Energean Oil & Gas, Greece's only oil producer, raised on Thursday its estimate of recoverable oil deposits by more than 10 percent to 30 million barrels.
Energean, in which US hedge fund Third Point LLC holds a 44.5 percent stake, produces about 1,700 barrels of crude a day off the northern Greek island of Thassos.
That output covers only a negligible part of the country's energy needs. Debt-laden Athens has embarked on an ambitious program to discover big hydrocarbon reserves in the country's west.
The Thassos oil production, which began in 1981, was moribund when Energean took it over in late 2007. By using new technology to squeeze more crude out of the old deposit, it has raised recoverable reserves from 2 million barrels to 15 times that volume.
"Production from the Gulf of Kavala (Thassos) will continue for at least a further 15 years," the company's Chief Executive Matthios Rigas said in a statement. Energean and its predecessors have produced about 113 million barrels of oil in the region over the past 33 years.
The only other proven oil deposit in Greece is at Katakolon, in the country's south, with a volume of 5 million barrels. [Reuters]