"Good oil resources in other areas of the world have already been carved up by international oil giants, and there are not many choices left for Chinese companies," said Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University.

To satisfy the country's energy demand, companies are looking both overseas and domestically.

China's oil output in the past year reached 207.5 million metric tons, up 1.9 percent year-on-year, according to figures from the China Federation of Logistics and Purchasing.

The country's oil output in December reached a record high of 17.94 million tons - an increase of 5.6 percent year-on-year as the nation's economic growth started to rebound after slowing for seven quarters.

China's GDP growth rose from 7.4 percent in the third quarter to 7.9 percent in the fourth quarter last year.

The Changqing oilfield in western China, owned by CNPC, will replace the Daqing oilfield to become the largest oilfield in the country with an annual output of 50 million tons by 2015, according to figures from the company's website.

In the past year, the Changqing oilfield had a total output of 45 million tons.

dujuan@chinadaily.com.cn