Geochemistry and origin of continental natural gas in the western Sichuan basin, China

The molecular compositions and stable carbon and hydrogen isotopes of natural gases of Jurassic and Upper Triassic strata in western Sichuan Basin were investigated to assess the origin, maturity, sources. Then the results were compared with those of central Sichuan Basin. Results show that the natural gas in Western Sichuan basin is wet gas and the dry coefficient is higher than that of central Sichuan basin. The stable carbon and hydrogen isotopes represent a positive carbon isotopic series of alkanes (i.e. delta C-13(1)