ID: 169
OBJECTID: 169
wlbNpdidWellbore: 173
wlbName: 25/8-1
wlbHistory:

General

Well 25/8-1 was drilled on the Utsira High in the North Sea. The main purpose was to test an Eocene structural closure, up dip from oil-bearing Eocene sands in Well 25/11-1.

Operations and results

Wildcat well 25/8-1 was spudded with the vessel Glomar Grand Isle on 28 April 1970. Drilling operations were normal down to 2606 m, which became TD in the well, 289 m into the Early Permian Undefined Group. While drilling at this depth the drilling pipe parted. After recovering the upper portion of the drill pipe the top of the portion left in the hole was found to be at 2559. Attempts to recover the fish failed and after logging and taking sidewall cores in the uncased hole the well was prepared for testing. Initial drilling from the sea floor to 378 m was with sea water and gell. Below 378 m to 1311 m, the mud system consisted of sea water, spersene XP-20 salinex. From 1311 m to TD fresh water, spersene XP-20 mud was used.

The well penetrated several Tertiary sands above the Paleocene (Utsira and Skade Formations). These sands were water wet, but some methane was recorded in the upper part of the Utsira Formation.Two Paleoocene sands (Hermod Formation at 1754.4 - 1758.1 m and 1759.0 - 1763.0 m) were found. The sands were separated by a thin 1 m shale section. Upon testing, the sands were found to be capable of producing approximately 429 Sm3 of 21.7 deg API gravity, low sulphur (0.77 to 0.80%) oil per day. All other sands or reservoirs penetrated by the well, including the Heimdal Formation at 1777 to 1812 m, were water wet without shows.

Seven cores were cut in the well. Core no 1 was cut from 1676.4 to 1684.9 m in the Balder Formation, cores no 2 t
wlbHistoryDateUpdated: 2019-06-11T00:00:00