33/9-13 S

General

Well 33/9-13 S was drilled on the Statfjord Nord Field on the Tampen Spur area in the North Sea. The primary objective was to prove oil in the Brent Group to the northeast of the 33/9-8 discovery well. Secondary objective was to test the Statfjord Group in a position up-dip of the 33/9-8 location.

Operations and results

Well 33/9-13 S was spudded with the semi-submersible installation Ross Isle on 14 October 1987 and drilled to TD at 3077 m in the Early Jurassic Statfjord Group. The well location was moved ca 300 m to the south-southwest to avoid a potential shallow gas zone at 381 m. The well was deviated back to the original target position with maximum deviation 34.3° at 1739 m. Shallow gas was encountered at 399.5 m, 399.9m, 404.5 m, and 547 m. No significant problem was encountered in the operations. The well was drilled with seawater and hi-vis bentonite down to 398 m, with gypsum/polymer mud from 398 m to 2378 m, and with lignosulphonate/bentonite mud from 2378 m to TD.

The Brent Group, Rannoch Formation was encountered at 2726 m and was completely oil filled down-to 2795 m (2720 m TVD) with shows on claystones and siltstones down to top Dunlin Group. The Statfjord Group was encountered at 3003 m and was water filled. Shows were described only within the Brent Group.

Four cores were cut in the Brent and uppermost Dunlin Groups within the interval 2732 - 2828.3 m. No fluid samples were taken on wire line.

The well was permanently abandoned on 24 December 1987 as an oil appraisal well.

Testing

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