Rock permeability calculation method based on digital core technology

Abstract

The invention relates to a rock permeability calculation method and device, belongs to the technical field of geographic information, and particularly relates to a rock permeability calculation method based on a digital core technology. The method and the device are based on a digital core technology, the permeability of reservoir rock is calculated by utilizing a numerical simulation means, and the influence of pore structure change on the permeability of the rock is further analyzed by changing pore throat parameters in multiples, establishing a new pore network model and calculating the permeability of the new model. The problem of quantitative change of the digital core pore structure and the problem of difficulty in calculating and analyzing the change permeability parameter of the pore structure are solved.

Description

Technical Field

[0001] The invention relates to a rock permeability calculation method, belonging to the field of geographic information technology, and specifically to a rock permeability calculation method based on digital core technology. Background Art

[0002] Permeability is a parameter that characterizes the flow characteristics of fluids in rock pores and is an effective parameter for evaluating the ease of fluid flow. Rock permeability is controlled by the microscopic pore structure of the rock. Obtaining rock permeability parameters is of great significance for evaluating reservoir properties. Rock permeability research plays an important role in research fields such as oil and gas reservoir exploration and development, hydrogeology, geotechnical engineering, and rock physics.

[0003] Digital core technology is based on the micro-nanoscale imaging of rocks and the digitization of core data. It conducts numerical simulation research on physical properties such as rock elasticity, permeability, and electrical properties, establishes the relationship between rock physical properties and reservoir physical properties, and lays the foundation for reservoir physical property evaluation. The purpose of digital rock physics modeling is to establish a digital form of rock, obtain the characteristics of rock pore space, and provide a model basis for rock permeability calculation. The modeling methods of digital cores include two categories: physical experimental scanning method and numerical simulation reconstruction method. Micro-nano CT scanning method is one of the physical experimental scanning methods. It can characterize the pore space characteristics of rocks from the pore scale and reflect the characteristics of real rocks.

[0004] In the study of reservoir permeability, it is crucial to understand the factors that control the flow of reservoir fluids. One influencing factor that needs to be considered is the arrangement characteristics of the pore space. This information can be obtained by constructing a three-dimensional digital core through micro-nano CT scanning. With the continuous improvement of the accuracy of the scanning equipment, the pore space information becomes more reliable, and the scanning resolution can reach μm or even nm. Numerical simulation of rock physical properties based on digital cores can explore the changing laws of physical properties from a microscopic scale, quantify the relationship between permeability and pore structure, establish the connection between microscopic and macroscopic parameters, and provide data support for the construction of rock physical models and the prediction and interpretation of reservoir geophysical properties.

[0005] Regarding the calculation of rock permeability, the traditional method is mainly based on theoretical formulas. A permeability model is established through parameters such as lithology type, porosity, and particle size to calculate the rock permeability parameters. This method is greatly affected by the region and lithology. There is a large error between the calculated permeability and the actual reservoir permeability, and this method cannot analyze the relationship between permeability and pore structure from a microscopic pore scale.

[0006] Because some reservoir rocks are extremely dense and cannot be tested with rock physics experiments, permeability parameters cannot be obtained. Rock permeability is affected by microscopic pore structure, and traditional rock physics experiments cannot calculate the relationship between pore structure and permeability. The calculation of rock permeability based on digital core technology still faces the problem that the pore structure characteristics of digital cores are difficult to change quantitatively, and thus it is impossible to effectively calculate the influence of pore structure changes on permeability. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a rock permeability calculation method based on digital core technology. The method is based on digital core technology and uses numerical simulation to calculate the permeability of reservoir rocks. By changing the pore throat parameters exponentially, a new pore network model is established, and the permeability of the new model is calculated. The influence of pore structure changes on rock permeability is further analyzed, which solves the problem of quantitative changes in digital core pore structure and the difficulty in calculating and analyzing permeability parameters of pore structure changes.

[0008] To solve the above problems, the solution of the present invention is:

[0009] A rock permeability calculation method based on digital core technology, comprising:

[0010] A core construction step for obtaining a three-dimensional digital core representing the rock pore structure;

[0011] A model building step is used to establish a pore network model, wherein in the pore network model, the largest pore space in the digital core is represented by pores, and the channels connecting these pores are represented by throats;

[0012] The pore throat parameter extraction step is used to statistically calculate the pore throat parameters in the pore network model;

[0013] a permeability calculation step, for obtaining a variation relationship between a permeability parameter and a pore throat parameter according to the pore throat parameter;

[0014] The model reconstruction step is used to change one or more of the pore throat parameters to establish a new pore network model, and then re-execute the permeability calculation step.

[0015] Preferably, in the above-mentioned rock permeability calculation method based on digital core technology, in the network model construction step, the maximum sphere method is used to establish the digital core pore network model.

[0016] Preferably, in the above-mentioned rock permeability calculation method based on digital core technology, in the pore throat parameter extraction step, the shape factor is calculated based on the following formula:

[0017]

[0018] Where V is the volume of the pore or throat; L is the length of the pore or throat; A s Represents the surface area of ​​a pore or throat.

[0019] Preferably, in the above-mentioned rock permeability calculation method based on digital core technology, in the permeability calculation step, the permeability of the pore network model is calculated based on the following formula:

[0020]

[0021] Where K represents permeability; L represents the total length of the pore network model; A represents the area of ​​the fluid inlet and outlet of the pore network model; μ p represents the viscosity of the p-phase fluid; q p represents the flow rate of the p-phase fluid; P in -P out Indicates the pressure difference between the input and output ends.

[0022] Preferably, in the above-mentioned rock permeability calculation method based on digital core technology, in the model reconstruction step, a new pore network model is formed by quantitatively changing the parameters in the pore network model through the deformation factor based on the following formula:

[0023] f1(x)=n×f0(x)

[0024] Where x represents the radius or shape factor of the pore and throat, f0(x) represents the probability distribution of this parameter in the initial pore network model, f1(x) represents the probability distribution of this parameter in the new pore network model, and n represents the deformation factor, which is a natural number.

[0025] A rock permeability calculation device based on digital core technology, comprising:

[0026] Core construction module, used to obtain three-dimensional digital cores representing the rock pore structure;

[0027] A model building module is used to establish a pore network model, wherein in the pore network model, the largest pore space in the digital core is represented by pores, and the channels connecting these pores are represented by throats;

[0028] Pore ​​throat parameter extraction module, used to statistically calculate the pore throat parameters in the pore network model;

[0029] A permeability calculation module, used for obtaining a change relationship between a permeability parameter and a pore throat parameter according to the pore throat parameter;

[0030] The model reconstruction module is used to change one or more of the pore throat parameters to establish a new pore network model, and then re-execute the permeability calculation module.

[0031] Preferably, in the above-mentioned rock permeability calculation device based on digital core technology, in the network model construction module, the maximum sphere method is used to establish the digital core pore network model.

[0032] Preferably, in the above-mentioned rock permeability calculation device based on digital core technology, the pore throat parameter extraction module calculates the shape factor based on the following formula:

[0033]

[0034] Where V is the volume of the pore or throat; L is the length of the pore or throat; A s Represents the surface area of ​​a pore or throat.

[0035] Preferably, in the above-mentioned rock permeability calculation device based on digital core technology, the permeability calculation module calculates the permeability of the pore network model based on the following formula:

[0036]

[0037] Where K represents permeability; L represents the total length of the pore network model; A represents the area of ​​the fluid inlet and outlet of the pore network model; μ p represents the viscosity of the p-phase fluid; q p represents the flow rate of the p-phase fluid; P in -P out Indicates the pressure difference between the input and output ends.

[0038] Preferably, in the rock permeability calculation device based on digital core technology, in the model reconstruction module, a new pore network model is formed by quantitatively changing the parameters in the pore network model through the deformation factor based on the following formula:

[0039] f1(x)=n×f0(x)

[0040] Where x represents the radius or shape factor of the pore and throat, f0(x) represents the probability distribution of this parameter in the initial pore network model, f1(x) represents the probability distribution of this parameter in the new pore network model, and n represents the deformation factor, which is a natural number.

[0041] Therefore, compared with the prior art, the advantages of the present invention are: this method can construct the rock pore structure from a microscopic scale based on digital core technology, quantitatively change the size of rock pore throat parameters by multiples, obtain a large number of new pore network models, and calculate the rock permeability by numerical simulation, saving a lot of manpower and material resources, and can obtain the permeability parameters of rocks more conveniently and quickly, and more effectively explore the relationship between pore structure changes and permeability. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable one skilled in the art to make and use the present disclosure.

[0043] Figure 1 This is a flow chart of a rock permeability calculation method based on digital core technology.

[0044] Figure 2 Schematic diagram of the process of establishing pore and throat links in the pore network model.

[0045] Figure 3 This is the probability distribution diagram of pore size before and after the pore size changes exponentially in the digital core pore network model.

[0046] Figure 4 Permeability change curve calculated by exponentially changing the pore size of the digital core.

[0047] Figure 5 Permeability change curve calculated by multiple changes in the throat size of the digital core.

[0048] Figure 6 Permeability variation curve calculated by multiple changes in the pore shape factor of the digital core.

[0049] Figure 7 Permeability change curve calculated by multiple changes in the throat shape factor of the digital core.

[0050] Embodiments of the present invention will be described with reference to the accompanying drawings. DETAILED DESCRIPTION

[0051] Example

[0052] like Figure 1 As shown, a rock permeability calculation method based on digital core technology is proposed for this embodiment. The method calculates rock permeability parameters by using numerical simulation method through micro-scale modeling of rock pore structure, and studies the relationship between microstructure and permeability.

[0053] The method specifically includes: (1) constructing a three-dimensional digital core using a micro-nano CT scanning method; (2) establishing a digital core pore network model using a maximum sphere method; (3) extracting pore throat parameters of the pore network model; (4) establishing a new pore network model by quantitatively changing the pore throat parameters; (5) calculating the permeability parameters of the new pore network model; and (6) analyzing the changing relationship between the pore throat parameters and the permeability.

[0054] The above method is further described below in conjunction with the accompanying drawings.

[0055] 1. Micro-nano CT scanning method to construct three-dimensional digital core

[0056] Digital core modeling is the basis for numerical simulation and calculation of rock permeability. With the continuous development of X-ray CT scanning equipment, it is possible to obtain three-dimensional digital cores that characterize the pore structure of rocks by scanning rock samples at the micro-nano scale. The micro-nano CT scanning method uses X-rays to scan non-transparent materials, obtain scanning information related to material density, and construct three-dimensional digital cores by further processing the scanning information. The modeling process can be described as the CT scanning device emitter emitting monochromatic X-rays, so that the X-rays and the sample are kept in the same straight line. The rays penetrate the rock sample located on the operating table, and the detector located in the same straight line receives the X-ray energy signal after penetration. The position of the experimental rock sample is continuously adjusted, and the process is repeated to obtain information on different sections until the entire scanning experiment is completed by rotating 360 degrees. The signal obtained from the scanning experiment is transmitted to the computer for subsequent signal processing, including grayscale image filtering, image binarization, etc., and finally a three-dimensional digital core is established.

[0057] 2. Establishing digital core pore network model using the maximum sphere method

[0058] Digital core is a collection of a large number of 0 and 1 numbers. It is difficult to quantify the pore space characteristics directly based on digital core, and it is also impossible to effectively calculate the permeability parameters and analyze the relationship between permeability and pore structure characteristics. Therefore, it is necessary to establish a pore network model based on digital core, and then calculate the permeability parameters and analyze the pore structure-permeability relationship. The pore network model characterizes the characteristics of digital core by constructing pores and throats. The regional maximum pore space in the digital core is represented by pores, and the channels connecting these pores are represented by throats. The pore network model can better characterize the microstructural characteristics of the actual rock, and help analyze the type, size, connectivity and other characteristics of the actual rock microstructure. The pore network model is a direct model for calculating permeability. Through the pore network model, the relationship between the pore throat parameters and the permeability can be better analyzed, and a permeability evaluation prediction model can be established. The maximum sphere method is an effective method for establishing a digital core pore network model. The method mainly includes the main steps of establishing the regional maximum sphere, establishing the connectivity between the maximum spheres, and identifying pores and throats.

[0059] 2.1 Establishing the largest sphere in the region

[0060] For the constructed digital core, since it is composed of three-dimensional data, in the construction of the pore network model, the position and size of the largest sphere need to be determined. The center position of the largest sphere is represented by a certain pixel position that can be determined. However, the size of the largest sphere is affected by the statistical pixel position, and its value is non-deterministic. There is a pixel error. The minimum and maximum values ​​of the largest sphere are defined as R and R respectively. min and R max .

[0061] The maximum radius R of the largest sphere max Defined as the maximum ball center position C(x c ,y c ,z c ) to the nearest skeleton V g (x g ,y g ,z g )’s straight-line distance:

[0062]

[0063] Where C represents the center position of the largest ball, x c ,y c 、z c Indicates the value of the center position in the three directions of XYZ, V g Indicates the skeleton position closest to the center position, x g ,y g 、z g represents the value of the skeleton position in the three directions of X, Y, and Z. S represents the pore space of the digital core. S g Represents the skeleton of a digital core.

[0064] The minimum radius R of the largest sphere min Defined as the straight-line distance from the center of the largest sphere to the farthest pore space V(x,y,z):

[0065]

[0066] 2.2 Establishing the connectivity between the largest balls

[0067] After establishing the regional maximum sphere, it is necessary to perform link analysis on these maximum spheres. Since a certain maximum sphere only represents the most basic information of the sphere, the relationship between these maximum spheres and the connected link relationship need to be further analyzed, that is, to establish the pore and throat relationship link. Some maximum spheres represent pores, and some maximum spheres represent throats. All maximum spheres are sorted according to the radius size. The maximum spheres with the same radius are grouped into the same group. Link analysis is performed from large to small according to the radius. First, the first group with the largest radius is analyzed. Assuming that the number of maximum spheres in this group is N, the first maximum sphere is set as ancestor A. The maximum spheres with a radius equal to or smaller than A are absorbed by A and become the descendants of A. Then the remaining N-1 spheres are regrouped and sorted. The second sphere is set as B. There are two situations for B. One is that it is absorbed by A and becomes the descendant of A, and the other is that it will not be absorbed by A and becomes an independent ancestor B. A sphere and its absorbed descendants constitute multi-cluster A, and B sphere and its absorbed descendants constitute multi-cluster B. If ancestor A and ancestor B share a descendant, they form a complete link. The shared descendant ball is represented as a throat, and clusters A and B are each represented as a pore, which constitutes a complete pore throat link, such as Figure 2 As shown. Repeat the above steps for all the remaining maximum balls, and the pore and throat links can be established for all the maximum balls.

[0068] 2.3 Pore and throat identification

[0069] Establishing connected links between the maximum spheres forms a complex link network. There are often multiple links between two pores. In order to facilitate the calculation of permeability, it is necessary to merge the multiple links between the two pores into one link, in which the shared child maximum sphere is represented as the throat. The radii of multiple throats are calculated and merged into one throat radius, thus forming a pore throat link. Multi-cluster A and multi-cluster B represent the two pores on this link.

[0070] 3. Extract pore throat parameters of pore network model

[0071] After establishing the pore network model based on the digital core, it is necessary to extract and count the pore throat parameters of the pore network model, which is the necessary data for calculating the permeability parameters, and can better analyze the changing relationship between the pore throat parameters and the permeability. The more important pore throat parameters in the pore network model include pore size, pore shape, throat size, throat shape, coordination number, etc. After establishing the digital core pore network model using the maximum sphere method, the distribution data of the corresponding pore throat parameters can be obtained by calculating these parameters of the model.

[0072] Pores are the larger pore spaces in the digital core. The size of the pores affects the storage and flow of fluids, thereby affecting the permeability. Throats are the smaller pore spaces that connect the larger pore spaces in the digital core. The size of the throats affects the flow of fluids and has a significant impact on the permeability. By calculating these two structural parameters in the pore network model, the pore size distribution and throat size distribution can be obtained.

[0073] The pore space of rocks is very complex and irregular, which makes it difficult to calculate the permeability. Therefore, a parameter is used to represent the complexity and irregularity of the pore space. This parameter is defined as the shape factor, which is divided into two parameters: pore shape and throat shape. These two parameters affect the way and speed of fluid flow in the pore space, thereby affecting the permeability of the rock. The shape factor G is defined as:

[0074]

[0075] Where V is the volume of the pore or throat; L is the length of the pore or throat; A s Represents the surface area of ​​a pore or throat.

[0076] 4. Quantitatively change the pore throat parameters to establish a new pore network model

[0077] This method establishes a new pore network model by quantitatively changing the pore throat parameters of the initial pore network model, thereby providing a model basis for studying the pore structure-permeability relationship. After extracting the pore throat parameters of the pore network model, a new pore network model is established by changing one or more of the pore throat parameters, providing a direct model for calculating rock permeability and exploring its influence law. Pore size, throat size, pore shape, and throat shape are important parameters that affect rock permeability. A new pore network model can be established by changing one or more of these parameters exponentially. In order to quantitatively change the pore throat properties of the pore network model, a new parameter, the deformation factor, is set. By changing this parameter exponentially and multiplying it by a certain pore throat parameter distribution data of the initial pore network model, the pore throat parameter distribution law can be expanded or reduced exponentially, and finally a new pore network model is established.

[0078] On the basis of the initial pore network model, a new parameter, namely the deformation factor, is defined to quantitatively change one or more parameters of the pore network model. The deformation factor multiplied by these parameters is expressed as:

[0079] f1(x)=n×f0(x) (4)

[0080] Where x represents the radius or shape factor of the pore and throat, f0(x) represents the probability distribution of this parameter in the initial pore network model, f1(x) represents the probability distribution of this parameter in the new pore network model, and n represents the deformation factor, which is a natural number.

[0081] Figure 3 The pore size probability distribution before and after the quantitative change of the pore size parameters in the digital core pore network model is shown. The black dots in the figure show the distribution of the pore parameters in the initial pore network model, and the other dots show the distribution of the pore parameters in the new pore network model after multiple increase or decrease. By using the deformation factor, the change law of specific parameters can be controlled, and a new pore network model can be established, so that the permeability of the rock can be calculated by numerical simulation based on the new model, and the model foundation can be laid for further analysis of the relationship between pore structure and permeability.

[0082] 5. Calculate the permeability parameters of the new pore network model

[0083] Compared with the traditional capillary bundle model, the pore network model is closer to the pore structure characteristics of the actual rock, so the calculated permeability is more accurate. Since the pore network model is very complex, in the process of fluid seepage simulation and permeability parameter calculation, it is necessary to make some basic assumptions in the simulation process to simplify the calculation process: the fluid is considered to be incompressible, the multiphase fluid is considered to be incompatible, and the pressure drop in the calculation is considered to be mainly affected by the capillary force.

[0084] Using the new pore network model as a direct calculation platform, permeability calculation is carried out based on quasi-static conditions. This method can consider pore throat parameters from a microscopic scale to calculate rock permeability. The entire permeability calculation process is described as follows: First, set the inlet and outlet of the pore network model, set a certain pressure difference between the inlet and outlet, and the fluid enters from the inlet and flows out from the outlet. Then, the capillary pressure is calculated based on the statistically calculated pore size, throat size, pore shape, throat shape, coordination number and other parameters. The fluid enters the pore throat of the pore network model in turn according to its characteristics. The corresponding flow rate is calculated according to the flow changes of different fluids. At the same time, the size of the entire digital core model, the area of ​​the inlet and the area of ​​the outlet are calculated. Finally, the permeability K of the pore network model is obtained using Darcy's theorem:

[0085]

[0086] Where L represents the total length of the pore network model; A represents the area of ​​the fluid inlet and outlet of the pore network model; μ p represents the viscosity of the p-phase fluid; q p represents the flow rate of the p-phase fluid; P in -P out Indicates the pressure difference between the input and output ends.

[0087] 6. Analyze the relationship between pore throat parameters and permeability

[0088] The change of pore throat parameters affects the size of permeability parameters. By calculating the permeability of the new pore network model, the relationship between permeability and pore throat parameters is analyzed. Figure 4 The permeability change curve calculated by multiple changes in the pore size of the digital core is shown. Figure 5 The permeability change curve calculated by multiple changes in the throat size of the digital core is shown. Figure 6 The permeability variation curve calculated by multiple changes in the pore shape factor of the digital core is shown. Figure 7 The permeability curve calculated by multiplying the throat shape factor of the digital core is shown. Figure 4 The relationship between the pore size and permeability of the analysis model is that as the pore size deformation factor gradually increases from 1, the pore size gradually increases, so the calculated permeability gradually increases, but when the deformation factor is greater than 2, the permeability increases very little; as the pore size deformation factor gradually decreases from 1, the pore size gradually decreases, so the calculated permeability gradually decreases. Figure 6 The changing relationship between pore shape and permeability is shown. As the pore shape deformation factor gradually decreases from 1, the irregularity of the pores decreases, so the permeability gradually increases; as the pore shape deformation factor gradually increases from 1, the irregularity of the pore shape gradually increases, so the permeability gradually decreases; the changing relationship between pore shape and permeability is approximately linear.

[0089] By defining a new parameter deformation factor to control the exponential quantitative change of pore throat parameters, a new pore network model is established, and the curve of permeability parameters changing with pore throat parameters is calculated. The relationship between their changes is analyzed, and the influence of pore structure characteristics on permeability is explored. This method provides a basis for the interpretation of geophysical reservoir properties.

[0090] In summary, this embodiment, based on digital core technology, can construct the rock pore structure from a microscopic scale, quantitatively change the size of rock pore throat parameters by multiples, obtain a large number of new pore network models, and calculate rock permeability by numerical simulation, saving a lot of manpower and material resources. It can obtain rock permeability parameters more conveniently and quickly, and more effectively explore the relationship between pore structure changes and permeability.

[0091] Note that references in the specification to "one embodiment," "an embodiment," "an example embodiment," "some embodiments," etc. indicate that the described embodiments may include a particular feature, structure, or characteristic, but each embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, whether or not explicitly described, it would be within the knowledge of a person skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments.

[0092] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for calculating rock permeability based on digital core technology, characterized in that: include: A core construction step for obtaining a three-dimensional digital core representing the rock pore structure; A model building step is used to establish a pore network model, wherein in the pore network model, the largest pore space in the digital core is represented by pores, and the channels connecting these pores are represented by throats; The pore throat parameter extraction step is used to statistically calculate the pore throat parameters in the pore network model; a permeability calculation step, for obtaining a variation relationship between a permeability parameter and a pore throat parameter according to the pore throat parameter; The model reconstruction step is used to change one or more of the pore throat parameters to establish a new pore network model, and then re-execute the permeability calculation step.

2. The rock permeability calculation method based on digital core technology according to claim 1 is characterized in that: In the network model building step, the maximum sphere method is used to establish a digital core pore network model.

3. The rock permeability calculation method based on digital core technology according to claim 1 is characterized in that: In the pore throat parameter extraction step, the shape factor is calculated based on the following formula: Where V is the volume of the pore or throat; L is the length of the pore or throat; A s Represents the surface area of ​​a pore or throat.

4. The rock permeability calculation method based on digital core technology according to claim 1 is characterized in that: In the permeability calculation step, the permeability of the pore network model is calculated based on the following formula: Where K represents permeability; L represents the total length of the pore network model; A represents the fluid inlet and outlet area of ​​the pore network model; μ p represents the viscosity of the p-phase fluid; q p represents the flow rate of the p-phase fluid; P in -P out Indicates the pressure difference between the input and output ends.

5. The rock permeability calculation method based on digital core technology according to claim 1 is characterized in that: In the model reconstruction step, a new pore network model is formed by quantitatively changing the parameters in the pore network model through the deformation factor based on the following formula: f1(x)=n×f0(x) Where x represents the radius or shape factor of the pore and throat, f0(x) represents the probability distribution of this parameter in the initial pore network model, f1(x) represents the probability distribution of this parameter in the new pore network model, and n represents the deformation factor, which is a natural number.

6. A rock permeability calculation device based on digital core technology, characterized in that: include: Core construction module, used to obtain three-dimensional digital cores representing the rock pore structure; A model building module is used to establish a pore network model, wherein in the pore network model, the largest pore space in the digital core is represented by pores, and the channels connecting these pores are represented by throats; Pore ​​throat parameter extraction module, used to statistically calculate the pore throat parameters in the pore network model; A permeability calculation module, used for obtaining a change relationship between a permeability parameter and a pore throat parameter according to the pore throat parameter; The model reconstruction module is used to change one or more of the pore throat parameters to establish a new pore network model, and then re-execute the permeability calculation module.

7. The rock permeability calculation device based on digital core technology according to claim 6 is characterized in that: In the network model building module, the maximum sphere method is used to establish a digital core pore network model.

8. The rock permeability calculation device based on digital core technology according to claim 6, characterized in that: In the pore throat parameter extraction module, the shape factor is calculated based on the following formula: Where V is the volume of the pore or throat; L is the length of the pore or throat; A s Represents the surface area of ​​a pore or throat.

9. The rock permeability calculation device based on digital core technology according to claim 6, characterized in that: In the permeability calculation module, the permeability of the pore network model is calculated based on the following formula: Where K represents permeability; L represents the total length of the pore network model; A represents the fluid inlet and outlet area of ​​the pore network model; μ p represents the viscosity of the p-phase fluid; q p represents the flow rate of the p-phase fluid; P in -P out Indicates the pressure difference between the input and output ends.

10. The rock permeability calculation device based on digital core technology according to claim 6, characterized in that: In the model reconstruction module, the parameters in the pore network model are quantitatively changed by the deformation factor based on the following formula to form a new pore network model: f1(x)=n×f0(x) Where x represents the radius or shape factor of the pore and throat, f0(x) represents the probability distribution of this parameter in the initial pore network model, f1(x) represents the probability distribution of this parameter in the new pore network model, and n represents the deformation factor, which is a natural number.

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