Watching the World Platform for sale: one careful owner

With David Knott from London [email protected] When Phillips Petroleum Co. U.K. Ltd. conceived the revolutionary Maureen platform in the late 1970s, abandonment seemed a remote problem for the U.K. North Sea. Now, after the Brent spar controversy and rising public concern over environmental issues, reusable Maureen platform still appears futuristic. Block 16/29a Maureen field was discovered in 1973. Total reserves were estimated at more than 200 million bbl of oil.

Aug. 12, 1996

3 min read

When Phillips Petroleum Co. U.K. Ltd. conceived the revolutionary Maureen platform in the late 1970s, abandonment seemed a remote problem for the U.K. North Sea.

Now, after the Brent spar controversy and rising public concern over environmental issues, reusable Maureen platform still appears futuristic.

Block 16/29a Maureen field was discovered in 1973. Total reserves were estimated at more than 200 million bbl of oil.

David Brown, Phillips' exploitation and development manager, said, "There was no infrastructure in place at that time, and reserves were too small to justify a pipeline, hence we decided on a storage platform concept."

Phillips chose the innovative design of Tecnomare SpA, Milan, for a steel gravity base structure standing in 95 m of water.

Tecnomare envisaged a platform that could be refloated for further use on another field once Maureen production had ceased.

The platform incorporates a four-legged jacket within an equilateral triangular base, with an upright steel storage cylinder at each corner. Oil is pumped to an offshore loading column for offtake by shuttle tankers.

Platform details

The platform's three storage tanks can each hold 220,000 bbl of oil. Topsides were designed for 80,000 b/d production, although output peaked at 102,000 b/d in 1984, a year after first oil.

Production is now about 9,000 b/d of oil, and the field will become uneconomic when production falls to 5,000 b/d. This is expected before 2000.

Phillips recently completed studies that confirm the platform can be safely removed from the seabed.

To refloat the platform, water would first be pumped from the topsides to the undersides of the storage tank skirts through existing pipes to loosen the skirts' hold on the seabed.

Then air would be blown into the storage tanks to give them buoyancy: "There would be no surge, and stress levels generated during the refloat can be maintained at acceptable levels with the deck in place," Brown said.

Re-use options

Brown said options for Maureen include: host platform for satellite developments; bridge-linked to a gas processing platform; host platform for subsea wells; or split to become a storage unit and topsides for another jacket.

"The most suitable option," said Brown, "would be to continue to use the existing process and facilities without further modifications. In this mode the platform could continue to work as a drilling, production, quarters, and storage facility."

The company has no developments under way that could utilize the platform, although it is considering using it as a means of paying for a farmout of another operator's license.

Meanwhile, Phillips has begun touting the platform to oil producers worldwide.

"The main limitation on re-use is water depth," said Brown. "For the North Sea the range is 90-98 m of water. This can be increased to 125 m through the use of concrete plinths, gravel islands, or new leg sections.

"Outside the North Sea, where wave heights are not so severe, the platform could be used in even deeper water."