As of Monday, Daqing Oilfield Co, a subsidiary of China National Petroleum Corp in Heilongjiang province, achieved the cumulative natural gas production of 4.01 billion cubic meters in its exploration area of Sichuan province and Chongqing, the company said on Tuesday.

It's a major achievement in the development and construction of the Sichuan-Chongqing exploration area, which spans Chongqing and the cities of Guang'an, Nanchong, Dazhou, and Bazhong in Sichuan, covering an area of 16,300 square kilometers with geological reserves of over 100 billion cubic meters.