8/5-1

General

Well 8/5-1 was drilled on the Ogna prospect on the Sørvestlandet High in the North Sea. The primary objective was to test the hydrocarbon potential in sandstones of the Middle Jurassic Sandnes and/or Bryne formations. A secondary objective was to evaluate the reservoir quality of the deeper Triassic sediments.

Operations and results

Wildcat well 8/5-1 was spudded with the jack-up installation Mærsk Guardian on 10 January 2013 and drilled to TD at 2405 m in the Triassic Smith Bank Formation. Shallow gas was encountered at several levels in the Nordland and Hordaland Group, also during the P&A phase, otherwise operations proceeded without significant problems. The well was drilled with seawater and bentonite hi-vis sweeps down to 228 m, with KCl/Polymer/GEM mud from 228 m to 905 m, and with Performadril/Glycol mud from 905 m to TD.

A ca 50 m thick and very rich but immature Late Jurassic Tau Formation source rock was penetrated by the well. Below Tau the well penetrated a 26 m thick Egersund Formation before the Sandnes Formation was encountered at 2339 m. The Sandnes Formation proved to be a 32 m thick siltstone. The well also drilled 34 m into Triassic aged Smith Bank Formation. The reservoir quality was poor in both target formations. The well was found to be dry without oil shows throughout. The structure was dependent on charge from a mature source rock in a local inlier basin southwest of the structure. The lack of hydrocarbons other than shallow gas is believed to be due to lack of such charge.

No cores were cut. No formation evaluation wire line logs were run in the well and no wire line fluid samples were taken

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