A method for obtaining the tortuosity and permeability of a porous medium based on a rectangular particle model

Abstract

The present invention discloses a method for obtaining the tortuosity and permeability of a porous medium based on a rectangular particle model. For rectangular porous medium particles, a microscopic structure model is established by a fractal method, which can be used to obtain the tortuosity, permeability and capillary entry pressure of a porous medium composed of rectangular particles with different shape parameters. By establishing a microscopic structure model of a porous medium composed of rectangular particles, this method realizes the quantification of the water flow movement parameters of the porous medium, is suitable for simulating and predicting the migration of chlorinated hydrocarbon pollutants in an aquifer, and can realize the identification of the particle shape parameters of the aquifer, and has wide applicability to the accurate simulation of groundwater flow movement and pollutant migration and remediation.

Description

Technical Field

[0001] The present invention belongs to the technical field of pollutant migration, and more specifically, relates to a method for obtaining the tortuosity and permeability of a porous medium based on a rectangular particle model. Background Art

[0002] Groundwater is an important part of water resources, and more than 50% of the world's population uses groundwater as a domestic drinking water source. Hydrodynamic conduction parameters of porous media such as permeability and capillary entry pressure not only affect the migration of pollutants in aquifers, but also play an important role in pollutant remediation.

[0003] Most of the microstructure models in previous studies were too idealized, only considering simple geometric shapes of particles such as squares, while the geometric shapes of porous media in natural aquifers are often more complex. Currently, there is a lack of research on the property parameters of porous media composed of particles with different shape parameters, and the influence of the shape parameters of medium particles on the migration and bioremediation of pollutants such as chlorinated hydrocarbons in macroscopic aquifers cannot be quantified. Summary of the Invention

[0004] Aiming at the above existing technical problems, the purpose of the present invention is to provide a method for obtaining the tortuosity and permeability of a porous medium based on a rectangular particle model. This method establishes a microscopic model for rectangular particles with different shape parameters, and can quantitatively calculate the macroscopic tortuosity, permeability coefficient, and capillary entry pressure of a porous medium composed of rectangular particles with different shape parameters, and has strong applicability in determining the shape parameters of aquifer porous medium particles, numerical simulation prediction of the migration and remediation of chlorinated hydrocarbon pollution tasks in aquifers.

[0005] In order to achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] A method for obtaining the tortuosity and permeability of a porous medium based on a rectangular particle model, comprising the following steps:

[0007] S1. Establish a microscopic model of a porous medium composed of rectangular particles, measure the shape parameter data of the rectangular particles, and process the shape parameter data to obtain the average diameter of the pores of the porous medium;

[0008] S2. Obtain the tortuosity of the porous medium according to the average diameter of the pores of the porous medium in S1;

[0009] S3. Obtain the permeability and capillary entry pressure of the porous medium.

[0010] The present invention provides a method for obtaining the tortuosity and permeability of a porous medium based on a rectangular particle model. By establishing a microscopic model of a porous medium composed of rectangular particles, first, the average pore diameter of a porous medium composed of rectangular particles with different shape parameters is deduced, then a tortuosity model of the rectangular particle porous medium is established, and finally, the permeability and capillary entry pressure of the porous medium are obtained based on the average pore diameter and tortuosity. This method can quantitatively calculate the macroscopic tortuosity, permeability, capillary entry pressure, etc. of a porous medium, and has strong applicability in the determination of the particle shape parameters of an aquifer porous medium and the numerical simulation prediction of the migration and remediation of chlorinated hydrocarbon pollution tasks in the aquifer.

[0011] Preferably, the microscopic model of the porous medium includes a triangular arrangement model and a square arrangement model; in the triangular arrangement model, the rectangular particles are arranged in the form of an equilateral triangle; in the square arrangement model, the rectangular particles are arranged in the form of a square.

[0012] Preferably, the square arrangement model is composed of 9 rectangular particles, and the rectangular particle at the center of the square arrangement model forms a representative unit cell with a unit thickness; the data for measuring the shape parameters of the rectangular particles includes measuring the ratio μ of the width to the length of the rectangular particle, measuring the length 2R of the rectangular particle, measuring the width 2μR of the rectangular particle, and measuring the gap size d between the rectangular particles.

[0013] Preferably, the porosity of the unit cell is:

[0014]

[0015]

[0016] wherein, the porosity of the unit cell is θ; P rp is the ratio of d to R; A trp is the total volume of the unit cell,

[0017] A prp is the pore volume of the unit cell;

[0018] Preferably, the average diameter of the pores of the porous medium is:

[0019]

[0020] wherein, λ RP is the average diameter of the pores in the unit cell; λ max,RP is the maximum diameter of the pores in the unit cell, A aprp is the pore volume in the triangular model:

[0021]

[0022] Preferably, the tortuosity of the porous medium is:

[0023] First, calculate the flow path of the porous medium;

[0024] Flow path l AB +l BC +l CD The tortuosity of is:

[0025]

[0026] where the curved flow path of the streamline is l AB +l BC +l CD ; the straight-line distance is l AO ;

[0027] Flow path l AC +l CD The tortuosity of is:

[0028]

[0029] Preferably, considering the overlap of the flow path and the porous medium particles, the tortuosities of the flow paths l AC and l EC are respectively:

[0030] τ′ rp2 =l AC / (l AC cosα1);

[0031] τ rp3 =l EC / (l EC cosβ1)=1 / cosβ1;

[0032] where,

[0033] Preferably, the average tortuosity of the triangular arrangement model is:

[0034]

[0035] The average tortuosity of the square arrangement model is:

[0036]

[0037] where the tortuosity of the curved flow path is The tortuosity of the straight flow path is τ″ rp4 =1; P rp2is the ratio of d to R in the square arrangement model, The porosity in the square arrangement model is θ = A′ prp / A′ trp = 1 - 4μ[2μ + d / R] -2 ; A′ trp = l T ·(2μR + d) 2 is the total volume of the square arrangement model; A′ prp = l T ·[(2μR + d) 2 - 4μR 2 is the pore volume in the square arrangement model;

[0038] The tortuosity of the porous medium is:

[0039] Preferably, the permeability of the porous medium is:

[0040]

[0041] where k is the permeability of the porous medium; D f is the fractal dimension of the pore area of the porous medium, ; D T is the fractal dimension of the tortuosity of the porous medium, ; d + = 2R / 2R min = R / R min , R min is the minimum radius of the porous medium; L S is the straight-line length of the flow path of the porous medium; A c is the cross-sectional area of the flow path of the porous medium; λ max is the maximum diameter of the capillary.

[0042] Preferably, the capillary entry pressure of the porous medium is:

[0043] where the capillary entry pressure of the porous medium is Pc; λ av is the average diameter of the pores; ω = Fσcosα; F is the shape coefficient determined by the capillary and the fluid flow direction; α is the contact angle of the solid-liquid interface; σ is the surface tension of the wetting fluid.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention provides a method for calculating the tortuosity and permeability of porous media based on a rectangular particle model. By establishing a microscopic model of a porous medium composed of rectangular particles, first, the average pore diameter of a porous medium composed of rectangular particles with different shape parameters is deduced, then a tortuosity model of the rectangular particle porous medium is established, and finally, the permeability and capillary entry pressure of the porous medium are obtained based on the average pore diameter and tortuosity. This method establishes a microscopic model for rectangular particles with different shape parameters, and can quantitatively calculate the macroscopic tortuosity, permeability coefficient, and capillary entry pressure of a porous medium composed of rectangular particles with different shape parameters, and has strong applicability in determining the particle shape parameters of an aquifer porous medium and numerical simulation prediction of the migration and remediation of chlorinated hydrocarbon pollution tasks in the aquifer. Description of the Drawings

[0046] Figure 1 It is a porous medium model composed of rectangular particles with different shape parameters; among them, Figure 1 (a) is a triangular arrangement model; Figure 1 (b) is a square arrangement model.

[0047] Figure 2 It is a schematic diagram of a three-dimensional aquifer; among them, Figure 2 (a) is a three-dimensional schematic diagram of a three-dimensional aquifer; Figure 2 (b) is the position of all injection wells, extraction wells, and monitoring wells in the X-Y plane of the three-dimensional aquifer; Figure 2 (c) is the depth of all wells in the three-dimensional aquifer; Figure 2 (d) is the three-dimensional distribution of the porosity of the three-dimensional aquifer; Figure 2 (e) is the initial saturation distribution of TCE in the three-dimensional aquifer.

[0048] Figure 3 It is the spatial distribution of the permeability and capillary entry pressure of a three-dimensional aquifer obtained based on the rectangular particle porous medium model; among them, Figure 3 (a) is the spatial distribution of the permeability of the aquifer calculated based on the rectangular particle porous medium model; Figure 3 (b) is the spatial distribution of the capillary entry pressure of the aquifer calculated based on the rectangular particle porous medium model.

[0049] Figure 4 It is the average value and standard deviation of the permeability and capillary entry pressure of a three-dimensional aquifer obtained based on the rectangular particle porous medium model; among them, Figure 4 (a) is the average value and standard deviation of the permeability of the aquifer calculated based on the rectangular particle porous medium model; Figure 4 (b) is the average value and standard deviation of the capillary entry pressure calculated based on the rectangular particle porous medium model.

[0050] Figure 5 The residual saturation of TCE and the concentration of methanotrophic bacteria in the repaired aquifer obtained from the simulation of TCE migration and biodegradation based on the rectangular particle porous medium model; among them, Figure 5 (a) is the comparison between the residual saturation distribution of TCE in the repaired aquifer obtained from the simulation of TCE migration and biodegradation based on the rectangular particle porous medium model and the actual result; Figure 5 (b) is the comparison between the concentration of methanotrophic bacteria in the repaired aquifer obtained from the simulation of TCE migration and biodegradation based on the rectangular particle porous medium model and the actual result.

[0051] Figure 6 The remaining TCE volume and the remediation efficiency obtained from the simulation of TCE migration and biodegradation based on the rectangular particle porous medium model.

[0052] Figure 7 The simulation results of TCE migration and biodegradation based on the rectangular particle porous medium model; among them, Figure 7 (a) is the remaining TCE volume in the aquifer; Figure 7 (b) is the GTP parameter value of the TCE plume; Figure 7 (c) is the mass of methanotrophic bacteria; Figure 7 (d) is the number of heterotrophic organisms in the aquifer during the whole process.

[0053] Figure 8 The moment analysis results of the TCE plume obtained from the simulation of TCE migration and biodegradation based on the rectangular particle porous medium model; among them, Figure 8 (a) is the first moment of the TCE plume along the X, Y, and Z directions; Figure 8 (b) is the second moment of the TCE plume along the X, Y, and Z directions. Detailed implementation manners

[0054] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments, but the embodiments do not impose any form of limitation on the present invention. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

[0055] In addition, unless otherwise specified, the reagents and materials used in the following embodiments are all commercially available.

[0056] Embodiment 1

[0057] (1) The permeability and capillary entry pressure of the three-dimensional aquifer were deduced based on the rectangular particle porous medium model. The specific deduction method is as follows:

[0058] As Figure 1 shown, among which Figure 1 (a) is the triangular arrangement model,Figure 1 (b) is the square arrangement model. The microscopic models of the porous medium include the triangular arrangement model and the square arrangement model; the triangular arrangement model uses rectangular particles arranged in the form of an equilateral triangle; the square arrangement model uses rectangular particles arranged in the form of a square.

[0059] Among them, the square arrangement model consists of 9 rectangular particles, and the rectangular particle at the center of the square arrangement model forms a representative unit cell with a unit thickness; the measured shape parameter data of the rectangular particles include the ratio μ of the width to the length of the rectangular particle, the length 2R of the rectangular particle, the width 2μR of the rectangular particle, and the gap size d between the rectangular particles.

[0060] Among them, the porosity of the unit cell is:

[0061]

[0062]

[0063] Among them, the porosity of the unit cell is θ; P rp is the ratio of d to R; A trp is the total volume of the unit cell,

[0064] A prp is the pore volume of the unit cell;

[0065] Among them, the average diameter of the pores of the porous medium is:

[0066]

[0067] Among them, λ RP is the average diameter of the pores in the unit cell; λ max,RP is the maximum diameter of the pores in the unit cell, A aprp is the pore volume in the triangular model:

[0068]

[0069] Among them, the tortuosity of the porous medium is:

[0070] First, calculate the flow path of the porous medium;

[0071] The tortuosity of the flow path l AB +l BC +l CD is:

[0072]

[0073] Among them, the curved flow path of the streamline is l AB +l BC +l CD ; The straight-line distance is l AO ;

[0074] The flow path l AC +l CD The tortuosity of is:

[0075]

[0076] Among them, considering the overlap of the flow path and the porous medium particles, the tortuosities of the flow paths l AC and l EC are respectively:

[0077] τ′ rp2 =l AC / (l AC cosα1);

[0078] τ rp3 =l EC / (l EC cosβ1)=1 / cosβ1;

[0079] Among them,

[0080] Among them, the average tortuosity of the triangular arrangement model is:

[0081]

[0082] Among them, the average tortuosity of the square arrangement model is:

[0083]

[0084] Among them, the tortuosity of the curved flow path is The tortuosity of the straight flow path is τ″ rp4 =1; P rp2 is the ratio of d and R in the square arrangement model, The porosity in the square arrangement model is θ = A′ prp / A′ trp =1 - 4μ[2μ + d / R] -2 ; A′ trp =l T ·(2μR + d) 2 is the total volume of the square arrangement model; A′ prp =l T ·[(2μR + d) 2 -4μR 2 is the pore volume in the square arrangement model;

[0085] Among them, the tortuosity of the porous medium is:

[0086] Among them, the permeability of the porous medium is:

[0087]

[0088] Among them, k is the permeability of the porous medium; D f is the fractal dimension of the pore area of the porous medium, ; D T is the fractal dimension of the tortuosity of the porous medium, d + = 2R / 2R min = R / R min R min is the minimum radius of the porous medium; L S is the straight-line length of the flow path of the porous medium; A c is the cross-sectional area of the flow path of the porous medium; λ max is the maximum diameter of the capillary.

[0089] Among them, the capillary entry pressure of the porous medium is:

[0090] Among them, the capillary entry pressure of the porous medium is Pc; λ av is the average diameter of the pores; ω = Fσcosα; F is the shape factor determined by the capillary and the fluid flow direction; α is the contact angle of the solid-liquid interface; σ is the surface tension of the wetting fluid.

[0091] (2) As Figure 2 (a) shows, a three-dimensional aquifer is selected. This aquifer is a three-dimensional heterogeneous aquifer composed of sand, gravel and clay. The horizontal area of this aquifer is 54 × 20 m 2 , the groundwater depth is 5.9 m, and the groundwater flow direction is northeast. Chlorinated hydrocarbon pollutants are discharged into this aquifer, and trichloroethylene (TCE) is the main component of the chlorinated hydrocarbons. As Figure 2 (b) shows, the three-dimensional aquifer is divided into 6 × 20 × 17 grids.

[0092] After the chlorinated hydrocarbon pollutants are discharged into the aquifer, they begin to migrate in the aquifer and reach the bottom of the aquifer through the vadose zone. During the vertical infiltration of TCE, a part of the chlorinated hydrocarbon pollutants remains in the porous medium, forming a residual pollution pool. These residual chlorinated hydrocarbon pollutants with low solubility can become persistent pollution sources in the aquifer.

[0093] As Figure 2 (b) and Figure 2As shown in (c), 11 wells are arranged in the three-dimensional aquifer: 3 pumping wells (W1 - 3), 4 injection wells (W4 - 6 and W8), and 4 monitoring wells (W7 and W9 - 11). The porosity of the three-dimensional aquifer is as Figure 2 shown in (d). It can be seen from the figure that both sides and the bottom of the aquifer are porous media with relatively low porosity and permeability. The groundwater flows from right to left with a hydraulic gradient of 0.002. The chlorinated hydrocarbon pollutants are almost entirely composed of TCE. Therefore, it is assumed that the chlorinated hydrocarbon is 100% TCE in the migration and bioremediation models of chlorinated hydrocarbon pollutants. The initial saturation of TCE in the three-dimensional aquifer is as Figure 2 shown in (e). The diffusion coefficient is 7.34×10 -5 m 2 / d, the longitudinal dispersivity is 3.05×10 -3 m, and the transverse dispersivity is 0 m.

[0094] The bioremediation process of TCE includes two stages: surfactant-enhanced aquifer remediation (SEAR) and bioremediation. The surfactant-enhanced aquifer remediation is implemented within 0 - 227 days and includes 5 steps: (1) Natural migration of TCE (0 - 97 days); (2) Conducting a tracer test (97 - 115 days) to estimate the residual TCE saturation in this three-dimensional aquifer, including initial water injection flushing, tracer injection, water washing, surfactant injection (Well W5), water washing, and extraction; (3) Injecting a surfactant solution (anionic surfactant - sodium dihexyl sulfosuccinate) into the three-dimensional aquifer to enhance the solubility and mobility of TCE, including tracer injection, sodium chloride solution injection, surfactant injection, tracer test, and final extraction (115 - 208 days); (4) Injecting water (Well W8) to flush the aquifer; (5) Conducting a flushing tracer test to estimate the residual TCE saturation.

[0095] To further reduce the content of trichloroethylene in the three-dimensional aquifer, pollutant bioremediation was carried out after the surfactant-enhanced aquifer remediation, including high-flow pumping (the injection flow rate of the three injection wells is 13.6 m 3 / d) and a low-speed pumping stage (the injection rate is reduced to 1.36 m 3 / d). In this stage, methane-oxidizing bacteria, methane, and oxygen at concentrations of 10 mg / L, 20 mg / L, and 300 mg / L were injected into the aquifer through injection wells W4, W5, and W6 respectively. At the same time, groundwater containing TCE pollutants was pumped out through the three wells W1, W2, and W3.

[0096] During the biodegradation remediation process, the biodegradation reaction between methane and trichloroethylene is:

[0097]

[0098] Methanotrophs obtain energy from methane oxidation. Methane monooxygenase (MMO) oxidizes methane to methanol, and finally produces carbon dioxide, water and biomass. During the biodegradation of methane, NAD(P)H is used to store reducing energy to build more cell substances. The biodegradation equation of TCE is a suicide process of methanotrophs. The toxic intermediates produced by MMO oxidizing TCE are harmful to methanotrophs. When 1 mg of TCE is oxidized by MMO, 10 mg of methanotrophs are killed.

[0099] Among them, the spatial distributions of the corresponding permeability and capillary entry pressure are as Figure 3 (a) and Figure 3 (b) shown. Subsequently, the migration and bioremediation processes of TCE are simulated by UTCHEM. Most of the porous media at the top of the aquifer are of low permeability, while only a small part of the porous media at the bottom has good permeability. Most of the porous media at the bottom of the aquifer are also of low permeability. The low-permeability porous media are distributed along the water flow direction and at the bottom of the aquifer.

[0100] Among them, Figure 4 (a) and Figure 4 (b) are the mean values and standard deviations of the permeability and capillary entry pressure in the three-dimensional aquifer calculated based on the rectangular particle porous media model. For the rectangular particle porous media model, the results show that both the mean value and standard deviation of the permeability decrease with the increase of μ (the ratio of the width to the length of the rectangular particle). The mean value of the capillary entry pressure increases with the increase of μ, reaches the maximum when μ is 0.7, and then decreases when μ continues to increase.

[0101] The distributions of the residual TCE and methanogenic bacteria in the aquifer after the SEAR and bioremediation processes simulated by UTCHEM are as Figure 5 (a) and Figure 5 (b) shown. The simulation results of TCE migration and remediation based on the rectangular particle porous media model show that there is no residual TCE in the aquifer finally. When μ decreases, after the SEAR and bioremediation processes, the TCE saturation in the aquifer is still very high, and the remaining amounts of TCE and methanotrophs are both higher than the actual results. The remaining TCE saturation obtained from the simulation results decreases with the increase of μ, indicating that the bioremediation effect increases with the increase of μ. When the value of μ is large, SEAR and bioremediation have a good removal effect on TCE in the aquifer. Most of the TCE is biodegraded after the remediation, and the methanogen population remains at a low level. As Figure 5 and as Figure 6 shown, the simulation results show that the shape parameter μ of the rectangular particles has a significant effect on the residual amount of TCE in the aquifer. With the increase of μ, the remediation efficiency also gradually increases.

[0102] The residual TCE in the aquifer after bioremediation is as follows Figure 7 (a) shows. During the period from 0 to 97 days, TCE undergoes natural migration during this period, and the total volume of residual TCE in the aquifer remains basically unchanged. After t = 97 days, the first SEAR is carried out to remove TCE, and there is a decrease in the total volume of TCE as shown in Figure 7 (a). During this period, the geometric shape parameters of the rectangular particles affect the remediation effect of the aquifer and the corresponding residual amount of TCE to varying degrees. After the first SEAR, a larger-scale SEAR remediation test was carried out. During the second SEAR remediation process from 115 to 207 days, a large amount of TCE in the aquifer was removed. However, after the SEAR remediation is completed, there is still a small amount of TCE remaining in the aquifer. Therefore, a bioremediation test was carried out on the aquifer at t = 208 days.

[0103] As shown in Figure 7 (b), during the entire period from 0 to 627 days, based on the simulation results of TCE migration and remediation of the rectangular particle porous media model with different geometric shape parameters, the GTP (the ratio of the total amount of discrete and pool-shaped pollutants) of the TCE pollution plume is obtained. During the entire remediation process, the proportion of pool-shaped TCE gradually decreases, and the value of GTP gradually increases as the remediation process progresses. The peak value of GTP appears at t = 207 days, reflecting that most of the aquifer has been cleared and the TCE pollution pool has almost completely disappeared. The change in the GTP value from t = 208 to 627 days shows that only the simulation results of the rectangular particle porous media models based on RP (μ = 0.1), RP (μ = 0.3), and RP (μ = 0.5) show that there is still a small amount of TCE remaining in the aquifer after the remediation is completed. The changes of methanogens and heterotrophic bacteria from 0 to 627 days are as shown in Figure 7 (c) and Figure 7 (d). The mass of methanogens remains at a low level before t = 227 days. After t = 227 days, methanotrophic bacteria are injected into the aquifer, as shown in Figure 7 (c). As TCE is gradually biodegraded, the activity of heterotrophic bacteria increases. Heterotrophs biodegrade isopropanol and surfactants during the bioremediation process. The mass of heterotrophic bacteria shows a peak after t = 227 days, as shown in Figure 7 (d). The higher the microbial concentration, the more residual TCE there is in the aquifer and the weaker the biodegradation effect.

[0104] Figure 8 (a) and Figure 8(b) are the first and second moments of the TCE plume obtained from the simulation results of TCE migration and remediation based on the rectangular particle porous media model. The values of all the first and second moments changed significantly around t = 207 days, corresponding to the second SEAR remediation process in the figure. The differences in the first and second moments of the TCE plume obtained from the simulation results of TCE migration and remediation based on the rectangular particle porous media model with different geometric shape parameters indicate that the geometric shape parameters of the porous media particles have an important impact on the migration and redistribution during the TCE bioremediation process. From t = 0 to 207 days, the first moments of the TCE plume simulated by the rectangular particle porous media model with all geometric shape parameters along the X, Y, and Z directions are similar, but the values are different during the bioremediation period, as shown in Figure 8 (a). In addition, from t = 0 to 207 days, the second moments of TCE along the X and Y directions obtained from the simulation results are slightly different, while the second moment along the Z direction has obvious differences during the same period, as shown in Figure 8 (b). In addition, according to the comparison with the actual results, the rectangular particle porous media model with μ = 0.9 has the best simulation effect on the migration and remediation process of TCE in the three-dimensional aquifer, indicating that the shape of the porous media particles in the actual aquifer is closest to the rectangular particles with μ = 0.9.

[0105] The foregoing examples are merely illustrative and are used to explain some features of the method described in the present invention. The appended claims are intended to claim the broadest scope conceivable, and the embodiments presented herein are supported by the applicant's actual test results. Therefore, the applicant's intention is that the appended claims not be limited by the selection of examples that illustrate the features of the present invention. Some of the numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should also be construed as being covered by the appended claims where possible.

Claims

1. A method for obtaining the tortuosity and permeability of a porous medium based on a rectangular particle model, characterized in that, It includes the following steps: S1. Establish a microscopic model of a porous medium composed of rectangular particles, measure the shape parameter data of the rectangular particles, and process the shape parameter data to obtain the average diameter of the pores of the porous medium; S2. Obtain the tortuosity of the porous medium according to the average diameter of the pores of the porous medium in S1; S3. Obtain the permeability and capillary entry pressure of the porous medium; The microscopic model of the porous medium includes a triangular arrangement model and a square arrangement model; the triangular arrangement model arranges rectangular particles in the form of an equilateral triangle; the square arrangement model arranges rectangular particles in the form of a square; The square arrangement model is composed of 9 rectangular particles, and the rectangular particle at the center of the square arrangement model forms a representative unit cell with a unit thickness; the measurement of the shape parameter data of the rectangular particles includes measuring the ratio μ of the width to the length of the rectangular particles, measuring the length 2R of the rectangular particles, measuring the width 2μR of the rectangular particles, and measuring the gap size d between the rectangular particles; The porosity of the unit cell is: wherein, the porosity of the cell is θ; P rp is the ratio of d and R; A trp is the total volume of the cell, A prp is the pore volume of the cell; 2. The method according to claim 1, wherein The average diameter of the pores of the porous medium is: Among them, λ RP is the average diameter of the pores in the unit cell; λ max,RP is the maximum diameter of the pores in the unit cell, A aprp is the pore volume in the triangular model:

3. The method according to claim 1, wherein The tortuosity of the porous medium is: First, calculate the flow path of the porous medium; Flow path l AB +l BC +l CD The tortuosity of: Among them, the curved flow path of the streamline is l AB +l BC +l CD ; the straight-line distance is l AO ; Flow path l AC +l CD The tortuosity of:

4. The method according to claim 3, wherein Considering the overlap of the flow path and the porous medium particles, the flow paths l AC and l EC have tortuosities of respectively: τ′ rp2 = l AC / (l AC cos α1); τ rp3 = l EC / (l EC cosβ1) = 1 / cosβ1; Among them, 5. According to the method described in claim 4, characterized in that The average tortuosity of the triangular arrangement model is: The average tortuosity of the square arrangement model is: Among them, the tortuosity of the curved flow path is The tortuosity of the straight flow path is τ″ rp4 = 1; P rp2 is the ratio of d and R in the square arrangement model, The porosity in the square arrangement model is θ = A′ prp / A′ trp = 1 - 4μ[2μ + d / R] -2 ; A′ trp = l T ·(2μR + d) 2 is the total volume of the square arrangement model; A′ prp = l T ·[(2μR + d) 2 - 4μR 2 is the pore volume in the square arrangement model; The tortuosity of the porous medium is as follows:

6. The method according to claim 1, characterized in that, The permeability of the porous medium is: where k is the permeability of the porous medium; D f is the fractal dimension of the pore area of the porous medium, D T is the fractal dimension of the tortuosity of the porous medium, d + = 2R / 2R min = R / R min where R min is the minimum radius of the porous medium; L S is the straight-line length of the flow path of the porous medium; A c is the cross-sectional area of the flow path of the porous medium; λ max is the maximum diameter of the capillary tube.

7. The method according to claim 6, wherein The capillary entry pressure of the porous medium is as follows: wherein, the capillary entry pressure of the porous medium is Pc; λ av is the average diameter of the pores; ω = Fσcosα; F is the shape factor determined by the capillary and the fluid flow direction; α is the contact angle of the solid-liquid interface; σ is the surface tension of the wetting fluid.

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