................................................................................................... 56

C.6 Archaeological Resources............................................................................................................ 59

C.6.1 Shipwreck Sites................................................................................................................ 59

C.6.2 Prehistoric Archaeological Sites ...................................................................................... 60

C.7 Coastal Habitats and Protected Areas......................................................................................... 60

C.8 Socioeconomic and Other Resources.......................................................................................... 63

C.8.1 Recreational and Commercial Fishing ............................................................................. 63

C.8.2 Public Health and Safety.................................................................................................. 65

C.8.3 Employment and Infrastructure ...................................................................................... 66

C.8.4 Recreation and Tourism .................................................................................................. 66

C.8.5 Land Use .......................................................................................................................... 67

C.8.6 Other Marine Uses .......................................................................................................... 68

C.9 Cumulative Impacts..................................................................................................................... 68

C.9.1 Cumulative Impacts to Physical/Chemical Resources..................................................... 69

C.9.2 Cumulative Impacts to Biological Resources................................................................... 70

C.9.3 Cumulative Impacts to Socioeconomic Resources.......................................................... 72

D.  Environmental Hazards.........................................................................................73

D.1 Geologic Hazards......................................................................................................................... 73

D.2 Severe Weather........................................................................................................................... 73

D.3 Currents and Waves.................................................................................................................... 73

E.  Alternatives ..........................................................................................................73

F.  Mitigation Measures.............................................................................................73

G.  Consultation.........................................................................................................74

H.  Preparers..............................................................................................................75

I.  References.............................................................................................................75
Mississippi Canyon Blocks 762, 805, and 806 April 2011

Environmental Impact Analysis for Initial EP Page iv

List of Tables

Table Page 

1 Notices to Lessees and Operators (NTLs) that are referenced in this Environmental

Impact Analysis (EIA) ............................................................................................................. 5

2 Matrix of impact‐producing factors and affected environmental resources........................7

3 Conditional probabilities of a spill in the lease area contacting shoreline segments

(From: Ji et al., 2004)........................................................................................................... 16

4 Benthic community data from stations near the lease area and in similar water

depths sampled during the Northern Gulf of Mexico Continental Slope Habitats

and Benthic Ecology Study (From: Wei, 2006; Rowe and Kennicutt, 2009)........................26

5 Federally‐listed endangered and threatened species in the lease area and along

the northern Gulf coast....................................................................................................... 32

List of Figures

Figure Page 

1 Vicinity map for the lease area.............................................................................................. 2

2 Bathymetric map of the lease area showing proposed well surface locations...................20

3 Location of selected environmental features in relation to the lease area........................45
Mississippi Canyon Blocks 762, 805, and 806 April 2011

Environmental Impact Analysis for Initial EP Page v

Acronyms and Abbreviations

ADIOS Automated Data Inquiry for Oil Spills

ASI Airborne Support, Inc.

BOEMRE Bureau of Ocean Energy Management,

Regulation and Enforcement

BPD barrels per day

CCA Clean Caribbean & Americas  

CGA Clean Gulf Associates

CH4 methane

CO carbon monoxide

CO2 carbon dioxide  

EA Environmental Assessment

EEZ Exclusive Economic Zone

EFH Essential Fish Habitat

EIA Environmental Impact Analysis

EIS Environmental Impact Statement

EP Exploration Plan

ESR enhanced surface renderings

ESA Endangered Species Act

FAD fish‐attracting device

GMFMC Gulf of Mexico Fishery Management

Council

H2S hydrogen sulfide

HAPC Habitat Area of Particular Concern

HSE health, safety, and environment

IPF impact‐producing factor

ISB in‐situ burning

ISO International Organization for

Standardization

MARPOL International Convention for the

Prevention of Pollution from Ships

MC Mississippi Canyon

MGD million gallons per day

MMBO million barrels of oil

MMPA Marine Mammal Protection Act

MMS Minerals Management Service

MSRC Marine Spill Response Corporation

MWCC Marine Well Containment Company

NAAQS National Ambient Air Quality Standards

NEPA National Environmental Policy Act

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric

Administration

NOx nitrogen oxides

NPDES National Pollutant Discharge Elimination

System

NPS National Park Service

NRC National Research Council

NTL Notice to Lessees

NWR National Wildlife Refuge

OCS Outer Continental Shelf
Acronyms and Abbreviations 

(Continued) 

Mississippi Canyon Blocks 762, 805, and 806 April 2011

Environmental Impact Analysis for Initial EP Page vi

OCSLA Outer Continental Shelf Lands Act

OSAT Operational Science Advisory Team

OSRA Oil Spill Risk Analysis

OSRL Oil Spill Response Limited

OSRP Oil Spill Response Plan

PAH polycyclic aromatic hydrocarbon

PM particulate matter

PSD Prevention of Significant Deterioration

ROV remotely operated vehicle

SBM synthetic‐based mud

SOx sulfur oxides

SWSS Sperm Whale Seismic Study

USCG U.S. Coast Guard

USDOI U.S. Department of the Interior

USEPA U.S. Environmental Protection Agency

VOC volatile organic compound

USFWS U.S. Fish and Wildlife Service

WCD worst case discharge

WCEP Whooping Crane Eastern Partnership

WMA Wildlife Management Area
Mississippi Canyon Blocks 762, 805, and 806 April 2011

Environmental Impact Analysis for Initial EP Page 1

Introduction

Project Summary

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

(MC) Blocks 762, 805, and 806.  Shell’s Initial EP for wells D, E and F in MC 762 was approved by

the Minerals Management Service (MMS, now the Bureau of Ocean Energy Management,

Regulation and Enforcement [BOEMRE]) on October 16, 2003 (Plan Control No. S‐06278).  

Subsequent to this another Initial EP for MC 762 was approved by the MMS on December 16,

2008 (Plan Control No. S‐07273) that included wells G, H, I, J, K, and L.  Shell is now submitting

another Initial EP that includes eight (8) development wells.  These are wells M, N, O, P, Q, R, S,

and T.  This Initial EP also incorporates the revised blowout scenario and worst case discharge

(WCD) information as required by Notice to Lessees (NTL) 2010‐N06.

The lease area is 51 miles (82 km) from the nearest shoreline, 100 miles (161 km) from the

onshore support base at Port Fourchon, Louisiana, and 77 miles (124 km) from the helicopter

base at Boothville, Louisiana (Figure 1).  Water depths at the wellsites range from 957 to 961 m

(3,140 to 3,152 ft).

The Noble Jim Day, a semisubmersible dynamically positioned rig, and the Noble Bully I, a

dynamically positioned drillship, or similar rigs will be used for drilling and completion of the

proposed wells.  Drilling of wells is planned to commence during July 2011 and should be

finished, along with completions, by the end of 2016.  The average time to drill and complete a

well will be approximately 120 and 60 days, respectively.   
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Figure 1. Vicinity map for the lease area.
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Purpose of the EIA

This Environmental Impact Analysis (EIA) was prepared pursuant to the requirements of the

Outer Continental Shelf Lands Act (OCSLA), 43 U.S.C. §§ 1331‐1356, and BOEMRE regulations,

including 30 CFR 250.212(o) and 250.227.  The EIA is a project‐ and site‐specific analysis of

Shell’s planned activities under this Initial EP.  The EIA also evaluates potential impacts in

accordance with NTL 2008‐G04 issued by the BOEMRE.   

The EIA presents data, analysis, and conclusions to support the preparation of an EA by the

BOEMRE, as required by the National Environmental Policy Act (NEPA). The EIA documents

Shell’s compliance with other relevant Federal laws, including the Endangered Species Act (ESA)

and Marine Mammal Protection Act (MMPA), and supports the BOEMRE’s approval of this

Initial EP.  It also identifies the mitigation measures Shell will implement in connection with the

planned activities.

As specified in NTL 2008‐G04, an EIA is a project‐specific analysis that focuses on the impacts of

a specific plan.  This EIA addresses the impact‐producing factors (IPFs), resources, and impacts

associated with the activities proposed in this Initial EP including drilling and completion of

wells.  The EIA also incorporates the revised blowout scenario and WCD information required by

NTL 2010‐N06.

The BOEMRE has performed numerous environmental evaluations of oil and gas activities on

the Gulf of Mexico Outer Continental Shelf (OCS).  Potential impacts have been analyzed at a

broader level in the Programmatic Environmental Impact Statement (EIS) for the OCS Oil and

Gas Leasing Program (MMS, 2007a) and in recent multi‐lease‐sale EISs for the Western and

Central Gulf of Mexico Planning Areas (MMS, 2007b, 2008), as well as the Environmental

Assessment (EA) for Gulf of Mexico deepwater operations and activities (MMS, 2000) and a Grid

EA for the Medusa Development in MC 538 and 582 (Grid 12) (MMS, 2002).

These studies provide data and a large body of knowledge on the Gulf of Mexico OCS.  They

analyze everything from potential impacts on the natural environment to the socioeconomic

effects of exploration and development activities.  They include numerous technical studies

ranging from the likely trajectory of spilled oil to the effects of underwater noise on threatened

and endangered species.  They inform agency decision‐making on lease offerings, mitigation

measures and lease stipulations, operational requirements, and permit restrictions.  This

substantial body of work, which in part forms the basis for the evaluation presented here, will

allow the BOEMRE and other regulatory agencies to evaluate Shell’s Initial 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‐specific and

site‐specific analyses.

OCS Regulatory Framework

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

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

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

BOEMRE is charged with the responsibility of managing and regulating the development of OCS
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Environmental Impact Analysis for Initial EP Page 4

oil and gas resources in accordance with the provisions of the OCSLA.  The BOEMRE operating

regulations are in 30 CFR Parts 250, 251, and 254.

In implementing its responsibilities under the OCSLA and NEPA, the BOEMRE must consult

numerous Federal departments and agencies that have authority to govern and maintain ocean

resources pursuant to other Federal laws.  Among these are the U.S. Coast Guard (USCG),

U.S. Environmental Protection Agency (USEPA), U.S. Fish and Wildlife Service (USFWS), and the

National Oceanic and Atmospheric Administration (NOAA) through the National Marine

Fisheries Service (NMFS).  Federal regulations establish consultation and coordination processes

with Federal, State, and local agencies (e.g., the ESA, MMPA, Coastal Zone Management Act of

1972, and the Magnuson‐Stevens Fishery Conservation and Management Act).

NTLs are formal documents issued by the BOEMRE that provide clarification, description, or

interpretation of a regulation or standard; provide guidelines on implementing a special lease

stipulation or regional requirement; provide a better understanding of the scope and meaning

of a regulation by explaining the BOEMRE interpretation of a requirement; or transmit

administrative information such as current telephone listings or changes in the BOEMRE

personnel or office address.  Table 1 lists and summarizes the NTLs that are referenced in this

EIA.

Oil Spill Prevention and Contingency Planning

Shell submitted a Gulf of Mexico Regional Oil Spill Response Plan (OSRP) to the BOEMRE as a

fundamental component of the planned drilling program on October 26, 2010.  A letter

submitted and accepted by the BOEM on December 3, 2010 certifies that Shell has the capability

to respond to the maximum extent practicable to a WCD (30 CFR 254.2).  The OSRP

demonstrates Shell’s capabilities to rapidly and effectively manage oil spills that may result from

drilling operations.  Despite the extremely low likelihood of a large oil spill event occurring

during the project, Shell has designed its response program based upon a regional capability of

responding to a range of spill volumes that increase from small operational spills up to and

including a WCD from a well blowout.  Shell’s program meets the response planning

requirements of the relevant coastal states and Federal oil spill planning regulations.  The OSRP

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

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

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

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

to implement effective and sustained spill containment and recovery operations.

EIA Organization

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

NTL 2008‐G04, which provides guidance regarding information required by 30 CFR Part 250 for

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

Section C (Impact Analysis).
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Table 1. Notices to Lessees and Operators (NTLs) that are referenced in this Environmental

Impact Analysis (EIA).

NTL Title Summary 

2010-

N10 

Statement of Compliance with 

Applicable Regulations and 

Evaluation of Information 

Demonstrating Adequate Spill 

Response and Well Containment 

Resources 

Informs operators using subsea blowout preventers (BOPs) 

or surface BOPs on floating facilities that applications for 

well permits must include a statement signed by an 

authorized company official stating that the operator will 

conduct all activities in compliance with all applicable 

regulations, including the increased safety measures 

regulations (75 FR 63346). Informs operators that the 

BOEMRE will be evaluating whether each operator has 

submitted adequate information demonstrating that it has 

access to and can deploy containment resources to 

promptly respond to a blowout or other loss of well control. 

2010-N0

6 

Information Requirements for 

Exploration Plans, Development 

and Production Plans, and 

Development Operations 

Coordination Documents on the 

OCS 

Rescinds the limitations set forth in NTL 2008-G04 

regarding a blowout scenario and worst case discharge 

scenario, and provides guidance regarding the information 

required in blowout scenario and worst case discharge 

scenario descriptions. 

2009-G4

0 Deepwater Benthic Communities 

Guidance for avoiding and protecting high-density 

deepwater benthic communities (including chemosynthetic 

and deepwater coral communities) from damage caused by 

Outer Continental Shelf (OCS) oil and gas activities in water 

depths greater than 300 m (984 ft). Prescribes separation 

distances of 610 m (2,000 ft) from each mud and cuttings 

discharge location and 76 m (250 ft) from all other seafloor 

disturbances. 

2009-G3

9 

Biologically-Sensitive Underwater 

Features and Areas 

Guidance for avoiding and protecting biologically sensitive 

features and areas (i.e., topographic features, pinnacles, 

low-relief live bottom areas, and other potentially sensitive 

biological features) when conducting OCS operations in 

water depths less than 300 m (984 ft) in the Gulf of Mexico. 

2009-

G06 

Military Warning and Water Test 

Areas 

Provides contact links to individual command headquarters 

for the military warning and water test areas in the Gulf of 

Mexico. Lease stipulations require lessees or designated 

operators to enter into an agreement with the appropriate 

individual military command headquarters concerning the 

control of electromagnetic emissions and use of boats and 

aircraft in the applicable warning area or water test area 

before commencing such traffic. 

2008-G0

4 

Information Requirements for 

Exploration Plans and 

Development Operations 

Coordination Documents 

Guidance on the information requirements for OCS plans, 

including EIA requirements and information regarding 

compliance with the provisions of the Endangered Species 

Act and Marine Mammal Protection Act. 

2007-

G04 

Vessel Strike Avoidance and 

Injured/Dead Protected Species 

Reporting 

Recommends protected species identification training, 

recommends that vessel operators and crews maintain a 

vigilant watch for marine mammals and slow down or stop 

their vessel to avoid striking protected species, and requires 

operators to report sightings of any injured or dead 

protected species. 

2007-G0

3 

Marine Trash and Debris 

Awareness and Elimination 

Instructs operators to exercise caution in the handling and 

disposal of small items and packaging materials; requires 

the posting of placards at prominent locations on offshore 

vessels and structures; and mandates a yearly marine trash 

and debris awareness training and certification process. 

2005-

G07 

Archaeological Resource 

Surveys and Reports 

Provides guidance on regulations regarding archaeological 

discoveries, specifies requirements for archaeological 

resource surveys and reports, and outlines options for 

protecting archaeological resources. 
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A.  Impact‐Producing Factors

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

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

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

effect, an analysis is provided in Section C.  Potential IPFs for the proposed activity are listed

below and briefly discussed in the following subsections:

• Drilling rig and drillship presence (including noise and lights);

• Physical disturbance to the seafloor;

• Air pollutant emissions;

• Effluent discharges;

• Water intake;

• Onshore waste disposal;  

• Marine debris;

• Support vessel and helicopter traffic; and

• Accidents.

A.1 Drilling Rig and Drillship Presence (including noise and lights)

The wells will be drilled using the Noble Jim Day , the Noble Bully I or similar rigs.  A rig will be

on site for an estimated 120 days per well for development drilling and approximately 60 days

per well for completion.  Four offshore support vessels will be in the vicinity of the drilling rig or

drillship to provide assistance as necessary.  The physical presence of a drilling rig or drillship in

the ocean can attract pelagic fishes and other marine life, as discussed in Section C.5.1.  

Dynamically positioned drilling rigs and drillships are self‐propelled and maintain position over a

well with a dynamic positioning system (computer controlled thrusters).  

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

including infrasonic frequencies in at least some cases (MMS, 2000).  According to Richardson et

al. (1995), more sound is generally radiated underwater from drillships during drilling operations

than from semisubmersibles, but this changes with the level of activity and age of equipment on

the vessel.  Drilling rigs and drillships also maintain exterior lighting for navigational and aviation

safety in accordance with Federal regulations.

A.2 Physical Disturbance to the Seafloor

Neither the dynamically positioned rig nor the drillship requires the use of anchors for holding

or stability purposes during drilling and completion operations.  As a result, there will be

minimal physical disturbance to the seafloor due to the presence of the drilling rig or drillship.  

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

positioning of the wellbore and BOP.  Physical disturbance of the seafloor will be limited to the

area where the wellbore penetrates the substrate, where mud and drill cuttings will be

deposited.   
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Table 2. Matrix of impact‐producing factors and affected environmental resources. X = potential impact; dash (‐‐) = no imp

Environmental Resources 

Impact-producing Factors

Drilling Rig 

and Drillship 

Presence 

(incl. noise & 

lights)

Physical 

Disturbanc

e to 

Seafloor 

Air 

Pollutant 

Emissions

Effluent 

Discharge

s 

Water 

Intake 

Onshore 

Waste 

Disposal 

Marine 

Debris 

Sup

Vess

o T

Physical/Chemical Environment 

Air quality and greenhouse gases -- -- X -- -- -- -- Water quality -- -- -- X -- -- -- 

Seafloor Habitats and Biota 

Soft bottom benthic communities -- -- -- X -- -- -- High-density deepwater benthic communities -- --(4) -- --(4) -- -- -- Designated topographic features -- --(1) -- --(1) -- -- -- Pinnacle trend area live bottoms -- --(2) -- --(2) -- -- -- Eastern Gulf live bottoms -- --(3) -- --(3) -- -- -- 

Threatened, Endangered, and Protected Species and Critical Habitat

Sperm whale (endangered) X(8) -- -- -- -- -- -- XFlorida manatee (endangered) -- -- -- -- -- -- -- XEndangered mysticete whales -- -- -- -- -- -- -- Non-endangered marine mammals (protected) X -- -- -- -- -- -- Sea turtles (endangered/threatened) X(8) -- -- -- -- -- -- XPiping Plover (threatened) -- -- -- -- -- -- -- Whooping Crane (endangered) -- -- -- -- -- -- -- Gulf sturgeon (threatened) -- -- -- -- -- -- -- Beach mice (endangered) -- -- -- -- -- -- -- 

Coastal and Marine Birds 

Marine and pelagic birds X -- -- -- -- -- -- Shorebirds and coastal nesting birds -- -- -- -- -- -- -- 

Fisheries Resources 

Pelagic communities and ichthyoplankton X -- -- X X -- -- Essential Fish Habitat X -- -- X X -- -- 

Archaeological Resources 

Shipwreck sites -- --(7) -- -- -- -- -- Prehistoric archaeological sites -- --(7) -- -- -- -- -- 

Coastal Habitats and Protected Areas 

Beaches -- -- -- -- -- -- -- Wetlands and seagrass beds -- -- -- -- -- -- -- Coastal wildlife refuges & wilderness areas -- -- -- -- -- -- -- 

Socioeconomic and Other Resources 

Recreational and commercial fishing X -- -- -- -- -- -- Public health and safety -- -- -- -- -- -- -- Employment and infrastructure -- -- -- -- -- -- -- Recreation and tourism -- -- -- -- -- -- -- Land use -- -- -- -- -- -- -- Other marine uses -- -- -- -- -- -- -- 
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WCD = worst case discharge.
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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 or near any marine sanctuary, topographic feature, or 

no-activity zone. There are no submarine banks in the blocks. 

(2) Activities with any bottom disturbance within an OCS lease block protected through the Live Bottom 

(Pinnacle Trend) Stipulation attached to an OCS lease. 

• The Live Bottom (Pinnacle Trend) Stipulation is not applicable to the lease area. 

(3) Activities within any Eastern Gulf OCS block where seafloor habitats are protected by the Live Bottom 

(Low-Relief) Stipulation attached to an OCS lease. 

• The Live Bottom (Low-Relief) Stipulation is not applicable to the lease area. 

(4) Activities on blocks designated by the BOEMRE as being in water depths 300 m or greater. 

• No impacts on high-density deepwater benthic communities are anticipated. There are no 

features indicative of high-density chemosynthetic communities or coral communities within 

610 m (2,000 ft) of any drilling mud/cuttings discharge location. There will be no anchoring 

associated with the drilling platform that could impact such communities if they were present. 

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

encountered. 

• Based on CFR 250.417(c), Shell is requesting that the BOEMRE classify the area as “H2S 

absent.” 

(6) All activities that could result in an accidental spill of produced liquid hydrocarbons or diesel fuel that you 

determine would impact these environmental resources. If the proposed action is located a sufficient 

distance from a resource that no impact would occur, the EIA can note that in a sentence or two. 

• Accidental hydrocarbon spills could affect the resources marked (X) in the matrix, and impacts 

are analyzed in Section C. 

(7) All activities that involve seafloor disturbances, including anchor emplacements, in any OCS block 

designated by the BOEMRE as having high-probability for the occurrence of shipwrecks or prehistoric 

sites, including such blocks that will be affected that are adjacent to the lease block in which your 

planned activity will occur. If the proposed activities are located a sufficient distance from a 

shipwreck or prehistoric site that no impact would occur, the EIA can note that in a sentence or two. 

• No impacts on archaeological resources are expected. The lease area is on the list of highprobability blocks for shipwrecks. The archaeological assessment for Block 762 and vicinity 

found 1,152 unidentified sonar contacts. However the seafloor patterning and acoustic 

characteristics conclude that these are modern debris. The lease is well beyond the 60-m depth 

contour used by the BOEMRE as the seaward extent for prehistoric archaeological site potential 

in the Gulf of Mexico. 

(8) All activities that you determine might have an adverse effect on endangered or threatened marine 

mammals or sea turtles or their critical habitats. 

• IPFs that may affect marine mammals, sea turtles, or their critical habitats include drilling rig and 

drillship presence and emissions, support vessel and helicopter traffic, and accidents. See 

Section C. 

(9) Production activities that involve transportation of produced fluids to shore using shuttle tankers or 

barges. 

• Not applicable.
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A.3 Air Pollutant Emissions

Air pollutant emissions are estimated in Initial EP Section 8.  Offshore air pollutant emissions

will result from operations of the drilling rig and drillship, as well as service vessels and

helicopters.  These emissions occur mainly from combustion of diesel fuel.  The combustion of

fuels occurs on diesel‐powered generators, pumps, or motors and from lighter fuel motors.  

Primary air pollutants typically associated with OCS activities are suspended particulate matter

(PM), sulfur oxides (SOx), nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon

monoxide (CO).

The Air Quality Emissions Report prepared in accordance with BOEMRE requirements

shows that the projected emissions for the drilling rig and drillship are below exemption

levels; therefore, according to 30 CFR 250.303, the emissions will not significantly affect

the air quality of the onshore area for any of the criteria pollutants.  No further analysis

is required. However Shell is using emission reduction measures and modified emission

factors. These are described below along with proposed permit limitations to ensure

compliance with estimated emissions:  

Bully Rig MAIN ENGINES

1. NOx ‐ Certified EPA Marine Tier 2 engines, for NOx. Emission factor = 5.8 gm/hp‐hr

Compliance with the Tier 2 emission standards will be assured via normal operation

and maintenance practices as described in the attached EMD Maintenance

procedures. These practices will ensure optimal performance of the engines at the

Tier 2 level. Note these practices have been provisionally accepted by US EPA for the

Bully rig during permitting of emissions in the eastern Gulf (east of 87.5 degrees

longitude).

2. NOx‐ Limit total fuel consumption to main engines on annual basis.

Proposed Limit

Year Total Fuel Consumed by MAIN ENGINES in

the Year, gal

2012 1,469,648

Each year 2013‐2018 5,894,741

Limiting total fuel consumed in the period ensures average annual emissions as

estimated won't be exceeded (while still allowing for short periods of time where

fuel usage may be higher than the daily fuel usage from Column F might be

exceeded due to currents, drilling conditions, etc). Maintain logs of fuel consumed

by all main engines, and rig location. Retain records through duration of EP for

inspection if requested by BOEM.

Noble Jim Day MAIN ENGINES
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NOx‐ Limit total fuel consumption to main engines on annual basis.

Proposed Limit

Year Total Fuel Consumed by MAIN ENGINES in

the Year, gal

2011 2,965,450

2012 923,665

Limiting total fuel consumed in the period ensures average annual emissions as

estimated won't be exceeded (while still allowing for short periods of time where

fuel usage may be higher than the daily fuel usage from Column F might be

exceeded due to currents, drilling conditions, etc). Maintain logs of fuel consumed

by all main engines, and rig location. Retain records through duration of EP for

inspection if requested by BOEM.

Support Vessels

NOX‐ For all periods and all support vessels, all vessels will maintain total engine

HP less than or equal to 50% design load while within 25 nm of rig.  Since

emission estimates assume all vessels are at or below 50% through‐out the

campaign, limiting loads to 50% or less will ensure average annual emissions are

not exceeded in any given year. Maintain logs of all vessel loads and locations.

Retain records through duration of EP for inspection if requested by BOEM.

All diesel engines

SO2‐ limit sulfur content to 0.05% weight sulfur. Compliance is assured because

diesel fuel intended for locomotive, marine and non‐road engines and

equipment is required to meet the Low Sulfur Diesel fuel maximum specification

of 500 ppm sulfur in 2007, per EPA regulation. Diesel fuels with higher sulfur are

not available. http://www.clean‐diesel.org/nonroad.html   

       

A.4 Effluent Discharges

Effluent discharges are summarized in Initial EP Section 7.  All offshore discharges will be in

accordance with the National Pollutant Discharge Elimination System (NPDES) General Permit

No. GMG290000 issued by the USEPA.  Discharges will be in compliance with and monitored as

required by the permit.

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

intervals before the marine riser is set that allows returns to the surface.  Excess cement slurry
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Environmental Impact Analysis for Initial EP Page 12

also will be released at the seafloor during casing installation for the riserless portion of the

drilling operations.

A synthetic‐based mud (SBM) system will be used after the riser is installed.  The SBM will not be

discharged but will be recovered and transported to the shorebase for recycling by the mud

company.  SBM cuttings will be discharged overboard after treatment with a cuttings dryer,

which is expected to reduce retention of the SBM fluid on cuttings to well below the NPDES

permit requirement of 6.9%.  The estimated volume of cleaned SBM cuttings to be discharged is

7,347 barrels (bbl)/well.

Other effluent discharges in accordance with the NPDES permit will include excess cement,

non‐contact cooling water, treated sanitary and domestic wastes, deck drainage, desalination

unit brine, uncontaminated fire water, and ballast water.

A.5 Water Intake

Seawater will be drawn from the ocean for once‐through, non‐contact cooling of machinery on

the drilling rig or drillship.  The estimated intake and discharge of cooling water is

100,000 barrels per day (BPD) (4.19 million gallons per day [MGD]).   

Section 316(b) of the Clean Water Act requires NPDES permits to ensure that the location,

design, construction, and capacity of cooling water intake structures reflect the best technology

available to minimize adverse environmental impact from impingement and entrainment of

aquatic organisms.  The current general NPDES Permit No. GMG 290000 does not specify

requirements for existing facilities (those that started construction before July 16, 2006) and

therefore the cooling water intake permit requirements are not applicable to the Noble Jim Day.  

The Noble Bully I does meet the applicability criteria for a “new” facility as defined by the NPDES

permit and therefore is subject to the cooling water intake permit requirements.  All affected

intakes will be in compliance with the design, monitoring, and recordkeeping requirements of

the NPDES permit.

A.6 Onshore Waste Disposal

Wastes generated during drilling are tabulated in Initial EP Section 7.  Volumes are estimated to

be 7 bbl/day.  Non‐recyclable trash will be transported to the Newpark Environmental Ingleside

or Bridge City, TX.  Other wastes such as paints and chemicals (used cooking oil, used motor oil,

oily rags, antifreeze, aerosol cans, fluorescent bulbs) will be disposed of at Safety Kleen Systems,

Inc., Denton, Texas, or Lamp Environmental Industries, Hammond, Louisiana.  Used oil will be

disposed of at Smiths Incinerator Venice, LA.  Paper, plastics, aluminum cans, and cardboard will

be recycled at Omega Waste Management, Patterson, Louisiana, or ARC of New Iberia via the

Recycle the Gulf Program.  At the onshore facilities, wastes will be recycled or disposed of

according to all applicable regulations.

A.7 Marine Debris

Trash and debris released into the marine environment can harm marine mammals, turtles, and

birds through entanglement and ingestion.  Shell will adhere to the International Convention for

the Prevention of Pollution from Ships (MARPOL 73/78) Annex V requirements, USEPA and

USCG regulations, and MMS regulations and NTLs regarding solid wastes.  The BOEMRE

regulations at 30 CFR 250.300(a) and (b)(6) prohibit operators from deliberately discharging
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Environmental Impact Analysis for Initial EP Page 13

containers and other similar materials (e.g., trash and debris) into the marine environment, and

30 CFR 250.300(c) requires durable identification markings on equipment, tools and containers

(especially drums), and other material.  USCG and USEPA regulations require operators to

become proactive in avoiding accidental loss of solid waste items by developing waste

management plans, posting informational placards, manifesting trash sent to shore, and using

special precautions such as covering outside trash bins to prevent accidental loss of solid waste.  

Shell complies with NTL 2007‐G03, which instructs operators to exercise caution in the handling

and disposal of small items and packaging materials, requires the posting of placards at

prominent locations on offshore vessels and structures, and mandates a yearly marine trash and

debris awareness training and certification process.  Shell’s compliance with all applicable laws,

regulations, and NTL 2007‐G03 will avoid significant impacts on the environment.

A.8 Support Vessel and Helicopter Traffic

Shell will use existing shorebased facilities at Port Fourchon and Boothville, Louisiana, for onshore

support for water and air transportation, respectively.  No terminal expansion or construction is

planned at either location.

The supply base at Port Fourchon is operated by Shell and located on Bayou LaFourche,

approximately 3 miles (5 km) from the Gulf of Mexico.  During drilling, the project will be

supported by two crew boats and four offshore support vessels; a remotely operated vehicle

(ROV) assist vessel and Frac boat will be present to provide additional support during

completion of wells.  Crew boats will make two round‐trips per week between the drilling facility

and the onshore supply base, while at least one support vessel will be in the field at all times.  

The boats will normally move to the project area via the most direct route from the shorebase.   

The air transportation base will be the PHI Heliport in Boothville, Louisiana.  A helicopter will make

one round‐trip daily between the drilling rig or drillship and the heliport.  The helicopter will be

used to transport personnel and small supplies and will normally take the most direct route of

travel between the helicopter base and the lease area when air traffic and weather conditions

permit.  Helicopters typically maintain a minimum altitude of 213 m (700 ft) while in transit

offshore, 305 m (1,000 ft) over unpopulated areas or across coastlines, and 610 m (2,000 ft)

over populated areas and sensitive habitats such as wildlife refuges and park properties.

A.9 Accidents

A.9.1 Types of Accidents Evaluated

The analysis in this EIA focuses on two potential accidents:

• A small fuel spill, which is the most likely type of spill during OCS development activities; and

• The WCD for this Initial EP is an oil spill resulting from an uncontrolled blowout.  A blowout

resulting in a WCD 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

Initial EP Section 2j.  In accordance with NTL 2010‐N06, the estimated rate is 449,000

barrels for the first day with a 30‐day average of 359,000 BPD.  The estimated time to drill a

relief well is 150 days, and the total volume of a spill over this duration would be 25.9

million barrels of oil (MMBO).
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Environmental Impact Analysis for Initial EP Page 14

The following subsections summarize assumptions about the sizes and fates of these spills, as

well as Shell’s spill response plans.  Impacts are analyzed in Section C.

The lease sale EIS (MMS, 2007b) analyzes three other types of accidents: chemical spills, vessel

collisions, and loss of well control.  These accidents are discussed briefly in Section A.9.4.

A.9.2 Small Fuel Spill

Spill Size.  According to the analysis in MMS (2007b), the most likely type of small spill

(<1,000 bbl) as a result of OCS activities is a minor diesel fuel spill.  Historically, most diesel spills

have been <1 bbl, and this size is predicted to be the most common in ongoing and future

OCS activities in the Western and Central Gulf of Mexico Planning Areas (MMS, 2007b).  The

average size for spills <1 bbl is 0.07 bbl, and the median size for spills of 1 to 10 bbl is 3 bbl

(MMS, 2007b).  For this analysis, a small diesel fuel spill of 3 bbl is assumed.  Operational

experience suggests that the most likely cause of such a spill would be a hose rupture resulting

in the loss of the contents of a fuel transfer hose, which is less than 3 bbl.

Spill Fate.  The fate of a small fuel spill in the lease area would depend on meteorological and

oceanographic conditions at the time, as well as the effectiveness of spill response activities.  

However, given the open ocean location of the lease area, the duration of a small spill and the

opportunity for impacts to occur would be very brief.

The water‐soluble fractions of diesel are dominated by two‐ and three‐ringed polycyclic

aromatic hydrocarbons (PAHs), which are moderately volatile (National Research Council [NRC],

2003).  The constituents of these oils are light to intermediate in molecular weight and can be

readily degraded by aerobic microbial oxidation.  Diesel is so light that it will not sink to the

seafloor.  Diesel dispersed in the water column can adhere to suspended sediments, but this

generally occurs only in coastal areas with high suspended solids loads (NRC, 2003) and would

not be expected to occur to any appreciable degree in offshore waters of the Gulf of Mexico.  

Diesel oil is readily and completely degraded by naturally occurring microbes (NOAA, 2006).

The fate of a small diesel fuel spill was estimated using NOAA’s ADIOS2 (Automated Data Inquiry

for Oil Spills) model.  This model uses the physical properties of oils in its database to predict the

rate of evaporation and dispersion over time, as well as changes in the density, viscosity, and

water content of the product spilled.  It is estimated that over 90% of a small diesel spill would

be evaporated or dispersed within 24 hours.  The area of the sea surface with diesel fuel on it

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

The ADIOS2 results, coupled with spill trajectory information discussed below for a large spill,

indicate that a small fuel spill would not have any impacts on coastal or shoreline resources.  

The lease area is 51 miles (82 km) from the nearest shoreline (Louisiana).  Modeling results

discussed below indicate that a spill in the lease area would have a 4% probability of contacting

the nearest Louisiana shoreline (Plaquemines Parish) within 10 days after a spill.  By this time,

essentially 100% of a small fuel spill would have been dispersed or evaporated by natural

processes, even if no response measures were implemented.  MMS (2007b) similarly concluded

that spills <1,000 bbl are not expected to persist as a slick on the surface of the water beyond a

few days and are unlikely to make landfall or reach coastal waters prior to breaking up.  MMS

(2007b) noted that this conclusion is supported by a previous analysis of 3‐day trajectory model

runs, previous weathering analyses, and historical records of spill incidents.
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Spill Response.  In the unlikely event the shipboard prevention procedures fail to prevent a fuel

spill, response equipment and trained personnel would be available to ensure that any spill

effects are localized and would result only in short‐term environmental consequences.  

Initial EP Section 9b provides a detailed discussion of Shell’s response to a spill.

A.9.3 Crude Oil Spill (Worst Case Discharge)

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

Initial EP Section 2j.  Blowouts are rare events and most do not result in oil spills.  Holand (1997)

estimated a probability of 0.00142 for a blowout during development drilling based on U.S. Gulf

of Mexico data.  An updated analysis using the SINTEF database estimates a blowout frequency

of 0.00035 per development well for non‐North Sea locations (International Association of Oil &

Gas Producers, 2010).  As noted by MMS (2007b), from 1992 to 2005, half of blowouts lasted

less than half a day, and fewer than 10% of blowouts resulted in spilled oil.

The risk of a blowout during this project is significantly lower than indicated by these statistics

because the well design and drilling program were developed using information gathered during

the drilling of the previous wells in MC 762.  During drilling of the previous wells, the reservoirs

were fully logged and evaluated.  Substantial data associated with the reservoirs were gathered,

including but not limited to core, pressure, and fluid data.  Data gained during these earlier

operations provide substantial information that was used in preparing for the proposed

operation.

Spill Size.  In accordance with requirements of NTL 2010‐N06, Shell has estimated a WCD for this

Initial EP as 449,000 BPD for the first day with a 30‐day average of 359,000 BPD.  The estimated

time to drill a relief well is 150 days, and the total volume of a spill over this duration would be

25.9 MMBO.  The detailed analysis of this calculation can be found in Initial EP Section 2j.

Shell has a robust system in place to prevent blowouts.  Included in Initial EP  Sections 2j and 9b

is Shell’s response to NTL 2010‐N06, which includes descriptions of measures to prevent a

blowout, reduce the likelihood of a blowout, and conduct effective and early intervention in the

event of a blowout.  Shell will also comply with NTL 2010‐N10 and the Interim Final Drilling

Safety Rule, which specify additional safety measures for OCS activities.

Spill Trajectory.  The fate of a large oil spill in the lease area would depend on meteorological

and oceanographic conditions at the time.  The Oil Spill Risk Analysis (OSRA) model is a

computer simulation of oil spill transport that uses realistic data for winds and currents to

predict spill fate.  The OSRA report by Ji et al. (2004) provides conditional contact probabilities

for shoreline segments.  The results for Launch Area 58 (where MC 762 is located) are presented

in Table 3.  The model predicts no shoreline contacts within 3 days.  After 10 days, three

Louisiana parishes may be contacted.  After 30 days, 11 counties and parishes from Texas to the

Florida Panhandle may be contacted.  Plaquemines Parish, Louisiana, has the greatest

probability of shoreline contact, with a 4% and 8% chance within 10 and 30 days, respectively.
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Table 3. Conditional probabilities of a spill in the lease area contacting shoreline segments

(From: Ji et al., 2004).  Values are conditional probabilities that a hypothetical spill in

the lease area (represented by Oil Spill Risk Analysis Launch Area 58) could contact

shoreline segments within 3, 10, or 30 days.

Shoreline 

Segment County or Parish and State Conditional Probability of Contacta (%)

3 Days 10 Days 30 Days

C10 Galveston, TX -- -- 1

C12 Jefferson, TX -- -- 1

C13 Cameron, LA -- -- 3

C14 Vermilion, LA -- -- 2

C15 Iberia, LA -- -- 1

C17 Terrebonne, LA -- 1 3

C18 Lafourche, LA -- 2 3

C19 Jefferson, LA -- -- 1

C20 Plaquemines, LA -- 4 8

C21 St. Bernard, LA -- -- 1

C28 Okaloosa, FL -- -- 1

a Conditional probability refers to the probability of contact within the stated time period, assuming that a spill has

occurred (‐‐ indicates less than 0.5%).

The OSRA model does not evaluate the fate of a spill over time periods longer than 30 days, nor

does it predict the fate of a release that continues over a period of weeks or months.  Also as

noted by Ji et al. (2004), the OSRA model does not take into account the chemical composition

or biological weathering of oil spills, the spreading and splitting of oil spills, or spill response

activities.  The model does not assume a particular spill size but has generally been used by the

BOEMRE 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 particulate matter, and stranding on shore or

sedimentation to the seafloor (NRC, 2003).

Weathering decreases the concentration of oil and produces changes in its chemical

composition, physical properties, and toxicity.  The more toxic, light aromatic and aliphatic

hydrocarbons are lost rapidly by evaporation and dissolution from the slick on the water

surface.  Evaporated hydrocarbons are degraded rapidly by sunlight.  Biodegradation of oil on

the water surface and in the water column by marine bacteria removes first the n‐alkanes and

then the light aromatics from the oil.  Other petroleum components are biodegraded more

slowly.  Photooxidation attacks mainly the medium and high molecular weight PAHs in the oil on

the water surface.  

Spill Response.  Shell is a founding member of the Marine Well Containment Company (MWCC)

and has access to an integrated subsea well control and containment system that can be rapidly

deployed through the MWCC.  The MWCC is a non‐profit organization that manages and

provides fully trained crews and operates the subsea containment system during a response.  

The near‐term containment response capability will be specifically addressed in Shell’s

NTL 2010‐N10 submission at the time an Application to Drill (APD) is submitted and will include
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Environmental Impact Analysis for Initial EP Page 17

equipment and services available to Shell through MWCC’s development of near‐term capability

and other industry sources.  Shell is a member of Clean Caribbean & Americas (CCA), Marine

Spill Response Corporation (MSRC), Clean Gulf Associates (CGA), and Oil Spill Response Limited

(OSRL), organizations that are committed to providing the resources necessary to respond to a

spill as outlined in our Regional Oil Spill Response Plan (OSRP, October 2010).

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

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

government are better equipped and prepared today to contain an oil well blowout in

deepwater (see page 17 of the Decision Memorandum dated October 1, 2010 [Bromwich,

2010]).  Shell is further analyzing these advances and incorporating them into its comprehensive

approach to help prevent and, if needed, control another deepwater control incident.  Shell is

also investing in research and development to improve containment systems.  

The primary offshore response would involve mechanical recovery.  The primary response

equipment that would be mobilized to the spill location for spills in normal and adverse weather

conditions is included in the Offshore On‐Water Recovery Activation List in the OSRP.

Chemical dispersion capabilities are also readily available from resources such as MSRC at

Stennis, Mississippi, and Coolidge, Arizona; CGA/Airborne Support, Inc. (ASI) in Houma,

Louisiana; Oil Spill Response in South Hampton, UK and Singapore; and CCA in Ft. Lauderdale,

Florida.  Available equipment for surface and subsea application of dispersants, response times,

and support resources are identified in the OSRP.

Open‐water in‐situ burning (ISB) 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 ISB task forces could be deployed offshore.

See Initial EP Sections 2j and 9b for a detailed description of Shell’s site‐specific response to the

worst case spill for this plan.  These sections, along with Shell’s OSRP, also include a description

of surface and subsea containment capabilities that could be implemented in the event of the

worst case spill at this site.

A.9.4 Other Accidents Not Analyzed in Detail

The lease sale EIS (MMS, 2007b) discusses three other types of accidents: chemical spills, vessel

collisions, and loss of well control.  These accidents are discussed briefly below. No hydrogen

sulfide (H2S) occurs at this site, and no other site‐specific issues have been identified for this

Initial EP.  The analysis in the lease sale EIS for these topics is incorporated by reference.

Chemical Spill.  Chemicals are used in drilling operations to achieve technical goals in the drilling

process, improve the efficiency and safety of drilling, and protect associated equipment.  

Chemicals used during exploration and drilling include surfactants, bentonite clays, olefins,

inorganic salts, glycols, polymers, barite, and calcium carbonate.  Supplies are renewed on a

regular basis by transfer in containers from supply boats (Boehm et al., 2001).  In addition to

chemicals used in drilling fluids, the following chemicals are likely to be used on the drilling rig or

drillship: ethylene glycol (blowout prevention control fluid, 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),
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Environmental Impact Analysis for Initial EP Page 18

lubricating oil and grease (used in reciprocating and electrical equipment), and sodium

hypochlorite (dilute, used as laundry bleach and disinfectant).

A study of environmental risks of chemical products used in OCS activities determined that only

two chemicals could potentially affect the marine environment: zinc bromide and ammonium

chloride (Boehm et al., 2001).  The risk of a spill for these chemicals is very low.  Most other

chemicals are either nontoxic or used in small quantities.  No significant impacts are expected

from chemical spills.

Vessel Collisions.  As summarized in MMS (2007b), vessel collisions occasionally occur during

routine operations.  Most collision mishaps are the result of service vessels colliding with

platforms or vessel collisions with pipeline risers.  Some of these collisions have caused spills of

diesel fuel or chemicals.  Shell will comply with all USCG and BOEMRE‐mandated safety

requirements to minimize the potential for vessel collisions.

Loss of Well Control.  A loss of well control is the uncontrolled flow of a reservoir fluid that may

result in the release of gas, condensate, oil, drilling fluids, sand, or water.  Loss of well control is

a broad term that includes minor to serious well control incidents, while blowouts are

considered to be a subset of more serious incidents with greater risk of oil spill or human injury

(MMS, 2007b).  Loss of well control may result in the release of synthetic drilling fluid or loss of

oil.  Shell has a robust system in place to prevent loss of well control.  Included in this Initial EP is

Shell’s response to NTL 2010‐N06, which includes descriptions of measures to prevent a

blowout, reduce the likelihood of a blowout, and conduct effective and early intervention in the

event of a blowout.  Shell will also comply with NTL 2010‐N10 and the Interim Final Drilling

Safety Rule, which specify additional safety measures for OCS activities.  See

Initial EP Sections 2j and 9b for further information.

H2S Release.  Based on CFR 250.417(c), Shell requests that the Regional Supervisor, Field

Operations, classify the area in the proposed drilling operations as an area where the absence of

H2S has been confirmed.

B.  Affected Environment

The lease area is in the north‐central Gulf of Mexico, 51 miles (82 km) from the nearest

shoreline, 100 miles (161 km) from the onshore support base at Port Fourchon, Louisiana, and

77 miles (124 km) from the helicopter base at Boothville, Louisiana (Figure 1).

The wellsites are in an area of level seafloor with water depths ranging from 957 to 961 m

(3,140 to 3,152 ft) (Figure 2).  The side scan sonar survey confirmed the existence of man‐made

infrastructure including two wells, three pipelines, and two umbilicals in the project area

(C&C Technologies, Inc., 2008).  There will be no interferences with this infrastructure from the

proposed development drilling activity.  The new wells will be positioned more than 518 m

(1,700 ft) east of ATP Oil and Gas Corporation’s flowline and 1,052 m (3,450 ft) north of Shell’s

Europa (MC 935) to Mars (MC 807) flowlines.  

Seafloor gradients in the study area range from nearly flat to 19°.  The average gradient is

approximately 1.6°.  The highest seafloor gradients are associated with the seafloor fault

escarpments in the southeast quadrant of the study area (Geoscience Earth and Marine
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Environmental Impact Analysis for Initial EP Page 19

Services, Inc. [GEMS], 2003).  Based on a high‐resolution geophysical survey, consisting of

frequency enhanced 3‐D seismic, enhanced surface renderings (ESR), ESRs with amplitudes

applied, and autonomous underwater vehicle high‐resolution data, the geohazards assessment

concluded that MC 762 proposed locations M, N, O, P, Q, R, S, and T appear suitable for the

planned activity.

A detailed description of the regional affected environment is provided in recent EISs

(MMS, 2007b, 2008), including meteorology, oceanography, geology, air and water quality,

benthic communities, threatened and endangered species, biologically sensitive resources,

archaeological resources, socioeconomic conditions, and other marine uses.  These regional

descriptions are based on extensive literature reviews and are incorporated by reference.  

General background information is presented below, and brief descriptions of each potentially

affected resource are presented in Section C, including site‐specific and/or new information if

available.

The local environment in the lease area is not known to be unique with respect to

physical/chemical, biological, or socioeconomic conditions.  Baseline environmental conditions

in the lease area are expected to be consistent with the regional description of continental slope

locations evaluated in recent lease sale EISs (MMS, 2007b, 2008).

The lease area is approximately 65 miles (104 km) southwest of the Macondo spill site.  Based

on an analysis of satellite imagery (ESRI, 2010), the surface slick extended over the lease area at

various times prior to capping of the well; therefore, existing water quality in the lease area

could have been temporarily affected.  Macondo spill impacts are addressed in Section C.9

(Cumulative Impacts) where available and applicable.
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Environmental Impact Analysis for Initial EP Page 20

Figure 2. Bathymetric map of the lease area showing proposed well surface locations.
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Environmental Impact Analysis for Initial EP Page 21

C.  Impact Analysis

This section analyses the potential direct and indirect impacts of routine activities and accidents.  

Cumulative impacts are discussed in Section C.9.

Impacts have been analyzed extensively in recent multi‐lease‐sale EISs for the Western and

Central Gulf of Mexico Planning Areas (MMS, 2007b, 2008) as well as the EA for Gulf of Mexico

deepwater operations and activities (MMS, 2000) and a Grid EA for the Medusa Development in

MC 538 and 582 (MMS, 2002).  Site‐specific issues are addressed in this section as appropriate.

C.1 Physical/Chemical Environment

C.1.1 Air Quality

There are no site‐specific air quality data for the project area.  Due to the distance from

shorebased pollution sources, offshore air quality is expected to be good.  The attainment status

of Federal OCS waters is unclassified because there is no provision in the Clean Air Act for

classification of areas outside State waters (MMS, 2007b).

As of February 2011, all 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, 2011).  Three metropolitan areas in Texas are nonattainment areas for 8‐h

ozone (Beaumont‐Port Arthur, Dallas‐Fort Worth, and Houston‐Brazoria), and El Paso County is

a nonattainment area for PM‐10 (USEPA, 2011).

Winds in the region are driven by the clockwise circulation around the Bermuda High

(MMS, 2007b).  The Gulf of Mexico is located to the southwest of this center of circulation,

resulting in a prevailing southeasterly to southerly flow, which is conducive to transporting

emissions toward shore.  However, circulation is also affected by tropical cyclones (hurricanes)

during summer and fall, and by extratropical cyclones (cold fronts) during winter.

IPFs potentially affecting air quality are air pollutant emissions and two types of accidents:

a small fuel spill and a large oil spill (WCD).

Impacts of Air Pollutant Emissions

Air pollutant emissions are the only routine IPF likely to affect air quality.  Offshore air pollutant

emissions will result from the operation of the drilling rig or drillship, as well as helicopters and

service vessels.  These emissions occur mainly from combustion or burning of diesel fuel.  The

combustion of fuels occurs primarily on diesel‐powered generators, pumps, or motors and from

lighter fuel motors.  Primary air pollutants typically associated with OCS activities are suspended

PM, SOx, NOx, VOCs, and CO.

Due to the distance from shore, routine operations in the project area are not expected to have

any impact on air quality conditions along the coast, including nonattainment areas.  As noted in

the lease sale EIS (MMS, 2007b), emissions of air pollutants from routine activities in the Central

Gulf of Mexico Planning Area are projected to have minimal impacts to onshore air quality

because of the prevailing atmospheric conditions, emission heights, emission rates, and the

distance of these emissions from the coastline.  The Air Quality Emissions Report (see

Initial EP Section 8) prepared in accordance with BOEMRE requirements shows that the
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Environmental Impact Analysis for Initial EP Page 22

projected emissions for PM, SOx, NOx, VOCs, and CO are below exemption levels; therefore,

according to 30 CFR 250.303, the emissions will not significantly affect the air quality of the

onshore area for any of the criteria pollutants.  No further analysis is required. See Section A.3

for details of emission reduction controls and emission factor usage.  

The Breton Wilderness Area, which is part of the Breton National Wildlife Refuge (NWR), is

designated under the Clean Air Act as a Prevention of Significant Deterioration (PSD) Class I air

quality area.  The BOEMRE is required to notify the National Park Service (NPS) and the USFWS if

emissions from proposed projects may affect the Breton Class I area.  Additional review and

mitigation measures may be required for sources within 186 miles (300 km) of the Breton Class I

area that exceed emission limits agreed upon by the administering agencies (NPS, 2010).  The

lease area is approximately 87 miles (140 km) from the Breton Wilderness Area.  Shell does not

anticipate any impact on the Class I area but will comply with any emissions requirements as

directed by the BOEMRE.

Impacts of a Small Fuel Spill

Potential impacts of a small spill on air quality are expected to be consistent with those analyzed

and discussed in recent EISs (MMS, 2007b, 2008).  The probability of a small spill would be

minimized by Shell’s preventative measures during routine operations, including fuel transfer.  

In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce the

impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Given the open

ocean location of the lease area, the extent and duration of air quality impacts from a small spill

would not be significant.

A small fuel spill would affect air quality near the spill site by introducing VOCs through

evaporation.  The ADIOS2 model (see Section A.9.2) indicates that more than 90% of a small

diesel spill would be evaporated or dispersed within 24 hours.  The area of the sea surface with

diesel fuel on it would range from 0.5 to 5 ha (1.2 to 12 ac) depending on sea state and weather

conditions.

A small fuel spill would not affect coastal air quality because the spill would not be expected to

make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential impacts of a large oil spill on air quality are expected to be consistent with those

analyzed and discussed in recent EISs (MMS, 2007b, 2008).  

A large oil spill (WCD) would affect air quality by introducing VOCs through evaporation from the

slick.  The extent and persistence of impacts would depend on the meteorological and

oceanographic conditions at the time and the effectiveness of spill response measures.  

Additional air quality impacts could occur if response measures included ISB 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 (51 miles [82 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
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Environmental Impact Analysis for Initial EP Page 23

modeling predictions (Table 3), Plaquemines Parish, Louisiana, is the coastal area most likely to

be affected.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on air quality are expected.

C.1.2 Water Quality

There are no site‐specific water quality data for the lease area.  Due to the lease location in

deep, offshore waters, water quality is expected to be good, with low levels of contaminants.  As

noted in the lease sale EIS (MMS, 2007b), deepwater areas in the northern Gulf of Mexico are

relatively homogeneous with respect to temperature, salinity, and oxygen.  Kennicutt (2000)

noted that the deepwater region has little evidence of contaminants in the dissolved or

particulate phases of the water column.  However, there are localized occurrences of natural

seepage of oil, gas, and brines in near‐surface sediments and up through the water column.

The lease area is approximately 65 miles (104 km) southwest of the Macondo spill site.  Based

on satellite imagery (ESRI, 2010), the surface slick extended over the lease area during the spill,

and therefore existing water quality in the lease area could have been temporarily affected.  The

Operational Science Advisory Team (OSAT, 2010) reported that after August 2010, waters and

sediments in the deepwater Gulf of Mexico beyond 1.8 miles (3 km) from the Macondo wellsite

were below USEPA acute and chronic benchmarks for PAHs and were not hypoxic.  These

observations indicate that baseline environmental conditions in the lease area are unlikely to

have been significantly altered by the spill.

IPFs potentially affecting water quality are effluent discharges and two types of accidents:

a small fuel spill and a large oil spill (WCD).

Impacts of Effluent Discharges

Discharges of treated SBM cuttings will produce temporary, localized increases in suspended

solids in the water column around the drilling rig or drillship.  In general, turbid water can be

expected to extend between a few hundred meters and several kilometers down current from

the discharge point (NRC, 1983; Neff, 1987).  All NPDES permit limitations and requirements will

be met.  After discharge, SBM retained on cuttings would be expected to adhere tightly to the

cuttings particles and, consequently, would not produce much turbidity as the cuttings sink

through the water column (Neff et al., 2000).  There will be no persistent impacts on water

quality in the lease area.

Treated sanitary and domestic wastes may have a slight transient effect on water quality in the

immediate vicinity of these discharges.  All NPDES permit limitations and requirements will be

met and little or no impact on water quality is anticipated.

Deck drainage includes all effluents resulting from rain, deck washings, and runoff from curbs,

gutters, and drains, including drip pans in work areas.  Rainwater that falls on uncontaminated

areas of the drilling rig or drillship will flow overboard without treatment.  However, rainwater

that falls on the drilling rig or drillship deck and other areas such as chemical storage areas and
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Environmental Impact Analysis for Initial EP Page 24

places where equipment is exposed will be collected and oil and water separated to meet

NPDES permit requirements.  Little or no impact on water quality is anticipated.

Other discharges in accordance with the NPDES permit, such as desalination unit brine and

uncontaminated cooling water, fire water, and ballast water are expected to be diluted rapidly

and have little or no impact on water quality.

Support vessels will discharge treated sanitary and domestic wastes.  These will have a slight

effect on water quality in the immediate vicinity of the discharges.  All support vessel discharges

will be in accordance with USCG regulations and, as applicable, the NPDES Vessel General

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

Impacts of a Small Fuel Spill

Potential impacts of a small spill on water quality are expected to be consistent with those

analyzed and discussed in recent EISs (MMS, 2007b, 2008).  The probability of a small spill would

be minimized by Shell’s preventative measures during routine operations, including fuel

transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Given the

open ocean location of the lease area, the extent and duration of water quality impacts from a

small spill would not be significant.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  However, it is estimated that more

than 90% of a small diesel spill would be evaporated or dispersed within 24 hours (see

Section A.9.2).  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac) depending on sea state and weather conditions.

The water‐soluble fractions of diesel are dominated by two‐ and three‐ringed PAHs, which are

moderately volatile (NRC, 2003).  The constituents of these oils are light to intermediate in

molecular weight and can be readily degraded by aerobic microbial oxidation.  Diesel is so light

that it is not possible for the oil to sink and pool on the seafloor.  Diesel dispersed in the water

column can adhere to suspended sediments, but this generally occurs only in coastal areas with

high suspended solid loads (NRC, 2003) and would not be expected to occur to any appreciable

degree in offshore waters of the Gulf of Mexico.  Diesel oil is readily and completely degraded

by naturally occurring microbes (NOAA, 2006).

A small fuel spill would not affect coastal water quality because the spill would not be expected

to make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential impacts of a large oil spill on water quality are expected to be consistent with those

analyzed and discussed in recent EISs (MMS, 2007b, 2008).  A large spill would affect water

quality by producing a slick on the water surface and increasing the concentrations of petroleum

hydrocarbons and their degradation products.  The extent and persistence of impacts would

depend on the meteorological and oceanographic conditions at the time and the effectiveness

of spill response measures.  Most of the oil would be expected to form a slick at the surface,
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Environmental Impact Analysis for Initial EP Page 25

although new information from the Macondo spill indicates that plumes of submerged oil

droplets can be produced when subsea dispersants are applied at the wellhead (Camilli et al.,

2010; Hazen et al., 2010; Joint Analysis Group, 2010a,b,c).  A report by Kujawinski et al. (2011)

indicates that chemical components of subsea dispersants used during the Macondo spill

persisted for up to two months and were detectable up to 186 miles (300 km) from the wellsite

at a water depth of 1,000 to 1,200 m (3,280 to 3,937 ft).   

Once oil enters the ocean, a variety of physical, chemical, and biological processes acts to

disperse the oil slick.  These processes include spreading, evaporation of the more volatile

constituents, dissolution into the water column, emulsification of small droplets, agglomeration

sinking, microbial modification, photochemical modification, and biological ingestion and

excretion (NRC, 2003).  Marine water quality would be temporarily affected by the dissolved

components and small oil droplets that do not rise to the surface or are mixed down by surface

turbulence.  Dispersion by currents and microbial degradation removes the oil from the water

column or dilutes the constituents to background levels.

A large oil spill could result in a release of gaseous hydrocarbons that could affect water quality.  

During the Macondo spill, large volumes of methane (CH4) were released, causing localized

oxygen depletion as methanotrophic bacteria rapidly metabolized the hydrocarbons (Joye et al.,

2011; Kessler et al., 2011).  However, a broader study of the deepwater Gulf of Mexico found

that although some stations showed had a slight depression of dissolved oxygen relative to

climatological background values, the findings were not indicative of hypoxia (OSAT, 2010).  

Stations revisited around the Macondo wellhead in October 2010 showed no measurable

oxygen depressions (OSAT, 2010).

Due to the lease area location (51 miles [82 km] from the nearest shoreline), most water quality

impacts would occur in offshore waters.  Depending on the spill trajectory and the effectiveness

of spill response measures, coastal water quality could be affected.  Based on the OSRA

modeling predictions (Table 3), nearshore waters and embayments of Plaquemines Parish,

Louisiana, are the most likely coastal areas where water quality could be affected.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on water quality are expected.

C.2 Seafloor Habitats and Biota

Water depths at the proposed well surface locations range from 957 to 961 m (3,140 to

3,152 ft).  The seafloor is expected to consist mainly of soft bottom.  The chemosynthetic

community assessment based on the hazards report by GEMS (2003) did not identify any

features that could support high‐density deepwater benthic communities within 610 m

(2,000 ft) of the wellsites.  See Initial EP Section 6a for further information.

According to the BOEMRE (2011), existing information for the deepwater Gulf of Mexico

indicates that the seafloor is composed primarily of soft sediments; hard bottom communities

are rare.  MC 762 is within deepwater Grid 12, and the BOEMRE website indicates that ROV

coverage of the seafloor in this grid is adequate to characterize the area.
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C.2.1 Soft Bottom Benthic Communities

Data from the recent Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology

study (Wei, 2006; Rowe and Kennicutt, 2009) can be used to describe typical benthic

communities in the area.  Table 4 summarizes data from two nearby stations in similar water

depths.  Sediments at these two stations were predominantly clay (46% to 54%) and silt

(43% to 45%).

Table 4. Benthic community data from stations near the lease area and in similar water depths

sampled during the Northern Gulf of Mexico Continental Slope Habitats and Benthic

Ecology Study (From: Wei, 2006; Rowe and Kennicutt, 2009).

Station 

Location 

Relative to 

Lease Area 

Water 

Depth 

(m) 

Abundance 

Meiofauna 

(individuals/m2) 

Macroinfauna 

(individuals/m2) 

Megafauna 

(individuals/ha) 

MT-3 15 mi NNE 987 885,995 4,924 1,034 

MT-4 21 mi SE 1,401 246,058 3,262 1,548 

Meiofaunal and megafaunal abundance from Rowe and Kennicutt (2009); macroinfaunal abundance from Wei

(2006).

Meiofauna (animals passing through a 0.5‐mm sieve but retained on a 0.062‐mm sieve)

densities in water depths representative of the lease area typically range from about 250,000 to

650,000 individuals/m2 (Rowe and Kennicutt, 2009).  Nematodes, nauplii, and harpacticoid

copepods were the three dominant groups in the meiofauna, accounting for about 90% of total

abundance.  

The benthic macroinfauna is characterized by small mean individual sizes and low densities,

both of which are a reflection of the meager primary production in Gulf of Mexico surface

waters (Wei, 2006).  Densities decrease exponentially with water depth.  Based on an equation

presented by Wei (2006), macroinfaunal densities in the water depths of the wellsites are

expected to be about to 3,239 individuals/m2

, lower than the values in Table 4.

Polychaetes are typically the most abundant macroinfaunal group on the northern Gulf of

Mexico continental slope, followed by amphipods, tanaids, bivalves, and isopods.  Wei (2006)

recognized four depth‐dependent faunal zones (1 through 4), two of which are divided

horizontally.  The lease area is in Zone 2E, which consists of stations on the mid Texas‐Louisiana

Slope ranging in depth from 625 to 1,828 m (2,050 to 5,997 ft).  The five most abundant species

in Zone 2E were the polychaetes Litocorsa antennata, Aricidea suecica, Tharyx marioni, and

Paralacydonia paradoxa and the bivalve Heterodonta sp.

Megafaunal density from nearby stations MT‐3 and MT‐4 was 1,034 and 1,548 individuals/ha,

respectively (Table 4).  Densities of 300 to 2,000 individuals/ha were reported from other

stations in a similar depth range.  Common megafauna included motile groups such as

decapods, ophiuroids, holothurians, and demersal fishes, as well as sessile groups such as

sponges and anemones.

Bacteria are also an important component in terms of biomass and cycling of organic carbon

(Cruz‐Kaegi, 1998).  Bacterial biomass at the depth range of the lease area typically is about 1 to

2 grams of carbon per square meter (g C/m2

) in the top 15 cm of sediments (Rowe and

Kennicutt, 2009).
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Environmental Impact Analysis for Initial EP Page 27

IPFs potentially affecting benthic communities are physical disturbance to the seafloor, effluent

discharges (drilling muds and cuttings), and a large oil spill (WCD) resulting from a well blowout

at the seafloor.  A small fuel spill would not affect benthic communities because the diesel fuel

would float and dissipate on the sea surface.

Impacts of Effluent Discharges

Drilling muds and cuttings are the only effluents that are likely to affect benthic communities.  

During initial well interval(s) before the marine riser is set, cuttings and seawater‐based “spud

mud” will be released at the seafloor.  Excess cement slurry will also be released at the seafloor

during casing installation for the riserless portion of the drilling operations.  Cement slurry

components typically include cement mix and some of the same chemicals used in water‐based

drilling muds (Boehm et al., 2001).  The main impacts will be burial and smothering of benthic

organisms within several meters to tens of meters around the wellbore.  Soft bottom sediments

disturbed by cuttings, drilling muds, and cement slurry will eventually be recolonized through

larval settlement and migration from adjacent areas.  Because some deep‐sea biota grow and

reproduce slowly, recovery may require several years.

Discharges of treated SBM cuttings from the rig may affect benthic communities, primarily

within several hundred meters of the wellsites.  The fate and effects of SBM cuttings have been

reviewed by Neff et al. (2000), and monitoring studies have been conducted in the Gulf of

Mexico by Continental Shelf Associates, Inc. (2004, 2006).  In general, cuttings with adhering

SBMs tend to clump together and form thick cuttings piles close to the drillsite.  Areas of SBM

cuttings deposition may develop elevated organic carbon concentrations and anoxic conditions

(Continental Shelf Associates, Inc., 2006).  Where SBM cuttings accumulate and concentrations

exceed approximately 1,000 mg/kg, benthic infaunal communities may be adversely affected

due to both the toxicity of the base fluid and organic enrichment (with resulting anoxia) (Neff et

al., 2000).  Infaunal numbers may increase and diversity may decrease as opportunistic species

that tolerate low oxygen and high H2S predominate (Continental Shelf Associates, Inc., 2006).  As

the base synthetic fluid is decomposed by microbes, the area will gradually return to pre‐drilling

conditions.  Disturbed sediments will be recolonized through larval settlement and migration

from adjacent areas.

The areal extent of impacts from drilling discharges will be small.  Assuming a typical effect

radius of 500 m (1,640 ft), the affected area around each wellsite would represent about 3% of

the seafloor within a lease block.  For the eight surface locations in this development drilling

program, the total impact area would be 628 ha (1,552 ac) or 27% of a lease block.  The actual

area will be somewhat less because of overlapping impact radii among the eight surface

locations that are associated with the eight proposed wells.  Soft bottom communities are

ubiquitous along the northern Gulf of Mexico continental slope (Gallaway, 1988; Gallaway et al.,

2003; Rowe and Kennicutt, 2009).  Impacts from drilling discharges during this project will have

no significant impact on soft bottom benthic communities on a regional basis.  This conclusion is

in accord with the findings of the EA for Grid 12 prepared by MMS (2002), which concluded that

development activities in this area would have minimal impacts on the ecological function,

biological productivity, or distribution of soft bottom communities.

Impacts of a Large Oil Spill (WCD)

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
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Environmental Impact Analysis for Initial EP Page 28

could resuspend and disperse sediments within a 300‐m (984‐ft) radius.  While coarse sediments

(sands) would probably settle at a rapid rate within 400 m (1,312 ft) from the blowout site, fine

sediments (silts and clays) could be resuspended for more than 30 days and dispersed over a

much wider area.  Previous studies characterized surface sediments in the vicinity of the site as

about 50% clay and 45% silt (Rowe and Kennicutt, 2009).  

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill

location.  However, during the Macondo spill, subsurface plumes were reported at a water

depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsites and

persisting for more than a month (Camilli et al., 2010).  The subsurface plumes apparently

resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c).  This

observation is supported by Kujawinski et al. (2011) in their report that chemical components of

subsea dispersants used during the Macondo spill persisted for up to two months and were

detected up to 186 miles (300 km) from the wellsite at a water depth of 1,000 to 1,200 m

(3,280 to 3,937 ft).  However, estimated dispersant concentrations in the subsea plume were

below levels known to be toxic to marine life.  While the behavior and impacts of subsurface

plumes are not well known, a subsurface plume could contact the seafloor and affect benthic

communities beyond the 300‐m (984‐ft) radius estimated by MMS (2007a, 2008), depending on

its extent, trajectory, and persistence.  This contact could result in smothering and/or toxicity to

benthic organisms.  The affected area would be recolonized by benthic organisms over a period

of months to years (NRC, 2003).

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on soft bottom communities are

expected.

C.2.2 High‐Density Deepwater Benthic Communities

As defined by NTL 2009‐G40, high‐density deepwater benthic communities are features or areas

that could support high‐density chemosynthetic communities, or features or areas that could

support high‐density deepwater corals and other associated high‐density hard bottom

communities.  Chemosynthetic communities were discovered in the central Gulf of Mexico in

1984 and have been studied extensively (MacDonald, 2002).  Deepwater coral communities are

also known from numerous locations in the Gulf of Mexico (Brooke and Schroeder, 2007;

CSA International, Inc., 2007).  These communities occur almost exclusively on authigenic

carbonates created by chemosynthetic communities.

The nearest known chemosynthetic community sites are located 43 miles (69 km)

west‐southwest of MC 762 in MC 658.  

The chemosynthetic community assessment included in this Initial EP, based on the shallow

hazards report by GEMS (2003), did not identify any features that could support high‐density

deepwater benthic communities within 610 m (2,000 ft) of the proposed drilling mud/cuttings

discharge locations.
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Environmental Impact Analysis for Initial EP Page 29

IPFs potentially affecting high‐density deepwater benthic communities are effluent discharges

(drilling muds and cuttings), and a large oil spill (WCD) from a well blowout at the seafloor.  

A small fuel spill would not affect benthic communities because the diesel fuel would float and

dissipate on the sea surface.  Because a dynamically positioned drillship will be used, there will

be no anchoring impacts.

Impacts of Effluent Discharges

The chemosynthetic community assessment included in this Initial EP, based on the shallow

hazards report by GEMS (2003), did not identify any features that could support high‐density

deepwater benthic communities within 610 m (2,000 ft) of the proposed drilling mud/cuttings

discharge locations.  Monitoring programs on the Gulf of Mexico continental slope have shown

that benthic impacts from drilling discharges typically are concentrated within about 500 m

(1,640 ft) of the wellsites, although detectable deposits may extend beyond this distance

(Continental Shelf Associates, Inc., 2004, 2006; Neff et al., 2005).  If high‐density deepwater

communities are associated with the more distant expulsion features and mud volcanoes

identified in the hazards survey, significant impacts on these communities will be avoided

because of the distance from the discharge location.

Impacts of a Large Oil Spill (WCD)

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill

location.  However, during the Macondo spill, subsurface plumes were reported at a water

depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsites and

persisting for more than a month (Camilli et al., 2010).  The subsurface plumes apparently

resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c).  This

observation is supported by Kujawinski et al. (2011) in their report that chemical components of

subsea dispersants used during the Macondo spill persisted for up to two months and were

detectable up to 186 miles (300 km) from the wellsite at a water depth of 1,000 to 1,200 m

(3,280 to 3,937 ft).  However, estimated dispersant concentrations in the subsea plume were

below levels known to be toxic to marine life.  While the behavior and impacts of subsurface

plumes are not well known, a subsurface plume could have the potential to contact high‐density

deepwater benthic communities beyond the 300‐m (984‐ft) radius estimated by MMS (2007a,

2008), depending on its extent, trajectory, and persistence.  Potential impacts on sensitive

resources would be an integral part of the decision and approval process for the use of

dispersants.

Potential impacts of oil on high‐density deepwater benthic communities are discussed by

MMS (2007b).  Although chemosynthetic communities live among hydrocarbon seeps, natural

seepage is very constant and occurs at low rates compared to the potential rates of oil release

from a blowout.  In addition, seep organisms also require unrestricted access to oxygenated

water at the same time as exposure to hydrocarbon energy sources (MacDonald, 2002).  Oil

droplets or oiled sediment particles could come into contact with chemosynthetic organisms or

deepwater corals.  As discussed by MMS (2007b), impacts could include loss of habitat,

biodiversity, and live coral coverage; destruction of hard substrate; change in sediment

characteristics; and reduction or loss of one or more commercial and recreational fishery
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Environmental Impact Analysis for Initial EP Page 30

habitats.  Sublethal effects could be long‐lasting and affect the resilience of coral colonies to

natural disturbances (e.g., elevated water temperature and diseases).

The potential for a spill to affect deepwater corals is indicated by preliminary findings from a

recent (October 2010) survey of deepwater coral habitats near the Macondo spill site

(BOEMRE, 2010).  Government and academic researchers were working at a site 1,400 m

(4,600 ft) deep and approximately 7 miles (11 km) southwest of the Macondo wellhead when

they visually observed dead and dying corals with sloughing tissue and discoloration.  The study

location was about 58 miles (93 km) from the lease area.  Much of the soft coral observed in an

area measuring about 15 to 40 m (50 to 130 ft) was covered by what appeared to be a brown

substance.  Ninety percent of 40 large corals were heavily affected and showed dead and dying

parts and discoloration.  Another site 400 m (1,312 ft) away had a colony of stony corals

similarly affected and partially covered with a similar brown substance.  Until laboratory

analyses are conducted, scientists cannot be certain what caused the impacts.  Sediment and

coral samples were collected with an ROV and brought to the surface for analyses.  Further

testing will also determine if the substance is oil, and if so, whether it is consistent with the

release from the Macondo spill.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on deepwater benthic communities

are expected.

C.2.3 Designated Topographic Features

The blocks are not within or near a designated topographic feature or a no‐activity zone as

identified in NTL 2009‐G39.  The nearest topographic feature is Sackett Bank, located 32 miles

(52 km)  northwest of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to designated topographic features due to the distance from the lease area.  A small

fuel spill would float and dissipate on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf edge.

C.2.4 Pinnacle Trend Area Live Bottoms

The lease area is not covered by the Live Bottom (Pinnacle Trend) Stipulation.  As defined by

NTL 2009‐G39, the nearest pinnacle trend blocks are about 85 miles (137 km) north from the

lease area, along the shelf edge south of Alabama.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to pinnacle trend area live bottoms due to the distance from the lease area.  A small

fuel spill would float on the surface and would not reach these seafloor features.
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In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf edge.

C.2.5 Eastern Gulf Live Bottoms

The lease area is not covered by the Live Bottom (Low‐Relief) Stipulation, which applies to

Eastern Gulf of Mexico Planning Area leases in water depths of 100 m (328 ft) or less.  The

nearest blocks covered by the live bottom stipulation, as defined by NTL 2009‐G39, are about

121 miles (195 km) north‐northeast from the project area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to eastern Gulf live bottom areas due to the distance from the lease area.  A small fuel

spill would float and dissipate on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf.

C.3 Threatened, Endangered, and Protected Species and Critical Habitat

This section discusses species listed as endangered or threatened under the ESA.  In addition, it

includes all marine mammal species in the region, which are protected under the MMPA.

Endangered or threatened species that may occur in the project area and/or along the northern

Gulf coast are listed in Table 5.  The table also indicates the location of critical habitat (if

designated in the Gulf of Mexico).  Critical habitat is defined as (1) specific areas within the

geographical area occupied by the species at the time of listing, if they contain physical or

biological features essential to conservation, and those features may require special

management considerations or protection; and (2) specific areas outside the geographical area

occupied by the species if the agency determines that the area itself is essential for

conservation.  The NMFS has jurisdiction over ESA‐listed cetaceans, sea turtles, and fishes in the

Gulf of Mexico.  The USFWS has jurisdiction over ESA‐listed birds and the Florida manatee.

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.
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Table 5. Federally‐listed endangered and threatened species in the lease area and along the

northern Gulf coast.

Species Scientific Name Status 

Potential 

Presence Critical Habitat 

Designated in 

Gulf of Mexico Lease 

Area Coastal 

Marine Mammals 

Sperm whale Physeter macrocephalus E X -- None

Florida manatee Trichechus manatus 

latirostris E -- X Florida 

(Peninsular)

Blue whale Balaenoptera musculus E Xa -- None

Fin whale Balaenoptera physalus E Xa -- None

Humpback whale Megaptera novaeangliae E Xa -- None

North Atlantic right whale Eubalaena glacialis E Xa -- None

Sei whale Balaenoptera borealis E Xa -- None

Sea Turtles 

Loggerhead turtle Caretta caretta T X X None

Green turtle Chelonia mydas T, Eb X X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempii E X X None

Birds 

Piping Plover Charadrius melodus T -- X 

Coastal Texas, 

Louisiana, Mississippi, 

Alabama, and Florida 

(Panhandle)

Whooping Crane Grus americana E -- X 

Coastal Texas 

(Aransas National 

Wildlife Refuge)

Fishes 

Gulf sturgeon Acipenser oxyrinchus 

desotoi T -- X 

Coastal Louisiana, 

Mississippi, Alabama, 

and Florida 

(Panhandle)

Terrestrial Mammals 

Beach mouse (Alabama, 

Choctawhatchee, 

Perdido Key, 

St. Andrew)

Peromyscus polionotus E -- X Alabama and Florida 

(Panhandle) beaches 

Abbreviations: E = endangered; T = threatened. a

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

unlikely to be present in the lease area. b

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

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare

or extralimital there (Würsig et al., 2000).  No critical habitat has been designated for these

species in the Gulf of Mexico.

Coastal endangered or threatened species include the Florida manatee, Piping Plover,

Whooping Crane, Gulf sturgeon, and four subspecies of beach mouse.  Critical habitat has been

designated for all of these species as indicated in Table 5 and discussed in individual sections.

Two other coastal species (Bald Eagle and Brown Pelican) discussed by MMS (2007b) are no

longer listed as endangered or threatened; these are discussed under Coastal and Marine Birds.

There are no other endangered animals or plants in the Gulf of Mexico that are reasonably likely

to be affected by either routine or accidental events.  Other species occurring at certain
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Environmental Impact Analysis for Initial EP Page 33

locations in the Gulf of Mexico such as the smalltooth sawfish (Pristis pectinata), elkhorn coral

(Acropora palmata), staghorn coral (Acropora cervicornis), and Florida salt marsh vole (Microtus

pennsylvanicus dukecampbelli) are remote from the lease area and highly unlikely to be

affected.

C.3.1 Sperm Whale (Endangered)

The only endangered marine mammal likely to be present at or near the project area is the

sperm whale (Physeter macrocephalus).  Resident populations of sperm whales occur within the

Gulf of Mexico.  A species description is presented in a recent lease sale EIS (MMS, 2007b).  Gulf

of Mexico sperm whales are classified as an endangered species and a “strategic stock” (defined

as a stock that may have unsustainable human‐caused impacts) by NMFS (Waring et al., 2009).  

No critical habitat for the sperm whale has been designated in the Gulf of Mexico.

The distribution of sperm whales in the Gulf of Mexico is correlated with mesoscale physical

features such as eddies associated with the Gulf of Mexico Loop Current (Jochens et al., 2008).  

Sperm whale populations in the north‐central Gulf of Mexico are present there throughout the

year (Davis et al., 2000).  Results of a multi‐year tracking study show female sperm whales

typically concentrated along the upper continental slope between the 200‐ and 1,000‐m

(656‐ and 3,280‐ft) depth contours (Jochens et al., 2008).  Male sperm whales were more

variable in their movements and were documented in water depths greater than 3,000 m

(9,843 ft).  Generally, groups of sperm whales sighted in the Gulf of Mexico during the

MMS‐funded Sperm Whale Seismic Study (SWSS) consisted of mixed‐sex groups comprising

adult females and immatures, and groups of bachelor males.  Typical group size for mixed

groups was 10 individuals (Jochens et al., 2008).  SWSS results show that sperm whales transit

through the vicinity of the lease area.  Movements of satellite‐tracked individuals suggest that

this area of the Gulf continental slope is within the home range of the Gulf of Mexico population

(within the 95% utilization distribution) (Jochens et al., 2008).

IPFs potentially affecting sperm whales include drilling rig and drillship presence, noise, and

lights; support vessel and helicopter traffic; and two types of accidents – a small fuel spill and a

large oil spill (WCD).  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 2007‐G03 will

minimize the potential for marine debris‐related impacts on sperm whales.

Impacts of Drilling Rig and Drillship Presence, Noise, and Lights

Noise from routine drilling activities has the potential to disturb sperm whales.  Sperm whales

appear to have good low‐frequency hearing, but the available data do not indicate a consistent

response to anthropogenic noise (Jochens et al., 2008).  Noise associated with drilling is

relatively weak in intensity, and an individual animal’s noise exposure would be transient.  There

are other OCS facilities and activities near the lease area, and the region as a whole has a large

number of similar sources.  Due to the limited scope and short duration of drilling activities, this

project would represent a small temporary contribution to the overall noise regime.

The NMFS (2007) analyzed the potential for impacts of drilling‐related noise on sperm whales in

its Biological Opinion for the Five‐Year Oil and Gas Leasing Program in the Central and Western

Planning Areas of the Gulf of Mexico.  The analysis noted that drilling rigs and drillships show

low sound source levels and concluded that drilling is not expected to produce amplitudes
Mississippi Canyon Blocks 762, 805, and 806 April 2011

Environmental Impact Analysis for Initial EP Page 34

sufficient to cause hearing or behavioral effects in sperm whales; therefore, these effects are

insignificant (NMFS, 2007).

Although drilling rig and drillship lighting and presence were considered potential factors

affecting sperm whales, NMFS’s 2007 Biological Opinion and recent lease sale EISs (MMS,

2007b, 2008) did not identify these as IPFs for sperm whales

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sperm whales, and there is also a risk of vessel

strikes, which are identified as a threat in the recovery plan for this species (NMFS, 2006).  Data

concerning the frequency of vessel strikes is presented in the lease sale EIS (MMS, 2007b).  To

reduce the potential for vessel strikes, the BOEMRE has issued NTL 2007‐G04, which

recommends protected species identification training and that vessel operators and crews

maintain a vigilant watch for marine mammals and slow down or stop their vessel to avoid

striking protected species, and requires operators to report sightings of any injured or dead

protected species.  When whales are sighted, vessel operators and crews are required to

attempt to maintain a distance of 91 m (300 ft) or greater whenever possible.  Vessel operators

are required to reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large

assemblages of cetaceans are observed near an underway vessel when safety permits.  

Compliance with this NTL will minimize the likelihood of vessel strikes as well as reduce the

chance for disturbing sperm whales.

The NMFS (2007) analyzed the potential for vessel strikes and harassment of sperm whales in its

Biological Opinion for the Five‐Year Oil and Gas Leasing Program in the Central and Western

Planning Areas of the Gulf of Mexico.  With implementation of the mitigation measures in

NTL 2007‐G04, NMFS concluded that the likelihood of collisions between vessels and sperm

whales would be reduced to insignificant levels.  The NMFS concluded that the observed

avoidance of passing vessels by sperm whales is an advantageous response to avoid a potential

threat and is not expected to result in any significant effect on migration, breathing, nursing,

breeding, feeding, or sheltering to individuals, or have any consequences at the level of the

population.  With implementation of the vessel strike avoidance measures requirement to

maintain a distance of 90 m (295 ft) from sperm whales, the NMFS concluded that the potential

for harassment of sperm whales would be reduced to discountable levels.

Helicopter traffic also has the potential to disturb sperm whales.  Smultea et al. (2008)

documented responses of sperm whales offshore Hawaii to fixed wing aircraft flying at an

altitude of 245 m (800 ft).  A reaction to the initial pass of the aircraft was observed during three

(12%) of 24 sightings.  All three reactions consisted of a hasty dive and occurred at less than

360 m (1,180 ft) lateral distance from the aircraft.  Additional reactions were seen when aircraft

circled certain whales to make further observations.  Based on other studies of cetacean

responses to sound, the authors concluded that the observed reactions to brief overflights by

the aircraft were short‐term and probably of no long‐term biological significance.

While flying offshore in the Gulf of Mexico, helicopters maintain altitudes above 213 m (700 ft)

during transit to and from the working area.  In the event that a whale is seen during transit, the

helicopter will not approach or circle the animals.  Although responses are possible based on the

Smultea et al. (2008) study, the NMFS (2007) concluded that this altitude would minimize the

potential for disturbing sperm whales.  Therefore, no significant impacts are expected.
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Environmental Impact Analysis for Initial EP Page 35

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals including sperm whales are discussed in recent EISs

(MMS, 2007b, 2008) and by the NMFS (2007) in its Biological Opinion for the Five‐Year Oil and

Gas Leasing Program in the Central and Western Planning Areas of the Gulf of Mexico.  Oil

impacts on marine mammals are discussed by Geraci and St. Aubin (1990).  For this Initial 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.  Initial EP Sections 2j

and 9b provide detail on spill response measures.  Given the open ocean location of the lease

area, the duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (Marine Mammal Commission [MMC], 2010).  However,

due to the limited areal extent and short duration of water quality impacts from a small fuel

spill, as well as the mobility of sperm whales, no significant impacts would be expected.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine mammals including sperm whales are discussed in recent EISs

(MMS, 2007b, 2008) and by the NMFS (2007) in its Biological Opinion for the Five‐Year Oil and

Gas Leasing Program in the Central and Western Planning Areas of the Gulf of Mexico.  Oil

impacts on marine mammals are discussed by Geraci and St. Aubin (1990).  For this Initial EP,

there are no unique site‐specific issues with respect to spill impacts on these animals.

Impacts of oil spills on sperm whales can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants) (MMC, 2010).  Direct physical and physiological effects can include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey; and stress from

the activities and noise of response vessels and aircraft.  Complications of the above may lead to

dysfunction of immune and reproductive systems, physiological stress, declining physical

condition, and death.  Behavioral responses can include displacement of animals from prime

habitat, disruption of social structure, changing prey availability and foraging distribution and/or

patterns, changing reproductive behavior/productivity, and changing movement patterns or

migration (MMC, 2010).
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Environmental Impact Analysis for Initial EP Page 36

Studies have shown that the cetacean epidermis functions as an effective barrier to noxious

substances found in petroleum (Geraci and St. Aubin, 1985).  Unlike other mammals,

penetration of such substances in cetacean skin is impeded by tight intercellular bridges, the

vitality of the superficial cells, the thickness of the epidermis, and the lack of sweat glands and

hair follicles.  In addition, cetacean skin is free from hair or fur, which in other marine mammals

not found in the Gulf of Mexico (e.g., pinnipeds and otters) tends to collect oil and/or tar.

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb sperm whales and potentially result in vessel strikes, entanglement, or other injury

or stress.  Response vessels would operate in accordance with NTL 2007‐G04 to reduce the

potential for striking or disturbing these animals.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on sperm whales are expected.

C.3.2 Florida Manatee (Endangered)

Most of the manatee population is located in peninsular Florida (USFWS, 2001).  Manatees

regularly migrate farther west of Florida in the warmer months (Wilson, 2003) into Alabama and

Louisiana coastal environs and with some individuals traveling as far as west Texas (Fertl et. al.,

2005).  A species description is presented in a recent lease sale EIS (MMS, 2007b) and in the

recovery plan for this species (USFWS, 2001).

IPFs potentially affecting manatees include support vessel and helicopter traffic and a large oil

spill (WCD).  A small fuel spill in the lease area would be unlikely to affect manatees, as the lease

area is approximately 51 miles (82 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 2007‐G03 will minimize the potential for marine

debris‐related impacts on manatees.

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb manatees, and there is also a risk of vessel

strikes, which are identified as a threat in the recovery plan for this species (USFWS, 2001).  To

reduce the potential for vessel strikes, the BOEMRE has issued NTL 2007‐G04, which

recommends protected species identification training and that vessel operators and crews

maintain a vigilant watch for marine mammals and slow down or stop their vessel to avoid

striking protected species, and requires operators to report sightings of any injured or dead

protected species.  Compliance with this NTL will minimize the likelihood of vessel strikes, and

no significant impacts on manatees are expected.

Helicopter traffic, if present, also has the potential to disturb manatees.  Rathbun (1988)

reported that manatees were disturbed more by helicopters than by fixed‐wing aircraft;

however, the helicopter was flown at a relatively low altitude of 20 to 160 m (66 to 525 ft).  

Helicopters used in support operations maintain a minimum altitude of 213 m (700 ft) while in

transit offshore, 305 m (1,000 ft) over unpopulated areas or across coastlines, and 610 m

(2,000 ft) over populated areas and sensitive habitats such as wildlife refuges and park
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Environmental Impact Analysis for Initial EP Page 37

properties.  This mitigation measure will minimize the potential for disturbing manatees, and no

significant impacts are expected.

Impacts of a Large Oil Spill (WCD)

The OSRA results summarized in Table 3 predict that some Texas, Louisiana, and Florida

shorelines could be contacted by a spill within 30 days.  There is no critical habitat designated in

these areas, and the number of manatees potentially present is a small fraction of the

population in peninsular Florida.

In the event that manatees were exposed to oil, effects could include direct impacts from oil

exposure, as well as indirect impacts due to response activities and materials (e.g., vessel traffic,

noise, and dispersants) (MMC, 2010).  Direct physical and physiological effects can include skin

irritation, inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes;

inhalation of toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey (or

contaminated vegetation, in the case of manatees); and stress from the activities and noise of

response vessels and aircraft.  Complications of the above may lead to dysfunction of immune

and reproductive systems, physiological stress, declining physical condition, and death.  

Behavioral responses can include displacement of animals from prime habitat, disruption of

social structure, changing prey availability and foraging distribution and/or patterns, changing

reproductive behavior/productivity, and changing movement patterns or migration

(MMC, 2010).

In the event that a large spill reached coastal waters where manatees were present, the level of

vessel and aircraft activity associated with spill response could disturb manatees and potentially

result in vessel strikes, entanglement, or other injury or stress.  Response vessels would operate

in accordance with NTL 2007‐G04 to reduce the potential for striking or disturbing these

animals, and therefore no significant impacts are expected.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on manatees are expected.

C.3.3 Endangered Mysticete Whales

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare

or extralimital there (Würsig et al., 2000).  No critical habitat has been designated for these

species in the Gulf of Mexico.   

Due to the rare occurrence of these whales in the Gulf of Mexico and the limited scope and

duration of the project, it is highly unlikely that any endangered mysticete would come into

contact with any project activities, either routine operations or accidents.  The NMFS (2007) did

not include any of these mysticete whales as affected species in its Biological Opinion for the

Five‐Year Oil and Gas Leasing Program in the Central and Western Planning Areas of the Gulf of

Mexico.  Potential impacts are analyzed in recent lease sale EISs (MMS, 2007b, 2008), and those

analyses are incorporated by reference.  If any of these whales were present in the area,

potential impacts would be the same as those discussed below in Section C.3.4.
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C.3.4 Non‐Endangered Marine Mammals (Protected)

Excluding the seven endangered species that have been cited previously, there are 22 additional

species of marine mammals that may be found in the Gulf of Mexico (see Initial EP Section 6h).  

All marine mammals are protected species under the MMPA.  This includes two mysticete

whales, the dwarf and pygmy sperm whales, 4 species of beaked whales, and 14 species of

delphinids.  The most common non‐endangered cetaceans in the deepwater environment are

odontocetes such as the pantropical spotted dolphin, spinner dolphin, and clymene dolphin.  A

brief summary is presented below, and additional information on these groups is presented in a

recent lease sale EIS (MMS, 2007b).

Mysticete whales.  Two non‐endangered mysticete whales are known from the Gulf of Mexico.  

The Bryde’s whale (Balaenoptera edeni) has been sighted most frequently along the 100‐m

(328‐ft) isobath (Davis and Fargion, 1996; Davis et al., 2000).  Most sightings have been made in

the DeSoto Canyon region and off western Florida, although there have been some in the

west‐central portion of the northeastern Gulf.  The minke whale (Balaenoptera acutorostrata) is

considered rare in the Gulf of Mexico, with the only confirmed records coming from strandings

(Würsig et al., 2000).  Based on the available data, it is possible that Bryde’s whales could occur

in the lease area.

Dwarf and pygmy sperm whales.  At sea, it is difficult to differentiate dwarf sperm whales

(Kogia sima) from pygmy sperm whales (Kogia breviceps), and sightings are often grouped

together as “Kogia spp.”  Both species have a worldwide distribution in temperate to tropical

waters.  In the Gulf of Mexico, both species occur primarily along the continental shelf edge and

in deeper waters off the continental shelf (Mullin et al., 1991; Mullin, 2007).  Either species

could occur in the lease area.

Beaked whales.  Four species of beaked whales are known from the Gulf of Mexico.  They are

Blainville’s beaked whale (Mesoplodon densirostris), Cuvier’s beaked whale (Ziphius cavirostris),

Sowerby’s beaked whale (Mesoplodon bidens), and Gervais’ beaked whale (Mesoplodon

europaeus).  Stranding records in the Gulf of Mexico suggest that Gervais’ beaked whale is the

most common and Sowerby’s beaked whale is extralimital.  Due to the difficulties of at‐sea

identification, beaked whales in the Gulf of Mexico are identified either as Cuvier’s beaked

whales or are grouped into an undifferentiated complex (Mesoplodon spp. and Ziphius spp.).  In

the northern Gulf of Mexico, they are broadly distributed in waters greater than 1,000 m

(3,281 ft) over lower slope and abyssal landscapes (Davis et al., 2000).  Any of these species

could occur in the lease area.

Delphinids.  Fourteen species of delphinids are known from the Gulf of Mexico, including

Atlantic spotted dolphin (Stenella frontalis), bottlenose dolphin (Tursiops truncatus), clymene

dolphin (Stenella clymene), false killer whale (Pseudorca crassidens), Fraser’s dolphin

(Lagenodelphis hosei), killer whale (Orcinus orca), melon‐headed whale (Peponocephala electra),

pantropical spotted dolphin (Stenella attenuata), pygmy killer whale (Feresa attenuata),

short‐finned pilot whale (Globicephala macrorhynchus), Risso’s dolphin (Grampus griseus),

rough‐toothed dolphin (Steno bredanensis), spinner dolphin (Stenella longirostris), and striped

dolphin (Stenella coeruleoalba).  The most common non‐endangered cetaceans in the

deepwater environment are the pantropical spotted dolphin, spinner dolphin, and clymene

dolphin.  However, any of these species could occur in the lease area.
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Environmental Impact Analysis for Initial EP Page 39

IPFs potentially affecting non‐endangered marine mammals include drilling rig and drillship

presence, noise, and lights; support vessel and helicopter traffic; and two types of accidents

(a small fuel spill and a large oil spill represented by the WCD for this Initial EP).  Effluent

discharges are likely to have negligible impacts on marine mammals due to rapid dispersion, the

small area of ocean affected, the intermittent nature of the discharges, and the mobility of

marine mammals.  Compliance with NTL 2007‐G03 will minimize the potential for marine

debris‐related impacts on marine mammals.

Impacts of Drilling Rig and Drillship Presence, Noise, and Lights

Noise from routine drilling activities has the potential to disturb marine mammals.  Most

odontocetes (toothed whales and dolphins) use sounds that are higher than the low‐frequency

dominant frequencies produced by OCS drilling activities (Richardson et al., 1995).  Noise

associated with drilling is relatively weak in intensity, and an individual animal’s noise exposure

would be transient.  There are other OCS facilities and activities near the lease area, and the

region as a whole has a large number of similar sources.  Due to the limited scope and short

duration of drilling activities, this project would represent a small temporary contribution to the

overall noise regime, and any short‐term impacts are not expected to be biologically significant

to marine mammal populations.

Drilling rig and drillship lighting and presence are not identified as IPFs for marine mammals in

recent lease sale EISs (MMS, 2007b, 2008).

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb marine mammals, and there is also a risk of

vessel strikes.  Data concerning the frequency of vessel strikes is presented in the lease sale EIS

(MMS, 2007b).  To reduce the potential for vessel strikes, the BOEMRE has issued NTL

2007‐G04, which recommends protected species identification training and that vessel

operators and crews maintain a vigilant watch for marine mammals and slow down or stop their

vessel to avoid striking protected species, and requires operators to report sightings of any

injured or dead protected species.  Vessel operators and crews are required to attempt to

maintain a distance of 91 m (300 ft) or greater when whales are sighted and 45 m (150 ft) when

small cetaceans are sighted.  When cetaceans are sighted while a vessel is underway, vessels

must attempt to remain parallel to the animal’s course and avoid excessive speed or abrupt

changes in direction until the cetacean has left the area.  Vessel operators are required to

reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large assemblages of

cetaceans are observed near an underway vessel, when safety permits.  Compliance with this

NTL will minimize the likelihood of vessel strikes as well as reduce the chance for disturbing

marine mammals, and therefore no significant impacts are expected.

Aircraft traffic also has the potential to disturb marine mammals (Würsig et al., 1998).  However,

while flying offshore, helicopters maintain altitudes above 213 m (700 ft) during transit to and

from the working area.  This altitude will minimize the potential for disturbing marine mammals,

and no significant impacts are expected (MMS, 2007b).

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b, 2008),

and oil impacts on marine mammals in general are discussed by Geraci and St. Aubin (1990).  For
Mississippi Canyon Blocks 762, 805, and 806 April 2011

Environmental Impact Analysis for Initial EP Page 40

this Initial EP, there are no unique site‐specific issues with respect to spill impacts on these

animals.

The probability of a fuel spill will be minimized by Shell’s preventative measures during fuel

transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate

and reduce the potential for impacts on marine mammals.  Initial EP Sections 2j and 9b provide

detail on spill response measures.  Given the open ocean location of the lease area, the duration

of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (MMC, 2010).  However, due to the limited areal extent

and short duration of water quality impacts from a small fuel spill, as well as the mobility of

marine mammals, no significant impacts would be expected.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b, 2008) and

by Geraci and St. Aubin (1990).  For this Initial 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, 2010).  Direct physical and physiological effects can include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey (or

contaminated vegetation, in the case of manatees); and stress from the activities and noise of

response vessels and aircraft.  Complications of the above may lead to dysfunction of immune

and reproductive systems, physiological stress, declining physical condition, and death.  

Behavioral responses can include displacement of animals from prime habitat, disruption of

social structure, changing prey availability and foraging distribution and/or patterns, changing

reproductive behavior/productivity, and changing movement patterns or migration

(MMC, 2010).

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb marine mammals and potentially result in vessel strikes, entanglement, or other

injury or stress.  Response vessels would operate in accordance with NTL 2007‐G04 to reduce

the potential for striking or disturbing these animals, and therefore no significant impacts are

expected.

A blowout resulting in a large oil spill (WCD) 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
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Environmental Impact Analysis for Initial EP Page 41

detailed in Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on marine mammals are expected.

C.3.5 Sea Turtles (Endangered/Threatened)

As listed in Initial EP Section 6h, five species of endangered or threatened sea turtles may be

found near the lease area.  Endangered species are the leatherback (Dermochelys coriacea),

Kemp's ridley (Lepidochelys kempii), and hawksbill (Eretmochelys imbricata) turtles.  The

loggerhead turtle (Caretta caretta) is a threatened species.  The green turtle (Chelonia mydas) is

listed as threatened, except for the Florida breeding population, which is listed as endangered.  

Species descriptions are presented in a recent lease sale EIS (MMS, 2007b).

Leatherbacks and loggerheads are the most likely species to be present near the lease area as

adults.  Green, hawksbill, and Kemp’s ridley turtles are typically inner shelf and nearshore

species, unlikely to occur near the lease area as adults.  Hatchlings or juveniles of any of the sea

turtles may be present in deepwater areas, including the lease area, where they may be

associated with Sargassum and other flotsam.

All five sea turtle species in the Gulf of Mexico are migratory and use different marine habitats

according to their life stage.  These habitats include high‐energy beaches for nesting females

and emerging hatchlings and pelagic convergence zones for hatchling and juvenile turtles.  As

adults, green, hawksbill, and loggerhead turtles forage primarily in shallow, benthic habitats.

Leatherbacks are the most pelagic of the sea turtles, feeding primarily on jellyfish.  

Sea turtle nesting in the northern Gulf of Mexico can be summarized by species as follows:

• Loggerhead turtles – Loggerheads nest in significant numbers along the Florida Panhandle

and, to a lesser extent, from Texas through Alabama (MMS, 2007b).  The nearest significant

nesting area of loggerhead turtles is found in Louisiana, on beaches within the Breton NWR;

• Green and leatherback turtles – Green and leatherback turtles infrequently nest on Florida

Panhandle beaches (Florida Fish and Wildlife Conservation Commission, 2010);

• Kemp’s ridley turtles – The main Kemp’s ridley nesting site is Rancho Nuevo beach,

Tamaulipas, Mexico (NMFS et al., 2010).  Approximately 200 Kemp’s ridley turtles nested on

Texas beaches in 2009 (Sea Turtle Restoration Project, 2011).  Kemp’s ridley turtles typically

do not nest anywhere near the project area, although there have been occasional reports of

Kemp’s ridleys nesting in Alabama (Share the Beach, 2010); and

• Hawksbill turtles – Hawksbills typically do not nest anywhere near the project area.

IPFs potentially affecting sea turtles include drilling rig and drillship presence, noise, and lights;

support vessel and helicopter traffic; and two types of accidents (a small fuel spill and a large oil

spill represented by the WCD for this Initial EP).  Effluent discharges are likely to have negligible

impacts on sea turtles due to rapid dispersion, the small area of ocean affected, and the

intermittent nature of the discharges.  Compliance with NTL 2007‐G03 will minimize the

potential for marine debris‐related impacts on sea turtles.

Impacts of Drilling Rig and Drillship Presence, Noise, and Lights  

Offshore drilling activities produce a broad array of sounds at frequencies and intensities that

may be detected by sea turtles (Geraci and St. Aubin, 1987).  Potential impacts may include
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Environmental Impact Analysis for Initial EP Page 42

behavioral disruption and temporary or permanent displacement from the area near the sound

source.  Certain sea turtles, especially loggerheads, may be attracted to offshore structures

(Lohoefener et al., 1990) and, thus, may be more susceptible to impacts from sounds produced

during routine operations.  Helicopters and service vessels may also affect sea turtles due to

machinery noise and/or visual disturbances.  The most likely impacts would be short‐term

behavioral changes such as diving and evasive swimming, disruption of activities, or departure

from the area.  Due to the limited scope and short duration of drilling activities, these

short‐term impacts are not expected to be biologically significant to sea turtle populations.

Artificial lighting can disrupt the nocturnal orientation of sea turtle hatchlings (Witherington,

1997; Tuxbury and Salmon, 2005).  However, hatchlings may rely less on light cues when they

are offshore than when they are emerging on the beach (Salmon and Wyneken, 1990).  The

NMFS (2007) concluded that the effects of lighting from offshore structures on sea turtles are

insignificant.

Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sea turtles, and there is also a risk of vessel

strikes.  Data show that vessel traffic is one cause of sea turtle mortality in the Gulf of Mexico

(Lutcavage et al., 1997).  While adult sea turtles are visible at the surface during the day and in

clear weather, they can be difficult to spot from a moving vessel when resting below the water

surface, during nighttime, or during periods of inclement weather.  To reduce the potential for

vessel strikes, the BOEMRE has issued NTL 2007‐G04, which recommends protected species

identification training and that vessel operators and crews maintain a vigilant watch for sea

turtles and slow down or stop their vessel to avoid striking protected species, and requires

operators to report sightings of any injured or dead protected species.  When sea turtles are

sighted, vessel operators and crews are required to attempt to maintain a distance of 45 m

(150 ft) or greater whenever possible.  Compliance with this NTL will minimize the likelihood of

vessel strikes as well as reduce the chance for disturbing sea turtles (NMFS, 2007).

Helicopter traffic also has the potential to disturb sea turtles.  However, while flying offshore,

helicopters maintain altitudes above 213 m (700 ft) during transit to and from the working area.  

This altitude will minimize the potential for disturbing sea turtles, and no significant impacts are

expected.

Impacts of a Small Fuel Spill

Potential spill impacts on sea turtles are discussed in recent EISs (MMS, 2007b, 2008) and by the

NMFS (2007) in its Biological Opinion for the Five‐Year Oil and Gas Leasing Program in the

Central and Western Planning Areas of the Gulf of Mexico.  For this Initial EP, there are no

unique site‐specific issues with respect to spill impacts on these animals.

The probability of a fuel spill will be minimized by Shell’s preventative measures during fuel

transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate

and reduce the potential for impacts on sea turtles.  Initial EP Sections 2j and 9b provide detail

on spill response measures.  Given the open ocean location of the lease area, the duration of a

small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and
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Environmental Impact Analysis for Initial EP Page 43

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (MMC, 2010).  However, due to the limited areal extent

and short duration of water quality impacts from a small fuel spill, no significant impacts would

be expected.

A small fuel spill in the lease area would be unlikely to affect sea turtle nesting beaches, as the

lease area is 51 miles (82 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 (WCD)

Impacts of oil spills on sea turtles can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants).  Direct physical and physiological effects can include skin irritation, inflammation,

or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of toxic fumes and

smoke (e.g., from in‐situ burning of oil); ingestion of oil (and dispersants) directly or via

contaminated food; and stress from the activities and noise of response vessels and aircraft.  

Complications of the above may lead to dysfunction of immune and reproductive systems,

physiological stress, declining physical condition, and death.  Behavioral responses can include

displacement of animals from prime habitat, disruption of social structure, changing food

availability and foraging distribution and/or patterns, changing reproductive

behavior/productivity, and changing movement patterns or migration (MMC, 2010).  In the

unlikely event of a spill, implementation of Shell’s OSRP is expected to mitigate and reduce the

potential for these types of impacts on sea turtles.  Initial EP Sections 2j and 9b provide detail

on spill response measures.

Studies of oil effects on loggerheads in a controlled setting (Lutcavage et al., 1995) suggest that

sea turtles show no avoidance behavior when they encounter an oil slick, and any sea turtle in

an affected area would be expected to be exposed.  Sea turtles’ diving behaviors also put them

at risk.  Sea turtles rapidly inhale a large volume of air before diving and continually resurface

over time, which may result in repeated exposure to volatile vapors and oiling (NMFS, 2007).

The OSRA results summarized in Table 3 predict that some shorelines that support sea turtle

nesting could be contacted within 10 to 30 days.  The nearest nesting area of loggerhead turtles

is found in St. Bernard Parish, Louisiana, on beaches within the Breton NWR.  This area has a

contact probability of 1% after 30 days.  The modeling also predicts a 1% probability of

contacting Florida Panhandle shorelines that support significant loggerhead sea turtle nesting.

Spilled oil reaching sea turtle nesting beaches could have effects on nesting sea turtles and egg

development (NMFS, 2007).  An oiled beach could affect nest site selection or result in no

nesting at all (e.g., false crawls).  Upon hatching and successfully reaching the water, hatchlings
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Environmental Impact Analysis for Initial EP Page 44

are subject to the same types of oil spill exposure hazards as adults.  Hatchlings that contact oil

residues while crossing a beach can exhibit a range of effects, from acute toxicity to impaired

movement and normal bodily functions (NMFS, 2007).

Data from the recent Macondo spill provides additional information about potential impacts of a

large oil spill on sea turtles to supplement the analysis presented in the lease sale EIS (MMS,

2007b).  According to NMFS (2010a), approximately 600 dead turtles have been reported since

the Macondo spill.  Species include Kemp’s ridley turtles (481 individuals), loggerhead turtles

(67 individuals), and green turtles (29 individuals).  Oiled turtles include 18 dead individuals and

456 live, oiled animals that were either captured or stranded.  Also, 278 turtle nests were

translocated (271 loggerhead, 4 Kemp’s ridley, and 3 green turtles) and more than

14,000 hatchlings were released.  The strandings and captures ranged from the Louisiana/Texas

border to Cape San Blas in the Florida Panhandle.

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb sea turtles and potentially result in vessel strikes, entanglement, or other injury or

stress.  Response vessels would operate in accordance with NTL 2007‐G04 to reduce the

potential for striking or disturbing these animals, and therefore no significant impacts are

expected.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on sea turtles are expected.

C.3.6 Piping Plover (Threatened)

The Piping Plover (Charadrius melodus) is a migratory shorebird that overwinters along the

southeastern U.S. and Gulf of Mexico coasts.  This threatened species is in decline as a result of

hunting, habitat loss and modification, predation, and disease (USFWS, 2003).  Critical

overwintering habitat has been designated, including beaches in Texas, Louisiana, Mississippi,

Alabama, and Florida (Figure 3).  Piping Plovers inhabit coastal sandy beaches and mudflats,

feeding by probing for invertebrates at or just below the surface.  They use beaches adjacent to

foraging areas for roosting and preening (USFWS, 2010a).  A species description is presented in a

recent lease sale EIS (MMS, 2007b).

A large oil spill (WCD) is the only IPF potentially affecting Piping Plovers.  There are no IPFs

associated with routine project activities that could affect these birds.  A small fuel spill in the

lease area would be unlikely to affect Piping Plovers because a small fuel spill would not be

expected to make landfall or reach coastal waters prior to breaking up (see explanation in

Section A.9.2).
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Environmental Impact Analysis for Initial EP Page 45

Figure 3. Location of selected environmental features in relation to the lease area. Shown are Essential Fish Habitat 

coral reefs; Habitat Areas of Particular Concern (HAPC) for northwestern Gulf of Mexico reefs and banks an

bluefin tuna; critical habitat for beach mice, Gulf sturgeon, Piping Plover, and Whooping Crane; and the Ma
Mississippi Canyon Blocks 762, 805, and 806    April 2011

Environmental Impact Analysis for Initial EP Page 46

Impacts of a Large Oil Spill (WCD)

The lease area is 51 miles (82 km) from the nearest shoreline inhabited by Piping Plovers.  The

OSRA results summarized in Table 3 predict that Texas, Louisiana, and Florida shorelines

designated as critical habitat for the wintering Piping Plover could be contacted by a spill within

30 days.  Plaquemines Parish, which has the highest probability of contact for the 10‐day and

30‐day intervals, includes Piping Plover critical habitat.

Plovers could physically oil themselves while foraging on oiled shores or secondarily

contaminate themselves through ingestion of oiled intertidal sediments and prey (MMS, 2007b).  

Plovers congregate and feed along tidally exposed banks and shorelines, following the tide out

and foraging at the water’s edge.  It is possible that some deaths of Piping Plovers could occur,

especially if spills occur during winter months when plovers are most common along the coastal

Gulf or if spills contacted critical habitat.  Impacts could also occur from vehicular traffic on

beaches and other activities associated with spill cleanup.  Shell has extensive resources

available to protect and rehabilitate wildlife in the event of a spill reaching the shoreline, as

detailed in the OSRP.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on Piping Plovers are expected.

C.3.7 Whooping Crane (Endangered)

The Whooping Crane (Grus americana) is an omnivorous wading bird and an endangered

species.  There are three wild populations in North America (Whooping Crane Eastern

Partnership [WCEP], 2010).  One population winters along the Texas coast at Aransas NWR and

summers at Wood Buffalo National Park in Canada.  This population represents the majority of

the world’s population of free‐ranging Whooping Cranes and reached a record population of

270 at Aransas NWR in December 2008 (WCEP, 2010).  A non‐migrating population has been

re‐introduced in central Florida, and another re‐introduced population summers in Wisconsin

and migrates to the southeastern U.S. for the winter.  Whooping Cranes breed, migrate, winter,

and forage in a variety of habitats, including coastal marshes and estuaries, inland marshes,

lakes, ponds, wet meadows and rivers, and agricultural fields (USFWS, 2007).  About 9,000 ha

(22,240 ac) of salt flats on Aransas NWR and adjacent islands comprise the principal wintering

grounds of the Whooping Crane.  Aransas NWR is designated as critical habitat for the species

(Figure 3).  A species description is presented in a recent lease sale EIS (MMS, 2007b).

A large oil spill (WCD) is the only IPF potentially affecting Whooping Cranes.  A small fuel spill in

the lease area would also be unlikely to affect Whooping Cranes due to the distance from

Aransas NWR.  As explained in Section A.9.2, a small fuel spill would not be expected to make

landfall or reach coastal waters prior to breaking up.

Impacts of a Large Oil Spill (WCD)

A large oil spill is unlikely to affect Whooping Cranes because the lease area is approximately

435 miles (700 km) from its critical habitat (Aransas NWR, Texas) and the OSRA modeling

predicts no contact with shorelines of the Aransas NWR within 30 days.
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Environmental Impact Analysis for Initial EP Page 47

In the event of oil exposure, Whooping Cranes could physically oil themselves while foraging in

oiled areas or secondarily contaminate themselves through ingestion of contaminated shellfish,

frogs, and fishes.  It is possible that some death of Whooping Cranes could occur.  Shell has

extensive resources available to protect and rehabilitate wildlife in the event of a spill reaching

the shoreline, as detailed in the OSRP.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on Whooping Cranes are expected.

C.3.8 Gulf Sturgeon (Threatened)

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is a threatened fish species that inhabits major

rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida

(Barkuloo, 1988; Wakeford, 2001).  An anadromous fish that migrates from the sea upstream

into coastal rivers to spawn in freshwater, it historically ranged from the Mississippi River to

Charlotte Harbor, Florida (Wakeford, 2001).  Today, this range has contracted to encompass

major rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida.  

Populations have been depleted or even extirpated throughout this range by fishing, shoreline

development, dam construction, water quality changes, and other factors (Barkuloo, 1988;

Wakeford, 2001).  These declines prompted the listing of the Gulf sturgeon as a threatened

species in 1991.  The best known populations occur in the Apalachicola and Suwannee Rivers in

Florida (Carr, 1996; Sulak and Clugston, 1998), the Choctawhatchee River in Alabama (Fox et al.,

2000), and the Pearl River in Mississippi/Louisiana (Morrow et al., 1998).  Critical habitat in the

Gulf extends from Lake Borgne, Louisiana (St. Bernard Parish) to Suwannee Sound, Florida

(Levy County) (NMFS, 2010b) (Figure 3).  A species description is presented in a recent lease sale

EIS (MMS, 2007b) and in the recovery plan for this species (USFWS and Gulf States Marine

Fisheries Commission, 1995).

A large oil spill (WCD) is the only IPF potentially affecting Gulf sturgeon.  There are no IPFs

associated with routine project activities that could affect these fishes.  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 (WCD)

Potential spill impacts on Gulf sturgeon are discussed in recent EISs (MMS, 2007b, 2008) and by

the NMFS (2007) in its Biological Opinion for the Five‐Year Oil and Gas Leasing Program in the

Central and Western Planning Areas of the Gulf of Mexico.  For this Initial EP, there are no

unique site‐specific issues with respect to this species.

The lease area is about 117 miles (188 km) from the nearest Gulf sturgeon critical habitat.  The

OSRA modeling (Table 3) predicts that a spill in the lease area has a 1% probability of contacting

the coastal areas inhabited by Gulf sturgeon within 30 days.

In the event of oil reaching Gulf sturgeon habitat, the fish could be affected by direct ingestion,

ingestion of oiled prey, or the absorption of dissolved petroleum products through the gills.  
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Environmental Impact Analysis for Initial EP Page 48

Based on the life history of this species, subadult and adult Gulf sturgeon would be most

vulnerable to an estuarine or marine oil spill, and would be vulnerable only during winter

months (from September 1 through April 30) when this species is foraging in estuarine and

marine habitats (NMFS, 2007).

A blowout resulting in a large oil spill (WCD) 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 Initial 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.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on Gulf sturgeon are expected.

C.3.9 Beach Mice (Endangered)

Four subspecies of endangered beach mouse (Peromyscus polionotus) occur on the barrier

islands of Alabama and the Florida panhandle.  They are the Alabama, Choctawatchee, Perdido

Key, and St. Andrew beach mouse.  Critical habitat has been designated for all four subspecies;

Figure 3 shows the critical habitat combined for all four subspecies.  Species descriptions are

provided in a recent lease sale EIS (MMS, 2007b).  

A large oil spill (WCD) is the only IPF potentially affecting subspecies of beach mouse.  There are

no IPFs associated with routine project activities that could affect these animals due to the

distance from shore and the lack of any onshore support activities near their habitat.  A small

fuel spill in the lease area would not affect any subspecies of beach mouse because a small fuel

spill would not be expected to make landfall or reach coastal waters prior to breaking up (see

explanation in Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on beach mice are discussed in recent EISs (MMS, 2007b, 2008).  For this

Initial EP, there are no unique site‐specific issues with respect to these species.

The lease area is about 158 miles (254 km) from the nearest beach mouse critical habitat.  The

OSRA modeling predicts that a spill in the lease area would not contact beach mouse critical

habitat within 30 days.  (Okaloosa County, Florida, which has a 1% probability after 30 days,

does not include any critical habitat.)

In the event of oil contacting these beaches, beach mice could experience several types of direct

and indirect impacts.  Contact with spilled oil could cause skin and eye irritation and subsequent

infection; matting of fur; irritation of sweat glands, ear tissues, and throat tissues; disruption of

sight and hearing; asphyxiation from inhalation of fumes; and toxicity from ingestion of oil and

contaminated food.  Indirect impacts could include reduction of food supply, destruction of

habitat, and fouling of nests.  Impacts could also occur from vehicular traffic and other activities

associated with spill cleanup.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP
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Environmental Impact Analysis for Initial EP Page 49

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on beach mice are expected.

C.4 Coastal and Marine Birds

C.4.1 Marine and Pelagic Birds

A variety of seabirds may occur in the pelagic environment of the project areas (Clapp et al.,

1982a,b, 1983; Peake, 1996; Hess and Ribic, 2000).  Seabirds spend much of their lives offshore

over the open ocean, except during breeding season when they nest along the coast.  In

addition, other birds such as waterfowl, marsh birds, and shorebirds may occasionally be

present over open ocean areas.  No endangered or threatened bird species are likely to occur at

the project area due to the distance from shore.  For a discussion of shorebirds and coastal

nesting birds, see Section C.4.2.

Seabirds of the northern Gulf of Mexico were surveyed from ships during the GulfCet II program.  

Hess and Ribic (2000) reported that terns, storm‐petrels, shearwaters, and jaegers were the

most frequently sighted seabirds in the deepwater area.  From these surveys, four ecological

categories of seabirds were documented in the deepwater areas of the Gulf: summer migrants

(e.g., shearwaters, storm petrels, and boobies); summer residents that breed in the Gulf

(e.g., Sooty Tern, Least Tern, Sandwich Tern, and Magnificent Frigatebird); winter residents

(e.g., gannets, gulls, and jaegers); and permanent resident species (e.g., Laughing Gull, Royal

Tern, and Bridled Tern) (Hess and Ribic, 2000).

Common seabird species include Wilson’s Storm‐Petrel (Oceanites oceanicus), Magnificent

Frigatebird (Fregata magnificens), Northern Gannet (Morus bassanus), Masked Booby

(Sula dactylatra), Brown Booby (Sula leucogaster), Cory’s Shearwater (Calonectris diomedea),

Greater Shearwater (Puffinus gravis), and Audubon Shearwater (Puffinus lherminieri).  Seabirds

are distributed Gulf‐wide and are not specifically associated with the lease area.

Relationships with hydrographic features were found for several seabird species, possibly due to

effects of hydrography on nutrient levels and productivity of surface waters where birds forage.  

GulfCet II did not estimate bird densities; however, Powers (1987) indicates that seabird

densities over the open ocean typically are <10 birds/km2

.  

Trans‐Gulf migrant birds including shorebirds, wading birds, and terrestrial birds may also be

present in the lease area.  Migrant birds may use offshore structures and platforms for resting,

feeding, or as temporary shelter from inclement weather (Russell, 2005).  Some birds may be

attracted to offshore structures because of the lights and the fish populations that aggregate

around these structures.

IPFs potentially affecting marine and pelagic birds include drilling rig and drillship presence,

noise, and lights; support vessel and helicopter traffic; and two types of accidents (a small fuel

spill and a large oil spill represented by the WCD for this Initial EP).  Effluent discharges are likely

to have negligible impacts on the birds due to rapid dispersion, the small area of ocean affected,

the intermittent nature of the discharges, and the mobility of these animals.  Compliance with

NTL 2007‐G03 will minimize the potential for marine debris‐related impacts on birds.
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Environmental Impact Analysis for Initial EP Page 50

Impacts of Drilling Rig and Drillship Presence, Noise, and Lights

Birds that frequent platforms may be exposed to contaminants including air pollutants and

routine discharges, but significant impacts are unlikely due to rapid dispersion of effluents and

air pollutants.  Birds migrating over water have been known to strike offshore structures,

resulting in death or injury (Wiese et al., 2001; Russell, 2005).  Mortality of migrant birds at tall

towers and other land‐based structures has been reviewed extensively, and the mechanisms

involved in platform collisions appear to be similar.  In some cases, migrants simply do not see a

part of the platform until it is too late.  In other cases, navigation may be disrupted by noise

(Russell, 2005).  On the other hand, offshore structures are suitable stopover habitats for most

trans‐Gulf migrant species, and most of the migrants that stop over on platforms probably

benefit from their stay, particularly in spring (Russell, 2005).  Due to the limited scope and short

duration of drilling activities in this Initial EP, any impacts on populations of either seabirds or

trans‐Gulf migrant birds are not expected to be significant.

A recent study in the North Sea indicated that platform lighting causes circling behavior in

various birds, especially on cloudy nights; apparently the birds’ geomagnetic compass is upset

by the red part of the spectrum from the lights currently in use (Nederlandse Aardolie

Maatschappij, 2007).  The numbers varied greatly, from none at all to some tens of thousands of

birds per night per platform, with an apparent effect radius of up to 3 miles (5 km).  A study in

the Gulf of Mexico also noted the phenomenon, but did not recommend mitigation (Russell,

2005).  Factors to consider in evaluating this impact in the Gulf of Mexico would include the

lower incidence of cloudy and foggy days in the Gulf of Mexico vs. the North Sea.  Due to the

limited scope and short duration of drilling activities proposed in this Initial EP, lighting impacts,

collisions, or other adverse effects are unlikely, and no significant impacts are expected.

Impacts of Support Vessel and Helicopter Traffic

Support vessels and helicopters are unlikely to significantly disturb pelagic birds in open,

offshore waters.  It is likely that individual birds would experience, at most, only short‐term

behavioral disruption, and the impact would not be significant.

Impacts of a Small Fuel Spill

Potential spill impacts on marine birds are discussed in recent EISs (MMS, 2007b, 2008).  For this

Initial 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.  

Initial EP Sections 2j and 9b provide detail on spill response measures.  Given the open ocean

location of the lease area, the duration of a small spill and opportunity for impacts to occur

would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally
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Environmental Impact Analysis for Initial EP Page 51

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Birds exposed to oil on the sea surface could experience direct physical and physiological effects

including skin irritation; chemical burns of skin, eyes, and mucous membranes; and inhalation of

toxic fumes.  Due to the limited areal extent and short duration of water quality impacts from a

small fuel spill, secondary impacts due to ingestion of oil via contaminated prey or reductions in

prey abundance are unlikely.  Due to the low densities of birds in open ocean areas, the small

area affected, and the brief duration of the surface slick, no significant impacts on pelagic birds

would be expected.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine and pelagic birds are discussed in recent EISs (MMS, 2007b,

2008).  For this Initial EP, there are no unique site‐specific issues with respect to spill impacts on

these animals.

Pelagic seabirds could be exposed to oil from a spill at the project area.  Hess and Ribic (2000)

reported that terns, storm‐petrels, shearwaters, and jaegers were the most frequently sighted

seabirds in the deepwater Gulf of Mexico (>200 m).  Powers (1987) indicates that seabird

densities over the open ocean typically are <10 birds/km2

.  The number of pelagic birds that

could be affected in open, offshore waters would depend on the extent and persistence of the

oil slick.

The recent Macondo spill provides relevant information about the species of pelagic birds that

may be affected in the event of a large oil spill.  Birds that have been treated for oiling include

several pelagic species such as the Northern Gannet, Magnificent Frigatebird, and Masked

Booby (International Bird Rescue Research Center, 2010).  The Northern Gannet is among the

species with the largest numbers of birds affected by the spill.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on marine and pelagic birds are

expected.

C.4.2 Shorebirds and Coastal Nesting Birds

Threatened and endangered bird species (Piping Plover and Whooping Crane) have been

discussed previously in Section C.3.  Various species of non‐endangered birds are also found

along the northern Gulf coast, including diving birds, shorebirds, marsh birds, wading birds, and

waterfowl.  Gulf Coast marshes and beaches also provide important feeding grounds and

nesting habitats.  Species that breed on beaches, flats, dunes, bars, barrier islands, and similar

habitats include the Sandwich Tern, Wilson’s Plover, Black Skimmer, Forster’s Tern, Gull‐Billed

Tern, Laughing Gull, Least Tern, and Royal Tern (USFWS, 2010b).  Additional information is

presented in recent lease sale EISs (MMS, 2007b, 2008).

The Eastern Brown Pelican (Pelecanus occidentalis) has been delisted from its endangered status

(USFWS, 2010c), although still listed as endangered by the State of Mississippi (Mississippi
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Environmental Impact Analysis for Initial EP Page 52

Natural Heritage Program, 2003) and as a species of special concern by the State of Florida

(Florida Fish and Wildlife Conservation Commission, 2010).  Brown Pelicans inhabit coastal

habitats and forage within both coastal waters and waters of the inner continental shelf.  Aerial

and shipboard surveys, including GulfCet and GulfCet II, indicate that Brown Pelicans do not

occur in deep offshore waters (Fritts and Reynolds, 1981; Peake, 1996; Hess and Ribic, 2000).  

Nearly half the southeastern population of Brown Pelicans live in the northern Gulf Coast,

generally nesting on protected islands (USFWS, 2010b).

The Southern Bald Eagle (Haliaeetus leucocephalus) was delisted from its threatened status in

the lower 48 states on June 28, 2007.  The Bald Eagle is a terrestrial raptor widely distributed

across the southern U.S., including coastal habitats along the Gulf of Mexico.  The Gulf coast is

inhabited by both wintering migrant and resident Bald Eagles (Johnsgard, 1990; Ehrlich et al.,

1992).

IPFs potentially affecting shorebirds and coastal nesting birds include support vessel and

helicopter traffic and a large oil spill (WCD).  A small fuel spill in the lease area would be unlikely

to affect shorebirds or coastal nesting birds, as the lease area is 51 miles (82 km) from the

nearest shoreline.  As explained in Section A.9.2, a small fuel spill would not be expected to

make landfall or reach coastal waters prior to breaking up.  Compliance with NTL 2007‐G03 will

minimize the potential for marine debris‐related impacts on shorebirds.

Impacts of Support Vessel and Helicopter Traffic

Support vessels and helicopters will transit coastal areas near Port Fourchon and Boothville,

Louisiana, where shorebirds and coastal nesting birds may be found.  These activities could

periodically disturb individuals or groups of birds within sensitive coastal habitats (e.g., wetlands

that may support feeding, resting, or breeding birds).

Vessel traffic may disturb some foraging and resting birds.  Flushing distances vary between

species and between individuals (Rodgers and Schwikert, 2002).  The disturbances will be

limited to flushing birds away from vessel pathways; known distances are from 20 to 49 m (65 to

160 ft) for personal watercraft and 23 to 58 m (75 to 190 ft) for an outboard‐powered boat

(Rodgers and Schwikert, 2002).  Flushing distances may be similar or less for the support vessels

to be used for Shell’s project, and some species such as gulls are attracted to boats.  Support

vessels will not approach nesting or breeding areas on the shoreline, so disturbances to nesting

birds, eggs, and chicks is not expected.  Vessel operators will use designated navigation channels

and comply with posted speed and wake restrictions while transiting sensitive inland

waterways.  Due to the limited scope and short duration of drilling activities, any short‐term

impacts are not expected to be biologically significant to coastal bird populations.

Aircraft traffic can cause some disturbance to birds onshore and offshore.  Responses are highly

dependent on the type of aircraft, the bird species, the activities that animals were previously

engaged in, and previous exposures to overflights (Efroymson et al., 2000).  Helicopters seem to

cause the most intense responses over other human disturbances for some species (Bélanger

and Bédard, 1989).  However, Federal Aviation Administration Advisory Circular No. 91‐36D

recommends that pilots maintain a minimum altitude of 610 m (2,000 ft) when flying over

noise‐sensitive areas such as wildlife refuges, parks, and areas with wilderness characteristics.  

This is greater than the distance (slant range) at which aircraft overflights have been reported to

cause behavioral effects on most species of birds studied (Efroymson et al., 2000).  With these
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guidelines in effect, it is likely that individual birds would experience, at most, only short‐term

behavioral disruption.

Impacts of Large Oil Spill (WCD)

The OSRA results summarized in Table 3 predict that shorelines of Texas, Louisiana, and Florida

that include habitat for shorebirds and coastal nesting birds could be affected within 30 days.

Data from the recent Macondo spill provides additional information about the species of coastal

birds that may be affected in the event that a large oil spill reached coastal habitats; this

information supplements the analysis presented in the lease sale EIS (MMS, 2007b).  According

to USFWS (2010d) and based on the latest reports, about 5,000 dead birds had been collected

since the spill began, and about 1,900 of the dead animals were visibly oiled.  In addition, over

2,000 oiled birds have been collected alive and about 1,200 released (NMFS, 2010a).  According

to the International Bird Rescue Research Center (2010), bird species that were treated for oiling

following the Macondo spill include the following:

• Brown Pelican

• White Pelican

• Masked Booby

• Magnificent Frigatebird

• Laughing Gull

• Herring Gull

• Northern Gannet

• Black Crowned Night Heron

• Tri‐colored Heron

• Green Heron

• Cattle Egret

• Snowy Egret

• Reddish Egret

• Least Bittern

• Common Tern

• Royal Tern

• Caspian Tern

• Sandwich Tern

• Forsters Tern

• Black Tern

• Gull‐billed Tern

• Least Tern

• Black Skimmer

• Black Oystercatcher

• White Ibis

• Roseate Spoonbill

• Willet

• Sanderling

• Dunlin

• Semipalmated Sandpiper

• Killdeer

• King Rail

• Clapper Rail

• Virginia Rail

According to the USFWS (2010d), species with the largest numbers of dead, oiled birds were

Laughing Gull, Northern Gannet, Brown Pelican, Royal Tern, Black Skimmer, Least Tern,

unidentified Gull, and unidentified Tern.  There are no reports of Bald Eagle oiling.

Coastal birds can be exposed to oil as they float on the water’s surface, dive during foraging, or

wade in oiled coastal waters.  Oiled birds can lose the ability to fly, dive for food, or float on the

water, which could lead to drowning (USFWS, 2010e).  Oil interferes with the water repellency

of feathers and can cause hypothermia in the right conditions.  As birds groom themselves, they

can ingest and inhale the oil on their bodies.  Scavengers such as Bald Eagles and gulls can be

exposed to oil by feeding on carcasses of contaminated fish and wildlife.  While ingestion can kill

animals immediately, more often it results in lung, liver, and kidney damage, which can lead to

death.  Bird eggs may be damaged if an oiled adult sits on the nest.
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As noted above, the Brown Pelican was recently removed from the endangered species list.  

Over 300 dead Brown Pelicans have been collected in the Gulf following the Macondo spill,

(USFWS, 2010d).  These data indicate that Brown Pelicans may be particularly at risk of oiling in

the event of a large spill reaching coastal waters.  Issues for Brown Pelicans include direct

contact with oil, disturbance by cleanup activities, and long‐term habitat contamination.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on shorebirds and coastal nesting

birds are expected.

C.5 Fisheries Resources

C.5.1 Pelagic Communities and Ichthyoplankton

Biggs and Ressler (2000) reviewed the biology of pelagic communities in the deepwater

environment of the northern Gulf of Mexico.  The biological oceanography of the region is

dominated by the influence of the Loop Current, whose surface waters are among the most

oligotrophic in the world’s oceans.  Superimposed on this low‐productivity condition are

productive “hot spots” associated with entrainment of nutrient‐rich Mississippi River water and

mesoscale oceanographic features.  Anticyclonic and cyclonic hydrographic features play an

important role in determining biogeographic patterns and controlling primary productivity in the

northern Gulf of Mexico (Biggs and Ressler, 2000).

Most fishes inhabiting shelf or oceanic waters of the Gulf of Mexico have planktonic eggs and

larvae (Ditty, 1986; Ditty et al., 1988; Richards et al., 1989, 1993).  Pelagic eggs and larvae

become part of the planktonic community for various lengths of time (10 to 100 days,

depending on the species) (MMS, 2007b).

IPFs potentially affecting pelagic communities and ichthyoplankton include drilling rig and

drillship presence, noise, and lights; effluent discharges; water intakes; and two types of

accidents (a small fuel spill and a large oil spill [WCD]).

Impacts of Drilling Rig and Drillship Presence, Noise, and Lights

The drilling rig and drillship, as floating structures in the deepwater environment, will act as

fish‐attracting devices (FADs).  In oceanic waters, the FAD effect would be most pronounced for

epipelagic fishes such as tunas, dolphin, billfishes, and jacks, which are commonly attracted to

fixed and drifting surface structures (e.g., 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 and drillship are temporary

structures, impacts on fish populations, whether beneficial or adverse, are considered minor.

Impacts of Effluent Discharges

Treated sanitary and domestic wastes may have a slight effect on the pelagic environment in the

immediate vicinity of these discharges.  These wastes may have elevated levels of nutrients,

organic matter, and chlorine, but should be diluted rapidly to undetectable levels within tens to
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hundreds of meters from the source.  Minimal impacts on water quality, plankton, and nekton

are anticipated.

Deck drainage may have a slight effect on the pelagic environment in the immediate vicinity of

these discharges.  Deck drainage from contaminated areas will be passed through an oil and

water separator prior to release, and discharges will be monitored for visible sheen.  The

discharges may have slightly elevated levels of hydrocarbons but should be diluted rapidly to

undetectable levels within tens to hundreds of meters from the source.  Minimal impacts on

water quality, plankton, and nekton are anticipated.

Other discharges in accordance with the NPDES permit, such as desalination unit brine and

uncontaminated cooling water, fire water, and ballast water, are expected to be diluted rapidly

and have little or no impact on water column biota.

Impacts of Water Intakes

Seawater will be drawn from the ocean for once‐through, non‐contact cooling of machinery

on the drilling rig or drillship.  The estimated intake and discharge of cooling water is

100,000 BPD (4.19 MGD).  Section 316(b) of the Clean Water Act requires NPDES permits to

ensure that the location, design, construction, and capacity of cooling water intake structures

reflect the best technology available to minimize adverse environmental impact from

impingement and entrainment of aquatic organisms.  The current general NPDES Permit

No. GMG 290000 does not specify requirements for existing facilities (those that started

construction before July 16, 2006) and therefore the cooling water intake permit requirements

are not applicable to the Noble Jim Day.  The Noble Bully I does meet the applicability criteria for

a “new” facility as defined by the NPDES permit and therefore is subject to the cooling water

intake permit requirements.  All affected intakes will be in compliance with the design,

monitoring, and recordkeeping requirements of the NPDES permit.

The intake of seawater for cooling water will entrain plankton.  The low intake velocity should

allow most strong‐swimming juvenile fishes and smaller adults to escape entrainment or

impingement.  However, drifting plankton would not be able to escape entrainment with the

exception of a few fast‐swimming larvae of certain taxonomic groups.  Those organisms

entrained may be stressed or killed, primarily through changes in water temperature during the

route from cooling intake structure to discharge structure and mechanical damage (turbulence

in pumps and condensers).  Due to the limited scope and short duration of drilling activities, any

short‐term impacts of entrainment are not expected to be biologically significant to plankton or

ichthyoplankton populations.

Impacts of a Small Fuel Spill

Potential spill impacts on fisheries resources are discussed in recent EISs (MMS, 2007b, 2008).  

For this Initial 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.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Given

the open ocean location of the lease area, the duration of a small spill and opportunity for

impacts to occur would be very brief.
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A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

A small fuel spill could have localized impacts on phytoplankton, zooplankton, and nekton.  Due

to the limited areal extent and short duration of water quality impacts, small fuel spill would be

unlikely to produce detectable impacts on pelagic communities.

Impacts of a Large Oil Spill (WCD)

A large oil spill could affect water column biota including phytoplankton, zooplankton,

ichthyoplankton, and nekton.  A large spill that persisted for weeks or months would be more

likely to affect these communities.  While adult and juvenile fishes may actively avoid a large

spill, planktonic eggs and larvae would be unable to avoid contact.  Eggs and larvae of fishes are

especially vulnerable to oiling because they inhabit the upper layers of the water column, and

they will die if exposed to certain toxic fractions of spilled oil.  Impacts would be potentially

greater if local scale currents retained planktonic larval assemblages (and the floating oil slick)

within the same water mass.

A blowout resulting in a large oil spill (WCD) 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 Initial EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP

will mitigate and reduce the impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Therefore, no significant spill impacts on pelagic communities and

ichthyoplankton are expected.

C.5.2 Essential Fish Habitat

Essential Fish Habitat (EFH) is defined as those waters and substrate necessary to fish for

spawning, breeding, feeding, and growth to maturity.  Under the Magnuson‐Stevens Fishery

Conservation and Management Act, as amended, Federal agencies are required to consult on

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, shrimp, stone crab, spiny lobster, reef fishes, coastal migratory

pelagic fishes, and red drum.  In 2005, the EFH for these managed species was redefined in

Generic Amendment No. 3 to the various Fishery Management Plans (GMFMC, 2005).  The EFH

for most of these GMFMC‐managed species is on the continental shelf in waters shallower than

183 m (600 ft).  The shelf edge is the outer boundary for coastal migratory pelagic fishes, reef

fishes, and shrimp.  EFH for corals and coral reefs includes some shelf‐edge topographic features

on the Texas‐Louisiana OCS, the nearest of which is Sackett Bank, located 32 miles (52 km)

north‐northwest of the lease area.

Highly migratory pelagic fishes, which occur as transients in the lease area, are the only

remaining group for which EFH has been identified in the deepwater Gulf of Mexico.  Species in
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this group, including tunas, swordfishes, billfishes, and sharks, are managed by NMFS.  Highly

migratory species with EFH at or near the lease area include the following (NMFS, 2009):

• Atlantic bigeye tuna (juveniles,

adults)

• Atlantic bluefin tuna (spawn, eggs,

larvae, adults)

• Atlantic skipjack tuna (spawn, eggs,

larvae, adults)

• Atlantic yellowfin tuna (all)

• Atlantic swordfish (all)

• Blue marlin (juveniles, adults)

• White marlin (juveniles, adults)

• Sailfish (juveniles)

• Longbill spearfish (juveniles, adults)

• Oceanic whitetip shark (all)

• Silky shark (all)

• Whale shark (all)

• Longfin mako shark (all)

• Shortfin mako shark (all)

• Bigeye thresher shark (all)

Recent research indicates the central and western Gulf of Mexico may be important spawning habitat

for Atlantic bluefin tuna, and NMFS (2009) has designated a Habitat Area of Particular Concern

(HAPC) for this species.  The HAPC covers much of the deepwater Gulf of Mexico, including the lease

area (Figure 3).  The areal extent of the HAPC is approximately 300,000 km2 (15,000 mi2

).  The

prevailing assumption is that Atlantic bluefin tuna follow an annual cycle of foraging in June through

March off the eastern United States and Canadian coasts, followed by migration to the Gulf of

Mexico to spawn in April, May, and June (NMFS, 2009).  

Other HAPCs have been identified in the Gulf of Mexico by the GMFMC (2005).  These include the

Florida Middle Grounds, Madison‐Swanson Marine Reserve, Tortugas North and South Ecological

Reserves, Pulley Ridge, and several individual reefs and banks of the northwestern Gulf of Mexico

(Figure 3).  The nearest of these is Jakkula Bank, located 138 miles (221 km) west of the lease area.  

Routine IPFs potentially affecting EFH include drilling rig and drillship presence, noise, and lights;

effluent discharges; water intakes; and two types of accidents – a small fuel spill and a large oil spill

(WCD).

Impacts of Drilling Rig and Drillship Presence, Noise, and Lights

The drilling rig and drillship, as floating structures in the deepwater environment, will act as FADs.  In

oceanic waters, the FAD effect would be most pronounced for epipelagic fishes such as tunas,

dolphin, billfishes, and jacks, which are commonly attracted to fixed and drifting surface structures

(Holland et al., 1990; Higashi, 1994; Relini et al., 1994).  This FAD effect would possibly enhance

feeding of epipelagic predators by attracting and concentrating smaller fish species.  Because the

drilling rig and drillship are temporary structures, any impacts on EFH for highly migratory pelagic

fishes are considered minor.

Impacts of Effluent Discharges

Other effluent discharges affecting EFH by diminishing ambient water quality include drilling muds

and cuttings, treated sanitary and domestic wastes, deck drainage, and miscellaneous discharges

such as desalination unit brine and uncontaminated cooling water, fire water, and ballast water.  

Impacts on water quality have been discussed previously.  No significant impacts on EFH for highly

migratory pelagic fishes are expected from these discharges.
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Impacts of Water Intakes

As noted previously, cooling water intake will cause entrainment and impingement of plankton,

including fish eggs and larvae (ichthyoplankton).  Due to the limited scope and short duration of

drilling activities, any short‐term impacts on EFH for highly migratory pelagic fishes are not expected

to be biologically significant.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the potential for impacts on EFH.  Initial EP Sections 2j and 9b provide detail on

spill response measures.  Given the open ocean location of the lease area, the duration of a small spill

and opportunity for impacts to occur would be very brief.

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008).  For this Initial EP,

there are no unique site‐specific issues with respect to spill impacts.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at the

time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate of a

small fuel spill and indicates that over 90% would be evaporated or dispersed naturally within

24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha (1.2 to

12 ac), depending on sea state and weather conditions.

A small fuel spill could have localized impacts on EFH for highly migratory pelagic fishes, including

tunas, swordfishes, billfishes, and sharks.  These species occur as transients in the lease area.  A spill

would also produce short‐term impact on water quality in the HAPC for spawning Atlantic bluefin

tuna, which covers much of the deepwater Gulf of Mexico.  The areal extent of the affected area

would represent a negligible portion of the HAPC.

A small fuel spill would not affect EFH for corals and coral reefs, the nearest of these EFH areas being

Sackett Bank, located 32 miles (52 km) north‐northwest of the lease area.  A small fuel spill would

float and dissipate on the sea surface and would not contact these features.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008).  For this Initial EP,

there are no unique site‐specific issues with respect to EFH.

An oil spill in offshore waters would temporarily increase hydrocarbon concentrations on the water

surface and potentially the subsurface as well.  Given the extent of EFH designations in the Gulf of

Mexico (GMFMC, 2005; NMFS, 2009), some impact on EFH would be unavoidable.

A large spill could affect the EFH for many managed species including shrimp, stone crab, spiny

lobster, reef fishes, coastal migratory pelagic fishes, and red drum.  It would result in adverse impacts

on water quality and water column biota including phytoplankton, zooplankton, and nekton.  In

coastal waters, sediments could be contaminated and result in persistent degradation of the seafloor

habitat for managed demersal fish and shellfish species.

The lease area is within the HAPC for spawning Atlantic bluefin tuna (NMFS, 2009).  A large spill could

temporarily degrade the HAPC due to increased hydrocarbon concentrations in the water column,

with the potential for lethal or sublethal impacts on spawning tuna.  Potential impacts would depend

in part on the timing of a spill, as this species migrates to the Gulf of Mexico to spawn in April, May,

and June (NMFS, 2009).
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The pinnacle trend area, located 100 miles (160 km) north from the lease area, is designated as EFH

under the corals and coral reefs management plan.  An accidental spill would be unlikely to affect this

area.  A surface slick would not reach these features.  Although there are reports of subsurface

plumes resulting from the use of subsea dispersants during the Macondo spill, the distance and

difference in water depth are factors that would make an impact unlikely.  Near‐bottom currents in

the region are expected to flow along the isobaths (Nowlin et al., 2001) and typically would not carry

a plume up onto the continental shelf edge.

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on EFH are expected.

C.6 Archaeological Resources

C.6.1 Shipwreck Sites

MC 762 is on the list of leases with a high potential for historic shipwrecks.  An Archaeological

Assessment was conducted by C&C Technologies, Inc. (2008).  There were 1,152 unidentified sonar

contacts located within the lease area.  These sonar contacts were characteristic of modern debris

primarily associated with industrial dumping or lease development activities.  No shipwrecks were

found within MC 762.  

Because there are no historic shipwreck sites in the lease area, there are no routine IPFs that are

likely to affect these resources.  Impacts of a large oil spill (WCD) are the only IPFs considered.  

A small fuel spill would not affect shipwrecks because the oil would float and dissipate on the sea

surface.

Impacts of a Large Oil Spill (WCD)

The MMS (2007b) estimated that a severe subsurface blowout could resuspend and disperse

sediments within a 300‐m (984‐ft) radius.  Because there are no historic shipwrecks in the lease area,

this impact would not be relevant.

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

archaeological sites beyond the immediate vicinity of the wellhead (i.e., due to physical impacts of a

blowout) because the oil would rise quickly to the sea surface directly over the spill location.  

However, during the Macondo spill, subsurface plumes were reported at a water depth of about

1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsite and persisting for more than

a month (Camilli et al., 2010).  The subsurface plumes apparently resulted from the use of

dispersants at the wellhead (Joint Analysis Group, 2010c).  While the behavior and impacts of

subsurface plumes are not well known, a subsurface plume could have the potential to contact

shipwreck sites beyond the 300‐m (984‐ft) radius estimated by MMS (2007a, 2008), depending on its

extent, trajectory, and persistence.  If oil from a subsea spill should come into contact with wooden

shipwrecks on the seafloor it could adversely affect their condition or preservation.  Should there be

any indication that potential shipwreck sites could be affected, in accordance with NTL 2005‐G07

Shell will immediately halt operations, take steps to ensure that the site is not disturbed in any way,

and contact the Regional Supervisor, Leasing and Environment, within 48 hours of its discovery.  Shell

would cease all operations within 305 m (1,000 ft) of the site until the Regional Director provides

instructions on steps to take to assess the site’s potential historic significance and protect it.

A spill entering shallow coastal waters could conceivably contaminate an undiscovered shipwreck

site.  The OSRA modeling summarized in Table 3 predicts that Texas, Louisiana, and Florida shorelines

could be contacted by a spill within 30 days.  Also as noted by MMS (2007b), should an oil spill
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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.

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on historic shipwrecks are expected.

C.6.2 Prehistoric Archaeological Sites

With water depths ranging from 1,149 to 1,155 m (3,769 to 3,789 ft), the wellsites are well beyond

the 60‐m (197‐ft) depth contour used by the BOEMRE as the seaward extent for prehistoric

archaeological site potential in the Gulf of Mexico.  Because prehistoric archaeological sites are not

found in the lease area, the only relevant IPF is a large oil spill (WCD).  A small fuel spill would not

affect prehistoric archaeological resources because the oil would float and dissipate on the sea

surface.

Impacts of a Large Oil Spill (WCD)

Because prehistoric archaeological sites are not found in the lease area, they would not be affected

by the physical effects of a subsea blowout.  The MMS (2007b) estimates that a severe subsurface

blowout could resuspend and disperse sediments within a 300‐m (984‐ft) radius.

Along the northern Gulf coast, prehistoric sites occur frequently along the barrier islands and

mainland coast and along the margins of bays and bayous (MMS, 2007b).  The OSRA modeling

summarized in Table 3 predicts that Texas, Louisiana, and Florida shorelines could be contacted by a

spill within 30 days.  A spill reaching a prehistoric site along these shorelines could coat fragile

artifacts or site features and compromise the potential for radiocarbon dating organic materials in a

site (although other dating methods are available and it is possible to decontaminate an oiled sample

for radiocarbon dating).  Coastal prehistoric sites could also be damaged by spill cleanup operations

(e.g., by destroying fragile artifacts and disturbing the provenance of artifacts and site features).

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on archaeological resources are expected.

C.7 Coastal Habitats and Protected Areas

Coastal habitats in the northeastern Gulf of Mexico that may be affected by oil and gas activities are

described in recent EISs (MMS, 2007b, 2008) and in a literature review by Collard and Way (1997).  

Sensitive coastal habitats are also tabulated in the OSRP.  Coastal habitats inshore of the project area

include barrier beaches and dunes, wetlands, and submerged seagrass beds.  Generally, most of the

northeastern Gulf is fringed by barrier beaches, with wetlands and/or submerged seagrass beds

occurring in sheltered areas behind the barrier islands and in estuaries.

Due to the distance from shore, there are no IPFs associated with routine activities that are likely to

affect beaches and dunes, wetlands, seagrass beds, coastal wildlife refuges, wilderness areas, or any

other managed or protected coastal area.  The support bases at Port Fourchon and Boothville are not

located in a wildlife refuge or a wilderness area.  Potential impacts of support vessel traffic are briefly

addressed below.
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A small fuel spill in the lease area would be unlikely to affect coastal habitats, as the lease area is 51

miles (82 km) from the nearest shoreline.  As explained in Section A.9.2, a small fuel spill would not

be expected to make landfall or reach coastal waters prior to breaking up.

Impacts of Support Vessel Traffic

For OCS activities in general, support operations, including crew boats and supply boats, may have a

minor incremental impact on coastal habitats.  Over time with a large number of vessel trips, vessel

wakes can erode shorelines along inlets, channels, and harbors.  Support operations, including crew

boats and supply boats as detailed in Initial 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 (WCD)

Potential spill impacts on coastal habitats are discussed in recent EISs (MMS, 2007b, 2008).  Coastal

habitats inshore of the project area include barrier beaches and dunes, wetlands, and submerged

seagrass beds.  For this Initial EP, there are no unique site‐specific issues with respect to coastal

habitats.

The OSRA results summarized in Table 3 predict that shorelines of Texas, Louisiana, and Florida could

be affected within 30 days.  Plaquemines Parish, Louisiana, has the highest probability of contact for

the 10‐day and 30‐day intervals (4% and 8%, respectively).  Two other Louisiana parishes (Terrebonne

and Lafourche) may be contacted within 10 days.  After 30 days, 11 counties or parishes may be

contacted from Galveston, Texas, to the Okaloosa County in the Florida Panhandle.

The shorelines within the geographic range predicted by the OSRA modeling include extensive barrier

beaches and wetlands, with submerged seagrass beds occurring in sheltered areas behind the barrier

islands and in estuaries.  National wildlife refuges and other protected areas
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along the coast are discussed in the lease sale EIS (MMS, 2007b) and Shell’s OSRP.  Coastal

wildlife refuges, wilderness areas, and state and national parks within the geographic range of

the potential shoreline contacts after 30 days include the following:

• Galveston Island State Park

• Brazoria NWR

• Apffel Park

• Seawolf Park

• Old Fort Travis Park

• Atkinson Island Wildlife Management

Area (WMA)

• Ft. Anahuac Park

• Anahuac NWR

• McFaddin NWR

• Sea Rim State Park

• J.D. Murphree WMA

• Texas Point NWR

• Sabine NWR

• Cameron Prairie NWR

• LaCassine NWR

• Little Pecan Island Preserve

• Peveto Woods  Sanctuary

• Lower Neches WMA

• Rockefeller State Wildlife Refuge and

Game Preserve

• Paul J. Rainey WMA

• Marsh Island WMA

• Cypremort Point State Park

• Atchafalaya Delta WMA

• Mandalay NWR

• Isles Dernieres Barrier Islands Refuge

• Pointe Au Chien WMA

• Wisner WMA

• Grand Isle State Park

• Salvador WMA

• Jean Lafitte National Historical Park

and Preserve

• Delta NWR

• Pass a Loutre WMA

• Breton NWR

• St. Bernard State Park

• Biloxi WMA

• Bayou Sauvage NWR

• Gulf Islands National Seashore
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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.

Wetlands are highly sensitive to oiling.  The MMS (2007b) predicted that for every 50 bbl of oil

contacting wetlands, approximately 2.7 ha (6.7 ac) of wetland vegetation will experience dieback.  

Thirty percent of these damaged wetlands are assumed to recover within 4 years, and 85% within 10

years.  About 15% of the contacted wetlands are expected to be converted permanently to open‐

water habitat.  The critical concentration of oil is that concentration above which impacts to wetlands

will be long‐term and recovery will take longer than two growing seasons, and which causes plant

mortality and some permanent wetland loss.  Critical concentrations of various oils are expected to

vary broadly for wetland types and wetland plant species.  Louisiana wetlands are assumed to be

more sensitive to oil contact than elsewhere in the Gulf because of high cumulative stress (MMS,

2007b).  In addition to the direct impacts of oil, cleanup activities in marshes may accelerate rates of

erosion and retard recovery rates, which have been reported to require from years to decades

following a spill (MMS, 2007b).

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on coastal habitats are expected.

C.8 Socioeconomic and Other Resources

C.8.1 Recreational and Commercial Fishing

The main commercial fishing activity in deep waters of the northern Gulf of Mexico is pelagic

longlining for tunas, swordfishes, and other billfishes (Continental Shelf Associates, Inc., 2002).  

Pelagic longlining has occurred historically in the project area, primarily during spring and summer.  

In August 2000, the Federal government closed two areas in the northeastern Gulf of Mexico to

longline fishing (65 Federal Register 47214, August 1, 2000).  The lease is outside of the closure areas.

Longline gear consists of monofilament line deployed from a moving vessel and generally allowed to

drift for 4 to 5 hours (Continental Shelf Associates, Inc., 2002).  As the mainline is put out, baited

leaders and buoys are clipped in place at regular intervals.  It takes 8 to 10 hours to deploy a longline

and about the same time to retrieve it.  Longlines are often set near oceanographic features such as

fronts or downwellings, with the aid of sophisticated on‐board temperature sensors, depth finders,

and positioning equipment.  Vessels are 10 to 30 m long, and their trips last from about 1 to 3 weeks.  
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Environmental Impact Analysis for Initial EP Page 64

The main homeports for longlining vessels are in Louisiana (Dulac and Venice) and Florida (Destin,

Madeira Beach, and Panama City).

It is unlikely that any commercial fishing activity other than longlining occurs at or near the project

area.  Benthic species targeted by commercial fishers occur on the upper continental slope, well

inshore of the project area.  Royal red shrimp are caught by trawlers in water depths of about 250 to

550 m (820 to 1,804 ft).  Tilefish are caught by bottom longlining in water depths from about 165 to

450 m (540 to 1,476 ft) (Continental Shelf Associates, Inc., 2002).

Most recreational fishing activity in the region occurs in water depths less than 200 m (656 ft)

(Continental Shelf Associates, Inc., 1997, 2002).  In deeper water, the main attraction to recreational

fishers would be petroleum platforms offshore Texas and Louisiana.  The nearby Mars and Ursa TLPs

are known sites of recreational fishing in the region (Continental Shelf Associates, Inc. (2002).

The only routine IPF potentially affecting fisheries is drilling rig and drillship presence (including noise

and lights).  Two potential accidents are also addressed below – a small fuel spill and a large oil spill

(WCD).

Impacts of Drilling Rig and Drillship Presence

There is a slight possibility of pelagic longlines becoming entangled in the drilling rig or drillship.  For

example, in January 1999, a portion of a pelagic longline snagged on the acoustic Doppler current

profiler of a drillship working in the Gulf of Mexico (Continental Shelf Associates, Inc., 2002).  The line

was removed without incident.  Generally, longline fishers use radar and are aware of offshore

structures and ships when placing their sets.  Therefore, little or no impact on pelagic longlining is

expected.

No adverse impacts on fishing activities are anticipated.  Other factors such as effluent discharges are

likely to have negligible impacts on commercial or recreational fisheries due to rapid dispersion, the

small area of ocean affected, and the intermittent nature of the discharges.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the potential for impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Given the open ocean location of the lease area, the duration of a small spill and

opportunity for impacts to occur would be very brief.

Pelagic longlining activities in the lease area, if any, could be interrupted in the event of a small fuel

spill.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha (1.2 to 12 ac),

depending on sea state and weather conditions.  Fishing activities could be interrupted due to the

activities of response vessels operating in the lease area.  A small fuel spill would not affect coastal

water quality because the spill would not be expected to make landfall or reach coastal waters prior

to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on fishing activities are discussed in recent EISs (MMS, 2007b, 2008).  For this

Initial EP, there are no unique site‐specific issues with respect to this activity.

Pelagic longlining activities in the lease area and other fishing activities in the northern Gulf of Mexico

could be interrupted in the event of a large oil spill.  A spill may or may not result in fishery closures,

depending on the duration of the spill, the oceanographic and meteorological conditions at the time,

and the effectiveness of spill response measures.  The recent Macondo spill provides information

about the maximum potential extent of fishery closures in the event of a large oil spill in the Gulf of

Mexico (NMFS, 2010c).  At its peak on July 12, 2010, closures encompassed 217,821 km2 (84,101 mi2

),

or 34.8% of the U.S. Exclusive Economic Zone (EEZ) in the Gulf of Mexico.
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Environmental Impact Analysis for Initial EP Page 65

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on fishing activities are expected.

C.8.2 Public Health and Safety

There are no IPFs associated with routine operations that are expected to affect public health and

safety.  Impacts of a small fuel spill and a large oil spill (WCD) are addressed below.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the potential for impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.   

A small fuel spill would not have any impacts on public health and safety because it would affect only

a small area of the open ocean 51 miles (82 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 (WCD)

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 and drillship maintain a Shipboard Oil

Pollution Emergency Plan as required under MARPOL 73/78.

Depending on the spill rate and duration, the physical/chemical characteristics of the oil, the

meteorological and oceanographic conditions at the time, and the effectiveness of spill response

measures, the public could be exposed to oil on the water and along the shoreline, including skin

contact or breathing VOCs.  Crude oil is a highly flammable material, and any smoke or vapors from a

crude oil fire can cause irritation, and in large quantities may pose a health hazard.

Data from the recent Macondo spill provide relevant information about the types of health issues

that may occur in the event of a large oil spill (Centers for Disease Control and Prevention, 2010a).  

Wildlife cleaning  and rehabilitation workers have reported concerns including scrapes and cuts, itchy

or red skin or rash, and symptoms of headache or feeling faint, dizzy, or fatigued.  Hand, shoulder, or

back pain was also reported by some wildlife cleaning workers.  Personnel working on offshore

vessels or providing direct oversight to offshore vessels, including USCG personnel, civilian

contractors, and other responders who were exposed to oil and dispersants, had 7 to 12 times higher

prevalences of upper respiratory symptoms and cough than those not exposed (Centers for Disease

Control and Prevention, 2010b).  Another potential occupational hazard for spill response workers in

general was heat stress from work in a hot and humid environment.  Initial symptoms from cleanup

workers who sought medical care in Louisiana were typical of acute exposure to hydrocarbons or H2S

such as headaches, dizziness, nausea, vomiting, cough, respiratory distress, and chest pain (Solomon

and Janssen, 2010).  Health effects reported from previous oil spills, such as the Exxon Valdez in 1989,

were primarily acute injuries consisting of headaches, throat irritation, and sore or itchy eyes, but

respiratory problems and dermatitis along with chronic airway disease have also been reported

(Solomon and Janssen, 2010).

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce
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Environmental Impact Analysis for Initial EP Page 66

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on public health and safety are expected.

C.8.3 Employment and Infrastructure

There are no IPFs associated with routine operations that are expected to affect employment and

infrastructure.  The project involves drilling with support from existing shorebase facilities in

Louisiana.  No new or expanded facilities will be constructed, and no new employees are expected to

move permanently into the area.  The project will have a negligible impact on socioeconomic

conditions such as local employment, existing offshore and coastal infrastructure (including major

sources of supplies, services, energy, and water), and minority and lower income groups.  Impacts of

a small fuel spill and a large oil spill (WCD) are addressed below.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the potential for impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Given the open ocean location of the lease area, the duration of a small spill and

opportunity for impacts to occur would be very brief.

A small fuel spill that is dissipated within a few days would have little or no economic impact, as the

spill response would use existing facilities, resources, and personnel.

Impacts of a Large Oil Spill (WCD)

Potential socioeconomic impacts of an oil spill are discussed in recent EISs (MMS, 2007b, 2008).  For

this Initial EP, there are no unique site‐specific issues with respect to employment and coastal

infrastructure.  A large spill could cause economic impacts in several ways: it could result in extensive

fishery closures that put fishermen out of work; it could result in temporary employment as part of

the response effort; it could result in adverse publicity that affects employment in coastal recreation

and tourism industries; and it could result in another suspension of OCS drilling activities, including

service and support operations that are an important part of local economies.

The lease area is 51 miles (82 km) from the nearest shoreline.  Based on OSRA modeling as

summarized in Table 3, Texas, Louisiana, and Florida coastal areas are the most likely to be contacted

by a spill.  It is not known whether other, more distant coastal areas could be affected if an oil spill

persisted for more than 30 days.

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on employment and infrastructure are expected.

C.8.4 Recreation and Tourism

There are no known recreational uses of the lease area.  Recreational resources and tourism in

coastal areas would not be affected by any routine activities due to the distance from shore.  

Compliance with NTL 2007‐G03 will minimize the chance of trash or debris being lost overboard from

the drilling rig or drillship and subsequently washing up on beaches.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Shell’s preventative measures during routine

operations including fuel transfer.  In the unlikely event of a spill, implementation of Shell’s OSRP will

mitigate and reduce the potential for impacts.  Initial EP Sections 2j and 9b provide detail on spill

response measures.  Given the open ocean location of the lease area, the duration of a small spill and

opportunity for impacts to occur would be very brief.
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Environmental Impact Analysis for Initial EP Page 67

A small fuel spill in the lease area would be unlikely to affect recreation and tourism.  There are no

known recreational or tourism activities occurring in the lease area, and as explained in

Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters prior

to breaking up.

Impacts of a Large Oil Spill (WCD)

Potential impacts of an oil spill on recreation and tourism are discussed in recent EISs (MMS, 2007b,

2008).  For this Initial 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.  Based on OSRA modeling as

summarized in Table 3, Plaquemines Parish, Louisiana, is the area most likely to be contacted by a

spill.  However, shorelines from Galveston, Texas, to the Florida Panhandle could be contacted.  

These areas include popular beaches and recreational sites along the coast.  It is not known whether

other, more distant coastal areas could be affected if an oil spill persisted for more than 30 days.

In addition to the analysis presented by MMS (2007b, 2008), recent and ongoing studies have

explored the economic impacts of the Macondo spill including tourism and “brand” damage (IEM,

2010; Oxford Economics, 2010).  The U.S. Travel Association has estimated the economic impact of

the Macondo spill on tourism across the Gulf Coast over a 3‐year period at $22.7 billion (Oxford

Economics, 2010).  There are ongoing efforts to accelerate recovery by informing public perceptions;

creating travel incentives; and providing access to capital, low interest loans, and tax incentives for

affected businesses (U.S. Travel Association, 2010).

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on recreation and tourism are expected.

C.8.5 Land Use

Land use along the northern Gulf coast is discussed in recent lease sale EISs (MMS, 2007b, 2008).  

There are no routine IPFs potentially affecting land use.  The project will use existing onshore support

facilities in Louisiana.  The land use at the existing shorebase sites is industrial.  The project will not

involve any new construction or changes to existing land use and, therefore, will not have any

impacts.  Levels of boat and helicopter traffic, as well as demand for goods and services including

scarce coastal resources, will represent a small fraction of the level of activity occurring at the

shorebases.

A large oil spill (WCD) is the only relevant IPF.  A small fuel spill would not have any impacts on land

use, as the response would be staged out of existing shorebases and facilities.

Impacts of a Large Oil Spill (WCD)

The initial response for a large oil spill would be staged out of existing facilities, with no effect on land

use.  A large spill could have limited temporary impacts on land use along the coast if additional

staging areas were needed.  For example, during the Macondo spill, temporary staging areas were

established in Louisiana, Mississippi, Alabama, and Florida for spill response and cleanup efforts.  In

the event of a large spill in the lease area, similar temporary staging areas could be needed.  These

areas would eventually return to their original use as the response is demobilized.

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce
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Environmental Impact Analysis for Initial EP Page 68

the impacts.  Initial EP Sections 2j and 9b provide detail on spill response measures.  Therefore, no

significant spill impacts on land use are expected.

C.8.6 Other Marine Uses

The lease area is not located within any USCG‐designated fairway or shipping lane.  MC 762 is not in a

designated Military Warning Area.  Shell will comply with BOEMRE requirements and lease

stipulations to avoid impacts on uses of the area by military vessels and aircraft.

There are existing subsea facilities on the seafloor in the lease area.  All pre‐existing seafloor

hardware, flowlines, and umbilicals have a 152‐m (500‐ft) avoidance buffer around each item to

prevent impacts.  

A discontinued industrial waste dump area that was active in the 1970s is located to the southwest of

the lease area (C&C Technologies, Inc., 2008).  Shell has prepared a BOEMRE‐approved plan for

“Waste Barrel Avoidance and Release Response in the Mississippi Canyon Area” that applies to

operations that could cause a disturbance of a seafloor barrel.  Shell’s over‐arching policy is to avoid

barrel contact.  The plan specifies a safe stand‐off distance from the waste barrels of 10 m (33 ft) and

requires that potential impact locations be surveyed with an ROV to maximize barrel avoidance.  In

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

specifies actions to be taken for the topside safety of personnel handling the equipment.  The plan

also outlines barrel impact reporting procedures.

There are no IPFs from routine project activities that are likely to affect shipping or other marine

uses.  Physical disturbance to existing wells, flowlines, and umbilicals will be prevented by the 152‐m

(500‐ft) avoidance zone established around these features.  A large oil spill (WCD) is the only relevant

accident IPF.  A small fuel spill would not have any impacts on other marine uses, as the spill and

response activities would be mainly within the lease area and the duration would be brief.

Impacts of a Large Oil Spill (WCD)

An accidental spill would be unlikely to significantly affect shipping or other marine uses.  The block is

not located within any USCG‐designated fairway or shipping lane.  In the event of a large spill

requiring numerous response vessels, coordination would be required to manage the vessel traffic

for safe operations.  Shell will comply with BOEMRE requirements and lease stipulations to avoid

impacts on uses of the area by military vessels and aircraft.

In the event of a large spill requiring numerous vessels in the area, coordination would be required to

ensure that no anchoring or seafloor‐disturbing activities occur near the existing pipelines and

flowlines.  In addition, the procedures detailed in Shell’s Waste Barrel Avoidance and Release

Response Plan would be adhered to during response to any spill in the area.

A blowout resulting in a large oil spill (WCD) 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 Initial

EP Section 2j.  In the unlikely event of a spill, implementation of Shell’s OSRP will mitigate and reduce

the impacts.  Initial EP Sections 2j and 9b provide 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.
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Environmental Impact Analysis for Initial EP Page 69

Prior Studies.  MC 762 was acquired in Lease Sale #98 on 22 May 1985.  Prior to the lease sale, MMS

prepared a multisale EIS in which it analyzed the environmental impact of activities that might occur

in the multi‐lease‐sale area.  The MMS also recently analyzed the cumulative impacts of

OCS development activities similar to those planned in this Initial EP in several documents.  The level

and types of activities planned in Shell's Initial EP are within the range of activities described and

evaluated in the Final EIS for Gulf of Mexico OCS Oil and Gas Lease Sales 2007‐2012: Western

Planning Area Sales 204, 207, 210, 215, and 218, and Central Planning Area Sales 205, 206, 208, 213,

216, and 222 (MMS, 2007b), as updated by a 2008 Final Supplemental EIS for Gulf of Mexico OCS Oil

and Gas Lease Sales 2009‐2012: Central Planning Area Sales 208, 213, 216, and 222 and Western

Planning Area Sales 210, 215, and 218 (MMS, 2008).  Past, present, and reasonably foreseeable

activities were identified in the cumulative effects scenario.  These documents are incorporated by

reference.

Description of Activities Reasonably Expected to Occur in the Vicinity of Project Area.  During the

time frame of the drilling and completion activities included in this Initial EP, Shell will be conducting

ongoing development and production activities in MC 807 associated with the Mars field

development.  Shell currently is unaware of any other projects that are planned to occur in lease

blocks adjacent to those included in this Initial EP.

Cumulative Impacts of Activities in the Initial EP.  The MMS (2007b) multi‐lease‐sale EIS included a

lengthy discussion of cumulative impacts, which analyzed the environmental and socioeconomic

impacts from the incremental impact of the 11 proposed lease sales, in addition to all activities

(including non‐OCS activities) projected to occur from past, proposed, and future lease sales during

the 40‐year period of 2007 to 2046 (see EIS page 4‐301).  The EIS considered exploration, delineation,

and development wells; platform installation; service‐vessel trips; and oil spills.  The EIS examined the

potential cumulative effects on each specific resource for the entire Gulf of Mexico.

The level and type of activity proposed in Shell’s Initial 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 Initial EP, in conjunction with the other reasonably foreseeable activities

expected to occur in the Gulf of Mexico, as well as the known impacts from the Macondo spill in

MC 252.  While another large oil spill could have significant impacts, the numerous new safety

measures implemented by the BOEMRE and further mitigation and safety measures proposed by

Shell in its Initial EP result in a drilling program that reduces the likelihood of another large spill and

improves the effectiveness of any response in the extremely unlikely event that another large spill

occurs.  Thus, for all 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 Initial EP is limited in geographic scope and duration, and the impacts on the

physical/chemical environment will be correspondingly limited.  

Air Quality.  Emissions from pollutants into the atmosphere from activities are not projected to have

significant effects on onshore air quality because of the prevailing atmospheric conditions, emission

rates and heights, and resulting pollutant concentrations.  As the BOEMRE found in the multi‐lease‐

sale EISs, the incremental contribution of activities similar to Shell’s proposed activities to the

cumulative impacts is not significant and will not cause or contribute to a violation of any national

ambient air quality standard (MMS, 2007b, 2008).  In addition, the cumulative contribution to

visibility impairment is also very small (MMS, 2007b, 2008).  Since the BOEMRE completed the multi‐

lease‐sale EISs, USEPA has adopted a new short‐term NAAQS for nitrogen dioxide.  The standard has

not yet been implemented in the Gulf Coast states, but given the levels of expected emissions and

the distance of the project from shore, emissions from Shell's Initial EP are not likely to contribute to

violations of any NAAQS onshore.
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Environmental Impact Analysis for Initial EP Page 70

Climate Change.  Carbon dioxide (CO2) and CH4 emissions from the project would constitute a small

incremental contribution to greenhouse gas emissions from all OCS activities.  According to the

Programmatic EIS (MMS, 2007a), estimated CO2 emissions from all OCS activities in the 2007‐2012

leasing program are about 0.08% to 0.016% of the global CO2 emissions from fossil fuel combustion.  

Greenhouse gas emissions may contribute to climate change, with important effects on temperature,

rainfall, frequency of severe weather, ocean acidification, and sea level rise (Intergovernmental Panel

on Climate Change, 2007).  In the Gulf of Mexico, sea level rise is an important issue due to the

ongoing losses in coastal wetlands, particularly in coastal Louisiana.  Greenhouse gas emissions from

the Initial EP represent a negligible contribution to the total greenhouse gas emissions from

reasonably foreseeable activities in the Gulf of Mexico area and would not significantly alter any of

the climate change impacts evaluated in the lease sale EIS or Programmatic EIS.  Globally, Shell is

working to reduce greenhouse gas emissions by increasing the efficiency of its operations,

establishing a substantial capability in CO2 capture and storage, and continuing to research and

develop technologies that increase efficiency and reduce emissions in hydrocarbon production.  

Shell’s direct greenhouse gas emissions in 2009 were 11% lower than in 2008 and approximately

35% below the 1990 level (Shell, 2009).  Shell’s ongoing efforts to reduce greenhouse gas emissions

should offset any incremental contribution from the Initial EP.

Water Quality.  Shell’s project will have some minor water quality impacts due to the

NPDES‐permitted discharge of drilling muds and cuttings, treated sanitary and domestic wastes,

excess cement, non‐contact cooling water, deck drainage, desalination unit brine, uncontaminated

fire water, and ballast water.  These effects are expected to be minor (localized to the area within a

few hundred meters of the discharge point), and temporary (lasting only hours longer than the

disturbance or discharge).  Any cumulative effects to water quality are expected to be negligible.

New Information.  The only new, potentially significant information available since preparation of the

multi‐lease‐sale EISs arises from the Macondo spill.  The Macondo spill caused short‐term, localized

air quality impacts, e.g., from evaporation of volatile hydrocarbons and ISB of floating oil.  Monitoring

by the USEPA (2010) has found levels of ozone and particulates ranging from “good” to “unhealthy

for sensitive groups” on USEPA’s Air Quality Index; these are at levels well below those that would

cause short‐term health problems.  The air monitoring conducted to date has not found any

pollutants at levels expected to cause long‐term harm (USEPA, 2010).  Satellite imagery indicates that

the surface slick from the Macondo spill did reach the lease area (ESRI, 2010).  However, based on

the information currently available, there is no reason to expect any change in air quality conditions

or cumulative impacts from those predicted in the multi‐lease‐sale EISs.  

The Macondo spill also resulted in water quality impacts.  In addition to the oil slick on the sea

surface, plumes of submerged oil droplets were produced when subsea dispersants were applied at

the wellhead (Camilli et al., 2010; Hazen et al., 2010; Joint Analysis Group, 2010a,b,c).  Satellite

imagery indicates that the surface slick from the Macondo spill did reach the lease area (ESRI, 2010),

and it is also possible that subsurface plumes could have affected water quality in or near the lease

area.  However, OSAT (2010) reported that, after August 2010, waters and sediments in the

deepwater Gulf of Mexico beyond 1.8 miles (3 km) from the Macondo wellsite were below USEPA

acute and chronic benchmarks for PAHs and were not hypoxic.  These observations indicate that

baseline environmental conditions in the lease area are unlikely to have been significantly altered by

the spill.  Prior to the incident, water quality in deep, offshore waters was expected to be good, with

low levels of contaminants (Kennicutt, 2000).  Based on the information currently available, there is

no reason to expect any change in water quality conditions or cumulative impacts from those

predicted in the multi‐lease‐sale EISs.

C.9.2 Cumulative Impacts to Biological Resources

The work planned in this Initial EP is limited in geographic scope and duration, and the impacts on

biological resources will be correspondingly limited.  
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Seafloor Habitats and Biota.  Effects on seafloor habitats and biota from discharges of drilling mud

and cuttings are expected to be minor and limited to a small area.  There are no areas that may

support high‐density deepwater benthic communities within 610 m (2,000 ft) of the wellsites, as

required by NTL 2009‐G40.  Soft bottom communities are ubiquitous along the northern Gulf of

Mexico continental slope, and the extent of benthic impacts during this project is insignificant

regionally.  As noted in the multi‐lease‐sale EISs, the incremental contributions of activities similar to

Shell’s proposed activities to the cumulative impacts is not significant (MMS, 2007b, page 4‐325).

Threatened, Endangered, and Protected Species.  Threatened and endangered species reasonably

likely to occur in the lease area include the sperm whale and five species of sea turtles.  Potential

impact sources include drilling rig and drillship presence including noise and lights; marine debris;

and support vessel and aircraft traffic.  Potential effects for these species would be limited and

temporary, and would be reduced by Shell’s compliance with all BOEMRE‐required mitigation

measures including NTLs 2007‐G03 and 2007‐G04.  No significant cumulative impacts are expected.

Coastal and Marine Birds.  Some birds may be attracted to offshore structures because of the lights

and the fish populations that aggregate around these structures.  Birds that frequent platforms may

be exposed to contaminants including air pollutants and routine discharges, but significant impacts

are unlikely due to rapid dispersion.  Shell’s compliance with NTL 2007‐G03 will minimize the

likelihood of debris‐related impacts on birds.  Support vessel and helicopter traffic may disturb some

foraging and resting birds; however, it is likely that individual birds would experience, at most, only

short‐term behavioral disruption.  Due to the limited scope and short duration of drilling activities,

collisions or other adverse effects are unlikely, and no significant cumulative impacts are expected.

Fisheries Resources.  Drilling rigs and drillships are known to be “fish‐attracting devices” such that

some species of epipelagic fishes may be attracted to the rig and potentially attract predators. These

short term effects are expected to be small given the isolated nature of the drilling rig or drillship and

would not be considered a significant impact on pelagic communities, fishery resources, or EFH.  

When the drilling rig or drillship is on‐site, these effects would be temporarily additive to those

associated with other exploration and production structures in the area, but would occur at low

levels such that the cumulative effect would be negligible.

Coastal Habitats.  Due to the distance from shore, routine activities are not expected to have any

impacts on beaches and dunes, wetlands, seagrass beds, coastal wildlife refuges, wilderness areas, or

any other managed or protected coastal area.  The support bases at Port Fourchon and Boothville are

not in a wildlife refuge or a wilderness area.  Support operations, including crew boats and supply

boats, may have a minor incremental impact on coastal habitats.  Over time with a large number of

vessel trips, vessel wakes can erode shorelines along inlets, channels, and harbors.  Impacts will be

minimized by following the speed and wake restrictions in harbors and channels.

New Information.  The only new, potentially significant information available since preparation of the

multi‐lease‐sale EISs arises from the Macondo spill.  The spill has resulted in impacts on biological

resources, including visibly oiled and/or dead birds, marine mammals, and sea turtles, as well as

oiling of coastal habitats from approximately the Texas/Louisiana border to the Florida panhandle.  

Another large spill could result in significant cumulative impacts to these resources.  However, for all

the reasons discussed in the Initial EP, Shell’s NTL 2010‐N06 response, the OSRP, and herein, the

likelihood of a catastrophic well control event resulting in significant amounts of oil in the water is

extremely remote.  Therefore, Shell’s proposed activities are not expected to result in any cumulative

impacts to biological resources affected by the Macondo spill, nor should they have any impact on

the previously conducted cumulative impact analyses.

Regarding deepwater benthic communities, the multi‐lease‐sale EISs (MMS, 2007a, 2008) concluded

that oil spills would be unlikely to affect benthic communities beyond the immediate vicinity of the

wellhead (i.e., due to physical impacts of a blowout) because the oil would rise quickly to the sea

surface directly over the spill location.  However, during the Macondo spill, subsurface plumes were

reported at a water depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the
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wellsites and persisting for more than a month (Camilli et al., 2010).  The subsurface plumes

apparently resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c).  This

observation is supported by Kujawinski et al. (2011) in their report that chemical components of

subsea dispersants used during the Macondo spill persisted for up to two months and were detected

up to 186 miles (300 km) from the wellsite at a water depth of 1,000 to 1,200 m (3,280 to 3,937 ft).  

However, estimated dispersant concentrations in the subsea plume were below levels known to be

toxic to marine life.  While the behavior and impacts of subsurface plumes are not well known, a

subsurface plume could contact the seafloor and affect benthic communities beyond the 300‐m (984‐

ft) radius estimated by MMS (2007a, 2008), depending on its extent, trajectory, and persistence.  This

contact could result in smothering and/or toxicity to benthic organisms.  The affected area would be

recolonized by benthic organisms over a period of months to years (NRC, 2003).

C.9.3 Cumulative Impacts to Socioeconomic Resources

The work planned in this Initial EP is limited in geographic scope and duration, and the impacts on

socioeconomic resources will be correspondingly limited.

Archaeological Resources.  MC 762 is on the list of leases with a high potential for historic shipwrecks.  

However, an archaeological assessment by C&C Technologies, Inc. (2008) indicated that none of the

sonar contacts in the lease area were interpreted as historic shipwrecks.  Also, the lease area is well

beyond the 60‐m (197‐ft) depth contour used by the BOEMRE as the seaward extent for prehistoric

archaeological site potential in the Gulf of Mexico.  Therefore, Shell’s operations will have no

cumulative impacts on historic shipwrecks or prehistoric archaeological resources.

Socioeconomic Resources.  The multi‐lease‐sale EISs analyzed the cumulative impacts of oil and gas

exploration and development in the lease area, in combination with other impact‐producing

activities, on commercial fishing, recreational fishing, recreational resources, historical and

archaeological resources, land use and coastal infrastructure, demographics, and environmental

justice (MMS, 2007b, pages 4‐359 to 4‐378).  The BOEMRE also analyzed the economic impact of oil

and gas activities on the Gulf States, finding only minor impacts in most of Texas, Mississippi,

Alabama, and Florida, more significant impact in parts of Texas, and substantial impact on Louisiana.

Shell’s proposed activities will have negligible cumulative impacts on socioeconomic resources.  

There are no IPFs associated with routine operations that are expected to affect public health and

safety, employment and infrastructure, recreation and tourism, land use, or other marine uses.  Due

to the distance from shore, it is unlikely that any recreational fishing activity is occurring in the

project area, and it is unlikely that any commercial fishing activity other than longlining occurs at or

near the project area.  The project will have negligible impacts on fishing activities.

New Information.  The only new, potentially significant information available since preparation of the

multi‐lease‐sale EISs is the Macondo spill.  The spill has resulted in impacts on commercial and

recreational fishing, recreation and tourism, employment, and public health and safety.  The

Macondo spill resulted in extensive fishery closures in the Gulf of Mexico, peaking at 34.8% of the

EEZ in the Gulf of Mexico (NMFS, 2010c).  The U.S. Travel Association has estimated the economic

impact of the Macondo spill on tourism across the Gulf Coast over a 3‐year period at $22.7 billion

(Oxford Economics, 2010).  Reported health impacts (e.g., among spill response and wildlife

rehabilitation workers) ranged from cuts and scrapes, to upper respiratory symptoms and heat stress,

to acute exposure to hydrocarbons or H2S (Centers for Disease Control and Prevention, 2010a,b;

Solomon and Janssen, 2010).  Most of these impacts were temporary in nature, although health

exposure of clean‐up workers could have longer‐lasting impacts.

However, for all the reasons discussed in the Initial EP, Shell’s NTL 2010‐N06 response, the OSRP, and

herein, the likelihood of a catastrophic well control event resulting in significant amounts of oil in the

water is extremely remote.  Therefore, Shell’s proposed activities are not expected to result in any

cumulative impacts to socioeconomic resources affected by the Macondo spill, nor should they have

any impact on the previously conducted cumulative impact analyses.
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D.  Environmental Hazards

D.1 Geologic Hazards

The shallow hazards assessment included in this Initial EP, based on the shallow hazards report by

GEMS (2003), concludes that the wellsites are free of any major geological hazards and are suitable

for the proposed activities.  See Initial EP Section 6a for supporting geological and geophysical

information.

D.2 Severe Weather

Under most circumstances, weather is not expected to have any effect on the proposed activities.  

Extreme weather, including high winds, strong currents, and large waves, was considered in the

design criteria for the drilling rig and drillship.  High winds and limited visibility during a severe storm

could disrupt communication and support activities (vessel and helicopter traffic) and make it

necessary to suspend some activities on the drilling rig or drillship for safety reasons until the storm

or weather event passes.  In the event of a hurricane, procedures as outlined in Shell’s Hurricane

Evacuation Plan would be adhered to.

D.3 Currents and Waves

A rig‐based acoustic Doppler current profiler will be used to continuously monitor the current

beneath the rig.  Metocean conditions such as sea states, wind speed, ocean currents, etc. will also

be continuously monitored.  Under most circumstances, physical oceanographic conditions are not

expected to have any effect on the proposed activities.  Strong currents (e.g., caused by Loop Current

eddies and intrusions) and large waves were considered in the design criteria for the drilling rig and

drillship.  High waves during a severe storm could disrupt support activities (i.e., vessel and helicopter

traffic) and make it necessary to suspend some activities on the drilling rig or drillship for safety

reasons until the storm or weather event passes.

E.  Alternatives

No formal alternatives were evaluated in this EIA.  However, various technical and operational

options, including the location of the wellsites and the selection of a drilling unit, were considered by

Shell in developing the proposed action.  There are no other reasonable alternatives to accomplish

the goals of this project.   

F.  Mitigation Measures

The proposed action includes numerous mitigation measures required by laws, regulations, and the

BOEMRE lease stipulations and NTLs.  The project will comply with all applicable Federal, State, and

local requirements concerning air pollutant emissions, discharges to water, and solid waste disposal.  

All project activities will be conducted under Shell’s OSRP and will include the measures described in

Initial EP Section 2j.  Additional pollution prevention measures, beyond those required by 30 CFR

Part 250, include the following:

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

meetings.  The discussion around no harm to people or environment is a key mindset.  All
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personnel are reminded daily to inspect work areas for safety issues as well as potential pollution

issues.

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

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

• Preventive maintenance of rig equipment includes visual inspection of hydraulic lines and

reservoirs on a routine scheduled basis.

• All pollution pans on rig are inspected daily.

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

fuel storage tanks.

• All used oil and fuel is collected and sent 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, and 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 are changed on annual basis.

• Spill prevention fittings are installed on all liquid take‐on hoses.

• Waste paint thinner is recycled on board with a solvent to further reduce hazards of shipping and

storage.

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

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

• Shell will use low sulfur fuel (0.05% by weight) to reduce air pollutant impacts.

• Use of a dynamically positioned rig and drillship (no anchors) and high resolution sonar for well

location planning will minimize the potential for barrel impact. Shell has prepared a BOEMRE‐

approved plan for “Waste Barrel Avoidance and Release Response in the Mississippi Canyon

Area” that applies to anchoring and other operations that could cause a disturbance of a seafloor

barrel.  The plan specifies a safe stand‐off distance from the waste barrels of 10 m (33 ft) and

requires that anchor locations be surveyed with an ROV to maximize barrel avoidance.  In the

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

specifies actions to be taken for the topside safety of personnel handling the equipment.  The

plan also outlines barrel impact reporting procedures.  

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

The EIA was prepared at the direction of Shell Offshore Inc. by its contractor, CSA International, Inc.  

Contributors included

• Sylvia Bellone (Regulatory Specialist, Shell Exploration & Production Co.);

• Lori Downs (Environmental Team Leader, Shell Exploration & Production Co.);

• Rob Kuehn (Environmental Engineer, Shell Exploration & Production Co.);

• Victoria Broje (Spill Response Specialist, Shell Global Solutions US Inc.);

• Steve Truchon (Environmental Ecologist, Shell Global Solutions US Inc.);

• Phil Smith (Incident Command Manager, Shell Exploration & Production Co.);

• Erling Westlein (Environmental Engineer, Shell Exploration & Production Co.);

• Tracy Albert (Regulatory Specialist, Offshore Technical Compliance LLC);

• Derek Newberry (Mars B Business Opportunity Manager, Shell Exploration & Production Co.);

• Robert Sloan (Mars B/West Boreas Subsurface Coordinator, Shell Exploration & Production Co.);

• Carlyle Kalloo (Senior Scientist, CSA International, Inc.);

• Neal Phillips, Ph.D. (Senior Scientist, CSA International, Inc.);  

• Deborah Fawcett (Project Scientist II, CSA International, Inc.);

• Stephen Viada (Senior Scientist, CSA International, Inc.);

• Keith VanGraafeiland (GIS/Remote Sensing Specialist, CSA International, Inc.); and

• Kim Dunleavy (Technical Editor, CSA International, Inc.).

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SECTION 19: Administrative Information

A. Exempted Information Description (Public Information Copies Only) 

The following attachments were excluded from the public information copies of this plan: 

1b. OCS Plan Information form – Bottom hole locations & proposed total depth 

2j. Proprietary data related to WCD (N06) 

3a. Geologic Description 

3b. Structure Contour Maps 

3c. Interpreted 2D or 3D seismic line(s) 

3d. Cross Section(s) 

3e. Shallow Hazards Report 

3f. Shallow Hazards Assessment – confidential data 

3g. High-Resolution Seismic Lines & Top Hole Progs 

3h. & 3i. Stratigraphic Column with Time vs. depth table 

B. Bibliography 

Shallow hazard Report No. 1188-1062 prepared by Fugro-McClelland, on April 26, 1988, and Report No. 0201-

1387 also prepared by Fugro-McClelland, on April 20, 1992.