Injecting CO2 into geological formations can effectively slow down CO2 emissions. However, during the injection process, the physical properties of CO2 in the wellbore and reservoir change significantly, which will greatly affect the CO2 geological storage effect, and even cause injection difficulties or leakage, and the risk of hydrate formation. Therefore, a wellbore-reservoir-thermo-hydro-mechanical (WR-THM) fully coupled model is established. The model considers the heat transfer between the wellbore and the surrounding formation, the coupling between the wellbore and the target reservoir, and the THM coupling process of various fluids in the reservoir. The CO2 storage effect and possible risks under different engineering parameters were studied. The research results show that when the injection temperature is -10Â°C, there is a risk of hydrate formation at the bottom hole. Increasing the injected mass flow will greatly reduce the CO2 injection capacity. Low-permeability reservoirs are not easy to inject, and CO2 seeps uncontrollably into cap rock and base rock. The research results provide theoretical support for the safe and efficient geological storage of CO2.
Keywords CO2 storage, CCUS, wellbore fluid flow and heat transfer, multiphase flow and heat transfer in porous media, numerical simulation