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

Carbon dioxide (CO 2 ) in enhanced oil recovery (EOR) has received significant attention due to its potential to increase ultimate recovery from mature conventional oil reserves. CO 2 -enhanced oil recovery (CO 2 -EOR) helps to reduce global greenhouse gas emissions by sequestering CO 2 in subterranean geological formations. CO 2 -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 2 tends to be used in either continuous flooding or alternated flooding with water injection. Problems can arise in CO 2 -flooded heterogeneous reservoirs, due to differential mobility of the fluid phases, causing viscous fingering and early CO 2 penetration to develop. This study reviews the advantages and disadvantages of the techniques used for injecting CO 2 into subsurface reservoirs and the methods adopted in attempts to control CO 2 mobility. Recently developed methods are leading to improvements in CO 2 -EOR results. In particular, the involvement of nanoparticles combined with surfactants can act to stabilize CO 2 foam, making it more effective in the reservoir from an EOR perspective. The potential to improve CO 2 flooding techniques and the challenges and uncertainties associated with achieving that objective are addressed.