U.K.-based i3 Energy discovered about 200 million barrels (MMbbl) of oil in its Serenity prospect in the British North Sea and plans to coordinate its development with Repsol Sinopec Resources UK, which operates the neighboring Tain Field, i3 said on Oct. 29.

The company is already in talks to use the Repsol Sinopec’s Bleo Holm FPSO to exploit about 63 MMbbl in its Liberator Field at a rate of 20,000 barrels per day, it said.

Although an unsuccessful well shrunk a previous plan for that initial development of Liberator targeting about 90 million barrels, i3 still expects the whole area could yield about 390 MMbbl separately from the Serenity area.

The company said it can fund development of Serenity and any future enlargement of the Liberator projects with cash flow from its initial production at Liberator, but it is also considering selling part of its 100% stakes in the fields.

RockRose owns half of the Tain Field and expects a final investment decision for the field in the second half of next year.

Swiss asset manager Lombard Odier is i3’s biggest shareholder at about 9%.