BEIJING - China's largest offshore oil and natural gas developer's 2015 net profits slumped 66.4 percent year on year due to lower oil prices, the company said on Thursday.

China National Offshore Oil Corporation (CNOOC) made 20.2 billion yuan ($3.1 billion) in profit last year, with earnings per share standing at 0.45 yuan, according to the company's annual report.

CNOOC Chairman Yang Hua attributed the profit decrease to unabated downward adjustment of the global economy and low international oil prices.

The company's net production rose 14.6 percent from a year earlier to 495.7 million barrels of oil equivalent, but sales dropped 32.8 percent to 146.6 billion yuan.

The average price of oil sold by CNOOC fell 46.6 percent year on year to $51.3 per barrel, while that of natural gas slipped 0.8 percent, the report said.

"The worldwide oil and gas industry is experiencing a 'cold winter'," the report quoted Yang as saying.

Plunges in international oil prices also hit other Chinese oil producers. The net profits of PetroChina, China's top oil and gas producer, shrank more than 60 percent in 2015, a company report showed on Wednesday.