Research on headspace gas taken from gas hydrate drilling wells is carried out in this paper. The characteristics of hydrocarbon gas composition and isotopic characteristics were analyzed by testing its hydrocarbon gas content and carbon and hydrogen isotope of methane，and genetic—types of hydrocarbon gases were discussed. Analytic results show that gas composition of gas hydrates in this area is complex， containing main methane and high ethane， propane and other heavy hydrocarbon. Methane carbon isotope is most widely distributed. Gas hydrates belong to geothermal type， with simple gas origin and without significant impact of secondary alteration. Through the preliminary judgement， the hydrocarbon gases come possibly from source rocks in the Galadeshi Formation of Upper Triassic. The results will provides the theory basis for exploration and development of permafrost—associated gas hydrate in China.
Huang Xia,Liu Hui,Zhang Jiazheng et al. Gnetic—type and its significance of hydrocarbon gases from permafrost—associated gas hydrate in Qilian Mountain[J]. Chinese Journal of Geology, 2016, 51(3): 934-945.