7228/9-1 S

General

Wildcat well 7228/9-1 S is located on the western margin of the Finnmark Platform in the Nordkapp Basin South. The objective of the well was to test the Jurassic and Triassic prospects above the salt with the Early Triassic Klappmyss Formation as the primary target. Further objectives of this wildcat well was to obtain stratigraphic information from the Palaeozoic for future exploration in the area and to gather as much geological information as possible regarding reservoir, source and cap rock intervals. The well position was chosen to leave a minimum of untested potential up-dip from the well location and to avoid faults that could disturb a good seismic tie. Total depth was planned to 300 m below the base Sakmarian reflector, but not deeper than 4960 m. If massive evaporites were encountered below the Base Sakmarian reflector, drilling would terminate within 50 m. The well would be deviated from approximately 2300 m in direction 270 deg to avoid major faults and to test potential reserves up-dip. No shallow gas was expected in the well.

The well is Type Well for the Ulv Formation and Reference Well for the Røye and Ørret formations.

Operations and results

Wildcat well 7228/9-1 S was spudded with the semi-submersible rig Ross Rig 22 December 1989. Due to severe difficulties with tight hole in the top-hole section, the well was re-spudded twice. The primary reason for the problems was the extremely reactive swelling clay. Exposed to water, the clay swelled without space to expand and thereby raise the formation pressure. The well was drilled to TD at 4576 m in Early Permian evaporites. No shallow gas was observed in the well. The well was drilled with seawater and CMC hi-vis pills down to 958 m, and with KCl/polymer mud f