A total of 3.8 trillion cubic metres (133 trillion cubic feet) of natural gas deposits have been found in the western part of the Sichuan Basin, the China Daily said, citing officials in Dazhou city, near the reserve.
The discovery is equivalent to about 60 years of China's total production at current output levels.
The deposits include proven exploitable reserves of a newly-discovered 244 billion cubic metres of gas alongside the 356 billion cubic metres in Puguang gas field, which was announced in March, the report said.
It has become the largest gas field in the country, topping the Sulige gas field in north China's Inner Mongolia Region discovered last year with exploitable reserves of 533.6 billion cubic metres, the newspaper said.
China plans to boost its annual natural gas output from 49.3 billion cubic metres in 2005 to 92 billion cubic metres by 2010, as consumption is expected to more than double the 2005 figure to top 100 billion cubic metres by 2010.
The government has strengthened exploration efforts in a bid to feed the country's brisk economic expansion that has seen double-digit growth for four consecutive years.
Last week, a large gas field with reserves of nearly 30 billion cubic metres was discovered in Karamay in the Xinjiang region in the northwest.
A major oil field, the Jidong Nanpu oil field in Bohai Bay in the north, has also been announced recently.
The oil field is the largest discovery in the country in more than four decades, with expected reserves reaching one billion tonnes or about 7.35 billion barrels.
