China's investment in exploration of oil and gas resources is expected to stand at 80 billion yuan (13.07 billion U.S. dollars) in 2013, according to the Ministry of Land and Resources.

Such investment has risen steadily in China over the past years as the country moves to reduce dependence on imports and ensure security of energy supply.

The ministry figures show that money spent on exploration of oil and gas fields rose from 19.0 billion yuan in 2002 to 67.3 billion yuan in 2011.

In the 2008-2011 period, some 5.01 billion tonnes of petroleum reserves and 2.6 trillion cubic meters of natural gas were discovered.

China's dependence rates on imports of oil and natural gas came in at 58 percent and nearly 30 percent respectively in 2012, according to a report by the Economics and Technology Research Institute of China National Petroleum Corporation.