Wintershall Dea makes gas and condensate discovery in the North Sea

The well resulted in discoveries in four different formations.

The preliminary estimate of the size of the discovery in the Tarbert and Upper Ness formations is between 1.5 – 3.5 million Sm³ of recoverable oil equivalent. This corresponds to 9 – 22 million boe.

The preliminary estimate of the size of the discovery in the Upper Jurassic is between 1.1 – 2.6 million Sm³ oil equivalent. This corresponds to between 7 – 16 million boe.

An additional interval in the Upper Jurassic was also encountered during the drilling operation.

An oil zone was also encountered in the Etive Formation. As of now, there is no preliminary volume estimate here.

The Transocean Norge rig drilled the well, 3 km south of the Vega field.

The licensees are considering tying the field back to existing infrastructure in the area.

Geological information

The primary exploration target for the well was to prove petroleum in Middle Jurassic reservoir rocks in the Tarbert and Upper Ness formations.

The secondary exploration target was to prove petroleum in sandstones from the Upper Jurassic.

Well 35/11-27 S encountered a gas/condensate column totalling 55 m in the Tarbert and Upper Ness formations, around 29 m of which was 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 3843 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 consist of sandstones with poor reservoir properties. The gas/water contact was not encountered.

In the lowermost interval, a gas/condensate column totalling 16 m was encountered, of which 14 m in sandstones with poor to moderate reservoir quality. The hydrocarbon/water contact was encountered at 3327 m below sea level.

The well was not formation-tested, but extensive data acquisition and sampling have been conducted.

Well 35/11-27 S was drilled to a vertical depth of 3986 m below sea level and was terminated in the Rannoch Formation in the Middle Jurassic.

Water depth at the site is 378 m. The well will now be permanently plugged and abandoned.

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