NW SHELF DEVELOPMENT/LPG EXPORT PROJECT OKAYED

Northwest Shelf joint venture partners have given a green light to the $915 million Wanaea/Cossack oil and gas field development and liquid petroleum gas export project off Western Australia. Australia's biggest oil field development in 13 years, the project also received approval from Australia's government last week. Led by Woodside Petroleum Ltd., the joint venture operates the massive Northwest Shelf gas development/liquefied natural gas export project on Western Australia's

Oct. 11, 1993

3 min read

Northwest Shelf joint venture partners have given a green light to the $915 million Wanaea/Cossack oil and gas field development and liquid petroleum gas export project off Western Australia.

Australia's biggest oil field development in 13 years, the project also received approval from Australia's government last week.

Led by Woodside Petroleum Ltd., the joint venture operates the massive Northwest Shelf gas development/liquefied natural gas export project on Western Australia's Burrup Peninsula.

PROJECT DETAILS

The Wanaea/Cossack field project includes converting a crude oil tanker, a 150,000 dwt vessel to be renamed Cossack Pioneer, into a floating production, storage, and offloading (FPSO) unit for installation in Wanaea field.

Cossack wells, in 270 ft of water, will be tied back to the FPSO.

In addition, plans call for construction of an LPG extraction and storage plant on the Burrup Peninsula adjacent to Northwest Shelf gas liquefaction facilities.

Cost of offshore development, including tanker conversion, offshore pipelines, and subsea connections, is estimated at $700 million. The onshore LPG extraction plant, including wharfs and storage tanks, will cost another $215 million.

Reserves are estimated at 200 million bbl in Wanaea field and 33 million bbl in Cossack. Production is expected to peak at 115,000 b/d and 100 MMcfd of gas. The fields are scheduled to go on stream at yearend 1995.

Wanaea gas will move by pipeline 33 km to the Northwest Shelf project's North Rankin A gas/condensate platform, where it will join the gas/liquids stream in the existing trunk line to shore.

Initially the two fields will produce from five Wanaea wells and two Cossack wells. Plans call for later bringing on stream three more Wanaea wells and a third Cossack well.

Wanaea was discovered in 1989, Cossack in 1990.

LPG DECISION

The partners' decision to produce LPG complies with government requests that gas flaring be eliminated from oil and gas projects whenever possible.

Wanaea gas, when combined with liquids-rich gas from nearby Goodwyn field, make the LPG extraction plant viable. LPG production is expected to begin in fourth quarter 1995 and peak at 800,000 metric tons/year.

Onshore work will entail construction of a new LPG/condensate loading wharf adjacent to the existing LNG loading jetty. That will help avoid further congestion of tanker traffic at the LNG berths. Three more LNG cargoes to Spain's Enagas have been approved for delivery this year beyond existing Japanese contracts.

The project go-ahead comes despite a poor economic climate and relatively low oil prices. Northwest Shelf partners predict revenues from Wanaea/Cossack's oil and LPG production will be about $1 billion/year at current prices.

It also comes despite a setback earlier this year for the Woodside group's Goodwyn gas field development project.

Repair of damaged primary piles pinning Goodwyn A platform jacket to the Northwest Shelf seabed restarted in August, 8 months after the damage was discovered during the initial installation phase. Repair cost, projected at $250 million, will involve reforming the piles using mechanical and hydrostatic pressure and specially designed hydraulic and cutting tools. The repair program is expected to take 3-4 months. Work will then continue with insertion of insert piles and placement of topsides.

Goodwyn A now is expected to start production of gas and condensate in October 1994, a year behind the original schedule.

Wanaea/Cossack partners are operator Woodside, BHP Petroleum (Northwest Shelf) Pty. Ltd., BP Developments Australia Ltd., Chevron Asiatic Ltd., Japan Australia LNG (MIMI) Pty. Ltd., and Shell Development (Australia) Pty. Ltd., each with a one-sixth interest.