10615 Shadow Wood Drive 

Suite 200 

Houston, Texas 77043 

(713) 468-1410 (o) 

(713) 468-1438 (f) 

www.gemsinc.com

Geoscience Earth & Marine Services, Inc. ® // 1 

FORUM ENERGY TECHNOLOGIES, INC.

July 10, 2012 Project No. 0412-2080 

Chevron U.S.A. Inc. 

1500 Louisiana 

Room 5717F 

Houston, Texas 77002 

Attention: Mr. Philip Von Dullen III 

Site Clearance Letter 

Proposed Wellsite KC 692-B 

Block 692 (OCS G-25801) 

Keathley Canyon Area, Gulf of Mexico 

Chevron U.S.A. Inc., (Chevron) plans to drill an exploration well in Block 692 of the Keathley Canyon (KC) 

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

of approximately 5,760 ft below the mudline (bml), at the Proposed Exploration Wellsite KC 692-B. 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 and within the archaeological ROV assessment (GEMS Report Nos. 

0109-1600 and 0112-2040; GEMS, 2009 and 2012 respectively). 

The surface location of the proposed KC 692-B wellsite lies in the southeastern portion of KC 692. Chevron 

provided the following coordinates: 

Proposed Exploration Wellsite KC 692-B

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 15 North, U.S. ft 

Line 

Reference 

Block Calls 

KC 692 

X: 1,849,304 Latitude: 26o 17' 29.15597" N Inline: 14445 3,976 ft FEL 

Y: 9,540,505 Longitude: 92o 21' 44.07129" W Crossline: 5839 4,825 ft FSL 

Chevron plans to 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 No. KC692-B-1. Bathymetry Map 

• Map No. KC692-B-2. Seafloor Rendering 

• Map No. KC692-B-3. Seafloor Amplitude Rendering 

• Map No. KC692-B-4. Geologic Features Map 

• Figure KC692-B-1. Portions of Inline 14445 and Crossline 5839 Showing Conditions 

 Beneath Proposed Wellsite KC 692-B 

• Figure KC692-B-2. Tophole Prognosis Chart, Proposed Wellsite KC 692-B, Keathley 

 Canyon Area, Block 692 

 

29
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 2 

FORUM ENERGY TECHNOLOGIES, INC.

NTL Requirements

The following report complies with the Bureau of Ocean Energy Management (BOEM, formerly MMS) 

Notice to Lessees (NTL’s) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). The operator will be required 

to follow NTL’s 2008-G04 and -G06 with respect to an ROV monitoring survey as well as pre- and postspud ROV visual inspection surveys (MMS, 2008b and 2008c). 

The Federal lease Block KC 692 is not considered archaeologically significant (BOEM, 2011); 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. GEMS submitted an archaeological ROV assessment for Keathley Canyon Block 692 

to Chevron in March 2012 (GEMS, 2012). This archaeological ROV assessment satisfies the BOEMRE 

requirement. 

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 BOEM, 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 location. 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 692, Proposed Wellsite KC 692-B 

Man-Made Features

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

3.9 miles southwest of the proposed well location. The KC 736 #1 well is permanently abandoned. There 

are no existing pipelines, cables, or platforms within KC 692 or in the immediate surrounding blocks 

(BOEM, 2012). 

0

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0.3

0.4

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0.7

0.8

0.9

1

0 10 20 30 40 50 60 70 80 90 100

Power (Amp2

)

Frequency (Hz)

POWER SPECTRUM

30
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 3 

FORUM ENERGY TECHNOLOGIES, INC.

Wellsite Conditions 

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

proposed wellsite. 

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

drilling at the proposed wellsite location. The water depth at the proposed surface location is approximately 

-7,125 ft (Map KC692-B-1). The seafloor at the proposed wellsite is generally smooth, and dips to the eastnortheast at a fairly steep inclination of 9.9°. The ROV data confirms a relatively smooth mud bottom 

across the proposed well location. The near-surface sediments are expected to be normally consolidated 

clays forming a drape over the area. The Proposed Wellsite KC 692-B is situated along the flank of a 

broad intraslope basin named Chalmette Basin. An expansive shallow salt ridge lies approximately 2,000 ft 

west-southwest of the proposed well location. The seafloor along the salt ridge is irregular as a result of 

numerous fault scarps, seafloor failures, and the deformation of the shallow overburden by the underlying 

salt (Map KC692-B-2). 

A shallow slope failure scarp lies approximately 100 ft to the west of the proposed location. Relief along 

the failure scar ranges from about 15 ft to 30 ft. Slopes across the scarp vary from approximately 7° to 25°. 

Throughout the northern Gulf of Mexico continental slope region, many slope failures are covered with a 

surficial drape of Holocene-aged pelagic sediments (Doyle et al., 1992). This drape has accumulated since 

the rise in sea level at the end of the Pleistocene (i.e., 12,000 yrs B.P.). The drape is ubiquitous on the 

continental slope. The presence of this drape over the failure scar and its debris field would indicate the 

slump is an ancient feature thousands of years old. The lack of drape would indicate that the landslide is a 

relatively recent feature and slope stability is a concern for this area. The resolution of the 3-D data is not 

adequate to define the presence or absence of the Holocene pelagic drape in this area. Therefore, the age 

of the seafloor failures cannot not be assessed with confidence. 

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 692-B well location. These small branching 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 (Map KC692-B-3) shows normal or ambient amplitudes along the seabed at, 

and near, the proposed wellsite. 

Stratigraphy. Stratigraphic conditions are shown on Figures KC692-B-1 and KC692-B-2. The seafloor 

and near-surface sediments at the Proposed Wellsite KC 692-B are expected to be hemipelagic and 

pelagic clays and silty clays. In general, beneath the drape to 374 ft bml the sediments consist of clayprone run-out debris associated with the shallow slope failure approximately 100 ft to the west. The 

sediments from 374 ft bml to the limit of investigation (5,760 ft bml) are generally composed of hemipelagic 

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

are possible within the stratified turbidites and mass-transport deposits. 

Faults. No seafloor faults are expected to be penetrated by the Proposed Wellsite KC 692-B; however, 

there are several faults near the proposed surface location along the shallow salt ridge to the west (Figures 

KC692-B-1 and KC692-B-2). The closest seafloor fault to the proposed wellsite is approximately 2,800 ft to 

the west. The fault trends northwest-southeast and is downthrown to the east-northeast. 

A buried fault lies approximately 340 ft west of the proposed well (Figure KC692-B-1). This fault trends 

northeast-southwest and is downthrown to the southeast. No other distinct faults were mapped at the 

Proposed Wellsite KC 692-B; however, the stratigraphic units along the salt ridge to the west are likely to 

be highly fractured as a result of the past motion of the underlying shallow salt structure. Faults may exist 

at the proposed location 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 5,760 ft of sediment (Figures KC692-B-1 and KC692-B-2). The potential for shallow water flow at 

this well location is considered negligible to low (Figure KC692-B-2). 

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 692-B ranges 

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

the limit of investigation (5,760 ft bml), Map KC692-B-4 and Figure KC692-B-2. Various amplitude events 

31
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 4 

FORUM ENERGY TECHNOLOGIES, INC.

exist near the proposed well location within debris flow deposits between the seafloor and 374 ft bml 

(Map KC692-B-4). An increase in amplitude character within this unit likely represents a change in 

lithology within the debris flow sediments. There is a low potential for encountering shallow gas within this 

interval. A low potential for encountering shallow gas exists from Horizon 30 (1,251 ft bml) to the limit of 

investigation (5,760 ft bml). Low- to moderate-amplitude reflectors in places may indicate an increase in 

minor amounts of biogenic gas within possible thin sand seams within the turbidite and mass-transport 

deposits. 

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

sedimentary section from the seafloor to the limit of investigation (5,760 ft bml), Figure KC692-B-2. A low 

potential for encountering overpressured sands exists within the units from Horizon 10 (840 ft bml) to the 

limit of investigation (5,760 ft bml). Any sands encountered within the turbidite and mass-transport deposits 

within these units are expected to be thin seams and not likely to produce sustained flows. No nearby 

wells reported any shallow water flow conditions and Block KC 692 lies a significant distance downslope 

from any recognized regional sand-bearing units. Any thin sand seams or silty-sand layers encountered 

are not expected to be overpressured. 

Closing 

The Proposed Wellsite KC 692-B in Keathley Canyon Block 692 generally appears suitable for exploration 

drilling operations. Engineers should be aware of the 9.9° seafloor slope. 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 

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, 2011, Notice to lessees and operators of federal oil and gas leases and 

pipeline right-of-way holders on the outer continental shelf, revisions to the list of OCS lease blocks requiring 

archaeological resource surveys and reports: U. S. Department of the Interior, Bureau of Ocean Energy Management, 

Bureau of Safety and Environmental Enforcement, Gulf of Mexico OCS Region, NTL 2011-JOINT-G01. 

Bureau of Ocean Energy Management, 2012, ASCII data files, published on the BOEM Gulf of Mexico Region 

homepage, <http://www.gomr.boem.gov/homepg/pubinfo/freeasci/freedesc.html>, accessed July, 2012. 

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. 

Doyle, E. H., Kaluza, M. J., and H. H. Roberts, 1992, Use of manned submersibles to investigate slumps in deep water 

Gulf of Mexico: Proceeding of the 5th International Conference of Civil Engineering in the Oceans, p. 770-782. 

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, 2012, Archaeological ROV assessment Moccasin area “B” Well, block 692, Keathley Canyon Protraction Area, 

U.S. Gulf of Mexico, February 2012, Geoscience Earth & Marine Services, Inc.®

, Report No. 0112-2040. 

32
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 5 

FORUM ENERGY TECHNOLOGIES, INC.

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, 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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35
36
37
10615 Shadow Wood Drive 

Suite 200 

Houston, Texas 77043 

(713) 468-1410 (o) 

(713) 468-1438 (f) 

www.gemsinc.com

Geoscience Earth & Marine Services, Inc. ® // 1 

FORUM ENERGY TECHNOLOGIES, INC.

July 10, 2012 Project No. 0412-2080 

Chevron U.S.A. Inc. 

1500 Louisiana 

Room 5717F 

Houston, Texas 77002 

Attention: Mr. Philip Von Dullen III 

Site Clearance Letter 

Proposed Wellsite KC 692-C 

Block 692 (OCS G-25801) 

Keathley Canyon Area, Gulf of Mexico 

Chevron U.S.A. Inc., (Chevron) plans to drill an exploration well in Block 692 of the Keathley Canyon (KC) 

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

of approximately 6,540 ft below the mudline (bml), at the Proposed Exploration Wellsite KC 692-C. 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 and within the archaeological ROV assessment (GEMS Report Nos. 

0109-1600 and 0112-2040; GEMS, 2009 and 2012 respectively). 

The surface location of the proposed KC 692-C wellsite lies in the central portion of KC 692. Chevron 

provided the following coordinates: 

Proposed Exploration Wellsite KC 692-C

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 15 North, U.S. ft 

Line 

Reference 

Block Calls 

KC 692 

X: 1,845,947 Latitude: 26o 17' 40.72243" N Inline: 14530 7,333 ft FEL 

Y: 9,541,656 Longitude: 92o 22' 20.90569" W Crossline: 5757 5,976 ft FSL 

Chevron plans to 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 No. KC692-C-1. Bathymetry Map 

• Map No. KC692-C-2. Seafloor Rendering 

• Map No. KC692-C-3. Seafloor Amplitude Rendering 

• Map No. KC692-C-4. Geologic Features Map 

• Figure KC692-C-1. Portions of Inline 14530 and Crossline 5757 Showing Conditions 

 Beneath Proposed Wellsite KC 692-C 

• Figure KC692-C-2. Tophole Prognosis Chart, Proposed Wellsite KC 692-C, Keathley 

 Canyon Area, Block 692 

 

38
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 2 

FORUM ENERGY TECHNOLOGIES, INC.

NTL Requirements

The following report complies with the Bureau of Ocean Energy Management (BOEM, formerly MMS) 

Notice to Lessees (NTL’s) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). The operator will be required 

to follow NTL’s 2008-G04 and -G06 with respect to an ROV monitoring survey as well as pre- and postspud ROV visual inspection surveys (MMS, 2008b and 2008c). 

The Federal lease Block KC 692 is not considered archaeologically significant (BOEM, 2011); 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. GEMS submitted an archaeological ROV assessment for Keathley Canyon Block 692 

to Chevron in March 2012 (GEMS, 2012). This archaeological ROV assessment satisfies the BOEMRE 

requirement. 

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 BOEM, 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 location. 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 692, Proposed Wellsite KC 692-C 

Man-Made Features

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

4.0 miles south-southwest of the proposed well location. The KC 736 #1 well is permanently abandoned. 

There are no existing pipelines, cables, or platforms within KC 692 or in the immediate surrounding blocks 

(BOEM, 2012). 

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0.3

0.4

0.5

0.6

0.7

0.8

0.9

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0 10 20 30 40 50 60 70 80 90 100

Power (Amp2

)

Frequency (Hz)

POWER SPECTRUM

39
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 3 

FORUM ENERGY TECHNOLOGIES, INC.

Wellsite Conditions 

The surface location is clear of any constraining geologic conditions within a 2,000-ft 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 -6,710 ft

(Map KC692-C-1). The seafloor at the proposed wellsite is slightly irregular, and dips to the east-northeast 

at about 3.5°. The ROV data shows little perceptible relief along the proposed well location. The nearsurface sediments are expected to be normally consolidated clays forming a drape over the area. The 

Proposed Wellsite KC 692-C is situated along the flank of an expansive shallow salt ridge. The seafloor 

along the salt ridge is irregular as a result of numerous fault scarps, seafloor failures, and the deformation 

of the shallow overburden by the underlying salt (Map KC692-C-2). 

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 692-C survey location. These small branching 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 (Map KC692-C-3) shows normal or ambient amplitudes along the seabed at, 

and near, the proposed wellsite. 

Stratigraphy. Stratigraphic conditions are shown on Figures KC692-C-1 and KC692-C-2. The seafloor at 

and near-surface sediments at the Proposed Wellsite KC 692-C are expected to be hemipelagic and 

pelagic clays and silty clays. In general, the sediments between the seafloor and the limit of investigation 

(6,540 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 the stratified turbidites and mass-transport 

deposits. 

Faults. Several seafloor and buried faults exist near the proposed well location along the shallow salt 

ridge. A vertical borehole will intersect a seafloor fault at approximately 649 ft bml (Figures KC692-C-1 and 

KC692-C-2). The fault is located about 600 ft to the southwest, trends northwest-southeast, and is 

downthrown to the northeast. The fault exhibits approximately 5 ft of relief. The offset of the seafloor 

implies that motion along the fault is probably still occurring, but at rates analogous to soil creep. 

A vertical borehole will intersect two buried faults at 357 ft and 1,042 ft bml (Figures KC692-C-1 and 

KC692-C-2). These faults trend northwest-southeast and are downthrown to the northeast. No other 

distinct faults were mapped at the Proposed Wellsite KC 692-C; however, the stratigraphic units along the 

salt ridge are likely to be highly fractured as a result of the past motion of the underlying shallow salt 

structure. Faults may exist at the proposed location 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 6,540 ft of sediment (Figures KC692-C-1 and KC692-C-2). The potential for shallow water flow at 

this well location is considered negligible to low (Figure KC692-C-2). 

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 692-C ranges 

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

the limit of investigation (6,540 ft bml), Map KC692-C-4 and Figure KC692-C-2. A low potential for 

encountering shallow gas exists from 1,739 ft bml to the limit of investigation (6,540 ft bml). Low- to 

moderate-amplitude reflectors in places may indicate an increase in minor amounts of biogenic gas within 

possible thin sand seams within the turbidite and mass-transport deposits. There is a negligible potential 

for encountering shallow gas between the seafloor and 1,739 ft bml. 

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

sedimentary section from the seafloor to the limit of investigation (6,540 ft bml), Figure KC692-C-2. A low 

potential for encountering overpressured sands exists within the units from 1,042 ft bml to the limit of 

investigation (6,540 ft bml). Any sands encountered within the turbidite and mass-transport deposits within 

these units are expected to be thin seams and not likely to produce sustained flows. No nearby wells 

reported any shallow water flow conditions and Block KC 692 lies a significant distance downslope from 

any recognized regional sand-bearing units. Any thin sand seams or silty-sand layers encountered are not 

expected to be overpressured. 

40
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 4 

FORUM ENERGY TECHNOLOGIES, INC.

Closing 

The Proposed Wellsite KC 692-C in Keathley Canyon Block 692 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 

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, 2011, Notice to lessees and operators of federal oil and gas leases and 

pipeline right-of-way holders on the outer continental shelf, revisions to the list of OCS lease blocks requiring 

archaeological resource surveys and reports: U. S. Department of the Interior, Bureau of Ocean Energy Management, 

Bureau of Safety and Environmental Enforcement, Gulf of Mexico OCS Region, NTL 2011-JOINT-G01. 

Bureau of Ocean Energy Management, 2012, ASCII data files, published on the BOEM Gulf of Mexico Region 

homepage, <http://www.gomr.boem.gov/homepg/pubinfo/freeasci/freedesc.html>, accessed July, 2012. 

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, 2012, Archaeological ROV assessment Moccasin area “C” Well, block 692, Keathley Canyon Protraction Area, 

U.S. Gulf of Mexico, February 2012, Geoscience Earth & Marine Services, Inc.®

, Report No. 0112-2040. 

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, 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. 

41
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43
44
45
10615 Shadow Wood Drive 

Suite 200 

Houston, Texas 77043 

(713) 468-1410 (o) 

(713) 468-1438 (f) 

www.gemsinc.com

Geoscience Earth & Marine Services, Inc. ® // 1 

FORUM ENERGY TECHNOLOGIES, INC.

July 10, 2012 Project No. 0412-2080 

Chevron U.S.A. Inc. 

1500 Louisiana 

Room 5717F 

Houston, Texas 77002 

Attention: Mr. Philip Von Dullen III 

Site Clearance Letter 

Proposed Wellsite KC 692-D 

Block 692 (OCS G-25801) 

Keathley Canyon Area, Gulf of Mexico 

Chevron U.S.A. Inc., (Chevron) plans to drill an exploration well in Block 692 of the Keathley Canyon (KC) 

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

of approximately 6,285 ft below the mudline (bml), at the Proposed Exploration Wellsite KC 692-D. 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 and within the archaeological ROV assessment (GEMS Report Nos. 

0109-1600 and 0112-2040; GEMS, 2009 and 2012 respectively). 

The surface location of the proposed KC 692-D wellsite lies in the southeastern portion of KC 692. Chevron 

provided the following coordinates: 

Proposed Exploration Wellsite KC 692-D

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 15 North, U.S. ft 

Line 

Reference 

Block Calls 

KC 692 

X: 1,848,043 Latitude: 26o 17' 20.01312" N Inline: 14375 5,237 ft FEL 

Y: 9,539,576 Longitude: 92o 21' 57.98059" W Crossline: 5808 3,896 ft FSL 

Chevron plans to 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 No. KC692-D-1. Bathymetry Map 

• Map No. KC692-D-2. Seafloor Rendering 

• Map No. KC692-D-3. Seafloor Amplitude Rendering 

• Map No. KC692-D-4. Geologic Features Map 

• Figure KC692-D-1. Portions of Inline 14375 and Crossline 5808 Showing Conditions 

 Beneath Proposed Wellsite KC 692-D 

• Figure KC692-D-2. Tophole Prognosis Chart, Proposed Wellsite KC 692-D, Keathley 

 Canyon Area, Block 692 

 

46
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 2 

FORUM ENERGY TECHNOLOGIES, INC.

NTL Requirements

The following report complies with the Bureau of Ocean Energy Management (BOEM, formerly MMS) 

Notice to Lessees (NTL’s) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). The operator will be required 

to follow NTL’s 2008-G04 and -G06 with respect to an ROV monitoring survey as well as pre- and postspud ROV visual inspection surveys (MMS, 2008b and 2008c). 

The Federal lease Block KC 692 is not considered archaeologically significant (BOEM, 2011); 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. GEMS submitted an archaeological ROV assessment for Keathley Canyon Block 692 

to Chevron in March 2012 (GEMS, 2012). This archaeological ROV assessment satisfies the BOEMRE 

requirement. 

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 BOEM, 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 location. 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 692, Proposed Wellsite KC 692-D 

Man-Made Features

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

3.7 miles southwest of the proposed well location. The KC 736 #1 well is permanently abandoned. There 

are no existing pipelines, cables, or platforms within KC 692 or in the immediate surrounding blocks 

(BOEM, 2012). 

0

0.1

0.2

0.3

0.4

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0.8

0.9

1

0 10 20 30 40 50 60 70 80 90 100

Power (Amp2

)

Frequency (Hz)

POWER SPECTRUM

47
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 3 

FORUM ENERGY TECHNOLOGIES, INC.

Wellsite Conditions 

The surface location is clear of any constraining geologic conditions within a 2,000-ft 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 -6,848 ft

(Map KC692-D-1). The seafloor at the proposed wellsite is generally smooth, and dips to the eastnortheast at about 8.6°. The ROV data confirms a relatively smooth mud bottom across the proposed well 

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

the area. The Proposed Wellsite KC 692-D is situated along the flank of a broad intraslope basin named 

Chalmette Basin. An expansive shallow salt ridge lies approximately 500 ft west-southwest of the 

proposed well location. The seafloor along the salt ridge is irregular as a result of numerous fault scarps, 

seafloor failures, and the deformation of the shallow overburden by the underlying salt (Map KC692-D-2). 

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 692-D survey location. These small branching 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 (Map KC692-D-3) shows normal or ambient amplitudes along the seabed at, 

and near, the proposed wellsite. 

Stratigraphy. Stratigraphic conditions are shown on Figures KC692-D-1 and KC692-D-2. The seafloor at 

and near-surface sediments at the Proposed Wellsite KC 692-D are expected to be hemipelagic and 

pelagic clays and silty clays. In general, the sediments between the seafloor and the limit of investigation 

(6,285 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 the stratified turbidites and mass-transport 

deposits. 

Faults. No seafloor faults are expected to be penetrated by the Proposed Wellsite KC 692-D; however, 

there are several faults near the proposed surface location along the shallow salt ridge to the west (Figures 

KC692-D-1 and KC692-D-2). The closest seafloor fault to the proposed wellsite is approximately 1,475 ft 

to the northwest. The fault trends northwest-southeast and is downthrown to the east-northeast. 

A vertical borehole will intersect three buried faults at 571 ft, 1,062 ft, and 1,724 ft bml (Figures KC692-D-1 

and KC692-D-2). These faults trend northwest-southeast and are downthrown to the northeast. No other 

distinct faults were mapped at the Proposed Wellsite KC 692-D; however, the stratigraphic units along the 

salt ridge to the west are likely to be highly fractured as a result of the past motion of the underlying shallow 

salt structure. Faults may exist at the proposed location 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 6,285 ft of sediment (Figures KC692-D-1 and KC692-D-2). The potential for shallow water flow at 

this well location is considered negligible to low (Figure KC692-D-2). 

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 692-D ranges 

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

the limit of investigation (6,285 ft bml), Map KC692-D-4 and Figure KC692-D-2. A low potential for 

encountering shallow gas exists from 2,089 ft bml to the limit of investigation (6,285 ft bml). Low- to 

moderate-amplitude reflectors in places may indicate an increase in minor amounts of biogenic gas within 

possible thin sand seams within the turbidite and mass-transport deposits. There is a negligible potential 

for encountering shallow gas between the seafloor and 2,089 ft bml. 

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

sedimentary section from the seafloor to the limit of investigation (6,285 ft bml), Figure KC692-D-2. A low 

potential for encountering overpressured sands exists within the units from 1,062 ft bml to the limit of 

investigation (6,285 ft bml). Any sands encountered within the turbidite and mass-transport deposits within 

these units are expected to be thin seams and not likely to produce sustained flows. No nearby wells 

reported any shallow water flow conditions and Block KC 692 lies a significant distance downslope from 

any recognized regional sand-bearing units. Any thin sand seams or silty-sand layers encountered are not 

expected to be overpressured. 

48
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 4 

FORUM ENERGY TECHNOLOGIES, INC.

Closing 

The Proposed Wellsite KC 692-D in Keathley Canyon Block 692 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 

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, 2011, Notice to lessees and operators of federal oil and gas leases and 

pipeline right-of-way holders on the outer continental shelf, revisions to the list of OCS lease blocks requiring 

archaeological resource surveys and reports: U. S. Department of the Interior, Bureau of Ocean Energy Management, 

Bureau of Safety and Environmental Enforcement, Gulf of Mexico OCS Region, NTL 2011-JOINT-G01. 

Bureau of Ocean Energy Management, 2012, ASCII data files, published on the BOEM Gulf of Mexico Region 

homepage, <http://www.gomr.boem.gov/homepg/pubinfo/freeasci/freedesc.html>, accessed July, 2012. 

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, 2012, Archaeological ROV assessment Moccasin area “D” Well, block 692, Keathley Canyon Protraction Area, 

U.S. Gulf of Mexico, February 2012, Geoscience Earth & Marine Services, Inc.®

, Report No. 0112-2040. 

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, 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. 

49
50
51
52
53
10615 Shadow Wood Drive 

Suite 200 

Houston, Texas 77043 

(713) 468-1410 (o) 

(713) 468-1438 (f) 

www.gemsinc.com

Geoscience Earth & Marine Services, Inc. ® // 1 

FORUM ENERGY TECHNOLOGIES, INC.

July 10, 2012 Project No. 0412-2080 

Chevron U.S.A. Inc. 

1500 Louisiana 

Room 5717F 

Houston, Texas 77002 

Attention: Mr. Philip Von Dullen III 

Site Clearance Letter 

Proposed Wellsite KC 692-E 

Block 692 (OCS G-25801) 

Keathley Canyon Area, Gulf of Mexico 

Chevron U.S.A. Inc., (Chevron) plans to drill an exploration well in Block 692 of the Keathley Canyon (KC) 

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

of approximately 5,528 ft below the mudline (bml), at the Proposed Exploration Wellsite KC 692-E. 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 and within the archaeological ROV assessment (GEMS Report Nos. 

0109-1600 and 0112-2040; GEMS, 2009 and 2012 respectively). 

The surface location of the proposed KC 692-E wellsite lies in the southeastern portion of KC 692. Chevron 

provided the following coordinates: 

Proposed Exploration Wellsite KC 692-E

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 15 North, U.S. ft 

Line 

Reference 

Block Calls 

KC 692 

X: 1,850,412 Latitude: 26o 17' 15.72631" N Inline: 14340 2,868 ft FEL 

Y: 9,539,155 Longitude: 92o 21' 31.96715" W Crossline: 5866 3,475 ft FSL 

Chevron plans to 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 No. KC692-E-1. Bathymetry Map 

• Map No. KC692-E-2. Seafloor Rendering 

• Map No. KC692-E-3. Seafloor Amplitude Rendering 

• Map No. KC692-E-4. Geologic Features Map 

• Figure KC692-E-1. Portions of Inline 14340 and Crossline 5866 Showing Conditions 

 Beneath Proposed Wellsite KC 692-E 

• Figure KC692-E-2. Tophole Prognosis Chart, Proposed Wellsite KC 692-E, Keathley 

 Canyon Area, Block 692 

 

54
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 2 

FORUM ENERGY TECHNOLOGIES, INC.

NTL Requirements

The following report complies with the Bureau of Ocean Energy Management (BOEM, formerly MMS) 

Notice to Lessees (NTL’s) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). The operator will be required 

to follow NTL’s 2008-G04 and -G06 with respect to an ROV monitoring survey as well as pre- and postspud ROV visual inspection surveys (MMS, 2008b and 2008c). 

The Federal lease Block KC 692 is not considered archaeologically significant (BOEM, 2011); 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. GEMS submitted an archaeological ROV assessment for Keathley Canyon Block 692 

to Chevron in March 2012 (GEMS, 2012). This archaeological ROV assessment satisfies the BOEMRE 

requirement. 

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 BOEM, 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 location. 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 692, Proposed Wellsite KC 692-E 

Man-Made Features

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

3.7 miles southwest of the proposed well location. The KC 736 #1 well is permanently abandoned. There 

are no existing pipelines, cables, or platforms within KC 692 or in the immediate surrounding blocks 

(BOEM, 2012). 

0

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)

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POWER SPECTRUM

55
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 3 

FORUM ENERGY TECHNOLOGIES, INC.

Wellsite Conditions 

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

proposed wellsite. 

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

drilling at the proposed wellsite location. The water depth at the proposed surface location is approximately 

-7,251 ft (Map KC692-E-1). The seafloor at the proposed wellsite is generally smooth, and dips to the eastnortheast at a fairly steep inclination of 11.9°. The ROV data confirms a relatively smooth mud bottom 

across the proposed well location. The near-surface sediments are expected to be normally consolidated 

clays forming a drape over the area. The Proposed Wellsite KC 692-E is situated along the flank of a 

broad intraslope basin named Chalmette Basin. An expansive shallow salt ridge lies approximately 2,200 ft 

west-southwest of the proposed well location. The seafloor along the salt ridge is irregular as a result of 

numerous fault scarps, seafloor failures, and the deformation of the shallow overburden by the underlying 

salt (Map KC692-E-2). 

A shallow slope failure scarp lies approximately 2,000 ft to the west of the proposed location. Relief along 

the failure scar ranges from about 15 ft to 30 ft. Slopes across the scarp vary from approximately 7° to 25°. 

Throughout the northern Gulf of Mexico continental slope region, many slope failures are covered with a 

surficial drape of Holocene-aged pelagic sediments (Doyle et al., 1992). This drape has accumulated since 

the rise in sea level at the end of the Pleistocene (i.e., 12,000 yrs B.P.). The drape is ubiquitous on the 

continental slope. The presence of this drape over the failure scar and its debris field would indicate the 

slump is an ancient feature thousands of years old. The lack of drape would indicate that the landslide is a 

relatively recent feature and slope stability is a concern for this area. The resolution of the 3-D data is not 

adequate to define the presence or absence of the Holocene pelagic drape in this area. Therefore, the age 

of the seafloor failures cannot not be assessed with confidence. 

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 692-E survey location. These small branching 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 (Map KC692-E-3) shows normal or ambient amplitudes along the seabed at, 

and near, the proposed wellsite. 

Stratigraphy. Stratigraphic conditions are shown on Figures KC692-E-1 and KC692-E-2. The seafloor 

and near-surface sediments at the Proposed Wellsite KC 692-E are expected to be hemipelagic and 

pelagic clays and silty clays. In general, the sediments between the seafloor 271 ft bml consist of clayprone run-out debris associated with the shallow slope failure approximately 2,000 ft to the west. The 

sediments from 271 ft bml to the limit of investigation (5,528 ft bml) is generally composed of hemipelagic 

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

are possible within the stratified turbidites and mass-transport deposits. 

Faults. No seafloor faults are expected to be penetrated by the Proposed Wellsite KC 692-E; however, 

there are several faults near the proposed surface location along the shallow salt ridge (Figures KC692-E-1 

and KC692-E-2). The closest seafloor fault to the proposed wellsite is approximately 3,000 ft to the west. 

The fault trends northwest-southeast and is downthrown to the east-northeast. 

No other distinct faults were mapped at the Proposed Wellsite KC 692-E; however, the stratigraphic units 

along the salt ridge to the west are likely to be highly fractured as a result of the past motion of the 

underlying shallow salt structure. Faults may exist at the proposed location 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 5,528 ft of sediment (Figures KC692-E-1 and KC692-E-2). The potential for shallow water flow at 

this well location is considered negligible to low (Figure KC692-E-2). 

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 692-E ranges 

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

the limit of investigation (5,528 ft bml), Map KC692-E-4 and Figure KC692-E-2. Various amplitude events 

exist near the proposed well location within debris flow deposits between the seafloor and 271 ft bml 

56
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 4 

FORUM ENERGY TECHNOLOGIES, INC.

(Map KC692-E-4). An increase in amplitude character within this unit likely represents a change in 

lithology within the debris flow sediments. There is a low potential for encountering shallow gas within this 

interval. A low potential for encountering shallow gas exists from Horizon 30 (1,792 ft bml) to the limit of 

investigation (5,528 ft bml). Low- to moderate-amplitude reflectors in places may indicate an increase in 

minor amounts of biogenic gas within possible thin sand seams within the turbidite and mass-transport 

deposits. 

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

sedimentary section from the seafloor to the limit of investigation (5,528 ft bml), Figure KC692-E-2. A low 

potential for encountering overpressured sands exists within the units from Horizon 10 (924 ft bml) to the 

limit of investigation (5,528 ft bml). Any sands encountered within the turbidite and mass-transport deposits 

within these units are expected to be thin seams and not likely to produce sustained flows. No nearby 

wells reported any shallow water flow conditions and Block KC 692 lies a significant distance downslope 

from any recognized regional sand-bearing units. Any thin sand seams or silty-sand layers encountered 

are not expected to be overpressured. 

Closing 

The Proposed Wellsite KC 692-E in Keathley Canyon Block 692 generally appears suitable for exploration 

drilling operations. Engineers should be aware of the 11.9° seafloor slope. 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 

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, 2011, Notice to lessees and operators of federal oil and gas leases and 

pipeline right-of-way holders on the outer continental shelf, revisions to the list of OCS lease blocks requiring 

archaeological resource surveys and reports: U. S. Department of the Interior, Bureau of Ocean Energy Management, 

Bureau of Safety and Environmental Enforcement, Gulf of Mexico OCS Region, NTL 2011-JOINT-G01. 

Bureau of Ocean Energy Management, 2012, ASCII data files, published on the BOEM Gulf of Mexico Region 

homepage, <http://www.gomr.boem.gov/homepg/pubinfo/freeasci/freedesc.html>, accessed July, 2012. 

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. 

Doyle, E. H., Kaluza, M. J., and H. H. Roberts, 1992, Use of manned submersibles to investigate slumps in deep water 

Gulf of Mexico: Proceeding of the 5th International Conference of Civil Engineering in the Oceans, p. 770-782. 

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, 2012, Archaeological ROV assessment Moccasin area “E” Well, block 692, Keathley Canyon Protraction Area, 

U.S. Gulf of Mexico, February 2012, Geoscience Earth & Marine Services, Inc.®, Report No. 0112-2040. 

57
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 5 

FORUM ENERGY TECHNOLOGIES, INC.

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, 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. 

58
59
60
61
62
10615 Shadow Wood Drive 

Suite 200 

Houston, Texas 77043 

(713) 468-1410 (o) 

(713) 468-1438 (f) 

www.gemsinc.com

Geoscience Earth & Marine Services, Inc. ® // 1 

FORUM ENERGY TECHNOLOGIES, INC.

July 10, 2012 Project No. 0412-2080 

Chevron U.S.A. Inc. 

1500 Louisiana 

Room 5717F 

Houston, Texas 77002 

Attention: Mr. Philip Von Dullen III 

Site Clearance Letter 

Proposed Wellsite KC 692-F 

Block 692 (OCS G-25801) 

Keathley Canyon Area, Gulf of Mexico 

Chevron U.S.A. Inc., (Chevron) plans to drill an exploration well in Block 692 of the Keathley Canyon (KC) 

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

of approximately 5,299 ft below the mudline (bml), at the Proposed Exploration Wellsite KC 692-F. 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 and within the archaeological ROV assessment (GEMS Report Nos. 

0109-1600 and 0112-2040; GEMS, 2009 and 2012 respectively). 

The surface location of the proposed KC 692-F wellsite lies in the southeastern portion of KC 692. Chevron 

provided the following coordinates: 

Proposed Exploration Wellsite KC 692-F

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 15 North, U.S. ft 

Line 

Reference 

Block Calls 

KC 692 

X: 1,851,302 Latitude: 26o 17' 05.03174" N Inline: 14260 1,978 ft FEL 

Y: 9,538,080 Longitude: 92o 21' 22.24456" W Crossline: 5887 2,400 ft FSL 

Chevron plans to 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 No. KC692-F-1. Bathymetry Map 

• Map No. KC692-F-2. Seafloor Rendering 

• Map No. KC692-F-3. Seafloor Amplitude Rendering 

• Map No. KC692-F-4. Geologic Features Map 

• Figure KC692-F-1. Portions of Inline 14260 and Crossline 5887 Showing Conditions 

 Beneath Proposed Wellsite KC 692-F 

• Figure KC692-F-2. Tophole Prognosis Chart, Proposed Wellsite KC 692-F, Keathley 

 Canyon Area, Block 692 

 

63
Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 2 

FORUM ENERGY TECHNOLOGIES, INC.

NTL Requirements

The following report complies with the Bureau of Ocean Energy Management (BOEM, formerly MMS) 

Notice to Lessees (NTL’s) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). The operator will be required 

to follow NTL’s 2008-G04 and -G06 with respect to an ROV monitoring survey as well as pre- and postspud ROV visual inspection surveys (MMS, 2008b and 2008c). 

The Federal lease Block KC 692 is not considered archaeologically significant (BOEM, 2011); 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. GEMS submitted an archaeological ROV assessment for Keathley Canyon Block 692 

to Chevron in March 2012 (GEMS, 2012). This archaeological ROV assessment satisfies the BOEMRE 

requirement. 

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 BOEM, 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 location. 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 692, Proposed Wellsite KC 692-F 

Man-Made Features

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

3.6 miles southwest of the proposed well location. The KC 736 #1 well is permanently abandoned. There 

are no existing pipelines, cables, or platforms within KC 692 or in the immediate surrounding blocks 

(BOEM, 2012). 

 

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 10 20 30 40 50 60 70 80 90 100

Power (Amp2

)

Frequency (Hz)

POWER SPECTRUM

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Geoscience Earth & Marine Services, Inc. ® // 3 

FORUM ENERGY TECHNOLOGIES, INC.

Wellsite Conditions 

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

proposed wellsite. 

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

drilling at the proposed wellsite location. The water depth at the proposed surface location is approximately 

-7,386 ft (Map KC692-F-1). The seafloor at the proposed wellsite is generally smooth, and dips to the eastnortheast at a fairly steep inclination of 11.3°. The ROV data confirms a relatively smooth mud bottom 

across the proposed well location. The near-surface sediments are expected to be normally consolidated 

clays forming a drape over the area. The Proposed Wellsite KC 692-F is situated along the flank of a 

broad intraslope basin named Chalmette Basin. An expansive shallow salt ridge lies approximately 2,720 ft 

southwest of the proposed well location. The seafloor along the salt ridge is irregular as a result of 

numerous fault scarps, seafloor failures, and the deformation of the shallow overburden by the underlying 

salt (Map KC692-F-2). 

A shallow slope failure scarp lies approximately 2,500 ft to the west of the proposed location. Relief along 

the failure scar ranges from about 15 ft to 30 ft. Slopes across the scarp vary from approximately 7° to 25°. 

Throughout the northern Gulf of Mexico continental slope region, many slope failures are covered with a 

surficial drape of Holocene-aged pelagic sediments (Doyle et al., 1992). This drape has accumulated since 

the rise in sea level at the end of the Pleistocene (i.e., 12,000 yrs B.P.). The drape is ubiquitous on the 

continental slope. The presence of this drape over the failure scar and its debris field would indicate the 

slump is an ancient feature thousands of years old. The lack of drape would indicate that the landslide is a 

relatively recent feature and slope stability is a concern for this area. The resolution of the 3-D data is not 

adequate to define the presence or absence of the Holocene pelagic drape in this area. Therefore, the age 

of the seafloor failures cannot not be assessed with confidence. 

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 692-F survey location. These small branching 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 (Map KC692-F-3) shows normal or ambient amplitudes along the seabed at 

the proposed wellsite. An elevated amplitude event occurs approximately 1,800 ft southeast of the 

proposed location. This event likely corresponds to a change in lithology within near-surface debris flow 

deposits and does not represent fluid/gas expulsion or carbonate hardgrounds. 

Stratigraphy. Stratigraphic conditions are shown on Figures KC692-F-1 and KC692-F-2. The seafloor at 

and near-surface sediments at the Proposed Wellsite KC 692-F are expected to be hemipelagic and 

pelagic clays and silty clays. In general, the sediments between the seafloor 334 ft bml consist of clayprone run-out debris associated with the shallow slope failure approximately 2,500 ft to the west. The 

sediments from 334 ft bml to the limit of investigation (5,299 ft bml) generally consist of hemipelagic clays 

and clay-rich turbidite deposits interlayered in places with thin debris flow deposits. Thin sand layers are 

possible within the stratified turbidites and mass-transport deposits. 

Faults. No seafloor faults are expected to be penetrated by the Proposed Wellsite KC 692-F; however, 

there are several faults near the proposed surface location along the shallow salt ridge to the west (Figures 

KC692-F-1 and KC692-F-2). The closest seafloor fault to the proposed wellsite is approximately 4,300 ft to 

the west. The fault trends northwest-southeast and is downthrown to the east-northeast. 

A buried fault lies approximately 2,215 ft west of the proposed well location (Figures KC692-F-1 and 

KC692-F-2). This fault trends northwest-southeast and is downthrown to the northeast. No other distinct 

faults were mapped at the Proposed Wellsite KC 692-F; however, the stratigraphic units along the salt 

ridge to the west are likely to be highly fractured as a result of the past motion of the underlying shallow salt 

structure. Faults may exist at the proposed location 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 5,299 ft of sediment (Figures KC692-F-1 and KC692-F-2). The potential for shallow water flow at 

this well location is considered negligible to low (Figure KC692-F-2). 

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Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 4 

FORUM ENERGY TECHNOLOGIES, INC.

Shallow Gas. The potential for encountering shallow gas at the Proposed Wellsite KC 692-F ranges 

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

the limit of investigation (5,299 ft bml), Map KC692-F-4 and Figure KC692-F-2. Various amplitude events 

exist near the proposed well location at the seafloor and between the seafloor and 334 ft bml within the 

debris flow deposits (Map KC692-F-4). An increase in amplitude character within this unit likely represents 

a change in lithology within the debris flow sediments. There is a low potential for encountering shallow 

gas within this interval. A low potential for encountering shallow gas exists from Horizon 30 (2,284 ft bml) 

to the limit of investigation (5,299 ft bml). Low- to moderate-amplitude reflectors in places may indicate an 

increase in minor amounts of biogenic gas within possible thin sand seams within the turbidite and masstransport deposits. 

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

sedimentary section from the seafloor to the limit of investigation (5,299 ft bml), Figure KC692-F-2. A low 

potential for encountering overpressured sands exists within the units from Horizon 10 (999 ft bml) to the 

limit of investigation (5,299 ft bml). Any sands encountered within the turbidite and mass-transport deposits 

within these units are expected to be thin seams and not likely to produce sustained flows. No nearby 

wells reported any shallow water flow conditions and Block KC 692 lies a significant distance downslope 

from any recognized regional sand-bearing units. Any thin sand seams or silty-sand layers encountered 

are not expected to be overpressured. 

Closing 

The Proposed Wellsite KC 692-F in Keathley Canyon Block 692 appears suitable for exploration drilling 

operations. Engineers should be aware of the approximate 11.3° seafloor slope. 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 

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, 2011, Notice to lessees and operators of federal oil and gas leases and 

pipeline right-of-way holders on the outer continental shelf, revisions to the list of OCS lease blocks requiring 

archaeological resource surveys and reports: U. S. Department of the Interior, Bureau of Ocean Energy Management, 

Bureau of Safety and Environmental Enforcement, Gulf of Mexico OCS Region, NTL 2011-JOINT-G01. 

Bureau of Ocean Energy Management, 2012, ASCII data files, published on the BOEM Gulf of Mexico Region 

homepage, <http://www.gomr.boem.gov/homepg/pubinfo/freeasci/freedesc.html>, accessed July, 2012. 

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. 

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Project No. 0412-2080 

Chevron U.S.A. Inc. // July 10, 2012

Geoscience Earth & Marine Services, Inc. ® // 5 

FORUM ENERGY TECHNOLOGIES, INC.

Doyle, E. H., Kaluza, M. J., and H. H. Roberts, 1992, Use of manned submersibles to investigate slumps in deep water 

Gulf of Mexico: Proceeding of the 5th International Conference of Civil Engineering in the Oceans, p. 770-782. 

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, 2012, Archaeological ROV assessment Moccasin area “F” Well, block 692, Keathley Canyon Protraction Area, 

U.S. Gulf of Mexico, February 2012, Geoscience Earth & Marine Services, Inc.®, Report No. 0112-2040. 

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, 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. 

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Chevron U.S.A. Inc. Initial Exploration Plan 

Keathley Canyon Block 692 Public Information

(g) HIGH RESOLUTION SEISMIC LINES

The high resolution seismic lines are being replaced by 3-D seismic survey data.

(h) STRATIGRAPHIC COLUMN

Proprietary Information

(i) TIME vs. DEPTH TABLE

Due to adequate well control in the area, Chevron feels that a time vs. depth table is not required.

ATTACHMENTS TO SECTION C (Proprietary Information)

• C-1 - Depth Structure Contour Map

• C- 2, 4, 6, 8, 10 – Schematic Cross Section

• C- 3, 5, 7, 9, 11 – Interpreted 3- D Seismic Line

• C-12 - Stratigraphic Column

PROPRIETARY ENCLOSURE TO PLAN

• “Site Clearance Letters, Proposed Wellsites KC 692-A(KC 736 A3), B, C, D, E, and F, Geoscience Earth & 

Marine Services, Inc. ®, July 10, 2012 (Project No. 0412-2080) (Two Hard Copies and Two Digital Copies)

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Chevron U.S.A. Inc. Initial Exploration Plan 

Keathley Canyon Block 692 Public Information

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 Hydrogen Sulfide has been produced or 

encountered in the closest wells to the area. Based on this evidence, Chevron requests that the area be classified as 

a zone where the absence of H2S has been confirmed.

(c) H2S CONTINGENCY PLAN

Should the Regional Supervisor not classify KC Block 692 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.

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