i In Reply Rej'&r Toi FO-2-1 Mey 11, 1987

Marathon Oi l Company Attentions Hr C . V. Truby Post Off ic* Box 53266 Lafayette, Louisiana 70505

Gentlenens

Reference 1s made to your I n i t i a l Flan of Exploration and Enviromnental Report received Apri l 29. 1967, for Leaae OCS-G 5466, B loc* 145, Sc t t .Marsh Island Area. Th is plan includes the a c t i v i t i e s proposed for Wells ri through E*

In accordance with 30 CFR &0 .34 , revised Decern er 13, 1979* ana our le t te r dated January 29* 1979, th is plan I s hereby detenstned to oe conplete and I s nos ueing considered for approval.

Your plan control manner 1s N-2692 ano" should be referenced 1n yoor coMfMtoIcation ana correspondence concerning th is plan.

Sincerely yours.

(Orig. Sgd.) A. Donald Giw Q f i * 3* &our$*cle

Regional Supervisor F ie ld Operations

bcc: Lease UDS-G 5466 (OPS-3-2) (FIU ROOM) (OPS-3-4 /Public Info. Copy of the plan and ER (PUBLIC RECORDS)

ADGoben ;dsl:4/30/87spoocoii

Office ( Prcgrv: -;c«a

MAY 1 :• )987

Information SehrtSSl

Gulf Coast Region Production United States

Marathon Oil Company

P.O. Box 53266 OCS Lafayette, Louisiana 70505-3266 Telephone 318/233-8240

r

i April 24, 1967

Minerals Management Service Mr. Daniel Bourgeois 1201 Elrti^-od Park Blvd. New Orleans, IA 70123-2394

PLAN CF EXPLOFATICN SOUTH MARSH ISLAND BLOCK 145, OCS-G-5466

In compliance with 30 CFR 250.34-1, the attached Plan of Exploration i a respectfully submit ted.

The Plan includes:

- A brief description of scheduling and work to be done; - A l i s t of proposed sites to be dril led; - A proprietary plat showing proposed surface and botton

hole locations; - A non-proprietary plat showing surface location of each

site and lease block relative to shore line; - A Seismic Structure top. Pressure Map, and Cross Section; - A shallow hazards interpretation for each site; - A typical jack-up rig and diverter system; - A l i s t of water base and o i l bas^ mud components; - An Environmental Reoort.

Should additional infonnation be required, please contact me immediately.

pdh

Attachments

EXPLORATORY BUT I.TNG PLAN SOUTH MARSH ISLAND BLOCK 145

j OCS-G-5466

Marathon proposes to d r i l l at least five (5) exploratory wells on the

subject lease, OCS-G-5466 for the purpose of evaluating the potential of

the lease to produce commercial quantities of o i l and gas. Each

exploratory well is projected to require a minimum of 110 days to d r i l l

and evaluate. Present scheduling indicates that the f i r s t well may be

spudded as early as June 1, 1967. Because a five (5) well program w i l l

require at least 550 days of continuous d r i l l i n g activity, the conplete

program, as affected by present and future rig scheduling, is projected

to extend through Noverber, 1988.

The service base fbr this exploration program w i l l be Berwick, Louisiana.

Numerous service f a c i l i t i e s , including mud companies, pipe companies,

dock space, warehouses, storage yards, helipads, and the like are found

in t h i s vicinity. These existing f a c i l i t i e s w i l l be utilized and are

considered adequate to handle the various jobs without any expansion or

significant changes in activity levels.

A deep water jack-up type d r i l l i n g r i g is anticipated tc be utilized for

the subject exploratory program. The r i g is equipped with typical

pollution control equipment, including, but not limited to, deck drains,

sumps, drip pans, and sewage treatment facUities. A l i s t of the typical

mud additives is enclosed in order to conform to the non-pollution

requirements of CCS Order No. 7. Attached is a schematic description of

the blowout prevention equipment and diverter system to be utilized fbr

well control during tiie subject exploratory program. The pressure

BBHS

control system w i l l conform to the requirements mandated in OCS Order No.

'2.

jThe Oil S p i l l Contingency Plan for Marathon Oil Ccmpany was approved on

January 17, 1986. Marathon Cil Ccmpany is a member of the Clean Gulf

Associates. Equipment such as, but not limited to skimmers, booms, and

sprayers could be at t. ie site within twenty-four hours after

notification,

146

• • S I N CANYON

l » 0 - H 140 JL 80 MILES

TO SHORE

7

BLK. 145

m u e nf ORMATWI

ARATHON OIL CO.

OCS. - G - 34$$

4 4

56

VICINITY PLAT

fc •0 00 »T

S C * L l

PROPOSED MINERAL DEVELOPMENT SOUTH MARSH ISL. AREA

G U L F OF M E X I C O

APPLICATION BY A P R I L 14, 1987

MARATHON OIL COMPANY LAFAYETTE, L A .

i r t '

TYPICAL JACK-UP RIG 8 APPURTENANCES

PROPOSED MINERAL DEVELOPMENT

SOUTH MARSH ISL. AREA GULF OF MEXICO

APPLICATION BY MARATHON OIL CO. APRIL 14.1987 LAFAYETTE, LA.

TYPICAL BLQMUT PREVENTER STACK ARRANGEMENT

i_ r

TYPICAL JACK-UP DWERTTR SYSTt*

OOP MANirOI.D

_ I~ -_L • f_L J PJPE | I BUND I I yen

I W O i t l 4 IOO # P S I -

RURRER HOSES

IWO ( 2 | f " AIR OPERAIEO VALVES

ARC CONNECtED SO I I I A f WHEN IME

ItVDRIL 19 CLOSER ROf l l VAI VES

WILI. OPEN, f l l EN E l f HER VALVE

CAN RE CLOSED INDEPENDENTLY OT

EACH Of HER

1>3Z • " P I P E RUNNINO TO EACH SRJC Of PI Af r o f l M

MANUALLY OPERAIED RUI f ERELV VALVE t H A I SIAVS OPENFH A t A I L I IMF 9 r * r r » t W M * M n i v r n i I M O n n w i n w i K W i n w i i r o r P i A i r o N M .

WATER BASE MID CCMPONENTS

GULF OF MEXICO

f ategory

Gelling Agent

Weight Material

Thinner

Viscosifier

Lost Circulation Material

Corrosion Inhibitor

pH Control

Lubricants

Composition

Wyoming Bentonite Clay Attapulgite

Barium Sulfate Barite

Sodium Acid Pyrophosphate Leanardite Phosphate Lignite Resign Soaps Sodium Tetraphosphate Ferrochrome Lignosulfonate Chrome Lignosulfonate Polymeric Lignosulfonate Aluminum Chrome Lignosulfonate Calcium Lignosulfonate Hemlock Bark Extract Gilsonite Quebracho

Starch Carboxymethyl Cellulose Sodium Hexametaphosphate Pelletized Asbestos

Cellophane Mica Flakes Ground Nut Hulls Expanded Perlite Diatomaceous Earth Shredded Leather Rice Hulls

Filming Amine

Potassium Hydrate Caustic Soda

Detergent Castor Oil Alcohol

Various Chemicals CaCl2

CaCo3

»

OIL BASE MJJD COMPONENTS

j . GULF OF MEXICO

Category

Gelling Agent

Weighting Agent

Thinner or Emulsifer

Water Loss Control Agent

pH Control

Lost Circulation Material

Composition

Organophylic Clay

Barite or Barium Sulfate

Organic Fatty Acid Amines

Modified Asphattine

Lime

Cellopliane Mica Flakes Ground Nut Hulls Expanded Perlite Diatomaceous Earth Shredded Leather Rice Hulls

Various Chemicals Oil Diesel CaCl 2

ENVIRONMENTAL REPORT

FOR COASTAL ZONE MANAGEMENT

CONSISTENCY CERTIFICATION

PLAN OF EXPLORATION

SOUTH MARSH ISLAND BLOCK 145

OCS-G-5466

MARATHON OIL COMPANY

P. 0. Box 53266 OCS

Lafayette, LA 70505-3266

Contact Person: Mel Mouton

P. 0. Box 53266 OCS Lafayette, LA 70,505-3266 (318) 233-8240 Ext. 2380

Environmental Report Prepared 4/24/87

TABLE OF CONTENTS

PAGE I . DESCRIPTION OF THE PROPOSED ACTIVITY ~~T~

r A. Transportation Modes, Routes and Supoort Vessels 1

B. Suppor t Base 3

C. New Support Fac i l i t i es 3

D. New or Unusual Technologies 3

E. Maps (V ic in i ty Map, page 2) 4

I I . DESCRIPTION OF THE AFFECTED ENVIRONMENT AND IMPACTS 5

A. Physical and Environmental 5

1. rommerldal Fisheries 5

2. Shipping 6

3. Recreation 7

4. Cultural Resources 7

5. Ecologically Sensitive Features 7-8

6. Existing Pipelines and Cables 9

7. Other Mineral Uses 9

8. Ocean Dumping Grounds 9

9. Endangered or Threatened Species 9-12

B. Socio-economic 12

I I I . UNAVOIDABLE ADVERSE IMPACTS 13-14

IV. REFERENCES 15

V. APPENDIX 16

Coastal Zone Management Consistency Cer t i f i ca t ion 17

I . DESCRIPTION OF THE PROPOSED ACTIVITY

Marathon Oil Company proposes to d r i l l f i ve (5) exploration wells as part of

t he i r Planfof Exploration for South Marsh Island Block 145, South Addition,

OCS-G-546SJ The approximate location of these ac t i v i t i es 1s eighty (80)

statute miles o f f the Louisiana Coast near Iberia Parish. (See map No. 1 ,

V i c i n i t y P a t . )

The proposed a c t i v i t i e s w i l l be carr ied out and completed with the guarantee of

the following Items:

1 . The best available and safest technologies w i l l be u t i l i zed throughout

the pro ject . This Includes meeting a l l applicable requirements for

equipment types, general project layout, safety systems, and equipment

and monitoring systems.

2. All operations w i l l be covered by a USMMS-approved o i l sp i l l

contingency plan.

3. All applicable Federal, State and local requirements regarding a i r

emissions and water qual i ty and discharge for the proposed a c t i v i t i e s ,

as well as any other permit condit ions, w i l l be complied wi th .

A. Transportation Modes, Routes and Support Vessels

The proposed project w i l l u t i l i z e the Berwick Shorebase for supplies and

log is t ics . Support vessels w i l l Include one work /u t i l i t y boat making f ive

t r ips per week to the r ig and one crew boat making two t r ips per week.

Aviation support w i l l require one helicopter making ten t r i ps per week.

The Berwick Shorebase and PHI's Anel la, Louisiana aviat ion base w i l l share

1n helicopter t r i p s with most aviat ion support handled by PHI at Amelia,

Louisiana.

-1-

• W I N CANTON

•ANOIN BANKS V I C I N I T Y MAP o so i oo ito MI.

146

140 eo MILES TO SHORE

7

BLK. 145

MARATHON OIL CO.

O.C.S. - 6-34 66

144

56

VICINITY PLAT

h woo •ooo r t

S C A L E

- 2 -

PROPOSED MINERAL DEVELOPMENT SOUTH MARSH ISL. AREA

G U L F Of M E X I C O

APPLICATION BY APRIL 14, 1987

MARATHON OIL COMPA LAFAYETTE, L A .

1

Bqat t r a f f i c to the r i g w i l l depart Berwick via the Lower Atchafalaya River

southward to the Atchafalaya Bay eni;ance to the Gulf of Mexico, fol lowing

the mdst d i rect route to South Marsh Island Block 145. Helicopter f l i g h t

f routes wi l l Include FAA specified clearance and most d i rect YFR, IFR f l i g h t

paths jto the r i g .

B. Support Base

The Marathon 011 Company maintains a support f a c i l i t y 1n Berwick,

Louisiana. This f a c i l i t y 1s designed to provide shore-base operations

support to the production, d r i l l i n g and marine equipment operating 1n the

Western Sector of the Gulf of Mexico. Subsequently, a l l necessary support

functions for the proposed ac t i v i t y w i l l be provided by th is f a c i l i t y .

The Marathon Oil Company f a c i l i t y 1s currently manned at an adequate level

to support the proposed f a c i l i t y . Therefore, no additional onshore

employment w i l l be generated as a resul t of th is act ion.

C. New Support F a c i l i t i e s

I t has been determined 1n the Plan of Exploration that the exist ing support

f a c i l i t i e s are adequate at th is time to service the level of ac t i v i t y

projected as a resu l t of th is pro ject . Therefore, no new support

f a c i l i t i e s are required.

D. New or Unusual Technologies

No new techniques or unusual technology w i l l be u t i l i zed that may af fect

coastal waters.

- 3 -

Maps

One map Is Included In this report on page 2. The v i c i n i t y map shows the

general locat ion of the proposed project In re la t ion to the affected

State's coastal zone. This map also contains a location plot Indicating

the surface locations of a l l f i ve (5) proposed exploration wel ls.

»

I I . DESCRIPTION OF THE AFFECTED ENVIRONMENT AND IMPACTS

This sectlcjn w i l l address the effects of the proposed ac t i v i t y on the areas

i adjacent to the s i te and the affected State's coastal zone.

A. Physical and Environmental

1 . Commercial Fisheries

Louisiana ranks among t e top f i ve states 1n the nation with regard to the

total value of I t s f i sh ing. For the last several years, Louisiana has been

the number one state 1n weight of f ishery products landed.

The shrimp f ishery 1s the most valuable f ishery 1n Louisiana as well as the

United States. In terms of harvested weight, however, the Gulf Menhaden is

by far the largest contributor to the total commercial landings 1n

Louisiana.

In 1980, Louisiana led a l l states 1n volume of total f isheries landed with

920.1 mi l l ion pounds valued at $138.8 m i l l i on . During the same year, the

Louisiana shrimp landings to ta l led 104 mi l l i on pounds valued at $87.2

mi l l ion . The Gulf States accounted for over half of the U.S. shrimp

production.

The proposed pro ject 1s located In the National Marine Service f ishing zone

15; water depths 1n th is area vary from approximately 230-242 feet. In

this grid zone, Menhaden account for approximately 90* of the total

commerlclal landings by weight. Shrimp account for approximately 8% of the

total catch.

-5 -

The major potential Impacts of the proposed activity on commercial

fisheries are:

aj. Loss of approximately five hectares of seafloor from use by

trawlers. However, this should not be a problem due to water

| depth. Installations like drilling rigs and platforms actually

take up very little sea space; but to protect th .i, operators are

permitted to establish a safety zone around them, generally one

quarter nautical mile 1n radius.

The Impacts associated with the proposed activity are considered minimal.

These impacts are otherwise offset by the beneficial increase 1n biomass

near the rig. These structures attract a variety of animal and plait life

and contribute to Increased productivity In these areas.

2. Shipping

Morgan City, Louisiana 1s the nearest port to the proposed activity.

Hydrocarbons, fuels, chemicals, and petroleum products are the major

commodities shippped from and to Morgan City via the Lower Atchafalaya

River.

South Marsh Island Block 145 1s approximately 22 statute miles north of the

nearest shipping fairway. Thus, the proposed activity 1s not expected to

affect any shipping fairway. South Marsh Island Block 145 1s not located

1n or near an anchorage area; therefore, the five well surface locations

are not expected to affect any anchorage area.

-6-

3.. Recreation

Many fish and shell f ish sought a f ter for commercial value are also pursued

fjar sport 1n coastal Louisiana. Saltwater sport species Include spotted

a t rout , red drum, red snapper, Florida pompano and tarpon. The offshore

rmanent structures provide highly productive a r t i f i c i a l reefs that are

favorable f ish ing areas for saltwater sport fishermen. Addit ional ly, these

offshore structures serve as navigational aids for small boat operators and

occasionally provide shelter and refuge during storms and mechanical

breakdowns. Thus, the Implementation of th is project 1s not expected to

produce any adverse impacts on sport f ishing and pleasure boating; 1n fac t ,

recreational potent ial w i l l be s l i gh t l y Increased due to th is act ion.

4. Cultural Resources

The results of an underwater High Resolution Geophysical survey conducted

by Alpine Ocean Geophysics In January 1986, Indicates sur f i c ia l sediments

as s i l t y c lays. Visual #2 MMS Environmental Impact Statement Indicates

sediments to be Pleistocene marine shelf deposits on the axis of the

PHo-Pleistocene production t rend. South Marsh Island Block 145 1s

approximately ten (10) miles south of the Historic Cultural Resources High

Probability l i n e and should not Impact any known cultural or archaeological

resources.

5. Ecologically Sensitive Features

The proposed pro ject 1s located approximately 80 miles offshore from the

Iberia Parish, Louisiana. This coastal area 1s characterized by numerous

acres of marsh which provide habitat for a variety of w i l d l i f e and also

serve as primary nursing grounds for f ish and she l l f i sh .

- 7 .

The Shell Keys National Wi ld l i f e Refuge (50 acres) and the Marsh Island

Wildl i fe Refuge (86,000 acres) serve many conservation/preservation

functions 1n w i l d l i f e management. The proposed project is located

approximately 80 miles south of these b io log ica l ly sensitive areas.

The Rockefeller Wi ld l i fe Refuge (84,000 acres), a Louisiana State w i l d l i f e

area, is located approximately 100 miles northwest of the proposed ac t i v i t y

s i te . This areas is delineated as an area of peak duck concentrations.

Geese concentrations also occur in and around the refuge. Of special

importance 1s the resident population of about 2,000 Canadian Geese who

decline in recent years in th is area is due to changes in migratory

patterns (Louisiana State Planning Off ice 1984).

The proposed ac t i v i t i es associated with th is project are not expected to

produce any adverse impacts on the coastal environment or any protected

wi ld l i fe refuge. Furthermore, there are no ecological ly sensitive area or

^reas of par t icu lar concern in or near South Marsh Island Block 145 which

would be adversely or otherwise affected by the proposed action. Fishnet

Bank 1s the nearest ecological ly sensit ive area and Is approximately 20

miles southeast of Block 145.

The nearest recreational beaches occur along the Louisiana coast. Holly

Beach, Louisiana Is northwest of the project area and is approximately 125

miles from the proposed act ion. No d i rect impacts on the recreational

potential of these areas are expected as a resul t of th is act ion.

-8 -

6. Existing Pipelines and Cables

Results of a High Resolution Geophysical Survey conducted in January 1986

\ indicates a 16" pipeline leaving Mesa/Oxy Block 156 "A" platform traverses

Block 145 from the center of the south l ine of the block to about one-third

| south along the east l ine of Block 145.

Twenty-two magnetic anomalies were detected within the Block. Thirteen are

related to the pipeline and six to previous d r i l l i n g ac t i v i t y . There are

no known cables in the Block which would obstruct or hinder the proposed

project.

7 . Other Mineral Uses

There are no known plans to produce other minerals other than those

hydrocarbons associated with the proposed ac t i v i t y in South Marsh Island

Block 145.

8. Ocean Dumping Grounds

Ocean dumping is prohibited 1n South Marsh Island Block 145. The nearest

E.P.A. approved ocean dumping s i te 1s approximately 120 miles southwest of

the ac t i v i t y s i te (USDI, OCS Sale 104/105, Visual #11).

9. Endangered or Threatened Species

The proposed project located 80 miles o f f the Iberia Parish, Louisiana

coast 1s wi th in the range of f ive endangered species of whales, three

species of endangered t u r t l e s . Onshore the Iberia Parish area 1s within

the range of the endangered bald eagle and American a l l i ga to r .

-9-

a. Whales (Endangered)

- Sel whale (Balaenoptera borealis) This species Is a possible

j winter resident of the Gulf of Mexico.

- Fin whale (Balaenoptera phy.i lus) This species 1s a possible

| winter resident of the Gulf of Mexico.

- Blue whale (Balaeno ptera muse ulus) This species is uncommon to

the Gulf of Mexico.

- Humpback whale (Megaptera novaeangliae) This species is a

possible winter resident of the Gulf of Mexico.

- Sperm whale (Physeter catodon) The most common of the

endangered whales to occur 1n the Gulf of Mexico.

Migratory patterns of the whales l i s ted above are not d i rec t ly known. I t

1s presumed, however, that these species occur mainly 1n the deeper waters

of the Gulf o f Mexico. Therefore, the proposed project is not expected to

adversely a f fec t whale populations or migratory patterns.

b. Turt les (Endangered and Threatened)

- Kemp's At lant ic r id ley (Lepidochelys kempii) The shrimping

grounds of the northern Gulf of Mexico 1s a primary feeding area

for th is endangered species.

- Hawksbill t u r t l e (Eretmochelys imbricata) An endangered species

that may occur In the coastal waters of Louisiana.

- Leatherback t u r t l e (Dermochelys coriacea) The range of th is

endangered species is usually the deeper waters of the Gulf of

Mexico; however, observations have been made of large numbers of

leatherb*cks feeding on j e l l y f i s h In Inshore waters during

summer (USDI, EIS, OCS Sale 104/105, page 229).

-10-

- Green tu r t l e (Chelonia mydas) and the Loggerhead t u r t l e (Caretta

caretta) are l i s t e d as threatened and occur In the Gulf of

Mexico waters.

Thejre are no known t u r t l e nesting areas near the proposed project s i t e .

Therefore, no measurable d i rec t impact on the tu r t les l i s ted above 1s

expected to occur as a resu l t of the proposed ac t i v i t y ,

c. Onshore Spe, es (Endangered)

- Bald eagle (Hal 1aeetus 1eucocephalus) In the Southeast United

States, bald eagles act ively nest In South Carolina, F lor ida,

Mississippi , Louisiana and Texas. There were forty-one reported

act ive nests In Loulsi.:** during the 1986 nesting season,

feeding ac t i v i t i e s of baifi eagles in the central and western

Gulf States are restr ic ted *o Inland areas there are no expected

Impacts associated with the proposed project . (U.S. Fish and

Wi ld l i f e Service, Jackson, Mississippi ; D i s t r i c t Office Report).

- American A l l iga to r (A l l iga tor mississippiensis) This species 1s

current ly c lass i f ied as an endangered species In the coastal

areas of Louisiana. Subsequently, twelve parishes current ly are

allowed to permit regulated harvests of a l l igators in the i r

respective parishes; Iberia Parish Is one of these. ? *e laws

govern the harvests and allow the taking of a l l l ga tc * hides and

meat during established harvest seasons.

located pr imar i ly in the ••* Since most of the

-11-

1

The American Al l igator is the only species current ly on the federal l i s t of

endangered or threatened species that Is commonly found 1n the coastal

areijs near the project. J

Thejproposed project does not require any additional onshore f a c i l i t i e s ;

therefore, there are no expected impacts on the habitat of these

onshore-endangered or threatened species as a resul t of th is act ion.

B. Socio-economic

Not applicable at th is time.

-12-

I I I . UNAVOIDABLE ADVERSE IMPACTS

The environmental consequences of the proposed project are expected to be 4

minimal. Most Impacts ident i f ied w i l l be of a temporary nature and w i l l

occur! in the Immediate v i c in i t y of the operation. Therefore, no long term

effect on the environment 1s expected.

Unavoidable adverse impacts include:

1. An Increase 1n a i r pol lutants as a resul t of power generation, during

d r i l l i n g and transportation modes. However, an a i r quali ty review has

been conducted pursuant to 30 CFR 250.57, the findings of th is review

indicate that the projected emissions are well below the exemption

rates and pose no s ign i f icant impact on the ambient a i r qual i ty of the

onshore environment.

2. A temporary reduction in water qual i ty due to the disposal of d r i l l

cut t ings, deck drainage, sanitary and domestic waste w i l l occur as a

resul t o f th is action. During the disposal of d r i l l cut t ings, an

increase 1n turb id i ty w i l l be evident as a resul t of d r i l l i n g f lu ids

adhering to these par t i c les . Since the ava i l ab i l i t y of sunlight 1s an

Important factor 1n photosynthesis, i t has been found that Increased

tu rb id i t y reduces photosynthesis. However, th is e i fec t w i l l be

short-term and w i l l return to normal once the d r i l l i n g phase is

completed. The additional sources of water pol lutants are also

expected to produce minimal and short-term ef fects on the water quali ty

near the r i g . These pol lutants are regulated by the U.S. Environmental

Protection Agency's e f f luent guidelines under the National Pollutant

Discharge Elimination System (NPDES) General Permit GMG282054 for o i l

and gas extract ion.

-13-

Conformance to these guidelines wi l l be carried out throughout the

project•per iod.

i

3. Burial ojf the immobile benthic organisms w i l l occur during the

discharge of d r i l l cut t ings. D r i l l cutt ings accumulate on the sea

f loor covering an area of approximately 150 feet in diameter; in the

a'feeted area the impact 1s localized and dissipates over time by

currents. Mobile benthic organisms from the surrounding sea f loor

adjust rather rapidly to these changes and bui ld homes on top of the

cut t ings. Within months the affected area is again f lourishing with

new benthic communities (Zingula et a l , 1977). Thus, the impacts

associated with this ac t i v i t y 1s short-term and local ized.

4. There w i l l be a loss of approximately twelve acres (5 hectares) of sea

space that w i l l be unavoidable for commercial f i sh ing . I f the wells

are economically producible then eventual future development/product!on

operations would have a more permanent e f fec t . However, there are some

positive external i t ies assoicated with the proposed ac t i v i t i es that

would, 1n the long run, benef i t commercial and recreational f i sh ing ;

these are:

- An increase in biomass near the r i g , thus, result ing 1n higher

product iv i ty ,

- Offshore structures may serve as navigation aids and during

mechanical breakdowns or inclement weather provide for a refuge

fo r boat operators.

-14-

REFERENCES

Buck, D. H. "Ef fects of Turbidity on F1sh and Fishing". North American { Wi ld l i fe Conference 21: 249-261. f Burke and Associates, Inc. Unique Ecological Features of the Louisiana Coast I prepared for Louisiana State Planning orr ice: Baton Rouge, Louisiana, 19 / / .

Gowanlock, James Nelson. Fishes and Fishing in Louisiana. C la i to r 's Book Store Press: Baton Rouge, Louisiana, i9b»>.

Hay Keith, "Fishing and OCS Energy Development/Charting a Course of Compatibility" Coastal Zone '80 Proceedings of the Second Symposium on Coastal and Ocean Management, 1980.

Lowery, G. H., J r . The Mammals of Louisiana and I ts Adjacent Waters. Louisiana University Press, Baton Rouge, Louisiana, 1974.

Renner, James R. The Coastal Zone: An Overview of Economic, Recreational and Demographic Patterns. Baton Rouge: Louisiana State Planning Of f ice , 197b.

United States Department of Commerce, National Oceanic ar.d Atmospheric Administration. Final Env 1 ronmen1 taiT Impact Statement for the Louisiana Coastal Resources Program, Office of cr ista t zone^rfi^ement,' flashing ton , TJX r rWOT " " " "

United States Department of I n te r io r , Minerals Management Service. Regional Environmental Impact Statement; Final Proposed 1982 Outer Continental She i f 011 and Gas Lease Sales 72/74 "and 79. Gulf of Mexico, Volume 1 and 2. Washington, D . C , 1983.

United States Department of the In te r i o r , Minerals Management Service. Draft Environmental Impact Statement; OCS Sales 104/105. Proposed 1986 Outer Continental Shelf 011 and Gas Lease Sales 104/105: Gulf of Mexico, Washington, D .C , 1985.

United States Department of the In te r io r , U.S. Geological Survey. Compilation o f Regulations Related to Mineral Resource Ac t iv i t ies on the Outer Continental Shelf: volume l and z. Washington, D.C, 1981.

United States Department of the In te r i o r , F1sh and Wi ld l i fe Service; Region 4 Endangered Species Notebook. At lanta, Georgia, 1979.

Zingula, Richard P. and Larson, Dana W. "Fate of D r i l l Cuttings 1n the Marine Environment" Offshore Technology Conference, 1977.

APPENDIX

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COASTAL ZONE MANAGEMENT

CONSISTENCY CERTIFICATION

Plan of Exploration

Type of plan

South Marsh Island Block 145

Area and Block

OCS-G-5466

Lease Number

The proposed a c t i v i t i e s described in detail in th is Plan comply with Louisiana's approved Coastal Management KIogr',nis) and w i l l be conducted in ; "manner consistent w i th such Pro<,."am( s) .

Arrangements have been made with the State-rimes in Baton Rouge, Louisiana, to publish a public notice of the p-oposed ac t i v i t i es no la te r than May 14, 1987.

Marathon Oil Conpai.y

Lessee or Operator

Cert i fy ing Of f ic ia l

Date

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MARATHON OIL COMPANY

SOUTH MARSH ISLAND BLOCK 145 (OCS-G-5466)

PROJECTED EMISSIONS FROM EXPLORATION OPERATIONS FOR COMPLIANCE PURSUANT TO 30 CFR 250.57

AIR OUALITY REGULATIONS

I . General Tnformation

Operation Description: Owner/Operator: Address:

Location of Fac i l I t y :

Operation Begin: End:

Schedule:

Exploration Marathon 011 Company P. 0. Box 53266 OCS Lafayette, Louisiana 70505-3266 South Marsh Island Block 145 OCS-G-5466

Drfl ' i ing July 1 , 1987 December 31, 1988

Distance to Shoreline (mean high water l eve l ) : Eighty (80) statute miles

I I . Synopsis

The projected emissions derived as a result of this revie* reprevsnt a maximum ( l i b e r a l ) assessment for indicator pol lutants. The findings of this assessment indicate that the proposed emissions herein are well below exemption rates and pose no s ign i f i cant impact on the ambient a i r qual i ty of the onshore environment. Based on tMs assessment, no further a i r quality review is required.

I I I . Projected Emisssions

Rig Projected Emissions

1987 1988 Exemption Rate Exemption Pollutant Tons/Period1 Tons/Year Tons/Year Status

CO 15.57 30.01 63,125.6 Exempt SO? 1.76 3.01 2,664.0 Exempt N0X 97.67 187.78 2,664.0 Exempt YOC 4.90 9.54 2,664.0 Exempt TSP .57 .95 2,664.0 Exempt

1. Based on a 6 month d r i l l i n g period with 30,000 feet d r i l l e d .

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III . (cpntinued)

Service Based Projected Emissions

Pollutant

1987 Berwick, Louisiana

Tons/Period 1

1988 Berwick, Louisiana

Tons/Year

11.79 .05

23.58 .10

72.47 4.04

144.94 8.09

TSP .07 .14

1. Based on a 6 month d r i l l i n g period.

IV. Exemption Formula

The projected emissions from operations are to be compared with "exemption rules" for the f a c i l i t y locat ion. I f the amount of these projected emissions Is less than or equal to the emission amount "E" for each a i r pol lutant, the f a c i l i t y 1s exempt from further a i r quali ty review.

The fol lowing formulas pursuant to 30 CFR Part 250 Sec. 250.57-1(d) are used to determine exemption rates:

For CO: E « 3400 D*/3 For TSP, S02, N0X, VOC: E = 33.30 D • distance of the f a c i l i t y in statute miles from the closest onshore

Based upon these exemption formulas the following emission rates were computed for South Marsh Island Block 145. Distance from nearest onshore j»*ea 1* >iqhty (P-O) statute mi les.

V. Methodology

D r i l l i n g : Horsepower/Hour Method (Power generation 1 actor 60 HP-HR/ft.,

area.

Pollutant Exception Rate

Tons/Year

CO 63,125.6 2,664.0 2,664.0 2,664.0 2,664.0

Reference # l -pg. 86)

Transportation Modes:

Boats: Horsepower/Hour Method - Reference #2 Helicopters: Landing/Take Off (LTO)

Cycle Method - Reference #2

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V I . References

1. EPA-450/3-77-026 June, 1977 - "Atmospheric Emissions from Offshore 011 ar.d Gas Development and Production" pp. 81-92.

2. d*A Report AP-42 "Compilation of A1r Pollutant Emission Factors", 3rd Edit ion (August, 1977) pp. 116, 125, 127.

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EXHIBIT A

Emisssion Factors Used in Calculation

J Emission Factors for Pril l ing

Pollutant lb/hp-hr

CO .0042 SO2 -0019 M0X .028 YOC .00095 TSP .00053 (estimated)

Emission Factors for Transportation Modes

Helicopters Boats Pollutant lb/eng ine LTO Cycle lb/gal

CO 5.7 .0598 SO? * NOv .57 .4196 VOC .52 .0226 TSP .25 *

* Not available from EPA publication

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EXHIBIT B

Miscellaneous Information

D r i l l i n g : Total Well Footage tc be Dr i l l ed : South Marsh Island 145 - 81,000 feet

Supply Boats - D r i l l i n g :

3000 Hp 5 Tr ips Per Week 12 Hours Waiting Time Base - Berwick, Louisiana

Crew Boats - D r i l l i ng :

250O Hp 2 Tr ips Per Week 1 Hour Waiting Time Base - Berwick, Lousiana

Hel icopters - D r i l l i n g :

2 Engines 10 Tr ips Per Week Base - Berwick an'i Amelia, Louisiana

Operations Schedule:

D r i l l i n g : Begin: July 1, 1987 End: December 31, 1988

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