The estimated size of the Bozhong 26-6 field is an 'oil in place' metric, referring to the total volume in a reservoir rather than the recoverable portion of that, the company told Reuters.
The discovery well was drilled to a depth of 4,480 metres (14,698 ft), and encountered 321.3 metres of oil pay zones, meaning they have the potential to be extracted economically.
The well was tested to produce an average of around 2,040 barrels of crude and 11.25 million cubic feet of natural gas per day, the company stated.
The southern Bohai Sea has an average water depth of 22 metres, the company added.
State-owned CNOOC is China's largest offshore oil and gas producer. It has targeted a record 650 million to 660 million barrels of oil equivalent (boe) for this year.
(Reporting by Andrew Hayley; Editing by Tom Hogue, Nivedita Bhattacharjee and Barbara Lewis)
