7121/5-3

General

Well 7121/5-3 is located southeast of Snøhvit and northeast of Albatross in the Hammerfest Basin in the Troms I area. Block 7121/5-3 is characterised by a set of east-west running faults cutting Middle Jurassic sediments. The main objective of well 7121/5-3 was to prove hydrocarbons in the "Delta" prospect sandstones of the Nordmela and Stø Formations of Early to Middle Jurassic age.

Operations and results

Wildcat well 7121/5-3 was drilled with the semi-submersible installation "Transocean Arctic". First, a 9 7/8" pilot hole was drilled from sea bed to 967 m. On 16 February 2001 well 7121/5-3 was spudded 24 m WNW of the pilot hole and drilled to a total depth of 2265 m in rocks of Late Triassic age (Snadd Formation). The well was drilled with seawater and bentonite down to 967 m, and with "GLYDRIL" mud with glycols from 967 to TD. In the "GLYDRIL" section the mud was a mixture of new and re-used mud from a previous well. MWD logs in the pilot hole showed that only Palaeocene and possibly Eocene sediments were preserved in the Tertiary section. Only a thin glaciomarine Quaternary sequence was present in the well. Good reservoir zones were recorded in the Stø, Nordmela and Tubåen Formation sandstones. The sand sequences of these formations proved to be water bearing. This was verified by interpretation of logs and MDT pressure measurements, though weak to good shows were recorded in cores from the reservoir intervals. Two cores were cut, the first in the Stø Formation sandstone and the second in the Tubåen Formation sandstone. Two water samples were taken, the first in the Stø Formation at 1881 m MD and the second in the Tubåen Formation at 1991 m MD. The well was permanently abandoned as a dry well with shows on 9 March 2001.

Testing

No drill stem test was performed.