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-09714

Type - Initial Exploration Plan

Lease(s) - OCS-G33755 Block - 738 Mississippi Canyon Area

OCS-G33757 Block - 782 Mississippi Canyon Area

Operator - Noble Energy, Inc.

Drill & Complete - MC 738 A, B, MC 782 A, B, C, D

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.

Mohammad Ashfaq

Plan Coordinator

Description -

Rig Type -

Subject:

From:

June 11, 2013


PUBLIC COPY

April 9, 2013

Initial Exploration Plan

Lease OCS-G 33755 & 33757

Mississippi Canyon 738 & 782

Prospect Name: Dantzler

Offshore: Louisiana and Alabama

Submitted by:

Noble Energy, Inc.

100 Glenborough Drive

Suite 100

Houston, Texas 77067

Estimated start up date: July 28, 2013
Table of Contents

Noble Energy, Inc.

Initial Exploration Plan

Lease OCS-G 33755 & 33757

Mississippi Canyon 738 & 782

A. Plan Contents

a. Plan Summary

b. Plan Information Form

c. Location

d. Safety and Pollution Prevention Features

e. Storage Tanks and/or Production Vessels

f. Additional Measures

B. General Information

a. Applications and Permits

b. Drilling Fluids

c. New or Unusual Technologies

d. Bonding Statement

e. Oil Spill Financial Responsibility (OSFR)

f. Deepwater Well Control Statement

g. Blowout Scenario

C. Geological and Geophysical Information

a. Geologic Description

b. Structure Contour Maps

c. Interpreted 3-D Seismic Lines

d. Geological Structure Cross Section

e. Shallow Hazards Report

f. Shallow Hazards Assessment

g. High Resolution Seismic Lines

h. Stratigraphic Column

i. Time vs. Depth Table

D. Hydrogen Sulfide (H2S) Information

a. Concentration

b. Classification

E. Biological, Physical, and Socioeconomic Information

a. Chemosynthetic Communities Report

b. Topographic Features Map

c. Topographic Features Statement (Shunting)

d. Live Bottoms (Pinnacle Trend) Map

e. Live Bottoms (Low Relief) Map

f. Potentially Sensitive Biological Features

g. Remotely Operated Vehicle (ROV) Monitoring Survey Plan

h. Threatened and Endangered Species Information, Critical Habitat, and Marine

Mammal Information

i. Archaeological Report
F. Waste and Discharge Information

a. Projected Generated Wastes & Projected Ocean Discharges

G. Air Emissions Information

a. Emissions Worksheets and Screening Questions

H. Oil Spill Information

a. Oil Spill Response Planning

b. Spill Response Sites

c. OSRO Information

d. Worst-case Scenario Comparison

e. Oil Spill Response Discussion

I. Environmental Monitoring Information

a. Monitoring Systems

b. Incidental Takes

c. Flower Garden Banks National Marine Sanctuary

J. Lease Stipulation Information

K. Support Vessels and Aircraft Information

a. General

b. Diesel Oil Supply Vessels

c. Solid and Liquid Wastes Transportation

d. Vicinity Map

L. Onshore Support Facilities Information

a. General

b. Support Base Construction or Expansion

c. Waste Disposal

M. Coastal Zone Management Act (CZMA) Information

N. Environmental Impact Analysis (EIA)

O. Administrative Information

a. Exempted Information Description

b. Bibliography
Section A

Plan Contents

A. Plan Summary

Noble Energy, Inc. proposes to drill and complete six well in Mississippi Canyon Blocks 738 and 782

utilizing a dynamically positioned semisubmersible rig and a subsea BOP. The anticipated spud date of

the first well is July 28, 2013. Noble anticipates it will take approximately 86 days to drill and 70 days

to complete each well. If commercial quantities of hydrocarbons are discovered, a Development

Operations Coordination Document will be submitted for approval.

B. Plan Information Form

See attached OCS Plan Information Form – Form BOEM-137, included as Attachment A-1.

C. Location

Included as Attachment A-2 is a location map depicting the proposed surface locations of the new wells.

Attachment A-3 is a bathymetry map showing the water depths at the surface location of each proposed

well. Attachment A-4 is proprietary information.

D. Safety and Pollution Prevention Features

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

be made part of each Application for Permit to Drill.

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

prevention equipment as described in Title 30 CFR Part 250, Subparts C, D, E, and G; and as further

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

Environmental Protection Agency and the U.S. Coast Guard. Appropriate life rafts, life jackets, ring

buoys, etc., will be maintained on the facility at all times.

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

areas to collect all contaminants and debris.

E. Storage Tanks and/or Production

Vessels All facility tanks of 25 barrels or more.

Type of Storage

Tank Type of Facility Tank Capacity(bbls)

Number

of Tanks

Total

Capacity

(bbls)

Fluid

Gravity

(API)

Fuel Oil (Marine

Diesel) DP Semisubmersible

3,461 2 6,922 32.4°

4,634 2 9,268 32.4°

Total 16,190

F. Additional Measures

Noble does not propose additional safety, pollution prevention, or early spill detection measures beyond

those required by 30 CFR 250.

Noble Energy, Inc. Page A-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)







a

aa

)

)

)

738

782

A

A

B

C

OCS-G-33755

OCS-G-33757

1 1BP

25593' 27316'

Y=10,264,320'

Y=10,232,640'

Y=10,248,480'

X=1,219,680'

X=1,235,520'

782 'A' S.L. X=1,224,943'

Y=10,247,759'

LAT. 28° 13' 59.05"N

LON. 88° 17' 26.43"W

WD 6576'

782 'B' S.L. X=1,226,029'

Y=10,245,555'

LAT. 28° 13' 37.34"N

LON. 88° 17' 14.02"W

WD 6560'

782 'C' S.L. X=1,224,265'

Y=10,238,900'

LAT. 28° 12' 31.25"N

LON. 88° 17' 32.95"W

WD 6542'

738 'A' S.L. X=1,224,346'

Y=10,250,202'

LAT. 28° 14' 23.18"N

LON. 88° 17' 33.39"W

WD 6572'

738 'A' S.L. 1722' FSL

4666' FWL

782 'A' S.L. 721' FNL

5263' FWL

782 'B' S.L. 2925' FNL

6349' FWL

782 'C' S.L. 6260' FSL

4585' FWL

Proposed well locations

Coordinates

Public

Information

D

B

738 'B' S.L. X=1,224,427'

Y=10,250,134'

LAT. 28° 14' 22.51"N

LON. 88° 17' 32.48"W

WD 6572'

738 'B' S.L. 1654' FSL

4747' FWL

782 'D' S.L. X=1,224,918'

Y=10,247,903'

LAT. 28° 14' 0.47"N

LON. 88° 17' 26.72"W

WD 6576'

782 'D' S.L. 577' FNL

5238' FWL

DEEP WATER

BUSINESS UNIT

MISSISSIPPI CANYON 738/782

LOUISIANA

LOCATION PLAT

GEOL./GEOP.: Staff C.I.:

FILENAME: DATE: 1/2013

0 1,000 2,000 4,000 6,000 8,000

® Feet

Projection: UTM Zone 16 North

Datum: NAD 27

Distance Units: US Survey Feet
a

aa

)

)

)

738

782

A

A

B

C

OCS-G-33755

OCS-G-33757

1 1BP

25593' 27316'

Public

Information

6250'

6500'

6750'

6750'

7000'

D

B

DEEP WATER

BUSINESS UNIT

MISSISSIPPI CANYON 738/782

LOUISIANA

BATHYMETRY PLAT

GEOL./GEOP.: Staff C.I.: 50’

FILENAME: DATE: 1/2013

0 1,000 2,000 4,000 6,000 8,000

® Feet Projection: UTM Zone 16 North

Datum: NAD 27

Distance Units: US Survey Feet

Proposed well locations

738 'A' S.L. 1722' FSL

4666' FWL

738 'B' S.L. 1654' FSL

4747' FWL

782 'A' S.L. 721' FNL

5263' FWL

782 'B' S.L. 2925' FNL

6349' FWL

782 'C' S.L. 6260' FSL

4585' FWL

782 'D' S.L. 577' FNL

5238' FWL
Section B

General Information

A. Applications and Permits

No additional applications or permits are required to conduct the activities proposed herein.

B. Drilling Fluids –

Type of Drilling Fluid Estimated Volume of Drilling

Fluid to be used per Well

Water-based Please see table in Section F

Page F-1

Synthetic-based Please see table in Section L

Page L-2

C. New or Unusual Technology

Noble does not propose to use any new or unusual technology to carry out the proposed exploration

activities.

D. Bonding Statement

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

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

General Lease Surety Bonds;" and NTL No. 2008-N07, "Supplemental Bond Procedures".

E. Oil Spill Financial Responsibility (OSFR)

Noble Energy, Inc., BOEM company number 02237, has demonstrated oil spill financial responsibility

for the facilities proposed in this EP according to 30 CFR Part 253; and NTL No. 2008-N05, "Guidelines

for Oil Spill Financial Responsibility for Covered Facilities".

F. Deepwater Well Control Statement

Noble Energy, Inc., BOEM company number 02237, has the financial capability to drill a relief well and

conduct other emergency well control operations.

G. Blowout Scenario

The NTL 2010-N06, worst case discharge package, is included as "Attachment B­1".

Noble Energy, Inc. Page B-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
1

WCD Discharge Discussion

OCS-G33757 Operator – Noble Energy, Inc.

MC 782-A, Dantzler Prospect

Introduction

Noble Energy Inc. is planning to drill the Dantzler Prospect, MC 782 No.1well, to a depth of

21,584’ MD to test the Middle Miocene sands updip of the Chevron Caterpillar Deep well (OCSG16648 MC 782 No. 1). Noble Energy, Inc. has calculated a Worst Case Discharge rate based on

mapping the sands found in the Caterpillar well to the proposed location for the Dantzler

prospect. The calculated worst case discharge is 173,214 BOPD + no water. Noble Energy, Inc.

has the resources to respond to the estimated Worst Case Discharge rate.

WCD Hole Section

The MC 782-A WCD (NTL – 06) application is designed for the exploration well. The well

consists of eight hole sections to a proposed total depth of 21,584’ MD.

WCD Geological Input

The WCD model was built using values based on well control from local fields and dry holes.

Interpretation of lithology was based on both seismic character (amplitude response) and seismic

ties to wells with lithology data. Seismic lines were tied to the following local wells: Chevron

MC 782 #1 (Caterpillar Deep), Amoco MC 739 #1 (Hilbert), BP MC 696 #1 (Blind Faith) and

Shell MC 608 #1 (East Anstey).

WCD Engineering Input

The petrophysical and fluid data used in the WCD calculations were based on both public data

and proprietary analog data in the area. The rock values were calculated from the closest offset

well log of Chevron MC 782 No. 1, also known as Caterpillar Deep.

Dantzler MC 782 # 1 WCD Calculation Results

Noble Energy, Inc. used a commercial available nodal analysis program (Prosper) to calculate a

WCD value of 173,214 BOPD + no water.

Description of the Drilling Blowout Scenario

The MC 782-A WCD is based on a drilling blowout scenario whereby the well has been drilled to

TD and it is assumed that the drill pipe will be out of the hole and the drilling riser is removed

allowing the worst case discharge fluid to exit the well at the subsea wellhead. In this WCD

scenario, the assumption is the well will produce unrestricted from the open hole section to the

wellhead with a sea water gradient as backpressure at the wellhead, and expects a failure of the

closing of the blowout preventers (BOP) and the absence of a riser.
2

Duration of the Worst Case Discharge

The duration of the WCD is dependent on the characteristics of the blow out. The WCD will

persist until the well is contained, a relief well is drilled, or the well bridges over due to wellbore

instability.

Scenarios exist in which the duration of the WCD has the potential to flow from hours to months

depending on the condition of the well at the time of the discharge as outlined below:

 The well could bridge over due to wellbore instability which should happen relatively

early in the WCD scenario.

 Containment blowout preventer equipment (BOPE) is installed and closed using a

prescribed procedure shutting in the well and eliminating the discharge. This would

require between several weeks to accomplish, provided no debris removal is required.

 Twisted riser material may need to be removed prior to any containment equipment

installation, which could take considerable time depending on the amount and complexity

of debris. It could take several weeks to a few months to clear a connection for the BOPE

to eliminate fluid releases.

 If all intervention attempts are unsuccessful, the well could discharge until intercepted and

killed by a relief well intervention. The estimated time to drill a relief well is

approximately four months. The estimated worst case volume discharge in the worst case

scenario described above is 20.8 million barrels.

In summary, the WCD duration may be short lived if it bridges over, last several days until the

well is contained, or discharge for several months until the relief well kills the discharging well.

Noble Energy, Inc. has recently participated in an unannounced offshore WCD drill with BSEE

and successfully capped a deepwater well in one week which includes several days of weather

downtime.

Potential of Open Hole to Bridge Over

Due to the unrestricted flow of a WCD scenario, the well has the potential to experience a

downhole rock failure. The primary failure mechanism would be wellbore instability caused by

the reduced wellbore pressure. The in situ stresses that exist in the reservoir rock are held in

place by the hydrostatic pressure of the weighted drilling fluid in the wellbore. If the wellbore

pressure is reduced, the high in situ stresses are no longer opposed by the weighted drilling fluid

and the in situ rock may fail and collapse into the wellbore causing the wellbore to bridge over

where the failed rock fragments accumulate and lodge downhole to prevent the well discharge

from continuing.
3

Likelihood for Surface Intervention to Stop Blowout

There is a high likelihood that a combined surface and subsea intervention would stop a blowout

of the MC 782-A well. Noble Energy has access to and can deploy surface and subsea

containment resources. Clean Gulf Associates (CGA) has the capability to provide efficient

mobilization of necessary equipment and procedures to effectively mitigate numerous blowout

scenarios.

Availability of Drilling Rig for a Relief Well

In the event of a WCD, Noble Energy has identified several dynamically positioned (DP) rigs that

are capable of drilling the MC 782-A relief well to the appropriate depth and in 6,576’ of water.

Depending on the activity and location of an equivalent rig at the time of the WCD, it may require

several weeks before the rig is on location ready to spud the relief well.

Estimated Time to Drill a Relief Well

A deepwater drilling rig capable of drilling in +/- 6,600’ of water must be utilized for a relief

well. In this scenario, drilling a relief well from a nearby platform is not feasible. The estimated time 

to drill a relief well is 120 days which allows 2 weeks for securing a DP rig and mobilize it to the lease.

Measures for Blowout Prevention

Certain measures will be taken to prevent and reduce the likelihood of a blowout as described in

the WCD discharge scenario. The blowout prevention measures provide additional assurance in

improving the safety of offshore oil and gas drilling. Key measures taken for blowout prevention

include but are not limited to:

 Complying with all Federal rules and regulations: CFRs, NTLs, and Final Rules.

 Following provisions in API RP 65-Part 2 and API RP 53.

 Utilizing Noble’s management systems: Global Management System (GMS),

Safety and Environmental Management System (SEMS), Drilling Management

System (DMS), Management of Change (MOC), and/or appropriate bridging

documents to contractor’s Safety Management Systems.

 Utilizing established well control practices, guidelines, and procedures.

 Certifying that the BOPE that is fit for purpose.

 Utilizing rig and equipment that is fit for purpose.

Early Intervention In the Event of a Blowout

Noble Energy has access to and can deploy surface and subsea containment resources to promptly

respond to a blowout or loss of well control. Noble Energy has access to the following through

the CGA:

 Subsea containment and capture equipment
4

 Subsea equipment to cut riser and perform various interventions

 Dispersant injection equipment

 Riser systems

 Remotely operated vehicles

 Capture vessels

 Support vessels

 Storage facilities

MC 782-A Containment

In the event of a WCD scenario blowout, the MC 782-A is designed to handle the worst-case shut

in pressure and maintain full integrity. This wellbore integrity will allow the HFRS 10k subsea

capping stack to be utilized for capping and killing the well in a timely manner.

Relief Well Arrangements

Noble Energy Inc. has taken additional measures for drilling a relief well to assist in conducting

early and effective intervention of a blowout. Noble Energy Inc. has selected relief well locations

with notional well designs to intercept the last drilling liner set prior to drilling the production

hole section. The team has assessed the tangibles, equipment, and services necessary to drill a

relief well and can source all of those requirements in the event of a blowout.

Summary

Noble Energy, Inc. calculates a Worst Case Discharge rate of 173,214 BOPD based on detailed

engineering calculations using geological and geophysical inputs from nearby offset wells. Noble

Energy, Inc. has the resources to respond to this Worst Case Discharge scenario in a timely

manner.
Section C

Geological and Geophysical Information

A. Geological Description

Proprietary Data

B. Structure Contour Map

Proprietary Data

C. Interpreted 3-D Seismic Lines

Proprietary Data

D. Geological Structure Cross-Section

Proprietary Data

E. Shallow Hazards Report

A shallow hazards survey was conducted over Mississippi Canyon 738 and 782. Locations included are

MC 738 A, MC 738 B, MC 782 A, MC 782 B, MC 782 C and MC 782 D.

F. Shallow Hazards Assessment

Utilizing the 3D seismic exploration data, a shallow hazards assessment was prepared for the proposed

surface locations, and is included as Attachment C-4. The shallow hazards assessment for the proposed

well locations are included as report “Shallow Hazards Assessment Dantzler Prospect, Block 738, 782

and Vicinity (OCS-G-33755 and OCS-G-33757)”, Project No. 27.2012-2526.

G. High-Resolution Seismic Lines

Proprietary Data

H. Stratigraphic Column

Proprietary Data

I. Time vs. Depth Table

Proprietary Data

Noble Energy, Inc. Page C-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
FUGRO GEOCONSULTING, INC.

Letter Report No. 27. 2012-2526-4

13 February 2013

Noble Energy, Inc.

100 Glenborough

Houston, Texas 77069

Attention: Mr. Bill Hobbs

Wellsite Clearance Letter

Proposed Wellsite MC 738-A

Block 738, Mississippi Canyon Area

OCS-G-33755

Introduction. Fugro GeoConsulting, Inc. (FGCI) was contracted by Noble Energy Inc. (Noble) to

prepare a wellsite clearance letter addressing shallow hazards for proposed Wellsite MC 738-A in

Block 738, Mississippi Canyon Area (OCS-G-33755). The proposed well is planned to be vertical through

the tophole section and will be drilled by a dynamically positioned rig. This letter is intended to address

specific seafloor and shallow geologic conditions within 3,000 ft of the proposed wellsite to the top of salt

reflector (about 3,579 ft BML). Shallow geologic conditions at the proposed wellbore are summarized on

the attached Tophole Prognosis Chart. Annotated data examples of the nearest 3D exploration seismic

survey lines, a sub-bottom profiler line, and four 1:12,000-scale charts showing the proposed wellsite are

included. The 1:12,000-scale illustrations include a water depth and seafloor features chart, a side-scan

sonar mosaic, a multibeam backscatter chart, and a sub-seafloor geologic features chart. A 2,000 ft radius

circle around the proposed wellsite is shown, as per Bureau of Ocean Energy Management (BOEM) Notice

to Lessees (NTL) 2009-G40. Please refer to Fugro Report No. 27.2012-2526, “Shallow Geohazards

Assessment, Dantzler Prospect, Blocks 738 and 782, Mississippi Canyon Area, Gulf of Mexico,” for a

comprehensive assessment of shallow geohazards within Blocks 738 and 782, and a complete list of

references used in this investigation. Please refer to C&C Technologies, Inc. Project No. 120578,

“Archaeological Assessment Report, Blocks 737, 738, 782 Mississippi Canyon Area, Gulf of Mexico,” for a

description of the AUV geophysical data used in this report, as well as a comprehensive archaeological

assessment.

3-D Seismic Survey Parameters. A pre-stack, time-migrated 3DX seismic data volume was used

for this assessment. The 3DX survey is a subset of the WesternGeco “E-Manatee” reprocessing effort

completed in August 2007 and is based in part on the “Mississippi Canyon Phase 11 (Ultra)” survey

acquired in 1997 in a north-south orientation with a streamer length of 26,247 ft (8,000 m), 53 fold, 32.8 ft

(10 m +1.5m) sound source depth, and 41.01 ft (12.5 m) by 131 ft (40 m) bin spacing. The 3DX data

processing was performed by WesternGeco using Kirchhoff pre-stack time migration. The processed

volume has a bin size of 41.01 ft (12.5 m) by 65.6 ft (20 m) and a sample rate of 4 milliseconds (Chart 1).

The data exhibit no trace or sample decimation of the final processed volume. Inlines are oriented

east-west, have a numerical increment of one, and are spaced at intervals of 41.01 ft (12.5 m). Crosslines

are oriented north-south, have a numerical increment of 1, and are spaced at intervals of 65.6 ft (20 m).

The seismic data set follows North American polarity convention and demonstrates a balanced, zero-phase

wavelet based on analysis of the seafloor reflector, top of salt reflector, and low-impedance, high-amplitude

anomalies indicative of gas sands.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT 

MISSISSIPPI CANYON AREA, GULF OF MEXICO 

FGCI Report No. 27.2012-2526-4 2

3-D Seismic Frequency. Based on power spectra analysis of the 3DX seismic data at 50% 

power, the frequency bandwidth for the E-Manatee data between the seafloor to about 1.0 s is 

approximately 15-64 Hz. This frequency bandwidth corresponds to a limit of separability of 29 ft, assuming 

a dominant frequency of 45 Hz and an average velocity of 5,400 ft/s in the shallow section. Other details 

regarding the data descriptions and limitations are found in Fugro Report No. 27.2012-2526. 

High-Resolution Geophysical Data. A high-resolution geophysical survey was provided by Noble

for interpretation in this study. The survey was acquired by C&C in September 2012 utilizing an 

autonomous underwater vehicle (AUV) system. The survey grid consists of 49 primary north-south

trending tracklines spaced 200 m apart and 14 east-west trending tielines spaced 900 m apart. 

Navigational fixes (shot points) were recorded at 410 ft (125 m) intervals. Multibeam (MBES), side-scan 

sonar (SSS), and sub-bottom profiler (SBP) were acquired during this survey. For further details 

concerning the survey, please refer to C&C Project No. 120578 delivered to Noble Energy in October of 

2012.

Depth Conversions. Water column time-to-depth conversions for the 3DX seismic volume are

based on a velocity of about 1,480 ft/s. Water depths along AUV tracklines are based on a velocity model 

generated from real-time velocimeter data. Comparison of the AUV water depths, and the water depths of

the seismic volume showed the seismic was generally ~15 ft deeper. Sub-seafloor depths for the 3DX 

seismic data are based on an interval velocity volume provided by Noble, and sub-bottom profiler depths 

are based on a velocity of 5,250 ft/s.

.Offset Well Data. Noble provided well log data, daily drilling reports, scout tickets, and 

paleontological data for offset wells MC 738-1 (Caterpillar Deep) and MC 739-1 (Hilbert). Well logs from 

MC 738-1 (Caterpillar Deep), located about 3.4 mi southeast of the proposed wellbore and MC 739-1 

(Hilbert), located about 4.1 mi east-northeast of the proposed wellbore, were utilized to calibrate sediment 

interpretations from seismic data.

Graphics. A Water Depth and Seafloor Features page-size figure (1:12,000-scale) showing the 

proposed wellsite, water depth contours and seafloor features, accompanies this wellsite assessment. 

A 2,000 ft radius circle around the proposed wellsite is shown as per BOEM NTL No. 2009-G40. 

A Composite Side-Scan Sonar Mosaic and a Multibeam Backscatter chart (1:12,000-scale) showing the 

seafloor conditions in the vicinity of the wellsite are included. Shallow geologic conditions at the proposed 

wellsite are summarized on the attached Tophole Prognosis Chart. The nearest 3DX inline, 3DX crossline, 

and AUV SBP profiles are attached to illustrate shallow geologic conditions in the vicinity of the proposed 

location. A page-size 1:12,000-scale Sub-Seafloor Geologic Features Chart is also included to illustrate 

geologic conditions in the vicinity of the proposed wellbore. The 3DX Seismic Power Spectrum is included 

as an assessment of the frequency content of the 3DX seismic data at the proposed wellbore. 

Proposed Well Location. The surface location for proposed Wellsite MC 738-A is located in 

northern MC Block 738 as follows:

Proposed Wellsite MC 738-A

Block 738, Mississippi Canyon Area

UTM Zone 16, NAD 1927

X = 1,224,346 ft Y = 10,250,202 ft

Latitude: 28° 14' 23"N Longitude: 88° 17' 33"W

Nearest E-Manatee Inline 14165 Nearest E-Manatee Crossline 3725

4,666 ft FWL 1,722 ft FSL
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-4 3

Water Depth and Seafloor Gradient. The MBES water depth at the proposed wellsite is

predicted to be about 6572 ft with zero datum at sea surface. The local gradient is less than 1° to the

north-northwest.

Seafloor Features. At the proposed MC 738-A wellsite, the local seafloor is smooth, featureless,

and appears stable. One northwest-southeast trending seafloor fault is identified in the vicinity of the

proposed wellsite. The seafloor fault scarp lies about 930 ft to the northeast, exhibits a seafloor relief of

about 40 ft and is associated with seafloor gradient of less than 10°. This fault is identified on SBP records

and 3DX seismic data and the fault plane will not be penetrated by the proposed wellbore. The seafloor

fault scarp meets the 75 m (245 ft) standoff distance as outlined by the BOEM in NTL No. 2008-G05.

Potential High-density Benthic Communities. Two areas of high seafloor multibeam

backscatter intensity indicative of possible hardground are located about 2,350 ft northwest and 3,500 ft

southwest of the proposed MC 738-A wellsite. There is no geophysical evidence of hydrocarbon seepage

sites or areas that could potentially support high-density benthic communities within 2,000 ft of the

proposed location. Therefore, there is a negligible potential for high-density communities of benthic and/or

chemosynthetic organisms within 2,000 ft of the proposed wellsite, in accordance with BOEM NTL

2009-G40.

Man-Made Obstructions. A search of Fugro’s GIS database conducted in February 2013 and a

review of the SSS data from the high-resolution geophysical data set indicated closest man-made feature is

one existing pipeline (Enterprise 20-24” SEG#15153) 1,700 ft south of the proposed wellsite.

The closest sonar targets (contacts # 21, # 24, and # 33) were detected about 2,400 ft northwest,

2,250 ft north, and 1,800 ft northeast of the proposed wellsite, respectively. These targets, and all the other

targets farther from the proposed wellsite, are interpreted as unidentified debris as outlined in the

archaeological assessment by C&C (Project No. 120578). Although no man-made features or other

potentially hazardous seafloor conditions are identified in the SSS data, we recommend that an ROV be

used to inspect the seafloor at the proposed wellsite immediately before spud-in to confirm that no seafloor

obstructions have appeared since the SSS survey was acquired.

Stratigraphy. The seafloor and five subsurface horizons (10, 20, 30, 40 and 60) were mapped to

divide the tophole section into five stratigraphic sequences (Sequence 1 through 5) of distinct seismic and

inferred lithologic character at the proposed wellbore. Predicted depths and thicknesses associated with

each of the mapped horizons and sequences are displayed on the attached Tophole Prognosis Chart for

the proposed wellsite MC 738-A drilling location.

At the proposed wellbore, Sequence 1 is 274 ft thick and is divided into an upper 160 ft thick

interval of parallel-stratified marine clays and thin, fine-grained MTDs and a lower 114 ft thick interval of

sand-prone sediments. Sequence 2 is 220 ft thick and is comprised of mostly fine-grained sediments

interbedded with thin, fine-grained MTDs and possible thin sands. The upper 25 ft of Sequence 2 consists

of possible sand-prone channel and overbank deposits which are interpreted to be part of the Blue Unit

(Ostermeier et al., 2000 and Winker et al., 2000).

Sequence 3 is cumulatively about 1,630 ft thick and is interpreted to represent the informally

described Green Unit. The upper 255 ft of Sequence 3 consist of fine-grained MTDs interbedded with

possible sand-prone sediments. The middle 550 ft of Sequence 3 are comprised of slope failure deposits

consisting of fine-grained MTDs interbedded with sand-prone channel and overbank deposits. The lower

825 ft of Sequence 3 are composed of slope failure deposits consisting of sand-prone channel and

overbank deposits interbedded with fine-grained MTDs. Sequence 4 is a 75 ft thick interval of possible

sand-prone sediments underlain by Sequence 5, which is composed of 1,465 ft of faulted, sand-prone

channel and overbank deposits interbedded with thin, fine-grained MTDs.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-4 4

Fault Penetrations. One buried fault plane will intersect the proposed wellbore at about 3,579 ft

BML. This fault is presumed to be inactive and is not expected to present a constraint to drilling operations.

However the sedimentary section within Sequence 5 is expected to be extensively fractured, and could

create secondary porosity and permeability that could cause drilling fluid loss to formation.

Gas Hydrate and Gas Hazards. Temperature and pressure conditions are favorable for the

presence of gas hydrates within the study area. The base of gas hydrate stability was modeled using the

fundamental gas hydrate phase equilibrium curve, which requires input for temperature, pressure, gas

mixture, and salinity (Sloan, 1990), and is estimated to be located within Sequence 3. Localized and

disseminated gas hydrates, if present, may occur above the base of has hydrate stability. Massive gas

hydrate accumulations at the proposed wellbore are not expected.

No high-amplitude anomalies interpreted to represent shallow gas will be penetrated in the tophole

section by a vertical wellbore at the proposed wellsite. Interpreted anomalies representing possible shallow

gas hazards in the tophole section within 3,000 ft of the proposed wellbore are located in Sequences 2

through 5. The closest amplitude anomalies to the proposed MC 738-A wellbore are located 706 ft to the

southwest within upper Sequence 2 and 825 ft to the northeast within Sequence 3. Because of the

sand-prone nature of lower Sequence 1 and upper Sequence 2, a low potential for shallow gas is assessed

for the intervals of these Sequences between 160 ft and 299 ft BML. Because of the presence of possible

sand-prone sediments within Sequences 3 through 5; a low potential for shallow gas is assessed for these

Sequences between 494 ft and the base of the tophole section at 3,664 ft BML. Possible gas sands in the

other stratigraphic units are located safely away from the borehole and should not pose any hazard or

constraint to drilling. Therefore, the remainder of the tophole section is assessed a negligible potential for

encountering significant gas accumulations.

Shallow-Water-Flow (SWF). A map presented by Pelletier and others (1999) shows the relative

magnitude of shallow-water-flow (SWF) hazards in the Northern Gulf of Mexico. On this map, the study

area falls within the moderate-risk zone. There are other reported cases of SWF in the general vicinity of

the study area. The MMS Internet Database indicates that SWF has occurred in the following wells in the

area: MC 696 (Blind Faith; very low severity event), MC 730-1 (moderate flow at 1,842 ft BML), MC 731-1

(low flow at 1,622 ft BML), MC 778-13 (low flow at 2,374 ft BML), MC 864-1 (moderate flow at 1,593 ft

BML). Based on these documented SWF events and the geologic conditions present within the study area,

we assess that the tophole section in MC 738 has the potential to be overpressured and that sand-prone

intervals, if penetrated, could cause a SWF event if not contained or otherwise mitigated.

Sequence 1 is comprised of mostly fine-grained sediments and is assessed a negligible SWF

potential. A lo w potential for SWF is assessed for the sand-prone intervals within lower Sequence 1,

lower Sequence 2, and Sequence 5. Sand-prone channel deposits within upper Sequence 2, between

274 ft and 299 ft BML, are interpreted to be part of the Blue Unit sands (Ostermeier et al., 2000 and Winker

et al., 2000) and are believed responsible for documented SWF occurrences at some wells in the area.

Therefore, upper Sequence 2 is assessed a moderate potential for SWF. Sequence 3 is sand-prone and is

interpreted to be part of the informally defined Green Unit sands inferred to have caused SWF events at

other wells in the area; therefore, all of Sequence 3 between 494 ft and 2,124 ft BML is assessed a

moderate potential for SWF at the proposed wellbore. Sequence 4 is interpreted to be sand-prone and is

overlain by fine-grained MTDs within Sequence 3; therefore, Sequence 4 is assessed a moderate potential

for SWF between about 2,124 ft and 2,199 ft BML.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-4 5

We appreciate the opportunity to work with you on this project and look forward to continuing as

your geohazards consultants. If you have any questions concerning this assessment, please do not

hesitate to call us (713-369-5600).

Sincerely,

FUGRO GEOCONSULTING, INC.

Jennifer Katrib

Senior Geoscientist

Hunter Danque Bruce Samuel

Project Geoscientist Geoscience Group Manager

Attachments:

1. Water Depth and Seafloor Features, Dantzler Prospect, Block 738, Gulf of Mexico, Proposed

Wellsite MC 738-A (1:12,000)

2. Side-Scan Sonar Mosaic, Dantzler Prospect, Block 738, Mississippi Canyon Area, Proposed

Wellsite MC 738-A (1:12,000)

3. Multibeam Backscatter Rendering, Dantzler Prospect, Block 738, Mississippi Canyon, Proposed

Wellsite MC 738-A

4. Sub-seafloor Geologic Features, Dantzler Prospect, Block 738, Mississippi Canyon Area, Proposed

Wellsite MC 738-A (1:12,000)

5. Tophole Prognosis Chart, Proposed Wellsite MC 738-A, Dantzler Prospect, Block 738, Mississippi

Canyon Area, Gulf of Mexico

6. E-MANATEE 3DX Seismic Profile, Inline 14165, Proposed Wellsite MC 738-A, Dantzler Prospect,

Block 738, Mississippi Canyon Area, Gulf of Mexico

7. E-MANATEE 3DX Seismic Profile, Crossline 3725, Proposed Wellsite MC 738-A, Dantzler

Prospect, Block 738, Mississippi Canyon Area, Gulf of Mexico

8. Sub-bottom Profile, Line 132, Proposed Wellsite MC 738-A, Dantzler Prospect, Block 738,

Mississippi Canyon Area, Gulf of Mexico

9. 3DX Seismic Power Spectrum, Proposed Wellsite MC 738-A, Dantzler Prospect, Block 738,

Mississippi Canyon Area, Gulf of Mexico
FUGRO GEOCONSULTING, INC.

Letter Report No. 27. 2012-2526-5

8 March 2013

Noble Energy, Inc.

100 Glenborough

Houston, Texas 77069

Attention: Mr. Bill Hobbs

Wellsite Clearance Letter

Proposed Wellsite MC 738-B

Block 738, Mississippi Canyon Area

OCS-G-33755

Introduction. Fugro GeoConsulting, Inc. (FGCI) was contracted by Noble Energy Inc. (Noble) to

prepare a wellsite clearance letter addressing shallow hazards for proposed Wellsite MC 738-B in

Block 738, Mississippi Canyon Area (OCS-G-33755). The proposed well is planned to be vertical through

the tophole section and will be drilled by a dynamically positioned rig. This letter is intended to address

specific seafloor and shallow geologic conditions within 3,000 ft of the proposed wellsite to the top of salt

reflector (about 3,665 ft BML). Shallow geologic conditions at the proposed wellbore are summarized on

the attached Tophole Prognosis Chart. Annotated data examples of the nearest 3D exploration seismic

survey lines, a sub-bottom profiler line, and four 1:12,000-scale charts showing the proposed wellsite are

included. The 1:12,000-scale illustrations include a water depth and seafloor features chart, a side-scan

sonar mosaic, a multibeam backscatter chart, and a sub-seafloor geologic features chart. A 2,000 ft radius

circle around the proposed wellsite is shown, as per Bureau of Ocean Energy Management (BOEM) Notice

to Lessees (NTL) 2009-G40. Please refer to Fugro Report No. 27.2012-2526, “Shallow Geohazards

Assessment, Dantzler Prospect, Blocks 738 and 782, Mississippi Canyon Area, Gulf of Mexico,” for a

comprehensive assessment of shallow geohazards within Blocks 738 and 782, and a complete list of

references used in this investigation. Please refer to C&C Technologies, Inc. Project No. 120578,

“Archaeological Assessment Report, Blocks 737, 738, 782 Mississippi Canyon Area, Gulf of Mexico,” for a

description of the AUV geophysical data used in this report, as well as a comprehensive archaeological

assessment.

3-D Seismic Survey Parameters. A pre-stack, time-migrated 3DX seismic data volume was used

for this assessment. The 3DX survey is a subset of the WesternGeco “E-Manatee” reprocessing effort

completed in August 2007 and is based in part on the “Mississippi Canyon Phase 11 (Ultra)” survey

acquired in 1997 in a north-south orientation with a streamer length of 26,247 ft (8,000 m), 53 fold, 32.8 ft

(10 m +1.5m) sound source depth, and 41.01 ft (12.5 m) by 131 ft (40 m) bin spacing. The 3DX data

processing was performed by WesternGeco using Kirchhoff pre-stack time migration. The processed

volume has a bin size of 41.01 ft (12.5 m) by 65.6 ft (20 m) and a sample rate of 4 milliseconds. The data

exhibit no trace or sample decimation of the final processed volume. Inlines are oriented east-west, have a

numerical increment of one, and are spaced at intervals of 41.01 ft (12.5 m). Crosslines are oriented northsouth, have a numerical increment of 1, and are spaced at intervals of 65.6 ft (20 m). The seismic data set

follows North American polarity convention and demonstrates a balanced, zero-phase wavelet based on

analysis of the seafloor reflector, top of salt reflector, and low-impedance, high-amplitude anomalies

indicative of gas sands.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-5 2

3-D Seismic Frequency. Based on power spectra analysis of the 3DX seismic data at 50%

power, the frequency bandwidth for the E-Manatee data between the seafloor to about 1.0 s is

approximately 15-64 Hz. This frequency bandwidth corresponds to a limit of separability of 29 ft, assuming

a dominant frequency of 45 Hz and an average velocity of 5,400 ft/s in the shallow section. Other details

regarding the data descriptions and limitations are found in Fugro Report No. 27.2012-2526.

High-Resolution Geophysical Data. A high-resolution geophysical survey was provided by Noble

for interpretation in this study. The survey was acquired by C&C in September 2012 utilizing an

autonomous underwater vehicle (AUV) system. The survey grid consists of 49 primary north-south

trending tracklines spaced 200 m apart and 14 east-west trending tielines spaced 900 m apart.

Navigational fixes (shot points) were recorded at 410 ft (125 m) intervals. Multibeam (MBES), side-scan

sonar (SSS), and sub-bottom profiler (SBP) were acquired during this survey. For further details

concerning the survey, please refer to C&C Project No. 120578 delivered to Noble Energy in October of

2012.

Depth Conversions. Water column time-to-depth conversions for the 3DX seismic volume are

based on a velocity of about 1,480 m/s. Water depths along AUV tracklines are based on a velocity model

generated from real-time velocimeter data. Comparison of the AUV water depths, and the water depths of

the seismic volume showed the seismic was generally ~15 ft deeper. Sub-seafloor depths for the 3DX

seismic data are based on an interval velocity volume provided by Noble, and sub-bottom profiler depths

are based on a velocity of 5,250 ft/s.

.Offset Well Data. Noble provided well log data, daily drilling reports, scout tickets, and

paleontological data for offset wells MC 738-1 (Caterpillar Deep) and MC 739-1 (Hilbert). Well logs from

MC 738-1 (Caterpillar Deep), located about 3.4 mi southeast of the proposed wellbore and MC 739-1

(Hilbert), located about 4.1 mi east-northeast of the proposed wellbore, were utilized to calibrate sediment

interpretations from seismic data.

Graphics. A Water Depth and Seafloor Features page-size figure (1:12,000-scale) showing the

proposed wellsite, water depth contours and seafloor features, accompanies this wellsite assessment.

A 2,000 ft radius circle around the proposed wellsite is shown as per BOEM NTL No. 2009-G40.

Side-Scan Sonar Mosaic and Multibeam Backscatter charts (1:12,000-scale) showing the seafloor

conditions in the vicinity of the wellsite are included. Shallow geologic conditions at the proposed wellsite

are summarized on the attached Tophole Prognosis Chart. The nearest 3DX inline, 3DX crossline, and

AUV SBP profiles are attached to illustrate shallow geologic conditions in the vicinity of the proposed

location. A page-size 1:12,000-scale Sub-Seafloor Geologic Features Chart is also included to illustrate

geologic conditions in the vicinity of the proposed wellbore. The 3DX Seismic Power Spectrum is included

as an assessment of the frequency content of the 3DX seismic data at the proposed wellbore.

Proposed Well Location. The surface location for proposed Wellsite MC 738-B is located in

northern MC Block 738 as follows:

Proposed Wellsite MC 738-B

Block 738, Mississippi Canyon Area

UTM Zone 16, NAD 1927

X = 1,224,427 ft Y = 10,250,134 ft

Latitude: 28° 14' 22"N Longitude: 88° 17' 32"W

Nearest E-Manatee Inline 14164 Nearest E-Manatee Crossline 3727

4,747 ft FWL 1,654 ft FSL
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-5 3

Water Depth and Seafloor Gradient. The MBES water depth at the proposed wellsite is

predicted to be about 6571 ft with zero datum at sea surface. The local gradient is less than 1° to the

north-northwest.

Seafloor Features. At the proposed MC 738-B wellsite, the local seafloor is smooth, featureless,

and appears stable. One northwest-southeast trending seafloor fault is identified in the vicinity of the

proposed wellsite. The seafloor fault scarp lies about 920 ft to the northeast, exhibits a seafloor relief of

about 40 ft and is associated with seafloor gradient of less than 10°. This fault is identified on SBP records

and 3DX seismic data and the fault plane will not be penetrated by the proposed wellbore. The seafloor

fault scarp meets the 75 m (245 ft) standoff distance as outlined by the BOEM in NTL No. 2008-G05.

Potential High-density Benthic Communities. Two areas of high seafloor multibeam

backscatter intensity indicative of possible hardground are located about 2,300 ft northwest and 3,440 ft

southwest of the proposed MC 738-B wellsite. There is no geophysical evidence of hydrocarbon seepage

sites or areas that could potentially support high-density benthic communities within 2,000 ft of the

proposed location. Therefore, there is a negligible potential for high-density communities of benthic and/or

chemosynthetic organisms within 2,000 ft of the proposed wellsite, in accordance with BOEM NTL

2009-G40.

Man-Made Obstructions. A search of Fugro’s GIS database conducted in March 2013 and a

review of the SSS data from the high-resolution geophysical data set indicated closest man-made feature is

one existing pipeline (Enterprise 20-24” SEG#15153) 1,625 ft south of the proposed wellsite.

The closest sonar targets (contacts # 21, # 24, and # 33) were detected about 2,420 ft northwest,

2,280 ft north, and 1,830 ft northeast of the proposed wellsite, respectively. These targets, and all the other

targets farther from the proposed wellsite, are interpreted as unidentified debris as outlined in the

archaeological assessment by C&C (Project No. 120578). Although no man-made features or other

potentially hazardous seafloor conditions are identified in the SSS data, we recommend that an ROV be

used to inspect the seafloor at the proposed wellsite immediately before spud-in to confirm that no seafloor

obstructions have appeared since the SSS survey was acquired.

Stratigraphy. The seafloor and five subsurface horizons (10, 20, 30, 40 and 60) were mapped to

divide the tophole section into five stratigraphic sequences (Sequence 1 through 5) of distinct seismic and

inferred lithologic character at the proposed wellbore. Predicted depths and thicknesses associated with

each of the mapped horizons and sequences are displayed on the attached Tophole Prognosis Chart for

the proposed wellsite MC 738-B drilling location.

At the proposed wellbore, Sequence 1 is 271 ft thick and is divided into an upper 161 ft thick

interval of parallel-stratified marine clays and thin, fine-grained MTDs and a lower 110 ft thick interval of

sand-prone sediments. Sequence 2 is 219 ft thick and is comprised of mostly fine-grained sediments

interbedded with thin, fine-grained MTDs and possible thin sands. The upper 29 ft of Sequence 2 consists

of possible sand-prone channel and overbank deposits which are interpreted to be part of the Blue Unit

(Ostermeier et al., 2000 and Winker et al., 2000).

Sequence 3 is cumulatively about 1,635 ft thick and is interpreted to represent the informally

described Green Unit. The upper 260 ft of Sequence 3 consist of fine-grained MTDs interbedded with

possible sand-prone sediments. The middle 550 ft of Sequence 3 are comprised of slope failure deposits

consisting of fine-grained MTDs interbedded with sand-prone channel and overbank deposits. The lower

825 ft of Sequence 3 are composed of slope failure deposits consisting of sand-prone channel and

overbank deposits interbedded with fine-grained MTDs. Sequence 4 is a 70 ft thick interval of possible

sand-prone sediments underlain by Sequence 5, which is composed of 1,470 ft of faulted, sand-prone

channel and overbank deposits interbedded with thin, fine-grained MTDs.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-5 4

Fault Penetrations. One buried fault plane will intersect the proposed wellbore at about 3,421 ft

BML. This fault is presumed to be inactive and is not expected to present a constraint to drilling operations.

However the sedimentary section within Sequence 5 is expected to be extensively fractured, and could

create secondary porosity and permeability that could cause drilling fluid loss to formation.

Gas Hydrate and Gas Hazards. Temperature and pressure conditions are favorable for the

presence of gas hydrates within the study area. The base of gas hydrate stability was modeled using the

fundamental gas hydrate phase equilibrium curve, which requires input for temperature, pressure, gas

mixture, and salinity (Sloan, 1990), and is estimated to be located within Sequence 3. Localized and

disseminated gas hydrates, if present, may occur above the base of has hydrate stability. Massive gas

hydrate accumulations at the proposed wellbore are not expected.

No high-amplitude anomalies interpreted to represent shallow gas will be penetrated in the tophole

section by a vertical wellbore at the proposed wellsite. Interpreted anomalies representing possible shallow

gas hazards in the tophole section within 3,000 ft of the proposed wellbore are located in Sequences 2

through 5. The closest amplitude anomalies to the proposed MC 738-B wellbore are located 830 ft to the

northeast, 695 ft to the southwest, and 1,610 ft to the southwest within upper Sequence 2 and Sequence 3.

Because of the sand-prone nature of lower Sequence 1 and upper Sequence 2, a low potential for shallow

gas is assessed for the intervals of these Sequences between 161 ft and 300 ft BML. Because of the

presence of possible sand-prone sediments within Sequences 3 through 5; a low potential for shallow gas

is assessed for these Sequences between 490 ft and the base of the tophole section at 3,665 ft BML.

Possible gas sands in the other stratigraphic units are located safely away from the borehole and should

not pose any hazard or constraint to drilling. Therefore, the remainder of the tophole section is assessed a

negligible potential for encountering significant gas accumulations.

Shallow-Water-Flow (SWF). A map presented by Pelletier and others (1999) shows the relative

magnitude of shallow-water-flow (SWF) hazards in the Northern Gulf of Mexico. On this map, the study

area falls within the moderate-risk zone. There are other reported cases of SWF in the general vicinity of

the study area. The BOEM Internet Database indicates that SWF has occurred in the following wells in the

area: MC 696 (Blind Faith; very low severity event), MC 730-1 (moderate flow at 1,842 ft BML), MC 731-1

(low flow at 1,622 ft BML), MC 778-13 (low flow at 2,374 ft BML), MC 864-1 (moderate flow at 1,593 ft

BML). Based on these documented SWF events and the geologic conditions present within the study area,

we assess that the tophole section in MC 738 has the potential to be overpressured and that sand-prone

intervals, if penetrated, could cause a SWF event if not contained or otherwise mitigated.

Upper Sequence 1 is comprised of mostly fine-grained sediments and is assessed a negligible

SWF potential. A lo w potential for SWF is assessed for the sand-prone intervals within lower

Sequence 1, lower Sequence 2, and Sequence 5. Sand-prone channel deposits within upper Sequence 2,

between 271 ft and 300 ft BML, are interpreted to be part of the Blue Unit sands (Ostermeier et al., 2000

and Winker et al., 2000) and are believed responsible for documented SWF occurrences at some wells in

the area. Therefore, upper Sequence 2 is assessed a moderate potential for SWF. Sequence 3 is

sand-prone and is interpreted to be part of the informally defined Green Unit sands inferred to have caused

SWF events at other wells in the area; therefore, all of Sequence 3 between 490 ft and 2,125 ft BML is

assessed a moderate potential for SWF at the proposed wellbore. Sequence 4 is interpreted to be sandprone and is overlain by fine-grained MTDs within Sequence 3; therefore, Sequence 4 is assessed a

moderate potential for SWF between about 2,125 ft and 2,195 ft BML.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-5 5

We appreciate the opportunity to work with you on this project and look forward to continuing as

your geohazards consultants. If you have any questions concerning this assessment, please do not

hesitate to call us (713-369-5600).

Sincerely,

FUGRO GEOCONSULTING, INC.

Jennifer Katrib

Senior Geoscientist

Hunter Danque Bruce Samuel

Project Geoscientist Geoscience Group Manager

Attachments:

1. Water Depth and Seafloor Features, Dantzler Prospect, Block 738, Gulf of Mexico, Proposed

Wellsite MC 738-B (1:12,000)

2. Side-Scan Sonar Mosaic, Dantzler Prospect, Block 738, Mississippi Canyon Area, Proposed

Wellsite MC 738-B (1:12,000)

3. Multibeam Backscatter Rendering, Dantzler Prospect, Block 738, Mississippi Canyon, Proposed

Wellsite MC 738-B

4. Sub-seafloor Geologic Features, Dantzler Prospect, Block 738, Mississippi Canyon Area, Proposed

Wellsite MC 738-B (1:12,000)

5. Tophole Prognosis Chart, Proposed Wellsite MC 738-B, Dantzler Prospect, Block 738, Mississippi

Canyon Area, Gulf of Mexico

6. 3DX Seismic Profile, Inline 14164, Proposed Wellsite MC 738-B, Dantzler Prospect, Block 738,

Mississippi Canyon Area, Gulf of Mexico

7. 3DX Seismic Profile, Crossline 3727, Proposed Wellsite MC 738-B, Dantzler Prospect, Block 738,

Mississippi Canyon Area, Gulf of Mexico

8. Sub-bottom Profile, Line 132, Proposed Wellsite MC 738-B, Dantzler Prospect, Block 738,

Mississippi Canyon Area, Gulf of Mexico

9. 3DX Seismic Power Spectrum, Proposed Wellsite MC 738-B, Dantzler Prospect, Block 738,

Mississippi Canyon Area, Gulf of Mexico
FUGRO GEOCONSULTING, INC.

Letter Report No. 27. 2012-2526-1

13 February 2013

Noble Energy, Inc.

100 Glenborough

Houston, Texas 77069

Attention: Mr. Bill Hobbs

Wellsite Clearance Letter

Proposed Wellsite MC 782-A

Block 782, Mississippi Canyon Area

OCS-G-33757

Introduction. Fugro GeoConsulting, Inc. (FGCI) was contracted by Noble Energy Inc. (Noble) to

prepare a wellsite clearance letter addressing shallow hazards for proposed Wellsite MC 782-A in

Block 782, Mississippi Canyon Area (OCS-G-33757). The proposed well is planned to be vertical through

the tophole section and will be drilled by a dynamically positioned rig. This letter is intended to address

specific seafloor and shallow geologic conditions within 3,000 ft of the proposed wellsite to the top of salt

reflector (about 3,260 ft BML). Shallow geologic conditions at the proposed wellbore are summarized on

the attached Tophole Prognosis Chart. Annotated data examples of the nearest 3D exploration seismic

survey lines, a sub-bottom profiler line, and four 1:12,000-scale charts showing the proposed wellsite are

included. The 1:12,000-scale illustrations include a water depth and seafloor features chart, a side-scan

sonar mosaic, a multibeam backscatter chart, and a sub-seafloor geologic features chart. A 2,000 ft radius

circle around the proposed wellsite is shown, as per Bureau of Ocean Energy Management (BOEM) Notice

to Lessees (NTL) 2009-G40. Please refer to Fugro Report No. 27.2012-2526, “Shallow Geohazards

Assessment, Dantzler Prospect, Blocks 738 and 782, Mississippi Canyon Area, Gulf of Mexico,” for a

comprehensive assessment of shallow geohazards within Blocks 738 and 782, and a complete list of

references used in this investigation. Please refer to C&C Technologies, Inc. Project No. 120578,

“Archaeological Assessment Report, Blocks 737, 738, 782 Mississippi Canyon Area, Gulf of Mexico,” for a

description of the AUV geophysical data used in this report, as well as a comprehensive archaeological

assessment.

3-D Seismic Survey Parameters. A pre-stack, time-migrated 3DX seismic data volume was used

for this assessment. The 3DX survey is a subset of the WesternGeco “E-Manatee” reprocessing effort

completed in August 2007 and is based in part on the “Mississippi Canyon Phase 11 (Ultra)” survey

acquired in 1997 in a north-south orientation with a streamer length of 26,247 ft (8,000 m), 53 fold, 32.8 ft

(10 m +1.5m) sound source depth, and 41.01 ft (12.5 m) by 131 ft (40 m) bin spacing. The 3DX data

processing was performed by WesternGeco using Kirchhoff pre-stack time migration. The processed

volume has a bin size of 41.01 ft (12.5 m) by 65.6 ft (20 m) and a sample rate of 4 milliseconds (Chart 1).

The data exhibit no trace or sample decimation of the final processed volume. Inlines are oriented

east-west, have a numerical increment of one, and are spaced at intervals of 41.01 ft (12.5 m). Crosslines

are oriented north-south, have a numerical increment of 1, and are spaced at intervals of 65.6 ft (20 m).

The seismic data set follows North American polarity convention and demonstrates a balanced, zero-phase

wavelet based on analysis of the seafloor reflector, top of salt reflector, and low-impedance, high-amplitude

anomalies indicative of gas sands.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-1 2

3-D Seismic Frequency. Based on power spectra analysis of the 3DX seismic data at 50%

power, the frequency bandwidth for the E-Manatee data between the seafloor to about 1.0 s is

approximately 15-64 Hz. This frequency bandwidth corresponds to a limit of separability of 29 ft, assuming

a dominant frequency of 45 Hz and an average velocity of 5,400 ft/s in the shallow section. Other details

regarding the data descriptions and limitations are found in Fugro Report No. 27.2012-2526.

High-Resolution Geophysical Data. A high-resolution geophysical survey was provided by Noble

for interpretation in this study. The survey was acquired by C&C in September 2012 utilizing an

autonomous underwater vehicle (AUV) system. The survey grid consists of 49 primary north-south

trending tracklines spaced 200 m apart and 14 east-west trending tielines spaced 900 m apart.

Navigational fixes (shot points) were recorded at 410 ft (125 m) intervals. Multibeam (MBES), side-scan

sonar (SSS), and sub-bottom profiler (SBP) were acquired during this survey. For further details

concerning the survey, please refer to C&C Project No. 120578 delivered to Noble Energy in October of

2012.

Depth Conversions. Water column time-to-depth conversions for the 3DX seismic volume are

based on a velocity of about 1,480 ft/s. Water depths along AUV tracklines are based on a velocity model

generated from real-time velocimeter data. Comparison of the AUV water depths, and the water depths of

the seismic volume showed the seismic was generally ~15 ft deeper. Sub-seafloor depths for the 3DX

seismic data are based on an interval velocity volume provided by Noble, and sub-bottom profiler depths

are based on a velocity of 5,250 ft/s.

.Offset Well Data. Noble provided well log data, daily drilling reports, scout tickets, and

paleontological data for offset wells MC 782-1 (Caterpillar Deep) and MC 739-1 (Hilbert). Well logs from

MC 782-1 (Caterpillar Deep), located about 3 mi southeast of the proposed wellbore and MC 739-1

(Hilbert), located about 4.2 mi east-northeast of the proposed wellbore, were utilized to calibrate sediment

interpretations from seismic data.

Graphics. A Water Depth and Seafloor Features page-size figure (1:12,000-scale) showing the

proposed wellsite, water depth contours and seafloor features, accompanies this wellsite assessment.

A 2,000 ft radius circle around the proposed wellsite is shown as per BOEM NTL No. 2009-G40.

A Composite Side-Scan Sonar Mosaic and a Multibeam Backscatter chart (1:12,000-scale) showing the

seafloor conditions in the vicinity of the wellsite are included. Shallow geologic conditions at the proposed

wellsite are summarized on the attached Tophole Prognosis Chart. The nearest 3DX inline, 3DX crossline,

and AUV SBP profiles are attached to illustrate shallow geologic conditions in the vicinity of the proposed

location. A page-size 1:12,000-scale Sub-Seafloor Geologic Features Chart is also included to illustrate

geologic conditions in the vicinity of the proposed wellbore. The 3DX Seismic Power Spectrum is included

as an assessment of the frequency content of the 3DX seismic data at the proposed wellbore.

Proposed Well Location. The surface location for proposed Wellsite MC 782-A is located in

northern MC Block 782 as follows:

Proposed Wellsite MC 782-A

Block 782, Mississippi Canyon Area

UTM Zone 16, NAD 1927

X = 1,224,943 ft Y = 10,247,759 ft

Latitude: 28° 13' 59.053"N Longitude: 88° 17' 26.422"W

Nearest E-Manatee Inline 14128 Nearest E-Manatee Crossline 3740

5,263 ft FWL 721 ft FNL
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-1 3

Water Depth and Seafloor Gradient. The MBES water depth at the proposed wellsite is

predicted to be about 6576 ft with zero datum at sea surface. The local gradient is less than 1° to the east.

Seafloor Features. At the proposed MC 782-A wellsite, the local seafloor is smooth, featureless,

and appears stable. Several northwest-southeast trending seafloor faults are identified in the vicinity of the

proposed wellsite. The closest seafloor fault scarp lies about 2,070 ft to the southwest, exhibits a seafloor

relief of about 10 ft and is associated with seafloor gradient of less than 4°. Another seafloor fault is about

2,360 ft northeast of the proposed wellsite, and the seafloor scarp defined by this fault has maximum relief

of about 40 ft and a seafloor gradient of less than 10°. These faults are identified on SBP records and 3DX

seismic data. No seafloor faults will be penetrated by the proposed wellbore, and the seafloor fault scarps

meet the 75 m (245 ft) standoff distance as outlined by the BOEM in NTL No. 2008-G05.

Potential High-density Benthic Communities. Two areas of high seafloor multibeam

backscatter intensity indicative of possible hardground are located about 2,050 ft and 2,600 ft southwest of

the proposed MC 782-A wellsite. There is no geophysical evidence of hydrocarbon seepage sites or areas

that could potentially support high-density benthic communities within 2,000 ft of the proposed location.

Therefore, there is a negligible potential for high-density communities of benthic and/or chemosynthetic

organisms within 2,000 ft of the proposed wellsite, in accordance with BOEM NTL 2009-G40.

Man-Made Obstructions. A search of Fugro’s GIS database conducted in February 2013 and a

review of the SSS data from the high-resolution geophysical data set indicated closest man-made feature is

one existing pipeline (Enterprise 20-24” SEG#15153) 694 ft north of the proposed wellsite.

The closest sonar target (contact # 37) was detected about 2,200 ft southeast of the proposed

wellsite. This target, and all the other targets farther from the proposed wellsite, are interpreted as

unidentified debris as outlined in the archaeological assessment by C&C (Project No. 120578). Although

no man-made features or other potentially hazardous seafloor conditions are identified in the SSS data, we

recommend that an ROV be used to inspect the seafloor at the proposed wellsite immediately before

spud-in to confirm that no seafloor obstructions have appeared since the SSS survey was acquired.

Stratigraphy. The seafloor and five subsurface horizons (10, 20, 30, 40 and 60) were mapped to

divide the tophole section into five stratigraphic sequences (Sequence 1 through 5) of distinct seismic and

inferred lithologic character at the proposed wellbore. Predicted depths and thicknesses associated with

each of the mapped horizons and sequences are displayed on the attached Tophole Prognosis Chart for

the proposed wellsite MC 782-A drilling location.

At the proposed wellbore, Sequence 1 is 275 ft thick and is divided into an upper 165 ft thick

interval of parallel-stratified marine clays and thin, fine-grained MTDs and a lower 110 ft thick interval of

sand-prone sediments. Sequence 2 is 215 ft thick and is comprised of mostly fine-grained sediments

interbedded with thin, fine-grained MTDs and possible thin sands. The upper 25 ft of Sequence 2 consists

of possible sand-prone channel and overbank deposits which are interpreted to be part of the Blue Unit

(Ostermeier et al., 2000 and Winker et al., 2000).

Sequence 3 is cumulatively about 1,730 ft thick and is interpreted to represent the informally

described Green Unit. The upper 255 ft of Sequence 3 consist of fine-grained MTDs interbedded with

possible sand-prone deposits. The middle 675 ft of Sequence 3 are comprised of slope failure deposits

consisting of sand-prone channel and overbank deposits interbedded with fine-grained MTDs. The lower

800 ft of Sequence 3 consist of mostly fine-grained slope failure deposits with possible sand-prone

sediment blocks. Sequence 4 is a 465 ft thick interval of faulted, fine-grained sediments underlain by

Sequence 5, which is composed of 575 ft of faulted, sand-prone channel and overbank deposits

interbedded with thin, fine-grained MTDs.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-1 4

Fault Penetrations. One buried fault plane will intersect the proposed wellbore at about 3,035 ft

BML. This fault is presumed to be inactive and is not expected to present a constraint to drilling operations.

However the sedimentary section within Sequences 4 and 5 is expected to be extensively fractured, and

could create secondary porosity and permeability that could cause drilling fluid loss to formation.

Gas Hydrate and Gas Hazards. Temperature and pressure conditions are favorable for the

presence of gas hydrates within the study area. The base of gas hydrate stability was modeled using the

fundamental gas hydrate phase equilibrium curve, which requires input for temperature, pressure, gas

mixture, and salinity (Sloan, 1990), and is estimated to be located within Sequence 3. Localized and

disseminated gas hydrates, if present, may occur above the base of has hydrate stability. Massive gas

hydrate accumulations at the proposed wellbore are not expected.

No high-amplitude anomalies interpreted to represent shallow gas will be penetrated in the tophole

section by a vertical wellbore at the proposed wellsite. Interpreted anomalies representing possible shallow

gas hazards in the tophole section within 3,000 ft of the proposed wellbore are located in Sequences 2

through 5. The closest amplitude anomalies to the proposed MC 782-A wellbore are located 310 ft to the

south within upper Sequence 2 and 990 ft to the northwest within Sequence 3. Because of the sand-prone

nature of lower Sequence 1 and upper Sequence 2, a low potential for shallow gas is assessed for the

intervals of these Sequences between 165 ft and 300 ft BML. Because of the presence of possible

sand-prone sediments within Sequences 3 and 5; a low potential for shallow gas is assessed for these

Sequences between 490 ft and 2,220 ft BML and between 2,685 ft and 3,260 ft BML, respectively.

Possible gas sands in the other stratigraphic units are located safely away from the borehole and should

not pose any hazard or constraint to drilling. Therefore, the remainder of the tophole section is assessed a

negligible potential for encountering significant gas accumulations.

Shallow-Water-Flow (SWF). A map presented by Pelletier and others (1999) shows the relative

magnitude of shallow-water-flow (SWF) hazards in the Northern Gulf of Mexico. On this map, the study

area falls within the moderate-risk zone. There are other reported cases of SWF in the general vicinity of

the study area. The MMS Internet Database indicates that SWF has occurred in the following wells in the

area: MC 696 (Blind Faith; very low severity event), MC 730-1 (moderate flow at 1,842 ft BML), MC 731-1

(low flow at 1,622 ft BML), MC 778-13 (low flow at 2,374 ft BML), MC 864-1 (moderate flow at 1,593 ft

BML). Based on these documented SWF events and the geologic conditions present within the study area,

we assess that the tophole section in MC 782 has the potential to be overpressured and that sand-prone

intervals, if penetrated, could cause a SWF event if not contained or otherwise mitigated.

Sequences 1 and 4 are comprised of mostly fine-grained sediments and are assessed a negligible

SWF potential. A lo w potential for SWF is assessed for the sand-prone intervals within lower

Sequence 1, lower Sequence 2, and Sequence 5. Sand-prone channel deposits within upper Sequence 2,

between 275 ft and 300 ft BML, are interpreted to be part of the Blue Unit sands (Ostermeier et al., 2000

and Winker et al., 2000) and are believed responsible for documented SWF occurrences at some wells in

the area. Therefore, upper Sequence 2 is assessed a moderate potential for SWF. Sequence 3 is

sand-prone and is interpreted to be part of the informally defined Green Unit sands inferred to have caused

SWF events at other wells in the area; therefore, all of Sequence 3 between 490 ft and 2,220 ft BML is

assessed a moderate potential for SWF at the proposed wellbore.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-1 5

We appreciate the opportunity to work with you on this project and look forward to continuing as

your geohazards consultants. If you have any questions concerning this assessment, please do not

hesitate to call us (713-369-5600).

Sincerely,

FUGRO GEOCONSULTING, INC.

Jennifer Katrib

Senior Geoscientist

Hunter Danque Bruce Samuel

Project Geoscientist Geoscience Group Manager

Attachments:

1. Water Depth and Seafloor Features, Dantzler Prospect, Block 782, Gulf of Mexico, Proposed

Wellsite MC 782-A (1:12,000)

2. Side-Scan Sonar Mosaic, Dantzler Prospect, Block 782, Mississippi Canyon Area, Proposed

Wellsite MC 782-A (1:12,000)

3. Multibeam Backscatter Rendering, Dantzler Prospect, Block 782, Mississippi Canyon, Proposed

Wellsite MC 782-A

4. Sub-seafloor Geologic Features, Dantzler Prospect, Block 782, Mississippi Canyon Area, Proposed

Wellsite MC 782-A (1:12,000)

5. Tophole Prognosis Chart, Proposed Wellsite MC 782-A, Dantzler Prospect, Block 782, Mississippi

Canyon Area, Gulf of Mexico

6. E-MANATEE 3DX Seismic Profile, Inline 14128, Proposed Wellsite MC 782-A, Dantzler Prospect,

Block 782, Mississippi Canyon Area, Gulf of Mexico

7. E-MANATEE 3DX Seismic Profile, Crossline 3740, Proposed Wellsite MC 782-A, Dantzler

Prospect, Block 782, Mississippi Canyon Area, Gulf of Mexico

8. Sub-bottom Profile, Line 133-e-1, Proposed Wellsite MC 782-A, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico

9. 3DX Seismic Power Spectrum, Proposed Wellsite MC 782-A, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico
FUGRO GEOCONSULTING, INC.

Letter Report No. 27. 2012-2526-2

13 February 2013

Noble Energy, Inc.

100 Glenborough

Houston, Texas 77069

Attention: Mr. Bill Hobbs

Wellsite Clearance Letter

Proposed Wellsite MC 782-B

Block 782, Mississippi Canyon Area

OCS-G-33757

Introduction. Fugro GeoConsulting, Inc. (FGCI) was contracted by Noble Energy Inc. (Noble) to

prepare a wellsite clearance letter addressing shallow hazards for proposed Wellsite MC 782-B in

Block 782, Mississippi Canyon Area (OCS-G-33757). The proposed well is planned to be vertical through

the tophole section and will be drilled by a dynamically positioned rig. This letter is intended to address

specific seafloor and shallow geologic conditions within 3,000 ft of the proposed wellsite to the top of salt

reflector (about 3,426 ft BML). Shallow geologic conditions at the proposed wellbore are summarized on

the attached Tophole Prognosis Chart. Annotated data examples of the nearest 3D exploration seismic

survey lines, a sub-bottom profiler line, and four 1:12,000-scale charts showing the proposed wellsite are

included. The 1:12,000-scale illustrations include a water depth and seafloor features chart, a side-scan

sonar mosaic, a multibeam backscatter chart, and a sub-seafloor geologic features chart. A 2,000 ft radius

circle around the proposed wellsite is shown, as per Bureau of Ocean Energy Management (BOEM) Notice

to Lessees (NTL) 2009-G40. Please refer to Fugro Report No. 27.2012-2526, “Shallow Geohazards

Assessment, Dantzler Prospect, Blocks 738 and 782, Mississippi Canyon Area, Gulf of Mexico,” for a

comprehensive assessment of shallow geohazards within Blocks 738 and 782, and a complete list of

references used in this investigation. Please refer to C&C Technologies, Inc. Project No. 120578,

“Archaeological Assessment Report, Blocks 737, 738, 782 Mississippi Canyon Area, Gulf of Mexico,” for a

description of the AUV geophysical data used in this report, as well as a comprehensive archaeological

assessment.

3-D Seismic Survey Parameters. A pre-stack, time-migrated 3DX seismic data volume was used

for this assessment. The 3DX survey is a subset of the WesternGeco “E-Manatee” reprocessing effort

completed in August 2007 and is based in part on the “Mississippi Canyon Phase 11 (Ultra)” survey

acquired in 1997 in a north-south orientation with a streamer length of 26,247 ft (8,000 m), 53 fold, 32.8 ft

(10 m +1.5m) sound source depth, and 41.01 ft (12.5 m) by 131 ft (40 m) bin spacing. The 3DX data

processing was performed by WesternGeco using Kirchhoff pre-stack time migration. The processed

volume has a bin size of 41.01 ft (12.5 m) by 65.6 ft (20 m) and a sample rate of 4 milliseconds (Chart 1).

The data exhibit no trace or sample decimation of the final processed volume. Inlines are oriented

east-west, have a numerical increment of one, and are spaced at intervals of 41.01 ft (12.5 m). Crosslines

are oriented north-south, have a numerical increment of 1, and are spaced at intervals of 65.6 ft (20 m).

The seismic data set follows North American polarity convention and demonstrates a balanced, zero-phase

wavelet based on analysis of the seafloor reflector, top of salt reflector, and low-impedance, high-amplitude

anomalies indicative of gas sands.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-2 2

3-D Seismic Frequency. Based on power spectra analysis of the 3DX seismic data at 50%

power, the frequency bandwidth for the E-Manatee data between the seafloor to about 1.0 s is

approximately 15-64 Hz. This frequency bandwidth corresponds to a limit of separability of 29 ft, assuming

a dominant frequency of 45 Hz and an average velocity of 5,400 ft/s in the shallow section. Other details

regarding the data descriptions and limitations are found in Fugro Report No. 27.2012-2526.

High-Resolution Geophysical Data. A high-resolution geophysical survey was provided by Noble

for interpretation in this study. The survey was acquired by C&C in September 2012 utilizing an

autonomous underwater vehicle (AUV) system. The survey grid consists of 49 primary north-south

trending tracklines spaced 200 m apart and 14 east-west trending tielines spaced 900 m apart.

Navigational fixes (shot points) were recorded at 410 ft (125 m) intervals. Multibeam (MBES), side-scan

sonar (SSS), and sub-bottom profiler (SBP) were acquired during this survey. For further details

concerning the survey, please refer to C&C Project No. 120578 delivered to Noble Energy in October of

2012.

Depth Conversions. Water column time-to-depth conversions for the 3DX seismic volume are

based on a velocity of about 1,480 ft/s. Water depths along AUV tracklines are based on a velocity model

generated from real-time velocimeter data. Comparison of the AUV water depths, and the water depths of

the seismic volume showed the seismic was generally ~15 ft deeper. Sub-seafloor depths for the 3DX

seismic data are based on an interval velocity volume provided by Noble, and sub-bottom profiler depths

are based on a velocity of 5,250 ft/s.

.Offset Well Data. Noble provided well log data, daily drilling reports, scout tickets, and

paleontological data for offset wells MC 782-1 (Caterpillar Deep) and MC 739-1 (Hilbert). Well logs from

MC 782-1 (Caterpillar Deep), located about 2.5 mi southeast of the proposed wellbore and MC 739-1

(Hilbert), located about 4.2 mi northeast of the proposed wellbore, were utilized to calibrate sediment

interpretations from seismic data.

Graphics. A Water Depth and Seafloor Features page-size figure (1:12,000-scale) showing the

proposed wellsite, water depth contours and seafloor features, accompanies this wellsite assessment.

A 2,000 ft radius circle around the proposed wellsite is shown as per BOEM NTL No. 2009-G40.

A Composite Side-Scan Sonar Mosaic and a Multibeam Backscatter chart (1:12,000-scale) showing the

seafloor conditions in the vicinity of the wellsite are included. Shallow geologic conditions at the proposed

wellsite are summarized on the attached Tophole Prognosis Chart. The nearest 3DX inline, 3DX crossline,

and AUV SBP profiles are attached to illustrate shallow geologic conditions in the vicinity of the proposed

location. A page-size 1:12,000-scale Sub-Seafloor Geologic Features Chart is also included to illustrate

geologic conditions in the vicinity of the proposed wellbore. The 3DX Seismic Power Spectrum is included

as an assessment of the frequency content of the 3DX seismic data at the proposed wellbore.

Proposed Well Location. The surface location for proposed Wellsite MC 782-B is located in

northern MC Block 782 as follows:

Proposed Wellsite MC 782-B

Block 782, Mississippi Canyon Area

UTM Zone 16, NAD 1927

X = 1,226,029 ft Y = 10,245,555 ft

Latitude: 28° 13' 37"N Longitude: 88° 17' 14"W

Nearest E-Manatee Inline 14094 Nearest E-Manatee Crossline 3723

6,349 ft FWL 2,925 ft FNL
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-2 3

Water Depth and Seafloor Gradient. The MBES water depth at the proposed wellsite is

predicted to be about 6560 ft with zero datum at sea surface. The local gradient is less than 1° to the

north.

Seafloor Features. At the proposed MC 782-B wellsite, the local seafloor is smooth, featureless,

and appears stable. Several northwest-southeast trending seafloor faults are identified in the vicinity of the

proposed wellsite. The closest seafloor fault scarp lies about 1,560 ft to the southwest, exhibits a seafloor

relief of about 10 ft and is associated with seafloor gradient of less than 4°. Another seafloor fault is about

2,960 ft northeast of the proposed wellsite, and the seafloor scarp defined by this fault has maximum relief

of about 40 ft and a seafloor gradient of less than 10°. These faults are identified on SBP records and 3DX

seismic data. No seafloor faults will be penetrated by the proposed wellbore, and the seafloor fault scarps

meet the 75 m (245 ft) standoff distance as outlined by the BOEM in NTL No. 2008-G05.

Potential High-density Benthic Communities. Two areas of high seafloor multibeam

backscatter intensity indicative of possible hardground are located about 2,200 ft and 2,800 ft west of the

proposed MC 782-B wellsite. There is no geophysical evidence of hydrocarbon seepage sites or areas that

could potentially support high-density benthic communities within 2,000 ft of the proposed location.

Therefore, there is a negligible potential for high-density communities of benthic and/or chemosynthetic

organisms within 2,000 ft of the proposed wellsite, in accordance with BOEM NTL 2009-G40.

Man-Made Obstructions. A search of Fugro’s GIS database conducted in February 2013 and a

review of the SSS data from the high-resolution geophysical data set indicated closest man-made feature is

one existing pipeline (Enterprise 20-24” SEG#15153) ~2,920 ft north of the proposed wellsite.

The closest sonar targets (contacts # 37 and #38) were detected about 1,750 ft northeast and

~1,800 ft east of the proposed wellsite, respectively. These targets, and all the other targets farther from

the proposed wellsite, are interpreted as unidentified debris as outlined in the archaeological assessment

by C&C (Project No. 120578). Although no man-made features or other potentially hazardous seafloor

conditions are identified in the SSS data, we recommend that an ROV be used to inspect the seafloor at

the proposed wellsite immediately before spud-in to confirm that no seafloor obstructions have appeared

since the SSS survey was acquired.

Stratigraphy. The seafloor and five subsurface horizons (10, 20, 30, 40 and 60) were mapped to

divide the tophole section into five stratigraphic sequences (Sequence 1 through 5) of distinct seismic and

inferred lithologic character at the proposed wellbore. Predicted depths and thicknesses associated with

each of the mapped horizons and sequences are displayed on the attached Tophole Prognosis Chart for

the proposed Wellsite MC 782-B drilling location.

At the proposed wellbore, Sequence 1 is 290 ft thick and is divided into an upper 161 ft thick

interval of parallel-stratified marine clays and thin, fine-grained MTDs and a lower 129 ft thick interval of

sand-prone sediments. Sequence 2 is 200 ft thick and is comprised of mostly fine-grained sediments

interbedded with thin, fine-grained MTDs and possible thin sands. The upper 21 ft of Sequence 2 consists

of possible sand-prone channel and overbank deposits which are interpreted to be part of the Blue Unit

(Ostermeier et al., 2000 and Winker et al., 2000).

Sequence 3 is cumulatively about 1,551 ft thick and is interpreted to represent the informally

described Green Unit. The upper 246 ft of Sequence 3 consist of fine-grained MTDs interlayered with

fine-grained MTDs and possible sand-prone deposits. The middle 350 ft of Sequence 3 are comprised of

mostly fine-grained slope failure deposits interbedded with possible sand-prone sediments. The lower

955 ft of Sequence 3 consist of slope failure deposits consisting of sand-prone channel and overbank

deposits interbedded with fine-grianed MTDs. Sequence 4 is a 600 thick interval of faulted, fine-grained

sediments underlain by Sequence 5, which is composed of 785 ft of faulted, sand-prone channel and

overbank deposits interbedded with thin, fine-grained MTDs.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-2 4

Fault Penetrations. The proposed wellbore will not penetrate any buried faults. However the

sedimentary section within Sequences 4 and 5 is expected to be extensively fractured, and could create

secondary porosity and permeability that could cause drilling fluid loss to formation.

Gas Hydrate and Gas Hazards. Temperature and pressure conditions are favorable for the

presence of gas hydrates within the study area. The base of gas hydrate stability was modeled using the

fundamental gas hydrate phase equilibrium curve, which requires input for temperature, pressure, gas

mixture, and salinity (Sloan, 1990), and is estimated to be located within Sequence 3. Localized and

disseminated gas hydrates, if present, may occur above the base of has hydrate stability. Massive gas

hydrate accumulations at the proposed wellbore are not expected.

No high-amplitude anomalies interpreted to represent shallow gas will be penetrated in the tophole

section by a vertical wellbore at the proposed wellsite. Interpreted anomalies representing possible shallow

gas hazards in the tophole section within 3,000 ft of the proposed wellbore are located in Sequences 2

through 5. The closest amplitude anomalies to the proposed MC 782-B wellbore are located 372 ft to the

southeast within upper Sequence 2 and 1,050 ft to the southwest within Sequence 3. Because of the

sand-prone nature of lower Sequence 1 and upper Sequence 2, a low potential for shallow gas is assessed

for the intervals of these Sequences between 161 ft and 311 ft BML. Because of the presence of possible

sand-prone sediments within Sequences 3 and 5; a low potential for shallow gas is assessed for these

Sequences between 490 ft and 2,041 ft BML and between 2,641 ft and 3,426 ft BML, respectively.

Possible gas sands in the other stratigraphic units are located safely away from the borehole and should

not pose any hazard or constraint to drilling. Therefore, the remainder of the tophole section is assessed a

negligible potential for encountering significant gas accumulations.

Shallow-Water-Flow (SWF). A map presented by Pelletier and others (1999) shows the relative

magnitude of shallow-water-flow (SWF) hazards in the Northern Gulf of Mexico. On this map, the study

area falls within the moderate-risk zone. There are other reported cases of SWF in the general vicinity of

the study area. The MMS Internet Database indicates that SWF has occurred in the following wells in the

area: MC 696 (Blind Faith; very low severity event), MC 730-1 (moderate flow at 1,842 ft BML), MC 731-1

(low flow at 1,622 ft BML), MC 778-13 (low flow at 2,374 ft BML), MC 864-1 (moderate flow at 1,593 ft

BML). Based on these documented SWF events and the geologic conditions present within the study area,

we assess that the tophole section in MC 782 has the potential to be overpressured and that sand-prone

intervals, if penetrated, could cause a SWF event if not contained or otherwise mitigated.

Sequences 1 and 4 are comprised of mostly fine-grained sediments and are assessed a negligible

SWF potential. A lo w potential for SWF is assessed for the sand-prone intervals within lower

Sequence 1, lower Sequence 2, and Sequence 5. Sand-prone channel deposits within upper Sequence 2,

between 290 ft and 311 ft BML, are interpreted to be part of the Blue Unit sands (Ostermeier et al., 2000

and Winker et al., 2000) and are believed responsible for documented SWF occurrences at some wells in

the area. Therefore, upper Sequence 2 is assessed a moderate potential for SWF. Sequence 3 is

sand-prone and is interpreted to be part of the informally defined Green Unit sands inferred to have caused

SWF events at other wells in the area; therefore, all of Sequence 3 between 490 ft and 2,041 ft BML is

assessed a moderate potential for SWF at the proposed wellbore.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-2 5

We appreciate the opportunity to work with you on this project and look forward to continuing as

your geohazards consultants. If you have any questions concerning this assessment, please do not

hesitate to call us (713-369-5600).

Sincerely,

FUGRO GEOCONSULTING, INC.

Jennifer Katrib

Senior Geoscientist

Hunter Danque Bruce Samuel

Project Geoscientist Geoscience Group Manager

Attachments:

1. Water Depth and Seafloor Features, Dantzler Prospect, Block 782, Gulf of Mexico, Proposed

Wellsite MC 782-B (1:12,000)

2. Side-Scan Sonar Mosaic, Dantzler Prospect, Block 782, Mississippi Canyon Area, Proposed

Wellsite MC 782-B (1:12,000)

3. Multibeam Backscatter Rendering, Dantzler Prospect, Block 782, Mississippi Canyon, Proposed

Wellsite MC 782-B

4. Sub-seafloor Geologic Features, Dantzler Prospect, Block 782, Mississippi Canyon Area, Proposed

Wellsite MC 782-B (1:12,000)

5. Tophole Prognosis Chart, Proposed Wellsite MC 782-B, Dantzler Prospect, Block 782, Mississippi

Canyon Area, Gulf of Mexico

6. E-MANATEE 3DX Seismic Profile, Inline 14094, Proposed Wellsite MC 782-B, Dantzler Prospect,

Block 782, Mississippi Canyon Area, Gulf of Mexico

7. E-MANATEE 3DX Seismic Profile, Crossline 3766, Proposed Wellsite MC 782-B, Dantzler

Prospect, Block 782, Mississippi Canyon Area, Gulf of Mexico

8. Sub-bottom Profile, Line 135, Proposed Wellsite MC 782-B, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico

9. 3DX Seismic Power Spectrum, Proposed Wellsite MC 782-B, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico
FUGRO GEOCONSULTING, INC.

Letter Report No. 27. 2012-2526-3

13 February 2013

Noble Energy, Inc.

100 Glenborough

Houston, Texas 77069

Attention: Mr. Bill Hobbs

Wellsite Clearance Letter

Proposed Wellsite MC 782-C

Block 782, Mississippi Canyon Area

OCS-G-33757

Introduction. Fugro GeoConsulting, Inc. (FGCI) was contracted by Noble Energy Inc. (Noble) to

prepare a wellsite clearance letter addressing shallow hazards for proposed Wellsite MC 782-C in

Block 782, Mississippi Canyon Area (OCS-G-33757). The proposed well is planned to be vertical through

the tophole section and will be drilled by a dynamically positioned rig. This letter is intended to address

specific seafloor and shallow geologic conditions within 3,000 ft of the proposed wellsite to the top of salt

reflector (about 3,018 ft BML). Shallow geologic conditions at the proposed wellbore are summarized on

the attached Tophole Prognosis Chart. Annotated data examples of the nearest 3D exploration seismic

survey lines, a sub-bottom profiler line, and four 1:12,000-scale charts showing the proposed wellsite are

included. The 1:12,000-scale illustrations include a water depth and seafloor features chart, a side-scan

sonar mosaic, a multibeam backscatter chart, and a sub-seafloor geologic features chart. A 2,000 ft radius

circle around the proposed wellsite is shown, as per Bureau of Ocean Energy Management (BOEM) Notice

to Lessees (NTL) 2009-G40. Please refer to Fugro Report No. 27.2012-2526, “Shallow Geohazards

Assessment, Dantzler Prospect, Blocks 738 and 782, Mississippi Canyon Area, Gulf of Mexico,” for a

comprehensive assessment of shallow geohazards within Blocks 738 and 782, and a complete list of

references used in this investigation. Please refer to C&C Technologies, Inc. Project No. 120578,

“Archaeological Assessment Report, Blocks 737, 738, 782 Mississippi Canyon Area, Gulf of Mexico,” for a

description of the AUV geophysical data used in this report, as well as a comprehensive archaeological

assessment.

3-D Seismic Survey Parameters. A pre-stack, time-migrated 3DX seismic data volume was used

for this assessment. The 3DX survey is a subset of the WesternGeco “E-Manatee” reprocessing effort

completed in August 2007 and is based in part on the “Mississippi Canyon Phase 11 (Ultra)” survey

acquired in 1997 in a north-south orientation with a streamer length of 26,247 ft (8,000 m), 53 fold, 32.8 ft

(10 m +1.5m) sound source depth, and 41.01 ft (12.5 m) by 131 ft (40 m) bin spacing. The 3DX data

processing was performed by WesternGeco using Kirchhoff pre-stack time migration. The processed

volume has a bin size of 41.01 ft (12.5 m) by 65.6 ft (20 m) and a sample rate of 4 milliseconds (Chart 1).

The data exhibit no trace or sample decimation of the final processed volume. Inlines are oriented

east-west, have a numerical increment of one, and are spaced at intervals of 41.01 ft (12.5 m). Crosslines

are oriented north-south, have a numerical increment of 1, and are spaced at intervals of 65.6 ft (20 m).

The seismic data set follows North American polarity convention and demonstrates a balanced, zero-phase

wavelet based on analysis of the seafloor reflector, top of salt reflector, and low-impedance, high-amplitude

anomalies indicative of gas sands.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT 

MISSISSIPPI CANYON AREA, GULF OF MEXICO 

FGCI Report No. 27.2012-2526-3 2

3-D Seismic Frequency. Based on power spectra analysis of the 3DX seismic data at 50% 

power, the frequency bandwidth for the E-Manatee data between the seafloor to about 1.0 s is 

approximately 15-64 Hz. This frequency bandwidth corresponds to a limit of separability of 29 ft, assuming 

a dominant frequency of 45 Hz and an average velocity of 5,400 ft/s in the shallow section. Other details 

regarding the data descriptions and limitations are found in Fugro Report No. 27.2012-2526. 

High-Resolution Geophysical Data. A high-resolution geophysical survey was provided by Noble

for interpretation in this study. The survey was acquired by C&C in September 2012 utilizing an 

autonomous underwater vehicle (AUV) system. The survey grid consists of 49 primary north-south

trending tracklines spaced 200 m apart and 14 east-west trending tielines spaced 900 m apart. 

Navigational fixes (shot points) were recorded at 410 ft (125 m) intervals. Multibeam (MBES), side-scan 

sonar (SSS), and sub-bottom profiler (SBP) were acquired during this survey. For further details 

concerning the survey, please refer to C&C Project No. 120578 delivered to Noble Energy in October of 

2012.

Depth Conversions. Water column time-to-depth conversions for the 3DX seismic volume are

based on a velocity of about 1,480 ft/s. Water depths along AUV tracklines are based on a velocity model 

generated from real-time velocimeter data. Comparison of the AUV water depths, and the water depths of

the seismic volume showed the seismic was generally ~15 ft deeper. Sub-seafloor depths for the 3DX 

seismic data are based on an interval velocity volume provided by Noble, and sub-bottom profiler depths 

are based on a velocity of 5,250 ft/s.

.Offset Well Data. Noble provided well log data, daily drilling reports, scout tickets, and 

paleontological data for offset wells MC 782-1 (Caterpillar Deep) and MC 739-1 (Hilbert). Well logs from 

MC 782-1 (Caterpillar Deep), located about 1.6 mi southeast of the proposed wellbore and MC 739-1 

(Hilbert), located about 5.2 mi northeast of the proposed wellbore, were utilized to calibrate sediment 

interpretations from seismic data.

Graphics. A Water Depth and Seafloor Features page-size figure (1:12,000-scale) showing the 

proposed wellsite, water depth contours and seafloor features, accompanies this wellsite assessment. 

A 2,000 ft radius circle around the proposed wellsite is shown as per BOEM NTL No. 2009-G40. 

A Composite Side-Scan Sonar Mosaic and a Multibeam Backscatter chart (1:12,000-scale) showing the 

seafloor conditions in the vicinity of the wellsite are included. Shallow geologic conditions at the proposed 

wellsite are summarized on the attached Tophole Prognosis Chart. The nearest 3DX inline, 3DX crossline, 

and AUV SBP profiles are attached to illustrate shallow geologic conditions in the vicinity of the proposed 

location. A page-size 1:12,000-scale Sub-Seafloor Geologic Features Chart is also included to illustrate 

geologic conditions in the vicinity of the proposed wellbore. The 3DX Seismic Power Spectrum is included 

as an assessment of the frequency content of the 3DX seismic data at the proposed wellbore. 

Proposed Well Location. The surface location for proposed Wellsite MC 782-C is located in 

northern MC Block 782 as follows:

Proposed Wellsite MC 782-C

Block 782, Mississippi Canyon Area

UTM Zone 16, NAD 1927

X = 1,224,265 ft Y = 10,238,900 ft

Latitude: 28° 12' 31"N Longitude: 88° 17' 33"W

Nearest E-Manatee Inline 13993 Nearest E-Manatee Crossline 3723

4,585 ft FWL 6,260 ft FSL
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-3 3

Water Depth and Seafloor Gradient. The MBES water depth at the proposed wellsite is

predicted to be about 6542 ft with zero datum at sea surface. The local gradient is less than 1° to the

north.

Seafloor Features. At the proposed MC 782-C wellsite, the local seafloor is smooth, featureless,

and appears stable. Several north-northwest south-southeast trending seafloor faults are identified in the

vicinity of the proposed wellsite. The closest seafloor fault scarp lies about 320 ft to the west and the fault

dips away from the proposed wellbore. This seafloor fault scarp exhibits a seafloor relief of about 10 ft and

is associated with seafloor gradient of less than 4°. A cluster of seafloor fault scarps is located at least

2,400 ft west and southwest of the proposed wellsite, and the seafloor scarps defined by these faults have

maximum relief of about 40 ft and a seafloor gradient of less than 10°. These faults are identified on SBP

records and 3DX seismic data. No seafloor faults will be penetrated by the proposed wellbore, and the

seafloor fault scarps meet the 75 m (245 ft) standoff distance as outlined by the BOEM in NTL

No. 2008-G05.

Potential High-density Benthic Communities. One area of high seafloor multibeam backscatter

intensity indicative of possible hardground is located about 3,400 ft southwest of the proposed MC 782-C

wellsite. There is no geophysical evidence of hydrocarbon seepage sites or areas that could potentially

support high-density benthic communities within 2,000 ft of the proposed location. Therefore, there is a

negligible potential for high-density communities of benthic and/or chemosynthetic organisms within

2,000 ft of the proposed wellsite, in accordance with BOEM NTL 2009-G40.

Man-Made Obstructions. A search of Fugro’s GIS database conducted in February 2013 and a

review of the SSS data from the high-resolution geophysical data set indicated closest man-made feature is

one existing pipeline (Enterprise 20-24” SEG#15153) ~9,600 ft north of the proposed wellsite.

The closest sonar target (contact # 20) was detected about 2,800 ft southwest of the proposed

wellsite. This target, and all the other targets farther from the proposed wellsite, is interpreted as

unidentified debris as outlined in the archaeological assessment by C&C (Project No. 120578). Although

no man-made features or other potentially hazardous seafloor conditions are identified in the SSS data, we

recommend that an ROV be used to inspect the seafloor at the proposed wellsite immediately before

spud-in to confirm that no seafloor obstructions have appeared since the SSS survey was acquired.

Stratigraphy. The seafloor and five subsurface horizons (10, 20, 30, 40 and 60) were mapped to

divide the tophole section into five stratigraphic sequences (Sequence 1 through 5) of distinct seismic and

inferred lithologic character at the proposed wellbore. Predicted depths and thicknesses associated with

each of the mapped horizons and sequences are displayed on the attached Tophole Prognosis Chart for

the proposed Wellsite MC 782-C drilling location.

At the proposed wellbore, Sequence 1 is 274 ft thick and is divided into an upper 159 ft thick

interval of parallel-stratified marine clays and thin, fine-grained MTDs and a lower 115 ft thick interval of

sand-prone sediments. Sequence 2 is 244 ft thick and is comprised of mostly fine-grained sediments

interbedded with thin, fine-grained MTDs and possible thin sands. The upper 25 ft of Sequence 2 consists

of possible sand-prone channel and overbank deposits which are interpreted to be part of the Blue Unit

(Ostermeier et al., 2000 and Winker et al., 2000).

Sequence 3 is cumulatively about 1,460 ft thick and is interpreted to represent the informally

described Green Unit. The upper 481 ft of Sequence 3 consist of sand-prone sediments interbedded with

thin, fine-grained MTDs. The middle 520 ft of Sequence 3 are comprised of slope failure deposits

consisting of sand-prone channel and overbank deposits interbedded with fine-grained MTDs. The lower

459 ft of Sequence 3 consist of faulted, fine-grained sediments interbedded with possible thin sands.

Sequence 4 is a 690 ft thick interval of faulted, fine-grained sediments underlain by Sequence 5, which is

composed of 350 ft of faulted, sand-prone channel and overbank deposits interbedded with thin,

fine-grained MTDs.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-3 4

Fault Penetrations. One buried fault plane will intersect the proposed wellbore at about 2,699 ft

BML. This fault is presumed to be inactive and is not expected to present a constraint to drilling operations.

However the sedimentary section within Sequences 4 and 5 is expected to be extensively fractured, and

could create secondary porosity and permeability that could cause drilling fluid loss to formation.

Gas Hydrate and Gas Hazards. Temperature and pressure conditions are favorable for the

presence of gas hydrates within the study area. The base of gas hydrate stability was modeled using the

fundamental gas hydrate phase equilibrium curve, which requires input for temperature, pressure, gas

mixture, and salinity (Sloan, 1990), and is estimated to be located within Sequence 3. Localized and

disseminated gas hydrates, if present, may occur above the base of has hydrate stability. Massive gas

hydrate accumulations at the proposed wellbore are not expected.

No high-amplitude anomalies interpreted to represent shallow gas will be penetrated in the tophole

section by a vertical wellbore at the proposed wellsite. Interpreted anomalies representing possible shallow

gas hazards in the tophole section within 3,000 ft of the proposed wellbore are located in Sequences 2

through 5. The closest amplitude anomalies to the proposed MC 782-C wellbore are located 345 ft to the

southwest within upper Sequence 2 and 1,100 ft to the north-northeast within Sequence 3. Because of the

sand-prone nature of lower Sequence 1 and upper Sequence 2, a low potential for shallow gas is assessed

for the intervals of these Sequences between 159 ft and 299 ft BML. Because of the presence of possible

sand-prone sediments within Sequences 3 and 5; a low potential for shallow gas is assessed for these

Sequences between 518 ft and 1,978 ft BML and between 2,668 ft and 3,018 ft BML, respectively.

Possible gas sands in the other stratigraphic units are located safely away from the borehole and should

not pose any hazard or constraint to drilling. Therefore, the remainder of the tophole section is assessed a

negligible potential for encountering significant gas accumulations.

Shallow-Water-Flow (SWF). A map presented by Pelletier and others (1999) shows the relative

magnitude of shallow-water-flow (SWF) hazards in the Northern Gulf of Mexico. On this map, the study

area falls within the moderate-risk zone. There are other reported cases of SWF in the general vicinity of

the study area. The MMS Internet Database indicates that SWF has occurred in the following wells in the

area: MC 696 (Blind Faith; very low severity event), MC 730-1 (moderate flow at 1,842 ft BML), MC 731-1

(low flow at 1,622 ft BML), MC 778-13 (low flow at 2,374 ft BML), MC 864-1 (moderate flow at 1,593 ft

BML). Based on these documented SWF events and the geologic conditions present within the study area,

we assess that the tophole section in MC 782 has the potential to be overpressured and that sand-prone

intervals, if penetrated, could cause a SWF event if not contained or otherwise mitigated.

Sequences 1 and 4 are comprised of mostly fine-grained sediments and are assessed a negligible

SWF potential. A lo w potential for SWF is assessed for the sand-prone intervals within lower

Sequence 1, lower Sequence 2, and Sequence 5. Sand-prone channel deposits within upper Sequence 2,

between 274 ft and 299 ft BML, are interpreted to be part of the Blue Unit sands (Ostermeier et al., 2000

and Winker et al., 2000) and are believed responsible for documented SWF occurrences at some wells in

the area. Therefore, upper Sequence 2 is assessed a moderate potential for SWF. Sequence 3 is

sand-prone and is interpreted to be part of the informally defined Green Unit sands inferred to have caused

SWF events at other wells in the area; therefore, all of Sequence 3 between 518 ft and 1,978 ft BML is

assessed a moderate potential for SWF at the proposed wellbore.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-3 5

We appreciate the opportunity to work with you on this project and look forward to continuing as

your geohazards consultants. If you have any questions concerning this assessment, please do not

hesitate to call us (713-369-5600).

Sincerely,

FUGRO GEOCONSULTING, INC.

Jennifer Katrib

Senior Geoscientist

Hunter Danque Bruce Samuel

Project Geoscientist Geoscience Group Manager

Attachments:

1. Water Depth and Seafloor Features, Dantzler Prospect, Block 782, Gulf of Mexico, Proposed

Wellsite MC 782-C (1:12,000)

2. Side-Scan Sonar Mosaic, Dantzler Prospect, Block 782, Mississippi Canyon Area, Proposed

Wellsite MC 782-C (1:12,000)

3. Multibeam Backscatter Rendering, Dantzler Prospect, Block 782, Mississippi Canyon, Proposed

Wellsite MC 782-C

4. Sub-seafloor Geologic Features, Dantzler Prospect, Block 782, Mississippi Canyon Area, Proposed

Wellsite MC 782-C (1:12,000)

5. Tophole Prognosis Chart, Proposed Wellsite MC 782-C, Dantzler Prospect, Block 782, Mississippi

Canyon Area, Gulf of Mexico

6. E-MANATEE 3DX Seismic Profile, Inline 13993, Proposed Wellsite MC 782-C, Dantzler Prospect,

Block 782, Mississippi Canyon Area, Gulf of Mexico

7. E-MANATEE 3DX Seismic Profile, Crossline 3723, Proposed Wellsite MC 782-C, Dantzler

Prospect, Block 782, Mississippi Canyon Area, Gulf of Mexico

8. Sub-bottom Profile, Line 132, Proposed Wellsite MC 782-C, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico

9. 3DX Seismic Power Spectrum, Proposed Wellsite MC 782-C, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico
FUGRO GEOCONSULTING, INC.

Letter Report No. 27. 2012-2526-6

8 March 2013

Noble Energy, Inc.

100 Glenborough

Houston, Texas 77069

Attention: Mr. Bill Hobbs

Wellsite Clearance Letter

Proposed Wellsite MC 782-D

Block 782, Mississippi Canyon Area

OCS-G-33757

Introduction. Fugro GeoConsulting, Inc. (FGCI) was contracted by Noble Energy Inc. (Noble) to

prepare a wellsite clearance letter addressing shallow hazards for proposed Wellsite MC 782-D in

Block 782, Mississippi Canyon Area (OCS-G-33757). The proposed well is planned to be vertical through

the tophole section and will be drilled by a dynamically positioned rig. This letter is intended to address

specific seafloor and shallow geologic conditions within 3,000 ft of the proposed wellsite to the top of salt

reflector (about 3,220 ft BML). Shallow geologic conditions at the proposed wellbore are summarized on

the attached Tophole Prognosis Chart. Annotated data examples of the nearest 3D exploration seismic

survey lines, a sub-bottom profiler line, and four 1:12,000-scale charts showing the proposed wellsite are

included. The 1:12,000-scale illustrations include a water depth and seafloor features chart, a side-scan

sonar mosaic, a multibeam backscatter chart, and a sub-seafloor geologic features chart. A 2,000 ft radius

circle around the proposed wellsite is shown, as per Bureau of Ocean Energy Management (BOEM) Notice

to Lessees (NTL) 2009-G40. Please refer to Fugro Report No. 27.2012-2526, “Shallow Geohazards

Assessment, Dantzler Prospect, Blocks 738 and 782, Mississippi Canyon Area, Gulf of Mexico,” for a

comprehensive assessment of shallow geohazards within Blocks 738 and 782, and a complete list of

references used in this investigation. Please refer to C&C Technologies, Inc. Project No. 120578,

“Archaeological Assessment Report, Blocks 737, 738, 782 Mississippi Canyon Area, Gulf of Mexico,” for a

description of the AUV geophysical data used in this report, as well as a comprehensive archaeological

assessment.

3-D Seismic Survey Parameters. A pre-stack, time-migrated 3DX seismic data volume was used

for this assessment. The 3DX survey is a subset of the WesternGeco “E-Manatee” reprocessing effort

completed in August 2007 and is based in part on the “Mississippi Canyon Phase 11 (Ultra)” survey

acquired in 1997 in a north-south orientation with a streamer length of 26,247 ft (8,000 m), 53 fold, 32.8 ft

(10 m +1.5m) sound source depth, and 41.01 ft (12.5 m) by 131 ft (40 m) bin spacing. The 3DX data

processing was performed by WesternGeco using Kirchhoff pre-stack time migration. The processed

volume has a bin size of 41.01 ft (12.5 m) by 65.6 ft (20 m) and a sample rate of 4 milliseconds. The data

exhibit no trace or sample decimation of the final processed volume. Inlines are oriented east-west, have a

numerical increment of one, and are spaced at intervals of 41.01 ft (12.5 m). Crosslines are oriented northsouth, have a numerical increment of 1, and are spaced at intervals of 65.6 ft (20 m). The seismic data set

follows North American polarity convention and demonstrates a balanced, zero-phase wavelet based on

analysis of the seafloor reflector, top of salt reflector, and low-impedance, high-amplitude anomalies

indicative of gas sands.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-6 2

3-D Seismic Frequency. Based on power spectra analysis of the 3DX seismic data at 50%

power, the frequency bandwidth for the E-Manatee data between the seafloor to about 1.0 s is

approximately 15-64 Hz. This frequency bandwidth corresponds to a limit of separability of 29 ft, assuming

a dominant frequency of 45 Hz and an average velocity of 5,400 ft/s in the shallow section. Other details

regarding the data descriptions and limitations are found in Fugro Report No. 27.2012-2526.

High-Resolution Geophysical Data. A high-resolution geophysical survey was provided by Noble

for interpretation in this study. The survey was acquired by C&C in September 2012 utilizing an

autonomous underwater vehicle (AUV) system. The survey grid consists of 49 primary north-south

trending tracklines spaced 200 m apart and 14 east-west trending tielines spaced 900 m apart.

Navigational fixes (shot points) were recorded at 410 ft (125 m) intervals. Multibeam (MBES), side-scan

sonar (SSS), and sub-bottom profiler (SBP) were acquired during this survey. For further details

concerning the survey, please refer to C&C Project No. 120578 delivered to Noble Energy in October of

2012.

Depth Conversions. Water column time-to-depth conversions for the 3DX seismic volume are

based on a velocity of about 1,480 m/s. Water depths along AUV tracklines are based on a velocity model

generated from real-time velocimeter data. Comparison of the AUV water depths, and the water depths of

the seismic volume showed the seismic was generally ~15 ft deeper. Sub-seafloor depths for the 3DX

seismic data are based on an interval velocity volume provided by Noble, and sub-bottom profiler depths

are based on a velocity of 5,250 ft/s.

.Offset Well Data. Noble provided well log data, daily drilling reports, scout tickets, and

paleontological data for offset wells MC 782-1 (Caterpillar Deep) and MC 739-1 (Hilbert). Well logs from

MC 782-1 (Caterpillar Deep), located about 3 mi southeast of the proposed wellbore and MC 739-1

(Hilbert), located about 4.2 mi east-northeast of the proposed wellbore, were utilized to calibrate sediment

interpretations from seismic data.

Graphics. A Water Depth and Seafloor Features page-size figure (1:12,000-scale) showing the

proposed wellsite, water depth contours and seafloor features, accompanies this wellsite assessment.

A 2,000 ft radius circle around the proposed wellsite is shown as per BOEM NTL No. 2009-G40. SideScan Sonar Mosaic and Multibeam Backscatter charts (1:12,000-scale) showing the seafloor conditions in

the vicinity of the wellsite are included. Shallow geologic conditions at the proposed wellsite are

summarized on the attached Tophole Prognosis Chart. The nearest 3DX inline, 3DX crossline, and AUV

SBP profiles are attached to illustrate shallow geologic conditions in the vicinity of the proposed location. A

page-size 1:12,000-scale Sub-Seafloor Geologic Features Chart is also included to illustrate geologic

conditions in the vicinity of the proposed wellbore. The 3DX Seismic Power Spectrum is included as an

assessment of the frequency content of the 3DX seismic data at the proposed wellbore.

Proposed Well Location. The surface location for proposed Wellsite MC 782-D is located in

northern MC Block 782 as follows:

Proposed Wellsite MC 782-D

Block 782, Mississippi Canyon Area

UTM Zone 16, NAD 1927

X = 1,224,918 ft Y = 10,247,903 ft

Latitude: 28° 14' 00"N Longitude: 88° 17' 26"W

Nearest E-Manatee Inline 14130 Nearest E-Manatee Crossline 3739

5,238 ft FWL 577 ft FNL
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-6 3

Water Depth and Seafloor Gradient. The MBES water depth at the proposed wellsite is

predicted to be about 6576 ft with zero datum at sea surface. The local gradient is less than 1° to the east.

Seafloor Features. At the proposed MC 782-D wellsite, the local seafloor is smooth, featureless,

and appears stable. Two northwest-southeast trending seafloor faults are identified in the vicinity of the

proposed wellsite. The closest seafloor fault scarp lies about 2,130 ft to the southwest, exhibits a seafloor

relief of about 10 ft and is associated with seafloor gradient of less than 4°. Another seafloor fault is about

2,300 ft northeast of the proposed wellsite, and the seafloor scarp defined by this fault has maximum relief

of about 40 ft and a seafloor gradient of less than 10°. These faults are identified on SBP records and 3DX

seismic data. No seafloor faults will be penetrated by the proposed wellbore, and the seafloor fault scarps

meet the 75 m (245 ft) standoff distance as outlined by the BOEM in NTL No. 2008-G05.

Potential High-density Benthic Communities. Two areas of high seafloor multibeam

backscatter intensity indicative of possible hardground are located about 2,030 ft and 2,750 ft southwest of

the proposed MC 782-D wellsite. There is no geophysical evidence of hydrocarbon seepage sites or areas

that could potentially support high-density benthic communities within 2,000 ft of the proposed location.

Therefore, there is a negligible potential for high-density communities of benthic and/or chemosynthetic

organisms within 2,000 ft of the proposed wellsite, in accordance with BOEM NTL 2009-G40.

Man-Made Obstructions. A search of Fugro’s GIS database conducted in February 2013 and a

review of the SSS data from the high-resolution geophysical data set indicated closest man-made feature is

one existing pipeline (Enterprise 20-24” SEG#15153) 577 ft north of the proposed wellsite.

The closest sonar target (contact # 37) was detected about 3,180 ft southeast of the proposed

wellsite. This target, and all the other targets farther from the proposed wellsite, are interpreted as

unidentified debris as outlined in the archaeological assessment by C&C (Project No. 120578). Although

no man-made features or other potentially hazardous seafloor conditions are identified in the SSS data, we

recommend that an ROV be used to inspect the seafloor at the proposed wellsite immediately before

spud-in to confirm that no seafloor obstructions have appeared since the SSS survey was acquired.

Stratigraphy. The seafloor and five subsurface horizons (10, 20, 30, 40 and 60) were mapped to

divide the tophole section into five stratigraphic sequences (Sequence 1 through 5) of distinct seismic and

inferred lithologic character at the proposed wellbore. Predicted depths and thicknesses associated with

each of the mapped horizons and sequences are displayed on the attached Tophole Prognosis Chart for

the proposed wellsite MC 782-D drilling location.

At the proposed wellbore, Sequence 1 is 275 ft thick and is divided into an upper 165 ft thick

interval of parallel-stratified marine clays and thin, fine-grained MTDs and a lower 110 ft thick interval of

sand-prone sediments. Sequence 2 is 200 ft thick and is comprised of mostly fine-grained sediments

interbedded with thin, fine-grained MTDs and possible thin sands. The upper 25 ft of Sequence 2 consists

of possible sand-prone channel and overbank deposits which are interpreted to be part of the Blue Unit

(Ostermeier et al., 2000 and Winker et al., 2000).

Sequence 3 is cumulatively about 1,730 ft thick and is interpreted to represent the informally

described Green Unit. The upper 270 ft of Sequence 3 consist of fine-grained MTDs interbedded with

possible sand-prone deposits. The middle 675 ft of Sequence 3 are comprised of slope failure deposits

consisting of sand-prone channel and overbank deposits interbedded with fine-grained MTDs. The lower

785 ft of Sequence 3 consist of mostly fine-grained slope failure deposits with possible sand-prone

sediment blocks. Sequence 4 is a 475 ft thick interval of faulted, fine-grained sediments underlain by

Sequence 5, which is composed of 540 ft of faulted, sand-prone channel and overbank deposits

interbedded with thin, fine-grained MTDs.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-6 4

Fault Penetrations. One buried fault plane will intersect the proposed wellbore at about 2,940 ft

BML. This fault is presumed to be inactive and is not expected to present a constraint to drilling operations.

However the sedimentary section within Sequences 4 and 5 is expected to be extensively fractured, and

could create secondary porosity and permeability that could cause drilling fluid loss to formation.

Gas Hydrate and Gas Hazards. Temperature and pressure conditions are favorable for the

presence of gas hydrates within the study area. The base of gas hydrate stability was modeled using the

fundamental gas hydrate phase equilibrium curve, which requires input for temperature, pressure, gas

mixture, and salinity (Sloan, 1990), and is estimated to be located within Sequence 3. Localized and

disseminated gas hydrates, if present, may occur above the base of has hydrate stability. Massive gas

hydrate accumulations at the proposed wellbore are not expected.

No high-amplitude anomalies interpreted to represent shallow gas will be penetrated in the tophole

section by a vertical wellbore at the proposed wellsite. Interpreted anomalies representing possible shallow

gas hazards in the tophole section within 3,000 ft of the proposed wellbore are located in Sequences 2

through 5. The closest amplitude anomalies to the proposed MC 782-D wellbore are located 552 ft to the

southwest and 507 ft to the southeast within upper Sequence 2. Because of the sand-prone nature of

lower Sequence 1 and upper Sequence 2, a low potential for shallow gas is assessed for the intervals of

these Sequences between 165 ft and 300 ft BML. Because of the presence of possible sand-prone

sediments within Sequences 3 and 5; a low potential for shallow gas is assessed for these Sequences

between 475 ft and 2,205 ft BML and between 2,680 ft and 3,220 ft BML, respectively. Possible gas sands

in the other stratigraphic units are located safely away from the borehole and should not pose any hazard

or constraint to drilling. Therefore, the remainder of the tophole section is assessed a negligible potential

for encountering significant gas accumulations.

Shallow-Water-Flow (SWF). A map presented by Pelletier and others (1999) shows the relative

magnitude of shallow-water-flow (SWF) hazards in the Northern Gulf of Mexico. On this map, the study

area falls within the moderate-risk zone. There are other reported cases of SWF in the general vicinity of

the study area. The BOEM Internet Database indicates that SWF has occurred in the following wells in the

area: MC 696 (Blind Faith; very low severity event), MC 730-1 (moderate flow at 1,842 ft BML), MC 731-1

(low flow at 1,622 ft BML), MC 778-13 (low flow at 2,374 ft BML), MC 864-1 (moderate flow at 1,593 ft

BML). Based on these documented SWF events and the geologic conditions present within the study area,

we assess that the tophole section in MC 782 has the potential to be overpressured and that sand-prone

intervals, if penetrated, could cause a SWF event if not contained or otherwise mitigated.

Sequences 1 and 4 are comprised of mostly fine-grained sediments and are assessed a negligible

SWF potential. A lo w potential for SWF is assessed for the sand-prone intervals within lower

Sequence 1, lower Sequence 2, and Sequence 5. Sand-prone channel deposits within upper Sequence 2,

between 275 ft and 300 ft BML, are interpreted to be part of the Blue Unit sands (Ostermeier et al., 2000

and Winker et al., 2000) and are believed responsible for documented SWF occurrences at some wells in

the area. Therefore, upper Sequence 2 is assessed a moderate potential for SWF. Sequence 3 is

sand-prone and is interpreted to be part of the informally defined Green Unit sands inferred to have caused

SWF events at other wells in the area; therefore, all of Sequence 3 between 475 ft and 2,205 ft BML is

assessed a moderate potential for SWF at the proposed wellbore.
NOBLE ENERGY INC.

SHALLOW HAZARDS ASSESSMENT, DANTZLER PROSPECT

MISSISSIPPI CANYON AREA, GULF OF MEXICO

FGCI Report No. 27.2012-2526-6 5

We appreciate the opportunity to work with you on this project and look forward to continuing as

your geohazards consultants. If you have any questions concerning this assessment, please do not

hesitate to call us (713-369-5600).

Sincerely,

FUGRO GEOCONSULTING, INC.

Jennifer Katrib

Senior Geoscientist

Hunter Danque Bruce Samuel

Project Geoscientist Geoscience Group Manager

Attachments:

1. Water Depth and Seafloor Features, Dantzler Prospect, Block 782, Gulf of Mexico, Proposed

Wellsite MC 782-D (1:12,000)

2. Side-Scan Sonar Mosaic, Dantzler Prospect, Block 782, Mississippi Canyon Area, Proposed

Wellsite MC 782-D (1:12,000)

3. Multibeam Backscatter Rendering, Dantzler Prospect, Block 782, Mississippi Canyon, Proposed

Wellsite MC 782-D

4. Sub-seafloor Geologic Features, Dantzler Prospect, Block 782, Mississippi Canyon Area, Proposed

Wellsite MC 782-D (1:12,000)

5. Tophole Prognosis Chart, Proposed Wellsite MC 782-D, Dantzler Prospect, Block 782, Mississippi

Canyon Area, Gulf of Mexico

6. 3DX Seismic Profile, Inline 14130, Proposed Wellsite MC 782-D, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico

7. 3DX Seismic Profile, Crossline 3739, Proposed Wellsite MC 782-D, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico

8. Sub-bottom Profile, Line 133-e-1, Proposed Wellsite MC 782-D, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico

9. 3DX Seismic Power Spectrum, Proposed Wellsite MC 782-D, Dantzler Prospect, Block 782,

Mississippi Canyon Area, Gulf of Mexico
Section D

Hydrogen Sulfide Information

A. Concentration

Noble Energy, Inc. does not anticipate encountering any H2S during the proposed operations.

B. Classification

In accordance with Title 30 CFR 250.490(c) and NTL No. 2003-G17, Noble requests that Mississippi

Canyon 738 and 782 be classified by the BOEM as H2S absent.

Noble Energy, Inc. Page D-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Section E

Biological, Physical and Socioeconomic Information

A. Chemosynthetic Communities Report

Activities proposed in this plan could disturb seafloor areas in deepwater, therefore, a report described in

Attachment A of NTL No. 2009-G40 "Deepwater Benthic Communities" is provided below:

MAPS

Submitted under separate cover are maps prepared using high resolution seismic information and/or 3-D

seismic data depicting bathymetry, seafloor and shallow geological features, surface location of proposed

well(s), and a radius circle of 2,000 feet around each such location.

ANALYSIS

Using high-resolution seismic information and/or 3-D seismic information, all seafloor features and areas

that could be disturbed by the activities proposed in this plan have been identified. The likelihood of

these proposed activities disturbing these seafloor and shallow geologic features is discussed in the

following summary statement:

No Associated Anchors – No Disturbances within 2,000 Feet of Chemosynthetic Communities

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

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

1. Sensitive Underwater Features

The activities proposed in this plan will not take place within 500 feet of any identified topographic

feature; therefore topographic features information is not required.

2. Marine Sanctuaries

Mississippi Canyon 738 and 782 are not located within 100 feet of any pinnacle trend feature with

vertical relief equal to or greater than 8 feet; therefore, live bottom information is not required.

B. Topographic Features Map

Activities proposed in this EP do not fall within 305 meters (1,000 feet) of the “no activity zone”,

therefore no map is required.

C. Topographic Features Statement (Shunting)

All activities proposed under this EP will be conducted outside all Topographic Feature Protective

Zones, therefore shunting of drill cuttings and drilling fluids is not required.

D. Live Bottoms (Pinnacle Trend) Map

Mississippi Canyon 738 and 782 are not located within 61 meters (200 feet) of any pinnacle trend

feature with vertical relief equal to or greater than 8 feet; therefore, live bottom information is not

required.

E. Live Bottoms (Low Relief) Map

Mississippi Canyon 738 and 782 are not located within 100 feet of any pinnacle trend feature with

vertical relief equal to or greater than 8 feet; therefore, live bottom (low relief) maps are not required.

Noble Energy, Inc. Page E-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
F. Potentially Sensitive Biological Features

Mississippi Canyon 738 and 782 are not located within 30 meters (100 feet) of potentially sensitive

biological features; therefore, biologically sensitive area maps are not required.

G. Remotely Operated Vehicle (ROV) Monitoring Survey Plan

Pursuant to NTL No. 2008-G06, operators may be required to conduct remotely operated vehicle (ROV)

surveys during pre-spudding and post-drilling operations for the purpose of biological and physical

observations.

Mississippi Canyon 738 and 782 fall within Grid No. 17, an area which BOEM classifies as having

inadequate ROV survey coverage; therefore a plan for an ROV monitoring survey is required.

Surveys will be conducted immediately prior and upon completion of drilling operations.

A rig based ROV equipped with video imaging capabilities will be used. 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.

Biological and physical observations as described in the subject NTL and Form BOEM-141 will be made

prior to commencing drilling operations and also following the completion of drilling operations, but

prior to moving the rig off location. The observations will be documented using Form BOEM-141 or a

facsimile and submitted to the BOEM within 60 days after the second survey is completed.

H. Threatened and Endangered Species Information, Critical Habitat, and Marine Mammal

Information

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

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

or destroy or adversely modify its designated critical habitat.

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

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

presence of federally listed threatened or endangered species and critical habitat designated under the

ESA and marine mammals protected under the Marine Mammal Protection Act (MMPA) in the area of

proposes activities under this plan.

NOAA Fisheries currently lists the Sperm Whale, Leatherback Turtle, Green Turtle, Hawksbill Turtle,

and the Kemp’s Ridley Turtle as endangered and the Loggerhead Turtle and Gulf Sturgeon as threatened.

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

Continental Shelf, however, it is possible that one or more of these species could be seen in the area of

our operations.

I. Archaeological Report

An Archaeological Survey for Mississippi Canyon 738 and 782 was performed by C&C Technologies

Survey Services and it is being submitted with this plan.

Noble Energy, Inc. Page E-2

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Section F

Waste and Discharge Information

A. Projected Generated Wastes & Projected Ocean Discharges

See Table 1 below

All discharges associated with operations proposed in this Exploration Plan will be in accordance with

regulations implemented by Bureau of Ocean Energy Management (BOEM), U. S. Coast Guard (USCG)

and the U.S. Environmental Protection Agency (EPA).

Projected generated waste Projected ocean discharges

Projected

Downhole

Disposal

Type of Waste Composition

Projected

Amount

Discharge

rate Discharge Method

Answer

yes or no

Will drilling occur ? If yes, you should list muds and cuttings

EXAMPLE: Cuttings wetted with synthetic

based fluid

Cuttings generated while

using synthetic based drilling

fluid. X bbl/well

X bbl/day/

well discharge overboard No

Water-based drilling fluid Seawater 20476 2047 Riserless at sea floor No

Synthetic based drilling fluids or muds Internal Olefine 217 2.3

Discharge overboard

with cuttings No

Cuttings wetted with water-based fluid

Cuttings generated while

using water based drilling

fluid. 4989 498 Riserless at sea floor No

Cuttings wetted with synthetic-based fluid

Cutting generated while

using synthetic based

drilling fluid. 3152 33 Discharge overboard No

Will humans be there? If yes, expect conventional waste

EXAMPLE: Sanitary waste water

Sanitary waste from living

quarters X bbl/well X bbl/hr/well

chlorinate and discharge

overboard No

Domestic waste – gray water Food waste disposal 300 lbs/day 30 lbs/min Discharge overboard No

Sanitary waste Human Waste

2,312

gal/day 96.3 GPH Chlorinated No

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

Deck Drainage Rain Water N/A N/A Closed loop system No

Will you conduct well treatment, completion, or workover?

Well treatment fluids

8.6 ppg potassium chloride

based well treatment fluid

500

bbls/well

500 bbl

treatment discharge overboard No

Well completion fluids

12.4 lb/gal Calcium

Chloride/Calcium Bromide 10,000 bbls 500 bbls

< 500 bbls discharge

overboard. Remainder

- 25% lost to formation

during completion/ 75%

reclaimed and sold back

to vendor No

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

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

activity.

Desalinization unit discharge Seawater 46,656/day 1,950 GPH Discharge overboard No

Blowout prevent fluid Erifon

1,500 gal at

4% Stack No

Ballast water Seawater

72,000

gal/day 1,200 GPM Pump No

Bilge water N/A N/A N/A N/A No

Excess cement at seafloor Type 1 Cement 120 BBLS 8 BPM Pump No

Fire water Seawater

0 bbls – only

use in case

of fire 800 GPM Discharge overboard No

Cooling water Seawater

5,760,000

gal/day

240,000

gal/hr Pump No

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

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

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

Noble Energy, Inc. Page F-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Noble Energy, Inc. Page G-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757

Section G

Air Emissions Information

A. Emissions Worksheets and Screening Questions

Screen Procedures for EP’s Yes No

Is any calculated Complex Total (CT) Emission amount (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)?

X

Do your emission calculations include any emission reduction measures or modified

emission factors?

X

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

Do you expect to encounter H2S at concentrations greater than 20 parts per million

(ppm)?

X

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

any proposed well?

X

Do you propose to burn produced hydrocarbon liquids? X

If you answer no to all of the above screening questions, then provide the following:

There are no existing facilities or activities co-located with the currently proposed activities,

therefore the Complex Total Emissions are the same as the Plan Emissions and are provided

in the table below.

Air Pollutant

Plan

Emission

Amounts1

(tons)

Calculated

Exemption

Amounts2

(tons)

Calculated

Complex Total

Emission

Amounts3

(tons)

Carbon Monoxide (CO) 462.36 59928.50 462.36

Particular matter (PM) 61.65 2464.20 61.65

Sulphur dioxide (SO2) 282.81 2464.20 282.81

Nitrogen oxides (NOx) 2119.14 2464.20 2119.14

Volatile organic compounds (VOC) 63.57 2464.20 63.57

1For activities proposed in your EP, list the projected emissions calculated from the worksheets.

2List the exemption amounts for your proposed activities calculated by using the formulas in 30 CFR 250.303(d). 3List the complex

total emissions associated with your proposed activities calculated from the worksheets

Contact Information:

Name: Nicole Bueno

Email: NBueno@nobleenergyinc.com

Office Number: 281-872-2593
Section H

Oil Spill Information

A. Oil Spill Response Planning

Noble Energy, Inc.’s (BOEM Operator Number 02237) Regional Oil Spill Response Plan (OSRP) was

approved on March 28, 2013. Activities proposed in this EP will be covered by the Regional OSRP in

accordance with 30 CFR 254.

Surface Containment – In the event of an oil spill, resources have been contracted and are available to

deploy ocean boom to collect product on the water and direct it to skimmers for recovery or to conduct

in-situ burn operations. By utilizing multiple contractors over 100,000 feet of ocean boom is available for

use within 48 hours.

If product continues to move closer to shore both collection and protection booming strategies can be

utilized to minimize impact to the Coastal Zone. In the near-shore environment over 250,000 feet of 18”

hard boom is available within 48 hours. The primary focus is to collect and/or remove the product from

the surface of the water via mechanical recovery and/or in-situ burning.

The final protection is beach boom and would need to be deployed very strategically based on the

conditions observed and the movement of the product. Utilizing the same 48 hour window of availability

5,000 feet is available. Based on the WCD information Plaquemines, LA has an 11% chance of impact

within the first 30 days. All other parishes on the coastline have a 2% or less chance in the same period.

Noble Energy has taken extra steps to ensure resources are available quickly from around the Gulf of

Mexico to respond to a release from Mississippi Canyon 738 & 782 and to the extent possible minimize

potential impacts to the Coastal Zone by engaging the product early in the offshore and near-shore

environments.

B. Spill Response Sites

Primary Response Equipment Location Preplanned Staging Location

Houma/ Venice/ Belle Chasse, LA Houma/ Fourchon/ Venice,

LA; Theodore, AL

C. OSRO Information

Noble has two equipment providers, Clean Gulf Associates (CGA) and Marine Spill Response

Corporation (MSRC). The Marine Spill Response Corporation’s (MSRC) STARS network will provide

closest available personnel, as well as an MSRC supervisor to operate the equipment.

Noble Energy, Inc. Page H-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
D. Worst-Case Scenario Comparison

Category

Regional OSRP

WCD

EP

WCD

Type of Activity Drilling Drilling

Facility Location

(Area/Block) MC 699 MC 782

Facility Designation Location D Location A

Distance to Nearest

Shoreline (miles) 80 74

Volume

Storage tanks (total)

Uncontrolled blowout

Total Volume 265,500 173,214

Type of Oil(s)

(crude, condensate, diesel) Crude Crude

API Gravity 30.95° 26.30°

The Regional OSRP for exploratory worst case discharge was reviewed and accepted under plan R-5205

for the Mississippi Canyon Block 699.

Since Noble Energy Inc. has the capability to respond to the worst-case spill scenario included in our

regional OSRP approved on March 28, 2013 and since the worst-case scenario determined for our EP

does not replace the appropriate worst-case scenario in our regional OSRP, Noble Energy Inc. has

certified that it 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 this EP.

E. Oil Spill Response Discussion

See attachment H-1.

Noble Energy, Inc. Page H-2

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Page 1 of 18 

SPILL RESPONSE DISCUSSION 

For the purpose of NEPA and Coastal Zone Management Act analysis, the largest spill volume 

originating from the proposed activity would be a well blowout during drilling operations, 

estimated to be 173,214 barrels of crude oil with an API gravity of 26.3°. 

Land Segment and Resource Identification

Trajectories of a spill and the probability of it impacting a land segment have been projected 

utilizing information in the BSEE Oil Spill Risk Analysis Model (OSRAM) for the Central and 

Western Gulf of Mexico available on the BSEE website. The results are shown in Figure 1. The 

BSEE OSRAM identifies an 11% probability of impact to the shorelines of Plaquemines Parish, 

Louisiana within 30 days. Plaquemines Parish includes Barataria Bay, the Mississippi River 

Delta, Breton Sound and the affiliated islands and bays. This region is an extremely sensitive 

habitat and serves as a migratory, breeding, feeding and nursery habitat for numerous species of 

wildlife. Beaches in this area vary in grain particle size and can be classified as fine sand, shell or 

perched shell beaches. Sandy and muddy tidal flats are also abundant. 

Response

Noble Energy, Inc. will make every effort to respond to the Worst Case Discharge as effectively 

as practicable. A description of the response equipment under contract to contain and recover the 

Worst Case Discharge is shown in Figure 2.

Using the estimated chemical and physical characteristics of crude oil, an ADIOS weathering 

model was run on a similar product from the ADIOS oil database. The results indicate 20% or 

approximately 34,643 barrels of crude oil would be evaporated/dispersed within 24 hours, with 

approximately 138,571 barrels remaining. 

Spill Response MC 782, Well Location A Barrels of Oil 

WCD Volume 173,214 

Less 20% natural evaporation/dispersion 34,643 

Remaining volume 138,571 

Figure 2 outlines equipment, personnel, materials and support vessels as well as temporary 

storage equipment available to respond to a spill of approximately 138,571 barrels. The volume 

accounts for the amount remaining after evaporation/dispersion at 24 hours. The list estimates 

individual times needed for procurement, load out, travel time to the site and deployment. Figure 

2 also indicates how operations will be supported. 

Noble Energy, Inc.’s Oil Spill Response Plan includes alternative response technologies such as 

dispersants and in-situ burn. Strategies will be decided by Unified Command based on the size of 

the spill, weather and potential impacts. If aerial dispersants are utilized, 8 sorties (9,600 gallons) 

from two of the DC-3 aircrafts and 4 sorties (8,000 gallons) from the Basler aircraft would 
Page 2 of 18 

provide a daily dispersant capability of 7,540 barrels. If the conditions are favorable for in-situ 

burning, the proper approvals have been obtained and the proper planning is in place, in-situ 

burning of oil may be attempted. Slick containment boom would be immediately called out and 

on-scene as soon as possible. Offshore response strategies may include attempting to skim 

utilizing from CGA and MSRC, with a total derated skimming capacity of 286,244 barrels. 

Temporary storage associated with skimming equipment equals 207,202 barrels. If additional 

storage is needed, a 25,000 barrel storage barge, a 20,000 barrel storage barge, and two 23,000 

barrel storage barges may be mobilized and centrally located to provide temporary storage 

allowing the skimmers to stay in the area of operations as much as possible. Safety is first 

priority. Air monitoring will be accomplished and operations deemed safe prior to any 

containment/skimming attempts. 

If the spill went unabated, shoreline impact in Plaquemines Parish, Louisiana would depend 

upon existing environmental conditions. Shoreline protection would include the use of CGA’s 

near shore and shallow water skimmers with a totaled derated skimming capacity of 92,753 

barrels. Temporary storage associated with skimming equipment equals 1,198 barrels. If 

additional storage is needed, a 47,000 barrel storage barge, a 23,000 barrel storage barge, and 

two 20,000 barrel storage barges may be mobilized and centrally located to provide temporary 

storage allowing the skimmers to stay in the area of operations as much as possible. Onshore 

response may include the deployment of shoreline boom on beach areas, or protection and 

sorbent boom on vegetated areas. Master Service Agreements with AMPOL and OMI 

Environmental will ensure access to 147,000 feet of 18” shoreline protection boom. Figure 2

outlines individual times needed for procurement, load out, travel time to the site and 

deployment. Strategies would be based upon surveillance and real time trajectories that depict 

areas of potential impact given actual sea and weather conditions. The State of Louisiana Initial 

Oil Spill Response Plan for Plaquemines Parish and Unified Command would be consulted to 

ensure that environmental and special economic resources would be correctly identified and 

prioritized to ensure optimal protection. Shoreline protection strategies depict the protection 

response modes applicable for oil spill clean-up operations. The State of Louisiana Initial Oil 

Spill Response Plan provides detailed shoreline protection strategies for this area, and it 

describes necessary action to keep the oil spill from entering Louisiana’s coastal wetlands, based 

on the assumption that removal of the released oil will be much easier and less damaging to 

fragile coastal ecosystems if done in the open waters of the Gulf of Mexico. Supervisory 

personnel have the option to modify the deployment and operation of equipment allowing a more 

effective response to site-specific circumstances. Noble Energy, Inc.’s contract Spill 

Management Team holds a copy of the State of Louisiana Initial Oil Spill Response Plan. 

Based on the anticipated worst case discharge scenario, Noble Energy, Inc. can be onsite with 

contracted oil spill recovery equipment with adequate response capacity to contain and recover 

surface hydrocarbons, and prevent land impact, to the maximum extent practicable, within an 

estimated 62 hours (based on the equipment’s Effective Daily Recovery Capacity (EDRC)). 
Page 3 of 18 

Initial Response Considerations 

Actual actions taken during an oil spill response will be based on many factors which include but 

are not limited to: 

• Weather 

• Equipment and materials availability 

• Ocean currents and tides 

• Location of the spill 

• Product spilled 

• Amount spilled 

• Environmental risk assessments 

• Trajectory and product analysis 

• Well status, i.e., shut in or continual release 

Noble Energy, Inc. will take action to provide a safe, aggressive response to contain and recover 

as much of the spilled oil as quickly as it is safe to do so. In an effort to protect the environment, 

response actions will be designed to provide an “in-depth” protection strategy meant to recover 

as much oil as possible as far from environmentally sensitive areas as possible. Safety will take 

precedence over all other considerations during these operations. 

Coordination of response assets will be supervised by the designation of a SIMOPS group as 

necessary for close quarter vessel response activities. Most often, this group will be used during 

source control events that require a significant number of large vessels operating independently, 

but in coordination to complete a common objective, in a small area and in close coordination 

and support of each other. This group must also monitor the subsurface activities of each vessel 

(ROV, dispersant application, well control support, etc.). The SIMOPS group leader reports to 

the Source Control Section Chief. 

In addition, these activities will be monitored by the spill management team (SMT) and Unified 

Command via a structured Common Operating Picture (COP) established to track resource and 

slick movement in real time. 

Upon notification of a spill, the following actions will be taken: 

• Information will be confirmed 

• An assessment will be made and initial objectives set 

• OSROs and appropriate agencies will be notified 

• ICS 201, Initial Report Form will be completed 

• Initial Safety plan will be written and published 

• Unified Command will be established 

o Overall safety plan developed to reflect the operational situation and coordinated 

objectives 

o Areas of responsibility established for Source Control and each surface operational 

site 

o On-site command and control established 
Page 4 of 18 

Decanting Strategy 

Recovered oil and water mixtures will typically separate into distinct phases when left in a 

quiescent state. When separation occurs, the relatively clean water phase can be siphoned or 

decanted back to the recovery point with minimal, if any, impact. Decanting therefore increases 

the effective on-site oil storage capacity and equipment operating time. FOSC/SOSC approval 

will be requested prior to decanting operations. This practice is routinely used for oil spill 

recovery. 

Offshore Response Actions 

Equipment Deployment

Surveillance 

• Surveillance Aircraft will be deployed within two hours of Qualified Individual (QI) 

notification, or at first light

• Provide trained observer to provide on site status reports 

• Provide command and control platform at the site if needed 

• Continual surveillance of oil movement by remote sensing systems, aerial photography 

and visual confirmation 

• Continual monitoring of vessel assets using vessel monitoring systems 

Dispersant application assets 

• Put Airborne Support Inc. (ASI) on standby 

• With the Federal On-Scene Coordinator (FOSC), conduct analysis to determine 

appropriateness of dispersant application 

• Gain FOSC approval for use of dispersants on the surface 

• Deploy aircraft in accordance with a plan developed for the actual situation 

• Coordinate movement of dispersants, aircraft, and support equipment and personnel 

• Confirm dispersant availability for current and long range operations 

• Start ordering dispersant stocks required for expected operations 

Containment boom 

• Call out early and expedite deployment to be on scene ASAP 

• Ensure boom handling and mooring equipment is deployed with boom 

• Provide continuing reports to vessels to expedite their arrival at sites that will provide for 

their most effective containment 

• Use Vessels of Opportunity (VOO) to deploy and maintain boom 

Dedicated off-shore skimming systems 

General 

• Deployed to the highest concentration of oil 

• Assets deployed at safe distance from aerial dispersant and in-situ burn operations 
Page 5 of 18 

CGA HOSS Barge 

• Use in areas with heaviest oil concentrations 

• Consider for use in areas of known debris (seaweed, and other floating materials) 

CGA FRUs 

• To the area of the thickest oil 

• Use as far off-shore as allowed 

• VOOs 140’ – 180’ in length 

• VOOs with minimum of 18’ x 38’ or 23’ x 50’ of optimum deck space 

• VOOs in shallow water should have a draft of <10 feet when fully loaded 

MSRC Oil Spill Response Vessels (OSRV) 

• Use in areas with heaviest oil concentrations 

• Use as far off-shore as allowed 

MSRC Responders 

• Use in areas with heaviest oil concentrations 

• Consider for use in areas of known debris (seaweed, and other floating materials) 

Storage Vessels 

• Establish availability of CGA contracted assets 

• Early call out (to allow for tug boat acquisition and deployment speeds) 

• Phase mobilization to allow storage vessels to arrive at the same time as skimming 

systems 

• Position as closely as possible to skimming assets to minimize offloading time 

Vessels of Opportunity (VOO) 

• Use Noble Energy, Inc.’s contracted resources as applicable 

• Industry vessels are usually best for deployment of Vessel of Opportunity Skimming 

Systems (VOSS) 

• Acquire additional resources as needed 

• Consider use of local assets, i.e. fishing and pleasure craft 

• Expect mission specific and safety training to be required 

• Plan with the US Coast Guard for vessel inspections 
Page 6 of 18 

In-situ Burn assets 

• Determine appropriateness of in-situ burn operation in coordination with the FOSC and 

affected State On-Scene Coordinator (SOSC) 

• Determine availability of fire boom and selected ignition systems 

• Start ordering fire boom stocks required for expected operations 

• Contact boom manufacturer to provide training if required 

• Determine assets to perform on water operation 

• Build operations into safety plan 

• Conduct operations in accordance with an approved plan 

Adverse Weather Operations: 

In adverse weather, when seas are > 3 feet, the use of larger recovery and storage vessels, 

oleophilic skimmers, and large offshore boom will be maximized. Safety will be the overriding 

factor in all operations and will cease at the order of the Unified Command, vessel captain, or in 

an emergency, ”stop work” may be directed by any crew member. 
Page 7 of 18 

Near Shore Response Actions 

Timing 

• Place near shore assets on standby and deploy in accordance with planning based on the 

actual situation, actual trajectories and oil budgets 

• VOO identification and training in advance of spill nearing shoreline if possible 

• Outfitting of VOOs for specific missions 

• Deployment of assets based on actual movement of oil 

Considerations 

• Water depth, vessel draft 

• Shoreline gradient 

• State of the oil 

• Use of VOOs 

• Distance of surf zone from shoreline 

Equipment Deployment 

Surveillance 

• Provide trained observer to direct skimming operations 

• Continual surveillance of oil movement by remote sensing systems, aerial photography 

and visual confirmation 

• Continual monitoring of vessel assets 

Dispersant Use 

• Generally will not be approved within 3 miles of shore or with less than 10 meters of 

water depth 

• Approval would be at Regional Response Team level (Region 6) 

Vessel Deployment 

Dedicated Near Shore skimming systems 

• Fast Response Vessels (FRV) 

• Egmopol and Marco Shallow Water Skimmer (SWS) 

• Operate with aerial spotter directing systems to observed oil slicks 

VOO 

• Use Noble Energy, Inc.’s contracted resources as applicable 

• Industry vessels are usually best for deployment of Vessel of Opportunity Skimming 

Systems (VOSS) 

• Acquire additional resources as needed 

• Consider use of local assets, i.e. fishing and pleasure craft 

• Expect mission specific and safety training to be required 

• Plan with the US Coast Guard for vessel inspections 

• Operate with aerial spotter directing systems to oil patches 
Page 8 of 18 

Shoreline Protection Operations 

Response Planning Considerations 

• Environmental risk assessments (ERA) to determine priorities for area protection 

• Time to acquire personnel and equipment and their availability 

• Previous contingency planning contained in the appropriate Area Contingency Plan, and 

currently for Louisiana, The State of Louisiana Initial Oil Spill Response Plan, Deep 

Water Horizon, dated 2 May 2010 

Actions 

Placement of boom 

• Position boom in accordance with the ERA based on the actual situation or the 

appropriate ACP 

• Assess timing of booming operations to ensure it is where it needs to be at time of 

impact. Consider: 

o Trajectories 

o Weather forecast 

o Oil Impact forecast 

o Verified spill movement 

o Boom, manpower and vessel (shallow draft) availability 

o Near shore boom and support material, (stakes, anchors, line) 

Beach Preparation 

Considerations and Actions 

• Use of a 10 mile go/no go line to determine timing of beach cleaning 

• Shoreline Cleanup and Assessment Team Reports and recommendations 

• Determination of Archeological sites and gaining authority to enter 

• Monitoring of tide tables and weather to determine extent of high tides 

• Pre cleaning of beaches by moving waste above high tide lines to minimize waste 

• Staging of equipment and housing of response personnel as close to the job site as 

possible to maximize on-site work time 

• Boom tending, repair, replacement and security (use of local assets may be advantageous) 

• Constant awareness of weather and oil movement for resource redeployment as necessary 

• In-situ burn may be considered when marshes have been impacted 

• Passive clean up of marshes should be considered and appropriate stocks of sorbent boom 

and/or sweep obtained 

• Earthen berms and shoreline protection boom may be considered to protect sensitive 

inland areas 
Page 9 of 18 

Decanting Strategy 

Recovered oil and water mixtures will typically separate into distinct phases when left in a 

quiescent state. When separation occurs, the relatively clean water phase can be siphoned or 

decanted back to the recovery point with minimal, if any, impact. Decanting therefore increases 

the effective on-site oil storage capacity and equipment operating time. FOSC/SOSC approval 

will be requested prior to decanting operations. This practice is routinely used for oil spill 

recovery. 

CGA Equipment Limitations 

The capability for any spill response equipment, whether a dedicated or portable system, to 

operate in differing weather conditions will be directly in relation to the capabilities of the vessel 

the system in placed on. Most importantly, however, the decision to operate will be based on the 

judgment of the Unified Command and/or the Captain of the vessel, who will ultimately have the 

final say in terminating operations. Skimming equipment listed below may have operational 

limits which exceed those safety thresholds. As was seen in the Deepwater Horizon (DWH) oil 

spill response, vessel skimming operations ceased when seas reached 5-6 feet and vessels were 

often recalled to port when those conditions were exceeded. Systems below are some of the most 

up-to-date systems available and were employed during the DWH spill. 

Boom 3 foot seas, 20 knot winds 

Dispersants Winds more than 25 knots 

Visibility less than 3 nautical miles 

Ceiling less than 1,000 feet. 

FRU 8 foot seas 

HOSS Barge/OSRB 8 foot seas 

Koseq Arms 8 foot seas 

OSRV 4 foot seas 
Page 10 of 18 

Environmental Conditions in the GOM

Louisiana is situated between the easterly and westerly wind belts, and therefore, experiences 

westerly winds during the winter and easterly winds in the summer. Average wind speed is 

generally 14-15 mph along the coast. Wave heights average 4 and 5 feet. However, during 

hurricane season, Louisiana has recorded wave heights ranging from 40 to 50 feet high and 

winds reaching speeds of 100 mph. Because much of southern Louisiana lies below sea level, 

flooding is prominent. 

Surface water temperature ranges between 70 and 80 ̊F during the summer months. During the 

winter, the average temperature will range from 50 and 60 ̊F. 

The Atlantic and Gulf of Mexico hurricane season is officially from 1 June to 30 November. 

97% of all tropical activity occurs within this window. The Atlantic basin shows a very peaked 

season from August through October, with 78% of the tropical storm days, 87% of the minor 

(Saffir-Simpson Scale categories 1 and 2) hurricane days, and 96% of the major (Saffir-Simpson 

categories 3, 4 and 5) hurricane days occurring then. Maximum activity is in early to mid 

September. Once in a few years there may be a hurricane occurring "out of season" - primarily in 

May or December. Globally, September is the most active month and May is the least active 

month. 
Page 11 of 18 

FIGURE 1 

TRAJECTORY BY LAND SEGMENT 

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

utilizing Noble Energy, Inc.’s WCD and information in the BSEE Oil Spill Risk Analysis 

Model (OSRAM) for the Central and Western Gulf of Mexico available on the BSEE 

website using 30 day impact. The results are tabulated below. 

Area/Block OCS-G Launch 

Area 

Land Segment and/or 

Resource 

Conditional 

Probability (%) 

within 30 days 

Exploratory Drilling 

MC 782, 

Well Location A 

74 miles from shore 

G33757 C59 Cameron, LA 

Vermilion, LA 

Terrebonne, LA 

Lafourche, LA 

Jefferson, LA 

Plaquemines, LA 

St. Bernard, LA 

Walton, FL 

Bay, FL 

1 

1 

2 

2 

1 

11 

2 

1 

1 
Page 12 of 18 

WCD Scenario– BASED ON WELL BLOWOUT DURING DRILLING OPERATIONS (74 miles from sh

138,571 bbls of crude oil (Volume considering natural weathering) API Gravity 26.3° 

FIGURE 2 – Equipment Response Time to MC 782, Well Location A 

Dispersants/Surveillance 

Dispersant/Surveillance Dispersant Capacity (gal) Storage Capacity Persons Req. From Hrs to Procure Hrs to Loadout Travel to site 

CGA 

Basler 67T 2000 NA 2 Houma 1 1 0.9 

ASI 

DC 3 1200 NA 2 Houma 1 1 1.1 DC 3 1200 NA 2 Houma 1 1 1.1 Aero Commander NA NA 2 Houma 1 1 0.9 

Offshore Response 

Offshore Equipment EDRC Storage Capacity VOO Persons Required From Hrs to Procure Hrs to Loadout Hrs to GOM 

CGA 

HOSS Barge 43000 4000 3 Tugs 8 Harvey 7 0 5 

Enterprise Marine Services LLC (available through contract with CGA) 

CTCo 2603 NA 25000 1 Tug 6 Amelia 4 12 4 CTCo 2606 NA 20000 1 Tug 6 Amelia 4 12 4 CTCo 2607 NA 23000 1 Tug 6 Amelia 4 12 4 CTCo 2608 NA 23000 1 Tug 6 Amelia 4 12 4 
Page 13 of 18 

Offshore Equipment 

Pre-determined Staging EDRC Storage Capacity VOO Persons Required From Hrs to Procure Hrs to Loadout Hrs to GOM 

MSRC 

Louisiana Responder LFF 100 Brush + OSRV 2,640’ 44” Sea Sentry II Boom 5,280’ 67” LAMOR 

18086 4000 NA 14 Fort Jackson 2 0 1 

MSRC 452 Offshore Barge 1 Crucial Disk 88/30 1,980’ 44” Sea Sentry II Boom 660 ‘ 67” LAMOR 

11122 45000 3 Tugs 6 Fort Jackson 2 0 2 

Mississippi Responder Transrec 350 + OSRV 5,280’ 44” Sea Sentry II Boom 2,640’ 67” LAMOR 

10567 4000 NA 14 Pascagoula 2 0 1 

MSRC 402 Offshore Barge 2 Crucial Disk 88/30 660’ 44” Sea Sentry II Boom 1,980‘ 67” LAMOR 

22244 40300 3 Tugs 6 Pascagoula 2 0 2 

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

18086 4000 NA 14 Fourchon 2 0 1 

PSV – HOS Centerline 1 Crucial Disk 88/30 1,320’ EFC (cont inflate) 

11122 10626 NA 14 Fourchon 12 12 1 

PSV – HOS Strongline 1 Crucial Disk 88/30 1,320’ EFC (cont inflate) 

11122 10626 NA 14 Fourchon 12 12 1 

PSV – C-Freedom 1 LFF 100 Brush 1,320’ EFC (cont inflate) 

18086 6000 NA 14 Fourchon 12 12 1 

PSV – C-Leader 1 LFF 100 Brush 1,320’ EFC (cont inflate) 

18086 6000 NA 14 Fourchon 12 12 1 

PSV – Allysa Chouest 1 LFF 100 Brush 1,320’ EFC (cont inflate) 

18086 6000 NA 14 Fourchon 12 12 1 
Page 14 of 18 

Offshore Equipment 

Pre-determined Staging EDRC Storage Capacity VOO Persons Required From Hrs to Procure Hrs to Loadout Hrs to GOM 

MSRC 

MSRC Lightning 2 LORI Brush Pack 5000 50 3 Tugs 6 Tampa 2 0 2 Gulf Coast Responder Transrec 350 + OSRV 5,280’ 44” Sea Sentry II Boom 2,640’ 67” LAMOR 

10567 4000 NA 14 Lake Charles 2 0 1 

Texas Responder Transrec 350 + OSRV 4,620’ 44” Sea Sentry II Boom 3,300’ 67” LAMOR 

10567 4000 NA 14 Galveston 2 0 1 

MSRC 570 Offshore Barge 2 Crucial Disk 88/30 2,640’ 44” Sea Sentry II Boom 

22244 56900 3 Tugs 6 Galveston 2 0 2 
Page 15 of 18 

Staging Area: Venice

Offshore Equipment With 

Staging EDRC Storage Capacity VOO Persons Req. From Hrs to Procure Hrs to Loadout Travel to Staging 

CGA 

FRU (1) + 100 bbl Tank (2) 4251 200 1 Utility 6 Morgan City 1 2 3 FRU (1) + 100 bbl Tank (2) 4251 200 1 Utility 6 Galveston 1 2 8 FRU (2) + 100 bbl Tank (4) 8502 400 2 Utility 12 Leeville 1 2 3.5 FRU (1) + 100 bbl Tank (1) 4251 100 1 Utility 6 Harvey 1 2 1.5 FRU (1) + 100 bbl Tank (2) 4251 200 1 Utility 6 Ingleside 1 2 11 FRU (1) + 100 bbl Tank (2) 4251 200 1 Utility 6 Lake Charles 1 2 5.5 FRU (2) + 100 bbl Tank (4) 8502 400 2 Utility 12 Venice 1 2 0 42” Auto Boom (5000’) NA NA 10 Crew 20 Galveston 1 2 8 42” Auto Boom (10000’) NA NA 20 Crew 40 Harvey 1 2 1.5 42” Auto Boom (2500’) NA NA 6 Crew 12 Ingleside 1 2 11 42” Auto Boom (5000’) NA NA 10 Crew 20 Lake Charles 1 2 5.5 42” Auto Boom (2500’) NA NA 6 Crew 12 Pascagoula 1 2 4 1000’ Hydro-Fire Boom NA NA 8 Utility 40 Harvey 1 4 1.5 

MSRC 

44” Sea Sentry II Boom (2860’) NA NA 6 Crew 12 Ingleside 1 2 11 44” Sea Sentry II Boom (4290’) NA NA 10 Crew 20 Galveston 1 2 8 44” Sea Sentry II Boom (6679’) NA NA 10 Crew 20 Lake Charles 1 2 5.5 44” Sea Sentry II Boom (1980’) NA NA 6 Crew 12 Fort Jackson 1 2 .5 44” Sea Sentry II Boom (3190’) NA NA 10 Crew 20 Pascagoula 1 2 4 2000’ Hydro-Fire Boom NA NA 16 Utility 80 Lake Charles 1 4 5.5 
Page 16 of 18 

Nearshore Response 

Nearshore Equipment 

Pre-determined Staging EDRC Storage Capacity VOO Persons Required From Hrs to Procure Hrs to Loadout Hrs to GOM 

CGA 

Trinity SWS 21500 249 NA 4 Morgan City 1 2 2 Trinity SWS 21500 249 NA 4 Leeville 1 2 2 Trinity SWS 21500 249 NA 4 Venice 1 2 2 46’ FRV 5000 65 NA 4 Leeville 1 0 2 46’ FRV 5000 65 NA 4 Lake Charles 1 0 1 46’ FRV 5000 65 NA 4 Venice 1 0 1 

Enterprise Marine Services LLC (Available through contract with CGA) 

CTCo 2604 NA 20000 1 Tug 6 Amelia 4 12 4 CTCo 2605 NA 20000 1 Tug 6 Amelia 4 12 4 CTCo 2609 NA 23000 1 Tug 6 Amelia 4 12 4 CTCo 5001 NA 47000 1 Tug 6 Amelia 4 12 4 

Staging Area: Venice 

Nearshore and Inland 

Skimmers With Staging EDRC Storage Capacity VOO Persons Req. From Hrs to Procure Hrs to Loadout Travel to Staging T

De

CGA 

SWS Egmopol 3000 100 NA 3 Galveston 1 2 8 SWS Egmopol 3000 100 NA 3 Houma 1 2 3 SWS Marco 3588 34 NA 3 Houma 1 2 3 SWS Marco 3588 20 NA 3 Lake Charles 1 2 5.5 Rope Mop 77 2 0 3 Belle Chasse 1 2 2 
Page 17 of 18 

Shoreline Protection 

Staging Area: Venice 

18” Shoreline 

Protection Boom VOO Persons Req. Storage/Warehouse Location Hrs to Procure Hrs to Loadout Travel to Staging Travel to Deployment 

AMPOL (available through MSA) 

42,000’ 18” Boom 16 Crew 40 New Iberia, LA 2 2 4 2 20,000’ 18” Boom 8 Crew 20 New Orleans, LA 2 2 2 2 

OMI Environmental (available through MSA) 

10,000’ 18” Boom 4 Crew 10 New Iberia, LA 1 1 4 2 10,000’ 18” Boom 4 Crew 10 Houston, TX 1 1 7.5 2 10,000’ 18” Boom 4 Crew 10 Port Arthur, TX 1 1 6.25 2 20,000’ 18” Boom 8 Crew 20 Belle Chasse, LA 1 1 1.75 2 10,000’ 18” Boom 4 Crew 10 Port Allen, LA 1 1 3.5 2 10,000’ 18” Boom 4 Crew 10 Houma, LA 1 1 3.5 2 15,000’ 18” Boom 6 Crew 14 Gretna, LA (Warehouse) 2 2 2 2 

Beach Boom EDRC Storage Capacity VOO Persons Req. From Hrs to Procure Hrs to Loadout Travel to Staging T

De

CGA 

Beach Boom (2000’) NA NA NA 6 Galveston 1 2 8 Beach Boom (1000’) NA NA NA 4 Ingleside 1 2 11 Beach Boom (2000’) NA NA NA 6 Pascagoula 1 2 4 
Page 18 of 18 

Staging Area: Venice 

Wildlife Response EDRC Storage Capacity VOO Persons Req. From Hrs to Procure Hrs to Loadout Travel to Staging T

De

CGA 

Wildlife Support Trailer NA NA NA 2 Houma 1 2 3 Bird Scare Guns (24) NA NA NA 2 Belle Chasse 1 2 2 Bird Scare Guns (12) NA NA NA 2 Galveston 1 2 8 Bird Scare Guns (24) NA NA NA 2 Houma 1 2 3 Bird Scare Guns (12) NA NA NA 2 Ingleside 1 2 11 Bird Scare Guns (24) NA NA NA 2 Lake Charles 1 2 5.5 Bird Scare Guns (24) NA NA NA 2 Pascagoula 1 2 4 

Response Asset Total 

Offshore EDRC 286,244 Offshore Recovered Oil Storage 298,202 Nearshore / Shallow Water EDRC 92,753 Nearshore / Shallow Water Recovered Oil Storage 111,198 
Section I

Environmental Monitoring and Mitigation Information

A. Monitoring Systems

There are no environmental monitoring systems currently in place or planned for the proposed activities.

B. Incidental Takes

There is no reason to believe that protected species may be incidentally taken by the activities proposed

in this Initial Exploration Plan. However, Noble will comply with Joint NTL No. 2012-G01 “Vessel

Strike Avoidance and Injured/Dead Protected Species Reporting” BSEE No. 2012-G01 “Marine Trash

and Debris Awareness and Elimination”.

C. Flower Garden Banks National Marine Sanctuary

Mississippi Canyon 738 and 782 are not located in the Flower Garden Banks National Marine Sanctuary;

therefore, the requested information is not required in this EP.

Noble Energy, Inc. Page I-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Section J

Lease Stipulations Information

Exploration activities are subject to the following stipulations attached to Lease OCS-G 333755 &

33757, Mississippi Canyon 738 & 782.

Marine Protected Species

Lease Stipulation No. 8 is meant to reduce the potential taking of marine protected species. Noble will

operate in accordance with NTL 2003-G10 which has been superseded by NTL 2007-G04 and Joint NTL

2012-G01, to minimize the risk of vessel strikes to protected species and report observations of injured or

dead protected species, and NTL 2003-G11 which has been superseded by NTL 2007-G03 and BSEE

NTL 2012-G01 to prevent intentional and/or accidental introduction of debris into the marine

environment.

Noble Energy, Inc. Page J-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Section K

Support Vessels and Aircraft Information

A. General

The most practical, direct route from the shorebase as permitted by weather and traffic conditions will

be utilized.

Type Maximum Fuel

Tank Capacity

Maximum

Number in Area

at Any Time

Trip Frequency

or Duration

Supply Boat 9,588 bbls 2 2 trips per week

Supply Boat 7,082 bbls 1 4 trips per week

Crew Boat 809 bbls 1 4 trips per week

Helicopter S-92 764 gals 1 4 trips per week

B. Diesel Oil Supply Vessels

Size of Fuel Supply

Vessel

Capacity of Fuel

Supply Vessel

Frequency of Fuel

Transfers

Route Fuel Supply

Vessel Will Take

Norbert Bouziga - 280 Feet 310,000 gals Once a month From the shore base

in Fourchon, LA to

MC 738 & 782 Field

then to Fourchon , LA

Gary Chouest - 276 Feet 300,000 gals Once every 3

months

From the shore base in

Fourchon, LA to MC

738 & 782 Field then

to Fourchon , LA

C. Solid and Liquid Wastes Transportation

See section F, Waste and Discharge Information and Section L, Onshore Support Facilities Information,

Waste Disposal.

D. Vicinity Map

Enclosed as Attachment K-1 is a vicinity map showing the location of the activities proposed herein

relative to the shoreline with the distance of the proposed activities from the shoreline and the primary

route(s) of the support vessels and aircraft that will be used when traveling between the onshore support

facilities and the drilling unit.

Noble Energy, Inc. Page K-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Distance from

Dantzier to

Fourchon

(roughly)

210 km

130 mi

113 nmi

Distance from

Dantzier to shore

(roughly)

118 km

74 mi

64 nmi

VENICE

CAMERON

FOURCHON

GRAND ISLE

FRESHWATER CITY

INTRACOASTAL CITY

MC 738/782

LOUISIANA

TEXAS

DEEP WATER

BUSINESS UNIT

MISSISSIPPI CANYON 738/782

LOUISIANA

VICINITY PLAT

GEOL./GEOP.: Staff C.I.:

FILENAME: DATE: 1/2013

Public

Information
Section L

Onshore Support Facilities Information

A. General

Provide a listing in the table below of the onshore facilities that will be used to provide supply and

service support for the proposed activities:

Name of Shorebase Location Existing/New/Modified

C Port 1 Slip 4 Port Fourchon, LA Existing

PHI Heliport Houma, LA Existing

B. Support Base Construction or Expansion

There will be no new construction of an onshore support base, nor will we expand the existing shore

base as a result of the operations proposed in this Exploration Plan.

Noble Energy, Inc. Page L-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
C. Waste Disposal

Provide information in the table below on the onshore facilities you will use to store and dispose of any

solid and liquid wastes generated by the proposed activities.

Type of Waste Composition

Solid and Liquid

Wastes Transport

Method

Name/Location

of Facility Amount Disposal Method

Will drilling occur ? If yes, fill in the muds and cuttings.

EXAMPLE: Synthetic-based

drilling fluid or mud internal olefin, ester

Below deck storage

tanks on offshore

support vessels

Newport

Environmental

Services Inc.,

Ingleside, TX X bbl/well Recycled

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

Synthetic-based drilling fluid or

mud Internal Olefin 25 bbl transport

US Fluids

Port Fourchon 273 bbls Injection

Synthetic-based drilling fluid or

mud Internal Olefin Boat tank

Baroid

Port Fourchon,

LA 10,938 bbls Reclamation

Cuttings wetted with Water-based

fluid

Cuttings generated

while using water based

drilling fluid. Seafloor N/A N/A N/A

Cuttings wetted with Syntheticbased fluid

Interfaces, cement

contamination Cutting boxes

Newpark

Environmental

Fourchon, LA 309 bbls Injection

Cuttings wetted with oil-based

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

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

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

Will you have additional wastes that are not permitted for discharge? If yes, fill in

the appropriate rows.

Lbs/

month

Recyclables

Plastic, paper,

aluminum

Approved

Compactor Bags

Tech Oil, New

Iberia, LA 2,500 lbs Recycled

Trash and debris Household Debris

Approved

Compactor Bags

C Port 1

Fourchon, LA 300,000 lbs Landfill/Disposal

Used oil 40 wt, 90 wt & hyd

DOT approved tote

tank

American

Recovery

Houma, LA 11,050 gals Recycled

Scrap Irons

Iron, Copper, Brass &

Stainless

4’ x 8’ Solid Bin

Basket

C Port Chouest

Offshore

Fourchon, LA 60,000 lbs Recycled

Chemical product wastes

Paint, Oily Rags, Gloves

& Tyvek Suits DOT approved drum

American

Recovery

Houma, LA 11,250 lbs

Processed,

Recycled/Disposed

Spent, dirty completion fluid Calcium Bromide

Offshore Support

Vessels

Newpark

Environmental

Fourchon, LA 2,000 bbls Injection

Completion fluid filtration media

& wash water

Diatomaceous Earth

and Water

25-bbl Cuttings

Boxes

Newpark

Environmental

Fourchon, LA 800 bbls Injection

Noble Energy, Inc. Page L-2

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Section M

Coastal Zone Management Act (CZMA) Information

Relevant enforceable policies were considered in certifying consistency for Louisiana. A certificate of

Coastal Zone Management Consistency for the state of Louisiana is enclosed as Attachment M-1.

Noble Energy, Inc. Page M-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)

Noble Energy, Inc. Page M-2

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)

For Alabama:

Alabama Coastal Zone Management

Consistency Certification

Initial Exploration Plan

Mississippi Canyon Block 738 & 782

OCS-G 33755 & 33757

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 to the

Initial Exploration Plan

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 petroleum exploration operations will take

place approximately 135 miles offshore of the Alabama

State Waters boundary in Federal waters.

Commercial

Fishing

Sections H – Oil Spill

Response Planning, &

Section N – Environmental

Impact Analysis

(C.8.1 Recreational and

Commercial Fishing)

There will be little or no impact on commercial fishing

under normal operations. A worst case discharge (WCD)

could result in fishery closures depending of the duration

of the discharge, meteorological conditions at the time,

and the effectiveness of spill response measures.

Hazard

Management

Section C – Geological and

Geophysical Information

A Shallow Hazards Assessment, Benthic Communities

Evaluation, and Archeological Resource Survey has been

submitted to BOEM in order to identify and assess the

seafloor and shallow geologic conditions in this block.

No significant geological hazards or archeological

resources are reported.

Shoreline Erosion Proposed petroleum exploration operations will take

place approximately 135 miles from Alabama’s coastal

waters and 138 miles from the actual Alabama coastline.

Dock and port facilities will be located in LA and vessels

will follow the shortest direct route to the project area.

There will be no new construction, dredging, or filling in

Alabama state waters and this project will have no
Noble Energy, Inc. Page M-3

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)

Topic Cross Reference to the

Initial Exploration Plan

Comments

impact on Alabama coastal erosion

Recreation Section N – Environmental

Impact Analysis

(C.8.4 Recreation and

Tourism)

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 the new BSEE

2012-G01 NTL will minimize the chance of trash or

debris being lost overboard from the drilling rig and

subsequently washing up on beaches.

Based on the revised 120 day OSRA modeling

(BOEMRE, 2011; and BOEM, 2012 as summarized in

attachment H-1 Oil Spill Response Discussion, there is a

1% or less chance that oil from a spill in this lease area

would reach shorelines in Baldwin Co., Alabama within

30 days..

Transportation Section N – Environmental

Impact Analysis

(C.8.6 Other Marine Uses)

The lease area is not located within any

USCG-designated fairway or shipping lane and there are

no impacts to Alabama transportations routes or

infrastructure.

Natural Resource Protection Policies

Biological

Productivity

Sections E – Waste

Discharge Information, and

Section N – Environmental

Impact Analysis

(C.1.2 Water Quality)

There will be no impacts to the coastal waters or

shorelines of Alabama under normal operations during

this project.

A worst case discharge (WCD) could result in temporary

losses in water column productivity within the offshore

and nearshore waters of Alabama depending of the

duration of the discharge, meteorological conditions at

the time, and the effectiveness of spill response

measures.

Based on the revised 120 day OSRA modeling

(BOEMRE, 2011, and BOEM 2012) as summarized in

attachment H-1 Oil Spill Response Discussion, there is a

1% or less chance that oil from a spill in this lease area

would reach shorelines in Baldwin Co., within 30 days.
Noble Energy, Inc. Page M-4

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)

Topic Cross Reference to the

Initial Exploration Plan

Comments

Water Quality Section N – Environmental

Impact Analysis

(C.1.2 Water Quality)

There would be no impacts to water quality within

Alabama coastal waters under normal operating

conditions during this project.

The impact producing factors (IPFs) potentially affecting

water quality are effluent discharges and two types of

accidents: a small diesel fuel spill and a large oil spill

(WCD).

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 during exploratory drilling.

Treated sanitary and domestic wastes may have a slight

transient effect on water quality in the immediate vicinity

of these discharges. All NPDES permit limitations and

requirements will be met, therefore, little or no impact on

water quality is anticipated.

A small diesel 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. 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 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.

Due to the lease area location (138 miles from the

Alabama shoreline), it is expected that most water quality
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Topic Cross Reference to the

Initial Exploration Plan

Comments

impacts would occur in offshore waters, especially in the

event of a spill lasting less than 30 days. Based on the

revised 120 day OSRA modeling (BOEMRE, 2011, and

BOEM 2012) as summarized in attachment H-1 Oil Spill

Response Discussion, there is a 1% or less chance that oil

from a spill in this lease area would reach shorelines in

Baldwin Co., within 30 days.

Water Resources Proposed petroleum exploration operations will take

place approximately 135 miles from Alabama’s coastal

waters and 138 miles from the actual Alabama coastline.

Dock and port facilities will be located in LA and all

supplies including fresh water will be purchased there.

There will be no new construction, dredging, or filling in

Alabama state waters and this project will have no

impact on Alabama coastal water resources.

Air Quality Section G – Air Emissions

Information, and Section N

– Environmental Impact

Analysis

(C.1.1 Air Quality)

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.

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

Wetlands and

Submerged

Grassbeds

Section A – Plan Contents,

and

Section N – Environmental

Impact Analysis

(C.7 Coastal Habitats and

Protected Areas)

There will be no estuarine, fresh water, or near shore

operations associated with this project and there will be

no impacts to Alabama wetlands or submerged grass

beds under normal operations.

Based on the revised 120 day OSRA modeling

(BOEMRE, 2011, and BOEM 2012) as summarized in

attachment H-1 Oil Spill Response Discussion, there is a

1% or less chance that oil from a spill in this lease area

would reach shorelines in Baldwin Co., within 30 days.

Beach and Dune

Protection

Section H – Oil Spill

Information, and Section N

– Environmental Impact

Analysis (C.7 Coastal

Habitats and Protected

There would be no impacts to Alabama beaches and

dunes under normal operations.

In the event of a major oil spill (WCD) the initial

response would be staged out of existing facilities, with
Noble Energy, Inc. Page M-6

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Topic Cross Reference to the

Initial Exploration Plan

Comments

Areas) no effect on Alabama land use. A large spill could have

limited temporary impacts on Alabama coastal lands if

additional staging areas were needed. These areas would

eventually return to their original state after the response

is demobilized.

Wildlife Habitat

Protection

Section E - Biological,

Physical, and

Socioeconomic

Information; Section H –

Oil Spill Information; and

Section N – Environmental

Impact Analysis

(C.7 Coastal Habitats and

Protected Areas)

Due to the distance from shore, there are no IPFs

associated with routine activities that are likely to affect

beaches and dunes, wetlands, seagrass beds, coastal

wildlife refuges, wilderness areas, or any other managed

or protected coastal area.

Potential spill impacts on coastal habitats from a large oil

spill (WCD) are discussed in recent EISs (MMS, 2007b,

2008, BOEMRE 2011, and BOEM 2012). 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.

Based on the revised 120 day OSRA modeling

(BOEMRE, 2011, and BOEM 2012) as summarized in

attachment H-1 Oil Spill Response Discussion, there is a

1% or less chance that oil from a spill in this lease area

would reach shorelines in Baldwin Co., within 30 days.

Endangered Species Section H – Oil Spill

Information, Section I –

Environmental Monitoring

Information, and, Section

N – Environmental Impact

Analysis (C.3 Threatened,

Endangered, and Protected

Species and Critical

Habitat)

As mandated by the ESA, BOEM consulted with NMFS

and FWS on possible and potential impacts from the

proposed leasing in the Central Gulf of Mexico Planning

Area 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, 2007b). The Biological Opinion

concludes that the proposed lease sales and associated

activities in the Gulf of Mexico in the current 5-Year

Program are not likely to jeopardize the continued

existence of threatened and endangered species under

NMFS jurisdiction or destroy or adversely modify

designated critical habitat.

Following the Macondo oil spill the BOEMRE requested

reinitiating of ESA consultation with both NMFS and

FWS on 30 July 2010. The NMFS responded with a
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Topic Cross Reference to the

Initial Exploration Plan

Comments

letter to BOEMRE on 24 September 2010. The FWS

responded with a letter to BOEMRE on

27 September 2010. The reinitiated consultations are not

complete at this time, although BOEM is in discussions

with both agencies. The existing consultations remain in

effect until the reinitiated consultations are completed

(BOEMRE, 2012).

Cultural Resources

Protection

Section E – H.

Archaeological Report and

Section N – Environmental

Impact Analysis

(C.6 Archaeological

Resources)

Mississippi Canyon Blocks 738 & 782 are on the list of

Lease Blocks with high potential for containing

archaeological properties (shipwrecks). Beginning in

2011 archeological scurvies are now required prior to

any new construction before a permit will be issued by

BOEM.

A site clearance letter report is submitted under separate

cover in the Initial Exploration Plan. No evidence of

shipwrecks or other potential archeological resources

was found in Mississippi Canyon Blocks 738 & 782.

An oil spill entering shallow coastal waters of Alabama

could conceivably contaminate an archaeological and

cultural resources along the shoreline. Based on the

revised 120 day OSRA modeling (BOEMRE, 2011, and

BOEM 2012) as summarized in attachment H-1 Oil Spill

Response Discussion, there is a 1% or less chance that oil

from a spill in this lease area would reach shorelines in

Baldwin Co., within 30 days.

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

A certificate of Coastal Management Consistency for the State of Alabama is enclosed as

Attachment M-2.

Section N

Environmental Impact Analysis (EIA)

See attachment N – 1.

Noble Energy, Inc. Page N-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)
Environmental Impact Analysis

INITIAL EXPLORATION PLAN

for

Mississippi Canyon Block 738 (OCS-G 33755) and

Mississippi Canyon Block 782 (OCS-G 33757)

Offshore Alabama

March 2013

Prepared for:

Noble Energy, Inc.

100 Glenborough Drive, Suite 100

Houston, Texas 77067

Telephone: (381) 872-3100

Prepared by:

CSA Ocean Sciences Inc.

8502 SW Kansas Avenue

Stuart, Florida 34997

Telephone: (772) 219-3000
Mississippi Canyon Blocks 738 and 782 March 2013

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.......................................................................................... 5

A.3 Air Pollutant Emissions .............................................................................................................. 8

A.4 Effluent Discharges.................................................................................................................... 8

A.5 Water Intake ............................................................................................................................. 8

A.6 Onshore Waste Disposal............................................................................................................ 8

A.7 Marine Debris............................................................................................................................ 9

A.8 Support Vessel and Helicopter Traffic ........................................................................................ 9

A.9 Accidents................................................................................................................................... 9

A.9.1 Types of Accidents Evaluated ......................................................................................... 9

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...........................................................................................16

C. Impact Analysis.....................................................................................................18

C.1 Physical/Chemical Environment............................................................................................... 18

C.1.1 Air Quality .................................................................................................................... 18

C.1.2 Water Quality............................................................................................................... 20

C.2 Seafloor Habitats and Biota ..................................................................................................... 22

C.2.1 Soft Bottom Benthic Communities................................................................................ 22

C.2.2 High-Density Deepwater Benthic Communities ............................................................ 25

C.2.3 Designated Topographic Features................................................................................. 27

C.2.4 Pinnacle Trend Area Live Bottoms ................................................................................ 27

C.2.5 Eastern Gulf Live Bottoms ............................................................................................ 28

C.3 Threatened, Endangered, and Protected Species and Critical Habitat ...................................... 28

C.3.1 Sperm Whale (Endangered).......................................................................................... 30

C.3.2 West Indian Manatee (Endangered) ............................................................................. 34

C.3.3 Endangered Mysticete Whales ..................................................................................... 36

C.3.4 Non-Endangered Marine Mammals (Protected) ........................................................... 36

C.3.5 Sea Turtles (Endangered/Threatened) .......................................................................... 39

C.3.6 Piping Plover (Threatened) ........................................................................................... 42

C.3.7 Whooping Crane (Endangered)..................................................................................... 45

C.3.8 Gulf Sturgeon (Threatened).......................................................................................... 45

C.3.9 Smalltooth Sawfish (Endangered)................................................................................. 46

C.3.10 Beach Mice (Endangered)............................................................................................. 47

C.3.11 Elkhorn Coral (Endangered).......................................................................................... 47
Contents

(Continued)

Page

Mississippi Canyon Blocks 738 and 782 March 2013

Environmental Impact Analysis for Initial Exploration Plan Page iii

C.4 Coastal and Marine Birds......................................................................................................... 48

C.4.1 Marine Birds................................................................................................................. 48

C.4.2 Shorebirds and Coastal Nesting Birds............................................................................ 50

C.5 Fisheries Resources ................................................................................................................. 53

C.5.1 Pelagic Communities and Ichthyoplankton ................................................................... 53

C.5.2 Essential Fish Habitat.................................................................................................... 55

C.6 Archaeological Resources ........................................................................................................ 58

C.6.1 Shipwreck Sites ............................................................................................................ 58

C.6.2 Prehistoric Archaeological Sites .................................................................................... 59

C.7 Coastal Habitats and Protected Areas ...................................................................................... 60

C.8 Socioeconomic and Other Resources ....................................................................................... 63

C.8.1 Recreational and Commercial Fishing ........................................................................... 63

C.8.2 Public Health and Safety............................................................................................... 64

C.8.3 Employment and Infrastructure.................................................................................... 65

C.8.4 Recreation and Tourism ............................................................................................... 66

C.8.5 Land Use ...................................................................................................................... 67

C.8.6 Other Marine Uses ....................................................................................................... 68

D. Environmental Hazards.........................................................................................68

D.1 Geologic Hazards ..................................................................................................................... 68

D.2 Severe Weather....................................................................................................................... 68

D.3 Currents and Waves ................................................................................................................ 68

E. Alternatives ..........................................................................................................69

F. Mitigation Measures .............................................................................................69

G. Consultation .........................................................................................................69

H. Preparers..............................................................................................................69

I. References .............................................................................................................70
Mississippi Canyon Blocks 738 and 782 March 2013

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: BOEM, 2012b, Appendix C)..................................................................... 12

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 (Adapted from: Wei, 2006; Rowe and Kennicutt, 2009) .......... 23

5 Federally listed endangered and threatened species potentially occurring in the

lease area and along the northern Gulf Coast................................................................... 29

6 Wildlife refuges, wilderness areas, and State and National parks within the

geographic range of the potential shoreline contacts after 120 days (From: BOEM,

2012b) ............................................................................................................................. 61

List of Figures

Figure Page

1 Location of Mississippi Canyon Blocks 738 and 782 ............................................................ 2

2 Bathymetric map of the lease area showing the surface hole locations of Wells A

and B in Mississippi Canyon Block 738 and A, B, C, and D in Mississippi Canyon

Block 782 ......................................................................................................................... 17

3 Location of selected environmental features in relation to the lease area ........................ 44
Mississippi Canyon Blocks 738 and 782 March 2013

Environmental Impact Analysis for Initial Exploration Plan Page v

Acronyms and Abbreviations

ADIOS2 Automated Data Inquiry for Oil Spills 2

bbl barrel

BOEM Bureau of Ocean Energy Management

BOEMRE Bureau of Ocean Energy Management,

Regulation and Enforcement

BOP blowout preventer

B.P. Before Present

BSEE Bureau of Safety and Environmental

Enforcement

CFR Code of Federal Regulations

CH4 methane

CO carbon monoxide

CO2 carbon dioxide

CGA Clean Gulf Associates

DP dynamic positioning

EEZ Exclusive Economic Zone

EFH Essential Fish Habitat

EIA Environmental Impact Analysis

EIS Environmental Impact Statement

EP Exploration Plan

ESA Endangered Species Act

FAD fish-attracting device

FR Federal Register

Fugro Fugro Geoconsulting, Inc.

GMFMC Gulf of Mexico Fishery Management

Council

GPS global positioning system

H2S hydrogen sulfide

HAPC Habitat Area of Particular Concern

HOSS high-volume open sea skimmer

IPF impact-producing factor

MARPOL International Convention for the

Prevention of Pollution from Ships

MC Mississippi Canyon

MMC Marine Mammal Commission

MMPA Marine Mammal Protection Act

MMS Minerals Management Service

MSRC Marine Spill Response Corporation

NAAQS National Ambient Air Quality

Standards

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric

Administration

NO2 nitrogen dioxide

NOx nitrogen oxides

Noble Noble Energy, Inc.

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
Mississippi Canyon Blocks 738 and 782 March 2013

Environmental Impact Analysis for Initial Exploration Plan Page 1

Introduction

Noble Energy, Inc. (Noble) is submitting an Initial Exploration Plan (EP) for Mississippi Canyon

(MC) Blocks 738 and 782 (MC 738 and 782). The EP includes six exploratory well locations: A, B

and D in MC 738 and A, B, and C, in MC 782. The surface hole locations (SHLs) for the six wells

will be located in the respective blocks, MC 738 or MC 782. This Environmental Impact Analysis

(EIA) provides information on the exploratory wells based on the SHLs.

The lease area is 74 miles (119 km) southeast of the nearest shoreline, 131 miles (211 km) from

the onshore support base at Port Fourchon, Louisiana, and 173 miles (279 km) from the

helicopter base at Houma, Louisiana (Figure 1). Water depths at the wellsites range from

1,994 to 2,004 m (6,542 to 6,576 ft). The drilling rig will be a similar dynamic positioning (DP)

semisubmersible rig. This EIA was prepared for submittal to the Bureau of Ocean Energy

Management (BOEM) in accordance with applicable regulations, including 30 Code of Federal

Regulations (CFR) 550.212(o) and 550.227. The EIA is a project- and site-specific analysis of

Noble’s planned activities under this EP. This EIA complies with guidance provided in existing

Notices to Lessees and Operators (NTLs) issued by the former Minerals Management Service

(MMS) and Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE),

including NTL 2008-G04. 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; BOEM, 2012a) and in multi-lease-sale EISs for the

Western and Central Gulf of Mexico Planning Areas (MMS, 2007b; BOEM, 2012b). The analyses

from these documents are incorporated here by reference.

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 Final Supplemental EIS for the

Central Gulf of Mexico Planning Area, BOEM confirmed that "significant changes to the spill

rates for the entire OCS are not anticipated" (BOEM, 2012b).

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 the Bureau of

Safety and Environmental Enforcement’s (BSEE’s) Final Drilling Safety Rule (75 Federal Register

[FR] 63365) issued following the Macondo incident, the baseline risk of a catastrophic blowout is

estimated to be about once every 26 years.
Mississippi Canyon Blocks 738 and 782 March 2013

Environmental Impact Analysis for Initial Exploration Plan Page 2

Figure 1. Location of Mississippi Canyon Blocks 738 and 782.
Mississippi Canyon Blocks 738 and 782 March 2013

Environmental Impact Analysis for Initial Exploration Plan Page 3

Noble’s Regional Oil Spill Response Plan (OSRP) was originally approved by the MMS on

7 December 2009, and a revised and updated OSRP was submitted to BOEMRE on

August 1, 2010. The OSRP details Noble’s plan for response to rapidly and effectively manage oil

spills that may result from drilling and production operations. Noble 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. Noble’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 Noble’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. All activities planned for MC 738 and 782 are covered under this regional OSRP

in accordance with 30 CFR Part 254.

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

2012-N06

Guidance to Owners and Operators

of Offshore Facilities Seaward of

the Coast Line Concerning Regional

Oil Spill Response Plans

Provides clarification, guidance, and information for

preparation of regional Oil Spill Response Plans.

Recommends description of response strategy for worst

case discharge (WCD) scenarios to ensure capability to

respond to oil discharges is both efficient and effective.

2012-BSEE-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.

2012-JOINT-G01

Vessel Strike Avoidance and

Injured/Dead Protected Species

Reporting

Recommends protected species identification guides be

carried on all Gulf of Mexico petroleum vessels and that

vessel operators and crews maintain a vigilant watch for

marine mammals. Vessels are to slow down or stop to avoid

striking protected species, and operators are required to

report sightings of any injured or dead protected species.

2011-JOINT-G01

Revisions to the List of OCS Blocks

Requiring Archaeological Resource

Surveys and Reports

Provides new information of which Outer Continental Shelf

(OCS) blocks require archaeological surveys and reports and

required survey line spacing in each block. This NTL

augments NTL 2005-G07.

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.
Table 1. (Continued).

Mississippi Canyon Blocks 738 and 782 March 2013

Environmental Impact Analysis for Initial Exploration Plan Page 4

NTL Title Summary

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

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.

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.

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.
Mississippi Canyon Blocks 738 and 782 March 2013

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 BOEM-0142. 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)

The drilling rig proposed for this EP is will be a DP semisubmersible rig. DP semisubmersible rigs

use a global positioning system (GPS), specific computer software, and sensors in conjunction

with their own propellers and thrusters to maintain position. Essentially, through satellite

navigation, 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 station-keeping

adjustment. This allows operations at sea where mooring or anchoring is not feasible.

The drilling rig for the wells proposed in this EP will be on site for an estimated 156 days per

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 DP 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.

A.2 Physical Disturbance to the Seafloor

In water depths of 600 m (1,969 ft) or greater, DP semisubmersibles disturb only a very small

area of the seafloor around the wellbore (SHL) where the bottom template and blowout

preventer (BOP) are located. Depending on the specific well configuration, this area is generally

about 0.25 ha (0.62 ac) (MMS, 2007a).
Mississippi Canyon Blocks 738 and 782 March 2013

Environmental Impact Analysis for Initial Exploration Plan Page 6

Table 2. Matrix of impact-producing factors and affected environmental resources. X = potential impact; dash (--) = no impact or negligible impact.

Environmental Resources

Impact-producing Factors

Drilling Rig

Presence (incl.

noise & lights)

Physical

Disturbance

to Seafloor

Air

Pollutant

Emissions

Effluent

Discharges

Water

Intake

Onshore

Waste

Disposal

Marine

Debris

Support

Vessel/Helo

Traffic

Accidents

Small Fuel

Spill

Oil Spill

(WCD)

Physical/Chemical Environment

Air quality and greenhouse gases -- -- --X(9) -- -- -- -- -- X(6) X(6)

Water quality -- -- -- X -- -- -- -- X(6) X(6)

Seafloor Habitats and Biota

Soft bottom benthic communities -- X -- X -- -- -- -- -- X(6)

High-density deepwater benthic communities -- --(4) -- --(4) -- -- -- -- -- X(6)

Designated topographic features -- --(1) -- --(1) -- -- -- -- -- --

Pinnacle trend area live bottoms -- --(2) -- --(2) -- -- -- -- -- --

Eastern Gulf live bottoms -- --(3) -- --(3) -- -- -- -- -- --

Threatened, Endangered, and Protected Species and Critical Habitat

Sperm whale (endangered) X(8) -- -- -- -- -- -- X(8) X(6,8) X(6,8)

West Indian manatee (endangered) -- -- -- -- -- -- -- X(8) -- X(6,8)

Endangered mysticete whales -- -- -- -- -- -- -- -- -- --

Non-endangered marine mammals (protected) X -- -- -- -- -- -- X X(6) X(6)

Sea turtles (endangered/threatened) X(8) -- -- -- -- -- -- X(8) X(6,8) X(6,8)

Piping Plover (threatened) -- -- -- -- -- -- -- -- -- X(6)

Whooping Crane (endangered) -- -- -- -- -- -- -- -- -- X(6)

Gulf sturgeon (threatened) -- -- -- -- -- -- -- -- -- X(6)

Smalltooth sawfish (endangered) -- -- -- -- -- -- -- -- -- X(6)

Beach mice (endangered) -- -- -- -- -- -- -- -- -- X(6)

Elkhorn coral (endangered) -- -- -- -- -- -- -- -- -- X(6)

Coastal and Marine Birds

Marine birds X -- -- -- -- -- -- X X(6) X(6)

Shorebirds and coastal nesting birds -- -- -- -- -- -- -- X -- X(6)

Fisheries Resources

Pelagic communities and ichthyoplankton X -- -- X X -- -- -- X(6) X(6)

Essential Fish Habitat X -- -- X X -- -- -- X(6) X(6)

Archaeological Resources

Shipwreck sites -- --(7) -- -- -- -- -- -- -- X(6)

Prehistoric archaeological sites -- --(7) -- -- -- -- -- -- -- X(6)

Coastal Habitats and Protected Areas

Beaches -- -- -- -- -- -- -- -- -- X(6)

Wetlands and seagrass beds -- -- -- -- -- -- -- -- -- X(6)

Coastal wildlife refuges and wilderness areas -- -- -- -- -- -- -- -- -- X(6)

Socioeconomic and Other Resources

Recreational and commercial fishing X -- -- -- -- -- -- -- X(6) X(6)

Public health and safety -- -- -- -- -- -- -- -- -- X(6)

Employment and infrastructure -- -- -- -- -- -- -- -- -- X(6)

Recreation and tourism -- -- -- -- -- -- -- -- -- X(6)

Land use -- -- -- -- -- -- -- -- -- X(6)

Other marine uses -- -- -- -- -- -- -- -- -- X(6)

WCD = worst case discharge.
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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 any 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 400 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 30 CFR 250.490(c), Noble is requesting that BOEM classify the lease area as “H2S absent.”

(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 on the list of archaeology survey

blocks (BOEM, 2012c) but 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. The geohazards and

archaeological assessments indicate multiple sonar contacts in the lease area, but none are interpreted

to be historic shipwrecks. A dynamic positioning semisubmersible rig will be used; therefore, seafloor

disturbances due to anchoring will not occur.

(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,

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.
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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 drilling rig operations, 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. GMG290000 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, Louisiana, for recycling and/or

disposal at 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 freshwater 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

not specify requirements for existing facilities (those that started construction before

16 July 2006). The DP drilling rig being considered for use in this EP is a “new” facility as defined

by the NPDES permit and therefore triggers the cooling water intake regulations. The drilling rig

will be in compliance with all cooling water intake requirements of the general NPDES permit.

A.6 Onshore Waste Disposal

Wastes generated during drilling are tabulated in EP Section F. A total of approximately

204,000 lbs of trash will be generated over the life of this project. The trash will be transported
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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

Noble will comply with all regulations relating to solid wastes 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, BOEM 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-BSEE-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

Noble will use existing shorebase facilities at Port Fourchon, Louisiana, for onshore support for

vessel activities. Air transportation (helicopters) will be based at facilities in Houma, Louisiana.

No terminal expansion or construction is planned at either location.

The project will be supported by one crew boat and three supply vessels. The crew boat will

make four round-trips per week, and the supply vessels 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 an estimated four round-trips per week 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. Additional guidelines and regulations specify that helicopters maintain an

altitude of 305 m (1,000 ft) within 91 m (300 ft) of marine mammals (BOEM, 2012d).

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 Noble’s spill response plans. Impacts are analyzed in Section C.
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MMS (2007b) and BOEM (2012b) analyzed 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 BOEM (2012a), 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; BOEM, 2012b).

The median size for spills <1 bbl is 0.024 bbl, and the median size for spills of 1 to 10 bbl is 3 bbl

(BOEM, 2012a). 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; BOEM, 2012b).

The water-soluble fractions of diesel are dominated by two- and three-ringed polycyclic

aromatic hydrocarbons (PAHs), which are moderately volatile (National Research Council,

2003a). 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, 2003a) 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 2 (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 sea

surface area 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.

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 74 miles (119 km)from the nearest shoreline. 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 Noble’s response measures. Slicks from spills are expected to persist for relatively short

periods of time ranging from minutes (<1 bbl) to hours (<10 bbl) to a few days (10 to 1,000 bbl)

and rapidly spread out, evaporate and disperse into the water column (BOEM, 2012b). Because

of the distance of these potential spills on the OCS and their lack of persistence, it is unlikely

that a spill would make landfall prior to dissipation (BOEM, 2012b).
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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 Noble’s response to a spill.

A.9.3 Crude Oil Spill (Worst Case Discharge)

Spill Size. In accordance with requirements of NTL 2010-N06, Noble has estimated a WCD for

this EP as 173,214 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. BOEM 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; BOEM, 2012d). As noted in the Introduction, the baseline risk of a

catastrophic blowout is estimated to be once every 26 years (BSEE Final Drilling Safety Rule,

75 FR 63365).

Included in EP Section H are Noble’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. Noble will also comply

with NTL 2010-N10 and the 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 did it

predict the fate of a release that continues over a period of weeks or months, as in the 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 BOEM to evaluate contact probabilities for spills greater than

1,000 bbl.

To address this criticism, a special OSRA run was conducted for the recent BOEM Western and

Central Gulf of Mexico Planning Area Supplemental EISs (BOEMRE, 2011a; BOEM, 2012b) 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.
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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, the launch point nearest to the project area, are presented in

Table 3.

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: BOEM, 2012b, 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, State 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.
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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, 2003a).

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. BOEM 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 BOEM (2012b) guidance is provided below.

NTL 2012-N06 – Guidance to Owners and Operators of Offshore Facilities Seaward of the

Coast Line Concerning Regional Oil Spill Response Plans: This NTL, effective 10 August 2012,

provides clarification, guidance, and information on the preparation and submittal of

regional OSRPs for owners and operators of oil handling, storage, or transportation facilities,

inclusive of pipelines, located seaward of the coastline. It states that lessees, designated

operators, and pipeline right-of-way holders are responsible for preparation and submission

of these plans. Some of the clarifications and recommended practices in the NTL are based

on lessons learned from the Macondo oil spill response.

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 BOPs on floating facilities. It requires that lessees and operators must

submit a statement signed by an authorized company official with each well permit

application indicating that they will conduct all of their authorized activities in compliance

with all applicable regulations, including the Increased Safety Measures Regulations at

75 FR 63346. The NTL also informs lessees that BOEMRE will evaluate whether the 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
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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, or Development Operations Coordination Documents. The required

supplemental information includes the following: (1) a description of the blowout scenario

as required by 30 CFR 254(b) and 254(h); (2) a description of their assumptions and

calculations used in determining the volume of the WCD required by 30 CFR 254.26; 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

BOEM announced in NTL 2010-N10, which states that BOEM will review to ensure that the

measures are adequate to promptly respond to a blowout or other loss of well control.

Noble submitted an updated Gulf of Mexico Regional OSRP to BOEMRE on 29 September 2011.

The OSRP provides a detailed plan for Noble to respond to rapidly and effectively manage oil

spills that may result from drilling and production operations.

In the event of a WCD, Noble has access to surface and subsea response/containment

capabilities that could be implemented through various organizations under contract. Noble'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 phones; and depth

finders. CGA also offers nine Fast Response Systems staged throughout the Gulf of Mexico

available for offshore use.

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 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. Additional CGA equipment can be referenced on their website:

http://www.cleangulfassoc.com/.

Noble 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

additional available equipment staged throughout the U.S. MSRC equipment staged throughout

the Gulf of Mexico includes seven oil spill response vessels, two fast response vessels, five oil
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Environmental Impact Analysis for Initial Exploration Plan Page 15

spill response barges, five platform supply vessels, and 15 shallow water barges. Various

equipment is outfitted with x-band and infrared technology.

MSRC 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 are available on-line at http://www.msrc.org/.

See EP Section H for a detailed description of Noble’s site-specific response to the WCD for this

plan.

A.9.4 Other Accidents Not Analyzed in Detail

BOEM (2012b) 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 for the

drilling of the wells proposed in this EP.

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; BOEM, 2012b).

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 fluids

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 (>2,380 bbl) quantities of drilling fluids. Riser disconnect

accidents are of particular concern when SBMs are in use (BOEMRE, 2011b).

Vessel Collisions. BOEM 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 lease area,

spilling 1,500 bbl. Diesel fuel is the product most frequently spilled, but oil, natural gas,

corrosion inhibitor, hydraulic fluid, and lube oil have also been released as the result of vessel

collisions. Human error accounted for approximately half of all reported vessel collisions from

2006 to 2009. As summarized in MMS (2007b) and BOEM (2012b), vessel collisions occasionally

occur during routine operations. Some of these collisions have caused spills of diesel fuel or

chemicals. Noble will comply with all USCG- and BOEM-mandated safety requirements to

minimize the potential for vessel collisions.
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Environmental Impact Analysis for Initial Exploration Plan Page 16

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. Noble 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 the NTL 2010-06 package submitted with

the exploration plan, as required. The potential for a loss-of-well-control event will be

minimized by adhering to the requirements of applicable regulations such as the Final Drilling

Safety Rule and NTL 2010-N10, which specify additional safety measures for OCS activities.

H2S Release. Pursuant to 30 CFR 250.490(c), Noble is requesting in the EP that the BOEM

Regional Supervisor, Field Operations, classify the area in the proposed drilling operations as

H2S absent.

B. Affected Environment

The lease area is in the central Gulf of Mexico, 74 miles (119 km) from the nearest shoreline,

and 131 miles (211 km) from the onshore support base at Port Fourchon, Louisiana (Figure 1).

Based on the site clearance survey conducted by Fugro Geoconsulting, Inc. (Fugro) (2013) water

depth at the wellsites is anticipated to be 1,994 to 2,004 m (6,542 to 6,576 ft) (Figure 2). The

seafloor at the proposed wellsites is smooth, featureless, and appears stable. However, there

are several seafloor faults in the vicinity of the proposed wellsites. No seafloor faults will be

penetrated by the proposed wellbores, and the seafloor fault scarps meet the 75 m (245 ft)

standoff distance as outlined by the BOEM in NTL No. 2008-G05. There is an existing pipeline in

the lease area. There is no evidence of fluid expulsion features, or high-density deepwater

benthic communities near the wellsites (Fugro, 2013). A detailed description of the regional

affected environment, 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 is provided in recent

lease sale EISs (MMS, 2007b; BOEM, 2012b). 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 conditions in the offshore waters of the Gulf of Mexico were 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; BOEM, 2012a).
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Figure 2. Bathymetric map of the lease area showing the surface hole locations of Wells A and B in

Mississippi Canyon Block 738 and A, B, C, and D in Mississippi Canyon Block 782.
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Environmental Impact Analysis for Initial Exploration Plan Page 18

The lease area is located approximately 34 miles (54 km) south-southeast of the Macondo spill

site. Based on an analysis of satellite imagery, the surface slick did extend over the lease area,

and there is the possibility that water quality in the lease area was briefly 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; BOEM, 2012a,b,d).

C. Impact Analysis

This section analyzes the potential direct and indirect impacts of routine activities and accidents.

Impacts have been analyzed extensively in multi-lease-sale EISs for the Western and Central Gulf

of Mexico Planning Areas (MMS, 2007b; BOEM, 2012b). 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).

BOEM 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; BOEM, 2012b).

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 and 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 described in recent lease

sale EISs, the incremental contribution to cumulative impacts from activities similar to Noble’s

proposed activities is not significant and will not cause or contribute to a violation of any
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Environmental Impact Analysis for Initial Exploration Plan Page 19

National Ambient Air Quality Standard (NAAQS) (MMS, 2007b, 2008). Since the BOEM

completed the lease sale EISs, the USEPA has adopted a new short-term NAAQS for nitrogen

dioxide (NO2). 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 Noble’s proposed EP are not likely to contribute to violations of any

NAAQS onshore.

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).

Because of 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 100 miles (161 km) from the Breton

Wilderness Area, and no air quality impacts on the Wilderness Area are expected. Noble will

comply with all BOEM requirements regarding air emissions.

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; BOEM, 2012b,d). The

probability of a small spill would be minimized by Noble’s preventative measures during routine

operations, including fuel transfer. In the unlikely event of a spill, implementation of Noble’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.
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Environmental Impact Analysis for Initial Exploration Plan Page 20

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 sea surface area 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 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; BOEM, 2012b,d).

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.

Because of the lease area location (74 miles [119 km])from the nearest shoreline, 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 34 miles (54 km) from the Macondo spill site. Based on

the general circulation pattern seen in the Gulf of Mexico and satellite imagery, the surface slick

from that discharge did extend over the lease area during the spill, and there is the possibility

that water quality in the lease area was affected briefly.

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
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Environmental Impact Analysis for Initial Exploration Plan Page 21

Port Fourchon, Louisiana. 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. 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; BOEM, 2012a,b). The probability of a small

spill would be minimized by Noble’s preventative measures during routine operations, including

fuel transfer. In the unlikely event of a spill, implementation of Noble’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 sea surface area 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, 2003a). The constituents of these oils are light

to intermediate in molecular weight and can be readily degraded by aerobic microbial oxidation.

Because the density of diesel is less than the density of seawater, diesel will not sink and pool on

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, 2003a) 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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Environmental Impact Analysis for Initial Exploration Plan Page 22

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; BOEM, 2012b,d). 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 sediments and be removed from the water column (Operational

Scientific Advisory Team [OSAT], 2010).

Because of the lease area location (74 miles [116 km] from the nearest shoreline), 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 depth at the proposed project area is approximately 1,994 to 2,004 m (6,542 to 6,576 ft).

The seafloor at the proposed wellsites is smooth, featureless and stable. The immediate regions

around the proposed well locations show several seafloor faults in the vicinity of the proposed

wellsites. These seafloor faults will not be penetrated by the proposed wellbores. No areas of

possible hard bottom or microseepages were seen within 610 m (2,000 ft) of any of the wellsites

(Fugro, 2013).

Based on the absence of hard bottom areas detected by side-scan sonar during the site

clearance survey, the seafloor within 610 m (2,000 ft) of the wellsites 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 within

610 m (2,000 ft) of the wellsites, and the presence of chemosynthetic communities is considered

negligible (Fugro, 2013).

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 collected at stations in water depths similar to the proposed drilling

area.
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Environmental Impact Analysis for Initial Exploration Plan Page 23

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 (Adapted from: Wei, 2006; Rowe and Kennicutt, 2009).

Station Water Depth

(m)

Abundance

Meiofauna

(individuals/m2)

Macroinfauna

(individuals/m2)

Megafauna

(individuals/ha)

S37 2,384 291,179 2,192 1,451

S36 1,828 799,963 4,481 359

Meiofaunal and megafaunal abundances from Rowe and Kennicutt (2009); macroinfaunal abundance from

Wei (2006).

Densities of meiofauna (animals passing through a 0.5-mm sieve but retained on a 0.062-mm

sieve) in water depths representative of the lease area (1,994 to 2,004 m [6,542 to 6,576 ft] )

typically range from approximately 84,000 to 800,000 individuals/m2(Rowe and

Kennicutt, 2009). Nematodes, nauplii, and harpacticoid copepods were the three dominant

meiofaunal groups, accounting for about 90% of total abundance.

The benthic macroinfauna is characterized by small mean individual sizes and low densities,

both of which reflect 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 lease area are

expected to be about 1,550 individuals/m2.

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 3E which includes the west flank of the lower Mississippi

Fan, lower Mississippi Canyon, lower De Soto Canyon, lower West Florida Terrace, deep

Mississippi Fan and one location at the base of the Sigsbee Escarpment with stations ranging in

depth from 2,275 to 3,314 m (7,464 and 10,873 ft). The most abundant species in Zone 3E were

the polychaetes Paraonella monilaris and Tharyx marioni; the bivalves Heterodonta spp. B and

C; and the isopod Macrostylis sp.

Megafaunal densities from nearby stations ranged from 359 to 1,600 individuals/ha. Common

megafauna included motile groups such as decapods, ophiuroids, holothurians, and demersal

fishes as well as sessile groups such as sponges and anemones.

Bacteria also are 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/m2in the top 15 cm (6 in.) of sediments (Rowe and Kennicutt, 2009).

IPFs potentially affecting benthic communities are physical disturbance to the seafloor, effluent

discharges (drilling muds and cuttings), and a large oil spill (WCD) resulting 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.
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Environmental Impact Analysis for Initial Exploration Plan Page 24

Physical Disturbance to the Seafloor

In water depths such as are encountered in the lease area, DP semisubmersibles disturb the

seafloor only around the wellbore (SHL) where the bottom template and BOP 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 the DP rig 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 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 the 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.
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Environmental Impact Analysis for Initial Exploration Plan Page 25

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).

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, 2003a).

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 site is approximately 66 miles (106 km)

north-northeast of the lease area in Viosca Knoll Block 826. The nearest identified deep water

coral communities are in MC 426, 24 miles (39 km) north-northwest of the lease area.

The geohazards assessment of the lease area did not identify any features that could support

high-density deepwater benthic communities within 610 m (2,000 ft) of the proposed drilling

mud/cuttings discharge locations (Fugro, 2013).

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.
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Physical Disturbance to the Seafloor

In water depths such as are encountered in the lease area, DP semisubmersibles disturb the

seafloor only around the wellbore (SHL) where the bottom template and BOP 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 the 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. Based

on the Fugro (2013) report, there will be no impacts on chemosynthetic or deepwater coral

communities from this project.

Impacts of Effluent Discharges

The site clearance survey (Fugro, 2013) 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

negligible. 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. Oil plumes that contact sensitive benthic communities before degrading could

potentially impact the resource (BOEM, 2012b). 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 the 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.
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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

habitats. Sublethal effects could be long-lasting and affect the resilience of coral colonies to

natural disturbances (e.g., elevated water temperature and diseases) (BOEM, 2012d).

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 by 40 m (50 by 130 ft) was covered by what

appeared to be a brown flocculent substance (floc). 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. Based on hopanoid petroleum biomarkers from the floc, researchers

concluded that it contained oil from the Macondo spill. The injured and dead corals were in an

area where a subsea plume of oil had been documented during the spill in June, 2010; corals

elsewhere in the Gulf of Mexico outside the area affected by the plume did not appear to be

experiencing higher mortality. The research team concluded that the observed coral injuries

likely resulted from exposure to the subsurface oil plume (White et al., 2012).

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 Sackett Bank in the

West Delta Area, South Addition, Block 147, 79 miles (128 km) west-northwest 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, 66 miles (107 km) north of

the lease area.
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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.

C.2.5 Eastern Gulf Live Bottoms

The lease area is not covered by the Live Bottom (Low-Relief) Stipulation, which pertains to

seagrass communities and low-relief hard-bottom reef within the Eastern Gulf of Mexico

Planning Area blocks in water depths of 100 m (328 ft) or less and portions of Pensacola and

Destin Dome Area blocks in the Central Gulf of Mexico Planning Area. The nearest block

covered by the live bottom stipulation, as defined by NTL 2009-G39, is Destin Dome Block 573,

approximately 85 miles (136 km) north-northeast of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to eastern Gulf 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.
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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

Sei whale Balaenoptera borealis E X

a

-- None

Blue whale Balaenoptera musculus E Xa-- None

Fin whale Balaenoptera physalus E X

a

-- None

North Atlantic right whale Eubalaena glacialis E X

a

-- None

Humpback whale Megaptera novaeangliae E Xa-- None

Sperm whale Physeter macrocephalus E X -- None

West Indian manatee Trichechus manatus

latirostris E -- X Florida (Peninsular)

Sea Turtles

Loggerhead turtle Caretta caretta T X X None

Green turtle Chelonia mydas T, EbX 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.

As mandated by the ESA, MMS 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
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letter dated 14 September 2007. The USFWS concurred with MMS’s determination that

proposed actions of the 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.

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

(BOEM, 2012b). The existing consultation recognizes that BOEM-required mitigations and other

reasonable and prudent measures should reduce the likelihood of impacts from all

BOEM-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 mouse. Critical habitat has been designated for all of these species as indicated in Table 5

and discussed in individual sections.

Two other coastal species (Bald Eagle and Brown Pelican) discussed in the MMS (2007b) and

BOEM (2012b) lease sale EISs are no longer federally listed as endangered or threatened. These

are discussed in Section C.4.2, Shorebirds and Coastal Nesting Birds.

There are five sea turtle and six marine mammal species that are currently listed as endangered

and threatened by the ESA and known to occur within OCS and slope waters of the Gulf of

Mexico. The listed sea turtles include the leatherback turtle, Kemp's ridley turtle, hawksbill

turtle, loggerhead turtle, and green turtle. Listed marine mammal species include one

odontocete (toothed) whale (sperm whale) and five mysticete (baleen) whales (blue whale, fin

whale, humpback whale, North Atlantic right whale, and sei whale)(Pritchard, 1997; Würsig et

al., 2000). No critical habitat has been designated for these species in the Gulf of Mexico.

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., 2012). No critical habitat for the sperm whale has been designated in the Gulf of Mexico.
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The distribution of sperm whales in the Gulf of Mexico is correlated with mesoscale physical

features such as eddies associated with the 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 NTL 2012-BSEE-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 the Gulf of Mexico, the impacts from many of these threats are identified as either low or

unknown (BOEMRE, 2011a; BOEM, 2012b).

Impacts of Drilling Rig Presence, Noise, and Lights

Noise generated from the drilling rig and from routine drilling activities may be audible to sperm

whales and so has the potential to disturb individuals near the lease area. As discussed in

Section A.1, the bandwidth of sounds generated by the drilling rig is approximately 100 to

500 Hz. The anatomy of the sperm whale ear suggests that it hears in the ultrasonic (>20 kHz)

range. The sperm whale may possess better low frequency hearing than some of the other

odontocetes, although not as low as many baleen whale species that produce sounds within a

bandwidth between 30 Hz and greater than 5 kHz (Wartzok and Ketten, 1999). Southall et al.

(2007) lists sperm whales in the same hearing group (mid-frequency cetaceans), as “dolphins,”

toothed whales, beaked whales, and bottlenose whales (estimated hearing range of 150 Hz to

160 kHz). Generally, most of the acoustic energy from sperm whales is present at frequencies

below 4 kHz, although diffuse energy up to and past 20 kHz has been reported, with source

levels up to 236 dB re 1 μPa at 1 m. Other studies indicate sperm whales’ wideband clicks 

contain energy between 0.1 and 20 kHz (Weilgart and Whitehead, 1993; Goold and Jones,

1995).
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Some sounds produced by the drilling rig may be emitted at levels that could potentially disturb

individual whales or mask the sounds animals would normally produce or hear. Observations of

sperm whales near offshore oil and gas operations suggest an inconsistent response to

anthropogenic noise (Jochens et al., 2008). Barkaszi et al. (2012) showed that Gulf of Mexico

sightings distances and surface activity durations were greater for sperm whales during full

power seismic surveys than during no-firing periods on seismic vessels, indicating a potential

avoidance response to some sound sources. In contrast, Davis et al. (2000) noted that sighting

frequency in the northern Gulf of Mexico did not differ significantly among different acoustic

levels, including vessel traffic and active seismic surveys. Most observations of behavioral

responses of marine mammals to anthropogenic sounds, in general, have been limited to shortterm behavioral responses, which included the cessation of feeding, resting, or social

interactions (NMFS, 2009). Sounds produced during drill rig operations are generally constant

(rather than pulsed or intermittent) and at levels that may be louder than, and of a similar

frequency to, the auditory signal received by sperm whales. Animals can determine the

direction from which a sound arrives based on cues, such as difference in arrival times, sound

levels, and phases at the two ears. Thus, an animal’s directional hearing capabilities have a

bearing on its vulnerability to masking (National Research Council, 2003b). Behavioral changes

for marine mammals such as the sperm whale to auditory masking sounds may include

producing more calls, longer calls, or shifting the frequency of the calls (NMFS, 2009). For

example, killer whales, also a mid-frequency odontocete, increased the amplitude of their calls

to avoid masking by boat noise (Holt et al. 2009).

The drilling rig used during the proposed activity will be located within a deepwater, open ocean

environment and will remain stationary during drilling operations. Sounds generated by the rig

and by drilling operations will be generally continuous (with some variability in sound level,

considering thruster activity). This analysis assumes that the continuous nature of sounds

produced by the drilling rig will provide individual whales with cues relative to the direction and

relative distance (sound intensity) of the sound source, and the fixed position of the drilling rig

will provide multiple options for active avoidance of potential physical impacts. 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).

In addition, 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. Drilling-related noise associated with this

project will contribute to increases in the ambient noise environment of the Gulf of Mexico, but

it is not expected in amplitudes sufficient to cause either hearing or behavioral effects to sperm

whales.

Drilling rig lighting and rig presence are not identified as IPFs for sperm whales in recent lease

sale EISs (MMS, 2007b; BOEM, 2012a,b,d) 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
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concerning the frequency of vessel strikes are presented in a recent lease sale EIS

(MMS, 2007b). To reduce the potential for vessel strikes, the BSEE and BOEM issued

NTL 2012-JOINT-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 safety permits,

when mother/calf pairs, pods, or large assemblages of cetaceans are observed near an

underway vessel. 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 NTL 2012-JOINT-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 population level. With implementation of the vessel strike

avoidance measures requirement to maintain a distance of 91 m (300 ft) from sperm whales,

the NMFS concluded that the potential for harassment of sperm whales would be reduced to

discountable levels.

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 animal. Although responses are possible (Smultea

et al., 2008), the NMFS (2007) and BOEM (2012d) 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; BOEM, 2012a,b,d) 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 Noble’s preventative measures during routine

operations including fuel transfer. In the unlikely event of a spill, implementation of Noble’s

OSRP will mitigate and lessen the potential for impacts on sperm whales. Given the open ocean
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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 sea surface area 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; BOEM, 2012a,b,d) and by NMFS (2007). For this EP, there are no unique

site-specific issues with respect to spill impacts on these animals.

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, 2011). 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, 2011). Ackleh et al. (2012) hypothesized that sperm whales may have

temporarily relocated away from areas near the Macondo spill in 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 NTL 2012-JOINT-G01 to reduce

the potential for striking or disturbing these animals.

C.3.2 West Indian Manatee (Endangered)

Most of the Gulf of Mexico 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).
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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 74 miles (119 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 NTL 2012-BSEE-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, BSEE and BOEM issued NTL 2012-JOINT-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 relatively low altitudes 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. In addition,

guidelines and regulations specify that helicopters maintain an altitude of 305 m (1,000 ft)

within 91 m (300 ft) of marine mammals (BOEM, 2012a,d). This mitigation measure will

minimize the potential for disturbing manatees, and no significant impacts are expected.

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, 2011). 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, 2011).

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 NTL 2012-JOINT-G01 to reduce the potential for striking or disturbing these

animals, and therefore no significant impacts are expected.
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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.

Because of 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; BOEM, 2012a,b,d), 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, including 2 species of

mysticete whales, 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

nonendangered 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 species of nonendangered 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 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
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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 nonendangered cetaceans in the deepwater environment are the pantropical spotted

dolphin, spinner dolphin, and Clymene dolphin.

Bottlenose dolphins. The bottlenose dolphin (Tursiops truncatus) is a common inhabitant of the

northern Gulf of Mexico, particularly within continental shelf waters. There are two ecotypes of

bottlenose dolphins, a coastal form and an offshore form, which are genetically isolated from

each other (Waring et al., 2012). The offshore form of the bottlenose dolphin may occur within

the lease area. Inshore populations of coastal bottlenose dolphins in the northern Gulf of

Mexico are separated into 37 geographically distinct population units, or stocks, for

management purposes by the NMFS (Waring et al., 2012). NMFS (2013) has proposed to classify

the Gulf of Mexico Northern Coastal Stock, Western Coastal Stock, and all 32 of the Bay, Sound,

and Estuarine Stocks as strategic stocks. A “strategic” stock is defined by the MMPA as a marine

mammal stock

 for which the level of direct human-caused mortality exceeds the potential biological

removal level;

 which, based on the best available scientific information, is declining and is likely to be listed

as a threatened species under the ESA within the foreseeable future; or

 which is listed as a threatened or endangered species under the ESA, or is designated as

depleted under the MMPA.

The strategic stock designation in this case was based primarily on the occurrence of an

“unusual mortality event” of unprecedented size and duration that has affected these stock

areas. This unusual mortality event began in February 2010 and is ongoing. Carmichael et al.

(2012) hypothesized that the unusual number of bottlenose dolphin strandings in the northern

Gulf of Mexico during this time may have been associated with environmental perturbations

including sustained cold weather and the Macondo spill in 2010 as well as large volumes of cold

freshwater discharge in the early months of 2011.

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 those produced

by OCS drilling activities (Richardson et al., 1995). Noise generated during drilling operations is

generally continuous and fixed in location. Noise intensity associated with these operations is

relatively weak. Stronger noise levels will occur during thruster use in dynamic positioning.

Thruster noise impacts would be expected at greater distances than vessel noise alone (LGL

Ecological Research Associates, Ltd., 2006) but are dependent on variables relating to thruster
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Environmental Impact Analysis for Initial Exploration Plan Page 38

type and usage. It is expected that marine mammals within or near the lease area would be

able to detect the presence of the drilling rig and avoid exposure to higher energy sounds,

particularly within an open ocean environment. Some odontocetes have shown increased

feeding activity around lighted platforms at night (Todd et al., 2009). Even temporary drill rigs

present an attraction to pelagic food sources that may attract both cetaceans and sea turtles.

Therefore, prey congregation could pose an attraction to protected species that exposes them

to higher levels or longer durations of noise that might otherwise be avoided. There are other

OCS facilities and activities near the lease area, and the region as a whole has a large number of

similar sources. Species in the northern Gulf of Mexico have been exposed to noise from

anthropogenic sources for a long period of time and over large geographic areas and likely do

not represent a naïve population with regard to sound (National Research Council, 2003b). Due

to the limited duration of drilling activities, this project would represent a temporary

contribution to the overall noise regime within the lease area, and potential impacts are

expected to be biologically insignificant 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; BOEMRE, 2011a; BOEM, 2012a,b).

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, BSEE and BOEM issued

NTL 2012-JOINT-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

NTL 2012-JOINT-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. In addition, guidelines and regulations specify that helicopters maintain

an altitude of 305 m (1,000 ft) within 91 m (300 ft) of marine mammals (BOEM, 2012a,d).

Maintaining this altitude will minimize the potential for disturbing marine mammals, and no

significant impacts are expected (BOEM, 2012a,d).

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b;

BOEM, 2012a,b), 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.
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The probability of a fuel spill will be minimized by Noble’s preventative measures during fuel

transfer. In the unlikely event of a spill, implementation of Noble’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

within 24 hours. The sea surface area 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, 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

marine mammals, no significant impacts would be expected.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b;

BOEM, 2012a,b). 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, 2011).

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, 2011).

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 NTL 2012-JOINT-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 turtle (Dermochelys coriacea), Kemp's ridley turtle (Lepidochelys kempii), and

hawksbill turtle (Eretmochelys imbricata) turtles are endangered. The loggerhead turtle

(Caretta caretta) is currently a threatened species; however, in March 2010, NMFS and USFWS
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Environmental Impact Analysis for Initial Exploration Plan Page 40

proposed to list the Northwest Atlantic Ocean population of loggerhead turtles as endangered

(75 FR 12598). 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).

Leatherback and loggerhead turtles 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 on the northern Gulf of Mexico coast 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, 2012);

 Kemp’s ridley turtles – The main Kemp’s ridley nesting site is Rancho Nuevo beach,

Tamaulipas, Mexico (NMFS et al., 2011). 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-BSEE-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. 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

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.

Impacts of Support Vessel and Helicopter Traffic

Noise generated from support vessel traffic has the potential to disturb sea turtles, and there is

also a risk of vessel strikes. Data show that vessel strike is one cause of sea turtle mortality in
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Environmental Impact Analysis for Initial Exploration Plan Page 41

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, BSEE and BOEM issued NTL 2012-JOINT-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).

Noise generated from support 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; BOEM, 2012a,b)

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 Noble’s preventative measures during fuel

transfer. In the unlikely event of a spill, implementation of Noble’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 sea surface area 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 (MMS, 2007b; NMFS, 2010b; BOEM, 2012b,d). 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 74 miles (119 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.

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
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Environmental Impact Analysis for Initial Exploration Plan Page 42

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 Noble’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 NTL 2012-JOINT-G01 to reduce the

potential for striking or disturbing these animals, and therefore no significant impacts are

expected.

The extent and scope of the Macondo spill represents new information not assessed in the

existing ESA Section 7 consultation under the current Five-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

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 (BOEM, 2012b).

BOEMRE (2011a) and BOEM (2012b) 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.

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
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Environmental Impact Analysis for Initial Exploration Plan Page 43

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).

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 73 miles (118 km) from the nearest shorelines inhabited by Piping Plovers

(Figure 3). The revised OSRA results (BOEMRE, 2011a; BOEM, 2012b) 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. Noble has

extensive resources available to protect and rehabilitate wildlife in the event of a spill reaching

the shoreline, as detailed in the OSRP.
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Figure 3. Location of selected environmental features in relation to the lease area.
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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 nonmigrating 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 recent lease

sale EISs (MMS, 2007b; BOEM, 2012a). A large oil spill (WCD) is the only IPF potentially affecting

Whooping Cranes. A small fuel spill in the lease area would 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

497 miles (800 km) from its critical habitat designated in the Aransas NWR. The revised

OSRA modeling (BOEM, 2012b) 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.

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, Noble 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 lease sale EIS
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(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;

BOEM, 2012a,b) and by NMFS (2007). For this EP, there are no unique site-specific issues with

respect to this species.

The lease area is approximately 133 miles (214 km) from the nearest Gulf sturgeon critical

habitat. The revised OSRA modeling (BOEM, 2012b) 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).

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 under the

ESA on 1 April 2003. 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; BOEM, 2012a) and by the NMFS (2007)

in its Biological Opinion. For this EP, there are no unique site-specific issues with respect to

smalltooth sawfish.
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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 mouse (Peromyscus polionotus) occur on the barrier

islands of Alabama and the Florida Panhandle. They are the Alabama, Choctawhatchee,

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;

BOEMRE, 2011a; BOEM, 2012a). 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 137 miles (220 km) north from the nearest beach mouse critical habitat.

The revised OSRA modeling summarized in Section A.9.3 predicts that a spill in the 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 coral species in waters ranging from 1 to 5 m (3.3 to 16 ft) deep

in tropical and subtropical waters. In the northern Gulf of Mexico, 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 of Mexico. 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 Garden Banks because of the water depth of the area. Although
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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). 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.

The distributions and relative densities of seabirds within the deepwater areas of the Gulf of

Mexico, including the project area, vary temporally (i.e., seasonally) and spatially. In GulfCet II

studies, species diversity and densities varied by hydrographic environment and by the presence

and relative location of mesoscale features such as Loop Current eddies that may enhance

nutrient levels and productivity of surface waters where these seabird species forage (Hess and

Ribic, 2000).

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 NTL 2012-BSEE-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.,
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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 study in the North Sea indicated that rig lighting causes circling behavior in various birds,

especially on cloudy nights; apparently the birds’ geomagnetic compasses are 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). The OSPAR workshop (OSPAR

Commission, 2012) noted that this circling increases the risk of collisions leading to traumas and

deaths and may interrupt their migration. 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. In laboratory experiments, Poot et al.

(2008) found the magnetic compass of migratory birds to be wavelength dependent. Migratory

birds require light from the blue-green part of the spectrum for magnetic compass orientation,

whereas red light (visible long-wavelength) disrupts their magnetic orientation. They designed a

field study to test if and how changing light color influenced migrating birds under field

conditions. During field studies they found that nocturnally migrating birds were disoriented

and attracted by red and white light (containing visible long-wavelength radiation), whereas

they were clearly less disoriented by blue and green light (containing less or no visible

long-wavelength radiation) (Poot et al., 2008). 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.

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; BOEM,

2012 a,b,d). 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 Noble’s preventative measures during routine

operations including fuel transfer. In the unlikely event of a spill, implementation of Noble’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.
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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 sea surface area 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;

BOEM, 2012 a,b,d). For this EP, there are no unique site-specific issues with respect to spill

impacts on these animals.

BOEM 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; BOEM, 2012b).

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 [<656 ft]). 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.

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 (USFWS, 2011). 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; BOEM, 2012a).
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The Brown Pelican (Pelecanus occidentalis) was delisted from Federal endangered status in 2009

(USFWS, 2010c). However, this species remains listed as endangered on the Louisiana list of

Endangered Species (Louisiana Department of Wildlife and Fisheries, 2013), 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 74 miles (119 km)from the

nearest shoreline. 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 NTL 2012-BSEE-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

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 Noble’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 are 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
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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 USFWS (2011), 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

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.

While the Macondo spill had direct and indirect impacts to coastal and marine birds, it is

premature to conclude impacts over a long period (BOEM, 2012b). Modeling of Macondo spill

related bird impacts is underway by NRDA, but results have not yet been released.

Antonio et al. (2011) modeled bird-mortality from the Macondo spill showing cumulative

carcass numbers and mortality rate increasing exponentially from the start of the Macondo spill

until the mortality rate began to decline after the 97th day of the spill. Note that the collected

animals would be a small subset of the total number of impacted birds and therefore, the

collected animals would represent an underestimated measure of the overall impact of the

Macondo event (BOEM, 2012b).
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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

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,
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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. The rig considered for use for activities described in this EP is a "new" facility

as defined by the NPDES permit and therefore will comply with 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;

BOEM, 2012a,d). 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 Noble’s preventative measures during routine

operations including fuel transfer. In the unlikely event of a spill, implementation of Noble’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.

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 sea surface area 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 BOEM (2012b) 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 are, located approximately 58 miles

(93 km) north 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

migratory species with EFH at or near the lease area include the following species and life stages

(NMFS, 2009):
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 Atlantic bluefin tuna (spawn, eggs,

larvae)

 Bigeye tuna (juveniles, adults)

 Bigeye thresher shark (all)

 Blue marlin (juveniles, adults)

 Longbill spearfish (juveniles, adults)

 Longfin mako shark (all)

 Oceanic whitetip shark (all)

 Skipjack tuna (spawn)

 Swordfish (larvae, juveniles, adults)

 White marlin (juveniles, adults)

 Yellowfin tuna (spawn, juveniles, adults)

 Whale shark (all)

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. However, NOAA did classify

the bluefin tuna as a species of concern, effectively placing the species 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 BOEM’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; BOEM, 2012b).

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 HAPC is Jakkula Bank, located approximately 201 miles (323 km) to the

west of the lease area.

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,
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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 Noble’s preventative measures during routine

operations including fuel transfer. In the unlikely event of a spill, implementation of Noble’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; BOEM, 2012a,d). 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 sea surface area 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

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 features located approximately 58 miles (93 km) from the lease area along the shelf

edge south of Louisiana. A small fuel spill would float and dissipate on the sea surface and would

not contact these features.
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Impacts of a Large Oil Spill (WCD)

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b; BOEM, 2012a,d). 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 in 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 features, located 58 miles (93 km) north of the lease area, are 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 BOEM (2012b) 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 BOEM-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), a survey is now required for exploration and development projects.

The lease area is on the list of OCS blocks with a high potential for historic shipwrecks (BOEM,

2012c). Two sonar contacts interpreted as unidentified debris on the seafloor lie within 610 m

(2,000 ft) of the proposed wellsites. There were no indications of wrecks or other archaeological

resources detected during the site clearance survey (Fugro, 2013). Noble will abide by the

applicable requirements of NTL 2005-G07, which stipulate that work be stopped at the project

site if any previously undetected archaeological resource is discovered after work has begun

until appropriate surveys and evaluations have been completed.
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Because there are no shipwreck sites in the lease area, there are no routine IPFs that are likely

to affect shipwrecks. Impacts of a large oil spill (WCD) are the only IPFs 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 Noble 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. Noble 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 91 m

(300 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. suggests that sea level at

12,000 years B.P. would have been approximately 45 to 60 m (148 to 197 ft) below the

present-day sea level (Coastal Environments, Inc., 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
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the 60-m (197-ft) water depth as the seaward extent for archaeological site potential in Gulf of

Mexico region.

With a water depth between 1,994 to 2,004 m (6,542 to 6,576 ft), the lease area is 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 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; BOEM, 2012a,b,d) 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 relate to support vessel

traffic. The support bases at Port Fourchon and Houma, 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

74 miles (119 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.

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.
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Impacts of a Large Oil Spill (WCD)

Potential spill impacts on coastal habitats are discussed in recent EISs (MMS, 2007b;

BOEM, 2012a,b,d). 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 recent lease sale EISs (MMS, 2007b; BOEM, 2012b) and Noble’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: BOEM, 2012b).

County or Parish, State Wildlife Refuge, Wilderness Area, or

State/National Park

Cameron County, Texas

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

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
Table 6. (Continued).

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County or Parish, State Wildlife Refuge, Wilderness Area, or

State/National Park

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. Anahuac 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

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
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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;

BOEMRE, 2011a; BOEM, 2012b).

C.8 Socioeconomic and Other Resources

C.8.1 Recreational and Commercial Fishing

BOEM 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; BOEM, 2012b).

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 (Pleoticus robustus) are caught by

trawlers in water depths of about 250 to 550 m (820 to 1,804 ft). Tilefishes (primarily

Lophalotilus chamaeleonticeps) 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

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 types of potential accidents are also addressed below – a small fuel spill and a large

oil spill (WCD).
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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 Noble’s preventative measures during routine

operations including fuel transfer. In the unlikely event of a spill, implementation of Noble’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 sea surface area 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;

BOEM, 2012b,d). 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.

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 Noble’s preventative measures during routine

operations including fuel transfer. In the unlikely event of a spill, implementation of Noble’s
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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 74 miles (119 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, e.g., 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

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 Noble’s preventative measures during routine

operations including fuel transfer. In the unlikely event of a spill, implementation of Noble’s
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Environmental Impact Analysis for Initial Exploration Plan Page 66

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;

BOEM, 2012a,b,d). 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 BOEM (2012b), 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 six-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

BOEM 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; BOEM, 2012b).

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 NTL 2012-BSEE-G01 will minimize the chance of trash or debris being lost

overboard from the drilling rig and subsequently washing up on beaches.

Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Noble’s preventative measures during routine

operations including fuel transfer. In the unlikely event of a spill, implementation of Noble’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.
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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; BOEM, 2012a,b,d). 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 (BOEM, 2012b) 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; BOEMa,b,d), 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 three-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;

BOEM, 2012a,b,d). 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 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

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.
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C.8.6 Other Marine Uses

The lease area is not located within any USCG-designated fairway or shipping lane or Military

Warning Area. Noble will comply with BOEM requirements and lease stipulations to avoid

impacts on uses of the area by military vessels and aircraft.

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 or Military Warning

Area. In the event of a large spill requiring numerous response vessels, coordination would be

required to manage the vessel traffic for safe operations. Noble 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 surveys conducted by Fugro (2013) 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.

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 rig under
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Environmental Impact Analysis for Initial Exploration Plan Page 69

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 Noble 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 Noble’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 Ocean Sciences Inc. Contributors included:

 C. Chandool, Ph.D. (Senior Scientist);

 C. Kalloo (Senior Scientist);

 M. John Thompson (Senior Scientist);

 Neal Phillips, Ph.D. (Senior Scientist);

 Keith VanGraafeiland (GIS/Remote Sensing Specialist);

 Kristen L. Metzger (Library and Information Services Director); and

 Pamela S. Jones (Technical Editor).
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Section O

Administrative Information

A. Exempted Information Description

The proposed bottom-hole locations of the planned wells have been removed from the public information

copy of the EP as well as any discussions of the target objectives, geologic or geophysical data, and any

interpreted geology.

B. Bibliography

Not applicable.

Noble Energy, Inc. Page O-1

Initial Exploration Plan 04/09/2013

Mississippi Canyon 738 & 782 (OCS-G 33755 & 33757)