Reef limestone voxel dynamic merging modeling method and system based on digital core

Abstract

The invention discloses a digital core-based reef limestone voxel dynamic merging modeling method and system, and the method comprises the steps: carrying out the CT scanning of reef limestone, and obtaining a rock mass section gray image; carrying out image processing on the rock mass section grayscale image to obtain a binary image; establishing a three-dimensional digital core model of a rock microstructure according to the binarized image; calculating a representative volume unit size according to the three-dimensional digital core model; performing dynamic combination on the spatially continuous minimum homoplastid in the three-dimensional digital core model to obtain a voxel combination result; and modeling according to the representative body unit size and the voxel merging result to obtain a reef limestone three-dimensional pore and matrix numerical model. According to the embodiment of the invention, the number of units and nodes of the model can be reduced in the modeling process, the established finite element model not only can truly reflect the pore structure characteristics of the reef limestone, but also can remarkably improve the calculation efficiency and the modeling precision, and can be widely applied to the technical field of computers.

Description

Technical Field

[0001] The present application relates to the field of computer technology, and in particular to a method and system for dynamically merging reef limestone voxels based on digital cores. Background Art

[0002] Reef limestone is the foundation of island and reef engineering construction. Fully understanding the physical and mechanical properties of coral reef limestone is one of the important prerequisites for carrying out island and reef engineering construction. During the diagenesis of coral reef limestone, the biological characteristics of the internal native coral skeleton are retained, so there are common characteristics such as structural, heterogeneous and high porosity. The complex mesoscopic pore structure of reef limestone has a significant impact on its macroscopic mechanical properties. Therefore, the reconstruction of the mesoscopic pore structure of reef limestone provides a solid foundation for the numerical simulation of the basic physical properties of reef limestone.

[0003] The existing technology is used to carry out 3D modeling of reef limestone. The number of units and nodes in the established model is huge, and the computer memory requirements are very high when performing analysis and calculation. Although the compressed row storage (CSR) format is used to store data, the memory required for calculation is also very large. If high-performance computing and parallel solvers are used forcibly, processing such large-scale data will still face problems of computational efficiency and numerical stability, making digital core modeling infeasible in practical applications. Summary of the invention

[0004] In order to solve at least one of the above problems, the embodiments of the present application propose a digital core-based reef limestone voxel dynamic merging modeling method and system with high computational efficiency and good numerical stability.

[0005] To achieve the above-mentioned purpose, one aspect of an embodiment of the present application proposes a method for dynamic merging modeling of reef limestone voxels based on digital cores, the method comprising:

[0006] The reef limestone is CT scanned to obtain a grayscale image of the rock mass profile;

[0007] Performing image processing on the rock mass profile grayscale image to obtain a binary image;

[0008] Establishing a three-dimensional digital core model of the rock mesostructure according to the binary image;

[0009] Calculating representative volume unit size based on the three-dimensional digital core model;

[0010] Dynamically merging spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result;

[0011] Modeling is performed according to the representative volume unit size and the voxel merging result to obtain a three-dimensional pore and matrix numerical model of reef limestone.

[0012] In some embodiments, establishing a three-dimensional digital core model of the rock mesostructure according to the binary image comprises the following steps:

[0013] Extracting the pore structure of the reef limestone and the spatial network characteristics of the rock matrix from the binary image;

[0014] Determining the pore structure and rock matrix spatial network of the reef limestone according to the spatial network characteristics;

[0015] A volume rendering model is used to establish a three-dimensional digital core model of the rock microstructure according to the spatial network.

[0016] In some embodiments, the calculating the representative volume unit size according to the three-dimensional digital core model comprises the following steps:

[0017] According to the three-dimensional digital core model, the fractal dimension of the reef limestone block is calculated by using a box counting method;

[0018] When the variation range of the fractal dimension is within a preset measurement error range, the current size of the reef limestone block is determined as the representative volume unit size.

[0019] In some embodiments, dynamically merging the spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result comprises the following steps:

[0020] Create an array of merged voxel numbers;

[0021] Arrange the voxels in the merged voxel size merged voxel quantity array according to the index priority based on the maximum voxel quantity index values ​​in the x direction, the y direction and the z direction;

[0022] Determine the current number of merged voxels from the merged voxel number array;

[0023] Initialize the maximum index value of the current voxel unit to the current voxel index value;

[0024] When all voxels corresponding to the combined voxel number meet a preset condition, the combined voxel number is added to the current voxel index value, and homogeneous voxels are expanded to obtain a homogeneous voxel block;

[0025] The unit node coordinates are calculated according to the largest homogeneous voxel block to obtain the voxel merging result.

[0026] In some embodiments, the preset conditions include:

[0027] The voxels in the current merged voxel number correspondence do not exceed the boundary of the merged voxel number array;

[0028] All voxels corresponding to the current number of merged voxels have the same value as the current voxel unit;

[0029] All voxels corresponding to the current number of merged voxels have not been visited.

[0030] In some embodiments, the modeling is performed according to the representative volume unit size and the voxel merging result to obtain a three-dimensional pore and matrix numerical model of reef limestone, comprising the following steps:

[0031] converting each homogeneous voxel block in the voxel merging result into a finite element unit;

[0032] A three-dimensional pore and matrix numerical model of reef limestone is established based on the representative volume unit size and the finite element unit.

[0033] In some embodiments, converting each homogeneous voxel block in the voxel merging result into a finite element unit comprises the following steps:

[0034] Determine the actual physical space coordinates of each vertex coordinate of the target voxel unit according to the position of the target voxel unit in the homogeneous voxel block in the three-dimensional voxel array;

[0035] The unit node coordinates of the target voxel unit are calculated according to the actual physical space coordinates, the size of the largest homogeneous voxel block and the scaling factor.

[0036] To achieve the above purpose, another aspect of the embodiment of the present application provides a digital core-based reef limestone voxel dynamic merging modeling system, the system comprising:

[0037] The first module is used to perform CT scanning on the reef limestone to obtain a grayscale image of the rock mass profile;

[0038] The second module is used to perform image processing on the grayscale image of the rock mass profile to obtain a binary image;

[0039] The third module is used to establish a three-dimensional digital core model of the rock mesostructure based on the binary image;

[0040] A fourth module is used to calculate the representative volume unit size according to the three-dimensional digital core model;

[0041] A fifth module is used to dynamically merge spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result;

[0042] The sixth module is used to perform modeling based on the representative volume unit size and the voxel merging result to obtain a three-dimensional pore and matrix numerical model of reef limestone.

[0043] To achieve the above-mentioned purpose, another aspect of an embodiment of the present application provides an electronic device, the electronic device comprising a memory and a processor, the memory storing a computer program, and the processor implementing the above-mentioned method when executing the computer program.

[0044] To achieve the above objective, another aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0045] The embodiments of the present application include at least the following beneficial effects: the present application provides a method and system for dynamic merging voxels of reef limestone based on digital cores, the scheme obtains a grayscale image of a rock profile by performing CT scanning on the reef limestone; performs image processing on the grayscale image of the rock profile to obtain a binary image; establishes a three-dimensional digital core model of the rock mesostructure based on the binary image; calculates the representative volume unit size based on the three-dimensional digital core model; dynamically merges the spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result; performs modeling based on the representative volume unit size and the voxel merging result to obtain an overall scheme of a three-dimensional pore and matrix numerical model of the reef limestone, which can reduce the number of units and nodes of the model during the modeling process, and the established finite element model can not only truly reflect the pore structure characteristics of the reef limestone, but also significantly improve the calculation efficiency and modeling accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are used to provide further understanding of the technical solution 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 solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0047] Figure 1 It is a step diagram of a method for dynamic merging modeling of reef limestone voxels based on digital cores provided in an embodiment of the present application;

[0048] Figure 2 It is a flow chart of a method for dynamic merging and modeling of reef limestone voxels based on digital cores provided in an embodiment of the present application;

[0049] Figure 3 is a schematic diagram of fractal dimensions of type I reef limestone with different RVE sizes provided in an embodiment of the present application;

[0050] Figure 4 is a schematic diagram of fractal dimensions of type II reef limestone with different RVE sizes provided in an embodiment of the present application;

[0051] Figure 5 is a schematic diagram of an RVE image of type I reef limestone provided in an embodiment of the present application;

[0052] Figure 6 It is a schematic diagram of a finite element model modeled by the OVOE method provided in an embodiment of the present application;

[0053] Figure 7 It is a schematic diagram of a finite element model modeled by the DVBA method provided in an embodiment of the present application;

[0054] Figure 8 It is a schematic diagram of local details of a finite element model modeled by the OVOE method provided in an embodiment of the present application;

[0055] Fig. 9 It is a schematic diagram of local details of a finite element model modeled by the DVBA method provided in an embodiment of the present application;

[0056] Fig.10 It is a module schematic diagram of a digital core-based reef limestone voxel dynamic merging modeling system provided in an embodiment of the present application;

[0057] Fig.11 It is a schematic diagram of the hardware structure of the electronic device provided in the embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are only examples of devices and methods consistent with some aspects of the embodiments of the present application as detailed in the attached claims.

[0059] Although the functional modules are divided in the system schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms "first / S100", "second / S200", etc. in the specification, claims and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0060] It is understood that the terms "first", "second", etc. used in this application can be used to describe various concepts in this article, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another concept. For example, without departing from the scope of the embodiment of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein can be interpreted as "at the time of" or "when" or "in response to determination".

[0061] The terms "at least one", "multiple", "each", "any", etc. used in this application, at least one includes one, two or more, multiple includes two or more, each refers to each of the corresponding multiple, and any refers to any one of the multiple.

[0062] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0064] In the related art, the existing technology is used to perform three-dimensional modeling of reef limestone. The number of units and nodes in the established model is huge, and the computer memory requirements are very high when performing analysis and calculation. Although the compressed row storage (CSR) format is used to store data, the memory required for calculation is also very large. If high-performance computing and parallel solvers are forcibly used, processing such large-scale data will still face problems of computational efficiency and numerical stability, making digital core modeling infeasible in practical applications.

[0065] In view of this, a method and system for modeling reef limestone voxels dynamically merged based on digital cores is provided in the embodiment of the present application. The scheme reduces the number of generated units and nodes while ensuring modeling accuracy by optimizing the representative unit size of the rock mass and the dynamic merging of voxels, thereby improving computational efficiency. In addition, the unit size of the established finite element model will gradually decrease when the homogeneous voxel region transitions to the non-homogeneous voxel region, realizing a progressive local mesh refinement, which can better simulate local effects such as stress concentration and high deformation gradient.

[0066] The embodiment of the present application provides a method for dynamic merging and modeling of reef limestone voxels based on digital cores, which relates to the field of computer technology. The embodiment of the present application provides a method for dynamic merging and modeling of reef limestone voxels based on digital cores, which can be applied to terminals, servers, or software running in terminals or servers. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, a smart speaker, a smart watch, and a car terminal, etc., but is not limited to this; the server side can be configured as an independent physical server, or a server cluster or distributed system composed of multiple physical servers, and can also be configured as a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network; the software can be an application that implements a method for dynamic merging and modeling of reef limestone voxels based on digital cores, etc., but is not limited to the above forms.

[0067] The present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments, in which tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0068] Figure 1 is an optional flow chart of a method for dynamic merging modeling of reef limestone voxels based on digital cores provided in an embodiment of the present application. Figure 1 The method may include but is not limited to steps S100 to S600.

[0069] Step S100, performing CT scanning on the reef limestone to obtain a grayscale image of the rock mass profile;

[0070] Step S200, performing image processing on the grayscale image of the rock mass profile to obtain a binary image.

[0071] Step S300: establishing a three-dimensional digital core model of the rock mesostructure based on the binary image.

[0072] Step S400: Calculate the size of a representative volume unit according to the three-dimensional digital core model.

[0073] Step S500: dynamically merge spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result.

[0074] Step S600, modeling is performed according to the representative volume unit size and the voxel merging result to obtain a three-dimensional pore and matrix numerical model of the reef limestone.

[0075] Steps S100 to S600 shown in the embodiment of the present application can reduce the number of units and nodes of the model during the modeling process, thereby improving computing efficiency and modeling accuracy.

[0076] In some embodiments, step S300 may include but is not limited to the following steps S310 to S330:

[0077] Step S310, extracting the pore structure of the reef limestone and the spatial network characteristics of the rock matrix from the binary image;

[0078] Step S320, determining the pore structure and rock matrix spatial network of the reef limestone according to the spatial network characteristics;

[0079] Step S330: using a volume rendering model, a three-dimensional digital core model of the rock microstructure is established according to the spatial network.

[0080] In some embodiments, step S400 may include but is not limited to the following steps S410 to S420:

[0081] Step S410, calculating the fractal dimension of the reef limestone block by using a box counting method according to the three-dimensional digital core model;

[0082] Step S420: When the variation range of the fractal dimension is within a preset measurement error range, the current size of the reef limestone block is determined as the representative volume unit size.

[0083] In some embodiments, step S500 may include but is not limited to the following steps S510 to S560:

[0084] Step S510, creating a merged voxel number array;

[0085] Step S520, arranging the voxels in the merged voxel number array according to the index priority based on the maximum voxel number index values ​​in the x direction, the y direction and the z direction;

[0086] Step S530, determining the current number of merged voxels from the merged voxel number array;

[0087] Step S540, initializing the maximum index value of the current voxel unit as the current voxel index value;

[0088] Step S550, when all voxels in the combined voxel number meet the preset condition, the combined voxel number is added to the current voxel index value, and homogeneous voxels are expanded to obtain a homogeneous voxel block;

[0089] Step S560, calculating unit node coordinates according to the largest homogeneous voxel block to obtain a voxel merging result.

[0090] In step S550 of some embodiments, the preset condition includes:

[0091] The voxels corresponding to the current number of merged voxels do not exceed the boundary of the array of the number of merged voxels;

[0092] All voxels corresponding to the current number of merged voxels have the same value as the current voxel unit;

[0093] All voxels corresponding to the current number of merged voxels have not been visited.

[0094] In some embodiments, step 600 includes but is not limited to the following steps S610-S620:

[0095] Step S610, converting each homogeneous voxel block in the voxel merging result into a finite element unit;

[0096] Step S620: establishing a three-dimensional pore and matrix numerical model of reef limestone according to the representative volume unit size and the finite element unit.

[0097] In some embodiments, step S610 further includes the following steps S611-S612:

[0098] Step S611, determining the actual physical space coordinates of each vertex coordinate of the target voxel unit according to the position of the target voxel unit in the homogeneous voxel block in the three-dimensional voxel array;

[0099] Step S612: Calculate the unit node coordinates of the target voxel unit according to the actual physical space coordinates, the size of the largest homogeneous voxel block and the scaling factor.

[0100] Below, in conjunction with the accompanying drawings and specific application examples, the scheme of the embodiment of the present application is described in detail and explained:

[0101] In the embodiment of the present application, a method for dynamic merging modeling of reef limestone voxels based on digital core is provided, which can be applied to high-precision three-dimensional modeling of reef limestone. Figure 2 The method can be realized through the steps of CT scanning, image processing, reconstruction of digital core, calculation of representative volume unit size of reef limestone, and establishment of three-dimensional model. The specific introduction of each step is as follows:

[0102] (1) CT scan.

[0103] First, the reef limestone is cut and processed into a CT scanning standard sample, and then the reef limestone sample is scanned using a CT scanner. The different structures (rock matrix and pores) inside the reef limestone are distinguished by using the difference in the X-ray absorption ability of media with different densities. Through continuous scanning, x×y×z continuous profile grayscale images of the rock mass are obtained.

[0104] For example, the reef limestone sample can be taken from the shallow area of ​​the island reef, which is white in color, rough in surface, porous and brittle. A cylindrical sample with a diameter of Ф=50mm and a height of h=25mm is drilled from the original reef limestone rock, and the two ends are cut flat before a CT scanning test is performed. The CT resolution is 31.25um. After the sample is scanned layer by layer, 800 CT image slices are obtained, and the pixel size of each slice is 1600×1600.

[0105] (2) Image processing.

[0106] The original grayscale images obtained after CT scanning have serious noise and artifacts. If they are not processed, the quality of the grayscale images will be affected, and then the accuracy of subsequent modeling will be affected. Python software was used to preprocess the CT scan images, including grayscale value optimization, noise reduction and threshold segmentation. In order to further distinguish the rock matrix and pores in the transition area, the grayscale value was optimized first, and the grayscale value range of each CT image was adjusted from the original 0 to 255 to the grayscale value range of the transition area. Then the median filtering method was used to remove the ring artifacts and impulse noise in the image. The median filtering method considers the N_p pixel values ​​of the neighborhood around each pixel point, sorts the pixel values ​​in the neighborhood and selects the median as the new pixel value. Finally, the adaptive threshold segmentation method is used to deal with the problems of image ring artifacts and uneven brightness and perform image binarization. The principle of this method is to use the mean or median of the grayscale value in the pixel neighborhood N_p as the threshold of the central pixel. If the grayscale value of the pixel is greater than the threshold, the pixel is white (rock matrix) in the output image, otherwise it is output as black (rock pore).

[0107] For example, Python software was used to preprocess the CT scan images, including grayscale optimization, noise reduction, and threshold segmentation. In order to further distinguish the rock matrix and pores in the transition area, grayscale optimization was first performed, and the grayscale value range of each CT image was adjusted from the original 0 to 255 to the grayscale value range of the transition area. Then the median filtering method was used to remove the ring artifacts and impulse noise in the image. Finally, the adaptive threshold segmentation method was used to deal with the problems of image ring artifacts and uneven brightness and to perform image binarization to distinguish the rock matrix and pores of the reef limestone.

[0108] (3) Reconstruction of digital core.

[0109] Based on the grayscale value optimization, noise reduction and threshold segmentation of the grayscale image, the spatial network characteristics of the pore structure and rock matrix are extracted respectively, and the spatial network of the pore structure and rock matrix is ​​obtained by calculation. The volume rendering model is used to establish a three-dimensional digital core model of the rock microstructure.

[0110] (4) Calculation of representative volume unit size of reef limestone.

[0111] In order to ensure that the simulation results of the mesostructure of reef limestone can accurately reflect its macroscopic properties, it is necessary to conduct multi-scale analysis reasonably to avoid the boundary effect caused by the small size of REV (representative volume element), which causes the model to only reflect the local details of the rock mass rather than the overall average behavior. At the same time, if the size of REV is too large, more units and nodes will be required to establish the model, which will affect the calculation efficiency. Considering the requirements for both model accuracy and calculation efficiency, it is necessary to reasonably determine the size of RVE. The pore structure of reef limestone is usually anisotropic and self-similar, and the fractal geometry theory can quantitatively characterize the irregularity and self-similarity of the rock mass pores. Therefore, the box dimension method is used to calculate the fractal dimension f of reef limestone blocks (cubes) of different sizes. r If the specific value of the fractal dimension no longer changes significantly, or the range of change is very small, it can be considered to fluctuate within the measurement error range. Then it can be judged that the fractal dimension gradually converges to a stable state. The size corresponding to the fractal dimension gradually converging to a stable state is the REV size.

[0112] For example, the box dimension method is used to calculate the fractal dimension f of reef limestone blocks (cubes) of different sizes. r The size corresponding to the fractal dimension that gradually converges and tends to be stable is selected as the REV size. The fractal dimensions of type I reef limestone with different RVE sizes are as follows: Figure 3 As shown in Figure 2, the fractal dimensions of type II reef limestone with different RVE sizes are as follows: Figure 4 As shown. Figure 3 and Figure 4It can be seen that with the increase of the size of the representative volume element (RVE), the fractal dimensions of the two types of reef limestones show a characteristic of gradually converging and stabilizing. By comparison, the fractal dimension of type I reef limestone stabilizes at 2.83 after the RVE size exceeds 0.60 cm. The fractal dimension of type II reef limestone stabilizes at 2.85 after the RVE size exceeds 1.60 cm. The minimum RVE size (L0) and the maximum pore radius (r min ) is about 10. Therefore, the representative unit sizes of type I and type II reef limestone are 0.60 cm and 1.60 cm, respectively.

[0113] (5) Dynamic voxel merging.

[0114] The spatially continuous homogeneous voxels are merged into a larger voxel block to generate the corresponding finite element unit, thereby reducing the number of units and nodes in the finite element model. The basic process of the dynamic voxel merging (DVBA) method is as follows:

[0115] First, define the merged voxel number array v size , can be arranged from largest to smallest according to index priority:

[0116]

[0117] In the formula, l max , w max ,h max The index values ​​of the maximum number of voxels in the corresponding x, y, and z directions are respectively In some embodiments, they are also arranged from small to large according to the index priority.

[0118] Secondly, for any v i (i i ,j i ,k i ), initialize its maximum index (l max ,w max ,h max ) is the index of the current voxel (l i ,w i ,h i ). If and only if v size When all corresponding voxels meet the following three conditions:

[0119] ① Current v size The corresponding voxel does not exceed the boundary of the voxel array;

[0120] ② Current v size All voxels corresponding to v i (i i ,j i ,k i ) have the same value;

[0121] ③ Current v size All corresponding voxels were not visited before voxel merging;

[0122] Then the current v size Add to (l i ,w i ,h i ) and expand the number of homogeneous voxels. Otherwise, adjust (l i -1,w i -1,h i -1) is the current maximum index, and the above steps are repeated until the minimum number of homogeneous voxels is obtained.

[0123] (6) Model establishment. For any voxel unit v i， Its position in the three-dimensional voxel array is (i i ,j i ,k i ), considering that each vertex of the voxel (dx i ,dy i ,dz i ) can be obtained by adding 0 or 1 in three dimensions, then v i The relative positions of the vertices are as follows:

[0124]

[0125] The corresponding unit node coordinates are calculated according to the size of the largest homogeneous voxel block, that is:

[0126] x i =(x vi +d xi l i )×s x ;

[0127] y i =(y vi +d yi w i )×s y ;

[0128] z i =(z vi +d zi h i )×s z ;

[0129] In the formula, x vi ,y vi 、z vi is the position coordinate of the voxel in the voxel space; x i ,y i 、z iis the position coordinate of the voxel in the actual physical space; s x 、s y 、s z v i The scaling factor used to convert coordinates from voxel space to actual physical space.

[0130] Based on the above operations, one voxel unit can be converted into a finite element unit (one volex to one element, OVOE), combined with the determined REV size, to establish a high-precision three-dimensional pore-matrix numerical model of reef limestone.

[0131] For example, Figures 5 to 9 This is the RVE digital core model of type I reef limestone and its corresponding finite element model, where the maximum index of the voxel block in the DVBA method is (5,5,5). Figure 5 Schematic diagram of RVE of Type I reef limestone. Figure 6 , Figure 7 ,The finite element model established by the DVBA method has 1442373 nodes, which is 89.70% less than that of the OVOE method, that is, the memory required for simulation is reduced by 89.70%. Figure 8 , Fig. 9 The figure shows the unit division details of the finite element model at z = 0.3 cm in the xy plane. Figure 8 , Fig. 9 The local details of the pore-matrix of the reef limestone depicted by the finite element model established by the DVBA method are consistent with those of the OVOE method, and the microstructure of the reef limestone sample is well preserved.

[0132] Based on the above method, in the process of converting the digital core model into the FEM model, the unit size is dynamically adjusted according to the continuity of the voxel spatial distribution to form a homogeneous block as large as possible, and each block is converted into a separate finite element unit, which can reduce the number of generated units and nodes and improve the calculation efficiency. size The homogeneous voxel blocks are indexed step by step with size as the priority. The unit size of the established finite element model will gradually decrease when the homogeneous voxel area transitions to the non-homogeneous voxel area, realizing a progressive local mesh refinement, which can better simulate local effects such as stress concentration and high deformation gradient.

[0133] In summary, the embodiments of the present application have at least the following beneficial effects:

[0134] 1. In the process of converting the digital core model into the FEM model, the unit size is dynamically adjusted according to the continuity of the voxel spatial distribution to form a homogeneous block as large as possible, which can reduce the number of generated units and nodes and significantly improve the modeling accuracy and calculation efficiency.

[0135] 2. The homogeneous voxel blocks are indexed step by step according to the priority of voxel size. The unit size of the established finite element model will gradually decrease when the homogeneous voxel area transitions to the non-homogeneous voxel area, realizing a progressive local mesh refinement, which can better simulate local effects such as stress concentration and high deformation gradient.

[0136] 3. By calculating the REV size and the voxel dynamic merging method, the requirements of computational efficiency and modeling accuracy are comprehensively considered and the mutual constraints between the two are solved. The established finite element model can not only truly reflect the pore structure characteristics of reef limestone, but also significantly improve the computational efficiency.

[0137] See also Fig.10 The embodiment of the present application also provides a digital core-based reef limestone voxel dynamic merging modeling system, which can implement the above-mentioned digital core-based reef limestone voxel dynamic merging modeling method, and the system includes:

[0138] The first module 101 is used to perform CT scanning on the reef limestone to obtain a grayscale image of the rock mass profile;

[0139] The second module 102 is used to perform image processing on the rock mass profile grayscale image to obtain a binary image;

[0140] The third module 103 is used to establish a three-dimensional digital core model of the rock mesostructure according to the binary image;

[0141] The fourth module 104 is used to calculate the representative volume unit size according to the three-dimensional digital core model;

[0142] The fifth module 105 is used to dynamically merge the spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result;

[0143] The sixth module 106 is used to perform modeling based on the representative volume unit size and the voxel merging result to obtain a three-dimensional pore and matrix numerical model of the reef limestone.

[0144] It can be understood that the contents of the above method embodiments are all applicable to the present system embodiments, the functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0145] The embodiment of the present application also provides an electronic device, the electronic device includes a memory and a processor, the memory stores a computer program, and the processor implements the above-mentioned digital core-based reef limestone voxel dynamic merging modeling method when executing the computer program. The electronic device can be any intelligent terminal including a tablet computer, a car computer, etc.

[0146] It can be understood that the contents of the above method embodiments are all applicable to the present device embodiments, the functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0147] See also Fig.11 , Fig.11 The hardware structure of an electronic device of another embodiment is illustrated, and the electronic device includes:

[0148] The processor 201 may be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application;

[0149] The memory 202 can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 202 can store an operating system and other application programs. When the technical solution provided in the embodiment of this specification is implemented by software or firmware, the relevant program code is stored in the memory 202, and the processor 201 calls and executes a method for dynamic merging modeling of reef limestone voxels based on digital cores in the embodiment of this application;

[0150] Input / output interface 203, used to implement information input and output;

[0151] The communication interface 204 is used to realize the communication interaction between the device and other devices. The communication can be realized through a wired manner (such as USB, network cable, etc.) or a wireless manner (such as mobile network, WIFI, Bluetooth, etc.);

[0152] Bus 205 , which transmits information between various components of the device (e.g., processor 201 , memory 202 , input / output interface 203 , and communication interface 204 );

[0153] The processor 201 , the memory 202 , the input / output interface 203 and the communication interface 204 are connected to each other in communication within the device via the bus 205 .

[0154] An embodiment of the present application also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above-mentioned digital core-based reef limestone voxel dynamic merging modeling method is implemented.

[0155] It can be understood that the contents of the above method embodiments are all applicable to the present storage medium embodiments, the functions specifically implemented by the present storage medium embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0156] The memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely disposed relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0157] The embodiments described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0158] Those skilled in the art will appreciate that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0159] The system embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0160] Those skilled in the art will appreciate that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices may be implemented as software, firmware, hardware, or a suitable combination thereof.

[0161] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0162] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0163] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the system embodiments described above are only schematic. For example, the division of the above units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0164] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0165] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0166] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including multiple instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, referred to as ROM), random access memory (Random Access Memory, referred to as RAM), disk or optical disk and other media that can store programs.

[0167] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A method for dynamic merging modeling of reef limestone voxels based on digital cores, characterized in that: The following steps are involved: The reef limestone is CT scanned to obtain a grayscale image of the rock mass profile; Performing image processing on the rock mass profile grayscale image to obtain a binary image; Establishing a three-dimensional digital core model of the rock mesostructure according to the binary image; Calculating representative volume unit size based on the three-dimensional digital core model; Dynamically merging spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result; Modeling is performed according to the representative volume unit size and the voxel merging result to obtain a three-dimensional pore and matrix numerical model of reef limestone.

2. The method according to claim 1, characterized in that The method of establishing a three-dimensional digital core model of the rock mesostructure according to the binary image comprises the following steps: Extracting the pore structure of the reef limestone and the spatial network characteristics of the rock matrix from the binary image; Determining the pore structure and rock matrix spatial network of the reef limestone according to the spatial network characteristics; A volume rendering model is used to establish a three-dimensional digital core model of the rock microstructure according to the spatial network.

3. The method according to claim 1, characterized in that The step of calculating the representative volume unit size according to the three-dimensional digital core model comprises the following steps: According to the three-dimensional digital core model, the fractal dimension of the reef limestone block is calculated by using the box dimension counting method; When the variation range of the fractal dimension is within a preset measurement error range, the current size of the reef limestone block is determined as the representative volume unit size.

4. The method according to claim 1, characterized in that: The step of dynamically merging the spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result comprises the following steps: Create an array of merged voxel numbers; Arranging the voxels in the merged voxel number array according to the index priority based on the maximum voxel number index values ​​in the x-direction, the y-direction, and the z-direction; Determine the current number of merged voxels from the merged voxel number array; Initialize the maximum index value of the current voxel unit to the current voxel index value; When all voxels corresponding to the combined voxel number meet a preset condition, the combined voxel number is added to the current voxel index value, and homogeneous voxels are expanded to obtain a homogeneous voxel block; The unit node coordinates are calculated according to the largest homogeneous voxel block to obtain the voxel merging result.

5. The method according to claim 4, characterized in that The preset conditions include: The voxels corresponding to the current number of merged voxels do not exceed the boundary of the array of the number of merged voxels; All voxels corresponding to the current number of merged voxels have the same value as the current voxel unit; All voxels corresponding to the current number of merged voxels have not been visited.

6. The method according to claim 1, characterized in that The method of modeling according to the representative volume unit size and the voxel merging result to obtain a three-dimensional pore and matrix numerical model of reef limestone includes the following steps: converting each homogeneous voxel block in the voxel merging result into a finite element unit; A three-dimensional pore and matrix numerical model of reef limestone is established based on the representative volume unit size and the finite element unit.

7. The method according to claim 6, characterized in that The step of converting each homogeneous voxel block in the voxel merging result into a finite element unit comprises the following steps: Determine the actual physical space coordinates of each vertex coordinate of the target voxel unit according to the position of the target voxel unit in the homogeneous voxel block in the three-dimensional voxel array; The unit node coordinates of the target voxel unit are calculated according to the actual physical space coordinates, the size of the largest homogeneous voxel block and the scaling factor.

8. A digital core-based reef limestone voxel dynamic merging modeling system, characterized in that: include: The first module is used to perform CT scanning on the reef limestone to obtain a grayscale image of the rock mass profile; The second module is used to perform image processing on the grayscale image of the rock mass profile to obtain a binary image; The third module is used to establish a three-dimensional digital core model of the rock mesostructure based on the binary image; A fourth module is used to calculate the representative volume unit size according to the three-dimensional digital core model; A fifth module is used to dynamically merge spatially continuous minimum homogeneous voxels in the three-dimensional digital core model to obtain a voxel merging result; The sixth module is used to perform modeling based on the representative volume unit size and the voxel merging result to obtain a three-dimensional pore and matrix numerical model of reef limestone.

9. An electronic device, characterized in that: including a processor and a memory; The memory is used to store programs; The processor executes the program to implement the method according to any one of claims 1 to 7.

10. A computer storage medium storing a program executable by a processor, characterized in that: The program executable by the processor is used to implement the method according to any one of claims 1 to 7 when executed by the processor.

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