Workers change the billboard at a Sinopec gas station in Fuzhou, Fujian province. [Photo provided to China Daily]

China Petroleum and Chemical Corp, known as Sinopec, the world's largest refiner by volume, said on Tuesday its Yuanba gas field has produced more than 22 billion cubic meters of natural gas since it was put into operation in 2014, which has helped ensure national energy security, improve the ecological environment and promote local economic construction.

As the world's first large gas field with buried depth of more than 7,000 meters and a high-sulfur content reef, the gas field is ultra-deep, high temperature, high pressure and boasts a high hydrogen sulfide content. It will benefit more than 200 million households in 70 cities, according to Sinopec's Southwest Petroleum Bureau, a subsidiary of the group.

Located in Guangyuan, Nanchong and Bazhong of Sichuan province, the Yuanba gas field is an important source for the "Sichuan Gas East" transmission project and has helped the Sichuan-Chongqing region build a national gas production base of 100 billion cubic meters. 

The gas field started construction on Aug 29, 2011 and was put into production in December 2014.