16/5-2 S

General

Well 16/5-2 S was drilled to appraise the southern flank of the Avaldsnes (subsequently Johan Sverdrup) discovery on the Utsira High in the North Sea. The objectives were to prove the presence and quality of Late and Middle Jurassic

sequences on the south flank of the Johan Sverdrup structure; to prove an oil column of 20 to 45 m; and to calibrate the seismic interpretation and the depth conversion. The well was planned to reach total depth in sediments of Triassic age at a depth of approximately 2180 m TVD RKB.

Operations and results

Appraisal well 16/5-2 S was spudded with the semi-submersible installation Bredford Dolphin on 28 November 2011 and drilled to TD at 2042 m (2037 m TVD) in the Late Triassic Skagerrak Formation. The well was drilled with Sea water and hi-vis pills down to 755 m and with Performadril Water Based Mud from 755 m to TD.

At 1958 m the well encountered a 9 m thick sequence of Late Jurassic Draupne Formation sandstone of excellent quality. No Middle Jurassic sediments were found. The seismic interpretation of Base Jurassic was encountered shallower than expected while the BCU was deeper than expected. This meant that the Late Jurassic Intra-Draupne Formation sandstone was penetrated below the regional free water level seen in neighbouring wells in the Johan Sverdrup Discovery. A water gradient of 1.022 g/cc was confirmed in the reservoir interval. Residual hydrocarbon shows were observed in some intervals in the conventional cores from 1959 m to 1967 m, otherwise no shows were reported from the well.

Five cores were cut from 1919 m to 1974 m with good recovery. A fluid sample was acquired using the M