PetroChina Co, the country's biggest oil and natural gas producer, is on course to surpass its target of 2.6 billion cubic meters of shale gas production in 2015 from fields in Sichuan province.

"Based on the production of our test wells, we are very confident to achieve or even beat our estimates for 2015," Xie Jun, deputy general manager of unit Southwest Oil Gasfield Co, said last week in Chengdu. The estimate is "very conservative" and newer technology may push the number much higher, he said.

PetroChina's success in drilling for shale gas is good news for China, which is seeking to replicate the boom in the United States. China's hopes have rested on China Petroleum Chemical Corp (Sinopec), which operates the nation's largest shale project in Fuling.