7122/7-3

General

Well 7122/7-3 was drilled on the Goliat Field, which is located approximately 55 km to the south-east of the Snøhvit Field. The Goliat structure is located on the crestal part of a major northeast-southwest trending roll-over anticline situated in the southeastern part of the Hammerfest Basin, along the Troms-Finmark Fault. The primary purpose of the well was to appraise the hydrocarbon potential of the Early Jurassic / Late Triassic (the 7122/7-1 Goliat Discovery). The secondary purpose was to test the potential throughout the Triassic and Late Permian. Permian was the drilling commitment for the licence.

Operations and results

Well 7122/7-3 was spudded with the semi-submersible installation Eirik Raude on 24 October 2005 and drilled to TD at 2726 m in limestone/claystone of the Late Permian Røye Formation. No serious problem was encountered in the operations. The well was drilled with seawater/high viscous sweeps with pre-hydrated bentonite mud down to 538 m and with K/Na Format Polymer mud from 538 m to TD.

The top of the Tubåen reservoir was found at 1087 m, 5 m deeper than prognosis. The reservoir had a gas cap with a GOC at 1145.6 m and oil below. No OWC was found. Top Snadd Formation reservoir was encountered at 1180 m, 23 m shallower than prognosis. The reservoir was oil bearing with a true OWC at 1199.5 m and was in a pressure regime different from the Tubåen reservoir pressure. The third reservoir was found in the Kobbe Formation at 1808 m, 29 m shallower than the prognosis. The reservoir was oil bearing. Oil was confirmed down to 1875.3 m by MDT fluid scanning, and the oil water contact was interpreted to be at 1878 m based on intersection between oil and water gradients.

<span