Geochemical reactions among CO2-fromation water-rocks can occur and affect the physical properties of the reser-voir and the CO2 trapping mechanisms during CO2 EOR process. In this paper, based on the properties of the reservoir and fluids in a typical high-temperature oil reservoir in Jilin Oilfield, a comprehensive model was established to simulate the CO2 EOR and the subsequent storage, processes, in which formation water evaporation, dissolution and diffusion of CO2 in water, CO2-water-rock geochemical reactions and variations of porosity and permeability were considered. The geochemical reactions and various CO2 trapping forms in different stages were analyzed using the model, and the influences of different CO2 injec-tion methods on EOR and CO2 storage were evaluated. The results show that, though the geochemical reactions can change reservoir porosity and permeability, their effect is not significant and most of the injected CO2 can be trapped as supercritical gas during CO2 EOR process. During CO2 storage, gaseous CO2 can be continuously converted into mineral forms due to geo-chemical reactions, which results in a reduction of reservoir pressure. A WAG ( water alternative gas injection) method can be applied to enhance oil recovery and increase CO2 storage efficiency. Further injection of CO2 after CO2 EOR process can increase the CO2 storage capacity, and simultaneously maintain the reservoir pressure.%油藏CO2驱过程中,CO2与地层水和岩石矿物发生化学反应,影响地层物性和CO2的埋存形式.基于吉林油田某高温油藏的地层及流体性质,建立考虑地层水蒸发、水中CO2溶解扩散、CO2-地层水-岩石地化反应和孔渗关系的CO2驱及埋存综合模拟模型,分析不同阶段的地化反应特征和CO2埋存形式,研究CO2注入方式对提高采收率和埋存效率的影响.结果表明:在CO2驱油阶段,地化反应对储层孔隙度和渗透率产生一定影响,但对采收率的影响较小,CO2主要以构造形式埋存于油藏内;在后续埋存阶段,气态CO2通过地化反应不断转化为矿物形式,造成地层压力下降;水气交替注入方式可提高原油最终采收率和CO2一次埋存效率,应为首选注入方式;对于其CO2埋存量的不足,可在CO2驱后注入一定的CO2进行补充,同时起到维持地层压力的作用.
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