The estimate of recoverable reserves in Statoil’s subsea Vigdis extension development has been upgraded by eight to 12 million barrels of oil.
At today’s oil prices, this increase enhances the value of the North Sea project by up to NOK 2.5 billion.
“Drilling and completion of the first two production wells confirmed our expectations as to additional volumes in both wells,” says Stein Storli, reservoir development manager for Vigdis.
He reports that extensive geophysical work in parallel with the project has provided detailed mapping of the sub-surface as well as an optimum well placement and drainage strategy.
This strategy is expected to yield a recovery factor of about 60 per cent, which is above Statoil’s performance target for subsea developments.
“We’ve learn a lot of valuable lessons from this work,” says Mr Storli. “It was presented at an international geophysical congress in 2002 as an example of successful mapping.”
The two first Vigdis extension wells came on stream in October, more than two months ahead of schedule.
And at just under NOK 2.6 billion, the cost of this development is roughly NOK 400 million below its original budget.
Preliminary estimates show that, with the upgrading in reserves, the development should provide some 60 million barrels of additional oil from the Vigdis satellite.
Tapping a structure called Borg North-West, which was proven in 1994, the extension project embraces four subsea installations and six wells.
It will strengthen the profitability of Vigdis, which is tied back to Statoil’s Snorre A platform.