Carbon Dioxide Applications for Enhanced Oil Recovery Assisted by Nanoparticles: Recent Developments

Carbon dioxide (CO₂) in enhanced oil recovery (EOR) has received significant attention due to its potential to increase ultimate recovery from mature conventional oil reserves. CO₂-enhanced oil recovery (CO₂-EOR) helps to reduce global greenhouse gas emissions by sequestering CO₂ in subterranean geological formations. CO₂-EOR has been exploited commercially over recent decades to improve recovery from light and medium gravity oil reservoirs in their later stages of development. CO₂ tends to be used in either continuous flooding or alternated flooding with water injection. Problems can arise in CO₂-flooded heterogeneous reservoirs, due to differential mobility of the fluid phases, causing viscous fingering and early CO₂ penetration to develop. This study reviews the advantages and disadvantages of the techniques used for injecting CO₂ into subsurface reservoirs and the methods adopted in attempts to control CO₂ mobility. Recently developed methods are leading to improvements in CO₂-EOR results. In particular, the involvement of nanoparticles combined with surfactants can act to stabilize CO₂ foam, making it more effective in the reservoir from an EOR perspective. The potential to improve CO₂ flooding techniques and the challenges and uncertainties associated with achieving that objective are addressed.