CO_(2)纯度对咸水层碳封存过程中残余水的影响  

Effects of CO_(2) Purity on Residual Water During Carbon Sequestration in Deep Saline Aquifers

作　　者：胡智凯 李铱 索瑞厅 刁玉杰[3] 李琦[2] 马鑫[3] HU Zhikai;LI Yi;SUO Ruiting;DIAO Yujie;LI Qi;MA Xin(MOE Key Laboratory of Coastal Civil Engineering Structure and Safety,School of Civil Engineering,Tianjin University,Tianjin 300350,China;State Key Laboratory of Geotechnical Mechanics and Engineering,Wuhan Institute of Geotechnical Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;Key Laboratory of Carbon Dioxide Geological Storage,Hydrogeological and Environmental Geological Survey Center of China Geological Survey,Baoding 071051,China)

机构地区：[1]天津大学建筑工程学院滨海土木工程结构与安全教育部重点实验室,天津300350 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071 [3]中国地质调查局水文地质环境地质调查中心二氧化碳地质储存重点实验室,保定071051

出　　处：《高校地质学报》2023年第1期57-65,共9页Geological Journal of China Universities

基　　金：岩土力学与工程国家重点实验室开放基金(SKLGME021010);国家自然科学基金(41702251)联合资助。

摘　　要：CO_(2)在地下深部咸水含水层的封存过程中,岩石孔隙内形成的残余水对CO_(2)可注入性、封存量及安全性都有负面影响,因此深入探究各因素影响下残余水的形成演化具有重要意义。文章利用取自鄂尔多斯盆地深部储层的天然岩心,在40℃和8 MPa的实验条件下利用3种纯度的CO_(2)(99.999%CO_(2)、75%CO_(2)+25%N_(2)以及50%CO_(2)+25%N_(2))进行饱水岩心驱替实验,以探究CO_(2)纯度对残余水的影响。实验表明,在3种CO_(2)纯度下的岩心驱替实验中,达到突破点和排水终点所需时间排序均为:99.999%CO_(2)<75%CO_(2)+25%N_(2)<50%CO_(2)+50%N_(2);不可再降残余水饱和度大小排序为:99.999%CO_(2)<75%CO_(2)+25%N_(2)<50%CO_(2)+25%N_(2)。分析发现,CO_(2)纯度变化会导致界面张力、湿润性以及黏度比等两相流系统重要性质的变化。通过对LogCa-LogM驱替稳定性图进行分析,确定了毛细力是影响本实验结果的主导因素。研究结果对不同条件下残余水饱和度的预测以及CO_(2)封存量的评价等方面有重要价值。During the process of CO_(2)being injected into deep saline aquifers,residual water formed in rock pore has negative impacts on CO_(2)injectability,storage capacity and safety.Therefore,it is important to investigate the formation and evolution of residual water under various influencing factors.In this study,natural rock core taken from the deep reservoirs of the Ordos Basin were used to conduct core-flooding experiments using 3 sets of CO_(2)purity(99.999%CO_(2),75%CO_(2)+25%N_(2)and 50%CO_(2)+25%N_(2))at 40℃and 8 MPa to investigate the effect of CO_(2)purity on residual water.The experimental results show that the order of time required to reach the breakthrough point and the drainage endpoint are,99.999%CO_(2)<75%CO_(2)+25%N_(2)<50%CO_(2)+50%N_(2);the order of the irreducible water saturations is:99999%CO_(2)<75%CO_(2)+25%N_(2)<50%CO_(2)+25%N_(2).The analysis revealed that changes in CO_(2)purity lead to changes of important properties in two-phase floods,such as interfacial tension,wettability,and viscosity ratio.By analyzing the LogCa-LogM displacement stability diagram,the capillary force was determined to be the dominant factor affecting the results of experiments.This study is of great value for predicting residual water saturation under various conditions and evaluating CO_(2)sequestration capacity.

关 键 词：CO_(2)地质封存 深部咸水含水层 残余水饱和度 CO_(2)纯度 

分 类 号：X701[环境科学与工程—环境工程]