Using Simplified Local Density/ Peng-Robinson Equation of State to Study the Effects of Confinement in Shale Formations on Phase Behavior

2014 ◽  
Author(s):  
Yixin Ma ◽  
Ahmad Jamili
Keyword(s):  
Equation Of State ◽  
Phase Behavior ◽  
Local Density ◽  
Shale Formations ◽  
Robinson Equation

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

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.

Analysis of various approaches to accurately prediction of phase equilibrium of binary helium systems based on the Peng-Robinson equation of state

2020 ◽  
pp. 117-126
Author(s):  
V.L. Malyshev ◽  
◽  
E.F. Moiseeva ◽  
Keyword(s):  
Phase Equilibrium ◽  
Equation Of State ◽  
Phase Behavior ◽  
Binary Interaction ◽  
Binary Interaction Parameter ◽  
Multicomponent Systems ◽  
Interaction Coefficients ◽  
Acentric Factor ◽  
Robinson Equation

The paper presents a detailed algorithm for calculating the vapor-liquid phase equilibrium for multicomponent systems based on the Peng-Robinson equation of state. Various approaches are considered that make it possible to improve the quality of predicting phase equilibrium by the example of eight binary helium systems containing nitrogen, argon, carbon dioxide, methane, ethane, propane, isobutane, and n-butane. The influence of the acentric factor and the binary interaction parameter on the accuracy of the helium systems phase behavior predicting is analyzed. The optimal interaction coefficients for the presented systems are found under the assumption that this parameter does not depend on temperature. The temperature range of applicability of various approaches is determined, which makes it possible to maximize the description of the phase behavior of helium systems.

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