Optimal CO2 allocation for enhanced oil recovery operations within carbon utilisation networks in Qatar

Abstract

Carbon capture and storage (CCS) is one of the mostefficienttechniques for reducing carbon dioxide (CO 2 ) emissions into the atmosphere. Combining CCS with enhanced oil recovery (EOR) processes is a very attractive method for carbon capture and utilisation (CCU). These operations enable CO 2 emissions to be reducedthroughgeological sequestration, whilstgenerating additional revenue from enhanced oil production due to CO 2 re-injection via EOR. In practice, mass balance and temporal features of a given location are considered when planning EOR operations. When numerous oil reservoirs are involved, it is vital to allocate available CO 2 supplies and schedule EOR operations for these reservoirs at suitable timings. As a result, CO 2 allocation and scheduling are crucial for maximising the economic benefits of EOR operations. As such, this study introduces a resource trade scheme for CO 2 integration and utilisationwithin the state Qatar, where a mixed integer linear programming (MILP) model is developed to address CO 2 allocation and schedulingbased on environmental and economic objectives. The model considersa single CO 2 source (Qatar Gas) within an multi sink scenario which ORYX GTL, Dukhan Field Well (EOR)). Two scenarios are considered to allocateCO 2 to different sinks (including EOR) to obtain the optimal solution for each scenario. The outcome of scenario 1 demonstrates that the optimal solution is to utilize 13.5Mt/y of carbon dioxide, which results in an annual profit varying from 14.3 to 42.8 billion US dollars. The maximum CO 2 utilisation occurs at Dukhan Field Well (EOR), which utilises up to 67%. Scenario 2 is implemented based on scenario 1 to further improve the model; where the profit increased annually, and the model became more sustainable.