UNITED STATES GOVERNMENT MEMORANDUM

To: Public Information (MS 5030)

Plans Section, Office of Field Operations (MS 5231)

Public Information copy of Exploration Plan

Control # - R-05177

Type - Revised Exploration Plan

Lease(s) - OCS-G31943 Block - 95 Walker Ridge Area

Operator - Shell Offshore Inc.

Subsea Wells A, B, C, D, and E

DRILLSHIP

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

should be addressed in an Environmental Assessment.

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

Michelle Griffitt

Plan Coordinator Description -

Rig Type - Subject: From: July 28, 2011

### 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 6747

T elex http://www.shell.com/eandp-en Email sylvia.bellone@shell.com

April 27, 2011 PUBLIC INFORMATION

Ms. Liz Peuler, Section Chief Bureau of Ocean Energy Management, Regulation and Enforcement

1201 Elmwood Park Boulevard New Orleans, LA 70123-2394

Attn: Plans Group MS 5231

SUBJECT: Revision to Exploration Plan N-9410 – Walker Ridge Block 95 OCS-G 31943, Offshore Louisiana

Gentlemen:

In compliance with 30 CFR 250.103 and NTLs 2008- G04, 2009-G27 and 2010-N06, giving Exploration Plan guidelines, Shell Offshore Inc (SOI) requests your approval of this Revised Exploration Plan requesting approval to drill Well Locations A, B, C, D & E.

The NTL 2010-06 Worst Case Blowout requirements fo r our Regional Oil Spill Response Plan’s highest exploration well was previously submitted October 26, 2010. The WCD in this Plan does not exceed that

total.

This Plan consists of a series of attachments desc ribing 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.

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

Sincerely,

Sylvia A. Bellone

## SHELL OFFSHORE INC.

REVISED EXPLORATION

PLAN N-9410

for

WALKER RIDGE BLOCK 95

OCS-G 31943



# PUBLIC INFORMATION

PREPARED BY:



## Sylvia A. Bellone Sr. Regulatory Specialist

504.728.7215

Sylvia.bellone@shell.com

### REVISONS TO Plan R-5177

Request Section of What Changed Date of Date Plan Response

5/12/11 Section 1 A Info about dry hole tree Description, Objectives & Schedule

Section 1, Plan Information BHL 5/13/11 From “A” (2 of 6)

Section 6A Chemosynthetic Communities Reference to Plan N-9410

Section 14E Corrected OCS Number Vicinity Map

6/7/11 Section 6A Chemosynthetic Communities Provided ESR maps 6/21/11 Provided revised ESR maps 6/28/11

7/12/11 Section 9 Oil Spill Info and Revised OSRP comparison 7/13/11 9 iv Regional OSRP numbers and filing datesREVISED EXPLORATION PLAN (R-5177)

WALKER RIDGE Area

BLOCK 95

Table of Contents

1. Plan Contents

2. General Information

3. Geological and Geophysical

4. Hydrogen Sulfide - H 2 S

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 InformationSECTION 1: PLAN CONTENTS

A. DESCRIPTION, OBJECTIVES & SCHEDULE

This Revised Exploration Plan (EP/Plan) with appendices, including an Environmental Impact Analysis (EIA) found in Section 18, describes the drilling activities Shell Offshore Inc. (Shell) plans to conduct with respect to Lease OCS-G 31943 located in Walker Ridge block 95. Wells A through E were approved in Plan N-9410 September 22, 2009. The wells were never drilled. This Revised Plan will provide updated information for this activity.

Shell’s Plan, as detailed in its EP, is to use a drillship, the M/V Noble Globetrotter or equivalent (the “Rig”). The initial drilling activities are planned to commence on or about January 1, 2012 depending on rig arrival. The drilling is expected to take approximately 198 days fo r the first well and approximately 165 days for the other wells. The timeframe to complete the initial drilling activities is an estimate based on the best available information regarding downhole conditions likely to be enco untered while drilling each well and not intended to be a limitation. The timeframe for drilling the first well w ill further define the timing for further development of the prospect. Once the well(s) are drilled, a dry hole tree will be installed. Shell will complete and commence production under a separate DOCD.

The Rig is a DP drillship and is equipped with state-of-the -art drilling and well control equipment. The Rig will comply with the requirements in the Interim Final Rules. The drilling activities will be supported by the support vessels and aircraft as well as onshore support facilities as listed in Sections 14 and 15 of the EP. Shell has employed or contracted with trained personnel to carry ou t its exploration activities. Shell is committed to local hire, local contracting and local purchasing to the maximu m extent possible. Shell personnel and contractors are experienced at operating in the Gulf of Mexico and are well versed in all Federal and State laws regulating operations. Shell’s employees and contractors share Sh ell’s deep commitment to operating in a safe and environmentally responsible manner.

Shell, through its parent and affiliate corporations, has ex tensive experience safely exploring for oil and gas in the Gulf of Mexico. Shell will draw upon this experience in organizing and carrying out its planned WR 95 drilling program. Shell believes that the best way to manage bl owouts is to prevent them from happening. Significant effort goes into the design and execut ion of wells and into building and maintaining staff competence. In the unlikely event of a spill, Shell’s Regional OSRP (October 201 0) is designed to contain and respond to a spill that

meets or exceeds the WCD detailed in section 9 of this EP. The WCD does not take into account potential flow mitigating factors such as well bridging, obstructions in wellbore, reservoir barriers, or early intervention. We

continue to invest in Research and De velopment (R&D) to improve safety and reliability of our well systems. All operations will be conducted in accordance with applic able federal and state laws, regulations, and lease and permit requirements. Shell will have trained personnel and monitoring programs in place to ensure such compliance.

B. LOCATION

See attached Maps.C. RIG SAFETY AND POLLUTION FEATURES :

The rig (Noble Globe Trotter or similar) will comply with a ll of the regulations of the American Bureau of Shipping (ABS), International Maritime Organization (IMO) and the United States Coast Guard (USCG). All drilling operations will be conducted under the provisions of 30 CF R, Part 250, Subpart D, and other applicable regulations and notices, including those regarding the avoidance of potential drilling hazards and safety and pollution prevention control. Such measures as inflow detection and well control, monitoring for loss of circulation and seepage loss, and casing design will be our primary safe ty measures. Primary pollut ion prevention measures are contaminated and non-contaminated drain system , mud drain system, and oily water processing.

DRAIN SYSTEM POLLUTION FEATURES

Drains are provided on the Rig in all spaces and on all decks where water or oil can accumulate. The drains are divided into two categories, non-contaminated and contam inated. All deck drains are fitted with a removable strainer plate to prevent debris entering the system.

Deck Drainage from rainfall, Rig washing, deck washing, and runoff from curbs and gutters, including drip pans and work areas, are discharged depending on if it comes in contact with the contaminated or non-contaminated areas of the Rig.

1) Non-contaminated Drains

Non-contaminated drains are designated as drains that under normal circumstances do not contain hydrocarbons, and can be discharged directly overboard. These are mostly located around the main deck and outboard in places where it is unlike ly that hydrocarbons will be found.

Drains within 50 feet of a designated chemical stor age area which uses the weather deck as a primary containment means shall be designated “normally plugged.” An adequate number of drains around the rig shall be designated as “normally open” to allow run-off of rain water. Normally open drains shall have a plug located in a conspicuous area near the drain which can be easily installed in the event of a spill.

The rig’s drain plug program consist at a minimum of a weekly check of all deck drains leading to the sea to verify that their status is as designated If normally open they shall verify that the drain is open and that the plug is available in the area. If normally closed they sha ll verify that the plug is securely installed in the drain.

In the event a leak or spill is observed, the event shall be contained (drain plug installation and / or spill kit deployment as appropriate) and reported immediately.

Rig personnel shall ensure that the perimeter kick-plates on weather decks are maintained and drain plugs are in place as needed to ensure a proper seal.

2) Contaminated Drains

Contaminated drains are designated as drains that co ntain hydrocarbons and cannot be discharged overboard. When oil-based mud is used for drilling it will be collected in portable tanks and sent to shore for processing.

3) Mud Drain System

None4) Oily Water Processing

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

content is < 15 ppm. The separated oil is pumped to a dirty o il tank and has to be sent ashore for disposal. On board the MODU an oil record log has to be kept ac cording to instructions included in the log. Any and all pollution pans are subjected to a sheen test before being pumped out. If the water passes the sheen test then it is pumped over board. If it does not pass th e sheen test then the water/oil mixture is pumped to a dirty oil tank and sent to shore for disposal. All waste oil that is sent in to be disposed of is recorded in the MODU’s oil log book.

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

5) Lower Hull Bilge System

• The main bilge system is designed to drain th e pontoons. There are Goulds electrically driven, self priming centrifugal pumps - one for each main pump room. The aux pumps can be pump out with the bilge pump but has to be line up manually from the main pump room. • Bilge water is pumped overboard after a sheen test has been completed. • The pontoon bilge pumps are operable from the Brid ge, and have audible and visual bilge alarms set for high and low levels. • Portable submersible pumps are carried onboard the rig to service all column void spaces and are also used for emergency bilge pump in the event of the main pump room flooding. • Alternate means of pumping the bilges in each pontoon pump room include the use of: • The ballast system emergency bilge valve which is operated from the control panel. • Portable submersible pumps • Emergency bilge suction line connected directly to the ballast manifold. (Main Pump rooms only)

The Bilge pumps are manual/automatic type pumps. They are equipped with sensors that give a high and a high high alarm. They are set to a point at which th e water gets to a certain point they will automatically turn on to pump water out in order to keep flooding under control. The pumps are also capable of being put in manual mode in which they can be turned on by hand.

6) Emergency Bilge System

Main ballast pumps may also be used for emergency bilge pumping directly from the pump rooms via remotely actuated direct bilge suction valves on the ballast system. These valves will operate in a fully flooded compartment. The ballast pumps can be supplied from the emergency switchboard.

7) Oily Water Drain/Separation System

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

overboard until oil content is < 15 ppm. The separated oil is pumped to a dirty oil tank and has to be sent ashore for disposal. On board all drilling Units, an oil record log has to be kept according to instructions included in the log. The rig floor has two skimmer ta nks and each is subjected to a sheen test before pumping overboard to ensure environmental safety. A ll three anchor winch windlasses have skimmer tanks and are subjected to sheen test s before discharge as well.

8) Drain, Effluent and Waste Systems

• The Rig’s drainage system is designed in line with our environmental and single point discharge policies. Drains are either hazardous, i.e. from a hazardous ar ea as depicted on the Area Classification drawings,

or non-hazardous drains fr om nonhazardous areas. • To prevent migration of hazardous materials and flammable gas from hazardous to non-hazardous areas, the drainage systems are segregated. • The Rig drainage systems tie into oily water separators that take out elements in the drainage that could harm the environment. This is part of Noble’s initiative to be good stewards of the environment. The oily water separators divide the dr ainage system into these sections:9) Rig Floor Drainage

The Rig floor has been outfitted with a Facet In ternational MAS 34-3 separa tor. The separator has coalescent plates that remove the solids from the dr ainage, and the remaining drainage goes to a skimmer

tank. From the skimmer tank it is drained to one of th e column dirty oil tank systems where it is then sent through 2 separators and cleaned further to reduce oil content to less than 15 ppm.

10) Columns #3 & 4

The drains on the decks and machinery spaces are separa ted at mid ship and directed to either the #3 or #4 columns. The separators in these columns go throug h three cycles of circulation and remove oil to less than 15ppm, then discharge the clean product to sea.

11) Main Engine Rooms

• The engine rooms have their own drainage and hand ling system. The engine rooms are outfitted with a dirty oil tank and the drainage in the tank is pr ocessed through the separator, the waste from the separator goes back to the dirt y oil tank and the clean water (less than 15ppm) goes overboard. • The locations and models of the separators are as follows:

• Column #3 – Westfalia WSD-18

• Column #4 – Westfalia WSD-18

• Drill Floor – Facet International MAS 34-3

12) Helideck Drains

The helideck has a dedicated drainage system around its perimeter to drain heli-fuel from a helicopter incident. The fuel can be diverted to the designated heli fuel reco very tank which is located under the Helideck structure.

Operating configurations are as follows:

3⁄4 The overboard piping valves and hydrocarbons take on valves are closed and locked. To unlock overboard or take on valves a permit has to be filled out.

3⁄4 The oily water collection tank overflow valve is closed.

3⁄4 The drill floor drains are lined-up to the drill fl oor skimmer tank. The Skimmer tanks have a high alarm which sounds by means of an air horn. Before tanks are pumped out a sheen test is performed. Water is pump out the skimmer tanks down the shunt line. Oil containment side is pumped out into 550 gal tote tanks.

3⁄4 The BOP test area drains are norm ally lined-up to drain overboard.

3⁄4 The oily water separator continuously circulates the oily water collectio n tank. Waste oil is discharged into the waste oil tank and oily water is re-circulated back into the oily water collection tank. Clean water is pumped overboard, which is controlled/monitored by the oil content detector, set at 15 ppm.

3⁄4 The solids control system is capable of being isolated for cuttings collection.

3⁄4 The bilge system is normally pumped directly over board after a sheen test has been performed.

3⁄4 The engine dirty oil sump can be drained down in Port column oily water separator which discharges water overboard from the water side an d oil being pumped out into a 550 gal tote tank oil containment side. There is a high audible alarm on the ballast control panel.D. Storage Tanks :

Type of Storage Tank Type of Tank Number of Total Fluid Facility Capacity (bbls) Tanks Capacity (bbls) Gravity (API)

Fuel oil MODU 2652 1 2652 No. 2 diesel Fuel oil MODU 1,743 1 1743 No. 2 diesel

Fuel oil MODU 5767 1 5767 No. 2 diesel

Fuel oil MODU 4399 1 4399 No. 2 diesel

Fuel oil MODU 2652 1 2652 No. 2 diesel

Fuel oil MODU 3250 1 3250 No. 2 diesel

Fuel oil MODU 4399 1 4399 No. 2 diesel

Fuel oil MODU 2618 1 2618 No. 2 diesel

Fuel oil MODU 115 4 460 No. 2 diesel

Fuel oil MODU 129 4 516 No. 2 diesel

E. Pollution Prevention Measures

Pursuant to NTL No. 2008-G04 the propos ed operations covered by this EP do not require Shell to specifically address the discharges of oils and grea ses from the Rig during rainfall or routine operations. Nevertheless, Shell has provided this information as part of its response in 1(c) above.

F. Additional Measures

3⁄4 HSE (health safety and environment) are the primary topics in pre-tour and pre-job safety meetings. The discussion around no harm to people or environment is a key mindset. All personnel are reminded daily to inspect work areas for safety issues as well as potential pollution issues.

3⁄4 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.

3⁄4 Preventive Maintenance of Rig equipment includes visual inspection of hydraulic lines and reservoirs

on routine scheduled basis.

3⁄4 All pollution pans on Rig are inspected daily.

3⁄4 Containment dikes are installed around all oil contai nment, drum storage areas, fuel vents, and fuel storage tanks.

3⁄4 All used oil and fuel is collected and sent in for recycling.

3⁄4 Every drain on the Rig is assigned a number on a chec klist. The checklist is used daily to verify drain plugs are installed.

3⁄4 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.

3⁄4 The Rig is involved in a recycling program for ca rdboard, plastic, paper, glass, and aluminum.

3⁄4 Fuel hoses and SBM are changed on annual basis.

3⁄4 TODO spill prevention fittings are installed on all liquid take on hoses.

3⁄4 Waste paint thinner is recycled on board with a solvent still to reduce hazard of shipping and storage.

3⁄4 All equipment on board utilizes Envirorite hydraulic fluid as opposed to hydraulic oil.

3⁄4 Shell has obtained ISO14001 certification.

3⁄4 Shell uses low sulfur fuelU. S. Department of the Interior OMB Control Number: 1010-0049 Minerals Management Service OMB Approval Expires: August 31, 2006 

### OCS PLAN INFORMATION FORM

General Information

Type of OCS Plan: X Exploration Plan (EP) Deve lopment 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 31943 Area: Walker Ridge Block(s): 95 Project Name (If Applicable): NA

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

Boothville Distance to Closest Land (Miles):

156



### Description of Proposed Activities (Mark all that apply)



### X Exploration drilling Development drilling

Well completion Installation of production platform

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

Installation of caisson or platform as well protec tion structure Installation of satellite structure

Installation of subsea wellheads a nd/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? Yes X No

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

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

Do you propose any activities that may disturb an MMS-des ignated high-probability arch aeological area? Yes X No

Have all of the surface locations of your proposed activities been previously revi ewed and approved by MMS?* X Yes* No



### Tentative Schedule of Proposed Activities

Proposed Activity Start Date End Date No. of Days

Drill Well A 1/1/2012 7/17/2012 198

Drill Well B 1/1/2013 6/15/2013 165

Drill Well C 1/1/2014 6/15/2014 165

Drill Well D 1/1/2015 6/15/2015 165

Drill Well E 1/1/2016 6/14/2016 165

*The SLs for these wells were reviewed and approved in Plan N-9410



### Description of Drilling Rig Description of Production Platform

Jackup X Drillship Caisson Tension leg platform

Gorilla Jackup Platform rig Well protector Compliant tower

Semisubmersible Submersible Fixed platform Guyed tower

DP Semisubmersible Other (A ttach Description) Subsea mani fold Floating production system

Drilling Rig Name (If Known): Noble Globe Trotter or similar Spar Other (Attach Description)



### Description of Lease Term Pipelines

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



### N/A



# MMS Form MMS-137 (August 2003) Page 1 of 6 PUBLIC INFORMATION

### 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 struct ure, reference previous name): A Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 31943

Area Name Walker Ridge

Block No. 95

Blockline Departures (in feet) N/S Departure: 7122’ FNL

E/W Departure: 5625’ FEL

Lambert X-Y

coordinates X: 2101095

Y: 9750318

Latitude/ Longitude Latitude 26.86322929

Longitude -91.58656019

TVD (Feet): MD (Feet): Water Depth (Feet): 5848’



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

Anchor Name

or No. Area Block X Coordinate Y C oordinate 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 th e information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of Informa tion 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 th e form. Direct comments rega rding 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) Page 2 of 6 PUBLIC INFORMATION

### 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 struct ure, reference previous name): B Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 31943

Area Name Walker Ridge

Block No. 95

Blockline Departures (in feet) N/S Departure: 7531’ FNL

E/W Departure: 4079’ FEL

Lambert X-Y

coordinates X: 2102641

Y: 9749909

Latitude/ Longitude Latitude 26.86205653

Longitude -91.58183200

TVD (Feet): MD (Feet): Water Depth (Feet): 5833’



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

Anchor Name

or No. Area Block X Coordinate Y C oordinate 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 th e information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of Informa tion 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 th e form. Direct comments rega rding 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) Page 3 of 6 PUBLIC INFORMATION

### 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 struct ure, reference previous name): C Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 31943

Area Name Walker Ridge

Block No. 95

Blockline Departures (in feet) N/S Departure: 3717’ FNL

E/W Departure: 1035’ FEL

Lambert X-Y

coordinates X: 2105685

Y: 9753723

Latitude/ Longitude Latitude 26.87245572

Longitude -91.57236315

TVD (Feet): MD (Feet): Water Depth (Feet): 5841’



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

Anchor Name

or No. Area Block X Coordinate Y C oordinate 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 th e information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of Informa tion 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 th e form. Direct comments rega rding 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) Page 4 of 6 PUBLIC INFORMAITON

### 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 struct ure, reference previous name): D Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 31943

Area Name Walker Ridge

Block No. 95

Blockline Departures (in feet) N/S Departure: 7805’ FNL

E/W Departure: 5427’ FEL

Lambert X-Y

coordinates X: 2101293

Y: 9749635

Latitude/ Longitude Latitude 26.861344111

Longitude –91.585976207

TVD (Feet): MD (Feet): Water Depth (Feet): 5949’



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

Anchor Name

or No. Area Block X Coordinate Y C oordinate 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 th e information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of Informa tion 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 th e form. Direct comments rega rding 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) Page 5 of 6 PUBLIC INFORMATION

### 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 struct ure, reference previous name): E Subsea Completion

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

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 31943

Area Name Walker Ridge

Block No. 95

Blockline Departures (in feet) N/S Departure: 8278’ FNL

E/W Departure: 4144’ FEL

Lambert X-Y

coordinates X: 2102576

Y: 9749162

Latitude/ Longitude Latitude 26.86000335

Longitude –91.58205701

TVD (Feet): MD (Feet): Water Depth (Feet): 5843’



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

Anchor Name

or No. Area Block X Coordinate Y C oordinate 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 th e information to facilitate our review and data entry for OCS plans. We will protect proprietary data according to the Freedom of Informa tion 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 th e form. Direct comments rega rding 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) Page 6 of 6 PUBLIC INFORMAITONSECTION 2: GENERAL INFORMATION

A. Application and Permits

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

need to be obtained.

B. Drilling Fluids
See Table 7A

C. Production

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

of DOCDs.

D. Oil Characteristics

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

case of DOCDs.

E. New Or Unusual Technology

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

activities in this EP.

F. Bonding

The bond requirement for the activities proposed in this SEP are satisfied by an area-wide bond furnished and maintained according to 30 CFR Part 256, subpart I; NTL No. 2000-G16, Guideline for General Lease Surety Bonds;” and National NTL No. 2003-N06, “Supplemental Bond Procures.”

G. Oil Spill Financial Responsibility (OSFR)

Shell Offshore Inc (SOI), BOEMRE Operator Number 0689, has demonstrated oil spill financial responsibility for the facilities proposed in the EP according to 30 CFR Part 253, and NTL No. 2008-N05, “Guidelines for Oil Spill Financial Responsibility for Covered Facilities.”

H. Deepwater well control statement

Shell Offshore Inc (SOI), BOEMRE Operator Number 0689, has the financial capability to drill a relief well and conduct other emergency well control operations.

I. Suspension of Production

Information regarding Suspension of Production is not included in this EP as such information is only necessary in the case of DOCDs.J. Blowout scenario

Summary

This Section 2j was prepared by Shell Offshore Inc. (She ll) pursuant to the guidance provided in the Bureau of Ocean Energy Management, Regulation and Enforcement’s (BOEMRE) Notice to Lessees (NTL) No. 2010- N06 with respect to blowout and worst case discharge scenario descriptions.

Shell focuses on an integrated, three-pronged approach to a blowout, including prevention, intervention /containment, and recovery. Shell believes that the best way to manage blowouts is to prevent them from happening. Significant effort goes into the design and execution of wells and into building and maintaining staff competence. Shell continues to invest independ ently in Research and Development (R&D) to improve safety and reliability of our well systems. Shell intends to comply with all applicable laws, regulations, rules

and Notices to Lessees.

Shell is investing in R&D to improve containment system s. As outlined in Shell’s Oil Spill Response Plan (OSRP), and detailed in EP Section 9a (ii), Shell has co ntracts with Oil Spill Removal Organizations (ORSOs) to provide the resources necessary to respond to this Worst Case Discharge (WCD) scenario.

The WCD blowout scenario for Yucatan North is calculated for the WR-95 C location penetration of the Wilcox Formation and based on the guidelines outlined in NTL No. 2010-N06 along with subsequent Frequently Asked Questions (FAQ). Shell has submitted MC-391 C as the new worst-case scenario to the BOEMRE for inclusion in our Regional OSRP. In the unlikely event of a spill, Shell’s Regional OSRP (October 2010) is designed to contain and respond to a spill that exceed s this WCD. This WCD does not take into account potential flow mitigating factors such as well bridging, obstructions in wellbore, reservoir barriers, and early intervention including containment capabilities.

Uncontrolled blowout (volume first day) 99,000 bbls.

Uncontrolled blowout rate (first 30-days average daily rate) 79,000 bopd Duration of flow (days) based on relief well 211 days

Total volume of spill (bbls) for 211 days 15 MMBO

Table 1. Yucatan North Worst Case Discharge Summary

The green-field exploration prospect Yucatan Nort h is located approximately 135 nautical miles southsouthwest of the nearest Louisiana shoreline in the Gulf of Mexico (GOM), in water depths of approximately 5800 feet (ft) across the prospect. The structural co mponent of the target is defined by a three-way culmination against base-salt/salt weld that is approxim ately 2 miles long by 3 miles wide, with the crest of the objective near 28,000 ft subsea (SS). In ear ly 2009, Anadarko announced their discovery (Shenandoah WR52#1BP2 OCS G-25232) in the Wilcox Formation in Walker Ridge OCS block 52 approximately 5 miles to

the northeast of Yucatan North. The Shenandoah an d Yucatan North prospects share a common structural saddle at the Wilcox Formation stratigraphic level. Sh ell obtained all the well data collected from the Shenandoah wellbore, and our WCD calculations for Yu catan North presented in this document incorporate this offset well data. The only objective interval with predicted flow potentia l is the Wilcox Formation reservoir of Eocene-Paleogene age.

1) Purpose Pursuant to 30 CFR 250.213(g), 250.219, 250.250, and NTL No. 2010-N06, this document provides a blowout scenario description, further information regarding an y potential oil spill, the assumptions and calculations

used to determine the WCD and the measures taken to 1) enhance the ability to prevent a blowout and 2) respond and manage a blowout scenario if it were to occur. These ca lculations are based on best technical estimates of subsurface parameters that are derived from the offset Shenandoah well data, additional regional Wilcox Formation offset well data, and seismic data. These parameters are better than or consistent with the estimates used by Shell to justify the invest ment. Therefore, these assumed parameters were used to calculate the WCD. They do no t reflect probabilistic estimates.2) Background

This attachment has been developed to document the additional inform ation requirements for Exploration Plans as requested by NTL No. 2010-N06 in response to the explosion and sinking of the Mobile Offshore Drilling Unit (MODU) Deepwater Horizon and the resultin g subsea well blowout and recovery operations of the exploration well at the MC-252 Macondo location.

3) Information Requirements

a) Blowout scenario

All five locations in the approved Yucatan North EP were assessed for WCD. The WR-95 well from the approved C location represents the highest flo w potential. The C well penetrates the Wilcox Formation reservoir as outlined in the Geologic al and Geophysical Information Section of the Supplemental EP using a subsea wellhead system, conductor, surface and intermediate casing program, and using a DP drillship with a marine riser and subsea blowout preventer (BOP). A hydrocarbon influx and a well control event are modeled to occur from the Wilcox Formation reservoir. The simulated blowout modeled results in unrestricted flow from the well at the seafloor, which represents the WCD (no restrictions in wellbor e, failure/loss of the subsea BOP, and a blowout to the seabed).

b) Estimated flow rate of the potential blowout

Category EP

Type of Activity Drilling

Facility Location (area/block) WR-95

Facility Designation MODU

Distance to Nearest Shoreline (Nautical miles) 135

Uncontrolled blowout (volume first day) 99,000 bbl

Uncontrolled blowout rate (first 30-days average daily rate) 79,000 bopd

Table 2. Estimated Flow Rates of a Potential Blowout

c) Total volume and maximum duration of the potential blowout

Duration of flow (days) 211 days total duration to drill relief well (14 rig mob, 4 transit, 151 spud to base Wilcox Fm., 42 ranging).

Total volume of spill (bbls) 15 MMBO based on 211 days flowing.

Note: From CMG numerical simulation model

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 is killed in a potential blowout further demons trates this decline. At very short times, e.g. during the first 24 hours, the pressure profile in the reservoir changes from the moment when a well first starts flowing to a pseudo-s teady state pressure profile with time, and as a result the rate declines. At somewhat longer time scales, effects such as reservoir voidage and the impact of boundaries can cause the rate to drop continuously with production. Simulation and material balance

models can include these effects and form the basis of the NTL No. 2010-N06 calculations for 24- hour and 30-day rates as well as maximum duration volumes.d) Assumptions and calculations used in dete rmining the worst case discharge (Proprietary):

Omitted from Public Information Copies

e) Potential for the well to bridge over

Mechanical failure/collapse of the borehole in a blowout scenario is influenced by several factors
including in-situ stress, rock strength and fluid velo cities at the sandface. Based on the nodal analysis
and reservoir simulation models outlined above, a seabed blowout would crea te a high drawdown at

the sand face. Given the substantial fluid velociti es inherent in the worst case discharge, and the

scenario as defined where the formation is not su pported by a cased and cemented wellbore, it is
possible that the borehole may fa il/collapse/bridge over within the span of a few days, significantly
reducing the outflow rates. However, this WCD scenario does not include any bridging.

f) Likelihood for intervention to stop the blowout.

Safety of operations is our top priority. Maintainin g well control at all times to prevent a blowout is the key focus of our operations. Our safe drillin g record is based on our robust standards, conservative well design, prudent operations practi ces, competency of personnel, and strong HSE focus. Collectively, these constitute a robust system making blowouts extremely rare events.

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

event is via intervention with the BOP attached to the well. There are built in redundancies in the BOP system to allow activation of selected componen ts with the intent to seal off the well bore. As a minimum, the Shell contracted rig fleet in the GO M will have redundancies meeting the Interim Final Drilling Safety Rule with respect to Remotely Op erated Vehicle (ROV) hot stab capabilities, a deadman system, and an autoshear system.

Additionally the Noble Globetrotter (dynamically posi tioned Drillship) will consist of 2 – 10K annulars, 4 – 15K drill pipe rams, 1 – 15K casing shear, and 1 – 15K CVX shear ram. The Globetrotter is also equipped with a deadman system and an autoshear system.

Containment: The experience of gaining control over the Macondo well has resulted in a better understanding of the necessary equipment and systems for well containment. As a result, industry and government are better equipped and prepared to day to contain an oil well blowout in deepwater (See page 17 of the Decision Memorandum dated Octo ber 1, 2010). Shell is further analyzing these advances and incorporating them into its comprehe nsive approach to help prevent and, if needed, control another deepwater control incident. Pursuant to NTL No. 2010-N10 Shell will provide a dditional information regarding our containment capabilities in a subsequent filing.

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

Blowout intervention can be conducted from an ROV equipped vessel, the existing drilling rig or from another drilling rig. Shell has an active portfolio of well operations in the GOM which will be supported by a total of four to six MODU rigs in 2011 – 2015 timeframe. The dynamically positioned rigs under contract, the Noble Danny Adkins, Globetro tter, and the Bully 1, will be the preferred rigs for blowout intervention work. However, moored rigs can also be used in some scenarios. Additionally, in the event of a blowout, there is the distinct possibility that other non-contracted rigs

in the GOM could be utilized whether for increased ex pediency or better suitability. All efforts will be made at the time to secure the appropriate rig. She ll’s current contracted rigs capable of operating at Yucatan North water depths and reservoir depths without constraints are in the following table:

### Rig Name Rig Type

Noble Danny Adkins dynamically positioned

semisubmersible

Bully #1* dynamically positioned
Drillship

Noble

Globetrotter* dynamically positioned
Drillship

Deepwater Nautilus moored semisubmersible

Noble Jim Thompson moored semisubmersible

Table 4. Shell Contracted Rigs Capable at Yucatan North



### .

Above are current as of April 2011. Future m odifications may change the rig’s capability.

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

*Bully 1 estimated arrival January 2012. Globetrotter estimated arrival Dec. 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. Table 4 lists the Shell contracted rigs capa ble of operating at Yucatan North. It is expected to take an average of 14 days to safely secure the well that the rig is working on up to the point the rig departs location, and an additional 4 days tran sit to mobilize to the relief well site depending on distance to the site. The relief well will take appr oximately 151 days to drill down to the last casing string above the blowout zone, plus approximately 42 days for precision rangin g activity to intersect
the blowout well bore. Total time to mobilize and drill a relief well would be 211 days for the

Yucatan North wells.

If a moored rig is chosen to conduct the relief we ll operations, anchor handlers would be prioritized to prepare mooring on the relief well site while the ri g is being mobilized. This mooring activity is not expected to delay initiation of relief well drillin g operations. Shell has three deepwater anchor handlers, the Laney, Dino, and Ross Chouest, on lo ng term contract to su pport its moored rigs.

It is not possible to drill relief wells from any ex isting platforms as there are none in the region.

i) Measures proposed to e nhance ability to prevent blowout and to reduce likelihood of a

blowout.

Shell believes that the best way to manage blowou ts is to prevent them from happening. Detailed below are the measures employed by Shell with the goal of no harm to people or the environment. The Macondo incident has highlighted the importance of these practices. The lessons learned from the investigation are, and will continue to be, incorporated into our operations.

Standards: Shell’s well design and operations adhere to internal corporate standards, the Code of Federal Regulations, and industry standards. A robu st management of change process is in place to handle un-defined or exception situations. Ingrai ned in the Shell standards for well control is the philosophy of multiple barriers in the well design and operations on the well.

Risk Management: Shell believes that prevention of major incidents is best managed through the systematic identification and mitigation process (Saf ety Case). All Shell contracted rigs in the GOM have been operating with a Safety Case and will cont inue to do so. A Safety Case requires both the owner and contractors to systematically identify th e risks in drilling operations and align plans to mitigate those risks; an alignment which is critical before drilling begins.Well Design Workflow: The Well Delivery Process (WDP) is a rigorous internal assurance process with defined decision gates. The WDP leverages functional experts (i nternal and external) to examine the well design at the conceptu al and detailed design stages for robustness before making a recommendation to the management review board. Sh ell’s involvement in global deepwater drilling, starting in the GOM in the mid-1980’s, provides a significant depth and breadth of internal drilling and operational expertise. Third party vendors and rig contractors are involved in all stages of the planning, providing their specific expertise. A Drill the Well On Paper (DWOP) exercise is conducted with rig personnel and vendors involved in execution of the well. This forum communicates the well plan, and solicits input as to the safety of the plan and procedures proposed.

Well and rig equipment qualification, certification, and quality assurance: All rigs will meet all applicable rules, regulations, and Notice to Lessees. Shell works closely with rig contractors to ensure proper upkeep of all rig equipment, which me ets or exceeds the strictest of Shell, industry, or regulatory requirements. Well tangibles are govern ed by our internal quality assurance/control standards and industry standards.

MWD/LWD/PWD Tools: Shell intends to use these tools at Yucatan North. The MWD/LWD/PWD tools are run on the drill string so that data on subsurface zones can be collected as the well advances in real time instead of waiting until the drill string is pulled to run wireline logs. Data from the tools are monitored and interpreted real time against prognosis to provide early warning of abnormal pressures to allow measures to be taken to progress the well safely.

Mud Logger: Mud-logging personnel continually monitor returning drilling fluids for indications of hydrocarbons, utilizing both a hot wire and a gas chromatograph. An abrupt increase in gas or oil carried in the returning fluid can be an indication of an impending kick. The mud logger also monitors drill cuttings returned to the surface in the drilling fluid for changes in lithology that can be an indicator that the well has penetrated or is about to penetrate a hydrocarbon-bearing interval. Mud logging instruments also monitor penetration rate to provide an early indication of drilling breaks that

show the bit penetrating a zone that could contain hydr ocarbons. The mud logging personnel are in

close communication with both the offshore drillin g foremen and onshore Shell representative(s) to report any observed anomalies so appropriate action can be taken.

Remote Monitoring: The Real Time Operating Center has been used by Shell to complement and support traditional rig-site monito ring since 2003. Well site operations are monitored 24/7 virtually by onshore teams consisting of geoscientists, petrophy sicists, well engineers, and monitoring specialists.

The same real time well control indicators moni tored by the rig personnel are watched by the monitoring specialist for an added layer of redundancy.

Competency and Behavior: A structured training program for Well Engineers and Foremen is practiced, which includes internal professional examinations to verify competency. Other industry training in well control, such as by 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, pre-job analysis, behavior based safety, DWOPs, audits), management HSE involvement and enforcement (e.g. compliance to life saving rules) have created a strong safety culture in our operations.

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

The response to a blowout is contained in our Well Control Contingency Plan (WCCP) which is a specific requirement of our internal well control standards. The WCCP in turn is part of the wider emergency response framework within Shell that a ddresses the overall organization response to an emergency situation. Resources are dedicated to th ese systems and drills are run frequently to test preparedness (security, medical, oil spill, and hu rricane). This same framework is activated and tested during hurricane evacuations, thereb y maintaining a fresh and responsive team.The WCCP specifically addresses implementing acti ons at the emergency site that will ensure personnel safety, organizing personnel and thei r roles in the response, defining information requirements, establishing protocols to mobilize sp ecialists, pre-selecting sources, and developing mobilization plans for personnel, material and services for well control procedures. The plan references individual activity checklists, a roster of equipment and services, initial information gathering forms, a generic description of relief we ll drilling, strategy and guidelines, intervention techniques and equipment, site safety mana gement, exclusion zones, and re-boarding.

As set forth in 3f of this document, Shell is cu rrently analyzing recent advances in containment technology and equipment and will incorporate them as they become available.

k) Arrangements for drilling a relief well

The size of the Shell contracted rig fleet in th e 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 thei r active roles elsewhere. Resources from other operators can also be leveraged should the need arise. Generally, relief well plans will mirror the blowout well, incorporating any learning on well design based on root cause analysis of the blowout. A generic relief well description is outlined in the WCCP.

l) Assumptions and calculations used in approved or proposed OSRP

Shell has submitted MC-391 C (Appo mattox) as the new exploratory worst-case scenario to the BOEMRE on 10-26-10 (plan code S7444) fo r 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 volumes, from small operational spills up to and including the WCD from an exploration well blowout. Shell’s program is developed to fully satisfy federal oil spill planning regulations. The Regional OSRP pres ents specific information on the response program that includes a description of personnel and equi pment mobilization, the incident management team organization, and the strategies and tactics used to implement effective and sustained spill containment and recovery operations.SECTION 3: Geological & Geophysical Information

A. Geological description

Omitted from PI copies.

B. Structure contour maps.

Omitted from PI copies.

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

Omitted from PI copies.

D. Geological Structure Cross-section(s)

Omitted from PI copies.

E. Shallow Hazards Report

– Geologic & Stratigraphic Assessment of Walker Ridge Blocks 95 & 139, prepared by GEMS for Shell Offshore Inc, dated February 19, 2009, project No. 1008-1564.

F. Shallow Hazards Assessment

Proposed Wellsite A (I in the Report) Shell, Block 95 (OCS-G-31943) Walker Ridge Area

Gulf of Mexico

The Proposed Wellsite A location in Walker Ridge area , Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

The seafloor at Proposed Wellsite A, Walker Ridge Bl ock 95 (OCS-G-31943), appears suitable for exploration drilling operations. The well bore will intersect a fault plane at approximately 200 ft bml. Soil conditions are likely to be very similar to those encountered in the nearby WR 52-1 well a few miles north of the proposed

location.

The Proposed Wellsite B location in Walker Ridge ar ea, Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

The Proposed Wellsite C location in Walker Ridge area , Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

The Proposed Wellsite D location in Walker Ridge area , Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).The Proposed Wellsite E location in Walker Ridge area , Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. . The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

Report prepared by GEOSCIENCE EARTH & MARINE SERVICES, INC.®

Thomas W. Neurauter Michael J. Kaluza Ph. D. Senior Marine Geologist President/Marine Geologist

G. High-Resolution Seismic Lines

Omitted from PI copies.

See attached ESR.

H & I Stratigraphic Column with Time vs depth table

Omitted from PI copies.SECTION 4: Hydrogen Sulfide

A. Concentration

0 ppm.

B. Classification

Based on CFR 250.490 (c), SOI requests that the Regi onal Supervisor, Field Operations, determine the zones in the proposed drilling operations in this plan to be classified as an area where the absence of H 2 S
has been confirmed.

C. H 2 S Contingency Plan In accordance with 30 CFR 250.490(f) a Continge ncy Plan is not required for this Lease.

D. Modeling Report

We do not anticipate to encounter or handle H 2 S at concentrations greater than 500 parts per million (ppm) and therefore have not included modeling for H 2 S.SECTION 5: Minerals Resource Conservation

Information regarding Mineral Resource Conservation is not included in this EP as such information is only necessary in the case of DOCDs.SECTION 6: Biological, Physical and Socioeconomic Information

A. Chemosynthetic Communities Report

The wells proposed in this Plan were previously reviewed in Plan N-9410 for Chemosynthetic Community clearance and biological, physical and socioeconomic re view using a semi-submersible with anchor radius. That Plan was approved without mitigations from the BO EMRE. This revised plan is not utilizing anchors and

should suffice to NTL 2010-G39 and G40.

Site Specific Assessments And Chemosynthetic Communities Clearance

Proposed Wellsite A (I in the Report) Shell, Block 95 (OCS-G-31943) Walker Ridge Area

Gulf of Mexico

The Proposed Wellsite A location in Walker Ridge area , Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

Introduction

Shell Offshore Inc., (Shell) contracted Geoscience Earth & Marine Services, Inc®., (GEMS) to prepare a geohazard analysis of Blocks 95 and 139 of the Wa lker Ridge (WR) Area, Gulf of Mexico. The geohazard report, submitted to Shell in February 2009 (GEMS, 2009) , discusses the seafloor an d subsurface conditions within these and surrounding blocks based on 3-D geop hysical data. Shell has desi gnated several possible drilling locations within the study area. This Site Cl earance Letter addresses the specific conditions at Proposed Wellsite WR 95-A (OCS-G-31943). The data se t, maps, and interpretations used for the geohazard report were reviewed for this assessment of Proposed Wellsite A. The figures included with this letter were

extracted from the 3-D data volume used for th e geohazard assessment (G EMS, 2009). The Proposed

Wellsite WR 95-A surface location is located in the no rtheastern quadrant of Block 95, Walker Ridge area, Gulf of Mexico. Shell provided the following coordinates:

Proposed Wellsite WR 95-A is Location I in the Report
Spheroid & Datum: Clarke 1866, NAD27 Projection:

UTM Zone 15 North Line Reference Block Calls

X: 2,101,095 ft Latitude:

26.863229287o N Inline 0420 7,122 ft FNL

Y: 9,750,318 ft Longitude: -

91.586560189o W Crossline 3098 5,625 ft FEL

Attachments The figures accompanying this letter we re extracted from the 3-D data volu me. The figures (listed below) are centered on the proposed well location. Figure I-1: Tophole Prognosis Chart, Proposed Wellsite A, Walker Ridge Block 95 Figure I-2: Inline 30420 and Crossline 3098 Showing Conditions Beneath Proposed Wellsite A, Walker Ridge Block 95 Project No. 1008-1564 Proposed Well WR 95-A Figure I-3: Power Spectrum Chart Based on 3-D Data Volume within 500-ft Radius of Proposed Wellsite A, Walker Ridge Block 95.

Water Depth and Seafloor Conditions The water depth at the proposed location is -5,848 ft (Figure I-1). The seafloor slopes to the west at a gradient of 1.034° (1.8%). WR 95-A is situated above a shallow salt sheet. The overburden above the top of salt is only 579 ft thick (Figures I-1 and I-2). The seaf loor topography in the area of WR 95-A mimics therough, faulted and folded salt surface. The location lies between a series of seafloor faults. The seafloor faults are approximately 175 ft to the southwest and 350 ft to the east-northeast of the proposed location.

Chemosynthetic Communities There is no evidence of hydrocarbon seepage within 1,500 ft of the proposed location. Therefore, the potential for high-density chemosynthetic communities with in 1,500 ft of the proposed location is negligible. The Amplitude-Enhanced Surface Rendering (Map 4; GEMS, 2009) shows normal or ambient amplitudes along the seabed near the proposed wellsite. The Enhanced Surface Rendering and Amplitude-Enhanced Surface Rendering (GEMS, 2009) show few indications of seepage-related features within the 16-block area examined for this evaluation. Anomalous seabed amp litudes occur in the northwest quadrant of WR 50, approximately 6.2 miles from the proposed location. The high-amplitude response is most likely caused by variable sediment properties within mass-transport deposits rather than gaseous sediments. These anomalous seabed amplitude returns are no t likely to influence anchor locations.

Man-Made Features An exploration well occurs approximately 4.1 miles nort h-northeast of the proposed location. The well is in the northwest corner of WR 52. Anadarko spudded the well in June 2008. No other infrastructure, shipwrecks, or other man-made debris are reported in the vicinity.

Stratigraphy
Inline 30420 and Crossline 3098 are the closest lines to the proposed WR 95-A location (Figure I-2). The Tophole Prognosis Chart (Figure I-1) shows the inline annotated with calculated depths to the various horizons and predicted lithology of the sequences, along with their potential for shallow water flow and shallow gas. The top of salt is estimated to be approx imately 579 ft below the mudline (bml) at this location. The relatively thin overburden is divided into two unit s or sequences. The sequences represent variations in depositional environments and possible changes in soil st rength and composition. The surficial unit, Unit 1 (Seafloor to Horizon A), to approxim ately 164 ft bml, will consist of mu d-rich hemipelagic and thin masstransport deposits. The soils at the seabed are likely to be soft high water content silty clays. The shear strength of the sediments will gradually increase with depth corresponding to a decrease in water content. Stiff, overconsolidated sediments have been encountered in some areas along the lower continental slope. These areas generally have experienced erosion from st rong bottom currents. No evidence of furrows or

other erosional seabed features are identified around the proposed wellsite. Ov erconsolidated sediments within Unit 1 may occur along the steep walls of the basins west, northwest, and south of the proposed

location.

Horizon A is a continuous prominent reflecting hori zon mapped throughout the study area. Horizon A marks the transition between the weakly stratified surficial unit (Unit 1) with a sequence of closely-spaced continuous reflection sequence of Unit 2 (Figure I- 2). Unit 2 possibly represents mud-rich turbidites interlayered with thin mass-transport deposits. Beneat h WR 95-A, Unit 2 is approximately 415ft thick (Figure I-1). The reflections within Unit 2 vary from parallel and continuous to discontinuous. The discontinuities within the section are caused by faulting and foldin g of the unit above the shallow salt sheet and not a change in depositional environment. The sediments within Unit 2 are likely alternating layers of clay and silt. Occasional thin sand seams are possi ble but no significant sand layers are likely. An increase in sediment shear strength will likely occur across the Horizon A interf ace (i.e., ~164 ft bml). The amount of increase will depend on the age and amount of sediment erosion in this section. Highly overco nsolidated sediments could influence the jetting of the surface conductor. Howe ver, no problems were reported when jetting the

conductor for the WR 52-1 well a few miles to the north. The top of salt at WR 95-A is at -6,427 ft subsea (579 ft bml). The salt surface dips to the east at ~2.5°.

Faults
Several seafloor faults occur in the area around WR 95-A (Maps 2a, 3, and 5; GEMS, 2009). The location is between the surface expression of two of these faults (Figures I-1 and I-2). These seafloor faults lie approximately 175 ft to the southwes t and 350 ft to the east-northeast of the proposed location. The well bore is predicted to intersect the fault plane for the western fault at approximately 200 ft below the mudline. Movement along the fault is likely analogous to soil creep.Shallow Water Flow Shallow water flow has not been reported in the Wa lker Ridge area (MMS, 2007). The sedimentary section above the salt surface is only 579 ft thick and there are no indications of sand-prone sequences. The potential for overpressure d sands is negligible.

Shallow Gas The well path will not penetrate any high-amplitude events between the seafloor and top of salt (Figure I-1). However, a high-amplitude event occurs approximately 550 ft to the east of the location (Figure I-1). The horizon that correlates with event is 490 ft beneath the mudline. The amplitude event possibly represents a thin sand layer with some biogenic gas. At the proposed location the sand should be very thin and based on the reduced amplitude, does not have the concentration of biogenic gas. Therefore the potential of shallow gas at this level (~490 ft bml) is considered low.

Power Spectrum
In accordance with NTL 2008-G04 and NTL 2008-G05 (MMS 2008a,b), we have extracted the power spectrum diagram (Figure I-3) from the 3-D seismic data cube. The extraction was generated within a 500-ft

radius of the intersection of the inlines and crosslines at the proposed wellsite. We converted the amplitude vs. frequency spectrum, generated by the SMT software , to power vs. frequency by squaring the amplitude values as described by J. A. Coffeen, 1978.

Closing The seafloor at Proposed Wellsite A, Walker Ridge Bl ock 95 (OCS-G-31943), appears suitable for exploration drilling operations. The well bore will intersect a fault plane at approximately 200 ft bml. Soil conditions are likely to be very similar to those encountered in the nearby WR 52-1 well a few miles north of the proposed

location.

Proposed Wellsite B (A in Report) Shell, Block 95 (OCS-G-31943) Walker Ridge Area

Gulf of Mexico

The Proposed Wellsite B location in Walker Ridge ar ea, Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

Introduction Shell Offshore Inc., (Shell) contracted Geoscience Earth & Marine Services, Inc®., (GEMS) to prepare a geohazard analysis of Blocks 95 and 139 of the Wa lker Ridge (WR) Area, Gulf of Mexico. The geohazard report discusses the seafloor and subsurface conditions within these and surrounding blocks based on 3-D geophysical data. Shell has designated several possibl e drilling locations within the study area. This Site Clearance Letter addresses the spec ific conditions at Proposed We llsite WR 95-B (OCS-G-31943). This proposed location is plotted on the maps referenced in the main text of this report. The figures included with

this letter are taken from the 3-D data volume used for the geohazard assessment of the study area. The Proposed Wellsite WR 95-B surface location is located in the northeastern quadrant of Block 95, Walker Ridge area, Gulf of Mexico. Shell provided the following coordinates:

Proposed Wellsite WR 95-B is Location A in the Report
Spheroid & Datum: Clarke 1866, NAD27 Projection:

UTM Zone 15 North Line Reference Block Calls

X: 2,102,641 ft Latitude:

26.862056527o N Inline 30390 7,531 ft FNL

Y: 9,749,909 ft Longitude: -

91.581832000o W Crossline 3136 4,079 ft FELAttachments The figures accompanying this letter we re extracted from the 3-D data volu me. The figures (listed below) are centered on the proposed well location. Figure A-1: Tophole Prognosis Chart, Proposed Wellsite B, Walker Ridge Block 95 Figure A-2: Inline 30390 and Crossline 3136 Showing Cond itions Beneath Proposed Wellsite B, Walker Ridge Block 95 Figure A-3: Power Spectrum Chart Based on 3-D Data Volume Within 500-ft Radius of Proposed Wellsite B, Walker Ridge Block 95.

Water Depth and Seafloor Conditions The water depth at the proposed location is -5,833 ft (F igure A-1). The seafloor slop es to the southwest at a gradient of 2.4° (4.2%). WR 95-B is situated above a shallow salt sheet. The overburden above the top of salt is only 651 ft thick (Figures A-1 and A-2). The sea floor topography mimics the rough, faulted and folded

salt surface. Several faults affect the seafloor ar ound the proposed location. The closest offset is approximately 150 ft to the east of WR 95-A.

Chemosynthetic Communities There is no evidence of hydrocarbon seepage within 1,500 ft of the proposed location. Therefore, the potential for high-density chemosynthetic communities with in 1,500 ft of the proposed location is negligible. The Amplitude-Enhanced Surface Rendering (Map 4) sh ows normal or ambient amplitudes along the seabed near the proposed wellsite. The Enhanced Surface Rendering and Amplitude-Enhanced Surface Rendering show few indications of seepage-related features with in the 16-block area examined for this evaluation. Anomalous seabed amplitudes occur in the northwest quadrant of WR 50, approximately 6 miles from the proposed location. The high-amplitude response is most likely caused by variable sediment properties within mass-transport deposi ts rather than gaseous sediments. In an y case, these anomalous seabed amplitude returns are six miles from the proposed location and not likely to influence anchor locations.

Man-Made Features An exploration well occurs approximately 4 miles north-no rtheast of the proposed location. The well is in the northwest corner of WR 52. Anadarko spudded the we ll in June, 2008. No shipwrecks or other man-made debris are reported in the vicinity.

Stratigraphy
Inline 30390 and Crossline 3136 are the closest lines to the proposed WR 95-B location (Figure A-2). The Tophole Prognosis Chart (Figure A-1) shows the inline annotated with calculated depths to the various horizons and predicted lithology of the sequences, along with their potential for shallow water flow and shallow gas. The top of salt is estimated to be approx imately 651 ft below the mudline (bml) at this location. The relatively thin overburden is divided into two unit s or sequences. The sequences represent variations in depositional environments and possible changes in soil st rength and composition. The surficial unit, Unit 1 (Seafloor to Horizon A), to approxim ately 166 ft bml, will consist of mu d-rich hemipelagic and thin masstransport deposits. The soils at the seabed are likely to be soft high water content silty clays. The shear strength of the sediments will gradually increase with depth corresponding to a decrease in water content. Stiff, overconsolidated sediments have been encountered in some areas along the lower continental slope. These areas generally have experienced er osion from strong bottom currents.

No evidence of furrows or other erosional seabed fe atures are identified around the proposed wellsite. Overconsolidated sediments may occur along the steep walls of the basin west of the proposed location.

Horizon A is a continuous prominent reflecting hori zon mapped throughout the study area. Horizon A marks the transition between the weakly stratified surficial unit (Unit 1) with a sequence of closely-spaced continuous reflection sequence of Unit 2 (Figure A- 2). Unit 2 possibly represents mud-rich turbidites interlayered with thin mass-transport deposits. Beneat h WR 95-B, Unit 2 is approximately 485 ft thick (Figure A-1). The reflections within Unit 2 vary from parallel and continuous to discontinuous. The discontinuities within the section are caused by faulting and foldin g of the unit above the shallow salt sheet and not a change in depositional environment. The sediments within Unit 2 are likely alternating layers of clay and silt. Occasional thin sand seams are possi ble but no significant sand layers are likely. An increase in sediment shear strength will likely occur across the Horizon A interf ace (i.e., ~166 ft bml). The amount of increase will depend on the age of sediment in this section. The amount of increase will depend on the age and amount of sediment erosion in this section. Highly overconsolidat ed sediments could influence the jetting of the surface conductor. However, no problems were reported when jetting the conductor for the WR 52-1 well a few miles to the north. The top of salt at WR 95-B is at -6,484 ft subsea (651ft bml). The salt surface dips to the west

at 5.2°.Faults
Several seafloor faults occur in the area around WR 95- B (Maps 2a and 3). The closest faults are 150 ft to the east. The fault is downthrown west (Figures A-1 and A- 2). The well bore at WR 95-B will intersect the fault plane at approximate position of Horizon A which is 166 ft bml.

Shallow Water Flow Shallow water flow has not been reported in the Wa lker Ridge area (MMS, 2007). The sedimentary section above the salt surface is only 651 ft thick and there are no indications of sand-prone sequences. The potential for overpressure d sands is negligible.

Shallow Gas The well path will not penetrate any high-amplitude events between the seafloor and top of salt (Figure A-1). The potential for shallow gas accumulations beneath WR 95-B is negligible.

Power Spectrum
In accordance with NTL 2008-G04 and NTL 2008-G05 (MMS 2008a,b), we have extracted the power spectrum diagram (Figure A-3) from the 3-D seismic da ta cube. The extraction wa s generated within a 500-ft

radius of the intersection of the inlines and crosslines at the proposed wellsite. We converted the amplitude vs. frequency spectrum, generated by the SMT software , to power vs. frequency by squaring the amplitude values as described by J. A. Coffeen, 1978.

Closing The seafloor at Proposed Wellsite B, Walker Ridge Bl ock 95 (OCS-G-31943), appears suitable for exploration drilling operations. The well bore will intersect a fault plane at approximately 166 ft bml. Soil conditions should be very similar to those encountered in the WR 52-1 well a few miles north of the proposed location.

Proposed Wellsite C (E in the Report) Shell, Block 95 (OCS-G-31943) Walker Ridge Area

Gulf of Mexico

The Proposed Wellsite C location in Walker Ridge area , Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

Introduction

Shell Offshore Inc., (Shell) contracted Geoscience Earth & Marine Services, Inc®., (GEMS) to prepare a geohazard analysis of Blocks 95 and 139 of the Wa lker Ridge (WR) Area, Gulf of Mexico. The geohazard report, submitted to Shell in February, 2009 (GEMS, 2009) , discusses the seafloor an d subsurface conditions within these and surrounding blocks based on 3-D geop hysical data. Shell has desi gnated several possible drilling locations within the study area. This Site Cl earance Letter addresses the specific conditions at Proposed Wellsite WR 95-C (OCS-G-31943). The data set, maps, and interpretations used for the geohazard report were reviewed for this assessment of Proposed Wellsite C. The figures included with this letter were

extracted from the 3-D data volume used for th e geohazard assessment (G EMS, 2009). The Proposed

Wellsite WR 95-C surface location is located in the nort heastern corner of Block 95, Walker Ridge area, Gulf of Mexico. Shell provided th e following coordinates:

Proposed Wellsite WR 95-C is Location E in Report
Spheroid & Datum: Clarke 1866, NAD27 Projection:

UTM Zone 15 North Line Reference Block Calls

X: 2,105,685 ft Latitude:

26.872455722o N Inline 30680 3,717 ft FNL

Y: 9,753,723 ft Longitude: -

91.572363151o W Crossline 3210 1,035 ft FEL

AttachmentsThe figures accompanying this letter we re extracted from the 3-D data volu me. The figures (listed below) are centered on the proposed well location. Figure E-1: Tophole Prognosis Chart, Proposed Wellsite C, Walker Ridge Block 95 Figure E-2: Inline 30680 and Crossline 3210 Showing Conditions Beneath Proposed Wellsite C, Walker Ridge Block 95 Figure E-3: Power Spectrum Chart Based on 3-D Data Volume Within 500-ft Radius of Proposed Wellsite C, Walker Ridge Block 95.

Water Depth and Seafloor Conditions The water depth at the proposed location is -5,860 ft (Figure E-1). The seafloor slopes to the southeast at a gradient of 0.83° (1.4%). WR 95-C is situated above a shallow salt sheet. The overburden above the top of salt is only 556 ft thick (Figures E-1 and E-2). The sea floor topography in the area of WR 95-C mimics the rough, faulted and folded salt surface.

Chemosynthetic Communities There is no evidence of hydrocarbon seepage within 1,500 ft of the proposed location. Therefore, the potential for high-density chemosynthetic communities with in 1,500 ft of the proposed location is negligible. The Amplitude-Enhanced Surface Rendering (Map 4; GEMS, 2009) shows normal or ambient amplitudes along the seabed near the proposed wellsite. The Enhanced Surface Rendering and Amplitude-Enhanced Surface Rendering (GEMS, 2009) show few indications of seepage-related features within the 16-block area examined for this evaluation. Anomalous seabed amp litudes occur in the northwest quadrant of WR 50, approximately 5.5 miles from the proposed location. The high-amplitude response is most likely caused by variable sediment properties within mass-transport deposits rather than gaseous sediments. These anomalous seabed amplitude returns are no t likely to influence anchor locations.

Man-Made Features An exploration well occurs approximately 3.3 miles nort h-northeast of the proposed location. The well is in the northwest corner of WR 52. Anadarko spudded the well in June 2008. No other infrastructure, shipwrecks, or other man-made debris are reported in the vicinity.

Stratigraphy
Inline 30680 and Crossline 3210 are the closest lines to the proposed WR 95-E location (Figure E-2). The Tophole Prognosis Chart (Figure E-1) shows the inline annotated with calculated depths to the various horizons and predicted lithology of the sequences, along with their potential for shallow water flow and shallow gas. The top of salt is estimated to be approx imately 556 ft below the mudline (bml) at this location. The relatively thin overburden is divided into two unit s or sequences. The sequences represent variations in depositional environments and possible changes in soil st rength and composition. The surficial unit, Unit 1 (Seafloor to Horizon A), to approxim ately 166 ft bml, will consist of mu d-rich hemipelagic and thin masstransport deposits. The soils at the seabed are likely to be soft high water content silty clays. The shear strength of the sediments will gradually increase with depth corresponding to a decrease in water content. Stiff, overconsolidated sediments have been encountered in some areas along the lower continental slope. These areas generally have experienced erosion from st rong bottom currents. No evidence of furrows or

other erosional seabed features are identified around the proposed wellsite. Ov erconsolidated sediments within Unit 1 may occur along the steep walls of the basins west, northwest, and south of the proposed

location.

Horizon A is a continuous prominent reflecting hori zon mapped throughout the study area. Horizon A marks the transition between the weakly stratified surficial unit (Unit 1) with a sequence of closely-spaced continuous reflection sequence of Unit 2 (Figure E- 2). Unit 2possibly represents mud-rich turbidites interlayered with thin mass-transport deposits. Beneat h WR 95-C, Unit 2 is approximately 390 ft thick (Figure E-1). The reflections within Unit 2 vary from parallel and continuous to discontinuous. The discontinuities within the section are caused by faulting and foldin g of the unit above the shallow salt sheet and not a change in depositional environment. The sediments within Unit 2 are likely alternating layers of clay and silt. Occasional thin sand seams are possi ble but no significant sand layers are likely. An increase in sediment shear strength will likely occur across the Horizon A interf ace (i.e., ~166 ft bml). The amount of increase will depend on the age and amount of sediment erosion in this section. Highly overco nsolidated sediments could influence the jetting of the surface conductor. Howe ver, no problems were reported when jetting the

conductor for the WR 52-1 well a few miles to the north. The top of salt at WR 95-E is at -6,416 ft subsea (556 ft bml). The salt surface di ps to the north at ~3.1°.Faults
Several seafloor faults occur in the area around WR 95-C (Maps 2a, 3, and 5; GEMS, 2009). The seafloor is irregular in the area of the proposed wellsite, however, no well-defined seafloor offsets occur within ~1,000 ft of the location (Figures E-1 and E-2). The wellbore will no intersect any fault planes at depth.

Shallow Water Flow Shallow water flow has not been reported in the Wa lker Ridge area (MMS, 2007). The sedimentary section above the salt surface is only 556 ft thick and there are no indications of sand-prone sequences. The potential for overpressure d sands is negligible.

Shallow Gas The well path will not penetrate any high-amplitude events between the seafloor and top of salt (Figure E-1). However, a slightly high-amplitude event occurs approxima tely 1,200 ft to the west of the location (Figure E1). The horizon that correlates with event is 322 ft beneath the mudline. The amplitude event possibly represents a thin sand layer with some biogenic gas. At the proposed location the sand should be very thin or non-existent. Based on the reduced amplitude, a concen tration of biogenic gas is unlikely. Therefore, the potential of shallow gas at this level (~ 332 ft bml) is considered negligible.

Power Spectrum
In accordance with NTL 2008-G04 and NTL 2008-G05 (MMS 2008a,b), we have extracted the power spectrum diagram (Figure E-3) from the 3-D seismic data cube. The extraction was generated within a 500-ft

radius of the intersection of the inlines and crosslines at the proposed wellsite. We converted the amplitude vs. frequency spectrum, generated by the SMT software , to power vs. frequency by squaring the amplitude values as described by J. A. Coffeen, 1978.

Closing The seafloor at Proposed Wellsite C, Walker Ridge Bl ock 95 (OCS-G-31943), appears suitable for exploration drilling operations. The well bore will not intersect any fa ult planes or shallow gas at depth. Soil conditions are likely to be very similar to those en countered in the nearby WR 52-1 well.

Proposed Wellsite D (D in Report) Shell, Block 95 (OCS-G-31943) Walker Ridge Area

Gulf of Mexico

The Proposed Wellsite D location in Walker Ridge area , Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

Introduction

Shell Offshore Inc., (Shell) contracted Geoscience Earth & Marine Services, Inc®., (GEMS) to prepare a geohazard analysis of Blocks 95 and 139 of the Wa lker Ridge (WR) Area, Gulf of Mexico. The geohazard report discusses the seafloor and subsurface conditions within these and surrounding blocks based on 3-D geophysical data. Shell has designated several possibl e drilling locations within the study area. This Site Clearance Letter addresses the specific conditions at Proposed Wellsite WR 95-D (OCS-G-31943). This proposed location is plotted on the maps referenced in the main text of this report. The figures included with

this letter are taken from the 3-D data volume used for the geohazard assessment of the study area. The Proposed Wellsite WR 95-D surface location is located in the northeastern quadrant of Block 95, Walker Ridge area, Gulf of Mexico. Shell provided the following coordinates:Proposed Wellsite WR 95-D
Spheroid & Datum: Clarke 1866, NAD27 Projection:

UTM Zone 15 North Line Reference Block Calls

X: 2,101,293 ft Latitude:

26.861344111o N Inline 30370 7,805 ft FNL

Y: 9,749,635 ft Longitude: -

91.585976207o W Crossline 3103 5,427 ft FEL

Attachments The figures accompanying this letter were extracted fr om the 3-D data volumes. The figures (listed below) are centered on the proposed well location. Figure D-1 : Tophole Prognosis Chart, Proposed Wellsite D, Walker Ridge Block 95 Figure D-2: Inline 30370 and Crossline 3103 Showing Conditions Beneath Proposed Wellsite D, Walker Ridge Block 95 Figure D-3: Power Spectrum Chart Based on 3-D Data Volume Within 500-ft Radius of Proposed Wellsite D, Walker Ridge Block 95.

Water Depth and Seafloor Conditions The water depth at the proposed location is -5,949 ft (Figure D-1). The seafloor slopes to the east at a gradient of 3.0° (5.2%).

WR 95-D is situated above a shallow salt sheet. The overburden above the top of salt is only 591 ft thick (Figures D-1 and D-2). The seafloor topography mimics the rough, faulted and folded salt surface. Several faults affect the seafloor around the proposed location . The closest offset is approximately 215 ft to the east

of WR 95-D.

Chemosynthetic Communities There is no evidence of hydrocarbon seepage within 1,500 ft of the proposed location. Therefore, the potential for high-density chemosynthetic communities with in 1,500 ft of the proposed location is negligible. The Amplitude-Enhanced Surface Rendering (Map 4) sh ows normal or ambient amplitudes along the seabed near the proposed wellsite. The Enhanced Surface Rendering and Amplitude-Enha nced Surface Rendering show few indications of seepage-related features within the 16-block area examined for this evaluation. Anomalous seabed amplitudes occur in the northwest quadrant of WR 50, approximately 6 miles from the proposed location. The high-amplitude response is most likely caused by variable sediment properties within mass-transport deposits rather than gaseous sediments. In any case, these an omalous seabed amplitude re turns are six miles from the proposed location and not likely to influence anchor locations.

Man-Made Features An exploration well occurs approximately 4.3 miles nort h-northeast of the proposed location. The well is in

the northwest corner of WR 52. Anad arko spudded the well in June, 2008. No shipwrecks or other man-made debris are reported in the vicinity.

Stratigraphy
Inline 30370 and Crossline 3103 are the closest lines to th e proposed WR 95-D location (Figure D-2). The Tophole Prognosis Chart (Figure D-1) shows the inline annotated with calculated depths to the various horizons and predicted lithology of the sequences, along with their potential for shallow water flow and shallow gas.

The top of salt is estimated to be approximately 591 ft below the mudline (bml) at this location. The relatively thin overburden is divided into two units or sequence s. The sequences represent variations in depositional environments and possible changes in soil strength and composition. The surficial unit, Unit 1 (Seafloor to Horizon A), to approximately 158 ft bml, will consist of mud-rich hemipelagic and thin mass-transport deposits. The soils at the seabed are likely to be soft high water content silty clays. The shear strength of the sediments w ill gradually increase with depth corresponding to a decrease in water content. Stiff, ov erconsolidated sediments have been encountered in some areas along the lower continental slope. These areas generally have ex perienced erosion from stro ng bottom currents. No

evidence of furrows or other erosional seabed feat ures are identified around the proposed wellsite. Overconsolidated sediments may occur along the steep walls of the basins west and north of the proposed

location.Horizon A is a continuous prominent reflecting hori zon mapped throughout the study area. Horizon A marks the transition between the weakly stratified surficial unit (Unit 1) with a sequence of closely-spaced continuous reflection sequence of Unit 2 (Figure D- 2). Unit 2 possibly represents mud-rich turbidites interlayered with thin mass-transport deposits. Beneat h WR 95-D, Unit 2 is approximately 433 ft thick (Figure D-1). The reflections within Unit 2 vary from parallel and continuous to discontinuous. The discontinuities within the section are caused by faulting and foldin g of the unit above the shallow salt sheet and not a change in depositional environment. The sediments within Unit 2 are likely alternating layers of clay and silt. Occasional thin sand seams are possi ble but no significant sand layers are likely. An increase in sediment shear strength will likely occur across the Horizon A interf ace (i.e., ~158 ft bml). The amount of increase will depend on the age of sediment in this section. The amount of increase will depend on the age and amount of sediment erosion in this section. Highly overconsolidat ed sediments could influence the jetting of the surface conductor. However, no problems were reported when jetting the conductor for the WR 52-1 well a few miles to the north. The top of salt at WR 95-D is at -6,540 ft subsea (591 ft bml). The salt surface dips to the east

at 3.3°

Faults
Several seafloor faults occur in the area around WR 95-D (Maps 2a and 3). The closest fault is 215 ft to the east and is downthrown away from the location. The ot her seafloor faults in the area are over 500 ft away from the WR 95-D location. Reflections at depth, in pl aces, are discontinuous but no well-defined fault planes are defined beneath the proposed location.

Shallow Water Flow Shallow water flow has not been reported in the Walk er Ridge area (MMS, 2007c). The sedimentary section above the salt surface is 591 ft thick and there are no indications of sand-prone sequences. The potential for overpressured sands is negligible.

Shallow Gas The well path will not penetrate any high-amplitude events between the seafloor and top of salt (Figure D-1). The potential for shallow gas accumulations beneath WR 95-D is negligible.

Power Spectrum
In accordance with NTL 2008-G04 and NTL 2008-G05 (MMS 2008a,b), we have extracted the power spectrum diagram (Figure D-3) from the 3-D seismic da ta cube. The extraction was generated within a 500-ft

radius of the intersection of the inlines and crosslines at the proposed wellsite. We converted the amplitude vs. frequency spectrum, generated by the SMT software , to power vs. frequency by squaring the amplitude values as described by J. A. Coffeen, 1978.

Closing The seafloor at Proposed Wellsite D, Walker Ridge Bl ock 95 (OCS-G-31943), appears suitable for exploration drilling operations. No major hazards or constraints are defined by the 3-D da ta at the proposed location. Soil conditions should be very similar to those encountere d in the WR 52-1 well a few miles north of the proposed

location.

Proposed Wellsite E (B in Report) Shell, Block 95 (OCS-G-31943) Walker Ridge Area

Gulf of Mexico

The Proposed Wellsite E location in Walker Ridge area , Block 95 appears favorable for exploration drilling operations relevant to the shallow geologic and stra tigraphic conditions. . The geohazard report (No. 1008- 1564) and this letter comply with the Minerals Manage ment Service (MMS) Notice -to-Lessees (NTL’s) 2000- G20, 2005-G07, and 2008-G05 (MMS, 2000, 2005, and 2008a, respectively).

Introduction

Shell Offshore Inc., (Shell) contracted Geoscience Earth & Marine Services, Inc®., (GEMS) to prepare a geohazard analysis of Blocks 95 and 139 of the Wa lker Ridge (WR) Area, Gulf of Mexico. The geohazard report discusses the seafloor and subsurface conditions within these and surrounding blocks based on 3-D geophysical data. Shell has designated several possibl e drilling locations within the study area. This Site Clearance Letter addresses the spec ific conditions at Proposed Wellsite WR 95-E (OCS-G-31943). This proposed location is plotted on the maps referenced in the main text of this report. The figures included with

this letter are taken from the 3-D data volume used for the geohazard assessment of the study area. TheProposed Wellsite WR 95-E surface location is located in the southeastern quadrant of Block 95, Walker Ridge area, Gulf of Mexico. Shell provided the following coordinates:

Proposed Wellsite WR 95-E is B in the Report
Spheroid & Datum: Clarke 1866, NAD27 Projection:

UTM Zone 15 North Line Reference Block Calls

X: 2,102,576 ft Latitude:26.8600033

49o N Inline 30335 7,562 ft FSL

Y: 9,749,162 ft Longitude: -

91.582057006o W Crossline 3134 4,144 ft FEL

Attachments The figures accompanying this letter were extr acted from the 3-D data volume. The figures (listed below) are centered on the proposed well location. Figure B-1: Tophole Prognosis Chart, Proposed Wellsite E, Walker Ridge Block 95 Figure B-2: Inline 30335 and Crossline 3134 Showing Conditions Beneath Proposed Wellsite E, Walker Ridge

Block 95 Figure B-3: Power Spectrum Chart Based on 3-D Data Volume Within 500-ft Radius of Proposed Wellsite E, Walker Ridge Block 95.

Water Depth and Seafloor Conditions The water depth at the proposed location is -5,843 ft (F igure B-1). The seafloor slopes to the northeast at a gradient of 1.2° (2.1%). WR 95-E is situated above a shallow salt sheet. The ov erburden above the top of salt is only 628 ft thick (Figures B-1 and B-2). The sea floor topography mimics the rough, faulted and folded

salt surface. The seafloor in the area of WR 95-E is irregular and hummocky. The location lies between a series of seafloor faults. The seafloor offsets are appr oximately 300 ft to the east and west of the proposed

location.

Chemosynthetic Communities There is no evidence of hydrocarbon seepage within 1,500 ft of the proposed location. Therefore, the potential for high-density chemosynthetic communities with in 1,500 ft of the proposed location is negligible. The Amplitude-Enhanced Surface Rendering (Map 4) sh ows normal or ambient amplitudes along the seabed near the proposed wellsite. The Enhanced Surface Rendering and Amplitude-Enhanced Surface Rendering show few indications of seepage-related features with in the 16-block area examined for this evaluation. Anomalous seabed amplitudes occur in the northwest quadrant of WR 50, approximately 6.3 miles from the proposed location. The high-amplitude response is most likely caused by variable sediment properties within mass-transport deposi ts rather than gaseous sediments. In an y case, these anomalous seabed amplitude returns are six miles from the proposed location and not likely to influence anchor locations.

Man-Made Features An exploration well occurs approximately 4.3 miles nort h-northeast of the proposed location. The well is in the northwest corner of WR 52. Anadarko spudded the well in June 2008. No shipwrecks or other man-made debris are reported in the vicinity.

Stratigraphy
Inline 30335 and Crossline 3134 are the closest lines to th e proposed WR 95-E location (Figure B-2). The Tophole Prognosis Chart (Figure B-1) shows the inline annotated with calculated depths to the various horizons and predicted lithology of the sequences, along with their potential for shallow water flow and shallow gas. The top of salt is estimated to be approx imately 628 ft below the mudline (bml) at this location. The relatively thin overburden is divided into two unit s or sequences. The sequences represent variations in depositional environments and possible chan ges in soil strength and composition.

The surficial unit, Unit 1 (Seafloor to Horizon A), to approximately 171 ft bml, will consist of mud-rich hemipelagic and thin mass-transport deposits. The soils at the seabed are likely to be soft high water content silty clays. The shear strength of the sediments w ill gradually increase with depth corresponding to a decrease in water content. Stiff, ov erconsolidated sediments have been encountered in some areas along the lower continental slope. These areas generally have ex perienced erosion from stro ng bottom currents. No

evidence of furrows or other erosional seabed feat ures are identified around the proposed wellsite. Overconsolidated sediments may occur along the steep walls of the basins west and north of the proposed

location.Horizon A is a continuous prominent reflecting hori zon mapped throughout the study area. Horizon A marks the transition between the weakly stratified surficial unit (Unit 1) with a sequence of closely-spaced continuous reflection sequence of Unit 2 (Figure B- 2). Unit 2 possibly represents mud-rich turbidites interlayered with thin mass-transport deposits. Beneat h WR 95-E, Unit 2 is approxi mately 457 ft thick (Figure B-1). The reflections within Unit 2 vary from parallel and continuous to discontinuous. The discontinuities within the section are caused by faulting and foldin g of the unit above the shallow salt sheet and not a change in depositional environment. The sediments within Unit 2 are likely alternating layers of clay and silt. Occasional thin sand seams are possi ble but no significant sand layers are likely. An increase in sediment shear strength will likely occur across the Horizon A interf ace (i.e., ~171 ft bml). The amount of increase will depend on the age and amount of sediment erosion in this section. Highly overco nsolidated sediments could influence the jetting of the surface conductor. Howe ver, no problems were reported when jetting the

conductor for the WR 52-1 well a few miles to the north. The top of salt at WR 95-E is at -6,471 ft subsea (628 ft bml). The salt surface dips to the north at 3.7°.

Faults
Several seafloor faults occur in the area around WR 95-E (Maps 2a, 3, and 5). Th e location is between the surface expressions of two of these faults (Figures B- 1 and B-2). The well is roughly equidistance from the seafloor offsets (~300 ft). The well bore is predicted to intersect the fault plane for the western fault at approximately 291 ft below the mudline.

Shallow Water Flow Shallow water flow has not been reported in the Wa lker Ridge area (MMS, 2007). The sedimentary section above the salt surface is only 628 ft thick and there are no indications of sand-prone sequences. The potential for overpressure d sands is negligible.

Shallow Gas The well path will not penetrate any high-amplitude events between the seafloor and top of salt (Figure B-1). The potential for shallow gas accumulations beneath WR 95-E is negligible.

Power Spectrum
In accordance with NTL 2008-G04 and NTL 2008-G05 (MMS 2008a,b), we have extracted the power spectrum diagram (Figure B-3) from the 3-D seismic da ta cube. The extraction was generated within a 500-ft

radius of the intersection of the inlines and crosslines at the proposed wellsite. We converted the amplitude vs. frequency spectrum, generated by the SMT software , to power vs. frequency by squaring the amplitude values as described by J. A. Coffeen, 1978.

Closing The seafloor at Proposed Wellsite E, Walker Ridge Bl ock 95 (OCS-G-31943), appears suitable for exploration drilling operations. The well bore will inters ect a fault plane at approximately 291 ft.

Report prepared by GEOSCIENCE EA RTH & MARINE SERVICES, INC.®

Thomas W. Neurauter Michael J. Kaluza Ph. D. Senior Marine Geologist President/Marine Geologist

B – F

Pursuant to NTL No. 2008-G04 the proposed operations covered by this EP do not involve operations impacting the following: Topographic features map, Topographic features st atement (shunting), Live bottoms, (Pinnacle Trend) map, Live bottoms (low relief ) map, potentially sensitive biological features map.G. Remotely Operated Vehicle (ROV) Monitoring Plan

In accordance with the provisions of NTL No. 2008-G06, Remotely Operated Vehicle Surveys in Deepwater, Walker Ridge Block 95 is located in Grid 10. Grid 10 is an area that has adequate ROV survey coverage; therefore we are not proposing to run the pre and po st 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 coeruleoalbaI. Archaeological Report

WR 95 is not in an area of high potential for historic shipwrecks. At the time of this Revised EP filing, no archaeological data had been acquired. Prior to perf orming any bottom-disturbing activities such as casing setting at the proposed well surface locations, a surv ey will be conducted covering any impacted seafloor using digital global positioning system DGPS or an equ ivalent navigation system. The area may be surveyed by an autonomous underwater vehicle, a deep tow surv ey, or an ROV survey with a marine archaeologist on board. Shell will submit the archaeological report to the BOEMRE as soon as it becomes available. Alternatively, in the case of an ROV survey, Shell will post the statements to the BOEMRE site in compliance with the approved Revised EP Mitigation and submit the required End of Operations Report (EOR).

J. Air and Water Quality Information

Pursuant to NTL No. 2008-G04 the prop osed 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 prop osed operations covered by this EP do not require Shell to provide additional information relating to air and water qualit y information. For specific information relating to socioeconomic information please refer to the EIA, Attachment 18.SECTION 7: Waste and Discharge Information

A. Discharge to GOM or Downhole

Note: Please specify if the amount reported is a total or per well amount Walker Ridge 95

Type of Waste and Composition Composition Projected Amount Discharge rate Discharge Method Answer yes or no
Will drilling occur ? If yes, you should list muds and cuttings

EXAMPLE: Cuttings wetted with ynthetic based fluid C u tti ngs genera t e d w

hil e us i ng syn th e ti c based drilling fluid. X bbl/well X bbl/day discharge pipe No

Water-based drilling fluid barite, additives, mud 20,000 bbls / well 3,333 bbls / day Overboard and seafloor discharge prior to

marine riser installation No
Water-based drilling fluid barite, additives, mud 1,000 bbls / well 1,000 bbls / day discharge overboard No

Cuttings wetted with water-based fluid cuttings coated with water based drilling mud 984 bbls / well 164 bbls / day Sea bed during riserless dr illing No

Cuttings wetted with synthetic-based fluid Cuttings generated while using synthetic based drilling fluid. 7,347 bbls / well 40 bbls / day Overboard discharge line to 39.4’ below the

water level No

Synthetic based drilling fluid adhering to washed dr ill
cuttings Synthetic based drilling fluid adhering to washed drill cuttings 3,726 bbls / well 15 bbls / day Overboard discharge line to 39.4’ below the

water level No

Chemical product waste 50 bbls / well 2 bbls / day Treated to meet NPDES limits and
discharged overboard No

Brine brine N/A N/A N/A No

Will humans be there? If yes, expect conventional waste

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

Domestic waste (kitchen water, shower water) grey water 26,000 bbls/well 130 bbls / day Grinded to less than 25 mm mesh size and
discharge overboard No

Sanitary waste (toilet water) treated sanitary waste 6,000 bbls/well 30 bbls / day Treated in the MSD** prior to discharge to

meet NPDES limits No
Is there a deck? If yes, there will be Deck Drainage

Deck Drainage Wash and rainwater 3,900 bbls / well 20 bbls / day Drained overboard through deck scuppers No

Will you conduct well treatment, completion, or workover?

well treatment fluids NA NA NA NA No
well completion fluids NA NA NA NA No

workover fluids NA NA NA NA No
Miscellaneous discharges. If yes, only fill in those associated with your activity.

Desalinization unit discharge Rejected water from watermaker unit 74,100 bbls / well 380 bbls /day Discharged overboard 35 feet below

waterline No
Blowout prevent fluid Water based 400 bbls/well 50 bbls/day Disharge at seafloor No

Ballast water Uncontaminated seawater 390,000 bbls / well 2,000 bbls / day Discharged overboard Just above waterline No

Bilge water Bilge and drainage water w ill be treated to MARPOL standards (< 15ppm oil in water). 390,000 bbls / well 2,000 bbls / day Bilge and drainage water w ill be treated to MARPOL standards (< 15ppm oil in water). No

Excess cement at seafloor Cement slurry 246 bbls/well (assume planned 100% excess is discharged) 246 bbls / well Discharged at the seafloor during riserless
drilling No
Fire water Treated seawater 11,000 bbls / well 2,000 bbls / month Drained overboard through deck scuppers No

Cooling water Treated seawater 23,295,000 bbls / well 145,000 bbls / day Discharged overboard 40 feet below

waterline No
Will you produce hydrocarbons? If yes fill in for produced water.

Produced water NA NA NA NA NA
Will you be covered by an individual or general NPDES permit ? GENERAL PERMIT GMG290103

NOTE: If you will not have a type of waste, enter NA in the row. TABLE 7A: WASTES YOU WILL GENERATE, TREAT AND DOWNHOLE DISPOSE OR DISCHARGE TO

THE GOM

Projected

Downhole Disposal Projected generated waste Projected ocean dischargesB. Landfill, inject, incinerate or recycle table

C. Modeling Report

Shell did not model the trajectory for discharg es because it is not required in the GOM. Solid and Liquid Wastes transportation

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

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

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

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

Synthetic-based drilling fluid or mud used SBF and additives Drums on barges Newpark Environmental Services (Fourchon, La.) or US Liquids of Louisiana (Fourchon, La.) 2,500 bbls/well Recycled

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

Cuttings wetted with Synthetic-based fluid Drill cuttings from synthetic
based interval. storage tank on supply boat. Newpark Environmental Services (Fourchon, La.) or US Liquids of Louisiana (Fourchon, La.) 300 bbls / well disposed

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

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

Produced sand NA NA NA NA NA

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

Trash and debris - recyclables trash and debris storage bins on supply boat Omega Waste Management, W. Patterson, LA or ARC, New Iberia, LA 60 lbs/month recylce

Non-Hazardous trash and debris - nonrecyclables trash and debris storage bins on supply boat Republic/BFI landfill, Sorrento, LA or the parish landfill, Avondale, LA. 118 lbs/month landfill

Hazardous waste paints, solvents and unused chemicals drums on supply boat Safety Kleen, Denton, TX 60 lbs/month recylce

Used oil & glycole used oil, oily rags and pads,
empty drums and cooking
oil drums on supply boat Omega Waste Management, W. Patterson, LA or ARC, New Iberia, LA 20 bbls/month recycle

Universal waste items Batteries, lamps, glass and
mercury-contaminated waste drums on supply boat Lamp Environmental, Hammond, LA 30 bbls/month disposed

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

Will you have additional wastes that are not permitted for discharge? If yes, fill in the appropriate rows. Projected generated wasteSECTION 8: AIR EMISSIONS INFORMATION

A. Emissions Worksheet and Screening Questions

Screening Questions for EP’s Yes No

Is any calculated Complex Total (CT) Emi ssion amount (in tons) associated with your proposed exploration activities more than 90% of the amounts calculated using the following formulas: CT = 3400D 2/3 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 H 2 S at concentrations greater than 20 parts per million (ppm)? x

Do you propose to flare or vent natura l 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 informatio n is compiled on the summary form of the two

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

do not need to include the entire set of worksheets.

Air Pollutant Plan

Emission 1

Amounts

(tons) Calculated Exemption 2

Amounts

(tons) Calculated Complex Total

Emission

Amounts 3

(tons)

PM 112.72 5194.8 NA

SO

x 64.63 5194.8 NA

NOx 3874.22 5194.8 NA

VOC 116.24 5194.8 NA

CO 845.28 98528.53 NA

1 For activities proposed in your EP or DOCD, list th e projected emissions calculated from the worksheets. 2 List the exemption amounts for your proposed activities calculated by using the form ulas 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

(1) Worksheets

Because the answers to all the questions set forth ab ove is “no”, further worksheets are not required. However, Shell is providing th e worksheets for your review.SECTION 9: OIL SPILLS INFORMATION

A. Oil Spill Response Planning

3⁄4 All the proposed activities and facilities in this EP will be covered by the Regional OSRP filed by Shell Offshore Inc (0689) in accordance with 30 CFR 250. Updated Regional OSRPs were filed with the BOEMRE on October 26, 2010; March 15, 2011; May 31, 2011 and July 6, 2011 and are pending approval. An OSRP Certification in accordance with 30 CFR 254.2 was submitted and accepted by the BOEMRE on July 11, 2011.

(ii) Spill Response Sites:
Primary Response Equipment Locations Preplanned Staging Location(s)

Galveston, TX ; Lake Charle s, LA ; Cameron, LA ; Fourchon ; LA Galveston, TX ; Lake Char les, LA ; Cameron, LA ; Fourchon ; LA

(iii) The names of the oil spill removal organizations (OSRO’s) under contract include Clean Gulf Associates (CGA), Marine Spill Response Company (MSRC), Clean Caribbean America (CCA), and OSRL/EARL.

(iv) Worst Case Scenario Determination

Category Regional OSRP EP

Type of Activity 1 Drilling Rig & Subsea

Installation Drilling Rig & Subsea

Installation

Facility Location (area/block) MC 762 WR 95

Facility Designation 2 Subsea well N Subsea well C

Distance to Nearest Shor eline (miles) 51 156

Volume 3

Storage tanks (total)
Flowlines (on facility)
Pipelines
Uncontrolled blowout (volume per day)

Total Volume N/A

N/A

N/A

449,000* BOPD

449,000 Bbls N/A

N/A

N/A

99,000** BOPD

99,000 Bbls

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

API Gravity(s) 4 27o 27o

*24 hour rate (359,000 BOPD 30 day average) **24 hour rate (79,000 BOPD 30 day average)

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 must be determined by using the dail y worst-case discharge volume determined using the guidance at 30 CFR 254.47(b). For DOCD’s, the daily worst-case discharge vo lume 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 October 26, 2010 for inclusion in our Regional OSRP.

Since Shell Offshore Inc has the capability to respond to the appropriate worst-case spill scenario included in its regional OSRP, submitted October 26, 2010, and since the worst-case scenario determined for our EP does not replace the appropriate worst-case scenario in our re gional OSRP, I hereby certify that Shell Offshore Inc has the capability to respond, to the maximum extent pr acticable, to a worst-case discharge, or a substantial threat 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 Table above and complete discussion in Section 2J.

2) Trajectory Analysis

Trajectories of a spill and the probability of it impacting a land segment have been projected utilizing information in the BOEMRE Oil Spill Risk Analysis Model (OSRAM) for the Central and

Western Gulf of Mexico available on the BOEMRE website using 30 day impact. Offshore areas along the trajectory between the source and land segm ent contact could be impacted. The land segment contact probabilities are shown in Table 9.C.1.

Area/Block OCS-G Launch

Area Land Segment Contact %

Exploratory

WR 95 47 Calhoun, TX -
Matagorda, TX 1

Brazoria, TX 1
Galveston, TX 2
Jefferson, TX 1
Cameron, LA 3
Vermilion, LA 1

Iberia, LA - St. Mary, LA -
Terrebonne, LA 1
Lafourche, LA -
Jefferson, LA -
Plaquemines, LA 1

Table 9.C.1 Probability of Land Segment Impact

C. Resource Identification

The locations identified in Table 9.C.1 are the highes t 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 Atmo spheric Administration (NOAA) Environmental Sensitivity Index (ESI) maps for the given land se gment. ESI maps provide a concise summary of coastal resources that are at risk if an oil spill o ccurs nearby. Examples of at-risk resources include biological resources (such as birds and shellfish be ds), sensitive shorelines (such as marshes and tidal flats), and human-use resources (such as public beaches and parks).In the event an oil spill occurs, ESI maps can he lp responders meet one of the main response objectives: reducing the environmental conseq uences of the spill and the cleanup efforts. Additionally, ESI maps can be used by planners to identify vulnerable locations, establish protection priorities, and identify cleanup strategies.

The following is a list of resources of special econ omic or environmental importance that potentially could be impacted by the WR 95 WCD scenario.

Onshore/Nearshore: Cameron Parish is identified as the most probable impacted Parish within the Gulf of Mexico for the Exploratory Worst Case Discharge. Cameron Parish is located in the

southwest corner of Louisiana and has a total area of 1,932 square miles of which, 1,313 square miles of it is land and 619 square miles is wate r. Cameron Parish includes four National Wildlife Refuges including the Cameron Prairie National Wild life Refuge, East Cove National Wildlife Refuge, Sabine National Wildlife Refuge and part of the La cassine National Wildlife Refuge. Key ESI maps for Cameron Parish and the legend are sh own in Figures 9.C.1through 9.C.10.

Offshore: An offshore spill may require an Essentia l 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 Contingenc y Plans (ACPs) were developed to provide a well coordinated response to oil disc harges and other hazardous releas es. The One Gulf Plan is specific to the Gulf of Mexico to advance the unity of po licy and effort in each of the Gulf Coast ACPs. Strategies used for the response to an oil spill regarding protection of identified resources are

detailed in the One Gulf Plan and relevant Gulf Coast ACP.

D. Worst Case Discharge Response

Shell will make every effort to respond to the WR 95 Worst Case Discharge as effectively as possible.

Applied Science Associates (ASA) conducted a de epwater blowout simulation for The Response Group to better determine subsurface and surface ev aporation and dispersion rates. Below is a table outlining the applicable evaporation and dispersion quantities:

Walker Ridge Block 95 Calculations

(BBLS)

i. 30 Day Average WCD = 79,000 bbls

ii. Subsurface dispersion – 25% (Water Depth = ~5,800) -19,750 bbls

iii. REMAINING WCD AFTER SUBSURFACE DISPERSION 59,250 bbls

iv. Surface dispersion and evaporation – 25% -14,813 bbls

TOTAL REMAINING ~44,400 bbls

Table 9.D.1 Oil Remaining After Subsurface and Surface DispersionShell has contracted OSROs to provide equipment, personnel, materials and support vessels as well as temporary storage equipment to be considered in order to cope with a WCD spill. Under adverse weather conditions, major response vessels and Tran srec skimmers are still effective and safe in sea states of 6-8 ft. If sea conditions prohibit safe me chanical recovery efforts, then natural dispersion and airborne chemical dispersant application (vis ibility & wind conditions permitting) may be the only safe and viable recovery option.

MSRC OSRV 8 foot seas

VOSS System 4 foot seas

Expandi Boom 6 foot seas, 20 knot winds

Dispersants Winds more than 25 knots,
Visibility less than 3 nautical miles, or
Ceiling less than 1,000 feet.

Table 9.D.2 Operational Limitations of Response Equipment

Upon notification of the spill, Shell would reques t 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 pr otection, and containment equipment. Following is a list of the contracted resources including de -rated recovery capacity, personnel, and estimated response times (procurement, load out, travel ti me to the site, and deployment). The Incident Commander or designee may contact other servic e companies if the Unified Command deems such services necessary to the response efforts.

Subsea Control and Containment: Shell, as a founding member of the Marine Well Containment Company (MWCC), will have access to a fully in tegrated subsea well control and containment system 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 will be addre ssed in Shell’s NTL10 submission at the time the

APD is submitted.

Mechanical Recovery (skimming): Response strategies include skimming utilizing available OSROs Oil Spill Response Vessels (OSRVs), Oil Spill Response Barges (OSRBs), ID Boats, and Quick

Strike OSRVs. There is a combined de-rated recovery rate capability of approximately 583,358 barrels/day. Temporary storage associated with the identified skimming and temporary storage equipment equals approximately 505,724 barrels.

De-rated Recovery Rate
(bopd) Storage
(bbls)

Offshore Recovery 476,365 277,000 Offshore Storage 211,500
Nearshore Recovery 106,993 17,224

Total 583,358 505,724

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

See attachment 9.D.4 Offshore On -Water Recovery Activation List
See attachment 9.D.5 Offshore On -Water Storage Activation List See attachment 9.D.6 Nearshore On-Water Recovery Activation ListOil Storage: The strategy for transferring, storing and di sposing of oil collected in these recovery zones is to utilize two 150,000-160,000 ton (dead weig ht) tankers mobilized by Shell (or any other tanker immediately available). The recovered oil wo uld 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, mo nitor, and target response to oil spills. Aircraft and spotters can be mobilized within hours of an event.

See attachment 9.D.7 Aerial Surveillance Activation List

Aerial Dispersant: Depending on proximity to shore and wa ter depth, dispersants may be a viable response option. If appropriate and approved, 4 to 5 sorties from three DC-3’s can be made within the first 12 hour operating day of the response. These aerial systems could disperse approximately 7,704 to 9,630 barrels of oil per da y. Additionally, 3 to 4 sorties from the BE90 King Air and 3 to 4 sorties from the Hercules C-130A within the first 12 hour operating day of the response could disperse 4,600 to 6,100 barrels of oil per day. For continuing disper sant operations, the CCA’s Aerial Dispersant Delivery System (ADDS) would be mobiliz ed. The ADDS has a dispersant spray capability of 5,000 gallons per sortie.

See attachment 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 mo nitors), skid mounted systems, or purpose-built boom arm spray systems. Vessels can apply dispersa nt within the first 12-24 hours of the response and continually as

directed.

See attachment 9.D.9 Offshore Boat Spray Dispersant Activation List

Subsea Dispersant: Shell has contracted with Wild Well Co ntrol for a subsea dispersant package. Subsea dispersant application has been found to be highly effective at reducing the amount of oil reaching the surface. Additional data collection, labo ratory tests and field tests will help in facilitating the optimal application rate and effectiveness num bers. For planning purposes, The system has the potential to disperse approximately 24,500 to 34,000 barrels of oil per day.

See attachment 9.D.10 Subsea Dispersant Package Activation List

In-Situ Burning: Open-water in-situ burning (ISB) also may be used as a response strategy, depending on the circumstances of the release. IS B services may be provided by the primary OSRO contractors. If appropriate condit ions exist and approvals are granted, one or multiple ISB task forces could be deployed offshore. Task forces typically consist of two to four fire teams, each with two vessels capable of towing fire boom, guide boom or tow line with either a handheld or aeriallydeployed oil ignition system. At least one suppo rt/safety boat would be present during active burning operations to provide logistics, safety an d 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 be fore being replaced. Fire intensity and weather will be the main determining factors for actual burns per system. Although the actual amount of oil that will be removed per burn is dependent on ma ny factors, recent data suggests that a typical burn might eliminate approximately 750 barrels. Fo r 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 an d remove up to ~12,000 bbl s/day. In-situ burning nearshore and along shorelines may be a possible option based on several conditions and with appropriate approvals, as outlined in Section 19 , In-situ Burn Plan (OSRP). In-situ burning along certain types of shorelines may be used to minimize physical damage where access is limited or if it is determined that mechanical/manual removal ma y cause a substantial negative impact on the environment. All safety considerations will be evalua ted. 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 contracted OSRO(s). There are potential limitations that need to be assessed prior to ISB operations. Some limitations include atmospheric and sea conditions; oil weathering; air quality impacts; safety of response workers; and risk of secondary fires.

See attachment 9.D.11 In-Situ Burn Equipment Activation ListShoreline Protection: If the spill went unabated, shoreline impact in St. Bernard or Plaquemines Parish, LA would depend upon existing environme ntal 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 surveillan ce and real time trajectories provided by The Response Group that depict areas of potential impact given actual sea and weather conditions. Strategies from the New Orleans, Louisiana Area Contingency Plan, The Response Group and Unified

Command would be consulted to ensure that envir onmental and special economic resources would be correctly identified and prioritized to ensure optimal protection. The Response Group shoreline response guides depict the protection response modes applicable for oil spill clean-up operations. Each response mode is schematically represented to show optimum deployment and operation of the equipment in areas of environmental concern. Supervisory personnel have the option to modify the deployment and operation of equipment allowi ng a more effective response to site-specific

circumstances.

See attachment 9.D.12 Shoreline Protection and Wildlife Support List

Wildlife Protection: If wildlife is threatened due to a spill, the contracted OSRO’s have resources available to Shell, which can be utilized to prot ect and/or rehabilitate wildlife. The resources under contract for the protection and rehabilitation of affected wildlife are in the following table:

See attachment 9.D.12 Shoreline Protection and Wildlife Support List

Estimated time to contain spill to the maximum extent practicable: Times to respond are

listed in Section 9 of the EP and estimated time to contain will be scenario driven and depend on the physical configuration of the spill source. The physical configuration of the release will dictate specific capabilities of response equipment and tool s. Therefore, the time to contain the spill can range from a few hours for BOP manipulation/a ctivation, to a few weeks for cap and contain equipment, and months for relief well execution.

New or unusual technology be employed, in regards to spill prevention, control, cleanup,

etc .: We will use our normal well design and cons truction processes with mu ltiple barrier approach as well as new stipulations mandated by NTL 05; response techniques will utilize new learnings from Macondo response to include in-situ burning and subsea dispersant application. In addition, mechanical recovery advancements are underway to incorporate utilization of Koseq arms outfitted on barges, conversion of Platform Support Vessel s for Oil Spill Response, and inclusion of nighttime spill detection radar to improve tracking capabilit ies (X-Band radar, Infrared sensing, etc.).

(9c) Modeling Report

Shell did not model a potential oil or hazardous substance spill.Figure 9.C.1 Environmental Sensitivity Index Map LegendFigure 9.C.2 Texas Point ESI MapFigure 9.C.3 Smith Bayou ESI MapFigure 9.C.4 Johnsons ESI MapFigure 9.C.5 Peveto Beach ESI MapFigure 9.C.6 Holly Beach ESI MapFigure 9.C.7 Cameron ESI MapFigure 9.C.8 Grand Bayou ESI MapFigure 9.C.9 Creole ESI MapFigure 9.C.10 Hackberry Beach ESI MapTable 9.D.4 Offshore On-Water Recovery Activation ListTable 9.D.4 Offshore On-Water Recovery Activation List (continued)Table 9.D.4 Offshore On-Water Recovery Activation List (continued)Table 9.D.4 Offshore On-Water Recovery Activation List (continued)Table 9.D.5 Offshore On-Water Storage Activation ListTable 9.D.6 Nearshore On-Water Recovery Activation List

31943Table 9.D.6 Nearshore On -Water Recovery Activation List (continued)Table 9.D.6 Nearshore On -Water Recovery Activation List (continued)Table 9.D.6 Nearshore On -Water Recovery Activation List (continued)Table 9.D.7 Aerial Surveillance Activation ListTable 9.D.8 Offshore Aerial Dispersant Activation ListTable 9.D.9 Offshore Boat Spray Dispersant Activation ListTable 9.D.10 Subsea Dispersant Package Activation ListTable 9.D.11 In-Situ Burn Equipment Activation ListTable 9.D.11 In-Situ Burn Equipment Activation List (continued)Table 9.D.12 Shoreline Protection and Wildlife Support ListSECTION 10: Environmental Monitoring Information

A. Monitoring Systems

A rig based Acoustic Doppler Current Profiler (ADCP) is used to continuously monitor the current beneath the Rig. Metocean conditions such as sea states, wind speed, ocean currents, etc. will also be continuously

monitored

B. Incidental Takes

No incidental takes are anticipated. Shell implements the mitigation measures and monitors for incidental takes of protected species according to the following notices to lessees and operators from the Minerals Management Service:

NTL No.2007-G03 “Marine Trash and De bris Awareness and Elimination”

NTL No.2007-G04 “Vessel Strike Avoidance and Injured/Dead Protected Species Reporting”

C. Flower Garden Banks National Marine Sanctuary

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

Banks and Stetson Bank.SECTION 11: Lease Stipulations Information

OCS-G 31943 is not a part of any Biological Sensitive Area, Military Warning Area, high Archeological probability area, or Shipping Fairway.

Lease Stipulation No. 6, Protected Species, is addressed in the following sections of this plan:

Section 6h, Threatened or endangered species, cr itical habitat, and marine mammal information Section 10b, Environmental Monitoring Information, Incidental takes Section 12b, Environmental Mitigation Measures Information, Incidental takes Section 18, Environmen tal Impact Assessment

SECTION 12: Environmental M itigation Measure Information

A. Impacts to Marine and coastal environments

The proposed action will implement mitigation measures requ ired by laws and regulations, including all applicable Federal & State requirements concerning air emissions, discharges to water, and solid waste disposal, as well as any additional permit requirements and Shell policies. Proj ect activities will be conducted in accordance with the Regional Oil Spill Response Plan. The EIA attached as Section 18 to this plan discusses impacts and mitigation

measures.

B. Incidental Takes

We do not anticipate any incidental takes related to th e proposed operations. Shell implements the mitigation measures and monitors for incidental takes of protected species according to the following notices to lessees and operators from the Minerals Management Service:

NTL No.2007-G03 “Marine Trash and De bris 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 Related Facilities and Operations Information, transportation systems, & produced liquid hydrocarbon transportation vessels are not included in this EP as such information is only necessary in the case of

DOCDs.SECTION 14: Support Vessels and Aircraft Information

A. General

Type Maximum Fuel Tank Storage Capacity (Bbls) Maximum No. In Area at Any

Time Trip Frequency or

Duration

Crew Boats 1040 2 Twice per week Offshore Support Vessels 9750 3 165 days/well 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 100,000 gal. 1 week Port Fourchon to MC 984

C. Drilling Fluids Transportation Type of Material Quantity Being Transported Transportation Method Dry Bulk (Cement, Barite, Gel) 12,000 sx max combined Below deck dry bulk tanks

onboard OSV Synthetic-base drilling fluids 11,000 bbls max per voyage Tanks below deck onboard

OSV

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

Boothville PHI Heliport Boothville, LA Existing

C-Port II Fourchon, LA Existing

The existing onshore support base for air transportation will be PHI Heliport in Boothville, LA located at 38963 Highway 23. The existing onshore base for installation water traffic will be the C-Port II located at Port Fourchon Terminal located on Bayou LaFourche, south of Leesville, LA approximately three miles from the Gulf

of Mexico.

B. Support Base Construction or Expansion

This Section does not apply to this EP as Shell does not plan to cons truct a new onshore support base or expand an existing one to accommodat e the activities proposed in this EP.

C. Support Base Construction or Expansion Timetable

This Section does not apply to this EP as Shell does not plan to cons truct a new onshore support base or expand an existing one to accommodat e the activities proposed in this EP.

D. Waste Disposal

See Table 7B.

SECTION 16: Sulphur Operations Information

Information regarding Sulfur Operations Information is no t included in this EP as such information is only necessary in the case of DOCDs.SECTION 17: Coastal Zone Manage ment Act (CZMA) Information

Concurrence with Louisiana CZM was obtained in Plan N-9410 for lease OCS-G 31943 in September 2009.

LOUISIANA

COASTAL ZONE MANAGEMENT

CONSISTENCY CERTIFICATION

REVISED EXPLORATION PLAN Type of Plan

WALKER RIDGE BLOCK 95

OCS-G 31943

The proposed activities described in detail in this Pl an will comply with Louisiana's State and Local Coastal Resources Management Act of 1978, Coastal Resources Program, and Coastal Area Management Enforceable

Policies.

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

SHELL OFFSHORE INC. (SOI) Operator

_____________________________________________ Sylvia A. Bellone Certifying Official

04/26/2011

Date

### TEXAS

COASTAL ZONE MANAGEMENT

CONSISTENCY CERTIFICATION

Revised Exploration Plan Type of Plan

WALKER RIDGE BLOCK 95

OCS-G 31943



### The proposed activities described in detail in this Plan wi ll comply with Texas State and Local Coastal Resources Management Act of 1978, Coastal Reso urces Program, and Coas tal Area Management Enforceable Policies.

SHELL OFFSHORE INC. (SOI) Operator

____________________________ Sylvia A. Bellone Certifying Official

04/26/2011

DateCoastal Zone Management Consistency Information

For the State of Texas

In accordance with Subpart E of 15 CFR 903 “Consisten cy for Outer Continental Shelf (OCS) Exploration, Development and Production Activities” and as required by 15 CFR 930.58, Shell Offshore INC (SOI) is hereby providing the following information in support of the En vironmental Impact Analysis submitted as Attachment 18 of our Supplemental EP. 15 CFR 930.58 identifies nece ssary data and information to be furnished to the State agency. The information is as follows:

(a) CONSISTENCY CERTIFICATION A Coastal Zone Consistency Certificatio n for activities that affect the State of Texas is provided above.

OTHER INFORMATION

A detailed description of the proposed activities, coasta l effects, and comprehensive information sufficient to support this Consistency Certification is presented in the above-mentioned EP. As per NTL 2008-G04, the following items have been identified as being required:

• A discussion of the method of disposal of wastes an d discharges is provided in Section 7 of the abovementioned EP.

• Oil Spill Information is provided in Section 9 of th e above-mentioned EP. All operations are covered by Shell Offshore Inc's Regional Oil Spill Response Plan, which is being upda ted with the BOEM. The 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 relevant enforceabl e policies of the Texas’ Co astal 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 area s. The proposed activities are explorative in nature, so no facility construction is proposed . The proposed activities are located approximately 170 miles from the Texas shoreline; therefore we expect no adverse impa cts to CNRAs or beach access and use rights of the public. All activities shall be conducted in a manner th at 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 Wast e from Oil and Gas Exploration and Production

Activities No discharge of wastewater or disposal of waste from the proposed activities will occur in the Texas’ coastal zone, therefore no impact to Texa s’ coastal waters is expected.

(Category 4) Construction and Operation of Solid Wast e 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 utilized to prevent the release of pollutants or toxic substances into the enviro nment. All involved vessels and facilities are designed to be capable of prompt response an d adequate removal of accidental disc harges of oil. In addition, the proposed activities are 170 miles from the Texas shor e; therefore no damages to natural resources are expected as the result of an unauthorize d 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 170 miles from the Texas 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 critical area; therefore no effects to Texas’ coastal zone are expected. The activity will not jeopardize the conti nued existence of species listed as endangered or threatened, and will not result in likelihood of the destru ction 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 prop osed 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 an y construction projects in critical dune areas or areas adjacent 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 do not include any alteration or disturbance of a coastal historic 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 do not includ e any transportation construction projects within the coastal zone; therefore, no impacts to Texas’ coastal zone are expected.(Category 17)

Emission of Air Pollutants The proposed activities shall be carried out in conforma nce with applicable air quality laws, standards, and regulations. Emissions from the proposed activities are not expected to have 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 170 miles from the Texas shore and will be within the exemption limits set by BOEM, therefore, no impact s to Texas’ coastal zone is expected.

(Category 18) Appropriations of Water The proposed activities do not include the impoundment or diversion of stat e water, therefore, no impacts to Texas’ coastal zone is expected.

(Category 20) Marine Fishery Management The proposed activities are located approximately 170 m iles from the Texas shore and are not expected to have any effect on marine fishery management or fisher y 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 pr ogram and shall comply with all relevant rules and regulations. No activities are pla nned within any critical areas. Activities will be carried out avoiding unnecessary conflicts with other uses of the vicinity.

### SECTION 18: Environmental Impact Analysis (EIA)

See following report prepared by CSA.SECTION 19: Administrative Information

A. Exempted Information Description (Public Information Copies Only)

The following attachments are excluded from the public information copies of typical plans:

1b. OCS Plan Information form – Bottom hole locations & proposed total depth 2j. Blowout Scenario – confidential information for NTL 2010 N06 calculation 3a. Geologic Description 3b. Structure Contour Maps 3c. Interpreted 2D or 3D seismic line(s) 3d. Cross Section(s) 3e. Shallow Hazards Report

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

3⁄4 Geologic & Stratigraphic Assessment of Walker Ridge Blocks 95 & 139, prepared by GEMS for Shell Offshore Inc, dated February 19, 2009, project No. 1008-1564.