German oil firm Wintershall has made a minor discovery near the Vega field in the Norwegian North Sea, according to the Norwegian Petroleum Directorate.
The discovery was made as part of a four-well drilling campaign in production license 248 F, using the Borgland Dolphin semisubmersible in 373m water depth.
Well 35/11-20 B was drilled to further delineate the oil discovery in intra Heather formation sandstone and prove petroleum in Middle Jurassic (Brent group) and Early Jurassic (Cook formation) reservoir rocks.
The well encountered a total oil column of 46m in intra Heather formation sandstone, of which 29m were of moderate reservoir quality. A total oil column of 19m was encountered in the Tarbert formation in the Brent group, of which 10m were of moderate reservoir quality. The Cook formation was encountered with a total thickness of about 170m with predominantly poor reservoir quality and only traces of petroleum.
Preliminary estimates place the size of the discovery between 1.5 and 4.5 MMcm of recoverable oil equivalents. The licensees will evaluate the discovery along with other nearby discoveries with a view toward a potential development.
The primary and secondary exploration targets for well 35/11-20 S were to prove petroleum in Late Jurassic reservoir rocks (intra Heather formation sandstone).
The well did not encounter reservoir rocks in the primary exploration target. Poor reservoir quality rocks were encountered in the secondary target.
The objective of well 35/11-20 A was to delineate the oil discovery in intra Heather formation sandstone, and to prove petroleum in Middle Jurassic (Brent group) and Early Jurassic (Cook formation) reservoir rocks.
The well encountered a total oil column of 33m in intra Heather formation sandstone, of which 19m were of good reservoir quality. Due to technical issues, it was not possible to reach the Brent group and Cook formation.
The wells were drilled about 5km southeast of the Vega field in the North Sea and 100km southwest of Florø region, Norway.