Summary: Chevron USA's Destin Dome 56 Unit Development & Production Plan

U.S. Department of the Interior
Minerals Management Service
Gulf of Mexico OCS Region

FOR RELEASE:	October 2, 1997

Summary: Chevron USA's Destin Dome 56 Unit
Development & Production Plan

General Information

The DD Unit consists of 11 blocks. Five of the 11 blocks were leased in 1984. Three more were leased in 1985, and the remaining 3 were leased in 1989.
Chevron, Murphy Exploration and Production Company, and Conoco Inc. each own one-third interest in the Unit.
Three exploratory wells have been drilled so far which confirm the presence of large quantities of natural gas. No other forms of hydrocarbons have been encountered so far at any depths in these three wells.
Up to 12 wells with production up to 300 MMCFD is the "expected" scenario. Up to 21 wells with production up to 450 MMCFD would be the "maximum" scenario. Up to 20 new wells may be drilled. One existing well (57#1) would be completed and put on production.
Two jack-up drilling rigs would be utilized operating concurrently during the drilling phase of development.
Gas will be routed to a central processing facility (CPF), moved by pipelines in Federal waters to an area off the coast of Mobile, AL, and sent to shore through existing or proposed third party lines to existing gas plants in Mobile County, AL.
Boat and helicopter support will use existing shorebases in Pascagoula, MS or Theodore, AL.
Water depths in the 11-block unit range from about 100-500 ft. The depths where wells will be drilled range from 105-252 ft.
The seafloor is mostly smooth sand or undulating with hummocks, swales, and ridges. Seafloor sediments are predominately medium to coarse quartz sand and shell hash. Some irregular hard-bottom features also occur. The most significant hard-bottom feature is a ridge which trends through Blocks 99, 56, and 57. Other features are found in blocks 55 and 100.
The target is the Jurassic Norphlet Formation. Within the 11-block unit, the top of this formation occurs from -21,500 to -25,000 ft. subsea. A typical well would be drilled to a depth of +/-24,000 ft.

Pipelines

Flowline bundles - A flowline bundle will run from each satellite to the CPF. Each bundle will consist of the following pipelines:
- 1- 6", 8", 10", or 12" flowline carrying produced gas from the satellite to the CPF
- 1- 3" pipeline carrying corrosion inhibiting solvent from the CPF to the satellite
- 1- 2" fuel gas pipeline carrying fuel gas from the CPF to the satellite
Combined Production Line Bundles - A combined production line bundle will be run from each header platform to the CPF. Each bundle will consist of the following pipelines:
- 1 - 16" flowline carrying gas from the header platform to the CPF
- 1 - 4" CIS pipeline carrying CIS from the CPF to the Header Platform
- 1 - 3" fuel gas pipeline carrying fuel gas from the CPF to the header platform
Export Pipeline - One 30" export pipeline will run from the CPF at Destin Dome Block 12 to Unocal's Platform at Mobile Block 916.
Connecting pipelines will be run as required from Mobile Block 916 to Shell's Block 113 Platform, Mobil's Block 823 Platform, Exxon's 112 Platform, or Chevron's Block 864 Platform where they will tie into existing pipelines carrying the gas to shore.

Platforms

The plan will involve three types of platforms--Satellite Well Platforms, Central Production Platform(s), and a Bunkhouse Platform.
The "maximum" development case will consist of:
- 10- single-well satellites
- 4- two-well satellites
- 2- eight-pile CPF's (Block 12)
- 1- three-well satellite
- 1- bunkhouse platform
Satellites - Satellite platforms would be installed at each well surface location. Gas from the well bore would be routed to treating facilities on the satellite platform.
- Satellite platform deck dimensions will be about 80' x 80'.
- The platform for the CPF(s) will be about 180' x 90'.

Corrosion Inhibiting Solvents (CIS)

CIS is injected into the gas stream between the choke and static mixer to:

protect against diamondoid deposition and elemental sulfur deposition downstream of the choke
provide corrosion protection for the carbon steel piping downstream of the Production Cooler.

CIS would be transported to the CPF's by crewboats in 100 BBL DOT certified transporter containers. Onshore Support Base(s)

The onshore support base for drilling and production will be an existing base located on the Theodore Ship Channel in Mobile County, Alabama or on Bayou Cassotte in Pascagoula, Mississippi.
It is not anticipated that expansion of any onshore support base will be necessary to support development of the Destin Dome Unit. Possible onshore bases are:
- Midstream Fuel Services, Inc., Exxon Shorebase Facility, or Liberty Services Inc. (Theodore Ship Channel)
- Midstream Fuel Services, Inc. (Bayou Cassotte)

October 2, 1997

Important Milestones in the EIS Process

August 1997 - Notice of Intent published in Federal Register
October 1997 - public scoping meetings
November 1997 - scoping report distributed
August 1998 - draft EIS filed with the U.S. Environmental Protection Agency (EPA)
September 1998 - public hearings on draft EIS
October 1998 - end of 60-day comment period on draft EIS
May 1999 - final EIS filed with the EPA
June 1999 - end of 30-day comment period on final EIS
August 1999 - decision made on permit

[Note: The dates above represent the best estimate of the MMS at this point in the process. All dates are subject to change.]

Opportunities for Public Input Into the EIS Process

The Notice of Intent to prepare an environmental impact statement (EIS) was published in the Federal Register on August 22, 1997.
The 45-day comment period for the Notice of Intent closed on October 6, 1997.
Scoping meetings are being held from October 7 to October 17, 1997 to receive public input early in the EIS process.
Written scoping comments will be accepted through October 31, 1997.
Comments received during the scoping process will be considered during preparation of the draft EIS.
The draft EIS is scheduled to be distributed to interested parties in August 1998.
A 60-day comment period will be allotted for comments on the draft EIS.
Public hearings on the draft eis are scheduled to be held in late-September/early- October 1998.
The comment period for the draft EIS ends in October 1998.
Written comments on the draft EIS and comments received at the public hearings will be addressed in the final EIS.
A 30-day comment period will be allotted for comments on the final EIS.
August 1999 - decision made on permit

-MMS-GOM-

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