The state-run company said the field will tap a proven reserve equivalent to 124.7 bcm of gas at Weirong in the southwestern province of Sichuan. This marks its second major shale gas discovery after a flagship development at Fuling in the Chongqing region, situated in the same geological basin of Sichuan.

The company is drilling for shale gas in a 20,000 square-kilometre area in southern Sichuan, as well as western Chongqing. It earlier set a target to produce 10 bcm per year of shale gas by 2020.

China's shale gas output accounts for only a small part of the country's total gas production, at about 6 percent.

Separately, Sinopec reported high volumes of gas flows in an exploration well Dongye-1 in the Dingshan-Dongxi block, close to Chongqing. The well, which extends some 4,200 metres below surface level, yielded daily output of 310,000 cubic metres in test production, said Sinopec.

(Reporting by Chen Aizhu; Editing by Kenneth Maxwell)