Geometric reconstruction method of tight reservoir rock micro-pore communication network

Abstract

The invention provides a geometric reconstruction method for a tight reservoir rock micro-pore communication network. Geometric data of each pore node in the target reservoir core are obtained, a pore node set is constructed, and the pore nodes comprise pore center coordinates and pore radiuses; establishing a pore-throat topology network based on the connection relationship between the pore nodes; based on the spatial relationship of the connected pore nodes, calculating the pore center distance between the pore nodes, and judging the type of the throat according to the pore center distance; aiming at different throat types, constructing corresponding throat geometries; calculating a throat equivalent scale according to the throat geometry; according to the throat type and the throat equivalent scale, fusing a pore-throat topology network; and based on the fused pore-throat topology network, counting communication characteristics between pore nodes, and reconstructing a tight reservoir pore communication structure. According to the method, automatic identification and refined expression of the pore-throat communication structure are realized through a geometric discrimination and structure reconstruction combined method.

Description

Technical Field

[0001] This application relates to the field of oil and gas exploration and development technology, and in particular to a geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks. Background Technology

[0002] Tight reservoirs are characterized by small pore size, complex pore-throat structure, and strong heterogeneity. Their microscopic pore connectivity directly determines the seepage behavior of fluids in the reservoir and the development effect. Accurately reconstructing the spatial distribution and connectivity of pores and throats in tight reservoir rocks is a key foundation for understanding the physical properties of tight reservoirs, establishing digital core models, and conducting microscopic seepage research.

[0003] With the development of X-ray CT scanning and digital core technology, it is possible to obtain spatial distribution information of rock pores, as well as pore center coordinates and pore scale parameters. However, in existing studies, the methods for constructing pore-throat structures mostly rely on regular geometric assumptions, simplifying pores or throats into ideal spheres, cylinders, or equivalent structures of fixed scale. This makes it difficult to truly reflect the actual geometric relationships and connectivity characteristics of pores and throats in tight reservoirs. On the other hand, while some pore network models can describe the topological connectivity between pores, they often ignore the geometric constraints between pores and fail to comprehensively consider the influence of geometric factors such as pore center distance and pore scale differences on throat morphology. This results in the constructed pore-throat structures lacking physical consistency at the geometric level, making it difficult to meet the needs of refined structural analysis and subsequent numerical simulations.

[0004] Therefore, how to achieve automatic identification, geometric reconstruction, and quantitative parameter reconstruction of pore-throat structure based directly on digital core pore data without introducing additional empirical assumptions, by integrating pore spatial location, pore size, and connectivity between pores, is an urgent problem to be solved in the current research on the microstructure of tight reservoirs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application proposes a geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks.

[0006] Firstly, this application proposes a geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks, including:

[0007] Obtain the geometric data of each pore node in the core of the target reservoir, and construct a set of pore nodes, wherein the pore nodes include the coordinates of the pore center and the pore radius;

[0008] Based on the connection relationships between pore nodes in the pore node set, a pore-throat topology network is established;

[0009] Based on the spatial relationship between connected pore nodes in the pore node set, the center-to-center distance between pore nodes is calculated, and the throat type is determined according to the center-to-center distance between pore nodes.

[0010] For different throat types, construct corresponding throat geometry;

[0011] Calculate the equivalent dimensions of the throat based on the described throat geometry;

[0012] Based on the throat type and throat equivalent scale, a pore-throat topology network is fused.

[0013] Based on the fused pore-throat topology network, the connectivity characteristics between pore nodes are statistically analyzed to reconstruct the pore connectivity structure of tight reservoirs.

[0014] Optionally, the step of determining the throat type based on the center-to-center distance between pore nodes includes:

[0015] When the center-to-center distance of the pores is greater than the sum of the radii of the two pores, it is determined to be a bonded throat.

[0016] When the center-to-center distance of the pores is greater than the difference between the radii of the two pores but less than the sum of the radii of the two pores, it is determined to be a cylindrical throat.

[0017] When the center distance between two pores is less than the difference in their radii, it is determined to be a merged pore structure.

[0018] When the center-to-center distance between the two pores is equal to the sum of their radii or the difference between their radii, it is determined to be a tangential throat.

[0019] Optionally, it further includes: for the cylindrical throat or the tangential throat, determining the main extension direction of the throat by calculating the unit direction vector of the line connecting the centers of any pair of connected pore nodes.

[0020] Optionally, it also includes: determining the lateral boundary position of the throat geometry by calculating a normal vector perpendicular to the unit direction vector;

[0021] Based on the unit direction vector and the normal vector, the polygonal geometric boundary vertices of the cylindrical throat or the tangent throat are determined.

[0022] Optionally, the polygonal geometric boundary vertices of the cylindrical throat or tangent throat are determined based on the unit direction vector and the normal vector, and the calculation formula is as follows:

[0023] ;

[0024] in, For the i-th pore node The horizontal x-coordinate of the center coordinate, For the j-th pore node The horizontal x-coordinate of the center coordinate, For the i-th pore node The vertical ordinate of the center coordinate, For the j-th pore node The vertical ordinate of the center coordinate, Let be the component of the throat normal vector along the z-axis. Let be the component of the throat normal vector along the y-axis. For the i-th pore node The corresponding pore radius, For the j-th pore node The corresponding pore radius.

[0025] Optionally, it further includes: for the bonded throat, constructing the geometry of the bonded throat by the location of the contraction point, and calculating the expression for the location of the contraction point as follows:

[0026] ;

[0027] in, The contraction point of the bonded larynx to the first The distance;

[0028] Connected pore nodes and The distance between the centers of the holes For the i-th pore node The corresponding pore radius, For the j-th pore node The corresponding pore radius.

[0029] Optionally, calculating the equivalent dimensions of the throat based on the throat geometry includes:

[0030] Calculate the geometric area of ​​any throat. ;

[0031] Based on the area of ​​the geometric body Based on the principle of area equivalence, the equivalent radius of the throat is determined by the following formula:

[0032] ;

[0033] in, The area of ​​the geometric solid is The equivalent radius of the larynx is used to characterize the equivalent scale of the larynx; k is the kth larynx.

[0034] Optionally, the statistical analysis of the connectivity features between pore nodes to reconstruct the pore connectivity structure of the tight reservoir includes completing the coordination number distribution by statistically analyzing the coordination number of each pore node, and reconstructing the pore connectivity structure of the tight reservoir based on the coordination number distribution.

[0035] The formula for calculating the coordination number of each pore node is as follows:

[0036] ;

[0037] in, For the i-th pore node The coordination number represents the number of throats connected to a single pore node; It is a binary indicator variable used to determine the i-th pore node. With the j-th pore node Does a connectivity relationship exist? j is the index of the pore node, ranging from 1 to n; n is the total number of pore nodes.

[0038] In a second aspect, a computer storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the geometric reconstruction method for the micropore interconnection network of tight reservoir rocks described in the first aspect.

[0039] The beneficial effects of the technical solutions provided in some embodiments of this application include at least the following:

[0040] (1) This application does not make any prior assumptions about the geometry of pores or throats, and the reconstruction results can truly reflect the microstructure characteristics of tight reservoirs.

[0041] (2) This application achieves automatic identification and refined representation of pore-throat connectivity structures by combining geometric discrimination and structural reconstruction.

[0042] (3) This application achieves multi-scale quantitative characterization of the pore structure of tight reservoirs by statistically analyzing parameters such as pore radius, throat equivalent radius and coordination number;

[0043] (4) This application provides a reliable geometric basis for subsequent tight reservoir flow simulation, pore structure evaluation and development scheme optimization. Attached Figure Description

[0044] Figure 1 This is a flowchart illustrating the geometric reconstruction method of the micropore interconnection network of tight reservoir rocks as shown in the embodiments of this application;

[0045] Figure 2 This is a schematic diagram of the pore connectivity structure shown in the embodiment of this application;

[0046] Figure 3 This is a detailed diagram of the pore connectivity shown in the embodiments of this application;

[0047] Figure 4 This is a diagram showing the aperture radius distribution in an embodiment of this application;

[0048] Figure 5 This is a diagram showing the equivalent radius distribution of the throat as illustrated in the embodiments of this application;

[0049] Figure 6 This is a diagram showing the pore coordination number distribution in an embodiment of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0051] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0052] Existing technologies often rely on regular geometric assumptions, neglecting the geometric constraints between pores and failing to comprehensively consider the influence of geometric factors such as pore center distance and pore size differences on throat morphology. This application's spatial combination method, by first identifying the throat type, then constructing the throat geometry accordingly, and finally achieving seamless connection based on geometric parameters, completes an innovative design combining geometric identification and structural reconstruction, overcoming the shortcomings of existing technologies.

[0053] Example 1

[0054] This application proposes a geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks. Its core lies in determining the spatial geometric relationship between pores and throats based on digital core data, and achieving refined geometric reconstruction of the pore connectivity structure. The method is as follows: Figure 1 As shown, it includes the following steps:

[0055] Step S1: Obtain the geometric data of each pore node in the target reservoir core and construct a pore node set, wherein the pore node includes the pore center coordinates and pore radius;

[0056] Specifically, in this embodiment, the spatial coordinate information and corresponding pore radius parameters of each pore are extracted from the digital core, and the pore center coordinates and pore radius are used as the basic data for pore geometric representation.

[0057] A digital core model was constructed based on rock CT scan data. Image segmentation and skeleton extraction were performed on the digital core to obtain the spatial location and geometric scale parameters of each independent pore. Each pore is represented by its geometric center point, and the i-th pore node is denoted as [i-th pore node]. The geometric center point of (i.e., the i-th pore) is Its 3D coordinates are ;

[0058] Simultaneously extract the equivalent radius of the corresponding pores. Thus, a set of pore nodes is established;

[0059] This step provides the basic spatial and scale information for subsequent pore connectivity determination and geometric reconstruction.

[0060] Specifically, obtain the i-th pore node. Geometric center point coordinates and corresponding equivalent radius Let i be any positive integer, and let the i-th aperture node be... Represented as:

[0061]

[0062] in, Characterizes the spatial location of the i-th pore node in the digital core. The geometric scale of the i-th pore node is used for subsequent throat discrimination and geometry construction.

[0063] Step S2: Based on the connection relationship between pore nodes in the pore node set, establish a pore-throat topology network;

[0064] Based on the pore number and its connection information, the connectivity between pores is determined, and each pair of interconnected pores is identified as a potential throat, thereby constructing a pore-throat topology network structure.

[0065] Specifically, based on the spatial proximity relationship and skeleton connectivity information between pores in the digital core, it is determined whether there is a direct connection between pores; when there is a connected skeleton between the i-th pore node and the j-th pore node, it is considered that the two are connected through a throat, and a connecting edge is established in the pore-throat topology network, thereby constructing a complete pore-throat topology network structure.

[0066] This topology only describes the connections between pores and does not involve specific geometric shapes.

[0067] Specifically, a set of connected pairs of pore nodes is constructed based on the connection number information between pore nodes. :

[0068] ;

[0069] in, Represents pore nodes With pore nodes They are spatially interconnected, so that each connected pair is regarded as a potential throat, which is used to construct a pore-throat topology network.

[0070] Step S3: Based on the spatial relationship between connected pore nodes in the pore node set, calculate the center-to-center distance between pore nodes, and determine the throat type based on the center-to-center distance between pore nodes;

[0071] Specifically, in this embodiment, the center-to-center distance of any pair of connected pores is calculated, and the spatial relationship between the pores is determined by combining the pore radius parameter of the connected pores, thereby identifying different types of throat structures or pore merging relationships.

[0072] Based on the spatial geometric relationship of the connected pores, the center-to-center distance of the pores is calculated and the geometric type of the throat is determined; the specific process is as follows:

[0073] For any pair of interconnected pore nodes With pore nodes Calculate the center distance of the holes:

[0074] ;

[0075] The distance between the center points of the pores is compared with the sum of the radii of the two pores to determine the geometric relationship between the pores; when the following conditions are met:

[0076] ;

[0077] Determine whether there is an independent throat structure between the two pores; when the following conditions are met:

[0078] ;

[0079] If two pores are geometrically overlapping or in high contact, they can be considered as pore merging or without obvious throat structure.

[0080] This criterion is used to distinguish between "pore-throat-pore" structures and "direct contact between pores".

[0081] Specifically, for any pair of connected pore nodes and Calculate the center distance of the holes:

[0082] ;

[0083] Among them, the distance between the centers of the holes It is used to characterize the spatial spacing between connected pores and is a fundamental parameter for determining the geometry of the throat.

[0084] Further calculations were performed on the sum and difference of the radii of the two pores:

[0085] ;

[0086] The sum and difference of the radii are used to compare with the center distance of the holes to reflect the spatial contact or separation state between the holes.

[0087] The specific judgment process is as follows:

[0088] When satisfied When the pores are identified as having bonded throats, this type indicates the presence of significant gaps between the pores.

[0089] When satisfied When the pores are identified as cylindrical throats, it indicates the existence of continuous channels between them.

[0090] When satisfied When the structure is identified as a merged pore structure, it means that the small pores are geometrically covered by the large pores.

[0091] When satisfied or At that time, it was determined to be a tangential larynx.

[0092] It is understandable that the connection relationship between pore nodes is essentially a topological relationship (qualitative: whether or not connected), which only determines "whether there is a connection" and does not involve geometric parameters. It is used to establish a pore-throat topological network (to determine connected pairs). The spatial relationship between connected pore nodes is essentially a geometric relationship (quantitative: the specific state of connection), which includes the center-to-center distance, relative position, radius difference, etc. It is used to calculate the center-to-center distance, determine the throat type, and construct the throat geometry. Those skilled in the art will not be unable to implement the above steps due to this difference in the specific implementation process.

[0093] Step S4: Construct corresponding larynx geometric models for different larynx types;

[0094] Specifically, in this embodiment, the position of the throat's geometric boundary is determined based on the direction of the line connecting the pore centers and its perpendicular direction, and the throat structure is approximated using polygonal geometry to achieve the construction of the throat's geometric shape.

[0095] When pore nodes With pore nodes When a throat structure is determined to exist, a corresponding throat geometric model is constructed based on the pore center-to-center distance and pore size parameters; the throat axis direction is determined by the line connecting the centers of the two pores, and the throat length can be expressed as:

[0096] ;

[0097] Furthermore, throat geometry is generated between the boundaries of the pore geometry, thereby realizing the spatial splicing of the pore geometry and throat geometry and completing the geometric reconstruction of the pore-throat connected structure.

[0098] This step transforms the topological relationships into a visual, computable real geometric structure.

[0099] Specifically, for cylindrical or tangential throats, the unit direction vector of the line connecting the pore centers is calculated using the following formula. :

[0100] ;

[0101] The unit direction vector is used to determine the main extension direction of the throat in space;

[0102] Furthermore, the normal vector perpendicular to the unit direction vector is calculated using the following formula. :

[0103] ;

[0104] in, Used to determine the location of the lateral boundary of the throat geometry.

[0105] For bonded larynxes, calculate the location of the larynx contraction point. :

[0106] ;

[0107] in, The contraction point of the bonded larynx to the first The distance (along the line connecting the centers of the two pores); For any pair of connected pore nodes and The distance between the centers of the holes For the i-th pore node The corresponding pore radius, For the j-th pore node The corresponding pore radius.

[0108] A bonded throat geometry was constructed based on the contraction point, where the contraction point... It reflects the location of the minimum cross-section between pores.

[0109] Step S5: Calculate the equivalent dimensions of the throat based on the throat geometry;

[0110] Specifically, in this embodiment, the throat geometric model constructed in step S4 is combined with the corresponding pore geometric model to form a complete pore-throat interconnected structure geometric model, such as... Figure 2 As shown, the geometric structure of pores and throats is represented in polygonal form, which clearly reflects the irregular spatial morphology and connectivity of pores and throats in tight reservoirs, and is used to realistically express the spatial connectivity between pores. Furthermore, the cross-sectional area of ​​the reconstructed throat geometry is calculated, and the equivalent scale parameters of the throats are determined based on the principle of area equivalence, which is used to uniformly and quantitatively characterize throats with different geometric shapes.

[0111] Specifically, the geometric data of the pore nodes are first spatially combined with the throat geometry to complete the geometric reconstruction of the pore-throat connection structure.

[0112] Based on the unit direction vector and normal vector from step S4, the geometric boundary vertices of the cylindrical or tangential throat are determined, and the calculation formula is as follows:

[0113] ;

[0114] in, For the i-th pore node The horizontal x-coordinate of the center coordinate (corresponding to the horizontal axis of the 2D plane coordinate system). For the j-th pore node The horizontal x-coordinate of the center coordinate, For the i-th pore node The vertical ordinate of the center coordinate (corresponding to the vertical axis of the 2D plane coordinate system). For the j-th pore node The vertical ordinate of the center coordinate, Let be the component of the throat normal vector along the z-axis (perpendicular to the ordinate). This represents the component of the throat normal vector along the y-axis (perpendicular to the horizontal coordinate). For the i-th pore node The corresponding pore radius.

[0115] A polygonal geometric model of the throat is constructed using four vertices A, B, C, and D to approximate the channel morphology between the pores.

[0116] Calculate the equivalent scale parameters of the throat based on the geometric reconstruction results;

[0117] Specifically, the cross-sectional area of ​​the reconstructed throat geometry is calculated, and the equivalent scale parameters of the throat are determined based on the principle of area equivalence, which are used to uniformly and quantitatively characterize throats with different geometric shapes.

[0118] Calculate the area of ​​any throat geometry. The equivalent radius of the throat was determined based on the principle of area equivalence. :

[0119] ;

[0120] The equivalent radius is used to uniformly characterize the scale features of throats with different geometric shapes, and k is the kth throat.

[0121] Step S6: Based on the throat type and equivalent throat scale, fuse the pore-throat topology network;

[0122] Specifically, the pore-throat topology network is improved by integrating the topological relationships and geometric / scale parameters obtained in the above steps; this step is existing technology and will not be described in detail here. Figure 3 This diagram, which optimizes and constructs a pore connectivity map based on pore connection relationships, uses the overall orientation of the pore connectivity network for fitting and prediction. It uses smooth curves to display more realistic details of pore connectivity, thus intuitively reflecting the overall connectivity characteristics of the pore network and laying the foundation for subsequent microscopic seepage research and experimental simulation.

[0123] Step S7: Based on the fused pore-throat topology network, statistically analyze the connectivity characteristics between pore nodes and reconstruct the pore connectivity structure of the tight reservoir.

[0124] In this specific embodiment, the number of throats connected to each pore is counted, and the connectivity of the pores in the network is characterized in the form of coordination number, thereby reflecting the connectivity characteristics of the tight reservoir pore structure.

[0125] Based on the pore-throat structure that has undergone geometric reconstruction, statistical analysis is performed on the geometric parameters of the pores and throats.

[0126] The aperture radius is directly obtained from the pore geometry, and the throat equivalent radius is... It is obtained from the equivalent calculation based on the geometric cross-sectional area of ​​the throat;

[0127] The number of throats connected to each pore is counted to obtain the pore coordination number distribution, which is used to quantitatively characterize the connectivity features of the pore network.

[0128] Calculate the coordination number of each pore node:

[0129] ;

[0130] in, For the i-th pore node The coordination number, in its core physical meaning, is the number of throats connected to a single pore (i.e., the number of other pores directly connected to that pore). A binary indicator variable (taking only 0 or 1) used to determine the i-th pore node. With the j-th pore node Does a connectivity relationship exist? j is the index of the pore node, corresponding to i, used to traverse all pore nodes and determine its connection to the i-th pore node. The connectivity relationship is denoted by , and the value ranges from 1 to n; n is the total number of pore nodes.

[0131] Indicates pore size With pores There is a connection. This indicates the absence of connectivity, thus characterizing the connectivity features of the pore network using the coordination number distribution.

[0132] The pore size parameters, throat equivalent size parameters, and pore coordination number are output in tabular form for use in digital core structure analysis of tight reservoirs and subsequent microscopic numerical simulations.

[0133] This application enables automatic identification and geometric reconstruction of pore-throat structures directly based on digital core pore data without introducing additional geometric assumptions, and completes the quantitative calculation of pore connectivity characteristics and throat scale parameters, providing a reliable structural basis for tight reservoir pore structure analysis and subsequent numerical simulation studies.

[0134] To help those skilled in the art better understand this embodiment, the relevant experimental simulation diagrams are as follows:

[0135] Figure 4 A pore radius distribution map is shown. By statistically analyzing the radii of all pores in the digital core, the frequency distribution characteristics of the pore radius are obtained, which reflects the heterogeneity of the pore scale in tight reservoirs.

[0136] Figure 5 The distribution map of the equivalent radius of the throat is shown. The equivalent radius of the throat is obtained by performing equivalent calculations on the reconstructed throat geometry, and is used to uniformly characterize the scale features of throats with different geometric shapes.

[0137] Figure 6 The diagram shows the coordination number distribution of pores. The coordination number represents the number of throats connected to a single pore. By statistically analyzing the coordination number distribution, the connectivity and spatial differences of pore networks can be quantitatively characterized.

[0138] Example 2

[0139] This embodiment provides a geometric reconstruction device for the micropore connectivity network of tight reservoir rocks, used to implement the geometric reconstruction method for the micropore connectivity network of tight reservoir rocks described in Embodiment 1, including:

[0140] The pore geometry data acquisition module is used to acquire the geometric data of each pore node in the target reservoir core and construct a pore node set, wherein the pore node includes the pore center coordinates and pore radius;

[0141] The topology network establishment module is used to establish a pore-throat topology network based on the connection relationship between pore nodes in the pore node set;

[0142] The throat discrimination module is used to calculate the center-to-center distance between pore nodes based on the spatial relationship between connected pore nodes in the pore node set, and to determine the throat type based on the center-to-center distance between pore nodes.

[0143] The throat geometry construction module is used to construct the corresponding throat geometry for different throat types;

[0144] An equivalent scale calculation module is used to calculate the equivalent scale of the throat based on the throat geometry.

[0145] The network fusion module is used to fuse pore-throat topology networks based on throat type and throat equivalent scale.

[0146] The connectivity structure reconstruction module is used to reconstruct the pore connectivity structure of tight reservoirs based on the fused pore-throat topology network, statistically analyze the connectivity characteristics between pore nodes, and reconstruct the pore connectivity structure of tight reservoirs.

[0147] This embodiment has the same technical features as the geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks provided in Embodiment 1, so it can also solve the same technical problems and achieve the same technical effects.

[0148] Example 3

[0149] This embodiment provides a computer storage medium storing a computer program that, when executed by a processor, implements the geometric reconstruction method for the interconnected micropore network of tight reservoir rocks as described in Embodiment 1.

[0150] The aforementioned storage media include: flash memory, hard disk, multimedia card, card-type memory (e.g., SD (Secure Digital Memory Card) or DX (Memory Data Register, MDR) memory), random access memory (RAM), static random-access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic storage, disk, optical disk, server, APP (Application) application store, and other media capable of storing program verification codes, on which computer programs are stored. When the computer programs are executed by the processor, they can implement the various steps of the geometric reconstruction method for the micropore connectivity network of tight reservoir rocks described above.

[0151] As can be seen from the above embodiments, the method provided in this application can directly realize the automatic reconstruction of pore-throat connectivity structure based on digital core data without introducing regular geometric assumptions, and complete the quantitative statistics of pore scale and connectivity characteristics.

[0152] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in this application, or make equivalent substitutions for some of the technical features. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application.

[0153] The applicant has provided a detailed description of the implementation examples of this application in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above implementation examples are merely preferred embodiments of this application. The detailed description is only intended to help readers better understand the spirit of this application and is not intended to limit the scope of protection of this application. On the contrary, any improvements or modifications made based on the inventive spirit of this application should fall within the scope of protection of this application.

Claims

1. A method for geometrically reconstructing the microscopic pore connectivity network of tight reservoir rocks, characterized in that, include: Obtain the geometric data of each pore node in the core of the target reservoir, and construct a set of pore nodes, wherein the pore nodes include the coordinates of the pore center and the pore radius; Based on the connection relationships between pore nodes in the pore node set, a pore-throat topology network is established; Based on the spatial relationship between connected pore nodes in the pore node set, the center-to-center distance between pore nodes is calculated, and the throat type is determined according to the center-to-center distance between pore nodes. For different throat types, construct corresponding throat geometry; Calculate the equivalent dimensions of the throat based on the described throat geometry; Based on the throat type and throat equivalent scale, a pore-throat topology network is fused. Based on the fused pore-throat topology network, the connectivity characteristics between pore nodes are statistically analyzed to reconstruct the pore connectivity structure of tight reservoirs.

2. The geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks according to claim 1, characterized in that, The method of determining the throat type based on the center-to-center distance between pore nodes includes: When the center-to-center distance of the pores is greater than the sum of the radii of the two pores, it is determined to be a bonded throat. When the center-to-center distance of the pores is greater than the difference between the radii of the two pores but less than the sum of the radii of the two pores, it is determined to be a cylindrical throat. When the center distance between two pores is less than the difference in their radii, it is determined to be a merged pore structure. When the center-to-center distance between the two pores is equal to the sum of their radii or the difference between their radii, it is determined to be a tangential throat.

3. The geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks according to claim 2, characterized in that, Also includes: For the cylindrical throat or the tangential throat, the main extension direction of the throat is determined by calculating the unit direction vector of the line connecting the centers of any pair of connected pore nodes.

4. The geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks according to claim 3, characterized in that, Also includes: The position of the lateral boundary of the throat geometry is determined by calculating the normal vector perpendicular to the unit direction vector. Based on the unit direction vector and the normal vector, the polygonal geometric boundary vertices of the cylindrical throat or the tangent throat are determined.

5. The geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks according to claim 4, characterized in that, The polygonal geometric boundary vertices of the cylindrical throat or tangent throat are determined based on the unit direction vector and the normal vector, and the calculation formula is as follows: ； in, For the i-th pore node The horizontal x-coordinate of the center coordinate, For the j-th pore node The horizontal x-coordinate of the center coordinate, For the i-th pore node The vertical ordinate of the center coordinate, For the j-th pore node The vertical ordinate of the center coordinate, Let be the component of the throat normal vector along the z-axis. Let be the component of the throat normal vector along the y-axis. For the i-th pore node The corresponding pore radius, For the j-th pore node The corresponding pore radius.

6. The geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks according to claim 2, characterized in that, Also includes: For the bonded throat, the geometry of the bonded throat is constructed by determining the location of the contraction point. The expression for calculating the location of the contraction point is as follows: ； in, The contraction point of the bonded larynx to the first The distance; Connected pore nodes and The distance between the centers of the holes For the i-th pore node The corresponding pore radius, For the j-th pore node The corresponding pore radius.

7. The geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks according to claim 1, characterized in that, The calculation of the equivalent dimensions of the throat based on the throat geometry includes: Calculate the geometric area of ​​any throat. ; Based on the area of ​​the geometric body Based on the principle of area equivalence, the equivalent radius of the throat is determined by the following formula: ； in, The area of ​​the geometric solid is The equivalent radius of the larynx is used to characterize the equivalent scale of the larynx; k is the kth larynx.

8. The geometric reconstruction method for the microscopic pore connectivity network of tight reservoir rocks according to claim 1, characterized in that, The statistical analysis of inter-pore node connectivity characteristics, and the reconstruction of tight reservoir pore connectivity structure, includes completing the coordination number distribution by statistically analyzing the coordination number of each pore node, and reconstructing the tight reservoir pore connectivity structure based on the coordination number distribution. The formula for calculating the coordination number of each pore node is as follows: ； in, For the i-th pore node The coordination number represents the number of throats connected to a single pore node; It is a binary indicator variable used to determine the i-th pore node. With the j-th pore node Does a connectivity relationship exist? j is the index of the pore node, ranging from 1 to n; n is the total number of pore nodes.

9. A computer storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the geometric reconstruction method for the micropore connectivity network of tight reservoir rocks as described in any one of claims 1 to 8.

Images