Equivalent conversion method for automatically converting three-dimensional geologic model into finite element model

Abstract

The invention discloses an equivalent conversion method for automatically converting a three-dimensional geologic model into a finite element model, and relates to the technical field of engineering information models.The method comprises the steps that grid nodes of each geologic body model in the three-dimensional geologic model in a CAD platform and the original connection relation of the grid nodes are obtained; establishing a stratum interface point set of each geologic body model and a corresponding set plane boundary; establishing a full model boundary of the three-dimensional geologic model; the stratum type is judged; establishing a new connection relation fusing the stratum interface point set, the top surface set, the bottom surface set and the lenticular body set and the grid nodes corresponding to the grid node numbers in the sets; and according to the numbers of the grid nodes, the space coordinates and the new connection relation of the grid nodes, a model is generated in CAE software through reconstruction. According to the method, the grid nodes are obtained from the CAD platform through cross validation and deformity correction and repair, and the calculation model is reconstructed in the CAE platform in a mode of reestablishing the connection, so that the model is automatically converted from the CAD platform to the CAE platform.

Description

Technical Field

[0001] The invention relates to the technical field of engineering information models, in particular to a method for automatically converting a three-dimensional geological model into a finite element model. Background Art

[0002] The three-dimensional geological model is the basic model for geotechnical engineering design. Most existing three-dimensional geological models are built using CAD software, which does not have numerical analysis functions. The existing public methods for converting CAD to CAE (computer-aided engineering) models are mainly divided into two categories:

[0003] (1) Model reconstruction technology, that is, extracting the three-dimensional geological model data from the CAD model and regenerating it in the CAE platform, such as invention patent CN111159797B, which regenerates the computational model in the finite element by extracting information from the BIM (three-dimensional geological model); such as invention patent CN114595610B, which regenerates the technical model in the finite element by extracting tunnel and simple formation parameters;

[0004] The disadvantage of this technology is that it cannot achieve equivalent conversion of complex three-dimensional geological models. The main reason is that three-dimensional geological models are mostly expressed in the form of Mesh in CAD, with relatively low accuracy. Directly reconstructed CAE models usually cannot be calculated because of the embedding or separation between adjacent stratigraphic bodies; or because of some deformed areas in the CAD model itself, it cannot be meshed in CAE.

[0005] (2) Transition software conversion technology, that is, in the process of converting CAD to CAE, the CAD model is processed by transition software and then imported into CAE, such as invention patent CN114462131B, which realizes model conversion through STL2STP; such as invention patent CN116090078B, which realizes model conversion through EMTransfer or Hypermesh;

[0006] The disadvantage of this technology is that technicians need to manually perform a lot of corrections on the model in the transition software. Every adjustment of the model in CAD needs to be reprocessed in the transition software, which is a lot of work; and this method cannot realize the automated calculation and analysis of the BIM model. Summary of the invention

[0007] In order to overcome the defects in the above-mentioned prior art, the present invention provides a method for automatically converting a three-dimensional geological model into a finite element model, and realizes the conversion of the three-dimensional geological model from CAD to CAE by combining equivalent correction and model reconstruction.

[0008] To achieve the above object, the present invention adopts the following technical solutions, including:

[0009] A method for automatically converting a three-dimensional geological model into a finite element model, comprising the following steps:

[0010] Step 1: Obtain the grid nodes of each geological body model in the three-dimensional geological model and the original connection relationship of the grid nodes; the grid nodes include their numbers and spatial coordinates; the spatial coordinates include horizontal coordinates X, horizontal coordinates Y and vertical coordinates Z; the original connection relationship of the grid nodes is: the grid nodes are connected to each other according to the original connection relationship to form multiple grid surfaces, and the multiple grid surfaces can surround and form a complete geological body model. The number of geological body models is N, N≥1, and N geological body models are combined into a three-dimensional geological model;

[0011] Step 2: Establish a stratum interface point set and a corresponding set plane boundary of each geological body model; establish a full model boundary of a three-dimensional geological model; the stratum interface point set includes an upper stratum interface point set and a lower stratum interface point set;

[0012] Step 3: Define the formation type judgment rule, and determine the formation type as conventional formation, pinch-out formation or lens formation according to the collective plane boundary of the geological body model;

[0013] Step 4: According to the stratum interface point set and the original connection relationship of the geological body model, a fused stratum interface point set, a top surface set, a bottom surface set and a lens set are established, and a new connection relationship between the grid node numbers in each set and the grid nodes is established;

[0014] Step 5: Generate a CAE model by reconstruction in the CAE software according to the mesh node numbers, spatial coordinates and new connection relationships of the mesh nodes.

[0015] Preferably, the step 2 of establishing a set of stratum interface points and a corresponding set plane boundary of each geological body model is as follows:

[0016] Step 2.1: Select a geological body model and obtain its grid nodes;

[0017] Step 2.2: Project each grid node vertically onto the geological model in turn, and classify the grid node numbers into upper and lower stratum interface point sets and temporary number sets according to the projection relationship, as follows:

[0018] If the number of projection points p obtained by projecting the grid node is greater than one, and the grid node coincides with the projection point p with the largest vertical coordinate Z, the grid node number is classified into the upper stratum interface point set; if the number of projection points p obtained by projecting the grid node is greater than one, and the grid node coincides with the projection point p with the smallest vertical coordinate Z, the grid node number is classified into the lower stratum interface point set; if the number of projection points p obtained by projecting the grid node is greater than one, and the grid node does not coincide with the projection point p with the largest and smallest vertical coordinates Z, the grid node number is classified into the temporary number set; if the number of projection points p obtained by projecting the grid node is equal to one, the grid node number is classified into both the upper and lower stratum interface point sets, and is defined as a special grid node number;

[0019] Step 2.3: Determine whether there is data in the temporary number set. If so, execute step 2.4; otherwise, execute step 2.5.

[0020] Step 2.4: Select a grid node number in the temporary number set, define the grid node as MB, and classify the MB number into the upper or lower stratum interface point set according to the original connection relationship. The specific steps are as follows:

[0021] Step 2.4.1: According to the original connection relationship, all grid node numbers directly connected to the MB are screened, and non-special grid node numbers among the grid node numbers directly connected to the MB are classified into the screening number set;

[0022] Step 2.4.2: Determine whether there is a grid node number in the screening number set that belongs to the upper or lower stratum interface point set. If so, define the grid node as PB, and determine the ownership of the MB number based on the PB number, specifically:

[0023] If the number of PB belongs to the upper stratum interface point set, the number of MB is included in the set; otherwise, it is included in the lower stratum interface point set, and MB is removed from the temporary number set, and step 2.4.2 is terminated directly; if there is no PB, step 2.4.3 is executed;

[0024] Step 2.4.3: According to the original connection relationship, screen all the grid node numbers directly connected to the grid nodes corresponding to all the grid node numbers in the screening number set, and classify the non-special grid node numbers therein into the screening number set. Select the execution content according to whether there are new non-special grid node numbers included in the screening number set. If there are, directly return to step 2.4.2; if not, directly remove MB from the temporary number set and end step 2.4.3;

[0025] Repeat step 2.4 until the temporary number set is empty;

[0026] Step 2.5: Obtain the boundary point number in the upper or lower stratum interface point set through the upper or lower stratum interface point set and the original connection relationship, and then determine the plane boundary of the set according to the original connection relationship. The specific steps are as follows:

[0027] Step 2.5.1: Filter out the grid node numbers that meet the boundary point rule from the upper or lower stratum interface point set, and define them as boundary point numbers; the boundary point rule includes two points, and satisfying any one of the points satisfies the boundary point rule, specifically: (1) the grid node number is a special grid node number; (2) the grid node number itself is a non-special grid node number located in the upper or lower stratum interface point set, and according to the original connection relationship, there is a grid node number that is a non-special grid node number located in the lower or upper stratum interface point set and is directly connected to it;

[0028] Step 2.5.2: Obtain all boundary point numbers, connect the boundary point numbers that are directly connected in the original connection relationship in sequence, and project them along the vertical direction to a fixed horizontal plane to obtain a boundary defined as the collective plane boundary;

[0029] Repeat steps 2.1 to 2.5 to establish a set of stratum interface points and a set plane boundary for each geological body model;

[0030] The full model boundary of the three-dimensional geological model meets two requirements: (1) on a fixed horizontal plane, all the collective plane boundaries are not located outside the full model boundary; (2) when the previous requirement is met, the area contained in the full model boundary is the smallest.

[0031] Preferably, the formation type judgment rules in step 3 are lens formation rule and pinch-out formation rule respectively; the lens formation rule is that the set plane boundary corresponding to the selected geological body model is completely within the boundary of the whole model; the pinch-out formation rule is that the set plane boundary corresponding to the selected geological body model is partially within the boundary of the whole model, and partially overlaps with the boundary of the whole model;

[0032] The determination of the formation type is specifically as follows: if the collective plane boundary corresponding to the selected geological body model satisfies the lens formation rule, then the formation type is defined as a lens formation; if the collective plane boundary corresponding to the selected geological body model satisfies the pinch-out formation rule, then the formation type is defined as a pinch-out formation; if neither is satisfied, then the formation type is defined as a conventional formation.

[0033] Preferably, the steps of establishing the fused stratum interface point set, the top surface set, the bottom surface set and the lens set, and establishing a new connection relationship between the grid node numbers in the set and the grid nodes are as follows:

[0034] Step 4.1: Select an upper or lower stratum interface point set of a geological body model, and perform vertical interpolation projection on the grid nodes corresponding to each grid node number in the set to all stratum interface point sets of the remaining N-1 geological body models; record the stratum interface point set of the selected geological body model as the selected set, and establish a corresponding relationship between the two; record the stratum interface point set of the projected geological body model as the projection set, and establish a corresponding relationship between the two; when performing vertical interpolation projection, store the results separately according to the difference between the selected set and the projection set, and call them the comparison set, which corresponds to the selected set and the projection set at the same time;

[0035] Step 4.2: Compare each selected set with the corresponding comparison set in turn. If there is a surface overlap relationship between the two sets, then record that the selected set corresponding to the comparison set overlaps with the projection set surface, and establish a fused stratum interface point set. At the same time, determine whether to establish an independent set and its attributes;

[0036] The specific process of step 4.2 is as follows:

[0037] Step 4.2.1: Establishing a temporary fused stratum interface point set corresponding to the transition of the comparison set; the transition correspondence means that the selected set and the projection set are simultaneously corresponding to the same set as the comparison set;

[0038] Step 4.2.2: Compare the selected set with the comparison set, and select the grid node numbers that meet the error overlap in the selected set, and store them in the temporary fused formation interface point set corresponding to the transition of the comparison set;

[0039] The grid node numbers satisfying the error overlap are: the grid nodes corresponding to the grid node numbers in the selected set and the grid nodes corresponding to the grid node numbers in the comparison set satisfy the same horizontal coordinates X and Y, and the absolute value of the difference in vertical coordinate Z is less than the error ε1;

[0040] Step 4.2.3: Connect the grid nodes corresponding to the grid node numbers in the temporary fused stratum interface point set that is not empty according to the original connection relationship. If a surface can be formed after the connection, it is recorded that the selected set corresponding to the temporary fused stratum interface point set and the comparison projection set surface domain coincide with each other;

[0041] Step 4.2.4: Determine whether all grid node numbers in the selected set are subsets of the union of all temporary fused stratum interface point sets corresponding to them; if not, establish an independent set, and store the grid node numbers in the selected set that are not included in the union in the independent set, and determine their attributes according to the grid node numbers stored in the independent set; if so, do not establish an independent set;

[0042] If the selected set does not have a corresponding temporary fused stratum interface point set, an independent set is established, and all grid node numbers of the selected set are stored in the independent set, and at the same time, its attributes are determined according to the grid node numbers stored in the independent set;

[0043] The independent set corresponds to the set of stratum interface points corresponding to the selected set;

[0044] The method of determining the attribute of the independent set according to the grid node numbers stored in the independent set is as follows: if the Z value of the grid nodes corresponding to all the grid node numbers in the independent set is greater than the Z value of the grid nodes with the same horizontal coordinate among the grid nodes corresponding to all the comparison set grid node numbers in the selected set, then the attribute of the independent set is defined as Top; if the Z value of the grid nodes corresponding to all the grid node numbers in the independent set is less than the Z value of the grid nodes with the same horizontal coordinate among the grid nodes corresponding to all the comparison set grid node numbers in the selected set, then the attribute of the independent set is defined as Down; otherwise, the attribute is defined as Mid;

[0045] Repeat until all the formation interface point sets of all geological body models are selected as the set to perform all the operations of steps 4.1-4.2;

[0046] Step 4.3: merge the temporary fused stratum interface point sets corresponding to the selected set and the projection set with the same inversion into one, and merge the corresponding relationship; then delete the temporary fused stratum interface point sets whose sets are empty and whose grid nodes corresponding to the grid node numbers in the sets cannot form a surface by connecting them according to the original connection relationship;

[0047] Step 4.4: Obtain two corresponding formation interface point sets in the fused formation interface point set, record them as a fused corresponding set pair, and then obtain two corresponding geological body models. If there is a geological body model whose formation type is a lens formation, then convert the fused formation interface point set into an independent set, which corresponds to the formation interface point set corresponding to the lens formation in the fused corresponding set pair; the independent set attribute is Mid;

[0048] Step 4.5: Place all fused formation interface point sets and independent sets in the set group to be corrected, and correct each set in the set group to be corrected;

[0049] Step 4.6: patch and fuse the stratum interface point set, and establish a new connection relationship in which the grid node numbers correspond to the grid nodes;

[0050] Step 4.7: Obtain all independent sets with the attribute Mid, establish c lens sets and their new connection relationships; where c≥0;

[0051] Step 4.8: Obtain all independent sets with the attributes of Top and Down, and establish a top surface set and b bottom surface sets; a≥1, b≥1.

[0052] Preferably, in step 4.1, the specific method of the vertical interpolation projection is: obtaining points with the same horizontal coordinates X and Y as those of all grid node numbers corresponding to the selected set by spatial interpolation in the projection set;

[0053] In step 4.3, the inversion is the same means that the projection set corresponding to the temporary fusion formation interface point set A and the selected set corresponding to the temporary fusion formation interface point set B correspond to the same formation interface point set, and the selected set corresponding to the temporary fusion formation interface point set A and the projection set corresponding to the temporary fusion formation interface point set B correspond to the same formation interface point set;

[0054] In step 4.3, the merged correspondence refers to the transformation of the merged set into a fused formation interface point set, and directly corresponds to the selected set corresponding to the two temporary fused formation interface point sets and the formation interface point set corresponding to the projection set.

[0055] Preferably, in step 4.5, each set in the set to be corrected is corrected, and the specific process is as follows:

[0056] Step 4.5.1: Select a set from the set to be corrected as the set to be corrected, and obtain the spatial coordinates of the grid nodes corresponding to the grid node numbers in the set;

[0057] Step 4.5.2: Obtain the interpolated vertical coordinates Z1 of the grid nodes corresponding to all grid node numbers in the set to be corrected through orthogonal test; solve the absolute value of the difference between the vertical coordinate Z of each grid node and the interpolated vertical coordinate Z1, and place the grid node numbers whose absolute values ​​are greater than the deviation ε2 in the set of nodes to be corrected, and place the remaining node numbers in the standard node set;

[0058] The orthogonal test described in step 4.5.2 obtains the interpolated vertical coordinate Z1 of the grid node, as follows:

[0059] Step 4.5.2a: Place all grid node numbers in the set to be corrected into the orthogonal test set;

[0060] Step 4.5.2b: Select a grid node corresponding to the grid node number in the orthogonal test set, record it as the node to be found, and remove its number from the orthogonal test set;

[0061] Step 4.5.2c: Obtain a point with the same horizontal coordinate as the node to be determined from among the grid nodes corresponding to all grid node numbers in the orthogonal test set by spatial interpolation as an interpolation node; the vertical coordinate Z of the interpolation node is the interpolation vertical coordinate Z1 of the node to be determined;

[0062] Step 4.5.3: Perform an abnormality check on the grid nodes corresponding to the grid node numbers in the set of nodes to be corrected. If the check result is abnormal, the value of the vertical coordinate Z of the grid node is modified to the value of the interpolated vertical coordinate Z1; if the check result is not abnormal, the value of the vertical coordinate Z of the grid node is maintained unchanged; repeat this step until all grid nodes corresponding to the grid node numbers in the set of nodes to be corrected have been checked for abnormality;

[0063] The deformity examination described in step 4.5.3 is as follows:

[0064] Step 4.5.3a: Select a grid node number from the set of nodes to be corrected; obtain the grid node corresponding to the grid node number, and record it as the node to be checked;

[0065] Step 4.5.3b: Obtain multiple grid node numbers from the standard node set that can uniquely surround the node to be inspected in the minimum horizontal plane or the minimum inner angle uniquely surround the node to be inspected, and record them as the standard node group;

[0066] The minimum unique encirclement of the node to be inspected within the plane range satisfies that the projection of the grid nodes corresponding to the multiple grid node numbers in the standard node set to the fixed horizontal plane after connection can enclose a polygon by itself, and the polygon does not contain the projections of the grid nodes corresponding to all the grid node numbers in the standard node set in the fixed horizontal plane, but contains the projection of the node to be inspected, and the number of sides of the polygon is the smallest, and the area of ​​the polygon is the smallest;

[0067] The large inner angle minimum unique surrounding node to be inspected means that, when the polygon formed by connecting the grid nodes corresponding to any multiple grid node numbers in the standard node set and projecting onto a fixed horizontal plane cannot contain the projection of the node to be inspected, multiple grid nodes corresponding to the grid node numbers in the standard node set are selected and connected to the node to be inspected, and the projection onto the fixed horizontal plane can form a polygon, the polygon does not contain the projections of the grid nodes corresponding to all the grid node numbers in the standard node set in the fixed horizontal plane, and the inner angle corresponding to the projection of the node to be inspected is the largest, the number of sides of the polygon is the smallest, and the area of ​​the polygon is the smallest;

[0068] Step 4.5.3c: Solve the average node of the standard node group in space, and solve the average distance between the standard node group and the average node in space, recorded as La; solve the distance Lb between the node to be tested and the average node in space; if Lb / La is greater than the slenderness ratio, return that the node to be tested is deformed, otherwise return that it is not deformed;

[0069] The X, Y and Z of the average node are equal to the average values ​​of the X, Y and Z of the grid nodes corresponding to all grid node numbers in the standard node group; the slenderness ratio is a set parameter;

[0070] Step 4.5.4: Clear the node set to be corrected, and remove the selected set to be corrected from the set group to be corrected;

[0071] Repeat steps 4.5.1-4.5.4 until the set to be corrected is empty.

[0072] Preferably, the patching and fusion of the formation interface point set in step 4.6 and the establishment of a new connection relationship in which the grid node numbers correspond to the grid nodes are as follows:

[0073] Step 4.6.1: Select a fusion formation interface point set, connect the grid nodes corresponding to the grid node numbers in the set according to the original connection relationship to form two grid surfaces; extract the contours of the two grid surfaces, the grid node numbers on the contours and their original connection relationships, and record them as old contours, old contour node numbers and old contour connection relationships;

[0074] Step 4.6.2: Project the old contour along the vertical direction onto a fixed horizontal plane to obtain a new contour projection that can just surround the old contour projection in the fixed horizontal plane;

[0075] Step 4.6.3: Obtain the old contour node number corresponding to the new contour projection as the new contour node number, and determine whether it is necessary to add a new grid node and its corresponding number and original connection relationship; if it is necessary to add, store the newly added grid node number in the selected fusion stratum interface point set, and use the newly added grid node number as the new contour node number; according to the connection relationship of the new contour projection vertices, add the connection relationship between the newly added grid node and the existing grid node to the original connection relationship;

[0076] Step 4.6.3 determines whether a new grid node needs to be added and its corresponding number and original connection relationship, as follows:

[0077] Step 4.6.3a: Determine whether there is an intersection between the two old contour projections, and the intersection does not coincide with the projection point of the grid node corresponding to the old contour node number; if so, it is necessary to add a new grid node with the same horizontal coordinate as the intersection, and assign it a number that is different from the existing grid node numbers, and execute step 4.6.3b; if not, it does not need to be added, and end;

[0078] Step 4.6.3b: Get the edge of the old contour corresponding to the projection of the old contour that forms the intersection, obtain the points on the two old contour edges with the same horizontal coordinates as the intersection through linear interpolation, and solve the average value of the vertical coordinates Z of the two points as the value of the vertical coordinate Z of the newly added grid node;

[0079] Step 4.6.4: Determine whether the newly added grid node number needs to be stored in the unselected fused stratum interface point set or the independent set with the attribute Mid at the same time. If necessary, store the newly added grid node number in the unselected fused stratum interface point set or the independent set with the attribute Mid.

[0080] Step 4.6.4 determines whether the newly added grid node number needs to be stored in the unselected fused stratum interface point set or the independent set with the attribute Mid, as follows:

[0081] Step 4.6.4a: Search for the unselected fused stratum interface point set corresponding to the same stratum interface point set as the selected fused stratum interface point set and the independent set with the attribute of Mid;

[0082] Step 4.6.4b: connect the unselected fused stratum interface point set in step 4.6.4a and the grid nodes corresponding to the grid node numbers in the independent set with the attribute Mid according to the original connection relationship to form at least one grid surface SA, and project it onto a fixed horizontal plane along the vertical direction;

[0083] Step 4.6.4c: If the point where the newly added grid node is projected onto the fixed horizontal plane along the vertical direction is located on the contour of the projection of a certain grid surface SA, the number of the newly added grid node is stored in the corresponding unselected fused stratum interface point set described in 4.6.4a or in the independent set with the attribute Mid;

[0084] Step 4.6.5: If there are points that are spatially close to the grid nodes corresponding to the grid node numbers in the selected fused stratum interface point set, only the number of one of the points is retained in the set, and the numbers of the remaining points are discarded; the grid nodes are spatially close means that the spatial distance between the grid nodes is less than the distance difference ε3; the distance difference ε3 is an artificially set fixed parameter;

[0085] Step 4.6.6: Using the new contour projection as the boundary and in accordance with the triangulated network restricted growth principle, establish a new connection relationship between the grid node numbers and the grid nodes in the selected fused stratum interface point set;

[0086] The method of taking the new contour projection as the boundary and restricting the growth of the triangulated network according to the principle of limiting the growth of the triangulated network means that the grid nodes corresponding to the grid node numbers in the fused stratum interface point set are connected according to the new connection relationship to meet the following requirements: (1) all grids are triangular grids and the grid nodes corresponding to all grid node numbers in the set are vertices of triangles; (2) the range of all grids after being projected onto a fixed horizontal plane does not exceed the projection of the new contour; and (3) the projections of all triangular grids onto the fixed horizontal plane do not overlap or intersect with each other.

[0087] Preferably, the step 4.7 establishes c lens sets, and the specific process is as follows:

[0088] Step 4.7.1: Select an independent set with the attribute Mid, called the independent set NA, and select all independent sets that can correspond to the same geological body model across sets with the independent set NA from the other independent sets with the attribute Mid, called the independent set group NB;

[0089] Step 4.7.2: According to the number of formation interface point sets corresponding to the independent set NA, establish temporary lens sets with the same number, copy all grid node numbers in the independent set NA to all temporary lens sets, and during each copying process, simultaneously transfer a formation interface point set correspondence relationship of the independent set NA to the temporary lens set;

[0090] Step 4.7.3: In the independent set group NB, select the independent set NC that can correspond to the same geological body model as the temporary lens set across the set, copy all grid node numbers in the independent set NC to the temporary lens set, and transfer a formation interface point set correspondence relationship of the independent set NC to the temporary lens set;

[0091] The corresponding relationship between the formation interface point sets transmitted by the independent set NC satisfies that the formation interface point set in the corresponding relationship and the formation interface point set corresponding to the temporary lens set correspond to the same geological body model;

[0092] The independent set transfers the corresponding relationship between the stratum interface point set to the temporary lens set, which means deleting the corresponding relationship between the independent set and the stratum interface point set, and establishing the corresponding relationship between the temporary lens set and the stratum interface point set;

[0093] The cross-set correspondence means that there is at least one identical one in all geological body models corresponding to one of the stratum interface point sets corresponding to the independent sets;

[0094] After the transfer in steps 4.7.2 and 4.7.3 is completed, the independent set is immediately judged. If the independent set no longer corresponds to any formation interface point set, the independent set is deleted;

[0095] Repeat steps 4.7.1-4.7.3 until all independent sets with the attribute Mid are deleted;

[0096] Step 4.7.4: Keep the storage content and corresponding relationship of the temporary lens set unchanged, and convert the temporary lens set into a lens set;

[0097] Step 4.7.5: According to the lens triangle mesh growth principle, establish a new connection relationship for all lens sets;

[0098] The lens triangular mesh growth principle described in step 4.7.5 satisfies the following requirements: (1) all meshes are triangular meshes and all mesh nodes corresponding to the mesh node numbers in the set are vertices of triangles; (2) the meshes can be enclosed into a unique closed space.

[0099] Preferably, in step 4.8, a top surface set and b bottom surface set are established, and the specific process is as follows:

[0100] Step 4.8.1: Select an independent set with the attribute of Top or Down, recorded as the independent set ND, obtain the formation interface point set corresponding to the independent set ND, recorded as the formation interface point set C, and then obtain all the fused formation interface point sets corresponding to the formation interface point set, recorded as the fused formation interface point set C';

[0101] Step 4.8.2: Connect the grid nodes corresponding to the grid node numbers in the formation interface point set C according to the original connection relationship to obtain the grid surface SB; connect the grid nodes corresponding to the grid node numbers in the fused formation interface point set C' according to the new connection relationship to obtain the grid surface SC; project the contours of the grid surfaces SB and SC onto a fixed horizontal plane at the same time, obtain the part of the contour projection of the grid surface SC that does not overlap with the contour projection of the grid surface SB, and store the grid node numbers corresponding to the non-overlapping parts in different grid boundary groups according to the new connection relationship;

[0102] The grid node numbers in the grid boundary group meet the requirement that a line can be formed after being connected according to the new connection relationship;

[0103] Step 4.8.3: storing the numbers of the grid nodes in the grid boundary group that satisfy the integration into the independent set relationship into the selected independent set;

[0104] The said satisfying integration into the independent set relationship refers to a mesh boundary group: the triangular mesh formed by connecting the mesh nodes corresponding to the mesh node numbers in the mesh boundary group with the mesh nodes corresponding to any two mesh node numbers in the independent set cannot overlap with the projection of the mesh surface SC along the vertical direction to the fixed horizontal plane;

[0105] Step 4.8.4: Establish a new connection relationship for the independent set, and the new connection relationship meets the following requirements: the mesh surface formed by connecting the mesh nodes corresponding to the mesh node numbers in the independent set according to the new connection relationship will not exceed the projection of the mesh surface SB contour along the vertical direction to the fixed horizontal plane, and will not overlap with the projection of the mesh surface SC, and all of them are triangular meshes;

[0106] Step 4.8.5: Convert the independent set to a top surface set or a bottom surface set according to its attribute. Specifically, if the attribute is Top, convert it to a top surface set; if the attribute is Down, convert it to a bottom surface set.

[0107] If the fused stratum interface point set C' is not obtained in step 4.8.1, directly execute step 4.8.5.

[0108] Preferably, the CAE model is generated by reconstruction in CAE software in step 5, as follows:

[0109] Step 5.1: Generate mesh nodes corresponding to all mesh node numbers in the fusion interface point set, top surface set, bottom surface set and lens set in the CAE software;

[0110] Step 5.2: Select a geological body model of non-lens stratum type, obtain the fused interface point set, top surface set or bottom surface set corresponding to the upper and lower stratum interface point sets, and connect them in the CAE platform according to the new connection relationship to form two grid surfaces corresponding to the upper and lower stratum interface point sets, which are recorded as the upper and lower grid surfaces of the geological body respectively;

[0111] Step 5.3: Through the stretching operation of the CAE platform, the upper / lower grid surface of the geological body is stretched downward / upward to the lower / upper grid surface to form a CAE model corresponding to the geological body model;

[0112] Repeat steps 5.2-5.3 until the corresponding CAE models of all non-lens formation geological models are established;

[0113] Step 5.4: Select the geological body model of lens strata, obtain the corresponding lens set, and form a closed body in the CAE platform according to the new connection relationship, which is the CAE model corresponding to the geological body model; repeat this step to establish the CAE models of all lens strata;

[0114] Step 5.5: In the CAE platform, the CAE model of the lenticular formation is subtracted from the CAE model of the non-lenticular formation by Boolean operation; the CAE model after the Boolean operation and the CAE model of the lenticular formation together constitute the CAE model of the three-dimensional geological model.

[0115] The advantages of the present invention are:

[0116] (1) The contact surface of the geological model in the CAD platform is determined and integrated by vertical interpolation projection, avoiding the problem of small gaps or embedding in the contact surface of the reconstructed geological model in the CAE platform, which leads to the problem of incomputation.

[0117] (2) Spatial interpolation is used to cross-validate and correct the deformity of each point in the stratigraphic layer, thus avoiding the problem of being unable to divide the grid when reconstructing the geological model in the CAE platform.

[0118] (3) The entire conversion process can be realized by computer, that is, the automatic conversion of geological models from CAD platform to CAE can be realized. At the same time, the model reconstruction method is used to complete the conversion of the three-dimensional geological model in the CAD platform to the finite element model in the CAE platform without the intervention of software manufacturers.

[0119] (4) The grid node numbers are stored in correspondence with the spatial coordinates and connection relationships, and the numbers are only stored in the set, so that when the spatial coordinates and connection relationships change, the spatial coordinates and connection relationships corresponding to the numbers in all sets change synchronously. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] Figure 1 This is a schematic diagram of the cross section of the three-dimensional geological model.

[0121] Figure 2 Schematic diagram of the corresponding relationship between various sets.

[0122] Figure 3 Schematic diagram of dividing the upper and lower stratum interface point sets based on projection relationships.

[0123] Figure 4 It is a schematic diagram of the minimum unique surrounding node to be inspected within the plane range.

[0124] Figure 5 This is a schematic diagram of the node to be inspected with the largest inner angle minimum unique enclosing semi-enclosing.

[0125] Figure 6 Schematic diagram of deformity examination.

[0126] Figure 7 A schematic diagram is established to fuse the new connection relationship of the set of stratigraphic interface points.

[0127] The reference numerals are as follows:

[0128] 1-grid node; 2-grid node number; 3-spatial coordinate; 4-average node; 5-conventional formation; 6-pinch-out formation; 7-lens formation; 8-projection point p; 9-node to be checked; 10-intersection point; 11-old contour projection; 12-new contour projection. DETAILED DESCRIPTION

[0129] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0130] Depend on Figure 1-Figure 7 As shown, a method for automatically converting a three-dimensional geological model into a finite element model includes the following steps:

[0131] Step 1: Obtain the grid nodes and original connection relationships of each geological body model in the three-dimensional geological model in the CAD platform, and store them separately.

[0132] The grid node includes its number and spatial coordinates; the grid node spatial coordinates include horizontal coordinate X, horizontal coordinate Y and vertical coordinate Z.

[0133] The original connection relationship of the grid nodes is: in the CAD platform, the grid nodes are connected to each other according to the original connection relationship to form multiple grid surfaces, and the multiple grid surfaces can surround and form a complete geological body model; the number of the geological body models is N (N≥1), and the N geological body models are combined into a three-dimensional geological model.

[0134] Step 2: Establish a stratum interface point set and a corresponding set plane boundary for each geological body model; establish a full model boundary of a three-dimensional geological model; the stratum interface point set includes an upper stratum interface point set and a lower stratum interface point set.

[0135] The step 2 is to establish a set of stratum interface points and a corresponding set plane boundary of each geological body model. The specific process is as follows:

[0136] Step 2.1: Select a geological body model, obtain its grid nodes from the stored results of step 1, and establish the upper and lower stratum interface point sets of the geological body model.

[0137] Step 2.2: In the CAD platform, each grid node is vertically projected onto the geological model in turn, and the grid node numbers are classified into the upper and lower stratum interface point sets and temporary number sets according to the projection relationship, as follows:

[0138] If the number of projection points p obtained by projecting the grid node is greater than one, and the grid node coincides with the projection point p with the largest vertical coordinate Z, the grid node number is included in the upper stratum interface point set; if the number of projection points p obtained by projecting the grid node is greater than one, and the grid node coincides with the projection point p with the smallest vertical coordinate Z, the grid node number is included in the lower stratum interface point set; if the number of projection points p obtained by projecting the grid node is greater than one, and the grid node does not coincide with the projection point p with the largest and smallest vertical coordinates Z, the grid node number is included in the temporary number set; if the number of projection points p obtained by projecting the grid node is equal to one, the grid node number is included in both the upper and lower stratum interface point sets, and is defined as a special grid node number.

[0139] Step 2.3: Determine whether there is data in the temporary number set. If so, execute step 2.4; otherwise, execute step 2.5.

[0140] Step 2.4: Select a grid node number in the temporary number set, define the grid node as MB, and classify the MB number into the upper or lower stratum interface point set according to the original connection relationship. The specific steps are as follows:

[0141] Step 2.4.1: According to the original connection relationship, all grid node numbers directly connected to the MB are screened, and non-special grid node numbers among the grid node numbers directly connected to the MB are classified into the screening number set.

[0142] Step 2.4.2: Determine whether there is a grid node number in the screening number set that belongs to the upper or lower stratum interface point set. If so, define the grid node as PB, and determine the ownership of the MB number based on the PB number, specifically:

[0143] If the number of PB belongs to the upper stratum interface point set, the number of MB is included in the set; otherwise, it is included in the lower stratum interface point set, and MB is removed from the temporary number set, and step 2.4.2 is ended directly;

[0144] If there is no PB, proceed to step 2.4.3.

[0145] Step 2.4.3: According to the original connection relationship, screen the numbers of all grid nodes directly connected to the grid nodes corresponding to all grid node numbers in the screening number set, and classify the non-special grid node numbers among them into the screening number set. According to whether there are new non-special grid node numbers included in the screening number set, select the execution content. If there are new non-special grid node numbers, return to step 2.4.2 directly; if not, remove MB directly from the temporary number set and end step 2.4.3.

[0146] Repeat step 2.4 until the temporary number set is empty.

[0147] Step 2.5: Obtain the boundary point number in the upper or lower stratum interface point set through the upper or lower stratum interface point set and the original connection relationship, and then determine the plane boundary of the set according to the original connection relationship. The specific steps are as follows:

[0148] Step 2.5.1: Filter out the grid node numbers that satisfy the boundary point rules from the upper or lower formation interface point set and define them as boundary point numbers; the boundary point rules include two points, and satisfying any one of the two points satisfies the boundary point rules, specifically: (1) the grid node number is a special grid node number; (2) the grid node number itself is a non-special grid node number located in the upper (or lower) formation interface point set, and according to the original connection relationship, there is a grid node number that is a non-special grid node number located in the lower (or upper) formation interface point set and is directly connected to it.

[0149] Step 2.5.2: Obtain all boundary point numbers, connect the boundary point numbers that are directly connected in the original connection relationship in sequence, and project them along the vertical direction to a fixed horizontal plane to obtain a boundary defined as the collective plane boundary.

[0150] Repeat steps 2.1 to 2.5 to establish a set of stratigraphic interface points and a set of plane boundaries for each geological body model.

[0151] The full model boundary of the three-dimensional geological model meets two requirements: (1) on a fixed horizontal plane, all the collective plane boundaries are not located outside the full model boundary; (2) when the previous requirement is met, the area contained in the full model boundary is the smallest.

[0152] Step 3: Define the formation type judgment rules, and determine the formation type as conventional formation, pinch-out formation or lens formation according to the collective plane boundary of the geological body model.

[0153] The formation type judgment rules are respectively lens formation rule and pinch-out formation rule.

[0154] The lens formation rule is that the collective plane boundary corresponding to the selected geological body model is completely within the boundary of the entire model.

[0155] The pinch-out stratum rule is that a portion of the set plane boundary corresponding to the selected geological body model is located within the boundary of the entire model, and a portion overlaps with the boundary of the entire model.

[0156] The determination of the formation type is specifically as follows: if the collective plane boundary corresponding to the selected geological body model satisfies the lens formation rule, then the formation type is defined as a lens formation; if the collective plane boundary corresponding to the selected geological body model satisfies the pinch-out formation rule, then the formation type is defined as a pinch-out formation; if neither is satisfied, then the formation type is defined as a conventional formation.

[0157] Step 4: According to the stratum interface point set and the original connection relationship of the geological body model, a new connection relationship is established to fuse the stratum interface point set, the top surface set, the bottom surface set and the lens set, and the grid node numbers in the set correspond to the grid nodes.

[0158] Step 4 is to establish a new connection relationship between the fused stratum interface point set, the top surface set, the bottom surface set and the lens set, and the grid node numbers in the set corresponding to the grid nodes. The specific steps are as follows:

[0159] Step 4.1: Select a stratum interface point set (upper or lower stratum interface point set) of a geological body model, and perform vertical interpolation projection on the grid nodes corresponding to each grid node number in the set to all stratum interface point sets of the remaining N-1 geological body models; record the stratum interface point set of the selected geological body model as the selected set, and establish a corresponding relationship between the two (establish a corresponding relationship between the selected set and the stratum interface point set of the selected geological body model); record the stratum interface point set of the projected geological body model as the projection set, and establish a corresponding relationship between the two (establish a corresponding relationship between the projection set and the stratum interface point set of the projected geological body model); when performing vertical interpolation projection, store the results separately according to the difference between the selected set and the projection set, and call them comparison sets, and the comparison sets correspond to both the selected set and the projection set.

[0160] The specific method of the vertical interpolation projection is to obtain points with the same horizontal coordinates X and Y as those of all grid node numbers corresponding to the selected set by spatial interpolation in the projection set; the spatial interpolation is Kriging spatial interpolation.

[0161] Step 4.2: Compare each selected set with the corresponding comparison set in turn. If there is a surface overlap relationship between the two, then record that the selected set corresponding to the comparison set overlaps with the projection set surface, and establish a fused stratigraphic interface point set, and determine whether to establish an independent set and its attributes.

[0162] The specific process of determining the overlap relationship of the face regions, establishing the fused stratum interface point set, and determining whether to establish an independent set and its attributes as described in step 4.2 is as follows:

[0163] Step 4.2.1: Establish a temporary fused formation interface point set corresponding to the transition of the comparison set; the transition correspondence refers to the simultaneous correspondence of the same selected set and projection set as the comparison set.

[0164] Step 4.2.2: Compare the selected set with the comparison set, and select the grid node numbers that meet the error overlap in the selected set, and store them in the temporary fused formation interface point set corresponding to the transition of the comparison set.

[0165] The grid node numbers that satisfy the error overlap are: the grid nodes corresponding to the grid node numbers in the selected set and the grid nodes corresponding to the grid node numbers in the comparison set satisfy the same horizontal coordinates X and Y, and the absolute value of the difference in vertical coordinate Z is less than the error ε1; the error ε1 is a fixed parameter set manually.

[0166] Step 4.2.3: Connect the grid nodes corresponding to the grid node numbers in the temporary fused stratigraphic interface point set that is not empty according to the original connection relationship. If a surface can be formed after the connection, it is recorded that the selected set corresponding to the temporary fused stratigraphic interface point set and the comparison projection set surface domain overlap.

[0167] Step 4.2.4: Determine whether all grid node numbers in the selected set are subsets of the union of all corresponding temporary fused formation interface point sets; if not, establish an independent set, and store the grid node numbers in the selected set that are not included in the union in the independent set, and determine their attributes based on the grid node numbers stored in the independent set; if so, do not establish an independent set.

[0168] Further, if the selected set does not have a corresponding temporary fused stratum interface point set, an independent set is established, and all grid node numbers of the selected set are stored in the independent set, and at the same time, its attributes are determined according to the grid node numbers stored in the independent set;

[0169] The independent set corresponds to the set of formation interface points corresponding to the selected set.

[0170] The attribute is determined according to the grid node numbers stored in the independent set, specifically: if the Z value of the grid nodes corresponding to all the grid node numbers in the independent set is greater than the Z value of the grid nodes with the same horizontal coordinate among the grid nodes corresponding to all the comparison set grid node numbers in the selected set, then the attribute of the independent set is defined as Top; if the Z value of the grid nodes corresponding to all the grid node numbers in the independent set is less than the Z value of the grid nodes with the same horizontal coordinate among the grid nodes corresponding to all the comparison set grid node numbers in the selected set, then the attribute of the independent set is defined as Down; otherwise, its attribute is defined as Mid.

[0171] Repeat until all the formation interface point sets of all geological models are selected as the set and all the operations in steps 4.1-4.2 are performed.

[0172] Step 4.3: Merge the temporary fused stratum interface point sets corresponding to the selected set and the projection set with the same inversion into one, and merge the corresponding relationship; then delete the temporary fused stratum interface point sets whose sets are empty and whose grid nodes corresponding to the grid node numbers in the sets cannot form a surface by connecting them according to the original connection relationship.

[0173] The inversion is the same means that the projection set corresponding to the temporary fusion formation interface point set A and the selected set corresponding to the temporary fusion formation interface point set B correspond to the same formation interface point set, and the selected set corresponding to the temporary fusion formation interface point set A and the projection set corresponding to the temporary fusion formation interface point set B correspond to the same formation interface point set.

[0174] The merged correspondence relationship refers to the transformation of the merged set into a fused formation interface point set, and directly corresponds to the selected set corresponding to the two temporary fused formation interface point sets and the formation interface point set corresponding to the projection set.

[0175] Step 4.4: Obtain the two corresponding formation interface point sets in the fused formation interface point set, recorded as a fused corresponding set pair, and then obtain the corresponding two geological body models. If there is a geological body model whose formation type is a lens formation, the fused formation interface point set is converted into an independent set, which corresponds to the formation interface point set corresponding to the lens formation in the fused corresponding set pair; the independent set attribute is Mid.

[0176] Step 4.5: Place all fused formation interface point sets and independent sets in the set group to be corrected, and perform correction on each set in the set group to be corrected.

[0177] Step 4.5 is to calibrate each set in the set to be calibrated. The specific process is as follows:

[0178] Step 4.5.1: Select a set from the set to be corrected as the set to be corrected, and obtain the spatial coordinates of the grid nodes corresponding to all the grid node numbers in the set.

[0179] Step 4.5.2: Obtain the interpolated vertical coordinates Z1 of the grid nodes corresponding to all grid node numbers in the set to be corrected through orthogonal test; solve the absolute value of the difference between the vertical coordinate Z of each grid node and the interpolated vertical coordinate Z1, and place the grid node numbers whose absolute values ​​are greater than the deviation ε2 in the set of nodes to be corrected, and place the remaining node numbers in the standard node set.

[0180] The orthogonal test described in step 4.5.2 obtains the interpolated vertical coordinate Z1 of the grid node, as follows:

[0181] Step 4.5.2a: Place all grid node numbers in the set to be corrected into the orthogonal test set;

[0182] Step 4.5.2b: Select a grid node corresponding to the grid node number in the orthogonal test set, record it as the node to be found, and remove its number from the orthogonal test set;

[0183] Step 4.5.2c: From the grid nodes corresponding to all grid node numbers in the orthogonal test set, obtain a point with the same horizontal coordinates as the node to be determined by spatial interpolation as an interpolation node; the vertical coordinate Z of the interpolation node is the interpolation vertical coordinate Z1 of the node to be determined.

[0184] The deviation ε2 described in step 4.5.2 is an artificially set fixed parameter.

[0185] Step 4.5.3: Perform an abnormality check on the grid nodes corresponding to the grid node numbers in the node set to be corrected. If the check result is abnormal, modify the value of the vertical coordinate Z of the grid node to the value of the interpolated vertical coordinate Z1; if the check result is not abnormal, maintain the value of the vertical coordinate Z of the grid node unchanged; repeat this step until all grid nodes corresponding to the grid node numbers in the node set to be corrected have been checked for abnormalities.

[0186] The deformity examination described in step 4.5.3 is as follows:

[0187] Step 4.5.3a: Select a grid node number from the set of nodes to be corrected; obtain the grid node corresponding to the grid node number, and record it as the node to be checked;

[0188] Step 4.5.3b: Obtain multiple grid node numbers from the standard node set that can uniquely surround the node to be inspected in the minimum horizontal plane or the minimum inner angle uniquely surround the node to be inspected, and record them as the standard node group;

[0189] The minimum unique encirclement of the node to be inspected within the plane range satisfies that the projection of the grid nodes corresponding to the multiple grid node numbers in the standard node set to the fixed horizontal plane after connection can enclose a polygon by itself, and the polygon does not contain the projections of the grid nodes corresponding to all the grid node numbers in the standard node set in the fixed horizontal plane, but contains the projection of the node to be inspected, and the number of sides of the polygon is the smallest, and the area of ​​the polygon is the smallest;

[0190] The large inner angle minimum unique surrounding node to be inspected means that, when the polygon formed by connecting the grid nodes corresponding to any multiple grid node numbers in the standard node set and projecting onto a fixed horizontal plane cannot contain the projection of the node to be inspected, multiple grid nodes corresponding to the grid node numbers in the standard node set are selected and connected to the node to be inspected, and the projection onto the fixed horizontal plane can form a polygon, the polygon does not contain the projections of the grid nodes corresponding to all the grid node numbers in the standard node set in the fixed horizontal plane, and the inner angle corresponding to the projection of the node to be inspected is the largest, the number of sides of the polygon is the smallest, and the area of ​​the polygon is the smallest;

[0191] Step 4.5.3c: Solve the average node of the standard node group in space, and solve the average distance between the standard node group and the average node in space, recorded as La; solve the distance Lb between the node to be tested and the average node in space; if Lb / La is greater than the aspect ratio, return that the node to be tested is deformed, otherwise return that it is not deformed.

[0192] The X, Y and Z of the average node in step 4.5.3c are equal to the average values ​​of the X, Y and Z of the grid nodes corresponding to all grid node numbers in the standard node group; the slenderness ratio is a fixed parameter set manually.

[0193] Step 4.5.4: Clear the node set to be corrected, and remove the selected set to be corrected from the set group to be corrected.

[0194] Repeat steps 4.5.1-4.5.4 until the set to be corrected is empty.

[0195] Step 4.6: Repair and fuse the stratum interface point set, and establish a new connection relationship in which the grid node numbers correspond to the grid nodes.

[0196] Step 4.6 repairs and fuses the stratum interface point set, and establishes a new connection relationship in which the grid node number corresponds to the grid node, as follows:

[0197] Step 4.6.1: Select a set of fused stratigraphic interface points, and connect the grid nodes corresponding to the grid node numbers in the set according to the original connection relationship to form two grid surfaces; extract the contours of the two grid surfaces, the grid node numbers on the contours and their original connection relationships, and record them as old contours, old contour node numbers and old contour connection relationships.

[0198] Step 4.6.2: Project the old contour along the vertical direction onto a fixed horizontal plane to obtain a new contour projection that can just surround the old contour projection in the fixed horizontal plane.

[0199] Step 4.6.3: Obtain the old contour node number corresponding to the new contour projection as the new contour node number, and determine whether it is necessary to add a new grid node and its corresponding number and the original connection relationship; if it is necessary to add, store the newly added grid node number in the selected fusion stratigraphic interface point set, and use the newly added grid node number as the new contour node number; according to the connection relationship of the new contour projection vertices, add the connection relationship between the newly added grid node and the existing grid node to the original connection relationship.

[0200] Step 4.6.3 determines whether a new grid node needs to be added and its corresponding number and original connection relationship, as follows:

[0201] Step 4.6.3a: Determine whether there is an intersection between the two old contour projections, and the intersection does not coincide with the projection point of the grid node corresponding to the old contour node number; if so, it is necessary to add a new grid node with the same horizontal coordinate as the intersection, and assign it a number that is different from the existing grid node numbers, and execute step 4.6.3b; if not, it does not need to be added, and end;

[0202] Step 4.6.3b: Get the edge of the old contour corresponding to the projection of the old contour that forms the intersection, obtain the points on the two old contour edges with the same horizontal coordinates as the intersection through linear interpolation, and solve the average value of the vertical coordinates Z of the two points as the value of the vertical coordinate Z of the newly added grid node.

[0203] Step 4.6.4: Determine whether the newly added grid node number needs to be stored in the unselected fused stratum interface point set or the independent set with the attribute Mid. If necessary, store the newly added grid node number in the unselected fused stratum interface point set or the independent set with the attribute Mid.

[0204] Step 4.6.4 determines whether the newly added grid node number needs to be stored in the unselected fused stratum interface point set or the independent set with the attribute Mid, as follows:

[0205] Step 4.6.4a: Search for the unselected fused stratum interface point set corresponding to the same stratum interface point set as the selected fused stratum interface point set and the independent set with the attribute of Mid;

[0206] Step 4.6.4b: Connect the unselected fused stratum interface point set described in 4.6.4a and the grid nodes corresponding to the grid node numbers in the independent set with the attribute Mid according to the original connection relationship to form at least one grid surface SA, and project it onto a fixed horizontal plane along the vertical direction;

[0207] Step 4.6.4c: If the point where the newly added grid node is projected onto the fixed horizontal plane along the vertical direction is located on the contour of the projection of a certain grid surface SA, the number of the newly added grid node is stored in the corresponding unselected fused formation interface point set described in 4.6.4a or in an independent set with the attribute Mid.

[0208] Step 4.6.5: If there are spatially similar points in the grid nodes corresponding to the grid node numbers in the selected fused formation interface point set, only the number of one of the points is retained in the set, and the numbers of the remaining points are discarded; the grid nodes are spatially similar when the spatial distance between the grid nodes is less than the distance difference ε3; the distance difference ε3 is an artificially set fixed parameter.

[0209] Step 4.6.6: Using the new contour projection as the boundary and in accordance with the triangulated network restricted growth principle, establish a new connection relationship between the grid node numbers corresponding to the grid nodes in the selected fused stratum interface point set.

[0210] The method described in step 4.6.6 uses the new contour projection as the boundary and follows the triangulated network restricted growth principle, which means that the mesh nodes corresponding to the mesh node numbers in the fused stratum interface point set are connected according to the new connection relationship to meet the following requirements: (1) All meshes are triangular meshes and the mesh nodes corresponding to all mesh node numbers in the set are vertices of triangles; (2) The range of all meshes after projection onto a fixed horizontal plane does not exceed the new contour projection; and (3) There is no overlap or intersection between the projections of all triangular meshes onto the fixed horizontal plane.

[0211] Step 4.7: Obtain all independent sets with the attribute Mid, establish c lens sets and their new connection relationships; where c≥0.

[0212] Step 4.7 describes the establishment of c lens sets. The specific process is as follows:

[0213] Step 4.7.1: Select an independent set with the attribute Mid, called the independent set NA, and select all independent sets that can correspond to the same geological body model across sets with the independent set NA from the remaining independent sets with the attribute Mid, called the independent set group NB.

[0214] Step 4.7.2: According to the number of formation interface point sets corresponding to the independent set NA, establish the same number of temporary lens sets, copy all the grid node numbers in the independent set NA to all temporary lens sets, and during each copying process, pass the corresponding relationship of a formation interface point set of the independent set NA to the temporary lens set.

[0215] Step 4.7.3: In the independent set group NB, select the independent set NC that can correspond to the same geological body model as the temporary lens set across the set, copy all the grid node numbers in the independent set NC to the temporary lens set, and pass a formation interface point set correspondence relationship of the independent set NC to the temporary lens set.

[0216] The corresponding relationship of the formation interface point set transmitted by the independent set NC satisfies that the formation interface point set in the corresponding relationship and the formation interface point set corresponding to the temporary lens set correspond to the same geological body model.

[0217] The independent set transfers the corresponding relationship between the stratum interface point set to the temporary lens set, which means deleting the corresponding relationship between the independent set and the stratum interface point set, and establishing the corresponding relationship between the temporary lens set and the stratum interface point set.

[0218] The cross-set correspondence means that there is at least one identical one in all geological body models corresponding to one of the stratum interface point sets corresponding to the independent sets.

[0219] Furthermore, after the transfer described in steps 4.7.2 and 4.7.3 is completed, the independent set is immediately judged, and if the independent set no longer corresponds to any formation interface point set, the independent set is deleted.

[0220] Repeat steps 4.7.1-4.7.3 until all independent sets with the attribute Mid are deleted.

[0221] Step 4.7.4: Keep the storage content and corresponding relationship of the temporary lens set unchanged, and convert the temporary lens set into a lens set.

[0222] Step 4.7.5: According to the lens triangle mesh growth principle, establish new connection relationships for all lens sets.

[0223] The lens triangular mesh growth principle described in step 4.7.5 satisfies the following requirements: (1) all meshes are triangular meshes and all mesh nodes corresponding to the mesh node numbers in the set are vertices of triangles; (2) the meshes can be enclosed into a unique closed space.

[0224] Step 4.8: Obtain all independent sets with the attributes of Top and Down, and establish a top surface set and b bottom surface sets; a≥1, b≥1.

[0225] Step 4.8 creates a top surface set and b bottom surface sets. The specific process is as follows:

[0226] Step 4.8.1: Select an independent set with the attribute of Top or Down, recorded as the independent set ND, obtain the formation interface point set corresponding to the independent set ND, recorded as the formation interface point set C, and then obtain all the fused formation interface point sets corresponding to the formation interface point set, recorded as the fused formation interface point set C'.

[0227] Step 4.8.2: Connect the grid nodes corresponding to the grid node numbers in the formation interface point set C according to the original connection relationship to obtain the grid surface SB; connect the grid nodes corresponding to the grid node numbers in the fused formation interface point set C' according to the new connection relationship to obtain the grid surface SC; project the contours of the grid surfaces SB and SC onto a fixed horizontal plane at the same time, obtain the part of the contour projection of the grid surface SC that does not overlap with the contour projection of the grid surface SB, and store the grid node numbers corresponding to the non-overlapping parts in different grid boundary groups according to the new connection relationship.

[0228] The mesh node numbers in the mesh boundary group meet the requirements and can form a line after being connected according to the new connection relationship.

[0229] Step 4.8.3: Store the mesh node numbers in the mesh boundary group that meets the independent set integration relationship into the selected independent set.

[0230] The mesh boundary group that satisfies the integration into the independent set relationship described in step 4.8.3 refers to the following: the triangular mesh formed by connecting the mesh nodes corresponding to the mesh numbers in the mesh boundary group with the mesh nodes corresponding to any two mesh node numbers in the independent set cannot overlap with the projection of the mesh surface SC along the vertical direction to the fixed horizontal plane.

[0231] Step 4.8.4: Establish a new connection relationship for the independent set. The new connection relationship meets the following requirements: the mesh surface formed by connecting the mesh nodes corresponding to the mesh node numbers in the independent set according to the new connection relationship will not exceed the projection of the mesh surface SB contour when projected onto the fixed horizontal plane in the vertical direction, and will not overlap with the projection of the mesh surface SC, and they are all triangular meshes.

[0232] Step 4.8.5: Convert the independent set to a top surface set or a bottom surface set according to its attribute. Specifically, if the attribute is Top, convert it to a top surface set; if the attribute is Down, convert it to a bottom surface set.

[0233] Furthermore, if the fused stratum interface point set C' is not obtained in step 4.8.1, step 4.8.5 is directly executed.

[0234] Step 5: Generate a model by reconstruction in CAE software according to the mesh node numbers, spatial coordinates and new connection relationships of the mesh nodes.

[0235] The model generated by reconstruction in the CAE software described in step 5 is specifically as follows:

[0236] Step 5.1: Generate mesh nodes corresponding to all mesh node numbers in the fusion interface point set, top surface set, bottom surface set and lens set in the CAE software.

[0237] Step 5.2: Select a geological body model of non-lens stratum type, obtain the fused interface point set, top surface set or bottom surface set corresponding to its upper and lower stratum interface point sets, and connect them in the CAE platform according to the new connection relationship to form two grid surfaces corresponding to the upper and lower stratum interface point sets, which are recorded as the upper and lower grid surfaces of the geological body respectively.

[0238] Step 5.3: Through the stretching operation of the CAE platform, the upper / lower grid surface of the geological body is stretched downward / upward to the lower / upper grid surface to form a CAE model corresponding to the geological body model.

[0239] Repeat steps 5.2-5.3 until the corresponding CAE models of all non-lens formation geological models are established.

[0240] Step 5.4: Select the geological body model of lens strata, obtain its corresponding lens set, and form a closed body in the CAE platform according to the new connection relationship, which is the CAE model corresponding to the geological body model; repeat this step to establish CAE models of all lens strata.

[0241] Step 5.5: In the CAE platform, the CAE model of the lenticular formation is subtracted from the CAE model of the non-lenticular formation through Boolean operation; the CAE model after the Boolean operation and the CAE model of the lenticular formation together constitute the CAE model of the three-dimensional geological model.

[0242] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for automatically converting a three-dimensional geological model into a finite element model, characterized in that: The following steps are involved: Step 1: Obtain the grid nodes of each geological body model in the three-dimensional geological model and the original connection relationship of the grid nodes; the grid nodes include their numbers and spatial coordinates; the spatial coordinates include horizontal coordinates X, horizontal coordinates Y and vertical coordinates Z; the original connection relationship of the grid nodes is: the grid nodes are connected to each other according to the original connection relationship to form multiple grid surfaces, and the multiple grid surfaces can surround and form a complete geological body model. The number of geological body models is N, N≥1, and N geological body models are combined into a three-dimensional geological model; Step 2: Establish a stratum interface point set and a corresponding set plane boundary of each geological body model; establish a full model boundary of a three-dimensional geological model; the stratum interface point set includes an upper stratum interface point set and a lower stratum interface point set; Step 3: Define the formation type judgment rule, and determine the formation type as conventional formation, pinch-out formation or lens formation according to the collective plane boundary of the geological body model; Step 4: According to the stratum interface point set and the original connection relationship of the geological body model, a fused stratum interface point set, a top surface set, a bottom surface set and a lens set are established, and a new connection relationship between the grid node numbers in each set and the grid nodes is established; Step 5: Generate a CAE model by reconstruction in the CAE software according to the mesh node numbers, spatial coordinates and new connection relationships of the mesh nodes.

2. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 1, characterized in that: The step 2 is to establish a set of stratum interface points and a corresponding set plane boundary of each geological body model. The specific process is as follows: Step 2.1: Select a geological body model and obtain its grid nodes; Step 2.2: Project each grid node vertically onto the geological model in turn, and classify the grid node numbers into upper and lower stratum interface point sets and temporary number sets according to the projection relationship, as follows: If the number of projection points p obtained by projecting the grid node is greater than one, and the grid node coincides with the projection point p with the largest vertical coordinate Z, the grid node number is classified into the upper stratum interface point set; if the number of projection points p obtained by projecting the grid node is greater than one, and the grid node coincides with the projection point p with the smallest vertical coordinate Z, the grid node number is classified into the lower stratum interface point set; if the number of projection points p obtained by projecting the grid node is greater than one, and the grid node does not coincide with the projection point p with the largest and smallest vertical coordinates Z, the grid node number is classified into the temporary number set; if the number of projection points p obtained by projecting the grid node is equal to one, the grid node number is classified into both the upper and lower stratum interface point sets, and is defined as a special grid node number; Step 2.3: Determine whether there is data in the temporary number set. If so, execute step 2.4; otherwise, execute step 2.

5. Step 2.4: Select a grid node number in the temporary number set, define the grid node as MB, and classify the MB number into the upper or lower stratum interface point set according to the original connection relationship. The specific steps are as follows: Step 2.4.1: According to the original connection relationship, all grid node numbers directly connected to the MB are screened, and non-special grid node numbers among the grid node numbers directly connected to the MB are classified into the screening number set; Step 2.4.2: Determine whether there is a grid node number in the screening number set that belongs to the upper or lower stratum interface point set. If so, define the grid node as PB, and determine the ownership of the MB number based on the PB number, specifically: If the number of PB belongs to the upper stratum interface point set, the number of MB is included in the set; otherwise, it is included in the lower stratum interface point set, and MB is removed from the temporary number set, and step 2.4.2 is terminated directly; if there is no PB, step 2.4.3 is executed; Step 2.4.3: According to the original connection relationship, screen all the grid node numbers directly connected to the grid nodes corresponding to all the grid node numbers in the screening number set, and classify the non-special grid node numbers therein into the screening number set. Select the execution content according to whether there are new non-special grid node numbers included in the screening number set. If there are, directly return to step 2.4.2; if not, directly remove MB from the temporary number set and end step 2.4.3; Repeat step 2.4 until the temporary number set is empty; Step 2.5: Obtain the boundary point number in the upper or lower stratum interface point set through the upper or lower stratum interface point set and the original connection relationship, and then determine the plane boundary of the set according to the original connection relationship. The specific steps are as follows: Step 2.5.1: Filter out the grid node numbers that meet the boundary point rule from the upper or lower stratum interface point set, and define them as boundary point numbers; the boundary point rule includes two points, and satisfying any one of the points satisfies the boundary point rule, specifically: (1) the grid node number is a special grid node number; (2) the grid node number itself is a non-special grid node number located in the upper or lower stratum interface point set, and according to the original connection relationship, there is a grid node number that is a non-special grid node number located in the lower or upper stratum interface point set and is directly connected to it; Step 2.5.2: Obtain all boundary point numbers, connect the boundary point numbers that are directly connected in the original connection relationship in sequence, and project them along the vertical direction to a fixed horizontal plane to obtain a boundary defined as the collective plane boundary; Repeat steps 2.1 to 2.5 to establish a set of stratum interface points and a set plane boundary for each geological body model; The full model boundary of the three-dimensional geological model meets two requirements: (1) on a fixed horizontal plane, all the collective plane boundaries are not located outside the full model boundary; (2) when the previous requirement is met, the area contained in the full model boundary is the smallest.

3. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 1, characterized in that: The formation type judgment rules in step 3 are lens formation rule and pinch-out formation rule respectively; the lens formation rule is that the set plane boundary corresponding to the selected geological body model is completely within the boundary of the whole model; the pinch-out formation rule is that the set plane boundary corresponding to the selected geological body model is partially within the boundary of the whole model and partially overlaps with the boundary of the whole model; The determination of the formation type is specifically as follows: if the collective plane boundary corresponding to the selected geological body model satisfies the lens formation rule, then the formation type is defined as a lens formation; if the collective plane boundary corresponding to the selected geological body model satisfies the pinch-out formation rule, then the formation type is defined as a pinch-out formation; if neither is satisfied, then the formation type is defined as a conventional formation.

4. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 1, characterized in that: Step 4 is to establish a fusion stratum interface point set, a top surface set, a bottom surface set and a lens set, and to establish a new connection relationship between the grid node numbers in the set and the grid nodes. The specific steps are as follows: Step 4.1: Select an upper or lower stratum interface point set of a geological body model, and perform vertical interpolation projection on the grid nodes corresponding to each grid node number in the set to all stratum interface point sets of the remaining N-1 geological body models; record the stratum interface point set of the selected geological body model as the selected set, and establish a corresponding relationship between the two; record the stratum interface point set of the projected geological body model as the projection set, and establish a corresponding relationship between the two; when performing vertical interpolation projection, store the results separately according to the difference between the selected set and the projection set, and call them the comparison set, which corresponds to the selected set and the projection set at the same time; Step 4.2: Compare each selected set with the corresponding comparison set in turn. If there is a surface overlap relationship between the two sets, then record that the selected set corresponding to the comparison set overlaps with the projection set surface, and establish a fused stratum interface point set. At the same time, determine whether to establish an independent set and its attributes; The specific process of step 4.2 is as follows: Step 4.2.1: Establishing a temporary fused stratum interface point set corresponding to the transition of the comparison set; the transition correspondence means that the selected set and the projection set are simultaneously corresponding to the same set as the comparison set; Step 4.2.2: Compare the selected set with the comparison set, and select the grid node numbers that meet the error overlap in the selected set, and store them in the temporary fused formation interface point set corresponding to the transition of the comparison set; The grid node numbers satisfying the error overlap are: the grid nodes corresponding to the grid node numbers in the selected set and the grid nodes corresponding to the grid node numbers in the comparison set satisfy the same horizontal coordinates X and Y, and the absolute value of the difference in vertical coordinate Z is less than the error ε1; Step 4.2.3: Connect the grid nodes corresponding to the grid node numbers in the temporary fused stratum interface point set that is not empty according to the original connection relationship. If a surface can be formed after the connection, it is recorded that the selected set corresponding to the temporary fused stratum interface point set and the comparison projection set surface domain coincide with each other; Step 4.2.4: Determine whether all grid node numbers in the selected set are subsets of the union of all corresponding temporary fused stratum interface point sets; if not, establish an independent set, and store the grid node numbers in the selected set that are not included in the union in the independent set, and determine their attributes according to the grid node numbers stored in the independent set; If so, no independent set is created; If the selected set does not have a corresponding temporary fused stratum interface point set, an independent set is established, and all grid node numbers of the selected set are stored in the independent set, and at the same time, its attributes are determined according to the grid node numbers stored in the independent set; The independent set corresponds to the set of stratum interface points corresponding to the selected set; The method of determining the attribute of the independent set according to the grid node numbers stored in the independent set is as follows: if the Z value of the grid nodes corresponding to all the grid node numbers in the independent set is greater than the Z value of the grid nodes with the same horizontal coordinate among the grid nodes corresponding to all the comparison set grid node numbers in the selected set, then the attribute of the independent set is defined as Top; if the Z value of the grid nodes corresponding to all the grid node numbers in the independent set is less than the Z value of the grid nodes with the same horizontal coordinate among the grid nodes corresponding to all the comparison set grid node numbers in the selected set, then the attribute of the independent set is defined as Down; otherwise, the attribute is defined as Mid; Repeat until all the formation interface point sets of all geological body models are selected as the set to perform all the operations of steps 4.1-4.2; Step 4.3: merge the temporary fused stratum interface point sets corresponding to the selected set and the projection set with the same inversion into one, and merge the corresponding relationship; then delete the temporary fused stratum interface point sets whose sets are empty and whose grid nodes corresponding to the grid node numbers in the sets cannot form a surface by connecting them according to the original connection relationship; Step 4.4: Obtain two corresponding formation interface point sets in the fused formation interface point set, record them as a fused corresponding set pair, and then obtain two corresponding geological body models. If there is a geological body model whose formation type is a lens formation, then convert the fused formation interface point set into an independent set, which corresponds to the formation interface point set corresponding to the lens formation in the fused corresponding set pair; the independent set attribute is Mid; Step 4.5: Place all fused formation interface point sets and independent sets in the set group to be corrected, and correct each set in the set group to be corrected; Step 4.6: patch and fuse the stratum interface point set, and establish a new connection relationship in which the grid node numbers correspond to the grid nodes; Step 4.7: Obtain all independent sets with the attribute Mid, establish c lens sets and their new connection relationships; where c≥0; Step 4.8: Obtain all independent sets with the attributes of Top and Down, and establish a top surface set and b bottom surface sets; a≥1, b≥1.

5. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 4, characterized in that: In step 4.1, the specific method of the vertical interpolation projection is: obtaining points with the same horizontal coordinates X and Y as those of all grid node numbers corresponding to the selected set by spatial interpolation in the projection set; In step 4.3, the inversion is the same means that the projection set corresponding to the temporary fusion formation interface point set A and the selected set corresponding to the temporary fusion formation interface point set B correspond to the same formation interface point set, and the selected set corresponding to the temporary fusion formation interface point set A and the projection set corresponding to the temporary fusion formation interface point set B correspond to the same formation interface point set; In step 4.3, the merged correspondence refers to the transformation of the merged set into a fused formation interface point set, and directly corresponds to the selected set corresponding to the two temporary fused formation interface point sets and the formation interface point set corresponding to the projection set.

6. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 4, characterized in that: Step 4.5 is to calibrate each set in the set to be calibrated. The specific process is as follows: Step 4.5.1: Select a set from the set to be corrected as the set to be corrected, and obtain the spatial coordinates of the grid nodes corresponding to the grid node numbers in the set; Step 4.5.2: Obtain the interpolated vertical coordinates Z1 of the grid nodes corresponding to all grid node numbers in the set to be corrected through orthogonal test; solve the absolute value of the difference between the vertical coordinate Z of each grid node and the interpolated vertical coordinate Z1, and place the grid node numbers whose absolute values ​​are greater than the deviation ε2 in the set of nodes to be corrected, and place the remaining node numbers in the standard node set; The orthogonal test described in step 4.5.2 obtains the interpolated vertical coordinate Z1 of the grid node, as follows: Step 4.5.2a: Place all grid node numbers in the set to be corrected into the orthogonal test set; Step 4.5.2b: Select a grid node corresponding to the grid node number in the orthogonal test set, record it as the node to be found, and remove its number from the orthogonal test set; Step 4.5.2c: Obtain a point with the same horizontal coordinate as the node to be determined from among the grid nodes corresponding to all grid node numbers in the orthogonal test set by spatial interpolation as an interpolation node; the vertical coordinate Z of the interpolation node is the interpolation vertical coordinate Z1 of the node to be determined; Step 4.5.3: Perform a deformity check on the grid node corresponding to the grid node number in the set of nodes to be corrected. If the check result is deformity, the value of the vertical coordinate Z of the grid node is modified to the value of the interpolated vertical coordinate Z1; if the check result is not deformity, the value of the vertical coordinate Z of the grid node is maintained unchanged; Repeat this step until all grid nodes corresponding to the grid node numbers in the set of nodes to be corrected have been inspected for deformity; The deformity examination described in step 4.5.3 is as follows: Step 4.5.3a: Select a grid node number from the set of nodes to be corrected; obtain the grid node corresponding to the grid node number, and record it as the node to be checked; Step 4.5.3b: Obtain multiple grid node numbers from the standard node set that can uniquely surround the node to be inspected in the minimum horizontal plane or the minimum inner angle uniquely surround the node to be inspected, and record them as the standard node group; The minimum unique encirclement of the node to be inspected within the plane range satisfies that the projection of the grid nodes corresponding to the multiple grid node numbers in the standard node set to the fixed horizontal plane after connection can enclose a polygon by itself, and the polygon does not contain the projections of the grid nodes corresponding to all the grid node numbers in the standard node set in the fixed horizontal plane, but contains the projection of the node to be inspected, and the number of sides of the polygon is the smallest, and the area of ​​the polygon is the smallest; The large inner angle minimum unique surrounding node to be inspected means that, when the polygon formed by connecting the grid nodes corresponding to any multiple grid node numbers in the standard node set and projecting onto a fixed horizontal plane cannot contain the projection of the node to be inspected, multiple grid nodes corresponding to the grid node numbers in the standard node set are selected and connected to the node to be inspected, and the projection onto the fixed horizontal plane can form a polygon, the polygon does not contain the projections of the grid nodes corresponding to all the grid node numbers in the standard node set in the fixed horizontal plane, and the inner angle corresponding to the projection of the node to be inspected is the largest, the number of sides of the polygon is the smallest, and the area of ​​the polygon is the smallest; Step 4.5.3c: Solve the average node of the standard node group in space, and solve the average distance between the standard node group and the average node in space, recorded as La; solve the distance Lb between the node to be tested and the average node in space; if Lb / La is greater than the slenderness ratio, return that the node to be tested is deformed, otherwise return that it is not deformed; The X, Y and Z of the average node are equal to the average values ​​of the X, Y and Z of the grid nodes corresponding to all grid node numbers in the standard node group; the slenderness ratio is a set parameter; Step 4.5.4: Clear the node set to be corrected, and remove the selected set to be corrected from the set group to be corrected; Repeat steps 4.5.1-4.5.4 until the set to be corrected is empty.

7. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 4, characterized in that: Step 4.6 repairs and fuses the stratum interface point set, and establishes a new connection relationship in which the grid node number corresponds to the grid node, as follows: Step 4.6.1: Select a fusion formation interface point set, connect the grid nodes corresponding to the grid node numbers in the set according to the original connection relationship to form two grid surfaces; extract the contours of the two grid surfaces, the grid node numbers on the contours and their original connection relationships, and record them as old contours, old contour node numbers and old contour connection relationships; Step 4.6.2: Project the old contour along the vertical direction onto a fixed horizontal plane to obtain a new contour projection that can just surround the old contour projection in the fixed horizontal plane; Step 4.6.3: Obtain the old contour node number corresponding to the new contour projection as the new contour node number, and determine whether it is necessary to add a new grid node and its corresponding number and original connection relationship; if it is necessary to add, store the newly added grid node number in the selected fusion stratum interface point set, and use the newly added grid node number as the new contour node number; according to the connection relationship of the new contour projection vertices, add the connection relationship between the newly added grid node and the existing grid node to the original connection relationship; Step 4.6.3 determines whether a new grid node needs to be added and its corresponding number and original connection relationship, as follows: Step 4.6.3a: Determine whether there is an intersection between the two old contour projections, and the intersection does not coincide with the projection point of the grid node corresponding to the old contour node number; if so, it is necessary to add a new grid node with the same horizontal coordinate as the intersection, and assign it a number that is different from the existing grid node numbers, and execute step 4.6.3b; if not, it does not need to be added, and end; Step 4.6.3b: Get the edge of the old contour corresponding to the projection of the old contour that forms the intersection, obtain the points on the two old contour edges with the same horizontal coordinates as the intersection through linear interpolation, and solve the average value of the vertical coordinates Z of the two points as the value of the vertical coordinate Z of the newly added grid node; Step 4.6.4: Determine whether the newly added grid node number needs to be stored in the unselected fused stratum interface point set or the independent set with the attribute Mid at the same time. If necessary, store the newly added grid node number in the unselected fused stratum interface point set or the independent set with the attribute Mid. Step 4.6.4 determines whether the newly added grid node number needs to be stored in the unselected fused stratum interface point set or the independent set with the attribute Mid, as follows: Step 4.6.4a: Search for the unselected fused stratum interface point set corresponding to the same stratum interface point set as the selected fused stratum interface point set and the independent set with the attribute of Mid; Step 4.6.4b: connect the unselected fused stratum interface point set in step 4.6.4a and the grid nodes corresponding to the grid node numbers in the independent set with the attribute Mid according to the original connection relationship to form at least one grid surface SA, and project it onto a fixed horizontal plane along the vertical direction; Step 4.6.4c: If the point where the newly added grid node is projected onto the fixed horizontal plane along the vertical direction is located on the contour of the projection of a certain grid surface SA, the number of the newly added grid node is stored in the corresponding unselected fused stratum interface point set described in 4.6.4a or in the independent set with the attribute Mid; Step 4.6.5: If there are points that are spatially close to the grid nodes corresponding to the grid node numbers in the selected fused stratum interface point set, only the number of one of the points is retained in the set, and the numbers of the remaining points are discarded; the grid nodes are spatially close means that the spatial distance between the grid nodes is less than the distance difference ε3; the distance difference ε3 is an artificially set fixed parameter; Step 4.6.6: Using the new contour projection as the boundary and in accordance with the triangulated network restricted growth principle, establish a new connection relationship between the grid node numbers and the grid nodes in the selected fused stratum interface point set; The method of taking the new contour projection as the boundary and restricting the growth of the triangulated network according to the principle of limiting the growth of the triangulated network means that the grid nodes corresponding to the grid node numbers in the fused stratum interface point set are connected according to the new connection relationship to meet the following requirements: (1) all grids are triangular grids and the grid nodes corresponding to all grid node numbers in the set are vertices of triangles; (2) the range of all grids after being projected onto a fixed horizontal plane does not exceed the projection of the new contour; and (3) the projections of all triangular grids onto the fixed horizontal plane do not overlap or intersect with each other.

8. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 4, characterized in that: Step 4.7 describes the establishment of c lens sets. The specific process is as follows: Step 4.7.1: Select an independent set with the attribute Mid, called the independent set NA, and select all independent sets that can correspond to the same geological body model across sets with the independent set NA from the other independent sets with the attribute Mid, called the independent set group NB; Step 4.7.2: According to the number of formation interface point sets corresponding to the independent set NA, establish temporary lens sets with the same number, copy all grid node numbers in the independent set NA to all temporary lens sets, and during each copying process, simultaneously transfer a formation interface point set correspondence relationship of the independent set NA to the temporary lens set; Step 4.7.3: In the independent set group NB, select the independent set NC that can correspond to the same geological body model as the temporary lens set across the set, copy all grid node numbers in the independent set NC to the temporary lens set, and transfer a formation interface point set correspondence relationship of the independent set NC to the temporary lens set; The corresponding relationship between the formation interface point sets transmitted by the independent set NC satisfies that the formation interface point set in the corresponding relationship and the formation interface point set corresponding to the temporary lens set correspond to the same geological body model; The independent set transfers the corresponding relationship between the stratum interface point set to the temporary lens set, which means deleting the corresponding relationship between the independent set and the stratum interface point set, and establishing the corresponding relationship between the temporary lens set and the stratum interface point set; The cross-set correspondence means that there is at least one identical one in all geological body models corresponding to one of the stratum interface point sets corresponding to the independent sets; After the transfer in steps 4.7.2 and 4.7.3 is completed, the independent set is immediately judged. If the independent set no longer corresponds to any formation interface point set, the independent set is deleted; Repeat steps 4.7.1-4.7.3 until all independent sets with the attribute Mid are deleted; Step 4.7.4: Keep the storage content and corresponding relationship of the temporary lens set unchanged, and convert the temporary lens set into a lens set; Step 4.7.5: According to the lens triangle mesh growth principle, establish a new connection relationship for all lens sets; The lens triangular mesh growth principle described in step 4.7.5 satisfies the following requirements: (1) all meshes are triangular meshes and all mesh nodes corresponding to the mesh node numbers in the set are vertices of triangles; (2) the meshes can be enclosed into a unique closed space.

9. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 4, characterized in that: Step 4.8 creates a top surface set and b bottom surface sets. The specific process is as follows: Step 4.8.1: Select an independent set with the attribute of Top or Down, recorded as the independent set ND, obtain the formation interface point set corresponding to the independent set ND, recorded as the formation interface point set C, and then obtain all the fused formation interface point sets corresponding to the formation interface point set, recorded as the fused formation interface point set C'; Step 4.8.2: Connect the grid nodes corresponding to the grid node numbers in the stratum interface point set C according to the original connection relationship to obtain the grid surface SB; connect the grid nodes corresponding to the grid node numbers in the fused stratum interface point set C' according to the new connection relationship to obtain the grid surface SC; Project the contours of the mesh surfaces SB and SC onto a fixed horizontal plane at the same time, obtain the part of the contour projection of the mesh surface SC that does not overlap with the contour projection of the mesh surface SB, and store the mesh node numbers corresponding to the non-overlapping parts in different mesh boundary groups according to the new connection relationship; The grid node numbers in the grid boundary group meet the requirement that a line can be formed after being connected according to the new connection relationship; Step 4.8.3: storing the numbers of the grid nodes in the grid boundary group that satisfy the integration into the independent set relationship into the selected independent set; The said satisfying integration into the independent set relationship refers to a mesh boundary group: the triangular mesh formed by connecting the mesh nodes corresponding to the mesh node numbers in the mesh boundary group with the mesh nodes corresponding to any two mesh node numbers in the independent set cannot overlap with the projection of the mesh surface SC along the vertical direction to the fixed horizontal plane; Step 4.8.4: Establish a new connection relationship for the independent set, and the new connection relationship meets the following requirements: the mesh surface formed by connecting the mesh nodes corresponding to the mesh node numbers in the independent set according to the new connection relationship will not exceed the projection of the mesh surface SB contour along the vertical direction to the fixed horizontal plane, and will not overlap with the projection of the mesh surface SC, and all of them are triangular meshes; Step 4.8.5: Convert the independent set to a top surface set or a bottom surface set according to its attribute. Specifically, if the attribute is Top, convert it to a top surface set; if the attribute is Down, convert it to a bottom surface set. If the fused stratum interface point set C' is not obtained in step 4.8.1, directly execute step 4.8.

5.

10. The method for automatically converting a three-dimensional geological model into a finite element model according to claim 1, characterized in that: Step 5 generates a CAE model by reconstruction in the CAE software, as follows: Step 5.1: Generate mesh nodes corresponding to all mesh node numbers in the fusion interface point set, top surface set, bottom surface set and lens set in the CAE software; Step 5.2: Select a geological body model of non-lens stratum type, obtain the fused interface point set, top surface set or bottom surface set corresponding to the upper and lower stratum interface point sets, and connect them in the CAE platform according to the new connection relationship to form two grid surfaces corresponding to the upper and lower stratum interface point sets, which are recorded as the upper and lower grid surfaces of the geological body respectively; Step 5.3: Through the stretching operation of the CAE platform, the upper / lower grid surface of the geological body is stretched downward / upward to the lower / upper grid surface to form a CAE model corresponding to the geological body model; Repeat steps 5.2-5.3 until the corresponding CAE models of all non-lens formation geological models are established; Step 5.4: Select the geological body model of lens strata, obtain the corresponding lens set, and form a closed body in the CAE platform according to the new connection relationship, which is the CAE model corresponding to the geological body model; repeat this step to establish the CAE models of all lens strata; Step 5.5: In the CAE platform, the CAE model of the lenticular formation is subtracted from the CAE model of the non-lenticular formation through Boolean operation; the CAE model after the Boolean operation and the CAE model of the lenticular formation together constitute the CAE model of the three-dimensional geological model.

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