8/3-2

General

Well 8/3-2 is located in the Egersund Basin in the North Sea. The primary objective of 8/3-2 was to test possible hydrocarbon accumulations in sandstones of Middle Jurassic and Triassic sandstones.

Operations and results

Wildcat well 8/3-2 was spudded with the Semi-submersible installation West Vanguard on 4 October 1982 and drilled to TD at 2657 m in the Triassic Skagerrak Formation. This was the first well drilled by West Vanguard. Drilling of the 36" and 26" sections were without incident, however the BOP stack required extensive repair and eight days were spent waiting on parts and repairs. Gumbo caused some delay in the 17 1/2" section. The well was drilled with spud mud down to 501 m, with polymer/gypsum mud from 501 m to 1150 m, and with gel/lignosulphonate mud from 1150 m to TD. The well encountered Middle Jurassic (Bryne Formation) sandstones with good reservoir properties from 2375 m to 2417 m.

This was thinner than expected. A thin sandstone sequence was encountered from 2465 m to 2474 m in the underlying Skagerrak Formation. Some shows were recorded in shales from the interval 2088 m to 2355. The lower part of the Tau Formation is a "hot shale" characterized by very high gamma ray readings. No shows were seen in the porous sections and electrical logs and RFT pressure gradients confirmed water wet reservoirs. Organic geochemical analyses proved excellent source rock potential in the Late Jurassic shales, with TOC in the range 2 % to 7 % and hydrogen index in the range 250 to 600 mg HC/g TOC. Best potential is seen in the Tau Formation. The well is immature for oil and gas generation with %Ro = 0.45 - 0.5 towards TD. The analyses indicate shows of wet gas in the Bryne Formation sandstones, but otherwise confirm the shows recorded during drilling. Two conventional cores were taken in the interval 2384 m to2397.3 m in the Bryne Formation. No fluid samples were taken.

The well w