China National Offshore Oil Corp.(CNOOC) Ltd., China's largest offshore oil producer, said Thursday that production has started at two of the company's newest oil fields in the South China Sea.

One of the fields now has four wells in operation with a peak daily output of 3,960 barrels, CNOOC said in a statement.

The other field currently has nine operational wells and is expected to achieve a peak daily output of 5,870 barrels in 2013, the statement said.

The company aims to meet a production target of 330 to 340 million barrels of oil equivalent this year.

Production in the first half totaled 160.9 million barrels, down 4.6 percent year on year, according to the company's semi-annual report.