Total, acting on behalf of a partnership with State Oil Co. of Azerbaijan Republic and French energy company GDF Suez, said the step was an important milestone for the Absheron block.
The French supermajor said well results suggest the discovery holds at least 5.2 trillion cubic feet of non-associated gas with condensates. The cumulative net pay of the Absheron find was measured at roughly 525 feet thick.
"This declaration of commerciality is the result of the success of our more aggressive exploration program and our desire to bring discovered hydrocarbons rapidly into production," said Yves-Louis Darricarrere, president of the exploration and production branch of Total, in a statement.
Absheron is located about 60 miles southeast of Baku in the Azeri waters of the Caspian Sea. Total said the first phase of development could proceed with a limited number of wells.
Europe views natural gas reserves in the Caspian Sea as vital for its energy security plans. Last week, a BP-led consortium developing the Shah Deniz II project chose Nabucco West as a potential pipeline to carry natural gas to Europe. Nabucco West is part of the Southern Corridor, a network of pipelines meant to move Europe away from Russian natural gas supplies.