Woodside Offshore Petroleum Pty. Ltd., Perth, has let contract to Kvaerner AS, Oslo, and Single Buoy Moorings Inc. (SBM), Marly, Switzerland, to help build what it claims will be the world's largest production barge for installation in the Timor Sea in a $1 billion (Australian) project.
The $420 million turnkey contract calls for construction of topsides and mooring system for a vessel to be installed as part of field development of Laminaria and Corallina discoveries in the Timor Sea off Northwest Australia, where water depth is about 365 m.
Laminaria and Corallina lie about 9 km apart on Block AC/P8, and they will be developed with subsea facilities in the fields tied back to the shared oil production barge.
Elsewhere off northern Australia, Woodside let a $3 million (Australian) contract to a combine of Brown & Root Engineering and J.P. Kenny Ltd. for design and project management of a proposed second trunk gas pipeline to link its gas platforms to production facilities on Western Australia's Burrup Peninsula.
This puts the combine in the running for the full $500 million (Australian) contract for construction project management if the pipeline proposal gets a green light.
Laminaria/Corallina
Laminaria was discovered in October 1994. Wood Mackenzie Consultants Ltd., Edinburgh, has estimated its total potential reserves at 150-200 million bbl of oil, dependent on further appraisal of the field's northern sector.
Woodside pegged reserves at 125 million bbl of oil in Laminaria's central and southern areas. Wood Mackenzie has also estimated Corallina reserves at 50-100 million bbl of oil.
The 1 Laminaria flowed 7,500 b/d of 59 gravity oil on test in 1994. The 2 Laminaria well, drilled in March 1995, flowed 6,600 b/d of 57.5 gravity oil on test.
A third well, 3 Laminaria, was drilled to confirm the field's oil/water contact on the southern flank. This well was sidetracked through the upper interval of the reservoir, said Wood Mackenzie, but no tests were performed.
The 1 Corallina wildcat was completed in January 1996, flowing 7,700 b/d of 60° gravity oil on test.
Production barge
The barge is expected to produce first oil late in 1998 or early in 1999, with production capacity of 170,000 b/d and storage capacity of 1.4 million bbl.
It will be 273 m long, with a breadth of 50 m and a draft of 28 m.
Kvaerner said it will provide the complex topsides for the production barge, while SBM will provide the large-diameter turret mooring and fluid transfer system. Woodside earlier awarded the hull construction contract to South Korea's Samsung Heavy Industries.
The Kvaerner/SBM contract involves design, procurement, fabrication, commissioning, and start-up of the production vessel. It also covers planned and unplanned maintenance during the first 3 years of field operations, with an option for extension for field life.
License partners in the Laminaria/Corallina development are: operator Woodside 50%, Shell Australia Ltd. 25%, and BHP Petroleum Pty. Ltd. 25%.
Development details
Woodside said water depths in Laminaria and Corallina are 360-420 m, making it Australia's deepest offshore field development.
The production barge will be moored between the two finds in 360 m of water. A shuttle tanker will be able to moor in tandem to the barge for crude oil offloading.
Woodside said the development plan calls for a mobile rig to drill and complete six subsea production wells in Laminaria and two production wells in Corallina.
Gas will be reinjected in a dedicated well. Any additional wells will be drilled in clusters and connected back to the barge via flowlines and dynamic risers.
First oil is expected early in 1999, with total capital investment estimated at $790 million (U.S.). Woodside anticipates government approval for its field development plan in March.
The company has also let contract, for an undisclosed sum, to the Perth-based units of Coflexip Stena Offshore SA and J.P. Kenny Ltd. for design of subsea facilities and procurement of long-lead items.
Woodside said the full subsea contract scope will include subsea engineering and project management, including supply of subsea wellhead and completion equipment; supply and installation of flowlines, umbilicals, and risers; towout of the production barge; and installation of the mooring system and risers.
The current largest production barge in the world, a concrete structure, was installed last year in N'kossa field off Congo by field operator Elf Aquitaine (OGJ, Nov. 27, 1995, p. 31).
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