7119/7-1

General

Exploration well 7119/7-1 is located in the Tromsø Basin, ca 30 km west of the Snøhvit Field area. The primary well objective was to test a sandstone and/or limestone reservoir of Late Cretaceous age. The secondary objective of the well was to test a westward thinning wedge interpreted as a sandstone reservoir of Late Cretaceous age. A further objective of the well was to penetrate the Cenomanian unconformity with possible associated basal sandstones. Planned TD was 4100 m or 100 m below the Cenomanian unconformity.

Operations and results

Well 7119/7-1 was spudded with the semi-submersible installation Treasure Seeker on 12 July 1983 and was drilled to a total depth of 3167 m in salt. No major problems occurred during drilling. The well was drilled with seawater and bentonite down to 622 m, and with KCl/polymer mud from 622 m to 2518 m. From 2518 m to TD the mud was converted to a dispersed gel system allowing natural depletion of the KCL.

No rocks with reservoir qualities were penetrated by this well. The prognosed Campanian sandstones/limestones were developed as claystones, sometimes silty with occasional limestone stringers. Insignificant traces of sand were noted in that interval. Top Campanian was found between 1375 m and 1377 m based on biostratigraphy. The base Late Cretaceous wedge interpreted as sandstone was found poorly developed as siltstones and silty claystones without reservoir characteristics. The base Late Cretaceous was encountered between 2796.5 m and 2810.5 m based on biostratigraphy. The Cenomanian unconformity was penetrated at 2529 m without any associated sandstones. The well encountered evaporites of possible Permian age at 3094.5 m. No shows were recorded in the well. No conventional cores were cut and no fluid samples taken

The well was permanently abandoned on 11 September 1983 as a dry hole.

Testing

No drill stem test was performed