2/11-7

General

Well 2/11-7 was designed to test a Jurassic reservoir half way between the crest and the mapped closing contour of a fault controlled structure up dip from the Danish well Gert-1 in the same structure. The primary objective was the middle Jurassic sands, expected to come in at 4696 m. Seismic anomalies at 320, 350, and 445 m respectively. Prognosed TD was 5025 m.

Operations and results

Wildcat well 2/11-7 was spudded with Wi1h. Wi1helmsen semi-submersible installation Treasure Scout on 16 April 1986 and drilled to TD at 5042 m in Late Jurassic shales of the Haugesund Formation. The well was flow checked at 318 m and 445 m, without any indications of gas. The well was drilled with seawater and hi-vis pills down to 1016 m, with KCl mud from 1016 m to 3737 m, and with Lignosulfonate mud from 3737 m to TD. Due to high gas readings and subsequent problems with increased mud weight and lost circulation up to 14% oil was added to the mud at 3799 m. This mud was subsequently circulated out and displaced with new mud, but a level of 1% to 8% oil was recorded in the mud from 3799 m to TD. Due to high formation pressure and safety problems, drilling was terminated in Late Jurassic shales before having reached the target Middle Jurassic sand.

Shows were reported from lowermost Chalk Group, limestones of the Cromer Knoll Group, and from Upper Jurassic Dolomite and sandstone stringers. No conventional cores were cut. Thirty sidewall cores were attempted from 3801,5 m to 3756 m whereof 10 were recovered. No fluid samples were taken. The well was permanently abandoned as a dry well with shows on 6 September 1986.

Testing

No drill stem test was performed