16/1-31 S

General

Well 16/1-31 S was drilled to test the Jorvik prospect on the Utsira High, about 4 kilometres northeast of the Edvard Grieg platform in the North Sea. The primary objective was to prove oil in conglomerates from the Triassic Age in an extension of the Edvard Grieg basin toward the east.

Operations and results

Appraisal well 16/1-31 S was spudded with the semi-submersible installation Leiv Eiriksson on 10 March 2019 and drilled to TD at 2220 m in conglomerates of indeterminate Triassic to Permian age. Operations proceeded without significant problems. The well was drilled with seawater and hi-vis pills down to 602 m and with Polymer water-based mud from 602 m to TD.

The well penetrated the Early Cretaceous Åsgard Formation directly overlying top of the target reservoir at 1938 m (1866.4 m TVD). The reservoir contained an oil column of about 30 metres in conglomerates and conglomeratic sandstones, presumably of Triassic Age and with generally poor reservoir quality. There was around one metre of sandstone of good quality in the upper part of the reservoir section. The oil/water contact was not proven. Pressure measurements showed that the area is in communication with the Edvard Grieg field. The reservoir pressure was depleted 9-10 bar compared to the Edvard Grieg before start of production.

Below 1968 m and down to 2028 m shows are described on cores as: faint to moderate odour, 40% patchy weak, dark yellow direct fluorescence, slow blooming good bluish white cut fluorescence, 30% moderately, cream fluorescent residue. Patchy shows (cut and fluorescence) was described on sidewall cores down to 2176.5 m.