甲烷在页岩黏土矿物孔中的赋存力学机制

发布时间：2018-08-14 17:06

【摘要】：利用低压氮气吸附法,研究了不同类型黏土矿物孔隙结构特征,在此基础上,利用分子势能理论研究甲烷分子在黏土矿物孔隙中赋存力学机制,揭示了页岩中黏土矿物吸附甲烷的本质。文中从分子间作用力角度出发,利用势能理论建立了单一甲烷分子在孔中相互作用的势能计算模型,即孔径与甲烷分子在孔内位置的双重函数。研究结果表明:甲烷分子越靠近孔壁,势能越大;远离孔壁,势能迅速减小。受到孔壁面势能作用影响的甲烷分子,呈吸附态;未受到影响的,呈游离态。随着孔径增大,甲烷分子受壁面影响区域比例减小,甲烷吸附能力降低。当孔径大于20 nm时,甲烷分子受壁面势能影响区域较小。从微观角度讲,相同孔径中,甲烷分子与黏土矿物间的相互作用力大小顺序依次为高岭石、蒙脱石(伊利石)、绿泥石;从宏观角度讲,黏土矿物样品对甲烷分子的作用力大小的顺序依次为蒙脱石、高岭石、绿泥石、伊利石。
[Abstract]:The pore structure characteristics of different clay minerals were studied by low pressure nitrogen adsorption method. On this basis, the mechanism of methane molecule occurrence in clay mineral pores was studied by molecular potential energy theory, and the nature of methane adsorption by clay minerals in shale was revealed. The results show that the closer the methane molecule is to the pore wall, the greater the potential energy is; the farther away from the pore wall, the faster the potential energy decreases. When the pore size is larger than 20 nm, the influence area of wall potential energy on methane molecule is smaller. From microscopic point of view, the order of interaction force between methane molecule and clay mineral is kaolinite and montmorillonite (illite) in the same pore size. From the macroscopic point of view, the order of action of clay mineral samples on methane molecules is montmorillonite, kaolinite, chlorite and illite.
【作者单位】：西南石油大学油气藏地质及开发工程国家重点实验室;
【基金】：国家自然科学基金青年科学基金项目“页岩纳米级孔隙中甲烷解吸的微观机理研究”(41602155)
【分类号】：P618.13

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