Numerical simulation and optimization of CO2 utilization for enhanced oil recovery from depleted reservoirs

Due to concerns about rising CO2 emissions from fossil fuel power plants, there is strong emphasis on the development of an economical method for Carbon Capture Utilization and Storage (CCUS). One area of current interest in CO2 utilization is the Enhanced Oil Recovery (EOR) from depleted reservoirs. The efficiency of the oil extraction is highly dependent on the CO2 injection rate and injection pressure. Before large scale deployment of this technology can occur, it is important to understand the mechanisms that can maximize the oil extraction efficiency as well as the CO2 sequestration capacity by optimizing these injection parameters. In this paper, numerical simulations of subsurface flow in an EOR system is conducted using the multiphase flow solver package COZView/COZSim developed by Nitec, LLC. The CO2 injection is optimized for both constant rate and pressure-limited injection scenarios using a genetic algorithm based optimizer integrated with COZSim, and the effect of recycled gas is investigated. Optimization of the EOR system results in an increased recovery factor with a more efficient utilization of injected CO2. The results of this study pave the way for future optimization of other systems such as Enhanced Gas Recovery, Enhanced Water Recovery, and Enhanced Geothermal Systems that are currently being considered for CCUS. (C) 2016 Elsevier Ltd. All rights reserved.