煤田地质与勘探2025，Vol.53Issue(2)：99-106,8.DOI:10.12363/issn.1001-1986.24.09.0579
咸水层中液态与超临界CO2运移特征和封存方式
Migration characteristics and storage forms of liquid and supercritical CO2 in saline aquifers
摘要
Abstract
[Objective]CO2 storage in saline aquifers serves as a critical technology used to dramatically reduce green-house gas emissions.Owing to the low-temperature marine environment and the pressure from overlying seawater,shal-low offshore saline aquifers exhibit significantly different temperature and pressure conditions compared to onshore sa-line aquifers at equivalent burial depths,allowing CO2 to occur in a liquid state.Compared to supercritical CO2,liquid CO2 features higher density,viscosity,and solubility in formation water,which affect the CO2 migration and storage pro-cesses.Previous studies focus primarily on supercritical CO2,lacking a deep understanding of the migration and storage patterns of liquid CO2 in saline aquifers.[Methods]Considering the distinct characteristics of liquid and supercritical CO2,this study constructed a mathematical model for CO2 migration and storage under the action of buoyancy and capil-lary pressure.Using the high-precision numerical simulations of two-phase seepage,this study compared the laws of changes in the migration characteristics and storage forms of liquid and supercritical CO2 in saline aquifers after gas in-jection.[Results and Conclusions]The results indicate that compared to supercritical CO2,liquid CO2 manifested re-duced vertical migration rates and swept volumes under buoyancy-dominated conditions.After 25 a,the storage amounts of liquid CO2 in different storage forms were significantly lower than those of supercritical CO2,making it more diffi-cult to fully leverage the storage capacity of saline aquifers.Among the different CO2 storage forms,local capillary trap-ping,residual gas trapping,and solubility trapping represent 55%,40%,and 5%,respectively,with the CO2 phase states posing minor impacts on the storage forms.An increase in geothermal gradient enhanced the vertical migration and swept volume of liquid CO2,the CO2 storage amounts of different storage forms,and the utilization efficiency of the storage capacity of saline aquifers.At the same burial depths,supercritical CO2 displayed significantly different migra-tion characteristics and storage amounts in onshore and offshore saline aquifers.The inhibited vertical migration of su-percritical CO2 in offshore saline aquifers reduced the CO2 storage amounts of local capillary trapping and residual gas trapping,hampering the effective utilization of the storage capacity of saline aquifers.The results of this study can serve as a guide for efficient CO2 storage in onshore and offshore saline aquifers.关键词
咸水层/CO2地质封存/相态/浮力/毛管力/封存方式Key words
saline aquifer/CO2 geological storage/phase state/buoyancy/capillary force/storage form分类
石油、天然气工程引用本文复制引用
彭玺伊,王延永,李嵩,王晓光,崔国栋,何勇明..咸水层中液态与超临界CO2运移特征和封存方式[J].煤田地质与勘探,2025,53(2):99-106,8.基金项目
四川省科技计划项目(2022YFSY0008) （2022YFSY0008）
国家自然科学基金项目(52404021) （52404021）
