7228/2-1 S

General

Well 7228/2-1 S is located on the western margin of the Nordkapp Basin close to the Nyslepp Fault Complex. It was designed to drill a large salt induced anticline that is bisected by a major north - south trending fault. Due to the large Triassic throw on the fault, the up-thrown and downthrown parts of the structure were thought to represent separate prospects. The downthrown prospect seemed to have the thickest accumulation of Triassic Anisian/Early Ladinian deposits, and was the primary objective of the well. Secondary objectives were other Middle/Upper Triassic and Jurassic sandstones. To be able to meet all obligations and at the same time test the primary objective without leaving significant potential up-dip, the well path was planned deviated at approximately 30 degrees in a northeasterly direction along seismic line MN89-603. Several reflectors in the interval 397 m to 593 m were thought to represent sand layers with possible shallow gas. The strongest amplitude anomaly was at 435 m.

Operations and results

Wildcat well 7228/2-1 S was spudded with the semi-submersible rig Ross Rig 21 August 1989 and drilled to TD at 4300 m in the Early Triassic Havert Formation. The well was deviated from 1475 m. At 2902 m the bottom hole assembly was lost in the hole, and the well had to be sidetracked from 2700 m. The well was drilled with seawater and hi-vis pills down to 1013 m, with KCl / polymer from 1013 m to 2206 m, with lignosulphonate from 2206 m to 3663 m, and with KCl / polymer from 3663 m to TD. No shallow gas was encountered in the well.

Reservoir quality sands were found in the Jurassic and uppermost Triassic Stø, Nordmela, Tubåen, Fruholmen, and Snadd formations. Of these the Nordmela and Tubåen sands had the best