A contrasting analysis of CO2 and N2 foam flood for enhanced oil recovery and geological storage of CO2

Abstract

Foam flooding using CO2 has emerged as a promising method for both enhanced oil recovery (EOR) and the storage of CO2 in geological reservoirs. This study conducts a thorough analysis of the behavior of CO2 and N2 foams in bulk and porous media, utilizing bubble-scale analyses and foam flooding experiments. The study compares the foamability and longevity of CO2 and N2 foams, with findings indicating that N2 foam bubbles tend to be smaller and less varied in size than CO2 foam bubbles, leading to increased foam stability. Additionally, the study compares the half-lives of CO2 and N2 foams generated through sparging and winding methods, showing that N2 foam has half-lives 22 and 10 times greater than CO2 foam when produced using the sparging and winding methods, respectively. Furthermore, CO2 foam generated through the sparging method had a lower foaming volume than N2 foam due to CO2's solubility. In the foam flooding experiments, N2 foam proved more effective in recovering oil from porous media than CO2 foam, thus demonstrating the effectiveness of the foam injection procedure. These results offer valuable insights into the differing performance of N2 and CO2 foam floods for EOR and CO2 geological storage.