页岩微纳米孔隙结构分形特征研究  

STUDY ON FRACTAL CHARACTERISTICS OF MICRO-NANO PORE STRUCTURE OF SHALE

作　　者：李志清 王伟[5] 王晓明 白雅伟 秦道天 赵颖 LI Zhiqing;WANG Wei;WANG Xiaoming;BAI Yawei;QIN Daotian;ZHAO Ying(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology),Chengdu 610059;Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029;University of Chinese Academy of Sciences,Beijing 100049;Institutions of Earth Science,Chinese Academy of Sciences,Beijing 100029;Henan Province Y.L.X Expressway Construction Co.Ltd.,Luoyang 471521;Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190)

机构地区：[1]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059 [2]中国科学院地质与地球物理研究所,中国科学院页岩气与地质工程重点实验室,北京100029 [3]中国科学院大学,北京100049 [4]中国科学院地球科学研究院,北京100029 [5]河南省尧栾西高速公路建设有限公司,洛阳471521 [6]中国科学院力学研究所,北京100190

出　　处：《工程地质学报》2018年第2期494-503,共10页Journal of Engineering Geology

基　　金：中国科学院战略性先导科技专项(B类)(XDB10030100,XDB10030102),国家自然科学基金(41672316,51374196),中国科学院青年创新促进会(2017092),成都理工大学地质灾害防治与地质环境保护国家重点实验室开放基金(SKLGP2016K011)资助

摘　　要：页岩气作为非常规气,是一种重要能源。页岩的孔隙结构特征是衡量与评价页岩储层存储能力与可压裂性的重要参数。选取威远海相页岩(1#)、龙马溪海相页岩(2#)、瑶曲凝灰岩(4#)以及瑶曲陆相页岩(5#,6#),进行压汞实验、氮气吸附性实验以及核磁共振实验。利用分形理论,表征孔隙结构的非均质性,揭示分形维数和孔隙结构之间的关系。结果表明:孔隙在0.1~100μm范围采用压汞实验,陆相页岩样品得到的分形维数要比海相页岩样品大;孔隙在2~200 nm范围采用氮气吸附实验,海相页岩的分形维数比陆相页岩大;相比之下,孔隙在10 nm^10μm范围采用核磁共振实验得到的焦石坝海相页岩与陆相页岩的分形维数大小比较接近。尤其是本文统计的氮气吸附实验样本中,焦石坝海相页岩的分形维数最大,即焦石坝海相页岩的微孔结构最为发育,非均质性最强。因此分形维数可作为一种用于评价页岩孔隙非均质性与储存压裂效果的重要参数。Shale gas,as one kind of unconventional gas,is an important energy supplement.The pore structure characteristic is an important index used to measure and evaluate the storage capacity and fracturing of shale reservoir.The Weiyuan marine shale(1#),Jiaoshiba marine shale(2#),Yaoqu tuff(4#)and Yaoqu continental shale(5#and 6#)are selected for tests with mercury porosimetry(MP),N 2 adsorption(NA)and nuclear magnetic resonance(NMR)devices.Based on fractal theory,the relationships between fractal dimensions and pore structure are investigated with MP,NA and NMR to characterize the pore anisotropy.The results illustrate that the fractal dimensions of continental samples 5#and 6#are bigger than that of marine sample 2#in the pore range between 0.1~100μm based on MP method.The fractal dimensions of marine sample 2#is bigger than those of continental samples 5#and 6#in the pore range of 2~200 nm based on NA method.In contrast,the max fractal dimensions(D NMR)of marine sample 2#are about equal to those of continental samples 5#and 6#in the pore range between 10 nm to 10μm by NMR method.Especially,the fractal dimensions of Jiaoshiba marine sample 2#are biggest among all the samples using NA method.The micropores of Jiaoshiba marine shale are the most development,so the heterogeneity of pore characteristic is the strongest.Therefore,the fractal dimension can be used as an important parameter to evaluate the fracturing effect of shale reservoir and the heterogeneity of pore structure.

关 键 词：页岩 孔隙结构 分形维数 压汞 氮气吸附 核磁共振 

分 类 号：P584[天文地球—岩石学]