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-09626

Type - Initial Exploration Plan

Lease(s) - OCS-G33323 Block - 621 Lloyd Area

Operator - Anadarko Petroleum Corporation

Wells A and B

DP SEMISUBMERSIBLE

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

should be addressed in an Environmental Assessment.

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

Chiquita Hill

Plan Coordinator

Description -

Rig Type -

Subject:

From:

April 25, 2012
INITIAL EXPLORATION PLAN (N-9626) 

ANADARKO PETROLEUM CORPORATION 

LLOYD RIDGE BLOCK 621 

OCS-G 33323 

PUBLIC COPY 

RECORD OF CHANGE LOG 

Submission 

Type 

Date Sent to 

BOEM 

Summary of Submission Page 

Numbers 

Initial 1/31/2012 EP submittal. All 

Amendment 2/1/2012 Submitted payment receipt for Initial EP from pay.gov for 

BOEM records. No EP changes at that time. 

N/A 

Amendment 3/8/2012 Submitted seismic data via USB per BOEM request. N/A 

Final Copy of 

Plan 

4/11/2012 Complete EP Submittal. 

Revised Oil Spill Information in Section H, and Section N, to 

include approval date for Sub-Regional OSRP. Updated CGA 

and MSRC overview paragraph in Section H. 

All, 

51-52 (H), 

108, 119 (N) 

Add Record of 

Change Log 

4/11/2012 Add Record of Change Log Cover (1) 
 

PUBLIC 

INITIAL EXPLORATION PLAN 

LLOYD RIDGE BLOCK 621 

OCS-G 33323 

OFFSHORE, ALABAMA

 

Anadarko Petroleum Corporation 

1201 Lake Robbins Drive 

The Woodlands, Texas 77380 

Contact: Bridget O’Farrell 

Bridget.OFarrell-Villarreal@anadarko.com 

(832) 636-1694 

1 – Hard Copy Confidential 

1 – CD Confidential 

1 – Hard Copy Public Information 

1 – CD Public Information

January 2012 
 

INITIAL EXPLORATION PLAN 

LEASE OCS-G33323 

Lloyd Ridge Block 621 

 A. Plan Contents 

 B. General Information 

 C. Geological, Geophysical 

D. Hydrogen Sulfide Information 

 E. Biological, Physical and Socioeconomic Information 

F. Wastes and Discharge Information 

 G. Air Emissions Information 

 H. Oil Spill Information 

I. Environmental Monitoring Information 

 J. Lease Stipulations 

 K. Support Vessels and Aircraft Information 

 L. Onshore Support Facilities Information 

M. Coastal Zone Management Act Information 

N. Environmental Impact Analysis 

O. Administrative Information 
 

A 

PLAN CONTENTS

(a) Plan Information Form 

Under this Initial Exploration Plan, Anadarko Petroleum Corporation (Anadarko) proposes to 

drill and complete two wells. Both wells will be in Lloyd Ridge Block 621. The wells will be 

drilled using either a dynamically positioned (DP) drillship or a DP semi-submersible drilling 

rig. Drilling and completion operations for all well locations will utilize a Subsea BOP stack. 

OCS Plan Information Form MMS-137 is enclosed as Attachment A-1. 

(b) Location 

Enclosed as Attachment A-2 is a well location plat at a scale of 1 inch = 2,000 feet that depicts 

the surface locations and water depth of the proposed wells. 

(c) Safety and Pollution Prevention Features 

Safety features on the drilling rig will include well control, pollution prevention, safe welding 

procedures, and blowout prevention equipment as described in Title 30 CFR Part 250, Subparts 

C, D, E, G and O; and as further clarified by BOEM/BSEE Notices to Lessees, and applicable 

regulations of the Environmental Protection Agency and the U.S. Coast Guard. The appropriate 

life rafts, life jackets, ring buoys, etc., as prescribed by the U.S. Coast Guard, will be maintained 

on the facility at all times. 
 

(d) Storage Tanks and Production Vessels 

The proposed wells will be drilled with a DP drillship or a DP semi-submersible rig. 

Type of Facility Type of 

Storage Tank 

Tank 

Capacity 

Number 

of Tanks 

Total 

Capacity 

Fluid 

Gravity 

(API) 

Total 

Capacity of 

all Tanks for 

Rig Type 

Drillship Fuel Oil Storage 

Tank 

16,564 bbls 1 16,564 bbls No. 2 Diesel 6 tanks total= 

36,595.9 bbls 

 Fuel Oil Storage 

Tank 

16,685.5 bbls 1 16,685.5 bbls No. 2 Diesel 

 Fuel Oil Settling 

Tanks 

836.6 bbls 2 1,673.2 bbls No. 2 Diesel 

 Fuel Oil Day 

Tanks 

836.6 bbls 2 1,673.2 bbls No. 2 Diesel 

DP Semi-submersible Fuel Oil Hull 

Tanks 

4,541 bbls 2 9,082 bbls No. 2 Diesel 7 tanks total= 

16,689 bbls 

 Fuel Oil Hull 

Tanks 

3,392 bbls 2 6,784 bbls No. 2 Diesel 

 Fuel Oil Deck 

Day Tank 

629 bbls 1 629 bbls No. 2 Diesel 

 Fuel Oil Deck 

Settling Tank 

164 bbls 1 164 bbls No. 2 Diesel 

 Fuel Oil 

Emergency 

Generator 

30 bbls 1 30 bbls No. 2 Diesel 

(e) Pollution Prevention Measures 

The drilling rig utilized for these operations will comply with all applicable regulations regarding 

pollution prevention and control. The rig has a Shipboard Oil Pollution Emergency Plan 

(SOPEP), which is reviewed and approved annually by the American Bureau of Shipping (ABS). 

The SOPEP is provided to assist employees in dealing with an unexpected discharge of oil. Its 

primary purpose is to set in motion the necessary actions to stop or minimize the discharge of oil 

and to mitigate its effects. Effective planning ensures that the necessary actions are taken in a 

structured, logical and timely manner. 
 

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

areas to collect contaminants and debris during routine operations and/or rainfall. Most deck 

drains and some of the joints at the edge of the rig floor go overboard or into the moonpool, 

respectively. To prevent ocean discharge from the drains there is a dedicated drip pan under the 

rotary table. The pipe racks, mud pump room, sack store, and drill floor drains go to a holding 

tank, which is served by a dedicated oily water separator. The well test area, engine room, and 

other major machinery spaces drains all go to slops tanks, which are served by a large generalservice, oily water separator. The containment devices are temporary. They are not meant for 

permanent storage of waste. On the rare occasion that they contain wastes, they are pumped, 

mopped, or cleaned within a short period of time. The chances of damage to a containment 

structure during such time as it contains wastes are exceedingly small. 

The discharge of oils and greases during rainfall and/or routine operations will be localized in the 

vicinity of the drillsites and should not have any effects on Florida lands, waters, or wildlife due 

to the proximity to shore and prevention measures. 

(f) Additional Measures

Anadarko proposes additional measures for safety, pollution prevention, and early spill detection 

beyond those required by 30 CFR 250, as outlined in Anadarko’s Sub-Regional Oil Spill 

Response Plan. These additional measures include: 

 Shipboard Oil Pollution Emergency Plan 

 Operations Manual 

 Spill Prevention Control and Countermeasures (SPCC) Plan 

General procedures for fuel transfers, well control and drilling programs are detailed in the SubRegional Oil Spill Response Plan.

(f) Description of Previously Approved Lease Activities 

Anadarko has no previously approved well locations in Lloyd Ridge Block 621. 
MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) Page 1 of 3 

U.S. Department of the Interior 

Minerals Management Service OCS PLAN INFORMATION FORM 

OMB Control Number: 1010-0051 

OMB Approval Expires: 12/31/2011 

General Information 

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

Company Name: Anadarko Petroleum Corporation MMS Operator Number: 00981 

Address: 1201 Lake Robbins Drive Contact Person: Bridget O’Farrell 

 The Woodlands, TX 77380 Phone Number: (832) 636-1694 

 E-Mail Address: Bridget.OFarrell-Villarreal@anadarko.com 

Lease(s): OCS-G 33323 Area: LL Block(s): 621 Project Name (If Applicable): Kingpin 

Objective(s): x Oil x Gas Sulphur Salt Onshore Base: Fourchon, LA Distance to Closest Land (Miles): 143 

Description of Proposed Activities (Mark all that apply) 

x Exploration drilling Development drilling 

x 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 

x 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 x No 

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

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

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

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

Tentative Schedule of Proposed Activities 

Proposed Activity Start Date End Date No. of Days 

Drill and complete Location A 04/01/2013 06/15/2013 75 

Drill and complete Location B 06/16/2013 08/30/2013 75 

 

 

 

 

Description of Drilling Rig Description of Production Platform 

Jackup x Drillship Caisson Tension leg platform 

Gorilla Jackup Platform rig Well protector Compliant tower 

 Semisubmersible Submersible Fixed platform Guyed tower 

x 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) 

 
MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) Page 2 of 3 

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): 

A 

Subsea Completion 

Anchor Radius (if applicable) in feet: 

N/A x Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. 

OCS-G 33323 

Area Name 

Lloyd Ridge 

Block No. 

621 

Blockline 

Departures 

(in feet) 

N/S Departure: 1,512' FSL N/S Departure: F L 

E/W Departure: 3,212' FWL E/W Departure: F L 

Lambert X-Y 

coordinates X: 1,412,971' X: 

Y: 9,917,350' Y: 

Latitude/ 

Longitude Latitude: 27.3282111 Latitude: 

Longitude: -87.7007611 Longitude: 

 TVD (Feet): MD (Feet): Water Depth (Feet): 9,089' 

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 = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.197. An 

agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays 

a currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public 

reporting burden for this form is included in the burden for preparing Exploration Plans and Development Operations 

Coordination Documents. We estimate that burden to average 600 hours per response, or 640 with an accompanying EP 

(1,000 hours in AKOCSR), or 690 (1,700 in AKOCSR) with an accompanying DPP or DOCD, including the time for 

reviewing instructions, gathering and maintaining data, and completing and reviewing the forms associated with subpart B. 

Direct comments regarding the burden estimate or any other aspect of this form to the Information Collection Clearance 

Officer, Mail Stop 5438, Minerals Management Service, 1849 C Street, NW., Washington, DC 20240.
MMS FORM MMS-137 (December 2008 - Supersedes all previous editions of form MMS-137 which may not be used.) Page 3 of 3 

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): 

B 

Subsea Completion 

Anchor Radius (if applicable) in feet: 

N/A x Yes No 

Surface Location Bottom-Hole Location (For Wells) 

Lease No. 

OCS-G 33323 

Area Name 

Lloyd Ridge 

Block No. 

621 

Blockline 

Departures 

(in feet) 

N/S Departure: 3,611' FSL N/S Departure: F L 

E/W Departure: 2,314' FWL E/W Departure: F L 

Lambert X-Y 

coordinates X: 1,412,075' X: 

Y: 9,919,452' Y: 

Latitude/ 

Longitude Latitude: 27.3339806 Latitude: 

Longitude: -87.7035583 Longitude: 

 TVD (Feet): MD (Feet): Water Depth (Feet): 9,087' 

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 = 

Paperwork Reduction Act of 1995 Statement: The Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35) requires us 

to inform you that MMS collects this information as part of an applicant’s Exploration Plan or Development Operations 

Coordination Document submitted for MMS approval. We use the information to facilitate our review and data entry for 

OCS plans. We will protect proprietary data according to the Freedom of Information Act and 30 CFR 250.197. An 

agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays 

a currently valid Office of Management and Budget Control Number. The use of this form is voluntary. The public 

reporting burden for this form is included in the burden for preparing Exploration Plans and Development Operations 

Coordination Documents. We estimate that burden to average 600 hours per response, or 640 with an accompanying EP 

(1,000 hours in AKOCSR), or 690 (1,700 in AKOCSR) with an accompanying DPP or DOCD, including the time for 

reviewing instructions, gathering and maintaining data, and completing and reviewing the forms associated with subpart B. 

Direct comments regarding the burden estimate or any other aspect of this form to the Information Collection Clearance 

Officer, Mail Stop 5438, Minerals Management Service, 1849 C Street, NW., Washington, DC 20240.
621

LL 621 A

LL 621 B

 Scale:1"=2,000' By: KAA Date: 20/Oct/10

LL 621

OCS - G-33323

Bathymetry Map

Public Location and

 621-A SFL 1,512' FSL 3,212' FWL 1412971 9917350 27.3282111 -87.7007611 -9,089'

Well Loc. Footages X Y Lat. Long. Water Depth

 621-B SFL 3,611' FSL 2,314' FWL 1412075 9919452 27.3339806 -87.7035583 -9,087'

-9100

-9100

-9060 -9070

-9090

-9080

-9090 -9090

-9090
 

B 

GENERAL INFORMATION 

(a) Applications and Permits 

Prior to beginning exploration operations the following application(s) will be submitted for 

approval: 

Application/Permit Issuing Agency Status 

Permit to Drill Bureau of Safety and Environmental 

Enforcement (BSEE) 

To be submitted 

(b) Drilling Fluids 

Type of Drilling Fluid Estimated Volume Per Well 

Water-based (NaCl saturated, seawater, 

freshwater, barite) for Pump and Dump 

20,000 bbls of 16.3 ppg per well 

Synthetic-based (internal olefin, ester) 13,000 bbls per well 

Oil-based N/A 

(c) Oils Characteristics 

Oil will not be produced under this Initial Exploration Plan. Therefore the oils characteristics 

information is not required per NTL 2008-G04 2(d). 

(d) New or Unusual Technology 

Anadarko does not propose to use any new or unusual technology to drill the wells proposed in 

this plan. 

(e) Bonding Statement 

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

area-wide bond furnished and maintained according to 30 CFR Part 556, subpart I; NTL No. 

2000-G16, “Guidelines for General Lease Surety Bonds,” and National NTL No. 2008-N07, 

“Supplemental Bond Procedures”. 

(f) Oil Spill Financial Responsibility (OSFR) 

Anadarko Petroleum Corporation (Company Number 00981) has demonstrated oil spill financial 

responsibility for the facilities proposed in this EP according to 30 CFR Part 553, and NTL No. 

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

(g) Deepwater Well Control Statement 

Anadarko Petroleum Corporation (Company Number 00981) has the financial capability to drill 

a relief well and conduct other emergency well control operations if required. 

(h) Blowout Scenario

Anadarko prepared this blowout scenario pursuant to guidance provided in NTL No. 2010-N06. 

Lloyd Ridge Block 621 Well #1 (Location “A”) under this Initial EP has been determined to 

have the highest worst-case discharge rate and was utilized for the following blowout scenario. 

Based on NTL No. 2010-N06 guidance, the maximum hydrocarbon discharge is calculated to be 

627 bopd (condensate). 

Purpose 

This overview provides a generic blowout scenario, additional information regarding any 

potential oil spill, and the measures Anadarko will take to prevent a blowout and if necessary, 

promptly respond to manage a blowout scenario if one occurs. The following information is 

pursuant with 30 CFR 550.213(g), 550.219, 550.250 and NTL No. 2010-N06. 

Background 

The Lloyd Ridge 621 #1 (Location “A”) will be drilled as an exploratory well in Lloyd Ridge 

Block 621. Geological and Geophysical Information is included in Section C. This information 

has been developed to document the additional information requirements for Exploration Plans 

as requested by NTL No. 2010-N06. 

Information Requirements 

Blowout Scenario 

The Lloyd Ridge Block 621 #1 (Location “A”) well is to be drilled utilizing a MODU rig, marine 

riser, and a sub-sea BOP. A typical casing program will be used including a wellhead system, 

surface casing, and an intermediate casing in order to reach the planned total depth. 

The blowout scenario assumes that a hydrocarbon influx occurs, followed by a well control event 

from the objective sands. The sub-sea BOP and marine riser subsequently fails and a blow-out at 

the seabed occurs. The worst case discharge (WCD) scenario assumes 12.25" open hole with a 

13-5/8" intermediate string per the included wellbore schematic. The WCD assumes the 

objective is exposed and able to flow hydrocarbon. 
 

Estimated flow rate of the potential blowout: 

Category Initial EP 

Type of Activity Exploration Drilling 

Facility Location (area/block) LL 621 

Facility Designation #1 (Location “A”) 

Distance to Nearest Shoreline (miles) 143 miles 

Uncontrolled blowout (volume per day) 627 bbls 

Type of Fluid(s) Condensate 

a) Potential for the well to bridge over 

Mechanical collapse of the reservoirs in the open-hole section of the wellbore was not 

considered. 

b) Measures to enhance the ability to conduct effective and early intervention in 

the event of a blowout 

The likelihood of surface intervention to stop a blowout is high and is based on the 

following equipment specific to the MODU that has been, or will be, contracted to do 

this drilling program: 

 ROV Secondary BOP Control System: The BOP is to be confirmed to 

have a ROV Intervention Panel and circuits that have the following 

attributes:

 Hot stab is capable of closing one set of: 

 Blind-Shear Rams – One Set

 Pipe Rams – One Set

 Unlatch the Lower Marine Riser Package

 Hot stab to be function tested in conjunction with the Stump test 

and tested at the same rate and pressure as the pump installed on 

the ROV used by the rig. 

The panels can also be operated by an ROV from an independent 

supply boat in the event of a loss of rig scenario. 

 Deadman / Autoshear function: The rig is equipped with an automated 

sequence that closes the blind shear rams in the event of any of the 

following scenarios:

 Inadvertent disconnect of the LMRP 

 Loss of both hydraulic pressure and electrical supply from the 

surface BOP control system 

 No human interface is required once these systems are armed. 
 

c) Availability of a rig to drill a relief well 

Per the preliminary Mutual Aid agreements that are being worked between E&P 

Operators in the Gulf of Mexico, Anadarko will select from the best rig option available 

in the Gulf of Mexico fleet if and when it is required for relief well work. 

As of 1/25/2012, there are 11 rigs capable of operating under these conditions in the Gulf 

of Mexico. A rig which could be used to drill a relief well is the Discoverer Clear 

Leader, which is a dynamically positioned drillship capable of operating in the water 

depths and drilling to the total well depths associated with a relief well for this project. 

This rig is currently under contract with Chevron and is on location in Walker Ridge 

Block 758. 

There are no nearby platforms from which to drill a relief well. It is not feasible to drill a 

relief well from land. 

d) Rig package constraints 

A rig capable of drilling in 9,200' of water with a 15k stack is required for any relief well 

operations. 

e) Time taken to mobilize a rig and drill a relief well 

An estimate of 7-21 days is required to suspend operations on a deepwater GOM well 

and begin drilling the relief well. This assumes 0-14 days to suspend current operations 

on an existing well and 7 days to mobilize and be ready to spud the relief well. The 

estimated time to drill the relief well is 48 days for an estimated total of 55-69 days from 

time of blowout to completion of relief well. 

The time estimate provided for the plan well is inclusive of 'both' drilling 'and' 

completion operations. As a completion is not typically part of relief well operations no 

time has been included for completion operations in the relief well estimate. Therefore 

the estimated time for a relief well could potentially be less than for the plan well. In 

addition, information and learning from the drilling of the original well may provide 

opportunities to optimize drilling performance for relief well operations and thus reduce 

the required drilling time. 

f) Assumptions and calculations used in EP and approved or proposed Oil Spill 

Response Plan (OSRP) 

EP–Lloyd Ridge Block 621 #1 (Location “A”) 

 Nodal analysis was performed to calculate worst case discharge volumes. The 

WCD for the Lloyd Ridge Block 621 #1 (Location “A”) is 627 bbls of 

condensate per day.
 

 The maximum total volume during a blowout could potentially be 43,263 bbls 

assuming 69 days for the maximum duration of a blowout, multiplied by the worst 

case daily uncontrolled blowout volume of 627 bbls of condensate per day. 

 Lloyd Ridge Block 621 #1 (Location “A”) is anticipated to be a dry natural gas 

well, all gas will be either naturally evaporated or flared at surface. 

Sub-Regional OSRP–DeSoto Canyon Block 490 Location “C” 

 Gemini Solutions “Merlin and Avalon” software was used to estimate the WCD 

for Desoto Canyon Block 490 Location “C”. The WCD was calculated to be 

347,431 bbls of crude oil per day. Copies of the nodal and reservoir models 

were submitted electronically via CD for the WCD wells with the associated 

Supplemental EP (Control #: S-7533). 

 At the seafloor, the estimated worst case discharge used for the well is 347,431 

bopd (crude) based on the objective interval. 

 The maximum total volume during a blowout could potentially be 31,616,221

bbls assuming 91 days for the maximum duration of a blowout, multiplied by the 

worst case daily uncontrolled blowout volume of 347,431 bopd (crude). 

g) Measures taken to reduce the likelihood of a blowout 

 Well design: Anadarko utilizes a systematic well design process for the planning 

and construction of a well operation. This process taps into the depth of 

experience Anadarko possesses in the deepwater arena and involves a multidisciplinary team peer review of the well design, shallow hazards and formation 

pressure hazards expected during the drilling phase of the well. This process 

minimizes the potential for an unplanned well control event that could lead to a 

blowout. This process will also, by law, include a Professional Engineer review 

and approval of the final casing design and cementing program. 

A detailed pre-drill assessment of formation pressure provided by Anadarko’s 

Geologic/Geophysics team along with 3rd party consultants for real-time updates allow 

for a mud program that provides an overbalanced mud weight for the safe drilling of the 

well. For an exploration well this may also include taking formation pressures to confirm 

the actual formation pressure during the well construction process and minimize the risk 

of an unplanned well control event. The pore pressure environment in the Lloyd Ridge 

Block 621 well is understood due to the nearby offset well, the Lloyd Ridge Block 400 

#001. 

The well construction process also requires a systematic review and management 

acceptance of the start-up preparation work for the rig and crews and the third party 

technical audit work on the rig and the rig’s well control equipment. This measures the 

rig’s ability to handle an unplanned well control event and provide assurance that the rig 

can successfully mitigate a loss of well control event and prevent it from becoming a 

blowout scenario. 
 

 Barrier Philosophy: For all well designs, Anadarko requires and uses a redundant 

barrier philosophy, that being two independent barriers for both internal and external 

flow paths in the final wellbore. It is also standard practice to conduct pressure testing, 

in accordance with the law, to confirm integrity on all relevant barriers. In addition, all 

intermediate and production casings returned to the wellhead will be locked down 

before proceeding with subsequent wellbore construction. 

 BOP and well control equipment: The rig will have an 18-3/4" 15k psi BOP with 

primary and secondary BOP control systems. The BOP will have been completely 

recertified compliant to OEM specifications, by a qualified 3rd Party. Prior to 

commencement of operations at the Lloyd Ridge Block 621 location, an independent 

third party verification will be obtained that the subsea BOP is designed for the specific 

equipment on the rig and this specific well design 250.416(f) 

 BOP and well control equipment testing: To ensure effectiveness of the BOP and 

well control equipment, a testing program will be conducted prior to running the BOP 

and then during the well operations at the Lloyd Ridge Block 621 well. This testing 

program will be compliant with current federal regulations for pressure and function 

testing and will also provide periodic assessment on the performance of both primary 

and secondary BOP control systems including actual interface operations with the ROV 

and the ROV panel. 

 Well control training and drills: Anadarko requires that key nominated onshore and 

offshore positions including rig contractor personnel hold a WellCAP or equivalent 

well control training certificate, renewable every two years for the type of floating 

drilling operation being conducted. Anadarko also monitors compliance of its 

personnel with the applicable federal regulations, including those found in 30 CFR Part 

250 Subpart O. 

A comprehensive program of well control drills will be conducted offshore to ensure 

readiness to identify and then manage a well control situation and thereby minimize the 

potential for a well control event to lead to a blowout scenario. 

h) Arrangements for drilling a relief well 

 Anadarko maintains a master agreement with Wild Well Control for advice, 

management, engineering, well kick pre and post modeling and resource support for 

an unplanned loss of well control event. In the event of any well control event, Wild 

Well Control would be contacted and mobilized if required to support Anadarko’s 

operational team both in the onshore and offshore locations. 

 The conceptual relief well design is similar to the design of the Lloyd Ridge Block 

621 #1 (Location “A”) in that casing weights, grades and setting points would be very 

similar or identical. The conceptual well design is not anticipated to take over two 

days to finalize upon initialization. 
 

 A shallow hazard assessment has been completed for applicable portions of Lloyd 

Ridge Block 621. Site Clearance letters for two surface locations in Lloyd Ridge 

Block 621 have been completed and approved. Furthermore, the potential for high 

density chemo-synthetic communities in the study area are negligible. Depending on 

the nature of the blowout scenario, well geometry and total depth required to intersect 

the blowout, the most suitable surface location will be chosen and submitted for 

approval as the location for the relief well. 

 Anadarko’s philosophy is to carry adequate inventory in stock to drill a complete 

well(s) from surface to TD. Back-up long lead equipment equivalent to the original 

well design will be carried in stock to allow a rapid response. This includes a spare 

deepwater sub-sea wellhead system and the large OD casing (36", 22", 13-5/8" and 9-

7/8") and connectors required for the first part of the well. Smaller OD casing is 

considered widely available on the ground in the GOM and would be resourced out of 

existing inventory or from suppliers as required. 

 Existing service agreements will be in place for support services including drilling 

fluids, casing running, cementing, ROV’s, solids control, mud logging, directional 

drilling, LWD/MWD, logging, boats and helicopters. 

 Specialist services for range finding to drill the relief well in close proximity to the 

original wellbore at the reservoir depth will be provided through Vector Magnetics 

LLC. Sperry Drilling and Anadrill have in-house personnel to supplement Vector 

Magnetics under our existing directional drilling agreements. 
 

C 

GEOLOGICAL AND GEOPHYSICAL INFORMATION 

(a) Geological Description 

Discussions regarding geologic information are considered proprietary and have been omitted 

from this public copy of the EP. 

(b) Structure Contour Maps 

Current structure maps drawn to the top of each productive hydrocarbon sand showing the entire 

lease block, the surface locations of each well and locations of geological cross-sections, are 

enclosed as Attachment C-1.

(c) Interpreted 2-D and/or 3-D Seismic Lines 

Interpreted seismic lines are enclosed as Attachment C-2.

(d) Geological Structure Cross-Sections 

Interpreted geological structure cross-sections showing the location and depth of each proposed 

well are enclosed as Attachment C-3.

(e) Shallow Hazards Report 

A Shallow Hazards Report prepared by Geoscience Earth & Marine Services, Inc. (GEMS) for 

Lloyd Ridge Block 621 is being submitted with this plan (Report No. 0709-1668). The report 

covers portions of the following Lloyd Ridge Blocks: 576, 577, 620, 621, 664 and 665. An 

Addendum to Site Clearance Letters for Proposed Wellsites A and B, Lloyd Ridge Block 621 is 

also being submitted with the Shallow Hazards Report. 

(f) Shallow Hazards Assessment 

Shallow hazards site clearance letters for the proposed well locations are included in the 

Addendum to Site Clearance Letters for Proposed Wellsites A and B, Lloyd Ridge Block 621 

and enclosed as Attachment C-4.
 

(g) High-resolution Seismic Lines 

High resolution seismic lines are enclosed as Attachment C-5.

(h) Stratigraphic Column 

A generalized stratigraphic column depicting the wells from the seafloor to total depth is 

included as Attachment C-6. 

(i) Time Vs. Depth Tables 

The proposed activities under this EP are not considered to be in areas where there is no well 

control. Therefore, a seismic travel time versus depth table is not required per NTL No. 2008-

G04. 
10615 SHADOW WOOD DRIVE 

SUITE 200 

HOUSTON, TEXAS 77043 

Phone: (713) 468-1410 

Fax: (713) 468-1438 

E-mail: gems@gemsinc.com

January 19, 2011 Project No. 0111-1870 

Anadarko Petroleum Corporation 

1201 Lake Robbins Drive 

The Woodlands, Texas 77380 

Attention: Mr. Paul Chandler 

ADDENDUM TO REPORT No. 0709-1668 

SITE CLEARANCE LETTER FOR 

PROPOSED EXPLORATION WELLSITE A 

BLOCK 621, LLOYD RIDGE AREA, 

GULF OF MEXICO 

Geoscience Earth & Marine Services Inc.®, (GEMS) was contracted by Anadarko Petroleum Corporation, 

(Anadarko) to provide an assessment of the shallow conditions at the proposed drilling location A in 

Block 621 (OCS G-33323), Lloyd Ridge Area (LL), Gulf of Mexico. This letter addresses specific seafloor 

and subsurface conditions around the proposed location to the limit of investigation, a depth of about 5,220 ft 

below the mudline (bml). 

This letter is based on the findings provided within the geohazard report “Geologic and Stratigraphic 

Assessment for Portions of Blocks 576, 577, 620, 621, 664, and 665, Lloyd Ridge Area, Gulf of Mexico” 

(GEMS Project No. 0709-1668). The text, maps, and figures included in the report provide detail on the 

regional geology of the Study Area. This letter is intended to supplement that report with details pertaining 

directly to the proposed wellsite. 

The Proposed Wellsite A location was previously assessed within the GEMS Project No. 0709-1668 

geohazard report, submitted to Anadarko Petroleum Corporation on September 25, 2009. The above 

geohazard assessment was in compliance with the Bureau of Ocean Energy Management, Regulation, and 

Enforcement (BOEMRE) Notice-to-Lessees (NTL’s) 2000-G20, 2005-G07, 2008-G05, and 2008-G20 

(MMS 2000, 2005, 2008a, and 2008b). 

Effective January 27, 2010, NTL 2009-G40 outlines revised requirements established to protect deepwater 

benthic communities from damage caused by OCS oil and gas operations (MMS, 2010). This addendum 

letter satisfies the updated requirements, as provided in NTL 2009-G40. 

Proposed Well Location 

The surface location for the Proposed Exploration Wellsite A is in the southwestern portion of Block 621, 

Lloyd Ridge Area, Gulf of Mexico. The coordinates for the proposed location are as follows: 

Proposed Wellsite A 

Spheroid & Datum: Clark 1866, NAD27 

Projection: UTM Zone 16 North, US Feet Line Reference Block Calls LL 621 

X: 1,412,971 Latitude: 27o 19' 41.55723" N Inline: 6988 3,212 ft FWL 

Y: 9,917,350 Longitude: 87o 42' 02.74417" W Crossline: 10011 1,512 ft FSL 
Project No. 0709-1668 

- 2 - 

Our assessment addresses the seafloor conditions within a 2,000-ft radius around the proposed wellsite location; 

therefore, anchor touch-down locations have not been considered in this assessment. Anadarko plans to drill this 

well using a dynamically positioned drilling vessel. 

Attachments 

The page-size maps and figures accompanying this letter illustrate the seafloor and shallow geologic 

conditions at the Proposed Exploration Wellsite A: 

Map A-1: Bathymetry Map 

Map A-2: Seafloor Rendering 

Map A-3: Seafloor Amplitude Rendering 

Map A-4: Geologic Features Map 

Figure A-1: Portions of Inline 6988 and Crossline 10011 Showing Conditions Beneath Proposed 

Wellsite A 

Figure A-2: Tophole Prognosis Chart, Proposed Wellsite A, Lloyd Ridge Block 621 

NTL Requirements 

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

(BOEMRE) Notice to Lessees 2008-G05 and 2009-G40 (MMS, 2008a and 2010). The Federal lease block 

LL 621 and immediate surrounding blocks are not considered archaeologically significant (MMS, 2008b); 

therefore, requirements set forth in NTL 2005-G07 are not applicable (MMS, 2005). 

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

hazard assessments with approval from the Bureau of Ocean Energy Management, Regulation, and Enforcement, 

Gulf of Mexico Region. A power spectrum analysis was conducted from the 3-D seismic data cube provided by 

Anadarko to illustrate the data parameters. The power spectrum curve (below) was generated within a 500-ft 

radius of the intersection of the inlines and crosslines at the proposed wellsite over a time interval from the 

seafloor to one second below mudline. 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, LL 621, Proposed Wellsite A
Project No. 0709-1668 

- 3 - 

Wellsite Conditions 

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

wellsite. 

Water Depth, Seabed Sediments, and Slope. Seafloor conditions are favorable at the proposed wellsite 

location. The water depth at the proposed surface location is approximately -9,089 ft (Map A-1). The

seafloor is slightly irregular or hummocky at the proposed site (Map A-2). The irregular seafloor is the 

surface expression of buried mass-transport deposits. A surficial drape of high water-content silty clays 

likely covers the seafloor. The seafloor slopes to the southeast at about 0.7°.

Deepwater Benthic Communities. Features or areas that could support high-density deepwater benthic 

communities are not located within 2,000 ft of the proposed location. The Seafloor Amplitude Rendering 

(Map A-3) shows normal or ambient amplitudes along the seabed at, and near, the proposed wellsite.

Man-Made Features. There are no existing wells, pipelines, or platforms within LL 621. The closest 

existing infrastructure to the Proposed Wellsite A are three exploration wells, a gas pipeline, and an

umbilical approximately 16 miles to the north-northwest in LL 399 (BOEMRE, 2011). 

Stratigraphy. Stratigraphic conditions are shown on Figures A-1 and A-2. The Seafloor to Horizon 10 

sequence, referred to as Unit 1 (seafloor to approximately 415 ft bml), is defined by a low-amplitude to 

amorphous geophysical character. This unit is likely clay-dominated mass-transport deposits. Horizon 10 to 

Horizon 20, Unit 2 (415 ft to 876 ft bml), is characterized by stratified, low-amplitude reflectors. This 

sequence is likely hemipelagic mud-dominated turbidite deposits. 

Horizon 20 to Horizon 30, Unit 3, (876 ft to 1,640 ft bml) is defined by low to high-amplitude reflectors. 

This unit consists largely of sand-rich levee and overbank deposits. Horizon 30 to the Limit of Investigation, 

Units 4 and 5 (1,640 ft to 5,222 ft bml), are characterized by low- to high-amplitude reflectors. These units 

show several mass-transport deposits interlayered with condensed clays. 

Faults. The proposed wellbore will not intersect any surface or buried faults.

Shallow Gas. There are no apparent surface and subsurface high-amplitude anomalies directly beneath the 

proposed wellsite (Maps A-3 and A-4). There is relatively no probability of encountering gas beneath the 

wellsite. The closest subsurface high-amplitude event to a vertical hole occurs approximately 435 ft 

northwest of this location in Unit 5 (3,316 ft to 5,222 ft bml). This event occurs within discontinuous 

mass-transport sediments and may indicate lithologic variations or a minor accumulation of shallow gas. 

This anomalous interval is not continuous to the wellsite and should not impact drilling at this location. 

Water Flow. There is a moderate potential for shallow water flow within Unit 3 (876 ft to 1,640 ft bml), 

Figure A-2. Thin sands may be encountered within some levee and overbank deposits within the unit. A low 

potential for shallow water flow occurs in Units 4 and 5. The shallow water flow potential is considered 

negligible through the remaining generally clay-rich sections. 

Closing 

The Proposed Wellsite A, Lloyd Ridge Block 621, appears suitable for exploration drilling operations. 

Sediments within the interval from about 876 ft to 1,640 ft bml may contain continuous thin sands. Caution 

is advised as these sands may be fluid-filled within this interval. 
Project No. 0709-1668 

- 4 - 

 Sincerely, 

GEOSCIENCE EARTH & 

MARINE SERVICES, INC. ®

 

 

Carla R. Cleveland Daniel L. Lanier 

Associate Geoscientist Vice President/Geoscience 

Erin Williams Janes 

Project Manager/Senior Geoscientist 

References: 

Bureau of Ocean Energy Management, Regulation, and Enforcement, 2011, ASCII Data Files, published on the 

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

accessed January, 2011. 

Coffeen, J.A., 1978, Seismic Exploration Fundamentals: PPC Books, a division of Petroleum Publishing Co., Tulsa, Ok. 

277 p. 

Minerals Management Service, 2000, Notice to lessees and operators of federal oil and gas leases in the outer 

continental shelf, Gulf of Mexico OCS region, deepwater chemosynthetic communities: U. S. Department of the 

Interior, Minerals Management Service, Gulf of Mexico, NTL 2000-G20. 

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 operators of federal oil, gas, and sulphur leases and pipeline 

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

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

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

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

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

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

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

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

Minerals Management Service, Gulf of Mexico, NTL 2009-G40. 

 

3.500

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4.800

4.900

5.000

5.100

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3.600

3.700

3.800

3.900

4.000

4.100

4.200

4.300

4.400

4.500

4.600

4.700

4.800

4.900

5.000

5.100

5.200

6900.0

10011.0

6975.0

10011.0

7050.0

10011.0

20000 25000 30000

6988.0

9900.0

6988.0

9975.0

6988.0

10050.0

6988.0

10125.0

Line:

Trace:

15000 20000 25000

3.500

3.600

3.700

3.800

3.900

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4.100

4.200

4.300

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4.600

4.700

4.800

4.900

5.000

5.100

5.200

Horizontal

Distance (ft):

TWO-WAY TRAVEL TIME (SEC)TWO-WAY TRAVEL TIME (SEC)

PROPOSED 

WELLSITE A

PROPOSED 

WELLSITE A

WEST EAST NORTH SOUTH

Project No. 0111-1870 Filename: 11870_fig_A-1.cdr

INLINE 6988

Figure A-1. Portions of Inline 6988 and Crossline 10011 Showing

 Conditions Beneath Proposed Wellsite A

CROSSLINE 10011

Horizon 10

Seafloor

Horizon 30

Horizon 20

Horizon 40

RELATIVE AMPLITUDE 

TROUGH PEAK

LL

620

LL

621

LL

665

LL

621

RELATIVE AMPLITUDE 

TROUGH PEAK

UNIT 1

UNIT 2

UNIT 3

UNIT 4

UNIT 5

UNIT 1

UNIT 2

UNIT 3

UNIT 4

UNIT 5
6988.0

9975.0

6988.0

10050.0

Line:

Trace:

15000 20000

3.500

3.600

3.700

3.800

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4.100

4.200

4.300

4.400

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4.600

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4.800

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5.100

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Horizontal

Distance (ft):

PROPOSED

WELLSITE A

WATER

FLOW AND

GAS

POTENTIAL

Shallow Water Flow and Gas Potential

HIGH

0 1 2 3

0 = NEGLIGIBLE

1 = LOW

2 = MODERATE

3 = HIGH

NEGLIGIBLE

Horizon

Figure A-2. Tophole Prognosis Chart, Proposed Wellsite A, Lloyd Ridge Block 621

Project No. 0111-1870 Filename: 11870_fig_A-2.cdr

Water 

Flow

Gas

3-D Seismic Section Through

Proposed Wellsite A

X = 1,412,971 FT; Y = 9,917,350 FT

 Inline 6988 at Crossline 10011

INLINE 6988 TWO-WAY TIME TRAVEL (SEC)

SEAFLOOR

HORIZON 10

-9,089

-9,504

-9,965

415

876

3.694

3.857

4.022

4.272 -10,729 1,640

W E

Lithology/Stratigraphy Potential Drilling

Constraints

Horizon

TWT

(sec, bss)

Depth

(ft, bml)

Depth

(ft, bss)

Horizon

TWT

(sec, bml)

0.163

0.328

0.578

HORIZON 20

HORIZON 30

HORIZON 40

Interface

4.611

4.757

-11,406

-11,877

-12,405

0.782

0.917

1.063

4.476 2,317

2,788

3,316

Seafloor slopes about 0.7° to the southeast.

There is a negligible potential for high-density

deepwater benthic communities within 2,000 ft of the

proposed location.

LIMIT OF

INVESTIGATION 5.250 1.556 -14,311 5,222

Interface

Clay-rich mass-transport deposits.

Mud-dominated turbidites.

Sand-rich levee and overbank deposits.

Stacked mass-transport deposits interlayered with

thin sand seams and condensed clays.

Stacked mass-transport deposits interlayered with 

thin sand seams and condensed clays.

Negligible potential for encountering shallow water flow

and shallow gas.

Negligible potential for encountering shallow water flow

and shallow gas.

Moderate potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

RELATIVE AMPLITUDE 

TROUGH PEAK

LL

620

LL

621

UNIT 1 UNIT 2 UNIT 3 UNIT 4 UNIT 5

Clay-rich mass-transport deposits interlayered with

thin sand seams.

Low potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

Low potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

Low potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

Low potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

Clay-rich mass-transport deposits interlayered with 

thin sand seams.
10615 SHADOW WOOD DRIVE 

SUITE 200 

HOUSTON, TEXAS 77043 

Phone: (713) 468-1410 

Fax: (713) 468-1438 

E-mail: gems@gemsinc.com

January 19, 2011 Project No. 0111-1870 

Anadarko Petroleum Corporation 

1201 Lake Robbins Drive 

The Woodlands, Texas 77380 

Attention: Mr. Paul Chandler 

ADDENDUM TO REPORT No. 0709-1668 

SITE CLEARANCE LETTER FOR 

PROPOSED EXPLORATION WELLSITE B 

BLOCK 621, LLOYD RIDGE AREA, 

GULF OF MEXICO 

Geoscience Earth & Marine Services Inc.®, (GEMS) was contracted by Anadarko Petroleum Corporation, 

(Anadarko) to provide an assessment of the shallow conditions at the proposed drilling location B in Block 

621 (OCS G-33323), Lloyd Ridge Area (LL), Gulf of Mexico. This letter addresses specific seafloor and 

subsurface conditions around the proposed location to the limit of investigation, a depth of about 5,220 ft 

below the mudline (bml). 

This letter is based on the findings provided within the geohazard report “Geologic and Stratigraphic 

Assessment for Portions of Blocks 576, 577, 620, 621, 664, and 665, Lloyd Ridge Area, Gulf of Mexico” 

(GEMS Project No. 0709-1668). The text, maps, and figures included in the report provide detail on the 

regional geology of the Study Area. This letter is intended to supplement that report with details pertaining 

directly to the proposed wellsite. 

The Proposed Wellsite B location was previously assessed within the GEMS Project No. 0709-1668 

geohazard report, submitted to Anadarko Petroleum Corporation on September 25, 2009. The above 

geohazard assessment was in compliance with the Bureau of Ocean Energy Management, Regulation, and 

Enforcement (BOEMRE) Notice-to-Lessees (NTL’s) 2000-G20, 2005-G07, 2008-G05, and 2008-G20 

(MMS 2000, 2005, 2008a, and 2008b). 

Effective January 27, 2010, NTL 2009-G40 outlines revised requirements established to protect deepwater 

benthic communities from damage caused by OCS oil and gas operations (MMS, 2010). This addendum 

letter satisfies the updated requirements, as provided in NTL 2009-G40. 

Proposed Well Location 

The surface location for the Proposed Exploration Wellsite B is in the southwestern portion of Block 621, 

Lloyd Ridge Area, Gulf of Mexico. The coordinates for the proposed location are as follows: 

Proposed Wellsite B 

Spheroid & Datum: Clark 1866, NAD27 

Projection: UTM Zone 16 North, US Feet Line Reference Block Calls LL 621 

X: 1,412,075 Latitude: 27o 20' 02.32992" N Inline: 6956 2,315 ft FWL 

Y: 9,919,452 Longitude: 87o 42' 12.81311 " W Crossline: 9990 3,612 ft FSL 
Project No. 0709-1668 

- 2 - 

Our assessment addresses the seafloor conditions within a 2,000-ft radius around the proposed wellsite location; 

therefore, anchor touch-down locations have not been considered in this assessment. Anadarko plans to drill this 

well using a dynamically positioned drilling vessel. 

Attachments 

The page-size maps and figures accompanying this letter illustrate the seafloor and shallow geologic 

conditions at the Proposed Exploration Wellsite B: 

Map B-1: Bathymetry Map 

Map B-2: Seafloor Rendering 

Map B-3: Seafloor Amplitude Rendering 

Map B-4: Geologic Features Map 

Figure B-1: Portions of Inline 6956 and Crossline 9990 Showing Conditions Beneath Proposed 

Wellsite B 

Figure B-2: Tophole Prognosis Chart, Proposed Wellsite B, Lloyd Ridge Block 621 

NTL Requirements 

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

(BOEMRE) Notice to Lessees (NTL’s) 2008-G05 and 2009-G40 (MMS, 2008a and 2010). The Federal lease 

block LL 621 and immediate surrounding blocks are not considered archaeologically significant (MMS, 2008b); 

therefore, requirements set forth in NTL 2005-G07 are not applicable (MMS, 2005). 

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

hazard assessments with approval from the Bureau of Ocean Energy Management, Regulation, and Enforcement, 

Gulf of Mexico Region. A power spectrum analysis was conducted from the 3-D seismic data cube provided by 

Anadarko to illustrate the data parameters. The power spectrum curve (below) was generated within a 500-ft 

radius of the intersection of the inlines and crosslines at the proposed wellsite over a time interval from the 

seafloor to one second below the mudline. 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, LL 621, Proposed Wellsite B
Project No. 0709-1668 

- 3 - 

Wellsite Conditions 

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

wellsite. 

Water Depth, Seabed Sediments, and Slope. Seafloor conditions are favorable at the proposed wellsite 

location. The water depth at the proposed surface location is approximately -9,087 ft (Map B-1). The

seafloor is slightly irregular or hummocky at the proposed site (Map B-2). The irregular seafloor is the 

surface expression of buried turbidite and mass-transport deposits. A surficial drape of high water-content 

silty clays likely covers the seafloor. The seafloor slopes to the southeast at about 0.6°.

Deepwater Benthic Communities. Features or areas that could support high-density deepwater benthic 

communities are not located within 2,000 ft of the proposed location. The Seafloor Amplitude Rendering 

(Map B-3) shows normal or ambient amplitudes along the seabed at, and near, the proposed wellsite.

Man-Made Features. There are no existing wells, pipelines, or platforms within LL 621. The closest 

existing infrastructure to the Proposed Wellsite A is three exploration wells, a gas pipeline, and an umbilical 

approximately 16 miles to the north-northwest in LL 399 (BOEMRE, 2011). 

Stratigraphy. Stratigraphic conditions are shown on Figures B-1 and B-2. The Seafloor to Horizon 10 

(396 ft bml) sequence (Unit 1) is defined by a low-amplitude to amorphous character. This unit is likely a 

clay-dominated mass-transport interval. Horizon 10 to Horizon 20, Unit 2 (396 ft to 862 ft bml), generally 

comprises stratified, low-amplitude reflectors. This sequence is likely hemipelagic, mud-dominated turbidite 

deposits. 

Horizon 20 to Horizon 30, Unit 3, (862 ft to 1,632 ft bml) is defined by low to high-amplitude reflectors. 

This unit consists largely of sand-rich levee and overbank deposits. Horizon 30 to the Limit of Investigation, 

Units 4 and 5 (1,632 ft to 5,222 ft bml), is characterized by low- to high-amplitude reflectors. These units 

show several mass-transport deposits stacked between condensed clays. 

Faults. The proposed wellbore will not intersect any surface or buried faults.

Shallow Gas. There are no apparent surface and subsurface high-amplitude anomalies directly beneath the 

proposed wellsite (Maps B-3 and B-4). There is relatively no probability of encountering gas beneath the 

proposed well. The closest subsurface high-amplitude event to a vertical hole occurs approximately 675 ft 

south-southwest of this location in Unit 5 (3,305 ft to 5,222 ft bml). This event occurs within discontinuous 

mass-transport sediments and may indicate lithologic variations or minor accumulations of shallow gas. This 

anomalous interval is not continuous to the wellsite and should not impact drilling at this location. 

Water Flow. There is a moderate potential for shallow water flow within Unit 3 (862 ft to 1,632 ft bml), 

Figure B-2. Thin sands may be encountered within some levee and overbank deposits. A low potential for 

shallow water flow occurs in Units 4 and 5. The shallow water flow potential is considered negligible

through the remaining generally clay-rich sections.

Closing 

The Proposed Wellsite B, Lloyd Ridge Block 621, appears suitable for exploration drilling operations. 

Sediments within the interval from about 862 ft to 1,632 ft bml may contain continuous thin sands. Caution 

is advised as these sands may be fluid-filled within this interval. 
Project No. 0709-1668 

- 4 - 

 Sincerely, 

GEOSCIENCE EARTH & 

MARINE SERVICES, INC. ®

 

 

Carla R. Cleveland Daniel L. Lanier 

Associate Geoscientist Vice President/Geoscience 

Erin Williams Janes 

Project Manager/Senior Geoscientist 

References: 

Bureau of Ocean Energy Management, Regulation, and Enforcement, 2011, ASCII Data Files, published on the 

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

accessed January, 2011. 

Coffeen, J.A., 1978, Seismic Exploration Fundamentals: PPC Books, a division of Petroleum Publishing Co., Tulsa, Ok. 

277 p. 

Minerals Management Service, 2000, Notice to lessees and operators of federal oil and gas leases in the outer 

continental shelf, Gulf of Mexico OCS region, deepwater chemosynthetic communities: U. S. Department of the 

Interior, Minerals Management Service, Gulf of Mexico, NTL 2000-G20. 

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 operators of federal oil, gas, and sulphur leases and pipeline 

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

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

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

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

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

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

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

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

Minerals Management Service, Gulf of Mexico, NTL 2009-G40. 

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6975.0

9990.0

7050.0

9990.0

20000 25000 30000

6956.0

9900.0

6956.0

9975.0

6956.0

10050.0

6956.0

10125.0

Line:

Trace:

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4.100

4.200

4.300

4.400

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4.600

4.700

4.800

4.900

5.000

5.100

5.200

Horizontal

Distance (ft):

TWO-WAY TRAVEL TIME (SEC)TWO-WAY TRAVEL TIME (SEC)

PROPOSED 

WELLSITE B

PROPOSED 

WELLSITE B

WEST EAST NORTH SOUTH

Project No. 0111-1870 Filename: 11870_fig_B-1.cdr

INLINE 6956

Figure B-1. Portions of Inline 6956 and Crossline 9990 Showing

 Conditions Beneath Proposed Wellsite B

CROSSLINE 9990

Horizon 10

Seafloor

Horizon 30

Horizon 20

Horizon 40

RELATIVE AMPLITUDE 

TROUGH PEAK

LL

620

LL

621

LL

665

LL

621

RELATIVE AMPLITUDE 

TROUGH PEAK

UNIT 1

UNIT 2

UNIT 3

UNIT 4

UNIT 5

UNIT 1

UNIT 2

UNIT 3

UNIT 4

UNIT 5
6956.0

9900.0

6956.0

9975.0

6956.0

10050.0

Line:

Trace:

15000 20000

3.500

3.600

3.700

3.800

3.900

4.000

4.100

4.200

4.300

4.400

4.500

4.600

4.700

4.800

4.900

5.000

5.100

5.200

Horizontal

Distance (ft):

PROPOSED

WELLSITE B

WATER

FLOW AND

GAS

POTENTIAL

Shallow Water Flow and Gas Potential

HIGH

0 1 2 3

0 = NEGLIGIBLE

1 = LOW

2 = MODERATE

3 = HIGH

NEGLIGIBLE

Horizon

Figure B-2. Tophole Prognosis Chart, Proposed Wellsite B, Lloyd Ridge Block 621

Project No. 0111-1870 Filename: 11870_fig_B-2.cdr

Water 

Flow

Gas

3-D Seismic Section Through

Proposed Wellsite B

X = 1,412,075 FT; Y = 9,919,452 FT

 Inline 6956 at Crossline 9990

INLINE 6956 TWO-WAY TIME TRAVEL (SEC)

SEAFLOOR

HORIZON 10

-9,087

-9,483

-9,949

396

862

3.693

3.849

4.016

4.268 -10,719 1,632

W E

Lithology/Stratigraphy Potential Drilling

Constraints

Horizon

TWT

(sec, bss)

Depth

(ft, bml)

Depth

(ft, bss)

Horizon

TWT

(sec, bml)

0.156

0.323

0.575

HORIZON 20

HORIZON 30

HORIZON 40

Interface

4.604

4.753

-11,309

-11,854

-12,392

0.754

0.911

1.060

4.447 2,222

2,767

3,305

Seafloor slopes about 0.6° to the southeast.

There is a negligible potential for high-density

deepwater benthic communities within 2,000 ft of the

proposed location.

LIMIT OF

INVESTIGATION 5.250 1.556 -14,311 5,222

Interface

Negligible potential for encountering shallow water flow

and shallow gas.

Negligible potential for encountering shallow water flow

and shallow gas.

RELATIVE AMPLITUDE 

TROUGH PEAK

LL

620

LL

621

Clay-rich mass-transport deposits.

Mud-dominated turbidites.

Sand-rich levee and overbank deposits.

Stacked mass-transport deposits interlayered with

thin sand seams and condensed clays.

Stacked mass-transport deposits interlayered with

thin sand seams and condensed clays.

UNIT 1 UNIT 2 UNIT 3 UNIT 4 UNIT 5

Clay-rich mass-transport deposits interlayered with 

thin sand seams.

Clay-rich mass-transport deposits interlayered with 

thin sand seams.

Low potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

Low potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

Low potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

Low potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.

Moderate potential for encountering shallow water flow.

Negligible potential for encountering shallow gas.
 

D 

HYDROGEN SULFIDE INFORMATION 

Discussions regarding geologic information are considered proprietary and have been omitted 

from this public copy of the EP. Anadarko requests that the Lloyd Ridge Block 621 area be 

classified as “an area where the absence of H2S has been confirmed”. 
 

E 

BIOLOGICAL, PHYSICAL, AND SOCIOECONOMIC INFORMATION 

(a) Chemosynthetic Communities Report 

The seafloor disturbing activities proposed in this plan are in approximately 9,087-9,089' of 

water. The well will be drilled with a DP drillship or a DP semi-submersible drilling rig. 

Maps 

A map prepared using 3-D seismic data to depict bathymetry, seafloor and shallow geological 

features, and surface locations of the proposed wells is included in Section A. 

Analysis 

Features or areas that could support high-density chemosynthetic communities are not located 

within 2,000' of each proposed muds and cuttings discharge location. 

Features or areas that could support high-density chemosynthetic communities are not located 

within 250' of any seafloor disturbances. There will be no use of anchors. 

(b) Topographic Features Map 

The proposed activities are not within 1,000' of a no-activity zone or within the 3-mile radius 

zone of an identified topographic feature. Therefore, no map is required per NTL No. 2008-G04. 

(c) Topographic Features Statement (Shunting) 

Anadarko does not plan to drill more than two wells from the same surface location within the 

Protective Zone of an identified topographic feature. Therefore, the topographic features 

statement required by NTL No. 2008-G04 is not applicable. 

(d) Live Bottoms (Pinnacle Trend) Map 

The activities proposed in this plan are not within 200' of any pinnacle trend feature with vertical 

relief equal to or greater than 8'. Therefore, no map is required per NTL No. 2008-G04. 

(e) Live Bottoms (Low Relief) Map 

The activities proposed in this plan are not within 100' of any live bottom low relief features. 

Therefore, no map is required per NTL No. 2008-G04. 

(f) Potentially Sensitive Biological Features 

The activities proposed in this plan are not within 200' of any potentially sensitive biological 

features. Therefore, no map is required per NTL No. 2008-G04. 
 

(g) Remotely Operated Vehicle (ROV) Monitoring Survey Plan 

Lloyd Ridge Block 621 is located within Deepwater Grid Area 21. This grid is considered to 

have “inadequate ROV survey coverage”, and, therefore, under the guidance set out in NTL No. 

2008-G06, a Remotely Operated Vehicle Monitoring Survey Plan is required. 

Pursuant to NTL 2008-G06, operators may be required to conduct remotely operated vehicle 

(ROV) surveys during the proposed operations for the purpose of biological and physical 

observations. 

Anadarko is familiar with the ROV survey and reporting provisions of NTL 2008-G06; and if 

required, will conduct a survey. 

Anadarko will utilize ROV equipped with video imaging capabilities. The survey pattern will 

consist of six transects centered on the well location with tracks extending approximately 100 

meters away from the well on bearings of 30 degrees, 90 degrees, 150 degrees, 210 degrees, 270 

degrees and 330 degrees. The seafloor will be videotaped continuously along each track. 

Anadarko will make biological and physical observations as described in the subject NTL and 

Form MMS-141 prior to commencing operations and prior to moving off location. The 

observations will be documented using Form MMS-141, or a facsimile and submitted along with 

videotapes, and any other imagery obtained, to the BOEM/BSEE within 60 days after 

completion of the final ROV survey. 

(h) Threatened and Endangered Species Information 

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

actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of a 

listed species, or destroy or adversely modify its designated critical habitat. 

In accordance with the 30 CFR 550, Subpart B, effective May 14, 2007, and further outlined in 

Notice to Lessees (NTL) 2008-G04, lessees/operators are required to address site-specific 

information on the presence of federally listed threatened or endangered species and critical 

habitat designated under the ESA and marine mammals protected under the Marine Mammal 

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

Currently there are no designated critical habitats for the listed species in the Gulf of Mexico 

Outer Continental Shelf; however, it is possible that one or more of these species could be seen 

in the area of our operations. The following table reflects the Federally-listed endangered and 

threatened species in the lease area and along the northern Gulf coast: 
 

Species Scientific Name Status 

Potential Presence Critical Habitat 

Designated in 

Gulf of Mexico 

Lease 

Area Coastal 

Marine Mammals 

Sperm whale Physeter macrocephalus E X -- None

Florida manatee Trichechus manatus 

latirostris E -- X Florida 

(Peninsular)

Blue whale Balaenoptera musculus E Xa -- None

Fin whale Balaenoptera physalus E Xa -- None

Humpback whale Megaptera novaeangliae E Xa -- None

North Atlantic right whale Eubalaena glacialis E Xa -- None

Sei whale Balaenoptera borealis E Xa -- None

Sea Turtles 

Loggerhead turtle Caretta caretta T X X None

Green turtle Chelonia mydas T, Eb X X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempii E X X None

Birds 

Piping Plover Charadrius melodus T -- X 

Coastal Texas, 

Louisiana, Mississippi, 

Alabama, and Florida 

(Panhandle) 

Whooping Crane Grus americana E -- X 

Coastal Texas 

(Aransas National 

Wildlife Refuge)

Fishes 

Gulf sturgeon Acipenser oxyrinchus desotoi T -- X 

Coastal Louisiana, 

Mississippi, Alabama, 

and Florida (Panhandle)

Terrestrial Mammals 

Beach mice (Alabama, 

Choctawhatchee, Perdido 

Key, St. Andrew)

Peromyscus polionotus E -- X Alabama and Florida 

(Panhandle) beaches 

Abbreviations:  E = Endangered; T = Threatened.   a

   The blue, fin, humpback, North Atlantic right, and sei whales are rare or extralimital in the Gulf of Mexico and are

unlikely to be present in the lease area. b

   The green sea turtle is threatened, except for the Florida breeding population, which is listed as endangered.

The Environmental Impact Analysis in Section N of this plan further discusses potential impacts 

and mitigation measures related to threatened and endangered species. 

(i) Archaeological Report 

Lloyd Ridge Block 621 is not in an area designated as an area of high archaeological potential 

and, as such, an Archaeological Report is not required per NTL No. 2008-G04. However an 

“Archaeological Assessment Report” prepared by C & C Technologies Survey Services (Project 

#110566) has been included with this EP submittal for future reference. 

(j) Air and Water Quality Information

Lloyd Ridge Block 621 is located 143 miles from the nearest shoreline. Drilling/completion 

operations will produce air pollutant emissions, but as provided in the Air Emissions Spreadsheet 

(see Section G of this plan), these operations are below the exemption levels. 
 

These drilling/completion operations will result in the discharge of authorized effluents under the 

EPA Region IV General permit. Impacts of these discharges are expected to be minimal on 

water quality in the area. 

(k) Socioeconomic Information 

1) Anadarko will utilize its existing shorebase located in Fourchon, Louisiana which is fully 

staffed and operational, and does not expect to employ persons from within the State of Florida. 

2) Anadarko does not expect to purchase major supplies, services, energy, water or other 

resources from within the State of Florida for these operations. 

3) Anadarko does not expect to hire contractors or vendors from within the State of Florida. 
 

F 

WASTE AND DISCHARGE INFORMATION 

The following estimates were prepared utilizing Anadarko’s experience with similar drilling operations. 

Estimated maximum discharge rates are reflected below. 

(a) Projected Generated Wastes 

Type of Waste Composition Projected Amount Treatment/Storage/Disposal 

Synthetic-based drilling 

fluids 

Synthetic-based 

drilling muds 

13,000 bbls per well Re-use and/or transport to shore in 

tanks and/or cutting boxes to 

Fourchon, Louisiana and on to 

Newpark Base. If recycled, returned to 

vendor (Baroid or MI.) 

Cuttings wetted with 

synthetic-based muds 

 Cuttings coated with 

synthetic drilling 

muds/fluids, 

including drilled out 

cement. 

2,300 bbls/well Treated and discharged overboard. 

*Note, an estimated 5-10% of cuttings 

may be transported to shore in tanks 

and/or cutting boxes and on to the 

base/transfer station if oil still 

remains. 

Water-based drilling 

fluids 

Water-based drilling 

muds (NaCl 

saturated, seawater, 

freshwater, barite) 

63,000 bbls/well Discharge overboard or at seafloor 

Cuttings wetted with 

water-based fluids 

Cuttings coated with 

water-based drilling 

muds/fluids 

23,166 bbls/well Discharge at seafloor 

Chemical product waste 

(well treatment fluids) 

Ethylene glycol 

Methanol 

100 bbls/month 

25 bbls/month 

Transport to shore in barrels to 

Fourchon, Louisiana for pick up. 

Completion Fluids Brine, spent acid, 

prop sand, debris 

3,000 bbls/ well Transport to shore in barrels to 

Fourchon, Louisiana and on to 

Newpark Base. 

Non-pollutant 

completion fluids 

Low density 

uninhibited 

completion brines 

5,000 bbls/well Discharge overboard 

Workover fluids Brine, spent acid, 

prop sand, debris 

3,000 bbls/well Transport to shore in barrels to 

Fourchon, Louisiana and on to 

Newpark Base. 

Trash Refuse generated 

during operations 

50 bbls/month Transport to shore in disposal bags by 

vessel to shorebase for pickup by 

municipal operations. 

*Sanitary Wastes Treated human body 

waste 

300,000 gals/well Chlorinate and discharge overboard 

*Domestic Waste Gray water 300,000 gals/well Chlorinate and discharge overboard 

Deck drainage Platform washings 

and rainwater 

210,000 bbls/well Treat for oil and grease and discharge 

overboard 

Produced water N/A N/A N/A 

Desalinization Unit Seawater 21,000 bbls/well Discharge overboard 

Wash water Drill water (fresh) 3,000 bbls/60 days 

well 

Discharge overboard 

Blowout preventer fluid Blend (3% Stack 

Magic & Filtered 

Fresh Water) 

925 gals/week/well Discharge at seafloor 

Ballast water Seawater As needed Discharge overboard 
 

Cont. 

Type of Waste Composition Projected Amount Treatment/Storage/Disposal 

Bilge water Seawater 685 bbls/well Discharge overboard through 15 ppm 

equipment 

Excess cement at the 

seafloor 

Nitrified cement 

slurry 

501 bbls/well Discharge at seafloor 

Fire water Seawater 137,142 bbls/day Discharge overboard 

Cooling water Seawater 137,142 bbls/day Discharge overboard 

Produced Sand N/A N/A N/A 

Used oil Excess oil from 

engines 

806.25 bbls Transport in totes to shore for 

recycling 

(b) Projected Ocean Discharges

Type of Waste Total Amount to 

be Discharged 

Discharge Rate Discharge Method 

*Sanitary Wastes 300,000 gals/well 25 gals per person 

daily 

Chlorinate and discharge overboard 

*Domestic waste 300,000 gals/well 25 gals per person 

daily 

Chlorinate and discharge overboard 

Deck drainage 210,000 bbls/well 3,500 bbls/day Treat for oil and grease and discharge 

Blowout preventer fluid 925 gals/week/well Vents on weekly 

basis 

Discharge at seafloor 

Desalinization Unit 21,000 bbls/well 350 bbls/day Discharge overboard 

Wash water 3,000 bbls/60 day 

well 

50 bbls/day Discharge overboard 

Ballast water As needed Not continuous Discharge overboard 

Bilge water 685 bbls/well 317 bbls/day Discharge overboard through 15 ppm 

equipment 

Excess cement at the 

seafloor 

451 bbls/well 20 bbls/min Discharge at seafloor 

Fire water 137,142 bbls/day N/A Discharge overboard 

Cooling water 137,142 bbls/day N/A Discharge overboard 

Cuttings wetted with 

water-based fluids 

23,166 bbls/well 1,000 bbls/hr max Discharge at seafloor 

Water-based drilling 

fluids 

63,000 bbls/well 1,000 bbls/hr max Discharge overboard or at seafloor 

Cuttings wetted with 

synthetic-based fluids 

2,300 bbls/well N/A Treated and discharge overboard 

Non-pollutant 

completion fluids 

5,000 bbls/well 100 bbls/hour Discharge overboard 

*The rig is designed for maximum personnel capacity of 200 people. The discharge rates are based off of maximum personnel 

capacity but will generally not have this many personnel onboard during drilling and/or completion operations. 

(c) Modeling Report 

The proposed activities under this plan do not meet the U.S. Environmental Protection Agency 

requirements for an individual NPDES permit. Therefore, modeling report requirements per 

NTL No. 2008-G04 is not applicable to this EP.
 

G 

AIR EMISSIONS INFORMATION 

(a) Screening Questions 

Screening Questions for EP’s Yes No

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

proposed exploration activities more than 90% of the amounts calculated using the 

following formulas: CT = 3400D2/3 for CO, and CT = 33.3D for the other air pollutants 

(where D = distance to shore in miles)? 

 No 

Do your emission calculations include any emission reduction measures or modified 

emission factors? 

 No 

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

Do you expect to encounter H2S at concentrations greater than 20 parts per million (ppm)? No 

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

proposed well? 

 No 

Do you propose to burn produced hydrocarbon liquids? No 

(b) Emissions Worksheets 

Air emissions worksheets have been prepared using a DP drillship and a DP semi-submersible 

drilling unit. Air emissions worksheets are included as Attachment G-1 for review. 

(c) Summary Information 

If drilled with a DP Drillship: 

Air Pollutant Plan Emission 

Amounts1

 (tons)

Calculated 

Exemption 

Amounts2

 (tons)

Calculated Complex 

Total Emission 

Amounts3 (tons)

Particulate matter (PM) 79.03 4,761.90 N/A 

Sulphur dioxide (SO2) 362.56 4,761.90 N/A 

Nitrogen oxides (NOx) 2,716.71 4,761.90 N/A 

Volatile organic compounds (VOC) 81.50 4,761.90 N/A 

Carbon monoxide (CO) 592.74 92,975.73 N/A 

If drilled with a DP Semi-submersible: 

Air Pollutant Plan Emission 

Amounts1

 (tons)

Calculated 

Exemption 

Amounts2

 (tons)

Calculated Complex 

Total Emission 

Amounts3 (tons)

Particulate matter (PM) 78.27 4,761.90 N/A 

Sulphur dioxide (SO2) 359.07 4,761.90 N/A 

Nitrogen oxides (NOx) 2,690.55 4,761.90 N/A 

Volatile organic compounds (VOC) 80.72 4,761.90 N/A 

Carbon monoxide (CO) 587.03 92,975.73 N/A 
 

The air emission calculations were calculated by: 

Bridget O’Farrell 

Regulatory Analyst 

(832) 636-1694 

Bridget.OFarrell-Villarreal@anadarko.com
EXPLORATION PLAN (EP)

AIR QUALITY SCREENING CHECKLIST

OMB A

COMPANY Anadarko Petroleum Corporation

AREA Lloyd Ridge

BLOCK 621LEASE G33323PLATFORMWELL A, B

COMPANY CONTACT Bridget O'FarrellTELEPHONE NO. 832-636-1694

REMARKS Drill and complete 2 wells 

Attachment G-1 (Drillship)

MMS FORM MMS-138 (December 2008 - Supersedes all previous versions of form MMS-138 which may not be used). Page 1 of 4
EMISSIONS FACTORS

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

SCF/hp-hr 9.524 SCF/hp-hr 7.143 GAL/hp-hr 0.0483 AP42 

Equipment/Emission Factors units PM SOx NOx VOC CO RENG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3.2-NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP42 NG 4-cycle lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP42 NG 4-cycle rich gms/hp-hr 0.00185 10 0.14 8.6 AP42 Diesel Recip. < 600 hp. gms/hp-hr 1 1.468 14 1.12 3.03 AP42 Diesel Recip. > 600 hp. gms/hp-hr 0.32 1.468 11 0.33 2.4 AP42 Diesel Boiler lbs/bbl 0.084 2.42 0.84 0.008 0.21 AP42 1.3NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 P42 1.4-1, 1NG Flares lbs/mmscf 0.593 71.4 60.3 388.5 AP42 1Liquid Flaring lbs/bbl 0.42 6.83 2 0.01 0.21 AP42 1.3-Tank Vapors lbs/bbl 0.03 E&P FFugitives lbs/hr/comp. 0.0005 API SGlycol Dehydrator Vent lbs/mmscf 6.6 La. DGas Venting lbs/scf 0.0034

Sulphur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.4 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

MMS FORM MMS-138 (December 2008 - Supersedes all previous versions of form MMS-138 which may not be used). Page 2 of 4
EMISSIONS CALCULATIONS 

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorLloyd Ridge 621 G33323 A, B Bridget O'Farrell 832-636-1694 

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

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

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

DRILLING PRIME MOVER>600hp diesel 61,800 2984.94 71638.56 24.00 150.00 43.56 199.83 1497.36 44.92 326.70 78.41 3Drillship PRIME MOVER>600hp diesel 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 PRIME MOVER>600hp diesel 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 AUXILIARY EQUIP<600hp diesel 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 2600 125.58 3013.92 6.00 64 1.83 8.41 63.00 1.89 13.74 0.35 2 trips/week VESSELS>600hp diesel(supply) 3000 144.9 3477.60 6.00 43 2.11 9.70 72.69 2.18 15.86 0.27 

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

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

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

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

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

MISC. BPD SCF/HR COUNTTANK- 0 0 0 0.00 

DRILLING OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 WELL TEST GAS FLARE 0 0 0 0.00 0.00 0.00 0.00 

2013 YEAR TOTAL 47.51 217.94 1633.04 48.99 356.30 79.03 3

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4761.90 47

143.0

MMS FORM MMS-138 (December 2008 - Supersedes all previous versions of form MMS-138 which may not be used). Page 3 of 4
SUMMARY

COMPANY AREA BLOCK LEASE PLATFORM 

Anadarko Petroleum Corporation Lloyd Ridge 621 G33323 

Emitted Substanc

Year

PM SOx NOx VOC 

2012 0.00 0.00 0.00 0.00 

2013 79.03 362.56 2716.71 81.50 

Allowable 4761.90 4761.90 4761.90 4761.90 

Drillship

MMS FORM MMS-138 (December 2008 - Supersedes all previous versions of form MMS-138 which may not be used). Page 4 of 4
EXPLORATION PLAN (EP)

AIR QUALITY SCREENING CHECKLIST

OMB A

COMPANY Anadarko Petroleum Corporation

AREA Lloyd Ridge

BLOCK 621LEASE G33323PLATFORMWELL A, B

COMPANY CONTACT Bridget O'FarrellTELEPHONE NO. 832-636-1694

REMARKS Drill and complete 2 wells

Attachment G-1 (DP Semi)

MMS FORM MMS-138 (December 2008 - Supersedes all previous versions of form MMS-138 which may not be used). Page 1 of 4
EMISSIONS FACTORS

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

SCF/hp-hr 9.524 SCF/hp-hr 7.143 GAL/hp-hr 0.0483 AP42 

Equipment/Emission Factors units PM SOx NOx VOC CO RENG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3.2-NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP42 NG 4-cycle lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP42 NG 4-cycle rich gms/hp-hr 0.00185 10 0.14 8.6 AP42 Diesel Recip. < 600 hp. gms/hp-hr 1 1.468 14 1.12 3.03 AP42 Diesel Recip. > 600 hp. gms/hp-hr 0.32 1.468 11 0.33 2.4 AP42 Diesel Boiler lbs/bbl 0.084 2.42 0.84 0.008 0.21 AP42 1.3NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 P42 1.4-1, 1NG Flares lbs/mmscf 0.593 71.4 60.3 388.5 AP42 1Liquid Flaring lbs/bbl 0.42 6.83 2 0.01 0.21 AP42 1.3-Tank Vapors lbs/bbl 0.03 E&P FFugitives lbs/hr/comp. 0.0005 API SGlycol Dehydrator Vent lbs/mmscf 6.6 La. DGas Venting lbs/scf 0.0034

Sulphur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.4 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

MMS FORM MMS-138 (December 2008 - Supersedes all previous versions of form MMS-138 which may not be used). Page 2 of 4
EMISSIONS CALCULATIONS 

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum Corporation Lloyd Ridge 621 G33323 A, B Bridget O'Farrell 832-636-1694 

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

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

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

DRILLING PRIME MOVER>600hp diesel 61,200 2955.96 70943.04 24 150 43.14 197.89 1482.82 44.48 323.52 77.65 DP Semi PRIME MOVER>600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

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

3 trips/week VESSELS>600hp diesel(crew) 2600 125.58 3013.92 6 64 1.83 8.41 63.00 1.89 13.74 0.35 2 trips/week VESSELS>600hp diesel(supply) 3000 144.9 3477.60 6 43 2.11 9.70 72.69 2.18 15.86 0.27 

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

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

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

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

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

MISC. BPD SCF/HR COUNTTANK- 0 0 0 0.00 

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

WELL TEST GAS FLARE 0 0 0 0.00 0.00 0.00 0.00 

2013 YEAR TOTAL 47.08 216.00 1618.50 48.56 353.13 78.27 

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4761.90 

143.0

MMS FORM MMS-138 (December 2008 - Supersedes all previous versions of form MMS-138 which may not be used). Page 3 of 4
SUMMARY

COMPANY AREA BLOCK LEASE PLATFORM 

Anadarko Petroleum Corporation Lloyd Ridge 621 G33323 

Emitted Substanc

Year

PM SOx NOx VOC 

2012 0.00 0.00 0.00 0.00 

2013 78.27 359.07 2690.55 80.72 

Allowable 4761.90 4761.90 4761.90 4761.90 

DP Semi

MMS FORM MMS-138 (December 2008 - Supersedes all previous versions of form MMS-138 which may not be used). Page 4 of 4
 

H 

OIL SPILL INFORMATION 

(a) Oil Spill Response Planning 

(i) OSRP Information 

All the proposed activities and facilities in this EP are covered by the Sub-Regional Oil Spill 

Response Plan (OSRP) approved on March 14, 2012 for Anadarko Petroleum Corporation and 

its subsidiaries, Kerr-McGee Oil & Gas Corporation and Anadarko E&P Company L.P. 

(Company Numbers 00981, 02219 and 00148, respectively) in accordance with 30 CFR Part 

254.

(ii) Spill Response Sites 

Primary Response Equipment Location(s) Preplanned Staging Location(s) 

Galveston, Texas 

Fourchon, Louisiana 

Harvey, Louisiana 

Houma, Louisiana 

Leeville, Louisiana 

Venice, Louisiana 

Galveston, Texas 

Fourchon, Louisiana 

Harvey, Louisiana 

Fourchon, Louisiana 

Leeville, Louisiana 

Venice, Louisiana 

(iii) OSRO Information 

Anadarko maintains a contract with Clean Gulf Associates (CGA) for spill response equipment. 

Various equipment locations are staged throughout the Gulf of Mexico. CGA equipment can be 

referenced on their website: http://www.cleangulfassoc.com/. Personnel would be obtained from 

the Marine Spill Response Corporation’s (MSRC) STARS network, including a supervisor to 

operate the equipment. 

In addition Anadarko has a contract with the Marine Spill Response Corporation (MSRC) for 

spill response equipment. MSRC stages equipment throughout the Gulf of Mexico and has 

recently completed a large expansion of its resources, with particular focus on deepwater. The expansion 

is known as “Deep Blue”. MSRC capabilities and a complete equipment listing are available online at: http://www.msrc.org/. 

Anadarko is a member of the Helix Well Containment Group (HWCG), a combination of the 

Helix Fast Response System (HFRS) and the common equipment and services. This agreement 

allows access to subsea well containment and well shut-in equipment. 

Anadarko is also a member of the Marine Well Containment Company (MWCC), which 

provides access to containment response capabilities and includes subsea dispersant injection 

equipment. 
 

(iv) Worst-Case Scenario Determination 

Category Sub-Regional OSRP EP 

Type of Activity Exploratory Exploratory 

Facility Location (area/block) DC 490 LL 621 

Facility Designation Location “C” #1 (Location “A”) 

Distance to Nearest Shoreline 95 Miles 143 miles 

 Storage Tanks (total) N/A N/A 

 Flowlines (on facility) N/A N/A 

 Pipelines N/A N/A 

 Uncontrolled Blowout 347,431 bbls 627 bbls 

Type of Oil(s) Crude Condensate 

API Gravity 41o 25.5o

Anadarko has determined that the worst-case scenario from the activities proposed in this Initial 

EP does not supersede the worst-case scenario for DeSoto Canyon Block 490 as previously filed 

in the Sub-Regional OSRP. 

Since Anadarko has the capability to respond to the worst-case spill scenario included in our 

Sub-Regional OSRP approved on March 14, 2012, and since the worst-case discharge scenario 

determined for our EP does not replace the appropriate worst-case scenario in our Sub-Regional 

OSRP, I hereby certify that Anadarko has the capability to respond, to the maximum extent 

practicable, to a worst-case discharge, or a substantial threat of such a discharge, resulting from 

the activities proposed in our EP. 

(b) Worst-Case Discharge Volume Assumptions 

Worst-case discharge (WCD) calculations and assumptions within this section utilized guidelines 

and requirements pursuant with NTL No. 2010-N06. Discussions regarding geologic information 

are considered proprietary and have been omitted from this public copy of the EP. 

(c) Oil Spill Response Discussion

For the purpose of NEPA analysis, the largest spill volume originating from the proposed 

activity would be the loss of the single largest fuel tank on a drillship during drilling operations 

at 16,685.5 barrels of diesel fuel with an API gravity of 32.4o

. A discussion of the blowout 

scenario from this proposed activity is included within this Initial EP in accordance with NTL 

No. 2010-N06. 
 

Land Segment and Resource Identification Modeling

Trajectory of a spill and the probability of its impacting a land segment have been projected 

utilizing information in the Oil Spill Risk Analysis Model (OSRAM) for the Central Gulf of 

Mexico. Additional information may be referenced in the “Oil Spill Risk Analysis: Contingency 

Planning Statistics for Gulf of Mexico OCS Activities” (OCS Report MMS 2004-026), using the 

average conditional probability for 3, 10, and 30 day impacts. 

Lloyd Ridge Block 621 is located within Launch Area 139. According to the OSRAM, the 

trajectory indicates a 2% probability of potential impact to the shoreline in Plaquemines Parish, 

Louisiana. The results are shown in Table H-2.

Plaquemines Parish is identified as the most probable potential impacted parish or county within 

the Gulf of Mexico for this operation. Plaquemines Parish is located in Louisiana and includes 

Delta National Wildlife Refuge (NWR) and Pass-a-Loutre Wildlife Management Area (WMA), 

and Bohemia WMA. 

Response 

Anadarko will make every effort to respond to the worst-case discharge as effectively as 

possible. Response equipment available to respond to the worst-case discharge and the estimated 

time of a spill response from oil spill detection to equipment deployment on-site is included in 

Table H-3. The table estimates individual times needed for procurement, load out, travel time to 

the site and deployment. In the event of an actual incident equipment and times can vary. 

For the purpose of response scenario discussion, the loss of the single largest fuel storage would 

be considered the largest potential spill volume at 16,685.5 barrels of diesel fuel. An ADIOS 

weathering model was run based on a similar type of oil expected to be produced from this well. 

Based on this information, approximately 37% (6,173 bbls) of the initial volume would be 

evaporated/dispersed within 24 hours. 

If approved and appropriate, 4 sorties (8,000 gallons) from the Basler aircraft and 8 sorties 

(9,600 gallons) from two DC-3 aircrafts could disperse approximately 7,540 barrels of oil. 

If the conditions are appropriate, and the necessary approvals and permits have been obtained, 

in-situ burning may be utilized. Based on in-situ burn operations during Deepwater Horizon, 

approximately 5% (526 bbls) of the worst case discharge volume after natural 

evaporation/dispersion. 

Although unlikely in a spill lasting 30 days, potential shoreline impact in Plaquemines Parish, 

Louisiana could occur depending on environmental conditions (wind, currents and temperature) 

at the time of an incident. Nearshore response may include the use of shoreline boom on beach 

areas, or protection/sorbent boom on vegetated areas. Surveillance and real time trajectories 

would aide in determining the most appropriate strategies to respond to a spill. 
 

Table H.3 provides an example of offshore and nearshore equipment, response times, and 

personnel to respond to a spill of 10,512.5 barrels, which is the estimated amount that would 

remain considering natural evaporation/dispersion at 24 hours. This amount could be further 

reduced through the application of aerial and subsea dispersants, provided such applications were 

approved. 

Anadarko’s contingency plan for dealing with this worst-case discharge would be to activate 

its Spill Management Team and equipment resources as described in its Gulf of Mexico 

Sub-Regional Oil Spill Response Plan (OSRP) and provide continuous support for the duration 

of the event. Response resources are activated and supplemented according to need. These 

resources would remain engaged in the response until the incident is deemed complete or until 

released by Unified Command. 

Anadarko is a member of the Helix Well Containment Group (HWCG), a combination of the 

Helix Fast Response System (HFRS) and the common equipment and services. This agreement 

allows access to subsea well containment and well shut-in equipment. 

Anadarko is also a member of the Marine Well Containment Company (MWCC), which 

provides access to containment response capabilities and includes subsea dispersant injection 

equipment. 

In the event of a blowout, Anadarko may: 

 1. Evacuate personnel, if necessary. Deploy emergency responders in an effort to preserve 

human life, if necessary. 

 2. Assess the damage and attempt to stop the flow at the source, if safe to do so, to reduce 

the amount of oil discharged. 

 3. Notify agencies. 

 4. Assess the amount of oil that has been spilled and calculate additional potential of oil 

flow. A continuous aerial surveillance program would be used to assess the growth of the 

slick and the volume of oil on the water. Observations of the size of the slick on the 

water, combined with observations at the source, would be used to provide a constant 

update. Additional potential to release fuel from the remaining tanks onboard the 

appropriate DP drillship or DP semi-submersible drilling rig would be determined by 

marine surveyors. Operations and Unified Command would continue to assess the 

adequacy of response equipment capacities based on this continually updated mass 

balance. 

 5. Convene the Spill Management Team (SMT). Organize Unified Command and establish 

objectives and priorities. 

 6. Monitor the oil spill with aerial surveillance and obtain trajectories. If oil is seaward 

bound, going away from land, discuss additional strategies with Unified Command. 
 

 7. If oil is moving in the direction of a shoreline and weather conditions are favorable, 

request approval to utilize dispersants. 

 a. Prior to commencing application operations, conduct an on-site survey in consultation 

with natural resource specialists to determine if any threatened or endangered species 

are present in the projected application area or otherwise at risk from dispersant 

application. 

 b. Upon approval, mobilize one Basler aircraft and two DC-3 aircrafts from Houma if 

needed, with surveillance aircraft and spotter. Rotate aircraft, spraying the leading 

edge of the spill and working back to the source. Monitor/sample for effectiveness 

(USCG SMART Team). Truck additional dispersants from CGA stockpile to Houma, 

if necessary. 

 c. Dispersants are most effective when applied as soon after discharge as possible, since 

weathering of the oil decreases dispersant effectiveness. The estimated window of 

opportunity for most effective use of dispersants is within 48-72 hours post-release. 

The oil may still be dispersible after 72 hours on the water surface, but the 

effectiveness of dispersant use would likely be diminished after the oil has been on the 

water for more than three days. Ultimately, the USCG SMART monitoring protocol 

will be used to determine whether or not dispersant operations are effective. 

 d. Once the CGA HOSS barge is on location and in the skimming mode, dispersants 

would only be used if required and approved. 

 8. Deploy offshore mechanical oil containment and recovery equipment. Attempt to recover 

as much oil at sea as possible, utilizing: 

 a. The CGA HOSS barge, will be positioned in a stationary mode, will be situated downwind and down-current from location for long-duration, high-volume skimming. 

Based on average travel times, the HOSS barge could be on location within 

approximately 37 hours of the release. The de-rated skimming capacity of the HOSS 

barge is 43,000 bbls per day. However, only the oil encountered by a skimmer can be 

recovered. In order to maximize oil encounter rate, boom will be deployed in a 

V-configuration in front of the HOSS barge to funnel oil to the skimmers. If 

necessary, temporary barges can be activated to support continuous skimming 

operations. (These barges arrive on-site at approximately the same time as the HOSS 

barge.) For an on-going release, multiple barges are deployed to provide for 

continuous off-loading of skimmer storage vessels and shuttling of recovered oil to an 

onshore waste handling facility. Sufficient barges are available to provide enough 

temporary storage for continuous recovery operations. 

 b. CGA’s Fast Response Units (FRU) could arrive on-scene between approximately 

15.2-19.4 hours of the initial release. These skimmers operate downstream of the 

HOSS barge and are used to recover pockets and streamers of oil that may move past 
 

the large stationary skimmer. Each FRU has 200 barrels of on-board storage. 

Approval will be requested to decant water after gravity separation, through a hose 

forward of the skimmer, to optimize temporary storage capacity. A 42" Boom will be 

utilized to concentrate oil so that it is thick enough to be skimmed. 

 9. Dispersants, Fast Response Units (FRU), and Oil Spill Response Vessels (OSRV) would 

typically work daylight hours only. The HOSS barge can operate continuously, including 

night operations. Available technology will be considered such as remote sensing devices 

that will enable 24 hour surveillance, trajectories, and planning. All response vessels are 

designed to be able to remain offshore continuously throughout the response. Even if sea 

conditions prohibit effective skimming, these resources would remain offshore until 

skimming operations could be commenced again. Safety would remain the first priority. 

 10. Prepare Site-Specific Waste Management Plan, Site Safety Plan, Decontamination Plans, 

Communications and Medical Plans. 

 11. If oil becomes a threat to any shoreline, data from the aerial surveillance, weather reports, 

and trajectories would be used to direct onshore teams to deploy protection/containment 

boom with reference to Area Contingency Plans and in coordination with State and 

Federal On-Scene Coordinators. 

 a. Implement pre-designated strategies. 

 b. Identify resources at risk in spill vicinity. 

 c. Develop/implement appropriate protection tactics. 

 12. Establish Site-Specific Wildlife Rescue and Rehabilitation Plan. 

Anadarko has the capability to respond and contain, to the maximum extent practicable as 

defined in 30 CFR 254.6 and 30 CFR 250.26(d)(1), to the estimated worst case discharge (WCD) 

associated with the proposed activity within 30 days. Deployment time for surface containment 

equipment is subject to availability and location, weather conditions, potential security zones 

around the spill site, and site/well specific assessment data. Personnel safety is always first and 

foremost. Refer to further details on equipment and timing provided in Section H–Oil Spill 

Information and Table H-3 of the EP. 

There will be no new or unusual technology deployed that has not been previously deployed in 

regards to Gulf of Mexico oil spill prevention, control, and/or cleanup. 

The potential WCD will be further evaluated during the Application for Permit to Drill (APD) 

process, including the Well Containment Screening Tool (WCST) and associated subsea 

containment plan for enhanced planning purposes. 
 

The following types of additional support may be required for a blowout lasting 120 days. 

 Additional Oil Spill Removal Organization (OSRO) personnel to relieve equipment 

operators 

 Vessels for supporting offshore operations 

 Field safety personnel 

 Continued surveillance and monitoring of oil movement 

 Helicopter, video cameras 

 Infra red (night time spill tracking) capabilities, X-band radar 

 Barge to transport recovered oil from offshore skimming system, and temporary 

storage barges to onshore disposal sites that are identified in Area Contingency Plans 

(ACP) 

 Logistics needed to support equipment: 

- Staging areas 

- Parts, trailers, and mechanics to maintain skimmers and boom 

- Fueling facilities 

- Decontamination stations 

- Dispersant stockpile transported from Houston to Houma or other potential 

command post locations 

- Communications equipment and technicians 

 Logistics needed to support responder personnel 

- Medical aid stations 

- Safety personnel

- Food 

- Berthing 

- Additional clothing/safety supplies 

- Decontamination stations 
 

Table H-1 

Worst Case Discharge Calculation 

(Based on Loss of Single Largest Fuel Storage Tank during Drilling Operations)

Calculations for Loss of Single Largest Fuel Storage Tank on Rig (Drillship) Block 621 

 i. Type of Oil (crude, condensate, diesel) Diesel 

 ii. API Gravity 32.4 ̊

 iii. EP Location Used for NTL No. 2010-N06 WCD for LL 621 IEP location #1 

(Location “A) 

 iv. Largest Anticipated WCD Rate during blowout 16,685.5 bbls 

 v. WCD Total for Drilling Operations for LL 621 (> 10 miles from shore): 16,685.5 bbls 
 

Table H-2 

Trajectory by Land Segment 

Following are the average conditional probabilities (expressed as percent chance) that an oil spill starting at a 

particular launch area will contact a land segment as included in the Oil Spill Risk Analysis Model (OSRAM) for 

the Eastern Gulf of Mexico. This information can be found on the BSEE website using 3/10/30 day potential impact, 

as applicable. The results are listed below. 

Area/Block/ 

Location OCS-G Launch Area Land Segment and/or Resource 

Conditional Probability (%) 

3 

days 

10 

days 

30 

days 

Lloyd Ridge 621 

#1 (Location “A”) 

Drilling 

(95 miles from 

shore) 

G33323 LA 139 

Eastern 

Planning 

Area 

Terrebonne Parish, LA 

Lafourche Parish, LA 

Jefferson Parish, LA 

Plaquemines Parish, LA 

St. Bernard Parish, LA 

Hancock & Harrison County, MS 

Jackson County, MS 

Mobile County, AL 

Baldwin County, AL 

Escambia County, FL 

Santa Rosa County, FL 

Okaloosa County, FL 

Walton County, FL 

Bay County, FL 

Gulf County, FL 

Franklin County, FL 

Taylor County, FL 

Wakulla County, FL 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

1 

1 

-- 

2 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 
Table H-3 

WCD Scenario Drilling Activities – Based on a loss of the single largest fuel storage tank on a drillship (95 miles from shore)Lloyd Ridge Block 621 #1 (“Location “A”) 16,685.5 bbls of diesel fuel (initial volume) 10,512.5 bbls (after evaporation/dispersion) API Gravity 32.4o 

Offshore Equipment from Spill Detection to Equipment Deployment Response Time: Lloyd Ridge Block 621 #1 (L

Offshore Equipment 

Owner/Location Initial Staging 

Hours to 

Staging 

Area 

Time to 

Procure 

(1) 

Time 

to 

Load Out 

(2) 

Tra

Tim

(Stag

Spi

(3

Type 

Derated 

Capacity 

(bbls) 

Storage 

(bbls) 

No. of 

Units/ 

Persons 

Basler Spray Aircraft DC 3 Spray Aircraft Aero Commander 

-- -- 

-- -- 

1 2 2 

ASI/Houma Houma 

0 0 1 1 1 1.

HOSS Barge Operators Tugs 

43,000 4,000 1 

8 3 

CGA/Harvey STARS VOO 

Harvey 

1 2 4 4 0 33 

FRU Operators Utility Boat 

3,770 200 1 

6 1 

CGA/Harvey STARS VOO 

Harvey 

.5 

2 2 1 2 15

FRU Operators Utility Boat 

7,540 400 2 

12 

2 

CGA/Venice STARS VOO 

Venice 

0 2 2 1 2 11

FRU Operators Utility Boat 

7,540 400 2 

12 

2 

CGA/Leeville STARS VOO 

Leeville 

.5 

2 2 1 2 13

Koseq Skimming Arms Operators Vessel w/ storage/hull 

17,829 500 1 set 

6 1 

CGA/Fourchon STARS VOO 

Fourchon 

0 2 2 1 12 13 

Deep Blue Responder LFF 100 Brush + OSRV 6,600’ 44” Sea Sentry Boom 660’ 67” LAMOR 

18,086 4,000 1/14 crew 

1 1 1 

MSRC/Fourchon MSRC/Fourchon MSRC/Fourchon MSRC/Fourchon 

Fourchon 

0 2 2 2 2 0 16.

CTCo 5001 Operators Tug 

-- 47,000 1 

6 1 

EMS/Amelia STARS VOO 

Amelia 

0 2 4 4 0 43

CTCo 2607 Operators Tug 

-- 23,000 1 

6 1 

EMS/Amelia STARS VOO 

Amelia 

0 2 4 4 0 43

Spill Team Area Responders (STARS) called out by Marine Spill Response Corporation (MSRC) Vessel of Opportunity=VOO EMS=Enterprise Marine Services
Offshore Equipment, cont. 

Owner/Location Initial Staging 

Hours to 

Staging 

Area 

Time to 

Procure 

(1) 

Time 

to 

Load Out 

(2) 

Trav

Tim

(Stagi

Spil

(3) 

Type 

Derated 

Capacity 

(bbls) 

Storage 

(bbls) 

No. of 

Units/ 

Persons 

CTCo 2608 Operators Tug 

-- 23,000 1 

6 1 

EMS/Amelia STARS VOO 

Amelia 

0 2 4 4 0 43.6 

10,000' 42" Auto Boom VOO 

-- -- 40 

20 crew 

CGA/Harvey STARS Harvey .5 2 1 2 15.4 

5,000' 42" Auto Boom VOO 

-- -- 20 

10 crew 

CGA/Lake Charles STARS Cameron .5 2 1 2 26 

2,500' 42" Auto Boom VOO 

-- -- 12 

6 crew 

CGA/Pascagoula STARS Pascagoula 0 2 1 2 14.3 

22,400' 42" Boom VOO 

-- -- 80 

25 crew AMPOL/New Iberia New Iberia 0 2 1 2 20.7 

4,800' 42" Boom VOO 

-- -- 18 

9 crew AMPOL/Harvey Harvey 0 2 1 2 15.4 

Spotter Helo Surveillance Helo Hand Held Radios 

-- -- -- 

-- -- -- 

1 1 

30 

PHI/Fourchon PHI/Fourchon STARS 

Spill Site Spill Site Fourchon 

1 1 

1.5 

1 1 

1.5 

-- -- -- 

2 2 1 

Total 97,765 102,500 
Nearshore Equipment from Spill Detection to Equipment Deployment Response Time: Lloyd Ridge Block 621 #1 (L

Nearshore Equipment* 

Owner/Location Initial Staging 

Hours to 

Staging 

Area 

Time to 

Procure 

(1) 

Time 

to 

Load Out 

(2) 

Trave

Time 

(Stagin

Spill) 

(3) 

Type 

Derated 

Capacity 

(bbls) 

Storage 

(bbls) 

No. of 

Units/ 

Persons 

Basler Spray Aircraft DC 3 Spray Aircraft Aero Commander 

-- -- 1 

2 2 

ASI/Houma Houma 

0 0 1 1 1 .5 

SWS Egmopol Operators 

3,000 100 1 

3 

CGA/Galveston STARS Galveston 0 2 1 2 75.6 

SWS Egmopol Operators 

3,000 100 1 

3 

CGA/Morgan City STARS Morgan City .5 2 1 2 45.1 

SWS Marco Operators 

3,588 34 1 

3 

CGA/Leeville STARS Leeville .5 2 1 2 17 

SWS Marco Operators 

3,588 20 1 

3 

CGA/Lake Charles STARS Cameron .5 2 1 2 32.5 

R/V Grand Bay Operators 

5,000 65 1 

3 

CGA/Venice STARS Venice .5 2 2 .5 7.3 

R/V RW Armstrong Operators 

5,000 65 1 

3 

CGA/Leeville STARS Leeville .5 2 2 .5 9 

R/V Bastian Bay Operators 

5,000 65 1 

3 

CGA/Lake Charles STARS Cameron .5 2 2 .5 17 

R/V Timbalier Bay Operators 

5,000 65 1 

3 

CGA/Galveston STARS Galveston 0 2 2 .5 19.7 

CTCo 2604 Operators Tugs 

-- 20,000 1 

6 1 

EMS/Amelia Amelia 

0 2 4 4 0 21 

CTCo 2605 Operators Tugs 

-- 20,000 1 

6 1 

EMS/Amelia Amelia 

0 2 4 4 0 21 

2,000' Beach Boom -- -- 6 CGA/Galveston Galveston 0 1 2 12 1,000' Beach Boom -- -- 4 CGA/Ingleside Ingleside 0 1 2 15 2,000' Beach Boom -- -- 6 CGA/Pascagoula Pascagoula 0 1 2 7 10,000' 18" Boom VOO 

-- -- 10 

4 crew Oil Mop/New Iberia New Iberia 0 2 1 1 8 

10,000' 18" Boom VOO 

-- -- 10 

4 crew Oil Mop/Houston Houston 1 2 1 1 12.5 

10,000' 18" Boom VOO 

-- -- 10 

4 crew Oil Mop/Houma Fourchon .5 2 1 1 6 

20,000' 18" Boom VOO 

-- -- 20 

8 crew Oil Mop/Belle Chasse Venice .5 2 1 1 5.5 

15,000' 18" Boom VOO 

-- -- 14 

6 crew Oil Mop/Gretna Gretna 0 2 1 1 5.75 
Nearshore Equipment, cont. 

Owner/Location Initial Staging 

Hours to 

Staging 

Area 

Time to 

Procure 

(1) 

Time 

to 

Load Out 

(2) 

Trave

Time 

(Stagin

Spill) 

(3) 

Type 

Derated 

Capacity 

(bbls) 

Storage 

(bbls) 

No. of 

Units/ 

Persons 

22,700' 18" Boom VOO 

-- -- 8 

24 crew AMPOL/Harvey Harvey 0 2 0 1 5.8 

Wildlife Support Trailer -- -- 1/2 crew CGA/Harvey Harvey .5 1 2 5.8 Bird Scare Cannons -- -- 2 CGA/Venice Venice .5 1 2 4.2 Bird Scare Cannons -- -- 1 CGA/Galveston Galveston 0 1 2 11.35 Bird Scare Cannons -- -- 2 CGA/Harvey Harvey .5 1 2 5.8 Bird Scare Cannons -- -- 2 CGA/Pascagoula Pascagoula 0 1 2 5.3 Spotter Helo Surveillance Helo Hand Held Radios 

-- -- -- 

-- -- -- 

1 1 

30 

PHI/Fourchon PHI/Fourchon STARS 

Spill Site Spill Site Fourchon 

1 1 

1.5 

1 1 

1.5 

-- -- -- 

.5 .5 

1 

Total 33,176 40,514 

*Some equipment may be used offshore up to approximately 25 miles from shore 
 

H-3 (continued) 

Operational Limitations of Response Equipment 

 HOSS Barge/Oil Spill Response Barge (OSRB)–8 foot seas 

 Fast Response Unit (FRU)–8 foot seas 

 Oil Spill Response Vessel (OSRV)–4 foot seas 

 Koseq Arms–8 foot seas 

 Boom–3 foot seas, 20 knot winds 

 Dispersants–winds more than 25 knots, visibility less than 3 nautical miles or ceiling less than 

1,000 feet 
 

I 

Environmental Monitoring and Environmental Mitigation Measures 

(a) Monitoring 

If required, Anadarko will monitor loop currents per NTL 2009-G02. 

Anadarko subscribes to Wilkins Weather Service which provides real-time weather 

conditions such as tropical depressions, storms and/or hurricanes entering the Gulf. 

Additional measures to avoid, minimize, and mitigate environmental impacts is included 

in Section N–Environmental Impact Analysis. 

(b) Incidental Takes 

Although marine mammals may be seen in the area, Anadarko does not believe that its 

operations proposed under this EP will result in the harassment, capture, collection or 

killing of any mammals covered by the Marine Mammal Protection Act. 

Anadarko will operate in accordance with applicable regulations in order to avoid or 

minimize incidental takes of marine mammals and other species, including: 

 Joint NTL No. 2012-G02 “Implementation of Seismic Survey Mitigation 

Measures and Protected Species Observer Program” 

 BSEE NTL No. 2012-G01 “Marine Trash and Debris Awareness and 

Elimination”, and 

 Joint NTL No. 2012-G01 “Vessel Strike Avoidance and Injured/Dead Protected 

Species Reporting” 
 

J 

LEASE STIPULATIONS INFORMATION 

Stipulation No.3 (Lease Sale 208)–Military Areas 

Lloyd Ridge Block 621 is located within Military Warning Area EWTA-3 (Eglin Water 

Test Area 3). The EWTA-3 Air Armament Center will be contacted in order to 

coordinate and control electromagnetic emissions, possible evacuations of personnel, and 

shut-in operations during the proposed activities. Anadarko will notify the BOEM and/or 

BSEE as appropriate and EWTA-3, prior to conducting operations, of the person to be 

notified to implement the terms of this stipulation. The EWTA-3 is located at: 

101 West D Ave., Suite 227 

Eglin AFB, Florida 32542-5492 

Stipulation No.5 (Lease Sale 208)–Coordination 

Operators must coordinate approved proposed activities with the BOEM/BSEE to 

minimize conflicts with Department of Defense activities. The stipulation allows for the 

conditional approval of proposed operations in the interest of national security or defense, 

or to minimize the effects of conflicts with potentially hazardous military operations. 
 

K 

Support Vessels and Aircraft Information 

(a) General 

Type Max. Total Fuel 

Tank Storage 

Capacity 

Max. No. in Area 

at any Time 

Trip Frequency or 

Duration 

Supply Vessel 336,227 gallons 1 2 trips/week 

Helicopter 735.3 gallons 1 10 trips/week 

Crew Vessel 50,000 gallons 1 3 trips/week 

Tug Boats N/A N/A N/A 

(b) Diesel Oil Supply Vessels 

Fuel for the rig will be transported via a supply vessel as follows: 

a. Size of fuel supply vessel: 230 feet 

b. Carrying capacity of fuel supply vessel: 336,227 gallons 

c. Frequency that fuel supply vessel will visit the 

facilities: once per week 

d. Routes the fuel supply vessel will use to travel 

between the onshore support base and proposed 

facility: 

6 miles from Port Fourchon to the mouth of 

Bayou Lafourche, then approximately 190 

miles to LL 621. 

(c) Drilling Fluids Transportation 

The following estimates were prepared utilizing Anadarko’s experience with similar drilling 

operations. Estimated quantities are reflected in the table below.

Type of Material Quantity Being Transported Transportation Method 

Water-based drilling fluid 

(NaCl saturated, seawater, 

freshwater, barite) for Pump 

and Dump 

13 gallon tote tanks (liquids) 

40-63 sacks on pallet (sack 

chemicals) 

Supply boat 

Synthetic-based drilling fluid 

(internal olefin, ester) 

13 gallon tote tanks (liquids) 

40-63 sacks on pallet (sack 

chemicals) 

Supply boat 

Oil-based drilling fluid N/A N/A 

 
 

(d) Solid and Liquid Wastes Transportation 

Type of 

Waste 

Composition Total 

Projected 

Amount 

Rate Transport 

Method 

Name/Location of 

Facility 

Disposal 

Method 

Syntheticbased 

drilling fluid 

or muds

Synthetic-based 

drilling muds

26,000 bbls 13,000 

bbls/well

Re-use 

and/or 

transport to 

shore in 

tanks. 

Waste - Port Fourchon, 

LA and on to Newpark 

Fourchon Transfer Station 

#1 & #2. Newpark 

Transfer Station Morgan 

City. Newpark Transfer 

Station Port Arthur. USLL 

Galveston and Fourchon 

Transfer Station. If 

recycled, returned to 

vendor (Bariod or MI).

Re-used and/or 

recycled; if can’t 

be reused and/or 

recycled the 

waste is disposed 

of at Newpark 

(injection 

disposal facility) 

or USLL 

(landfarm). 

Cuttings 

wetted with 

syntheticbased muds

Cuttings coated 

with synthetic 

drilling muds, 

including drilled 

out cement

230-460 

bbls

115-230 

bbls/well* 

*An estimated 

5-10% of 

cuttings may 

be transported 

to shore 

Re-use 

and/or 

transport to 

shore in 

tanks and/or 

cutting 

boxes. 

Waste - Port Fourchon, 

LA and on to Newpark 

Fourchon Transfer Station 

#1 & #2. Newpark 

Transfer Station Morgan 

City. Newpark Transfer 

Station Port Arthur. USLL 

Galveston and Fourchon 

Transfer Station. If 

recycled, returned to 

vendor (Bariod or MI).

Re-used and/or 

recycled; if can’t 

be reused and/or 

recycled the 

waste is disposed 

of at Newpark 

(injection 

disposal facility) 

or USLL 

(landfarm). 

Chemical 

product 

waste (well 

treatment 

fluids) 

Ethylene glycol 

Methanol 

1,000 bbls 

250 bbls 

100 

bbls/month 

25 

bbls/month 

Transport 

to shore in 

drums 

and/or tote 

tanks for 

pick up 

Chemwaste in Sulphur, 

LA and Veolia Port 

Arthur, TX or to 

Newpark, Port Arthur as 

non-hazardous waste. 

Can be returned 

to vendor and/or 

used at another 

facility; MEG is 

solidified and 

disposed of in a 

landfill. 

Methanol is 

incinerated or 

used for fuels 

blending. 

Completion 

fluids 

Brine, spent 

acid, prop 

sand, debris 

6,000 bbls 3,000 

bbls/well 

Transport 

to shore in 

cuttings 

boxes, 

drums, 

and/or 

vessel tanks 

for pick up 

Sent to Port Fourchon, 

LA and on to Newpark 

Fourchon Transfer 

Station #1 & #2. 

Newpark Transfer 

Station Morgan City. 

Newpark Transfer 

Station Port Arthur. 

USLL Galveston and 

Fourchon Transfer 

Station 

Unused brine 

can be returned 

to vendor and/or 

stored for use 

on another job. 

Used brine and 

spent acid is 

transferred to 

Newpark's 

Processing & 

Transfer facility 

for injection. 

Workover 

fluids 

Brine, spent 

acid, prop 

sand, debris 

6,000 bbls 3,000 

bbls/well 

Transport 

to shore in 

cuttings 

boxes, 

drums, 

and/or 

Sent to Port Fourchon, 

LA and on to Newpark 

Fourchon Transfer 

Station #1 & #2. 

Newpark Transfer 

Station Morgan City. 

Unused brine 

can be returned 

to vendor and/or 

stored for use 

on another job. 

Used brine and 
 

vessel tanks 

for pick up 

Newpark Transfer 

Station Port Arthur. 

USLL Galveston and 

Fourchon Transfer 

Station 

spent acid is 

transferred to 

Newpark's 

Processing & 

Transfer facility 

for injection. 

Trash and 

debris 

Refuse 

generated 

during 

operations 

250 bbls 50 

bbls/month 

Transport 

to shore in 

disposal 

bags by 

vessel to 

shorebase 

for pickup 

by 

municipal 

operations 

Recycled Material in 

ARC, New Iberia, LA. 

Trash disposed of at 

SWDI landfill. 

Recycled and/or 

disposed in 

landfill. 

Used oil Excess oil from 

engines 

538 bbls 430 

bbls/120 

days 

Transport 

in totes to 

shore for 

pick up 

American Recovery 

Fourchon, LA 

Recycled 

*Total projected amount assumes 2 wells at 75 days/well 

(e) Vicinity Map 

A vicinity map is included in this section as Attachment K-1. 
Lloyd Ridge Block 621 

Environmental Impact Analysis for Initial Exploration Plan 

Figure 1. Location of Lloyd Ridge Block 621.
 

L 

ONSHORE SUPPORT FACILITIES INFORMATION

(a) General 

Per NTL No. 2008-G04, the following tables reflect the onshore facilities Anadarko will 

utilize to provide supplies and service support for the activities proposed in this 

Exploration Plan. 

 

Name Primary Location Existing/New/Modified 

Anadarko Service Base Fourchon, Louisiana Existing 

Name *Alternate Locations Existing/New/Modified 

Anadarko Service Base Galveston, TX Existing 

Anadarko Service Base Cameron, LA Existing 

Anadarko Service Base Pascagoula, MS Existing 

*In the unlikely event Anadarko’s primary service base cannot be utilized Anadarko will exercise the 

use of an alternate service base during drilling and/or completion operations. 

(b) Support Base Construction or Expansion 

No onshore support base construction or expansion is planned for these activities. 

Therefore dredging or filling activities associated with construction or expansion of 

facilities will not be applicable. 

(c) Support Base Construction or Expansion Timetable 

Since no onshore support base construction or expansion is planned for these activities, a 

timetable for land acquisition and construction or expansion is not applicable. 

(d) Waste Disposal 

Disposed wastes describe those wastes generated by the proposed activity that are 

disposed of by means other than by release into the water of the GOM at the site where 

they are generated. These wastes can be disposed of by offsite release, injection, 

encapsulation, or placement at either onshore or offshore permitted locations for the 

purposes of returning them back to the environment. 
 

Type of 

Waste 

Composition Total 

Projected 

Amount 

Rate Transport 

Method 

Name/Location of 

Facility 

Disposal 

Method 

Syntheticbased 

drilling fluid 

or muds

Synthetic-based 

drilling muds

26,000 bbls 13,000 

bbls/well

Re-use 

and/or 

transport to 

shore in 

tanks. 

Waste - Port Fourchon, 

LA and on to Newpark 

Fourchon Transfer Station 

#1 & #2. Newpark 

Transfer Station Morgan 

City. Newpark Transfer 

Station Port Arthur. USLL 

Galveston and Fourchon 

Transfer Station. If 

recycled, returned to 

vendor (Bariod or MI).

Re-used and/or 

recycled; if can’t 

be reused and/or 

recycled the 

waste is disposed 

of at Newpark 

(injection 

disposal facility) 

or USLL 

(landfarm). 

Cuttings 

wetted with 

syntheticbased muds

Cuttings coated 

with synthetic 

drilling muds, 

including drilled 

out cement

230-460 

bbls

115-230 

bbls/well* 

*An estimated 

5-10% of 

cuttings may 

be transported 

to shore 

Re-use 

and/or 

transport to 

shore in 

tanks and/or 

cutting 

boxes. 

Waste - Port Fourchon, 

LA and on to Newpark 

Fourchon Transfer Station 

#1 & #2. Newpark 

Transfer Station Morgan 

City. Newpark Transfer 

Station Port Arthur. USLL 

Galveston and Fourchon 

Transfer Station. If 

recycled, returned to 

vendor (Bariod or MI).

Re-used and/or 

recycled; if can’t 

be reused and/or 

recycled the 

waste is disposed 

of at Newpark 

(injection 

disposal facility) 

or USLL 

(landfarm). 

Chemical 

product 

waste (well 

treatment 

fluids) 

Ethylene glycol 

Methanol 

1,000 bbls 

250 bbls 

100 

bbls/month 

25 

bbls/month 

Transport 

to shore in 

drums 

and/or tote 

tanks for 

pick up 

Chemwaste in Sulphur, 

LA and Veolia Port 

Arthur, TX or to 

Newpark, Port Arthur as 

non-hazardous waste. 

Can be returned 

to vendor and/or 

used at another 

facility; MEG is 

solidified and 

disposed of in a 

landfill. 

Methanol is 

incinerated or 

used for fuels 

blending. 

Completion 

fluids 

Brine, spent 

acid, prop 

sand, debris 

6,000 bbls 3,000 

bbls/well 

Transport 

to shore in 

cuttings 

boxes, 

drums, 

and/or 

vessel tanks 

for pick up 

Sent to Port Fourchon, 

LA and on to Newpark 

Fourchon Transfer 

Station #1 & #2. 

Newpark Transfer 

Station Morgan City. 

Newpark Transfer 

Station Port Arthur. 

USLL Galveston and 

Fourchon Transfer 

Station 

Unused brine 

can be returned 

to vendor and/or 

stored for use 

on another job. 

Used brine and 

spent acid is 

transferred to 

Newpark's 

Processing & 

Transfer facility 

for injection. 

Workover 

fluids 

Brine, spent 

acid, prop 

sand, debris 

6,000 bbls 3,000 

bbls/well 

Transport 

to shore in 

cuttings 

boxes, 

drums, 

and/or 

vessel tanks 

Sent to Port Fourchon, 

LA and on to Newpark 

Fourchon Transfer 

Station #1 & #2. 

Newpark Transfer 

Station Morgan City. 

Newpark Transfer 

Unused brine 

can be returned 

to vendor and/or 

stored for use 

on another job. 

Used brine and 

spent acid is 
 

for pick up Station Port Arthur. 

USLL Galveston and 

Fourchon Transfer 

Station 

transferred to 

Newpark's 

Processing & 

Transfer facility 

for injection. 

Trash and 

debris 

Refuse 

generated 

during 

operations 

250 bbls 50 

bbls/month 

Transport 

to shore in 

disposal 

bags by 

vessel to 

shorebase 

for pickup 

by 

municipal 

operations 

Recycled Material in 

ARC, New Iberia, LA. 

Trash disposed of at 

SWDI landfill. 

Recycled and/or 

disposed in 

landfill. 

Used oil Excess oil from 

engines 

538 bbls 430 

bbls/120 

days 

Transport 

in totes to 

shore for 

pick up 

American Recovery 

Fourchon, LA 

Recycled 

*Total projected amount assumes 2 wells at 75 days/well 
 

M 

COASTAL ZONE MANAGEMENT ACT INFORMATION 
 

Texas 

The following is an evaluation that includes findings relating the coastal effects of the 

proposed activities and associated facilities to the relevant enforceable policies of the 

Texas’ Coastal Management Program (TCMP), Title 31, Part 16, Chapter 501, 

Subchapter B:

(Category 2) 

Construction, Operation & Maintenance of Oil & Gas Exploration & Production 

Facilities 

No operations are proposed in or near any critical areas. The proposed activities are 

explorative in nature, so no facility construction is proposed. The proposed activities are 

located approximately 413 miles from the Texas shoreline; therefore we expect no 

adverse impacts to CNRAs or beach access and use rights of the public. All activities 

shall be conducted in a manner that minimizes significant impacts to coastal resources. 

No adverse effects to Texas’ coastal area are expected in association with the proposed 

activities. 

(Category 3) 

Discharges of Wastewater and Disposal of Waste from Oil and Gas Exploration and 

Production Activities 

No discharge of wastewater or disposal of waste from the proposed activities will occur 

in the Texas’ coastal zone; therefore no impact to Texas’ coastal waters is expected. 

(Category 4) 

Construction and Operation of Solid Waste Treatment, Storage, and Disposal 

Facilities 

No construction of solid waste facilities or expansion of existing facilities in the coastal 

zone are proposed in the attached plan, therefore, no adverse effects on any features of 

Texas’ coastal cone are expected. 

(Category 5) 

Prevention, Response, and Remediation of Oil Spills 

The proposed activities will be covered under the Sub-Regional Oil Spill Response Plan. 

The plan is in place, practiced, and updated as necessary. The best practical techniques 

shall be utilized to prevent the release of pollutants or toxic substances into the 

environment. All involved vessels and facilities are designed to be capable of prompt 

response and adequate removal of accidental discharges of oil. In addition, the proposed 

activities are 413 miles from shore; therefore no damages to natural resources are 

expected as the result of an unauthorized discharge of oil into coastal waters. 
 

(Category 6) 

Discharge of Municipal and Industrial Waste Water to Coastal Waters 

No discharges from the proposed activities will occur in coastal waters. The proposed 

activities are 413 miles from shore; therefore there will be no effect on coastal waters. 

(Category 8) 

Development in Critical Areas 

None of the proposed activities will occur in a critical area; therefore no effects to Texas’ 

coastal zone are expected. The activity will not jeopardize the continued existence of 

species listed as endangered or threatened, and will not result in likelihood of the 

destruction or adverse modification of a habitat determined to be a critical habitat under 

the Endangered Species Act. The activity will not cause or contribute to violation of any 

applicable surface water quality standards. The activity will not violate any requirement 

imposed to protect a marine sanctuary. 

(Category 9) 

Construction of Waterfront Facilities and Other Structures on Submerged lands 

No waterfront facilities or other structures are proposed on submerged lands in the Texas 

coastal zone, therefore the proposed activities are not expected to have any adverse 

impacts on submerged lands. 

(Category 10) 

Dredging and Dredged Material Disposal and Placement 

No dredging or disposal/placement of dredged material is proposed; therefore no adverse 

effects to coastal waters, submerged lands, critical areas, coastal shore areas, or Gulf 

beaches are expected. 

(Category 11) 

Construction in the Beach / Dune System 

The proposed activities do not include any construction projects in critical dune areas or 

areas adjacent to or on Gulf beaches, therefore, no impact to Texas’ beach or dune 

systems are expected. 

(Category 15) 

Alteration of Coastal Historic Areas 

The proposed activities do not include any alteration or disturbance of a coastal historic 

area; therefore, no impacts are expected to adversely affect any historical, architectural, 

or archaeological site in Texas’ coastal zone. 
 

(Category 16) 

Transportation 

The proposed activities do not include any transportation construction projects within the 

coastal zone; therefore, no impacts to Texas’ coastal zone are expected. 

(Category 17) 

Emission of Air Pollutants 

The proposed activities shall be carried out in conformance with applicable air quality 

laws, standards, and regulations. Emissions from the proposed activities are not expected 

to have significant impacts on onshore air quality because of the prevailing atmospheric 

conditions, emission heights, emission rates, and the distance of these emissions from the 

coastline. The proposed activities will occur approximately 413 miles from shore and will 

be within the exemption limits set by BOEM, therefore, no impacts to Texas’ coastal 

zone is expected. 

(Category 18) 

Appropriations of Water 

The proposed activities do not include the impoundment or diversion of state water, 

therefore, no impacts to Texas’ coastal zone is expected. 

(Category 20) 

Marine Fishery Management 

The proposed activities are located approximately 413 miles from shore and are not 

expected to have any effect on marine fishery management or fishery migratory patterns 

within waters in the coastal zone of Texas. 

(Category 22) 

Administrative Policies 

The necessary information for applicable agencies to make an informed decision on the 

proposed activities has been provided In conclusion, all activities shall be consistent with 

Texas’ coastal management program and shall comply with all relevant rules and 

regulations. No activities are planned within any critical areas. Activities will be carried 

out avoiding unnecessary conflicts with other uses of the vicinity. 

 

Issues identified in the Louisiana Coastal Zone Management Program include the 

following: general coastal use guidelines, levees, linear facilities (pipelines); dredged soil 

deposition; shoreline modifications, surface alterations, hydrologic and sediment 

transport modifications, waste disposal; uses that result in the alteration of waters 

draining into coastal waters; oil, gas, or other mineral activities; and air and water quality. 

Relevant enforceable policies were considered in certifying consistency for Louisiana. 

 

MISSISSIPPI COASTAL ZONE MANAGEMENT ACT INFORMATION 

As authorized by the Federal Coastal Zone Management Act (CZMA), The State of 

Mississippi developed a Coastal Management Program (CMP) to allow for the review of 

proposed Federal license and permit activities affecting any coastal use or resources, in or 

outside of the Mississippi Coastal Zone. 

The OCS related oil and gas exploratory and development activities having potential 

impact on the Mississippi Coastal Zone are based on the location of the proposed 

facilities, access to those sites, best practical techniques for drilling locations, drilling 

equipment guidelines for the prevention of adverse environmental effects, effective 

environmental protection, emergency plans and contingency plans. 

Below are goals identified by the State of Mississippi and our comments and/or 

corresponding cross references: 

Goal 1: To provide for reasonable industrial expansion in the coastal area and to 

ensure the efficient utilization of waterfront industrial sites so that suitable sites are 

conserved for water dependent industry. 

The activities proposed in this plan are based out of Fourchon, Louisiana. The activities 

will not provide any industrial expansion on the coastal area of Mississippi. Therefore 

Mississippi coastal areas will be conserved for water dependent industry. 

Goal 2: To favor the preservation of the coastal wetlands and ecosystems, except 

where a specific alteration of specific coastal wetlands would serve a higher public 

interest in compliance with the public purposes of the public trust in which the 

coastal wetlands are held. 

Goal 2 is addressed in Section N–Environmental Impact Analysis. The nearest 

proposed activities will be 210 miles from the Mississippi coast. 

Goal 3: To protect, propagate and conserve the state’s seafood and aquatic life in 

connection with the revitalization of the seafood industry of the State of Mississippi. 

Goal 3 is addressed in Section N–Environmental Impact Analysis. Little impact to the 

seafood industry can be expected due to the activities occurring 210 miles from the 

Mississippi coast. 

Goal 4: To conserve the air and waters of the state, and to protect, maintain and 

improve the quality thereof for public use, for the propagation of wildlife, fish and 

aquatic life, and for domestic, agricultural, industrial, recreational and other 

legitimate beneficial uses. 

Goal 4 is addressed in Section B–General Information, Section G–Air Emissions 

Information, and Section N–Environmental Impact Analysis. 
 

Goal 5: To put to beneficial use to the fullest extent of which they are capable the 

water resources of the state, and to prevent the waste, unreasonable use, or 

unreasonable method of use of water. 

The activities proposed in this plan are based in Fourchon, Louisiana. As such, 

Mississippi’s water resources should not be impacted by the proposed activities. 

Activities occurring at the sites in the OCS will be conducted in accordance with our 

Sub-Regional Oil Spill Response Plan referenced in Section H of this plan. 

Goal 6: To preserve the state’s historical and archaeological resources, to prevent 

their destruction, and to enhance these resources wherever possible. 

Goal 6 is addressed in Section E–Biological, Physical and Socioeconomic Information,

and Section N–Environmental Impact Analysis. 

Goal 7: To encourage the preservation of natural scenic qualities in the coastal area. 

Goal 7 is addressed in Section F–Waste Discharges Information, Section H–Oil Spill 

Information, Section G–Air Emissions Information, and Section N–Environmental 

Impact Analysis. 

Goal 8: To assist local governments in the provision of public facilities services in a 

manner consistent with the coastal program. 

As the proposed activities are located 210 miles from the Mississippi coast and are based 

out of a shorebase in Fourchon, Louisiana, local governments should not be affected. 

 

ALABAMA COASTAL ZONE MANAGEMENT 

CONSISTENCY CERTIFICATION 

EP – LLOYD RIDGE BLOCK 621 

The OCS related oil and gas development activities having potential impact on the 

Alabama Coastal Zone are based on the location of the proposed facilities, access to those 

sites, best practical techniques for operations and production equipment, guidelines for 

the prevention of adverse environmental effects, effective environmental protection, 

emergency plans and contingency plans. Alabama policies have been addressed below or 

are cross referenced to the appropriate sections of the plan: 

Topic Cross 

Reference 

Comments 

Coastal 

Resource Use 

Policies 

 

Coastal 

Development 

 Dock and port facilities in LA will be used. There will be no new construction, 

dredging, or filling in Alabama state waters. There will be no new commercial 

development or capital improvements in Alabama’s coastal zone, nor will there 

be any employment effects. 

Mineral Resource 

Exploration and 

Extraction 

 Proposed exploration operations will take place 203 miles from Alabama’s 

coastline. 

Commercial 

Fishing 

Section N 

Hazard 

Management 

Section C A Shallow Hazards Report and Addendums to Site Clearance Letters for 

Proposed Wellsites A and B has been prepared and submitted to BOEM in order 

to identify and assess the seafloor and shallow geologic conditions in this 

block(s). 

Shoreline 

Erosion 

Section N Proposed exploration operations will take place 203 miles from Alabama’s 

coastline. 

Recreation Section N 

Transportation Section K, L, N 

Natural 

Resource 

Protection 

Policies 

 

Biological 

Productivity 

Section N

Water Quality Section N

Water Resources Section N

Air Quality Section N

Wetlands and 

Submerged 

Grassbeds 

Section N

Beach and Dune 

Protection 

Section N

Wildlife Habitat 

Protection 

Section N

Endangered 

Species 

Section N

Cultural 

Resources 

Protection 

Section N This block does not lie within a high probability zone for historic shipwrecks, 

and thus does not require an archaeological report. As part of the Hazards Report, 

it was determined that no man-made facilities nor seafloor obstructions were 

located in the survey area. 

 

COASTAL ZONE MANAGEMENT ACT INFORMATION 

CONSISTENCY CERTIFICATION 

ANADARKO PETROLEUM CORPORATION’S CERTIFICATION OF 

CONSISTENCY 

WITH THE STATE OF FLORIDA COASTAL MANAGEMENT PROGRAM 

Introduction 

This Consistency Certification is an evaluation by Anadarko Petroleum Corporation 

(Anadarko) of its proposed Initial Exploration Plan (EP) in Lloyd Ridge Block 621 for 

any reasonably foreseeable coastal effects on the land, water uses, or natural resources, of 

the coastal zone of Florida, pursuant to the enforceable policies of the Florida Coastal 

Management Program (FCMP). The Initial EP is supported by numerous studies 

performed by government agencies and the oil and gas industry concerning impacts of oil 

and gas activities in the Gulf of Mexico and other offshore areas around the world. For 

citations to these studies and agencies, please see the Environmental Impact Analysis 

(EIA). 

The Initial EP provides for the subsea drilling and completion of three wells. The 

activities in Lloyd Ridge Block 621 will occur in outer continental shelf (OCS) waters, 

offshore Alabama, approximately 205 miles from the nearest Florida shoreline. 

Anadarko believes that the planned activities will have little, if any, effect beyond the 

area immediately adjacent to the proposed activity sites, and that the possibility of any 

impacts to Florida’s coastal zone is remote. However, Anadarko has undertaken this 

consistency evaluation and believes that the proposed activities comply with the 

enforceable policies of the FCMP and will be conducted in a manner consistent with this 

Program. 

The activities will be conducted in accordance with the Bureau of Ocean Energy 

Management (BOEM), the Bureau of Safety and Environmental Enforcement (BSEE), 

and U.S. Environmental Protection Agency (USEPA) regulations, applicable Notices to 

Lessees (NTLs), conditions in the approved permits, and lease stipulations. All required 

Federal permits will be obtained, and all activities will be conducted in compliance with 

such regulations, NTLs, conditions, and stipulations. 

Consistency Analysis 

The FCMP is authorized by the Florida Coastal Management Act, Chapter 380, Land and 

Water Management, Part II, Coastal Planning and Management, of the Florida Statutes. 

For this consistency certification, Anadarko has analyzed the proposed action in relation 

to 16 chapters of the Florida Statutes identified by the State as “core enforceable policies” 

having specific applicability to offshore oil and gas activity: 

(1) Chapter 161 – Beach and Shore Preservation 

(2) Chapter 252 – Emergency Management 

(3) Chapter 253 – State Lands 

(4) Chapter 258 – State Parks and Preserves 
 

(5) Chapter 259 – Land Acquisitions for Conservation or Recreation 

(6) Chapter 260 – Recreational Trails System 

(7) Chapter 267 – Archives, History, and Records Management 

(8) Chapter 288 – Commercial Development and Capital Improvements 

(9) Chapter 370 – Saltwater Fisheries 

(10) Chapter 372 – Wildlife 

(11) Chapter 373 – Water Resources 

(12) Chapter 375 – Outdoor Recreation and Conservation 

(13) Chapter 376 – Pollution Discharge Prevention and Removal 

(14) Chapter 377 – Energy Resources 

(15) Chapter 403 – Environmental Control 

(16) Chapter 582 – Soil and Water Conservation 

1. Chapter 161 – Beach and Shore Preservation 

The enforceable policies in this chapter recognize that coastal areas are among the State’s 

most valuable natural, aesthetic, and economic resources and that they protect and 

provide habitat for a variety of plant and animal life. The State is required to protect 

beach and dune systems from imprudent activities that could weaken, damage, or destroy 

the integrity of the system, manage coastal sediments to reduce erosion, and restore and 

maintain critically eroding beaches. The State also designates coastal areas used, or 

likely to be used, by sea turtles for nesting and prohibits the removal of vegetative cover 

that binds sand. This chapter includes Part I, Regulation of Construction, Reconstruction, 

and Other Physical Activity; Part II, Beach and Shore Preservation Districts; and Part III, 

Coastal Zone Protection. 

As Anadarko will be using existing heliports, dock and port facilities in Fourchon, 

Louisiana during the proposed activities, there will be no new construction, dredging, or 

filling on Florida’s lands or waters that could weaken, damage, or destroy the integrity of 

the system or cause erosion of beaches. In addition, oil spill impacts on Florida beaches 

and other coastal areas are highly unlikely due to the distance from shore and the 

measures detailed in Anadarko’s Sub-Regional Oil Spill Response Plan (OSRP), which 

addresses procedures for containment, recovery, and removal of an oil spill. The 

precautions included in Anadarko’s plan are consistent with the core policies of 

protecting beach and dune systems. Therefore, the proposed activities are consistent with 

Chapter 161. 

2. Chapter 252 – Emergency Management 

The enforceable policies of this chapter direct the State to reduce the vulnerability of its 

people and property to natural and manmade disasters; prepare for, respond to, and 

reduce the impacts of natural and manmade disasters; and decrease the time and 

resources needed to recover from disasters. Disaster mitigation is necessary to ensure the 

common defense of Floridians’ lives and to protect the public peace, health, and safety. 

The policies provide the means to assist in the prevention or mitigation of emergencies 

that may be caused or aggravated by the inadequate planning or regulation of facilities 

and land uses. State agencies are directed to keep land uses and facility construction 

under continuing study and identify areas that are particularly susceptible to natural or 

manmade catastrophic occurrences. 
 

The proposed activities do not involve construction or operation of any facilities in the 

State of Florida. Therefore, a large oil spill is the only emergency that is considered 

relevant to this analysis. Anadarko has developed a Sub-Regional OSRP that outlines 

response actions, inspection and maintenance of response equipment, required spill 

response drills, governmental notification procedures, inventories of response equipment, 

response team organization, spill movement monitoring, and contingency plans for oil 

spill containment, recovery, and removal. An oil spill is highly unlikely to reach Florida 

waters or shorelines due to the distance from shore and the measures detailed in 

Anadarko’s Sub-Regional OSRP, which addresses procedures for containment, recovery, 

and removal of an oil spill. The precautions included in Anadarko’s plan are consistent 

with the core policies of preparing for and responding to an oil spill and reducing the 

vulnerability of Florida’s people and resources to impacts if such a spill occurred. 

Therefore, the proposed activities are consistent with Chapter 252. 

3. Chapter 253 – State Lands 

This chapter, in part, defines State-owned and State-managed lands and grants authority 

to acquire and lease lands and to grant rights-of-way and easements. The enforceable 

policies guide the management of State-owned and sovereign submerged lands and 

property by the Board of Trustees of the Internal Improvement Trust Fund (Trustees). 

Lands acquired for preservation, conservation, and recreation serve the public interest by 

contributing to the public health, welfare, and economy. In carrying out the requirements 

of this statute, the Trustees are directed to take necessary action to fully conserve and 

protect State lands, maintain natural conditions, protect and enhance natural areas and 

ecosystems, prevent damage and depredation, and preserve archaeological and historical 

resources. All submerged lands are considered single-use lands to be maintained in 

natural condition for the propagation of fish and wildlife and public recreation. Where 

multiple-uses are permitted, ecosystem integrity, recreational benefits, and wildlife values 

are conserved and protected. 

During operations in the lease area, Anadarko will not seek to lease or acquire rights-ofway across Florida State lands. Anadarko will be using existing heliports, dock and port 

facilities in Fourchon, Louisiana during the proposed activities. There will be no 

activities requiring acquisition of rights-of-way or easements on Florida State lands. In 

addition, oil spill impacts on State owned and managed lands are highly unlikely due to 

the distance from shore and the measures detailed in Anadarko’s Sub-Regional Oil Spill 

Response Plan (OSRP), which addresses procedures for containment, recovery, and 

removal of an oil spill. The precautions in Anadarko’s plan are consistent with the core 

policies to fully conserve and protect State lands and other natural areas and ecosystems. 

Therefore, the proposed activities are consistent with Chapter 253. 

4. Chapter 258 – State Parks and Preserves 

State parks, aquatic preserves, and recreation areas are acquired to exemplify the State’s 

natural values and to ensure that these values are conserved for all time. Parks and 

preserves are managed for the non-depleting use, enjoyment, and benefit of Floridians 

and visitors and to contribute to the State’s tourist appeal. Aquatic preserves are 

recognized as having exceptional biological, aesthetic, and scientific value and are set 
 

aside for the benefit of future generations. Disruptive physical activities and polluting 

discharges are highly restricted in aquatic preserves. State managed wild and scenic 

rivers possess exceptionally remarkable and unique ecological, fish and wildlife, and 

recreational values and are designated for permanent preservation and enhancement for 

both the present and future. 

Chapter 258 specifies limitations on dredge-and-fill activities, discharges, erection of 

structures, and drilling for oil or gas within aquatic preserves. Anadarko’s proposed 

activities in the lease area are not within or adjacent to any State parks or aquatic 

preserves. All discharges for the proposed activity will be governed by the National 

Pollutant Discharge Elimination System (NPDES) General Permit or an Individual 

Permit; impacts will be localized in deep, offshore waters, and will not have any effect on 

State parks, aquatic preserves, and recreation areas. Finally, oil spill impacts in these 

coastal areas are highly unlikely due to the distance from shore and the measures detailed 

in Anadarko’s Sub-Regional OSRP, which addresses procedures for containment, 

recovery, and removal of an oil spill. The precautions in Anadarko’s plan are consistent 

with the core policies of preserving and protecting the natural resources and aesthetic 

values of Florida’s State parks, aquatic preserves, and recreation areas. Therefore, the 

proposed activities are consistent with Chapter 258. 

5. Chapter 259 – Land Acquisitions for Conservation or Recreation 

This chapter discusses the “Land Conservation Act” and the acquisition of lands or water 

areas for preservation, conservation, and recreational purposes. The chapter indicates an 

area is of special importance to the State if it involves an endangered or natural resource 

in imminent danger of development, is of unique value to the State, will result in 

irreparable loss to the State, or will impair the State’s ability to manage or protect other 

State-owned lands. The enforceable policies guide the acquisition and management of 

lands to conserve and maintain the State’s unique natural resources, protect 

environmental quality, and provide recreation opportunities for the benefit of future 

generations. Florida’s legislature and citizens have made a tremendous financial 

commitment to long-term land acquisitions that will preserve and restore unique 

ecosystems, habitats, water resources, and recreational lands. 

Anadarko will be using existing heliports, dock and port facilities in Fourchon, Louisiana 

during the proposed activities. Therefore, there will be no new development, 

construction, dredging, or filling on Florida’s lands or waters. In addition, all discharges 

for the proposed activity will be governed by the NPDES General Permit or an Individual 

Permit; impacts will be localized in deep, offshore waters and will not have any effect on 

Florida lands being acquired or managed for preservation, conservation, or recreational 

purposes. Finally, oil spill impacts in these coastal areas are highly unlikely due to the 

distance from shore and the measures detailed in Anadarko’s Sub-Regional OSRP, which 

addresses procedures for containment, recovery, and removal of an oil spill. The 

precautions in Anadarko’s plan are consistent with the core policies of managing lands to 

conserve and maintain the State’s unique natural resources, protect environmental 

quality, and provide recreation opportunities. Therefore, the proposed activities are 

consistent with Chapter 259. 
 

6. Chapter 260 – Recreational Trails System 

This chapter discusses the “Florida Greenways and Trails Act” and the State policies to 

conserve, develop, and use its natural resources for healthful and recreational purposes by 

the establishment of a “Florida Greenways and Trails System.” The System serves to 

provide recreational opportunities, including, among others, canoeing, jogging, and 

historical and archaeological interpretation, by acquiring designated lands and waterways 

for open space to benefit environmentally sensitive lands and wildlife. 

As Anadarko will be using existing heliports, dock and port facilities in Fourchon, 

Louisiana during the proposed activities, there will be no new construction, dredging, or 

filling on Florida’s lands or waters, and no motorized watercraft will conduct any 

operations within or adjacent to any defined canoe trail necessary to ensure the safe use 

of a water body for canoes. Therefore, the proposed activities are consistent with the 

core policies of Chapter 260. 

7. Chapter 267 – Archives, History, and Records Management 

This chapter discusses the “Florida Historical Resources Act,” the State policy to locate, 

inventory, and evaluate historic properties, and the preservation by the Division of 

Historical Resources of the Department of State, of all historical property, including 

sunken or abandoned ships with intrinsic historical or archaeological value. The 

enforceable policies recognize the State’s rich and unique heritage of historic resources 

and direct the State to locate, acquire, protect, preserve, operate, and interpret historic and 

archaeological resources for the benefit of current and future generations of Floridians. 

Objects or artifacts with intrinsic historic or archaeological value located on, or 

abandoned on, State-owned lands or State-owned submerged lands belong to the citizens 

of the State. The Act operates in conjunction with the National Historic Preservation Act 

of 1966 to require State and Federal agencies to consider the effect of their direct or 

indirect actions on historic and archaeological resources. These resources cannot be 

destroyed or altered unless no prudent alternative exists. Unavoidable impacts must be 

mitigated. 

Lloyd Ridge Block 621 is not on the BOEM/BSEE list of blocks determined to have a 

high probability of either prehistoric or historical archaeological resources. A shallow 

hazards report covering portions of this block, including the proposed wellsite locations, 

is being submitted with this Initial Exploration Plan and did not detect any shipwrecks in 

the survey area. It is highly unlikely that objects or artifacts with intrinsic historic or 

archaeological value would be affected by Anadarko’s activities. Therefore, the 

proposed activities are consistent with the core policies of Chapter 267. 

8. Chapter 288 – Commercial Development and Capital Improvements 

Chapter 288 establishes enforceable policies that promote and develop the general 

business, trade, and tourism components of the State economy. The policies include 

requirements to protect and promote the natural, coastal, historical, and cultural tourism 

assets of the State, foster the development of nature-based tourism and recreation, and 

upgrade the image of Florida as a quality destination. Natural resource-based tourism 

and recreational activities are critical sectors of Florida’s economy. The needs of the 

environment must be balanced with the need for growth and economic development. 
 

As Anadarko will be using existing heliports, dock and port facilities in Fourchon, 

Louisiana during the proposed activities, there will be no activities conducted in Florida 

that would affect the general business, trade, or tourism components of the State 

economy. 

There will be no project associated vessel or aircraft traffic in Florida waters, and there 

are no plans to purchase supplies or equipment in Florida. The project area is at least 205 

miles from the nearest Florida shoreline, and activities will not be visible from the coast 

or Florida State waters. As discussed in the EIA, water quality impacts of routine 

discharges will be localized in the vicinity of the drillsites and will not affect Florida 

lands or waters. Disposal of trash and debris into the ocean is strictly prohibited, and 

waste management practices required under BSEE NTL 2012-G01 will minimize the 

chance of trash or debris being lost overboard and subsequently washing up on beaches. 

Oil spill impacts in Florida coastal areas are highly unlikely due to the distance from 

shore and the measures detailed in Anadarko’s Sub-Regional OSRP, which addresses 

procedures for containment, recovery, and removal of an oil spill. The precautions in 

Anadarko’s plan are consistent with the core policies of protecting the natural, coastal, 

historical, and cultural tourism assets of the State and maintaining the image of Florida as 

a quality destination. Therefore, the proposed activities are consistent with Chapter 288. 

9. Chapter 370 – Saltwater Fisheries 

The enforceable policies of this chapter direct the State to conserve and manage its 

renewable marine fishery resources through the protection and management of marine 

habitat and saltwater fisheries. The paramount conservation and management objective is 

the continuing health and abundance of the resource. Best available information must be 

used to manage and protect the State’s marine, crustacean, shellfish, and finfish resources 

and to regulate the commercial and recreational use of the State’s saltwater fisheries to 

ensure optimum sustained benefits to the people of the State. 

As discussed in the EIA, effluents from project activities may temporarily affect water 

quality in the immediate vicinity of the wellsites in the lease area. Discharges including 

well completion fluids, sanitary and domestic waste, deck drainage, uncontaminated 

seawater for cooling machinery, and desalination brine may cause localized, short-term 

impacts on water quality near the site. All discharges will be in compliance with the 

standards imposed by the NPDES General Permit or an Individual Permit. Water quality 

is expected to quickly return to normal in the area after operations have been completed. 

Due to the low toxicity and rapid dispersion of discharges, little or no impact on water 

column biota is likely, including fish larvae that recruit to nearshore nursery areas. 

There is a very low probability that a spill may occur during operations. The potential 

impacts of these types of spills on Florida’s coastal zone are discussed in the EIA. 

Anadarko’s Sub-Regional OSRP outlines response actions for hypothetical spill events. 

The Sub-Regional OSRP makes provisions for the use of a dispersant by boat or aerial 

application but notes that before a dispersant can be applied; Federal and State authorities 

must grant permission. Additional items that are addressed in the plan include provisions 

for inspection and maintenance of response equipment; required spill response drills; 
 

procedures for spill notification to government agencies; inventories of locally and 

nationally available response equipment; hierarchy of response team organization; 

provisions for disposal of wastes; and procedures for monitoring and predicting spill 

movement. 

Finally, Anadarko will be using a dynamically positioned (DP) drillship or DP semisubmersible drilling rig in its proposed activities, with state-of-the-art equipment and 

technology for spill prevention, and will be operating in compliance with the NPDES 

General Permit or an Individual Permit regarding authorized discharges. If an oil spill 

should occur, Anadarko’s Sub-Regional OSRP addresses plans and procedures for basic 

spill containment, recovery, and removal. Anadarko is also a member of the Helix Well 

Containment Group (HWCG) and Marine Well Containment Company (MWCC). As a 

member, Anadarko has access to subsea well containment and well shut-in equipment. 

The precautions in Anadarko’s plan are consistent with the core policies of conserving 

and protecting marine habitat and saltwater fisheries and maintaining the continuing 

health and abundance of the resource. Therefore, Anadarko’s proposed activities are 

consistent with Chapter 370. 

10. Chapter 372 – Wildlife 

This chapter discusses the “Florida Endangered and Threatened Species Act” and its 

implementation by the Fish and Wildlife Conservation Commission to conserve and 

protect the fish and wildlife resources of the State, particularly those species defined as 

endangered or threatened. The Fish and Wildlife Conservation Commission has 

established a Wildlife Habitat Program, and a Conservation and Recreation Lands 

Program Trust Fund, for acquiring and managing lands for the conservation of fish and 

wildlife. The enforceable policies direct the State to conserve its diverse fish and wildlife 

resources. Florida has more endangered or threatened species than any other continental 

state; therefore, the protection of species defined as endangered or threatened is 

emphasized. State lands that provide habitat needed by these species shall be maintained 

and enhanced for their value as fish and wildlife habitat. Substances thrown, spilled, 

drained, or discharged into fresh waters that injure or kill fish are expressly prohibited. 

As Anadarko will be using existing heliports, dock and port facilities in Fourchon, 

Louisiana during the proposed activities, there will be no new construction, dredging, or 

filling on Florida’s lands or waters to affect wildlife habitats or recreation lands. As 

discussed in the EIA, routine discharges will be localized in the vicinity of the drillsites 

and will not have any effects on Florida lands, waters, or wildlife. Disposal of trash and 

debris into the ocean is strictly prohibited, and waste management practices required 

under BSEE NTL 2012-G01 will minimize the chance of trash or debris being lost 

overboard and subsequently endangering Florida wildlife. Oil spill impacts in Florida 

coastal areas are highly unlikely due to the distance from shore and the measures detailed 

in Anadarko’s Sub-Regional OSRP, which addresses procedures for containment, 

recovery, and removal of an oil spill. The precautions in Anadarko’s plan are consistent 

with the core policies of conserving Florida’s fish and wildlife resources, including 

endangered or threatened species. Therefore, the proposed activities are consistent with 

Chapter 372. 
 

11. Chapter 373 – Water Resources 

This chapter establishes enforceable policies that guide the management and protection of 

water resources, water quality, and environmental quality. The policies address the 

conservation of surface and ground waters for full beneficial use; sustainable water 

management; preservation of natural resources, fish, and wildlife; protecting public land; 

and promoting the health and general welfare of Floridians. The State manages and 

conserves water and related natural resources by determining whether activities will 

unreasonably consume water, degrade water quality, or adversely affect environmental 

values such as protected species habitat, recreational pursuits, and marine productivity. 

As Anadarko will be using existing heliports, dock and port facilities in Fourchon, 

Louisiana during the proposed activities, there will be no usage of Florida water 

resources and no new construction, dredging, or filling on Florida’s lands or waters to 

affect water quality, protected habitat, recreational pursuits, or marine productivity. All 

discharges for the proposed activity will be governed by the NPDES General Permit or an 

Individual Permit; impacts will be localized in deep, offshore waters and will not pollute 

Florida land or waters. In addition, oil spill impacts on Florida water resources are highly 

unlikely due to the distance from shore and the measures detailed in Anadarko’s SubRegional OSRP, which addresses procedures for containment, recovery, and removal of 

an oil spill. The precautions in Anadarko’s plan are consistent with the core policies of 

conserving surface and ground waters for full beneficial use and protecting natural 

resources, fish, wildlife, and public lands. Therefore, the proposed activities are 

consistent with Chapter 373. 

12. Chapter 375 – Outdoor Recreation and Conservation 

This chapter discusses the “Outdoor Recreation and Conservation Act of 1963” and the 

responsibility of the Florida Department of Environmental Protection (FDEP) to 

implement a comprehensive outdoor recreation plan in cooperation with the Fish and 

Wildlife Conservation Commission and the water management districts. The FDEP 

participates in the land and water conservation fund program to acquire lands and water 

areas for outdoor recreation, natural resource conservation, wildlife and forestry 

management, and water conservation and control. The Act also empowers the Fish and 

Wildlife Conservation Commission to regulate motor vehicle access and traffic control 

on public lands. 

Anadarko will be using existing heliports, dock and port facilities in Fourchon, Louisiana 

during the proposed activities. Therefore, there will be no new construction, dredging, or 

filling on Florida’s lands or waters, and no new vehicle traffic on public lands. In 

addition, oil spill impacts on Florida conservation, recreation, or resource areas are highly 

unlikely due to the distance from shore and the measures detailed in Anadarko’s SubRegional OSRP, which addresses procedures for containment, recovery, and removal of 

an oil spill. The precautions in Anadarko’s plan are consistent with the core policies of 

preserving Florida’s lands and water areas for outdoor recreation, conservation, and 

wildlife management. Therefore, the proposed activities are consistent with Chapter 375. 
 

13. Chapter 376 – Pollution Discharge Prevention and Removal 

Chapter 376 declares that the preservation of the seacoast as a source of public and 

private recreation and the preservation of water and certain lands are matters of the 

highest urgency and priority and shall be accomplished by maintaining surface and 

ground water, coastal waters, estuaries, tidal flats, beaches, and public lands adjoining the 

seacoast in as close to a pristine condition as possible. The discharge of pollutants into or 

upon any coastal waters, estuaries, tidal flats, beaches, and lands adjoining the seacoast of 

the State is declared to be inimical to the paramount interests of the State and is 

prohibited. The statute provides for hazards and threats of danger and damages resulting 

from any pollutant discharge to be evaluated, requires the prompt containment and 

removal of pollution, provides penalties for violations, and ensures the prompt payment 

of reasonable damages from a discharge. Portions of Chapter 376 serve as a complement 

to the national contingency plan portions of the Federal Water Pollution Control Act. 

Anadarko has prepared a Sub-Regional OSRP as required for the Eastern Planning Area, 

which must be consistent with the National Contingency Plan and with the Oil Pollution 

Act of 1990 (OPA) in order to obtain BSEE approval. As Anadarko will be using the 

existing dock and port facilities in the Fourchon, Louisiana area, there will be no transfers 

between vessels and Florida onshore facilities. As to transfers between offshore facilities 

and vessels, Anadarko’s Sub-Regional OSRP outlines response actions, inspection and 

maintenance of response equipment, required spill response drills, governmental 

notification procedures, inventories of response equipment, response team organization, 

spill movement monitoring, and contingency plans for oil spill containment, recovery, 

and removal. The precautions in Anadarko’s plan are consistent with the core policies of 

preventing unauthorized pollutant discharges and maintaining surface and ground water, 

coastal waters, estuaries, tidal flats, beaches, and public lands in as close to a pristine 

condition as possible. Therefore, the proposed activities are consistent with Chapter 376. 

14. Chapter 377 – Energy Resources 

The State’s policy is to conserve and control the oil and gas resources in the State, 

including products made from these resources, and to safeguard the health, property, and 

welfare of Floridians. To accomplish this, Chapter 377 addresses the regulation, 

planning, and development of the energy resources of the State. The FDEP is authorized 

to regulate all phases of exploration, drilling, and production of oil, gas, and other 

petroleum products in the State. This chapter describes the permitting requirements and 

criteria necessary to drill for and develop oil and gas. FDEP rules ensure that all 

precautions are taken to prevent the spillage of oil or any other pollutant in all phases of 

extraction and transportation. 

The State explicitly prohibits pollution resulting from drilling and production activities. 

No person drilling for or producing oil, gas, or other petroleum products may pollute land 

or water; damage aquatic or marine life, wildlife, birds, or public or private property; or 

allow any extraneous matter to enter or damage any mineral or freshwater-bearing 

formation. Penalties for violations of any provisions of this chapter are detailed. 

The proposed project does not involve any drilling or production activities in Florida that 

are regulated by the FDEP. All discharges will be in accordance with the NPDES 
 

General Permit or an Individual Permit; impacts will be localized in deep, offshore waters 

and will not pollute Florida land or waters, damage wildlife or public or private property, 

or contaminate any mineral or freshwater bearing formation. Disposal of trash and debris 

into the ocean is strictly prohibited and waste management practices required under 

BSEE NTL 2012-G01 and Lease Stipulation No. 4 will minimize the chance of trash or 

debris being lost overboard and subsequently washing up on Florida shorelines or waters. 

Oil spill impacts in Florida coastal areas are highly unlikely due to the distance from 

shore and the measures detailed in Anadarko’s Sub-Regional OSRP, which addresses 

procedures for containment, recovery, and removal of an oil spill. The precautions in 

Anadarko’s plan are consistent with the core policies of safeguarding the health, property, 

and welfare of Floridians and preventing pollution during offshore activities. Therefore, 

the proposed activities are consistent with Chapter 377. 

15. Chapter 403 – Environmental Control 

Chapter 403 establishes enforceable policies that guide environmental control efforts by 

conserving State waters, protecting and improving water quality for consumption and for 

the propagation of fish and wildlife, and maintaining air quality to protect human health 

and plant and animal life. Statutory provisions are enacted to protect the health, peace, 

safety, and general welfare of the people of the State. The statute provides wide-ranging 

authority to address various environmental control concerns, including air and water 

pollution, resource recovery and management, solid and hazardous waste management, 

drinking water protection, pollution prevention, ecosystem management, and natural gas 

transmission pipeline siting. Chapter 403 declares that pollution of the air and waters is a 

menace to public health and is harmful to wildlife, fish, and other aquatic life and that the 

policy of the State is to conserve, maintain, and improve its waters and air quality and 

develop a comprehensive program for its prevention, abatement, and control of pollution 

by establishing ambient air and water quality standards. 

The Projected Air Quality Emissions Report (EP Section G) for the proposed activities 

falls well below allowable exemption levels and will not result in onshore ambient air 

concentrations above significant levels as prescribed in the regulations. Therefore, the 

proposed activities are consistent with the core policies of Chapter 403. 

All discharges (inclusive of well completion fluids, sanitary and domestic wastes, deck 

drainage, and miscellaneous wastes) shall be in compliance with the standards imposed 

by the USEPA Region IV NPDES General Permit or an Individual Permit. As discussed 

in the EIA, discharges from project activities may temporarily affect water quality in the 

immediate vicinity of the drillsites but would not affect water quality or wildlife in 

Florida State waters. Pollution of coastal waters by an oil spill is highly unlikely due to 

the distance from shore and the measures detailed in Anadarko’s Sub-Regional OSRP, 

which addresses procedures for containment, recovery, and removal of an oil spill. The 

precautions in Anadarko’s plan are consistent with the core policies of conserving State 

waters and protecting water and air quality. Therefore, the proposed activities are 

consistent with Chapter 403. 

 

possible, the approximate number of new employees and families likely to move into 

the affected area; 

 Not applicable to the proposed activity. 

(2) An estimate of the major supplies, services, energy, water, or other resources you 

expect to purchase within the State of Florida and that are necessary for you to carry 

out the activities in your EP; and 

 Not applicable to the proposed activity. 

(3) The types of contractors or vendors within the State of Florida you will need to 

carry out the activities in your EP. 

 Not applicable to the proposed activity. 

(c) A complete description of any dredging and filling activities associated with the 

construction or expansion of any onshore facilities in Florida you will use to support 

your proposed activities. 

 Not applicable to the proposed activity. There will be no construction or 

expansion of any onshore facilities in Florida. Therefore dredging or filling 

activities are not applicable. 

(d) The type and volume of chemical constituents of drilling muds anticipated to be used. 

 Information is provided in EP Section B, F, K and L. 

(e) Detailed information on the presence of threatened and endangered species in the 

project area.

 Information is provided in the following EIA sections: C.3.1-C.3.4 (Marine 

Mammals), C.3.5 (Sea Turtles), C.4.2 (Shore Birds and Coastal Nesting Birds), 

C.3.8 (Gulf Sturgeon), and C.3.9 (Endangered Beach Mice) and C.3 (Florida Salt 

Marsh Vole). Further information is provided in the Sale 208 EIS. 

(f) A discussion of air and water quality in and adjacent to the area of proposed activity 

or potential impact.

 Information is provided in the following EIA sections: C.1.1 (Air Quality) and 

C.1.2 (Water Quality). Further information is provided in the Sale 208 EIS. 

(g) A thorough description of coastal habitats (including bays, bayous, sounds, estuaries, 

lagoons, rivers, streams, or other bodies of water) and their associated flora and fauna 

that could be affected by the proposed activities. 

 Information is provided in the following EIA sections: C.7, Table 7 (Beaches), C.7 

(Wetlands), C.4.2 (Shore Birds and Coastal Nesting Birds), C.7 (Coastal Wildlife 

Refuges), and C.1.1, C.7 (Wilderness Areas). Further information is provided in 

the Sale 208 EIS and in the Sub-Regional OSRP. 

(h) A description of any historical and archaeological resources that could be affected by 

your proposed activities. Describe the measures you will use to protect these 
 

resources. Describe thoroughly the surveys you used to locate and identify these 

resources. 

 Information is provided in the following EIA sections: C.6.1 (Shipwreck Sites, 

known or potential) and C.6.2 (Prehistoric Archaeological Sites). Further 

information is provided in the Sale 208 EIS. 

(i) A discussion of sensitive or critical State and Federal resources, including specially 

designated and managed areas, that may be impacted by the project (planned 

activities or accidental discharges). 

 Information is provided in the following EIA sections: C.7, Table 7 (Coastal 

Wildlife Refuges), C.1.1, C.7, Table 7 (Wilderness Areas), and C.5.2, Figure 3 

(Offshore Areas of Concern). Further information is provided in the Sale 208 

EIS. 

(j) A description of the potential for and types of direct, indirect or secondary, and 

cumulative impacts of the project (planned project activities and accidents) on: air 

quality; water quality and quantity; marine and coastal habitats; flora and fauna 

(including threatened and endangered species); coastal littoral processes; publicly 

owned and managed lands; cultural or historic resources; recreational and commercial 

fisheries; communities; the state and local economy; navigation; marine productivity; 

and other uses of the area. 

 Information is provided in the EIA/EP sections listed below. Further information 

is provided in the Sale 208 EIS. 

- Air Quality: Section C.1.1; EP Section E 

- Water Quality: Section C.1.2; EP Section E 

- Marine and Coastal Habitats: Sections C.2, C.2.1-C.2.5, C.3, C.3.1-C.3.9, 

C.7; EP Section E 

- Flora and Fauna (including endangered/threatened species): Section C.2.1; 

EP Section E 

- Coastal Littoral Processes: Sections A.6, A.7; EP Section F, L 

- Publicly Owned and Managed Lands: Section C.8.5 (land use) 

- Cultural or Historic Resources: Sections C.6.1, C.6.2 

- Recreational and Commercial Fisheries: Sections C.8.1 

- Communities: Section C.2.1, C.2.2 

- State and Local Economy: Sections C.8.4 

- Navigation: Sections C.4.1, C.4.2 

- Marine Productivity: Sections C.5.1; EP Section M 

- Other Uses of the Area: Section C.8.6 
 

(k) A description of measures you will take to avoid, minimize, and mitigate impacts to 

marine and coastal environments and habitats, biota, and threatened and endangered 

species. 

 As noted in the EIA Section C and EP Section E and I, the proposed action 

includes all of the routine mitigation measures required by laws and regulations, 

including all applicable Federal, State, and local requirements concerning air 

emissions, discharges to water, and solid waste disposal, as well as any 

additional permit requirements. In addition, implementation of Anadarko’s SubRegional OSRP would potentially help mitigate and reduce potential impacts. All 

project activities will be conducted under the Sub-Regional OSRP. 

(l) Existing and planned monitoring that will measure environmental conditions, 

including but not limited to that required by lease stipulation. 

 Lloyd Ridge Block 621 is located within Deepwater Grid Area 21. This grid is 

considered to have “inadequate ROV survey coverage”, and, therefore, under the 

guidance set out in NTL No. 2008-G06, a Remotely Operated Vehicle Monitoring 

Survey Plan is required. 

 Pursuant to NTL 2008-G06, operators may be required to conduct remotely 

operated vehicle (ROV) surveys during the proposed operations for the purpose of 

biological and physical observations. 

 Anadarko is familiar with the ROV survey and reporting provisions of NTL 2008-

G06; and if required, will conduct a survey. Refer to EP Section G–Biological, 

physical, and Socioeconomic Information for additional information.
 

N

ENVIRONMENTAL IMPACT ANALYSIS 
Environmental Impact Analysis

INITIAL EXPLORATION PLAN

for

Lloyd Ridge Block 621 (OCS‐G 33323)

Offshore Alabama

October 2011

Prepared for:

Bridget O’Farrell

Regulatory Analyst

Anadarko Petroleum Corporation

1201 Lake Robbins Drive

The Woodlands, Texas  77380

Telephone: (832) 636‐1694

Prepared by:

CSA International, Inc.

8502 SW Kansas Avenue

Stuart, Florida  34997

Telephone: (772) 219‐3000
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page ii

Contents

Page

Introduction ................................................................................................................1

A.  Impact‐Producing Factors .......................................................................................5

A.1 Drilling Rig Presence (including noise and lights)........................................................................... 5

A.2 Physical Disturbance to the Seafloor.............................................................................................. 8

A.3 Air Pollutant Emissions................................................................................................................... 8

A.4 Effluent Discharges......................................................................................................................... 8

A.5 Water Intake...................................................................................................................................8

A.6 Onshore Waste Disposal................................................................................................................. 9

A.7 Marine Debris.................................................................................................................................9

A.8 Support Vessel and Helicopter Traffic ............................................................................................ 9

A.9 Accidents ......................................................................................................................................10

A.9.1 Types of Accidents Evaluated ........................................................................................... 10

A.9.2 Small Fuel Spill .................................................................................................................. 10

A.9.3 Crude Oil Spill (Worst Case Discharge) ............................................................................. 11

A.9.4 Other Accidents Not Analyzed in Detail............................................................................ 15

B.  Affected Environment...........................................................................................17

C.  Impact Analysis.....................................................................................................19

C.1 Physical/Chemical Environment................................................................................................... 19

C.1.1 Air Quality ......................................................................................................................... 19

C.1.2 Water Quality.................................................................................................................... 21

C.2 Seafloor Habitats and Biota.......................................................................................................... 23

C.2.1 Soft Bottom Benthic Communities................................................................................... 23

C.2.2 High‐Density Deepwater Benthic Communities............................................................... 26

C.2.3 Designated Topographic Features.................................................................................... 28

C.2.4 Pinnacle Trend Area Live Bottoms.................................................................................... 28

C.2.5 Live Bottom/Low Relief..................................................................................................... 29

C.3 Threatened, Endangered, and Protected Species and Critical Habitat........................................ 29

C.3.1 Sperm Whale (Endangered).............................................................................................. 31

C.3.2 West Indian Manatee (Endangered)................................................................................. 34

C.3.3 Endangered Mysticete Whales......................................................................................... 35

C.3.4 Non‐Endangered Marine Mammals (Protected).............................................................. 35

C.3.5 Sea Turtles (Endangered/Threatened) ............................................................................. 38

C.3.6 Piping Plover (Threatened) ............................................................................................... 41

C.3.7 Whooping Crane (Endangered) ........................................................................................ 43

C.3.8 Gulf Sturgeon (Threatened).............................................................................................. 44

C.3.9 Smalltooth Sawfish (Endangered)..................................................................................... 45

C.3.10 Beach Mice (Endangered)................................................................................................. 45

C.3.11 Elkhorn Coral (Endangered).............................................................................................. 46
Contents

(Continued)

Page

Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page iii

C.4 Coastal and Marine Birds.............................................................................................................. 46

C.4.1 Marine Birds...................................................................................................................... 46

C.4.2 Shorebirds and Coastal Nesting Birds............................................................................... 49

C.5 Fisheries Resources ...................................................................................................................... 51

C.5.1 Pelagic Communities and Ichthyoplankton ...................................................................... 51

C.5.2 Essential Fish Habitat........................................................................................................ 53

C.6 Archaeological Resources............................................................................................................. 56

C.6.1 Shipwreck Sites................................................................................................................. 56

C.6.2 Prehistoric Archaeological Sites........................................................................................ 57

C.7 Coastal Habitats and Protected Areas.......................................................................................... 58

C.8 Socioeconomic and Other Resources........................................................................................... 61

C.8.1 Recreational and Commercial Fishing .............................................................................. 61

C.8.2 Public Health and Safety ................................................................................................... 63

C.8.3 Employment and Infrastructure ....................................................................................... 63

C.8.4 Recreation and Tourism.................................................................................................... 64

C.8.5 Land Use............................................................................................................................ 65

C.8.6 Other Marine Uses............................................................................................................ 66

D.  Environmental Hazards.........................................................................................66

D.1 Geologic Hazards.......................................................................................................................... 66

D.2 Severe Weather............................................................................................................................ 66

D.3 Currents and Waves ..................................................................................................................... 67

E.  Alternatives ..........................................................................................................67

F.  Mitigation Measures.............................................................................................67

G.  Consultation.........................................................................................................67

H.  Preparers..............................................................................................................67

I.  References.............................................................................................................68
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page iv

List of Tables

Table Page

1 Notices to Lessees and Operators (NTLs) applicable to this Environmental Impact

Analysis (EIA) ......................................................................................................................... 3

2 Matrix of impact‐producing factors and affected environmental resources........................6

3 Conditional probabilities expressed as percent chance that an oil spill starting at

Launch Point 3 will contact a certain parish, county, or coastline within 120 days

(Modified from: BOEMRE, 2011a, Appendix C)................................................................... 13

4 Benthic community data from stations near the lease area and in similar water

depths sampled during the Northern Gulf of Mexico Continental Slope Habitats

and Benthic Ecology Study (From: Wei, 2006; Rowe and Kennicutt, 2009)........................24

5 Federally‐listed endangered and threatened species potentially occurring in the

lease area and along the northern Gulf Coast .................................................................... 30

6 Wildlife refuges, wilderness areas, and State and National parks within the

geographic range of the potential shoreline contacts after 120 days

(From: BOEMRE, 2011a)...................................................................................................... 59

List of Figures

Figure Page

1 Location of Lloyd Ridge Block 621......................................................................................... 2

2 Bathymetric map (in meters) of the lease area showing proposed well surface

locations .............................................................................................................................. 18

3 Location of selected environmental features in relation to the lease area........................42
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page v

Acronyms and Abbreviations

ADIOS Automated Data Inquiry for Oil Spills

Anadarko Anadarko Petroleum Corporation

bbl barrel

BHL bottom hole location

BLPD barrels of liquid per day

BOEM Bureau of Ocean Energy Management

BOEMRE Bureau of Ocean Energy Management,

Regulation and Enforcement

BOP blowout preventer

BOPD barrels of oil per day

B.P. Before Present

CH4 methane

CO carbon monoxide

CO2 carbon dioxide

CEI Coastal Environments, Inc.

CFR Code of Federal Regulations

CGA Clean Gulf Associates

DOCD Development Operations Coordination

Documents

DP dynamically positioned  

DPP Development and Production Plan

EP Exploration Plan  

EA Environmental Assessment

EEZ Exclusive Economic Zone

EFH Essential Fish Habitat

EIA Environmental Impact Analysis

EIS Environmental Impact Statement

ESA Endangered Species Act

EWTA Eglin Water Test Area

FAD fish‐attracting device

FR Federal Register

GEMS Geoscience, Earth and Marine Services,

Inc.

GPS global positioning system

GMFMC Gulf of Mexico Fishery Management

Council

H2S hydrogen sulfide

HAPC Habitat Area of Particular Concern

HFRS Helix Fast Response System

HOSS high‐volume open sea skimmer

HWCG Helix Well Containment Group

IPF impact‐producing factor

LL Lloyd Ridge  

MARPOL International Convention for the

Prevention of Pollution from Ships

MMBO million barrels of oil

MMC Marine Mammal Commission

MMPA Marine Mammal Protection Act

MMS Minerals Management Service

MMSCFD million standard cubic feet per day

MWCC Marine Well Containment Company

NAAQS National Ambient Air Quality Standards

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric

Administration

NOx nitrogen oxides

NPDES National Pollutant Discharge Elimination

System

NPS National Park Service

NRDA Natural Resource Damage Assessment

NTL Notice to Lessees and Operators

NWR National Wildlife Refuge

OBM oil‐based mud

OCS Outer Continental Shelf

OSAT Operational Scientific Advisory Team

OSRA Oil Spill Risk Analysis

OSRP Oil Spill Response Plan

PAH polycyclic aromatic hydrocarbon

PM particulate matter

PSD Prevention of Significant Deterioration

SBM synthetic‐based mud

SHL surface hole location

SOx sulfur oxides

SWSS Sperm Whale Seismic Study

USCG U.S. Coast Guard

USEPA U.S. Environmental Protection Agency

USFWS U.S. Fish and Wildlife Service

VOC volatile organic compound

WCD worst case discharge
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 1

Introduction

Anadarko Petroleum Corporation (Anadarko) is submitting an Initial Exploration Plan (EP) for

Lloyd Ridge Block 621 (LL 621).  The EP includes two wells designated A and B located in the

southwestern corner of the block.  Wells A and B will have their surface hole location (SHL) and

bottom hole location (BHL) in LL 621.  This Environmental Impact Assessment (EIA) provides an

analysis of both planned wells based on their SHLs.

The lease area is 143 miles (230 km) southeast of the nearest shoreline (Louisiana), 196 miles

(315 km) from the onshore support base and helicopter base at Fourchon, Louisiana(Figure 1).  

Water depths atthe wellsites are approximately 2,769‐2,770 m (9,087‐9,089 ft). The drilling rig is

yet to be determined but will be either a dynamically positioned (DP) drillship or a DP

semisubmersible.

This EIA was prepared for submittal to the Bureau of Ocean Energy Management (BOEM),

(formally BOEMRE until 1 October 2011 and formerly Minerals Management Service [MMS]) in

accordance with applicable regulations, and is a project‐ and site‐specific analysis of Anadarko’s

planned activities.  As specified in the Notice to Lessees and Operators (NTL) 2008‐G04, an EIA is

a project‐specific analysis that focuses on the impacts of a specific plan to the extent feasible.  

Potential impacts have been analyzed at a broader level in the Programmatic Environmental

Impact Statement (EIS) for the Outer Continental Shelf (OCS) Oil and Gas Leasing Program

(MMS, 2007a) and in lease sale EISs for the Western and Central Gulf of Mexico Planning Areas

(MMS, 2007b, 2008).  The analyses from these documents are incorporated here by reference.  

Also incorporated is the post‐Macondo incident Draft Supplemental EIS for the Central Planning

Area and the Final Supplemental EIS for the Western Planning Area lease sales (BOEMRE,

2011a,b), which present updated environmental baseline information relative to the Macondo

incident, have been reviewed.

Statistics from offshore drilling in the U.S. Gulf of Mexico provide a reasonable basis for

evaluating oil spill risk during exploratory drilling.  According to Holand (1997), the average

frequency of a loss of well control incident or “blowout” during exploratory drilling in the

U.S. Gulf of Mexico is 0.00593 blowouts per well drilled, or one blowout per 169 exploration

wells drilled.  Similarly, the MMS Safety and Environmental Management Program blowout

incident rate for 1996 to 1999 was approximately five blowouts per 1,000 well starts, or one

blowout per 200 well starts (MMS, 2000).  More recently, in its Draft Supplemental EIS for the

Central Gulf of Mexico Planning Area, BOEMRE confirmed that “significant changes to the spill

rates for the entire OCS are not anticipated” (BOEMRE, 2011a).

Historically, most blowouts have not resulted in oil spills.  Of 151 well blowouts in the Gulf of

Mexico from 1971 to 1995, only 18 (12%) resulted in oil spills, with a total combined volume of

1,000 barrels (bbl) of crude oil and condensate released (MMS, 2000).  Between 1964 and 1999,

almost all offshore spills (94%) from drilling and production‐related operations on the OCS were

less than or equal to 1 bbl in size (Anderson and LaBelle, 2000).  According to BOEMRE’s Interim

Final Drilling Safety Rule (75 Federal Register (FR) 63365 dated 10 October 2010) issued

following the Macondo incident, the baseline risk of a catastrophic blowout is estimated to be

about once every 26 years.
Lloyd Ridge Block 621 

Environmental Impact Analysis for Initial Exploration Plan 

Figure 1. Location of Lloyd Ridge Block 621.
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 3

Anadarko submitted an updated Gulf of Mexico Sub‐Regional Oil Spill Response Plan (OSRP) per

30 Code of Federal Regulations (CFR) 254.2(b) to BSEE.  The plan was approved on 14 March

2012.  The OSRP details Anadarko’s plan for response to rapidly and effectively manage oil spills

that may result from drilling and production operations.  Anadarko has designed its response

program based on a regional capability of response to spills ranging from small operational spills

to a worst case discharge (WCD) from a well blowout.  Anadarko’s spill response program meets

the response planning requirements of the relevant coastal States and applicable Federal oil spill

planning regulations and also includes information regarding Anadarko’s regional oil spill

organization and dedicated response assets, potential spill risks, and local environmental

sensitivities.  The OSRP describes personnel and equipment mobilization, the incident

management team organization, and an overview of actions and notifications to be taken in the

event of a spill.

This EIA is organized into Sections A through I corresponding to the information required by

NTL 2008‐G04.  The main impact‐related discussions are in Section A (Impact‐Producing Factors)

and Section C (Impact Analysis).  Table 1 lists and summarizes the NTLs applicable to this EIA.

Table 1. Notices to Lessees and Operators (NTLs) applicable to this Environmental Impact

Analysis (EIA).

NTL Title Summary

2010‐N10

Statement of Compliance with

Applicable Regulations and

Evaluation of Information

Demonstrating Adequate Spill

Response and Well Containment

Resources

Informs operators using subsea blowout preventers (BOPs) or

surface BOPs on floating facilities that applications for well

permits must include a statement signed by an authorized

company official stating that the operator will conduct all

activities in compliance with all applicable regulations, including

the increased safety measures regulations (75 FR 63346).  

Informs operators that BOEM will be evaluating whether each

operator has submitted adequate information demonstrating

that it has access to and can deploy containment resources to

promptly respond to a blowout or other loss of well control.

2010‐N06

Information Requirements for

Exploration Plans, Development and

Production Plans, and Development

Operations Coordination Documents

on the OCS

Rescinds the limitations set forth in NTL 2008‐G04 regarding a

blowout scenario and worst case discharge scenario, and

provides guidance regarding the information required in blowout

scenario and worst case discharge scenario descriptions.

2009‐G40 Deepwater Benthic Communities

Guidance for avoiding and protecting high‐density deepwater

benthic communities (including chemosynthetic and deepwater

coral communities) from damage caused by Outer Continental

Shelf (OCS) oil and gas activities in water depths greater than

300 m (984 ft).  Prescribes separation distances of 610 m

(2,000 ft) from each mud and cuttings discharge location and

76 m (250 ft) from all other seafloor disturbances.

2009‐G39 Biologically‐Sensitive Underwater

Features and Areas

Guidance for avoiding and protecting biologically sensitive

features and areas (i.e., topographic features, pinnacles, low

relief live bottom areas, and other potentially sensitive biological

features) when conducting OCS operations in water depths less

than 300 m (984 ft) in the Gulf of Mexico.
Table 1.  (Continued.)

Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 4

NTL Title Summary

2009‐G06 Military Warning and Water Test

Areas

Provides contact links to individual command headquarters for

the military warning and water test areas in the Gulf of Mexico.  

Lease stipulations require lessees or designated operators to

enter into an agreement with the appropriate individual military

command headquarters concerning the control of

electromagnetic emissions and use of boats and aircraft in the

applicable warning area or water test area before commencing

such traffic.

2008‐G04

Information Requirements for

Exploration Plans and Development

Operations Coordination Documents

Guidance on the information requirements for OCS plans,

including EIA requirements and information regarding

compliance with the provisions of the Endangered Species Act

and Marine Mammal Protection Act.

Joint 2012‐

G01

Vessel Strike Avoidance and

Injured/Dead Protected Species

Reporting

Recommends protected species identification training,

recommends that vessel operators and crews maintain a vigilant

watch for marine mammals and slow down or stop their vessel

to avoid striking protected species, and requires operators to

report sightings of any injured or dead protected species.

BSEE

2012‐G01

Marine Trash and Debris Awareness

and Elimination

Instructs operators to exercise caution in the handling and

disposal of small items and packaging materials; requires the

posting of placards at prominent locations on offshore vessels

and structures; and mandates a yearly marine trash and debris

awareness training and certification process.

2005‐G07 Archaeological Resource Surveys

and Reports

Provides guidance on regulations regarding archaeological

discoveries, specifies requirements for archaeological resource

surveys and reports, and outlines options for protecting

archaeological resources.
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 5

A.  Impact‐Producing Factors

Table 2 is a matrix of impact‐producing factors (IPFs) and potentially affected environmental

resources adapted from Form MMS‐142.  An “X” indicates that an IPF could reasonably be

expected to affect a certain resource, and a dash (‐‐) indicates no impact or negligible impact.  

Where there may be an effect, an analysis is provided in Section C.  Potential IPFs for the

proposed activity are listed below and briefly discussed in the following sections.

 Drilling rig presence (including noise

and lights)

 Physical disturbance to the seafloor

 Air pollutant emissions

 Effluent discharges

 Water intake

 Onshore waste disposal

 Marine debris

 Support vessel and helicopter traffic

 Accidents

A.1 Drilling Rig Presence (including noise and lights)

Two types of exploratory drilling rigs are available for this project:

 DP drillship; and

 DP semisubmersible

DP drillships and DP semisubmersibles use a global positioning system (GPS), specific computer

software, and sensors in conjunction with and their own propellers and thrusters to maintain

position.  Essentially, through satellite navigation and, the location of the vessel is precisely

monitored, and thrusters positioned at various locations about the vessel’s hull are activated to

provide any required stationkeeping adjustment.  This allows operations at sea where mooring

or anchoring is not feasible.

The drilling vessel for the wells proposed in this EP will be on site for an estimated 120 days

(60 days/well).  The physical presence of the drilling rig in the ocean can attract pelagic fishes

and other marine life, as discussed in Section C.5.1.

Drilling operations produce noise that includes strong tonal components at low frequencies and,

in some cases, infrasonic frequencies (MMS, 2000).  Drilling noise from drillships and

semisubmersibles is not particularly intense and is strongest at low frequencies, averaging

10 to 500 Hz (Richardson et al., 1995).  From a drilling rig, sound and vibration paths to the

water flow either through the air or through the risers (MMS, 2000).  Drilling rigs also maintain

exterior lighting for navigational and aviation safety in accordance with applicable Federal safety

regulations.
Lloyd Ridge Block 621 

Environmental Impact Analysis for Initial Exploration Plan 

Table 2. Matrix of impact‐producing factors and affected environmental resources. X = potential impact; dash (‐‐) = no imp

Environmental Resources

Impact‐producing Factors

Drilling Rig

Presence (incl.

noise & lights)

Physical

Disturbance

to Seafloor

Air

Pollutant

Emissions

Effluent

Discharges

WaterIntake

Onshore

Waste

Disposal

Marine

Debris

Sup

Vesse

Tra

Physical/Chemical Environment

Air quality and greenhouse gases  ‐‐ ‐‐ X(9) ‐‐ ‐‐  ‐‐ ‐‐ Water quality  ‐‐ ‐‐ ‐‐ X ‐‐  ‐‐ ‐‐ 

Seafloor Habitats and Biota

Soft bottom benthic communities  ‐‐ X ‐‐ X ‐‐  ‐‐ ‐‐ High‐density deepwater benthic communities  ‐‐ ‐‐(4) ‐‐ X(4) ‐‐  ‐‐ ‐‐ Designated topographic features  ‐‐ ‐‐(1) ‐‐ ‐‐(1) ‐‐  ‐‐ ‐‐ Pinnacle trend area live bottoms  ‐‐ ‐‐(2) ‐‐ ‐‐(2) ‐‐  ‐‐ ‐‐ Live bottom/Low‐Relief  ‐‐ ‐‐(3) ‐‐ ‐‐(3) ‐‐  ‐‐ ‐‐ 

Threatened, Endangered, and Protected Species and Critical Habitat

Sperm whale (endangered) X(8) ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ XWest Indian manatee (endangered)  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ XEndangered mysticete whales  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Non‐endangeredmarinemammals(protected) X ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Sea turtles (endangered/threatened) X(8) ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ XPiping Plover (threatened)  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Whooping Crane (endangered)  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Gulf sturgeon (threatened)  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Smalltooth sawfish (endangered) ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Beach mice (endangered) ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Elkhorn coral (endangered) ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

Coastal and Marine Birds

Marine birds X ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Shorebirds and coastal nesting birds  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

Fisheries Resources

Pelagic communities and ichthyoplankton X ‐‐ ‐‐ X X ‐‐ ‐‐ Essential Fish Habitat X ‐‐ ‐‐ X X  ‐‐ ‐‐ 

Archaeological Resources

Shipwreck sites  ‐‐ ‐‐(7) ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Prehistoric archaeological sites  ‐‐ ‐‐(7) ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

Coastal Habitats and Protected Areas

Beaches  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Wetlands and seagrass beds  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Coastal wildlife refuges and wilderness areas  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

Socioeconomic and Other Resources

Recreational and commercial fishing X ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Public health and safety  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Employment and infrastructure  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Recreation and tourism  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Land use  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ Other marine uses  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ 

WCD = worst case discharge.
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 7

Table 2 Footnotes and Applicability:

(1) Activities that may affect a marine sanctuary or topographic feature.  Specifically, if the well, rig site, or any

anchors will be on the seafloor within the following:

(a) 4‐mi zone of the Flower Garden Banks, or the 3‐mi zone of Stetson Bank;

(b) 1,000‐m, 1‐mi, or 3‐mi zone of any topographic feature (submarine bank) protected by the Topographic

Features Stipulation attached to an Outer Continental Shelf (OCS) lease;

(c) Essential Fish Habitat (EFH) criteria of 500 ft from any no‐activity zone; or

(d) Proximity of any submarine bank (500‐ft buffer zone) with relief greater than 2 m that is not protected by

the Topographic Features Stipulation attached to an OCS lease.

 Not applicable.  The lease is not within or near a marine sanctuary, topographic feature, or

no‐activity zone.  There are no submarine banks in the blocks.

(2) Activities with any bottom disturbance within an OCS lease block protected through the Live Bottom

(Pinnacle Trend) Stipulation attached to an OCS lease.

 The Live Bottom (Pinnacle Trend) Stipulation is not applicable to the lease area.

(3) Activities within any Eastern Gulf OCS block where seafloor habitats are protected by the Live Bottom

(Low‐Relief) Stipulation attached to an OCS lease.  

 The Live Bottom (Low‐Relief) Stipulation is not applicable to the lease area.

(4) Activities on blocks designated by the BOEM as being in water depths 300 m or greater.

 No impacts on high‐density deepwater benthic communities are anticipated.  There are no features

indicative of high‐density chemosynthetic communities or coral communities within 610 m (2,000 ft) of

any drilling mud/cuttings discharge location.   

(5) Exploration or production activities where H2S concentrations greater than 500 ppm might be encountered.  

 Based on drilling in nearby blocks, Anadarko is requesting that the BOEM classify the area as

“H2S absent.”  Anadarko will submit an H2S Contingency Plan prepared according to 30 CFR 250.490(f)

before conducting the proposed exploration activities.

(6) All activities that could result in an accidental spill of produced liquid hydrocarbons or diesel fuel that you

determine would impact these environmental resources.  If the proposed action is located a sufficient distance

from a resource that no impact would occur, the EIA can note that in a sentence or two.

 Accidental hydrocarbon spills could affect the resources marked (X) in the matrix, and impacts are

analyzed in Section C.

(7) All activities that involve seafloor disturbances, including anchor emplacements, in any OCS block designated

by the BOEM as having high‐probability for the occurrence of shipwrecks or prehistoric sites, including such

blocks that will be affected that are adjacent to the lease block in which your planned activity will occur.  If the

proposed activities are located a sufficient distance from a shipwreck or prehistoric site that no impact would

occur, the EIA can note that in a sentence or two.

 No impacts on archaeological resources are expected.  The lease area is not on the list of high‐probability

blocks for shipwrecks and is well beyond the 60‐m depth contour used by the BOEM as the seaward

extent for prehistoric archaeological site potential in the Gulf of Mexico.

(8) All activities that you determine might have an adverse effect on endangered or threatened marine mammals

or sea turtles or their critical habitats.  

 IPFs that may affect marine mammals, sea turtles, or their critical habitats include drilling rig presence

and emissions, support vessel and helicopter traffic, and accidents.  See Section C.

(9) Production activities that involve transportation of produced fluids to shore using shuttle tankers or barges.

 Not applicable.
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 8

A.2 Physical Disturbance to the Seafloor

In water depths of 600 m (1,969 ft) or greater, DP drillships and DP semisubmersibles disturb

only a very small area of the seafloor around the wellbore (SHL) where the bottom template and

blowout preventer are located.  Depending upon the specific well configuration, this area is

generally about 0.25 ha (0.62 ac).

A.3 Air Pollutant Emissions

Air pollutant emissions are calculated in EP Section G and are estimated to be insignificant.  

Offshore air pollutant emissions will result from operations of the drilling rig, as well as service

vessels and helicopters.  These emissions occur mainly from combustion of diesel fuel.  The

combustion of fuels occurs on diesel‐powered generators, pumps, or motors and from lighter

fuel motors.  Primary air pollutants typically associated with OCS activities are suspended

particulate matter (PM), sulfur oxides (SOx), nitrogen oxides (NOx), volatile organic compounds

(VOCs), and carbon monoxide (CO).

The Air Quality Emissions Report prepared in accordance with BOEM requirements

demonstrates that the projected emissions are below exemption levels set by the applicable

regulations in 30 CFR 250.303.  Based on this and the distance to shore, it can be concluded that

the emissions will not significantly affect the air quality of the onshore area for any of the

criteria pollutants.  No further analysis or control measures are required.

A.4 Effluent Discharges

Effluent discharges are summarized in EP Section F.  All offshore discharges will be in

accordance with requirements of the National Pollutant Discharge Elimination System (NPDES)

General Permit No. GMG 290000 issued by the U.S. Environmental Protection Agency (USEPA).  

Any discharges will be in compliance with the permit terms and monitored as required by the

permit.

Water‐based drilling muds and cuttings will be released at the seafloor during the initial well

intervals before the marine riser that allows their return to the surface is set.  Excess cement

slurry will also be released at the seafloor during casing installation for the riserless portion of

the drilling operations.  Synthetic‐based drilling muds (SBMs) will be collected on the rig and

either reused by the vendor, or transported to Port Fourchon for recycling and/or disposal in an

approved facility.  Cuttings wetted with SBMs will be discharged to the seafloor in accordance

with the NPDES permit.

Other effluent discharges in accordance with the NPDES permit will include excess cement,

non‐contact cooling water, treated sanitary and domestic wastes, deck drainage, desalination

unit brine, uncontaminated fresh water and seawater, and ballast water.

A.5 Water Intake

Seawater will be drawn from the ocean for once‐through, non‐contact cooling of machinery on

the drilling rig.  Section 316(b) of the Clean Water Act requires NPDES permits to ensure that the

location, design, construction, and capacity of cooling water intake structures reflect the best

technology available to minimize adverse environmental impact from impingement and

entrainment of aquatic organisms.  The current NPDES General Permit No. GMG290000 does
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 9

not specify requirements for existing facilities (those that started construction before

16 July 2006).  The rigs being considered for use for activities described in this EP are not

“new” facilities as defined by the NPDES permit and therefore are not subject to the cooling

water intake regulations.

A.6 Onshore Waste Disposal

Wastes generated during drilling are tabulated in EP Section F.  Approximately 50 bbl of trash

will be generated each month of operations or a total of 200 bbls over the life of this project.  

This trash will be transported in disposal bags to shore, where it will be picked up by municipal

operators for final disposal in accordance with applicable regulations.

A.7 Marine Debris

Anadarko will comply with all regulations relating to solid waste handling and disposal, including

the International Convention for the Prevention of Pollution from Ships (MARPOL 73/78)

Annex V requirements and USEPA and U.S. Coast Guard (USCG) regulations, as well as those of

the BOEM.  For example, BOEMRE regulations at 30 CFR 250.300(a) and (b)(6) prohibit operators

from deliberately discharging containers and other similar materials (i.e., trash and debris) into

the marine environment, and 30 CFR 250.300(c) requires durable identification markings on

equipment, tools, and containers (especially drums), and other material.  USEPA and USCG

regulations require operators to become proactive in avoiding accidental loss of solid waste

items by developing waste management plans, posting informational placards, manifesting trash

sent to shore, and using special precautions such as covering outside trash bins to prevent

accidental loss of solid waste.  In addition to the regulations in 30 CFR 250, BSEE issued NTL

2012‐G01, which instructs operators to exercise caution in the handling and disposal of small

items and packaging materials, requires the posting of placards at prominent locations on

offshore vessels and structures, and mandates a yearly marine trash and debris awareness

training and certification process.

A.8 Support Vessel and Helicopter Traffic

Anadarko will use existing shorebase facilities and helicopter base at Fourchon, Louisiana, for

onshore support for vessel activities. No terminal expansion or construction is planned.

The project will be supported by one crew boat and one supply vessel.  The crew vessel will

make one round‐trip per week, and the supply vessel will make two round‐trips per week.  The

boats typically will move to the project area via the most direct route from the shorebase.

A helicopter will make one round‐trip daily between the drilling rig and the heliport.  The

helicopter will be used to transport personnel and small supplies and will normally take the

most direct route of travel between the shorebase and the lease area when air traffic and

weather conditions permit.  Helicopters typically maintain a minimum altitude of 213 m (700 ft)

while in transit offshore, 305 m (1,000 ft) over unpopulated areas or across coastlines, and

610 m (2,000 ft) over populated areas and sensitive habitats such as wildlife refuges and park

properties.
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Environmental Impact Analysis for Initial Exploration Plan Page 10

A.9 Accidents

A.9.1 Types of Accidents Evaluated

The analysis in this EIA focuses on two potential accidents:

 A small fuel spill, which is the most likely type of spill during OCS exploration activities; and

 The WCD for this EP, which is an oil spill resulting from an uncontrolled blowout.

The following subsections summarize assumptions about the sizes and fates of these spills, as

well as Anadarko’s spill response plans.  Impacts are analyzed in Section C.

MMS (2007b) and BOEMRE (2011a,b) analyze three other types of accidents: chemical spills,

vessel collisions, and loss of well control.  These types of accidents are discussed briefly in

Section A.9.4.

A.9.2 Small Fuel Spill

Spill Size.  According to the analyses in MMS (2007b) and BOEMRE (2011a,b), the most likely

type of small spill (<1,000 bbl) as a result of OCS activities is a minor diesel fuel spill.  Historically,

most diesel spills have been <1 bbl, and this size is predicted to be the most common in ongoing

and future OCS activities in the Western and Central Gulf of Mexico Planning Areas.  As the spill

size increases, the incident rate declines dramatically (MMS, 2007b; BOEMRE, 2011a,b).  The

average size for spills <1 bbl is 0.07 bbl, and the median size for spills of 1 to 10 bbl is 3 bbl

(MMS, 2007b).  For this analysis, a small diesel fuel spill of 3 bbl is assumed.  Operational

experience suggests that the most likely cause of such a spill would be a hose rupture resulting

in the loss of the contents of a fuel transfer hose, which is less than 3 bbl.

Spill Fate.  The fate of a small fuel spill in the lease area would depend on meteorological and

oceanographic conditions at the time, as well as the effectiveness of spill response activities.  

However, given the open ocean location of the lease area and response actions, it is expected

that impacts from a small spill would be minimal (BOEMRE, 2011a,b).

The water‐soluble fractions of diesel are dominated by two‐ and three‐ringed polycyclic

aromatic hydrocarbons (PAHs), which are moderately volatile (National Research Council, 2003).  

The constituents of these oils are light to intermediate in molecular weight and can be readily

degraded by aerobic microbial oxidation.  Due to its light density, diesel will not sink to the

seafloor.  Diesel dispersed in the water column can adhere to suspended sediments, but this

generally occurs only in coastal areas with high suspended solids loads (National Research

Council, 2003) and would not be expected to occur to any appreciable degree in offshore waters

of the Gulf of Mexico.  Diesel oil is readily and completely degraded by naturally occurring

microbes (National Oceanic and Atmospheric Administration [NOAA], 2006).

For purposes of this EIA, the fate of a small diesel fuel spill was estimated using NOAA’s

Automated Data Inquiry for Oil Spills (ADIOS2) model.  This model uses the physical properties

of oils in its database to predict the rate of evaporation and dispersion over time, as well as

changes in the density, viscosity, and water content of the product spilled.  It is estimated that

over 90% of a small diesel spill would be evaporated or dispersed within 24 hours.  The area of

the sea surface with diesel fuel on it during this 24‐hour period would range from 0.5 to 5 ha

(1.2 to 12 ac) depending on sea state and weather conditions.
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Environmental Impact Analysis for Initial Exploration Plan Page 11

The ADIOS2 results, coupled with spill trajectory information discussed below for a large spill,

indicate that a small fuel spill would not have any impacts on coastal or shoreline resources.  

The lease area is 143 miles (230 km) from the nearest shoreline (Louisiana).  Modeling results

discussed below indicate that a spill in the lease area would have a 4% or less probability of

reaching the coastal areas of Louisiana within 10 days after a spill.  By that time, essentially

100% of a small fuel spill would have been dispersed or evaporated by natural processes,

without taking into account Anadarko’s response measures.  MMS (2007b) similarly concluded

that spills <1,000 bbl are not expected to persist as a slick on the surface of the water beyond a

few days and are unlikely to make landfall or reach coastal waters prior to breaking up.  MMS

(2007b) noted that this conclusion is supported by a previous analysis of 3‐day trajectory model

runs, previous weathering analyses, and historical records of spill incidents.

Spill Response.  In the unlikely event the shipboard prevention procedures fail to prevent a fuel

spill, response equipment and trained personnel would be activated so that any spill effects

would be localized and would result only in short‐term environmental consequences.  

EP Section 9b provides a detailed discussion of Anadarko’s response to a spill.

A.9.3 Crude Oil Spill (Worst Case Discharge)

Spill Size.  In accordance with requirements of NTL 2010‐N06, Anadarko has estimated a WCD

for this EP as 39,501 barrels of oil.  The detailed analysis of this calculation can be found in

EP Section H.

Historically, blowouts are rare events and most do not result in oil spills.  Holand (1997)

estimated a probability of 0.0021 for a deep drilling blowout during exploration drilling based on

U.S. Gulf of Mexico data.  An updated analysis using the SINTEF database estimates a blowout

frequency of 0.0017 per exploratory well for non‐North Sea locations (International Association

of Oil & Gas Producers, 2010).  As noted by MMS (2007b), from 1992 to 2005, half of blowouts

lasted less than half a day, and fewer than 10% of blowouts resulted in spilled oil.  BOEMRE is in

the process of updating these spill frequency estimates to include the recent Macondo event;

however, significant changes to the spill rates for the entire OCS are not anticipated

(BOEMRE, 2011a,b).  As noted in the Introduction, the baseline risk of a catastrophic blowout is

estimated to be once every 26 years (BOEMRE Interim Final Drilling Safety Rule, 75 FR 63365,

10 October 2010).

Included in EP Section H are Anadarko’s calculations and information as required by

NTL 2010‐N06, including descriptions of measures to prevent a blowout, reduce the likelihood of

a blowout, and conduct effective and early intervention in the event of a blowout.  Anadarko

will also comply with NTL 2010‐N10 and the Interim Final Drilling Safety Rule, which specifies

additional safety measures for OCS activities.

Spill Trajectory.  The fate of a large oil spill in the lease area would depend on meteorological

and oceanographic conditions at the time.  The Oil Spill Risk Analysis (OSRA) model is a

computer simulation of oil spill transport that uses realistic data for winds and currents to

predict spill fate.  Although this model has received some criticism recently (Earthjustice, 2011),

it is still the most widely scientifically accepted model for estimating the fate of small fuel spills.  

The primary criticism of the OSRA model results as provided in Ji et al. (2004) was that the

model did not evaluate the fate of a spill over time periods longer than 30 days, nor does it

predict the fate of a release that continues over a period of weeks or months, as in the
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Environmental Impact Analysis for Initial Exploration Plan Page 12

Macondo incident.  Also as noted by Ji et al. (2004), the OSRA model does not take into account

the chemical composition or biological weathering of oil spills, the spreading and splitting of oil

spills, or spill response activities.  The model does not assume a particular spill size but has

generally been used by the BOEMRE/MMS to evaluate contact probabilities for spills greater

than 1,000 bbl.

To address this criticism, a special OSRA run was conducted for the recent BOEMRE Central and

Western Gulf of Mexico Planning Area Supplemental EISs (BOEMRE, 2011a,b) in order to

estimate the impacts of a possible future catastrophic long‐duration oil spill.  In this OSRA model

run a hypothetical high volume, long‐duration oil spill was assumed to have occurred, and the

analysis emphasized modeling a spill that continued for 90 consecutive days, with each

trajectory tracked for up to 120 days.

The OSRA model run for this revised analysis was conducted for five hypothetical launch points

in the Central and Western Gulf of Mexico Planning Areas.  These launch points were

deliberately located in areas identified as having a high possibility of containing large oil

reserves.  

The five launch point areas were as follows:

1. Central Gulf of Mexico shelf area west of the Mississippi River (28.98660° N

latitude, 92.17851° W longitude);

2. Central Gulf of Mexico shelf area east of the Mississippi River (29.91388° N latitude,

88.15338° W longitude);

3. Central Gulf of Mexico slope area (27.31998° N latitude, 90.22203° W longitude);

4. Western Gulf of Mexico shelf area (27.55423° N latitude, 96.76627° W longitude); and

5. Western Gulf of Mexico slope area (27.51367° N latitude, 94.51836° W longitude).

The results for Launch Point 3, which are the most applicable to the project area and within the

Central Planning Area, are presented in Table 3.

OSRA is a preliminary risk assessment model.  In the event of an actual oil spill, real‐time

monitoring and trajectory modeling would be conducted using current and wind data available

from the rigs and permanent production structures in the area.  Satellite and aerial monitoring

of the plume and real‐time trajectory modeling using wind and current data would continue on

a daily basis to help position equipment and human resources throughout the duration of any

major spill or uncontrolled release.

Weathering.  Following an oil spill, several physical, chemical, and biological processes,

collectively called weathering, interact to change the physical and chemical properties of the oil,

influencing potential effects to marine organisms and ecosystems.  The most important

weathering processes include spreading, evaporation, dissolution, dispersion into the water

column, formation of water‐in‐oil emulsions, photochemical oxidation, microbial degradation,

adsorption to suspended particulate matter, and stranding on shore or sedimentation to the

seafloor (National Research Council, 2003).
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Environmental Impact Analysis for Initial Exploration Plan Page 13

Table 3. Conditional probabilities expressed as percent chance that an oil spill starting at

Launch Point 3 will contact a certain parish, county, or coastline within 120 days

(Modified from: BOEMRE, 2011a, Appendix C).

Season Winter Spring Summer Fall

Day 3 10 30 120 3 10 30 120 3 10 30 120 3 10 30 120

County or Parish Percent Chance

Cameron, Texas  ‐‐  ‐‐  ‐‐  2  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  2  ‐‐  ‐‐  ‐‐  2

Willacy, Texas  ‐‐  ‐‐  ‐‐  3  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  2  ‐‐  ‐‐  ‐‐  3

Kenedy, Texas  ‐‐  ‐‐  ‐‐  8  ‐‐  ‐‐  ‐‐  1  ‐‐  ‐‐  ‐‐  9  ‐‐  ‐‐  ‐‐  5

Kleberg, Texas  ‐‐  ‐‐  1 6  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  4  ‐‐  ‐‐  1 6

Nueces, Texas  ‐‐  ‐‐  1 6  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  2  ‐‐  ‐‐  1 2

Aransas, Texas  ‐‐  ‐‐  ‐‐  5  ‐‐  ‐‐  ‐‐  1  ‐‐  ‐‐  ‐‐  3  ‐‐  ‐‐  ‐‐  2

Calhoun, Texas  ‐‐  ‐‐  1 6  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  6  ‐‐  ‐‐  1 4

Matagorda, Texas  ‐‐  ‐‐  2 17  ‐‐  ‐‐  3 4  ‐‐  ‐‐  ‐‐  11  ‐‐  ‐‐  1 6

Brazoria, Texas  ‐‐  ‐‐  3 12  ‐‐  ‐‐  1 3  ‐‐  ‐‐  2 8  ‐‐  ‐‐  1 5

Galveston, Texas  ‐‐  ‐‐  3 10  ‐‐  ‐‐  3 6  ‐‐  ‐‐  2 5  ‐‐  ‐‐  1 4

Jefferson, Texas  ‐‐  ‐‐  1 4  ‐‐  ‐‐  7 9  ‐‐  ‐‐  1 1  ‐‐  ‐‐  ‐‐  2

Cameron, Louisiana  ‐‐  ‐‐  1 4  ‐‐  ‐‐  11 12  ‐‐  1 1 4  ‐‐  ‐‐  ‐‐  4

Vermilion, Louisiana  ‐‐  ‐‐  1 2  ‐‐  ‐‐  5 6  ‐‐  1 1 2  ‐‐  ‐‐  ‐‐  ‐‐ 

Iberia, Louisiana  ‐‐  ‐‐  ‐‐  1  ‐‐  ‐‐  4 4  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 

Terrebonne, Louisiana  ‐‐  1 2 3  ‐‐  4 12 14  ‐‐  ‐‐  ‐‐  2  ‐‐  ‐‐  ‐‐  ‐‐ 

Lafourche, Louisiana  ‐‐  ‐‐  1 1  ‐‐  2 8 10  ‐‐  ‐‐  1 2  ‐‐  ‐‐  ‐‐  ‐‐ 

Jefferson, Louisiana  ‐‐  ‐‐  ‐‐  1  ‐‐  ‐‐  2 2  ‐‐  ‐‐  1 1  ‐‐  ‐‐  ‐‐  ‐‐ 

Plaquemines, Louisiana  ‐‐  ‐‐  ‐‐  1  ‐‐  2 10 12  ‐‐  ‐‐  1 2  ‐‐  ‐‐  ‐‐  ‐‐ 

Jackson, Mississippi  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  1 1  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 

Baldwin, Alabama  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  1 1  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 

Bay, Florida  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  1  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 

Franklin, Florida  ‐‐  ‐‐  ‐‐  1  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 

Monroe, Florida  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  1  ‐‐  ‐‐  ‐‐  1

Dade, Florida  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  1  ‐‐  ‐‐  ‐‐  ‐‐ 

“‐‐” = Values <1.0%.  Areas where there is <0.5% chance of contact within 120 days are not shown.

Weathering decreases the concentration of oil and produces changes in its chemical

composition, physical properties, and toxicity.  The more toxic, light aromatic and aliphatic

hydrocarbons are lost rapidly by evaporation and dissolution from a slick on the water surface.  

Evaporated hydrocarbons are degraded rapidly by sunlight.  Biodegradation of oil on the water

surface and in the water column by marine bacteria removes first the n‐alkanes and then the

light aromatics from the oil.  Other petroleum components are biodegraded more slowly.  

Photo‐oxidation attacks mainly the medium and high molecular weight PAHs in the oil on the

water surface.

Spill Response.  BOEMRE has issued recent NTLs following the Macondo spill that clarify

additional oil‐spill prevention and response planning requirements.  These NTLs are summarized

in Table 2, and additional BOEMRE (2011a) guidance is provided below.  

NTL 2010‐N10 – Statement of Compliance with Applicable Regulations and Evaluation of

Information Demonstrating Adequate Spill Response and Well Containment Resources:  

This NTL, effective 8 November 2010, applies only to operators conducting operations using

subsea or surface blowout preventers (BOPs) on floating facilities.  It explains that lessees

and operators submit a statement signed by an authorized company official with each

application for a well permit indicating that they will conduct all of their authorized activities

in compliance with all applicable regulations, including the Increased Safety Measures
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 14

Regulations at 75 FR 63346.  The NTL also informs lessees that BOEMRE will be evaluating

whether or not each operator has submitted adequate information demonstrating that it

has access to and can deploy surface and subsea containment resources that would be

adequate to promptly respond to a blowout or other loss of well control.  The NTL notifies

the operator that BOEMRE intends to evaluate the adequacy of each operator to comply in

the operator’s current OSRP; therefore, there is an incentive for voluntary compliance.

NTL 2010‐N06 – Information Requirements for Exploration Plans, Development and

Production Plans, and Development Operations Coordination Documents on the OCS:

This NTL, effective 18 June 2010, explains the procedures for the lessee or operator to

submit supplemental information for new or previously submitted EPs, Development and

Production Plans (DPPs), or Development Operations Coordination Documents (DOCDs).  

The required supplemental information includes the following: 1) a description of the

blowout scenario as required by 30 CFR 250.213(g) and 250.243(h); 2) a description of their

assumptions and calculations used in determining the volume of the WCD required by

30 CFR 250.219(a)(2)(iv) (for EPs) or 30 CFR 250.250(a)(2)(iv) (for DPPs and DOCDs); and

3) a description of the measures proposed that would enhance the ability to prevent a

blowout, to reduce the likelihood of a blowout, and to conduct effective and early

intervention in the event of a blowout, including the arrangements for drilling relief wells

and any other measures proposed.  The early intervention methods of the third

requirement could actually include the surface and subsea containment resources that

BOEMRE announced in NTL 2010‐N10, which states that BOEM will begin reviewing to

ensure that the measures are adequate to promptly respond to a blowout or other loss of

well control.

Anadarko submitted an updated Gulf of Mexico Sub‐Regional Oil Spill Response Plan (OSRP) per

30 Code of Federal Regulations (CFR) 254.2(b) to BSEE.  The plan was approved on 14 March

2012.  The OSRP provides a detailed plan for Anadarko to respond to and rapidly and effectively

manage oil spills that may result from drilling and production operations.  The OSRP contains

detailed information on “Quick Response” procedures including

 responsibilities of all Anadarko and contract personnel to report any observed discharge

from known or unknown sources;

 procedures to locate and determine the size of a discharge; and

 Contact information for alerting the spill management team complete with names, phone

numbers, and locations.

In the event of a WCD, Anadarko has access to surface and subsea response/containment

capabilities that could be implemented through various organizations under contract.  

Anadarko's primary spill response equipment provider is Clean Gulf Associates (CGA).

CGA has four skimming vessels capable of operating in shallow waters and offshore/nearshore

areas.  These vessels have oleophilic brush pack skimming systems operating in troughs built

into the hulls; below deck storage; and marine electronics packages including marine, aircraft

and company frequency radios, radar, moving map plotters, GPS, satellite phone, and depth

finders.  CGA also offers nine Fast Response Systems staged throughout the Gulf of Mexico

available for offshore use.
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Environmental Impact Analysis for Initial Exploration Plan Page 15

The CGA high‐volume open sea skimmer (HOSS) barge consists of a skimming system built into

an oil recovery barge.  There are four 1,000‐bbl recovered oil storage tanks built into the hull

where oil can be separated and offloaded.  Skimming operations are conducted from the control

room overlooking the skimmer deck.  The estimated daily recovery capacity for the HOSS barge

is approximately 43,000 bbl.

CGA is currently adding to its equipment stockpile and has recently acquired 11 sets of

Koseq skimming arms and two Aqua Guard skimmers.  In addition, an x‐band radar/infrared

tracking system is installed on the HOSS barge.

Anadarko also has a contract with the Marine Spill Response Corporation (MSRC) for additional

spill response equipment.  MSRC has a dedicated fleet for the Atlantic/Gulf of Mexico region and

has additional available equipment staged throughout the U.S. MSRC stages equipment

throughout the Gulf of Mexico; including seven Oil Spill Response Vessels (OSRV), two Fast

Response Vessels (FRV), five offshore barges (OSRB), five platform supply vessels (PSV), and

15 shallow water barges.  Various equipment is outfitted with x‐band and infrared technology.

MSRC has recently completed a large expansion of its resources and capability in the Gulf of

Mexico, with particular focus on deepwater.  The expansion is known as “Deep Blue.”  

Additional MSRC capabilities and a complete equipment listing is available on‐line at:

http://www.msrc.org/.

Anadarko also is a member of the Marine Well Containment Company (MWCC).  In the event of

an incident, MWCC can provide a 15,000‐psi single ram capping stack and dispersant injection

capability.  MWCC can also install and operate the interim containment system, including subsea

flowlines, manifold, and risers.  The interim system is engineered to be used in depths up to

3,048 m (10,000 ft) and has the capacity to contain 60,000 barrels of liquid per day (BLPD)

(and 120 million standard cubic feet per day [MMSCFD] of gas) with potential for expansion.

In addition, Anadarko is a member of the Helix Well Containment Group (HWCG), a part of the

Helix Fast Response System (HFRS), and has available all the common response equipment and

services of the HWCG.  Anadarko’s membership allows access to subsea well containment and

well shut‐in equipment including the Q4000 and Helix Producer I vessels to facilitate control and

containment of spills.  At full production capacity, the HFRS can handle up to approximately

55,000 BOPD; 70,000 BLPD; and 95 MMSCFD of gas at 10,000 psi in water depths to 2,438 m

(8,000 ft).  HWCG also can provide a 10,000‐ or 15,000‐psi dual ram capping stacks, in addition

to those available through MWCC.

See EP Section H for a detailed description of Anadarko’s site‐specific response to the WCD for

this plan.

A.9.4 Other Accidents Not Analyzed in Detail

MMS (2007b) discusses three other types of accidents: chemical spills, vessel collisions, and loss

of well control.  The information from the EIS on these topics remains valid and is incorporated

by reference into this document.  These accidents are discussed briefly below along with a

hydrogen sulfide (H2S) release.  There are no other site‐specific issues raised by well drilling

proposed in this EP.
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Environmental Impact Analysis for Initial Exploration Plan Page 16

Chemical Spills.  Chemicals are stored and used to condition drill muds and during production

and in well completions, stimulation, and workover procedures.  The relative quantity of their

use is reflected in the largest volumes spilled.  Completion fluids are the largest quantity used

and comprise the largest releases.  Between 5 and 15 chemical spills are anticipated each year,

with the majority being <50 bbl in size.  The most common chemicals spilled are methanol,

ethylene glycol, and zinc bromide.  Additional production chemicals are needed in deepwater

operations where gas hydrates tend to form.  Spill volumes are anticipated to remain about the

same, but spill frequency can be expected to decrease because of advances in subsea processing

(BOEMRE, 2011a,b).

Riser Disconnect SBM Spills.  In deepwater drilling, SBMs are preferred over petroleum oil‐based

muds (OBMs) due to the superior environmental properties of SBMs.  The synthetic base fluid

used in SBMs are less toxic to the marine environment and have the potential to biodegrade.  

SBMs have been used in the Gulf of Mexico since the mid‐1990s, and between 5 and 20 SBM

releases are anticipated each year as a result of offshore drilling programs.  The majority of

these releases are <50 bbl in size, but accidental riser disconnects may result in the release of

medium (238 to 2,380 bbl) to large (>2,381 bbl) quantities of drilling fluids.  Riser disconnect

accidents are of particular concern when SBMs are in use (BOEMRE, 2011c).

Vessel Collisions.  BOEMRE data show that from 1996 to 2009 there were 226 OCS‐related

collisions.  Most collision mishaps are the result of service vessels colliding with platforms or

vessel collisions with pipeline risers.  Approximately 10% of vessel collisions with platforms in

the OCS resulted in diesel spills, and in several collision incidents fires resulted from

hydrocarbon releases.  To date, the largest diesel spill associated with a collision occurred in

1979 when an anchor‐handling boat collided with a drilling platform in the Main Pass leasing

area, spilling 1,500 bbl.  Diesel fuel is the product most frequently spilled, although oil, natural

gas, corrosion inhibitor, hydraulic fluid, and lube oil have also been released as the result of

vessel collisions.  Human error accounts for approximately half of all reported vessel collisions

from 2006 to 2009.  As summarized in MMS (2007b) and BOEMRE (2011a), vessel collisions

occasionally occur during routine operations.  Some of these collisions have caused spills of

diesel fuel or chemicals.  Anadarko will comply with all USCG‐ and BOEMRE‐mandated safety

requirements to minimize the potential for vessel collisions.

Loss of Well Control.  A loss of well control is the uncontrolled flow of a reservoir fluid that may

result in the release of gas, condensate, oil, drilling fluids, sand, or water.  Loss of well control is

a broad term that includes very minor up to the most serious well control incidents, while

blowouts are considered to be a subset of more serious incidents with greater risk of oil spill or

human injury (MMS, 2007b).  Loss of well control may result in the release of synthetic drilling

fluid or loss of oil.  Anadarko has a robust system in place to prevent loss of well control.  

Measures to prevent a blowout, reduce the likelihood of a blowout, and conduct effective and

early intervention in the event of a blowout are described in EP Section H as required by

NTL 2010‐06.  The potential for a loss‐of‐well‐control event will be minimized by adhering to the

requirements of applicable regulations such as the Interim Final Drilling Safety Rule and

NTL 2010‐N10, which specify additional safety measures for OCS activities.

H2S Release.  The proposed well locations A and B in LL 621 will test stratigraphic sections similar

to that penetrated in the Cheyenne Field located 15 miles to the north.  That field contains three

wells, LL 399 #1, #2, and #3.  No concentration of hydrogen sulfide was encountered in these

wells.  Therefore, Anadarko will request that the LL Block 621 area be classified as an area where

the absence of H2S has been confirmed.
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Environmental Impact Analysis for Initial Exploration Plan Page 17

B.  Affected Environment

The lease area is in the central Gulf of Mexico, 143 miles (230 km) from the nearest shoreline

(Louisiana), and 196 miles (315 km) from the onshore support base at Port Fourchon, Louisiana

(Figure 1).

Based on the Site Clearance Survey by Geoscience, Earth and Marine Services, Inc. (GEMS)

(2009), water depths at the wellsites range from 2,769.71 to 2,770.32 m (9,087 to 9,089 ft)

(Figure 2).  There is no evidence of significant seafloor or subsurface faulting, fluid expulsion

features, or high‐density deepwater benthic communities near the wellsites (GEMS, 2009).

A detailed description of the regional affected environment is provided in recent lease sale EISs,

including meteorology, oceanography, geology, air and water quality, benthic communities,

threatened and endangered species, biologically sensitive resources, archaeological resources,

socioeconomic conditions, and other marine uses (MMS, 2007b, 2008).  These regional

descriptions remain valid and are incorporated by reference.  General background information is

presented below, and brief descriptions of each potentially affected resource, including

site‐specific and/or new information if available, are presented in Section C.

The Macondo spill resulted in impacts to water quality in the area of the spill.  In addition to the

oil slick on the sea surface, plumes of submerged oil droplets were produced when subsea

dispersants were applied at the wellhead (Camilli et al., 2010; Hazen et al., 2010; Joint Analysis

Group, 2010a,b,c).  Despite limited information on the water quality of deep water, it is clear

that the condition of the offshore waters of the Gulf of Mexico was altered by the Macondo

event.  Various monitoring efforts and environmental studies are in progress, but it is not

currently possible to precisely estimate the long‐term impacts the spill will have on offshore

water quality (BOEMRE, 2011a,b).

The lease area is located approximately 105 miles (169 km) southeast of the Macondo spill site.  

Based on an analysis of satellite imagery (ESRI, 2010), the surface slick did extend over the lease

area occasionally during that event and the water quality in the lease area may have been

temporarily affected.  Prior to the Macondo incident, water quality in deep, offshore waters of

the Gulf of Mexico was expected to be good, with low levels of contaminants (Kennicutt, 2000).  

Based on the information currently available, there is no reason to expect any change in water

quality conditions in the lease area from those predicted in the recent lease sale EISs (MMS,

2007b, 2008; BOEMRE, 2011a,b).
Lloyd Ridge Block 621 

Environmental Impact Analysis for Initial Exploration Plan 

Figure 2. Bathymetric map (in meters) of the lease area showing proposed well surface locations.
Lloyd Ridge Block 621 October 2011

Environmental Impact Analysis for Initial Exploration Plan Page 19

C.  Impact Analysis

This section analyzes the potential direct and indirect impacts of routine activities and accidents.  

Impacts have been analyzed extensively in recent lease sale EISs for the Central and Western

Gulf of Mexico Planning Areas (MMS, 2007b, 2008; BOEMRE, 2011a,b) as well as the

Environmental Assessment (EA) for Gulf of Mexico deepwater operations and activities

(MMS, 2000).  The information in these documents is incorporated by reference.  Potential

site‐specific issues are addressed in this section.

C.1 Physical/Chemical Environment

C.1.1 Air Quality

There are no site‐specific air quality data for the project area due to the distance from shore.  

Because of the distance from shore‐based pollution sources and the lack of sources offshore, air

quality at the wellsites is expected to be good.  The attainment status of Federal OCS waters is

unclassified because there is no provision in the Clean Air Act for classification of areas outside

State waters (MMS, 2007b).

As noted earlier, based on calculations made pursuant to applicable regulations, emissions from

drilling activities are not expected to be significant as they are below exemption levels.  

Therefore, the only potential effects to air quality would be from routine air pollutant emissions,

a small fuel spill, and a large oil spill (WCD).

BOEMRE has reexamined the analysis for air quality presented in MMS (2007b, 2008) based on

additional information and in consideration of the Macondo oil spill event.  No substantial new

information was found that would alter the potential impacts on air quality presented in

previous lease sale EISs (BOEMRE, 2011a,b).

Impacts of Air Pollutant Emissions

Air pollutant emissions are the only routine IPF likely to affect air quality.  Offshore air pollutant

emissions will result from the drilling rig operations, helicopters, and service vessels.  These

emissions occur mainly from combustion or burning of diesel fuel.  The combustion of fuels

occurs primarily on diesel‐powered generators, pumps, or motors and from lighter fuel motors.  

Primary air pollutants typically associated with OCS activities are suspended PM, SOx, NOx, VOCs,

and CO.  Emissions of pollutants into the atmosphere from these activities are not projected to

have significant effects on onshore air quality because of the prevailing atmospheric conditions,

emission rates and heights, and resulting pollutant concentrations.  As the BOEMRE found in the

lease sale EISs, the incremental contribution of activities similar to Anadarko’s proposed

activities to the cumulative impacts is not significant and will not cause or contribute to a

violation of any National Ambient Air Quality Standard (NAAQS) (MMS, 2007b, 2008).  Since the

BOEMRE completed the lease sale EISs, the USEPA has adopted a new short‐term NAAQS for

nitrogen dioxide.  The standard has not yet been implemented in the Gulf Coast states, but

given the levels of expected emissions and the distance of the project from shore, emissions

from the activities described in Anadarko’s proposed EP are not likely to contribute to violations

of any NAAQS onshore.
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Carbon dioxide (CO2) and methane (CH4) emissions from the project would constitute a small

incremental contribution to greenhouse gas emissions from all OCS activities.  According to the

Programmatic EIS (MMS, 2007a), estimated CO2 emissions from all OCS activities in the

2007‐2012 leasing program are about 0.08% to 0.016% of the global CO2 emissions from fossil

fuel combustion.  Greenhouse gas emissions may contribute to climate change, with important

effects on temperature, rainfall, frequency of severe weather, ocean acidification, and sea level

rise (Intergovernmental Panel on Climate Change, 2007).  Greenhouse gas emissions from this

proposed project represent a negligible contribution to the total greenhouse gas emissions from

reasonably foreseeable activities in the Gulf of Mexico area and would not significantly alter any

of the climate change impacts evaluated in the lease sale EIS (MMS, 2007b) or Programmatic EIS

(MMS, 2007a).

Due to the distance from shore, routine operations in the project area are not expected to have

any impact on air quality conditions along the coast, including nonattainment areas.  As noted in

the lease sale EIS (MMS, 2007b), emissions of air pollutants from routine activities in the Central

Gulf of Mexico Planning Area are projected to have minimal impacts to onshore air quality

because of the prevailing atmospheric conditions, emission heights, emission rates, and the

distance of these emissions from the coastline.  The Air Quality Emissions Report

(see EP Section G) prepared in accordance with BOEM requirements shows that the projected

emissions are below exemption levels; therefore, according to 30 CFR 250.303, the emissions

will not significantly affect the air quality of the onshore area for any of the criteria pollutants.  

No further analysis or control measures are required.

The Breton Wilderness Area, which is part of the Breton National Wildlife Refuge (NWR), is

designated under the Clean Air Act as a Prevention of Significant Deterioration (PSD) Class I air

quality area.  The BOEM is required to notify the National Park Service (NPS) and U.S. Fish and

Wildlife Service (USFWS) if emissions from proposed projects may affect the Breton Class I area.  

Additional review and mitigation measures may be required for sources within 186 miles

(300 km) of the Breton Class I area that exceed emission limits agreed upon by the administering

agencies (NPS, 2010).  The lease area is approximately 172 miles (277 km) from the Breton

Wilderness Area, therefore, air quality impacts on the Wilderness Area are not expected.

Impacts of a Small Fuel Spill

Potential impacts of a small spill on air quality are expected to be consistent with those analyzed

and discussed in EISs prepared for recent lease sales (MMS, 2007b, 2008; BOEMRE, 2011a,b).  

The probability of a small spill would be minimized by Anadarko’s preventative measures during

routine operations, including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will reduce the potential impacts.  EP Section H includes a detailed discussion

of the spill response measures that would be employed.  Given the open ocean location of the

lease area, the extent and duration of air quality impacts from a small spill would not be

significant.

A small fuel spill would affect air quality near the spill site by introducing VOCs through

evaporation.  The ADIOS2 model (see Section A.9.2) indicates that over 90% of a small diesel

spill would be evaporated or dispersed within 24 hours.  The area of the sea surface with diesel

fuel on it would range from 0.5 to 5 ha (1.2 to 12 ac) depending on sea state and weather

conditions.
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A small fuel spill would not affect coastal air quality because the spill would not be expected to

make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential impacts of a large oil spill on air quality are expected to be consistent with those

analyzed and discussed in recent lease sale EISs (MMS, 2007b, 2008; BOEMRE, 2011a,b).

A large oil spill (WCD) could potentially affect air quality by introducing VOCs through

evaporation from the slick.  The extent and persistence of impacts would depend on the

meteorological and oceanographic conditions at the time and the effectiveness of spill response

measures.  Real‐time wind and current data from the project area would be available at the

time of a spill and would be used to assess the fate and effects of VOCs released.  Additional air

quality impacts could occur if response measures included in situ burning of the floating oil.  

Burning would generate a plume of black smoke and result in emissions of NOx, SOx, CO, and

PM, as well as greenhouse gases.  However, in situ burning would occur only after authorization

from the USEPA.

Due to the lease area location (143 miles [230 km]) from the nearest shoreline (Louisiana), most

air quality impacts would occur in offshore waters with minimal chance to affect onshore air

quality.

C.1.2 Water Quality

There are no site‐specific water quality data for the lease area.  Due to the lease location in

deep, offshore waters, water quality is expected to be good, with low levels of contaminants.  As

noted in a recent lease sale EIS (MMS, 2007b), deepwater areas in the northern Gulf of Mexico

are relatively homogeneous with respect to temperature, salinity, and oxygen.  Kennicutt (2000)

noted that the deepwater region has little evidence of contaminants in the dissolved or

particulate phases of the water column.  However, there are localized occurrences of natural

seepage of oil, gas, and brines in near‐surface sediments and up through the water column.

The lease area is located approximately 105 miles (169 km) from the Macondo spill site.  Based

on the general circulation pattern seen in the Gulf of Mexico and satellite imagery (ESRI, 2010),

the surface slick from that discharge extended over the lease area occasionally during the spill.  

As a result of this spill, water quality in the lease area would have been temporarily affected.  

Prior to the Macondo incident, water quality in deep, offshore waters of the Gulf of Mexico was

expected to be good, with low levels of contaminants (Kennicutt, 2000).  Based on the

information currently available, there is no reason to expect any long‐term change in water

quality conditions in the lease area from those predicted in the recent lease sale EISs

(MMS 2007b, 2008; BOEMRE, 2011a,b).

IPFs potentially affecting water quality are effluent discharges and two types of accidents ‐ 

a small fuel spill and a large oil spill (WCD).

Impacts of Effluent Discharges

In general, turbid water can be expected to extend between a few hundred meters and several

kilometers down current from the discharge point for water‐based drilling muds and cuttings.  

SBMs will be collected on the rig and either reused by the vendor, or transported to Port

Fourchon and onwards to the Newpark base for recycling and/or disposal in an approved
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facility.  Cuttings wetted with SBMs will be discharged to the seafloor in accordance with the

NPDES permit.  All NPDES permit limitations and requirements will be met.  There will be no

persistent impacts on water quality in the lease area (National Research Council, 1983;

Neff, 1987; Neff et al., 2000).  

Treated sanitary and domestic wastes, including those from support vessels, may have a slight

transient effect on water quality in the immediate vicinity of these discharges.  All NPDES permit

limitations and requirements and USCG regulations (as applicable) will be met, therefore, little

or no impact on water quality is anticipated.

Deck drainage includes all effluents resulting from rain, deck washings, and runoff from curbs,

gutters, and drains, including drip pans in work areas.  Rainwater that falls on uncontaminated

areas of the drilling rig will flow overboard without treatment.  However, rainwater that falls on

the drilling rig deck and other areas such as chemical storage areas and places where equipment

is exposed will be collected and oil and water separated to meet NPDES permit requirements.  

Based on adherence to permit limits and applicable regulations, little or no impact on water

quality is anticipated.

Other discharges in accordance with the NPDES permit, such as desalination unit brine and

uncontaminated cooling water, fire water, and ballast water are expected to be diluted rapidly,

resulting in little or no impact on water quality.

Impacts of a Small Fuel Spill

Potential impacts of a small spill on water quality are expected to be consistent with those

analyzed and discussed in recent EISs (MMS, 2007b, 2008; BOEMRE, 2011a,b).  The probability

of a small spill would be minimized by Anadarko’s preventative measures during routine

operations, including fuel transfer.  In the unlikely event of a spill, implementation of Anadarko’s

OSRP will potentially help mitigate and reduce the impacts.  EP Section H provides detail on spill

response measures in addition to the summary information provided in this EIA.  Given the open

ocean location of the lease area, the extent and duration of water quality impacts from a small

spill would not be significant.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  However, it is estimated that over

90% of a small diesel spill would be evaporated or dispersed within 24 hours (see Section A.9.2).  

The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha (1.2 to 12 ac)

depending on sea state and weather conditions.

The water‐soluble fractions of diesel are dominated by two‐ and three‐ringed PAHs, which are

moderately volatile (National Research Council, 2003).  The constituents of these oils are light to

intermediate in molecular weight and can be readily degraded by aerobic microbial oxidation.  

Due to its light density, diesel will not sink to the seafloor.  Diesel dispersed in the water column

can adhere to suspended sediments, but this generally occurs only in coastal areas with high

suspended solid loads (National Research Council, 2003) and would not be expected to occur to

any appreciable degree in offshore waters of the Gulf of Mexico.  Diesel oil is readily and

completely degraded by naturally occurring microbes (NOAA, 2006).
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A small fuel spill would not affect coastal water quality because the spill would not be expected

to make landfall or reach coastal waters due to both response efforts that would be undertaken

as well as natural attenuation (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential impacts of a large oil spill on water quality are expected to be consistent with those

analyzed and discussed in recent lease sale EISs (MMS, 2007b, 2008).  A large spill would affect

water quality by producing a slick on the water surface and increasing the concentrations of

petroleum hydrocarbons and their degradation products.  The extent and persistence of impacts

would depend on the meteorological and oceanographic conditions at the time and the

effectiveness of spill response measures.  Most of the oil would be expected to form a slick at

the surface, although new information from the Macondo spill indicates that plumes of

submerged oil droplets can be produced when subsea dispersants are applied at the wellhead

(Camilli et al., 2010; Hazen et al., 2010; Joint Analysis Group, 2010a,b,c).  However, dispersants

would be applied only after approval from the USEPA.  Small droplets in the water may adhere

to suspended sediment and be removed from the water column (Operational Scientific Advisory

Team [OSAT], 2010).

Due to the lease area location (143 miles or 230 km from the nearest shoreline [Louisiana]), it is

expected that most water quality impacts would occur in offshore waters, especially in the

event of a spill lasting less than 30 days (Table 3).

C.2 Seafloor Habitats and Biota

Water depths at both the proposed SHLs are approximately 2,769.71 to 2,770.32 m

(9,087 to 9,089 ft). The seafloor is slightly irregular or hummocky at the proposed site

(Map B‐2).  The irregular seafloor is the surface expression of buried turbidite and mass‐

transport deposits.  A surficial drape of high water‐content silty clays likely covers the seafloor.  

The seafloor slopes to the southeast at about 0.6° (GEMS, 2009).  Based on the absence of hard

bottom areas determined by side‐scan sonar during the Site Clearance Survey, the seafloor is

expected to consist mainly of soft bottom communities.  The Site Clearance Survey did not

identify any features that could support high‐density deepwater benthic communities within

610 m (2,000 ft) of the wellsites.  No areas of gaseous sediments or possible hydrocarbon

seepage were defined in the study area, and the presence of chemosynthetic communities is

considered low (GEMS, 2009).

C.2.1 Soft Bottom Benthic Communities

There are no site‐specific benthic community data from the lease area.  However, data from the

Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology study (Wei, 2006;

Rowe and Kennicutt, 2009) can be used to describe typical benthic communities in the area.  

Table 4 summarizes data from two nearby stations in similar water depths.  Sediments at these

two stations were predominantly clay (47.9% to 57.8%) and silt (31.8% to 38.6%).
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Table 4. Benthic community data from stations near the lease area and in similar water depths

sampled during the Northern Gulf of Mexico Continental Slope Habitats and Benthic

Ecology Study (From: Wei, 2006; Rowe and Kennicutt, 2009).

Station

Location

Relative to

Lease Area

Water

Depth

(m)

Abundance

Meiofauna

(individuals/m2)

Macroinfauna

(individuals/m2)

Megafauna

(individuals/ha)

NB3 27 mi 1,874 165,245 1,342 191

NB4 32 mi 2,042 148,409 1,443  ‐‐ 

Meiofaunal and megafaunal abundance from Rowe and Kennicutt (2009); macroinfaunal abundance from

Wei (2006).

Meiofauna (animals passing through a 0.5‐mm sieve but retained on a 0.062‐mm sieve)

densities in water depths representative of the lease area typically range from about

117,000 to 157,000 individuals/m2 (Rowe and Kennicutt, 2009).  Nematodes, nauplii, and

harpacticoid copepods were the three dominant groups in the meiofauna, accounting for about

90% of total abundance.

The benthic macroinfauna is characterized by small mean individual sizes and low densities,

both of which are a reflection of the meager primary production in Gulf of Mexico surface

waters (Wei, 2006).  Densities decrease exponentially with water depth.  Based on an equation

presented by Wei (2006), macroinfaunal densities in the water depths of the wellsites are

expected to be about to 1,380 to 1,400 individuals/m2

, or somewhat greater than the numbers

in Table 4.

Polychaetes are typically the most abundant macroinfaunal group on the northern Gulf of

Mexico continental slope, followed by amphipods, tanaids, bivalves, and isopods.  Wei (2006)

recognized four depth‐dependent faunal zones (1 through 4), two of which are divided

horizontally.  The lease area is in Zone 3W.  This zone, with stations in water depths of

1,875 m to 3,008 m (6,152 to 9,869 ft) had the polychaetes Levinsenia uncinata, Paraonella

monilaris, Tachytrypane sp. A, the bivalve Heterodonta sp., and the isopod Macrostylis “256” as

the most abundant taxa.

Megafaunal densities from the nearby station NB3 were 191 individuals/ha (Table 4).  Densities

of 252 to 1,600 individuals/ha were reported from other stations in a similar depth range.  

Common megafauna included motile groups such as decapods, ophiuroids, holothurians, and

demersal fishes as well as sessile groups such as sponges and anemones.

Bacteria are also an important component in terms of biomass and cycling of organic carbon

(Cruz‐Kaegi, 1998).  Bacterial biomass at the depth range of the lease area typically is about

1 to 2 g C/m2 in the top 15 cm of sediments (Rowe and Kennicutt, 2009).

Physical Disturbance to the Seafloor

In water depths such as are encountered in the lease area, DP drillships or DP semisubmersibles

disturb the seafloor only around the wellbore (SHL) where the bottom template and blowout

preventer are located.  Depending upon the specific well configuration, this area is generally

about 0.25 ha (0.62 ac).  The areal extent of these impacts from both DP rigs will be small

compared to the lease area itself, and these type soft bottom communities are ubiquitous along

the northern Gulf of Mexico continental slope (Gallaway, 1988; Gallaway et al., 2003; Rowe and
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Kennicutt, 2009).  Impacts from the physical disturbance of the seafloor during this project will

have no significant impact on soft bottom benthic communities in the region.

Impacts of Effluent Discharges

Drilling muds and cuttings are the only effluents that are likely to affect benthic communities.  

During initial well interval(s) before the marine riser is set, cuttings and seawater‐based “spud

mud” will be released at the seafloor.  Excess cement slurry will also be released at the seafloor

during casing installation for the riserless portion of the drilling operations.  Cement slurry

components typically include cement mix and some of the same chemicals used in water‐based

drilling muds (Boehm et al., 2001).  The main impacts will be burial and smothering of benthic

organisms within several meters to tens of meters around the wellbore.  Soft bottom sediments

disturbed by cuttings, drilling muds, and cement slurry will eventually be recolonized through

larval settlement and migration from adjacent areas.  Because some deep‐sea biota grow and

reproduce slowly, recovery may require several years.

Discharges of washed SBM cuttings from the rig may affect benthic communities, primarily

within several hundred meters of the wellsite.  The fate and effects of SBM cuttings have been

reviewed by Neff et al. (2000), and monitoring studies have been conducted in the Gulf of

Mexico by Continental Shelf Associates, Inc. (2004, 2006).  In general, washed cuttings with

adhering SBMs tend to clump together and form thick cuttings piles close to the drillsite.  Areas

of SBM cuttings deposition may develop elevated organic carbon concentrations and anoxic

conditions (Continental Shelf Associates, Inc., 2006).  Where SBM cuttings accumulate in

concentrations of approximately 1,000 mg/kg or higher, benthic infaunal communities may be

adversely affected due to both the toxicity of the base fluid and organic enrichment

(with resulting anoxia) (Neff et al., 2000).  Infaunal numbers may increase and diversity may

decrease as opportunistic species that tolerate low oxygen and high H2S predominate

(Continental Shelf Associates, Inc., 2006).  As the base synthetic fluid is decomposed by

microbes, the area will gradually return to pre‐drilling conditions.  Disturbed sediments will be

recolonized through larval settlement and migration from adjacent areas.

The areal extent of impacts from drilling discharges will be small.  Assuming a typical effect

radius of 500 m (1,640 ft), the affected area around each wellsite would represent about 3% of

the seafloor within a lease block.  Soft bottom communities are ubiquitous along the northern

Gulf of Mexico continental slope (Gallaway, 1988; Gallaway et al., 2003; Rowe and

Kennicutt, 2009).  Impacts from drilling discharges during this project will have no significant

impact on soft bottom benthic communities in the region.

Impacts of a Large Oil Spill (WCD)

The most likely effects of a subsea blowout on benthic communities would be within a few

hundred meters of the wellsite.  The MMS (2007b) estimated that a severe subsurface blowout

could resuspend and disperse sediments within a 300‐m (984‐ft) radius.  While coarse sediments

(sands) would probably settle at a rapid rate within 400 m (1,312 ft) from the blowout site, fine

sediments (silts and clays) could be resuspended for more than 30 days and dispersed over a

much wider area.  Based on previous studies, surface sediments at the project area are assumed

to largely be silt and clay (Rowe and Kennicutt, 2009).
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Recent lease sale EISs (MMS, 2007a, 2008) indicated that oil spills would be unlikely to affect

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill

location.  However, during the Macondo spill, subsurface plumes were reported at a water

depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsite and

persisting for more than a month (Camilli et al., 2010).  The subsurface plumes apparently

resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c).  While the

behavior and impacts of subsurface plumes are not well known, a subsurface plume could

contact the seafloor and affect benthic communities beyond the 300‐m (984‐ft) radius

estimated by MMS (2007a, 2008), depending on its extent, trajectory, and persistence.  This

contact could result in smothering and/or toxicity to benthic organisms.  The affected area

would be recolonized by benthic organisms over a period of months to years (National Research

Council, 2003).

C.2.2 High‐Density Deepwater Benthic Communities

As defined by NTL 2009‐G40, high‐density deepwater benthic communities are features or areas

that could support high‐density chemosynthetic communities, or features or areas that could

support high‐density deepwater corals and other associated high‐density hard bottom

communities.  Chemosynthetic communities were discovered in the central Gulf of Mexico in

1984 and have been studied extensively (MacDonald, 2002).  Deepwater coral communities are

also known from numerous locations in the Gulf of Mexico (Brooke and Schroeder, 2007;

CSA International, Inc., 2007).  These communities occur almost exclusively on authigenic

carbonates created by chemosynthetic communities.

The nearest known chemosynthetic community and the nearest identified deepwater coral

community are both located in Viosca Knoll Block 826, approximately 128 miles (206 km)

north‐northwest of the lease area.

There are no features or areas that could support significant deepwater benthic communities

within a 2,000‐ft radius around the proposed wellsites.  Therefore, the potential for high‐density

chemosynthetic communities within 2,000 ft of the proposed locations is considered low

(GEMS, 2009).

IPFs potentially affecting high‐density deepwater benthic communities include physical

disturbance of the seafloor, effluent discharges (drilling muds and cuttings), and a large oil spill

(WCD) from a well blowout at the seafloor.  A small fuel spill would not affect benthic

communities because the diesel fuel would float and dissipate on the sea surface.

Physical Disturbance to the Seafloor

In water depths such as are encountered in the lease area, DP drillships or DP semisubmersibles

disturb the seafloor only around the wellbore (SHL) where the bottom template and blowout

preventer are located.  Depending upon the specific well configuration, this area is generally

about 0.25 ha (0.62 ac).

The areal extent of the impacts from a DP rig will be small, and NTL 2009‐G40 requires that

high‐density deepwater benthic communities and features or areas that could support

high‐density chemosynthetic communities or deepwater corals communities be avoided.  
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Impacts from the physical disturbance of the seafloor during this project should have no impact

on chemosynthetic or deepwater coral communities in the region.

Impacts of Effluent Discharges

The Site Clearance Survey (GEMS, 2009) did not identify any features that could support

high‐density deepwater benthic communities within 610 m (2,000 ft) of the proposed drilling

locations, and the presence of chemosynthetic communities in the lease area is considered low.  

Monitoring programs on the Gulf of Mexico continental slope have shown that benthic impacts

from drilling discharges typically are concentrated within about 500 m (1,640 ft) of the wellsite,

although detectable deposits may extend beyond this distance (Continental Shelf Associates,

Inc., 2004, 2006; Neff et al., 2005).  Because of the water depth of the lease area, drilling

discharges would be expected to result in thinner, more diffuse accumulations on the seafloor

than those documented in the literature.  Although small amounts of cuttings particles may

reach areas inhabited by high‐density deepwater benthic communities, the discharges are not

expected to result in significant impacts to these communities.

Impacts of a Large Oil Spill (WCD)

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill

location.  However, during the Macondo spill, subsurface plumes were reported at a water

depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsite and

persisting for more than a month (Camilli et al., 2010).  The subsurface plumes apparently

resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c).  While the

behavior and impacts of subsurface plumes are not well known, a subsurface plume could have

the potential to contact high‐density deepwater benthic communities beyond the 300‐m

(984‐ft) radius estimated by MMS (2007a, 2008), depending on its extent, trajectory, and

persistence.  Potential impacts on sensitive resources would be an integral part of the decision

and approval process for the use of dispersants, and such approval would be obtained from the

USEPA prior to the use of dispersants.

The biological effects and expected fate of the oil remaining in the Gulf of Mexico from the

blowout are still unknown due to the depth and magnitude of this event.  Hazen et al. (2010)

reported changes in plume hydrocarbon composition with distance from the source.  Incubation

experiments with environmental isolates demonstrated faster than expected hydrocarbon

biodegradation rates at 5°C.  Based on these results, Hazen et al. (2010) suggested the potential

exists for intrinsic bioremediation of the oil plume in the deep‐water column without substantial

oxygen drawdown.

Potential impacts of oil on high‐density deepwater benthic communities are discussed in

MMS (2007b).  Although chemosynthetic communities live among hydrocarbon seeps, natural

seepage is very constant and occurs at low rates compared to the potential rates of oil release

from a blowout.  In addition, seep organisms also require unrestricted access to oxygenated

water at the same time as exposure to hydrocarbon energy sources (MacDonald, 2002).  Oil

droplets or oiled sediment particles could come into contact with chemosynthetic organisms or

deepwater corals.  As discussed by MMS (2007b), impacts could include loss of habitat,

biodiversity, and live coral coverage; destruction of hard substrate; change in sediment

characteristics; and reduction or loss of one or more commercial and recreational fishery
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habitats.  Sublethal effects could be long‐lasting and affect the resilience of coral colonies to

natural disturbances (e.g., elevated water temperature and diseases).

The potential for a spill to affect deepwater corals is indicated by preliminary findings from a

recent (October 2010) survey of deepwater coral habitats near the Macondo spill site

(BOEMRE, 2010).  Government and academic researchers were working at a site 1,400 m

(4,600 ft) deep and approximately 7 miles (11 km) southwest of the Macondo wellhead when

they observed dead and dying corals with sloughing tissue and discoloration.  Much of the soft

coral observed in an area measuring about 15 to 40 m (50 to 130 ft) was covered by what

appeared to be a brown substance.  Out of 40 large corals, 90% were heavily affected and

showed dead and dying parts and discoloration.  Another site 400 m (1,312 ft) farther away had

a colony of stony corals similarly affected and partially covered with a similar brown substance.  

Until laboratory analyses are conducted, scientists cannot be certain what caused the impacts.  

Sediment and coral samples were collected with a remotely operated vehicle and brought to the

surface for analyses.  Further testing will also determine if the substance is oil, and if so,

whether it is consistent with the release from the Macondo spill.

C.2.3 Designated Topographic Features

The block is not within or near a designated topographic feature or a no‐activity zone as

identified in NTL 2009‐G39.  The nearest designated topographic feature is in the West Delta

Area, South Addition, Block 147, located 141 miles (226 km) west of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to designated topographic features due to the distance from the lease area.  A small

fuel spill would float and dissipate on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf edge.

C.2.4 Pinnacle Trend Area Live Bottoms

The lease area is not covered by the Live Bottom (Pinnacle Trend) Stipulation.  As defined by

NTL 2009‐G39, the nearest pinnacle trend is Viosca Knoll Block 778, which lies 131 miles

(210 km) north‐northwest of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to pinnacle trend area live bottoms due to the distance from the lease area.  A small

fuel spill would float on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf edge.
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C.2.5 Live Bottom/Low Relief

The lease area is not covered by the Live Bottom (Low‐Relief) Stipulation, which applies to

Eastern Gulf of Mexico Planning Area leases in water depths of 100 m (328 ft) or less.  The

nearest block covered by the live bottom stipulation, as defined by NTL 2009‐G39, is

Destin Dome Block 573, approximately 140 miles (225 km) north‐northeast of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to live bottom areas due to the distance from the lease area.  A small fuel spill would

float and dissipate on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features.  If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth.  Near‐bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf.

C.3 Threatened, Endangered, and Protected Species and Critical Habitat

This section discusses species listed as endangered or threatened under the Endangered Species

Act (ESA).  In addition, it includes all marine mammal species in the region, which are protected

under the Marine Mammal Protection Act (MMPA).

Endangered or threatened species that may occur in the project area and/or along the northern

Gulf Coast are listed in Table 5.  The table also indicates the location of critical habitat

(if designated in the Gulf of Mexico).  Critical habitat is defined as (1) specific areas within the

geographical area occupied by the species at the time of listing, if they contain physical or

biological features essential to conservation, and those features may require special

management considerations or protection; and (2) specific areas outside the geographical area

occupied by the species if the agency determines that the area itself is essential for

conservation.  The National Marine Fisheries Service (NMFS) has jurisdiction for ESA‐listed

cetaceans, sea turtles, and fishes in the Gulf of Mexico.  The USFWS has jurisdiction for

ESA‐listed birds and the West Indian manatee.

As mandated by the ESA, BOEMRE consulted NMFS and the USFWS on possible and potential

impacts from the proposed leasing in the Gulf of Mexico on endangered/threatened species and

their designated critical habitat (MMS, 2007a,b).  A Biological Assessment was prepared for each

consultation.  The formal ESA consultation with NMFS was concluded with receipt of the

Biological Opinion on 3 July 2007 (NMFS, 2007).  The Biological Opinion concludes that the

proposed lease sales and associated activities in the Five‐Year Leasing Plan for Western and

Central Planning Areas 2007‐2012 are not likely to jeopardize the continued existence of

threatened and endangered species under NMFS jurisdiction or destroy or adversely modify

designated critical habitat.  The informal ESA consultation with USFWS was concluded with a

letter dated 14 September 2007.  The USFWS concurred with MMS’s determination that

proposed actions of the current Five‐Year Leasing Plan were not likely to adversely affect

threatened/endangered species or designated critical habitat under USFWS jurisdiction.  

Following the Macondo spill, BOEMRE requested to reinitiate an ESA consultation with both

NMFS and USFWS on 30 July 2010.  The NMFS responded with a letter to BOEMRE on

24 September 2010, and the USFWS responded with a letter to BOEMRE on 27 September 2010.  
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Environmental Impact Analysis for Initial Exploration Plan Page 30

At present, the NMFS and USFWS have placed the consultation process on hold because they

feel the environmental baseline information needs to be updated for the post‐Macondo spill

environment based on the results of the Natural Resource Damage Assessment (NRDA) process.  

The NRDA data have yet to be released, and the existing consultation remains in effect

(BOEMRE, 2011a).  The existing consultation recognizes that BOEMRE‐required mitigations and

other reasonable and prudent measures should reduce the likelihood of impacts from all

BOEMRE‐authorized activities in the Gulf of Mexico.

Coastal endangered or threatened species that may occur along the northern Gulf Coast include

the West Indian manatee, Piping Plover, Whooping Crane, Gulf sturgeon, and four subspecies of

beach mice.  Critical habitat has been designated for all of these species as indicated in Table 5

and discussed in individual sections.

Table 5. Federally‐listed endangered and threatened species potentially occurring in the lease

area and along the northern Gulf Coast.

Species Scientific Name Status

Potential Presence Critical Habitat

Designated in

Gulf of Mexico

Lease

Area Coastal

Marine Mammals

Sperm whale Physeter macrocephalus E X ‐‐ None

West Indian manatee Trichechus manatus latirostris E ‐‐ X Florida (Peninsular)

Blue whale Balaenoptera musculus E Xa ‐‐ None

Fin whale Balaenoptera physalus E Xa ‐‐ None

Humpback whale Megaptera novaeangliae E Xa ‐‐ None

North Atlantic right whale Eubalaena glacialis E Xa ‐‐ None

Sei whale Balaenoptera borealis E Xa ‐‐ None

Sea Turtles

Loggerhead turtle Caretta caretta T X X None

Green turtle Chelonia mydas T, E

b X X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempii E X X None

Birds

Piping Plover Charadrius melodus T  ‐‐  X

Coastal Texas, Louisiana,

Mississippi, Alabama,

and Florida (Panhandle)

Whooping Crane Grus americana E  ‐‐  X

Coastal Texas

(Aransas National

Wildlife Refuge)

Fishes

Gulf sturgeon Acipenser oxyrinchus desotoi T  ‐‐  X

Coastal Louisiana,

Mississippi, Alabama,

and Florida (Panhandle)

Smalltooth sawfish Pristis pectinata E  ‐‐  X Southwest Florida and

the Florida Keys

Invertebrates

Elkhorn coral Acropora palmata E ‐‐ X Flower Garden Banks

Terrestrial Mammals

Beach mice (Alabama,

Choctawhatchee,

Perdido Key, St. Andrew)

Peromyscus polionotus E  ‐‐  X Alabama and Florida

(Panhandle) beaches

Abbreviations: E = endangered; T = threatened.   a

   The blue, fin, humpback, North Atlantic right, and sei whales are rare or extralimital in the Gulf of Mexico and are unlikely

to be present in the lease area. b

   The green sea turtle is threatened, except for the Florida breeding population, which is listed as endangered.
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Two other coastal species (Bald Eagle and Brown Pelican) are discussed in the MMS (2007b)

lease sale EIS are no longer listed as endangered or threatened.  These species are discussed

here under Coastal and Marine Birds.

The sperm whale and five species of sea turtles are the only endangered or threatened species

likely to occur at or near the lease area.  No critical habitat has been designated for these

species in the Gulf of Mexico.

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare

or extralimital there (Würsig et al., 2000).  No critical habitat has been designated for these

species in the Gulf of Mexico.

C.3.1 Sperm Whale (Endangered)

The only endangered marine mammal likely to be present at or near the project area is the

sperm whale (Physeter macrocephalus).  Resident populations of sperm whales occur within the

Gulf of Mexico.  A species description is presented in a recent lease sale EIS (MMS, 2007b).  Gulf

of Mexico sperm whales are classified as an endangered species and a “strategic stock” (defined

as a stock that may have unsustainable human‐caused impacts) by NOAA Fisheries (Waring

et al., 2009).  No critical habitat for the sperm whale has been designated in the Gulf of Mexico.

The distribution of sperm whales in the Gulf of Mexico is correlated with mesoscale physical

features such as eddies associated with the Gulf of Mexico Loop Current (Jochens et al., 2008).  

Sperm whale populations in the north‐central Gulf of Mexico are present there throughout the

year (Davis et al., 2000).  Results of a multi‐year tracking study show female sperm whales

typically concentrated along the upper continental slope between the 200‐ and 1,000‐m

(656‐ and 3,280‐ft) depth contours (Jochens et al., 2008).  Male sperm whales were more

variable in their movements and were documented in water depths greater than 3,000 m

(9,843 ft).  Generally, groups of sperm whales sighted in the Gulf of Mexico during the

MMS‐funded Sperm Whale Seismic Study (SWSS) consisted of mixed‐sex groups comprising

adult females and immatures, and groups of bachelor males.  Typical group size for mixed

groups was 10 individuals (Jochens et al., 2008).  SWSS results show that sperm whales transit

through the vicinity of the lease area.  Movements of satellite‐tracked individuals suggest that

this area of the Gulf continental slope is within the home range of the Gulf of Mexico population

(within the 95% utilization distribution) (Jochens et al., 2008).

IPFs potentially affecting sperm whales include drilling rig presence, noise, and lights; support

vessel and helicopter traffic; and two types of accidents – a small fuel spill and a large oil spill

(WCD).  Effluent discharges are likely to have negligible impacts on sperm whales due to rapid

dispersion, the small area of ocean affected, the intermittent nature of the discharges, and the

mobility of these marine mammals.  Compliance with BSEE NTL 2012‐G01 will minimize the

potential for marine debris‐related impacts on sperm whales.

Current threats to sperm whale populations worldwide are discussed in a final recovery plan for

the sperm whale recently published by NOAA (NMFS, 2010a).  Threats are defined as “any factor

that could represent an impediment to recovery,” and include fisheries interactions,

anthropogenic noise, vessel interactions, contaminants and pollutants, disease, injury from

marine debris, research, predation and natural mortality, direct harvest, competition for

resources, loss of prey base due to climate change and ecosystem change, and cable laying.  In
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Environmental Impact Analysis for Initial Exploration Plan Page 32

the Gulf of Mexico, the impacts from many of these threats are identified as either low or

unknown (BOEMRE, 2011a,b).

Impacts of Drilling Rig Presence, Noise, and Lights

Noise from routine drilling activities has the potential to disturb sperm whales.  Sperm whales

appear to have good mid‐frequency hearing, but the available data do not indicate a consistent

response to anthropogenic noise (Southall et al., 2007).  Noise intensity associated with drilling

is relatively weak, and the noise exposure of an individual animal would be transient.  There are

other OCS facilities and activities near the lease area, and the region as a whole has a large

number of similar noise sources.  Due to the limited scope and short duration of drilling

activities, this project would represent a small temporary contribution to the overall noise

regime.

NMFS analyzed the potential for impacts of drilling‐related noise on sperm whales in its

Biological Opinion for the Gulf of Mexico Oil and Gas Activities: Five‐Year Leasing Plan for

Western and Central Planning Areas 2007‐2012 (NMFS, 2007).  The analysis noted that

semisubmersible drilling rigs emit low sound source levels and concluded that drilling is not

expected to produce amplitudes sufficient to cause hearing or behavioral effects in sperm

whales; therefore, these effects are insignificant (NMFS, 2007).

Drilling rig lighting and rig presence are not identified as IPFs for sperm whales in recent lease

sale EISs (MMS, 2007b, 2008) or the NMFS (2007) Biological Opinion.

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sperm whales, and there is also a risk of vessel

strikes, which are identified as a threat in the recovery plan for this species (NMFS, 2010a).  Data

concerning the frequency of vessel strikes are presented in a recent lease sale EIS

(MMS, 2007b).  To reduce the potential for vessel strikes, BOEM/BSEE issued Joint

NTL 2012‐G01, which recommends protected species identification training and that vessel

operators and crews maintain a vigilant watch for marine mammals and slow down or stop their

vessel to avoid striking protected species, and requires operators to report sightings of any

injured or dead protected species.  When whales are sighted, vessel operators and crews are

required to attempt to maintain a distance of 91 m (300 ft) or greater whenever possible.  

Vessel operators are required to reduce vessel speed to 10 knots or less when mother/calf pairs,

pods, or large assemblages of cetaceans are observed near an underway vessel, when safety

permits.  Compliance with this NTL will minimize the likelihood of vessel strikes as well as reduce

the chance for disturbing sperm whales.

NMFS (2007) analyzed the potential for vessel strikes and harassment of sperm whales.  With

implementation of the mitigation measures in Joint NTL 2012‐G01, NMFS concluded that the

likelihood of collisions between vessels and sperm whales would be reduced to insignificant

levels.  NMFS concluded that the observed avoidance of passing vessels by sperm whales is an

advantageous response to avoid a potential threat and is not expected to result in any

significant effect on migration, breathing, nursing, breeding, feeding, or sheltering to individuals,

or have any consequences at the level of the population.  With implementation of the vessel

strike avoidance measures requirement to maintain a distance of 90 m (295 ft) from sperm

whales, the NMFS concluded that the potential for harassment of sperm whales would be

reduced to discountable levels.
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Helicopter traffic also has the potential to disturb sperm whales.  Smultea et al. (2008)

documented responses of sperm whales offshore Hawaii to fixed wing aircraft flying at an

altitude of 245 m (800 ft).  A reaction to the initial pass of the aircraft was observed during

3 (12%) of 24 sightings.  All three reactions consisted of a hasty dive and occurred at less than

360 m (1,180 ft) lateral distance from the aircraft.  Additional reactions were seen when aircraft

circled certain whales to make further observations.  Based on other studies of cetacean

responses to sound, the authors concluded that the observed reactions to brief overflights by

the aircraft were short‐term and probably of no long‐term biological significance.

While flying offshore in the Gulf of Mexico, helicopters maintain altitudes above 213 m (700 ft)

during transit to and from the working area.  In the event that a whale is seen during transit, the

helicopter will not approach or circle the animals.  Although responses are possible (Smultea

et al., 2008), the NMFS (2007) concluded that this altitude would minimize the potential for

disturbing sperm whales.  Therefore, no significant impacts are expected.

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals including sperm whales are discussed in recent lease

sale EISs (MMS, 2007b, 2008) and by NMFS (2007).  Oil impacts on marine mammals are

discussed by Geraci and St. Aubin (1990).  For this EP, there are no unique site‐specific issues

with respect to spill impacts on these animals that were not analyzed in the previous

documents.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will mitigate and lessen the potential for impacts on sperm whales.  Given the

open ocean location of the lease area, the duration of a small spill and opportunity for impacts

to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (Marine Mammal Commission [MMC], 2011).  However,

due to the limited areal extent and short duration of water quality impacts from a small fuel

spill, as well as the mobility of sperm whales, no significant impacts would be expected.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine mammals including sperm whales are discussed in recent EISs

(MMS, 2007b, 2008) and by NMFS (2007).  For this EP, there are no unique site‐specific issues

with respect to spill impacts on these animals.
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Impacts of oil spills on sperm whales can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants) (MMC, 2010).  Direct physical and physiological effects can include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey; and stress from

the activities and noise of response vessels and aircraft.  Complications of the above may lead to

dysfunction of immune and reproductive systems, physiological stress, declining physical

condition, and death.  Behavioral responses can include displacement of animals from prime

habitat, disruption of social structure, changing prey availability and foraging distribution and/or

patterns, changing reproductive behavior/productivity, and changing movement patterns or

migration (MMC, 2010).

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb sperm whales and potentially result in vessel strikes, entanglement, or other injury

or stress.  Response vessels would operate in accordance with Joint NTL 2012‐G01 to reduce the

potential for striking or disturbing these animals.

C.3.2 West Indian Manatee (Endangered)

Most of the manatee population is located in peninsular Florida (USFWS, 2001).  Manatee

sightings in Louisiana have increased as the species extends its presence farther west of Florida

in the warmer months (Wilson, 2003).  A species description is presented in a recent lease sale

EIS (MMS, 2007b) and in the recovery plan for this species (USFWS, 2001).

IPFs potentially affecting manatees include support vessel and helicopter traffic and a large oil

spill (WCD).  A small fuel spill in the lease area would be unlikely to affect manatees, as the lease

area is approximately 143 miles (230 km) from the nearest shoreline (Louisiana).  As explained in

Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up.  Compliance with BSEE NTL 2012‐G01 will minimize the potential for

marine debris‐related impacts on manatees.

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb manatees, and there is also a risk of vessel

strikes, which are identified as a threat in the recovery plan for this species (USFWS, 2001).  To

reduce the potential for vessel strikes, BOEM/BSEE issued Joint NTL 2012‐G01, which

recommends protected species identification training and that vessel operators and crews

maintain a vigilant watch for marine mammals and slow down or stop their vessel to avoid

striking protected species, and requires operators to report sightings of any injured or dead

protected species.  Compliance with this NTL will minimize the likelihood of vessel strikes, and

no significant impacts on manatees are expected.

Helicopter traffic also has the potential to disturb manatees.  Rathbun (1988) reported that

manatees were disturbed more by helicopters than by fixed‐wing aircraft; however, the

helicopter was flown at a relatively low altitude of 20 to 160 m (66 to 525 ft).  Helicopters used

in support operations maintain a minimum altitude of 213 m (700 ft) while in transit offshore,

305 m (1,000 ft) over unpopulated areas or across coastlines, and 610 m (2,000 ft) over

populated areas and sensitive habitats such as wildlife refuges and park properties.  This

mitigation measure will minimize the potential for disturbing manatees, and no significant

impacts are expected.
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Environmental Impact Analysis for Initial Exploration Plan Page 35

Impacts of a Large Oil Spill (WCD)

In the event that manatees were exposed to oil, effects could include direct impacts from oil

exposure, as well as indirect impacts due to response activities and materials (e.g., vessel traffic,

noise, and dispersants) (MMC, 2010).  Direct physical and physiological effects can include skin

irritation, inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes;

inhalation of toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey

(or contaminated vegetation, in the case of manatees); and stress from the activities and noise

of response vessels and aircraft.  Complications of the above may lead to dysfunction of immune

and reproductive systems, physiological stress, declining physical condition, and death.  

Behavioral responses can include displacement of animals from prime habitat, disruption of

social structure, changing prey availability and foraging distribution and/or patterns, changing

reproductive behavior/productivity, and changing movement patterns or migration

(MMC, 2010).

In the event that a large spill reached coastal waters where manatees were present, the level of

vessel and aircraft activity associated with spill response could disturb manatees and potentially

result in vessel strikes, entanglement, or other injury or stress.  Response vessels would operate

in accordance with Joint NTL 2012‐G01 to reduce the potential for striking or disturbing these

animals, and therefore no significant impacts are expected.

C.3.3 Endangered Mysticete Whales

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare

or extralimital there (Würsig et al., 2000).  No critical habitat has been designated for these

species in the Gulf of Mexico.

Due to the rare occurrence of these whales in the Gulf of Mexico and the limited scope and

duration of the project, it is highly unlikely that any endangered mysticete would come into

contact with any project activities, either routine operations or accidents.  NMFS did not include

any of these mysticete whales as affected species in its Biological Opinion (NMFS, 2007).  

Potential impacts are analyzed in recent lease sale EISs (MMS, 2007b, 2008), and those analyses

are incorporated by reference.  If any of these whales were present in the area, potential

impacts would be the same as those discussed below in Section C.3.4.

C.3.4 Non‐Endangered Marine Mammals (Protected)

Excluding the seven endangered species that have been cited previously, there are 22 additional

species of marine mammals that may be found in the Gulf of Mexico.  This includes two

mysticete whales, the dwarf and pygmy sperm whales, 4 species of beaked whales, and

14 species of delphinids.  All marine mammals are protected species under the MMPA.  The

most common non‐endangered cetaceans in the deepwater environment are odontocetes such

as the pantropical spotted dolphin, spinner dolphin, and clymene dolphin.  A brief summary is

presented below, and additional information on these groups is presented in a recent lease sale

EIS (MMS, 2007b).

Mysticete whales.  Two non‐endangered mysticete whales are known from the Gulf of Mexico.  

The Bryde’s whale (Balaenoptera edeni) has been sighted most frequently along the 100‐m

(328‐ft) isobath (Davis and Fargion, 1996; Davis et al., 2000).  Most sightings have been made in
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Environmental Impact Analysis for Initial Exploration Plan Page 36

the DeSoto Canyon region and off western Florida, although there have been some in the

west‐central portion of the northeastern Gulf.  The minke whale (Balaenoptera acutorostrata) is

considered rare in the Gulf of Mexico, with the only confirmed records coming from strandings

(Würsig et al., 2000).  Based on the available data, it is possible that Bryde’s whales could occur

in the lease area.

Dwarf and pygmy sperm whales.  At sea, it is difficult to differentiate dwarf sperm whales

(Kogia sima) from pygmy sperm whales (Kogia breviceps), and sightings are often grouped

together as Kogia spp.  Both species have a worldwide distribution in temperate to tropical

waters.  In the Gulf of Mexico, both species occur primarily along the continental shelf edge and

in deeper waters off the continental shelf (Mullin et al., 1991).  Either species could occur in the

lease area.

Beaked whales.  Four species of beaked whales are known from the Gulf of Mexico.  They are

Blainville’s beaked whale (Mesoplodon densirostris), Cuvier’s beaked whale (Ziphius cavirostris),

Sowerby’s beaked whale (Mesoplodon bidens), and Gervais’ beaked whale (Mesoplodon

europaeus).  Stranding records in the Gulf of Mexico suggest that Gervais’ beaked whale is the

most common and Sowerby’s is extralimital.  Due to the difficulties of at‐sea identification,

beaked whales in the Gulf of Mexico are identified either as Cuvier’s beaked whales or are

grouped into an undifferentiated complex (Mesoplodon spp. and Ziphius spp.).  In the northern

Gulf of Mexico, they are broadly distributed in water depths greater than 1,000 m (3,281 ft) over

lower slope and abyssal landscapes (Davis et al., 2000).  Any of these species could occur in the

lease area.

Delphinids.  Fourteen species of delphinids are known from the Gulf of Mexico, including

Atlantic spotted dolphin (Stenella frontalis), bottlenose dolphin (Tursiops truncatus), clymene

dolphin (Stenella clymene), false killer whale (Pseudorca crassidens), Fraser’s dolphin

(Lagenodelphis hosei), killer whale (Orcinus orca), melon‐headed whale (Peponocephala electra),

pantropical spotted dolphin (Stenella attenuata), pygmy killer whale (Feresa attenuata),

short‐finned pilot whale (Globicephala macrorhynchus), Risso’s dolphin (Grampus griseus),

rough‐toothed dolphin (Steno bredanensis), spinner dolphin (Stenella longirostris), and striped

dolphin (Stenella coeruleoalba).  Any of these species could occur in the lease area.  The most

common non‐endangered cetaceans in the deepwater environment are the pantropical spotted

dolphin, spinner dolphin, and clymene dolphin.

IPFs potentially affecting non‐endangered marine mammals include drilling rig presence, noise,

and lights; support vessel and helicopter traffic; and two types of accidents ‐ a small fuel spill

and a large oil spill (WCD).  Effluent discharges are likely to have negligible impacts on marine

mammals due to rapid dispersion, the small area of ocean affected, the intermittent nature of

the discharges, and the mobility of marine mammals.  Compliance with BSEE NTL 2012‐G01 will

minimize the potential for marine debris‐related impacts on marine mammals.

Impacts of Drilling Rig Presence, Noise, and Lights

Noise from routine drilling activities has the potential to disturb marine mammals.  Most

odontocetes (toothed whales and dolphins) use higher frequency sounds than the dominant low

frequencies produced by OCS drilling activities (Richardson et al., 1995).  Noise intensity

associated with drilling is relatively weak, and the noise exposure of an individual animal would

be transient.  There are other OCS facilities and activities near the lease area, and the region as a
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Environmental Impact Analysis for Initial Exploration Plan Page 37

whole has a large number of similar sources.  Due to the limited scope and short duration of

drilling activities, this project would represent a small temporary contribution to the overall

noise regime, and any short‐term impacts are not expected to be biologically significant to

marine mammal populations.

Drilling rig lighting and rig presence are not identified as IPFs for marine mammals in recent

lease sale EISs (MMS, 2007b, 2008).

Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb marine mammals, and there is also a risk of

vessel strikes.  Data concerning the frequency of vessel strikes are presented in a recent lease

sale EIS (MMS, 2007b).  To reduce the potential for vessel strikes, BOEM/BSEE issued Joint

NTL 2012‐G01, which recommends protected species identification training and that vessel

operators and crews maintain a vigilant watch for marine mammals and slow down or stop their

vessel to avoid striking protected species, and requires operators to report sightings of any

injured or dead protected species.  Vessel operators and crews are required to attempt to

maintain a distance of 91 m (300 ft) or greater when whales are sighted and 45 m (150 ft) when

small cetaceans are sighted.  When cetaceans are sighted while a vessel is underway, vessels

must attempt to remain parallel to the animal’s course and avoid excessive speed or abrupt

changes in direction until the cetacean has left the area.  Vessel operators are required to

reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large assemblages of

cetaceans are observed near an underway vessel, when safety permits.  Compliance with Joint

NTL 2012‐G01 will minimize the likelihood of vessel strikes as well as reduce the chance for

disturbing marine mammals, and therefore no significant impacts are expected.

Aircraft traffic also has the potential to disturb marine mammals (Würsig et al., 1998).  However,

while flying offshore, helicopters maintain altitudes above 213 m (700 ft) during transit to and

from the working area.  This altitude will minimize the potential for disturbing marine mammals,

and no significant impacts are expected (MMS, 2007b).

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b, 2008),

and oil impacts on marine mammals in general are discussed by Geraci and St. Aubin (1990).  For

this EP, there are no unique site‐specific issues with respect to spill impacts on these animals.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during fuel

transfer.  In the unlikely event of a spill, implementation of Anadarko’s OSRP is expected to

lessen the potential for impacts on marine mammals.  EP Section H provides detail on spill

response measures, along with a summary of those measures in this EIA.  Given the open ocean

location of the lease area, the limited duration of a small spill and response efforts, it is

expected that any impacts would be brief and minimal.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally
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within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (MMC, 2010).  However, due to the limited areal extent

and short duration of water quality impacts from a small fuel spill, as well as the mobility of

marine mammals, no significant impacts would be expected.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine mammals are discussed in MMS (2000, 2007b, 2008).  For this

EP, there are no unique site‐specific issues.  Impacts of oil spills on marine mammals can include

direct impacts from oil exposure, as well as indirect impacts due to response activities and

materials (e.g., vessel traffic, noise, and dispersants) (MMC, 2010).  Direct physical and

physiological effects can include skin irritation, inflammation, or necrosis; chemical burns of

skin, eyes, and mucous membranes; inhalation of toxic fumes; ingestion of oil (and dispersants)

directly or via contaminated prey (or contaminated vegetation, in the case of manatees); and

stress from the activities and noise of response vessels and aircraft.  Complications of the above

may lead to dysfunction of immune and reproductive systems, physiological stress, declining

physical condition, and death.  Behavioral responses can include displacement of animals from

prime habitat, disruption of social structure, changing prey availability and foraging distribution

and/or patterns, changing reproductive behavior/productivity, and changing movement

patterns or migration (MMC, 2010).

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb marine mammals and potentially result in vessel strikes, entanglement, or other

injury or stress.  Response vessels would operate in accordance with Joint NTL 2012‐G01 to

reduce the potential for striking or disturbing these animals, and therefore no significant

impacts are expected.

C.3.5 Sea Turtles (Endangered/Threatened)

Five species of endangered or threatened sea turtles may be found near the lease area.  

Leatherback (Dermochelys coriacea), Kemp's ridley (Lepidochelys kempii), and hawksbill

(Eretmochelys imbricata) turtles are endangered.  The loggerhead turtle (Caretta caretta) is a

threatened species; however, in March 2010, NMFS and USFWS proposed to list the Northwest

Atlantic Ocean population of loggerhead turtles as endangered (75 FR12598).  The green turtle

(Chelonia mydas) is listed as threatened, except for the Florida and Pacific Coast of Mexico

breeding populations, which are listed as endangered.  Species descriptions are presented in

MMS (2007b).

The extent and scope of the Macondo spill represents new information not assessed in the

existing ESA Section 7 consultation under the current 5‐Year Program.  As a result of this new

information, BOEMRE reinitiated ESA Section 7 consultation on the existing Gulf of Mexico lease

sale EIS with NMFS and the USFWS on 30 July 2010.  The NMFS responded with a letter to

BOEMRE on 24 September 2010, and the USFWS responded with a letter to BOEMRE on

27 September 2010.  However, NMFS and the USFWS have placed the consultation process on
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hold pending the results of the NRDA post‐Macondo spill data review, which has yet to be

released.  The existing consultation currently remains in effect (BOEMRE, 2011a).

BOEMRE (2011a,b) reexamined the impacts analyses presented in MMS (2007b, 2008) for the

five sea turtle species that inhabit the Gulf of Mexico based on additional information and in

consideration of the Macondo spill.  No new information was found that would alter the

potential impacts on sea turtles described in previous EISs.  In most foreseeable cases, exposure

to hydrocarbons persisting in the sea following the dispersal of an oil slick will result in sublethal

impacts (e.g., decreased health, reproductive fitness, and longevity; and increased vulnerability

to disease) to sea turtles.

Leatherbacks and loggerheads are the most likely species to be present near the lease area as

adults.  Green, hawksbill, and Kemp’s ridley turtles are typically inner shelf and nearshore

species, unlikely to occur near the lease area as adults.  Hatchlings or juveniles of any of the sea

turtle species may be present in deepwater areas, including the lease area, where they may be

associated with Sargassum and other flotsam.

Sea turtle nesting in the northern Gulf of Mexico can be summarized by species as follows:

 Loggerhead turtles – Loggerheads nest in significant numbers along the Florida Panhandle

and, to a lesser extent, from Texas through Alabama (MMS, 2007b).  The nearest significant

nesting area of loggerhead turtles is found in Louisiana, on beaches within the Breton NWR;

 Green and leatherback turtles – Green and leatherback turtles infrequently nest on Florida

Panhandle beaches (Florida Fish and Wildlife Conservation Commission, 2011);

 Kemp’s ridley turtles – The main Kemp’s ridley nesting site is Rancho Nuevo beach,

Tamaulipas, Mexico (NMFS et al., 2010).  Kemp’s ridley turtles typically do not nest

anywhere near the project area, although there have been occasional reports of Kemp’s

ridleys nesting in Alabama (Share the Beach, 2010); and

 Hawksbill turtles – Hawksbills typically do not nest anywhere near the project area.

IPFs potentially affecting sea turtles include drilling rig presence, noise, and lights; support

vessel and helicopter traffic; and two types of accidents ‐ a small fuel spill and a large oil spill

(WCD).  Effluent discharges are likely to have negligible impacts on sea turtles due to rapid

dispersion, the small area of ocean affected, and the intermittent nature of the discharges.  

Compliance with NTL 2012‐G01 will minimize the potential for marine debris‐related impacts on

sea turtles.

Impacts of Drilling Rig Presence, Noise, and Lights  

Offshore drilling activities produce a broad array of sounds at frequencies and intensities that

may be detected by sea turtles (Geraci and St. Aubin, 1987).  Potential impacts may include

behavioral disruption and temporary or permanent displacement from the area near the sound

source.  Certain sea turtles, especially loggerheads, may be attracted to offshore structures

(Lohoefener et al., 1990) and, thus, may be more susceptible to impacts from sounds produced

during routine operations.  Helicopters and service vessels may also affect sea turtles due to

machinery noise and/or visual disturbances.  The most likely impacts would be short‐term

behavioral changes such as diving and evasive swimming, disruption of activities, or departure

from the area.  Due to the limited scope and short duration of drilling activities, these

short‐term impacts are not expected to be biologically significant to sea turtle populations.

Artificial lighting can disrupt the nocturnal orientation of sea turtle hatchlings (Witherington,

1997; Tuxbury and Salmon, 2005).  However, hatchlings may rely less on light cues when they
Lloyd Ridge Block 621 October 2011

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are offshore than when they are emerging on the beach (Salmon and Wyneken, 1990).  The

NMFS (2007) concluded that the effects of lighting from offshore structures on sea turtles are

insignificant.

Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sea turtles, and there is also a risk of vessel

strikes.  Data show that vessel traffic is one cause of sea turtle mortality in the Gulf of Mexico

(Lutcavage et al., 1997).  While adult sea turtles are visible at the surface during the day and in

clear weather, they can be difficult to spot from a moving vessel when resting below the water

surface, during nighttime, or during periods of inclement weather.  To reduce the potential for

vessel strikes, BOEM/BSEE issued Joint NTL 2012‐G01, which recommends protected species

identification training and that vessel operators and crews maintain a vigilant watch for sea

turtles and slow down or stop their vessel to avoid striking protected species, and requires

operators to report sightings of any injured or dead protected species.  When sea turtles are

sighted, vessel operators and crews are required to attempt to maintain a distance of 45 m

(150 ft) or greater whenever possible.  Compliance with this NTL will minimize the likelihood of

vessel strikes as well as reduce the chance for disturbing sea turtles (NMFS, 2007).

Helicopter traffic also has the potential to disturb sea turtles.  However, while flying offshore,

helicopters maintain altitudes above 213 m (700 ft) during transit to and from the working area.  

This altitude will minimize the potential for disturbing sea turtles, and no significant impacts are

expected.

Impacts of a Small Fuel Spill

Potential spill impacts on sea turtles are discussed in recent EISs (MMS, 2007b, 2008) and the

NMFS Biological Opinion (NMFS, 2007).  For this EP, there are no unique site‐specific issues with

respect to spill impacts on these animals.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during fuel

transfer.  In the unlikely event of a spill, implementation of Anadarko’s OSRP is expected to

minimize potential impacts on sea turtles.  EP Section H provides detail on spill response

measures.  Given the open ocean location of the lease area, the duration of a small spill and

opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft.  However, due to the limited areal extent and short

duration of water quality impacts from a small fuel spill, no significant impacts would be

expected.

A small fuel spill in the lease area would be unlikely to affect sea turtle nesting beaches, as the

lease area is 143 miles (230 km) from the nearest shoreline (Louisiana).  As explained in
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Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up.

Impacts of a Large Oil Spill (WCD)

Impacts of oil spills on sea turtles can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants).  Direct physical and physiological effects can include skin irritation, inflammation,

or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of toxic fumes and

smoke (e.g., from in situ burning of oil); ingestion of oil (and dispersants) directly or via

contaminated food; and stress from the activities and noise of response vessels and aircraft.  

Complications of the above may lead to dysfunction of immune and reproductive systems,

physiological stress, declining physical condition, and death.  Behavioral responses can include

displacement of animals from prime habitat, disruption of social structure, changing food

availability and foraging distribution and/or patterns, changing reproductive

behavior/productivity, and changing movement patterns or migration.  In the unlikely event of a

spill, implementation of Anadarko’s OSRP is expected to minimize the potential for these types

of impacts on sea turtles.  EP Section H provides detail on spill response measures.

Studies of oil effects on loggerheads in a controlled setting (Lutcavage et al., 1995) suggest that

sea turtles show no avoidance behavior when they encounter an oil slick, and any sea turtle in

an affected area would be expected to be exposed.  Sea turtles’ diving behaviors also put them

at risk.  Sea turtles rapidly inhale a large volume of air before diving and continually resurface

over time, which may result in repeated exposure to volatile vapors and oiling (NMFS, 2007).

Spilled oil reaching sea turtle nesting beaches could have effects on nesting sea turtles and egg

development (NMFS, 2007).  An oiled beach could affect nest site selection or result in no

nesting at all (e.g., false crawls).  Upon hatching and successfully reaching the water, hatchlings

are subject to the same types of oil spill exposure hazards as adults.  Hatchlings that contact oil

residues while crossing a beach can exhibit a range of effects, from acute toxicity to impaired

movement and normal bodily functions (NMFS, 2007).

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb sea turtles and potentially result in vessel strikes, entanglement, or other injury or

stress.  Response vessels would operate in accordance with Joint NTL 2012‐G01 to reduce the

potential for striking or disturbing these animals, and therefore no significant impacts are

expected.

C.3.6 Piping Plover (Threatened)

The Piping Plover (Charadrius melodus) is a migratory shorebird that overwinters along the

southeastern U.S. and Gulf of Mexico coasts.  This threatened species is in decline as a result of

hunting, habitat loss and modification, predation, and disease (USFWS, 2003).  Critical

overwintering habitat has been designated, including beaches in Texas, Louisiana, Mississippi,

Alabama, and Florida (Figure 3).  Piping Plovers inhabit coastal sandy beaches and mudflats,

feeding by probing for invertebrates at or just below the surface.  They use beaches adjacent to

foraging areas for roosting and preening (USFWS, 2010a).  A species description is presented in a

recent lease sale EIS (MMS, 2007b).
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Environmental Impact Analysis for Initial Exploration Plan 

Figure 3. Location of selected environmental features in relation to the lease area.
Lloyd Ridge Block 621 October 2011

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A large oil spill (WCD) is the only IPF potentially affecting Piping Plovers.  There are no IPFs

associated with routine project activities that could affect these birds.  A small fuel spill in the

lease area would be unlikely to affect Piping Plovers because a small fuel spill would not be

expected to make landfall or reach coastal waters prior to breaking up (see explanation in

Section A.9.2).

Impacts of a Large Oil Spill (WCD)

The lease area is 144 miles (232 km) from the nearest shorelines inhabited by Piping Plovers

(Figure 3).  The revised OSRA results (BOEMRE, 2011a) summarized in Section A.9.3 (Table 3)

predict that during the spring there is a 4% probability that an oil spill from the lease area would

reach a shoreline designated as critical habitat for the Piping Plover within 10 days.  Plovers

could physically oil themselves while foraging on oiled shores or secondarily contaminate

themselves through ingestion of oiled intertidal sediments and prey (MMS, 2007b).  Plovers

congregate and feed along tidally exposed banks and shorelines, following the tide out and

foraging at the water’s edge.  It is possible that some deaths of Piping Plovers could occur,

especially if spills occur during winter months when plovers are most common along the coastal

Gulf or if spills contacted critical habitat.  Impacts could also occur from vehicular traffic on

beaches and other activities associated with spill cleanup.  Anadarko has extensive resources

available to protect and rehabilitate wildlife in the event of a spill reaching the shoreline, as

detailed in the OSRP.

C.3.7 Whooping Crane (Endangered)

The Whooping Crane (Grus americana) is an omnivorous wading bird and an endangered

species.  There are three wild populations in North America (Whooping Crane Eastern

Partnership, 2010).  One population winters along the Texas coast at Aransas NWR and

summers at Wood Buffalo National Park in Canada; this population represents the majority of

the world’s population of free‐ranging Whooping Cranes and reached a record population of

270 at Aransas NWR in December 2008 (Whooping Crane Eastern Partnership, 2010).  A

non‐migrating population has been reintroduced in central Florida, and another reintroduced

population summers in Wisconsin and migrates to the southeastern U.S. for the winter.  

Whooping Cranes breed, migrate, winter, and forage in a variety of habitats, including coastal

marshes and estuaries, inland marshes, lakes, ponds, wet meadows and rivers, and agricultural

fields (USFWS, 2007).  About 9,000 ha (22,240 ac) of salt flats on Aransas NWR and adjacent

islands comprise the principal wintering grounds of the Whooping Crane.  Aransas NWR is

designated as critical habitat for the species.  A species description is presented in a recent lease

sale EIS (MMS, 2007b).

A large oil spill (WCD) is the only IPF potentially affecting Whooping Cranes.  A small fuel spill in

the lease area would also be unlikely to affect Whooping Cranes, due to the distance from

Aransas NWR.  As explained in Section A.9.2, a small fuel spill would not be expected to make

landfall or reach coastal waters prior to breaking up.

Impacts of a Large Oil Spill (WCD)

A large oil spill is unlikely to affect Whooping Cranes as the lease area is approximately

540 miles (869 km) from its critical habitat designated in the Aransas NWR.  The revised

OSRA modeling (BOEMRE, 2011a) predicts that there is a 3% or less probability that an oil spill

originating in the lease area would reach the Aransas NWR within 30 days and a 17% probability

of oil reaching that area in 120 days.
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In the event of oil exposure, Whooping Cranes could physically oil themselves while foraging in

oiled areas or secondarily contaminate themselves through ingestion of contaminated shellfish,

frogs, and fishes.  It is possible that some Whooping Crane deaths could occur.  In the event of a

spill, Anadarko would work with the applicable State and Federal agencies to prevent impacts

from a spill.

C.3.8 Gulf Sturgeon (Threatened)

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is a threatened fish species that inhabits major

rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida

(Barkuloo, 1988; Wakeford, 2001).  An anadromous fish that migrates from the sea upstream

into coastal rivers to spawn in freshwater, it historically ranged from the Mississippi River to

Charlotte Harbor, Florida (Wakeford, 2001).  Today, this range has contracted to encompass

major rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida.  

Populations have been depleted or even extirpated throughout this range by fishing, shoreline

development, dam construction, water quality changes, and other factors (Barkuloo, 1988;

Wakeford, 2001).  These declines prompted the listing of the Gulf sturgeon as a threatened

species in 1991.  The best known populations occur in the Apalachicola and Suwannee Rivers in

Florida (Carr, 1996; Sulak and Clugston, 1998), the Choctawhatchee River in Alabama (Fox et al.,

2000), and the Pearl River in Mississippi/Louisiana (Morrow et al., 1998).  Critical habitat in the

Gulf extends from Lake Borgne, Louisiana (St. Bernard Parish) to Suwannee Sound, Florida

(Levy County) (NMFS, 2010b) (Figure 3).  A species description is presented in a recent lease sale

EIS (MMS, 2007b) and in the recovery plan for this species (USFWS and Gulf States Marine

Fisheries Commission, 1995).

A large oil spill (WCD) is the only IPF potentially affecting Gulf sturgeon.  There are no IPFs

associated with routine project activities that could affect these fish.  A small fuel spill in the

lease area would be unlikely to affect Gulf sturgeon because a small fuel spill would not be

expected to make landfall or reach coastal waters prior to breaking up (see explanation in

Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on Gulf sturgeon are discussed in recent lease sale EISs (MMS, 2007b,

2008) and by NMFS (2007).  For this EP, there are no unique site‐specific issues with respect to

this species.

The lease area is approximately 200 miles (323 km) from the nearest Gulf sturgeon critical

habitat.  The revised OSRA modeling (BOEMRE, 2011a) predicts that a spill in the lease area has

1% or less probability of contacting any coastal areas inhabited by Gulf sturgeon within

30 or 120 days.

In the event of oil reaching Gulf sturgeon habitat, the fish could be affected by direct ingestion,

ingestion of oiled prey, or the absorption of dissolved petroleum products through the gills.  

Based on the life history of this species, subadult and adult Gulf sturgeon would be most

vulnerable to an estuarine or marine oil spill, and would be vulnerable only from 1 September

through 30 April when this species is foraging in estuarine and shallow marine habitats

(NMFS, 2007).
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C.3.9 Smalltooth Sawfish (Endangered)

Smalltooth sawfish (Pristis pectinata) are found in the tropical and subtropical Atlantic Ocean.  

In the Western Atlantic they have historically ranged from New York to Brazil, including the Gulf

of Mexico and Caribbean Sea.  This sawfish primarily occurs in estuarine and coastal habitats

such as bays, lagoons, and rivers.  The smalltooth sawfish was listed as endangered on

1 April 2003, under the ESA.  Its critical habitat consists of two units: the Charlotte Harbor

Estuary Unit, which comprises approximately 89,621 ha (221,459 ac) of coastal habitat; and the

Ten Thousand Islands/Everglades Unit, which comprises approximately 250,506 ha (619,013 ac)

of coastal habitat.  The two units are located along the southwestern coast of Florida between

Charlotte Harbor and Florida Bay.

A large oil spill (WCD) is the only IPF potentially affecting smalltooth sawfish.  There are no IPFs

associated with routine project activities that could affect these fish.  A small fuel spill in the

lease area would be unlikely to affect smalltooth sawfish because a small fuel spill would not be

expected to make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on smalltooth sawfish are similar to those discussed for other coastal and

estuarine species in recent lease sale EISs (MMS, 2007b, 2008) and by the NMFS (2007) in its

Biological Opinion.  For this EP, there are no unique site‐specific issues with respect to

smalltooth sawfish.

In the event of oil reaching smalltooth sawfish habitat, the fish could be affected by direct

ingestion, ingestion of oiled prey, or the absorption of dissolved petroleum products through

the gills.

C.3.10 Beach Mice (Endangered)

Four subspecies of endangered beach mice (Peromyscus polionotus) occur on the barrier islands

of Alabama and the Florida Panhandle.  They are the Alabama, Choctawatchee, Perdido Key, and

St. Andrew beach mice.  Critical habitat has been designated for all four subspecies; Figure 3

shows the critical habitat combined for all four subspecies.  Species descriptions are provided in

a recent lease sale EIS (MMS, 2007b).

A large oil spill (WCD) is the only IPF potentially affecting beach mice.  There are no IPFs

associated with routine project activities that could affect these animals due to the distance

from shore and the lack of any onshore support activities near their habitat.  A small fuel spill in

the lease area would not affect beach mice because a small fuel spill would not be expected to

make landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on beach mice are discussed in recent lease sale EISs (MMS, 2007b,

2008).  For this EP, there are no unique site‐specific issues with respect to these species that

were not analyzed in these documents.

The lease area is about 199 miles (320 km) southwest from the nearest beach mouse critical

habitat.  The revised OSRA modeling summarized in Section A.9.3 predicts that a spill in the
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Environmental Impact Analysis for Initial Exploration Plan Page 46

lease area has a 1% or less probability of reaching either the Alabama or Florida shorelines

inhabited by beach mice within 120 days.

In the event of oil contacting these beaches, beach mice could experience several types of direct

and indirect impacts.  Contact with spilled oil could cause skin and eye irritation and subsequent

infection; matting of fur; irritation of sweat glands, ear tissues, and throat tissues; disruption of

sight and hearing; asphyxiation from inhalation of fumes; and toxicity from ingestion of oil and

contaminated food.  Indirect impacts could include reduction of food supply, destruction of

habitat, and fouling of nests.  Impacts could also occur from vehicular traffic and other activities

associated with spill cleanup.  However, any such impacts are unlikely due to the distance from

shore and response actions that would occur in the event of a spill.

C.3.11 Elkhorn Coral (Endangered)  

Elkhorn coral (Acropora palmata) is found primarily in shallow waters with temperatures ranging

between 26°C and 30°C (79°F and 86°F) and significant water movement.  Elkhorn coral was

once one of the most abundant species in waters ranging from 1 to 5 m (3.3 to 16 ft) deep in

tropical and subtropical waters.  In the northern Gulf, elkhorn coral has been found within the

coral cap region of the Flower Garden Banks National Marine Sanctuary (Flower Garden Banks

National Marine Sanctuary, 2011).

There are no IPFs associated with routine project activities that could affect this species in the

northern Gulf.  A small fuel spill would not affect elkhorn coral colonies because the oil would

float and dissipate on the sea surface.  A WCD would be unlikely to affect the coral cap region of

the Flower Gardens Bank because of the water depth of the area.  Although subsurface plumes

were reported following the Macondo spill, these plumes resulted from the use of subsea

dispersants at the seafloor.   

C.4 Coastal and Marine Birds

C.4.1 Marine Birds

Marine birds include seabirds and other species that may occur in the pelagic environment of

the project area (Clapp et al., 1982a,b, 1983; Peake, 1996; Hess and Ribic, 2000).  Seabirds spend

much of their lives offshore over the open ocean, except during breeding season when they nest

along the coast.  In addition, other birds such as waterfowl, marsh birds, and shorebirds may

occasionally be present over open ocean areas.  No endangered or threatened bird species are

likely to occur at the project area due to the distance from shore.  For a discussion of shorebirds

and coastal nesting birds, see Section C.4.2.

Seabirds of the northern Gulf of Mexico were surveyed from ships during the GulfCet II program.  

Hess and Ribic (2000) reported that terns, storm‐petrels, shearwaters, and jaegers were the

most frequently sighted seabirds in the deepwater area.  From these surveys, four ecological

categories of seabirds were documented in the deepwater areas of the Gulf: summer migrants

(shearwaters, storm petrels, boobies); summer residents that breed in the Gulf (Sooty Tern,

Least Tern, Sandwich Tern, Magnificent Frigatebird); winter residents (gannets, gulls, jaegers);

and permanent resident species (Laughing Gulls, Royal Terns, Bridled Terns) (Hess and Ribic,

2000).
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Common seabird species include Wilson’s Storm‐Petrel (Oceanites oceanicus), Magnificent

Frigatebird (Fregata magnificens), Northern Gannet (Morus bassanus), Masked Booby

(Sula dactylatra), Brown Booby (Sula leucogaster), Cory’s Shearwater (Calonectris diomedea),

Greater Shearwater (Puffinus gravis), and Audubon’s Shearwater (Puffinus lherminieri).  Seabirds

are distributed Gulf‐wide and are not specifically associated with the lease area.

Relationships with hydrographic features were found for several seabird species, possibly due to

effects of hydrography on nutrient levels and productivity of surface waters where birds forage.  

The GulfCet II study did not estimate bird densities; however, Powers (1987) indicates that

seabird densities over the open ocean typically are <10 birds/km2.  

Trans‐Gulf migrant birds including shorebirds, wading birds, and terrestrial birds may also be

present in the lease area.  Migrant birds may use offshore structures and rigs for resting,

feeding, or as temporary shelter from inclement weather (Russell, 2005).  Some birds may be

attracted to offshore structures because of the lights and the fish populations that aggregate

around these structures.

IPFs potentially affecting marine and pelagic birds include drilling rig presence, noise, and lights;

support vessel and helicopter traffic; and two types of accidents ‐ a small fuel spill and a large oil

spill (WCD).  Effluent discharges are likely to have negligible impacts on the birds due to rapid

dispersion, the small area of ocean affected, the intermittent nature of the discharges, and the

mobility of these animals.  Compliance with BSEE NTL 2012‐G01 will minimize the potential for

marine debris‐related impacts on birds.

Impacts of Drilling Rig Presence, Noise, and Lights

Birds that frequent rigs may be exposed to contaminants including air pollutants and routine

discharges, but significant impacts are unlikely due to rapid dispersion.  Birds migrating over

water have been known to strike offshore structures, resulting in death or injury (Wiese et al.,

2001; Russell, 2005).  Mortality of migrant birds at tall towers and other land‐based structures

has been reviewed extensively, and the mechanisms involved in rig collisions appear to be

similar.  In some cases, migrants simply do not see a part of the rig until it is too late.  In other

cases, navigation may be disrupted by noise (Russell, 2005).  On the other hand, offshore

structures are suitable stopover habitats for most trans‐Gulf migrant species, and most of the

migrants that stop over on rigs probably benefit from their stay, particularly in spring

(Russell, 2005).  Due to the limited scope and short duration of drilling activities described in this

EP, any impacts on populations of either seabirds or trans‐Gulf migrant birds are not expected

to be significant.

A recent study in the North Sea indicated that rig lighting causes circling behavior in various

birds, especially on cloudy nights; apparently the birds’ geomagnetic compass is upset by the

red part of the spectrum from the lights currently in use (Nederlandse Aardolie Maatschappij,

2007).  The numbers varied greatly, from none at all to some tens of thousands of birds per

night per rig, with an apparent effect radius of up to 3 miles (5 km).  A study in the Gulf of

Mexico also noted the phenomenon but did not recommend mitigation (Russell, 2005).  Factors

to consider in evaluating this impact in the Gulf of Mexico would include the lower incidence of

cloudy and foggy days in the Gulf of Mexico versus the North Sea.  Due to the limited scope and

short duration of drilling activities proposed in this EP, lighting impacts, collisions, or other

adverse effects are unlikely, and no significant impacts are expected.
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Impacts of Support Vessel and Helicopter Traffic

Support vessels and helicopters are unlikely to significantly disturb pelagic birds in open,

offshore waters.  It is likely that individual birds would experience, at most, only short‐term

behavioral disruption, and the impact would not be significant.

Impacts of a Small Fuel Spill

Potential spill impacts on marine birds are discussed in recent EISs (MMS, 2007b, 2008).  For this

EP, there are no unique site‐specific issues with respect to spill impacts on these animals.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will reduce the potential for impacts on marine and pelagic birds.  

EP Section H provides detail on spill response measures.  Given the open ocean location of the

lease area, the duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Birds exposed to oil on the sea surface could experience direct physical and physiological effects

including skin irritation; chemical burns of skin, eyes, and mucous membranes; and inhalation of

toxic fumes.  Due to the limited areal extent and short duration of water quality impacts from a

small fuel spill, secondary impacts due to ingestion of oil via contaminated prey or reductions in

prey abundance are unlikely.  Due to the low densities of birds in open ocean areas, the small

area affected, and the brief duration of the surface slick, no significant impacts on pelagic birds

would be expected.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine and pelagic birds are discussed in recent EISs (MMS, 2007b,

2008).  For this EP, there are no unique site‐specific issues with respect to spill impacts on these

animals.

BOEMRE has reexamined the analyses for coastal and marine birds presented in MMS (2007b,

2008) and determined that no new information was found that would alter the potential

impacts on marine and pelagic birds (BOEMRE, 2011a,b).

Pelagic seabirds could be exposed to oil from a spill at the project area.  Hess and Ribic (2000)

reported that terns, storm‐petrels, shearwaters, and jaegers were the most frequently sighted

seabirds in the deepwater Gulf of Mexico (>200 m).  Powers (1987) indicates that seabird

densities over the open ocean typically are <10 birds/km2

.  The number of pelagic birds that

could be affected in open, offshore waters would depend on the extent and persistence of the

oil slick.
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The recent Macondo spill provides relevant information about the species of pelagic birds that

may be affected in the event of a large oil spill.  Birds that have been treated for oiling include

several pelagic species such as the Northern Gannet, Magnificent Frigatebird, and Masked

Booby (International Bird Rescue Research Center, 2010).  The Northern Gannet is among the

species with the largest numbers of birds affected by the spill.

C.4.2 Shorebirds and Coastal Nesting Birds

Threatened and endangered bird species (Piping Plover and Whooping Crane) have been

discussed previously in Section C.3.  Various species of non‐endangered birds are also found

along the northern Gulf Coast, including diving birds, shorebirds, marsh birds, wading birds, and

waterfowl.  Gulf Coast marshes and beaches also provide important feeding grounds and

nesting habitats.  Species that breed on beaches, flats, dunes, bars, barrier islands, and similar

habitats include the Sandwich Tern, Wilson’s Plover, Black Skimmer, Forster’s Tern, Gull‐billed

Tern, Laughing Gull, Least Tern, and Royal Tern (USFWS, 2010b).  Additional information is

presented in recent lease sale EISs (MMS, 2007b, 2008).

The Brown Pelican (Pelecanus occidentalis) was delisted from Federal endangered status in 2009

(USFWS, 2010c).  However, this species is listed as a species of greatest conservation need by

the State of Mississippi (Mississippi Department of Wildlife, Fisheries and Parks, 2011) and as a

species of special concern by the State of Florida (Florida Fish and Wildlife Conservation

Commission, 2011).  Brown Pelicans inhabit coastal habitats and forage within both coastal

waters and waters of the inner continental shelf.  Aerial and shipboard surveys, including

GulfCet and GulfCet II, indicate that Brown Pelicans do not occur in deep offshore waters

(Fritts and Reynolds, 1981; Peake, 1996; Hess and Ribic, 2000).  Nearly half the southeastern

population of Brown Pelicans lives in the northern Gulf Coast, generally nesting on protected

islands (USFWS, 2010b).

The Southern Bald Eagle (Haliaeetus leucocephalus) was delisted from its threatened status in

the lower 48 states on 28 June 2007.  The Bald Eagle is a terrestrial raptor widely distributed

across the southern U.S., including coastal habitats along the Gulf of Mexico.  The Gulf Coast is

inhabited by both wintering migrant and resident Bald Eagles (Johnsgard, 1990; Ehrlich et al.,

1992).

IPFs potentially affecting shorebirds and coastal nesting birds include support vessel and

helicopter traffic and a large oil spill (WCD).  A small fuel spill in the lease area would be unlikely

to affect shorebirds or coastal nesting birds, as the lease area is 143 miles (230 km) from the

nearest shoreline (Louisiana).  As explained in Section A.9.2, a small fuel spill would not be

expected to make landfall or reach coastal waters prior to breaking up.  Compliance with BSEE

NTL 2012‐G01 will minimize the potential for marine debris‐related impacts on shorebirds.

Impacts of Support Vessel and Helicopter Traffic

Support vessels and helicopters will transit coastal areas near Port Fourchon and Houma,

Louisiana, where shorebirds and coastal nesting birds may be found.  These activities could

periodically disturb individuals or groups of birds within sensitive coastal habitats (e.g., wetlands

that may support feeding, resting, or breeding birds).

Vessel traffic may disturb some foraging and resting birds.  Flushing distances vary between

species and between individuals (Rodgers and Schwikert, 2002).  The disturbances will be
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limited to flushing birds away from vessel pathways; known distances are from 20 to 49 m

(65 to 160 ft) for personal watercraft and 23 to 58 m (75 to 190 ft) for an outboard‐powered

boat (Rodgers and Schwikert, 2002).  Flushing distances may be similar or less for the support

vessels to be used for Anadarko’s project, and some species such as gulls are attracted to boats.  

Support vessels will not approach nesting or breeding areas on the shoreline, so disturbances to

nesting birds, eggs, and chicks is not expected.  Vessel operators will use designated navigation

channels and comply with posted speed and wake restrictions while transiting sensitive inland

waterways.  Due to the limited scope and short duration of drilling activities, any short‐term

impacts are not expected to be biologically significant to coastal bird populations.

Aircraft traffic can cause some disturbance to birds onshore and offshore.  Responses are highly

dependent on the type of aircraft, the bird species, the activities that animals were previously

engaged in, and previous exposures to overflights (Efroymson et al., 2000).  Helicopters seem to

cause the most intense responses over other human disturbances for some species (Bélanger

and Bédard, 1989).  However, Federal Aviation Administration Advisory Circular No. 91‐36D

recommends that pilots maintain a minimum altitude of 610 m (2,000 ft) when flying over

noise‐sensitive areas such as wildlife refuges, parks, and areas with wilderness characteristics.  

This is greater than the distance (slant range) at which aircraft overflights have been reported to

cause behavioral effects on most species of birds studied (Efroymson et al., 2000).  With these

guidelines in effect, it is likely that individual birds would experience, at most, only short‐term

behavioral disruption.

Impacts of Large Oil Spill (WCD)

Data from the Macondo spill provide additional information about the species of coastal birds

that may be affected in the event of a catastrophic spill of a similar nature and duration.  This

information supplements the analysis presented in the lease sale EIS (MMS, 2007b).  According

to USFWS (2010d) and based on the latest reports, about 5,000 dead birds have been collected

since the spill began, and about 1,900 of the dead animals were visibly oiled.  In addition, over

2,000 oiled birds have been collected alive and about 1,200 released (NMFS, 2010c).  According

to the International Bird Rescue Research Center (2010), bird species that have been treated for

oiling include the following:

 Brown Pelican

 White Pelican

 Masked Booby

 Magnificent Frigatebird

 Laughing Gull

 Herring Gull

 Northern Gannet

 Black Crowned Night Heron

 Tri‐colored Heron

 Green Heron

 Cattle Egret

 Snowy Egret

 Reddish Egret

 Least Bittern

 Common Tern

 Royal Tern

 Caspian Tern

 Sandwich Tern

 Forster’s Tern

 Black Tern

 Gull‐billed Tern

 Least Tern

 Black Skimmer

 Black Oystercatcher

 White Ibis

 Roseate Spoonbill

 Willet

 Sanderling

 Dunlin

 Semipalmated Sandpiper

 Killdeer

 King Rail

 Clapper Rail

 Virginia Rail
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According to the USFWS (2010d), species with the largest numbers of dead oiled birds were

Laughing Gull, Northern Gannet, Brown Pelican, Royal Tern, Black Skimmer, Least Tern,

unidentified Gull, and unidentified Tern.  There are no reports of Bald Eagle oiling.

Coastal birds can be exposed to oil as they float on the water surface, dive during foraging, or

wade in oiled coastal waters.  Oiled birds can lose the ability to fly, dive for food, or float on the

water, which could lead to drowning (USFWS, 2010e).  Oil interferes with the water repellency

of feathers and can cause hypothermia in the right conditions.  As birds groom themselves, they

can ingest and inhale the oil on their bodies.  Scavengers such as Bald Eagles and gulls can be

exposed to oil by feeding on carcasses of contaminated fish and wildlife.  While ingestion can kill

animals immediately, more often it results in lung, liver, and kidney damage, which can lead to

death.  Bird eggs may be damaged if an oiled adult sits on the nest.

As noted above, the Brown Pelican was recently removed from the Federal endangered species

list.  Over 300 dead Brown Pelicans were collected in the Gulf following the Macondo spill,

(USFWS, 2010d).  These data indicate that Brown Pelicans may be particularly at risk of oiling in

the event of a catastrophic spill reaching coastal waters.  Issues for Brown Pelicans include direct

contact with oil, disturbance by cleanup activities, and long‐term habitat contamination.

C.5 Fisheries Resources

C.5.1 Pelagic Communities and Ichthyoplankton

Biggs and Ressler (2000) reviewed the biology of pelagic communities in the deepwater

environment of the northern Gulf of Mexico.  The biological oceanography of the region is

dominated by the influence of the Loop Current, whose surface waters are among the most

oligotrophic in the world’s oceans.  Superimposed on this low‐productivity condition are

productive “hot spots” associated with entrainment of nutrient‐rich Mississippi River water and

mesoscale oceanographic features.  Anticyclonic and cyclonic hydrographic features play an

important role in determining biogeographic patterns and controlling primary productivity in the

northern Gulf of Mexico (Biggs and Ressler, 2000).

Most fishes inhabiting shelf or oceanic waters of the Gulf of Mexico have planktonic eggs and

larvae (Ditty, 1986; Ditty et al., 1988; Richards et al., 1989, 1993).  Pelagic eggs and larvae

become part of the planktonic community for various lengths of time (10 to 100 days,

depending on the species) (MMS, 2007b).

IPFs potentially affecting pelagic communities and ichthyoplankton include drilling rig presence,

noise, and lights; effluent discharges; water intakes; and two types of accidents ‐ a small fuel

spill and a large oil spill (WCD).

Impacts of Drilling Rig Presence, Noise, and Lights

The drilling rig, as a floating structure in the deepwater environment, will act as a fish‐attracting

device (FAD).  In oceanic waters, the FAD effect would be most pronounced for epipelagic fishes

such as tunas, dolphin, billfishes, and jacks, which are commonly attracted to fixed and drifting

surface structures (Holland et al., 1990; Higashi, 1994; Relini et al., 1994; MMS, 2000, 2007b,

2008).  This FAD effect could possibly enhance the feeding of epipelagic predators by attracting
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and concentrating smaller fish species.  Because the drilling rig is a single, temporary structure,

impacts on fish populations, whether beneficial or adverse, are considered minor.

Impacts of Effluent Discharges

Treated sanitary and domestic wastes may have a slight effect on the pelagic environment in the

immediate vicinity of these discharges.  These wastes may have elevated levels of nutrients,

organic matter, and chlorine, but should be diluted rapidly to undetectable levels within tens to

hundreds of meters from the source.  Minimal impacts on water quality, plankton, and nekton

are anticipated.

Deck drainage may have a slight effect on the pelagic environment in the immediate vicinity of

these discharges.  Deck drainage from contaminated areas will be passed through an

oil‐and‐water separator prior to release, and discharges will be monitored for visible sheen.  The

discharges may have slightly elevated levels of hydrocarbons but should be diluted rapidly to

undetectable levels within tens to hundreds of meters from the source.  Minimal impacts on

water quality, plankton, and nekton are anticipated.

Other discharges in accordance with the NPDES permit, such as desalination unit brine and

uncontaminated cooling water, fire water, and ballast water, are expected to be diluted rapidly

and have little or no impact on water column biota.

Impacts of Water Intakes

Seawater will be drawn from the ocean for once‐through, non‐contact cooling of machinery

on the drilling rig.  Rigs considered for use for activities described in this EP are not “new”

facilities as defined by the NPDES permit and therefore are not subject to the cooling water

intake regulations for Phase III facilities under Section 316(b) of the Clean Water Act.

The intake of seawater for cooling water will entrain plankton.  The low intake velocity should

allow most strong‐swimming juvenile fishes and smaller adults to escape entrainment or

impingement.  However, drifting plankton would not be able to escape entrainment with the

exception of a few fast‐swimming larvae of certain taxonomic groups.  Those organisms

entrained may be stressed or killed, primarily through changes in water temperature during the

route from cooling intake structure to discharge structure and mechanical damage (turbulence

in pumps and condensers).  Due to the limited scope and short duration of drilling activities, any

short‐term impacts of entrainment are not expected to be biologically significant to plankton or

ichthyoplankton populations.

Impacts of a Small Fuel Spill

Potential spill impacts on fisheries resources are discussed in recent EISs (MMS, 2007b, 2008).  

For this EP, there are no unique site‐specific issues with respect to spill impacts.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will mitigate the potential for impacts on pelagic communities, including

ichthyoplankton.  EP Section H provides detail on spill response measures.  Given the open

ocean location of the lease area, the duration of a small spill and opportunity for impacts to

occur would be very brief.
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A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

A small fuel spill could have localized impacts on phytoplankton, zooplankton, and nekton.  Due

to the limited areal extent and short duration of water quality impacts, a small fuel spill would

be unlikely to produce detectable impacts on pelagic communities.

Impacts of a Large Oil Spill (WCD)

A large oil spill could affect water column biota including phytoplankton, zooplankton,

ichthyoplankton, and nekton.  A large spill that persisted for weeks or months would be more

likely to affect these communities.  While adult and juvenile fishes may actively avoid a large

spill, planktonic eggs and larvae would be unable to avoid contact.  Eggs and larvae of fishes are

especially vulnerable to oiling because they inhabit the upper layers of the water column, and

they will die if exposed to certain toxic fractions of spilled oil.  Impacts potentially would be

greater if local‐scale currents retained planktonic larval assemblages (and the floating oil slick)

within the same water mass.

C.5.2 Essential Fish Habitat

Essential Fish Habitat (EFH) is defined as those waters and substrate necessary to fish for

spawning, breeding, feeding, and growth to maturity.  Under the Magnuson‐Stevens Fishery

Conservation and Management Act, as amended, Federal agencies are required to consult on

activities that may adversely affect EFH designated in Fishery Management Plans developed by

the regional Fishery Management Councils.

The BOEMRE (2011a,b) has reexamined the analysis for fish resources and EFH presented in

recent lease EISs (MMS, 2007a,b), in consideration of the Macondo event.  No substantial new

information was found that would alter the impact conclusions for fish resources and EFH

presented in MMS (2007a,b).

The Gulf of Mexico Fishery Management Council (GMFMC) has prepared Fishery Management

Plans for corals and coral reefs, shrimps, stone crab, spiny lobster, reef fishes, coastal migratory

pelagic fishes, and red drum.  In 2005, the EFH for these managed species was redefined in

Generic Amendment No. 3 to the various Fishery Management Plans (GMFMC, 2005).  The EFH

for most of these GMFMC‐managed species is on the continental shelf in waters shallower than

183 m (600 ft).  The shelf edge is the outer boundary for coastal migratory pelagic fishes, reef

fishes, and shrimps.  EFH for corals and coral reefs includes some shelf‐edge topographic

features on the Texas‐Louisiana OCS, the nearest of which is in the West Delta Area, South

Addition Block 147, located 141 miles (226 km) west of the lease area along the shelf edge south

of Louisiana.

Highly migratory pelagic fishes, which occur as transients in the lease area, are the only

remaining group for which EFH has been identified in the deepwater Gulf of Mexico.  Species in

this group, including tunas, swordfishes, billfishes, and sharks, are managed by NMFS.  Highly
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Environmental Impact Analysis for Initial Exploration Plan Page 54

migratory species with EFH at or near the lease area include the following species and life stages

(NMFS, 2009):

 Atlantic bluefin tuna (spawn, eggs,

larvae)

 Bigeye thresher shark (all)

 Blue marlin (juveniles, adults)

 Longfin mako shark (all)

 Longbill spearfish (juveniles, adults)

 Oceanic whitetip shark (all)

 Silky shark (all)

 Skipjack tuna (spawn, juveniles,

adults)

 Swordfish (larvae, juveniles)

 Tiger shark (adults)

 White marlin (juveniles, adults)

 Yellowfin tuna (spawn, juveniles,

adults)

Recent research indicates the central and western Gulf of Mexico may be important spawning

habitat for Atlantic bluefin tuna, and NMFS (2009) has designated a Habitat Area of Particular

Concern (HAPC) for this species.  The HAPC covers much of the deepwater Gulf of Mexico,

including the lease area (Figure 3).  The areal extent of the HAPC is approximately 300,000 km2

(15,000 mi2).  The prevailing assumption is that Atlantic bluefin tuna follow an annual cycle of

foraging in June through March off the eastern U.S. and Canadian coasts, followed by migration

to the Gulf of Mexico to spawn in April, May, and June (NMFS, 2009).

On 27 May 2011, after an extensive scientific review, NOAA announced that Atlantic bluefin

tuna currently do not warrant species protection under the ESA.  NOAA said the species would

be classified as a species of concern, however, effectively placing bluefin tuna on a watch list as

the agency awaits new data on the impact of a stricter international management regimen.

A new amendment to the original EFH Generic Amendment was finalized in 2005

(GMFMC, 2005).  One of the most significant proposed changes in this amendment reduced the

extent of EFH relative to the 1998 Generic Amendment by removing the EFH description and

identification from waters between 100 fathoms and the seaward limit of the Exclusive

Economic Zone (EEZ).  The Highly Migratory Species Fisheries Management Plan was amended

in 2009 to update EFH and HAPC to include the bluefin tuna spawning area (NMFS, 2009).

There are current NTLs (2009‐G39 and 2009‐G40) that provide guidance and clarification of the

regulations with respect to biologically sensitive underwater features and areas and benthic

communities that are considered EFH (MMS, 2009a,b).  A new EFH consultation has been

initiated between BOEMRE’s Gulf of Mexico Region and NOAA’s Southeastern Region.  Some

EFH requirements may change with the new agreement.  Until the new agreement is in place,

the 1999 Programmatic Consultation with the elements described above will be followed

(BOEMRE, 2011a,b).

Other HAPCs have been identified by the GMFMC (2005).  These include the Florida Middle

Grounds, Madison‐Swanson Marine Reserve, Tortugas North and South Ecological Reserves,

Pulley Ridge, and several individual reefs and banks of the northwestern Gulf of Mexico

(Figure 3).  The nearest of these is Jakkula Bank, located approximately 241 miles (387 km)

west‐northwest of the lease area.
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Routine IPFs potentially affecting EFH include drilling rig presence, noise, and lights; effluent

discharges; water intakes; and two types of accidents – a small fuel spill and a large oil spill

(WCD).

Impacts of Drilling Rig Presence, Noise, and Lights

The drilling rig, as a floating structure in the deepwater environment, will act as an FAD.  In

oceanic waters, the FAD effect would be most pronounced for epipelagic fishes such as tunas,

dolphin, billfishes, and jacks, which are commonly attracted to fixed and drifting surface

structures (Holland et al., 1990; Higashi, 1994; Relini et al., 1994; MMS, 2000, 2007b, 2008).  

This FAD effect would possibly enhance feeding of epipelagic predators by attracting and

concentrating smaller fish species.  Because the drilling rig is a single, temporary structure, any

impacts on EFH for highly migratory pelagic fishes are considered minor.

Impacts of Effluent Discharges

Other effluent discharges affecting EFH by diminishing ambient water quality include drilling

muds and cuttings, treated sanitary and domestic wastes, deck drainage, and miscellaneous

discharges such as desalination unit brine and uncontaminated cooling water, fire water, and

ballast water.  Impacts on water quality have been discussed previously.  No significant impacts

on EFH for highly migratory pelagic fishes are expected from these discharges.

Impacts of Water Intakes

As noted previously, cooling water intake will cause entrainment and impingement of plankton,

including fish eggs and larvae (ichthyoplankton).  Due to the limited scope and short duration of

drilling activities, any short‐term impacts on EFH for highly migratory pelagic fishes are not

expected to be biologically significant.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will help diminish the potential for impacts on EFH.  EP Section H provides

detail on spill response measures.  Given the open ocean location of the lease area, the duration

of a small spill and opportunity for impacts to occur would be very brief.

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008).  For this EP,

there are no unique site‐specific issues with respect to spill impacts.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products.  The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures.  Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

A small fuel spill could have localized impacts on EFH for highly migratory pelagic fishes,

including tunas, swordfishes, billfishes, and sharks.  These species occur as transients in the

lease area.  A spill would also produce short‐term impact on water quality in the HAPC for
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Environmental Impact Analysis for Initial Exploration Plan Page 56

spawning bluefin tuna, which covers much of the deepwater Gulf of Mexico.  The areal extent of

the affected area would represent a negligible portion of the HAPC.

A small fuel spill would not affect EFH for corals and coral reefs, the nearest EFH being the

topographic feature in the West Delta Area, South Addition, Block 147, located 141 miles

(226 km) west of the lease area.  A small fuel spill would float and dissipate on the sea surface

and would not contact these features.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008).  For this EP,

there are no unique site‐specific issues with respect to EFH.

An oil spill in offshore waters would temporarily increase hydrocarbon concentrations on the

water surface and potentially the subsurface as well.  Given the extent of EFH designations in

the Gulf of Mexico (GMFMC, 2005; NMFS, 2009), some impact on EFH would be unavoidable.

A large spill could affect the EFH for many managed species including shrimps, stone crab, spiny

lobster, reef fishes, coastal migratory pelagic fishes, and red drum.  It would result in adverse

impacts on water quality and water column biota including phytoplankton, zooplankton, and

nekton.  In coastal waters, sediments could be contaminated and result in persistent

degradation of the seafloor habitat for managed demersal fish and shellfish species.

The lease area is within the HAPC for spawning Atlantic bluefin tuna (NMFS, 2009).  A large spill

could temporarily degrade the HAPC due to increased hydrocarbon concentrations in the water

column, with the potential for lethal or sublethal impacts on spawning tuna.  Potential impacts

would depend in part on the timing of a spill, as this species migrates to the Gulf of Mexico to

spawn in April, May, and June (NMFS, 2009).

The topographic feature in the West Delta Area, South Addition, Block 147, located 141 miles

(226 km) west of the lease area, is designated as EFH under the corals and coral reefs

management plan.  An accidental spill would be unlikely to affect this area, since a surface slick

would not reach these features due to their depth.

C.6 Archaeological Resources

C.6.1 Shipwreck Sites

The BOEMRE (2011a,b) reexamined the analyses for archaeological resources presented in

MMS (2007b, 2008), based on additional information available since the publication of these

two documents and in consideration of the Macondo oil spill.  Substantial new information that

alters the impact conclusion for archaeological resources presented in MMS (2007b, 2008) has

come to light as a result of BOEMRE‐sponsored studies and industry surveys.  Specifically,

evidence of damage to significant cultural resources (i.e., historic shipwrecks) has been shown

to have occurred because of an incomplete knowledge of seafloor conditions in lease areas

>200 m (656 ft) deep that have been exempted from high‐resolution surveys.  Since significant

historic shipwrecks have recently been discovered outside the previously designated

high‐probability areas (some of which show evidence of impacts from permitted activities prior

to their discovery), beginning in 2011 a survey will be required for exploration and development

projects.  The LL 621 area is not on the list of leases with a high potential for historic shipwrecks.  

There were no indications of wrecks or other archaeological resources detected during the site
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clearance survey (GEMS, 2009).  Anadarko will abide by the applicable requirements of

NTL 2005‐G07, which stipulate that work be stopped at the project site should any previously

undetected archaeological resource be discovered after work has begun until appropriate

surveys and evaluations have been completed.

Because there are no shipwreck sites in the lease area, there are no routine IPFs that are likely

to affect shipwrecks.  The impacts of a large oil spill (WCD) is the only accident IPF considered.  

A small fuel spill would not affect shipwrecks because the oil would float and dissipate on the

sea surface.

Impacts of a Large Oil Spill (WCD)

MMS (2007b) estimated that a severe subsurface blowout could resuspend and disperse

sediments within a 300‐m (984‐ft) radius.  Because there are no historic shipwrecks in the lease

area, this impact would not be relevant.

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

archaeological sites beyond the immediate vicinity of the wellhead (i.e., due to physical impacts

of a blowout) because the oil would rise quickly to the sea surface directly over the spill location.  

However, during the Macondo spill, subsurface plumes were reported at a water depth of about

1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsite and persisting for more

than a month (Camilli et al., 2010).  The subsurface plumes apparently resulted from the use of

dispersants at the wellhead (Joint Analysis Group, 2010c).  While the behavior and impacts of

subsurface plumes are not well known, a subsurface plume could have the potential to contact

shipwreck sites beyond the 300‐m (984‐ft) radius estimated by MMS (2007a, 2008), depending

on its extent, trajectory, and persistence.  If oil from a subsea spill should come into contact with

wooden shipwrecks on the seafloor, it could adversely affect their condition or preservation.  

Should there be any indication that potential shipwreck sites could be affected, in accordance

with NTL 2005‐G07 Anadarko will immediately halt operations, take steps to ensure that the site

is not disturbed in any way, and contact the BOEM Regional Supervisor, Leasing and

Environment, within 48 hours of its discovery.  Anadarko would cease all operations within

305 m (1,000 ft) of the site until the Regional Supervisor provides instructions on steps to take

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

A spill entering shallow coastal waters could conceivably contaminate an undiscovered

shipwreck site.  As noted by MMS (2007b), should an oil spill contact a coastal historic site, such

as a fort or a lighthouse, the major impact would be a temporary, reversible visual impact from

oil contact and contamination of the site and its environment.

C.6.2 Prehistoric Archaeological Sites

Available evidence suggests that sea level in the northern Gulf of Mexico was at least 90 m

(295 ft), and possibly as much as 130 m (427 ft), lower than present sea level during the period

20,000 to 17,000 years Before Present (B.P.) (Nelson and Bray, 1970).  Sea level in the northern

Gulf reached its present stand around 3,500 years B.P. (Pearson et al., 1986).

During periods that the continental shelf was exposed above sea level, the area was open to

habitation by prehistoric peoples.  The advent of early man into the Gulf of Mexico region is

currently accepted to be around 12,000 years B.P. (Aten, 1983).  The sea‐level curve for the

northern Gulf of Mexico proposed by Coastal Environments, Inc. (CEI) suggests that sea level at
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12,000 years B.P. would have been approximately 45 to 60 m (148 to 197 ft) below the

present‐day sea level (CEI, 1977, 1982).  On this basis, the continental shelf shoreward of the

45‐ to 60‐m (148‐ to 197‐ft) bathymetric contours has potential for prehistoric sites dating after

12,000 years B.P.  Because of inherent uncertainties in both the depth of sea level and the entry

date of prehistoric man into North America, the MMS adopted the 60‐m (197‐ft) water depth as

the seaward extent for archaeological site potential in Gulf of Mexico region.

With water depths of 2,769.71 to 2,770.32 m (9,087 to 9,089 ft), the wellsites are well beyond

the 60‐m (197‐ft) depth contour used by the BOEM as the seaward extent for prehistoric

archaeological site potential in the Gulf of Mexico.  Because prehistoric archaeological sites are

not found in the lease area, the only relevant accident IPF is a large oil spill (WCD).  A small fuel

spill would not affect prehistoric archaeological resources because the oil would float and

dissipate on the sea surface.

Impacts of a Large Oil Spill (WCD)

Because prehistoric archaeological sites are not found in the lease area, they would not be

affected by the physical effects of a subsea blowout.  The MMS (2007b) estimates that a severe

subsurface blowout could resuspend and disperse sediments within a 300‐m (984‐ft) radius.

Along the northern Gulf Coast, prehistoric sites occur frequently along the barrier islands and

mainland coast and along the margins of bays and bayous (MMS, 2007b).  If a spill did reach a

prehistoric site along these shorelines it could coat fragile artifacts or site features and

compromise the potential for radiocarbon dating organic materials in a site (although other

dating methods are available and it is possible to decontaminate an oiled sample for

radiocarbon dating).  Coastal prehistoric sites could also be damaged by spill cleanup operations

(e.g., by destroying fragile artifacts and disturbing the provenance of artifacts and site features).

C.7 Coastal Habitats and Protected Areas

Coastal habitats in the northeastern Gulf of Mexico that may be affected by oil and gas activities

are described in recent EISs (MMS, 2007b, 2008) and in a literature review by Collard and Way

(1997).  Coastal habitats inshore of the project area include barrier beaches and dunes,

wetlands, and submerged seagrass beds.  Generally, most of the northeastern Gulf is fringed by

barrier beaches, with wetlands and/or submerged seagrass beds occurring in sheltered areas

behind the barrier islands and in estuaries.

Due to the distance from shore, the only IPF associated with routine activities in the lease area

that potentially may affect beaches and dunes, wetlands, seagrass beds, coastal wildlife refuges,

wilderness areas, or any other managed or protected coastal area is related to support vessel

traffic.  The support bases at Fourchon, Louisiana are not in wildlife refuges or wilderness areas.  

Potential impacts of support vessel traffic are addressed briefly below.

A small fuel spill in the lease area would be unlikely to affect coastal habitats, as the lease area is

143 miles (230 km) from the nearest shoreline (Louisiana).  As explained in Section A.9.2, a small

fuel spill would not be expected to make landfall or reach coastal waters prior to breaking up.
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Impacts of Support Vessel Traffic

For OCS activities in general, support operations, including crew boats and supply boats, may

have a minor incremental impact on coastal habitats.  Over time with a large number of vessel

trips, vessel wakes can erode shorelines along inlets, channels, and harbors.  Support

operations, including crew boats and supply boats as detailed in EP Section K, may have a minor

incremental impact on coastal habitats or protected areas.  Impacts will be minimized by

following the speed and wake restrictions in harbors and channels.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on coastal habitats are discussed in recent EISs (MMS, 2007b, 2008).  

Coastal habitats inshore of the project area include barrier beaches and dunes, wetlands, and

submerged seagrass beds.  For this EP, there are no unique site‐specific issues with respect to

coastal habitats.

The revised OSRA modeling summarized in Table 3 predicts that during winter there is a

17% probability of oil from a spill in the lease area reaching shorelines in Texas within 120 days,

and a 14% probability in spring of oil reaching Louisiana shorelines within 120 days.

The shorelines within the geographic range predicted by the OSRA modeling (Table 3) include

extensive barrier beaches and wetlands, with submerged seagrass beds occurring in sheltered

areas behind the barrier islands and in estuaries.  NWRs and other protected areas along the

coast are discussed in a recent lease sale EIS (MMS, 2007b) and Anadarko’s OSRP.  Coastal and

near coastal wildlife refuges, wilderness areas, and State and National parks within the

geographic range of the potential shoreline contacts after 120 days are presented in Table 6.

Table 6. Wildlife refuges, wilderness areas, and State and National parks within the geographic

range of the potential shoreline contacts after 120 days (From: BOEMRE, 2011a).

County or Parish Wildlife Refuge, Wilderness Area, or

State/National Park

Cameron County, Texas

Lower Rio Grande Valley National Wildlife Refuge

Laguna Atascosa National Wildlife Refuge

Padre Island National Seashore

Isla Blanca Park

Andy Bowie County Park  

Laguna Madre Estuarine and Coastal Marine Area

Willacy County, Texas

Lower Rio Grande Valley National Wildlife Reserve

Laguna Atascosa National Wildlife Reserve  

Padre Island National Seashore

Laguna Madre Estuarine And Coastal Marine Area

Kenedy County, Texas Padre Island National Seashore

Laguna Madre Estuarine and Coastal Marine Area

Kleberg County, Texas Padre Island National Seashore

Laguna Madre Estuarine and Coastal Marine Area

Nueces County, Texas

Laguna Madre Estuarine and Coastal Marine Area

Mustang Island State Park

Lake Corpus Christi State Park

Port Aransas Park

Mission‐Aransas National Estuarine Research Reserve

Aransas County, Texas  

Mission‐Aransas National Estuarine Research Reserve

Aransas National Wildlife Refuge

Goose Island State Park
Table 6.  (Continued.)

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County or Parish Wildlife Refuge, Wilderness Area, or

State/National Park

Calhoun County, Texas

Mission‐Aransas National Estuarine Research Reserve

Aransas National Wildlife Refuge

Matagorda Island State Park

Guadalupe Delta Wildlife Management Area

Welder Flats Coastal Preserve

Matagorda County, Texas  

Big Boggy National Wildlife Refuge

Aransas National Wildlife Refuge

Mad Island Wildlife Management Area

San Bernard National Wildlife Refuge

Brazoria County, Texas

San Bernard National Wildlife Refuge

Peach Point Wildlife Management Area

Brazoria National Wildlife Refuge

Christmas Bay Coastal Preserve and Christmas Bay State Park  

Galveston County, Texas

Galveston Island State Park

Brazoria National Wildlife Refuge

Apffel Park

Seawolf Park

Old Fort Travis Park

Atkinson Island Wildlife Management Area

Ft. Anahuc Park

Anahuac National Wildlife Refuge

Mcfaddin National Wildlife Refuge

Jefferson County, Texas  

Mcfaddin National Wildlife Refuge

Sea Rim State Park

Murphree Wildlife Management Area

Texas Point National Wildlife Refuge

Cameron Parish, Louisiana  

Sabine National Wildlife Refuge

Cameron Prairie National Wildlife Refuge

Lacassine National Wildlife Refuge

Little Pecan Island Natural Area

Peveto Woods Natural Area

Lower Neches Wildlife Management Area

Rockefeller Wildlife Management Area

Vermilion Parish, Louisiana Louisiana Rockefeller Wildlife Management Area

Paul J. Rainey Wildlife Management Area

Plaquemines Parish, Louisiana  

Salvador Wildlife Management Area

Jean Lafitte National Historical Park and Preserve

Delta National Wildlife Refuge

Pass‐a‐Loutre Wildlife Management Area

Breton National Wildlife Refuge

St. Bernard State Park

The level of impacts from oil spills on coastal habitats depends on many factors, including the oil

characteristics, the geographic location of the landfall, and the weather and oceanographic

conditions at the time (MMS, 2007b).  Oil that makes it to beaches may be either liquid

weathered oil, an oil‐and‐water mousse, or tarballs (MMS, 2007b).  Oil is generally deposited on

beaches in lines defined by wave action at the time of landfall.  Oil that remains on the beach

will thicken as its volatile components are lost.  Thickened oil may form tarballs or aggregations

that incorporate sand, shell, and other materials into its mass.  Tar may be buried to varying

depths under the sand.  On warm days, both exposed and buried tarballs may liquefy and ooze.  

Oozing may also serve to expand the size of a mass as it incorporates beach materials.  Oil on
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beaches may be cleaned up manually, mechanically, or both.  Some oil can remain on the beach

at varying depths and may persist for several years as it slowly biodegrades and volatilizes.

Wetlands are highly sensitive to oiling.  The MMS (2007b) predicted that for every 50 bbl of oil

contacting wetlands, approximately 2.7 ha (6.7 ac) of wetland vegetation will experience

dieback.  Thirty percent of these damaged wetlands are assumed to recover within 4 years, and

85% within 10 years.  About 15% of the contacted wetlands are expected to be converted

permanently to open‐water habitat.  The critical concentration of oil is that concentration above

which impacts to wetlands will be long‐term and recovery will take longer than two growing

seasons, and which causes plant mortality and some permanent wetland loss.  Critical

concentrations of various oils are expected to vary broadly for wetland types and wetland plant

species.  Louisiana wetlands are assumed to be more sensitive to oil contact than elsewhere in

the Gulf because of high cumulative stress (MMS, 2007b).  In addition to the direct impacts of

oil, cleanup activities in marshes may accelerate rates of erosion and retard recovery rates,

which have been reported to require from years to decades following a spill (MMS, 2007b).

C.8 Socioeconomic and Other Resources

C.8.1 Recreational and Commercial Fishing

BOEMRE has reexamined the analysis for recreational and commercial fishing presented in

MMS (2007b, 2008) based on additional information and in consideration of the Macondo spill.  

No new information was found that would alter the potential impacts on commercial fishing

(BOEMRE, 2011a,b).

The main commercial fishing activity in deep waters of the northern Gulf of Mexico is pelagic

longlining for tunas, swordfishes, and other billfishes (Continental Shelf Associates, Inc., 2002).  

Pelagic longlining has occurred historically in the project area, primarily during spring and

summer.  In August 2000, the Federal government closed two areas in the northeastern Gulf of

Mexico to longline fishing (65 FR 47214, 1 August 2000).  The lease is outside of the closure

areas.

Longline gear consists of monofilament line deployed from a moving vessel and generally

allowed to drift for 4 to 5 hours (Continental Shelf Associates, Inc., 2002).  As the mainline is put

out, baited leaders and buoys are clipped in place at regular intervals.  It takes 8 to 10 hours to

deploy a longline and about the same time to retrieve it.  Longlines are often set near

oceanographic features such as fronts or downwellings, with the aid of sophisticated on‐board

temperature sensors, depth finders, and positioning equipment.  Vessels typically are 10 to 30 m

(33 to 98 ft) long, and their trips last from about 1 to 3 weeks.  The main Gulf of Mexico

homeports for longlining vessels are in Louisiana (Dulac and Venice) and Florida (Destin,

Madeira Beach, and Panama City).

It is unlikely that any commercial fishing activity other than longlining occurs at or near the

project area.  Benthic species targeted by commercial fishers occur on the upper continental

slope, well inshore of the project area.  Royal red shrimp are caught by trawlers in water depths

of about 250 to 550 m (820 to 1,804 ft).  Tilefish are caught by bottom longlining in water

depths from about 165 to 450 m (540 to 1,476 ft) (Continental Shelf Associates, Inc., 2002).

Most recreational fishing activity in the region occurs in water depths less than 200 m (656 ft)

(Continental Shelf Associates, Inc., 1997, 2002).  In deeper water, the main attraction to
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recreational fishers would be petroleum rigs offshore Texas and Louisiana.  Due to the distance

from shore, it is unlikely that recreational fishing activity is occurring in the lease area.

The only routine IPF potentially affecting fisheries is drilling rig presence (including noise and

lights).  Two potential accidents are also addressed below – a small fuel spill and a large oil spill

(WCD).

Impacts of Drilling Rig Presence

There is a slight possibility of pelagic longlines becoming entangled in the drilling rig.  For

example, in January 1999, a portion of a pelagic longline snagged on the acoustic Doppler

current profiler of a drillship working in the Gulf of Mexico (Continental Shelf Associates, Inc.,

2002).  The line was removed without incident.  Generally, longline fishers use radar and are

aware of offshore structures and ships when placing their sets.  Therefore, little or no impact on

pelagic longlining is expected.

Because it is unlikely that any recreational fishing activity is occurring in the project area, no

adverse impacts are anticipated.  Other factors such as effluent discharges are likely to have

negligible impacts on commercial or recreational fisheries due to rapid dispersion, the small

area of ocean affected, and the intermittent nature of the discharges.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially mitigate and reduce the potential for impacts.  EP Section H

provides detail on spill response measures.  Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

Pelagic longlining activities in the lease area, if any, could be interrupted in the event of a small

fuel spill.  The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.  Fishing activities could be

interrupted due to the activities of response vessels operating in the lease area.  A small fuel

spill would not affect coastal water quality because the spill would not be expected to make

landfall or reach coastal waters prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on fishing activities are discussed in recent EISs (MMS, 2007b, 2008).  For

this EP, there are no unique site‐specific issues with respect to this activity.

Pelagic longlining activities in the lease area and other fishing activities in the northern Gulf of

Mexico could be interrupted in the event of a large oil spill.  A spill may or may not result in

fishery closures, depending on the duration of the spill, the oceanographic and meteorological

conditions at the time, and the effectiveness of spill response measures.  The recent Macondo

spill provides information about the maximum potential extent of fishery closures in the event

of a large oil spill in the Gulf of Mexico (NMFS, 2010d).  At its peak on 12 July 2010, closures

encompassed 217,821 km2 (84,101 mi2

), or 34.8% of the U.S. Gulf of Mexico EEZ.
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C.8.2 Public Health and Safety

There are no IPFs associated with routine operations that are expected to affect public health

and safety.  Impacts of a small fuel spill and a large oil spill (WCD) are addressed below.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially alleviate the potential for impacts.  EP Section H provides detail

on spill response measures.

A small fuel spill would not have any impacts on public health and safety because it would affect

only a small area of the open ocean 143 miles (230 km) from the nearest shoreline (Louisiana)

and nearly all of the diesel fuel would evaporate or disperse naturally within 24 hours.  

Response crews would be equipped with appropriate safety equipment to avoid injury and

health effects.  A small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up (see Section A.9.2).

Impacts of a Large Oil Spill (WCD)

In the event of a large spill from a blowout, the main safety and health concerns are those of the

offshore personnel involved in the incident and those responding to the spill.  The drilling rig

maintains a Shipboard Oil Pollution Emergency Plan as required under MARPOL 73/78.

Depending on the spill rate and duration, the physical/chemical characteristics of the oil,

meteorological and oceanographic conditions at the time, and the effectiveness of spill response

measures, the public could be exposed to oil on the water and along the shoreline, including

skin contact or breathing VOCs.  Crude oil is a highly flammable material, and any smoke or

vapors from a crude oil fire can cause irritation, and in large quantities may pose a health

hazard.

Data from the recent Macondo spill provide relevant information about the types of health

issues that may occur in the event of a large oil spill (Centers for Disease Control and Prevention,

2010a).  Wildlife cleaning  and rehabilitation workers have reported concerns including scrapes

and cuts, itchy or red skin or rash, and symptoms of headache or feeling faint, dizzy, or fatigued.  

Hand, shoulder, or back pain was also reported by some wildlife‐cleaning workers.  Personnel

working on offshore vessels or providing direct oversight to offshore vessels, including

USCG personnel, civilian contractors, and other responders who were exposed to oil and

dispersants, had a 7 to 12 times higher prevalence of upper respiratory symptoms and cough

than those not exposed (Centers for Disease Control and Prevention, 2010b).  Another potential

occupational hazard for spill response workers in general was heat stress from work in a hot and

humid environment.  Initial symptoms from cleanup workers who sought medical care in

Louisiana were typical of acute exposure to hydrocarbons or H2S such as headaches, dizziness,

nausea, vomiting, cough, respiratory distress, and chest pain (Solomon and Janssen, 2010).

C.8.3 Employment and Infrastructure

There are no IPFs associated with routine operations that are expected to affect employment

and infrastructure.  The project involves drilling with support from existing shorebase facilities in

Louisiana.  No new or expanded facilities will be constructed, and no new employees are
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expected to move permanently into the area.  The project will have a negligible impact on

socioeconomic conditions such as local employment, existing offshore and coastal infrastructure

(including major sources of supplies, services, energy, and water), and minority and lower

income groups.  Impacts of a small fuel spill and a large oil spill (WCD) are addressed below.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially mitigate and reduce the potential for impacts.  EP Section H

provides detail on spill response measures.  Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill that is dissipated within a few days would have little or no economic impact, as

the spill response would use existing facilities, resources, and personnel.

Impacts of a Large Oil Spill (WCD)

Potential socioeconomic impacts of an oil spill are discussed in recent EISs (MMS, 2007b, 2008).  

For this EP, there are no unique site‐specific issues with respect to employment and coastal

infrastructure.  A large spill could cause economic impacts in several ways: it could result in

extensive fishery closures that put fishermen out of work; it could result in temporary

employment as part of the response effort; it could result in adverse publicity that affects

employment in coastal recreation and tourism industries; and it could result in another

suspension of OCS drilling activities, including service and support operations that are an

important part of local economies.

In addition to the analyses presented by MMS (2007b, 2008) and BOEMRE (2011a,b), a recent

study explored the economic impacts of the Macondo spill on oil and gas industry employment

due to suspension of deepwater drilling (Inter‐Agency Economic Report, 2010).  The study

indicates that during the moratorium, the number of oil industry workers in the Gulf of Mexico

fell by about 2,000 and may have indirectly caused a temporary loss of 8,000 to 12,000 jobs

along the Gulf Coast.  Total spending by drilling operators is estimated to have declined by

$1.8 billion over a 6‐month period; this direct reduction in spending affected employment in the

industries that supply the Gulf drilling industry and in all other industries affected by declines in

consumer and business spending (Inter‐Agency Economic Report, 2010).

C.8.4 Recreation and Tourism

BOEMRE has reexamined the analyses for recreation and tourism presented in MMS (2007b,

2008) based on additional information and in consideration of the Macondo oil spill event.  No

new information was found that would alter the potential impacts on recreation and tourism

(BOEMRE, 2011a,b).

There are no known recreational uses of the lease area.  Recreational resources and tourism in

coastal areas would not be affected by any routine activities due to the distance from shore.  

Compliance with BSEE NTL 2012‐G01 will minimize the chance of trash or debris being lost

overboard from the drilling rig and subsequently washing up on beaches.
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Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer.  In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially help mitigate and reduce the potential for impacts.  

EP Section H provides detail on spill response measures.  Given the open ocean location of the

lease area, the duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in the lease area would be unlikely to affect recreation and tourism.  There are

no known recreational or tourism activities occurring in the lease area, and as explained in

Section A.9.2, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up.

Impacts of a Large Oil Spill (WCD)

Potential impacts of an oil spill on recreation and tourism are discussed in recent EISs

(MMS, 2007b, 2008).  For this EP, there are no unique site‐specific issues with respect to these

impacts.

Impacts on recreation and tourism would vary depending on the duration of the spill and its fate

including the effectiveness of response measures.  A large spill that reached coastal waters and

shorelines could adversely affect recreation and tourism by contaminating beaches and

wetlands, resulting in negative publicity that encourages people to stay away.  Based on the

revised OSRA modeling (BOEMRE, 2011a) as summarized in Section A.9.3 (Table 3), there is a

17% probability in winter of oil from a spill in the lease area reaching shorelines in Texas and a

14% chance in spring of contacting shorelines in Louisiana within 120 days.   

In addition to the analysis presented by MMS (2007b, 2008), recent and ongoing studies have

explored the economic impacts of the Macondo spill including tourism and “brand” damage

(IEM, 2010; Oxford Economics, 2010).  The U.S. Travel Association has estimated the economic

impact of the Macondo spill on tourism across the Gulf Coast over a 3‐year period at

$22.7 billion (Oxford Economics, 2010).

C.8.5 Land Use

Land use along the northern Gulf Coast is discussed in recent lease sale EISs (MMS, 2007b,

2008).  There are no routine IPFs potentially affecting land use.  The project will use existing

onshore support facilities in Louisiana.  The land use at the existing shorebase sites is industrial.  

The project will not involve any new construction or changes to existing land use and, therefore,

will not have any impacts.  Levels of boat and helicopter traffic, as well as demand for goods and

services including scarce coastal resources, will represent a small fraction of the level of activity

occurring at the shorebases.

A large oil spill (WCD) is the only relevant accident IPF.  A small fuel spill would not have any

impacts on land use, as the response would be staged out of existing shorebases and facilities.

Impacts of a Large Oil Spill (WCD)

The initial response for a large oil spill would be staged out of existing facilities, with no effect on

land use.  A large spill could have limited temporary impacts on land use along the coast if

additional staging areas were needed.  For example, during the Macondo spill, temporary
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staging areas were established in Louisiana, Mississippi, Alabama, and Florida for spill response

and cleanup efforts.  In the event of a large spill in the lease area, similar temporary staging

areas could be needed.  These areas would eventually return to their original use as the

response is demobilized.

C.8.6 Other Marine Uses

The lease area is located within the Eglin Water Test Area (EWTA) 3 Military Warning Area.  

Anadarko will comply with BOEM requirements and lease stipulations to avoid impacts on uses

of the area by military vessels and aircraft.  There are no existing wells, pipelines, or platforms

within LL 621.  The closest existing infrastructure to the proposed wellsites are three exploration

wells, a gas pipeline, and an umbilical approximately 16 miles (26 km) north‐northwest in LL 399.

There are no IPFs from routine project activities that are likely to affect other marine uses of the

lease area.  A large oil spill (WCD) is the only relevant accident IPF.  A small fuel spill would not

have any impacts on other marine uses because spill response activities would be mainly within

the lease area and the duration would be brief.

Impacts of a Large Oil Spill (WCD)

An accidental spill would be unlikely to significantly affect shipping or other marine uses.  The

blocks are not located within any USCG‐designated fairway or shipping lane.  In the event of a

large spill requiring numerous response vessels, coordination would be required to manage the

vessel traffic for safe operations.  Anadarko will comply with BOEM requirements and lease

stipulations to avoid impacts on uses of the area by military vessels and aircraft.

In the event of a large spill requiring numerous vessels in the area, coordination would be

required to ensure that no anchoring or seafloor‐disturbing activities occur near the existing

pipelines and flowlines.

D.  Environmental Hazards

D.1 Geologic Hazards

The Site Clearance Letter prepared by GEMS (2009) concluded that the wellsites are free of any

significant geological hazards and are suitable for the proposed activities.  See EP Section C for

supporting geological and geophysical information.

D.2 Severe Weather

Under most circumstances, weather is not expected to have any effect on the proposed

activities.  Extreme weather, including high winds, strong currents, and large waves, was

considered in the design criteria for the drilling rigs under consideration for this project.  High

winds and limited visibility during a severe storm could disrupt support activities (vessel and

helicopter traffic) and make it necessary to suspend some activities on the drilling rig for safety

reasons until the storm or weather event passes.  In the event of a hurricane, procedures as

outlined in the Hurricane Evacuation Plan would be adhered to.
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D.3 Currents and Waves

Metocean conditions such as sea states, wind speed, ocean currents, etc. will be continuously

monitored.  Under most circumstances, physical oceanographic conditions are not expected to

have any effect on the proposed activities.  Strong currents (e.g., caused by Loop Current eddies

and intrusions) and large waves were considered in the design criteria for the drilling rigs under

consideration for this project.  High waves during a severe storm could disrupt support activities

(i.e., vessel and helicopter traffic) and make it necessary to suspend some activities on the

drilling rig for safety reasons until the storm or weather event passes.

E.  Alternatives

No formal alternatives were evaluated in this EIA for an EP.  However, various technical and

operational options, including the location of the wellsites and the selection of a drilling unit,

were considered by Anadarko in developing the proposed action.

F.  Mitigation Measures

The proposed action includes numerous mitigation measures required by laws, regulations, and

BOEM lease stipulations and NTLs.  The project will comply with all applicable Federal, State,

and local requirements concerning air pollutant emissions, discharges to water, and solid waste

disposal.  All project activities will be conducted under guidance by Anadarko’s OSRP and will

include the measures described in EP Section H.

G.  Consultation

No persons or agencies were consulted during the preparation of this EIA.

H.  Preparers

The EIA was prepared by CSA International, Inc.  Contributors included

 M. John Thompson (Senior Scientist);

 Neal Phillips, Ph.D. (Senior Scientist);

 Luis Lagera, Jr., Ph.D. (Senior Scientist);

 Keith VanGraafeiland (GIS/Remote Sensing Specialist);

 Kristen L. Metzger (Library and Information Services Director); and

 Kim Dunleavy (Technical Editor).
Lloyd Ridge Block 621 October 2011

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O 

ADMINISTRATIVE INFORMATION 

(a) Proprietary Information 

Proprietary copies of this plan contain information not available to the public and include 

structure maps, seismic information, cross sections, depths of wells, etc. 

(b) Bibliography 

Shallow Hazards Report 

Addendum to Site Clearance Letters for Proposed Wellsites A and B, Lloyd Ridge Block 

621 

Final Sale Package for Central Gulf of Mexico Lease Sale 208