6506/11-8

Block 6506/11 is situated on the north-western part of the Halten Terrace offshore Mid-Norway. The well 6506/11-8 was drilled to appraise the 6506/11-7 Morvin Discovery, approximately 10 km north of the Kristin field. The primary objective of the well was to prove extra recoverable oil in structure, explore potential better reservoir properties and reduce depth uncertainties. The primary target was Bathonian age sandstones in the Garn and Ile Formations. Potential targets in the Tofte and Tilje Formations were also investigated by this drilling.

Operations and results

Appraisal well 6506/11-8 was spudded with the semi-submersible installation West Alpha on 24 March 2006 and drilled to TD at 4990 m in the early Jurassic Tilje Formation (extended from 4893 m, which was the planned TD of the well). No significant technical problems were encountered in the operations. The well was drilled with seawater and bentonite down to 2150 m, with Glydril water based mud (with glycols) from 2150 m to 4500 m, and with Paratherm oil based mud from 4500 m to TD. No shallow gas was observed by the ROV at the wellhead or by the MWD while drilling the 26" hole.

The well penetrated rocks of Quaternary, Tertiary, Cretaceous, and Jurassic age. Small gas peaks of up to 3.67% were observed in the lower Lange Sandstone Unit, similar to those observed in the 6506/11-7 well, indicating slight hydrocarbon charging. In the lower Lange Sandstones from 4449 m to 4479 m, very weak shows where observed. The well penetrated the Garn reservoir section at 4622.9 m and the Ile reservoir section at 4734.8 m, both formations shallower than prognosed. A HC discovery was proven both in the Garn and Ile Formations, but the MDT results suggested the formations to be tight. A MDT mini-DST was run in Tofte Formation and confirmed