页岩气在有机质中吸附规律的分子模拟研究

发布时间：2018-05-18 23:37

本文选题：CH_ + 干酪根　；参考：《中国科学:物理学力学天文学》2017年11期

【摘要】：甲烷(CH_4)在页岩有机质中的吸附行为对页岩气的开采有重要的意义,选取有机质作为研究对象,构建I型干酪根模型,采用巨正则系综蒙特卡罗(Grand Canonical Ensemble Monte Carlo,GCMC)方法和分子动力学(Molecular Dynamics,MD)方法研究不同温度、不同压力下CH_4气体在Ⅰ型干酪根中的吸附行为.结果表明:(1)CH4气体吸附时吸附量随着压力的增大会增大,CH_4气体吸附符合朗缪尔(Langmuir)吸附规律,可以使用Langmuir方程进行拟合;(2)温度对CH_4的吸附有着较大的影响,高温不利于CH_4气体在干酪根中的吸附,相同的平衡压力下,温度越高,吸附量越小;(3)径向分布函数表明干酪根中不同的原子对CH_4气体的吸附起着不同的作用;(4)在低压阶段,吸附是引起体积应变的主要原因,在高压阶段,压力则对体积应变发挥明显作用.
[Abstract]:The adsorption behavior of CH4) in shale organic matter is of great significance for shale gas extraction. The model of type I kerogen is constructed by selecting organic matter as the research object. The adsorption behavior of CH_4 gas in type I kerogen at different temperatures and pressures was studied by means of the grand canonical ensemble Monte Carlo (GCM) method and molecular dynamics (MD) method. The results show that the adsorption capacity of Ch _ 4 gas increases with the increase of pressure. The adsorption of Ch _ 4 gas accords with Langmuir (Langmuir) adsorption law. The Langmuir equation can be used to fit the adsorption of Ch _ 4. The temperature has a great influence on the adsorption of CH_4. The high temperature is not conducive to the adsorption of CH_4 gas in kerogen. At the same equilibrium pressure, the higher the temperature, the smaller the adsorption amount is.) the radial distribution function shows that different atoms in kerogen play different roles in the adsorption of CH_4 gas at low pressure. Adsorption is the main cause of volume strain. At high pressure, pressure plays an important role in volume strain.
【作者单位】：中国石油大学理学院;中国石油大学石油工程学院;
【基金】：国家自然科学基金(编号:51574268,51234007,51490654,51504276) 山东省自然科学基金(编号:ZR2014EM050)资助
【分类号】：P618.13;TE31

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