页岩气吸附量校正及其吸附性影响因素  

Correction calculation of shale gas absolute adsorption capacity and its influencing factors analysis

作　　者：周军平[1,2] 范茂琳 鲜学福[1,2] 杨康 陆朝晖[3] ZHOU Junping;FAN Maolin;XIAN Xuefu;YANG Kang;LU Zhaohui(State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing400044,China;School of Resources and Safety Engineering,Chongqing University,Chongqing400044,China;Key Laboratory of Shale Gas Exploration,Ministry of Land and Resources,Chongqing Institute of Geology and Mineral Resources,Chongqing400042,China)

机构地区：[1]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044 [2]重庆大学资源与安全学院,重庆400044 [3]重庆大学页岩气勘探开发国家地方联合工程研究中心,重庆400044

出　　处：《煤炭科学技术》2022年第2期154-162,共9页Coal Science and Technology

基　　金：国家自然科学基金资助项目(51774060,U19B2009);重庆市院士专项资助项目(cstc2019yszx-jcyjX0007)。

摘　　要：为探究页岩矿物组分、孔隙结构及其分形维数对页岩吸附特性的影响,开展龙马溪组、五峰组以及延长组页岩总有机碳(TOC)含量测试、X射线衍射(XRD)测试、低温N_(2)吸附测试,CH_(4)等温吸附实验,基于吸附相体积V_(a)恒定、吸附相密度ρ_(a)恒定2种方法对页岩气绝对吸附量进行了校正,并采用Langmuir模型对绝对吸附量进行了拟合,在此基础上获得了页岩矿物组分、孔隙结构以及Lang⁃muir模型参数之间的关系。结果表明:Langmuir模型能很好地拟合实验条件下CH_(4)在不同页岩上的吸附数据,且Langmuir模型对基于V_(a)恒定方法得到的页岩气绝对吸附量拟合结果精度更高。Langmuir体积V_(L)与页岩TOC、石英含量、比表面积、孔体积均呈正相关关系,与平均孔径呈负相关关系,与黏土矿物相关性较差;页岩孔隙结构分形维数D与其TOC含量、石英矿物含量、比表面积、孔体积呈正相关关系,与平均孔径呈负相关关系,与黏土矿物相关性较差;分形维数D与V_(L)呈正相关关系,与Langmuir压力P_(L)呈负相关关系,表明分形维数越大,页岩吸附能力越强。In this study,the total organic carbon(TOC)content analysis,X-ray diffraction(XRD)tests,low-temperature N_(2) adsorption tests and CH_(4) isothermal adsorption tests were carried out on the shale samples from Longmaxi,Wufeng and Yanchang formations,to ob⁃tain the relationship between the mineral composition,pore structure and its fractal dimension on adsorption characteristics of shale.Based on the two calculation methods,including the hypothesis of constant adsorbed phase volume V_(a) and constant adsorbed phase density ρ_(a),the absolute adsorption amount of shale gas was corrected and was fitted by Langmuir model,then the relationships between shale mineral composition,pore structure and Langmuir model parameters were obtained.The results show that the Langmuir model can fit well with the adsorption data of CH_(4) on different shales under the experimental conditions,and the Langmuir model has higher accuracy in fitting the absolute adsorption amount of shale gas obtained based on the hypothesis ofadsorbed phase volume V_(a) Langmuir volume V_(L) is positively cor⁃related with TOC and quartz content,specific surface area and pore volume,and is negatively correlated with the average pore diameter,and poorly correlated with clay minerals.The fractal dimension D of pore structure in shale is positively correlated with TOC content,quartz content,specific surface area and pore volume,and is negatively correlated with average pore diameter,and poorly correlated with clay minerals.The fractal dimension D is positively correlated with V_(L),and negatively correlated with Langmuir pressure P_(L),indicating that a larger fractal dimension D correspond stronger adsorption capacity of shale.

关 键 词：页岩气 吸附相密度 矿物组分 孔隙结构 分形维数 吸附特性 

分 类 号：P618.13[天文地球—矿床学] TE37[天文地球—地质学]