Challenges in modeling microemulsion phase behavior

Abstract

AbstractModeling the complex phase behavior of microemulsions has been the subject of research for decades for hydrocarbon oil and organic contaminant recoveries. The empirical Hand model has been the standard scheme for calculating phase behavior in reservoir simulators. On the other hand, the hydrophilic–lipophilic deviation (HLD) model in conjunction with the net curvature and average curvature models (HLD‐NAC) has provided some theoretical basis for modeling microemulsions. While the HLD‐NAC has been successful in describing salinity scans, only recently an HLD‐NAC approach was devised that could represent binodal curves with physical behavior, resulting in a succession of new microemulsion flash algorithms. While these new algorithms claimed to include the effects of cosolvent, there are only few works in the literature, which give an in‐depth description of the cosolvent modeling. Furthermore, to the best of our knowledge, no work has investigated the capability of HLD‐NAC models for predicting data for different cosolvent concentrations nor did any work present a comprehensive study of the application of HLD‐NAC against Hand model for formulations including cosolvents. This paper aims to contribute in filling such gap. We modify different versions of the new HLD‐NAC approach with physical binodal curves by providing more flexibility into controlling the binodal heights with the cosolvent concentration and investigate how well they can calibrate and predict data. Experimental data sets were considered here. The results suggest that some of the HLD‐NAC approaches produced negative solubilization ratios and the Hand model gave better predictions of the ternary diagram for extreme salinity values.