Pore Structure and Multi-Scale Fractal Characteristics of Adsorbed Pores in Marine Shale:A Case Study of the Lower Silurian Longmaxi Shale in the Sichuan Basin,China  

作　　者：Haijiao Fu Detian Yan Chenpeng Yao Xianbo Su Xiaoming Wang Hu Wang Yueguo Li 

机构地区：[1]School of Earth Resources,China University of Geosciences,Wuhan,430074,China [2]Key Laboratory of Tectonics and Petroleum Resources,China University of Geosciences,Ministry of Education,Wuhan,430074,China [3]School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo,454000,China

出　　处：《Journal of Earth Science》2022年第5期1278-1290,共13页地球科学学刊（英文版）

基　　金：financially supported by the PetroChina Innovation Foundation(No.2019D-5007-0107);the National Natural Science Foundation of China(No.42172192);the National Natural Science Foundation for Young Scholars of China(No.41902173);the Fundamental Research Funds for the Central Universities(No.CUG170678);the Natural Science Foundation of Hubei Province(No.2019CFA028);the Program of Introducing Talents of Discipline to Universities(No.B14031)。

摘　　要：Exploration practice indicates that free gas is the key to the large-scale development of shale gas,while adsorbed gas is also of great significance to the sustainable development of shale gas,and thus systematic researches on absorbed pores are needed.To date,researches on pore structure and multi-scale fractal characteristics of absorbed pores in marine shale are obviously insufficient,limited the understanding of gas production behavior from shale reservoir.In this study,total organic carbon(TOC),X-ray diffraction(XRD),CH_(4) adsorption,field emission electron microscopy(FE-SEM),and low temperature gas(i.e.,CO_(2)and N_(2))adsorption/desorption analyses were conducted on 10 continuously core samples from the Lower Silurian Longmaxi shale in the Fuling region of Sichuan Basin,China.The results indicate that the TOC content of marine shale samples changes from 0.95%to 4.55%with an average of 2.62%,showing an increasing trend with the increase of burial depth;moreover,quartz and clay are the dominated mineral compositions in marine shale,and they show a certain negative correlation.FE-SEM analysis indicates that almost all pore types in marine shale are related to organic matter(OM).Hysteresis loops of marine shale samples mainly belong to Type H2,further indicating that the pores in marine shale are mainly ink-bottle pores(i.e.,OM pores);moreover,adsorption isotherms obtained from CO_(2)adsorption data all belong to typeⅠ,indicating microporous properties for all shale samples.Comprehensive analysis indicates that pore volume and pore surface area of adsorbed pores(<300 nm)is mainly provided by the pores within the pore range of 0.6–0.7,0.80–0.85,and 1.7–5.0 nm.Based on the micropore filling model and the Frenkel-Halsey-Hill(FHH)model,multiscale fractal dimensions(D1,D2,and D3)are calculated from gas adsorption data(i.e.,CO_(2)and N_(2)),corresponding to part of micropore(0.6–1.1 nm),small-mesopore(1.7–5.0 nm),big-mespore and part of macropore(5.0–300 nm),respectively.Relationships between shale co

关 键 词：adsorbed pores Pore structure Fractal dimensions Marine shale Sichuan Basin petroleum geology 

分 类 号：P618.13[天文地球—矿床学]