ID: 55
OBJECTID: 55
wlbNpdidWellbore: 57
wlbName: 7/11-7
wlbHistory:

General

The primary objective of the wildcat 7/11-7 S was Late Jurassic sandstone surrounding a small salt piercement below the Paleocene Cod Field reservoir. Several discoveries had been made in the vicinity of Cod, in the Upper Jurassic Ula Formation. The Triassic and Permian constituted secondary targets. The well was drilled from the Cod platform with planned bottom hole location ca 0.9 km to the east.

Operations and results

Wildcat well 7/11-7 S was spudded from the fixed installation Cod on 29 December 1982 and drilled deviated to TD at 4927 m (4661 m TVD) m in the Late Permian Zechstein Group. The well was scheduled as a 150-day project but a full drilling crew was still present on day 349 and it took until day 364 to set a plug above the last set of perforations. The length of this project was due to problems in drilling and extended testing to adequately evaluate the three zones of interest. There were delays in setting plugs, running casing, fishing, and installing necessary 10,000 psi surface equipment. The testing delays included problems with setting DHSV's, parted tubing, aborted stimulations, bad weather, and bailing operations. The well was drilled with seawater/lignite and Desco, an organic thinner.

The well reached all three targets. Late Jurassic Ula Formation sandstone was encountered at 4527 m. The Ula Formation rested unconformable on Triassic Skagerrak Formation sandstone at 4566 m. The Permian Zechstein dolomites were encountered at 4856 m. Good shows were recorded in the Ula Formation, with weaker shows extending down to 4609 m in the Triassic Skagerrak Formation. A second Triassic zone with weak shows was observed at 4785 m to 4810 m. Source rock formations were found in the Tertiary interval from 1820 m to 2500 m, and in the Late Jurassic shales of the Mandal and Farsund Formations at 4405 m to 4527. The Tertiary interval had TOC in the range 2 - 4 %, Hydrogen Index from 100 to 120 mg HC/g rock, and was
wlbHistoryDateUpdated: 2016-05-19T00:00:00