China Oilfield Services Limited (COSL) said on Sunday its profits were up 98 percent last year on rising business revenue.

Net profits reached 2.24 billion yuan (US$315 million), with earnings per share of of 0.54 yuan, the listed subsidiary of the country's largest offshore oil producer, China National Offshore Oil Corp said on the Shanghai Stock Exchange.

Business revenue rose 42 percent to 9.24 billion yuan last year, with revenue hitting record high in four of its main businesses, including drilling, marine and transportation, oilfield technology and geophysical survey, said the company.

Meanwhile, revenue in overseas services stood at 1.6 billion yuan, up 49 percent.

COSL announced this month that it had signed a service contract worth almost 400 million yuan (US$56 million) for deep water operation.

According to the contract, COSL will provide technician services for a foreign company engaging in deep water operations in the eastern part of the South China Sea.