The latest find in Sichuan "will help ease China's natural gas supply shortage in the long run," said Liu Yijun, a professor at the China University of Petroleum.

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Based on the current development plan, the field's output will be able to satisfy one-third of new domestic demand in coming years.

"Meanwhile, China will have an advantage during natural gas import negotiations with other countries, including Russia," he said. "China will be able to wait for the right time [to buy overseas] when we have such a big proven reserve."

The reservoir has proven geological reserves of 440.38 bcm of natural gas, with technically recoverable reserves of 308.2 bcm, as certified by the Ministry of Land and Resources.

Last year, China's new proven geological natural gas reserves reached 616.43 bcm, with the Longwangmiao find accounting for 71.4 percent of the total, according to the ministry.

PetroChina Southwest is working on a project with an annual production capacity of 4 bcm. The company also has started preliminary work on the second phase of the project, which will have a capacity of 6 bcm.

"It is the biggest natural gas capacity building project in the Sichuan Basin, one of China's richest natural gas producing regions," said Li.

"When the project is completed, it will help accelerate the environmental and economic development of the region and reduce air pollution," said Li.

Natural gas accounts for 15 percent of the primary energy mix in the Sichuan Basin area, well above the national level.

China's natural gas consumption accounted for 5.9 percent of the primary energy mix, far behind the levels in developed countries.

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