煤系有机质多阶段成气的分子碳同位素表征及其对高过成熟干酪根生气潜力评价的启示  

Multiple stages of gas generation from coal organic matter as revealed by molecular isotopic geochemistry and implications for gas generation potential assessment of highly to over mature kerogen

作　　者：孙永革[1,2] 杨中威[1,4] Bernhard CRAMER 

机构地区：[1]中国科学院广州地球化学研究所有机地球化学国家重点实验室,广东广州510640 [2]浙江大学地球科学系,浙江杭州310027 [3]Federal Institute for Geosciences and Natural Resources (BGR),Hannover 30655,Germany [4]中国科学院大学,北京100049

出　　处：《地球化学》2013年第2期97-102,共6页Geochimica

基　　金：国家自然科学基金(40972093);提高石油采收率国家重点实验室基金和油气资源与探测国家重点实验室基金(2009001)

摘　　要：采用开放体系在线程序升温裂解-色谱-碳同位素比值质谱技术(PY/GC-IRMS)考察了煤系有机质热演化过程中甲烷瞬时生成速率与碳同位素组成特征,提出煤系有机质不同热演化进程甲烷生成的四个阶段:生油窗阶段、主生气阶段、晚期生气阶段(芳环侧链断裂)、开环-缩聚作用阶段。以一级反应动力学为基础,采用高斯分布算法,计算了各阶段甲烷产出的动力学参数。研究结果对煤成气资源量的正确评价,特别是近年来有机质高演化阶段成气潜力的评价具有重要指示意义。This paper investigated instantaneous generation rate of methane and its stable carbon isotope composition during the course of thermal simulation by using open system, on-line pyrolysis gas chromatography mass spectrometer, to identify the reaction types for methane generation during thermal evolution. It revealed that hydrocarbon generation from coal organic matter could be characterized by 4 stages, i.e. oil window, main gas generation, late gas generation and cyclic cleavage-condensation. Using first-order reaction modeling and Gaussian distribution, kinetic parameters for methane generation were calculated and quantitatively evaluated. The results will have important implications for the evaluation of coal organic matter-derived gas reserve, especially for the gas generation potential assessment of highly to over mature source rocks.

关 键 词：煤系有机质 多阶段成烃 碳同位素 甲烷 裂解气相色谱-同位素比值质谱 

分 类 号：P593[天文地球—地球化学]