Output from Statoil's Statfjord field in the North Sea will stay high enough to keep all three platforms working for another five-six years at least.
This conclusion comes in a study of the late production phase recently completed by the licensees. It means that operations will remain unchanged for the next few years.
The alternative was to convert Statfjord B to a simple treatment platform, and transfer its oil and gas output by flowline to the A installation for processing.
That solution would have sharply reduced operating costs, says Kåre Søvik, who headed work on the study.
But calculations show that the present mode of operation will yield the best overall economics on the field for several years to come.
If the B platform no longer had any processing capacity, it would be necessary to reduce production from Statfjord for a period.
This cut-back, combined with the cost of conversion, means that such an approach would not be economic overall compared with leaving things as they are.
"The flowline option would not be relevant until five-six years from now," explains Mr Søvik. "This mode of operation might then help to keep the field profitable for long enough to bring the total recovery factor up to a unique 70 per cent."
He adds that gas production could play an increasingly important role for Statfjord. The licensees will now be surveying its ability to produce gas in the late phase.
According to Mr Søvik, tail production from Statfjord must be seen in a broader context. Satellite fields tied back to these installations and all operations in the surrounding Tampen area as a whole have to be taken into account when deciding the most profitable mode of operation at any time.