不同成熟度页岩干酪根中CO_(2)吸附与孔隙变形的耦合机理  

Coupling Mechanism of CO_(2)Adsorption and Pore Deformation in Shale Kerogen with Different Maturities

作　　者：黄亮[1] 田宝华 徐侦耀 陈秋桔 冯鑫霓 朱海燕 杨琴 张润峰 王博文 HUANG Liang;TIAN Baohua;XU Zhenyao;CHEN Qiujie;FENG Xinni;ZHU Haiyan;YANG Qin;ZHANG Runfeng;WANG Bowen(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation/College of Energy(College of Modern Shale Gas Industry),Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]油气藏地质及开发工程全国重点实验室/成都理工大学能源学院(页岩气现代产业学院),成都610059

出　　处：《华南师范大学学报(自然科学版)》2025年第1期70-78,共9页Journal of South China Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(52204031);国家重点研发计划项目(2023YFF0614102)。

摘　　要：页岩干酪根中CO_(2)吸附会诱导孔隙变形,同时孔隙变形会影响干酪根吸附能力,CO_(2)吸附与孔隙变形的耦合特征和微观机理尚不明确。针对不同成熟度的干酪根,采用分子模拟方法开展了其在不同应变和压力条件下的CO_(2)吸附模拟;结合多孔介质力学理论确定了干酪根中CO_(2)吸附-孔隙变形耦合系数,并分析了吸附-变形耦合特征;联合干酪根孔隙结构和非键相互作用(包括静电力和范德华力),明确了CO_(2)吸附与孔隙变形的耦合机制。结果表明:页岩干酪根中CO_(2)吸附与孔隙变形的耦合系数受干酪根成熟度影响,不能直接采用煤岩有机质中结果,干酪根吸附-变形能力随成熟度增加而降低。吸附-变形耦合系数在一定压力范围内(>2 MPa)可近似为常数,未成熟干酪根在压缩变形和膨胀变形阶段的耦合系数存在明显差异。CO_(2)与干酪根的吸附作用以范德华力为主,其次为静电力。CO_(2)吸附使得干酪根孔隙度和比表面积增加,孔径分布向更大尺寸偏移。研究结果揭示了页岩干酪根中CO_(2)吸附与孔隙变形的耦合特征及微观机理,可为页岩储层CO_(2)封存效果评价提供理论指导。The adsorption of CO_(2)in shale kerogen results in the pore deformation,which,in turn,affects the adsorption capacity of kerogen.The coupling characteristics and micro-mechanisms between CO_(2)adsorption and pore deformation in shale kerogen remain unclear.For kerogen with different maturities,this study systematically simulated CO_(2)adsorption behavior under various strains and pressures using molecular simulation methods.Building on this,the coupling coefficient between CO_(2)adsorption and pore deformation in shale kerogen was quantified through poromechanical theory,uncovering its dynamic volution with kerogen maturity.Additionally,the micro-mechanisms of adsorption-deformation coupling were clarified by examining the evolution of kerogen pore structures and their non-bonded interactions(e.g.,van der Waals and electrostatic forces)with CO_(2).The findings show that the coupling coefficient between CO_(2)adsorption and pore deformation in shale kerogen is maturity-dependent,and results derived from coal organic matter are not directly transferable.Furthermore,the adsorption-deformation capacity of kerogen diminishes as maturity increases.The coupling coefficient is approximately constant within a certain pressure range(>2 MPa),and significant differences are observed in the coupling coefficients for immature kerogen during its compression and expansion stages.The adsorption interaction of CO_(2)on kerogen is mainly controlled by van der Waals forces,followed by electrostatic forces.The adsorption of CO_(2)increases the porosity and specific surface area of kerogen and induces a shift towards larger pore sizes in the pore size distribution.The results reveal the coupled characteristics and micro-mechanisms between CO_(2)adsorption and pore deformation in shale kerogen,which provide theoretical guidance for evaluating the performance of CO_(2)sequestration in shale reservoirs.

关 键 词：页岩干酪根 CO_(2)吸附 孔隙变形 耦合作用 分子模拟 

分 类 号：TE121.3[石油与天然气工程—油气勘探]