Basic earnings per share were RMB 0.88, and an interim dividend of HK$0.25 per share was declared, according to the company's interim report.
The company's revenue rose 51% year on year to RMB 124.57 billion in the first half. Sales of oil and natural gas jumped RMB 45% year on year to RMB 97.03 billion during the period.
In the first six months, the company's output of oil and natural gas grew 12.9% year on year to 168.7 million barrels of oil equivalent, mainly boosted by contributions from new oilfields and wells, and projects acquired in 2010.
CNOOC saw its oil price rise 40.8% year on year to US$108.16 per barrel and natural gas price rise 15.5% to US$4.92 per cubic foot in the first half.