Joint Optimization of Well Completions and Controls for CO2 Enhanced OilRecovery and Storage

摘要

CO2 storage through CO2 enhanced oil recovery(EOR)is considered as one of the technologies to helppromote larger scale deployment of CO2 storage because of associated economic benefits through oilrecovery,45Q tax credits and the utilization of existing infrastructure.The objective of this study is todemonstrate how optimal reservoir management and operation strategies(including well completions andcontrols)can be used to optimize both CO2 storage and oil recovery.The optimization problem was focused on jointly estimating the well completions(i.e.,fraction ofinjection/production well perforations in each reservoir layer)and CO2 injection/oil production controlsthat maximize the net present value(NPV)in a CO2 EOR and storage operation.We utilized the newlydeveloped StoSAG algorithm,one of the most efficient optimization algorithms in the reservoir managementcommunity,to solve the optimization problem.The performance of joint optimization approach wascompared with the performance of well control only optimization approach.In addition,the performanceof co-optimization of CO2 storage and oil recovery approach was compared with the performances ofmaximization of only CO2 storage and maximization of only oil recovery approaches.The optimization results showed that a joint optimization of well completions and well controls canachieve an 8.84% higher final NPV than the one obtained from the optimization of only well controls.Itwas observed that the NPV incremental for joint optimization is mainly due to the fact that the optimalwell completions and controls approach results in efficient CO2 storage and oil production from differentreservoir layers depending on the differences in individual layer properties.Comparison of co-optimization(i.e.,maximization of NPV)and maximization of only CO2 storage or only oil recovery showed that theco-optimization and maximization of only oil recovery result in significantly higher final NPV than thatobtained through maximization of only CO2 storage approach while maximization of only CO2 storage canachieve significantly higher CO2 storage in the reservoir compared to the other two scenarios.The similarresults for co-optimization and maximization of oil production are obtained because of the difference in oilrevenue compared to CO2 storage tax credit.To the best of our knowledge,this is the first study in oil/gas industry and CO2 storage community toperform joint optimization of well completions and well controls in the fields.We expect that the proposedoptimization framework will be a useful and efficient tool for field engineers to optimally manage CO2EOR projects to maximize revenue through oil recovery as well as CO2 storage by taking advantage of thenew 45Q tax law.