China National Offshore Oil Corp Ltd, the country's biggest marine oil producer, said on Tuesday that its net production in the first quarter declined by 6.3 percent year-on-year to 79.8 million barrels of oil equivalent, due to the suspension of production at the Penglai 19-3 oilfield.

But the company remains confident that it will realize its previous target of 330 to 340 million barrels of oil equivalent throughout 2012, as four new projects are expected to become operational this year to offset losses from Penglai 19-3, said Zhong Hua, CNOOC chief financial officer.