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结合黄金管热模拟实验及模拟产物的轻烃(C_(6-14))定量分析,对不同类型有机质热演化过程中轻烃产率及组成特征进行了对比研究。基于热解—色谱—质谱(PY-GC-MS)方法对模拟产物轻烃定量分析表明,具有较高氢指数(I_H)的湖相Ⅰ型和海相Ⅱ_1型有机质的轻烃产率明显高于海相Ⅱ_2型有机质。松辽盆地白垩系湖相Ⅰ型有机质的最大轻烃产率为33.56mg/g_(TOC),张家口地区下马岭组海相Ⅱ_1型有机质的最大轻烃产率为39.58mg/g_(TOC),四川盆地二叠系海相Ⅱ_2型有机质的最大轻烃产率为10.08mg/g_(TOC)。相对来说,轻烃产物中芳烃相对含量明显要高于饱和烃。同时,Ⅰ型有机质达到最大轻烃产率对应的热解温度或成熟度要明显低于Ⅱ_型有机质。热解过程中不同碳数正构烷烃产率的演化结果表明,低碳数烷烃达到最大产率时的等效镜质体反射率(Easy%R_O)值普遍高于高碳数烷烃,这归因于低碳数烷烃生成和裂解时的活化能更高。此外,通过热解过程中轻烃产物组成分析,认为萘含量、苯/正己烷与甲苯/正庚烷等参数与成熟度具有明显的相关性,可用于指示有机质热演化程度。
Combined with the thermal simulation experiment of gold tube and the quantitative analysis of the light hydrocarbons (C 6-14), the yield and composition of light hydrocarbons during the thermal evolution of different types of organic matter were compared. Quantitative analysis of the light hydrocarbons based on pyrolysis-chromatography-mass spectrometry (PY-GC-MS) showed that the yield of light hydrocarbons of lacustrine type Ⅰ and Ⅱ_1 marine organic matter with high hydrogen index (I_H) In the sea phase Ⅱ 2 organic matter. The maximum light hydrocarbon yield of Cretaceous lacustrine facies-Ⅰ organic matter in Songliao Basin was 33.56mg / g TOC. The maximum light hydrocarbon yield of marine-derived Ⅱ_1 organic matter in Xiamaling Formation in Zhangjiakou area was 39.58mg / g_ (TOC) The maximum light hydrocarbon yield of Permian marine Ⅱ 2 organic matter in the Sichuan Basin was 10.08 mg / g_ (TOC). Relatively speaking, the relative content of aromatic hydrocarbons in light hydrocarbon products is obviously higher than saturated hydrocarbons. At the same time, the pyrolysis temperature or maturity corresponding to the maximum light hydrocarbon yield of Type I organic matter was significantly lower than that of Type II organic matter. The evolution of different n-alkanes yield during pyrolysis showed that the values of Easy% R_O were generally higher than those of high-carbon alkanes at low carbon alkanes, The activation energy is higher when low alkanes are generated and cleaved. In addition, the composition of light hydrocarbons in the pyrolysis process analysis, that naphthalene content, benzene / n-hexane and toluene / n-heptane and other parameters and maturity has a significant correlation can be used to indicate the degree of thermal evolution of organic matter.