30/8-5

General

Well 30/8-5 was drilled on the Tune Field on the Mokkukalven Fault Complex west of the Oseberg fault block in the North Sea. The primary objective was to collect data for the development of the Tune field, Statfjord reservoir.

Operations and results

A 9 7/8” shallow gas pilot hole was drilled at the well location to a total depth of 500 m. No indications of shallow gas were observed.

Appraisal well 30/8-5 was spudded with the semi-submersible installation Deepsea Atlantic on 2 December 2017.

It was drilled to 3637 m in a sand in the Shetland Group where a fluid influx was recorded. The blow-out preventer (BOP) was closed and the well was shut in. High pressure was measured at surface. The ensuing well control situation was successfully resolved. Based on formation stress and strength at the 14” shoe the well was plugged and cemented back to the shoe. A technical side-track 30/8-5 T2 was kicked off from 30/8-5 at 3007 m. The side-track was drilled approximately 20 m north of 30/8-5. The logs from the two wellbores correlate very well but show some differences towards TD. After a drill break at 3563 m, 7 m fluid influx was again recorded, 72 m TVD above the sand with high pressure and kick in 30/8-5. It was decided to terminate the well at 3563 m. The well was drilled with seawater and hi-vis pills down to 1153 m, with Innovert NS oil-based mud down to 3156 m and with Bara ECD oil-based mud from 3156 m to final TD.

The well objectives were not achieved. No oil shows were observed cuttings in either wellbore. During the shut-in after the kick, the MWD memory data showed that the temperature stabilized at a 136 °C.