祁连山冻土区天然气水合物中轻烃分析方法及应用

通过自行研发的一套真空密闭加热脱附以及冷柱头零压力进样装置,对采集到的顶空气样进行轻烃在线分析,实现了天然气水合物轻烃C_5-C_7化合物的有效检测。根据Kováts保留指数等前人研究成果,对祁连山木里煤田聚乎更矿区天然气水合物轻烃中C_5-C_7共27个单体化合物进行了定性分析,对该区天然气水合物的轻烃地球化学进行研究。利用甲基环己烷指数对该区天然气水合物成因类型进行划分,揭示木里冻土区天然气水合物气体有2种成因3种类型,其中以混合型为主,并伴有少部分的油型气和煤型气。

Analysis method and geological significance of C5-C7 light hydrocarbons in natural gas hydrate in permafrost,Qilian Mountain

A sample introduction device of vacuum thermal desorption, cold on-column and zero-pressure was built for the identification of C₅-C₇ light hydrocarbons in gas hydrate. On the basis of previous Kováts index research, 27 compounds of C₅-C₇ light hydrocarbons were identified, which provided a foundation for the geochemical study on light hydrocarbons in gas hydrate in the Juhugeng mining area, Muli coal field, Qilian Mountain. Two genetic types of gas hydrate in the Muli permafrost were divided into three types, including oil-type, coal-type and mixed-type gas based on the methylcyclohexane index. The mixed-type gas predominates in the Muli permafrost, while the other two types are in the minority.