25/7-7

General

Well 25/7-7 was drilled to test the Busta prospect on the eastern margin of the Vana Sub-basin, west of the Utsira High in the North Sea. The primary objective was to prove hydrocarbon presence and evaluate reservoir quality in the Late

Jurassic Intra Draupne Formation sandstone (Brae Equivalent). The secondary objective was to evaluate a potential reservoir presence in the underlying Heather Formation.

Operations and results

Wildcat well 25/7-7 was spudded with the semi-submersible installation Leiv Eiriksson on 29 August 2019 and drilled to TD at 4730 m in the Middle Jurassic Heather Formation. A 9-7/8" pilot hole was drilled from below 36"x30"conductor shoe at 216.5 m to 1197 m. No shallow gas or water flow was observed. Operations proceeded without significant problems. The well was drilled with seawater and hi-vis pills down to 206 m, with KCl/Polymer mud from 206 to 1188 m, with Innovert oil-based mud from 1188 to 2784 m, and with BaraECD 2.2 oil-based mud from 2784 m to TD.

The well encountered hydrocarbons in two highly overpressured Intra-Draupne Formation sandstone intervals. The upper sand was 8 m thick with top at 4463 m and the lower was 20 m thick with top at 4490 m. The sandstone intervals are separated by a 28-meter shale interval. The overpressure in the lower sandstone is 40 bar higher than in the upper sandstone. The upper sandstone interval contains a rich gas condensate, while the lower sand encountered a light volatile oil. The sandstones are not in pressure communication with each other or with the Intra-Draupne sands in the 25/7-2 well, drilled 4.7 km to the SSW. The reservoir properties of the sandstones are good, with pay zone average po