Predicting microemulsion phase behavior using physics based HLD-NAC equation of state for surfactant flooding

Summary Microemulsion phase behavior is crucial to surfactant flooding performance and design. In previous studies, analytical/numerical solutions for surfactant flooding were developed dependent on the classical theory of multicomponent/multiphase displacement and empirical microemulsion phase-behavior models. These phase-behavior models were derived from empirical correlations for component-partition coefficients or from the Hand-rule model (Hand 1930), which empirically represents the ternary-phase diagram. These models may lack accuracy or predictive abilities, which may lead to improper formulation design or unreliable recovery predictions. To provide a more-insightful understanding of the mechanisms of surfactant flooding, we introduced a novel microemulsion phase-behavior equation of state (EOS) dependent on the hydrophilic/lipophilic-difference (HLD) equation and the net-average curvature (NAC) model, which is called HLD-NAC EOS hereafter. An analytical model for surfactant flooding was developed dependent on coherence theory and this novel HLD-NAC EOS for two-phase three-component displacement. Composition routes, component profile along the core, and oil recovery can be determined from the analytical solution. The analytical solution was validated against numerical simulation as well as experimental study. This HLD-NAC EOS based analytical solution enables a systematic study of the effects of phase-behavior-dependent variables on surfactant-flooding performance. The effects of solution gas and pressure on microemulsion phase behavior were investigated. It was found that an increase of solution gas and pressure would lead to enlarged microemulsion bank and narrowed oil bank. For a surfactant formulation designed at standard conditions, the analytical solution was able to quantitatively predict its performance under reservoir conditions.

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Revisiting Kelvin equation and Peng–Robinson equation of state for accurate modeling of hydrocarbon phase behavior in nano capillaries

Scientific Reports ◽

10.1038/s41598-021-86075-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ilyas Al-Kindi ◽

Tayfun Babadagli

Keyword(s):

Experimental Data ◽

Surface Tension ◽

Equation Of State ◽

Phase Behavior ◽

Pore Radius ◽

Microfluidic Chips ◽

Tight Sandstone ◽

Kelvin Equation ◽

Rock Samples ◽

Robinson Equation

AbstractThe thermodynamics of fluids in confined (capillary) media is different from the bulk conditions due to the effects of the surface tension, wettability, and pore radius as described by the classical Kelvin equation. This study provides experimental data showing the deviation of propane vapour pressures in capillary media from the bulk conditions. Comparisons were also made with the vapour pressures calculated by the Peng–Robinson equation-of-state (PR-EOS). While the propane vapour pressures measured using synthetic capillary medium models (Hele–Shaw cells and microfluidic chips) were comparable with those measured at bulk conditions, the measured vapour pressures in the rock samples (sandstone, limestone, tight sandstone, and shale) were 15% (on average) less than those modelled by PR-EOS.

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Pore-Scale Simulation of Confined Phase Behavior with Pore Size Distribution and Its Effects on Shale Oil Production

Energies ◽

10.3390/en14051315 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1315

Author(s):

Jingwei Huang ◽

Hongsheng Wang

Keyword(s):

Phase Equilibrium ◽

Equation Of State ◽

Pore Size Distribution ◽

Phase Behavior ◽

Pore Size ◽

Size Distribution ◽

Critical Role ◽

Shale Oil ◽

Pore Scale ◽

Modified Equation

Confined phase behavior plays a critical role in predicting production from shale reservoirs. In this work, a pseudo-potential lattice Boltzmann method is applied to directly model the phase equilibrium of fluids in nanopores. First, vapor-liquid equilibrium is simulated by capturing the sudden jump on simulated adsorption isotherms in a capillary tube. In addition, effect of pore size distribution on phase equilibrium is evaluated by using a bundle of capillary tubes of various sizes. Simulated coexistence curves indicate that an effective pore size can be used to account for the effects of pore size distribution on confined phase behavior. With simulated coexistence curves from pore-scale simulation, a modified equation of state is built and applied to model the thermodynamic phase diagram of shale oil. Shifted critical properties and suppressed bubble points are observed when effects of confinement is considered. The compositional simulation shows that both predicted oil and gas production will be higher if the modified equation of state is implemented. Results are compared with those using methods of capillary pressure and critical shift.

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Description of Phase Behavior of Polymer Blends by Different Equation-of-State Theories. 1. Phase Diagrams and Thermodynamic Reasons for Mixing and Demixing

Macromolecules ◽

10.1021/ma00123a028 ◽

1995 ◽

Vol 28 (19) ◽

pp. 6586-6594 ◽

Cited By ~ 8

Author(s):

Bernd Rudolf ◽

Hans-Joachim Cantow

Keyword(s):

Equation Of State ◽

Polymer Blends ◽

Phase Behavior ◽

Phase Diagrams

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Study of sodium electrolytes on phase behavior of the anionic surfactant/alcohol/model oil system and its application for alkaline-surfactant flooding formulation design

Journal of Dispersion Science and Technology ◽

10.1080/01932691.2021.2017298 ◽

2021 ◽

pp. 1-10

Author(s):

Lei Ding ◽

Qianhui Wu ◽

Xuan Zhang ◽

Jijiang Ge

Keyword(s):

Phase Behavior ◽

Anionic Surfactant ◽

Surfactant Flooding ◽

Formulation Design ◽

Model Oil

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Static and Dynamic Comparison of Equation of State Solid Model and PC-SAFT for Modeling Asphaltene Phase Behavior

10.2118/180480-ms ◽

2016 ◽

Cited By ~ 8

Author(s):

Ali Abouie ◽

Mohsen Rezaveisi ◽

Saeedeh Mohebbinia ◽

Kamy Sepehrnoori

Keyword(s):

Equation Of State ◽

Phase Behavior ◽

Solid Model

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Curvature-Based Equation of State for Microemulsion-Phase Behavior

SPE Journal ◽

10.2118/194022-pa ◽

2018 ◽

Vol 24 (02) ◽

pp. 647-659 ◽

Cited By ~ 2

Author(s):

V. A. Torrealba ◽

R. T. Johns ◽

H.. Hoteit

Keyword(s):

Equation Of State ◽

Phase Behavior ◽

Oil Recovery ◽

Industrial Applications ◽

Data Availability ◽

Behavior Modeling ◽

Average Curvature ◽

Wide Range ◽

Definition Of ◽

Spheroidal Geometry

Summary An accurate description of the microemulsion-phase behavior is critical for many industrial applications, including surfactant flooding in enhanced oil recovery (EOR). Recent phase-behavior models have assumed constant-shaped micelles, typically spherical, using net-average curvature (NAC), which is not consistent with scattering and microscopy experiments that suggest changes in shapes of the continuous and discontinuous domains. On the basis of the strong evidence of varying micellar shape, principal micellar curves were used recently to model interfacial tensions (IFTs). Huh's scaling equation (Huh 1979) also was coupled to this IFT model to generate phase-behavior estimates, but without accounting for the micellar shape. In this paper, we present a novel microemulsion-phase-behavior equation of state (EoS) that accounts for changing micellar curvatures under the assumption of a general-prolate spheroidal geometry, instead of through Huh's equation. This new EoS improves phase-behavior-modeling capabilities and eliminates the use of NAC in favor of a more-physical definition of characteristic length. Our new EoS can be used to fit and predict microemulsion-phase behavior irrespective of IFT-data availability. For the cases considered, the new EoS agrees well with experimental data for scans in both salinity and composition. The model also predicts phase-behavior data for a wide range of temperature and pressure, and it is validated against dynamic scattering experiments to show the physical significance of the approach.

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