Influence of Reservoir Spatial Heterogeneity on a Multicoupling Process of CO2Geological Storage

As a means of delaying climate change, injecting carbon dioxide (CO2) into geological structures can be an effective carbon capture, utilization, and storage (CCUS) strategy. All geological structures are naturally spatial heterogeneity, which can significantly affect fluid flow and heat transfer, thereby affecting CO2 storage. We modeled fluid flow and heat transfer in 12 CO2 storage scenarios with spatially heterogeneous reservoirs using a thermal-hydraulic-mechanical (THM) coupled model of a 3D wellbore-reservoir system. CO2 injectability and distribution uniformity were studied in relation to reservoir vertical heterogeneity and interlayers. The optimization method of engineering parameters is discussed. Positive rhythm reservoirs exhibit more uniform CO2 distribution laterally under gravity than reverse rhythm reservoirs. In high permeability ratio reservoirs, the low-temperature zone has a longer transfer distance and CO2 is more likely to be injected, but channeling is prone to occur. Reservoir porosity has little effect on reservoir CO2 injectability and temperature distribution. The interlayers will weaken the influence of gravity and reduce the CO2 injectability while providing additional storage volume. Injecting CO2 at a lower temperature and mass flow will increase injectability. The uniform distribution of CO2 laterals is most effectively improved by hydraulic fracturing. Using low thermal conductivity materials for the wellbore insulation to reduce heat replenishment from the surrounding formation is critical.