Long Core Testing and Numerical Simulation Investigations of CO2-EOR and Geological Storage in the 6th Section of the Yanchang Formation in the Huaziping Oil Reservoir
Long Core Testing and Numerical Simulation Investigations of CO2-EOR and Geological Storage in the 6th Section of the Yanchang Formation in the Huaziping Oil Reservoir
Carbon dioxide-enhanced oil recovery(CO2-EOR)has gained increasing importance for many low-permeability and low-porosity oil reservoirs in China.In light of the national net-zero emission target,efficient CO2 storage becomes a vital consideration in the utilization of CO2-EOR techniques.Therefore,for low-permeability reservoirs,experiments involving natural core floods using long rock cores for CO2 displacement were conducted in this study.TOGA(TOUGH Oil,Gas,Aqueous)software was employed to establish a core-scale numerical model to perform model identification and validation.Sensitivity analyses were performed to assess the model's effectiveness and the impact of physical properties.The study produced some interesting results.1)Based on the gas-oil ratio at the outlet,CO2 flooding for oil recovery can be divided into four different stages:no gas observed(0～100),a minimal amount of gas(100～1 000),gas breakthrough(1 000～10 000),and significant gas breakthrough(>10 000).2)Porosity,permeability,and heterogeneity were identified as influential factors on simulation results.Therefore,these aspects should be prioritized in subsequent large-scale field models.The findings of this research serve as a foundation for parameterization in large-scale field models implemented at real sites.
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