ID: 367
OBJECTID: 367
wlbNpdidWellbore: 372
wlbName: 25/11-12
wlbHistory:

General

Well 25/11-12 was drilled to appraise the Balder Field on the Utsira High in the North Sea. The objective was to establish the presence of a thick accumulation of oil sand in the north-eastern part of the Balder Field, and evaluate the geologic concept of sand-shale distribution and the reservoir quality of the Paleocene sands. The top of the reservoir was anticipated to be at 1717 m TVD MSL.

Operations and results

Appraisal well 25/11-12 was spudded with the semi-submersible installation Glomar Biscay II on 18 April 1981 on and drilled to TD at 1918 m in the Danian age chalk of the Ekofisk Formation. The well was drilled with seawater/gel/Lignosulphonate mud.

The Sele Formation had thin stringers of sand with oil shows, but no significant Paleocene sands were developed above the Heimdal Formation in this well. Massive Paleocene Heimdal Formation sands were encountered at 1784.5 m (1759.5 m TVD MSL) and 1860 m (1835 m TVD MSL). The upper sand is 65 m thick and had oil shows evident by sidewall cores at 1785 m and 1786 m. The lower sand is 20 m thick and was entirely water-bearing with no shows. The Balder Field oil/water contact is generally thought to be at 1785 m (1760 m).

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

The well was permanently abandoned on 7 May 1981as a dry well with shows.

Testing

No drill stem test was performed.

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