34/7-35 S

General

Well 34/7-35 S was drilled on Tampen Spur in the northern North Sea, just north of the Gullfaks field. The objectives of the well was to test the presence of oil in Intra Draupne Formation sandstone (Karpe prospect) and in Brent Group sandstones (Svarthå prospect).

Operations and results

Because of a shallow gas warning, a pilot hole 34/7-U-19 was spudded 22 m east from the main hole location and drilled to 1120 m in the Hordaland Group. No indication of shallow gas was observed on LWD or by the ROV.

Wildcat well 34/7-35 S was spudded with the semi-submersible installation Ocean Vanguard on 8 May 2012. The well was first drilled to a total depth of 4158 m. When pulling out the BHA was stuck at 4094 m. The drill string was cut at 3942 m, but attempts to fish the BHA were unsuccessful and the well was side tracked from 3506 m as 34/7-35 ST2. The sidetrack was drilled to final TD at 4393 m (3710 m TVD) in the Middle Jurassic Ness Formation. The well is vertical down to 2100 m and reach a ca 55 deg sailing angle at 3040 m. The well was drilled with seawater down to 1104 m, with Performadril mud from 1104 m to 2015 m, and with XP-07 oil based mud from 2015 m to final TD.

Some hydrocarbons shows were observed in sandstone from 1371 to 1385 m the Hordaland Group and in thin sandstones between 1920 and 1950 m in the Sele/Lista Formations. Both shows zones were associated to clear resistivity peaks over the sandstones. Top Draupne was encountered at 3152 m (2991.8 m TVD) and top Brent Group, Tarbert Formation, at 4276 m (3635.4 m TVD). Several thin sand bodies were drilled within the Draupne Formation and some thick sandstones were found in the Heather Formation, but with no indicat