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为揭示热演化过程中地质因素演变对页岩甲烷吸附能力的影响,选择鄂尔多斯盆地东南部延长组长7段张家滩页岩为研究对象,经过热模拟实验获得7个不同模拟埋深的模拟样品,对各样品的有机地球化学参数、矿物组成、孔隙结构以及甲烷吸附量进行测试分析。研究发现,热演化过程中影响页岩甲烷吸附能力的地质因素可以分为比表面积和孔隙等物性因素、TOC值和成熟度等有机地球化学因素以及黏土矿物和伊/蒙混层含量等矿物成分因素等3类。地质因素对于页岩吸附能力的影响是复杂的,综合考虑各因素会增加其与吸附量的相关性。微孔是影响页岩甲烷吸附能力的最重要的因素,两者呈正相关。由于有机质热演化产生的微孔增加了吸附空间,所以吸附量随TOC值的降低而增加。此外,页岩埋深与其吸附能力负相关,且埋藏越深吸附能力下降越快。
In order to reveal the influence of geologic factors on the methane adsorption capacity of shale in the process of thermal evolution, Zhangjiatan shale in Chang 7 Member of Yanchang Formation in the southeast Ordos Basin was selected as the research object. Seven simulations with different simulated burial depths were obtained by thermal simulation Samples, the organic geochemical parameters of each sample, mineral composition, pore structure and methane adsorption capacity of the test analysis. It is found that the geological factors affecting the methane adsorption capacity of shale during thermal evolution can be divided into physical factors such as specific surface area and porosity, organic geochemical factors such as TOC value and maturity, and mineral composition factors such as clay mineral and Iraq / And other three categories. The influence of geological factors on the adsorption capacity of shale is complex. Considering all the factors, it will increase the correlation with the adsorption capacity. Microporosity is the most important factor affecting the methane adsorption capacity of shale, and the two are positively correlated. As micropores produced by thermal evolution of organic matter increase the adsorption space, the adsorption capacity increases with decreasing TOC. In addition, the burial depth of shale is negatively correlated with its adsorption capacity, and the deeper the burial, the faster the adsorption capacity declines.