Fault plane curvature calculation method and system based on Off format three-dimensional fault plane model

Abstract

The invention discloses a fault plane curvature calculation method and system based on an Off-format three-dimensional fault plane model, and the method comprises the steps: carrying out the batch reading of the Off-format three-dimensional fault plane model, and obtaining a plurality of fields; step 2, searching in the plurality of fields obtained in the step 1 by adopting a recursive search method to obtain a discrete point set U5, adopting a high-precision three-dimensional fault plane model as a data source, fitting a local quadric surface based on a least square method when calculating the curvature of a certain point of the fault plane on the basis of the constructed Off format three-dimensional fault plane model, and performing approximation to obtain a discrete point set U5; therefore, the curvature of the fault surface is calculated based on a space curvature calculation method, a bending degree index is provided for quantitative evaluation of the fault, the defects that previous quantitative evaluation of the complexity of the stratigraphic structure stays at two dimensions and only spatial distribution conditions are considered are overcome, an important basis is provided for quantitative evaluation work of the complexity of the geological structure, and the method is suitable for popularization and application. The technical problem that the complexity of the current three-dimensional geological structure cannot be quantitatively analyzed in the prior art is solved.

Description

Technical Field

[0001] The invention belongs to the application field of three-dimensional geological models of coal mines, and relates to a fault plane curvature calculation method, in particular to a fault plane curvature calculation method and system based on an Off format three-dimensional fault plane model. Background Art

[0002] When analyzing the structural complexity of a well field, faults are one of the biggest influencing factors among all structural types. However, the current evaluation of geological structural complexity is mostly still based on qualitative analysis. Although some scholars have proposed relevant quantitative evaluation methods, there is still a lack of objectivity in the evaluation indicators, especially when evaluating faults, there is a lack of analysis of the curvature of the fault plane. In addition, the current structural complexity evaluation results only have two-dimensional regional divisions, and lack quantitative evaluation methods in three-dimensional space, which greatly reduces the availability of the evaluation results. At the same time, with the continuous development of current three-dimensional geological modeling, making full use of various drilling and geophysical data to construct three-dimensional geological models provides a reliable model basis for the quantitative evaluation of structural complexity. Therefore, how to make full use of high-precision fault plane models to calculate the curvature of the fault plane, so as to express the curvature of the fault plane and provide objective indicators for the quantitative evaluation of faults, is one of the problems that need to be solved in the quantitative evaluation of geological structural complexity. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method and system for calculating the curvature of a fault plane based on an Off format three-dimensional fault plane model, so as to solve the technical problem that the prior art cannot quantitatively analyze the complexity of the current three-dimensional geological structure.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0005] A method for calculating the curvature of a fault plane of a three-dimensional fault plane model based on an Off format comprises the following steps:

[0006] Step 1, batch read the 3D fault plane model in Off format to obtain multiple fields;

[0007] Each field contains the coordinates of a discrete point (x i ,y i , z i ) and the index data corresponding to the discrete point; the index data is the serial number Id of the discrete point adjacent to the discrete point in each field n ;

[0008] Id n Indicates the sequence number of the nth discrete point adjacent to the discrete point;

[0009] Step 2: Use a recursive search method to search the multiple fields obtained in step 1 to obtain a discrete point set U5, specifically:

[0010] Step 2.1, selecting a discrete point from the discrete points obtained in step 1 as the discrete point to be determined, and reading the corresponding index data;

[0011] Step 2.2, according to the index data, obtain the discrete points adjacent to the discrete point to be found, and form a discrete point set U1;

[0012] Step 2.3, read the index data corresponding to the discrete points in the discrete point set U1, and obtain the discrete points adjacent to each discrete point in the discrete point set U1 according to the index data to form a discrete point set U2;

[0013] Step 2.4, merging the discrete point set U1 and the discrete point set U2 to obtain the discrete point set U3, and using the deduplication algorithm to remove the repeated discrete points in the discrete point set U3 to obtain the discrete point set U4;

[0014] Step 2.5, respectively calculate the distance between each discrete point in the discrete point set U4 and the discrete point to be found, sort the obtained distance values ​​from small to large, and select at least the discrete points corresponding to the first 5 distance values ​​and the discrete point to be found to form a discrete point set U5;

[0015] Step 3, using the least squares principle to fit the discrete points in the discrete point set U5 obtained in step 2, to obtain the local secondary fault surface z;

[0016] z=Ax 2 +By 2 +Cxy+Dx+Ey+F'

[0017] Among them: A, B, C, D, E and F' are all constants;

[0018] Step 4: Calculate the average curvature value K of the discrete point to be determined based on the local secondary fault surface z obtained in step 3 average and the Gaussian curvature value k Gauss , that is, the average curvature and Gaussian curvature of the fault plane are obtained.

[0019] The present invention also includes the following technical features:

[0020] Step three includes the following steps:

[0021] Step 3.1, construct the local secondary fault surface z;

[0022] z=ax 2 +by 2 +cxy+dx+ey+f (1)

[0023] Step 3.2, solve the local quadratic fault surface z constructed in step 3.1 by combining the Lagrange multiplier method to obtain equation group (2);

[0024]

[0025] Among them, x i and i Respectively represent the horizontal and vertical coordinates of the i-th discrete point;

[0026] Step 3.3, convert the equation group (2) obtained in step 3.2 into the matrix form (3), input the discrete points in the discrete point set U5 into the matrix form (3) for solving, and obtain the numerical values ​​A, B, C, D, E and F' of a, b, c, d, e and f respectively, that is, obtain the local secondary fault surface z;

[0027]

[0028] Step 4 specifically includes the following steps:

[0029] Step 4.1, transform the local secondary fault surface z to obtain formula (4), record it as F(x, y, z) = 0, and obtain the expression of the secondary fault surface F(x, y, z), that is, formula (9);

[0030] Ax 2 +By 2 +Cxy+Dx+Ey+F'-z=0 (4)

[0031] F(x, y, z) = Ax 2 +By 2 +Cxy+Dx+Ey+F'-z (9)

[0032] Step 4.2, solve formula (5) according to equation group (6) to obtain solutions λ1 and λ2;

[0033] det H2(λ)=α0+α1λ+α2λ 2 (5)

[0034]

[0035] in:

[0036] det(H1) is the determinant value of matrix H1;

[0037] Hess F is the Hessian matrix of the quadratic fault surface equation F(x, y, z);

[0038] The surface equation F(x, y, z) of the quadratic fault plane is expressed at any discrete point (xi ,y i , z i ) at the gradient matrix;

[0039] Represents the gradient matrix The transpose of

[0040] E is the identity matrix;

[0041] adj H1 represents the adjoint matrix of matrix H1;

[0042] tr represents the trace of the adjoint matrix adj H1 of the matrix H1;

[0043] Step 4.3, substitute the solutions λ1 and λ2 into the following formulas (7) and (8) respectively to obtain the mean curvature value K of the discrete point to be determined: average and the Gaussian curvature value k Gauss , that is, the average curvature and Gaussian curvature of the fault plane are obtained;

[0044]

[0045]

[0046] A fault plane curvature calculation system based on a three-dimensional fault plane model in Off format, and a fault plane curvature calculation method based on the three-dimensional fault plane model in Off format, comprising a data acquisition unit, a model building unit and a curvature calculation unit;

[0047] The data acquisition unit is used to batch read the three-dimensional fault plane model in Off format to obtain multiple fields, each field including the coordinates of the discrete points (x i ,y i , z i ) and the index data corresponding to the discrete point; the index data is the serial number Id of the discrete point adjacent to the discrete point in each field n ; Use a recursive search method to search in the multiple fields obtained in step 1 to obtain a discrete point set U5;

[0048] Id n Indicates the sequence number of the nth discrete point adjacent to the discrete point;

[0049] The model building unit is used to fit the discrete points in the discrete point set U5 using the least squares principle to obtain a local secondary fault plane surface z;

[0050] The curvature calculation unit is used to calculate the average curvature value K of the discrete point to be determined based on the local secondary fault surface z. average and the Gaussian curvature value k Gauss .

[0051] Compared with the prior art, the present invention has the following beneficial technical effects:

[0052] (I) The present invention adopts a high-precision three-dimensional fault surface model as a data source. Based on the constructed Off format three-dimensional fault surface model, when calculating the curvature of a certain point on the fault surface, a local quadratic surface is fitted based on the least squares method and approximated, thereby calculating the curvature of the fault surface based on the spatial curvature calculation method, providing a curvature index for the quantitative evaluation of the fault, overcoming the shortcomings of the previous quantitative evaluation of layer structure complexity that remains in two dimensions and only considers spatial distribution conditions, providing an important basis for the quantitative evaluation of geological structure complexity, and solving the technical problem that the existing technology cannot quantitatively analyze the complexity of the current three-dimensional geological structure.

[0053] (II) In the present invention, according to the characteristics of the Off format, a recursive search method is designed using the index data stored therein, and the optimal discrete points that fit the local secondary fault surface are searched out by calculating the distance between discrete points. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a flow chart of the implementation of the three-dimensional fault plane curvature calculation method of the present invention;

[0055] Figure 2 It is a visualization display diagram of the Off three-dimensional fault plane model of the present invention;

[0056] Figure 3 is a group of discrete points of a fitting surface obtained by associating index data of the present invention;

[0057] Figure 4 It is the fitting effect diagram of the present invention.

[0058] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0059] It should be noted that, unless otherwise specified, all components in the present invention are components known in the art.

[0060] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0061] The present invention provides a method for calculating the curvature of a fault plane of a three-dimensional fault plane model based on the Off format, comprising the following steps:

[0062] Step 1, batch read the 3D fault plane model in Off format to obtain multiple fields;

[0063] Each field contains the coordinates of a discrete point (x i ,y i , z i ) and the index data corresponding to the discrete point; the index data is the serial number Id of the discrete point adjacent to the discrete point in each field n ;

[0064] Id n Indicates the sequence number of the nth discrete point adjacent to the discrete point;

[0065] Step 2: Use a recursive search method to search the multiple fields obtained in step 1 to obtain a discrete point set U5, specifically:

[0066] Step 2.1, selecting a discrete point from the discrete points obtained in step 1 as the discrete point to be determined, and reading the corresponding index data;

[0067] Step 2.2, according to the index data, obtain the discrete points adjacent to the discrete point to be found, and form a discrete point set U1;

[0068] Step 2.3, read the index data corresponding to the discrete points in the discrete point set U1, and obtain the discrete points adjacent to each discrete point in the discrete point set U1 according to the index data to form a discrete point set U2;

[0069] Step 2.4, merging the discrete point set U1 and the discrete point set U2 to obtain the discrete point set U3, and using the deduplication algorithm to remove the repeated discrete points in the discrete point set U3 to obtain the discrete point set U4;

[0070] Step 2.5, respectively calculate the distance between each discrete point in the discrete point set U4 and the discrete point to be found, sort the obtained distance values ​​from small to large, and select at least the discrete points corresponding to the first 5 distance values ​​and the discrete point to be found to form a discrete point set U5;

[0071] Step 3, using the least squares principle to fit the discrete points in the discrete point set U5 obtained in step 2, to obtain the local secondary fault surface z;

[0072] z=Ax 2 +By 2 +Cxy+Dx+Ey+F'

[0073] Among them: A, B, C, D, E and F' are all constants;

[0074] Step 4: Calculate the average curvature value K of the discrete point to be determined based on the local secondary fault surface z obtained in step 3 average and the Gaussian curvature value k Gauss , that is, the average curvature and Gaussian curvature of the fault plane are obtained.

[0075] In the above technical scheme, a high-precision three-dimensional fault surface model is used as the data source. Based on the constructed Off format three-dimensional fault surface model, when calculating the curvature of a certain point on the fault surface, the local quadratic surface is fitted based on the least squares method and approximated. The curvature of the fault surface is calculated based on the spatial curvature calculation method, and its curvature index is provided for the quantitative evaluation of the fault. This overcomes the shortcomings of the previous quantitative evaluation of the complexity of the layer structure that remains in two dimensions and only considers the spatial distribution conditions. It provides an important basis for the quantitative evaluation of the complexity of the geological structure and solves the technical problem that the existing technology cannot quantitatively analyze the complexity of the current three-dimensional geological structure.

[0076] The average curvature can reflect the degree of surface convexity, while the Gaussian curvature focuses on reflecting whether the degree of curvature in different directions of the surface is the same. The calculated curvature value can be used as one of the objective indicators for fusion calculation in the process of fault three-dimensional complexity calculation.

[0077] The three-dimensional fault plane model is an existing construction technology, which has been disclosed in Chinese patent CN202311657207.1 "A three-dimensional construction and analysis method of coal mine fault plane based on LDA and Kriging algorithm". Generally, the fault occurrence data is sorted out by using geological drilling data and three-dimensional seismic exploration data, and then an interpolation algorithm such as the DSI algorithm is used to reconstruct the fault plane in three dimensions.

[0078] In the above technical solution, according to the characteristics of the OFF format, the index data stored therein is used for recursive search, and the optimal discrete points for fitting the local secondary fault surface are searched out by calculating the distance between discrete points.

[0079] Specifically, step three includes the following steps:

[0080] Step 3.1, construct the local secondary fault surface z;

[0081] z=ax 2 +by 2 +cxy+dx+ey+f (1)

[0082] Step 3.2, solve the local quadratic fault surface z constructed in step 3.1 by combining the Lagrange multiplier method to obtain equation group (2);

[0083]

[0084] Among them, x i and i Respectively represent the horizontal and vertical coordinates of the i-th discrete point;

[0085] Step 3.3, convert the equation group (2) obtained in step 3.2 into the matrix form (3), input the discrete points in the discrete point set U5 into the matrix form (3) for solving, and obtain the numerical values ​​A, B, C, D, E and F' of a, b, c, d, e and f respectively, that is, obtain the local secondary fault surface z;

[0086]

[0087] z=Ax 2 +By 2 +Cxy+Dx+Ey+F'.

[0088] Step 4 specifically includes the following steps:

[0089] Step 4.1, transform the local secondary fault surface z to obtain formula (4), record it as F(x, y, z) = 0, and obtain the expression of the secondary fault surface F(x, y, z), that is, formula (9);

[0090] Ax 2 +By 2 +Cxy+Dx+Ey+F'-z=0 (4)

[0091] F(x, y, z) = Ax 2 +By 2 +Cxy+Dx+Ey+F'-z (9)

[0092] Step 4.2, solve formula (5) according to equation group (6) to obtain solutions λ1 and λ2;

[0093] det H2(λ)=α0+α1λ+α2λ 2 (5)

[0094]

[0095] in:

[0096] det(H1) is the determinant value of matrix H1;

[0097] Hess F is the Hessian matrix of the quadratic fault surface equation F(x, y, z);

[0098] The surface equation F(x, y, z) of the quadratic fault plane is expressed at any discrete point (x i ,y i , z i ) at the gradient matrix;

[0099] Represents the gradient matrix The transpose of

[0100] E is the identity matrix;

[0101] adj H1 represents the adjoint matrix of matrix H1;

[0102] tr represents the trace of the adjoint matrix adj H1 of the matrix H1;

[0103] Step 4.3, substitute the solutions λ1 and λ2 into the following formulas (7) and (8) respectively to obtain the mean curvature value K of the discrete point to be determined: average and the Gaussian curvature value k Gauss , that is, the average curvature and Gaussian curvature of the fault plane are obtained;

[0104]

[0105]

[0106] The present invention also provides a fault plane curvature calculation system based on a three-dimensional fault plane model in Off format, and a fault plane curvature calculation method based on a three-dimensional fault plane model in Off format, including a data acquisition unit, a model building unit and a curvature calculation unit;

[0107] The data acquisition unit is used to batch read the 3D fault plane model in Off format to obtain multiple fields, each of which includes the coordinates of discrete points (x i ,y i , z i ) and the index data corresponding to the discrete point; the index data is the serial number Id of the discrete point adjacent to the discrete point in each field n ; Use a recursive search method to search in the multiple fields obtained in step 1 to obtain a discrete point set U5;

[0108] Id n Indicates the sequence number of the nth discrete point adjacent to the discrete point;

[0109] The model building unit is used to fit the discrete points in the discrete point set U5 using the least squares principle to obtain the local secondary fault surface z;

[0110] The curvature calculation unit is used to calculate the average curvature value K of the discrete point to be determined based on the local secondary fault surface z average and the Gaussian curvature value k Gauss .

[0111] Example:

[0112] This embodiment provides a method for calculating the curvature of a three-dimensional fault plane model based on the Off format, such as Figure 1 As shown, the specific steps include:

[0113] Step 1, batch read the 3D fault plane model in Off format to obtain multiple fields;

[0114] Each field contains the coordinates of a discrete point (x i ,y i , z i ) and the index data corresponding to the discrete point; the index data is the serial number Id of the discrete point adjacent to the discrete point in each field n ;

[0115] Generally speaking, the total number of index data is a fixed value in each Off format. Taking the data used in the present invention as an example, the number of discrete points is 189, and each discrete point contains three index data. The specific data is shown in Table 1 below. For example, for a discrete point with an ID of 1, the remaining three points of the surface constructed with it can be confirmed based on its index data, and their IDs are 42, 39, and 13 respectively.

[0116] Table 1faultPlaneOff table

[0117]

[0118]

[0119] Step 2: Determine the remaining discrete points adjacent to the discrete point to be determined based on the corresponding index data of the discrete point to be determined, and confirm the 9 discrete points connected to each other in this way. Then, confirm 8 discrete points based on the distance, and form a set of points for fitting the quadratic surface with the discrete point to be determined.

[0120] Taking the data provided by the present invention as an example, assuming that the ID of the discrete point to be found is 1, looking at Table 1, the three discrete points confirmed by its index data have IDs of 42, 39, and 13, respectively, forming a discrete point set U1, and then according to recursive search, the index discrete points with ID 42 are 1, 24, 15, and 67; the index discrete points with ID 39 are 2, 40, and 1; the index discrete points with ID 13 are 146, 1, 37, and 67, forming a discrete point set U2; the discrete point set U1 and the discrete point set U2 are merged to obtain a discrete point set U3, wherein the discrete point set U3 includes 11 points with IDs of 42, 39, 13, 24, 15, 2, 40, 146, 37, 67, and 67. In the discrete point set U3, the redundant point is the point with ID 67. After removing it, the discrete point set U4 is obtained, including 10 points with IDs 42, 39, 13, 24, 15, 2, 40, 146, 37, and 67. Then, the distance values ​​between these 10 points and the discrete point to be found (the discrete point with ID 1) are calculated respectively, and the first 5 discrete points are sorted from small to large to form the discrete point set U5 with the discrete point to be found with ID 1.

[0121] Step 3, use the least squares method to fit the discrete point set U5 searched by the index in step 2 to solve the surface equation. According to the matrix equation, the equation parameters can be obtained as follows;

[0122]

[0123] The local secondary fault surface z obtained is as follows: Figure 4 .

[0124] z=0.000008713x 2 +0.0003941y 2 -0.0001179xy+0.001723x-0.004924y+543.9

[0125] Step 4: Calculate the average curvature value K of the discrete point to be determined based on the local secondary fault surface z obtained in step 3 average and the Gaussian curvature value k Gauss , that is, the average curvature and Gaussian curvature of the fault plane are obtained.

[0126] ① Calculate the Hessian matrix of the fitted quadratic surface equation F:

[0127]

[0128] ② Calculate the gradient vector of the local discrete point of the curvature value to be calculated Enter the coordinates of the point with Id=1 as follows:

[0129]

[0130] ③HessF obtained from steps ①② and Compose H1 and calculate α0, α1, and α2. The calculation formulas are as follows:

[0131]

[0132] ④Hess F and H2(λ) is formed, and together with α0, α1, α2 obtained in ③, it forms the λ equation. The two solutions λ1 and λ2 of the equation are solved as follows:

[0133]

[0134] Therefore, det H2(λ)=-λ 2 +0.000805626λ+0.0000000001652368

[0135] det H2(λ)=α0+α1λ+α2λ 2It can be transformed into the following equation:

[0136] 0.0006451884392288λ 2 -0.00080550254867λ-1.652367999834763=0 Solving, we get λ1 and λ2 as 0.506167 and -0.484086 respectively.

[0137] ⑤ By λ1, λ2 and Calculate the K of the fault plane average and k Gauss ,as follows:

[0138]

[0139]

[0140]

[0141] k Gauss =k1*k2=-0.244872.

Claims

1. A method for calculating the curvature of a fault plane of a three-dimensional fault plane model based on the Off format, characterized in that: The following steps are involved: Step 1, batch read the 3D fault plane model in Off format to obtain multiple fields; Each field contains the coordinates of a discrete point (x i ,y i , z i ) and the index data corresponding to the discrete point; the index data is the serial number Id of the discrete point adjacent to the discrete point in each field n ; Id n Indicates the sequence number of the nth discrete point adjacent to the discrete point; Step 2: Use a recursive search method to search the multiple fields obtained in step 1 to obtain a discrete point set U5, specifically: Step 2.1, selecting a discrete point from the discrete points obtained in step 1 as the discrete point to be determined, and reading the corresponding index data; Step 2.2, according to the index data, obtain the discrete points adjacent to the discrete point to be found, and form a discrete point set U1; Step 2.3, read the index data corresponding to the discrete points in the discrete point set U1, and obtain the discrete points adjacent to each discrete point in the discrete point set U1 according to the index data to form a discrete point set U2; Step 2.4, merging the discrete point set U1 and the discrete point set U2 to obtain the discrete point set U3, and using the deduplication algorithm to remove the repeated discrete points in the discrete point set U3 to obtain the discrete point set U4; Step 2.5, respectively calculate the distance between each discrete point in the discrete point set U4 and the discrete point to be found, sort the obtained distance values ​​from small to large, and select at least the discrete points corresponding to the first 5 distance values ​​and the discrete point to be found to form a discrete point set U5; Step 3, using the least squares principle to fit the discrete points in the discrete point set U5 obtained in step 2, to obtain the local secondary fault surface z; z=Ax 2 +By 2 +Cxy+Dx+Ey+F’ Among them: A, B, C, D, E and F' are all constants; Step 4: Calculate the average curvature value K of the discrete point to be determined based on the local secondary fault surface z obtained in step 3 average and the Gaussian curvature value k Gauss , that is, the average curvature and Gaussian curvature of the fault plane are obtained.

2. The method for calculating the curvature of a fault plane of a three-dimensional fault plane model based on the Off format as claimed in claim 1, characterized in that: Step three includes the following steps: Step 3.1, construct the local secondary fault surface z; z=ax 2 +by 2 +cxy+dx+ey+f (1) Step 3.2, solve the local quadratic fault surface z constructed in step 3.1 by combining the Lagrange multiplier method to obtain equation group (2); Among them, x i and i Respectively represent the horizontal and vertical coordinates of the i-th discrete point; Step 3.3, convert the equation group (2) obtained in step 3.2 into the matrix form (3), input the discrete points in the discrete point set U5 into the matrix form (3) for solving, and obtain the numerical values ​​A, B, C, D, E and F' of a, b, c, d, e and f respectively, that is, obtain the local secondary fault surface z; z=Ax 2 +By 2 +Cxy+Dx+Ey+F’。 3. The method for calculating the curvature of a fault plane of a three-dimensional fault plane model based on the Off format as claimed in claim 1, characterized in that: Step 4 specifically includes the following steps: Step 4.1, transform the local secondary fault surface z to obtain formula (4), record it as F(x, y, z) = 0, and obtain the expression of the secondary fault surface F(x, y, z), that is, formula (9); Ax 2 +By 2 +Cxy+Dx+Fy+F’-z=0 (4) F(x,y,z)=Ax 2 +By 2 +Cxy+Dx+Ey+F’-z (9) Step 4.2, solve formula (5) according to equation group (6) to obtain solutions λ1 and λ2; det H2(λ)=α0+α1λ+α2λ 2 (5) in: det(H1) is the determinant value of matrix H1; Hess F is the Hessian matrix of the quadratic fault surface equation F(x, y, z); The surface equation F(x, y, z) of the quadratic fault plane is expressed at any discrete point (x i ,y i , z i ) at the gradient matrix; Represents the gradient matrix The transpose of E is the identity matrix; adj H1 represents the adjoint matrix of matrix H1; tr represents the trace of the adjoint matrix adj H1 of the matrix H1; Step 4.3, substitute the solutions λ1 and λ2 into the following formulas (7) and (8) respectively to obtain the mean curvature value K of the discrete point to be determined: average and the Gaussian curvature value k Gauss , that is, the average curvature and Gaussian curvature of the fault plane are obtained; 4. A fault plane curvature calculation system for a three-dimensional fault plane model based on Off format, characterized in that: A method for calculating the curvature of a fault plane based on a three-dimensional fault plane model based on the Off format according to any one of claims 1 to 3, comprising a data acquisition unit, a model building unit and a curvature calculation unit; The data acquisition unit is used to batch read the three-dimensional fault plane model in Off format to obtain multiple fields, each field including the coordinates of the discrete points (x i ,y i , z i ) and the index data corresponding to the discrete point; the index data is the serial number Id of the discrete point adjacent to the discrete point in each field n ; Use a recursive search method to search in the multiple fields obtained in step 1 to obtain a discrete point set U5; Id n Indicates the sequence number of the nth discrete point adjacent to the discrete point; The model building unit is used to fit the discrete points in the discrete point set U5 using the least squares principle to obtain a local secondary fault plane surface z; The curvature calculation unit is used to calculate the average curvature value K of the discrete point to be calculated based on the local secondary fault surface z. average and the Gaussian curvature value k Gauss .

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