That raises the total estimated geological reserve of the Fuling block in southwestern China, the country's first large commercial shale gas project, to 792.64 bcm, according to a statement from the company known as Sinopec.

The newly proven reserves at Fuling were certified by the Ministry of Natural Resources, the company said.

Sinopec President Ma Yongsheng said earlier this year that the company aims to nearly double its shale gas output to 13 bcm per year by 2025, in response to Beijing's call to improve the country's energy security and to boost natural gas consumption.

Sinopec has total proven geological shale gas reserves of 940.77 bcm in China, the statement said.

(Reporting by Muyu Xu in Beijing and Chen Aizhu in Singapore; Editing by Christian Schmollinger)