30/2-5 S

General

Well 30/2-5 S was drilled to test the Atlantis prospect on the Mokkukalven Fault Complex about 17 kilometres south of the Kvitebjørn field in the North Sea. The primary objective was to prove petroleum in reservoir rocks in the Middle Jurassic Brent Group.

Operations and results

An 8 1/2" pilot hole 30/2-U-1 was drilled down to 1128 m between 7 and 9 March 2020 to investigate shallow gas and to reduce complexity and uncertainty related to drilling of the main Atlantis wellbore. No shallow gas was observed in the pilot hole.

Wildcat well 30/2-5 S was spudded with the semi-submersible installation West Hercules on 14 May 2020 and drilled to TD at 4390 m (4388.4 m TVD) in the Early Jurassic Drake Formation. Drilling of this HPHT well proceeded without significant problems. The well was drilled with seawater and hi-vis pills down to 1175 m, with RheGuard oil-based mud from 1175 to 4120 m, and with Warp oil-based mud from 4120 m to TD.

Well 30/2-5 S encountered top Brent Group at 4203 m (4203 m TVD) with a gas-condensate column of about 160 metres in the Brent Group (the Tarbert, Ness, Etive and Rannoch Formations), of which 60 metres comprise effective sandstone reservoir. The Ness Formation has 30 metres of sandstone with poor to moderate reservoir quality, while the Etive Formation has 15 metres of sandstone, primarily of moderate quality. The Tarbert Formation has 10 metres of sandstone with poor to moderate reservoir quality, while the Rannoch Formation has 5 metres of poor-quality sandstone. Pressure points indicate a similar pressure regime in all reservoir sandstones. No oil shows were observed as expected from very low-molecular weight hydrocarbons in a gas-condensate<