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Sticking with LWI

December 23, 2004, 13:00 CET

A commitment to light well intervention (LWI) will be maintained through 2005 by Statoil, which is exercising an option to use the Seawell monohull for such work on 144 days next year.

Deploying a ship rather than a rig for downhole operations in subsea wells cuts the cost of these jobs by roughly 50 per cent.

Seawell, which is owned by WellOps, has carried out four assignments for Statoil on the Åsgard field in the Norwegian Sea over the past year.

“This vessel will continue the 2004 programme with subsea wells on Statfjord and Gullfaks to the end of January,” reports Øyvin Jensen, head of drilling and subsea operations for the Tampen area of the North Sea.

Plans call for the 2005 campaign to start around 1 May in the Tampen area and the Halten/Nordland sector of the Norwegian Sea.

LWIs are scheduled on Åsgard for 60 days, Heidrun for 14, Statfjord East for 20, Tordis/Vigdis for 20 and Gullfaks for 30.

“We’re also considering additional work on Vigdis, Snorre and Norne, which could total an additional 55 days,” says Mr Jensen.

The procedure involves wireline-based workovers in subsea-completed wells, with the wireline run directly into the pressurised well without being contained in a riser.

That contrasts with corresponding operations on a drilling rig, where a riser needs to be installed. A monohull is also much faster to redeploy than a moored rig.

Statoil regards LWI as an important tool in its efforts to improve recovery in subsea wells from today’s level of 43 per cent to its goal of 55 per cent.