Simulation Study of Different Modes of Miscible Carbon Dioxide Flooding

Carbon dioxide flooding has been applied worldwide as a successful enhanced oil recovery. Carbon dioxide flooding may be applied as a continuous injection or as water-alternating-gas (WAG) process. Optimization of the injection mode of carbon dioxide is important for economical field application. This paper focuses on using a fully compositional simulation model for “AEB-3C” sandstone oil reservoir of one of the Western Desert oil fields in Egypt to predict the impact of CO₂ miscible flooding on the reservoir oil recovery and net present value (NPV), to define the best mode of operation that is straight CO₂ injection or water alternating gas (WAG) processes and to show the difference between pure and impure CO₂. Moreover, several sensitivity runs were done on the oil price to show minimum profitable value of oil price when applying such a tertiary method in the subject field.The reservoir under study has been producing under a successful water flooding project since May-2010. The recovery factor by the end of water flooding project is predicted as 32%. CO₂ flooding processes have started by the end of water flooding. A significant increase in the oil recovery factor was noticed due to applying this method; it reached up to 57%. Comparisons between different modes of operations were shown which showed better results when applying WAG process than that with straight CO₂ injection. Moreover; sensitivities were done on the cycle periods in WAG processes and showed increase in the recovery factor with shortening the cycle periods. In addition to a comparison between pure and impure CO₂ which showed very close results.