2/7-13

General

Exploration well 2/7-13 was drilled to the East of an intrusive salt dome in the Ekofisk area of the Norwegian sector of the North Sea. The structure had already been investigated by wells 1/9-4 and 1/9-5 to the west, and also above the salt dome in 2/7-12. The Danian/Late Cretaceous was the primary objective. A secondary objective was the possibility of a reservoir on the flank of the dome with the salt forming a seal.

Operations and results

Well 2/7-13 was spudded with the jack-up installation Dyvi Beta on 1 February 1979 and drilled to TD at 3388 m in the Early Cretaceous Sola Formation. No significant problems were reported from the operations. The well was drilled with spud mud/Drispac/seawater down to 1309 m, and with seawater/Drispac from 1309 m to TD.

Higher hydrocarbon gasses were observed from 975 m to 1113 m. Very poor fluorescence was noted in the clay and occasional limestone in the same interval. Poor shows occurred in limestones at 2210 - 2225 m and 2265 - 2274 m, and also in dolomite limestone stringers from 2387 - 2591 m. The Danian and Cretaceous limestones also gave poor oil shows with some staining in the Ekofisk Formation from 2719 to 2801 m. Five conventional cores with a total of 22 m recovered were taken in this zone from 2725.5 m to 2790 m. No wire line fluid samples were taken.

The well was permanently abandoned on 21 April 1979 as a dry well with shows.

Testing

Four intervals in the 8 1/2" section were tested through 7" liner. DST 1 tested the Hidra Formation from 3188 to 3257 m and produced 504 Sm3 water with 1.5% oil/day, DST 2 tested the Hod Formation from 3042 to 3085 m and produced 1441 Sm3 water with ca 3000 Sm3 gas/day, DST 3 tested the Ekofisk Formation from 2740 to 2774 m and 2793.5 to 2807 m, and DST 4 tested the Ekofisk Formation from 2697.5 to 2729 m. DST 3 and DST 4 produced only small amounts of water (1 Sm3/day and 69 Sm3/day, respect