Probabilistic Analysis of CO2 Storage Mechanisms in a CO2-EOR Field Using Polynomial Chaos Expansion
Depleted oil fields are already used for storing CO2 via injection of CO2 for enhanced oil recovery (CO2-EOR). Such storage is an outcome of CO2-EOR, albeit not necessarily by design. A next step would be intentional storage via post-EOR CO2 injection. Following injection for EOR or post-EOR, CO2 may be trapped by dissolution in the oil or aqueous phases, or remain in the supercritical CO2 phase. Forecasting the nature of trapping and the ultimate CO2 distribution in a reservoir is hindered by uncertainty in reservoir properties. The purpose of this study is to develop and apply reduced order models (ROMs) integrated with Monte Carlo simulations to quantify the three primary types of storage mechanisms in an active CO2-EOR field, including oil solubility trapping (oil phase), aqueous solubility trapping (aqueous phase), and hydrodynamic trapping (CO2 in supercritical phase).