35/9-10 A

General

Well 35/9-10 A is a geologic sidetrack to 35/9-10 S. Sidetrack 35/9-10 was drilled to appraise the southwest flank of the 35/9-7 Skarfjell discovery. The Skarfjell discovery is situated on the Uer Terrace between the Fram and the Gjøa Fields in the North Sea. The primary objective was to prove additional reserves in the Late Jurassic Intra Heather Sandstones. Two such sandstones were expected.

Operations and results

Wildcat well 35/9-10 A was drilled with the semi-submersible installation Transocean Arctic. It was kicked off from 930 m in the primary well bore on 26 November 2013 and drilled to 976 m where it was observed that the BHA did not follow the planned well path. A new kick-off plug was placed and a second kick-off from 878.5 m was made. This well path is termed 35/9-10 AT2. It was drilled successfully to TD at 3203 m (2862 m TVD) m in the Middle Jurassic Rannoch Formation. The well was drilled deviated down to ca 2700 m and vertical from there to TD. The deviated section had a sail angle of ca 47 °. No significant problem was encountered in the operations. The well was drilled with seawater XP-07 oil based mud from kick-off to TD.

Sidetrack 35/9-10 A, drilled near the top of the structure in the southwest, found a 59-meter gross gas column in the Intra Heather Sandstone 2 (IHS 2). The IHS 2 was penetrated from 2734.5 to 2793 m (2393 to 2451.5 m TVD). It had better reservoir properties than expected with a 66% N/G and an average porosity of 25%. Pressure data indicate that the gas cap is in communication with the oil proven in the 35/9-7 & -8 wells in the northern part of Skarfjell. The Intra Heather Sandstone 1 (IHS 1) was penetrated from 2932.5 to 2936.5 m (2590.9 to 2594.1 m TVD). It contained oil and h