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Two Bass Strait concrete units mark progress

Nov. 4, 1996

Esso Australia Ltd./BHP Petroleum Pty. Ltd.'s Bream B concrete platform has been successfully positioned in Bass Strait following a 7-day tow from Port Kembla shipyard south of Sydney. The platform, smaller of two concrete structures built at Port Kembla the last 4 years, is a first for Australia and a first for Esso parent Exxon Corp. as an operator. It was towed to location as a complete commissioned unit.

Esso Australia Ltd./BHP Petroleum Pty. Ltd.'s Bream B concrete platform has been successfully positioned in Bass Strait following a 7-day tow from Port Kembla shipyard south of Sydney.

The platform, smaller of two concrete structures built at Port Kembla the last 4 years, is a first for Australia and a first for Esso parent Exxon Corp. as an operator. It was towed to location as a complete commissioned unit.

The 55 m wide, 45,000 metric ton Bream B structure is to be an unmanned satellite platform remote operated via umbilicals from Bream A platform about 6 km away. Bream B has conductor slots for 18 wells. Oil will be sent directly from the wellheads by pipeline to Bream A for processing and export via pipeline to shore.

Bream B's sister platform at Port Kembla is West Tuna, destined to be the largest structure placed in Bass Strait. Weighing 104,000 tons, West Tuna will be floated out of the harbor and towed to Tuna field early this month.

West Tuna has conductor slots for 48 wells, some of which will be dual completions. The platform will have facilities to handle both high and low-pressure hydrocarbons expected from complex, subsea lenticular reservoirs.

The concrete gravity base design, with accompanying shore-based topside module lifts, was chosen to obviate a need for costly derrick barges offshore.

The two platforms in the $1.1 billion (Australian) development project will produce a total of about 108 million bbl of oil and 75 bcf of gas in a 20-30 year period. Production in 1997 is expected to reach about 30,000 b/d of oil, or about 15% of current Bass Strait production.

First production from Bream B is expected in December and from West Tuna early in 1997. The two platforms increase the number of platforms in Bass Strait to 18.

Meantime, the concrete gravity base section for Ampolex's Wandoo oil field off Western Australia has been towed to its field location. However, unlike the Bass Strait program, the topside modules for Wandoo have yet to be lifted into place.