25/8-6

General

Well 25/8-6 was drilled to appraise the 25/8-5 S Discovery (Jotun) resource base and to confirm the OWC. The well is located close to the crest of the field, close to the western block boundary and PL103, who participated in the well.

The well was drilled as a possible future vertical sub-sea producer.

Operations and results

Appraisal well 25/8-6 was spudded with the semi-submersible installation "Vildkat Explorer" on 19 May 1995 and drilled to TD at 2565 m. The well was drilled with seawater and hi-vis pills down to 1060 m and KCl/glycol mud from 1060 m to TD. Due to bad hole condition it was impossible to get wire line logs below 1460 m. The well was plugged back on 6 June and technically sidetracked& (25/8-6T2) from just below the 13 3/8" casing at 1073 m using "Lo-Tox" mineral oil based mud. This well bore built up to 13& at 1329 m and then dropped back to vertical at 1600 m, the well was kept vertical down through the reservoir. It was drilled to TD at 2577 m in the in the Early Paleocene Ekofisk Formation. Successful wire line logging was achieved in this well bore. The well confirmed oil in the Heimdal Formation with OWC at 2090 m TVD SS (2122.6 m RKB in the technical sidetrack) in clean sand.

Eight cores were cut in the first well bore. Two were cut in shales of the Lista Formation (2054m to 2057 m and 2057 m to 2065 m). Due to very slow coring rate, coring was discontinued and a 12 1/4" hole was drilled down to 2077 m at the next core point. Six cores were subsequently cut in Heimdal Formation sandstone in the interval 2077 m to 2137.5 m. MDT fluid samples were taken in the Heimdal Formation at 2082.2 m (oil), 2122.1 m (oil), 2123.0 m (water + ca 15% oil), 2143.5 m (water), and 2145 m (water). After running TD logs, a string of 10-3/4" x 9-5/8" production casing was run and cemented, and the well was suspended on 27 June 1995 as an oil appraisal and potential future