By the end of 2015, exploration in these fields will add another 10 billion cu m to annual output, said Cao.

The resources will be used in the 70 cities within six provinces - Sichuan, Hubei, Jiangxi, Anhui, Jiangsu and Zhejiang - and two municipalities, Shanghai and Chongqing.

"China's technology development in sour natural gas exploration can help scale gas output to supplement domestic liquefied natural gas," said Qian.

Also, countries such as Kazakhstan and Uzbekistan in Central Asia are in discussion with Sinopec about introducing its sour gas technology in the development of their industries.

Puguang gas field was discovered in 2003 and developed in 2006 as the key project in China's major energy program to deliver gas from Sichuan to eastern China.

Sinopec invested around 62 billion yuan ($9.96 billion) in the project including gas exploration, pipeline construction and a sour gas purification plant, Cao said.

The purification plant can purify 12 billion cu m of sour natural gas to produce 2.1 million metric tons of sulfur for agricultural use annually, which accounts for 45 percent of China's total sulfur output.

Sulfur is an important element in fertilizer production, so its import and domestic output have a big effect on food prices.

Currently, two-thirds of sulfur consumption in China still depends on imports.

"The purification plant in Puguang has almost doubled China's sulfur output, which helps the country reduce imports and stabilize sulfur prices," said Cao.

The project also can reduce the levels of carbon dioxide by 16.8 million tons each year, and of sulfur dioxide, nitrogen and oxides by 698,000 tons, he said.

Contact the writer at dujuan@chinadaily.com.cn

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