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

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