Workers on Monday completed a tunnel under China's Yangtze River for a major gas pipeline that will run from the southwest province of Sichuan to Shanghai.

With a diameter of 3.08 meters and a length of 1,405 meters, the tunnel lay about 20 meters beneath the riverbed, connecting two wells on each bank in Yichang City, Hubei Province, said Liu Juzheng, head of the Hubei section of the Sichuan-Shanghai pipeline.

The 2,203-km pipeline, with the mainline extending 1,700 km, is another "energy artery" to fuel the booming but energy-insufficient east following the West-East gas project.

The pipeline is expected to channel 12.1 billion cubic meters of natural gas annually from Sichuan's Puguang field to central and eastern regions, including Chongqing Municipality, the provinces of Hubei, Anhui, Jiangxi, Jiangsu and Zhejiang, and Shanghai.

The tunnel, which took 325 days to finish, is the first of five to cross under the Yangtze, which originates in Qinghai Province and empties into the East China Sea near Shanghai.

Industry experts say this new gas pipeline, with an investment of 62.7 billion yuan (8.25 billion U.S. dollars), offers an opportunity to the country's underdeveloped west to tap its advantage in resources for development.

The pipeline is scheduled to be finished by late 2010 and the gas is expected to help reduce carbon dioxide emissions by tens of millions of tons annually, said Chen Deming, Vice Minister of the National Development and Reform Commission (NDRC).

Proven reserves of the Puguang gas field stood at 356.1 billion cubic meters, according to China Petrochemical Corporation (Sinopec).

China's proven reserves of natural gas total 2.66 trillion cubic meters. The government has been promoting the use of natural gas to improve energy efficiency and cut air pollution.

Under an NDRC proposal on natural gas development, China aims to increase its natural gas pipeline network to 44,000 kilometers by 2010 to meet demand.

Although China's natural gas output will reach 94 billion cubic meters in 2010 from 58.6 billion in 2006, the country would still need imports to fill a gap of 16 billion cubic meters a year.

In Shanghai, demand for natural gas has soared from?400 million cubic meters in 2003 to 1.9 billion in 2005.

In 2004, China National Petroleum Corp. opened its West-East gas pipeline, which runs more than 4,000 kilometers and channels 1.2 billion cubic meters of gas to Shanghai from the Tarim Basin in the country's westmost region of Xinjiang annually.

CNPC is to build a second West-East pipeline to carry gas imported from Central Asia to the Pearl River and Yangtze River deltas. Construction will begin in 2008 and gas supply in 2010. The designed annual production volume will be 30 billion cubic meters.

(Xinhua News Agency October 29, 2007)