16/1-34 S

General

Well 16/1-34 S is located on the Utsira High, north of the Edvard Grieg Field in the North Sea. It was drilled to appraise the oil-leg in the 16/1-6 S Heimdal Formation Verdandi discovery. Grid Formation injectite sandstones and expected clastic formations of Jurassic age (Garun lead) were secondary targets.

Operations and results

Wildcat well 16/1-34 S was spudded with the semi-submersible installation Deepsea Stavanger on 7 July 2021 and drilled to TD at 2383 m (2125.7 m TVD) m in the Late Triassic Raude Formation. The well was drilled S-shaped with a vertical section down to 543 m, up to ca 40 deviation at most, then dropping to 21 deviation in the bottom section. Operations proceeded without significant problems. The well was drilled with seawater and hi-vis pills down to 543 m, with Rheguard Prime oil-based mud from 543 m to 2016 m and with Glydril Plus mud from 2016 m to TD.

In the Heimdal Formation, wellbore 16/1-34 S encountered an oil column of approximately 7 m in good quality reservoir sandstone with a total thickness of 50 m. The oil-water contact was found at 2090.2 m (1850.5 m TVD). Fluid sampling showed good quality oil. However, pressure data in the following 16/1-34 A sidetrack encountered Heimdal in a different pressure segment to the Verdandi gas discovery and consequently the 16/1-34 S oil discovery is considered to represent a separate accumulation which is not in direct contact with the Verdandi gas accumulation. This is referred to as the Lillefix discovery. The Grid Member consists of two sandstone intervals. The upper sandstone is about 8 m thick and is filled with hydrocarbons. The fluid gradient in this sandstone could not be established. The lower sandstone is about 70 m thick and is water filled.