34/7-26 S

General

Appraisal well 34/7-26 S is located on in the Tampen area in the Northern North Sea. It was the third well drilled on the "H-Central" prospect between the Gullfaks and the Vigdis Fields. 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 drilled deviated from slot J-3 on Tordis Extension Template, approximately 2500 m south of the discovery well 34/7-21. It was spudded on 19 August 1997 and drilled with the semi-submersible installation Scarabeo 5. At 356 m an interval with shallow gas was encountered. The well started to flow with indications of gas. The well stopped flowing when the mud was weighted up to 1.25 s.g. mud. The well was drilled deviated already from 363 m. At 1100 m the inclination was 64 deg as per planned well path. Due to the need of the rig for clean up work on well 34/7-B-2 H, the well was suspended after drilling 12 1/4" section down to 4193 m (2248 m TVD) and setting 9 5/8" casing at 4181 m in the Late Cretaceous Kyrre Formation. The well was drilled with spud mud down to 363 m, with KCl mud from 363 m to 1380 m, and with a pseudo oil based mud (Ancotec with Novamul) from 1380 m to TD.

In the Nordland Group the well penetrated clay/claystone with some beds of sand. The sandy Utsira Formation was encountered at between 1003 m to 1348 m. The Hordaland Group consisted of clay/claystone, but some major sand beds were encountered in the interval 1665 m to 1830 m. In the Shetland Group mainly claystones with limestone beds were penetrated. There were no shows reported from the drilled section.

No cores were cut and no wire line pressures or fluid samples were t