6866.0 34000.0 6866.0 34200.0 Line: T race: 25000 30000 1.400
1.500
1.600
1.700
1.800
1.900
2.000
2.100
2.200
2.300
2.400
2.500 Horizontal Distance (ft): Shallow W ater Flow and Gas Potential HIGH 0 1 2 3 0 = NEGLIGIBLE 1 = LOW 2 = MODERA

TE 3 = HIGH NEGLIGIBLE



### Figure GC 867-B-2. T

ophole Prognosis Chart, Proposed W ellsite B, Green Canyon Block 867 Filename: 1 1 1924_fig_GC867-B-2.cdr Project No. 041 1-1924 3-D Seismic Section Through Proposed W ellsite B X = 2,473,150 FT; Y

= 9,851,000 FT Crossline 34079 at Inline 6866 NW SE

Inline 6866 GC

823 PROPOSED WELLSITE BTWO-WAYTRAVELTIME (SEC) GC

867

SEAFLOOR W ater Flow Gas

HORIZON 20

T OP OF SAL TUnit 2 1.741

1.775

1.903 -4,267 -4,357
-4,699 90

432 90

221 Seafloor Slopes at 3.9° South.

Lithology/Stratigraphy W A TER FLOW AND GAS POTENTIAL Horizon Horizon TWT (sec, bsl) Depth

(ft, bsl) Depth (ft, bml)Units Unit

(Interval) Thickness (ft)Unit 3 Potential Drilling Constraints

HORIZON 35 1.821 -4,478 21 1 121 V ery soft, pelagic drape at seafloor . Hemipelagic silty clays and thin mass-transport deposits. Alternating layers of hemipelagic silty clays with chaotic mass-transport deposits. Chaotic sequence created by salt movement. Mixture of silts and clays. Negligible potential for overpressured sands. Negligible potential for shallow gas. Low potential for overpressured sands. Low potential for shallow gas.

SAL T T op of salt Slopes at 17° to Southeast. GC 822Unit 1 Negligible potential for overpressured sands. Negligible potential for shallow gas.

TROUGH PEAK RELA TIVE AMPLITUDE10615 SHADOW WOOD DRIVE SUITE 200 HOUSTON, TEXAS 77043 Phone: (713) 468 - 1410

Fax: (713) 468 - 1438 E - mail: gems@gemsinc.com

- 1 - Proposed Well GC 867 - C May 20 , 2011 Project No. 0411 - 1924 Apache Deepwater, LLC 2000 W. Sam Houston Pkwy. South, Suite 1600 Houston , Texas 77042 - 3622 Attention: Mr. Joh n A. Worthen 

### Site Clearance Letter Proposed Wellsite GC 8 67 - C

Block 8 67 (OCS - G - 33858 ) Green Canyon Area Gulf of Mexico Apache Deepw ater, LLC ( Apache ) plans to drill an exploration well in Block 867 , of the Green Canyon Area ( GC ), Gulf of Mexico. This letter addresses specific seafloor and subsurface geologic conditions to a depth of approximately 532 ft below the mudline ( bml ) at the P roposed Wellsite GC 867 - C . The following discussion is based on findings provided within the main bod y of the geohazard report for Blocks 823 and 867 (GEMS Report No. 0411 - 1924). The surface location for proposed Wellsite GC 8 67 - C is in the northwes tern quadrant of GC 867 . Apache provided the following coordinates: Proposed Wellsite GC 8 67 - C Spheroid & Datum: Clarke 1866, NAD27 Projection: UTM Zone 1 5 North Line Reference Block Calls X : 2,47 4 , 46 0 ft Latitude: 27.1 210600440824 o N Inline 6 855 2,53 0 ft F N L Y: 9,8 49 , 95 0 ft Longitude: 90.4 355210825508 ° W Crossline 340 43 3 , 42 0 ft FWL Apache will drill this well using a moored vessel. An exact anchor pattern for the proposed well location is undetermined at this time. Maps GC 867 - C - 1 through GC 867 - C - 4 show an anchor radius representing a typical maximum length of chain and anchor on bottom is d isplayed at 10,000 ft from the proposed wellsite. A 1,000 ft buffer zoned beyond the limits of the anchor radius is also included, NTL 2009 - G40 (MMS, 2009a). 

### Attachments The maps and figures accompanying this letter have been extracted from the main repo rt’s original maps and 3 - D data volume and centered on the proposed well location. Map GC 867 - C - 1: Bathymetry Map Map GC 867 - C - 2: Seafloor Rendering Map GC 867 - C - 3: Seafloor Amplitude Rendering Map GC 867 - C - 4: Geologic Features Map Figure GC 867 - C - 1: Inline 6855 and Crossline 34043 Showing Condit ions Beneath Proposed Wellsite GC 867 - C Figure GC 867 - C - 2: Tophole Prog nosis Chart, Proposed Wellsite GC 867 - C , G reen Canyon Block 867Project No. 0411 - 1924

- 2 - Proposed Well GC 867 - C 

### NTL Requirements The following report complies with the Bureau of Ocean Energy Management, Regulation, and Enforcement (BOEMRE; formerly the MMS) Notice to Lessees (NTLs) 2008 - G04, 2008 - G05 and 2009 - G40 (MMS, 200 8a, 2008b, and 200 9 a ). The proposed wellsite will be required to follow NTL 2008 - G06 with respect to pre - and post - spud ROV visual inspection surveys (MMS, 2008 c ). Pursuant to the recently released Pre - Seabed Disturbance Survey Mitigation issued by BOEMRE, the 2005 - G07 NTL (MMS, 2005) does not apply to GC 867 in terms of high - probability , (MMS, 2008d) , but a n archaeological assessment of the data must be performed prior to any bottom disturbing activities (BOEMRE, 2011b) . According to NTL 2008 - G05 (MMS, 2008b), 3 - D seismic reflection data may be used for shallow hazard assessments. A power spectrum analysi s was conducted from the 3 - D seismic data cube provided by Apache 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, o ver a time interval from the seafloor to ~0.198 second below mudline, i.e., the salt/sediment interface. 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, Proposed Wellsite GC 867 - C 

### Man - Made Features There are existing wells in G C 867 and in surrounding blocks. The closest well to Proposed Wellsite GC 867 - C is the BP Exploration Inc. , GC 823 - 00 1 well approximately 5,800 ft to the northeast (Maps GC 867 - C - 1 through GC 867 - C - 4). 0 0.2 0.4 0.6 0.8

1 1.2

0 10 20 30 40 50 60 70 80 90 100Power (amp2)

Frequency (hrz) POWER SPECTRUM

GC 867 - CProject No. 0411 - 1924

- 3 - Proposed Well GC 867 - C Other wells near the surface location of the Proposed Wellsite GC 867 - C are the BP Exploration Inc. , GC 866 - 001 and GC 823 - 002 wells. These wells are approximately 6,570 ft west and 12,520 ft north - east, respectively, of the proposed site and lie within the proposed mooring pattern. Proposed Wellsite GC 867 - C and its anchors lie within the “Military Warning Zone W - 92”. Military warning zones typically do not have any imp act on exploration drilling operations or other oilfield activities. However, notifications to appropriate military commands need to be addressed by Apache (MMS, 2009b). Restrictions would only be enforced during military operations in the area or during an emergency. 

### Water Depth and Seafloor Conditions T he water depth at the proposed location is - 4 ,250 ft (Map GC 867 - C - 1). The seafloor at the proposed location is slightly irregular and dips to the south west at about 6.8  ̊. The proposed wellsite is locat ed along the eastern flank of a southeasterly trending, arcuate valley (Map GC 867 - C - 2). The valley represents a Pleistocene slump scar. The valley occurs along the eastern margin of an extensive topographic high. The topographic high is the seafloor ex pression of a shallow salt diapir. Water depths within the potential anchor mooring area range from about - 3,660 ft along a ridge line to the north to approximately - 4, 900 ft near the upper part of the Sigsbee Escarpment to the south and southeast (Map GC 867 - C - 1). The seafloor within the potential anchoring area varies from smooth and featureless to very irregular. The seafloor irregularities include narrow ridges and gullies, faults, and mounds. Seafloor gradient within the mooring pattern will avera ge from 1° to 5°. The highest seafloor gradients in the area are associated with fault escarpments. Gradients of over 20  ̊ are associated with fault scarps that occur primarily north and east of the proposed location . The upper part of the Sigsbee Escarp ment to the south will be marked by an increase in slope from 10° to around 20°. Near - surface soils along the Sigsbee Escarpment are likely to be highly overconsolidated and much stronger than typical slope soils. 

### Deepwater Benthic Communities The Seafloo r Amplitude Rendering based on the 3 - D data volume (Map GC 867 - C - 3) shows normal or ambient amplitude along the seabed, with no indication of any hard - bottom or fluid expulsion events within 2,000 ft of the proposed GC 867 - C location. Based on the renderi ngs and seismic profiles d eepwater benthic communities are not expected within 2,000 ft of the proposed GC 867 - C wellsite. Patches of high - amplitude seafloor returns occur approximately 4 , 900 ft to the southwest of the location. The patches are associat ed with seafloor faults. In addition, the base of a mud mound exists approximately 10,000 ft to the northwest ( GC 867 - Maps C - 1 through GC 867 - C - 4). These features have a high - potential for deepwater benthic communities. Therefore, anchors must avoid thes e features by at least 250 ft (MMS, 2009a). A number of seafloor faults occur within the proposed mooring pattern. The closest seafloor faults occur approximately 475 ft to the north. Except for the faults 4, 900 ft to the southwest, no high - amplitude ret urns occur along the seabed escarpments; therefore, prolific hydrocarbon seepage or carbonate hardgrounds are unlikely. 

### Stratigraphy Inline 6855 and Crossline 34043 are the closest 3 - D lines to the proposed GC 867 - C location (Figure GC 867 - C - 1 ). The Tophole Prognosis Chart (Figure GC 867 - C - 2 ) shows the inline annotated with calculated depths to the various horizons and predicted lithology of the sequences, along with their potential for shallow water flow and shallow gas. The 3 - D data volume was used to define the sedimentary section to a depth of approximately 532 ft ( Figures GC 867 - C - 1 and GC 867 - C - 2). The section was divided into three units or sequences (FigureProject No. 0411 - 1924

- 4 - Proposed Well GC 867 - C GC 867 - C - 1 ). The sequences represent variations in depositional environments and possible changes in soil strength and composition. The surficial unit, Unit 1 (Seafloor to Horizon 20 ), to approximately 9 2 ft bml, consists of a very soft pelagic drape underlain with hemipelagic silty clays and thin, mass - transport deposits . Very soft clays with high water content will likely exist at the seabed. However, the underlying section has be en uplifted and eroded. Beneath the thin (~10 ft) of pelagic drape firm to stiff, overconsolidated soils may be encountered. Unit 2 (Horizon 20 to H orizon 35) consists of bedded hemipelagic clays interbedde d with thin chaotic mass - transport deposits. The sediments will be mud - rich; however, some thin sand seams and pockets are possible. The combined thickness of Units 1 and 2 is approximately 277 ft (Figure GC 867 - C - 2 ). Unit 3 is a sequence bounded by Horizon 35 and the top of salt ( Figures GC 867 - C - 1 and GC 867 - C - 2). This chaotic interval, affected by shallow salt emplacement, is between 2 77 ft and 532 ft bml at the proposed location. Unit 3 wil l likely consist of a mixture of silts and clays and is approximately 2 55 ft thick. The top of salt is predicted to be 532 ft bml (~4, 782 ft bsl). The salt surface dips to t he southeast at approximately 18 °. 

### Faults No faults will be intersected by the well bore beneath proposed Wellsite GC 867 - C (Figure s GC 867 - C - 1 and GC 867 - C - 2 ). 

### Shallow Water Flow Unit 2 between Horizons 20 and 35 is possibly the regional “Red Unit” slope - fan sequence. However, the top of the unit is only 9 2 ft bml at proposed We llsite GC 867 - C (Figure GC 867 - C - 2). The entire unit is 185 ft thick. At this location, Unit 2 is an unlikely zone for overpressured sand layers. The existing GC 823 - 001 well is approximately 5,800 ft to the northeast of the proposed GC 867 - C wellsite. A “low” severity shallow water flow occurred in the GC 823 - 001 well at 1,715 ft bml ( - 5,840 ft bsl). Based on the reported depth the flow occurred in the lower portion of Unit 4 within a generally low amplitude interval of discontinuous to cha otic reflections. Unit 4 is not present beneath the GC 867 - C wellsite. The potential for overpressured sands at this location is low to negligible. 

### Shallow Gas The well path will not penetrate any high - amplitude events between the seafloor and the top o f salt (Figure GC 867 - C - 2). There is a negligible to low potential for shallow gas in this section. 

### Closing The seafloor and near - surface conditions at Proposed Wellsite GC 867 - C , Green Canyon Block 867 (OCS G - 33 858), appear suitable for exploration drilling operations. The existing wellsites and the potential benthic communities will need to be avoided by anchors supporting a drilling vessel at the proposed location. Engineers should be aware that the soils above salt may be stronger and more consolidated than typical slope sediments.Project No. 0411 - 1924

- 5 - Proposed Well GC 867 - C Sincerely, GEOSCIENCE EARTH & MARINE SERVICES, INC. ®

Thomas W. Neurauter Ph. D. Daniel Lanier Senior Marine Geologist Vice - President/Marine Geologist Attachments ( 4 Maps, 2 Figures) Distribution: Mr . John Worthen , Apache, Houston, TX. ( 6 ) References: Bureau of Ocean Energy Management and Enforcement, 2011a , ASCII Data Files, published on the BOEMRE Gulf of Mexico Region Homepage, <http://www.gomr.mms.gov/homepg/pubinfo/freea sci/freedesc.html>, accessed May , 20 11 . Bureau of Ocean Energy Management, Regulation, and Enforcement , 20 11b, Pre - Seabed Disturbance Survey Mitigation < http://www.gomr.boemre.gov/homepg/regulate/environ/archaeological/Conditional - Archaeological Mitigation .pdf >. Coffeen, J. A., 1978, Seismic exploration fundamentals: Tulsa, the Petroleum Publishing Co., p. 125. Minerals Management Service, 2005, 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, Archaeological resource surveys and reports: U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2005 - G07. Minerals Management Service, 2008a, Notice to lessees and operato rs 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 Se rvice, Gulf of Mexico, NTL 2008 - G04. Effective Date May 1, 2008. Minerals Management Service, 2008 b , 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 O CS region, Shallow hazards requirements: U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008 - G05. Minerals Management Service, 2008 c , Notice to lessees and operators of federal oil, gas, and sulphur leases in the outer c ontinental 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, 2008 d , 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 resourc e surveys and reports: U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008 - G20.Project No. 0411 - 1924

- 6 - Proposed Well GC 867 - C Minerals Management Service, 20 09a , Notice to lessees and operators of federal oil and gas leases in the outer continental shelf, Gulf of M exico OCS region, Deepwater benthic communities: U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 200 9 - G 4 0. Minerals Management Service, 2009b, Notice to lessees and operators of federal oil and gas leases and pipeline right of

- way holders on the outer continental shelf, Gulf of Mexico OCS region, Military Warning and Water Test Areas: U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2009 - G06. Effective Date April 22, 2009.6855.0 33800.0 6855.0 34000.0 6855.0 34200.0 Line: T race: 20000 25000 30000 35000 40000 45000 1.300 1.400 1.500 1.600 1.700 1.800 1.900 2.000 2.100 2.200 2.300 2.400 2.500 2.600 2.700 Horizontal Distance (ft):

6800.0 34043.0 7000.0 34043.0 Line: T race: 10000 15000 20000 25000 30000 35000 1.500 1.600 1.700 1.800 1.900 2.000 2.100 2.200 2.300 2.400 2.500 2.600 2.700 2.800 2.900 Horizontal Distance (ft): Project No. 041 1-1924 Filename: 1 1 1924_fig_GC867-C-1.cdr



### Figure GC 867-C-1. Inline 6855 and Crossline 34043 Showing Conditions Beneath Proposed W ellsite GC 867-C 15034.839 14132.748 13230.658 12328.568 1 1426.478 10524.387 9622.297 8720.207 7818.1 16 6916.026 6013.936 51 1 1.845 4209.755 3307.665 2405.574 1503.484 601.394 -300.697 -1202.787 -2104.877 -3006.968 -3909.058 -481 1.148 -5713.239 -6615.329 -7517.419 -8419.510 -9321.600 -10223.690 -1 1 125.781 -12027.871 -12929.961 -13832.052 -15034.839RELATIVEAMPLITUDETWO-WAYTIMETRAVEL(SEC)TWO-WAYTIMETRAVEL(SEC) GC 823 GC 867 Northwest Southeast

Inline 6855 SAL T

SAL T GC 823 GC 867 Southwest Northeast SEAFLOOR HORIZON 20 UNIT 1 UNIT 2

UNIT 3

SEAFLOOR HORIZON 20 HORIZON 35
HORIZON 40 T OP OF SAL T UNIT 1

UNIT 3 UNIT 4

Crossline 34043 Proposed W ellsite GC 867-C Proposed W ellsite GC 867-C

GC 866 GC 822

T OP OF SAL T

UNIT 2 HORIZON 35

GC 8246855.0 34000.0 Line: T race: 25000 30000 35000 1.400
1.500
1.600
1.700
1.800
1.900
2.000
2.100
2.200
2.300
2.400
2.500 Horizontal Distance (ft): Shallow W ater Flow and Gas Potential HIGH 0 1 2 3 0 = NEGLIGIBLE 1 = LOW 2 = MODERA

TE 3 = HIGH NEGLIGIBLE



### Figure GC 867-C-2. T

ophole Prognosis Chart, Proposed W ellsite C, Green Canyon Block 867 Filename: 1 1 1924_fig_GC867-C-2.cdr Project No. 041 1-1924 3-D Seismic Section Through Proposed W ellsite C X = 2,474,460 FT; Y

= 9,849,950 FT Crossline 34043 at Inline 6855 NW SE

Inline 6855 GC

823 PROPOSED WELLSITE CTWO-WAYTRAVELTIME (SEC) GC 867

SEAFLOOR W ater Flow Gas

HORIZON 20

T OP OF SAL TUnit 2 1.734

1.769

1.932 -4,250 -4,342

-4,782 92

532 92

255 Seafloor Slopes at 6.8° Southwest.

Lithology/Stratigraphy W A TER FLOW AND GAS POTENTIAL Horizon Horizon TWT (sec, bsl) Depth

(ft, bsl) Depth (ft, bml)Units Unit

(Interval) Thickness (ft)Unit 3 Potential Drilling Constraints

HORIZON 35 1.839 -4,527 277 185 V ery soft, pelagic drape at seafloor . Hemipelagic silty clays and thin mass-transport deposits. Alternating layers of hemipelagic silty clays with chaotic mass-transport deposits. Chaotic sequence created by salt movement. Mixture of silts and clays. Negligible potential for overpressured sands. Negligible potential for shallow gas. Low potential for overpressured sands. Low potential for shallow gas.

SAL T T op of salt Slopes at 18° to Southeast.Unit 1 Negligible potential for overpressured sands. Negligible potential for shallow gas.

TROUGH PEAK RELA TIVE AMPLITUDE10615 SHADOW WOOD DRIVE SUITE 200 HOUSTON, TEXAS 77043 Phone: (713) 468 - 1410

Fax: (713) 468 - 1438 E - mail: gems@gemsinc.com

- 1 - Proposed Well GC 867 - D May 20 , 2011 Project No. 0411 - 1924 Apache Deepwater, LLC 2000 W. Sam Houston Pkwy. South, Suite 1600 Houston , Texas 77042 - 3622 Attention: Mr. John A. Worthen 

### Site Clearance Letter Proposed Wellsite GC 8 67 - D

Block 8 67 (OCS - G - 33858 ) Green Canyon Area Gulf of Mexico Apache Deepwater, LLC ( Apache ) plans to drill an exploration well in Block 867 , of the Green Canyon Area ( GC ), Gulf of Mexico. This letter addresses specific seafloor and subsurface geologic conditions to a depth of approximately 1,021 ft below the mudline ( bml ) at the p roposed Wellsite GC 867 - D . The following discussion is based on findings provided within the main body of the geohazard report for Blocks 823 and 867 (GEMS Report No. 0411 - 1924). The surface location for proposed Wellsite GC 867 - D is in the southwestern quadrant of GC 823 . Apache provided the following coordinates: Proposed Wellsite GC 8 67 - D Spheroid & Datum: Clarke 1866, NAD27 Projection: UTM Zone 1 5 North Line Reference Block Calls ( SL i n GC 823 ) X : 2,47 3 , 15 0 ft Latitude: 27.13 84041402277 o N Inline 6 833 3,752 ft FSL Y: 9,85 6 , 232 ft Longitude: 90.4 39152132407 ° W Crossline 34 195 2 ,1 1 0 ft FWL Apache will drill this well using a moored vessel. An exact anchor pattern for the proposed well location is undetermined at this time. Maps GC 867 - D - 1 through GC 867 - D - 4 show an anchor radius representing a typical maximum length of chain and anchor on bottom is d isplayed at 10,000 ft from the proposed wellsite. A 1,000 ft buffer zoned beyond the limits of the anchor radius is also included, NTL 2009 - G40 (MMS, 2009 a ). 

### Attachments The maps and figures accompanying this letter have been extracted from the main rep ort’s original maps and 3 - D data volume and centered on the proposed well location. Map GC 867 - D - 1: Bathymetry Map Map GC 867 - D - 2: Seafloor Rendering Map GC 867 - D - 3: Seafloor Amplitude Rendering Map GC 867 - D - 4: Geologic Features Map Figure GC 867 - D - 1: Inline 6833 and Crossline 34195 Showing Condit ions Beneath Proposed Wellsite GC 867 - D Figure GC 867 - D - 2: Tophole Prognosis Chart, Proposed Wellsite GC 867 - D , G reen Canyon Block 867Project No. 0411 - 1924

- 2 - Proposed Well GC 867 - D 

### NTL Requirements The following report complies with the Bureau of Ocean Energy Management, Regulation, and Enforcement (BOEMRE; formerly the MMS) Notice to Lessees (NTLs) 2008 - G04, 2008 - G05 and 2009 - G40 (MMS, 200 8a, 2008b, and 200 9 a ). The proposed wellsite will be required to follow NTL 2008 - G06 with respect to pre - and post - spud ROV visual inspection surveys (MMS, 2008 c ). Pursuant to the recently released Pre - Seabed Disturbance Survey Mitigation issued by BOEMRE, the 2005 - G07 NTL (MMS, 2005) does not apply to GC 823/867 in terms of high - probability (MMS, 2008d) , bu t an archaeological assessment of the data must be performed prior to any bottom disturbing activities (BOEMRE, 2011b) . According to NTL 2008 - G05 (MMS, 2008b), 3 - D seismic reflection data may be used for shallow hazard assessments. A power spectrum anal ysis was conducted from the 3 - D seismic data cube provided by Apache 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 , over a time interval from the seafloor to ~0.371 second below mudline, i.e., the salt/sediment interface. We converted the amplitude vs. frequency spectrum, generated by the SMT software, to power vs. frequency by squaring the amplitude values as descri bed by J. A. Coffeen, 1978.

Power Spectrum Analysis Curve, Proposed Wellsite GC 867 - D 

### Man - Made Features There are existing wells in G C 823, GC 867, and in surrounding blocks. The closest well to Proposed Wellsite GC 867 - D, with a surface location in GC 823, is the BP Exploration Inc. , GC 823 - 001 well approximately 5,640 ft to the east - southeast (Maps GC 867 - D - 1 through GC 867 - D - 4). 0 0.2 0.4 0.6 0.8

1 1.2

0 10 20 30 40 50 60 70 80 90 100Power (amp2)

Frequency (hrz) POWER SPECTRUM

GC 867 - DProject No. 0411 - 1924

- 3 - Proposed Well GC 867 - D Other wells near the surface location of the Proposed Wellsite GC 867 - D are the BP Exploration Inc. , GC 866 - 001 and GC 823 - 002 wells. These wells are approximately 8,330 ft south - southwest and 12,900 ft east, respectively, of the proposed site and lie within the proposed mooring pattern. Proposed Wellsite GC 867 - D and its anchors lie within the “Military Warning Zone W - 92 ”. Military warning zones typically do not have any impact on exploration drilling operations or other oilfield activities. However, notifications to appropriate military commands need to be addressed by Apache (MMS, 2009b). Restrictions would only be enf orced during military operations in the area or during an emergency. 

### Water Depth and Seafloor Conditions T he water depth at the proposed location is - 3,944 ft (Map GC 867 - D - 1). The seafloor at the proposed location is slightly irregular and dips to the east - southeast at about 5.3  ̊. The proposed wellsite is located along the head of a southeasterly trending, arcuate valley (Map GC 867 - D - 2). The valley represents a Pleistocene slump scar. The valley occurs along the eastern margin of an extensive topogr aphic high. The topographic high is the seafloor expression of a shallow salt diapir. Water depths within the potential anchor mooring area range from about - 3,660 ft along a ridge line to the north - northeast to approximately - 4, 3 00 ft within the floor o f a valley to the south (Map GC 867 - D - 1). The seafloor within the potential anchoring area varies from smooth and featureless to very irregular. The seafloor irregularities include narrow ridges and gullies, faults, and mounds. Seafloor gradient within t he mooring pattern will average from 1° to 5°. The highest seafloor gradients in the area are associated with fault escarpments. Gradients of over 20  ̊ are associated with fault scarps that occur primarily north and south of the proposed location . The ove rburden in this area is relatively thin and has experienced uplift and erosion. Near - surface soils beneath a pelagic drape may be overconsolidated and stronger than typical slope soils. 

### Deepwater Benthic Communities The Seafloor Amplitude Rendering based on the 3 - D data volume (Map GC 867 - D - 3) shows normal or ambient amplitude along the seabed, with no indication of any hard - bottom or fluid expulsion events within 2,000 ft of the proposed GC 867 - D location. Based on the renderings and seismic profiles d eepwater benthic communities are not expected within 2,000 ft of the proposed GC 867 - D wellsite. Two mud mounds occur to the northwest of the location. The mound approximately 7,600 ft to the northwest is a known sit e of chemosynthetic communities. The second mound, approximately 4 , 700 ft to the northwest, does not have the high - amplitude seafloor returns but is likely caused by upwelling of gaseous muds. Both mounds need to be avoided. In addition p atches of high - amplitude seafloor returns occur approximately 8,600 ft to the south - southwest of the location. The patches are as sociated with seafloor faults (Maps GC 867 - D - 1 through GC 867 - D - 4). These features also have a high - potential for deepwater benthic communiti es. Therefore, anchors must avoid these features by at least 250 ft (MMS, 2009a). A number of seafloor faults occur within the proposed mooring pattern. The closest seafloor faults occur approximately 4 50 ft to the north. Except for the faults 8,600 ft to the south - southwest, no high - amplitude returns occur along the seabed escarpments; therefore, prolific hydrocarbon seepage or carbonate hardgrounds are unlikely. 

### Stratigraphy Inline 6833 and Crossline 34195 are the closest 3 - D lines to the proposed GC 867 - D location (Figure GC 867 - D - 1 ). The Tophole Prognosis Chart (Figure GC 867 - D - 2 ) shows the crossline annotated with calculated depths to the various horizons and predicted lithology of the sequences, along with their potential for shallow water flow an d shallow gas.Project No. 0411 - 1924

- 4 - Proposed Well GC 867 - D The 3 - D data volume was used to define the sedimentary section to a depth of approximately 1,021 ft (Figures GC 867 - D - 1 and GC 867 - D - 2). The section was divided into three units or sequences (Figure GC 867 - D - 1 ). The sequences represent v ariations in depositional environments and possible changes in soil strength and composition. The surficial unit, Unit 1 (Seafloor to Horizon 20 ), to approximately 124 ft bml, consists of a very soft pelagic drape underlain with hemipelagic silty clays and thin, mass - transport deposits . Very soft clays with high water content will likely exist at the seabed. However, the underlying section has been uplifted and eroded. F irm, overconsolidated soils may be encountered beneath the thin (~10 ft) pelagic drap e . Unit 2 (Horizon 20 to Horizon 35) consists of bedded hemipelagic clays interbedde d with thin chaotic mass - transport deposits. The sediments will be mud - rich; however, some thin sand seams and pockets are possible. The combined thickness of Units 1 and 2 is approximately 478 ft (Figure GC 867 - D - 2 ). Unit 3 is a sequence bounded by Horizon 35 and the top of salt ( Figures GC 867 - D - 1 and GC 867 - D - 2). The upper portion of the sequence (478 ft to 876 ft bml) is primarily composed of mud - rich turbidites. The lower portion of Unit 3 (876 ft to 1,021 ft bml) is a chaotic interval affected by shallow salt emplacement and will likely consist of a mixt ure of silts and clays. Unit 3 is approximately 543 ft thick. The top of salt is predicted to be 1,021 ft bml (~4,965 ft bsl). The salt surface dips to the northeast at approximately 43°. 

### Faults Two faults will be intersected by the well bore beneath proposed Wellsite GC 867 - D (Figure s GC 867 - D - 1 and GC 867 - D - 2 ). The borehole will intersect the shallowest fault near the base of Unit 2, at approximately 336 ft bml. A deeper fault will be intersected in the upper portion of the Horizon 35 to Top of Sal t sequence (Unit 3), at a depth of about 737 ft bml. These faults may be possible loss circulation zones. 

### Shallow Water Flow Unit 2 between Horizons 20 and 35 is possibly the regional “Red Unit” slope - fan sequence. However, the top of the unit is only 1 24 ft bml at proposed Wellsite D (Figure GC 867 - D - 2). The entire unit is 354 ft thick. At this location, Unit 2 is an unlikely zone for overpressured sand layers. The existing GC 823 - 001 well is approximately 5, 640 ft to the east - southea s t of the propo sed GC 867 - D wellsite. A “low” severity shallow water flow occurred in the GC 823 - 001 well at 1,715 ft bml ( - 5,840 ft bsl ). Based on the reported depth the flow occurred in the lower portion of Unit 4 within a generally low amplitude interval of discontinuous to chaotic reflections. Unit 4 is not present beneath the GC 867 - D wellsite. However, an interval within Unit 3 (6 69 ft to 876 ft) shows bedded reflectors with moderate amplitudes. This interval consist s of turbidites and may have thin sand layers. The potential for overpressured sands within this interval is moderate. The potential for the rest of the section is lo w to negligible. 

### Shallow Gas The well path will not penetrate any high - amplitude events between the seafloor and the top of salt (Figure GC 867 - D - 2). There is a negligible to low potential for shallow gas in this section. 

### Closing The seafloor and near - surface conditions at Proposed Wellsite GC 867 - D , Green Canyon Block 867 (OCS G - 33 858), appear suitable for exploration drilling operations. The existing wellsites and the potential benthic communities will need to be avoided by anch ors supporting a drilling vessel at the proposed location. Engineers should be aware that the soils above salt may be stronger and more consolidated than typical slope sediments.Project No. 0411 - 1924

- 5 - Proposed Well GC 867 - D Sincerely, GEOSCIENCE EARTH & MARINE SERVICES, INC. ®

Thomas W. Neurauter Ph. D. Daniel Lanier Senior Marine Geologist Vice - President/Marine Geologist Attachments ( 4 Maps, 2 Figures) Distribution: Mr . John Worthen , Apache, Houston, TX. ( 6 ) References: Bureau of Ocean Energy Management and Enforcement, 2011a , ASCII Data Files, published on the BOEMRE Gulf of Mexico Region Homepage, <http://www.gomr.mms.gov/homepg/pubinfo/freeasci/freedesc.html>, accessed May , 20 11 . Bureau of Ocean Energy Management, Regulation, and Enforcement , 20 11b, Pre - Seabed Disturbance S urvey Mitigation < http://www.gomr.boemre.gov/homepg/regulate/environ/archaeological/Conditional - Archaeological Mitigation.pdf >. Coffeen, J. A., 1978, Seismic exploration fundamentals: Tulsa, the Petroleum Publishing Co., p. 125. Minerals Management Service , 2005, 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, Archaeological resource surveys and reports: U. S. Department of the Interior, Min erals Management Service, Gulf of Mexico, NTL 2005 - G07. Minerals Management Service, 2008a, 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 expl oration plans and development operations coordination documents: U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008 - G04. Effective Date May 1, 2008. Minerals Management Service, 2008 b , 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 Servi ce, Gulf of Mexico, NTL 2008 - G05. Minerals Management Service, 2008 c , 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. D epartment of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2008 - G06. Minerals Management Service, 2008 d , Notice to lessees and operators (NTL) of federal oil and gas leases and pipeline right - of - way (ROW) holders on the outer continental s helf (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, 20 09a , 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 200 9 - G 4 0.Project No. 0411 - 1924

- 6 - Proposed Well GC 867 - D Minerals Management Service, 2009b, Notice to lessees and operators of federal oil and gas leases and pipeline right of

- way holders on the outer continental shelf, Gulf of Mexico OCS region, Military Warning and Water Test Areas: U. S. Department of the Interior, Minerals Management Service, Gulf of Mexico, NTL 2009 - G06. Effective Date April 22, 2009.