Wintershall discovers hydrocarbons south of Vega field
Wintershall Dea Norge AS discovered gas, condensate, and oil in Cuvette well 35/11-27 S in production license (PL) 248 in the North Sea, and is considering tying the find to existing infrastructure.
The well, which lies 100 km southwest of Florø and 3 km south of Vega field, resulted in discoveries in four different formations.
Cuvette was drilled to a vertical depth of 3,986 m subsea in 378 m of water by the Transocean Norge rig. It was terminated in the Rannoch formation in the Middle Jurassic.
The primary exploration target was to prove petroleum in Middle Jurassic reservoir rocks in the Tarbert and Upper Ness formations. The secondary target was to prove petroleum in sandstones from the Upper Jurassic.
The well encountered a gas-condensate column totaling 55 m in the Tarbert and Upper Ness formations, about 29 m of which were sandstones of moderate-to-poor reservoir quality. The gas-water contact was not encountered.
The well also proved a 5-m oil column in the Etive formation in the Middle Jurassic, 4 m of which consist of sandstones with poor-to-moderate reservoir quality. The oil-water contact was encountered 3,843 m below sea level.
In the secondary exploration target in the Upper Jurassic, the well encountered two petroleum-bearing sandstone intervals. In the uppermost interval, the gas-condensate column is 8 m, of which 5 m consists of sandstones with poor reservoir properties. The gas-water contact was not encountered.
In the lowermost interval, a gas-condensate column totaling 16 m was encountered, of which 14 m were in sandstones with poor-to-moderate reservoir quality. The hydrocarbon-water contact was encountered at 3,327 m below sea level.
The well was not formation-tested, but extensive data acquisition and sampling have been conducted. The well will now be plugged.
An oil zone was also encountered in the Etive formation. As of now, there is no preliminary volume estimate. An additional interval in the Upper Jurassic was also encountered during the drilling operation.
The preliminary estimate of the size of the discovery in the Tarbert and Upper Ness formations is 1.5-3.5 million cu m of recoverable oil equivalent (9-22 MMboe). The preliminary estimate discovery in the Upper Jurassic is 1.1–2.6 million cu m of recoverable oil equivalent (7-16 MMboe).
Wintershall Dea is operator at PL 248 with 60% interest. Petoro AS holds the remaining 40%.
Alex Procyk | Upstream Editor
Alex Procyk is Upstream Editor at Oil & Gas Journal. He has also served as a principal technical professional at Halliburton and as a completion engineer at ConocoPhillips. He holds a BS in chemistry (1987) from Kent State University and a PhD in chemistry (1992) from Carnegie Mellon University. He is a member of the Society of Petroleum Engineers (SPE).
