CO_(2)-咸水-岩石相互作用对储层孔隙度的影响:以准噶尔盆地东沟组砂岩层为例  

The Influence of CO_(2)-Brine-Rock Interaction on Reservoir Porosity:A Case Study of Sandstone Reservoir of Donggou Formation in Junggar Basin

作　　者：金将伟 杨国栋 刘思雨 马鑫[2] 张银银 韩顺琦 JIN Jiangwei;YANG Guodong;LIU Siyu;MA Xin;ZHANG Yinyin;HAN Shunqi(College of Resources and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China;Center for Hydrogeology and Environmental Geology of China Geological Survey,Baoding 071051,Hebei,China)

机构地区：[1]武汉科技大学资源与环境工程学院,武汉430081 [2]中国地质调查局水文地质环境地质调查中心,河北保定071051

出　　处：《有色金属(冶炼部分)》2025年第2期204-216,共13页Nonferrous Metals(Extractive Metallurgy)

基　　金：国家自然科学基金资助项目(42141009);自然资源部地质环境监测工程技术创新中心开放基金项目(2022KFK1212006);企业委托项目(2022H10418)。

摘　　要：为探究实际工程情况下超临界CO_(2)注入咸水层地质封存过程中储层孔隙度的变化,考虑CO_(2)-咸水-岩石相互作用对储层孔隙度的影响。以准噶尔盆地东沟组砂岩储层为研究对象建立三维地质模型,采用全耦合方法进行多相多组分流动模拟超临界CO_(2)注入咸水层后的溶解与扩散过程。结果表明,模拟期间储层孔隙度随CO_(2)羽迁移呈现出4种不同变化趋势;温度和地层水盐度梯度变化均会改变孔隙度变化趋势。基于数据分析,发现CO_(2)-咸水-岩石相互作用抑制了CO_(2)的迁移速率,导致不同区域矿物溶解或沉淀状态不同,进而造成了对孔隙度影响的差异性;封存过程中CO_(2)的持续注入导致储层内pH降低,产生矿物溶解,进而增加了孔隙空间,其中钙长石的溶解作用最显著,后期方解石持续生成则导致孔隙度增速放缓或减小;温度升高可促进矿物反应,并导致矿物变化量的增加,进而影响储层孔隙度的变化量;高盐度地层条件下不利于地化反应发生,进而减少孔隙度的变化量。研究结果可为CO_(2)地质封存的储层多场耦合模拟、地球化学响应特征研究提供一定的技术支撑,也为CO_(2)地质封存的长期性和稳定性评价提供了理论依据。To investigate the variations in reservoir porosity during the geological storage of supercritical CO_(2)injection into saline aquifers under actual engineering conditions,the influence of CO_(2)-brine-rock interaction on reservoir porosity was considered.A three-dimensional geological model was established based on the sandstone reservoir of the Donggou Formation in the Junggar Basin,and a fully coupled method was used to simulate the dissolution and diffusion processes of supercritical CO_(2)injection into saline aquifers after multiphase and multicomponent flow.The results show that the reservoir porosity presents four different trends during the simulation period as the CO_(2)plume migrates.The change of temperature and formation water salinity gradient will change the trend of porosity change.Based on data analysis,it is found that the interaction between CO_(2)-brine-rock inhibit the migration rate of CO_(2),resulting in different mineral dissolution or precipitation states in different regions,which in turn causes differences in the impact on porosity.The continuous injection of CO_(2)during the sealing process leads to a decrease in pH value in the reservoir,resulting in mineral dissolution,which in turn increases the pore space.The dissolution of plagioclase is the most significant,and the continuous formation of calcite in the later stage leads to a slowdown or decrease in porosity growth.An increase in temperature can promote mineral reactions and lead to an increase in the amount of mineral changes,which in turn affects the amount of porosity changes in the reservoir.High-salinity formation conditions are not conducive to geochemical reactions,thereby reducing the amount of porosity change.The results of this study can provide technical support for the multi-field coupling simulation of CO_(2)geological storage reservoirs and the study of geochemical response characteristics,as well as provide theoretical basis for the long-term and stability evaluation of CO_(2)geological storage.

关 键 词：CO_(2)-咸水-岩石相互作用 孔隙度 CO_(2)地质封存 咸水层 准噶尔盆地 数值模拟 

分 类 号：F205[经济管理—国民经济]