Yuanba gas field, Sinopec's second largest high-sulfur natural gas reservoir, will go into full production by the end of this year. Annual output capacity is planned to reach 3.4 billion cubic meters.

The gas field, located in southwestern China's Sichuan province, is the deepest found in China. The depth of the gas reservoir is 6,800 meters in average, according to Sinopec's Southwest Oil & Gas Company, the developer.

The gas field contains 230 billion cubic meters of proven reserves. It is the second largest high-sulfur natural gas field in China after the Puguang gas field, which is no more than 200 kilometers away, and has proven reserves of 412.2 billion cubic meters.

The construction of the Yuanba gas field started in August 2011. The first phase was completed by the end of 2014, with an annual output capacity of 1.7 billion cubic meters. The second phase, which is scheduled to be completed by the end of this year, aims to increase capacity to 3.4 billion cubic meter a year.

"Yuanba is another major gas source for China's Sichuan-East Gas Transmission Project, after the Puguang gas field. It is of vital importance to ensure China's energy security and optimize the country's energy structure," Zhang Bailing, deputy director of Sinopec's Southwest Oil & Gas Company, said.