China, the world's top energy user, added more oil and gas reserves last year versus 2010, an official of the Ministry of Land and Resources said on Thursday.

New geologically proven oil reserves were 1.34 billion tonnes (9.78 billion barrels) in 2011, up 18 percent from the previous year, while new proven natural gas reserves surged 22 percent to 722.5 billion cubic metres, a ministry official quoted 2012 China Mining Resources Report as saying.

The report will be released in the next few days.

Remaining oil reserves that are technically recoverable stood at 3.24 billion tonnes (23.65 billion barrels) at the end of 2011, up 2.1 percent from the previous year, said the official who declined to be named because he is not authorised to talk to the media.

Remaining natural gas reserves that are technically recoverable were 4.02 trillion cubic metres at the end of last year, up 6.4 percent from 2010, the official added.

Potential assessments by the ministry showed China's onshore geological shale gas resources were 134 trillion cubic metres, while recoverable shale gas resources were 25 trillion cubic metres, he added, in line with the ministry's earlier estimate announced in March.

Of the other mining resources, proven coal resources were 1.38 trillion tonnes at the end of last year, iron ore resources were 74.39 billion tonnes, copper ore 86.12 million tonnes, bauxite 3.87 billion tonnes, and gold 7,419 tonnes, according to a report on the ministry website (www.mlr.gov.cn) on Thursday.

Total investment in exploring mining resources rose 9.2 percent to 111.82 billion yuan ($17.9 billion) in 2011. Of which, investment in oil and gas exploration rose 9.4 percent to 67.47 billion yuan, it added.