Three-dimensional geological model subdivision method and device based on grid point attribute assignment and storage medium

Abstract

The invention discloses a three-dimensional geologic model subdivision method and device based on grid point attribute assignment and a storage medium, and belongs to the technical field of seismic model forward modeling. The method sequentially comprises the following steps: S1, defining a three-dimensional geologic model area based on a Cartesian coordinate system, defining a ground surface, and setting the number of grids in X, Y and Z directions as required to obtain hexahedral grids; s2, reading three-dimensional geologic model data generated by various modeling software, traversing the hexahedral mesh and the GLL points, and obtaining a mapping relation from the attributes of the three-dimensional geologic model to the GLL points of the hexahedral mesh; s3, according to the mapping relation, geological attribute values are given to the hexahedral mesh GLL points, a gridded three-dimensional geological model is formed, and three-dimensional geological model subdivision can be completed. The method is suitable for gridding subdivision of three-dimensional geologic models generated by various modeling software, is high in adaptability and expansibility, and plays an important role in large-scale application of forward numerical simulation technologies such as a spectral element method.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of seismic model forward technology, and relates to a three-dimensional geological model sectioning method, in particular to a three-dimensional geological model sectioning method based on grid point attribute assignment, equipment and a storage medium. BACKGROUND

[0002] With the continuous deepening of oil and gas exploration, the structure of target geological bodies becomes more and more complex, and the requirements for seismic acquisition design are also higher and higher. In seismic acquisition design, in order to make the observation system more reasonable and targeted, model forward is often used for analysis and optimization of the observation system. Model forward generally includes: designing mathematical and physical models or geological models, gridizing and sectioning the models to form calculation units, and forward numerical simulation to calculate the corresponding seismic response. The methods of forward numerical simulation mainly include: pseudo-spectral method, finite element method, finite difference method, spectral element method, etc. The pseudo-spectral method has poor adaptability to complex geological structure models, and the finite element method has too large calculation amount, neither of which has formed large-scale application in the field of forward numerical simulation of oil and gas exploration. The finite difference method has become the most commonly used method due to its easy implementation and high calculation efficiency, but its numerical dispersion and difficulty in processing irregular surfaces result in low accuracy of forward numerical simulation. The spectral element method appears the latest, but it combines the advantages of the finite element method and the pseudo-spectral method, and has higher calculation efficiency than the finite element method while ensuring accuracy, and has been widely used in forward numerical simulation.

[0003] The most commonly used data format of three-dimensional geological models in the field of oil and gas exploration is SEGY, which has orthogonal gridding characteristics itself, so the finite difference method does not need to be gridized and sectioned, but for emerging methods such as spectral element method, due to the high algorithm complexity, using the grid defined by SEGY data directly will result in too many grids participating in calculation, greatly reducing the calculation efficiency, and SEGY is a standard cross orthogonal format data, each column of data is strictly aligned, and cannot describe the undulating surface, so the model needs to be gridized and sectioned again.

[0004] In the prior art, firstly, some commonly used modeling software in production does not have sectioning function, resulting in that the generated three-dimensional geological model cannot be used for emerging forward methods such as spectral element method; secondly, although some modeling software has sectioning function, it cannot realize sectioning of undulating surface of three-dimensional geological model; thirdly, due to different data formats of models designed and established by various modeling software, different software needs to be matched for subsequent gridization and sectioning of the model. These problems limit the large-scale application and development of emerging forward numerical simulation methods such as spectral element method. SUMMARY

[0005] The application aims to provide a three-dimensional geological model sectioning method based on grid point attribute assignment, a device and a storage medium, so as to solve the above problems in the prior art.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the application is: A three-dimensional geological model sectioning method based on grid point attribute assignment comprises the following steps performed in sequence: S1. Defining a three-dimensional geological model region based on a Cartesian coordinate system, defining a ground surface, setting the number of grids in the X, Y and Z directions as needed, and obtaining hexahedral grids; The shape of the hexahedral grid unit is defined by a Lagrange interpolation function, and the interpolation points are also taken as GLL integral nodes in the spectral element method; S2. Reading three-dimensional geological model data generated by various modeling software, traversing the hexahedral grids and GLL points, and obtaining the mapping relationship of the attributes of the three-dimensional geological model to the hexahedral grid GLL points; S3. Assigning geological attribute values to the hexahedral grid GLL points according to the mapping relationship, forming a gridded three-dimensional geological model, and completing the sectioning of the three-dimensional geological model.

[0007] As a limitation, the step S1 comprises: Defining a three-dimensional geological model region based on a Cartesian coordinate system, defining a ground surface and a boundary surface, segmenting the three-dimensional geological model region along the depth direction through the ground surface, the boundary surface and the bottom surface, dividing it into different sub-regions, setting the number of grids in the X, Y and Z directions as needed, and obtaining hexahedral grids, the sizes of the hexahedral grids in different sub-regions are different.

[0008] As another limitation, the step S1 further comprises discarding the hexahedral grids above the ground surface to form a relief surface.

[0009] As a further limitation, the three-dimensional geological model data in the step S2 is in SEGY format.

[0010] The application further provides a computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the three-dimensional geological model sectioning method based on grid point attribute assignment described above when executing the computer program.

[0011] The application further provides a computer-readable storage medium storing a computer program for executing the three-dimensional geological model sectioning method based on grid point attribute assignment described above.

[0012] Thanks to the above technical scheme, the application has the following technical progress compared with the prior art: ① The present invention provides a three-dimensional geological model meshing method based on grid point attribute assignment. Since the data format of the model designed by various modeling software can be converted into SEGY format, it can be applied to meshing any existing three-dimensional geological model. This enhances the adaptability of forward numerical simulation technology to existing three-dimensional geological model results, gets rid of the dependence on specific modeling software, and has strong adaptability and high scalability. It plays an important role in the large-scale application of forward numerical simulation technology such as spectral element method. ② The present invention provides a three-dimensional geological model subdivision method based on grid point attribute assignment. Compared with the three-dimensional geological model in SEGY format, it can subdivide the undulating surface and adjust the number of grids according to the actual situation of the three-dimensional geological model. The grids are denser in key areas near the ground surface, making the forward numerical simulation results more accurate. ③ The present invention provides a three-dimensional geological model subdivision method based on grid point attribute assignment, which can directly apply existing three-dimensional geological model results, saves the time and cost of designing the model in the forward modeling operation, and saves a lot of time and economic costs; ④ The present invention provides a three-dimensional geological model subdivision method based on grid point attribute assignment. Compared with the inherent orthogonal grid of the SEGY format, the number of grids is greatly reduced, which greatly improves the efficiency of forward numerical simulation.

[0013] This invention is applicable to the meshing of three-dimensional geological models generated by various modeling software. It is highly adaptable and scalable, and plays an important role in the large-scale application of forward numerical simulation technologies such as the spectral element method. Attached Figure Description

[0014] Figure 1 The existing three-dimensional geological model in Example 1; Figure 2 This is a schematic diagram of the GLL points of the 4th-order Lagrange interpolation function in Example 1; Figure 3 This is a schematic diagram illustrating the number of grid cells set for different regions in Example 1; Figure 4 This is the three-dimensional geological model after segmentation in Example 1. Detailed Implementation

[0015] The present invention will be further described in detail below through specific embodiments. It should be understood that the described embodiments are only for explaining the present invention and do not limit the present invention.

[0016] Example 1 This embodiment discloses a three-dimensional geological model subdivision method based on grid point attribute assignment, which is applied to an existing three-dimensional geological model (such as...). Figure 1 As shown), it is divided into subdivisions, specifically including the following steps performed sequentially: S1. Define a three-dimensional geological model region based on the Cartesian coordinate system, define the ground surface, and set the number of grids in the X, Y, and Z directions as needed to obtain a hexahedral mesh (the shape of the hexahedral mesh element is defined by the Lagrange interpolation function, such as...). Figure 2 As shown, in the spectral element method, the interpolation points are also taken as GLL integration nodes. Based on the basic dimensions of the three-dimensional geological model, the region of the three-dimensional geological model is defined in the Cartesian coordinate system. The starting coordinates of the X and Y directions are set in this region, the default surface depth is 0, and the starting coordinate of the Z direction is set.

[0017] The surface of the 3D geological model region is defined, and the undulating surface in two dimensions is represented by a set of 3D coordinate points. By default, the bottom surface of the 3D geological model region is a plane, and its coordinate point set is automatically calculated from the model depth. The number of grids in the X, Y, and Z directions is set according to the model size and actual calculation requirements. The 3D geological model region is divided using a cross-orthogonal method to obtain a hexahedral grid.

[0018] This embodiment can also define a series of interfaces, dividing the three-dimensional geological model region into different sub-regions along the depth direction through the ground surface, interfaces, and bottom surface. The number of grids in the X, Y, and Z directions is set according to calculation needs, and the three-dimensional geological model region is divided using a cross-orthogonal method to obtain a hexahedral mesh. At this point, the hexahedral mesh size differs in different sub-regions, such as... Figure 3 As shown, the grid is denser in key areas near the ground surface, achieving the purpose of local densification of key areas and making the forward numerical simulation results more accurate.

[0019] By discarding the grid above the ground surface, a hexahedral grid can be formed, dividing the three-dimensional geological model area with undulating terrain.

[0020] S2. Read the data of the 3D geological model in SEGY format, traverse the hexahedral mesh and GLL points, and obtain the mapping relationship between the attributes of the 3D geological model and the hexahedral mesh GLL points. S3. Assign geological attribute values ​​to the GLL points of the hexahedral mesh according to the mapping relationship to form a meshed three-dimensional geological model, such as Figure 4 As shown, the three-dimensional geological model can be divided. In actual production, the 3D geological model data formats generated by various modeling software are different. Therefore, the modeling software's associated subdivision software can be used to subdivide the model into the smallest computational units before forward modeling and other calculations can be performed. If the modeling software lacks subdivision functionality or its usage period expires, even if the 3D geological model is reasonable, it cannot be subdivided, making it unusable for simulation calculations and resulting in a waste of existing resources.

[0021] In the oil and gas exploration industry, various modeling software can output 3D geological model data in SEGY format. This format inherently possesses orthogonal meshing characteristics, making it directly usable for forward numerical simulation methods such as the finite difference method without requiring meshing. However, for emerging forward numerical simulation methods such as the spectral element method and the finite element method, the algorithmic complexity is high. Directly using SEGY data would significantly reduce computational efficiency due to the excessive number of meshes involved in the calculation. Therefore, it is necessary to re-mesh the 3D geological model to reduce the number of meshes.

[0022] This embodiment first divides the 3D geological model into hexahedral meshes in a Cartesian coordinate system according to the required dimensions. Then, it directly uses the 3D geological model data in SEGY format to map the model's attributes onto the hexahedral meshes, assigning values ​​to the hexahedral meshes and giving them model attributes. This is equivalent to meshing the 3D geological model. Therefore, it can be applied to meshing any existing 3D geological model, enhancing the adaptability of forward numerical simulation technology to existing 3D geological model results, eliminating dependence on specific modeling software, and demonstrating strong adaptability and high scalability. It plays an important role in the large-scale application of forward numerical simulation techniques such as the spectral element method.

[0023] Furthermore, by establishing coordinate mapping on a grid-by-grid basis and performing attribute assignment operations, memory requirements can be reduced, making it suitable for the needs of large-scale geological model subdivision.

[0024] Example 2 This embodiment provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, to implement the above-described three-dimensional geological model subdivision method based on grid point attribute assignment.

[0025] This memory is used to store non-transitory computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0026] The processor may be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. The processor is used to execute computer-readable instructions stored in the memory.

[0027] Those skilled in the art will understand that, in order to solve the technical problem of how to achieve a good user experience, this embodiment may also include well-known structures such as communication buses and interfaces, and these well-known structures should also be included within the protection scope of this disclosure.

[0028] For a detailed description of this embodiment, please refer to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0029] Example 3 This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned three-dimensional geological model subdivision method based on grid point attribute assignment.

[0030] The computer-readable storage medium stores non-transitory computer-readable instructions thereon. When the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the methods of the foregoing embodiments are performed.

[0031] The aforementioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or portable hard drive), media with built-in rewritable non-volatile memory (e.g., memory card), and media with built-in ROM (e.g., ROM cartridge).

Claims

1. A method for partitioning a three-dimensional geological model based on grid point attribute assignment, characterized in that, This includes the following steps performed sequentially: S1. Define the three-dimensional geological model region based on the Cartesian coordinate system, define the ground surface, and set the number of grids in the X, Y and Z directions as needed to obtain a hexahedral grid; S2. Read the 3D geological model data generated by various modeling software, traverse the hexahedral mesh and GLL points, and obtain the mapping relationship between the attributes of the 3D geological model and the hexahedral mesh GLL points; S3. Assign geological attribute values ​​to the GLL points of the hexahedral mesh according to the mapping relationship to form a meshed three-dimensional geological model, thus completing the three-dimensional geological model subdivision.

2. The three-dimensional geological model subdivision method based on grid point attribute assignment according to claim 1, characterized in that, Step S1 includes: The three-dimensional geological model region is defined based on the Cartesian coordinate system. The surface and interface are defined. The three-dimensional geological model region is divided into different sub-regions along the depth direction by the surface, interface and bottom. The number of grids in the X, Y and Z directions is set as needed to obtain hexahedral grids. The size of the hexahedral grids is different in different sub-regions.

3. A three-dimensional geological model subdivision method based on grid point attribute assignment according to claim 1 or 2, characterized in that, Step S1 also includes discarding the hexahedral grid on the ground surface to form an undulating ground surface.

4. The three-dimensional geological model subdivision method based on grid point attribute assignment according to claim 3, characterized in that, The three-dimensional geological model data in step S2 is in SEGY format.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the three-dimensional geological model subdivision method based on grid point attribute assignment as described in any one of claims 1-4.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that executes the three-dimensional geological model subdivision method based on grid point attribute assignment as described in any one of claims 1-4.

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