天然气水合物客体分子与同位素组成特征及其地球化学应用

GUEST MOLECULAR AND ISOTOPIC COMPOSITIONS OF NATURAL GAS HYDRATES AND ITS GEOCHEMICAL APPLICATIONS

  • 摘要: 对1999-2011年间发表的全球18个地区(包括海洋、内陆海与湖泊、陆域冻土区)244件天然气水合物样品的气体分子与同位素组成数据进行了归纳与总结,结果发现:C1是自然界中天然气水合物的最主要组成成分,C2-C6烷烃和CO2也是其常见的客体分子,C6+、H2S等较少存在于水合物分解气中。海洋、内陆海与湖泊、陆域冻土区天然气水合物的客体分子种类存在一定的差异,且碳氢同位素的组成范围也比较宽泛。根据气体分子与同位素组成数据可有效判识天然气水合物的气体来源与成因类型,甚至在研究水合物形成与分解控制因素、气体迁移与成藏过程等方面也具有重要的指示作用。

     

    Abstract: A global dataset of molecular and stable isotope compositions of hydrate-bound gases from 244 samples in 18 representative regions(including seas, inland seas and lakes, permafrost)is presented and discussed, during 1999-2011. The results indicate that Methane (C1) is the most abundant hydrate-bound gas, while CO2 and C2 -C6 hydrocarbon gases are frequently present in small amounts. Other gases, such as C6+ and H2S, are uncommon. The kinds of guest molecules in gas hydrates from seas, inland seas, lakes and permafrost were different, and the stable isotope composition (δ13C and δD) of hydrate-bound gases varies significantly. In addition to the diagnosis of origins and sources of hydrate-bound gases, molecular and isotopic data can help to better study the control factors of formation and decomposition, and provide valuable insights into the gas migration and accumulation process of gas hydrate.

     

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