Optimal control of ICV's and well operating conditions for the water-alternating-gas injection process

Water-alternating-gas (WAG) injection is a well known enhanced-oil-recovery (EOR) method in the oil industry. In a previously published paper, we concluded that the estimated net-present-value (NPV) of WAG flooding can be improved significantly by applying life-cycle production optimization. However, when reservoir layers have significantly different petro-physical properties, WAG can result in early breakthrough of the injected water and/or injected gas in layers with unfavorable physical characteristics. Thus, the production optimization technology we used previously may result in a lower NPV or cumulative oil produced than can be obtained if we are able to control injection and/or production rates on a layer-by-layer base. Recently, intelligent or smart completions, such as Inflow Control Valves (ICVs), have been used to optimize well performance. When ICVs are installed in wells, it allows us to optimize the production/injection well controls of perforated segments along the wellbore to maximize NPV or sweep efficiency and water and/or gas breakthrough. In this work, we consider smart completions for both injection and production wells. We optimize the well controls (rates or pressures) and ICV settings simultaneously and compare the NPV obtained by this process with the NPV obtained by optimizing only well controls and with the NPV generated by optimizing only ICV settings.