Total Neutron Scattering Measurements of Supercritical CO2 Injection in Limestones: Monitoring the Enhanced Oil Recovery with Additives

Carbon dioxide is widely used in Enhanced Oil Recovery (EOR). CO2-EOR can play an important role in the reduction of the global emissions of greenhouse gases because CO2 either remains sequestered underground in geologic formations or is recaptured and reinjected in a subsequent EOR project. Recently we monitored the CO2-EOR process at the nanoscale by injection of supercritical CO2 into a limestone sample loaded with decane. The neutron profiles showed directly the decane recovery and unique information was also obtained about the structural properties of confined CO2 and about the pore accessibility to CO2. We are now proposing to evaluate the additive performance during the recovery process. The phase behavior and the molecular structure of the confined CO2 mixture will be mapped during the evolution of the process and will be related to the potentiality for enhanced oil recovery.