25/10-12 S

General

Well 25/10-12 S was drilled to test the Kopervik Prospect on the west flank of the Utsira High, close to the Hanz Field in the North Sea. The primary objective was to test the hydrocarbon potential of Late Jurassic Intra-Draupne Formation sandstone. Secondary objective was sandstones in the Early-Middle Jurassic sequence (Statfjord-Sleipner-Hugin units)

Operations and results

Wildcat well 25/10-12 S was spudded with the semi-submersible installation Island Innovator on 27 October 2014. The well was drilled to a total depth of 1800 m in Early Eocene sediments in the Hordaland Group. While running the 9 5/8" casing, the string became differentially stuck at 1520 m. The well was plugged back to the 20" casing shoe and technically sidetracked as 25/10-12 ST2. The latter was drilled to final TD at 2597 m (2570 m TVD) in the Smith Bank Formation. Only MWD logs are available from the well. Wireline logging was attempted at TD of the 8 1/2" hole, however, due to problems below the 9 5/8" casing shoe, no logging was possible. The well was drilled with seawater and high viscosity pills down to 558 and with Aquadril mud from 558 m to TD.

Top Draupne Formation was penetrated at 2114 m (2087.3 m TVD). The Draupne Formation in the well consists of mudstones and interbedded thin beds of spiculitic sandstones. At 2124 m (2097.3 m TVD), the base of Draupne, there is a 1.7 m thick Intra-Draupne Formation sandstone. The well also penetrated 21 m and 19.5 m of high quality sand belonging to the Hugin and Sleipner Formations respectively, and approximately 198 m of Statfjord Group sediments with several wel