粗糙石英纳米孔隙甲烷流动分子模拟  

Molecular simulation of methane flow in rough quartz nanopores

作　　者：吕方涛 宁正福[1,2] 穆中奇 贾泽江 刘蓓[3] LYU Fangtao;NING Zhengfu;MU Zhongqi;JIA Zejiang;LIU Bei(National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China;National Key Laboratory of Heavy Oil Processing,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [2]中国石油大学(北京)石油工程学院,北京102249 [3]中国石油大学(北京)重质油全国重点实验室,北京102249

出　　处：《东北石油大学学报》2023年第5期82-91,I0006,共11页Journal of Northeast Petroleum University

基　　金：国家自然科学基金联合基金项目(U19B6003-03-04);国家自然科学基金项目(51774298)。

摘　　要：为研究纳米孔隙中的气体流动特征,采用蒙特卡洛和分子动力学模拟方法研究石英纳米孔隙中的甲烷赋存与流动特征,分析纳米孔隙大小、孔隙压力、孔隙压力梯度及孔隙表面粗糙度对气体吸附和流动的影响。结果表明:可以用修正滑脱的泊肃叶方程描述石英纳米孔隙中的甲烷流动;纳米孔隙中的尺寸效应使气体的物性变化偏离体相特征;较高压力下,孔隙中的吸附气和自由气密度较高,气体分子间相互作用强,不利于气体的流动;粗糙孔壁吸附位点减少降低吸附性能,孔隙表面粗糙单元降低甲烷流动的有效孔径,与甲烷的相互作用增强,流动阻力增大,阻碍气体的流动。该结果对页岩气产能评价及提高气体采收率具有指导意义。In order to study the gas flow characteristics in nanopores,Monte Carlo(MC)and molecular dynamics(MD)simulations were utilized to investigate the occurrence and flow characteristics of methane in quartz nanopores,and analyzed the effects of pore size,pressure,driving force and pore surface roughness on gas adsorption and flow.The results show that methane flow in quartz nanoconfined space can be well described by the slip-corrected Poiseuille equation.The size effect in the nanopores is significant,which leads to the deviation of the gas physical properties from its bulk phase characteristics.The density of adsorbed and free gas in the pores is higher at higher pressure,and the interaction between gas molecules is stronger and thus less conducive to gas flow.The reduction of adsorption sites on the rough pore surface weakens its adsorption capacity,and the presence of rough elements on the pore surface reduces the effective pore space for methane flow and enhances its interaction with methane molecules,leading to increased resistance to flow and thus impeding gas flow.The results are of great significance for the evaluation of shale gas production capacity and enhanced gas recovery.

关 键 词：页岩气 表面粗糙度 蒙特卡洛模拟 分子动力学模拟 气体采收率 粗糙石英 纳米孔隙 甲烷 

分 类 号：TE312[石油与天然气工程—油气田开发工程]