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Geoscience ›› 2010, Vol. 24 ›› Issue (3): 581-588.

• Water Resource and Environment • Previous Articles     Next Articles

Study on Genesis of Gases from Gas Hydrate in the Qilian MountainPermafrost, Qinghai

 LU Zhen-Quan1, ZHU  YOU-Hai1, ZHANG  Yong-Qin2, WEN  Huai-Jun3   

  1. 1.Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing100037, China;
    2.Institute of Exploration Techniques, Chinese Academy of Geological Sciences, Langfang, Hebei065000, China;
    3.Qinghai No105 Coal Geological Exploration Team, Xining, Qinghai810007, China
  • Online:2010-06-21 Published:2010-08-17

Abstract:

The genesis or origin of gases from gas hydrate becomes an important scientific issue after gas hydrate is discovered in the Qilian mountain permafrost, Qinghai. The composition and isotope of gases from gas hydrate and the relevant diagrams of δ13C1-1/n、 C1/(C2+C3)-δ13C1、δDCH413CCH4、( δ 13C213C3)-ln(C2/C3)、ln(C2/C3)-ln(C1/C2) are studied in this paper. Conclusions are drawn out: In the Qilian mountain permafrost, Qinghai, gases from gas hydrate are mainly composed of light hydrocarbons with features of wet gas; The isotopes are characteristic of normal carbon isotopic series. In the study area, gases from gas hydrate are organic and preferably of thermal genesis with secondarily of microbial genesis (acetate fermentation); Gases of thermal genesis are predominantly from crude oil cracking or in association with crude oil generation, and minor or trace of them are associated with condensate gases, coaltyped gases, kerogen cracking gases. This analytical result probably implies that gas source of gas hydrate is closely related to oiltyped gases rather than coaltyped gases in the study area.

Key words: gas hydrate, genesis, permafrost, Qilian mountain, Qinghai

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