Thermodynamically consistent criteria for developing reliable equation of state model for compositional simulation

Jhalendra, Rajak Kumar; Kumar, Ashutosh

doi:10.1016/j.fuel.2018.07.047

Cited by 5 publications

(4 citation statements)

References 73 publications

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“…Usually, a more negative difference of the Gibbs free energy stands for a better miscible state. 43 Table 3 summarizes the current predictions and correlations related to MMP. Table 3 shows that the main factors affecting MMP are the reservoir fluid composition, injected gas, and reservoir temperature.…”

Section: Introductionmentioning

confidence: 99%

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HLD-Based Formulation Prediction for Degassed Oil with Equivalent Minimum Miscibility Pressure

Wang,

Zhao,

Guo

et al. 2024

Energy Fuels

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Shale cores, with their ultralow permeability, often require pressurization for saturation with target fluids, as flowthrough saturation is inefficient. This saturation method, when applied by using live oil, leads to fluid loss during core transfer and system vacuuming in subsequent experimental steps. As a result, most shale-related experiments utilize degassed oils, typically dead oil or kerosene. However, researchers account for only density or viscosity similarities in degassed oil preparation, missing key aspects of the gas injection mechanism. This study focuses on the representativeness of degassed oil and develops a procedure to prepare degassed surrogate oil that accurately replicates the live oil's minimum miscibility pressure (MMP). We propose a predictive oil formulation procedure based on thermodynamic similarities between oil/gas miscible systems and oil/water middle-phase microemulsion systems under the hydrophilic−lipophilic deviation (HLD) theory. This procedure, validated with real reservoir oil samples, uses liquid light hydrocarbons to reduce the equivalent alkane carbon number (EACN) of dead oil for surrogate oil preparation. EACN for dead, live, and surrogate oils was determined through slim tube and microemulsion phase behavior experiments. Light hydrocarbon addition quantities were estimated by linear EACN mixing. The surrogate oil's MMP, tested against CO 2 in slim tube experiments and verified through salinity scanning phase behavior experiments, was 27.83 MPa, closely matching the live oil's MMP of 28.15 MPa. These results validate the predictivity of our procedure, eliminating trial and error in adjusting light hydrocarbon volumes. The surrogate oil's lack of dissolved gases addresses fluid loss issues during rock core transfers, solving saturation and transfer challenges in tight rock core experiments.

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Section: Introductionmentioning

confidence: 99%

“…More specifically, a Gibbs free energy less than zero and its second derivative with respect to the composition larger than zero should be concurrently reached to form a miscible blend. Usually, a more negative difference of the Gibbs free energy stands for a better miscible state …”

Section: Introductionmentioning

confidence: 99%

HLD-Based Formulation Prediction for Degassed Oil with Equivalent Minimum Miscibility Pressure

Wang,

Zhao,

Guo

et al. 2024

Energy Fuels

View full text Add to dashboard Cite

show abstract

“…More specifically, the Gibbs free energy less than zero and its second derivative with respect to the composition larger than zero should be concurrently reached to form a miscible blend . Usually, a more negative difference of the Gibbs free energy stands for a better miscible state. , Nevertheless, the Gibbs free energy was only limited to qualitatively interpret the miscibility but cannot be used to quantitatively determine a specific MMP value. Hence, at a later time, another thermodynamic parameter, the solubility parameter, was employed to determine the MMP.…”

Section: Introductionmentioning

confidence: 99%

“…30 Usually, a more negative difference of the Gibbs free energy stands for a better miscible state. 30,31 Nevertheless, the Gibbs free energy was only limited to qualitatively interpret the miscibility but cannot be used to quantitatively determine a specific MMP value. Hence, at a later time, another thermodynamic parameter, the solubility parameter, was employed to determine the MMP.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Parameters for Quantitative Miscibility Interpretations from the Bulk to Nanometer Scale

Zhang

Liu

et al. 2020

Ind. Eng. Chem. Res.

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In this paper, quantitative thermodynamic parameters are quantified and applied to evaluate the oil–gas miscibility developments and to determine the minimum miscibility pressures (MMPs) from the bulk to nanometer scale. First, mathematical formulations of the Gibbs and interfacial energies and the solubility parameter in the bulk phase and nanopores are derived coupled with a modified equation of state and semianalytical correlation. Second, the calculated Gibbs and interfacial energies and solubility parameters are utilized to analyze the miscibility development, based on which specific thermodynamic MMP criteria are developed. The calculated MMPs from the new thermodynamic MMP criteria are compared with and validated by the measured MMPs of a total of 55 dead and live oil-pure and impure gas systems in the bulk phase and nanopores at different conditions. Moreover, the effects of temperature, oil and gas compositions, and pore radius on the MMP are evaluated. It is found that the miscibility interpretation may be in variation based on different thermodynamic properties even though the miscible state performs similarly in the macroscopic perspective. Three new thermodynamic MMP criteria are developed based on the first derivatives of the Gibbs energy and solubility parameter and the second derivative of the interfacial energy with respect to pressure, which are linearly regressed and extrapolated to determine the MMP with a critical linear correlation coefficient. The three thermodynamic criteria are found to be accurate and physically correct for the MMP determinations of various oil–gas systems in the bulk phase and nanopores at different conditions, wherein the solubility parameter and interfacial energy criteria are slightly better than the Gibbs energy criterion. Overall, the miscibility is strongly dependent on the temperature, oil and gas compositions, and pore radius.

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Optimized critical parameters for n-alkanes up to C100 for reliable multiphase behavior of hydrocarbon mixture using SRK EOS

Kundu

Kumar

2021

Fluid Phase Equilibria

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Thermodynamically consistent criteria for developing reliable equation of state model for compositional simulation

Cited by 5 publications

References 73 publications

HLD-Based Formulation Prediction for Degassed Oil with Equivalent Minimum Miscibility Pressure

HLD-Based Formulation Prediction for Degassed Oil with Equivalent Minimum Miscibility Pressure

Thermodynamic Parameters for Quantitative Miscibility Interpretations from the Bulk to Nanometer Scale

Optimized critical parameters for n-alkanes up to C100 for reliable multiphase behavior of hydrocarbon mixture using SRK EOS

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