ID: 292
OBJECTID: 292
wlbNpdidWellbore: 297
wlbName: 7/12-3 A
wlbHistory:

General

Well 7/12-3 A is a geological sidetrack to 7/12-3 on the western flank of the 7/12-2 Ula discovery in the North Sea. The primary objective was to establish the oil-water level in the Ula structure.  

The well is type well for the Mandal Formation.

Operations and results

On 4 June 1977 appraisal well 7/12-3 A was kicked off from below the 13 3/8” casing shoe in well 7/12-3 at a depth of 1720. The semi-submersible installation Norskald drilled the well to TD at 4191 m (4011 m TVD) in the Permian Zechstein Group.

Well 7/12-3A penetrated the reservoir at 3638.5 (3506.8 m TVD). The cores showed oil staining, cut and fluorescence. Wire line logs and testing showed this to be immovable oil, and indicated an oil water transition zone to a depth of 3693.5. (3555.3 m TVD). One hundred and eighty-nine meters of Ula Formation reservoir were encountered representing a true thickness of 168.9 m, and a net to gross ratio of 0.83 assuming a 10% porosity cut off on the computer-processed log.

Seven full hole cores were cut from 3642.0 to 3730.0 m. RFT fluid samples were taken at 3675.5 m (salt water and mud filtrate) and 3688.5 m (salt water with traces of gas and oil/oil-water emulsion).

The well was permanently abandoned on 6 September 1977 as a dry well with shows.

Testing

DST 1 tested the interval 3771.0 to 3715.5m. The test flowed 192 m3 saline formation water /day through a 32/64 choke. The DST temperature was 146.7 °C.

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