Product Summary

IMPACTS OF LOCAL GRID REFINEMENT, CAPILLARY PRESSURE, AND RELATIVE PERMEABILITY ON EARLY INJECTION WELL BEHAVIOR DURING SIMULATION OF LARGE-DOMAIN DEDICATED CARBON DIOXIDE STORAGE

Results of large-domain carbon storage reservoir simulations conducted using a square grid initially showed early injection well pressure and rate trends inconsistent with typical carbon dioxide (CO₂), water, and gas injection well behavior measured in the field. To determine the potential cause of these differences, this simulation study was conducted to evaluate and quantify the relative effects of local grid refinement (LGR), relative permeability, and capillary pressure on long-term CO₂ injection well behavior. A large-domain (888-square mile) model of the Deadwood Formation (informally referred to as the Basal Cambrian) in the Williston Basin was used to simulate a single CO₂ injection well at two bottomhole injection pressures (BHIPs) with three different water-CO₂ relative permeability curves, both with and without capillary pressure. Without proper LGR, 12-year cumulative injected CO₂ mass is underpredicted by approximately 88% at a 90% fracture gradient BHIP. Reducing the BHIP requires smaller LGR cells to simulate expected early injection well behavior and indicates the need to review LGR for every realization of CO₂ injection, even after only changing BHIP or injection rate constraints. Error from excluding capillary pressure is observed to increase 12-year cumulative injection by 10% at a 90% fracture gradient BHIP and increases to 26% at the reduced BHIP. Finally, this study shows that relative permeability characterized by Bennion and Bachu,^1,2 provides similar simulation results compared to site-specific data at both explored BHIPs; therefore, these data can be temporarily used in place of site-specific data to accelerate the simulation-predicted CO₂ storage resource and injection rates. 1 Bennion,