Statoil's exploration campaign off Britain yielded one discovery, one dry well and one non-commercial discovery this year, the company said on Monday.
Results of the Mariner Segment 9 and Jock Scott wells were disappointing, while the third, a sidetrack to Statoil (STO)
's Verbier well in the outer Moray Firth, proved at least 25 million barrels of oil.
"Whilst the results of the other two exploration wells were disappointing, we are convinced of the remaining, high-value potential on the UK continental shelf," Jenny Morris, Statoil's vice president for UK exploration, said in a statement.
"The Verbier result certainly gives us the confidence and determination to continue our exploration efforts," she added.
The preliminary results suggest that the Verbier discovery could hold from 25 million to 130 million barrels, but more drilling will be needed to refine the range and potential for commercial development, Statoil said.
Statoil holds 70 percent in the license, Jersey Oil and Gas 18 percent and CIECO Exploration and Production (UK) 12 percent.
At the Mariner well, where non-commercial quantities of hydrocarbons were found, Statoil's partners were JX Nippon, Siccar Point Energy and Dyas, while the dry Jock Scott well was a partnership with BP (BP). (Reporting by Nerijus Adomaitis