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-05299

Type - Revised Exploration Plan

Lease(s) - OCS-G22367 Block - 736 Keathley Canyon Area

Operator - Chevron U.S.A. Inc.

Wells A2, A3 and A4

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.

Chiquita Hill

Plan Coordinator

Description -

Rig Type -

Subject:

From:

December 8, 2011
PUBLIC INFORMATION

REVISED EXPLORATION PLAN R-5299

CHEVRON U.S.A. INC.

KEATHLEY CANYON BLOCK 736

OCS-G 22367

OFFSHORE LOUISIANA

“MOCCASIN” PROSPECT

RECORD CHANGE LOG

Submission 

Type

Date Received Document Type Page Number

Initial 9/6/2011 Revised Exploration Plan

Section A Plan Contents

Section C Geological and Geophysical 

Information

Section E Biological, Physical and 

Socioeconomic Information

Section G Air Emissions Information

Section H Oil Spills Information

2-8

13-17

19-48

52-57

58-63

Amended 9/30/2011 Amended Exploration Plan

Complete copy of Revised Plan with all 

sections included

1-69

Amended 10/4/2011 LA CZM Certificate 68
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

REVISED EXPLORATION PLAN R-5299

CHEVRON U.S.A. INC.

KEATHLEY CANYON BLOCK 736

OCS-G 22367

OFFSHORE LOUISIANA

“MOCCASIN” PROSPECT

SECTION A PLAN CONTENTS 

SECTION B GENERAL INFORMATION 

SECTION C GEOLOGICAL AND GEOPHYSICAL INFORMATION 

SECTION D HYDROGEN SULFIDE (H2S) INFORMATION

SECTION E BIOLOGICAL, PHYSICAL, AND SOCIOECONOMIC INFORMATION

SECTION F WASTE AND DISCHARGE INFORMATION

SECTION G AIR EMISSIONS INFORMATION

SECTION H OIL SPILLS INFORMATION

SECTION I ENVIRONMENTAL MONITORING INFORMATION

SECTION J LEASE STIPULATIONS INFORMATION

SECTION K ENVIRONMENTAL MITIGATION MEASURES INFORMATION

SECTION L SUPPORT VESSELS AND AIRCRAFT INFORMATION

SECTION M ONSHORE SUPPORT FACILITIES INFORMATION

SECTION N COASTAL ZONE MANAGEMENT ACT (CZMA) INFORMATION

SECTION O ENVIRONMENTAL IMPACT ANALYSIS (EIA) 

SECTION P ADMINISTRATIVE INFORMATION

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Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION A PLAN CONTENTS

(a) PLAN INFORMATION FORM

Included as attachment A-1 at the end of this section is Form MMS-137 “OCS Plan Information Form”.

Previously approved activity:

Well A (OCS-G 22367 001) was spud on March 12, 2010 and suspended on June 9, 2010. A Revised Permit to Drill 

(RPD) was submitted on November 5, 2010 and approved on March 24, 2011. Drilling operations for the OCS-G 

22367 001 well resumed on March 26, 2011. The well was permanently abandoned October 3, 2011. 

All the proposed wells will be drilled using a Subsea BOP.

Proposed Schedule

Proposed Activity Estimated 

Start Date

Estimated 

End Date

Estimated 

No. of Days

Drill, Complete, Test and Abandon Exploratory Well A2 02/01/2012 06/29/2012 150

Drill, Complete, Test and Abandon Exploratory Well A3 06/30/2012 11/26/2012 150

Drill, Complete, Test and Abandon Exploratory Well A4 11/27/2012 04/25/2013 150

(b) LOCATION / BATHYMETRY MAP

Included as attachment A-2 is a bathymetry map at a scale of 1”=2,000’ showing the surface locations for the 

proposed wells.

(c) SAFETY and POLLUTION PREVENTION FEATURES 

Chevron plans to use a drillship to drill the wells proposed in this plan. The drillship is equipped with a Subsea BOP. 

Rig specifications will be provided with the Applications for Permit to Drill. If another rig type is used, any differences 

regarding air emissions, safety, drilling or pollution control equipment will be addressed in a revised Exploration Plan.

In accordance with 30 CFR 250.406, Chevron will ensure that safety features will include well control, pollution 

prevention, welding procedure, and blowout prevention equipment and as further clarified by BOEMRE Notices to 

Lessees and current policy making invoked by the BOEMRE.

The rig will be monitored daily by a Chevron drilling representative and any waste or fuel resulting in pollution of the 

Gulf waters will be reported to the representative in charge for immediate isolation and correction of the problem. 

Any spill will be reported to governmental agencies. Chevron will comply with all BOEMRE Regulations during the 

course of the activities. 

 

The rig is equipped with safety, fire fighting, and lifesaving equipment required to comply with USCG, ABS, SOLAS, 

and IMO code requirements. 

 

Chevron will comply with all pertinent regulations in 30 CFR 250.203, NTL’s, and all federal and state documents to 

ensure that the proposed activities are safe and that there is minimal impact on the environment. Chevron will 

maintain compliance with the EPA NPDES Permit and lease agreement during these proposed activities.

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Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

(d) TABLE of STORAGE TANKS and PRODUCTION VESSELS

Information regarding the storage tanks that will be used to conduct the proposed activities in this plan that will store 

oil, as defined at 30 CFR 254.6, is provided in the table below. Only those tanks with a capacity of 25 barrels or 

more are included.

Storage Tank Facility Type Tank Capacity

(bbls)

Tanks

(no.)

Total Capacity

(bbls)

Fluid Gravity

(API)

Main Fuel Oil

Drillship

18,000 2 36,000

No. 2 diesel

Diesel Settling 837 2 1,674

Diesel Day 837 2 1,674

Emergency Diesel 100 1 100

Diesel Overflow 823 1 823

Diesel Oil Drain Aft 42 1 42

Engine Oil Storage 182 1 182 26.2

Gear Oil Aft 62 1 62 27

Gear Oil Fwd 176 1 176 27

Hydraulic Oil Aft 84 1 84 31

Hydraulic Oil Fwd 87 1 87 31

(g) ADDITIONAL SAFETY, POLLUTION PREVENTION, AND EARLY SPILL DETECTION MEASURES BEYOND 

THOSE REQUIRED IN 30 CFR 250.

In addition to pollution prevention measures utilized by Chevron, the drill ship has a comprehensive, proactive plan to 

address emergency situations that could result in an unanticipated oil/chemical release. The “Shipboard Oil Pollution 

Emergency Plan” has specific checklists and procedures to address accidental releases due to fuel/oil transfer, tank 

overflow, hull leakage, fire, explosion, collision and grounding. This plan is reviewed annually and oil pollution 

prevention drills are conducted as specified by MARPOL regulations. There is a fully stocked environmental 

equipment locker located on the main deck, forward of the Moon-pool and numerous spill kits located throughout the 

main deck. The decks of the drillship are fully contained, a comprehensive scupper management plan in place, and 

any spills on the deck would be immediately cleaned up using absorbents or permitted solvents.

ATTACHMENTS TO SECTION A

• A-1 - Form MMS-137 “OCS Plan Information Form” (Public Information Copy)

• A-2 - Bathymetry/Location Plat, Scale: 1”=2,000’

3
ATTACHMENT A-1 PUBLIC INFORMATION

U.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) Development Operations Coordination Document (DOCD)

Company Name: Chevron U.S.A. Inc. MMS Operator Number: 00078

Address: 1500 Louisiana Street Contact Person: Philip A. Von Dullen III 

 Houston, TX 77002 Phone Number: (832) 854-3644 

E-Mail Address: pvondullen@chevron.com 

Lease(s):

OCS-G 22367 

Area:

Keathley Canyon 

Block(s)

736 

Project Name (If Applicable):

Moccasin

Objective(s) X Oil X Gas Sulphur Salt Onshore Base: Leeville,LA Distance to closest land (Miles): 216

Description of Proposed Activities (Mark all that Apply)

X Exploration Drilling Development Drilling

X Well completion Installation of production platform

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

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

Installation of sub sea wellheads and/or manifolds Commence production

Installation of lease term pipelines Other (specify and describe)

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

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

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

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

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

Tentative Schedule of Proposed Activities

Proposed Activity Start Date End Date No. of Days

Drill, complete and abandon Exploratory Well A2 02/01/2012 06/29/2012 150

Drill, complete and abandon Exploratory Well A3 06/30/2012 11/26/2012 150

Drill, complete and abandon Exploratory Well A4 11/27/2012 04/25/2013 150

Description of Drilling Rig Description of Production Platform

Jack up X Drill ship Caisson Tension leg platform

Gorilla Jack up Platform rig Well protector Compliant tower

Semi submersible Submersible Fixed platform Guyed tower

DP Semi submersible Other (attach description) Sub sea 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)

MMS Form MMS-137 (August 2003 – Supersedes all previous editions of form MMS-137, which may not be used.)

Page 1 of 2

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ATTACHMENT A-1 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 structure, reference previous name):

KC 736 “A2”

Sub sea Completion

Anchor Radius (if applicable) in feet Yes X No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 22367 PROPRIETARY INFORMATION

Area 

Name KEATHLEY CANYON

Block No. 736

Block line Departures

(in feet)

N / S Departure: 6036 F N L 

E / W Departure: 668 F W L

Lambert X-Y Coordinates X: 1838108

Y: 9529644

Latitude / Longitude Latitude: N 26° 15’ 42.0797” 

Longitude: W 92° 23’ 47.6801” 

Water Depth (Feet) -6789

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

Anchor Name or No. Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

5
ATTACHMENT A-1 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 structure, reference previous name):

KC 736 “A3” 

Sub sea Completion

Anchor Radius (if applicable) in feet Yes X No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 22367 PROPRIETARY INFORMATION

Area 

Name KEATHLEY CANYON

Block No. 736

Block line Departures

(in feet)

N / S Departure: 1242 F N L 

E / W Departure: 7035 F E L 

Lambert X-Y Coordinates X: 1846245

Y: 9534438

Latitude / Longitude Latitude: N 26° 16’ 29.1941”

Longitude: W 92° 22’ 18.0157”

Water Depth (Feet) -6616

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

Anchor Name or No. Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

 

6
ATTACHMENT A-1 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 structure, reference previous name):

KC 736 “A4” 

Sub sea Completion

Anchor Radius (if applicable) in feet Yes X No

Surface Location Bottom-Hole Location (For Wells)

Lease No. OCS-G 22367 PROPRIETARY INFORMATION

Area 

Name KEATHLEY CANYON

Block No. 736

Block line Departures

(in feet)

N / S Departure: 2994 F N L 

E / W Departure: 2660 F E L 

Lambert X-Y Coordinates X: 1850620

Y: 9532686

Latitude / Longitude Latitude: N 26° 16’ 11.6231”

Longitude: W 92° 22’ 48.793”

Water Depth (Feet) -6891

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

Anchor Name or No. Area Block X Coordinate Y Coordinate Length of Anchor 

Chain on Seafloor

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

 

7
X Y Latitude Longitude

KC 736 A2 1838108 9529644 N 26° 15’ 42.0797” W 92° 23’ 47.6801” 6036 FNL 668 FWL

KC 736 A3 1846245 9534438 N 26° 16’ 29.1941” W 92° 22’ 18.0157” 1242 FNL 7035 FEL

KC 736 A4 1850620 9532686 N 26° 16’ 11.6231” W 92° 21’ 30.0337” 2994 FNL 2660 FEL

Well Block Calls (ft)

Designation 

and Block

Cartesian Coordinates 

UTM Zone 15 (ft)

Geographic Coordinates

C1866, NAD 1927

(deg., min., sec.)

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Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION B GENERAL INFORMATION

(a) APPLICATIONS AND PERMITS

In the table below, information is provided on the filing or approval status of the Federal, State, and local application 

approvals or permits that must be obtained to conduct the proposed activities. Only those individual or site-specific 

application approvals that must be obtained are listed.

Application/Permit Issuing Agency Status

NPDES Permit EPA Approved

EEP U.S. Coast Guard To be submitted

APD BOEMRE To be submitted

 

(b) DRILLING FLUIDS

(1) Information on the types (including chemical constituents) and amounts of the drilling fluids planned for use in 

drilling the proposed wells:

Type of Drilling Fluid Estimated Volume of Drilling Fluid to be 

Used per Well

Water-based (seawater, brine, freshwater) 57,203 bbls

Oil-based (diesel, mineral oil) 0 bbls

Synthetic-based (internal olefin, ester) 7,338 bbls

(2) Major Components of Synthetic-based drilling fluid listed above:

Product Name Amount to be Used Reference Number MSDS No.

Lime (Calcium Hydroxide) 900 50-lb bags CAS # 1302-78-9 10046

Calcium Chloride 2500 50-lb bags CAS # 10043-52-4 10109

VG Plus 400 50-lb bags CAS # 68153-30-0 10128

VG Supreme 100 50-lb bags CAS # 14808-60-7 12207

Rheflat 2500 gals CAS # 68855-60-7 12246

Rhethik 1000 gals CAS # 111-46-6 12247

Rheduce 500 gals 12248

Suremul 4500 gals CAS#111-76-2,112-34-5 12243

Surewet 2500 gals CAS # 112-80-1 12245

SafeCarb 2000 50-lb bags CAS # 471-34-1 10337

M-I BAR 5000 tons CAS # 7727-43-7 10617

Synthetic B 8000 bbls 12269

G-Seal 960 bags CAS # 7782-42-5 10391

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Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

(d) OIL CHARACTERISTICS

Characteristic Analytical Methodologies Should be Compatible with:

(1) Gravity (API): 27-29 ASTM D4052

(2) Flash Point (°C): 15 ASTM D93 / IP 34

(3) Pour Point (°C): -9 ASTM D97

(4) Viscosity (Centipoise at 25°C): 22-49 ASTM D445

(5) Wax Content (wt %): 1.0-3.5 Precipitates with 2-butanon/dichloromethane (1 to 1 

volume) at -10 °C

(6) Asphaltene Content (wt %): 5-11 IP-Method 143/84

(7) Resin Content (wt %): 5-8 Jokuty et al. (1996)

(8) Boiling point distribution including, for each 

fraction, the percent volume or weight and the boiling 

point range in degrees C

BOILING POINT (SIMDIS) YIELDS, VOL % 

Lt Gasoline (55-175 oF) 2.7 

Lt Naphtha (175-300 oF) 8.3 

Hvy Naptha (300-400 oF) 8.3 

Kerosene (400-500 oF) 9.2 

Atm Gas Oil (500-650 oF) 14.2 

Lt Vac Gas Oil (650-800 oF) 13.5 

Hvy Vac Gas Oil (800-1050 oF) 18.7 

Vac Resid (1050-FBP oF) 24.9 

ASTM D2892 (TBP distillation), or ASTM D2887/5307

(9) Sulphur (wt %): 2.0 ASTM D4294

Oil from one well

Area/Block: Keathley Canyon 872

MMS Platform ID:

API Well No: 

Completion perforation interval: 26,967 – 28,091’

MMS reservoir name: OCS-G 25823 #1

Sample date: 11/18/2008, 1/13/2009

Sample No. (if more than one): N/A

(e) NEW OR UNUSUAL TECHNOLOGY

No new or unusual technology will be used to carry out the activities proposed in this plan.

(f) BONDING STATEMENT

The bond requirements for the activities and facilities proposed in this EP are satisfied by an area-wide bond, 

furnished and maintained according to 30 CFR part 256, subpart I; NTL No. 2000-G16, “Guidelines for General 

Lease Surety Bonds;” and a current BOEMRE-approved deferment from providing additional security under 30 CFR 

256.53(d) and National NTL No. 2003-N06, “Supplemental Bond Procedures. If, any point, Chevron no longer 

qualifies for a supplemental bonding deferment, Chevron will either provide the required additional security or a third 

party guarantee within 60 days after such disqualification. 

(g) OIL SPILL FINANCIAL RESPONSIBILITY (OSFR)

Chevron U.S.A. Inc., BOEMRE company number 00078, has demonstrated oil spill financial responsibility for the 

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

Responsibility for Covered Facilities.”

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Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

(h) DEEPWATER WELL CONTROL STATEMENT

Chevron U.S.A. Inc., BOEMRE company number 00078, has the financial capability to drill a relief well and conduct 

other emergency well control operations.

(j) BLOWOUT SCENARIO

The Worst Case Discharge Scenario initial flow rate is calculated at 51,650 barrels of oil per day (bopd) by systems 

analysis. The well selected as the Worst Case Discharge case is the A well. In order to evaluate all of the sands that 

would be penetrated in a consistent manner; a constant pressure boundary around the well was applied for each 

sand. 

With all of these assumptions, the flow rate is expected to stabilize to approximately 45,317 bopd during the time 

period required to drill the relief well. Chevron estimates that it would take 131 days to mobilize a rig, drill relief well, 

intersect that blowout well and conduct a kill operation. During this time the Total Potential Spill Volume is estimated 

at 5,989,648 bbls. 

Discussion of Potential for Well to Bridge Over:

Mechanical earth models and pore pressure analysis predict that sandface collapse could be expected to occur in an 

open hole environment under current field pressure conditions in the case of an uncontrolled flow. While Chevron 

considers hole collapse highly likely under the current pressure conditions, based on BOEMRE guidance, we have 

not considered the impact of hole collapse on the Worst Case Discharge Rate calculations.

Relief Well 

Chevron has two other Enterprise Class drillships under contract that could drill the relief well, if needed. These 

drillships do not have any equipment constraints with respect to drilling a relief well for the Moccasin prospect. The 

11-7/8” casing point is selected as the intervention point for the relief well. Chevron estimates that it would take 131 

days to mobilize a rig, drill relief well, intersect that blowout well and conduct a kill operation. This estimate includes 

NPT time and a 30% contingency factor. 

There are no nearby platforms or other infrastructure nearby that would hamper relief well operations. Site surveys 

have been conducted near the current drilling location to identify surface hazards that might impact the selection of a 

relief well location. Two locations have been selected for relief well within a 2,500’ radius – one on the west side and 

one on the south side. Selection of the actual location would be constrained by typical parameters such as planned 

inclination, benign water-bottom and salt entry/exit points, wind and current direction and subsurface hazard 

avoidance. Directional plans for the relief wells are simple build and hold with less than 30 degrees hole angles. 

Casing design for the relief well will be similar to that proposed for the Moccasin well.

Other

Blowout Contingency Planning

In order for Chevron to address its ability to prevent blowouts, reduce the likelihood of blowouts, and conduct 

effective/early intervention in the event of a blowout, Chevron has developed standards for well control, personnel 

safety, and emergency response plans. Chevron has also entered into agreements with industry Subject Matter 

Experts (SME).

At all times from planning through execution, Chevron takes the necessary steps to maintain primary well control to 

prevent the occurrence of blowouts as outlined in the Chevron Well Control Guide.

The drilling team works in conjunction with the geological and geophysical operations team and the Major Capital 

Project team to use their knowledge and good judgment to create best possible well plans and program for any 

particular prospect. All relevant geological information is used to understand the risks and uncertainties that are 

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Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

unique to the location. Appropriate plans are then generated to eliminate or mitigate the identified risks. Special 

equipment for contingency plans is sourced and qualified personnel are identified for conducting the various tasks. 

Prior to the execution phase, all the well control equipment on the rig undergoes a rigorous inspection and

acceptance process/procedure by the Chevron Global Well Intervention group.

To reduce the likelihood of a blowout, appropriate offset information is used to generate pore pressure models that 

predict localized area pore pressure. Maximum Anticipated Surface Pressure (MASP) is calculated to ensure that the 

working pressure of the BOP equipment is not exceeded at any time during well construction. Pressure While Drilling 

(PWD) and Log While Drilling (LWD) data, such as gamma ray, resistivity, sonic, are used during the drilling 

operation to monitor real time pore pressure variances. 

Adjustments can then be made to the mud system to maintain the appropriate overbalance on the pore pressure. 

Mud tank volumes and trip tank volumes are constantly monitored while drilling for early detection of changes in 

anticipated trends. Routine maintenance and testing of blowout prevention equipment ensures the equipment is in 

good working condition during operations. Data sheets and critical wellbore information which are needed in well 

control situations are maintained at the well site.

There will be two (2) barriers available during all normal well activities, operations, suspensions, and abandonments 

to prevent uncontrolled flow from the wellbore to the environment. Prior to removing the Blowout Preventer (BOP) 

from a well which has hydrocarbons, there will be two mechanical barriers in place.

Preliminary plans are developed for potential relief well locations(s) during the planning phase for the primary well(s). 

These preliminary plans can be used to develop detailed relief well drilling plans as needed in a timely manner. Two 

relief well locations have been identified for the primary well location.

In addition to Chevron’s contracted resources to assist in the event of a blowout, Chevron is a founding member of 

the Marine Well Containment Company (“MWCC”), currently has access to MWCC’s Interim Containment Response 

System (“ICRS”), and will have full access to MWCC’s Expanded Containment Response System when it is 

available. These resources, along with Chevron’s own well containment and emergency response planning, give 

Chevron a high probability of regaining control of a blown out well.

Chevron maintains the “Chevron Interim Well Containment Plan (0128-OFGN-RGL-PLN-DGM-0000-00001)” which 

guides Chevron’s procedures and plans for well containment until the expanded Marine Well Containment System is 

in place. Additional details for each component of well containment planning can be found in the Chevron Interim 

Well Containment Plan (“IWCP”), which is available upon request.

Supplemental Worst Case Discharge Information to comply with NTL No. 2010-N06 was included and 

approved in Plan R-5096. 

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Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION C GEOLOGICAL AND GEOPHYSICAL INFORMATION 

(a) GEOLOGICAL DESCRIPTION

Proprietary Information

(b) STRUCTURE CONTOUR MAPS

Proprietary Information

(c) INTERPRETED 2-D AND/OR 3-D SEISMIC LINES

Proprietary Information

 

(d) GEOLOGICAL STRUCTURE CROSS-SECTION

Proprietary Information

 

(e) SHALLOW HAZARDS REPORT

Based on a review of CGG Veritas proprietary exploration 3-D seismic data, a Geologic and Stratigraphic 

Assessment over Keathley Canyon Blocks 692, 693, 735, 736, and 780 was prepared by Geoscience Earth & Marine 

Services, Inc. ®, (GEMS) for Chevron U.S.A. Inc. (Chevron) in April 2009. This proprietary report was submitted with 

the initial plan, N-9380.

(f) SHALLOW HAZARDS ASSESSMENT

A site specific shallow hazard clearance letters were prepared complying with Notice to Lessees (NTL’s), 2008-G05, 

and 2009-G40. NTL 2008-G06 is also pertinent with respect to pre- and post-spud ROV visual inspection surveys. 

The site specific clearance letters are based on findings provided within the main body of the geohazards report for 

KC 692, 693, 735, 736, and 780 (GEMS Report No. 0109-1600; GEMS, 2009). The site clearance letters 

supplement the above report with details pertaining directly to the proposed drill locations, A2, A3, and A4. Two hard 

copies and one digital copy of the proprietary Site Clearance Letters were submitted as an enclosure with the initial 

submittal of the confidential copy of revised plan R-5299. 

A non-proprietary summary of the site specific assessments from the GEMS reports for the proposed locations follow

below:

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Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

KC 736 “A2”

Man-Made Features

The KC 736 #1 well was drilled by Chevron in 2010 in the southern portion of KC 736, approximately 11,275 ft 

southeast of the proposed well location. There are no existing pipelines, cables, or platforms within KC 736 or in the 

immediate surrounding blocks

Wellsite Conditions

The surface location is clear of any constraining conditions within a 2,000-radius circle from the proposed wellsite.

Water Depth, Slope, and Seafloor Sediments. Seafloor conditions are favorable for exploration drilling at the 

proposed wellsite location. The water depth at the proposed surface location is approximately -6,789 ft. The 

Proposed Wellsite KC 736-A2 lies along an expansive shallow salt ridge. The seafloor in this area is irregular as a 

result of the numerous fault scarps and the deformation of the shallow overburden by the underlying salt. Several of 

these fault scarps form a fault-bounded low, or graben, that trends generally northwest-southeast at the proposed 

location. The seafloor at the proposed wellsite, however, is generally smooth, dipping to the southeast at about 1.5°. 

The near-surface sediments are expected to be normally consolidated clays forming a drape over the area.

Deepwater Benthic Communities. There is no indication of fluids or gas venting from nearby faults at the seabed. 

Features or areas that could support high-density deepwater benthic communities are not located within 2,000 ft of 

the proposed location; however, scattered deepwater corals were noted in the ROV data near the KC 736-A2 survey 

location. These “branch-like” corals exist on soft substrate and are not considered to be high-density benthic 

communities that are generally associated with hardgrounds. The Seafloor Amplitude Rendering shows normal or 

ambient amplitudes along the seabed at, and near, the proposed wellsite. 

Stratigraphy. The seafloor and near-surface sediments at the Proposed Wellsite KC 736-A2 are expected to be 

hemipelagic and pelagic clays and silty clays. In general, the sediments between the seafloor and 480 ft bml (-

7,259 ft bsl, below sea level) consist of hemipelagic clays and clay-rich turbidite deposits interlayered in places with 

thin debris flow deposits. Thin sand layers are possible within bedded turbidites and mass-transport deposits 

between 480 ft bml (-7,269 ft bsl) and 968 ft bml (-7,757 ft bsl). The stratigraphic unit below 968 ft bml (7,757 ft bsl) 

to the Top of Salt at about 1,227 ft bml (-8,016 ft bsl) is likely composed primarily of clay-prone mass-transport or 

debris flow deposits. 

Faults. No seafloor faults are expected to be penetrated by the Proposed Wellsite KC 736-A2; however, there are 

several faults near the proposed surface location. The closest seafloor fault to the proposed wellsite is approximately 

777 ft to the west-southwest. The fault trends northwest-southeast and is downthrown to the east-northeast, toward 

the proposed location.

No other distinct faults were mapped at the Proposed Wellsite KC 736-A2; however, the shallow stratigraphic unit 

above the Top of Salt is likely to be highly fractured as a result of the past motion of the underlying shallow salt 

structure. Other faults are likely to exist that are beyond the resolution of the data.

Shallow Gas and Shallow Water Flow. Significant shallow gas is not expected at this wellsite within the upper 

1,227 ft of sediment. The potential for shallow water flow at this well location is considered negligible.

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 736-A2 ranges from 

negligible to low. The well path will not penetrate any high-amplitude events between the seafloor and the Top of 

Salt (1,227 ft bml). A low potential for encountering shallow gas exists from 480 ft bml to the Top of Salt (1,227 ft 

bml). An increase in amplitude character in places may indicate an increase in minor amounts of solution gas within 

possible thin sand layers within these intervals. There is a negligible potential for encountering accumulations of 

shallow gas from the remaining sequence at the proposed wellsite.

Water Flow. There is a negligible potential for shallow water flow within the sedimentary section from the 

seafloor to the Top of Salt (1,227 ft bml). Any thin sand or silty-sand layers encountered are not expected to be 

overpressured. Additionally, the potential for an overpressured environment is considerably reduced by faulting and 

the thin overburden above the shallow salt.

Closing

The Proposed Wellsite KC 736-A2 in Keathley Canyon Block 736 appears suitable for exploration drilling operations. 

The potential for encountering thin sand layers increases between 480 ft and 968 ft bml, but we do not anticipate any 

significant overpressures associated with this interval.

14
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

KC 736 “A3”

Man-Made Features

The KC 736 #1 well was drilled by Chevron in 2010 in the southern portion of KC 736, approximately 14,115 ft southsouthwest of the proposed well location. There are no existing pipelines, cables, or platforms within KC 736 or in the 

immediate surrounding blocks (BOEMRE, 2011a).

Wellsite Conditions

The surface location is clear of any constraining conditions within a 2,000-radius circle from the proposed wellsite.

Water Depth, Slope, and Seafloor Sediments. Seafloor conditions are favorable for exploration drilling at the 

proposed wellsite location. The water depth at the proposed surface location is approximately -6,616 ft. The 

Proposed Wellsite KC 736-A3 lies along an expansive shallow salt ridge. The seafloor in this area is irregular as a 

result of the numerous fault scarps and the deformation of the shallow overburden by the underlying salt. The 

seafloor at the proposed wellsite is generally smooth, dipping to the northeast at about 10.9°; however, video 

captured from the ROV investigation shows a smooth and gradually dipping seafloor. The near-surface sediments 

are expected to be normally consolidated clays forming a drape over the area.

Deepwater Benthic Communities. There is no indication of fluids or gas venting from nearby faults at the seabed. 

Features or areas that could support high-density deepwater benthic communities are not located within 2,000 ft of 

the proposed location; however, scattered deepwater corals were noted in the ROV data near the KC 736-A3 survey 

location. These “branch-like” corals exist on soft substrate and are not considered to be high-density benthic 

communities that are generally associated with hardgrounds. The Seafloor Amplitude Rendering shows normal or 

ambient amplitudes along the seabed at, and near, the proposed wellsite.

Stratigraphy. The seafloor and near-surface sediments at the Proposed Wellsite KC 736-A3 are expected to be 

hemipelagic and pelagic clays and silty clays. In general, the sediments between the seafloor and the possible Top 

of Salt (1,157 ft bml or -7,773 ft bsl, below sea level) consist of hemipelagic clays and clay-rich turbidite deposits 

interlayered in places with thin debris flow deposits. The sediments within the upper 1,157 ft bml (-7,773 ft bsl) likely 

consist primarily of clays and silts; however, thin sand seams may be interspersed within the stratigraphic sequence 

below 215 ft bml (-6,831 ft bsl).

Faults. Several seafloor faults exist near the proposed location. A vertical borehole will intersect a seafloor fault at 

approximately 242 ft bml (-6,858 ft bsl). The fault trends northwest to southeast and is downthrown to the northeast. 

Any further movement along this fault will likely be slow, analogous to a soil creep.

No other seafloor or buried faults are expected to be penetrated; however, the stratigraphic unit above the Top of Salt 

is likely to be highly fractured as a result of the motion of the shallow salt structure. Other faults are likely to exist that 

are beyond the resolution of the data.

Shallow Gas and Shallow Water Flow. Significant shallow gas is not expected at this wellsite within the upper 

1,157 ft of sediment. The potential for shallow water flow at this well location is considered negligible.

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 736-A3 ranges from 

negligible to low. The well path will not penetrate any high-amplitude events between the seafloor and the possible 

Top of Salt (1,157 ft bml). A low potential for encountering shallow gas exists from 215 ft bml to the possible Top of 

Salt (1,157 ft bml). An increase in amplitude character in places may indicate an increase in minor amounts of 

solution gas within possible thin sand layers within this interval. 

Water Flow. There is a negligible potential for shallow water flow within the sedimentary section from the 

seafloor to the possible Top of Salt (1,157 ft bml). Any thin sand or silty-sand layers encountered are not expected to 

be overpressured. Additionally, the potential for an overpressured environment is considerably reduced by faulting 

and the thin overburden above the shallow salt.

Closing

The Proposed Wellsite KC 736-A3 in Keathley Canyon Block 736 appears suitable for exploration drilling operations. 

Thin sands may be encountered between 215 ft and 1,157 ft bml, but we do not anticipate any significant 

overpressures associated with this interval.

15
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

KC 736 “A4”

Man-Made Features

The KC 736 #1 well was drilled by Chevron in 2010 in the southern portion of KC 736, approximately 2.3 miles 

southwest of the proposed well location. Drilling has been suspended on the KC 736 #1 well. There are no existing 

pipelines, cables, or platforms within KC 736 or in the immediate surrounding blocks (BOEMRE, 2011b).

Wellsite Conditions

The surface location is clear of any constraining conditions within a 2,000-radius from the proposed wellsite.

Water Depth, Slope, and Seafloor Sediments. Seafloor conditions are favorable for exploration drilling at the 

proposed wellsite location. The water depth at the proposed surface location is approximately -6,891 ft. The 

Proposed Wellsite KC 736-A4 lies along an expansive shallow salt ridge. The seafloor to the west of the proposed 

location is irregular as a result of numerous fault scarps, seafloor failures, and the deformation of the shallow 

overburden by the underlying salt. The seafloor at the proposed wellsite is generally smooth, and dips to the 

northeast at about 10.8°. The near-surface sediments are expected to be normally consolidated clays forming a 

drape over the area.

Deepwater Benthic Communities. There is no indication of fluids or gas venting from nearby faults at the seabed. 

Features or areas that could support high-density deepwater benthic communities are not located within 2,000 ft of 

the proposed location. The Seafloor Amplitude Rendering shows normal or ambient amplitudes along the seabed at, 

and near, the proposed wellsite. 

Stratigraphy. The seafloor and near-surface sediments at the Proposed Wellsite KC 736-A4 are expected to be 

hemipelagic and pelagic clays and silty clays. In general, the sediments between the seafloor and Horizon 10 (486 ft 

bml) consist of hemipelagic clays and clay-rich turbidite deposits interlayered in places with thin debris flow deposits. 

Thin sand layers are possible within bedded turbidites and mass-transport deposits between Horizon 10 (486 ft bml) 

and Horizon 30 (816 ft bml). The stratigraphic unit below Horizon 30 (816 ft bml) to the Top of Salt at about 1,786 ft 

bml (-8,677 ft bsl) is likely composed of interlayered clay-prone turbidite and mass-transport deposits. 

Faults. Several seafloor faults exist near the proposed location. A vertical borehole will intersect a seafloor fault at 

approximately 1,619 ft bml. The fault trends northwest-southeast and is downthrown to the northeast. Any further 

movement along this fault will likely be slow, analogous to a soil creep.

A vertical borehole will intersect a buried fault at 720 ft bml. This fault generally trends east-west and is downthrown 

to the north. The shallow stratigraphic unit above the Top of Salt is likely to be highly fractured as a result of the past 

motion of the underlying shallow salt structure. Other faults are likely to exist that are beyond the resolution of the 

data.

Shallow Gas and Shallow Water Flow. Significant shallow gas is not expected at this wellsite within the upper 

1,786 ft of sediment. The potential for shallow water flow at this well location is considered negligible (Figure KC736-

A4-2).

Shallow Gas. There is a negligible potential for encountering shallow gas at the Proposed Wellsite KC 736-

A4. The well path will not penetrate any high-amplitude events between the seafloor and the Top of Salt (1,786 ft 

bml). The closest amplitude event is approximately 400 ft north of the proposed location. This event may be 

associated with an increased amount of biogenic gas within possible sand layers between the seafloor and Horizon 

10 (486 ft bml).

Shallow Water Flow. There is a negligible potential for shallow water flow within the sedimentary section 

from the seafloor to the possible Top of Salt (1,786 ft bml). Any thin sand or silty-sand layers encountered are not 

expected to be overpressured. Additionally, the potential for an overpressured environment is considerably reduced 

by faulting and the thin overburden above the shallow salt.

Closing

The Proposed Wellsite KC 736-A4 in Keathley Canyon Block 736 appears suitable for exploration drilling operations. 

16
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

 (g) HIGH RESOLUTION SEISMIC LINES

Proprietary Information

(h) STRATIGRAPHIC COLUMN

Proprietary Information

(i) TIME vs. DEPTH TABLE

Proprietary Information

ATTACHMENTS TO SECTION C (Proprietary Information) 

• C-1- Depth Structure Contour Map, KC Block 736

• C- 2, 4, 6 - Interpreted 3- D Seismic Lines

• C- 3, 5, 7 - Schematic Cross-Sections 

• C-8 - Stratigraphic Column

17
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION D HYDROGEN SULFIDE (H2S) INFORMATION

(a) CONCENTRATION

It is not expected that H2S will be encountered or handled while conducting the activities proposed in this plan.

(b) CLASSIFICATION

Pursuant to 30 CFR 250.490(c), Chevron requests the Regional Supervisor to make a determination of the area’s 

classification of the probability of encountering H2S during operations. No H2S has been produced or encountered in 

the closest wells to the area, KC 736 #1 and the KC 872 #1, which have drilled the same stratigraphic interval. 

Drilling in the surrounding area and correlation of geological and seismic data with equivalent stratigraphic units has 

confirmed an absence of H2S.

The Regional Supervisor has classified the area as H2S absent with the approval of the initial EP. There is no reason 

to request a change in this classification based on the drilling of the wells to date.

(c) H2S CONTINGENCY PLAN

Should the Regional Supervisor not classify KC block 736 as situated in an area designated as “H2S absent” - an H2S 

contingency plan will be proposed and submitted for approval. This proposed contingency plan would accompany 

the Application for Permit to Drill (APD) for the respective proposed well(s).

(d) MODELING REPORT

H2S concentrations greater than 500 parts per million (ppm) have not been determined or estimated to be 

encountered or handled while conducting the activities proposed in this plan, therefore a modeling report is not 

required for this plan based on the guidelines provided in NTL No. 2008-G04

18
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION E BIOLOGICAL, PHYSICAL, AND SOCIOECONOMIC INFORMATION

(a) HIGH-DENSITY DEEPWATER BENTHIC COMMUNITIES INFORMATION

Geoscience Earth & Marine Services, Inc. ®, (GEMS) was contracted by Chevron to prepare Site Clearance Letters 

for the proposed locations KC 736 A2, A3, and A4. These letters address specific seafloor and subsurface geologic 

conditions near the proposed locations to the Top of Salt. The reports comply with the various Bureau of Ocean 

Energy Management, Regulation, and Enforcement (BOEMRE) Notice to Lessees (NTL’s) 2008-G04, 2008-G05 and 

2009-G40. The proposed wellsites will be required to follow NTL 2008-G06 with respect to pre- and post-spud ROV 

visual inspection surveys.

The proposed wells will be drilled with a dynamically positioned drillship, so there are no associated anchors, anchor 

chain or wire ropes.

High-Density Deepwater Benthic Communities Summary Statements for the proposed surface locations:

KC 736 A2

There is no indication of fluids or gas venting from nearby faults at the seabed. Features or areas that could support 

high-density deepwater benthic communities are not located within 2,000 ft of the proposed location; however, 

scattered deepwater corals were noted in the ROV data near the KC 736-A2 survey location. These “branch-like” 

corals exist on soft substrate and are not considered to be high-density benthic communities that are generally 

associated with hardgrounds. The Seafloor Amplitude Rendering shows normal or ambient amplitudes along the 

seabed at, and near, the proposed wellsite. 

KC 736 A3

There is no indication of fluids or gas venting from nearby faults at the seabed. Features or areas that could support 

high-density deepwater benthic communities are not located within 2,000 ft of the proposed location; however, 

scattered deepwater corals were noted in the ROV data near the KC 736-A3 survey location. These “branch-like” 

corals exist on soft substrate and are not considered to be high-density benthic communities that are generally 

associated with hardgrounds. The Seafloor Amplitude Rendering shows normal or ambient amplitudes along the 

seabed at, and near, the proposed wellsite.

KC 736 A4 

There is no indication of fluids or gas venting from nearby faults at the seabed. Features or areas that could support 

high-density deepwater benthic communities are not located within 2,000 ft of the proposed location. The Seafloor 

Amplitude Rendering shows normal or ambient amplitudes along the seabed at, and near, the proposed wellsite. 

A Non-proprietary copy of the Site Clearance Letters and Maps follows below:

19
10615 SHADOW WOOD DRIVE 

SUITE 200 

HOUSTON, TEXAS 77043 

Phone: (713) 468-1410 

Fax: (713) 468-1438 

E-mail: gems@gemsinc.com

Wellsite KC 736-A2

August 30, 2011 Project No. 0611-1942 

Chevron U.S.A. Inc. 

1500 Louisiana 

Room 5717F 

Houston, TX 77002 

Attention: Mr. Philip Von Dullen III 

Site Clearance Letter 

Proposed Wellsite KC 736-A2 

Block 736 (OCS G-22367) 

Keathley Canyon Area 

Gulf of Mexico 

Chevron U.S.A. Inc., (Chevron) plans to drill an exploration well in Block 736 of the Keathley Canyon (KC) 

Area, Gulf of Mexico. This letter addresses specific seafloor and subsurface geologic conditions to the Top 

of Salt, approximately 1,227 ft below the mudline (bml), at the Proposed Exploration Wellsite KC 736-A2. 

The following discussion is based on findings provided within the main body of the geohazards report for 

Blocks KC 692, 693, 735, 736, and 780 (GEMS Report No. 0109-1600; GEMS, 2009) and within the 

archaeological investigation report for Well KC 736-A2 (GEMS Report No. 0311-1908; GEMS, 2011). 

The surface location of the proposed KC 736-A2 wellsite lies in the northwestern portion of KC 736. 

Chevron provided the following coordinates: 

Proposed Exploration Wellsite KC 736-A2 

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 15 North, U.S. ft Line Reference Block Calls 

X: 1,838,108 Latitude: 26° 15' 42.079743" N Inline: 13615 668 ft FWL 

Y: 9,529,644 Longitude: 92° 23' 47.680062" W Crossline: 5566 6,036 ft FNL 

Chevron will drill this well using a dynamically positioned drilling vessel. Our assessment addresses the 

seafloor conditions within a 2,000-ft radius around the proposed wellsite location. 

Attachments 

The page-size maps and figures accompanying this letter have been extracted from the main report’s original 

maps and 3-D data volume and centered on the proposed well location. 

Map KC736-A2-1: Bathymetry Map 

Map KC736-A2-2: Seafloor Rendering 

Map KC736-A2-3: Seafloor Amplitude Rendering 

Map KC736-A2-4: Geologic Features Map 

Figure KC736-A2-1: ROV Survey Benthic Area 

Figure KC736-A2-2: Portions of Inline 13615 and Crossline 5566 Showing Conditions Beneath 

 Proposed Wellsite KC 736-A2 

Figure KC736-A2-3: Tophole Prognosis Chart, Proposed Wellsite KC 736-A2, Keathley Canyon 

Area, Block 736 

20
Project No. 0611-1942 

- 2 - Wellsite KC 736-A2

NTL Requirements

The following report complies with the Bureau of Ocean Energy Management, Regulation and Enforcement 

(BOEMRE, formerly MMS) Notice to Lessees (NTLs) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). 

The operator will be required to follow NTLs 2008-G04 and –G06 with respect to an ROV monitoring survey 

as well as pre- and post-spud ROV visual inspection surveys (MMS, 2008b and 2008c). 

The Federal lease block KC 736 is not considered archaeologically significant (MMS, 2008d); however, 

pursuant to the “Pre-Seabed Disturbance Survey Mitigation” released by the BOEMRE in March 2011 

(BOEMRE, 2011), an archaeological assessment of the well location will be required before any bottom 

disturbing activities. See GEMS Report No. 0311-1908 (GEMS, 2011) for the archaeological assessment. 

Power Spectrum. According to NTL 2008-G05 (MMS, 2008a), 3-D seismic reflection data may be used for 

shallow hazard assessments with approval from the BOEMRE, Gulf of Mexico Region. A power spectrum 

analysis was conducted from the 3-D seismic data cube provided by Chevron to illustrate the data 

parameters. The power spectrum curve (below) was generated within a 500-ft radius of the intersection of 

the inline and crossline 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.

Power Spectrum Analysis Curve, KC 736, Proposed Wellsite KC 736-A2 

The section of data between the seafloor and the Top of Salt is highly fractured and deformed as a result of 

the shallow salt mass at the proposed wellsite. The close proximity of the salt has likely contributed to lower 

frequency content on the 3-D data. 

21
Project No. 0611-1942 

- 3 - Wellsite KC 736-A2

Man-Made Features

The KC 736 #1 well was drilled by Chevron in 2010 in the southern portion of KC 736, approximately 

11,275 ft southeast of the proposed well location. There are no existing pipelines, cables, or platforms within 

KC 736 or in the immediate surrounding blocks (BOEMRE, 2011a). 

Wellsite Conditions 

The surface location is clear of any constraining conditions within a 2,000-radius circle from the proposed 

wellsite. 

Water Depth, Slope, and Seafloor Sediments. Seafloor conditions are favorable for exploration drilling at 

the proposed wellsite location. The water depth at the proposed surface location is approximately -6,789 ft

(Map KC736-A2-1). The Proposed Wellsite KC 736-A2 lies along an expansive shallow salt ridge. The 

seafloor in this area is irregular as a result of the numerous fault scarps and the deformation of the shallow 

overburden by the underlying salt (Map KC736-A2-2). Several of these fault scarps form a fault-bounded 

low, or graben, that trends generally northwest-southeast at the proposed location. The seafloor at the 

proposed wellsite, however, is generally smooth, dipping to the southeast at about 1.5°. The near-surface 

sediments are expected to be normally consolidated clays forming a drape over the area. 

Deepwater Benthic Communities. There is no indication of fluids or gas venting from nearby faults at the 

seabed. Features or areas that could support high-density deepwater benthic communities are not located 

within 2,000 ft of the proposed location; however, scattered deepwater corals were noted in the ROV data 

near the KC 736-A2 survey location. These “branch-like” corals exist on soft substrate and are not 

considered to be high-density benthic communities that are generally associated with hardgrounds 

(Figure KC736-A2-1). The Seafloor Amplitude Rendering (Map KC736-A2-3) shows normal or ambient 

amplitudes along the seabed at, and near, the proposed wellsite. 

Stratigraphy. Stratigraphic conditions are shown on Figures KC736-A2-2 and KC736-A2-3. The seafloor 

and near-surface sediments at the Proposed Wellsite KC 736-A2 are expected to be hemipelagic and pelagic 

clays and silty clays. In general, the sediments between the seafloor and 480 ft bml (-7,259 ft bsl, below sea 

level) consist of hemipelagic clays and clay-rich turbidite deposits interlayered in places with thin debris 

flow deposits. Thin sand layers are possible within bedded turbidites and mass-transport deposits between 

480 ft bml (-7,269 ft bsl) and 968 ft bml (-7,757 ft bsl). The stratigraphic unit below 968 ft bml (7,757 ft bsl) 

to the Top of Salt at about 1,227 ft bml (-8,016 ft bsl) is likely composed primarily of clay-prone masstransport or debris flow deposits. 

Faults. No seafloor faults are expected to be penetrated by the Proposed Wellsite KC 736-A2; however, 

there are several faults near the proposed surface location (Figures KC736-A2-2 and KC736-A2-3). The 

closest seafloor fault to the proposed wellsite is approximately 777 ft to the west-southwest. The fault trends 

northwest-southeast and is downthrown to the east-northeast, toward the proposed location 

(Map KC736A2-4). 

No other distinct faults were mapped at the Proposed Wellsite KC 736-A2; however, the shallow 

stratigraphic unit above the Top of Salt is likely to be highly fractured as a result of the past motion of the 

underlying shallow salt structure. Other faults are likely to exist that are beyond the resolution of the data. 

Shallow Gas and Shallow Water Flow. Significant shallow gas is not expected at this wellsite within the 

upper 1,227 ft of sediment (Figures KC736-A2-2 and KC736-A2-3). The potential for shallow water flow at 

this well location is considered negligible (Figure KC736-A2-3). 

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 736-A2 ranges 

from negligible to low. The well path will not penetrate any high-amplitude events between the seafloor and 

the Top of Salt (1,227 ft bml), Map KC736-A2-4 and Figure KC736-A2-3. A low potential for encountering 

shallow gas exists from 480 ft bml to the Top of Salt (1,227 ft bml). An increase in amplitude character in 

places may indicate an increase in minor amounts of solution gas within possible thin sand layers within 

22
Project No. 0611-1942 

- 4 - Wellsite KC 736-A2

these intervals. There is a negligible potential for encountering accumulations of shallow gas from the 

remaining sequence at the proposed wellsite. 

Water Flow. There is a negligible potential for shallow water flow within the sedimentary section from 

the seafloor to the Top of Salt (1,227 ft bml), Figure KC736-A2-3. Any thin sand or silty-sand layers 

encountered are not expected to be overpressured. Additionally, the potential for an overpressured 

environment is considerably reduced by faulting and the thin overburden above the shallow salt. 

Closing

The Proposed Wellsite KC 736-A2 in Keathley Canyon Block 736 appears suitable for exploration drilling 

operations. The potential for encountering thin sand layers increases between 480 ft and 968 ft bml, but we 

do not anticipate any significant overpressures associated with this interval. We appreciate the opportunity 

to be of service to Chevron on this project and look forward to working closely with you on other projects. 

Sincerely, 

GEOSCIENCE EARTH & 

MARINE SERVICES, INC. ®

Christopher J. Madere Daniel Lanier 

Senior Geoscientist Vice President - Geoscience 

Attachments (4 Maps and 3 Figures) 

Distribution: Mr. Philip Von Dullen III, Chevron U.S.A. Inc., Houston, TX (5 Copies) 

References: 

Bureau of Ocean Energy Management, Regulation, and Enforcement, 2011, Pre-seabed disturbance survey mitigation, 

released by BOEMRE in March 2011. 

Coffeen, J. A., 1978, Seismic Exploration Fundamentals: Tulsa, the Petroleum Publishing Co., p. 125. 

GEMS, 2009, Geologic and stratigraphic assessment, blocks 692, 693, 735, 736, and 780, Keathley Canyon Area, Gulf 

of Mexico, Geoscience Earth & Marine Services, Inc.®

, Report No. 0109-1600. 

GEMS, 2011, Archaeological ROV Investigation, KC 736-A2 Well, Block 736, Keathley Canyon Area, Gulf of Mexico, 

Geoscience Earth & Marine Services, Inc.®

, Report No. 0311-1908. 

Minerals Management Service, 2008a, Notice to lessees and operators of federal oil, gas, and sulphur leases and pipeline 

right-of-way holders in the outer continental shelf, Gulf of Mexico OCS region, Shallow hazards requirements: U. S. 

Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008-G05. 

Minerals Management Service, 2008b, Notice to lessees and operators of federal oil, gas, and sulphur leases in the outer 

continental shelf, Gulf of Mexico OCS region, Information Requirements for Exploration Plans and Development 

Operations Coordination Documents, U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, 

NTL 2008-G04. 

Minerals Management Service, 2008c, Notice to lessees and operators of federal oil, gas, and sulphur leases in the outer 

continental shelf, Gulf of Mexico OCS region, Remotely operated vehicle surveys in deepwater: U. S. Department of 

the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008-G06. 

23
Project No. 0611-1942 

- 5 - Wellsite KC 736-A2

Minerals Management Service, 2008d, Notice to lessees and operators (NTL) of federal oil and gas leases and pipeline 

right-of-way (ROW) holders on the outer continental shelf (OCS), Gulf of Mexico OCS region (GOMR), Revisions to 

the list of OCS lease blocks requiring archaeological resource surveys and reports: U. S. Department of the Interior, 

Minerals Management Service, Gulf of Mexico, NTL 2008-G20. 

Minerals Management Service, 2010, Notice to lessees and operators of federal oil and gas leases in the outer 

continental shelf, Gulf of Mexico OCS region, Deepwater benthic communities: U. S. Department of the Interior, 

Minerals Management Service, Gulf of Mexico, NTL 2009-G40. Effective Date January 27, 2010. 

24
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26
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28
10615 SHADOW WOOD DRIVE 

SUITE 200 

HOUSTON, TEXAS 77043 

Phone: (713) 468-1410 

Fax: (713) 468-1438 

E-mail: gems@gemsinc.com

Wellsite KC 736-A3

August 30, 2011 Project No. 0611-1942 

Chevron U.S.A. Inc. 

1500 Louisiana 

Room 5717F 

Houston, TX 77002 

Attention: Mr. Philip Von Dullen III 

Site Clearance Letter 

Proposed Wellsite KC 736-A3 

Block 736 (OCS G-22367) 

Keathley Canyon Area 

Gulf of Mexico 

Chevron U.S.A. Inc., (Chevron) plans to drill an exploration well in Block 736 of the Keathley Canyon (KC) 

Area, Gulf of Mexico. This letter addresses specific seafloor and subsurface geologic conditions to the 

possible Top of Salt, approximately 1,157 ft below the mudline (bml), at the Proposed Exploration Wellsite 

KC 736-A3. The following discussion is based on findings provided within the main body of the geohazards 

report for Blocks KC 692, 693, 735, 736, and 780 (GEMS Report No. 0109-1600; GEMS, 2009) and within 

the archaeological investigation report for Well KC 736-A3 (GEMS Report No. 0311-1908; GEMS, 2011). 

The surface location of the proposed KC 736-A3 wellsite lies in the northern portion of KC 736. Chevron 

provided the following coordinates: 

Proposed Exploration Wellsite KC 736-A3 

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 15 North, U.S. ft Line Reference Block Calls 

X: 1,846,245 Latitude: 26° 16' 29.194089" N Inline: 13980 7,035 ft FEL 

Y: 9,534,438 Longitude: 92° 22' 18.015648" W Crossline: 5764 1,242 ft FNL 

Chevron will drill this well using a dynamically positioned drilling vessel. Our assessment addresses the 

seafloor conditions within a 2,000-ft radius around the proposed wellsite location. 

Attachments 

The page-size maps and figures accompanying this letter have been extracted from the main report’s original 

maps and 3-D data volume and centered on the proposed well location. 

Map KC736-A3-1: Bathymetry Map 

Map KC736-A3-2: Seafloor Rendering 

Map KC736-A3-3: Seafloor Amplitude Rendering 

Map KC736-A3-4: Geologic Features Map 

Figure KC736-A3-1: ROV Survey Benthic Area 

Figure KC736-A3-2: Portions of Inline 13980 and Crossline 5764 Showing Conditions Beneath 

 Proposed Wellsite KC 736-A3 

Figure KC736-A3-3: Tophole Prognosis Chart, Proposed Wellsite KC 736-A3, Keathley Canyon 

Area, Block 736 

29
Project No. 0611-1942 

- 2 - Wellsite KC 736-A3

NTL Requirements

The following report complies with the Bureau of Ocean Energy Management, Regulation and Enforcement 

(BOEMRE, formerly MMS) Notice to Lessees (NTLs) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). 

The operator will be required to follow NTLs 2008-G04 and –G06 with respect to an ROV monitoring survey 

as well as pre- and post-spud ROV visual inspection surveys (MMS, 2008b and 2008c). 

The Federal lease block KC 736 is not considered archaeologically significant (MMS, 2008d); however, 

pursuant to the “Pre-Seabed Disturbance Survey Mitigation” released by the BOEMRE in March 2011 

(BOEMRE, 2011), an archaeological assessment of the well location will be required before any bottom 

disturbing activities. See GEMS Report No. 0311-1908 (GEMS, 2011) for the archaeological assessment. 

Power Spectrum. According to NTL 2008-G05 (MMS, 2008a), 3-D seismic reflection data may be used for 

shallow hazard assessments with approval from the BOEMRE, Gulf of Mexico Region. A power spectrum 

analysis was conducted from the 3-D seismic data cube provided by Chevron to illustrate the data 

parameters. The power spectrum curve (below) was generated within a 500-ft radius of the intersection of 

the inline and crossline 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.

Power Spectrum Analysis Curve, KC 736, Proposed Wellsite KC 736-A3 

The section of data between the seafloor and the Top of Salt is highly fractured and deformed as a result of 

the shallow salt mass at the proposed wellsite. The close proximity of the salt has likely contributed to lower 

frequency content on the 3-D data.

30
Project No. 0611-1942 

- 3 - Wellsite KC 736-A3

Man-Made Features

The KC 736 #1 well was drilled by Chevron in 2010 in the southern portion of KC 736, approximately 

14,115 ft south-southwest of the proposed well location. There are no existing pipelines, cables, or platforms 

within KC 736 or in the immediate surrounding blocks (BOEMRE, 2011a). 

Wellsite Conditions 

The surface location is clear of any constraining conditions within a 2,000-radius circle from the proposed 

wellsite. 

Water Depth, Slope, and Seafloor Sediments. Seafloor conditions are favorable for exploration drilling at 

the proposed wellsite location. The water depth at the proposed surface location is approximately -6,616 ft 

(Map KC736-A3-1). The Proposed Wellsite KC 736-A3 lies along an expansive shallow salt ridge. The 

seafloor in this area is irregular as a result of the numerous fault scarps and the deformation of the shallow 

overburden by the underlying salt (Map KC736-A3-2). The seafloor at the proposed wellsite is generally 

smooth, dipping to the northeast at about 10.9°; however, video captured from the ROV investigation shows 

a smooth and gradually dipping seafloor. The near-surface sediments are expected to be normally 

consolidated clays forming a drape over the area. 

Deepwater Benthic Communities. There is no indication of fluids or gas venting from nearby faults at the 

seabed. Features or areas that could support high-density deepwater benthic communities are not located 

within 2,000 ft of the proposed location; however, scattered deepwater corals were noted in the ROV data 

near the KC 736-A3 survey location. These “branch-like” corals exist on soft substrate and are not 

considered to be high-density benthic communities that are generally associated with hardgrounds (Figure 

KC736-A3-1). The Seafloor Amplitude Rendering (Map KC736-A3-3) shows normal or ambient amplitudes 

along the seabed at, and near, the proposed wellsite. 

Stratigraphy. Stratigraphic conditions are shown on Figures KC736-A3-2 and KC736-A3-3. The seafloor 

and near-surface sediments at the Proposed Wellsite KC 736-A3 are expected to be hemipelagic and pelagic 

clays and silty clays. In general, the sediments between the seafloor and the possible Top of Salt (1,157 ft 

bml or -7,773 ft bsl, below sea level) consist of hemipelagic clays and clay-rich turbidite deposits 

interlayered in places with thin debris flow deposits. The sediments within the upper 1,157 ft bml (-7,773 ft 

bsl) likely consist primarily of clays and silts; however, thin sand seams may be interspersed within the 

stratigraphic sequence below 215 ft bml (-6,831 ft bsl). 

Faults. Several seafloor faults exist near the proposed location. A vertical borehole will intersect a seafloor 

fault at approximately 242 ft bml (-6,858 ft bsl), Figures KC736-A3-2 and KC736-A3-3. The fault trends 

northwest to southeast and is downthrown to the northeast. Any further movement along this fault will likely 

be slow, analogous to a soil creep. 

No other seafloor or buried faults are expected to be penetrated; however, the stratigraphic unit above the 

Top of Salt is likely to be highly fractured as a result of the motion of the shallow salt structure. Other faults 

are likely to exist that are beyond the resolution of the data.

Shallow Gas and Shallow Water Flow. Significant shallow gas is not expected at this wellsite within the 

upper 1,157 ft of sediment (Figures KC736-A3-2 and KC736-A3-3). The potential for shallow water flow at 

this well location is considered negligible (Figure KC736-A3-3). 

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 736-A3 ranges 

from negligible to low. The well path will not penetrate any high-amplitude events between the seafloor and 

the possible Top of Salt (1,157 ft bml), Map KC736-A3-4 and Figure KC736-A3-3. A low potential for 

encountering shallow gas exists from 215 ft bml to the possible Top of Salt (1,157 ft bml). An increase in 

amplitude character in places may indicate an increase in minor amounts of solution gas within possible thin 

sand layers within this interval. 

31
Project No. 0611-1942 

- 4 - Wellsite KC 736-A3

Water Flow. There is a negligible potential for shallow water flow within the sedimentary section from 

the seafloor to the possible Top of Salt (1,157 ft bml), Figure KC736-A3-3. Any thin sand or silty-sand 

layers encountered are not expected to be overpressured. Additionally, the potential for an overpressured 

environment is considerably reduced by faulting and the thin overburden above the shallow salt. 

Closing

The Proposed Wellsite KC 736-A3 in Keathley Canyon Block 736 appears suitable for exploration drilling 

operations. Thin sands may be encountered between 215 ft and 1,157 ft bml, but we do not anticipate any 

significant overpressures associated with this interval. We appreciate the opportunity to be of service to 

Chevron on this project and look forward to working closely with you on other projects. 

Sincerely, 

GEOSCIENCE EARTH & 

MARINE SERVICES, INC. ®

Christopher J. Madere Daniel Lanier 

Senior Geoscientist Vice President - Geoscience 

Attachments (4 Maps and 3 Figures) 

Distribution: Mr. Philip Von Dullen III, Chevron U.S.A. Inc., Houston, TX (5 Copies) 

References: 

Bureau of Ocean Energy Management, Regulation, and Enforcement, 2011, Pre-seabed disturbance survey mitigation, 

released by BOEMRE in March 2011. 

Coffeen, J. A., 1978, Seismic Exploration Fundamentals: Tulsa, the Petroleum Publishing Co., p. 125. 

GEMS, 2009, Geologic and stratigraphic assessment, blocks 692, 693, 735, 736, and 780, Keathley Canyon Area, Gulf 

of Mexico, Geoscience Earth & Marine Services, Inc.®

, Report No. 0109-1600. 

GEMS, 2011, Archaeological ROV Investigation, KC 736-A3 Well, Block 736, Keathley Canyon Area, Gulf of Mexico, 

Geoscience Earth & Marine Services, Inc.®, Report No. 0311-1908. 

Minerals Management Service, 2008a, Notice to lessees and operators of federal oil, gas, and sulphur leases and pipeline 

right-of-way holders in the outer continental shelf, Gulf of Mexico OCS region, Shallow hazards requirements: U. S. 

Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008-G05. 

Minerals Management Service, 2008b, Notice to lessees and operators of federal oil, gas, and sulphur leases in the outer 

continental shelf, Gulf of Mexico OCS region, Information Requirements for Exploration Plans and Development 

Operations Coordination Documents, U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, 

NTL 2008-G04. 

Minerals Management Service, 2008c, Notice to lessees and operators of federal oil, gas, and sulphur leases in the outer 

continental shelf, Gulf of Mexico OCS region, Remotely operated vehicle surveys in deepwater: U. S. Department of 

the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008-G06. 

Minerals Management Service, 2008d, Notice to lessees and operators (NTL) of federal oil and gas leases and pipeline 

right-of-way (ROW) holders on the outer continental shelf (OCS), Gulf of Mexico OCS region (GOMR), Revisions to 

the list of OCS lease blocks requiring archaeological resource surveys and reports: U. S. Department of the Interior, 

Minerals Management Service, Gulf of Mexico, NTL 2008-G20. 

32
Project No. 0611-1942 

- 5 - Wellsite KC 736-A3

Minerals Management Service, 2010, Notice to lessees and operators of federal oil and gas leases in the outer 

continental shelf, Gulf of Mexico OCS region, Deepwater benthic communities: U. S. Department of the Interior, 

Minerals Management Service, Gulf of Mexico, NTL 2009-G40. Effective Date January 27, 2010. 

33
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37
10615 SHADOW WOOD DRIVE 

SUITE 200 

HOUSTON, TEXAS 77043 

Phone: (713) 468-1410 

Fax: (713) 468-1438 

E-mail: gems@gemsinc.com

Wellsite KC 736-A4

August 30, 2011 Project No. 0611-1942 

Chevron U.S.A. Inc. 

1500 Louisiana 

Room 5717F 

Houston, TX 77002 

Attention: Mr. Philip Von Dullen III 

Site Clearance Letter 

Proposed Wellsite KC 736-A4 

Block 736 (OCS G-22367) 

Keathley Canyon Area 

Gulf of Mexico 

Chevron U.S.A. Inc., (Chevron) plans to drill an exploration well in Block 736 of the Keathley Canyon (KC) 

Area, Gulf of Mexico. This letter addresses specific seafloor and subsurface geologic conditions to Top of 

Salt, approximately 1,786 ft below the mudline (bml), at the Proposed Exploration Wellsite KC 736-A4. The 

following discussion is based on findings provided within the main body of the geohazards report for Blocks 

KC 692, 693, 735, 736, and 780 (GEMS Report No. 0109-1600; GEMS, 2009). 

The surface location of the proposed KC 736-A4 wellsite lies in the northeastern portion of KC 736. 

Chevron provided the following coordinates: 

Proposed Exploration Wellsite KC 736-A4 

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 15 North, U.S. ft Line Reference Block Calls 

X: 1,850,620 Latitude: 26° 16' 11.62309" N Inline: 13850 2,660 ft FEL 

Y: 9,532,686 Longitude: 92° 21' 30.03370" W Crossline: 5871 2,994 ft FNL 

Chevron will drill this well using a dynamically positioned drilling vessel. Our assessment addresses the 

seafloor conditions within a 2,000-ft radius around the proposed wellsite location. 

Attachments 

The page-size maps and figures accompanying this letter have been extracted from the main report’s original 

maps and 3-D data volume and centered on the proposed well location. 

Map KC736-A4-1: Bathymetry Map 

Map KC736-A4-2: Seafloor Rendering 

Map KC736-A4-3: Seafloor Amplitude Rendering 

Map KC736-A4-4: Geologic Features Map 

Figure KC736-A4-1: Portions of Inline 13850 and Crossline 5871 Showing Conditions Beneath 

 Proposed Wellsite KC 736-A4 

Figure KC736-A4-2: Tophole Prognosis Chart, Proposed Wellsite KC 736-A4, Keathley Canyon 

Area, Block 736 

38
Project No. 0611-1942 

- 2 - Wellsite KC 736-A4

NTL Requirements

The following report complies with the Bureau of Ocean Energy Management, Regulation and Enforcement 

(BOEMRE, formerly MMS) Notice to Lessees (NTLs) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). 

The operator will be required to follow NTLs 2008-G04 and –G06 with respect to an ROV monitoring survey 

as well as pre- and post-spud ROV visual inspection surveys (MMS, 2008b and 2008c). 

The Federal lease block KC 736 is not considered archaeologically significant (MMS, 2008d); however, 

pursuant to the “Pre-Seabed Disturbance Survey Mitigation” released by the BOEMRE in March 2011 

(BOEMRE, 2011a), an archaeological assessment of the well location will be required before any bottom 

disturbing activities. 

Power Spectrum. According to NTL 2008-G05 (MMS, 2008a), 3-D seismic reflection data may be used for 

shallow hazard assessments with approval from the BOEMRE, Gulf of Mexico Region. A power spectrum 

analysis was conducted from the 3-D seismic data cube provided by Chevron to illustrate the data 

parameters. The power spectrum curve (below) was generated within a 500-ft radius of the intersection of 

the inline and crossline 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.

Power Spectrum Analysis Curve, KC 736, Proposed Wellsite KC 736-A4 

The section of data between the seafloor and the Top of Salt is highly fractured and deformed as a result of 

the shallow salt mass at the proposed wellsite. The close proximity of the salt has likely contributed to lower 

frequency content on the 3-D data. 

Man-Made Features

The KC 736 #1 well was drilled by Chevron in 2010 in the southern portion of KC 736, approximately 2.3 

miles southwest of the proposed well location. Drilling has been suspended on the KC 736 #1 well. There 

39
Project No. 0611-1942 

- 3 - Wellsite KC 736-A4

are no existing pipelines, cables, or platforms within KC 736 or in the immediate surrounding blocks 

(BOEMRE, 2011b). 

Wellsite Conditions 

The surface location is clear of any constraining conditions within a 2,000-radius from the proposed wellsite. 

Water Depth, Slope, and Seafloor Sediments. Seafloor conditions are favorable for exploration drilling at 

the proposed wellsite location. The water depth at the proposed surface location is approximately -6,891 ft

(Map KC736-A4-1). The Proposed Wellsite KC 736-A4 lies along an expansive shallow salt ridge. The 

seafloor to the west of the proposed location is irregular as a result of numerous fault scarps, seafloor 

failures, and the deformation of the shallow overburden by the underlying salt (Map KC736-A4-2). The 

seafloor at the proposed wellsite is generally smooth, and dips to the northeast at about 10.8°. The nearsurface sediments are expected to be normally consolidated clays forming a drape over the area. 

Deepwater Benthic Communities. There is no indication of fluids or gas venting from nearby faults at the 

seabed. Features or areas that could support high-density deepwater benthic communities are not located 

within 2,000 ft of the proposed location. The Seafloor Amplitude Rendering (Map KC736-A4-3) shows 

normal or ambient amplitudes along the seabed at, and near, the proposed wellsite. 

Stratigraphy. Stratigraphic conditions are shown on Figures KC736-A4-1 and KC736-A4-2. The seafloor 

and near-surface sediments at the Proposed Wellsite KC 736-A4 are expected to be hemipelagic and pelagic 

clays and silty clays. In general, the sediments between the seafloor and Horizon 10 (486 ft bml) consist of 

hemipelagic clays and clay-rich turbidite deposits interlayered in places with thin debris flow deposits. Thin 

sand layers are possible within bedded turbidites and mass-transport deposits between Horizon 10 

(486 ft bml) and Horizon 30 (816 ft bml). The stratigraphic unit below Horizon 30 (816 ft bml) to the Top of 

Salt at about 1,786 ft bml (-8,677 ft bsl) is likely composed of interlayered clay-prone turbidite and 

mass-transport deposits. 

Faults. Several seafloor faults exist near the proposed location. A vertical borehole will intersect a seafloor 

fault at approximately 1,619 ft bml (Figures KC736-A4-1 and KC736-A4-2). The fault trends northwestsoutheast and is downthrown to the northeast. Any further movement along this fault will likely be slow, 

analogous to a soil creep. 

A vertical borehole will intersect a buried fault at 720 ft bml (Figure KC736-A4-21,). This fault generally 

trends east-west and is downthrown to the north. The shallow stratigraphic unit above the Top of Salt is 

likely to be highly fractured as a result of the past motion of the underlying shallow salt structure. Other 

faults are likely to exist that are beyond the resolution of the data. 

Shallow Gas and Shallow Water Flow. Significant shallow gas is not expected at this wellsite within the 

upper 1,786 ft of sediment (Figures KC736-A4-1 and KC736-A4-2). The potential for shallow water flow at 

this well location is considered negligible (Figure KC736-A4-2). 

Shallow Gas. There is a negligible potential for encountering shallow gas at the Proposed Wellsite 

KC 736-A4. The well path will not penetrate any high-amplitude events between the seafloor and the Top of 

Salt (1,786 ft bml), Map KC736-A4-4 and Figure KC736-A4-2. The closest amplitude event is 

approximately 400 ft north of the proposed location. This event may be associated with an increased amount 

of biogenic gas within possible sand layers between the seafloor and Horizon 10 (486 ft bml). 

Shallow Water Flow. There is a negligible potential for shallow water flow within the sedimentary 

section from the seafloor to the possible Top of Salt (1,786 ft bml), Figure KC736-A4-2. Any thin sand or 

silty-sand layers encountered are not expected to be overpressured. Additionally, the potential for an 

overpressured environment is considerably reduced by faulting and the thin overburden above the shallow 

salt. 

40
Project No. 0611-1942 

- 4 - Wellsite KC 736-A4

Closing

The Proposed Wellsite KC 736-A4 in Keathley Canyon Block 736 appears suitable for exploration drilling 

operations. We appreciate the opportunity to be of service to Chevron on this project and look forward to 

working closely with you on other projects. 

Sincerely, 

GEOSCIENCE EARTH & 

MARINE SERVICES, INC. ®

Carla Cleveland 

Associate Geoscientist 

Erin Williams Janes Daniel Lanier 

Project Manager – Senior Geoscientist Vice President - Geoscience 

Attachments (4 Maps and 2 Figures) 

Distribution: Mr. Philip Von Dullen III, Chevron U.S.A. Inc., Houston, TX (5 Copies) 

References: 

Bureau of Ocean Energy Management, Regulation, and Enforcement, 2011a, Pre-seabed disturbance survey mitigation, 

released by BOEMRE in March 2011. 

Bureau of Ocean Energy Management, Regulation, and Enforcement, 2011b, Free ASCII data files, published on the 

BOEMRE Gulf of Mexico Region homepage, http://www.gomr.boemre.gov/homepg/pubinfo/freeasci/freedesc.html, 

Accessed July 2011. 

Coffeen, J. A., 1978, Seismic Exploration Fundamentals: Tulsa, the Petroleum Publishing Co., p. 125. 

GEMS, 2009, Geologic and stratigraphic assessment, blocks 692, 693, 735, 736, and 780, Keathley Canyon Area, Gulf 

of Mexico, Geoscience Earth & Marine Services, Inc.®

, Report No. 0109-1600. 

Minerals Management Service, 2008a, Notice to lessees and operators of federal oil, gas, and sulphur leases and pipeline 

right-of-way holders in the outer continental shelf, Gulf of Mexico OCS region, Shallow hazards requirements: U. S. 

Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008-G05. 

Minerals Management Service, 2008b, Notice to lessees and operators of federal oil, gas, and sulphur leases in the outer 

continental shelf, Gulf of Mexico OCS region, Information Requirements for Exploration Plans and Development 

Operations Coordination Documents, U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, 

NTL 2008-G04. 

Minerals Management Service, 2008c, Notice to lessees and operators of federal oil, gas, and sulphur leases in the outer 

continental shelf, Gulf of Mexico OCS region, Remotely operated vehicle surveys in deepwater: U. S. Department of 

the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008-G06. 

Minerals Management Service, 2008d, Notice to lessees and operators (NTL) of federal oil and gas leases and pipeline 

right-of-way (ROW) holders on the outer continental shelf (OCS), Gulf of Mexico OCS region (GOMR), Revisions to 

the list of OCS lease blocks requiring archaeological resource surveys and reports: U. S. Department of the Interior, 

Minerals Management Service, Gulf of Mexico, NTL 2008-G20. 

41
Project No. 0611-1942 

- 5 - Wellsite KC 736-A4

Minerals Management Service, 2010, Notice to lessees and operators of federal oil and gas leases in the outer 

continental shelf, Gulf of Mexico OCS region, Deepwater benthic communities: U. S. Department of the Interior, 

Minerals Management Service, Gulf of Mexico, NTL 2009-G40. Effective Date January 27, 2010. 

42
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45
46
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

(b) TOPOGRAPHIC FEATURES MAP

The proposed bottom disturbing activity is greater than 305 meters (1,000 feet) from the “No Activity Zone” of an 

identified topographic feature; therefore the map described in Attachment 2, Section A, Item No. 1 of NTL No. 2004-

G05 is not required for this plan based on the guidelines provided in NTL No. 2008-G04.

(c) TOPOGRAPHIC FEATURES STATEMENT (SHUNTING)

We do not propose to drill two wells from the same surface location outside the 1-mile Zone but within the Protective 

Zone of an identified topographic feature. The statement described in Attachment 2, Section A, Item No.2 of NTL No. 

2004-G05 is not required for this plan based on the guidelines provided in NTL No. 2008-G04.

(d) LIVE BOTTOMS (PINNACLE TREND) MAP

The leases in this proposed plan does not have the Live Bottoms (Pinnacle Trend) stipulation.

(e) LIVE BOTTOMS (LOW RELIEF) MAP

The leases in this proposed plan does not have the Live Bottoms (Low Relief) stipulation.

 

(f) POTENTIALLY SENSITIVE BIOLOGICAL FEATURES

No bottom disturbing activities will be within 30 meters (100 feet) of potentially sensitive biological features. 

Therefore the map described in Attachment 8, Section A of NTL No. 2004-G05 is not required for this plan based on 

the guidelines provided in NTL No. 2008-G04.

(g) REMOTELY OPERATED VEHICLE (ROV) MONITORING SURVEY PLAN

Chevron is aware of requirements of NTL No. 2008-G06 to conduct remotely operated vehicle (ROV) surveys and 

report findings from same in grid areas of inadequate ROV survey coverage as determined by the BOEMRE GOMR. 

Plans are to conduct the survey(s), making biological and physical observations, for the first well drilled, pre-spud, 

post drilling and prior to facility installation, as required by conditions of the letter approving this activity. Transect 

locations will be selected at the time of the activity in accordance with the requirements of the NTL. Equipment will 

include the ROV with video recording capability. Required surveys will be performed according to the guidelines in 

the NTL. Completed MMS-141 forms, videotapes and any other imagery obtained during the survey(s) will be 

submitted within 60 days after the surveys are completed to:

U.S. Department of the Interior 

Bureau of Ocean Energy Management, Regulation and Enforcement

Office of Field Operations

Attention: Plans Section (MS 5231)

1201 Elmwood Park Boulevard

New Orleans, Louisiana 70123-2394

(h) THREATENED OR ENDANGERED SPECIES, CRITICAL HABITAT, AND MARINE MAMMAL INFORMATION

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

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

adversely modify its designated critical habitat.

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

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

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

protected under the Marine Mammal Protection Act (MMPA) in the area of proposes activities under this plan.

47
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

NOAA Fisheries currently lists the Sperm Whale, Leatherback Turtle, Green Turtle, Hawksbill Turtle, and the Kemp’s 

Ridley Turtle as endangered and the Loggerhead Turtle and Gulf Sturgeon as threatened. Currently there are no 

designated critical habitats for the listed species in the Gulf of Mexico Outer Continental Shelf, however, it is possible 

that one or more of these species could be seen in the area of our operations.

(i) ARCHAEOLOGICAL REPORT

The proposed bottom-disturbing activity area has not been identified as a High Probability Shipwreck block or 

prehistoric area.

In the event man-made debris were discovered that appears to indicate the presence of a shipwreck (e.g., a sonar 

image or visual confirmation of an iron, steel, or wooden hull, wooden timbers, anchors, concentrations of man-made 

objects such as bottles or ceramics, piles of ballast rock) within or adjacent to the lease area during the course of 

operations, the Regional Supervisor, Leasing and Environment, will be contacted within 48 hours of its discovery. All 

operations within 305 meters (1,000 ft) of the site will cease until instructed by the Regional Supervisor on the steps 

to take to assess the site’s potential historic significance and the steps to take to protect it

48
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION F WASTE AND DISCHARGE INFORMATION

(a) PROJECTED GENERATED WASTES

(b) PROJECTED OCEAN DISCHARGES

Water Quality Spreadsheets, included below as Attachment F-1, replace the Projected Generated Wastes and the 

Projected Generated Ocean Discharges Tables.

49
please specify if the amount reported is a total or per well amount

Projected generated waste Projected ocean discharges 

Type of Waste 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 synthetic based fluid Cuttings generated while using 

synthetic based drilling fluid.

X bbl/well X bbl/day/well discharge overboard No

Water-based drilling fluid Water-based drilling muds 171,609 bbls 57,203 bbls/well Discharge at mudline prior to riser installation. No

Cuttings wetted with water-based fluid Cuttings coated with water-based 

drilling muds

4,479 bbls 1,493 bbls/well Discharge at mudline prior to riser installation. No

Cuttings wetted with synthetic-based fluid Cuttings coated with Synthetic drilling 

muds, including drilled out cement

22,014 bbls 7,338 bbls/well Treated cuttings will be discharged overboard 

during drilling of SBM interval. Cuttings will pass 

through curttings dryer substantially reducing 

ROC percentage from worst case quoted below. 

Or stored in cutting boxes and transported to 

shore.

No

Will humans be there? If yes, expect conventional waste

EXAMPLE: Sanitary waste water Sanitary waste from living quarters X bbl/well X bbl/hr/well chlorinate and discharge overboard No

Domestic waste Gray water from living quarters,control 

 

169,650 bbls 56,550 bbls/well Food grinder. Starboard Caisson. No

Sanitary waste Sanitary waste from living 

quarters,control rooms, and common 

84,150 bbls 28,050 bbls/well USCG-approved MSD with chlorination. 

Starboard Caisson.

No

Is there a deck? If yes, there will be Deck Drainage

Deck Drainage Deck drainage from drilling floor, 

 

511,650 bbls 170,550 bbls/well Hull discharge overboard. No

Will you conduct well treatment, completion, or workover? 

Well treatment fluids N/A N/A N/A N/A N/A

Well completion fluids Calcium/Zinc Bromide 40,000 bbls 0 N/A No

Workover fluids N/A N/A N/A N/A N/A

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

Desalinization unit discharge Rejected water from watermaker unit 822,150 bbls 274,050 bbls/well Hull discharge overboard. No

Blowout prevent fluid Stackmagic 200/0/5% glycol based on 

2% mixture with potable water

750 bbls 250 bls/well discharge at sea floor, or w/ deck drainage when 

tested on the surface

No

Ballast water Uncontaminated seawater used to 

maintain proper draft

2,312,160 bbls 770,720 bbls/well Hull discharge overboard. No

Bilge water N/A N/A N/A N/A N/A

Excess cement 2,400 bbls 800 bbls/well Discharged at seafloor during riserless drilling No

Fire water Seawater with no addition of chemicals 100,870,650 bbls 224,157 bbls/day Hull discharge overboard. No

Cooling water Seawater with no addition of chemicals 225,000,000 bbls 75,000,000 bbls/well Hull discharge overboard. No

Hydrate control fluid Glycol 75 gals 25 gals/well Discharge at seafloor No

Sub sea wellhead preservation fluid Sub sea wellhead preservation fluid 6 bbls 2 bbls/well Discharge at seafloor No

Leak tracer dye Lignite 63,000 lbs 21,000 lbs/well Discharge at seafloor No

Riser tensioner fluids Riser tensioner fluids 0 0 No

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

Produced water N/A N/A N/A N/A N/A

Will you be covered by an individual or general NPDES permit ? General

TABLE 1. WASTES YOU WILL GENERATE, TREAT AND DOWNHOLE DISPOSE OR DISCHARGE TO 

THE GOM

Projected 

Downhole 

Disposal

50
please specify whether the amount reported is a total or per well

Projected 

generated waste

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: Synthetic-based drilling fluid 

or mud internal olefin, ester

Below deck storage tanks on offshore 

support vessels

Newport Environmental Services 

Inc., Ingleside, TX X bbl/well Recycled

Oil-based drilling fluid or mud N/A N/A N/A N/A N/A

Synthetic-based drilling fluid or mud Synthetic-based drilling 

muds

Internal mud tanks on motor vessel Newpark, Port Fourchon, LA 17,000 bbls/well Transport by boat in cutting 

bins to shorebase; truck to 

disposal facility. Rycycled

Cuttings wetted with Water-based fluid N/A N/A N/A N/A N/A

Cuttings wetted with Synthetic-based fluid Cuttings coated with 

Synthetic drilling muds, 

including drilled out cement

Cuttings box on workboat/crewboat Newpark, Port Fourchon, LA 1.000 bbs/well Transport by boat in cutting 

bins to shorebase; truck to 

disposal facility. Treated and 

landfilled.

Cuttings wetted with oil-based fluids N/A N/A N/A N/A N/A

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

Produced sand N/A N/A N/A N/A N/A

EXAMPLE: trash and debris (recylables) Plastic, paper, aluminum barged in a storage bin ARC, New Iberia, LA X lb/well Recycled

Trash and debris Plastic, paper, aluminum, 

glass, and other refuse

Storage bins on crew boat SWIDI, Leeville, LA 1,800 lbs/day Transport by boat in storage 

bins to shorebase. Landfilled.

Wash water Transport by boat in tanks to shorebase Newpark, Port Fourchon, LA 2-5 bbls/day Transport by boat in cutting 

bins to shorebase; truck to 

disposal facility. Injected.

Chemical product wastes Used oil, hazardous waste Drums on crew boat Chemical Waste Management, 

Sulfur, La; WMI Woodside, 

Walker, LA; Aaron Oil, Saraland, 

AL

3 bbls/day Transport in drums on crew 

boat to shorebase; truck to 

disposal facility. Recycled or 

incinerated.

Completion Fluids Calcium/Zinc Bromide Excess fluid transported by boat in 

tanks to shorebase

M-I Swaco, Fourchon, LA 2,000 bbls/well Recycled

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

Waste Disposal

TABLE 2. WASTES YOU WILL TRANSPORT AND /OR DISPOSE OF ONSHORE 

Will you have additional wastes that are not permitted for discharge? If 

yes, fill in the appropriate rows. 

51
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION G AIR EMISSIONS INFORMATION

EMISSIONS WORKSHEETS AND SCREENING QUESTIONS

The Complex Total Emissions are the same as the Plan Emissions, and therefore only one set of emissions 

calculations is included. Emissions from the proposed location are estimated using the EPA Publications referenced 

in the tables. 

The calculated emissions estimates shown in this plan are based on the worst case emissions using a drillship. 

Included in this section as attachment G-1 is the Projected Air Quality Emissions Report worksheets (Form MMS138). 

SCREENING QUESTIONS FOR EP’S YES NO

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

exploration activities more than 90% of the amounts calculated using the following formulas: CT = 

3400D2/3 for CO, and CT = 33.3D for the other pollutants (where D = distances to shore in miles)?

Do your emissions calculations include any emission reduction measures or modified emissions 

factors?

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

Do you expect to encounter H2S at concentrations greater than 20 parts per million (ppm)?

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

well?

Do you propose to burn produced hydrocarbon liquids?

52
COMPANY Chevron U.S.A. Inc.

AREA Keathley Canyon

BLOCK 736

LEASE OCS-G 22367

PLATFORM Drillship

WELL 3-Wells

COMPANY CONTACT Philip Von Dullen III

TELEPHONE NO. (832) 854-3644

REMARKS Revised Exploration Plan (EP) 9/29/2011

53
EMISSIONS FACTORS

Form MMS-138 (March 2000)

Page 2 of 6

KC 736 Moccasin REP Air Emissions 9_29_11.xls

1:35 PM 9/29/2011

Fuel Usage Conversion Factors Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine REF. DATE

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

Equipment/Emission Factors units OCS-G 22367 SOx NOx VOC CO REF. DATE

NG Turbines gms/hp-hr 5-Wells 0.00247 1.3 0.01 0.83 AP42 3.2-1& 3.1-1 10/96

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

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

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

Diesel Recip. < 600 hp. gms/hp-hr 1 1.468 14 1.12 3.03 AP42 3.3-1 10/96

Diesel Recip. > 600 hp. gms/hp-hr 0.32 1.468 11 0.33 2.4 AP42 3.4-1 10/96

Diesel Boiler lbs/bbl 0.084 2.42 0.84 0.008 0.21 AP42 1.3-12,14 9/98

NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 P42 1.4-1, 14-2, & 14 7/98

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

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

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

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

Glycol Dehydrator Vent lbs/mmscf 6.6 La. DEQ 1991

Gas Venting lbs/scf 0.0034

Sulfur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.4 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

54
EMISSIONS CALCULATIONS 2ND YEAR

Form MMS-138 (March 2000)

Page 4 of 6 KC 736 Moccasin REP Air Emissions 9_29_11.xls

1:35 PM 9/29/2011

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Chevron U.S.A. Inc. Keathley Canyon 736 OCS-G 22367 Drillship 3-Wells Philip Von Dullen III (832) 854-3644 Revised Exploration Plan (EP) 9/29/2011

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

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

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

DRILLING PRIME MOVER>600hp diesel 9772 471.9876 11327.70 24 335 6.89 31.60 236.77 7.10 51.66 27.69 127.02 951.80 28.55 207.67

PRIME MOVER>600hp diesel 9772 471.9876 11327.70 24 335 6.89 31.60 236.77 7.10 51.66 27.69 127.02 951.80 28.55 207.67

PRIME MOVER>600hp diesel 9772 471.9876 11327.70 24 335 6.89 31.60 236.77 7.10 51.66 27.69 127.02 951.80 28.55 207.67

PRIME MOVER>600hp diesel 9772 471.9876 11327.70 24 335 6.89 31.60 236.77 7.10 51.66 27.69 127.02 951.80 28.55 207.67

PRIME MOVER>600hp diesel 6515 314.6745 7552.19 24 335 4.59 21.07 157.85 4.74 34.44 18.46 84.69 634.57 19.04 138.45

PRIME MOVER>600hp diesel 6515 314.6745 7552.19 24 335 4.59 21.07 157.85 4.74 34.44 18.46 84.69 634.57 19.04 138.45

Emergency Generator-diesel 3257 157.3131 3775.51 1 335 2.30 10.53 78.91 2.37 17.22 0.38 1.76 13.22 0.40 2.88

BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(crew) 5200 251.16 6027.84 16 48 3.67 16.81 125.99 3.78 27.49 1.41 6.46 48.38 1.45 10.56

VESSELS>600hp diesel(supply) 5200 251.16 6027.84 16 335 3.67 16.81 125.99 3.78 27.49 9.82 45.06 337.66 10.13 73.67

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(crew) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(supply) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 0.00

DRILLING OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

WELL TEST GAS FLARE 1875000 24 21 1.11 133.88 113.06 728.44 0.28 33.74 28.49 183.57

2012 YEAR TOTAL 46.36 213.79 1727.54 160.87 1076.15 159.29 731.02 5509.33 192.76 1378.24

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 7192.80 7192.80 7192.80 7192.80 122400.00

216.0

55
EMISSIONS CALCULATIONS 3RD YEAR

Form MMS-138 (March 2000)

Page 5 of 6 KC 736 Moccasin REP Air Emissions 9_29_11.xls

1:35 PM 9/29/2011

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Chevron U.S.A. Inc. Keathley Canyon 736 OCS-G 22367 Drillship 3-Wells Philip Von Dullen III (832) 854-3644 Revised Exploration Plan (EP) 9/29/2011

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

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

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

DRILLING PRIME MOVER>600hp diesel 9772 471.9876 11327.70 24 115 6.89 31.60 236.77 7.10 51.66 9.51 43.60 326.74 9.80 71.29

PRIME MOVER>600hp diesel 9772 471.9876 11327.70 24 115 6.89 31.60 236.77 7.10 51.66 9.51 43.60 326.74 9.80 71.29

PRIME MOVER>600hp diesel 9772 471.9876 11327.70 24 115 6.89 31.60 236.77 7.10 51.66 9.51 43.60 326.74 9.80 71.29

PRIME MOVER>600hp diesel 9772 471.9876 11327.70 24 115 6.89 31.60 236.77 7.10 51.66 9.51 43.60 326.74 9.80 71.29

PRIME MOVER>600hp diesel 6515 314.6745 7552.19 24 115 4.59 21.07 157.85 4.74 34.44 6.34 29.07 217.84 6.54 47.53

PRIME MOVER>600hp diesel 6515 314.6745 7552.19 24 115 4.59 21.07 157.85 4.74 34.44 6.34 29.07 217.84 6.54 47.53

Emergency Generator-diesel 3257 157.3131 3775.51 1 115 2.30 10.53 78.91 2.37 17.22 0.13 0.61 4.54 0.14 0.99

BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(crew) 5200 251.16 6027.84 16 17 3.67 16.81 125.99 3.78 27.49 0.50 2.29 17.13 0.51 3.74

VESSELS>600hp diesel(supply) 5200 251.16 6027.84 16 115 3.67 16.81 125.99 3.78 27.49 3.37 15.47 115.91 3.48 25.29

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(crew) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(supply) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 0.00

DRILLING OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

WELL TEST GAS FLARE 1875000 24 21 1.11 133.88 113.06 728.44 0.28 33.74 28.49 183.57

2013 YEAR TOTAL 46.36 213.79 1727.54 160.87 1076.15 54.70 251.20 1913.94 84.90 593.79

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 7192.80 7192.80 7192.80 7192.80 122400.00

216.0

56
SUMMARY

Page 1 of 1

COMPANY AREA BLOCK LEASE PLATFORM WELL

Chevron U.S.A. Inc. Keathley Canyon 736 OCS-G 22367 Drillship 3-Wells

Emitted Substance

Year

PM Sox NOx VOC CO

2012 159.29 731.02 5509.33 192.76 1378.24

2013 54.70 251.20 1913.94 84.90 593.79

2014 0.00 0.00 0.00 0.00 0.00

2015 0.00 0.00 0.00 0.00 0.00

2016 0.00 0.00 0.00 0.00 0.00

2017 0.00 0.00 0.00 0.00 0.00

2018 0.00 0.00 0.00 0.00 0.00

2019 0.00 0.00 0.00 0.00 0.00

2020 0.00 0.00 0.00 0.00 0.00

2021 0.00 0.00 0.00 0.00 0.00

Allowable 7192.80 7192.80 7192.80 7192.80 122400.00

57
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION H OIL SPILLS INFORMATION

(a) OIL SPILL RESPONSE PLANNING

REGIONAL OSRP INFORMATION

All the proposed activities and facilities in this EP will be covered by the Oil Spill Response Plan, filed by Chevron 

Corporation, BOEMRE company number 02335, in accordance with 30 CFR 254, approved April 15, 2010. Chevron 

submitted a Revised Regional Oil Spill Response Plan to the BOEMRE on February 24, 2011. 

The Worst Case Discharge Scenario for “Mobile Rig Exploration Drilling Operations” for GC 640 well PS006 was 

reviewed under Plan Number R-5101 and certification accepted on March 11, 2011.

Chevron’s Worst Case Discharge number for this plan, submitted in revised plan R-5096, was accepted by the 

BOEMRE on January 26, 2011.

SPILL RESPONSE SITES

In the table below, information is provided on the location of the primary spill response equipment and the location of 

the planned staging area(s) that would be used should an oil spill occur resulting from activities proposed in this plan.

Primary Response Equipment Location Preplanned Staging Location(s)

Leeville, LA Leeville, LA

OIL SPILL REMOVAL ORGANIZATION (OSRO) INFORMATION

Clean Gulf Associates (CGA) and Marine Spill Response Corporation (MSRC) are our primary oil spill removal 

organizations that will supply equipment and personnel. CGA and MSRC have equipment pre-staged around the 

Gulf of Mexico. The major locations of this equipment are Lake Charles, Houma, Fort Jackson and Venice, 

Louisiana; Galveston and Ingleside, Texas; and Pascagoula, Mississippi.

58
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

(a) WORST CASE DISCHARGE COMPARISON TABLE

The table below provides a comparison of the worst-case scenario from Chevron’s proposed Regional OSRP with 

the worst-case scenario from the proposed activities in this plan

Category

Regional OSRP “Mobile 

Rig Exploration Drilling 

Ops.” Worst-Case 

Discharge Scenario

EP 

Type of Activity (Types of activities 

include pipeline, platform, caisson, subsea 

completion or manifold, and mobile drilling 

rig)

Exploratory Drilling Exploratory Drilling

Spill Location (area/block)

Green Canyon Block 640 Keathley Canyon Block 736

Facility Designation (e.g., Well No. 2, 

Platform JA, Pipeline Segment No. 6373)

GC 640 PS006 KC 736 “A”

Distance to Nearest Shoreline 118 miles 216 miles

Volume

Uncontrolled blowout (volume per day) 186,452 barrels 51,650 barrels

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

diesel)

Crude Oil Crude Oil

Gravity(s) API - (Provide API gravity of 

all oils given under “Type of Oil(s)” above.

Estimate for EP’s)

30o 28o 

Since Chevron has the capability to respond to the appropriate worst-case spill scenario included in its revised 

Regional OSRP submitted on February 24, 2011, and since the worst-case scenario determined for our EP does not 

replace the appropriate worst-case scenario in our revised Regional OSRP, we hereby certify that Chevron has the 

capability to respond, to the maximum extent practicable, to a worst case discharge, or a substantial threat of such a 

discharge, resulting from the activities proposed in our Plan.1

 

(b) SPILL RESPONSE DISCUSSION

Oil spill response related activities for facilities included in this document are governed by the Chevron Gulf of Mexico 

Business Unit Regional Oil Spill Response Plan (OSRP). This OSRP meets all requirements contained in 30 CFR 

250. The existing Chevron Regional OSRP was approved by BOEMRE on April 19, 2010. Chevron submitted a 

revised OSRP to the BOEMRE on February 24, 2011. The below information is from the Chevron revised OSRP. 

Chevron also submitted to the BOEMRE Regional Supervisor, in accordance with 30 CFR 254.2(b), a letter dated 

October 22, 2010 stating that Chevron has the capability to respond, to the maximum extent practicable, to a worst 

case discharge or a substantial threat of such a discharge for all Chevron Gulf of Mexico facilities. The Chevron Gulf 

of Mexico Business Unit Regional OSRP encompasses all facilities operated by Chevron, U.S.A. Inc. and, herein the 

jurisdiction of the BOEMRE. 

 

1 This certification is provided as required by NTL No. 2008-G04 at page 19.

59
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

The worst case discharge for Keathley Canyon 736 is 51,650 barrels per day. This was calculated using the 

guidance provided in NTL 2010-N06. 

Response Discussion (§ 256.26 (d))

Chevron maintains numerous resources, equipment and expertise to respond to an oil spill in the Gulf of Mexico. 

Chevron has oil spill response service contracts with both local and international companies and cooperatives, and 

has a large corps of dedicated Chevron emergency responders that can work in the Gulf of Mexico. Chevron has 

contracts with the following oil spill response service providers.

Oil Spill Removal Organizations (OSRO). These companies have on-hand shoreline protection and cleanup 

equipment to respond to a spill in the Gulf of Mexico. 

• Oil Mop LLC

• U.S. Environmental Services

• ES&H Consulting

• American Pollution Control

Oil Spill Cooperatives (OSC). OSCs have equipment pre-staged in the Gulf of Mexico including Lake Charles, 

Intracoastal City, Houma, Grand Isle, Fort Jackson and Venice, Louisiana; Galveston, Texas; and Pascagoula, 

Mississippi. OSCs provide resources to respond to offshore incidents including areas identified in this permit.

• Clean Gulf Associates (CGA) – This major cooperative strictly dedicated to Gulf of Mexico oil and gas 

developers and producers. 

• Marine Spill Response Corporation (MSRC) – This national cooperative has extensive dedicated offshore 

resource located in the Gulf of Mexico

• Clean Caribbean and Associates (CCA) – This is a major cooperative located in the Caribbean. 

• Oil Spill Response, Ltd. (OSR) – This one of the largest international cooperatives operating out of the UK, 

Bahrain and Singapore. 

Well Control Emergency Response Companies

• Wild Well Control Inc.

• Boots & Coots 

• IWC Services, Inc.

Oil Spill Management and Response Consultants 

• O’Brien’s Oil Pollution Services

• The Response Group (TRG) 

Chemical Dispersant Companies (capable of delivering air and vessel dispersants) 

• Airborne Support, Inc 

• MSRC

• CCA

• OSRL

60
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

Chevron has numerous staging areas in the Gulf of Mexico including Chevron’s three shorebases located in 

Intracoastal City, Leeville and Venice, Louisiana. Other staging areas will be pursued as warranted by any specific 

response. Chevron primary equipment locations are located Leeville, Houma, Fourchon, Venice, Lake Charles, L 

and Pascagoula, MS. 

Chevron uses a layered approach to respond to a worst case discharge from its Tahiti facility by conducting 

simultaneous response operations at the well site, in the offshore environment and in nearshore and shoreline 

areas. Plans will be implemented, resources deployed and response operations established within these 

environmental areas to accomplish the following objectives:

• Ensure the safety of responders and the general public

• Intervene at the well site to stop the flow of oil 

• Minimize the spread of oil at the surface 

• Minimize encroachment to the coastline environment

• Protect coastal and natural resources 

Upon notification of a worst case discharge oil spill at the location listed in this permit Chevron will mobilize resources 

listed in the attached enclosures. This information comes directly from the Chevron Gulf of Mexico Business Unit 

Regional Oil Spill Response Plan and relates to a worst case discharge volume of 186,452 barrels per day that could 

occur at a Chevron facility located in Green Canyon 641. These same assets would be mobilized to all sites 

contained in this permit. The on water recovery vessels, barges and systems listed below have an effective daily 

recovery capacity of 816,651 barrels per day. 

Chevron will also take the following general actions to mobilize and coordinate response operations:

• Set up and staff its command center in Covington, LA

• Set up a source control group in Houston, TX, or Covington, LA

• Mobilize well site resources to cap, contain and disperse oil at the well head

• Mobilize assets to drill relief wells

• Mobilize assets to contain and collect surface oil at the well site and in the offshore environment

• Mobilize assets to disperse and burn surface oil at the well site and in the offshore environment

• Establish a deepwater staging area from a LA port or location

• Deploy assets to track the movement of oil on the surface

Follow up actions will include the following:

• Locate, monitor, track and project the movement of the oil spill

• Mobilize nearshore skimming and booming vessels, barges and systems to shorebase locations for rapid 

deployment in the nearshore environment

• Mobilize oil spill removal organization (OSRO) resources and assets to staging areas for rapid deployment 

of shoreline protection resources

• Mobilize wildlife protection and rehabilitation resources to staging areas for rapid deployment of resources

• Determine Incident Command Post (ICP) locations based on intervention operations and results and surface 

oil spill trajectories

• Determine ICP Operations Branch locations based on intervention operations and results and surface oil 

spill trajectories

• Determine additional staging areas based on the spill trajectory

Offshore On-Water Collection and Storage

61
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

The following vessels and barges will be deployed to collect and store on-water oil. This information is taken directly 

from Appendix H to the Chevron OSRP (pages Appendix H-74 through 82). 

Vessel or Barge EDRC Storage Capacity

MSRC LA Responder 10,567 4,000

MSRC Gulf Coast Responder 10,567 4,000

MSRC TX Responder 10,567 4,000

MSRC MS Responder 10,567 4,000

MSRC Southern Responder 10,567 4,000

MSRC FL Responder 10,567 4,000

MSRC VA Responder 10,567 4,000

CGA HOSS Barge 43,000 4,000

MSRC Offshore Barge 452 45,000

MSRC Offshore Barge 570 56,900

MSRC Offshore Barge 402 40,300

MSRC Offshore Barge 403 40,300

MSRC Offshore Barge 360 36,000

MSRC Offshore Barge 350 35,000

MSRC Offshore Barge 680 68,000

MSRC Offshore Barge 401 40,000

MSRC Offshore Barge 381 38,000

MSRC Offshore Barge 520 52,000

MSRC Offshore Barge 620 62,000

These assets have more than adequate EDRC and large storage capabilities to collect and store a 51,650 barrel per 

day oil spill. These large skimming and storage assets maximize Chevron’s ability to collect and store oil and 

minimize time needed to offload oil from the skimming vessels to storage. 

Other offshore mechanical skimming assets (Koseq skimming arms, Fast Response Units, deployable skimmers) 

that require a vessel of opportunity will be deployed as secondary assets to collect surface oil. Additionally, Clean 

Gulf Associates has signed an agreement with K-Sea Transportation to access their offshore tank barges to store 

recovered oil during an offshore spill. The attached agreement details K-Sea storage capabilities. These storage 

barges will be coupled with Koseq skimming systems to effectively collect and store surface oil. 

Shoreline Protection

OSRAM projects that there is a 2% chance that an oil spill from KC 736 could reach Matagorda and Galveston 

Counties and Cameron Parish within 30 days. 

The May 2, 2010 State of Louisiana Deepwater Horizon Incident plan identified 21,798’ of protective boom were 

needed to protect Cameron Parish. Coast Guard ACPs do not provide similar information for Matagorda and 

Galveston Counties. Chevron has developed Shoreline Response Guides that detail tactical strategies to protect and 

clean impacted land areas. Our guides indicate that 5,400’ of boom is needed to protect Matagorda County and 

34,900’ of boom is needed to protect Galveston County. A total of 62,098’ of boom are therefore needed to protect 

these three areas. 

Chevron has contracts with four major Oil Spill Removal Organizations (OSRO) who provide shoreline protection and 

cleanup services: AMPOL, Oil Mop, U.S. Environmental Services and ES&H. These four OSROs have a combined 

62
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

113,450’ of containment boom located in the Gulf of Mexico (see table on page Appendix H – 94 to the Chevron 

OSRP) that can be immediately deployed to Matagorda County, Galveston County and Cameron Parish. This boom 

is sufficient to protect the two counties and one parish.

Additionally, Oil Stop, a wholly-owned subsidiary of AMPOL, manufactures offshore and shoreline protection boom. 

Chevron through the service contract with AMPOL can quickly obtain additional boom that can be deployed within the 

30 day predicted landfall of oil to these areas. 

63
Chevron U.S.A. Inc. PUBLIC INFORMATION

KC 736 REP

SECTION I ENVIRONMENTAL MONITORING INFORMATION

(a) MONITORING SYSTEMS 

The Drillship is installed with surface current monitoring equipment. This equipment is a 75 kHz Acoustic Doppler 

Current Profile (ADCP) unit. This unit monitors current to a depth of 603 meters / 1,978’. The data from this meter is 

reported to the BOEMRE via the NDBC website.

(b) INCIDENTAL TAKES 

There is no reason to believe that any of the endangered species or marine mammals as listed in the ESA will be 

“taken” as a result of the operations proposed under this plan.

(c) FLOWER GARDEN BANKS NATIONAL MARINE SANCTUARY

No activities proposed in this plan will be conducted within the Protective Zones of the Flower Garden Banks and 

Stetson Bank.

SECTION J LEASE STIPULATIONS INFORMATION

There are no stipulations assigned to this lease. However, Chevron will follow all guidelines to implement mitigation 

measures to reduce the potential taking of federally protected species.

SECTION K ENVIRONMENTAL MITIGATION MEASURES INFORMATION

(b) INCIDENTAL TAKES

Chevron will adhere to the requirements 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 and Elimination”

NTL 2007-G02, “Implementation of Seismic Survey Mitigation Measures and Protected Species Observer Program”

SECTION L SUPPORT VESSELS AND AIRCRAFT INFORMATION

(a) GENERAL

In the table below, information is provided regarding the vessels (e.g., tug boats, anchor-handling vessels, 

construction barges, lay barges, supply boats, crew boats) and aircraft you will use to support your proposed 

activities. If specific vessels have not yet been determined, use the maximum capacities, numbers, and trip 

frequencies for the types of vessels you will use.

Type Maximum Fuel Tank 

Storage Capacity

Maximum No. in Area at 

Any Time

Trip Frequency or 

Duration

Crew Boat 47,382 gals. One Once per week

Supply Boat 303,093 gals. Two Every 2 to 3 days

Helicopter 2,800 lbs. / 430 gals. One 7 trips per week

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KC 736 REP

(b) DIESEL OIL SUPPLY VESSELS

Information on the vessels used to supply diesel oil. Any vessels that will transfer diesel oil you will use for purposes 

other than fuel.

Size of Fuel Supply 

Vessel

Capacity of Fuel Supply 

Vessel

Frequency of Fuel 

Transfers

Route Fuel Supply 

Vessel Will Take

280 foot 860,000 gals quarterly From shore base to block

280 foot 275,000 gals 4-6 weeks From shore base to block

(d) SOLID AND LIQUID WASTES TRANSPORTATION

Water Quality Spreadsheets, included as Attachment F-1, replace the Solid and Liquid Wastes Transportation Table.

(e) VICINITY MAP

A map showing the location of the proposed activities relative to the shoreline, the distance of the proposed activities 

from the shoreline, and the primary route(s) of the support vessels and aircraft you will use when traveling between 

the onshore support facilities and the drilling unit is provided as attachment L-1 at the end of this section.

ATTACHMENTS TO SECTION L

• L-1 – Vicinity Map

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South Marsh Island 

North

Walker Ridge

Garden Banks Green Canyon

Vermilion

Keathley Canyon

Eugene Island

Lund

Ship Shoal South

South Timbalier

Vermilion South

Ewing Bank

Grand Isle

Eugene Island South

South Timbalier South

Burns Houma

Dulac

Fourchon

Galliano

Cocodrie

Grand Isle

River Ridge

Chevron U.S.A. Inc. Vicinity Map

Keathley Canyon 736

KC736

~245 Miles to Leeville, LA Shorebase

~216 Miles to Shore

Leeville

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SECTION M ONSHORE SUPPORT FACILITIES INFORMATION 

(a) GENERAL

The table below provides a listing of the onshore facilities that will be used to provide supply and service support for 

the proposed activities.

Name Location Existing/New/Modified

Chevron USA Leeville Shore Base Leeville, Louisiana Existing

C-Port Shorebase- Port Fourchon Fourchon, Louisiana Existing

(b) SUPPORT BASE CONSTRUCTION OR EXPANSION

Chevron will use its existing onshore base facility located in Leeville, Louisiana. The base has adequate facilities for 

marine and air transportation to accommodate the activities proposed in this plan. The proposed operations do not 

require expansion or modifications to the base.

(d) WASTE DISPOSAL

Water Quality Spreadsheets, included as Attachment F-1, replace the Waste Disposal Table.

SECTION N COASTAL ZONE MANAGEMENT ACT (CZMA) INFORMATION

(a) CONSISTENCY CERTIFICATION

The State of Louisiana found Revised EP R-5096 consistent with the Louisiana Coastal Resources program as 

required by Section 307 (3) (B) of the Coastal Zone Management Act of 1972. 

A Coastal Zone Management Act consistency certification for this plan is included below for the State of Louisiana.

(b) OTHER INFORMATION

To the best of our knowledge, the set of findings included in the Environmental Impact Analysis and this Exploration 

Plan indicate that the proposed activity and its associated facilities and effects are all consistent with, and comply 

with, the provisions and guidelines of the Louisiana Coastal Resources Program (LCRP). The proposed activity will 

be conducted in a manner consistent with such program. 

SECTION O ENVIRONMENTAL IMPACT ANALYSIS (EIA)

The project-specific EIA was included with Plan N-9380. 

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SECTION P ADMINISTRATIVE INFORMATION

(a) EXEMPTED INFORMATION

Proprietary information included in the proprietary copy of this EP.

• BHL, TVD, and MD information on form MMS-137 (OCS Plan Information Form)

• All items and enclosures under Geological and Geophysical Information

(b) BIBLIOGRAPHY

Any previously submitted EP, DPP, or DOCD; study report; survey report; or other material referenced in this EP or 

its accompanying information, is listed below:

• Initial Exploration Plan (EP), N-9380, Keathley Canyon Area (KC) Block 736 (OCS-G 22367), submitted by 

Chevron U.S.A. Inc. and approved June 8, 2009. 

• Revised EP, R-5096, KC Block 736 (OCS-G 22367), submitted by Chevron and approved July 29, 2011.

• Chevron’s Regional Oil Spill Response Plan

• Geologic and Stratigraphic Assessment over Keathley Canyon Blocks 692, 693, 735, 736, and 780, prepared 

by Geoscience Earth & Marine Services, Inc. ®, (GEMS) for Chevron U.S.A. Inc. (Chevron) in April 2009. 

The report was submitted with the initial plan, N-9380.

• Site Clearance Letters, Block 736 (OCS-G 22367), Keathley Canyon Area, Gulf of Mexico, Geoscience Earth 

& Marine Services, Inc. ®, (GEMS), August 30, 2011. The site clearance letters were submitted with the 

initial submittal of this revised plan, R-5299.

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