China's new oil discoveries have added about 12 billion tons of crude oil to the country's reserves since 2008, the Ministry of Land and Resources estimated on Wednesday.

The latest assessment shows that the country's oil reserves reached more than 88 billion tons, up 15 percent from 2003, including about 23 billion tons of mineable reserves.

The new oil discoveries were mainly in six basins including the offshore Bohai Bay, the Ordos Basin in the Inner Mongolia autonomous region, Sichuan, and the Beibu Gulf region.

China's oil discoveries have been increasing steadily in recent years with the investment in oil and gas exploration increasing from 19 billion yuan ($3 billion) in 2002 to 67 billion yuan in 2011.

According to the BP Statistics Review of World Energy 2012, China consumed around 10 million barrels of oil on average daily in 2011, making it the second-largest oil consumer behind the United States.

China also saw a 49 percent increase in its natural gas reserves compared with 2003, reaching 52 trillion cubic meters, including 32 trillion cu m of mineable resources.