2/2-2

General

Well 2/2-2 was located near the crest of an elongated salt-induced domal structure in the NW corner of the block. The main target was the Late Jurassic Ula Formation shallow marine sandstone. Sandstones of Middle Jurassic and Late Triassic age were possible secondary targets, having the same structural definition as the Ula sand. Secondary objectives were further represented by the Late Cretaceous chalk and a sandstone of Oligocene age.

According to the license agreement, the well should be drilled into the Triassic, salt or a maximum depth of 5000 m whatever came first. The well reached a TD of 3124 m in Permian anhydrites thus fulfilling the work commitment.

Operations and results

Well 2/2-2 was spudded with the semi-submersible installation Dyvi Alpha on 4 April 1992 and drilled to TD at 3124 m in the Late Permian Zechstein Group. When drilling the 36" hole, the pipe stuck. After the pipe was worked free, the drilling continued. The well took a kick at 2425 m. The well was drilled with seawater and bentonite down to 715 m, with polymer/gypsum/"SST 202" mud from 715 m to 1965 m, and with lignite mud from 1965 m to TD.

The well penetrated porous layers in the Oligocene, the Cretaceous and the Jurassic. A full suit of logs was run in these sections. In the interval 1978-2057 m of the Oligocene, a bioturbated and cross-laminated very fine sandstone, interbedded with siltstone and shale was found (the Vade Formation). The upper part of the sand was found gas bearing from 1978 m down to a GWC at 2002 m. Net pay thickness was 14 metres. A segregated RFT gas sample was taken at 1996.4 m. The sand has a porosity of 24% with a shale content of 25%. A water saturation of 40% was estimated. The core analysis gave an average porosity of 27 %, but this is probably too high because the core-plugs were drilled mainly in clean silt/sandstone intervals. Below the gas water contact, a net sand thickness of 13 m w