China National Offshore Oil Corp. said Friday a "harsh" climate for global oil prices in part led to a 39.9 percent decline in revenue for the first quarter.

The company, China's top offshore oil producer, said oil and gas sales revenue for the first quarter of the year dropped off substantially in part because of slumping global crude oil prices during the period.

The price for Brent, the global crude oil benchmark, dipped below the $50 per barrel mark in early January, a value that was less than half its June 2014 high. Peer companies, from BP to oil services company Schlumberger, have cut spending or staff numbers in order to cope with the weak crude oil market.

CNOOC said it was trimming its capital spending plan by 15.7 percent compared with last year to $2.6 billion as a result of lower oil prices. It added its own realized oil price decreased 49 percent year-on-year to $53.30 per barrel.

Revenue dropped to $5.73 billion in the first quarter.

The company said it was bolstered by efficiency, however, stating that total net production during the first quarter increased 9.4 percent over the same period last year to 118.3 million barrels of oil equivalent, mostly from new projects offshore China.

"Under the harsh circumstances, the company's overall production and operations remained stable in the first quarter," Chief Executive Officer Li Fanrong said in a statement. "Our cost control and enhanced efficiency measures were executed effectively and achieved good results."