UNITED STATES GOVERNMENT MEMORANDUM

To: Public Information (MS 5030)

Plans Section, Office of Field 

Operations (MS 5231)

Public Information copy of Exploration Plan

Control # - N-09702

Type - Initial Exploration Plan

Lease(s) - OCS-G34444 Block - 554 Mississippi Canyon Area

OCS-G34445 Block - 555 Mississippi Canyon Area

Operator - Apache Deepwater LLC

Subsea Well A (MC 554) and Subsea Wells A and B (MC 555)

Not Found

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

should be addressed in an Environmental Assessment.

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

Karen Dunlap

Plan Coordinator

Description -

Rig Type -

Subject:

From:

May 10, 2013
PUBLIC COPY 

RECORD OF CHANGES

Operator: Apache Deepwater LLC 

Lease: OCS-G 34444/34445 

Area/Block: Mississippi Canyon Blocks 554/555 

Plan Type: Joint Initial Exploration Plan 

Plan Control No.: N-9702 

Plan Submitted: April 25, 2013 

BOEM Coordinator: Karen Dunlap 

Date Appendix Page Revision

3/6/2013 H Submit .nod and .mer files, previous not able to open 

3/13/2013 H Submit .nod file again, BOEM having trouble opening 

previous one again 

3/28/2013 A All Storage Tanks table - revised total capacity for dirty lube 

oil

3/28/2013 BOEM-0137 Answer YES to question regarding "disturbing a highprob arch area, revise anchor radius to 11,500 to be 

consistent with Site Clearance Letters 

3/28/2013 B B-1 Revise the drilling fluids chart 

3/28/2013 C C-4 Revise all Site Clearance Location Letters with the 

correct anchor radius to be consistent with the BOEM0137 form 

3/28/2013 E Revise the verbiage to state an arch report was submitted 

and to be consistent with the EIA 

3/28/2013 F F-1 Revise Waste & Discharge tables to explain completion 

of the wells 

3/28/2013 G Attach the calculation spreadsheets 

3/28/2013 H H-1 OSRP currently under USCG review, will resubmit after 

given approval 

3/28/2013 L L-1 Revise Support Vessels table, remove unnecessary 

information not required 

4/18/13 H H-1 OSRP Approval 4/18/13 

 
JOINT INITIAL EXPLORATION PLAN 

PUBLIC COPY 

April 25, 2013 

Area/Block: Mississippi Canyon Blocks 554/555 

Lease Number(s): OCS-G 34444/34445 

Prospect Name: Guadalupe 

Offshore: Louisiana 

Prepared By: 

Ms. Terri Young 

Apache Deepwater LLC 

2000 W. Sam Houston Pkwy. S., Suite 1600 

Houston, Texas 77042 

(713) 296-7456 

Terri.young@apachecorp.com

Plan No.: 9702 

Assigned to: Karen Dunlap 

Date of Submittal: April 25, 2013 

Estimated Start-up Date: September 15, 2013 
JOINT INITIAL EXPLORATION PLAN DOCUMENT 

LEASE OCS-G 34444/34445 

MISSISSIPPI CANYON BLOCKS 554/555 

TABLE OF CONTENTS 

SECTION A Plan Contents

SECTION B General Information

SECTION C Geological, Geophysical Information

SECTION D H2S Information

SECTION E Biological, Physical and Socioeconomic Information

SECTION F Wastes and Discharge Information

SECTION G Air Emissions Information

SECTION H Oil Spills Information

SECTION I Environmental Monitoring Information

SECTION J Lease Stipulations Information

SECTION K Environmental Mitigation Measures Information

SECTION L Support Vessels and Aircraft Information

SECTION M Onshore Support Facilities Information

SECTION N Coastal Zone Management Act (CZMA) Information

SECTION O Environmental Impact Analysis

SECTION P Administrative Information
LIST OF ATTACHMENTS 

A-1 OCS Plan Information Form 

A-2 Well Location Plat 

A-3 Bathymetry Map 

A-4 Pay.Gov Receipt 

C-4 Shallow Hazard Assessment 

F-1 Projected Generated Wastes 

H-1 Spill Response Discussion for NEPA Analysis 

L-1 Solid and Liquid Waste Transportation 

L-2 Vicinity Map 

N-1 Coastal Zone Management Consistency Certification 

O-1 Environmental Impact Analysis 
Apache Deepwater LLC	 	 Page A‐1

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

SECTION A 

PLAN CONTENTS 

(30 CFR 550.211 and 550.241) 

A. PLAN INFORMATION FORM

Apache Deepwater LLC submits this Joint Initial Exploration Plan to propose the drill and 

completion of three (3) well locations in Mississippi Canyon Blocks 554/555. Tentative 

schedules from start to finish of the drilling and completion activities and information regarding 

the proposed locations are included on the OCS Plan Information Form BOEM-0137, included 

as Attachment A-1.

B. LOCATION 

A Well Location Map depicting the proposed surface locations for the proposed wells is included 

as Attachment A-2. A Bathymetry Map showing the water depths across the lease block is 

included as Attachment A-3. These attachments are in accordance with the Notice to Lessees 

(NTL) 2008-G04. 

C. SAFETY AND POLLUTION PREVENTION FEATURES 

A description of the drilling unit is included on the OCS Plan Information Form. Rig 

specifications will be made part of each Application for Permit to Drill (APD). 

Safety features on the drilling unit will include well control, pollution prevention and blowout 

prevention equipment as described in Title 30 CFR Part 550, Subparts C, D, E and F; and as 

further clarified by BOEM Notices to Lessees and current policy making invoked by the BOEM 

Environmental Protection Agency and the U.S. Coast Guard. 

Appropriate life rafts, life jackets, ring buoys, etc., will be maintained on the facility at all times 

as mandated by the U.S. Coast Guard regulations contained in Title 33 CFR. 

Pollution prevention measures include installation, of curbs, gutters, drip pans and drains on 

drilling deck areas to collect all contaminants and debris. 
Apache Deepwater LLC	 	 Page A‐2

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

D. STORAGE TANKS AND/OR PRODUCTION VESSELS 

The Mississippi Canyon Blocks 554/555 wells will be drilled with a Semisubmersible or DP 

Semisubmersible unit. All facility tanks of 25 barrels or more. 

Type of 

Storage Tank 

Type of 

Facility (Rig) 

Tank 

Capacity 

(bbls) 

Number 

of 

Tanks 

Total 

Capacity 

(bbls) 

Fluid 

Gravity 

(APIDegree) 

Fuel Oil (Marine Diesel) Semisubmersible 104.7 1 104.7 35o

Fuel Oil Day Semisubmersible 97.6 1 97.6 35o

Emergency Generator Semisubmersible 5.5 1 5.5 35o

Forward Hull – Fuel Oil Semisubmersible 3416 1 3416 35o

Lower AFT Hull – Fuel Oil Semisubmersible 3416 1 3416 35o

Lube Oil Services Semisubmersible 61.3 7 429.1 26o

Dirty Lube Oil Semisubmersible 30.1 1 30.1 26o

Dirty Bilge Semisubmersible N/A N/A N/A N/A 

Fuel Oil (Marine Diesel) DP Semisubmersible 164 1 164 35o

Fuel Oil Day DP Semisubmersible 262 1 262 35o

Emergency Generator DP Semisubmersible 30.76 1 30.76 35o

Forward Hull – Fuel Oil DP Semisubmersible 4540.9 2 9081.84 35o

Lower AFT Hull – Fuel Oil DP Semisubmersible 6790 2 13580 35o

Lube Oil Services DP Semisubmersible 115 1 115 26o

Dirty Lube Oil DP Semisubmersible 33 2 66 26o

Dirty Bilge DP Semisubmersible N/A N/A N/A N/A 

E. ADDITIONAL MEASURES 

Apache Deepwater does not propose additional safety, pollution prevention or early spill 

detection measures beyond those required by 30 CFR 550. 

F. COST RECOVERY FEE 

A Pay.Gov receipt in the amount of $11,019.00 for the cost recover fees associated with this plan 

is included as Attachment A-4.
U.S. Department of the Interior OMB Control Number: 1010-0151 

Bureau of Ocean Energy Management OMB Approval Expires: 12/31/2014

OCS PLAN INFORMATION FORM

General Information

Type of OCS Plan: Exploration Plan (EP) Development Operations Coordination Document (DOCD) 

Company Name: BOEM Operator Number: 

Address: Contact Person: 

Phone Number: 

E-Mail Address: 

Lease(s): Area: Block(s): Project Name (If Applicable): 

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

Description of Proposed Activities (Mark all that apply)

Exploration drilling Development drilling 

Well completion Installation of production platform 

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

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

Installation of subsea wellheads and/or manifolds Commence production 

Installation of lease term pipelines Other (Specify and describe) 

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

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

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

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

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

Tentative Schedule of Proposed Activities

Proposed Activity Start Date End Date No. of Days

 

Description of Drilling Rig Description of Production Platform

Jackup Drillship Caisson Tension leg platform 

Gorilla Jackup Platform rig Well protector Compliant tower 

Semisubmersible Submersible Fixed platform Guyed tower 

DP Semisubmersible Other (Attach Description) Subsea manifold Floating production system 

Drilling Rig Name (If Known): Spar Other (Attach Description) 

Description of Lease Term Pipelines

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

 

FORM BOEM-0137 (December 2011 - Supersedes all previous editions of form BOEM-0137 which may not be used.) 

Page 1 of 2 

ATTACHMENT A-1

Apache Deepwater LLC 03165

2000 W. Sam Houston Pkwy, South Terri Young

Suite 1600 713-296-7456

Houston, TX 77042 terri.young@apachecorp.com

OCS-G 34444/34445 MC 554/555 Guadalupe

X Martin Fuel Docks, Fourchon, LA 50

X

X

X

X

X

X

X

X

Drill, complete and test three (3) locations and install subsea wellheads

MC 555 Location A 9/15/2013 12/18/2013 94

MC 554 Location A 1/1/2014 4/5/2014 94

MC 555 Location B 1/1/2015 4/5/2015 94

X

X
OCS PLAN INFORMATION FORM (CONTINUED)

Include one copy of this page for each proposed well/structure

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or 

structure, reference previous name): 

Previously reviewed under an approved EP or 

DOCD? 

Yes No 

Is this an existing well 

or structure? 

Yes No If this is an existing well or structure, list the 

Complex ID or API No. 

Do you plan to use a subsea BOP or a surface BOP on a floating facility to conduct your proposed activities? Yes No 

WCD info For wells, volume of uncontrolled 

blowout (Bbls/day): 

For structures, volume of all storage and 

pipelines (Bbls):

API Gravity of 

fluid

Surface Location Bottom-Hole Location (For Wells) Completion (For multiple completions, 

enter separate lines) 

Lease No. OCS OCS OCS

OCS

Area Name 

Block No. 

Blockline

Departures 

(in feet)

N/S Departure: F____ L N/S Departure: F____ L N/S Departure: F____ L

N/S Departure: F____ L 

N/S Departure: F____ L 

E/W Departure: F____ L E/W Departure: F____ L E/W Departure: F____ L 

E/W Departure: F____ L 

E/W Departure: F____ L 

Lambert XY

coordinates

X: X: X: 

X:

X:

Y: Y: Y:

Y:

Y:

Latitude/

Longitude

Latitude Latitude Latitude 

Latitude

Latitude

Longitude Longitude Longitude 

Longitude

Longitude

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

Anchor Radius (if applicable) in feet: 

MD (Feet): 

MD (Feet): 

MD (Feet): 

TVD (Feet): 

TVD (Feet): 

TVD (Feet): 

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

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor Chain on Seafloor 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

Form BOEM- 0137 (December 2011- Supersedes all previous editions of this form which may not be used.) Page 2 of 4

A X

X

X

32

G-34444

Mississippi Canyon

554

S

7,721' E

631'

1,108,169'

10,319,561'

28.4266452

-88.6563833

4,647'

11,500'

444,250
OCS PLAN INFORMATION FORM (CONTINUED)

Include one copy of this page for each proposed well/structure

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or 

structure, reference previous name): 

Previously reviewed under an approved EP or 

DOCD? 

Yes No 

Is this an existing well 

or structure? 

Yes No If this is an existing well or structure, list the 

Complex ID or API No. 

Do you plan to use a subsea BOP or a surface BOP on a floating facility to conduct your proposed activities? Yes No 

WCD info For wells, volume of uncontrolled 

blowout (Bbls/day): 

For structures, volume of all storage and 

pipelines (Bbls):

API Gravity of 

fluid

Surface Location Bottom-Hole Location (For Wells) Completion (For multiple completions, 

enter separate lines) 

Lease No. OCS OCS OCS

OCS

Area Name 

Block No. 

Blockline

Departures 

(in feet)

N/S Departure: F____ L N/S Departure: F____ L N/S Departure: F____ L

N/S Departure: F____ L 

N/S Departure: F____ L 

E/W Departure: F____ L E/W Departure: F____ L E/W Departure: F____ L 

E/W Departure: F____ L 

E/W Departure: F____ L 

Lambert XY

coordinates

X: X: X: 

X:

X:

Y: Y: Y:

Y:

Y:

Latitude/

Longitude

Latitude Latitude Latitude 

Latitude

Latitude

Longitude Longitude Longitude 

Longitude

Longitude

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

Anchor Radius (if applicable) in feet: 

MD (Feet): 

MD (Feet): 

MD (Feet): 

TVD (Feet): 

TVD (Feet): 

TVD (Feet): 

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

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor Chain on Seafloor 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

Form BOEM- 0137 (December 2011- Supersedes all previous editions of this form which may not be used.) Page 2 of 4

A X

X

X

G-34445

Mississippi Canyon

555

S

8,195' W

357'

1,109,157'

10,320,035'

28.4279862

-88.6533299

4,651'

11,500'
OCS PLAN INFORMATION FORM (CONTINUED)

Include one copy of this page for each proposed well/structure

Proposed Well/Structure Location

Well or Structure Name/Number (If renaming well or 

structure, reference previous name): 

Previously reviewed under an approved EP or 

DOCD? 

Yes No 

Is this an existing well 

or structure? 

Yes No If this is an existing well or structure, list the 

Complex ID or API No. 

Do you plan to use a subsea BOP or a surface BOP on a floating facility to conduct your proposed activities? Yes No 

WCD info For wells, volume of uncontrolled 

blowout (Bbls/day): 

For structures, volume of all storage and 

pipelines (Bbls):

API Gravity of 

fluid

Surface Location Bottom-Hole Location (For Wells) Completion (For multiple completions, 

enter separate lines) 

Lease No. OCS OCS OCS

OCS

Area Name 

Block No. 

Blockline

Departures 

(in feet)

N/S Departure: F____ L N/S Departure: F____ L N/S Departure: F____ L

N/S Departure: F____ L 

N/S Departure: F____ L 

E/W Departure: F____ L E/W Departure: F____ L E/W Departure: F____ L 

E/W Departure: F____ L 

E/W Departure: F____ L 

Lambert XY

coordinates

X: X: X: 

X:

X:

Y: Y: Y:

Y:

Y:

Latitude/

Longitude

Latitude Latitude Latitude 

Latitude

Latitude

Longitude Longitude Longitude 

Longitude

Longitude

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

Anchor Radius (if applicable) in feet: 

MD (Feet): 

MD (Feet): 

MD (Feet): 

TVD (Feet): 

TVD (Feet): 

TVD (Feet): 

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

Anchor Name 

 or No. 

Area Block X Coordinate Y Coordinate Length of Anchor Chain on Seafloor 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

X = Y = 

Form BOEM- 0137 (December 2011- Supersedes all previous editions of this form which may not be used.) Page 2 of 4

B X

X

X

G-34445

Mississippi Canyon

555

S

4,461' W

7,791'

1,116,591'

10,316,301'

28.4179954

-88.6300449

4,760'

11,500'
Exxon-Mobil

1

554

598

510

555

599

511

Y = 10,327,680'

Y = 10,311,840'

X = 1,092,960'

X = 1,108,800'

X = 1,124,640'

SURFACE

LOCATION MAP

1/28/13 1" = 4000'

APACHE DEEPWATER, LLC

Mississippi Canyon 554/555

OCS-G 34444/34445 

APA

MC 554

Loc.A

APA

MC 555

Loc.A

APA

MC 555

Loc.B

SL

SL

SL

Apache Loc. MC 554 A

Surface Location

Apache Loc. MC 555 A

Surface Location

Apache Loc. MC 555 B

Surface Location

7,721’ FSL & 631’ FEL of MC 554

X = 1,108,169'

Y = 10,319,561'

Lat. = 28.4266452

 28 25' 35.932"

Long. = -88.6563833

 -88 39' 22.980"

8,195’ FSL & 357’ FWL of MC 555

X = 1,109,157'

Y = 10,320,035'

Lat. = 28.4279862

 28 25' 40.750"

Long. = -88.6533299

 -88 39' 11.988"

4,461’ FSL & 7,791’ FWL of MC 555

X = 1,116,591'

Y = 10,316,301'

Lat. = 28.4179954

 28 25' 04.783"

Long. = -88.6300449

 -88 37' 48.162"

7,721' FSL

8,195' FSL

4,461' FSL

357' FWL

631' FEL

7,791' FWL
Exxon-Mobil

1

554

598

510

555

599

511

Y = 10,327,680'

Y = 10,311,840'

X = 1,092,960'

X = 1,108,800'

X = 1,124,640'

BATHYMETRY

MAP

1/28/13 1" = 4000' C.I. = 20'

APACHE DEEPWATER, LLC

Mississippi Canyon 554/555

OCS-G 34444/34445 

-4,500'

-4,600'

-4,700'

-4,800'

-4,900'

-4,900'

APA

MC 554

Loc.A

APA

MC 555

Loc.A

APA

MC 555

Loc.B

SL

SL

SL
Online Payment

Step 3: Confirm Payment 1 | 2 | 3

Thank you. 

Your transaction has been successfully completed. 

Pay.gov Tracking Information

Application Name: BOEM Exploration Plan - BF

Pay.gov Tracking ID: 259Q4AQ0

Agency Tracking ID: 74417580865

Transaction Date and Time: 03/01/2013 12:22 EST

Payment Summary

Address Information

Account 

Holder Name: Mariner Energy, Inc. 

Billing 

Address:

2000 W. Sam 

Houston Pkwy. S, 

Suite 2000 

Billing 

Address 2:

City: Houston 

State / 

Province: TX 

Zip / Postal 

Code: 77042 

Country: USA 

Account Information

Card Type: American Express 

Card 

Number: ************4008 

Region: Gulf of Mexico 

Contact: 

Terri Young 713-296-

7456 

Company 

Name/No: 

Apache Deepwater 

LLC, 03165 

Lease 

Number(s): 34444, 34445, , , 

Area-Block: 

Mississippi Canyon 

MC, 554: Mississippi 

Canyon MC, 555: , : , : 

, 

Surface 

Locations: 3 

Payment Information

Payment Amount: $11,019.00

Transaction Date 

and Time:

03/01/2013 

12:22 EST

Pay.gov - Online Payment Page 1 of 1

https://www.pay.gov/paygov/payments/authorizePlasticCardPayment.html 3/1/2013
Apache Deepwater LLC	 	 Page B‐1

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

SECTION B 

GENERAL INFORMATION 

(30 CFR 550.213 and 550.243) 

A. APPLICATIONS AND PERMITS

The table below lists the additional permits/applications to be filed before operations can 

commence under this EP: 

Application/Permit Issuing Agency Status 

Application for Permit to Drill (APD) BSEE To be submitted 

 

B. DRILLING FLUIDS 

Type of Drilling Fluid Estimated Volume of Drilling Fluid to be 

Used per Well 

Water-based (seawater, freshwater, barite) 40,000 bbl / well total 

Oil-based (diesel, minerals, oil) 0 bbl / well total 

Synthetic-based (internal olefin, ester) 14,255 bbls / well total 

Product Name Amount to be Used 

M-I Bar 3,152,000 lbs / well total 

Synthetic B 568,225 gal / well total 

Suremul 14,560 gal / well total 

Surewet 4,625 gal / well total 

Rheflat 1,660 gal / well total 

Rhethik 1,245 gal / well total 

Lime 46,250 lbs / well total 

Calcium Chloride 134,300 lbs / well total 

C. NEW OR UNUSUAL TECHNOLOGY 

Apache Deepwater does not propose to use any new or unusual technology to carry out the 

proposed exploration activities. 

D. BONDING STATEMENT 

The bond requirements for the activities and facilities proposed in this EP are satisfied by a 

$3,000,000.00 areawide development bond, furnished and maintained according to 30 CFR 256 

subpart I; NTL No. 2000-G16 - “Guidelines for General Lease Surety Bonds”; and additional 

security under 30 CFR 256.53(d) and National NTL No. 2008-N07 - “Supplemental Bond 

Procedures”. 
Apache Deepwater LLC	 	 Page B‐2

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

E. OIL SPILL FINANCE RESPONSIBILITY (OSFR) 

Apache Deepwater LLC, (company number 03165) has demonstrated oil spill financial 

responsibility for the facilities proposed in this EP according to 30 CFR Part 253 and NTL No. 

2008-N05 - “Guidelines for Oil Spill Financial Responsibility for Covered Facilities”. 

F. DEEPWATER WELL CONTROL STATEMENT 

Apache Deepwater LLC, (company number 03165) has the financial capability to drill a relief 

well and conduct other emergency well control operations. 

G. BLOWOUT SCENARIO 

Estimated maximum flow rate

The estimated maximum flow rate would occur in the objective section, if a kick were taken and 

the well blew out. The maximum Worst Case Discharge (WCD) modeled for this scenario is 

444,250 BOPD. 

Maximum duration of blowout (days) 

The duration of the blowout will be a function of the well bridging over, the ability of surface 

intervention to shut or contain the well or, as a last resort, drilling a relief well to kill the 

blowout. The expected maximum time frames for uncontrolled flow in each of the different 

operational outcomes would be as follows: 

 Bridging Over in 2 Days, 

 Surface Intervention in 15 Days, 

 A Relief Well in 101 Days. 

Maximum discharge volume 

The following table is a linear estimate of the maximum discharge volume for each of the 

aforementioned operational outcomes. 

Operational 

Outcome 

Maximum 

Discharge Rate 

(bbl/day) 

Discharge 

Duration 

(days) 

Maximum 

Discharge 

Volume (bbl) 

Bridging Over 444,250 2 888,500 

Surface 

Intervention 

444,250 15 6,663,750 

Relief Well 444,250 101 44,869,250

Potential of wellbore to bridge over during a blowout 

There is significant potential for the wellbore to bridge over during the WCD blowout. Bridging 

is likely to occur due to the extreme drawdown calculated between the formation and the open 

hole section. A Merlin reservoir simulation model was used to investigate the well conditions 

during the WCD blowout scenario. The estimated reservoir pressure is 18,460 psi. The reservoir 
Apache Deepwater LLC	 	 Page B‐3

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

model estimates bottom hole flowing pressures, based upon reservoir properties and flow rates. 

The calculated drawdown is modeled to be 8,403 psi. 

In our experience in the deepwater GOM, we strive to limit the estimated total drawdown on a 

producing interval to reduce the risk of wellbore collapse and sand/fines migration into a well. 

We limit the drawdown to less than 1,000 psi by reducing the rates the wells produce and by 

completing each well with a cased hole, frac-pack completion. 

There is a strong likelihood of wellbore bridging over: 

 Drawdown is estimated to be 8.4 times or greater than our operating practices, 

 The blowout occurs in a long open hole section of the well, with no benefit of 

casing or a frac-pack completion, 

 If any water zones are exposed this will accelerate wellbore collapse and bridging, 

 Wellbore collapse and bridge-over, under the conditions cited are estimated not to 

exceed 2 days. 

Surface intervention to stop the blowout 

In the event of a blowout and assuming the blowout prevention equipment is still intact; the 

subsea BOP will be used for successful shut-in of the well. The well would then be killed and 

re-entered to either abandon or return to normal operations. Surface intervention would be the 

first line of defense after a blowout occurs. The specific intervention technique chosen will 

depend on actual conditions and ability to access the existing well. 

In the event that the subsea BOP is inoperable, the surface intervention would employ the Marine 

Well Containment Company (MWCC) containment system to achieve successful containment of 

the well. The system will be employed, while simultaneously initiating relief well planning and 

operations. Specifics will be submitted within the Well Containment Plan. 

Typically blowouts can be controlled with surface intervention, with a good likelihood of success 

and in a relatively short time frame, as long as, the subsea casing, wellhead and BOP’s are not 

damaged beyond use. The intervention technique chosen will depend on actual conditions and 

ability to access the existing well. There can be simple solutions such as rig up and bullhead kill 

mud or more complex solutions, but the solution will depend on wellbore conditions. 

Surface intervention time estimate 

The assumption is that the well has an uncontrolled blowout and the MODU has sunk with 

displacement from the wellhead. Additionally, it assumes that debris removal will be required to 

gain access to the subsea BOP system. The ROV has been deployed and was unsuccessful in 

shutting in the well, using the existing subsea BOP control panel. The scenario employs the 

aforementioned containment system’s capping BOP. 

The table on the next page describes the estimated time required to shut in and secure the well 

using the containment system or capping stack. Note that these operations all basically start at 

the same point in time and are performed in parallel. The entire operation is estimated to take 15 

days from start of site assessment until the capping stack has been deployed and the well shut in. 
Apache Deepwater LLC	 	 Page B‐4

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

Duration of a well capping operation 

Operation Incremental 

Duration 

(days) 

Cumulative Time Since 

Event Start 

(days) 

Assess wellbore conditions for surface 

intervention requirements. Conduct 

notifications to the regulatory agencies 

and primary contractors. 

2 2 

Site Preparation which includes 

mobilizing and deployment of the 

IWOCS system and Dispersant 

system. 

5 5 

Debris removal including mobilization 

of ROV boat and construction support 

vessel and execution of debris removal 

plan. 

7 7 

Well capping and/or cap and flow 

operations which include mobilization, 

deployment, and installation of the 

well containment system. 

15 15 

Relief Well 

It is preferred to drill relief wells from an open water location, rather than a platform location. 

Open water locations provide the best option on designing a simpler intercept well and allow a 

greater choice on rig availability. There are not any platforms in the vicinity; therefore it is not 

feasible to consider a platform as a relief well location. 

Relief well location and drilling strategy 

Proprietary Information 
Apache Deepwater LLC	 	 Page B‐5

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

Relief well rig availability 

The rigs listed below could be available for relief well operations: 

Rig Name Contractor 

Rated 

Water 

Depth 

MODU Type Rig Status 

Ensco 8500 Ensco 8,500’ DP Semisubmersible Contracted GOM

Ensco 8501 Ensco 8,500’ DP Semisubmersible Contracted GOM

Ensco 8502 Ensco 8,500’ DP Semisubmersible Contracted GOM

Ensco 8506 Ensco 8,500’ DP Semisubmersible Contracted GOM

West Sirius Seadrill 10,000’ DP Semisubmersible Contracted GOM

Maersk Developer Maersk 10,000’ DP Semisubmersible Contracted GOM

Danny Adkins Noble 12,000’ DP Semisubmersible Contracted GOM

C.R. Luigs Transocean 10,000’ DP Drill Ship Contracted GOM

Discoverer Deep Seas Transocean 10,000’ DP Drill Ship Contracted GOM

Relief well package constraints 

The proposed rigs for relief well operations have suitable drilling packages with sufficient 

capabilities to work in the subject water depths and drill to the required relief well depth. The 

BOP systems have met the BSEE certification requirements and will be re-inspected in transit, 

prior to drilling a relief well to the required true vertical depth. 

Relief well rig contract and mobilization timing 

A suitable rig could be selected and a contract finalized in 48 hours after undertaking the 

decision to begin relief well operations. Backup tubular goods and wellhead systems are 

maintained in stock for each well. Mobilization of equipment and services to the rig for the 

relief well could be completed while operations required to suspend the rig’s current activity 

were taking place. The time required to contract, mobilize, drill a relief well and kill the blowout 

well is estimated at 101 days and is summarized below. The relief well, MC 555 Location A, was 

used for this example. 
Apache Deepwater LLC	 	 Page B‐6

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

Duration of relief well 

Description Days Cumulative Days 

Well Control Assessment. Identify suitable 

MODU for relief well operations 2 2 

MODU suspends operations from current well. 

Contract to be executed and Well Spud 

Equipment is mobilized 

14 16 

Mobilize Rig and install 36” Structural Casing 10 26 

Spud and drill to the top of the zone of interest 

and set casing. 65 91 

Mag-Range relief well into intersecting position. 5 96 

R/U pumping equipment and kill well. 5 101 

R/D Pumping Equipment, PA Wellbore, Pull 

Riser, and Demobilize 15 116 

Blowout Prevention and Intervention 

Summary of prevention measures 

Apache Deepwater LLC has maintained a safe track record of prudent operations in the GOM 

deepwater environment. It will continue to implement its safe operating practices to enhance its 

operating risk reduction program. In addition to the safe operating practices, the following 

measures will be implemented into well design, drilling and completion operations. 

 BOP Certification, BOP Drills, Pit Drill’s and all other required BSEE testing 

requirements, 

 Current Well Control Certification for all Drilling and Completion Rig Site Supervisors, 

 Taking Slow Pump Rate measurements during all open hole operations and critical cased 

hole operations, 

 Updating Kill Sheets during each tour and posting the same on the rig floor, 

 Maintain a current BOP to RKB spaceout chart, 

 Monitoring wellbore fill-ups and displacements during trips, by the Well Site Supervisor, 

 Maintain the necessary circulating swages, TIW Valves and IBOP on the rig floor at all 

times during operations and function test these valves during each tour. 

The utilization of Pre-Job Safety meetings will continue to be implemented prior to each 

operation with all of the rig crews. These are intended to create a behavior based safety program 

and promote an atmosphere within the Apache and rig crew interface, such that a “Stop the Job” 

mentality is promoted across the rig contractor’s crew, empowering every crew member to 

question the safety of each operation. 
Apache Deepwater LLC	 	 Page B‐7

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

Early well control intervention 

In the event of a blowout situation, due to failed BOP equipment and uncontrolled flow at the 

seafloor or at surface, assuming all other surface controlled actuation measures have failed or are 

inaccessible, a ROV will fly into position at the BOP subsea actuation panel and actuate the 

shear ram or pipe rams to establish containment. 

If the riser system and rig have been compromised, then debris removal will be initiated to obtain 

clear access to the BOP. A Capping Stack will be employed to achieve successful containment of 

the well. Once containment is established and wellbore pressure testing and assessment is 

completed by Apache and Well Control Specialist, well kill operations can be initiated through 

the existing wellbore. 

Well control engineering services 

Apache will have service agreements in place with Wild Well Control and Boots and Coots 

International Well Control prior to commencement of well operations. In the event of a blowout 

situation, these companies will be contacted to assist in the detailed design and implementation 

of well control and/or relief well operations. 

Additional prevention & mitigation techniques 

Pursuant to wellbore cementing and zonal isolation techniques, all cementing operations will be 

modeled and designed under the guidelines set forth in API Recommended Practice 65 Part 1 & 

2. Operations will be dictated by the rules and requirements set forth in Federal Regulations, 

under the wellbore cementing requirements. 

API Standard 53 for Blowout Prevention Equipment Systems for Drilling Wells and 

Recommended Practice 16Q for Marine Drilling Risers will be used as the guidelines for 

installation, testing and maintenance of the surface and subsea Marine Risers and BOP systems. 

The purpose of these recommended practices is to provide information that can serve as a guide 

for installation and testing of blowout prevention systems Apache has contracted for floating 

marine drilling rigs. 

The goal of using these recommended practices is to assist Apache operations in promoting 

personnel safety, public safety, and integrity of the drilling equipment and preservation of the 

environment for floating marine drilling operations. These recommended practices help to 

facilitate the broad availability of proven, sound engineering and operating practices. 

These practices are considered acceptable for accomplishing BOP and Marine Riser associated 

operations. However, equivalent alternative installations and practices may be utilized to 

accomplish the same objectives. When using these recommended practices or other alternatives, 

Apache will insure that operations comply with requirements of Federal Regulations. 
Apache Deepwater LLC	 	 Page C‐1

Joint Initial Exploration Plan	 	 April 25, 2013

Mississippi Canyon Blocks 554/555 (OCS‐G 34444/34445)	 	

SECTION C 

GEOLOGICAL AND GEOPHYSICAL INFORMATION 

(30 CFR 550.214 and 550.244) 

A. GEOLOGICAL DESCRIPTION 

Proprietary Information 

B. STRUCTURE CONTOUR MAPS 

Proprietary Information

C. INTERPRETED 3-D SEISMIC LINE 

Proprietary Information

D. GEOLOGICAL STRUCTURE CROSS SECTIONS 

Proprietary Information

E. SHALLOW HAZARDS 

A Shallow Hazard Survey was conducted over Mississippi Canyon Blocks 554/555 by 

Geoscience Earth & Marine Services, Inc. (GEMS). The Shallow Hazard Report is being 

submitted to the BOEM in conjunction with this plan. 

F. SITE-SPECIFIC SHALLOW HAZARDS ASSESSMENT 

A Shallow Hazards Assessment was prepared for the proposed surface locations utilizing the 3-D 

seismic exploration data and is included as Attachment C-4.

G. HIGH-RESOLUTION SEISMIC LINES

Proprietary Information

H. STRATIGRAPHIC COLUMN

Proprietary Information

I. TIME VS DEPTH TABLES

Proprietary Information
10615 Shadow Wood Drive, Suite 200 

 Houston, Texas 77043

713.468.1410[o] 713.468.1438 [f] 

www.gemsinc.com 

February 20, 2013 Project No. 0712-2117b 

Apache Deepwater LLC 

2000 W. Sam Houston Parkway South 

Suite 1600 

Houston, TX 77042 

Attention: Mr. John Worthen 

Site Clearance Letter 

Proposed Wellsite MC555-A 

Block 555 (OCS-G-34445) 

Mississippi Canyon Area 

Gulf of Mexico 

Apache Deepwater LLC (Apache) contracted Geoscience Earth & Marine Services, Inc.®, (GEMS) to 

prepare a Site Clearance Letter for the proposed well location in Block 555 (OCS G-34445), Mississippi 

Canyon (MC) Area. This letter addresses specific seafloor and subsurface geologic conditions around 

the proposed location (2,000 ft radius) to the limit of investigation, 4,812 ft below the mudline (bml). 

Apache will drill the proposed MC555-A with a semi-submersible or dynamically positioned (DP) 

semi-submersible. The seabed conditions within an 11,500 ft mooring radius plus an additional 1,000 ft 

buffer zone are discussed to satisfy seabed disturbance guidelines. 

Surface conditions are clear at the proposed wellsite; however, moorings or other seabed disturbance 

activities need to avoid a potential shipwreck, possible unexploded ordnance sites, and potential sites for 

benthic communities. Sandy units with potential for shallow water flow occur at 649 ft bml (585 ft thick) 

and 1,709 ft bml (588 ft thick). 

This letter provides the following details specific to the well location: available data, attachments 

(accompanying the letter), Notice to Lessees (NTL) requirements, man-made features and archaeological 

assessment, wellsite conditions, anchoring considerations, and the conclusions and recommendations. 

Proposed Well Location and Available Data 

The proposed MC555-A surface location lies along the western edge of MC 555 (Figure MC555-A-1). 

Apache provided the following coordinates: 

Proposed Wellsite MC555-A 

Spheroid & Datum: Clarke 1866, NAD27 

Projection: UTM Zone 16 North Line Reference Block Calls 

MC 555 

X: 1,109,157 ft Latitude: 28o 25’ 40.7505” N Inline 15070 357 ft FWL 

Y: 10,320,035 ft Longitude: 88o 39’ 11.9875” W Crossline 13840 7,645 ft FNL 

The details provided in this letter are based on the findings from a geohazard assessment performed by 

GEMS (GEMS, 2012). The report which was submitted to Apache in December, 2012 described the 

geologic and archaeological conditions within the Guadalupe Prospect (in Blocks 554 and 555) and 

vicinity. Apache provided two sets of geophysical data for this assessment: a conventional, 

3-D exploration seismic volume and a high-resolution Autonomous Underwater Vehicle (AUV) data. 

The detailed data specifications are provided in the main report (GEMS, 2012). Well logs and drilling 

reports from the closest existing well (ExxonMobil #1 in MC 555) to the proposed location were also 
Proposed Wellsite MC555-A Clearance Letter 

Apache Deepwater LLC // February 20, 2013

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

FORUM ENERGY TECHNOLOGIES, INC. 

provided by Apache. Integrating these data allowed a thorough analysis of potential drilling hazards 

within the suprasalt stratigraphy at the proposed wellsite. 

Attachments 

The page-size maps and accompanying illustrations were extracted from the available data provided by 

Apache. A maximum anchor radius of 11,500 ft and an additional 1,000 ft buffer zone are included on the 

maps should Apache use a moored rig to drill. The figures embedded within the body text are also 

provided below. 

Map No. MC555-A-1: Bathymetry Map 

 Map No. MC555-A-2: Seafloor Features Map 

Map No. MC555-A-3: Side-Scan Sonar Mosaic 

Map No. MC555-A-4: Geologic Features Map 

Illustration MC555-A-1: Portions of Inline 15070 and Crossline 13840 Showing Conditions Beneath 

Proposed Wellsite MC555-A 

Illustration MC555-A-2: Tophole Prognosis Chart, Proposed Wellsite MC555-A, Mississippi Canyon, 

Block 555 

Illustration MC555-A-3: Potential for Benthic Communities 

Figure MC555-A-1: Regional Rendering of Mississippi Canyon Area, Gulf of Mexico 

Figure MC555-A-2: Power Spectrum Analysis Curve, Proposed Wellsite MC555-A 

Figure MC555-A-3: Seafloor Conditions at the Proposed Wellsite 

Figure MC555-A-4: Suprasalt Stratigraphy between the Proposed Wellsite and ExxonMobil #1 

Figure MC555-A-1. Regional Rendering of Mississippi Canyon Area, Gulf of Mexico 

MC554-A

MC555-A

MC555-B

Grid

North

MISSISSIPPI CANYON

AREA

3 miles

Survey Area

AUV Survey Area

High-potential 

Archaeological Area

Chemosynthetic Area

Shallow Water flow Area

Ordnance Disposal Area

Existing Platform

Existing Well 

Proposed Well Location

Existing Pipeline/

Umbilical

MENSA

Mass-wasting Pathway

Erosional Remnants
Proposed Wellsite MC555-A Clearance Letter 

Apache Deepwater LLC // February 20, 2013

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

FORUM ENERGY TECHNOLOGIES, INC. 

NTL Requirements

The following letter complies with the Bureau of Ocean Energy Management (BOEM) Notice to Lessees 

(NTL’s) 2008-G04, 2008-G05, and 2009-G40, (MMS, 2008a, b and 2010). The requirements set forth in 

NTL 2005-G07 are applicable because the Federal lease block MC 555 is considered to be a high 

probability archaeological block (MMS, 2005 and BOEM, 2011). In compliance with NTL 2005-G07, the 

required archaeological assessment was performed by GEMS and included as an appendix in the main 

report (GEMS, 2012). 

According to NTL 2008-G05 (MMS, 2008b), 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 Apache to illustrate the data parameters 

(Figure MC555-A-2). The power spectrum curve was generated within a 500 ft radius of the intersection 

of the inline and crossline at the proposed wellsite. We converted the amplitude vs. frequency spectrum, 

generated by the SMT software, to power vs. frequency by squaring the amplitude values as described by 

J. A. Coffeen, 1978. 

Figure MC555-A-2. Power Spectrum Analysis Curve, Proposed Wellsite MC555-A 

Man-Made Features and Archaeological Assessment

The surface location is clear of any wells, pipelines, or platforms within a 2,000 ft radius from the 

proposed wellsite. The closest existing well (ExxonMobil #1) is located approximately 1.3 miles southeast 

of the proposed wellsite location in MC 555 (Map MC555-A-1). The well was an exploratory well and is 

currently temporarily abandoned. 

GEMS delineated 23 unidentified side-scan sonar contacts in the digital data within 12,500 ft (11,500 ft 

maximum anchor radius plus 1,000 ft buffer) of the proposed MC555-A (Maps MC555-A-2 and 555-A-3). 

Side-Scan Sonar Contact Number 54 appears to represent a potential shipwreck. The contact is located 

approximately 2.2 miles southeast of the proposed wellsite and a 1,000 ft archaeological avoidance is 

recommended around the contact. No known shipwrecks or objects exist within the area of potential 

effect for the proposed well location. 

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 90 100 110 120

Power (Amp2

)

Frequency (Hz)

POWER SPECTRUM
Proposed Wellsite MC555-A Clearance Letter 

Apache Deepwater LLC // February 20, 2013

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

FORUM ENERGY TECHNOLOGIES, INC. 

None of the other 22 contacts appear to represent cultural resources. Several of the unidentified sonar 

contacts form part of a northeast-southwest trending debris trail in MC Blocks 554 and 598. The debris 

likely represents unexploded ordnance because the designated historic ordnance disposal area lies west 

of the Guadalupe prospect (Figure MC554-A-1). The side-scan sonar contacts within 12,500 ft of the 

proposed wellsite that form part of the debris trail are Side-Scan Sonar Contact Numbers 43, 45-46, 48, 

and 76-78. None of these unidentified side-scan sonar contacts are recommended for archeological 

avoidance or investigation, but Apache should use caution when working near the debris trail because of 

the risk for contact with unexploded ordnance. Other similar contacts along the path of the debris trail 

were identified in the side-scan sonar data, but were not retained in the final contact list. Since these 

contacts were not visible in two or more overlapping swaths of data, it was not possible to verify if the 

contacts represented actual debris or noise in the sonar record. A 100 ft shallow hazard avoidance is 

recommended for the remaining 22 side-scan sonar contacts. 

Table 1. Sonar Contacts Located Within 12,500 ft of MC555-A 

No. Area Block Length 

(ft) 

Width 

(ft) 

Height 

(ft) Shape 

X 

NAD27 

(ft) 

Y 

NAD27 

(ft) 

Avoidance 

Radius (ft) 

19 MC 511 5.44 1.86 0.00 Linear 1112591.97 10329220.90 100 

20 MC 511 14.68 7.23 1.75 Irregular 1112902.20 10329423.85 100 

21 MC 511 35.69 13.33 1.24 Irregular 1112951.32 10329320.37 100 

42 MC 554 12.42 6.58 0.00 Linear 1100325.29 10313357.68 100 

43 MC 554 10.12 2.37 0.00 Linear 1101971.94 10312550.76 100 

44 MC 554 16.49 7.46 0.00 Irregular 1102351.14 10324394.30 100 

45 MC 554 26.64 9.48 0.00 Irregular 1102457.87 10313328.31 100 

46 MC 554 16.93 3.61 0.00 Linear 1102620.96 10313548.00 100 

47 MC 554 13.22 2.94 0.00 Linear 1102642.15 10327125.63 100 

48 MC 554 12.65 4.52 0.00 Linear 1103307.63 10315340.61 100 

49 MC 554 11.29 3.64 0.00 Linear 1104028.27 10311991.31 100 

50 MC 555 11.52 4.74 0.00 Irregular 1112644.89 10312564.17 100 

51 MC 555 10.50 8.70 0.00 Linear 1113273.53 10315889.23 100 

52 MC 555 11.52 2.48 0.00 Linear 1116727.29 10314034.61 100 

53 MC 555 20.24 5.06 0.00 Linear 1118118.76 10326028.12 100 

54 MC 555 42.49 24.57 0.00 Irregular 1119186.80 10314174.41 1,000 

76 MC 598 15.20 3.37 0.00 Linear 1101123.39 10311196.89 100 

77 MC 598 10.12 2.17 0.00 Linear 1101235.39 10311328.45 100 

78 MC 598 9.00 2.18 0.00 Linear 1101247.04 10311266.08 100 

82 MC 598 10.86 2.08 0.00 Linear 1105782.24 10308511.16 100 

83 MC 598 10.86 2.65 0.00 Linear 1106972.13 10311235.93 100 

86 MC 599 17.16 18.29 0.00 Irregular 1110651.55 10309177.14 100 

89 MC 599 15.74 5.94 0.00 Linear 1113261.85 10308889.05 100 

*Blue indicates a recommended archaeological avoidance. 

Wellsite Conditions

The proposed surface location is clear of any constraining seafloor geologic conditions as defined by the 

available geophysical data. MC555-A is expected to intersect a buried fault. The potential for encountering 

significant amounts of shallow gas is low. However, there is a moderate potential for encountering shallow 

water flow within possible overpressured sands. 

Water Depth and Seafloor Conditions

The water depth at the proposed surface location is approximately -4,651 ft and the seafloor slopes 

southeast at less than 2° (Map MC555-A-1). Side-scan sonar data show that the seabed in the vicinity of 

the proposed wellsite is primarily characterized by uniform low reflectivity (Map MC555-A-3). The low 

reflectivity is likely associated with very soft clays. 
Proposed Wellsite MC555-A Clearance Letter 

Apache Deepwater LLC // February 20, 2013

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

FORUM ENERGY TECHNOLOGIES, INC. 

The proposed wellsite MC555-A is located along a relatively shallow mass-wasting pathway trending 

northwest-southeast across the Survey Area (Figure MC555-A-1 and Map MC555-A-2). The hummocky 

topography within the vicinity of the proposed location represents the seafloor expression of buried slumps. 

The slumps are buried by more than 100 ft of strata (Figure MC555-A-3, GEMS, 2012). Mound-like 

features in the same area are associated with rafted blocks within the mass-transport deposits (MTD) matrix 

and are not hydrocarbon related (GEMS, 2012). A drainage feature (gully) located approximately 348 ft to 

the northwest suggests low-level sediment transport activities in the recent geologic past (> 10,000 yrs), 

(Figure MC555-A-1). 

Figure MC555-A-3. Seafloor Conditions at the Proposed Wellsite 

Deepwater Benthic Communities 

BOEM and BSEE did not designate Federal lease Block MC 555 as having high-density deepwater 

benthic communities (MMS, 2010). There are no apparent geophysical indicators at the seafloor or at 

depth that would suggest conditions capable of supporting significant deepwater benthic communities 

within 2,000 ft of the proposed wellsite (Maps MC555-A-2 and 555-A-3). 

Stratigraphy 

Stratigraphic conditions are shown on Illustrations MC555-A-1 and 555-A-2. The lithology at the 

proposed wellsite was inferred by integrating the seismic facies with the well log response at the existing 

well, ExxonMobil #1. Generally, the suprasalt seismic facies were correlated across both locations; 

however, the sand-prone channel system observed within Unit 4 at ExxonMobil #1 is absent at the 

proposed location (Figure MC555-A-4). The sediments below the seafloor to the limit of investigation 

(4,812 ft bml or -9,463 ft bsl) consist primarily of hemipelagic clays, muddy- to sand-prone turbidites, 

slope fan deposits, and mass-transport deposits. 

The shallow stratigraphy (Seafloor to Horizon 10, Unit 1) is interpreted to be hemipelagic clay- to silt-rich 

sediments down to approximately 200 ft bml. The sediment units between Horizon 10 and Horizon 30 

(Units 2 and 3) are dominated by mass-transport deposits (MTD) with intermittent silty- to sandy turbidites 

to approximately 1,234 ft bml. Sand-prone erosional remnants from older strata are possible within the 

MTD matrix. Unit 3 is associated with a regional basin-floor fan system known as the “Blue Unit” (GEMS, 

2012). The low gamma ray log response (inferring sand) at ExxonMobil #1 suggests that there is a high 

Portion of AUV Line 131

Seafloor expression of 

rafted block

500 ft

Assumed velocity: 5,000 ft/sec

W E

Two-way travel time (secs)

Horizontal

Distance (ft)

Proposed Wellsite 

MC555-A

Weakly stratified 

INDEX MAP

AUV Line 131

Seafloor 

expression of 

rafted blocks

Grid

North

MC 554

1,000 ft

Buried slump

MC555-A 

MC 555

Circle represents

2,000 ft radius around

proposed wellsite

Gully

10 ft

Mound-like features at the seabed

represent the seafloor expression of

rafted blocks within buried slumps.

The slumps are buried by more than

100 ftof strata.

The lack of direct hydrocarbon

indicators (DHI) at these sites confirm

that the features are not hydrocarbon

related. See the main report for more

details (GEMS, 2012).

MC 554 MC 555

Seafloor Rendering

Amorphous layer

Well-layered 

unit

Shallow strata comprises of

hemipelagic clay- to silt-rich

sediments.
Proposed Wellsite MC555-A Clearance Letter 

Apache Deepwater LLC // February 20, 2013

Geoscience Earth & Marine Services, Inc. ® // 6 

FORUM ENERGY TECHNOLOGIES, INC. 

potential for sandy turbidites within the Blue Unit between 649 ft bml and 1,234 ft bml 

(Figure MC555-A-4). 

Remnants of a sand-prone slope fan system occur in the middle portion of Unit 4 (Horizon 30 to 

Horizon 40). A vertical borehole at the proposed location will intersect the slope fan sediments from 

approximately 1,709 ft bml to 2,297 ft bml. The upper portion of the strata (between 1,234 ft bml to 1,709 

ft bml) comprises of mud-dominated turbidites, while the lower portion (between 2,297 ft bml to 2,620 ft 

bml) comprises of mud-dominated rotated slide blocks and silt- to sand-prone turbidites. The underlying 

strata, Unit 5 (Horizon 40 to the limit of investigation) comprises of muddy- to sandy turbidites and 

possibly MTDs. Thick, continuous sand layers are possible within this sediment unit (between 2,620 ft 

bml and 4,812 ft bml), Figure MC555-A-4. 

Figure MC555-A-4. Suprasalt Stratigraphy between the Proposed Wellsite and ExxonMobil #1 

Faults 

No seafloor faults will be encountered at the proposed wellsite location (Map MC555-A-2). However, a 

vertical wellbore at proposed wellsite MC555-A will penetrate a buried fault at approximately 2,297 ft bml 

(-6,948 ft bsl), Illustrations MC555-A-1 and 555-A-2. The fault is downthrown northwest towards the 

wellbore and is buried by up to 1,600 ft of sediments. 

Shallow Gas and Shallow Water Flow 

The scout tickets from ExxonMobil # 1 did not report any shallow geohazard conditions related to shallow 

water flow and/or shallow gas. As a result, significant shallow gas is not expected at the proposed 

wellsite; however, a moderate potential for shallow water flow is possible within the identified sand prone 

sequences (Illustration MC555-A-2). 

INDEX MAP

Seafloor Rendering

Grid

North

MC 554

2,000 ft

MC555-A 

Circle represents 2,000 ft 

radius around proposed 

wellsite

ExxonMobil #1

MC 555

MC 599

Two-way travel time (secs)

Horizontal

Distance (ft)

Proposed Wellsite 

MC555-A ExxonMobil #1

MC 554 MC 555 MC 599

Arbitrary Line A-A`

5,000 ft NW SE

Seafloor

Horizon 10

Horizon 20

Horizon 30

Limit of 

Investigation

GR R

GR - Gamma Ray

R - Resistivity

Generally, the suprasalt stratigraphy at the

existing well location (ExxonMobil #1) and

the proposed wellsite MC555-A is similar. The

main difference observed is within Unit 4

where only remnants of the slope fan system

exist at the proposed location.

The 22” casing got stuck and was later jarred

free at ExxonMobil #1. The casing was stuck

in possibly clay-prone sediments within the

channel system in Unit 4. Relative Amplitude

Low High

UNIT 1

UNIT 2

UNIT 3

UNIT 4

UNIT 5

Horizon 40

Channel

Blue 

Unit

22” casing stuck
Proposed Wellsite MC555-A Clearance Letter 

Apache Deepwater LLC // February 20, 2013

Geoscience Earth & Marine Services, Inc. ® // 7 

FORUM ENERGY TECHNOLOGIES, INC. 

Shallow Gas. There are no apparent subsurface high-amplitude anomalies directly below the proposed 

location (Map MC555-A-4). Slightly elevated amplitude responses near the buried fault (within Unit 4) 

suggest minor amounts of biogenic gas accumulation within the unit (Illustration MC555-A-2). 

The amplitudes are however, buried by up to 1,700 ft of sediments and there is no geophysical evidence 

that suggests fluid migration from depth to shallower sediments. There is a low potential for encountering 

significant accumulation of shallow gas within these sand-prone slope fan sediments as well as within 

possible sand layers between 649 ft bml to the limit of investigation (4,812 ft bml). The potential for 

encountering shallow gas is considered negligible in the clay-prone unit between the Seafloor and 

649 ft bml. 

Shallow Water Flow. There is a moderate potential for encountering overpressured sands within the 

Blue Unit, Unit 3 (649 ft bml to 1,234 ft bml) and the underlying slope fan system (1,709 ft bml to 2,297 ft 

bml), Illustration MC555-A-2. Although, numerous wells in the Mississippi Canyon Area have 

experienced water flow within the Blue Unit, no such occurrence was reported at ExxonMobil #1. 

Potential overpressures may have been mitigated while drilling the well, and hence not reported. 

A low potential for shallow water flow is interpreted between 1,234 ft bml to 1,709 ft bml and beneath 

2,297 ft bml. The shallow, clay-rich sediments (Seafloor to 649 ft bml) are considered to have a negligible 

potential for shallow water flow. 

Anchoring Considerations

The 11,500 ft radius outlined on the accompanying maps represents the area of potential effect for 

anchoring. An additional 1,000 ft buffer zone is also included. The following discussions address the 

seafloor conditions related to anchoring considerations within the total 12,500 ft radius. 

Water Depth and Seafloor Conditions

Water depths within the potential mooring area range from about -4,453 ft to -4,868 ft (Map MC555-A-1). 

The seafloor slopes southeast with shallow water depths in the western portion of the mooring radius. 

Seafloor gradients within the mooring radius range from nearly flat to approximately 42° (GEMS, 2012). 

Most of the seafloor has low gradients (less than 3°). 

Irregular seafloor morphology within the potential mooring area is associated with erosion-related features 

(e.g. gullies and erosional scarps) and seep-related features (e.g. mounds and pockmarks), 

Map MC555-A-2. The hummocky seafloor across most of the remaining area represents shallow buried 

slumps and the mound-like features within the slumps represent buried rafted blocks (Figure MC555-A-3). 

Seafloor slopes associated with the erosion-related and seep-related features range from 5° to 13° 

(GEMS, 2012).

Seafloor faulting is located in the northeastern portion of the radius in central MC 555. The faults trend 

northeast-southwest, are downthrown mainly to the northeast, and bound the expulsion features. 

Seafloor offsets associated with the faults are up 50 ft with associated slopes reaching 42°. 

Deepwater Benthic Communities 

The expulsion features that exhibit high backscatter reflectivity and “rocky” topography on sonar data are 

likely associated with carbonate hard grounds (conditions conducive for benthic communities), Map 

MC555-A-3 and Illustration MC555-A-3. These expulsion features have a high potential for supporting 

densely populated benthic communities and are shown as orange polygons on Map MC555-A-2. 

The features lacking irregular topography but still exhibit high backscatter and sonar reflectivity represent 

limited hard ground areas. These sites have a lower potential for supporting seep communities and are 

shown as green polygons on Map MC555-A-2. 

BOEM requires at least a 250 ft buffer around potential benthic community sites for all proposed seafloor 

disturbances (including those caused by anchors and anchor chains), MMS, 2010. However, if seafloor 

disturbances occur within 500 ft of these sites, Apache is required to submit an as-placed anchor plat to 

BOEM. We recommend conducting an ROV investigation to confirm or deny the existence of deepwater 
Proposed Wellsite MC555-A Clearance Letter 

Apache Deepwater LLC // February 20, 2013

Geoscience Earth & Marine Services, Inc. ® // 8 

FORUM ENERGY TECHNOLOGIES, INC. 

benthic communities at the potential hard grounds if these areas occur near the proposed anchors or 

anchor chains. 

Conclusions and Recommendations

We appreciate the opportunity to be of service to Apache and look forward to working with Apache on 

future projects. The conclusions and recommendations from this assessment are as follows: 

Wellsite Conditions 

No major seafloor hazards or constraints are defined by the available data within 2,000 ft radius of the 

proposed location. Caution and possible mitigation is recommended when encountering potential 

overpressured sands between 649 ft bml to 1,234 ft bml, and 1,709 ft bml to 2,297 ft bml. 

Anchor Maximum Radius Conditions 

The potential seafloor constraints within the mooring radius include possible hard grounds that could 

support benthic communities, a potential shipwreck, and possible unexploded ordnance sites. 

A minimum of a 250 ft radius is recommended around the potential benthic communities’ sites. Other 

recommendations include, a 1,000 ft archaeological avoidance around Side-Scan Sonar Contact Number 

54, and a 100 ft shallow hazard avoidance for the remaining 22 side-scan sonar contacts. Care should 

be taken near the debris trail of potential unexploded ordnance in MC 554 and 598. All operations must 

cease and BOEM notified within 48 hours should any potentially historic materials such as textiles, wood, 

ceramics, or other items be uncovered during operations in the area. 

Sincerely, 

GEOSCIENCE EARTH & MARINE 

SERVICES, INC.®

Oluwayomi Oyedele Daniel Lanier 

Geoscientist Vice President-Geosciences 

Erin Williams Janes 

Project Manager/Senior Geoscientist 

Attachments (4 Maps and 3 Illustrations) 

Distribution: 

Mr. John Worthen, Apache Deepwater LLC (3 copies) 

REFERENCES 

Bureau of Ocean Energy Management, 2013, ASCII Data Files, published on the BOEM Gulf of Mexico Region 

Homepage, <http://www.gomr.boem.gov/homepg/pubinfo/freeasci/freedesc.html>, accessed January, 2013. 

Bureau of Ocean Energy Management, 2012, Seismic Water Bottom Anomalies Map Gallery, published on the 

BOEM Homepage, <http://www.boem.gov/Oil-and-Gas-Energy-Program/Mapping-and-Data/Map-Gallery/SeismicWater-Bottom-Anomalies-Map-Gallery.aspx>, accessed November, 2012. 

Bureau of Ocean Energy Management, 2011, 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), Revisions to the list of OCS lease 
Proposed Wellsite MC555-A Clearance Letter 

Apache Deepwater LLC // February 20, 2013

Geoscience Earth & Marine Services, Inc. ® // 9 

FORUM ENERGY TECHNOLOGIES, INC. 

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 Region (GOMR), NTL 2011-

JOINT-G01. Effective Date December 29, 2011. 

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

Geoscience Earth & Marine Services, Inc.®

 (GEMS), 2012, Geohazard assessment, Guadalupe Prospect, blocks 554 

and 555, Mississippi Canyon Area, Gulf of Mexico, Project No. 0712-2117b. 

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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.