ID: 366
OBJECTID: 366
wlbNpdidWellbore: 371
wlbName: 25/11-11
wlbHistory:

General

Well 25/11-11 was drilled to appraise the Balder Field on the Utsira High in the North Sea. The objective was to establish the presence of an accumulation of oil sand in the western part of the Balder Field, and evaluate the geologic concept of sand-shale distribution and reservoir quality. The top of the reservoir was anticipated to be at 1708 m MSL.

Operations and results

Appraisal well 25/11-11 was spudded with the semi-submersible installation Glomar Biscay II on 18 February 1981 and drilled to TD at 1960 m in the Danian age chalk of the Ekofisk Formation. The well was drilled with seawater and gel/lignosulphonate.

One main oil sand of Paleocene age (Heimdal Formation) was encountered at 1754 m (1729 m TVD MSL). It was 141.5 m thick and was oil-bearing in the upper 29 m down to an OWC at 1783 m (1758 m TVD MSL). This OWC was in agreement with the general field OWC in the area. Average porosity in the oil sand was 32.6%. Shows of hydrocarbons were also present in a 16 m thick Intra Balder Formation Sandstone with top at 1698 m, and in thin sand stringers within the Sele Formation.

No cores were cut and no wire line fluid samples were taken.

The well was permanently abandoned on 18 March as an oil appraisal.

Testing

No drill stem test was performed.

wlbHistoryDateUpdated: 2016-07-06T00:00:00