China National Petroleum Corp, the country's largest oil and gas producer, said on Tuesday that it has established two national-level shale gas fields with 23 wells.

One of the fields is located in Changning-Weiyuan, Sichuan province, and the other is in Zhaotong, Yunnan province. The company said it owns the intellectual property rights of four sets of exploration technologies.

By March 10, the company had finished setting up 16 wells in the Changning-Weiyuan field. The daily output in that field of a single straight well is between 2,000 cubic meters to 33,000 cu m and that of a horizontal well is between 10,000 cu m to 160,000 cu m, according to the company.

The company has seven wells in the Zhaotong field, with the daily output of the straight wells at 2,500 cu m and of horizontal wells between 15,000 cu m and 36,000 cu m.

"These wells have good potential for future exploration," CNPC said.

According to China's 12th Five-Year-Plan (2011-2015) on the energy industry, the country will achieve the large-scale commercial production of shale gas by the end of 2015.