ID: 982
OBJECTID: 982
wlbNpdidWellbore: 3042
wlbName: 35/11-10
wlbHistory:

General

Well 35/11-10 is located on the western edge of the Uer Terrace, ca 9 km North of the Troll Field. It was drilled to appraise the oil and gas discovery made in the exploration well 35/11-4, which encountered hydrocarbons in the Upper Sognefjord Formation separated from an oil column in the Lower Sognefjord Formation, in the Fensfjord Formation, and in the Brent Group. In addition the Utsira Formation was to be cored in order to obtain information about the productivity for injection water.

Operations and results

Appraisal well 35/11-10 was spudded with the semi-submersible installation West Vanguard on 19 May 1997 and drilled to TD at 2950 m in the Early Jurassic Cook Formation. Some problems were encountered with coring in the Utsira Formation. In addition the Utsira Formation was not logged due to a tight spot at 439 m. Otherwise no significant problems were encountered during operations. The well was drilled with spud mud down to 1152 m and with ANCO 2000 glycol mud from 1152 m to TD.

From MWD logs and drilling parameters the Utsira Formation proved not to be developed as a sand reservoir in this location. The well confirmed hydrocarbons in all target levels except for the Etive Formation of the Brent Group. The top Sognefjord reservoir was encountered at 1971 m. The upper part of the Sognefjord Formation was thicker and had better reservoir properties than prognosed. A gas oil contact was identified at 1987 m and an oil water contact at 2011 m. Within the range of uncertainty this was the same OWC as in the well 35/11-4 and there was pressure communication in both the water and the oil zones. The GOC however, differs between the two wells. A total of 14 m of gas pay and 22.6 m oil pay with an average porosity of 27% were encountered. The Lower Sognefjord contained oil and gas with a thin gas cap at 2037 m identified by an MDT sample. The OWC was at 2054 m, which is the same depth as in well 35/11-4. Top Fensfjord Forma
wlbHistoryDateUpdated: 2016-07-06T00:00:00