An Integrated Framework for Optimizing CO₂ Sequestration and Enhanced Oil Recovery

CO₂-enhanced oil recovery (CO₂-EOR) is a technique for commercially producing oil from depleted reservoirs by injecting CO₂ along with water. Because a large portion of the injected CO₂ remains in place, CO₂-EOR is an option for permanently sequestering CO₂. This study develops a generic integrated framework for optimizing CO₂ sequestration and enhanced oil recovery based on known parameter distributions for a depleted oil reservoir in Texas. The framework consists of a multiphase reservoir simulator coupled with geologic and statistical models. An integrated simulation of CO₂–water–oil flow and reactive transport is conducted, followed by a global sensitivity and response surface analysis, for optimizing the CO₂-EOR process. The results indicate that the reservoir permeability, porosity, thickness, and depth are the major intrinsic reservoir parameters that control net CO₂ injection/storage and oil/gas recovery rates. The distance between injection and production wells and the sequence of alternating CO₂ and water injection are the significant operational parameters for designing a five-spot CO₂-EOR pattern that efficiently produces oil while storing CO₂. The results from this study provide useful insights for understanding the potential and uncertainty of commercial-scale CO₂ sequestrations with a utilization component