基于密度泛函理论研究页岩气藏气固吸附微观机理

项目名称： 基于密度泛函理论研究页岩气藏气固吸附微观机理

项目编号： No.51204141

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 冶金与矿业学科

项目作者： 汪周华

作者单位： 西南石油大学

项目金额： 25万元

中文摘要： 我国页岩气勘探开发处于初级阶段，对页岩气吸附微观机理认识存在技术空白。将采自于四川盆地典型页岩气藏储层岩心，利用X射线、红外、比表面及孔隙度测量仪、元素分析仪等表征手段分析岩心抽提物的分子结构参数信息，建立岩心表面片段的分子结构。应用分子动力学和量子力学方法（如密度泛函理论方法DFT等），从分子尺度模拟页岩气体组分（CH4, C2H6，CO2, N2等）与岩心表面的竞争吸附作用；研究CH4气体分子在不同晶面的吸附行为，比较分子在不同吸附位的吸附特性（吸附能），分析不同矿物组成对CH4吸附的影响。开展页岩气在实际页岩气藏储层岩心中吸附规律实验研究和敏感实验，通过不同条件下的页岩岩心对页岩气吸附实验测定和分析，研究岩心矿物组成、有机碳含量、储层温度、压力等对页岩气及其他伴生气体组分的吸附规律,并与模拟结果进行对比分析。项目研究成果对认识页岩气赋存机理具有重要指导意义。

中文关键词： 页岩气；吸附；分子尺度；蒙特卡洛；密度泛函

英文摘要： In our country, the exploration and development of the shale gas reservoirs is at the initial stage, there are technology gaps in understanding the microscopic mechanism of shale gas adsorption.The molecular structures of the shale cores surface are characterized based on the measurement of the frameworks and the elemental compositions of the shale mined from Sichuan Basin with X ray, infrared, specific surface and porosity admeasuring apparatus and elemental analyzer. The competitive adsorption effects of gas mixtures such as CH4, C2H6, CO2 and N2 in the microporous shales are simulated using molecular dynamics method and quantum mechanics method (Density FunctionalTheory method).The adsorption of CH4 on the different surfaces of the shale molecule is studied using density functional theory, and the adsorption behaviors (adsorption energy) of each adsorption site are compared, and the effects of the mineral compositions on CH4 adsorption are also analyzed.Experiments are conducted to investigate the adsorption law and sensitivities of shale gas in actual shale gas reservoir cores, the adsorption law of shale gas and other associated gases in relation to mineral composition of the core, organic carbon content, reservoir temperature and pressure are studied by measuring and analyzing the absorption of shale gas

英文关键词： shale gas；adsorption；molecular scale；Monte Carlo；DFT