7219/8-1 S

General

Exploration well 7219/8-1 S is located in the Bjørnøya Sør area west of the Veslemøy High. This was a new geological province and hence the well was a true wildcat. The well was drilled up-dip of a rotated fault block at Late to Middle Jurassic level. The primary purpose of the well 7219/8-1 S was to test the Middle Jurassic Stø Formation. A secondary objective was to test possible sandstone in Late Jurassic Hekkingen Formation, and finally, to test possible sandstone in a defined stratigraphic trap in the Early Cretaceous sequences.

Operations and results

Well 7219/8-1 S was spudded with the semi submersible installation Ross Rig on 5 October 1992 and drilled to TD at 4611.5 m, 91 m into the Early - Middle Jurassic Stø Formation. The well was drilled deviated towards northwest with a direction of approximately 294 degrees with approximately 22 degrees inclination. Kick off point was at 1396 m. No shallow gas was identified. The well was drilled with spud mud down to 1018 m and with KCl / polymer / Anco 208 (glycol additive) mud from 1018 m to TD. It was one of the first to be drilled with a glycol mud system to inhibit reactve shales.

Down to the Base Cretaceous at 3471.5 m (3343 m TVD RKB), the well penetrated mainly claystones. The shallowest prospect, the Cretaceous sequence, was penetrated in a distal position, and hence was most likely shaled out. The Jurassic comprised the Late Jurassic Hekkingen and Fuglen Formations and the Early to Middle Jurassic Stø Formation. The secondary Hekkingen prospect was penetrated about 720 m deeper than prognosed and was only 9 m thick. Pressure test indicated a tight formation. The large difference between the prognosed and actual depth was mainly due to a much thicker Early Cretaceous sequence than prognosed. The main prospect, the Stø Formation, was penetrated 450 m deeper than prognosed. The Sandstone with porosity in order of 5-8%, was water bearing. The relatively tight sandsto