25/8-20 S

General

Well 25/8-20 S Prince with side-track 25/8-20 B King is a dual branch exploration well that tested several independent targets. The well is situated north of the Balder Field on the Utsira High in the North Sea. The primary well 25/8-20 S Prince targeted Jurassic and Triassic sandstones as primary objectives and the Paleogene Hermod sandstone as secondary objective.

Operations and results

Prior to the main hole an 8 1/2" pilot hole 25/8-20-U-26 was spudded on 11 April 2021 to check for shallow hazards. The Pilot was drilled to 1107 m without encountering shallow gas or other hazards.

Wildcat well 25/8-20 S was spudded with the semi-submersible installation Scarabeo 8 on 15 April 2021 and drilled to TD at 2733 m (2408 m TVD) m in the Late Triassic Skagerrak Formation. The well was drilled vertical down to ca 1020 m and deviated from there to TD with a deviation mostly between 25 and 45 . Operations proceeded without significant problems. The well was drilled with seawater and hi-vis pills down to 243 m, with a KCl Polymer mud from 243 m to 1103 m, and with Rheguard Prime oil-based mud from 1103 m to TD.

The Early Jurassic Statfjord Group was penetrated at 2313 m (2053.5 m TVD), directly underlying the Early Cretaceous Cromer Knoll Group. The Statfjord was water wet, but with good reservoir sands in the lower part. Oil was discovered in the Skagerrak Formation. Gross thickness was 105 m with NTG of 0.34 and averaged porosity PHIT of 19%. Oil bearing sands constitute net thickness of 6.4 m. The oil-water contact was indicated by logs and pressure points to be between 2642 m and 2659 m (2325 m and 2341 m TVD). Secondary target Hermod was water bearing having gross thicknes