A new capillary pressure model for fractal porous media using percolation theory

Zheng, Jun; Liu, Hongbo; Wang, Keke; You, Zhenjiang

doi:10.1016/j.jngse.2017.02.033

Cited by 33 publications

(19 citation statements)

References 34 publications

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“…Similarly, for the purpose of developing an analytical relative permeability model for gas hydrate per the Purcell's approach, a capillary pressure equation that can be integrated is required. Many studies have proposed different methods to predict capillary pressure, including analytical [25][26][27][28] and numerical methods 29 , but the choice of a capillary function used in this study is based on two requirements, which are: (i) it can be integrated analytically, and (ii) it is applicable to a porous medium. Based on these two conditions, a general capillary pressure model reported by Li 25 is used as an expression to derive the proposed relative permeability model for gas hydrate-bearing sediments.…”

Section: Approachmentioning

confidence: 99%

A Novel Relative Permeability Model for Gas and Water Flow in Hydrate-Bearing Sediments With Laboratory and Field-Scale Application

Singh

Myshakin

Seol

2020

Sci Rep

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In a producing gas hydrate reservoir the effective porosity available for fluid flow constantly changes with dissociation of gas hydrate. Therefore, accurate prediction of relative permeability using legacy models (e.g. Brooks-Corey (B-C), van Genuchten, etc.) that were developed for conventional oil and gas reservoirs would require empirical parameters to be calibrated at various Sh over its range of variation, but such calibrations are precluded because of lack of experimental relative permeability data. This study proposes a new relative permeability model for gas hydrate-bearing media that is a function of maximum capillary pressure, capillary entry pressure, pore size distribution index, residual saturations, hydrate saturation, and four other constants. The three novel features of the proposed model are: (i) requires fitting its six empirical parameters only once using experimental data from any single Sh, and the same set of empirical parameters predict relative permeability at all Sh, (ii) includes the effect of capillarity, and (iii) includes the effect of pore-size distribution. From practical standpoint, the model can be used to simulate multiphase flow in gas hydrate-bearing sediments where the proposed relative permeability can account for the evolving hydrate saturation. The proposed model is implemented in a numerical simulator and the wall time required to perform simulations using the proposed model is shown to be similar to the time it takes to run same simulations with the B-C model. The proposed model is a step forward towards achieving the goal of physically accurate modeling of multiphase flow for gas hydrate-bearing sediments that accounts for the effect of gas hydrate saturation change on relative permeability.

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Section: Approachmentioning

confidence: 99%

A Novel Relative Permeability Model for Gas and Water Flow in Hydrate-Bearing Sediments With Laboratory and Field-Scale Application

Singh

Myshakin

Seol

2020

Sci Rep

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“…Substituting eq into eq , the relationship between the capillary pressure P c and saturation S h is expressed as where S h (%) is the pore volume with the capillary pressure greater than P c , P cmin (Mpa) is the displacement pressure, and D h is the fractal dimension of the pore throat size determined by the capillary pressure curve.…”

Section: Fractal Characteristics Of Nmr T2 Spectrum and Capillary Pre...mentioning

confidence: 99%

“…Substituting eq 2 into eq 1, the relationship between the capillary pressure P c and saturation S h is expressed as 25…”

Section: Fractal Characteristics Of Nmr Tmentioning

confidence: 99%

“…The pore throat size distribution obtained by NMR and MICP has fractal features. − A large number of studies have searched for the relation between pore structure characteristics and fractal characteristics of the capillary pressure curve, NMR T 2 spectrum, and relative permeability curve. − However, studies of the conversion relationship between the capillary pressure curve and NMR T 2 spectrum have not been reported by the fractal characteristic. Hence, it is necessary to study the fractal characteristic of the relation between the capillary pressure curve and NMR T 2 spectrum.…”

Section: Introductionmentioning

confidence: 99%

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Variable Dimension Fractal-Based Conversion Method between the Nuclear Magnetic Resonance T₂ Spectrum and Capillary Pressure Curve

Xie

Yin²,

Wang

et al. 2020

Energy Fuels

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Pore structure is the primary control factor of pore fluid distribution and flow capacity. It is an important content in reservoir evaluation. The capillary pressure curve is a major method to obtaining pore structure characteristics. The NMR T2 spectrum reflects pore size distribution. Both of them have a connection. Investigating methods of converting the NMR T2 spectrum into a capillary pressure curve is the key step to use nuclear magnetic resonance (NMR) logging data to quantitatively characterize the pore structure. The pore throat size distribution obtained by the NMR T2 spectrum and capillary pressure curve has fractal features. However, studies about the relationship between the capillary pressure curve and NMR T2 spectrum by the fractal characteristic have not been reported. This paper studies the relationship between the capillary pressure curve and NMR T2 spectrum by the fractal characteristic and proposes a method of converting the NMR T2 spectrum to the capillary pressure curve. To fully consider the influence of the pore structure, the dimension coefficient is set to be a variable that is related to the pore structure. The proposed model is verified by 20 rock samples in Nanpu sag, China by comparing the new method of calculate capillary pressure curves and experimental capillary pressure curves. Results show that the new method improves the accuracy of the conversion method between the NMR T2 spectrum and capillary pressure curve in the complex pore structure reservoirs. This research provides a new way to enrich pore structure characteristic parameters for high-precision reservoir evaluation and has certain guidance and reference significance for the research work of petrophysics, reservoir evaluation, and NMR logging data application.

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“…is the ratio of the porous volume, occupied by the liquid, without the effect of the surrounding sites; • is the ratio of the porous volume, occupied by liquid, accounting for the effect of the surrounding sites. Additionally, and are also known to be the fractions of "allowed" pores and "accessible" pores at each site, respectively (Zheng et al, 2017). Thus, it can be assumed that the fraction of "accessible" pores represents the local saturation.…”

mentioning

confidence: 99%

Self-organized gradient percolation method for numerical simulation of impregnation in porous media

Nguyen

Blond

Sayet

et al. 2019

Computer Methods in Applied Mechanics and Engineering

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A new capillary pressure model for fractal porous media using percolation theory

Cited by 33 publications

References 34 publications

A Novel Relative Permeability Model for Gas and Water Flow in Hydrate-Bearing Sediments With Laboratory and Field-Scale Application

A Novel Relative Permeability Model for Gas and Water Flow in Hydrate-Bearing Sediments With Laboratory and Field-Scale Application

Variable Dimension Fractal-Based Conversion Method between the Nuclear Magnetic Resonance T₂ Spectrum and Capillary Pressure Curve

Self-organized gradient percolation method for numerical simulation of impregnation in porous media

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A new capillary pressure model for fractal porous media using percolation theory

Cited by 33 publications

References 34 publications

A Novel Relative Permeability Model for Gas and Water Flow in Hydrate-Bearing Sediments With Laboratory and Field-Scale Application

A Novel Relative Permeability Model for Gas and Water Flow in Hydrate-Bearing Sediments With Laboratory and Field-Scale Application

Variable Dimension Fractal-Based Conversion Method between the Nuclear Magnetic Resonance T2 Spectrum and Capillary Pressure Curve

Self-organized gradient percolation method for numerical simulation of impregnation in porous media

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Variable Dimension Fractal-Based Conversion Method between the Nuclear Magnetic Resonance T₂ Spectrum and Capillary Pressure Curve