GODALMING, UK – The semisubmersible Transocean Spitsbergen has completed operations on an exploratory well on the Halifax structure west of Shetland.
OperatorHurricane Energy says the well discovered oil, with early analysis suggesting it is linked to the nearby basement Lancaster field, forming a single large hydrocarbon accumulation.
The 1-km (0.6-mi) oil column was significantly below local structural closure, Hurricane added, while the reservoir interval encountered is pervasively fractured with porosities similar to those at Lancaster.
Deeper oil down to 1,846 m (6,056 ft) TVD subsea , compared with an oil water contact (OWC) at Lancaster at 1,678 m (5,505 ft) TVDSS, is most likely caused by a tilted OWC.
The Halifax well was drilled and cased to 1,179 m (3,868 ft) TVDSS: it was designed to isolate a potential gas cap and oil-bearing column to a depth of 100 m (328 ft) true vertical thickness below structural closure.
It was subsequently drilled to 1,801 m (5,909 ft) TVDSS and a drillstem test was performed, but due to a combination of budget constraint, available time, and the safety requirement of drilling overbalance, clean up could not be achieved, so only traces of formation oil could be retrieved to surface.
The well was finally TD’ed at 2,004 m (6,575 ft) TVDSS, with no confirmed OWC encountered.
Following discussions with Britain’s Oil & Gas Authority, the well has been suspended to allow for potential future operations, involving deepening and/or further testing. Hurricane will determine the program following analysis of the well results.
CEO Dr. Robert Trice said: “We believe that the GLA [Greater Lancaster Area] is a single hydrocarbon accumulation, making it the largest undeveloped discovery on the UK continental shelf.”
Dr. Trice added that a final investment decision for the Lancaster early production system remains on track for mid-year.