Statoil has commissioned Kvaerner for a concept study on a slim-leg wellhead platform that could be used instead of tied-back subsea wells in future development of 25-year-old Oseberg oil field offshore Norway.
The concept is for a standardized, unstaffed, dry-tree platform focusing on minimization of facilities, equipment, and costs.
The platforms would be installed in water as deep as 150 m.
A Kvaener press statement said the concept “may be a cost-effective solution compared to a conventional subsea tie-back solution.”
It said the platforms would be compatible with new generations of jack up drilling rigs.
Last year, Statoil let contracts to Samsung Heavy Industries Co. Ltd. to build, and KCA Deutag Drilling Norway AS to operate tailor-made jack ups optimized for drilling and completing subsea wells in Oseberg and Gullfaks fields, both in the Norwegian North Sea (OGJ Online, June 4, 2013).
Oseberg has produced 1.7 billion bbl of oil from reserves originally estimated at 1 billion bbl. Statoil now estimates ultimate recovery at 2.6 billion bbl.
Application of new drilling technology and extensive gas injection have pushed the recovery rate from Oseberg’s main reservoir, a Middle Jurassic sandstone in the Brent group, to 69%.