摘要:
有机地球化学研究中,目前大量的报导是对地质样品中可溶有机质的组成、结构的研究。可溶有机质中正烷烃偶奇优势,甾、萜分布等,已广泛用于油、气勘探,评价生油岩有机质母质来源、成熟度和对比油源。但可溶有机质碳含量占生油岩中有机碳不到百分之五,生油岩中大部分有机质是以干酪根形式存在,油、气的成因与干酪根密切相关。近年来,裂解色谱、裂解色谱-质谱已用于研究干酪根中结合烃类的组成、结构,并用于指示沉积岩中有机质的成熟度、母质输入等[1、2、2],我国近年来也开始研究干酪根的裂解色谱1)，本文则报导利用裂解色谱、裂解色谱一质谱研究一个已知地球化学剖面沉积有机质成熟度和沉积环境的尝试，探索建立评价生油岩成熟度的快速、有效的有机地球化学方法。
Abstract:
The source rocks from the first,third and fourth sections of Shahejie formation of Zhanhua depression have been analyzed by PY-GC and PY-GC-MS in this study and a detective method of multiple ions is employed to determine the triterpanes and triterpenes in the source rocks. The pyro-chromatograms of the source rocks of Zhanhua depression show that the distribution of n-alkane/n-alkene doublets is broad and that the first section and third section of the Shahejie formation have a n-alkane/n-alkene doublet distribution with odd over even preference and higher Pr/Ph ratio. On the contrary,the pyro-chromatogram of the forth section has n-alkane/n-alkene doublet distribution with an even over odd prefeence and lower Pr/Ph ratio. Thus, the fourth section of Shahejie formation is suggested as a saline lake sedimentation with reducing environment and that these indexes, such as n-alkane/n-alkene doublets distribution and Pr/Ph ratio, etc., can be used as the criteria of a sedimentary envirnment. The PY-GC, PY-GC-MS chromatograms of the source rocks of Zhanhua depression show that the insoluble organic matters, such as prist-l-ene/n-C17, C30 Ho-pane, 17β(H(21α(H)/17α(H)21β(H), C27Hopane 17β(H)/17a(H) C27Hopene/C27 17α(H)Hopane, etc. decrease with increasing maturity of the samples, and that C31 Hopane, 17α(H)21β(H)22S/17α(H)21β(H) 22(R+S)% increase with increasing maturity of the samples/ As a result, they demonstrate that these parameters can be employed to measure the maturity of organic matters in sediment. However, the result of the present study has shown that PY-GC and PY-GC-MS are useful means to evaluate the deposition environment of source rocks and its maturity.
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