6507/7-15 S

General

Well 6507/7-15 S was drilled on the Zidane West prospect between the Heidrun Field and the 6506/6-1 Bella Donna discovery in the Haltenbanken area of the Norwegian Sea. The primary target was the Middle Jurassic Fangst Group; Garn and Ile Formations. Secondary target levels were the Lower Cretaceous Lange Formation sandstone and the

Lower Jurassic Tilje Formation.

Operations and results

Wildcat well 6507/7-15 S was spudded with the semi-submersible installation West Alpha on 9 January 2012 and drilled to TD at 4567 m (4552 m TVD) in the Early Jurassic Tilje Formation. A 9 7/8" shallow gas pilot hole was drilled from 496 m to 649 m and shallow gas was observed at 640 - 644 m. The 26" hole was drilled to 596 m and the 20" casing was set at 594 m, above the shallow gas zone. Operations were stopped at 4124 m after setting of 9 5/8" casing due to leakage in the kill line and failure on a fail-safe valve. The well was plugged and the BOP was pulled, repaired and run again. Otherwise, operations went forth without significant problems. The well was drilled with seawater, bentonite and hi-vis sweeps down to 596 m, with KCl/freshwater dilution mud from 596 m to 1336 m, with Glydril mud from 1336 m to 2210 m, and with Versatherm oil based mud from 2210 m to TD

The well encountered gas in the Lange, Garn, Ile and Tilje Formations. The Lange Formation had gas in a sandy interval from 3586.5 m (3585.5 m TVD) down to 3634 m (3632.5 m TVD) and water up to 3679.5 m (3677.5 m TVD) based on logs. Pressure testing was difficult due to poor reservoir conditions, so no conclusive gas gradient could be established. The Fangst Group contained gas from top Garn at 4266.5 m (4255