基于AFM的巫溪2井页岩储层孔隙特征研究  

Research on pore characteristics of shale reservoir in Wuxi No.2Well based on AFM

作　　者：龚卓 陈尚斌[1,2] 李学元 王慧军 GONG Zhuo;CHEN Shangbin;LI Xueyuan;WANG Huijun(School of Resources and Geosciences,China University of Mining and Technology,Xuzhou 221116,China;Key Laboratory of Coalbed Methane Resources and Accumulation Process of Ministry of Education,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221116

出　　处：《煤炭科学技术》2022年第7期216-223,共8页Coal Science and Technology

基　　金：国家自然科学基金资助项目(41772141,41972171)。

摘　　要：页岩储层孔隙是页岩气赋存和渗流的基础,但在其研究中很难将孔隙定量信息和页岩表面形貌相结合,且现有的孔隙定性、定量研究手段都存在自身的限制。为研究页岩储层孔隙特征,并将孔隙定量信息和页岩表面形貌结合,采用原子力显微镜(AFM)扫描页岩样品,利用NanoScope Analysis和Gwyddion两种软件对AFM数据进行分析,定性、定量地研究了巫溪2井龙马溪组页岩的孔隙特征,将部分结果同低温N2吸附试验所得结果进行了对比。巫溪2井龙马溪组页岩的均方根粗糙度在1.7~13.6 nm,平均粗糙度在1.3~10.7 nm,TOC(总有机碳含量)和均方根粗糙度的相关系数为0.8112,TOC和平均粗糙度的相关系数为0.9008,页岩粗糙度受显微组分尤其是有机质组分的控制;页岩孔隙多为狭缝形孔、楔形孔,主孔段位于4~6 nm和14~50 nm,平均孔径在3.9~6.6 nm波动,介孔占70%以上;孔隙截面长宽比在1.5~3.1。利用原子力显微镜获得的孔隙形貌、IUPAC分类标准的各孔径范围内的孔隙占比、平均孔径和利用低温N2吸附试验获得的结果相近;AFM测定部分样品主孔段和低温N2吸附试验结果不同。AFM和低温N2吸附试验的结果对比表明,AFM定性表征内部具有复杂结构的孔隙能力不足,对孔隙的定性测定结果较低温N2吸附试验结果直观,适于定性、定量地表征2~50 nm的孔隙特征,并且能得到传统试验手段未获得的一些重要参数,是一种潜在的重要表征方法。Shale reservoir pores are the basis for shale gas occurrence and seepage,but it is difficult to combine quantitative pore information and shale surface morphology in its research,and the existing pore qualitative and quantitative research methods have their own limits.In order to study the pore characteristics of shale reservoirs and combine the quantitative information of the pores with the surface morphology of the shale,the shale samples were scanned using atomic force microscopy(AFM),and the AFM data was analyzed using two softwares,NanoScope Analysis and Gwyddion.The pore characteristics of the Longmaxi shale in Wuxi No.2 Well were studied,and some of the results were compared with those obtained by the low-temperature N2adsorption experiment.The root-mean-square roughness of Longmaxi shale in Wuxi No.2 Well is from 1.7 to 13.6 nm,the average roughness is from 1.3 to 10.7 nm,the correlation coefficient of TOC and root-mean-square roughness is 0.8112,and the correlation coefficient between TOC and average roughness is 0.9008,the shale roughness is controlled by microscopic components,especially organic components;the shale pores are mostly slit-type pores,and wedge-shaped pores,and the main pore sections are located at 4-6 nm and 14-50 nm,The average pore diameter fluctuates in the range of 3.9-6.6 nm,and mesopores account for more than 70%;the aspect ratio of the pore section is in the range of 1.5-3.1.The pore morphology,the proportion of pores in each pore size range of the IUPAC classification standard,the average pore diameter obtained by atomic force microscopy and the results obtained by the low-temperature N2adsorption experiment are similar;the main pore sections obtained by AFM of part of samples are different from the results obtained by low-temperature N2adsorption experiments.The comparison of the results of AFM and low-temperature N2adsorption experiments shows that AFM has insufficient ability to qualitatively characterize the pores with complex structures inside,but the qualitative measurement

关 键 词：原子力显微镜 页岩 巫溪2井 孔隙结构 储层 

分 类 号：TD83[矿业工程—煤矿开采]