An Integrated Flow-Geomechanical Analysis of Flue Gas Injection in Cranfield

Lu, Xueying (The University of Texas at Austin) | Lotfollahi, Mohammad (The University of Texas at Austin) | Ganis, Benjamin (The University of Texas at Austin) | Min, Baehyun (Ewha Womans University) | Wheeler, Mary F. (The University of Texas at Austin)



CO2 capture and sequestration in subsurface reserves are expensive processes. Flue gas can be directly injected into the oil and gas reservoirs to eliminate the cost of CO2 separation from power plant emissions and simultaneously enhance hydrocarbon production that may offset the cost of gas compression. However, gas injection in subsurface resources is often subject to poor volumetric sweep efficiency caused by low viscosity and low density of the injection fluid and formation heterogeneity. This paper aims to study gas mobility control techniques of water alternating gas (WAG) and foam in Cranfield and characterize key operational parameters to the success of the process. A coupled compositional flow and geomechanics simulator, IPARS, is used to accurately simulate the underlying physical processes, with a field scale numerical model, over the desired time-span. We map flow patterns to identify risks of leakage due to interactions of viscous, gravitational, and capillary forces. A hysteretic relative permeability model enables modeling local capillary trapping. Foam mobility control technique is examined to investigate the eminent level of CO2 capillary trapping by an implicit texture foam model. The WAG and foam injection process are optimized for the number of cycles, length of the cycles using the genetic algorithm (GA) in the UT optimization toolbox. The coupled flow-mechanics model can detect the effect of the plausible interaction of geomechanics and fluid flow on CO2 plume extension. Field-scale simulations indicate that during WAG and foam processes, the oil recovery increased significantly and CO2 storage increased by 30% and 49% of during the injection spam compared to continuous gas flooding, respectively. Optimized foam process saved 25% water and surfactant consumption comparing to base case foam processes while achieving approximately the same oil recovery.