A method for modeling geological stratigraphic planes with spatial curvature constraints

Abstract

A spatial curvature-constrained geological strata surface modeling method is disclosed, relating to the field of geological reservoir characterization. The method includes the following steps: identifying missing interpolation points on a structural stratum element; dividing the scattered points into several groups based on azimuth; drawing lines from the interpolation points to the interpolation radius to form azimuth lines; calculating the tangential curvature in the neighborhood and the normal curvature in the neighborhood of existing scattered points; calculating the average tangential curvature of the interpolation points on the azimuth lines of all azimuth groups, and truncating the weighted radii on the azimuth groups; using a linear trend extrapolation prediction method to derive the Z-value for the interpolation points; calculating the Z-value of the interpolation points; and establishing a continuous strata surface by combining the existing points and interpolation points on the strata element. By comprehensively considering structural deformation in different spatial directions, the spatial curvature-constrained geological strata surface modeling method ensures that the interpolation results maintain geological characteristics without deviation.

Description

Technical Field

[0001] This application relates to the field of geological reservoir characterization, and more specifically, to a method for modeling geological strata with spatial curvature constraints. Background Technology

[0002] In seismic interpretation, the spatial distribution of interpretation points is often non-uniform due to factors such as seismic data quality, observation systems, and interpretation methods. During geological modeling, it is necessary to interpolate these interpretation points to achieve a uniform distribution and establish a spatially continuous stratigraphic plane. Common methods include inverse distance weighting, kriging, minimum curvature, and sequential Gaussian. The inverse distance weighting method assumes a simple spatial structure. Kriging interpolation utilizes regional similarity coefficient constraints, requiring a certain degree of structural stability and a relatively uniform spatial distribution of scattered points. The minimum curvature method minimizes the curvature sum in a local area, aiming for maximum smoothness. Sequential Gaussian simulation requires data values ​​to follow a normal distribution. However, in practice, seismic interpretation often occurs in complex tectonic zones with dramatic fluctuations, resulting in low signal-to-noise ratios and difficulties in stratigraphic picking, leading to missing input data during interpolation. These complex tectonic zones are unsuitable for the assumptions of the aforementioned interpolation methods, and the interpolation results can easily lead to deviations in geological phenomena. Summary of the Invention

[0003] The purpose of this application is to provide a geological stratum plane modeling method with spatial curvature constraints, which, by comprehensively considering tectonic deformation in different spatial directions, enables the interpolation results of geological stratum plane modeling to maintain geological characteristics without producing deviations.

[0004] This application is implemented as follows:

[0005] This application provides a method for modeling geological strata with spatial curvature constraints, comprising the following steps:

[0006] S1. Input the spatial point set; set the size of the surface element of the construction layer, perform spatial point position regularization, and determine whether a point on a certain surface element of the construction layer is missing. If it is missing, the point is called the interpolation point and steps S2-S8 are executed; if it is not missing, steps S9 are executed.

[0007] S2. Plane azimuth angle grouping: For a certain interpolation point, calculate the plane azimuth distribution angle of the existing scattered points in the plane relative to the origin of the interpolation point within a given interpolation radius, calculate the maximum curvature in the neighborhood of the existing scattered points in the plane, obtain the average curvature, and divide the scattered points into several groups according to the azimuth angle.

[0008] S3. Establish the azimuth line; Draw a line from the point to be interpolated until it ends at the interpolation radius to form the azimuth line;

[0009] S4. Projection of points on the azimuth line; take a plane that passes through the point to be interpolated and is parallel to the Z direction as the tangential plane, and take a plane that is parallel to the Z direction and perpendicular to the tangential plane as the normal plane; project the nearest existing scattered points onto the azimuth line, and calculate the tangential curvature in the neighborhood, and calculate the normal curvature in the neighborhood of the existing scattered points.

[0010] S5. Weighted radius truncation on azimuth groups: Calculate the tangential curvature of the interpolation points on the azimuth lines of all azimuth groups, and obtain the average value of the tangential curvature. Set a threshold and truncate the weighted radius on the azimuth groups so that the weighted radius of interpolation on different plane azimuth groups is different.

[0011] S6. Interpolation on azimuth groups; For a point to be interpolated, on one of the azimuth groups, based on the projection of the point on the azimuth line, the Z value of the interpolation point is derived by using the linear trend extrapolation prediction method.

[0012] S7. Weighted coefficient processing: Sum the curvature of the projected points on the azimuth group within the cutoff radius to obtain A; Set a parameter B, take B raised to the power of A as the curvature weight coefficient of the azimuth group, sum the curvature weight coefficients of each group, and normalize them to a total of 1.0.

[0013] S8. Calculate the interpolation value; Multiply the back-dated Z value of each azimuth group by the normalized weight coefficient, and sum them up to obtain the Z value of the point to be interpolated.

[0014] S9. Establish a structural strata surface; combine the existing points and interpolation points on the strata surface element into a point set to establish a continuous strata surface.

[0015] In some alternative implementations, spatial curvature is used to constrain the interpolation radius and weighting values.

[0016] In some alternative implementations, spatial weighting values ​​are distinguished on the plane azimuth.

[0017] In some alternative implementations, in step S2, the greater the average curvature, the more azimuth groups there are.

[0018] In some alternative implementations, in step S3, when drawing a line along the azimuth median from the point to be interpolated, spatial points are evenly spaced at intervals equal to the layer element size.

[0019] In some alternative implementations, in step S4, a threshold is set to limit the maximum normal projection radius.

[0020] In some alternative implementations, the parameter B is a real number less than or equal to -1.0.

[0021] In some alternative implementations, the line is drawn from the median azimuth angle grouped by azimuth angles when drawing the line from the point to be interpolated.

[0022] The beneficial effects of this application are as follows: The spatial curvature-constrained geological stratum modeling method provided by this application includes the following steps: inputting a spatial point set to determine whether a point on a certain surface element of a structural stratum is missing, thereby determining the missing interpolation point; determining the planar azimuth distribution angle of the scattered points within a given interpolation radius, calculating the average curvature of the maximum curvature in the neighborhood of the existing scattered points in the plane, and dividing the scattered points into several groups according to the azimuth angle; drawing a line from the point to be interpolated until it ends at the interpolation radius to form an azimuth line; taking a plane passing through the point to be interpolated and parallel to the Z direction as the tangential plane, and taking a plane parallel to the Z direction and perpendicular to the tangential plane as the normal plane, projecting the nearest existing scattered points onto the azimuth line, and calculating the tangential curvature in the neighborhood, calculating the normal curvature in the neighborhood of the existing scattered points; calculating all azimuth angle groups. The tangential curvature of the point to be interpolated on the azimuth line is calculated, and the average tangential curvature is obtained. A threshold is set to truncate the weight radius on the azimuth angle group, so that the weight radius of interpolation on different plane azimuth angle groups is different. For a certain point to be interpolated, the Z value of the interpolated point is back-derived based on the projection of the point on the azimuth line in one of the azimuth groups using the linear trend extrapolation prediction method. The curvature of the projected points on the azimuth group within the truncation radius is summed to obtain A. A parameter B is set, and the curvature weight coefficient of the azimuth group is taken as the base of A raised to the power of B. The curvature weight coefficients of each group of azimuth curvature are summed and normalized to a total of 1.0. The back-derived Z value of each group of azimuth groups is multiplied by the normalized weight coefficient, and the summation is obtained to obtain the Z value of the point to be interpolated. The existing points and interpolated points on the stratigraphic surface element are combined into a point set to establish a continuous stratigraphic surface. The spatial curvature-constrained geological strata modeling method provided in this application, by comprehensively considering tectonic deformation in different spatial directions, enables the interpolation results of geological strata modeling to maintain geological characteristics without producing deviations. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A flowchart illustrating the method for modeling geological strata with spatial curvature constraints provided in this application embodiment;

[0025] Figure 2 This is the input spatial point set map in the geological stratum plane modeling method with spatial curvature constraints provided in the embodiments of this application;

[0026] Figure 3 The planar azimuth near-point projection map in the geological stratum plane modeling method with spatial curvature constraints provided in the embodiments of this application;

[0027] Figure 4 Interpolation point set and structural strata plane effect diagram in the spatial curvature constraint geological strata plane modeling method provided in the embodiments of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0029] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0030] The features and performance of the spatial curvature-constrained geological stratum plane modeling method of this application are further described in detail below with reference to embodiments.

[0031] Please refer to Figure 1 (Refer to) Figures 2 to 4 As shown in the figure, this application provides a method for modeling geological strata with spatial curvature constraints, the specific steps of which are as follows:

[0032] S1, the input spatial point set, which includes:

[0033] S11. Select geological space; Scattered points already exist in the geological space, distributed in an XYZ rectangular coordinate system. The distribution length in the X direction is 3680 meters, and the distribution length in the Y direction is 3280 meters. (Example...) Figure 2 As shown.

[0034] S12, Parameter Settings; Set the interpolation radius to 2000 meters and the curvature weight coefficient parameter B to -1.0.

[0035] S13. Establish the construction layer plane and regularize the spatial point positions. Extract the minimum X and maximum X, minimum Y and maximum Y of existing points, and define a rectangular planar range accordingly. Set the planar dimensions of the layer plane element to 40 meters × 40 meters. Within the rectangle, divide the plane into a finite number of plane elements. Number the plane elements as (i, j), where i and j are integers. Starting from the plane element containing the minimum X and minimum Y, first assign it the number (0, 0), keeping Y constant, and sequentially assign it (0, 1), (0, 2), etc., along the direction of increasing X. After reaching the maximum X, increase Y by 40 meters. Similarly, assign the plane element number at the minimum X to (1, 0), and sequentially assign it (1, 1), (1, 2), etc., along the direction of increasing X. Continue this rule until the maximum X and maximum Y are reached, at which point the numbering ends.

[0036] S14. Determine whether a point on a certain surface element of the layer is missing. If it is missing, the point is called the interpolation point and steps S2-S8 are executed. If it is not missing, step S9 is executed.

[0037] S2, Planar Azimuth Grouping. Taking element number (47, 52) as an example. The element center is located at... Figure 3 The blue square is the point in the middle. Given an interpolation radius of 2000 meters, within this range, calculate the azimuth of existing scattered points on the plane relative to the origin of the point to be interpolated, with a distribution value of 0°-360°. Calculate the maximum curvature in the neighborhood of the existing scattered points on the plane, obtain the average curvature, and divide the scattered points into 16 groups according to their azimuth angles.

[0038] S3. Establish azimuth lines. Starting from the element number point (47, 52), evenly set spatial points at intervals of the layer element size, ending at the interpolation radius.

[0039] S4. Point Projection on the Azimuth Line. A plane passing through the point to be interpolated and parallel to the Z-direction is used as the tangential plane, and a plane parallel to the Z-direction and perpendicular to the tangential plane is used as the normal plane. For a point on the azimuth line, the nearest existing scattered point is projected onto it, and the tangential curvature within the neighborhood is calculated. Since the scattered points are spatially distributed and undulate on the normal plane, projection will produce discrepancies and biases. Therefore, the normal curvature within the neighborhood of the existing scattered points is calculated, and a threshold is set to limit the maximum normal projection radius.

[0040] S5. Weighted radius truncation on azimuth groups. Calculate the tangential curvature on all azimuth groups and obtain the average tangential curvature. This average tangential curvature represents the tangential deformation intensity within the interpolation radius range. Based on this, a threshold is set to truncate the weighted radius on the azimuth groups, meaning that the interpolation weighted radius is different on different plane azimuth groups.

[0041] S6. Interpolation on azimuth groups. On one of the azimuth groups, based on the projection of points on the azimuth line, the Z value of the interpolation point is derived using the linear trend extrapolation prediction method.

[0042] S7. Weighting Coefficient Processing. The greater the tangential deformation, the greater the difference in geological structural characteristics between the point and the interpolation point. The curvature of the projected points within the azimuth group within the cutoff radius is summed (A). The curvature weight coefficient parameter B is set to -1.0. The curvature weight coefficient of this azimuth group is the power of B with A as its base. The curvature weight coefficients of each group are summed and normalized to a total sum of 1.0.

[0043] S8. Obtain the interpolation value. Multiply the back-dated Z value of each azimuth by the normalized weight coefficient, and sum them up to obtain the Z value of the point to be interpolated.

[0044] S9. Establish a structural horizon. Construct a continuous horizon by combining existing points and interpolated points on the horizon element into a point set, such as... Figure 4 As shown by the center dot.

[0045] The spatial curvature-constrained geological stratum modeling method provided in this application determines whether a point on a certain surface element of a structural stratum is missing after inputting a spatial point set, thereby identifying the missing interpolation point. Then, it determines the planar azimuth distribution angle of the scattered points within a given interpolation radius, calculates the average curvature of the maximum curvature in the neighborhood of the existing scattered points, divides the scattered points into several groups according to their azimuth angles, and then draws a line from the point to be interpolated until it ends at the interpolation radius to form an azimuth line. A plane passing through the point to be interpolated and parallel to the Z-direction is taken as the tangential plane, and a plane parallel to the Z-direction and perpendicular to the tangential plane is taken as the normal plane. The nearest existing scattered point is projected onto the azimuth line, and the tangential curvature and normal curvature in the neighborhood of the existing scattered points are calculated. The azimuth lines of all azimuth angle groups are calculated. The tangential curvature of the point to be interpolated is calculated, and the average tangential curvature is obtained. A threshold is set to truncate the weight radius on the azimuth group, so that the weight radius of interpolation on different plane azimuth groups is different. For a certain point to be interpolated, the Z value of the interpolated point is derived from the projection of the point on the azimuth line in one of the azimuth groups using the linear trend extrapolation prediction method. The curvature of the projected points on the azimuth group within the truncation radius is summed to obtain A. A parameter B is set, and the curvature weight coefficient of the azimuth group is taken as the base of A raised to the power of B. The curvature weight coefficients of each group of azimuth curvature are summed and normalized to a total of 1.0. The derived Z value of each group of azimuth groups is multiplied by the normalized weight coefficient, and the summation is used to obtain the Z value of the point to be interpolated. The existing points and interpolated points on the stratigraphic element are combined into a point set to establish a continuous stratigraphic surface. The spatial curvature-constrained geological strata modeling method provided in this application, by comprehensively considering tectonic deformation in different spatial directions, enables the interpolation results of geological strata modeling to maintain geological characteristics without producing deviations.

[0046] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for modeling geological strata with spatial curvature constraints, characterized in that, Includes the following steps: S1, Input spatial point set; Set the size of the surface element of the construction layer, perform spatial point position regularization, and determine whether a point on a certain surface element of the construction layer is missing. If it is missing, the point is called the interpolation point and steps S2-S8 are executed; if it is not missing, step S9 is executed. S2. Plane azimuth angle grouping: For a certain interpolation point, calculate the plane azimuth distribution angle of the existing scattered points in the plane relative to the origin of the interpolation point within a given interpolation radius, calculate the maximum curvature in the neighborhood of the existing scattered points in the plane, obtain the average curvature, and divide the scattered points into several groups according to the azimuth angle. S3. Establish the azimuth line; Draw a line from the point to be interpolated until it ends at the interpolation radius to form an azimuth line; S4. Projection of points on the azimuth line; take a plane that passes through the point to be interpolated and is parallel to the Z direction as the tangential plane, and take a plane that is parallel to the Z direction and perpendicular to the tangential plane as the normal plane; project the nearest existing scattered points onto the azimuth line, and calculate the tangential curvature in the neighborhood, and calculate the normal curvature in the neighborhood of the existing scattered points. S5. Weighted radius truncation on azimuth groups: Calculate the tangential curvature of the interpolation points on the azimuth lines of all azimuth groups, and obtain the average value of the tangential curvature. Set a threshold and truncate the weighted radius on the azimuth groups so that the weighted radius of interpolation on different plane azimuth groups is different. S6. Interpolation on azimuth groups; For a point to be interpolated, on one of the azimuth groups, based on the point projection on the azimuth line, the Z value of the interpolation point is derived by using the linear trend extrapolation prediction method. S7. Weighting coefficient processing: Sum the curvatures of the projected points on the azimuth group within the cutoff radius to obtain A; Set a parameter B, and take the curvature weighting coefficient of the azimuth angle group as the power of B with A as the base. Sum the azimuth curvature weighting coefficients of each group and normalize them to a total of 1.

0. S8. Calculate the interpolation value; multiply the back-dated Z value of each azimuth angle group by the normalized weighting coefficient, and sum them up to obtain the Z value of the point to be interpolated. S9. Establish a structural strata surface; combine the existing points and interpolation points on the strata surface element into a point set to establish a continuous strata surface.

2. The method for modeling geological strata with spatial curvature constraints according to claim 1, characterized in that, The interpolation radius and weighting value are constrained by the spatial curvature.

3. The method for modeling geological strata with spatial curvature constraints according to claim 1, characterized in that, Spatial weighting values ​​are distinguished on the plane azimuth.

4. The method for modeling geological strata with spatial curvature constraints according to claim 1, characterized in that, In step S2, the larger the average curvature, the more azimuth angle groups there are.

5. The method for modeling geological strata with spatial curvature constraints according to claim 1, characterized in that, In step S3, when drawing a line along the azimuth median starting from the point to be interpolated, spatial points are evenly set at intervals based on the layer element size.

6. The method for modeling geological strata with spatial curvature constraints according to claim 1, characterized in that, In step S4, a threshold is set to limit the maximum normal projection radius.

7. The method for modeling geological strata with spatial curvature constraints according to claim 1, characterized in that, The parameter B is a real number less than or equal to -1.

0.

8. The method for modeling geological strata with spatial curvature constraints according to claim 1, characterized in that, When drawing lines, start from the median of the azimuth angle grouped by the azimuth angles when drawing lines from the point to be interpolated.

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