Dynamic modeling studies of basin-scale pressure interference and CO2 plume evolution in multi-well geologic CO2 storage

Large-scale decarbonization through carbon capture and storage (CCS) may likely involve many commercial-scale CO2 storage projects located in proximity. Large volumes of CO2 injected will elevate reservoir pressures and may lead to rapid convergence of fracture pressure thresholds. This analysis employs numerical modeling to analyze how CO2 plumes and pressure fronts evolve when CO2 is injected into a single storage formation from multiple projects located in proximity. This analysis also evaluates the extent to which injection well spacing alleviates pressure buildup in the absence of active pressure management tactics. The simulation approach was based on a single, homogenous saline aquifer in which CO2 injection occurs under a one-injector baseline case and several multi-well cases where well spacing varies. Analysis results show that the extent of pressure buildup is in the range of tens or a few hundreds of kilometers and contingent upon the defining pressure buildup demarcating the front edge. For the geological setting evaluated in this paper, our analysis suggests that without active basin pressure management strategies, commercial-scale projects would likely need to be sited far apart to avoid pressure interference from one another. Analysis results show the radius of CO2 plume varies approximately from 2 to 3 km from injection wells (each injecting 1 Mt/year for 30 years) depending on cases and modeling parameters assumed. Given the pressure interference, this paper thus draws attention to the importance of greater coordination among storage operators and regulatory stakeholders. Because this analysis assumes a very specific geologic situation, this exploratory analysis bears further investigations across other geologic situations.