煤田地质与勘探2025，Vol.53Issue(12)：13-20,8.DOI:10.12363/issn.1001-1986.25.05.0327
不同孔隙结构饱水砂岩CO2驱替特征
CO2-water displacement characteristics of saturated sandstones with different pore structures
摘要
Abstract
[Objective]The pore structures of clastics play a crucial role in assessing the potential of saline aquifers for geologic CO2 sequestration.Current studies on pore structures during CO2 sequestration focus primarily on artificial cores.However,compared to artificial cores,natural cores feature more complex pore size distributions and stronger het-erogeneity.[Methods]This study examined a natural core from deep reservoirs in the Ordos Basin and two artificial cores with different porosities through CO2-water displacement experiments under water-saturated conditions.Using a nuclear magnetic resonance(NMR)analysis and imaging system for multiphase fluid displacement,this study analyzed the impacts of pore structures(pore heterogeneity)on CO2-water displacement in these cores.[Results and Conclu-sions]The artificial cores with porosities of 5%and 15%exhibited CO2-water displacement efficiencies of 67.09%and 46.71%,respectively,whereas the natural core with a porosity of 15%displayed a displacement efficiency of 37.67%.The NMR-derived transverse relaxation time(T2)spectra of the natural core showed a unimodal pattern,suggesting strong heterogeneity.In contrast,the T2 spectra of artificial cores manifested bimodal patterns,with uniform pore size distributions and low residual water saturation.Notably,a lower porosity corresponded to high pore connectivity,which allowed for sufficient contact between CO2 and the core.This characteristic effectively reduced interfacial tension and significantly enhanced CO2-water displacement efficiency.Compared to the artificial core with the same porosity,the natural counterpart showed significantly reduced CO2-water displacement efficiency due to its strong heterogeneity,with residual water occurring predominantly in small pores.Therefore,in the assessment of the potential of clastic reservoirs for CO2 sequestration,it is necessary to thoroughly consider the impact of core heterogeneity and preferentially utilize natural cores or heterogeneous artificial cores in CO2-water displacement experiments.This will help predict CO2 se-questration behavior more accurately and avoid overestimated CO2 sequestration efficiency parameters arising from the application of artificial cores made of homogeneous materials.The results of this study will provide a theoretical basis and experimental support for siting,potential assessment,and injection scheme design for geologic CO2 sequestration in saline aquifers.关键词
CO2地质封存/核磁共振/孔隙结构/CO2驱替效率Key words
geologic CO2 sequestration/nuclear magnetic resonance(NMR)/pore structure/CO2-water displacement ef-ficiency分类
天文与地球科学引用本文复制引用
刘廷,李景霖,李铱,淡文栋,刁玉杰,马鑫..不同孔隙结构饱水砂岩CO2驱替特征[J].煤田地质与勘探,2025,53(12):13-20,8.基金项目
地球深部探测与矿产资源勘查国家科技重大专项项目(2024ZD1004300) （2024ZD1004300）
中国地质调查局地质调查项目(DD20221818,DD20242531) （DD20221818,DD20242531）
