Influence of Reservoir Spatial Heterogeneity on a Multicoupling Process of CO<sub>2</sub>Geological Storage
Xinyuan Gao, Shenglai Yang, Bin Shen, Lerao Tian, Shuai Li, Xing Zhang, Jiatong Wang
Abstract
As a means of delaying climate change, injecting carbon dioxide (CO 2 ) 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 CO 2 storage. We modeled fluid flow and heat transfer in 12 CO 2 storage scenarios with spatially heterogeneous reservoirs using a thermal-hydraulic-mechanical (THM) coupled model of a 3D wellbore-reservoir system. CO 2 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 CO 2 distribution laterally under gravity than reverse rhythm reservoirs. In high permeability ratio reservoirs, the low-temperature zone has a longer transfer distance and CO 2 is more likely to be injected, but channeling is prone to occur. Reservoir porosity has little effect on reservoir CO 2 injectability and temperature distribution. The interlayers will weaken the influence of gravity and reduce the CO 2 injectability while providing additional storage volume. Injecting CO 2 at a lower temperature and mass flow will increase injectability. The uniform distribution of CO 2 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.