Centrica said preliminary appraisal results of its Butch exploration well indicate a discovery of 30 million-60 million barrels of oil equivalent.
Jonathan Roger, managing director of upstream activity at Centrica, said the suggestion that there is light oil off Norway's coast is positive news for his company.
"This discovery comes only two weeks after announcing the $1.5 billion acquisition of production and development assets from Statoil, which opens up new exploration possibilities and will increase our reserves by nearly a third," he said in a statement.
Centrica, parent company of British Gas, announced it signed a strategic agreement with Statoil for the supply of 17 trillion cubic feet of natural gas for British consumers.
British Energy Secretary Chris Huhne, in a statement, said the 10-year deal was a milestone for British energy security.
The Butch well is about 135 miles off the coast of Norway. Centrica said further data collection is under way to assess the find.