Strong heterogeneity complex geologic modeling method based on ANSYS and APDL

Abstract

The invention discloses a strong heterogeneity complex geological modeling method based on ANSYS and APDL. The strong heterogeneity complex geological modeling method comprises the following steps: 1) acquiring layer coordinates; 2) obtaining fault coordinates and integrating data; 3) importing coordinate data to establish a geometric model; 4) dividing grids; and 5) establishing a heterogeneous mechanical model. According to the characteristics of actual geological conditions, factors such as the structural form and the fault development condition are mainly considered, a geometric model of a complex form is established, grids are divided, a command stream is established in combination with the characteristics of an APDL language, the operation accuracy and the working efficiency are improved, and the coincidence rate of the geometric model and the actual stratum form is increased; according to the method, mechanical properties and distribution rules of rocks are considered, mechanical parameter data such as elastic modulus, Poisson's ratio and density in a three-dimensional space are obtained by utilizing earthquake, logging and rock testing methods, attribute coordinates and finite element coordinates are compared, attribute assignment is performed, a heterogeneous mechanical model is established, and the method has a wide application prospect in exploration and development of oil and gas reservoirs.

Description

Technical Field

[0001] The invention relates to the technical field of geomechanical modeling methods in the process of oil and gas field exploration and development, and in particular to a strong heterogeneity complex geological modeling method based on ANSYS and APDL. Background Art

[0002] Geostress has an important impact on oil and gas migration, reservoir formation, fault sealing, structural fractures and fracturing fracture prediction. Geostress measurement based on cores or wellbores is the most direct and effective means to clarify the geostress state, but this method can only obtain geostress data within a very limited range around the well. Therefore, the application of numerical simulation in regional three-dimensional geostress research based on single well data is becoming increasingly important. At present, ANSYS software is relatively easy to operate, and with its powerful general analysis function, it has gradually become the most popular finite element analysis software in the world. It has been widely used in many fields including civil engineering and petrochemicals. Some domestic scholars have used ANSYS software for three-dimensional geostress analysis and achieved good application results.

[0003] Since the actual underground conditions are very complex, it is impossible to use a definite and specific mathematical function relationship to represent the layer morphology. When establishing a geological model, it is necessary to comprehensively consider the influence of factors such as the tectonic fluctuations of the strata, the development of faults, and the changes in mechanical characteristics, so as to reflect the actual stratum conditions as much as possible. According to the survey, the domestic research mainly uses the method of simplifying complex models to establish geometric models, and simplifies heterogeneous parameters into a few homogeneous parameters to assign values ​​to establish mechanical models, resulting in low reliability of calculation results and difficulty in truly reflecting the underground conditions. At present, there is no ANSYS modeling method for complex strata with strong heterogeneity.

[0004] At present, there are many research papers on numerical simulation and analysis of geostress field using ANSYS software, but there are few patents on modeling methods for actual strata with strong heterogeneity. The published patents are mainly in the research fields of machinery and materials, and do not involve complex modeling methods in geology, geostress research, etc., resulting in a large difference between the model and the actual situation. Most of the research results are used as theoretical guidance and have not fully achieved the original design goals of modeling and numerical simulation.

[0005] Three-dimensional geological modeling is the basis for the study and analysis of geological bodies, and is of great significance in the exploration and development of oil and gas reservoirs. Among them, structural morphology, fault distribution, mechanical characteristic parameter assignment, etc. have a great influence on the model and are important factors in whether the model can reflect the actual geological body. At present, there is no ANSYS modeling method for highly heterogeneous and complex strata. There is an urgent need for a geological modeling method suitable for highly heterogeneous and complex geological conditions to improve model compliance and work efficiency.

[0006] There are three main problems that need to be solved urgently: (1) The stratigraphic structure is complex, with large variations in thickness and poor continuity. If conventional scattered points are used for manual bottom-up modeling, the speed is slow, the efficiency is low, and errors are prone to occur during the process. It is necessary to use machines to autonomously execute commands for modeling to improve efficiency. (2) The fault morphology is irregular, and a large number of repetitive deletion and connection operations are required in the conventional modeling process, which is inefficient and prone to errors. It is necessary to establish a new data arrangement method that is easy for machine language to read and execute; (3) The actual strata change rapidly in lithology and have strong heterogeneity, and there is no clear mathematical relationship between the characteristic expression parameters. If conventional methods are used to distinguish only a small number of plots for material parameter assignment, it will be quite different from the actual geological conditions. It is necessary to distinguish the mechanical characteristic parameters of each unit involved in the calculation to express the heterogeneity in the mechanical model to a greater extent.

[0007] Therefore, a complex geological modeling method with strong heterogeneity based on ANSYS and APDL is proposed to accurately establish a three-dimensional geometric model and finely assign mechanical parameters of each unit, which effectively improves the model compliance and work efficiency. It has broad application prospects in oil and gas reservoir exploration and development. Summary of the invention

[0008] The present invention aims to provide a highly heterogeneous complex geological modeling method based on ANSYS and APDL. According to the characteristics of actual geological conditions, the method mainly considers factors such as structural morphology and fault development, establishes a geometric model of complex morphology and divides the grid, and creates a command stream in combination with the characteristics of the APDL language to improve operation accuracy and work efficiency, and improve the consistency between the geometric model and the actual stratigraphic morphology; considering the mechanical properties of rock and its distribution law, using seismic, well logging, rock testing and other methods to obtain mechanical parameter data such as elastic modulus, Poisson's ratio, density in three-dimensional space, compare the attribute coordinates with the finite element coordinates and perform attribute assignment, and establish a heterogeneous mechanical model.

[0009] This method is suitable for ANSYS mechanical modeling research with high compliance requirements in domestic oil and gas reservoir exploration and development. The establishment of relevant geometric models and mechanical models using this method can effectively improve the model compliance and work efficiency, and has broad application prospects in oil and gas reservoir exploration and development.

[0010] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows: A complex geological modeling method with strong heterogeneity based on ANSYS and APDL includes the following steps: 1) Obtaining layer coordinates: According to the structural morphology of the study area, three-dimensional coordinate data are obtained at the top and bottom surfaces of the target layer at equal intervals or non-equal intervals with a difference of less than 10% along the main structural axis. The X and Y coordinates of the corresponding points on each layer should be the same; 2) Obtain the fault coordinates and integrate the data. The three-dimensional coordinate data of the two plates of the fault on their corresponding layers obtained in step 1) are replaced with the real three-dimensional coordinates of the fault points near the fault position in the layer. The coordinates are arranged and numbered in rows or columns to form a complete keypoint file. The integration is arranged in a certain format, including keypoint numbers, X coordinates, Y coordinates and Z coordinate information, and separated by ","; 3) Import coordinate data to establish a geometric model. Import the keypoint coordinate data integrated in step 2) into ANSYS, use APDL language to write an executable command flow, and connect each coordinate point with the two adjacent coordinate points in the three-dimensional coordinate points of the top and bottom surfaces in sequence to form a triangular prism-like shape, and establish a geometric model from top to bottom to improve the accuracy and work efficiency of the geometric model; 4) Grid division: Select solid unit type and Tet-free method to divide the grid in ANSYS, and determine the grid size according to the calculation accuracy and calculation speed requirements. For example, if the subsequent calculation result requires an accuracy of 50 meters, the grid unit length must be less than 50 meters. If the calculation result requires an accuracy of 20 meters, the grid unit length must be less than 20 meters. The calculation speed is related to the number of grid units and the equipment hardware. When the equipment hardware is the same, the more grid units there are, the slower the calculation speed is. When the calculation accuracy is met, the number of grids can be reduced to speed up the calculation speed. 5) Establish a heterogeneous mechanical model, use the sedimentary phase, logging data and 3D seismic volume data of the study area for comprehensive inversion calculation, obtain the mechanical characteristic parameters of Young's modulus, Poisson's ratio and density of each 3D coordinate point in the depth domain, and export text data; use APDL language to write executable command streams for comparison, calculate the distance between each attribute point and the center point of the unit, obtain the center point of each unit and its nearest mechanical coordinate point, and assign corresponding values ​​to each unit attribute to establish a heterogeneous mechanical model. The model established by this method includes the geometric structural morphology information of the study area, the 3D geometric information of each unit of the finite element, the mechanical parameter information of each unit, etc., which has a high consistency with the actual geological environment information.

[0011] Furthermore, the structural morphology of the study area in step 1) includes the stratum dip strike direction, the anticline axis strike direction, the syncline axis strike direction and the fault strike direction.

[0012] Furthermore, the main structural axis in step 1) is the anticline axis and the main large-scale fault axis.

[0013] Furthermore, in step 2), the coordinates of each point near the fault position in the plane are replaced with the real three-dimensional coordinates of the fault, and the fault morphology is controlled by the coordinates of the key points, so that the model has a high consistency with the actual geological morphology.

[0014] Furthermore, in the step 3), the X-coordinates and Y-coordinates of the three points on the top surface and the three points on the bottom surface of the triangular prism are respectively equal, ensuring that the side surfaces of the triangular prism are planes, and the top surface and the bottom surface are planes, avoiding the multi-point group surface layer from becoming a curved surface resulting in an incomplete geometric model, and programming using the APDL language is machine executable, thereby improving work efficiency.

[0015] Furthermore, the step 3) also includes checking the quality of the geometric model, including checking the three-dimensional geometric shape, the conformity of the structural shape and the contact relationship between various geometric bodies.

[0016] Furthermore, the checking of the quality of the geometric model is specifically to check whether the overall shape of the top and bottom surfaces of the model is consistent with the actual geological structure shape, and to check whether there are gaps between the triangular prisms in the model. If the inspection result is qualified, the next step is carried out. If it is unqualified, the coordinates of the key points and their connection methods are checked for errors, and the model is remodeled after modification.

[0017] Furthermore, the step 4) also includes checking the quality of the grid, including the grid unit morphology and the number of grids.

[0018] Furthermore, the mesh quality check is specifically to use the ANSYS software to perform mesh check, requiring that the bad mesh in the check result does not exceed 1%. If the check result is qualified, the next step is carried out; if it is unqualified, the relevant parameters are modified to re-divide the mesh.

[0019] Furthermore, in step 5), the APDL language is used to write an executable command stream for comparison, specifically: 1) obtaining three-dimensional coordinates and mechanical property values; 2) obtaining unit center point coordinates; 3) calculating the distance between the unit center point coordinates and the three-dimensional property coordinates; 4) selecting the attribute with the closest distance; 5) assigning elastic modulus, Poisson's ratio and density values ​​to each unit attribute.

[0020] Furthermore, the unit center point is simplified to the coordinate average of the four corner points. The regular solid grid is generally an 8-node hexahedral grid. Due to the complexity and irregularity of the geological geometric model, it will degenerate into a 4-node tetrahedral form. After degeneration, it supports various complex and irregular model mechanical operations.

[0021] Beneficial effects of the present invention: 1. The present invention forms a complex geological modeling method with strong heterogeneity based on ANSYS software and APDL, which can guide the geological modeling work of multiple oil and gas rich areas in China. The consistency rate between the model and the actual geological conditions is improved by about 5%, playing an important role in the exploration and development of domestic oil and gas reservoirs.

[0022] 2. The method of the present invention focuses on the establishment of complex geological models with strong heterogeneity by ANSYS, fully considering the complexity of actual geological conditions, structural morphology, fault development, changes in mechanical characteristics and other factors, and combining the characteristics of the software itself to form a set of geological modeling methods suitable for complex structural morphology and strong mechanical heterogeneity, which can effectively guide the establishment of complex geological models with strong heterogeneity and improve model compliance and work efficiency.

[0023] 3. In the present invention, data integration method and APDL geometric modeling: combining the characteristics of ANSYS software and APDL language itself, the data integration method is improved to express the complex geological structure morphology as a limited number of regular coordinate data, changing the conventional bottom-up modeling direction to top-down modeling, improving the model compliance rate and operation accuracy, and improving work efficiency.

[0024] 4. In the present invention, APDL establishes a heterogeneous mechanical model: a variety of geological data analysis in the study area is comprehensively utilized to obtain the mechanical characteristic parameters such as Young's modulus, Poisson's ratio, density, etc. of each three-dimensional coordinate point, and the attribute value of the point with the smallest corresponding distance is assigned to each unit. The APDL language is used to establish a mechanical model with strong heterogeneity. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a flow chart of the geological modeling method of the present invention.

[0026] Figure 2 For the present invention, the coordinates of each point near the fault position in the plane are replaced by a real three-dimensional coordinate diagram of the fault.

[0027] Figure 3 It is a schematic diagram of the triangular prism geometric model of the present invention.

[0028] Figure 4 It is a schematic diagram of the hexahedral unit and tetrahedral geometric model of the present invention.

[0029] Figure 5 This is a solid diagram of the geometric model of Example 2 of the present invention.

[0030] Figure 6 This is a comparison diagram before and after the geometric model inspection and modification of Example 2 of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0032] Example 1 This embodiment provides a method for modeling complex geology with strong heterogeneity based on ANSYS and APDL, comprising the following steps: 1) Obtaining the layer coordinates, according to the structural morphology of the study area, along the main structural axis, equidistant or non-equidistant with a difference of less than 10%, obtain three-dimensional coordinate data on the top and bottom of the target layer, wherein the X and Y coordinates of the corresponding points on each layer should be the same. The main structural axis is the anticline axis and the main large-scale fault axis. The structural morphology of the study area includes the stratum dip strike azimuth, the anticline axis strike azimuth, the syncline axis strike azimuth and the fault strike; 2) Obtain fault coordinates and integrate data. The three-dimensional coordinate data of the two plates of the fault on their corresponding planes obtained in step 1) are replaced by the coordinates of each point near the fault position in the plane with the real three-dimensional coordinates of the fault, such as Figure 2 As shown, the replacement method is A-AF, B-BF, C-CF, D-DF, E-EF, F-FF, A'-AF', B'-BF', C'-CF', D'-DF', E'-EF', F'-FF'. After replacement, the key point coordinates can be used to control the fault morphology. The model has a high consistency with the actual geological morphology. The coordinates are arranged in rows or columns and numbered, integrated, and arranged in a certain format, including key point numbers, X coordinates, Y coordinates, and Z coordinate information, and separated by "," to become a complete key point keypoint file; 3) Import coordinate data to establish a geometric model. Import the keypoint coordinate data integrated in step 2) into ANSYS, use APDL language to write an executable command flow, and connect each coordinate point with the two adjacent coordinate points in the three-dimensional coordinate points of the top and bottom surfaces in sequence to form a triangular prism, such as Figure 3 As shown, the geometric model is established from top to bottom in the counterclockwise order of A1-B1-C1-A2-B2-C2 or clockwise order of A1-C1-B1-A2-C2-B2, so as to improve the accuracy and work efficiency of the geometric model. The X coordinates and Y coordinates of the three points on the top surface and the three points on the bottom surface of each vertex of the triangular prism are respectively equal to each other, so as to ensure that the side surfaces of the triangular prism are planes, and the top surface and the bottom surface are planes, so as to avoid the level of the multi-point group surface becoming a curved surface and causing the geometric model to be incomplete. The APDL language is used for programming, which is machine executable and improves work efficiency. Check the quality of the geometric model, including checking the conformity of the three-dimensional geometric shape, the structural shape and the contact relationship between the geometric bodies, checking whether the overall shape of the top and bottom surfaces of the model is consistent with the actual geological structure, and checking whether there are gaps between the triangular prisms in the model. If the inspection results are qualified, proceed to the next step. If not, check whether the coordinates of the key points are wrong, modify them and re-model them; 4) Divide the mesh. In ANSYS, select the solid unit type and Tet-free method to divide the mesh. The mesh size and accuracy should meet the calculation requirements. Check the mesh quality, including the mesh unit shape and mesh quantity, and use the ANSYS software to check the mesh. It is required that the bad mesh in the inspection result does not exceed 1%. If the inspection result is qualified, proceed to the next step. If not, modify the relevant parameters and re-divide the mesh; 5) Establish a heterogeneous mechanical model, use the sedimentary phase, logging data and 3D seismic volume data of the study area for comprehensive inversion calculation, obtain the mechanical characteristic parameters of Young's modulus, Poisson's ratio and density of each 3D coordinate point in the depth domain, and export text data; use APDL language to write executable command streams for comparison and establish a heterogeneous mechanical model.

[0033] The APDL language is used to write executable command streams for comparison, specifically: 1) obtain three-dimensional coordinates and mechanical property values; 2) obtain the coordinates of the unit center point; 3) calculate the distance between the unit center point coordinates and the three-dimensional property coordinates; 4) select the attribute with the closest distance; 5) assign elastic modulus, Poisson's ratio and density values ​​to each unit attribute. In step 5), the center point of the unit is simplified to the coordinate average of the four corner points, that is: EL1=(ex1,ey1,ez1), EL2=(ex2,ey2,ez2), EL3=(ex3,ey3,ez3), EL4=(ex4,ey4,ez4), Center point coordinates: ex=(ex1+ex2+ex3+ex4) / 4, ey=(ey1+ey2+ey3+ey4) / 4, ez=(ez1+ez2+ez3+ez4) / 4; like Figure 4 As shown, the unit center point is simplified to the coordinate average of the four corner points. The regular solid grid is generally an 8-node hexahedral grid. Due to the complexity and irregularity of the geological geometric model, it will degenerate into a 4-node tetrahedral form. After degeneration, it supports various complex and irregular model mechanical operations.

[0034] Example 2 This embodiment provides a method for modeling complex geology with strong heterogeneity based on ANSYS and APDL, comprising the following steps: 1) Obtaining the layer coordinates. According to the structural morphology of the study area, three 3D coordinate data are obtained at the top and bottom of the target layer at equal intervals or non-equal intervals within 10% along the main structural axis. The X and Y coordinates of the corresponding points on each layer should be the same. The main structural axis is the anticline axis or the main large-scale fault axis. The structural morphology of the study area includes the formation dip strike azimuth, the anticline axis strike azimuth, the syncline axis strike azimuth and the fault strike. The coordinates of the top and bottom surfaces are shown in Table 1. Table 1. Coordinates of points on the top and bottom surfaces 2) Obtain the coordinates of the fault and integrate the data. The two plates of the fault are obtained in step 1. The two plates are professional terms, which refer to the three-dimensional coordinate data of the fault blocks on both sides formed after the formation is disconnected. The coordinates of each point near the fault position on the plane are replaced with the real three-dimensional coordinates of the fault. After the replacement, the key point coordinates can be used to control the fault morphology. The model has a high consistency with the actual geological morphology. The coordinates are arranged in rows or columns and numbered, integrated, and arranged in a certain format, including point numbers, X coordinates, Y coordinates, and Z coordinate information, and separated by "," to become a complete key point keypoint file; 3) Import coordinate data to establish a geometric model. Import the keypoint coordinate data integrated in step 2) into ANSYS, use APDL language to write an executable command flow, and connect each coordinate point with the two adjacent coordinate points in the three-dimensional coordinate points of the top and bottom surfaces in sequence to form a triangular prism-like shape, such as Figure 3 As shown, the geometric model is established from top to bottom in the counterclockwise order of A1-B1-C1-A2-B2-C2 or clockwise order of A1-C1-B1-A2-C2-B2 to improve the accuracy and work efficiency of the geometric model. The X coordinates and Y coordinates of the three points on the top surface and the three points on the bottom surface of each vertex of the triangular prism are respectively equal to each other, ensuring that the side surfaces of the triangular prism are planes, and the top surface and the bottom surface are planes, avoiding the multi-point group surface layer from becoming a curved surface resulting in an incomplete geometric model. The APDL language is used for programming, which is machine executable and improves work efficiency. The established geometric model is as follows Figure 5 As shown; Check the quality of the geometric model, including checking the conformity of the three-dimensional geometric shape, the structural shape and the contact relationship between the geometric bodies, checking whether the overall shape of the top and bottom surfaces of the model is consistent with the actual geological structure shape, and checking whether there are gaps between the triangular prisms in the model. If the inspection results are qualified, proceed to the next step. If not, check whether the coordinates of the key points and their connection methods are wrong, and re-model after modification; Check whether there are gaps in the geometric model. After checking, there are no gaps in this model; Check whether the geometric model shape is consistent with the actual structural shape. After inspection, there are problems in the model: the fault connection method at the marked position in the figure before modification is wrong and inconsistent with the actual fault direction. After modifying the key point connection method, it is consistent with the actual fault direction. The comparison diagram before and after the geometric model modification is shown in the figure below. Figure 6 shown.

[0035] 4) Divide the mesh. In ANSYS, select the solid unit type and Tet-free method to divide the mesh. The mesh size and accuracy should meet the calculation requirements. Determine the grid size based on the calculation accuracy and calculation speed requirements. For example, if the subsequent calculation result requires an accuracy of 50 meters, the grid unit length must be less than 50 meters. If the calculation result requires an accuracy of 20 meters, the grid unit length must be less than 20 meters. The calculation speed is related to the number of grid units and the device hardware. When the device hardware is the same, the more grid units there are, the slower the calculation speed is. If the calculation accuracy is met, the number of grids can be reduced. In this embodiment, the grid size is selected to be 50 meters. Check the mesh quality, including the mesh unit shape and mesh quantity, and use the ANSYS software to check the mesh. It is required that the bad mesh in the inspection result does not exceed 1%. If the inspection result is qualified, proceed to the next step. If not, modify the relevant parameters and re-divide the mesh; 5) Establish a heterogeneous mechanical model, use the sedimentary facies, logging data and 3D seismic volume data of the study area for comprehensive inversion calculation, obtain the mechanical characteristic parameters of Young's modulus, Poisson's ratio and density of each 3D coordinate point in the depth domain as shown in Table 2, and export text data; use APDL language to write executable command streams for comparison and establish a heterogeneous mechanical model; The APDL language is used to write executable command streams for comparison, specifically: 1) obtain three-dimensional coordinates and mechanical property values; 2) obtain the coordinates of the unit center point; 3) calculate the distance between the unit center point coordinates and the three-dimensional property coordinates; 4) select the attribute with the closest distance; 5) assign elastic modulus, Poisson's ratio and density values ​​to each unit attribute; The unit center point is simplified to the coordinate average of the four corner points. The regular solid grid is generally an 8-node hexahedral grid. Due to the complexity and irregularity of the geological geometric model, it will degenerate into a 4-node tetrahedral form. After degeneration, it supports various complex and irregular model mechanical operations. In the step 5), the center point of the unit is simplified to the coordinate average of the four corner points. The coordinates of the four nodes in a unit in the model are shown in Table 3. Based on the coordinates of the center point of the unit, the arithmetic average of the three-dimensional coordinates of the four nodes can be simplified, that is, (4091.55, 623.3525, -3694.525). The distance between the center point of the unit and the coordinates of each mechanical property point is calculated, and the mechanical property of the coordinate point with the closest distance is selected for unit assignment.

[0036] Table 2 Mechanical parameters of each three-dimensional coordinate point Table 3 Coordinates of four nodes in a unit in the model In this embodiment, by comparing the three-dimensional coordinate data of different positions in the model with the actual stratum coordinate data, the geometric model morphology established by the above method is 90% consistent with the actual structural morphology; the length of the grid unit in the finite element model is 50 meters, and the number of grid units involved in the calculation is 2662975, which meets the requirements of calculation accuracy and speed. After subsequent load application and calculation analysis, the error between the calculated results of the ground stress and the measured value is controlled within 13%, and the simulation results are highly credible.

[0037] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A complex geological modeling method with strong heterogeneity based on ANSYS and APDL, characterized by: The following steps are included: 1) Obtaining layer coordinates: According to the structural morphology of the study area, three-dimensional coordinate data are obtained at the top and bottom surfaces of the target layer at equal intervals or non-equal intervals with a difference of less than 10% along the main structural axis, where the X and Y coordinates of the corresponding points on each layer are the same; 2) Obtain the fault coordinates and integrate the data. Use the three-dimensional coordinate data of the two plates of the fault in their corresponding layers obtained in step 1) to replace the coordinates of each point near the fault position in the layer with the real three-dimensional coordinates of the fault, arrange the coordinates in rows or columns and number them, and integrate them into a complete keypoint file; 3) Import coordinate data to establish a geometric model. Import the keypoint coordinate data integrated in step 2) into ANSYS, use APDL language to write an executable command flow, and connect each coordinate point with the two adjacent coordinate points in the three-dimensional coordinate points of the top and bottom surfaces in sequence to form a triangular prism-like shape, and establish a geometric model from top to bottom to improve the accuracy and work efficiency of the geometric model; 4) Divide the mesh. In ANSYS, select the solid unit type and Tet-free method to divide the mesh, and determine the mesh size according to the calculation accuracy and calculation speed requirements; 5) Establish a heterogeneous mechanical model, use the sedimentary phase, logging data and 3D seismic volume data of the study area for comprehensive inversion calculation, obtain the mechanical characteristic parameters of Young's modulus, Poisson's ratio and density of each 3D coordinate point in the depth domain, and export text data; use the APDL language to write an executable command stream for comparison, obtain the center point of each unit and its nearest mechanical coordinate point, and assign corresponding values ​​to the attributes of each unit to establish a heterogeneous mechanical model.

2. The modeling method according to claim 1, characterized in that: The structural morphology of the study area in step 1) includes the stratum dip strike direction, the anticline axis strike direction, the syncline axis strike direction and the fault strike direction.

3. The modeling method according to claim 1, characterized in that: In the step 2), the coordinates of each point near the fault position in the plane are replaced with the real three-dimensional coordinates of the fault, and then the coordinates of the key points are used to control the fault shape, so that the model has a high consistency with the actual geological shape.

4. The modeling method according to claim 1, characterized in that: In the step 3), the X coordinates and Y coordinates of the three points on the top surface and the three points on the bottom surface of the triangular prism are respectively equal to each other, ensuring that the side surfaces of the triangular prism are planes, and the top surface and the bottom surface are planes, avoiding that the plane of the multi-point group surface becomes a curved surface resulting in an incomplete geometric model, and programming is performed by the machine using the APDL language, thereby improving work efficiency.

5. The modeling method according to claim 1, characterized in that: The step 3) also includes checking the quality of the geometric model, including checking the three-dimensional geometric shape, the conformity of the structural shape and the contact relationship between various geometric bodies.

6. The modeling method according to claim 5, characterized in that: The checking of the quality of the geometric model specifically includes checking whether the overall shape of the top and bottom surfaces of the model is consistent with the actual geological structure shape, and checking whether there are gaps between the triangular prisms in the model. If the inspection result is qualified, the next step is carried out. If it is unqualified, the coordinates of the key points and their connection methods are checked for errors, and the model is remodeled after modification.

7. The modeling method according to claim 1, characterized in that: The step 4) also includes checking the mesh quality, including the mesh unit morphology and the mesh quantity.

8. The modeling method according to claim 7, characterized in that: Specifically, the mesh quality check is to use the ANSYS software to perform mesh check, requiring that the bad mesh in the check result does not exceed 1%. If the check result is qualified, the next step is carried out. If it is unqualified, the relevant parameters are modified and the mesh is re-divided.

9. The modeling method according to claim 1, characterized in that: In the step 5), the APDL language is used to write an executable command stream for comparison, specifically: 1) obtaining three-dimensional coordinates and mechanical property values; 2) obtaining unit center point coordinates; 3) calculating the distance between the unit center point coordinates and the three-dimensional property coordinates; 4) selecting the attribute with the closest distance; 5) assigning elastic modulus, Poisson's ratio and density values ​​to each unit attribute.

10. The modeling method according to claim 9, characterized in that: The cell center point is simplified to the average coordinates of the four corner points.

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