煤岩及其主显微组份热解气碳同位素组成的演化

模拟实验是有机地球化学研究的重要组成部分 ,也是油气地球化学研究的重要手段。本文通过煤岩及其主要显微组分的热解成气模拟实验产物的组分和同位素组成分析 ,补充和完善了前人对煤岩热解气同位素组成分布的一些认识。同时 ,对比研究了煤型气与煤岩热解气的碳同位素分馏特征 ,结果表明两者具有良好的一致性 ,认为可以通过精细的热解模拟来提供不同含煤沉积盆地煤型气的判识指标 ,而模拟气与天然气碳同位素组成的对比 ,关键是对同位素分析资料的处理。在模拟系列产物碳同位素分析基础上 ,获得了单一成因来源天然气甲烷、乙烷碳同位素组成与演化程度之间的关系式以及演化过程中甲烷碳同位素之间的关系式 ,这些结果会对混源气的判识有重要意义。

Evolution of Carbon Isotopic Composition in Pyrolytic Gases Generated from Coal and Its Main Macerals

Simulation experiment is an important part in the study on organic geochemistry. It is also an important means for the research of oil and gas geochemistry. According to the analysis of component and isotope composition of pyrolytic gases generated from simulation of coal and its main macerals, we replenish and perfect the predecessor's cognition of isotopic composition in pyrolytic gases generated from simulation in this paper. Moreover, we contrastively study the fractional characteristics of carbon isotope in coal-type gases and pyrolytic gases, and the result shows that they have favourable consistency. Basing on careful simulation, we can gain the decisive index of coal-type gases generated from different coal-bearing sedimentary basin. To the contrast of carbon isotopic composition between natural gases and simulation gases, what the most important is how to deal with the isotopic analysis data. According to the carbon isotope analysis of the simulation series products, we obtain the relationship between methane, ethane carbon isotopic composition and evolution stage in natural gas with single source, and the relationship between methane carbon isotope and ethane carbon isotope in evolution process. All of these results have an important significance to judgie gases of mixed sources.