18/11-1

General

Well 18/11-1 is located on the Stavanger Platform, ca 25 km north of the Yme Field in the North Sea. The primary objective was to test possible hydrocarbon accumulation in Middle Jurassic sandstones in a seismic structure interpreted on the same trend as the 17/12-1R Bream Discovery. Secondary objectives were possible Triassic or Rotliegendes sandstones in a faulted triangular block tilted southwest. Planned TD was 150 -200 m below the primary target, prognosed at 2365 m.

The well is Reference Well for the Sandnes Formation.

Operations and results

Wildcat well 18/11-1 was spudded with the semi-submersible installation Deepsea Driller on 17 February 1974 and drilled to TD at 2086 m in Pre-Devonian Basement rocks.

Late Cretaceous limestones from 498 m to 985 m had excellent reservoir properties. Limestones below this level became harder; more compacted, and had poor reservoir properties. The well penetrated top Sandnes Formation at 1878 m with fine, argillaceous cemented, well sorted sandstone down to 1919 m, and a Bryne Formation sequence with fine to coarse, angular grained, sandstones with variegated shale from 1964 m to 2060 m. The Jurassic sands rested directly on basement at 2060 m. No noticeable shows were recorded in the well. Organic geochemical analysis proved a thermally immature well all through down to basement (%Ro < 0.36). Good source potential (TOC in the range 1.3 % to 6 % and Hydrogen Index from 30 to 230 mg HC/g rock was seen in a ca 80 m thick Kimmeridgian shale sequence from 1735 m. High TOC in the range 1.3 % up to 6.9 % was seen also below 1919 m in Callovian claystones, but Hydrogen Index in the range 30 - 180 mg HC/g rock suggested a more inertinitic, gas prone kerogen in this sequence.

One conventional core was cut at TD from 2082 m to 2086 m. No fluid samples were taken.

The well was permanently abandoned on 31 March 1974 as dry hole.

Testing