Significances of studies on natural gas geology and geochemistry for natural gas industry in China

In the recent decade, great development has been made in the natural gas industry. By the end of 2007, the total proved geological reserves of natural gas were 6 × 1012 m3. At the same time, the increase rate of annual production has been greater and greater. From the 100 × 108 m3/year in 1976 to 500 × 108 m3/year in 2005, the required time for an increase of 100 × 108 m3 has been 20 years, 5 years, 3 years, and 1 year, respectively. The significance of studies on natural gas geology and geochemistry are: in the 1970s, it was proposed that coal measure be good gas source rocks, and that the coal measure hydrocarbon generation be dominated by gas generation with some oil generation, which opened new opportunity for coal gas exploration and made coal gas increase from 9% to 70% of the total natural gas in China; according to studies on the semi-quantitative and quantitative controlling factors on large gas fields formation and natural gas accumulation zones, 7 out of 11 large gas fields of more than 1 000 × 108 m3 were predicted in advance by 4–11 years; the gas sources of Feixianguan Formation accumulations are various, and the authors expect that there is a coal gas generation center from Longtan Formation in Bazhong, north Sichuan, which is favorable for large coal gas fields.