Volume 65

Effect of Water Saturation on Oil Recovery and COâ‚‚ Storage during Hot Flue gas flooding Yuan Yuan, Renbao Zhao, Guangsen Zhu, Jiaying Wang, Bin Liu

Abstract

Carbon dioxide capture, utilization, and storage (CCUS) technology is a key pathway for achieving sustainable low-carbon utilization of fossil energy. Currently, the coupled development of CCUS and enhanced oil recovery (EOR) has made preliminary progress and is moving towards large-scale engineering applications. To balance resource maximization and carbon reduction goals, this paper investigates the impact of different water saturations (0%, 40%, 60%) on thermal propagation, recovery rate, and CO₂ storage behavior by preheating the flue gas to 300 °C before injecting it into a sandpack tube (ST). The results indicate that at a water saturation of 40%, the average temperature change rate, standard deviation, and coefficient of variation are minimized, suggesting that the synergistic effect of steam and flue gas effectively enhances heat transfer efficiency and extends the advance distance of the thermal front. Under this condition, the ultimate oil recovery and CO₂ storage are improved to 72.2% and 17.7%, respectively, significantly better than the cases of no water and high water content. Moderate water content promotes oil recovery efficiency and carbon storage capacity through a synergistic mechanism involving viscosity reduction, improved steam convective heat transfer, and gas swelling. This study clarifies the optimal range of water content in the thermal flue gas flooding (FGF) process and provides support for field flue gas reinjection and in-situ storage.

Keywords FGF, Water saturation, Storage, CCUS, EOR