Foinaven start tops NW Europe action

BP Exploration Operating Co. Ltd. has begun oil production in U.K.'s West of Shetland offshore area, after a much-delayed development.

Block 204/24a Foinaven field was brought on stream on Nov. 26, roughly 2 years after first oil was originally anticipated, at a rate of 15,000 b/d of oil. At OGJ presstime, four wells were on stream, producing a total of 40,000 b/d.

In other action, Shell U.K. Exploration & Production began production from North Sea Block 28/7 Curlew field, following a trouble-free fast track development.

Meanwhile, U.K.'s Department of Trade and Industry approved development plans for three southern North Sea gas fields: Block 48/12d Malory operated by Mobil North Sea Ltd., and Block 49/28 Bure West and Deben, operated by ARCO British Ltd.

Foinaven

Foinaven was developed with subsea wellheads connected through two seabed manifolds to a floating production, storage, and offloading (FPSO) vessel.

Petrojarl Foinaven FPSO is moored in 500 m of water and is emptied every 3-4 days by one of two dedicated shuttle tankers, Petrotroll and Petrotrym.

Early development will center on Foinaven's central reservoir, which has estimated reserves of 200 million bbl of oil. Related accumulations are thought to boost reserves to 250-500 million bbl.

The production vessel has capacity to process 120,000 b/d of oil. A BP official said 95,000 b/d is expected to be Foinaven's typical output at plateau.

The official said Foinaven delays resulted from two unrelated problems, both of which required recovery of a subsea manifold from the seabed.

In May 1996, BP discovered a corrosion problem with the first manifold installed, noting, "The cathodic protection was too active." The operator recovered the manifold for repair and put the second manifold in its place.

Then in spring 1997, BP discovered a problem with seals in the second manifold's valve stems and in five christmas trees, all of which had to be recovered for repair (OGJ, May 19, 1997, p. 33).

"The problem was minor in itself," said the official, "but the only way to solve it was to pull the manifold and trees back from the seabed."

Now BP is applying lessons learned in Foinaven to nearby Schiehallion, currently under development with a production ship and subsea manifolds.

"The lesson we've learned is in putting the bits of the jigsaw together rather than in designing the jigsaw," said the official.

The faulty equipment for the second manifold and christmas trees was supplied by Cooper Cameron Corp., Aberdeen. The official said BP is pursuing compensation but that an agreement has not yet been reached.

Foinaven development was also hindered by the environmental group Greenpeace, which targeted BP in a campaign to prevent oil field development in the previously virgin West of Shetland area (OGJ, Aug. 25, 1997, p. 40).

Curlew

Shell's Curlew field began production on Nov. 22, following an 18-month development program that cost £300 million.

Curlew also was developed with a leased FPSO producing oil from wells connected back via manifolds in two drilling centers.

The Maersk Curlew ship has capacity to store 560,000 bbl of oil and is expected to produce 45,000 b/d of oil and 100 MMcfd of gas at peak (OGJ, Aug. 12, 1996, p. 27).

Curlew has estimated reserves of 71 million bbl of oil and condensate and 244 bcf of gas. Oil is exported by shuttle tanker, while gas is piped via Shell's nearby Fulmar pipeline to St. Fergus terminal near Aberdeen.

New developments

Mobil's Malory find will be developed with a minimum-facilities platform sending gas ashore to Bacton terminal via the Lancelot area pipeline system.

First gas is slated for October 1998 at an initial flow rate of 45 MMcfd. Field life is expected to be 9 years. The platform will be built by Odebrecht-SLP Engineering Ltd., Lowestoft, U.K.

ARCO's Bure West and Deben will be developed with single wells completed subsea and tied back to Thames AR platform, a minimum-facilities structure to be bridge-linked to the existing Thames complex.

West Bure is an extension of Bure field, currently producing, with estimated reserves of 31 bcf of gas. It lies 11 km northwest of Thames. Deben lies 6 km northwest of Thames and has estimated reserves of 33 bcf of gas.

Bure West and Deben are also due on stream in October 1998, and their platform is also to be built by SLP. The platform will be built to the Sea Harvester design.