Wellesley Petroleum AS, an exploration company focused on the Norwegian Continental Shelf (NCS) on Oct. 29 announced the successful appraisal of the Grosbeak Discovery in the Northern North Sea by wells 35/11-21S and 35/11-21A. The wells were drilled in production license Pl248I where Wellesley holds a 60% operated interest.
Well 35/11-21S encountered a gross oil column of 90 meters at the target Middle Jurassic Brent Group level. Within this oil column are 45 meters comprised net reservoir with good to excellent reservoir properties. Extensive data was acquired from the reservoir interval including a successful well test which confirmed the high quality and good connectivity of the reservoir.
Sidetrack well 35/11-21A encountered 20 meters of excellent quality gas-bearing reservoir and an 8 meter oil column in the shallower Upper Jurassic Sognefjord and Fensfjord formations.
The underlying Brent Group reservoir comprised a 50 meter oil column in the Ness Formation with 9 meters of sandstones lying within the oil zone. Pressure data from these sandstones indicates good connectivity to the zone tested in the 35/11-21S well.
The updated range of recoverable resources in the Grosbeak Discovery is 53 – 115 million barrels of oil plus 269 - 432 billion cubic feet of gas. The 35/11-21S and A wells have been plugged and abandoned and development studies will commence.
“This is a very positive end to our operated drilling campaign in the Grosbeak area,” said Wellesley Group CEO Chris Elliott. “Our pre-drill subsurface studies of Grosbeak indicated that the Brent Group sandstones were both predictable and well connected and this has been demonstrated by the appraisal wells, significantly reducing the development risk of this reservoir. The discovery of a separate, excellent quality gas reservoir in the Upper Jurassic also adds significant resources to what we expect to be a material and commercially robust future development.”