Analysis and optimization of energy flow in the full chain of carbon dioxide capture and oil recovery

Abstract

AbstractCO2 capture is a process with a high energy consumption, and its large-scale implementation should be based on comprehensive analysis of its impact on the energy, economy, and environment. The process of injecting CO2 into existing oil fields is a well-known enhanced oil recovery (CO2-EOR) technique. Using CO2 as a working fluid to recover oil can compensate for the energy consumption of the capture and transport processes, increasing the feasibility of CO2 capture while achieving carbon sequestration. In this study, a full-chain CO2 capture, utilization, and storage (CCUS) system based on the post-combustion capture method is deconstructed and coupled. A full-chain energy consumption calculation software is developed, and optimization analysis of the energy consumption system is conducted. The energy budget of the oil displacement utilization is deconstructed, and the advantages of the water alternating gas (WAG) method are clarified from an energy budget point of view. The analysis reveals that the benefits of CO2-EOR are far greater than the energy consumption of other CCUS processes, and CCUS-EOR is a CO2 utilization method with positive energy benefits. Based on the simulation of the effects of N2 and CH4 on the recovery factor, a multi-well combined injection-production method is proposed, and the reasons for increasing profit are analyzed.