34/6-5 S

General

Well 34/6-5 S was drilled to test the Garantiana West prospect in the Northern part of the Tampen Spur in the North Sea. The primary objective was to prove oil and establish the oil-water contact in the Early Jurassic Cook Formation. Secondary objective was the Nansen Formation. In case of discovery a Drill Stem Test would be carried out.

Operations and results

Wildcat well 34/6-5 S was spudded with the semi-submersible installation West Hercules on 18 March 2021 and drilled to TD at 4036 m (3982.8 m TVD) m in the Early Jurassic Cook Formation. Drilling started with a data acquisition 8 1/2' pilot hole drilled down to 1350 m, lithology in this interval is based on logs from this hole. No shallow gas was seen in the pilot hole. The main well was drilled vertical to 2800 m, building to a ~19 inclination from 3203 m and keeping same until TD. After reaching TD, the BHA got stuck while pulling out of hole at 3806 m. It was decided to drill a technical side-track to perform the wireline program on the Cook Formation and the Drill Stem Test operations. The 34/6-5 S T2 well was side-tracked from the 9 5/8" liner, through a milled window at 3474 m to 3480 m. It was drilled to a total depth of 3833 m (3781 m TVD) in the Burton Formation. The 34/6-5 S well was drilled with seawater and hi-vis pills down to 1370 m, with Versatec oil-based mud from 1370 m to 3535 m, and with Exploradrill oil-based mud from 3535 m to TD. The 34/6-5 S T2 well was drilled with Exploradrill oil-based mud from kick-off to 3833 m.

Top of Cook Formation was encountered with oil at 3651 m (3619 m TVD). Pressure data and fluid sample densities indicated the oil-water contact to be at 3747.5 m (3703 m TVD). Pressure measurements indicate a similar pressure reg