34/7-26 SR

General

Appraisal well 34/7-26 SR is located in the Tampen area in the Northern North Sea. It is a re-entry of well 34/7-26 S, which was suspended when the rig was needed for clean up work on well 34/7-B-2 H. The well had two primary objectives. Firstly, to perform an optimum data collection programme in the Top Draupne sandstone and in lower Shetland Group sands if these were present. Secondly, if there was thick and good quality Top Draupne sands present, the well was to be long-termed tested for six months to the Gullfaks-C Platform.

Operations and results

Well 34/7-26 S was re-entered (34/7-26 SR) on 2 February 1998 through slot J-3 on Tordis Extension Template, approximately 2500 m south of the discovery well 34/7-21. The well was drilled with the semi-submersible installation Scarabeo 5. New Formation was drilled from below the 9 5/8" casing shoe at 4193 m in the primary well bore to final TD at 4690 m (2657.6 m TVD) in Middle Jurassic sediments of the Heather Formation. Inclination dropped from 59 to 20 deg in about 300 m. There were no particular problems with drilling, but the wire line logging programme was cancelled. Probably due to a severe rat hole below the 9 5/8" casing shoe, it was not possible to get any wire line logging tools into the open hole section. The well bore was drilled all through to TD with a pseudo oil based mud (Ancotec with Novamul).

The Top Cromer Knoll Group was penetrated at 4505 m (2480 m TVD), and consisted of the Rødby Formation from 4505 m to 4512 m and the Mime Formation from 4512 to 4528 m (2486 to 2502 m TVD). Two thin sandstones (approx. 1 and 2 m TVD) were encountered within the Mime Formation. The upper sandstone was grey in colour and bioturbated. The sandstone was dated to the Turonian-Coniacian stage. The lower sandstone exhibited a brown colour, and was bioturbated in the lower part. The lower sandstone was dated to the Middle Albian - early Late Albian stage. Both of the