Inclusion of variable characteristic length in microemulsion flash calculations

D. Magzymov, R. T. Johns

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Recent developments in predicting microemulsion phase behavior for use in chemical flooding are based on the hydrophilic-lipophilic deviation (HLD) and net-average curvature (NAC) equation-of-state (EoS). The most advanced version of the HLD-NAC EoS assumes that the three-phase micelle characteristic length is constant as parameters like salinity and temperature vary. In this paper, we relax this assumption to improve the accuracy and thermodynamic consistency of these flash calculations. We introduce a variable characteristic length in the three-phase region based on experimental data that is monotonic with salinity or other formulation variables, such as temperature and pressure. The characteristic length at the boundary of the three-phase region is then used for flash calculations in the two-phase lobes for Winsor type II-/II+. The functional form of the characteristic length is made consistent with the Gibbs phase rule. The improved EoS can capture asymmetric phase behavior data around the optimum, whereas current HLD-NAC based models cannot. The variable characteristic length formulation also resolves the thermodynamic inconsistency of existing phase behavior models that give multiple solutions for the optimum. We show from experimental data and theory that the inverse of the characteristic length varies linearly with formulation variables. This important result means that it is easy to predict the characteristic length in the three-phase region, which also improves the estimation of surrounding two-phase lobes. This improved physical understanding of microemulsion phase behavior should greatly aid in the design of surfactant blends and improve recovery predictions in a chemical flooding simulator.

Original languageEnglish (US)
Title of host publicationECMOR 2020 - 17th European Conference on the Mathematics of Oil Recovery
PublisherEuropean Association of Geoscientists and Engineers, EAGE
ISBN (Electronic)9789462823426
DOIs
StatePublished - 2020
Event17th European Conference on the Mathematics of Oil Recovery, ECMOR 2020 - Virtual, Online
Duration: Sep 14 2020Sep 17 2020

Publication series

NameECMOR 2020 - 17th European Conference on the Mathematics of Oil Recovery

Conference

Conference17th European Conference on the Mathematics of Oil Recovery, ECMOR 2020
CityVirtual, Online
Period9/14/209/17/20

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geotechnical Engineering and Engineering Geology
  • Energy Engineering and Power Technology

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