ID: 49
OBJECTID: 49
wlbNpdidWellbore: 50
wlbName: 7120/8-2
wlbHistory:

General

The 7120/8-2 well was drilled on the Alpha-South structure in the Western part of the Hammerfest Basin. The first well in the block, well 7120/8-1, was drilled on the Alpha North closure in 1981, north of the major east - west fault splitting the two closures/structures. This well found gas-bearing sandstones in the Middle to Early Jurassic. The primary objective of well 7120/8-2 was to test possible hydrocarbon accumulations in sandstones of Middle to Early Jurassic age (Stø Formation) in the Alpha-South structure.

Operations and results

Well 7120/8-2 was spudded with the semi-submersible installation Neptuno Nordraug on 15 April 1982 and drilled to TD at 2590 m in Late Triassic sediments (Fruholmen Formation). The drilling of the 36" and 26" hole went forth without any problems. After this several problems occurred and 78 days were used to reach TD, 29 days more than programmed. The main hang-ups were: broken 20" csg, partly collapsed 13-3/8" csg, pulled BOP stack, roller system, and stucked stabilizer at 2156 m. The well was drilled with gel/spud mud down to 333 m, with gel/seawater from 333 m to 752 m, and with gel/lignosulphonate/seawater from 752 m to TD.

Hydrocarbon accumulations were discovered in sandstone sequences between 2081-2161 m in the Stø Formaton. The reservoir sandstones showed good to excellent reservoir properties. Gas composition from the DST was almost identical to the gas composition of the DSTs performed in the 7120/8-1 well. This was also indicated by gas gradients established from the RFT pressure points taken in the two wells. RFT pressure points from the two wells also indicated that the water zone most likely is in communication. Organic geochemical analyses show TOC in the range 0.7 % to 2.8 % TOC in mudstones from the Early Cretaceous. The kerogen in these samples are Type IV / III with a poor potential, increasing to fair at the base, for gas. Olive black claystones o
wlbHistoryDateUpdated: 2016-05-19T00:00:00