16/5-8 S

General

Well 16/5-8 S was drilled to test the Goddo prospect on the Utsira High in the North Sea. The primary objective was to prove hydrocarbons in porous/fractured basement below base Cretaceous and to verify pressure communication with the nearby Rolvsnes discovery.

Operations and results

Wildcat well 16/5-8 S was spudded with the semi-submersible installation Leiv Eiriksson on 8 July 2019 and drilled to TD at 2468 m (2093 m TVD) 268 m into granitic Basement rock. No shallow gas was identified in the site survey or while drilling the well. Operations proceeded without significant problems. The well was drilled with seawater and hi-vis pills down to 196 m, with KCl/polymer mud from 196 m to 620 m, and with BaraHib ECO water-based mud from 620 m to TD.

Top Basement was penetrated at 2201.7 m (1889.4 m TVD), underlying Valanginian age Åsgard Fm marls. The basement is porous and fractured with a ca 20-25 m oil column. Pressure data shows that the Goddo discovery is not in pressure communication with the Rolvsnes oil discovery. There were no oil shows outside of the hydrocarbon bearing fractured basement zone in the well.

Five continuous cores were cut in the interval 2192 to 2229.8 m. Recovery was 99 to 100% for all cores except core no 2 from 2201 to 2206 m, which had a recovery of 79.2%. The average core to log shift is estimated to +2.03 m with +1.76 m at the BCU /top Basement level in core no 1. Wire line FTNG fluid samples were taken at 2202.64 m (oil), 2205.38 m (oil), 2205.71 m (oil), 2246.16 m (water), and 2251.46 m (water). PVT analysis of the oil samples gave GOR around 150 Sm3/Sm3 and an oil density of ca 0.872 g/cm3.

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