Efficient Tracking of Vapor-Liquid-Aqueous-Equilibrium/Liquid-Liquid-Aqueous-Equilibrium (VLAE/LLAE) Phase Boundaries

This short communication introduces a phase-boundary tracking method that is tailored to capture the vapor–liquid-aqueous/liquid–liquid-aqueous three-phase boundaries in both pressure–temperature and pressure-composition phase diagrams. This method is applied to several reservoir fluid mixtures that exhibit four-phase vapor–liquid–liquid-aqueous equilibria. Our findings reveal that the phase boundaries identified by this tracking method converge at the apex of the vapor–liquid–liquid-aqueous four-phase region. At this apex, the compositions of the vapor phase and the CO2-riched liquid phase become identical, indicating the pinching out of the four-phase region.