Experimental investigation of DME-water-crude oil phase behavior and PVT modeling for the application of DME-enhanced waterflooding

Due to first contact miscibility with hydrocarbons and partial miscibility with water/brine, DME has shown a significant potential for enhanced waterflooding technology that has been developed recently in Shell. To provide a solid foundation for this EOR application, understanding the phase behavior of DME-brine-oil systems is crucial - which is practically non-existent for the conditions of interest in the open literature. We perform experimental study to measure partitioning of DME between hydrocarbon and aqueous phases. We also develop a PVT model using cubic plus association (CPA) to characterize the mixture of DME, water/brine and hydrocarbons based on experimental data. Finally, we investigate the dependency of the partitioning coefficient on feed per phase and show that it decreases with increase in DME mole fraction in hydrocarbon phase while increases with increase in salinity.