7225/3-1

General

Well 7225/3-1 was the first well to be drilled on the faulted Norvarg Dome on the Bjarmeland Platform in the Barents Sea. It was drilled fairly close to the crest of the structure. The primary objective was to prove hydrocarbon presence, determine fluid nature and evaluate reservoir characteristics in sandstones of the Late Triassic (Carnian) Lower Snadd Formation and the Early Triassic Kobbe Formation. Secondary objective was to prove hydrocarbons in the Jurassic Stø Formation, the Early Triassic Havert Formation, and the Permian Tempelfjorden and Bjarmeland groups.

Operations and results

Wildcat well 7225/3-1 was spudded with the semi-submersible installation West Phoenix on 30 April 2011 and drilled to TD at 4150 m in the Permian Isbjørn Formation. No major drilling problems were encountered, but P&A in the upper part was subject to extensive delays associated with trying to retrieve casing, failed cement plugs or leak in 20" casing and extra time spent trying to locate the source of a gas leak. The well was drilled with bentonite mud with hiv-vis pills down to 672 m, and with KCl/polymer mud from 672 m to TD.

Gas was proven both in intervals from the Jurassic and the Triassic. The Jurassic Stø Formation was gas bearing from top at 726 m to a likely GWC at 766.5 m. In the Triassic the upper part of the Snadd Formation with top at 804 m was supposed to be gas bearing, but this was not proven by sampling. The best Snadd sands, below 1040 m, could be sampled and they were water bearing. An Intra-Carnian section was penetrated from 1146 m to 1521 m. It contained gas in two zones with GWC's at 1218 m and ca 1250 m, respectively, and in a third thin sandstone from 1347 m to 1357 m. The upper and the lowermost Intra-Ca