Wellesley upgrades North Sea Grosbeak reserves after appraisal drilling

Offshore staff

STAVANGER, Norway – The semisubmersible Transocean Arctic has successfully appraised the 2009 Grosbeak discovery in the northern North Sea for Wellesley Petroleum after drilling two wells in license PL248I.

Well 35/11-21S encountered a gross oil column of 90 m (295 ft) in the Mid-Jurassic Brent Group interval, of which 45 m (147.6 ft) comprised net reservoir with good reservoir properties.

Data acquired from the reservoir interval included a well test that confirmed the quality and connectivity of the reservoir.

Side track well 35/11-21A intersected 20 m (65.6 ft) of good-quality gas-bearing reservoir and an 8-m (26-ft) oil column in the shallower Upper Jurassic Sognefjord and Fensfjord formations.

The underlying Brent Group reservoir comprised a 50-m (164-ft) oil column in the Ness formation with 9 m (29.5 ft) of sandstones lying within the oil zone. Pressure data from these sandstones indicates good connectivity to the zone tested in the earlier well.

Grosbeak is in 360 m (1,181 ft) of water, 10 km (6.2 mi) northeast of the Fram field. Wellesley estimates recoverable resources in the range of 53-115 MMbbl of oil and 269-432 bcf of gas. Both wells have been P&A’d and development studies will begin.

CEO Chris Elliott said: “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.”

Wellesley assumed operatorship of the license early this year.

TheTransocean Arctic will now drill wildcat well 30/6-30 in northern Norwegian North license PL825 for Faroe Petroleum.

10/29/2018