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-05089

Type - Revised Exploration Plan

Lease(s) - OCS-G32700 Block - 675 Walker Ridge Area OCS-G32704 Block - 719 Walker Ridge Area

Operator - Eni US Operating Co. Inc.

Subsea Wells A, B, C, D, E, & G (WR 719) and F (WR 675)

Not Found

Attached is a copy of the subject plan for public comments on issues that
should be addressed in an Environmental Assessment.

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

Karen Dunlap

Plan Coordinator Description -

Rig Type - Subject: From: June 7, 2011

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# REVISED

EXPLORATION PLAN (Control No. R-5089)

WALKER RIDGE BLOCKS 675 AND 719
LEASES OCS-G 32700 & 32704

PUBLIC INFORMATION COPY

Submitted by:

eni us operating co. inc.

### ENI US OPERATING CO. INC.

REVISED EXPLORATION PLAN

LEASES OCS-G 32700 & 32704

WALKER RIDGE 675 & 719

SECTION A............................................. Plan Contents..................................Page 1

SECTION B..................................... General Information...............................Pages 2-3

SECTION C................ Geological, Geophysical Information....................................Pa ge 4

SECTION D.......................................... H2S Information..................................Page 5

SECTION E............. Biological, Physical and Socioeconomic Information... ..................Page 6

SECTION F..................... Wastes and Discharge Information.................................Page 7

SECTION G.............................. Air Emissions Information...................................Page 8

SECTION H.................................... Oil Spills Information............................Page 9 - 21

SECTION I................. Environmental Monitoring Information................................Pag e 22

SECTION J........................... Lease Stipulations Information...............................Page 23

SECTION K............... Environmental Mitigation Measures Information.............. ......Page 24

SECTION L ...............Support Vessels and Aircraft Information.................. ..............Page 25

SECTION M............... Onshore Support Facilities Information............................... Page 26

SECTION N........... Coastal Zone Management Act (CZMA) Information............... ....Page 27

SECTION O........................... Environmental Impact Analysis.............................Page 28

SECTION P................................ Administrative Information.............................Page 29Eni US Operating Co. Inc. Page 1

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION A
PLAN CONTENTS

(a) Plan Information Form No wells have been drilled at this time, a previous ly approved Exploration Plan, Control No. N-9509 co vered the drilling and completion of Well Locations “A” to “G ”, no additional changes to this section.

(b) Location Previously provided and approved under Plan Control No. N-9509, under “Contents of Plan” item (B).

(c) Safety and Pollution Prevention Features All reference to this section was previously provid ed and approved under Plan Control No. N-9509, unde r “Contents of Plan” item (C) only addition is Eni will be util izing a subsurface BOP stack to conduct the drillin g operations under this plan.

(d) Storage Tanks and/or Production Vessels Previously provided and approved under Plan Control No. N-9509, under “Contents of Plan” item (D) and will

remain the same.

(e) Pollution Prevention Measures Pollution prevention measures include installation of curbs, gutters, drip pans, and drains on drillin g deck areas to

collect all contaminants and debris.

(f) Additional Measures Eni does not propose additional safety, pollution p revention, or early spill detection measures beyond those required by 30 CFR 250.U.S. Department of the Interior OMB Control Numbe r: 1010-0151 Minerals Management Service OMB Approval Expires: 12/31/2011 

## OCS PLAN INFORMATION FORM

MMS Form MMS-137 (July 2005 – Supersedes all previous editions of form MMS-137, w hich may not be used.)


### ATTACHMENT A-1 GENERAL INFORMATION

Type of OCS Plan: X Revised Exploration Plan (EP) – R-5089 Development Operations Coordination Document (DOCD )

Company Name: Eni US Operating Co., Inc. BOEMRE Ope rator Number: 02782

Address: 1201 Louisiana, Suite 3500 Contact Person: Brenda Montalvo

Houston, Texas 77002 Phone Number: (713) 393-6259

Email Address:

Lease(s):G32700/32704 Area: WR Block(s): 675/719 Pr oject Name (If Applicable): PHINISI

Objective(s): Oil Gas Sulphur Salt Onshore Base: Fourchon, LA Distance to Closest Land (Miles): 193

Description of Proposed Activities (Mark all that a pply)

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 prot ection structure Installation of satellite structure

Installation of subsea wellheads and/or manifold s Commence production
Installation of lease term pipelines Other (Specify and describe)
Have you submitted or do you plan to submit a Conse rvation Information Document to accompany this plan ? Yes X No
Do you propose to use new or unusual technology to conduct your activities? Yes X No
Do you propose any facility that will serve as a ho st facility for deepwater subsea development? Yes X No

Do you propose any activities that may disturb a BO EMRE-designated high-probability archaeological are a? Yes X No
Have all of the surface locations of your proposed activities been previously reviewed and approved by BOEMRE? X Yes No
Tentative Schedule of Proposed Activities

Proposed Activity Start

Date End

Date No. of Days

Drill Location A 01/01/11 05/01/11 120 days

Drill Location B 11/01/11 02/29/12 120 days

Drill Location C 11/01/12 03/01/13 120 days

Drill Location D 11/01/13 03/01/14 120 days
Complete Locations A,B,C & D 05/01/14 12/31/14 240 days
Drill Locations E, F, & G contingent on Locations A , B, C, & D 11/01/15 10/26/16 360 days
Complete Locations E, F, & G Contingent on Location s A, B, C & D 01/01/17 06/30/17 180 days

Description of Drilling Rig Description of Production Platform

Jackup Drillship Caisson Tension leg platform
Gorilla Jackup Platform rig Well protector Compliant tower

Semisubmersible Submersible Fixed platform Guyed tower

DP Semisubmersible Other (Attach Description) Subsea manifold Floating production system
Drilling Rig Name (If Known): Spar Other (Attach description)
Description of Lease Term Pipelines

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

### OCS PLAN INFORMATION FORM (CONTINUED) 

### Include one copy of this page for each proposed wel l/structure



## MMS Form MMS-137 (July 2005 – Supersedes all previous editions of form MMS-137, w hich may not be used.) Proposed Well/Structure Location

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

Anchor Radius (if applicable) in feet: N/A Yes No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 32704

Area Name Walker Ridge

Block No. 719

N/S Departure: 6634’ FNL Blockline Departures (in feet) E/W Departure: 7410’ FWL

X: 2,225,010’ Lambert X-Y
coordinates Y: 9529046’

Latitude: 26° 15’ 00.824” Latitude/ Longitude Longitude: -91° 12’ 57.423”

TVD (Feet): MD (Feet): Water Depth (Feet): 6838’

Anchor Locations for Drilling Rig or Construction B arge (If anchor radius supplied above, not necessar y)

Anchor Name

or No. Area Block X Coordinate Y Coordinate Length of Anchor
Chain on Seafloor
X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chap ter 35) requires us to inform you that BOEMRE collects this information as part of an applicant’s Exploration Plan or Deve lopment Operations Coordination Document submitted for BOEMRE approval . We use the information to facilitate our review a nd data entry for OCS plans. We will protect proprietary data acc ording to the Freedom of Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to respond to, a collection of informa tion unless it displays a currently valid Office of Management and Budget C ontrol Number. The use of this form is voluntary. T he public reporting burden for this form is included in the b urden for preparing Exploration Plans and Developme nt Operations
Coordination Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, gathering and maintaining data, and c ompleting and reviewing the form. Direct comments r egarding the burden estimate or any other aspect of this form to the In formation Collection Clearance Officer, Mail Stop 4 230, Bureau of Ocean Energy Management Regulation & Enforcement, 1849 C Street, N.W., Washington, DC 20240.

### OCS PLAN INFORMATION FORM (CONTINUED) 

### Include one copy of this page for each proposed wel l/structure



## MMS Form MMS-137 (July 2005 – Supersedes all previous editions of form MMS-137, w hich may not be used.) Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Location B Sub sea Completion

Anchor Radius (if applicable) in feet: N/A Yes No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 32704

Area Name Walker Ridge

Block No. 719

N/S Departure: 4462’ FNL Blockline Departures (in feet) E/W Departure: 5921’ FWL

X: 2,223,521’ Lambert X-Y
coordinates Y: 9,531,218’

Latitude: 26° 15’ 22.538” Latitude/ Longitude Longitude: -91° 13’ 13.448”

TVD (Feet): MD (Feet): Water Depth (Feet): 6,829 ’

Anchor Locations for Drilling Rig or Construction B arge (If anchor radius supplied above, not necessar y)

Anchor Name

or No. Area Block X Coordinate Y Coordinate Length of Anchor
Chain on Seafloor
X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chap ter 35) requires us to inform you that BOEMRE collects this information as part of an applicant’s Exploration Plan or Deve lopment Operations Coordination Document submitted for BOEMRE approval . We use the information to facilitate our review a nd data entry for OCS plans. We will protect proprietary data acc ording to the Freedom of Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to respond to, a collection of informa tion unless it displays a currently valid Office of Management and Budget C ontrol Number. The use of this form is voluntary. T he public reporting burden for this form is included in the b urden for preparing Exploration Plans and Developme nt Operations
Coordination Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, gathering and maintaining data, and c ompleting and reviewing the form. Direct comments r egarding the burden estimate or any other aspect of this form to the In formation Collection Clearance Officer, Mail Stop 4 230, Bureau of Ocean Energy Management Regulation & Enforcement, 1849 C Street, N.W., Washington, DC 20240.

### OCS PLAN INFORMATION FORM (CONTINUED) 

### Include one copy of this page for each proposed wel l/structure



## MMS Form MMS-137 (July 2005 – Supersedes all previous editions of form MMS-137, w hich may not be used.) Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Location C Sub sea Completion

Anchor Radius (if applicable) in feet: Yes No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 32704

Area Name Walker Ridge

Block No. 719

N/S Departure: 494’ FNL Blockline Departures (in feet) E/W Departure: 832’ FWL

X: 2218432’ Lambert X-Y
coordinates Y: 9535186’

Latitude: 26° 16’ 02.525” Latitude/ Longitude Longitude: -91° 14’ 08.745”

TVD (Feet): MD (Feet): Water Depth (Feet): 6,907 ’

Anchor Locations for Drilling Rig or Construction B arge (If anchor radius supplied above, not necessar y)

Anchor Name

or No. Area Block X Coordinate Y Coordinate Length of Anchor
Chain on Seafloor
X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chap ter 35) requires us to inform you that BOEMRE collects this information as part of an applicant’s Exploration Plan or Deve lopment Operations Coordination Document submitted for BOEMRE approval . We use the information to facilitate our review a nd data entry for OCS plans. We will protect proprietary data acc ording to the Freedom of Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to respond to, a collection of informa tion unless it displays a currently valid Office of Management and Budget C ontrol Number. The use of this form is voluntary. T he public reporting burden for this form is included in the b urden for preparing Exploration Plans and Developme nt Operations
Coordination Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, gathering and maintaining data, and c ompleting and reviewing the form. Direct comments r egarding the burden estimate or any other aspect of this form to the In formation Collection Clearance Officer, Mail Stop 4 230, Bureau of Ocean Energy Management Regulation & Enforcement, 1849 C Street, N.W., Washington, DC 20240.

### OCS PLAN INFORMATION FORM (CONTINUED) 

### Include one copy of this page for each proposed wel l/structure



## MMS Form MMS-137 (July 2005 – Supersedes all previous editions of form MMS-137, w hich may not be used.) Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Location D Sub sea Completion

Anchor Radius (if applicable) in feet: N/A Yes No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 32704

Area Name Walker Ridge

Block No. 719

N/S Departure: 6,468’ FNL Blockline Departures (in feet) E/W Departure: 2,978’ FWL

X: 2,220,578’ Lambert X-Y
coordinates Y: 9,529,212’

Latitude: 26°15’ 03.071” Latitude/ Longitude Longitude: -91° 13’ 46.072”

TVD (Feet): MD (Feet): Water Depth (Feet): 6,923 ’

Anchor Locations for Drilling Rig or Construction B arge (If anchor radius supplied above, not necessar y)

Anchor Name

or No. Area Block X Coordinate Y Coordinate Length of Anchor
Chain on Seafloor
X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chap ter 35) requires us to inform you that BOEMRE collects this information as part of an applicant’s Exploration Plan or Deve lopment Operations Coordination Document submitted for BOEMRE approval . We use the information to facilitate our review a nd data entry for OCS plans. We will protect proprietary data acc ording to the Freedom of Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to respond to, a collection of informa tion unless it displays a currently valid Office of Management and Budget C ontrol Number. The use of this form is voluntary. T he public reporting burden for this form is included in the b urden for preparing Exploration Plans and Developme nt Operations
Coordination Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, gathering and maintaining data, and c ompleting and reviewing the form. Direct comments r egarding the burden estimate or any other aspect of this form to the In formation Collection Clearance Officer, Mail Stop 4 230, Bureau of Ocean Energy Management Regulation & Enforcement, 1849 C Street, N.W., Washington, DC 20240.

### OCS PLAN INFORMATION FORM (CONTINUED) 

### Include one copy of this page for each proposed wel l/structure



## MMS Form MMS-137 (July 2005 – Supersedes all previous editions of form MMS-137, w hich may not be used.) Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Location E Sub sea Completion

Anchor Radius (if applicable) in feet: Yes No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 32704

Area Name Walker Ridge

Block No. 719

N/S Departure: 4,606’ FNL Blockline Departures (in feet) E/W Departure: 858’ FWL

X: 2,218,458’ Lambert X-Y
coordinates Y: 9,531,074’

Latitude: 26° 15’ 21.798” Latitude/ Longitude Longitude: -91° 14’ 09.075”

TVD (Feet): MD (Feet): Water Depth (Feet): 6,919 ’

Anchor Locations for Drilling Rig or Construction B arge (If anchor radius supplied above, not necessar y)

Anchor Name

or No. Area Block X Coordinate Y Coordinate Length of Anchor
Chain on Seafloor
X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chap ter 35) requires us to inform you that BOEMRE collects this information as part of an applicant’s Exploration Plan or Deve lopment Operations Coordination Document submitted for BOEMRE approval . We use the information to facilitate our review a nd data entry for OCS plans. We will protect proprietary data acc ording to the Freedom of Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to respond to, a collection of informa tion unless it displays a currently valid Office of Management and Budget C ontrol Number. The use of this form is voluntary. T he public reporting burden for this form is included in the b urden for preparing Exploration Plans and Developme nt Operations
Coordination Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, gathering and maintaining data, and c ompleting and reviewing the form. Direct comments r egarding the burden estimate or any other aspect of this form to the In formation Collection Clearance Officer, Mail Stop 4 230, Bureau of Ocean Energy Management Regulation & Enforcement, 1849 C Street, N.W., Washington, DC 20240.

### OCS PLAN INFORMATION FORM (CONTINUED) 

### Include one copy of this page for each proposed wel l/structure



## MMS Form MMS-137 (July 2005 – Supersedes all previous editions of form MMS-137, w hich may not be used.) Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Location F Sub sea Completion

Anchor Radius (if applicable) in feet: N/A Yes No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 32700

Area Name Walker Ridge

Block No. 675

N/S Departure: 2,933’ FSL Blockline Departures (in feet) E/W Departure: 6,515’FEL

X: 2,226,926’ Lambert X-Y
coordinates Y: 9,538,613’

Latitude: 26° 16’ 35.309” Latitude/ Longitude Longitude: -91° 12’ 34.929”

TVD (Feet): MD (Feet): Water Depth (Feet): 7,031 ’

Anchor Locations for Drilling Rig or Construction B arge (If anchor radius supplied above, not necessar y)

Anchor Name

or No. Area Block X Coordinate Y Coordinate Length of Anchor
Chain on Seafloor
X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chap ter 35) requires us to inform you that BOEMRE collects this information as part of an applicant’s Exploration Plan or Deve lopment Operations Coordination Document submitted for BOEMRE approval . We use the information to facilitate our review a nd data entry for OCS plans. We will protect proprietary data acc ording to the Freedom of Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to respond to, a collection of informa tion unless it displays a currently valid Office of Management and Budget C ontrol Number. The use of this form is voluntary. T he public reporting burden for this form is included in the b urden for preparing Exploration Plans and Developme nt Operations
Coordination Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, gathering and maintaining data, and c ompleting and reviewing the form. Direct comments r egarding the burden estimate or any other aspect of this form to the In formation Collection Clearance Officer, Mail Stop 4 230, Bureau of Ocean Energy Management Regulation & Enforcement, 1849 C Street, N.W., Washington, DC 20240.

### OCS PLAN INFORMATION FORM (CONTINUED) 

### Include one copy of this page for each proposed wel l/structure



## MMS Form MMS-137 (July 2005 – Supersedes all previous editions of form MMS-137, w hich may not be used.) Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or structure, reference previous name): Location G Sub sea Completion

Anchor Radius (if applicable) in feet: N/A Yes No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 32704

Area Name Walker Ridge

Block No. 719

N/S Departure: 3,726’ FNL Blockline Departures (in feet) E/W Departure: 1,933’ FEL

X: 2,234,507’ Lambert X-Y
coordinates Y: 9,531,954’

Latitude: 26° 15’ 28.732” Latitude/ Longitude Longitude: -91° 11’ 45.628”

TVD (Feet): MD (Feet): Water Depth (Feet): 7,031’

Anchor Locations for Drilling Rig or Construction B arge (If anchor radius supplied above, not necessar y)

Anchor Name

or No. Area Block X Coordinate Y Coordinate Length of Anchor
Chain on Seafloor
X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

X = Y =

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chap ter 35) requires us to inform you that BOEMRE collects this information as part of an applicant’s Exploration Plan or Deve lopment Operations Coordination Document submitted for BOEMRE approval . We use the information to facilitate our review a nd data entry for OCS plans. We will protect proprietary data acc ording to the Freedom of Information Act and 30 CFR 250.196. An agency may not conduct or sponsor, and a person is not required to respond to, a collection of informa tion unless it displays a currently valid Office of Management and Budget C ontrol Number. The use of this form is voluntary. T he public reporting burden for this form is included in the b urden for preparing Exploration Plans and Developme nt Operations
Coordination Documents. We estimate that burden to average 580 hours per response, including the time for reviewing instructions, gathering and maintaining data, and c ompleting and reviewing the form. Direct comments r egarding the burden estimate or any other aspect of this form to the In formation Collection Clearance Officer, Mail Stop 4 230, Bureau of Ocean Energy Management Regulation & Enforcement, 1849 C Street, N.W., Washington, DC 20240.Eni US Operating Co. Inc. Page 2

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION B
GENERAL INFORMATION

(a) Applications and Permits No additional applications or permits from other ag encies are required at this time to be submitted an d approved other than an Application for Permit to Drill (APD) to the appropriate BOEMRE District.

(b) Drilling Fluids

Type of Drilling Fluid Estimated Volume of Drilling Fluid to be Used per

Well Water-based (seawater, freshwater, barite) 25000 Oil-based (diesel, minerals, oil) 0 Synthetic-based (internal olefin, ester) 8000

(e) New or Unusual Technology

Eni does not propose to use any new or unusual technolo gy to carry out the proposed exploration activities

.

(f) Bonding Statement The bond requirements for the activities and facili ties proposed in this EP are satisfied by areawide development bond, furnished and maintained according to 30 CFR 256, subpart I; NTL No. 2000-G16, "Guidelines for G eneral Lease Surety Bonds;" and additional security under 30 CFR 256.53(d) and National NTL No. 2008-N07, “Supplemental Bond Procedures.”

(g) Oil Spill Financial Responsibility Oil Spill Financial Responsibility coverage will be obtained under Eni US Operating Co. Inc., BOEMRE c ompany number 02782 for the activities proposed under this Exploration Plan according to 30 CFR Part 253; and NTL No. 2008-N05, "Guidelines for Oil Spill Financial Respo nsibility for Covered Facilities".

(h) Deepwater Well Control Statement Eni Us Operating Co. Inc., BOEMRE company number 02 782, has the financial capability to drill a relief well and conduct other emergency well control operations

.

(j) Blowout Scenario Should a blow-out occur, the formation types in thi s area do not tend to bridge over of their own acco rd. Eni will use
sub-surface BOPs with accumulator bottles attached to the BOP skid package. Sufficient accumulator bottles to activate the BOPs are located on the BOP skid packa ge. The control lines are fed from rig to the sub-s urface control system which activates the BOP. Two activation sys tems exist to allow rig floor activation or remote activation of
the BOPs.

If the subsea BOP and wellhead remain intact but do not close upon activation from the rig, ROVs locat ed either on the rig or a stand-by boat shall be launched to att empt to close the BOPs by pumping into the secondar y intervention devices located on the BOP within twelve (12) hours , unless the area is deemed unsafe. Once the area i s deemed safe to enter, ships will launch ROVs to perform th e intervention actions.

The present calculated release from the wellbore is 5,194 Bbls of oil per day and 1.2 MM cubic feet of gas per day. If a relief well to kill the original well was requ ired; it would be expected to take 80 days.

An approximate breakdown of this time with only DP rigs would include:

Time of obtain rig, rig to temporarily abandon well they are presently on, and move to location of blo w-out: 10 days

Drill to depth 50 days Drill to intersect point 10 daysEni US Operating Co. Inc. Page 3

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) Drill Intersection 7 days Kill with downhole kill procedure 3 days

Therefore a total release if the well did not bridg e over would be 415,520 barrels of oil and 96 MM cu bic feet of gas.

There are no structures in the area near this locat ion. Therefore, no platform could be used of relief well operations. Eni would use only Dynamically Positioned (DP) rigs for the relief well operations. Eni would use two (2) to possibly three (3) rigs to ensure the blow-out well could be brought under control even if one relief well encountered problems while drilling.

Eni follows the BOEMRE schedule for BOP tests and e xpects and demands that BOPs are kept functional by the contractors. Eni will shut down operations for any repairs needed on well control devices anytime they are not considered functional and safe. Eni uses Company re presentatives with many years of experience for dri lling operations and they constantly communicate with the OIM on the rig to ensure the safety of all personn el and equipment. All Company representatives maintain Wel l Control Certificates and are trained in well cont rol.

Eni uses multiple liners to cover potential product ion zones to reduce the risk of loss of well integr ity.

Eni foresees no restrictions for DP rigs to work in the area to perform well intervention and control. Eni would review and hire DP rigs to prevent usage of mooring systems therefore saving time to bring the well un der control. Since the original well bore would be considered un -usable; Eni would drill from some distance to prev ent either oil or gas from the damaged well, from affected the int ervention activities. Flammable meters on the inter vention rigs would be supplemented with additional detectors on the rig to ensure protection of personnel and equip ment. If detectors registered high levels of LELs, the rigs would be shut down during that time to protect pers onnel and the equipment.

Eni maintains additional materials on board the rig in order to “weight-up” the mud system to control any upsets or well control issues. Mud pits are monitored constan tly by personnel when operations are ongoing. In ad dition, automatic alarms are located in the pits and will s ound if pits receive abnormal amounts of return flu ids to alert of possible flow control problems. Personnel on the ri g floor are trained to monitor the systems and resp ond immediately if a problem is noted or if alarms soun d and will take all necessary steps including opera ting the BOPs

to maintain control of the well

.Eni US Operating Co. Inc. Page 4

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION C
GEOLOGICAL AND GEOPHYSICAL INFORMATION

The information for this section has not changed an d was discussed under an approved Initial Explorati on Plan, Control No. N-9509, pages 4 and 5 under Geological and Geophysical Information.Eni US Operating Co. Inc. Page 5

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION D
HYDROGEN SULFIDE INFORMATION

The information for this section has not changed an d was discussed under an approved Initial Explorati on Plan, Control No. N-9509, page 6, Hydrogen Sulfide Inform ation.Eni US Operating Co. Inc. Page 6

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION E BIOLOGICAL, PHYSICAL AND SOCIOECONOMIC INFORMATION

The information for this section has not changed and was discussed under an approved Initia l Exploration Plan, Control No. N-9509, pages 8 and 9, Biological, Phys ical and Socioeconomic Information.Eni US Operating Co. Inc. Page 

### 7

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION F
WASTES AND DISCHARGES INFORMATION

Projected Generated Wastes and Projected Ocean Disc harges

TABLE 1. WASTES YOU WILL GENERATE, TREAT AND DOWNHOLE DISPOS E OR DISCHARGE TO
THE GOM

All discharges associated with operations proposed in this Exploration Plan will be in accordance with regulations implemented by the Bureau of Ocean Ener gy Management, Regulation & Enforcement (BOEMRE), U. S. Coast Guard (USCG) and the U.S. Env ironmental Protection Agency (EPA).please specify if the amount reported is a total orper well amountProjected generated wasteProjected ocean dischargesType of WasteComposition Projected Amount Discharge rate Discharge Method Answeryes or noWill drilling occur ? If yes, you should list muds and cuttingsEXAMPLE: Cuttings wetted with synthetic based fluidCuttings generated whileusing synthetic based drilling X bbl/well X bbl/day/well discharge overboard NoWater-based drilling fluidbarite, additives45,0001,000 discharge overboardNoCuttings wetted with water-based fluidCuttings generated while using water based drilling fluid.5,000500discharge overboardNoCuttings wetted with synthetic-based fluidcuttings generated whle usingsynthetic based drilling fluid7,000200discharge overboardNoBrinebrine21,000<1,000discharge overboardNoWill humans be there? If yes, expect conventional wasteEXAMPLE: Sanitary waste waterSanitary waste from livingquartersX bbl/well X bbl/hr/wellchlorinate and dischargeoverboardNoDomestic wastesoap, rinse water 2,000,000 gallons3,500 gal/daydischarged overboardNoSanitary wasteSanitary waste from living quarters1.4 million gallons< 2,500 gal/daydischarged overboardNoIs there a deck? If yes, there will be Deck DrainageDeck Drainagerainwater. Washdown water30,000 barrels 100 bbl/hroverboard dischargeNoWill you conduct well treatment, completion, or workover?Well treatment fluidsN/AWell completion fluids8000 bbl< 100 bbl/hourTreat and dischargeNoWorkover fluidsN/AMiscellaneous discharges. If yes, only fill in those associated with your activity.Desalinization unit dischargeSeawater 200 bbl/day200 bbl/daydischarged to seaNoBlowout prevent fluidEnvironmental safe fluid 10 bbl10 bbl/welldischarged to seaNoBallast waterSeawater 3,000 bbl3,000 bbldischarged to seaNoBilge waterN/AExcess cement at seafloorCement, additives 800 barrels800 barrels/welldischarged at seaNoFire waterSeawater 20,000 bbl/well<100 bbl/hrdischarged at seaNoCooling waterSeawater - non-contactWill you produce hydrocarbons? If yes fill in for produced water.Produced waterN/AWill you be covered by an individual or general NPDES permit ?GENERALNOTE: If you will not have a type of waste, enter NA in the row.TABLE 1. WASTES YOU WILL GENERATE, TREAT AND DOWNHOLE DISPOSE OR DISCHARGETO THE GOMProjectedDownholeDisposalEni US Operating Co. Inc. Page 8

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 619 (OCS-G 32700 & 32704) SECTION G
AIR EMISSIONS INFORMATION

The Air Quality Report was revised for the year 201 1 since the exploration activities were moved for W ell Location “A”, please see attached sheets.

All other information on the Air Quality Report wil l remain the same as approved under Control No. N-9 509, page 11, Air Quality Report and no other impacts or chan ges will be made for Locations “B” to “G”; the emis sions for these locations will remain the same as previously approved.Eni US Operating Co. Inc. Page 9

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION H
OIL SPILLS INFORMATION

(a) Oil Spill Response Planning (2)(i) All the proposed activities and facilities in this Exploration Plan will be covered by Eni’s Oil Spill Response Plan filed by Eni US Operating Co. Inc. – Operator number 02782 in accordance with 30 CFR 254 and approved on March 17, 2009 and most recentl y modified on October 25, 2010.

(a)(2)(ii) SPILL RESPONSE SITES

Primary Response Equipment Location Preplanned Stag ing Location(s) Clean Gulf Associates - Venice, Louisiana Clean G ulf Associates – Galveston, Ingleside, and Houston, Texas, Intracoastal City, Venice, Lake Charles, Leeville, Houma, and Fort Jackson,

Louisiana

(a)(2)(iii) OSRO INFORMATION Eni’s primary equipment provider is Clean Gulf Asso ciates (CGA). The Marine Spill Response Corporatio n’s (MSRC) STARS network will provide closest available personnel, as well as an MSRC supervisor to operat e the equipment.

(a)(2)(iv) WORST-CASE SCENARIO COMPARISON

Category Regional OSRP

WCD EP
WCD

Type of Activity Exploratory Exploratory

Facility Location (Area/Block) MC 546 Walker Ridge 675 & 719

Facility Designation Semi-Submersible Locations A to G

Distance to Nearest Shoreline (miles) 38 193

Volume Storage tanks (total)
Uncontrolled blowout

Total Volume 156,816 5,194

Type of Oil(s) (crude, condensate, diesel) Oil Oil

API Gravity 41.3 ° 32°

Eni has determined that the worst-case scenario fro m the activities proposed in this EP do not superse de the worstcase scenario from our approved Regional OSRP.

Since Eni has the capability to respond to the wors t-case spill scenario included in our Regional OSRP approved on March 17, 2009, and most recently modified on Octob er 25, 2010, since the worst-case scenario determin ed for our EP does not replace the worst-case scenario in our Regional OSRP, I hereby certify that Eni has the ca pability to respond, to the maximum extent practicable, to a wo rst-case discharge, or a substantial threat of such a discharge, resulting from the activities proposed in our EP

. Eni’s Regional OSRP Certification was accepted December 29, 2010.Eni US Operating Co. Inc. Page 10

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) (b) Spill Response Discussion for NEPA Analysis

For the purpose of NEPA and Coastal Zone Management Act analysis, the largest spill volume originating from the proposed activity would be a w ell blowout during drilling operations, estimated t o be 5,194 barrels of crude oil with an API gravity of 3 2°.

Land Segment and Resource Identification Trajectories of a spill and the probability of it i mpacting a land segment have been projected utilizi ng information in the BOEM Oil Spill Risk Analysis Mod el (OSRAM) for the Central and Western Gulf of
Mexico available on the BOEM website.

The results are shown in Figure 1. The BOEM OSRAM i dentifies a 2% probability of impact to the shorelines of Matagorda County, Texas and/or Camero n Parish, Louisiana within 30 days. Matagorda County stretches from Matagorda Bay, across the Col orado River and up to the border of San Bernard Wildlife Refuge (immediately west of the San Bernar d River). The county includes Matagorda Peninsula on the Gulf coast and Matagorda Bay. This area is p rimarily open beach. However, marshland exists along the east side of Matagorda Bay. Several bird rookeries are present around the peninsula. Seagras s is present off of Matagorda Peninsula on the bay side. Cameron Parish includes the east side of Sabine Lake, Sabine National Wildlife Refuge, Calcasieu La ke, Lacassine National Wildlife Refuge (inland) and
Grand Lake. Cameron Parish also includes the area a long the coastline from Sabine Pass to Big Constance Lake in Rockefeller Wildlife Refuge. This region is composed of open public beaches, marshlands and swamps. It serves as a habitat for n umerous birds, finfish and other animals, including several rare, threatened and endangered species.

Response Eni US Operating Co. Inc. will make every effort to respond to the Worst Case Discharge as effectively as practicable. A description of the response equip ment available to contain and recover the Worst Cas e Discharge is shown in Figure 2. Using the estimated chemical and physical characteristics of crude oil , an ADIOS weathering model was run on a similar product from the ADIOS oil database. The results indicate 36% or 1,869 barrels of crude oil would be evaporat ed/dispersed within 24 hours, with 3,325 barrels remaining.

Spill Response WR 719 Barrels of Oil

WCD Volume 5,194

Less 36% natural evaporation/dispersion 1,869 Remaining volume 3,325 Oil addressed by aerial dispersants 7,540 Oil addressed by in-situ burning 166

Figure 2 outlines equipment, personnel, materials and suppor t vessels as well as temporary storage equipment available to respond to a spill of 5,194 barrels. The list estimates individual times needed for procurement, load out, travel time to the site and deployment. Figure 2 also indicates how operations will be supported.Eni US Operating Co. Inc. Page 11

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) If aerial dispersants are utilized, 8 sorties (9,60 0 gallons) from two of the DC-3 aircrafts and 4 sor ties (8,000 gallons) from the Basler aircraft should dis perse approximately 7,540 barrels of product. If th e conditions are favorable for in-situ burning, the p roper approvals have been obtained and the proper planning is in place, in-situ burning of oil may be attempted. Using estimates based on the Deepwater Horizon spill of 2010, up to 5% or 166 barrels of t he total daily Worst Case Discharge volume could be burned. Slick containment boom would be immediately called out and on-scene as soon as possible. Offshore response strategies may include attempting to skim utilizing the HOSS Barge and three Fast Response Units (FRUs), with a total derated skimmin g capacity of 54,310 barrels. Temporary storage associated with skimming equipment equals 4,500 bar rels. If additional storage is needed, a 47,000 bar rel storage barge and a 20,000 barrel storage barge may be mobilized and centrally located to provide temporary storage allowing the skimmers to stay in the area of operations as much as possible. Safety is first priority. Air monitoring will be accomplished and operations deemed safe prior to any containment/skimming attempts.

If the spill went unabated, shoreline impact in Mat agorda County, Texas and/or Cameron Parish, Louisiana would depend upon existing environmental conditions. Shoreline protection would include the
use of CGA’s near shore and shallow water skimmers with a totaled derated skimming capacity of 18,253 barrels. Temporary storage associated with skimming equipment equals 1,317 barrels. If additional storage is needed, a 20,000 barrel storage barge ma y be mobilized and centrally located to provide temporary storage allowing the skimmers to stay in the area of operations as much as possible. Onshore response may include the deployment of shoreline bo om on beach areas, or protection and sorbent boom on vegetated areas. A Letter of Intent from Oil Mop will ensure access to over 30,000 feet of 18” shoreline protection boom. Figure 2 (below) outlines individual times needed for procur ement, load out, travel time to the site and deployment. Strategies would be based upon surveillance and real time trajectories that depict areas of potential impact given actual sea and weather conditions. The State of Louisiana Initial Oil Spill Response Plan for Camer on Parish and Unified Command would be consulted to ensure that environmental and special economic r esources would be correctly identified and prioriti zed to ensure optimal protection. Shoreline protection strategies depict the protection response modes applicable for oil spill clean-up operations. The S tate of Louisiana Initial Oil Spill Response Plan provides detailed shoreline protection strategies f or this area, and it describes necessary action to keep the oil spill from entering Louisiana’s coastal wetland s, based on the assumption that removal of the rele ased oil will be much easier and less damaging to fragil e coastal ecosystems if done in the open waters of the Gulf of Mexico. The One-Gulf Plan (Area Contingency Plan) and Unified Command would be consulted to ensure that environmental and special economic r esources would be correctly identified and prioriti zed to ensure optimal protection. Shoreline protection strategies 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 i n areas of environmental concern.

Supervisory personnel have the option to modify the deployment and operation of equipment allowing a more effective response to site-specific circumstan ces. Eni US Operating Co. Inc.’s contract Spill Management Team holds a copy of the One-Gulf Plan a nd the State of Louisiana Initial Oil Spill Response Plan.Eni US Operating Co. Inc. Page 12

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) 

### Initial Response Considerations Actual actions taken during an oil spill response w ill be based on many factors to include but not
be limited to:

• Weather • Equipment and materials availability
• Ocean currents and tides • Location of the spill • Product spilled • Amount spilled
• Environmental risk assessments • Trajectory and product analysis • Well status, i.e., shut in or continual release

Eni US Operating Co. Inc. will take action to provi de a safe, aggressive response to contain and recov er as much of the spilled oil as quickly as it is safe to do so. In an effort to protect the environment, response actions will be designed to provide an “in-depth” p rotection strategy meant to recover as much oil as possible as far from environmentally sensitive area s as possible. Safety will take precedence over all other considerations during these operations.

Upon notification of a spill, the following actions will be taken:
• Information will be confirmed • An assessment will be made and initial objectives set • OSROs and appropriate agencies will be notified • ICS 201, Initial Report Form completed • Initial Safety plan will be written and published
• Unified Command will be established

o Overall safety plan developed to reflect the operat ional situation and coordinated objectives

o Areas of responsibility established for Source Cont rol and each surface operational site

o On-site command and control established



### Offshore Response Actions

Equipment Deployment
Surveillance • Surveillance Aircraft: within two hours of QI not ification, or at first light • Provide trained observer to provide on site statu s reports • Provide command and control platform at the site if needed • Continual surveillance of oil movement by remote sensing systems, aerial photography and visual
confirmation • Continual monitoring of vessel assets using vesse l monitoring systems

Dispersant application assets • Put ASI on standby • With the FOSC, conduct analysis to determine appr opriateness of dispersant application • Gain FOSC approval for use of dispersants on the surface • Deploy aircraft in accordance with a plan develop ed for the actual situation • Coordinate movement of dispersants, aircraft, and support equipment and personnel • Confirm dispersant availability for current and l ong range operations • Start ordering dispersant stocks required for exp ected operationsEni US Operating Co. Inc. Page 13

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) Containment boom • Call out early and expedite deployment to be on s cene ASAP • Ensure boom handling and mooring equipment is dep loyed with boom • Provide continuing reports to vessels to expedite their arrival at sites that will provide for their
most effective containment • Use Vessels of Opportunity (VOO) to deploy and ma intain boom

Dedicated off-shore skimming systems
General • Deployed to the highest concentration of oil • Assets deployed at safe distance from aerial disp ersant and in-situ burn operations

CGA HOSS Barge
• Use in areas with heaviest oil concentrations • Consider for use in areas of known debris (seawee d, and other floating materials)

CGA FRUs
• To the area of the thickest oil
• Use as far off-shore as allowed

Storage Vessels • Establish availability of CGA contracted assets • Early call out (to allow for tug boat acquisition and deployment speeds) • Phase mobilization to allow storage vessels to ar rive at the same time as skimming
systems • Position as closely as possible to skimming asset s to minimize offloading time

Vessels of Opportunity (VOO) • Use Eni US Operating Co. Inc.’s contracted resour ces as applicable • Industry vessels are usually best for deployment of Vessel of Opportunity Skimming Systems (VOSS) • Acquire additional resources as needed • Consider use of local assets, i.e. fishing and pl easure craft • Expect mission specific and safety training to be required • Plan with the US Coast Guard for vessel inspectio ns

In-situ Burn assets • Determine appropriateness of in-situ burn operati on in coordination with the FOSC and affected

SOSC • Determine availability of fire boom and selected ignition systems • Start ordering fire boom stocks required for expe cted operations • Contact boom manufacturer to provide training if required • Determine assets to perform on water operation • Build operations into safety plan • Conduct operations in accordance with an approved plan

Near Shore Response Actions Timing • Put near shore assets on standby and deployment i n accordance with planning based on the actual situation, actual trajectories and oil budgets • VOO identification and training in advance of spi ll nearing shoreline if possibleEni US Operating Co. Inc. Page 14

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) • Outfitting of VOOs for specific missions • Deployment of assets based on actual movement of oil

Considerations • Water depth, vessel draft • Shoreline gradient
• State of the oil
• Use of VOOs
• Distance of surf zone from shoreline

Equipment Deployment
Surveillance • Provide trained observer to direct skimming opera tions • Continual surveillance of oil movement by remote sensing systems, aerial photography and visual

confirmation • Continual monitoring of vessel assets

Dispersant Use • Generally will not be approved within 3 miles of shore or with less than 10 meters of water depth • Approval would be at Regional Response Team level (Region 6)

Vessel Deployment Dedicated Near Shore skimming systems

• FRVs • Egmopol and Marco SWS • Operate with aerial spotter directing systems to observed oil slicks

VOO • Use Eni US Operating Co. Inc.’s contracted resour ces as applicable • Industry vessel are usually best for deployment o f Vessel of Opportunity Skimming Systems (VOSS) • Acquire additional resources as needed • Consider use of local assets, i.e. fishing and pl easure craft • Expect mission specific and safety training to be required • Plan with the US Coast Guard for vessel inspectio ns • Operate with aerial spotter directing systems to oil patches



### Shoreline Protection Operations

Response Planning Considerations • Environmental risk assessments (ERA) to determine priorities for area protection • Time to acquire personnel and equipment and their availability

• Previous contingency planning contained in the appr opriate Area Contingency Plan, and currently (Feb 2011) for Louisiana, The State of Lo uisiana Initial Oil Spill Response Plan, Deep Water Horizon, dated 2 May 2010 (La. OSRP)



### Actions

Placement of boom

• Position boom in accordance with the ERA based on t he actual situation or the appropriate

ACPEni US Operating Co. Inc. Page 15

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) • Assess timing of booming operations to ensure it is where it needs to be at time of impact.
Consider:

o Trajectories

o Weather forecast

o Oil Impact forecast

o Verified spill movement

o Boom, manpower and vessel (shallow draft) availabil ity

o Near shore boom and support material, (stakes, anch ors, line)

Beach Preparation

Considerations and Actions • Use of a 10 mile go/no go line to determine timin g of beach cleaning • Shoreline Cleanup and Assessment Team Reports and recommendations • Determination of Archeological sites and gaining authority to enter • Monitoring of tide tables and weather to determin e extent of high tides • Pre cleaning of beaches by moving waste above hig h time lines to minimize waste • Staging of equipment and housing of response pers onnel as close to the job site as possible to
maximize on-site work time • Boom tending, repair, replacement and security (u se of local assets may be advantageous)
• Constant awareness of weather and oil movement fo r resource redeployment as necessary • In-situ burn may be considered when marshes have been impacted • Passive clean up of marshes should considered and appropriate stocks of sorbent boom and/or sweep obtained • Earthen berms and shoreline protection boom may b e considered to protect sensitive inland areas

Decanting Strategy Recovered oil and water mixtures will typically sep arate into distinct phases when left in a quiescent state. When separation occurs, the relatively clean water phase can be siphoned or decanted back to th e recovery point with minimal, if any, impact. Decant ing therefore increases the effective on-site oil s torage capacity and equipment operating time. FOSC/SOSC ap proval will be requested prior to decanting operations. This practice is routinely used for oil spill recovery.

CGA Equipment Limitations The capability for any spill response equipment, wh ether a dedicated or portable system, to operate in differing weather conditions will be directly in re lation to the capabilities of the vessel the system in placed on. Most importantly, however, the decision to operate will be based on the judgment of the Unified Command and/or the Captain of the vessel, w ho will ultimately have the final say in terminatin g operations. Skimming equipment listed below may hav e operational limits which exceed those safety thresholds. As was seen in the Deepwater Horizon (D WH) oil spill response, vessel skimming operations
ceased when seas reached 5-6 feet and vessels were often recalled to port when those conditions were exceeded. Systems below are some of the most up-to- date systems available and were employed during the DWH spill.Eni US Operating Co. Inc. Page 16

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704)

Boom 3 foot seas, 20 knot winds Dispersants Winds more than 25 knots Visibility less than 3 nautical

miles Ceiling less than 1,000 feet.

FRU 8 foot seas HOSS Barge/OSRB 8 foot seas Koseq Arms 8 foot seas

OSRV OSRV 4 foot seas



### Environmental Conditions in the GOM Prevailing winds, waves and currents along the Texa s coast are from the southeast and northeast quadrants. Ten to 20 foot waves may occur during hu rricanes. The combined effect of the winds, surface currents, and waves refracting shoreward produce th e prevailing westerly longshore currents. Tides are semi-diurnal and diurnal, and range in height from less than 1 foot to 2.5 feet. The direction, force, and
duration of the wind has a considerable effect on t he tides and currents. Fifteen foot tides may be expected during severe hurricanes and very low tide s may accompany strong northerlies of long duration

. Surface water temperature averages slightly less th an 90° F and ranges between 80 and 100° F during th e late summer. During the winter the average is sligh tly less than 60° F and the range is between 35 and 80°

F.

Louisiana is situated between the easterly and west erly wind belts, and therefore, experiences westerl y winds during the winter and easterly winds in the s ummer. Average wind speed is generally 14-15 mph along the coast. Wave heights average 4 and 5 feet. However, during hurricane season, Louisiana has recorded wave heights ranging from 40 to 50 feet hi gh and winds reaching speeds of 100 mph. Because much of southern Louisiana lies below sea level, fl ooding is prominent. Surface water temperature rang es between 70 and 80°F during the summer months. Durin g the winter, the average temperature will range
from 50 and 60°F.

The Atlantic and Gulf of Mexico hurricane season is officially from 1 June to 30 November. 97% of all tropical activity occurs within this window. The At lantic basin shows a very peaked season from August through October, with 78% of the tropical storm day s, 87% of the minor (Saffir-Simpson Scale categorie s 1 and 2) hurricane days, and 96% of the major (Saff ir-Simpson categories 3, 4 and 5) hurricane days occurring then. Maximum activity is in early to mid September. Once in a few years there may be a hurricane occurring "out of season" - primarily in May or December. Globally, September is the most active month and May is the least active month.Eni US Operating Co. Inc. Page 17

Revised Exploration Plan (Control No. R-5089 DECEM BER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704)Eni US Operating Co. Inc.Page18Revised Exploration Plan (Control No. R-5089 DECEMBER 1, 2010Walker Ridge 675 & 719 (OCS-G 32700 & 32704)Eni US Operating Co. Inc.Page19Revised Exploration Plan (Control No. R-5089 DECEMBER 1, 2010Walker Ridge 675 & 719 (OCS-G 32700 & 32704)Eni US Operating Co. Inc.Page20Revised Exploration Plan (Control No. R-5089 DECEMBER 1, 2010Walker Ridge 675 & 719 (OCS-G 32700 & 32704)Eni US Operating Co. Inc.Page21Revised Exploration Plan (Control No. R-5089 DECEMBER 1, 2010Walker Ridge 675 & 719 (OCS-G 32700 & 32704)Eni US Operating Co. Inc. Page 22

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION I
ENVIRONMENTAL MONITORING INFORMATION

The information for this section was discussed unde r an approved Initial Exploration Plan, Control No. N-9509, page 14, Environmental Monitoring Information and w ill remain the same, no changes or impacts.Eni US Operating Co. Inc. Page 23

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION J
LEASE STIPULATIONS INFORMATION

The information for this section was discussed unde r an approved Initial Exploration Plan, Control No. N-9509, page 15, Lease Stipulation Information and will rem ain the same, no changes.Eni US Operating Co. Inc. Page 

### 24

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION K
ENVIRONMENTAL MITIGATION MEASURES INFORMATION

(a) Mitigation Measures Taken to Minimize Impact to Marine and Coastal Environment Eni does not propose to use any measures beyond tho se required by the regulations in this part to minimize or mitigate environmental impacts from our proposed activities.

(b) Incidental Takes Eni US Operating Co. Inc. will adhere to the requir ements as set forth in the following documents, as applicable, to avoid or minimize impacts to any of the species listed in the ESA as a result of the operations conducted herein:

• NTL 2007-G04, “Vessel Strike Avoidance and Injured/ Dead Protected Species Reporting

• NTL 2007-G03, “Marine Trash and Debris Awareness an d Elimination”

• NTL 2007-G02, “Implementation of Seismic Survey Mit igation Measures and Protected Species Observer Program”Eni US Operating Co. Inc. Page 25

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) APPENDIX L
SUPPORT VESSELS AND AIRCRAFT INFORMATION

General
The information for this section was discussed unde r an approved Initial Exploration Plan, Control No. N-9509, page 18 and will remain the same, no changes.

Diesel Oil Supply Vessels Size of Fuel Supply
Vessel Capacity of Fuel Supply Vessel Frequency of Fuel Transfers Route Fuel Supply
Vessel Will Take 210 feet 202,280 gals Weekly From the Shorebase in Fourchon, LA, to the rig at
WR619/675

Drilling Fluid/



### Solid and Liquid Waste Transportation

TABLE 2:

WASTES YOU WILL TRANSPORT AND /OR DISPOSE OF ONSHOR E

Vicinity Map A vicinity map was submitted and approved under an Initial Exploration Plan, Control No. N-9509, page 18; no changes.please specify whether the amount reported is a total or per wellProjectedgenerated wasteSolid and Liquid WastestransportationType of Waste Composition Transport MethodName/Location ofFacility Amount Disposal MethodWill drilling occur ? If yes, fill in the muds andcuttings.EXAMPLE: Synthetic-based drilling fluid ormudinternal olefin, esterBelow deck storage tanks on offshoresupport vesselsNewport EnvironmentalServices Inc., Ingleside,TXX bbl/well RecycledOil-based drilling fluid or mudN/ASynthetic-based drilling fluid or mudolefin, esterBelow deck storage tanks on offshore support vesselsNewpark Environmental, Fourchon, LA10,000 bbls RecycledCuttings wetted with Water-based fluidN/ACuttings wetted with Synthetic-based fluidN/ACuttings wetted with oil-based fluidsN/AWill you produce hydrocarbons? If yes fill in for produced sand.Produced sandN/AEXAMPLE: trash and debris (recylables)Plastic, paper, aluminumbarged in a storage binARC, New Iberia, LAX lb/wellRecycledTrash and debris (recyclable materials)Plastic, paper, aluminumPlaced in green bags, taken to shoreand placed in 30 yd roll-off contaners forrecylingARC, New Iberia, LA20 cubic meters per wellRecycledUsed oilOil, Engine components Tote tanksL&L 6,000 gallons RecycledWash waterOil contaminated Tote tanks L&L 500 gallonsRecycledChemical product wastessolvents, cleaning fluids, wax Tote tanks L&L 3,000 gallons RecycledNOTE: If you will not have a type of waste, enterNA in the row.Waste DisposalTABLE 2. WASTES YOU WILL TRANSPORT AND /OR DISPOSEOF ONSHOREWill you have additional wastes that are not permitted for discharge? If yes,fill in the appropriate rows.Eni US Operating Co. Inc. Page 26

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 719 (OCS-G 32700 & 32704) SECTION M
ONSHORE SUPPORT FACILITIES INFORMATION

The information for this section was discussed unde r an approved Initial Exploration Plan, Control No. N-9509, page 19 under Onshore Support Facilities Informatio n and will remain the same, no changes.Eni US Operating Co. Inc. Page 27

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION N COASTAL ZONE MANAGEMENT (CZMA) INFORMATION

Relevant enforceable policies were considered in ce rtifying consistency for Louisiana. A certificate of Coastal Zone Management Consistency for the state o f Louisiana is enclosed.Eni US Operating Co. Inc. Page 28

Revised Exploration Plan (Control No. R-5089) DECE MBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION O ENVIRONMENTAL IMPACT ANALYSIS (EIA)

In accordance with the requirements of 30 CFR 250.2 27 and 250.261 an Environmental Impact Analysis (EI A) was submitted and approved under an Initial Exploration Plan, Control No. N-9509. No additional changes to this

section.Eni US Operating Co. Inc. Page 29

Revised Exploration Plan (Control No. R-5089) DECEMBER 1, 2010 Walker Ridge 675 & 719 (OCS-G 32700 & 32704) SECTION P
ADMINISTRATIVE INFORMATION

(a) Exempted Information Description The proposed bottom-hole locations of the planned w ell have been removed from the public information copy of the EP as well as any discussions of the target objecti ves, geologic or geophysical data, and any interpre ted geology.

(b) Bibliography

Initial Exploration Plan, Control No. N-9509, Appro ved May 2010.