A method and device for pore throat segmentation of the pore space of a porous medium

Abstract

A method and device for pore-throat segmentation of the pore space of a porous medium. The method includes the following steps: obtaining a binary image of a digital core and removing abnormal voxel points; using the watershed algorithm to determine the central positions of pores and throats; determining the attribution of voxel points in the pore space based on the flow resistance characteristics of the local pore structure; and calculating the geometric parameters of single pores and throats according to the voxel points that make up them. The present invention realizes pore-throat segmentation completely based on the flow resistance of the local pore structure, has clear physical significance and does not contain any adjustable parameters, overcoming the deficiencies of existing methods. The pore network extracted in this application can reliably and accurately predict the single-phase and two-phase flow laws of porous media, which is of great significance for revealing the pore-scale flow mechanism and guiding the development of oil and gas reservoirs; in addition, this application can capture the gradually narrowing and expanding pore structure characteristics between pores and throats, laying a foundation for studying the influence of gradually changing structures on flow in porous media.

Description

Technical Field

[0001] This document relates to the field of image processing, and particularly to a method and apparatus for pore-throat segmentation of the pore space of a porous medium. Background Art

[0002] Porous media seepage widely exists in nature and industrial production, such as blood flow in organisms, oil and gas development, underground pollutant treatment, etc. Digital core technology combined with pore network models is an effective means to predict the seepage characteristics of porous media. A digital core is a digital image generated by 3D imaging and geometric reconstruction of the pore space of a porous medium. This image is represented by a set of binary voxels (1 represents a voxel belonging to the pore space, and 0 represents a voxel belonging to the rock matrix), and can more realistically reflect the spatial distribution and morphological characteristics of the core pores. The cavities with larger sizes and mainly for accommodation in the pore space are called pore bodies, simply referred to as pores; the narrow channels that restrict flow are called throat channels, simply referred to as throats. The pore network model uses idealized geometric bodies to represent pores and throats, and can quickly and effectively simulate the seepage phenomenon in porous media.

[0003] In related technologies, the methods of pore-throat segmentation often contain adjustable parameters and their physical meanings are not clear, which is difficult to ensure the rationality and reliability of pore-throat segmentation. Therefore, a method that can reasonably segment the pore-throat structure is needed. Summary of the Invention

[0004] The following is an overview of the subject matter described in detail in this application. This overview is not intended to limit the scope of protection.

[0005] An embodiment of this application provides a method for pore-throat segmentation of the pore space of a porous medium, which can achieve pore-throat segmentation without any adjustable parameters, and the obtained pore-throat segmentation result has a clear physical meaning, can reflect the flow characteristics of the real pore structure, and improves the accuracy of pore-throat segmentation.

[0006] An embodiment of this application provides a method for pore-throat segmentation of the pore space of a porous medium, including:

[0007] Obtain a grayscale image of the pore space of a porous medium, and perform data processing on the grayscale image to obtain a binary image;

[0008] Convert the binary image into a distance map, and determine the central positions of each pore and throat in the distance map to obtain one or more pore-throat structures; wherein, the distance map is a matrix having the same shape as the binary image, and each element in the matrix represents the distance from the voxel at the corresponding position in the binary image to the nearest wall surface;

[0009] For each determined pore-throat structure, perform the following operations respectively:

[0010] According to the Reynolds number of the internal seepage flow in the porous medium, two pore-throat sub-structures are obtained from the pore-throat structure; wherein, each pore-throat sub-structure contains the central positions of a pore and a throat and at least part of the throat.

[0011] Respectively determine the boundaries of the pore and the throat in each pore-throat sub-structure according to the central positions of the pore and the throat in each pore-throat sub-structure and the flow resistance relationship after cutting.

[0012] Segment the pore and the throat in each pore-throat sub-structure according to the boundary.

[0013] Optionally, the method for segmenting the pore-throat of the pore space of the porous medium further includes:

[0014] After segmenting the pore and the throat in the pore-throat structure according to the boundary, extract the geometric parameters of each segmented pore and throat; the geometric parameters include radius, conduction length, and shape factor.

[0015] Optionally, the obtaining of the binary image by processing the grayscale image includes:

[0016] Perform filtering processing and noise reduction processing on the grayscale image to remove multiple abnormal voxel points in the pore space and obtain a binary image.

[0017] Optionally, the converting the binary image into a distance map and determining the central positions of each pore and throat in the distance map includes:

[0018] Convert the binary image into a distance map, perform Gaussian filtering processing and maximum filtering processing on the distance map, and determine multiple voxel points corresponding to local maximum points in the distance map.

[0019] Using the voxel points corresponding to multiple local maximum points as marker points, divide the pore space into multiple blocks by using a preset algorithm.

[0020] Respectively use the central position of each divided block as the central position of a different pore, and use the central position of each interface between the divided blocks as the central position of a different throat.

[0021] Optionally, the respectively determining the boundaries of the pore and the throat in each pore-throat sub-structure according to the central positions of the pore and the throat in each pore-throat sub-structure and the flow resistance relationship after cutting includes:

[0022] For each pore-throat sub-structure, perform the following operations respectively:

[0023] According to the central positions of the pores and throats in the pore-throat substructure, determine the hydraulic radius corresponding to each of multiple segments from the central position of the throat to the central position of the pore in the pore-throat substructure; wherein, the segments are candidate boundaries.

[0024] For the multiple segments, calculate the flow resistance of each segment respectively according to the hydraulic radius of the segment.

[0025] Determine the boundaries between the pores and throats in the pore-throat substructure according to the flow resistances of the multiple segments.

[0026] Wherein, the hydraulic radius is the maximum distance value from all the first voxel points in the segment to the fixed wall surface; the first voxel points are the voxel points with a voxel value of 1 in the binary image, representing the pore space.

[0027] Optionally, the formula for calculating the flow resistance of the segment is:

[0028]

[0029] Where, W (s) is the flow resistance of segment s, μ represents the fluid viscosity, C is a parameter related to the cross-sectional shape of the segment, Δl s and r (s) represent the length and hydraulic radius of the segment respectively.

[0030] Optionally, the determining the boundaries between the pores and throats in the pore-throat substructure according to the flow resistances of the multiple segments includes:

[0031] Determine the total flow resistance of the pore-throat substructure according to the flow resistances of all the segments in the pore-throat substructure calculated.

[0032] For each segment in the pore-throat substructure, perform the following operations respectively: determine the first cylinder and the second cylinder corresponding to the pore-throat substructure according to the segment, wherein the first cylinder is a cylinder with the radius of the pore in the pore-throat structure as the cross-sectional radius and the distance from the central position of the pore to the central point of the segment as the height; the second cylinder is a cylinder with the radius of the throat in the pore-throat structure as the cross-sectional radius and the distance from the central position of the throat to the central point of the segment as the height; calculate the sum of the flow resistances of the two cylinders corresponding to the segment.

[0033] Calculate the relative error between the sum of the flow resistances of the cylinders and the total flow resistance of the pore-throat substructure.

[0034] Determine the segment with the minimum relative error as the boundary between the throat and the pore in the pore-throat substructure.

[0035] Optionally, the total flow resistance of the pore-throat substructure is:

[0036]

[0037] In the above formula, W total represents the total flow resistance of the pore-throat sub-structure;

[0038] The sum of the flow resistances of the first cylinder and the second cylinder is:

[0039]

[0040] In the above formula, W PNM represents the sum of the flow resistances of the first cylinder and the second cylinder, l t represents the length of the cylinder, which is the distance from the center of the throat to the center of the segmentation boundary, l p represents the length of the cylinder, which is the distance from the center of the pore to the center of the segmentation boundary.

[0041] Optionally, the relative error ΔE between the sum of the flow resistances of the cylinder and the total flow resistance of the pore-throat sub-structure is:

[0042]

[0043] An embodiment of the present application also provides a device for pore-throat segmentation of the pore space of a porous medium, including: a memory and a processor;

[0044] The memory is used to store a program for pore-throat segmentation of the pore space of a porous medium;

[0045] The processor is used to read and execute the program for pore-throat segmentation of the pore space of a porous medium, and perform the method for pore-throat segmentation of the pore space of a porous medium as described in any one of claims 1-9.

[0046] Compared with the related art, the beneficial effects of the present application include:

[0047] The pore-throat segmentation is completely based on the flow resistance of the local pore structure, has clear physical meaning and does not contain any adjustable parameters. The pore-throat segmentation result can better reflect the flow characteristics of the real pore space, can reliably and accurately predict the single-phase and two-phase seepage laws of porous media, and is of great significance for revealing the pore-scale flow mechanism and guiding the development of oil and gas reservoirs.

[0048] Other aspects can be understood after reading and understanding the drawings and the detailed description. Description of the Drawings

[0049] The drawings are used to provide an understanding of the technical solutions of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solutions of the present application, and do not constitute a limitation to the technical solutions of the present application.

[0050] Figure 1It is a flowchart of a method for implementing pore-throat segmentation of the pore space of a porous medium in an embodiment of the present application;

[0051] Figure 2 It is a schematic diagram of a binarized image after removing abnormal voxel points in an embodiment of the present application;

[0052] Figure 3 It is a schematic diagram of dividing the "pore 1 - throat - pore 2" structure into two sub - structures of "throat - pore 1" and "throat - pore 2" in an embodiment of the present application;

[0053] Figure 4 It is a schematic diagram of the swelling process and its corresponding pore and throat segmentation in an embodiment of the present application;

[0054] Figure 5 It is a schematic diagram of the final voxel point attribution of the "pore 1 - throat - pore 2" structure in an embodiment of the present application;

[0055] Figure 6 It is a schematic diagram of a device for implementing pore - throat segmentation of the pore space of a porous medium in an embodiment of the present application. Detailed implementation manners

[0056] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those of ordinary skill in the art that there can be more embodiments and implementation solutions within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the detailed implementation manners, many other combination ways of the disclosed features are also possible. Unless specifically restricted, any feature or element of any embodiment can be combined with any other feature or element in any other embodiment, or can replace any other feature or element in any other embodiment.

[0057] The present application includes and contemplates combinations with features and elements known to those of ordinary skill in the art. The embodiments, features, and elements already disclosed in the present application can also be combined with any conventional features or elements to form unique invention solutions. Any feature or element of any embodiment can also be combined with features or elements from other invention solutions to form another unique invention solution. Therefore, it should be understood that any feature shown and / or discussed in the present application can be implemented alone or in any suitable combination. In addition, various modifications and changes can be made within the scope of protection.

[0058] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not depend on the specific order of the steps described herein, the method or process should not be limited to the specific order of steps described. As those of ordinary skill in the art will understand, other step orders are possible. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation on the embodiments. In addition, regarding the method and / or process not being limited to performing their steps in the order written, those skilled in the art can readily understand that these orders can be varied and still remain within the spirit and scope of the embodiments of the present application.

[0059] In addition, in the present application, descriptions such as "first", "second", etc. are only used for distinction in the description, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0060] In the process of predicting the seepage characteristics of porous media, in order to obtain accurate and reliable pore network simulation results, it is necessary to extract a pore network representative of the structural characteristics of the porous media from the digital core, which includes three main steps, namely, the determination of the center positions of pores and throats, the segmentation of pores and throats, and the calculation of the geometric parameters of pores and throats. Currently, the methods for determining the center positions of pores and throats and calculating geometric parameters are relatively mature and perfect, such as the middle axis method, the maximum sphere method, the watershed method, etc., but the methods for pore-throat segmentation often contain adjustable parameters and unclear physical meanings, which is difficult to ensure the rationality and reliability of pore-throat segmentation. Therefore, reasonably segmenting pores and throats is the key to accurately characterizing the pore structure characteristics and is also a prerequisite for obtaining a representative pore network.

[0061] The method for pore-throat segmentation of the pore space of the porous media in the present application is applicable to digital cores. Below, a digital core with a sandstone structure will be taken as an example for illustration, and digital cores with other geological structures can use the pore-throat segmentation method of the present application with reference to the following examples.

[0062] The embodiments of the present application provide a method for pore-throat segmentation of the pore space of porous media, as Figure 1 shown, including:

[0063] Step 100: Obtain a grayscale image of the pore space of the porous media, and perform data processing on the grayscale image to obtain a binary image.

[0064] Step 101: Convert the binary image into a distance map, determine the central positions of each pore and throat in the distance map, and obtain one or more pore-throat structures; wherein, the distance map is a matrix having the same shape as the binary image, and each element in the matrix represents the distance from the voxel point at the corresponding position in the binary image to the nearest wall surface;

[0065] Step 102: For each determined pore-throat structure, perform the following operations respectively:

[0066] According to the Reynolds number of the internal seepage flow in the porous medium, obtain two pore-throat sub-structures from the pore-throat structure; wherein, each pore-throat sub-structure contains the central positions of a pore and a throat and at least part of the throat.

[0067] Step 103: Determine the boundaries of the pore and the throat in each pore-throat sub-structure respectively according to the central positions of the pore and the throat in each pore-throat sub-structure and the flow resistance relationship after cutting.

[0068] Segment the pore and the throat in each pore-throat sub-structure according to the boundary.

[0069] In this embodiment, the gray-scale image of the pore space can be obtained through CT scanning of the sandstone core and geometric reconstruction technology, and then a binary image can be obtained by selecting an appropriate threshold. The situation of obtaining the gray-scale image by other means is similar and will not be elaborated here. The voxel points with a voxel value of 1 in the binary image represent the pore space; the voxel points with a voxel value of 0 represent the solid skeleton, and the obtained binary image is as Figure 2 shown.

[0070] In an exemplary embodiment, the converting the binary image into a distance map, determining the central positions of each pore and throat in the distance map, and obtaining one or more pore-throat structures includes:

[0071] Convert the binary image into a distance map, perform Gaussian filtering processing and maximum filtering processing on the distance map, and determine a plurality of voxel points corresponding to the local maximum points in the distance map;

[0072] Using the voxel points corresponding to the plurality of local maximum points as marker points, divide the pore space into a plurality of blocks by using a preset algorithm;

[0073] Taking the central position of each divided block as the central position of a different pore respectively, and taking the central position of each interface between the divided blocks as the central position of a different throat respectively, to obtain one or more pore-throat structures.

[0074] In this exemplary embodiment, a distance transformation is performed on the grayscale image of the pore space of the porous medium to obtain a distance map. Gaussian filtering and maximum filtering operations are sequentially performed on the distance map to determine the voxel points corresponding to the local maxima in the distance map. Using the voxel points corresponding to the maximum points as markers, the pore space is divided into several blocks by means of the watershed algorithm. The central positions of each block and the central positions of the interfaces between blocks respectively correspond to the central positions of the pores and throats, and the distance value at each maximum point is the radius R of the pore p and the distance value at the central position of the interface between adjacent blocks is the radius R of the throat t .

[0075] In this embodiment, since the Reynolds number of the seepage flow in the porous medium is extremely low, each "pore1-throat-pore2" structure ( Figure 3 the part on the left side of the equal sign) can be divided into two sub-structures of "throat-pore1" and "throat-pore2" ( Figure 3 the two added parts on the right side of the equal sign), as shown in Figure 3 . Among them, each pore-throat sub-structure contains a pore and at least part of the throat. For example, the sub-structure on the left side of the plus sign includes the pore 2 with the central position at p2 and part of the throat, and the sub-structure on the right side of the plus sign includes the pore 1 with the central position at p1 and part of the throat; the throats in the two sub-structures both contain the central position t of the throat, and the union is the throat in the pore-throat structure

[0076] In an exemplary embodiment, the method for pore-throat segmentation of the pore space of the porous medium further includes:

[0077] After segmenting the pores and throats in the pore-throat structure according to the boundary, extracting the geometric parameters of each segmented pore and throat; the geometric parameters include radius, conduction length, and shape factor

[0078] In this embodiment, the corresponding geometric parameters can be calculated based on the set of voxel points that make up each pore and throat. For example, the radius of the pore and throat is equal to the shortest distance from their respective central voxel points to the wall; the volume of the pore and throat is equal to the number of voxel points multiplied by the volume of a single voxel point; the conduction length of the pore and throat is equal to the distances from the pore center and the throat center to the boundary center along the connection path; the shape factor G of the pore and throat is the square of the radius R divided by four times the cross-sectional area A, and the calculation formula is:

[0079] In an exemplary embodiment, the data processing of the grayscale image to obtain a binary image includes:

[0080] Performing filtering processing and noise reduction processing on the grayscale image to remove a plurality of abnormal voxel points in the pore space and obtain a binary image

[0081] In this embodiment, preprocessing such as filtering and noise reduction is performed on the grayscale image of the pore space of the porous medium, and abnormal voxel points in the pore space, such as isolated voxel points, are removed to obtain a binary image.

[0082] In an exemplary embodiment, determining the boundaries of the pores and throats in each of the pore-throat substructures respectively according to the central positions of the pores and throats in each of the pore-throat substructures and the flow resistance relationship after cutting includes:

[0083] The following operations are respectively performed on each pore-throat substructure:

[0084] According to the central positions of the pore and the throat in the pore-throat substructure, determine the hydraulic radius corresponding to each of multiple segments from the central position of the throat to the central position of the pore in the pore-throat substructure; wherein, the segments are candidate boundaries.

[0085] For the multiple segments, calculate the flow resistance of each segment respectively according to the hydraulic radius of the segment.

[0086] Determine the boundaries of the pores and throats in the pore-throat substructure according to the flow resistances of the multiple segments.

[0087] Wherein, the hydraulic radius is the maximum distance value from all the first voxel points in each segment to the fixed wall surface; wherein, the first voxel points are the voxel points with a voxel value of 1 in the binary image, representing the pore space.

[0088] In this exemplary embodiment, referring to Figure 3 and Figure 4 , taking the "throat - pore 1" substructure as an example, the pore - throat segmentation process is analyzed in detail. Starting from the central position t of the throat, expanding towards the central position p1 of the adjacent pore 1, each time the newly absorbed voxel points during the expansion form a segment s, and record the hydraulic radius r of each segment (s) , and calculate the flow resistance of this segment accordingly:

[0089]

[0090] Wherein, μ represents the fluid viscosity, C is a parameter related to the cross-sectional shape of the segment. For example, when the cross-section is circular, square, and triangular, the corresponding C values are 0.0796, 0.0625, and 0.0481 respectively, Δl s and r (s) respectively represent the length and hydraulic radius of the segment.

[0091] In this exemplary embodiment, the expansion process continues until the new segment reaches the central position of the adjacent pore. Assuming that the cross-sectional shape from the throat center t to the pore 1 center p1 remains unchanged, then the total flow resistance of the pore-throat substructure can be expressed as:

[0092]

[0093] Among them, W total represents the total flow resistance of the pore throat sub-structure.

[0094] In this exemplary embodiment, each segment is a potential division boundary between the throat and pore 1. In each possible division scheme (i.e., the division scheme with each segment as the boundary), the pore structure from the center t of the throat to the center p1 of pore 1 can be simplified into two cylinders with radii corresponding to the radius of the throat and the pore respectively, and the lengths of the cylinders are the distances l from the center position t of the throat and the center position p1 of pore 1 to the center of the division boundary (i.e., the corresponding segment in this division scheme). t l p As shown in the appendix Figure 4 shown. Based on this, the sum of the flow resistances of the cylinders can be calculated as:

[0095]

[0096] Among them, W PNM represents the sum of the flow resistances of the first cylinder and the second cylinder, that is, the sum of the flow resistances of the two simplified cylinders in the pore network model. l t represents the length of the cylinder as the distance from the center of the throat to the center of the division boundary, and l p represents the length of the cylinder as the distance from the center of the pore to the center of the division boundary.

[0097] In this embodiment, during the expansion process, the hydraulic radius of the pore structure from the center of the throat to the center of the pore is obtained successively, which can capture the characteristics of the gradually narrowing - gradually expanding pore structure between the pore and the throat, laying a foundation for studying the influence of the gradually changing structure on the flow in porous media.

[0098] In one exemplary embodiment, the relative error ΔE between the sum of the flow resistances of the first cylinder and the second cylinder and the total flow resistance of the pore throat sub-structure is:

[0099]

[0100] In this embodiment, the final boundary s between the throat and pore 1 b1 is determined as the segment with the minimum relative error ΔE. The boundary s between the throat and pore 2 can be determined similarly. All the voxel points between the two boundaries s b2 form the throat, and the remaining pixel points belong to the originally corresponding pore. Thus, the pore throat segmentation of a single "pore 1 - throat - pore 2" structure is completed, and the result is as shown in b1 s b2 Figure 5 shown. By adopting the above method for all the throats, the pore throat segmentation of the entire pore space can be realized, and finally each voxel point in the pore space is clearly assigned to a certain pore or throat. ​

[0101] It can be seen that, compared with the pore throat segmentation method in the related art, the pore throat segmentation result obtained in the embodiment of the present application has a clear physical meaning and the segmentation process does not include any adjustable parameters. The pore throat segmentation result obtained according to this method can better reflect the flow characteristics of the real pore structure, can reliably and accurately predict the single-phase and two-phase seepage laws of porous media, and improves the accuracy of pore throat segmentation.

[0102] The embodiment of the present application also provides a device for pore throat segmentation of the pore space of a porous media. Refer to Figure 6 , including: a memory 601 and a processor 602;

[0103] The memory 601 is used to store a program for pore throat segmentation of the pore space of a porous media;

[0104] The processor 602 is used to read and execute the program for pore throat segmentation of the pore space of a porous media, and perform the method for pore throat segmentation of the pore space of a porous media in any of the above embodiments.

[0105] Those of ordinary skill in the art can understand that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, and their appropriate combinations. In the hardware implementation, the division of the functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, one physical component can have multiple functions, or one function or step can be executed by several physical components in cooperation. Some components or all components can be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or be implemented as hardware, or be implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cassette, tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those of ordinary skill in the art, a communication medium typically includes computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and can include any information delivery medium.

Claims

1. A method for pore throat segmentation of the pore space of a porous medium, characterized in that, The method includes: Obtaining a grayscale image of the pore space of the porous medium and performing data processing on the grayscale image to obtain a binary image; Converting the binary image into a distance map, determining the central positions of each pore and throat in the distance map, and obtaining one or more pore-throat structures; wherein, the distance map is a matrix having the same shape as the binary image, and each element in the matrix represents the distance from the voxel point at the corresponding position in the binary image to the nearest wall surface; For each determined pore-throat structure, the following operations are respectively performed: According to the Reynolds number of the internal seepage of the porous medium, two pore-throat sub-structures are obtained from the pore-throat structure; wherein, each pore-throat sub-structure contains the central positions of a pore and a throat and at least part of the throat; Respectively determining the boundaries of the pore and the throat in each pore-throat sub-structure according to the central positions of the pore and the throat in each pore-throat sub-structure and the flow resistance relationship after cutting; Segmenting the pore and the throat in each pore-throat sub-structure according to the boundary.

2. The method for pore throat segmentation of the pore space of a porous medium according to claim 1, characterized in that It further includes: After segmenting the pore and the throat in the pore-throat structure according to the boundary, extracting the geometric parameters of each segmented pore and throat; the geometric parameters include radius, conduction length, and shape factor.

3. The method for pore throat segmentation of the pore space of a porous medium according to claim 1, characterized in that, The performing data processing on the grayscale image to obtain a binary image includes: Performing filtering processing and noise reduction processing on the grayscale image to remove a plurality of abnormal voxel points in the pore space and obtain a binary image.

4. The method for pore throat segmentation of the pore space of a porous medium according to claim 3, wherein The converting the binary image into a distance map and determining the central positions of each pore and throat in the distance map includes: Converting the binary image into a distance map, performing Gaussian filtering processing and maximum filtering processing on the distance map, and determining a plurality of voxel points corresponding to the local maximum points in the distance map; Using the voxel points corresponding to the plurality of local maximum points as marker points and dividing the pore space into a plurality of blocks by using a preset algorithm; Taking the central position of each divided block as the central position of a different pore respectively, and taking the central position of each interface between the divided blocks as the central position of a different throat respectively.

5. The method for pore throat segmentation of the pore space of a porous medium according to claim 3, characterized in that The respectively determining the boundaries of the pore and the throat in each pore-throat sub-structure according to the central positions of the pore and the throat in each pore-throat sub-structure and the flow resistance relationship after cutting includes: For each pore-throat sub-structure, the following operations are respectively performed: According to the central positions of the pore and the throat in the pore-throat sub-structure, determining the hydraulic radius corresponding to each of a plurality of segments from the central position of the throat to the central position of the pore in the pore-throat sub-structure; wherein, the segment is a candidate boundary; For the plurality of segments, respectively calculating the flow resistance of the segment according to the hydraulic radius of the segment; Determining the boundaries of the pore and the throat in the pore-throat sub-structure according to the flow resistances of the plurality of segments; Wherein, the hydraulic radius is the maximum distance value from all first voxel points in each segment to the fixed wall surface; wherein, the first voxel point is a voxel point with a voxel value of 1 in the binary image, representing the pore space.

6. The method for pore throat segmentation of the pore space of a porous medium according to claim 5, characterized in that, The formula for calculating the flow resistance of the segment is: Among them, W (s) is the flow resistance of the segment s, μ represents the fluid viscosity, C is a parameter related to the cross-sectional shape of the segment, Δl s and r (s) represent the length and hydraulic radius of the segment, respectively.

7. The method for pore throat segmentation of the pore space of a porous medium according to claim 6, characterized in that, The determining the boundaries of the pore and the throat in the pore-throat sub-structure according to the flow resistances of the plurality of segments includes: Determine the total flow resistance of the pore-throat sub-structure according to the flow resistances of all segments in the calculated pore-throat sub-structure; For each segment in the pore-throat sub-structure, perform the following operations respectively: Determine the first cylinder and the second cylinder corresponding to the pore-throat sub-structure according to the segment, where the first cylinder is a cylinder with the radius of the pore in the pore-throat structure as the cross-sectional radius and the distance from the center position of the pore to the center point of the segment as the height; the second cylinder is a cylinder with the radius of the throat in the pore-throat structure as the cross-sectional radius and the distance from the center position of the throat to the center point of the segment as the height; Calculate the sum of the flow resistances of the two cylinders corresponding to the segment; Calculate the relative error between the sum of the flow resistances of the cylinders and the total flow resistance of the pore-throat sub-structure; Determine the segment with the smallest relative error as the boundary between the throat and the pore in the pore-throat sub-structure.

8. The method for pore-throat segmentation of the pore space of a porous medium according to claim 7, characterized in that The total flow resistance of the pore-throat sub-structure is: In the above formula, W total represents the total flow resistance of the pore throat sub-structure; The sum of the flow resistances of the cylinders is: In the above formula, W PNM represents the sum of the flow resistances of the first cylinder and the second cylinder, l t represents the length of the cylinder, which is the distance from the center of the throat to the center of the dividing boundary, l p represents the length of the cylinder, which is the distance from the center of the hole to the center of the dividing boundary, R p represents the radius of the hole, R t represents the radius of the throat.

9. The method for pore throat segmentation of the pore space of a porous medium according to claim 8, characterized in that, The relative error ΔE between the sum of the flow resistances of the cylinders and the total flow resistance of the pore-throat sub-structure is:

10. An apparatus for pore-throat segmentation of the pore space of a porous medium, comprising: A memory and a processor; Characterized in that: The memory is used to store a program for pore-throat segmentation of the pore space of a porous medium; The processor is used to read and execute the program for pore-throat segmentation of the pore space of a porous medium, and perform the method for pore-throat segmentation of the pore space of a porous medium according to any one of claims 1-9.

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