祁连山冻土区天然气水合物烃类气体成因及其意义

对祁连山冻土区天然气水合物钻井岩心游离气样品开展研究，测试烃类气体的组分和碳氢同位素，判断天然气水合物的气体成因类型及成藏模式。结果显示烃类气体组分复杂，除甲烷外，还含有较高的乙烷、丙烷等重烃组分。甲烷碳同位素分布范围最广，气体成因来源相对简单，没有明显受到次生改造作用的影响。该区天然气水合物属于热解成因，判断来自深部的三叠统尕勒得寺组烃源岩。本研究可为我国高原冻土天然气水合物勘探和开发提供理论依据。

Gnetic—type and its significance of hydrocarbon gases from permafrost—associated gas hydrate in Qilian Mountain

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.