Three-dimensional geological block attribute assignment method based on ray projection and pixel analysis

Abstract

The invention discloses a three-dimensional geological block attribute assignment method based on ray projection and pixel analysis, and belongs to the technical field of geological modeling. The method comprises the following steps: acquiring a triangular net surface model of a geologic horizon; dividing grids on a horizontal plane to form vertical strip-shaped columns; rays are vertically and downwards emitted from the center of the top face of the strip column and intersect with the triangulation network of each layer, and the depth of the top plate and the bottom plate is accurately obtained; vertically and continuously dividing the strip column into centimeter-level resolution pixel units, and marking pixels as 1 or 0 according to a depth interval; and finally, the columns are divided into three-dimensional blocks according to the meter-scale target scale, the sum of pixel marks in each block is counted to serve as the attribute value of the block, and the value directly represents the horizon equivalent thickness or proportion. According to the method, high-precision geometric interface information is subjected to pixelated discrete representation and losslessly aggregated to an engineering scale model, so that the problem that precision and efficiency are difficult to consider in thin-layer, multi-layer and complex structure modeling by a traditional interpolation method is fundamentally solved.

Description

Technical Field

[0001] This invention belongs to the field of three-dimensional geological modeling technology, and specifically relates to a method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis. Background Technology

[0002] In the field of coal resource development, particularly in coal exploration and development, constructing accurate three-dimensional geological models is crucial for resource reserve assessment, mine design, and safe production. Currently, mainstream three-dimensional geological modeling technologies primarily rely on interpolation algorithms based on borehole data and geological interpretation, such as inverse distance weighted (IDW), Kriging, and various deterministic modeling methods.

[0003] However, when faced with geological conditions containing multiple thin coal seams, small spacing between coal seams, and complex structures, the limitations of these traditional methods are fully exposed, and they are difficult to achieve the expected accuracy and efficiency in engineering applications.

[0004] Specifically, the existing technology has the following prominent drawbacks: 1. Insufficient modeling accuracy for thin coal seams: The vertical scale of thin coal seams is much smaller than that of conventional geological blocks. Traditional interpolation algorithms directly interpolate sparse borehole data onto larger blocks (e.g., 12m × 12m × 12m), which leads to severe "smoothing" or "diluting" of the spatial information of thin coal seams, or even complete loss. The interpolation process cannot accurately capture and reproduce the true thickness and lateral distribution of thin coal seams, resulting in model distortion.

[0005] 2. The trade-off between efficiency and accuracy when dealing with multiple coal seams: To improve the ability to distinguish multiple thin coal seams, the most direct method is to reduce the block size. However, this leads to an exponential increase in the number of model elements, greatly increasing the computational burden, reducing modeling efficiency, and even making the model unusable for storage and computation on conventional hardware. Conversely, if the block size is kept large, it is impossible to distinguish adjacent thin coal seams, resulting in the model's accuracy failing to meet requirements. This sharp contradiction between "accuracy" and "efficiency" is particularly prominent in the modeling of multiple thin coal seams.

[0006] 3. Vague Boundary Delineation: Traditional methods rely on interpolation results rather than precise geometric calculations to define the top and bottom surfaces of coal seams. In areas with insufficient borehole control, coal seam boundaries are often unclear, relying on subjective inferences and failing to accurately reflect the complex spatial relationships such as coal seam pinch-outs and bifurcations caused by geological structures like faults and folds.

[0007] 4. Limitations of existing refinement methods: Although some studies have attempted to use more refined voxels (such as 1 meter square) for modeling, the amount of data and computational cost are still high if full-scale refinement modeling is to be carried out over a large area. Moreover, the precise geometric information of geological interfaces has not been effectively utilized as constraints, and the method itself has a bottleneck in principle.

[0008] Therefore, there is an urgent need in this field for an innovative modeling method that can fully utilize high-precision geological interface models to achieve high-precision and high-efficiency characterization of the spatial distribution of multiple thin coal seams without significantly increasing the computational complexity of the final model, thereby fundamentally solving the dilemma of balancing accuracy and efficiency in existing technologies. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis.

[0010] The technical solution adopted in this invention is: a method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis, the key technical points of which include the following steps: Step 1: Obtain the triangular mesh model of the top and bottom plates of multiple geological strata within the area to be modeled; Step 2: Divide the area to be modeled into a grid on the horizontal plane to form multiple vertically extending bar columns; Step 3: For each of the strip columns, emit a ray vertically downward from the center point of its top surface. By calculating the intersection of the ray with each of the triangular mesh models, determine the top and bottom depths of the geological strata at the location of the strip column. Step 4: Divide each of the strip columns vertically into continuous pixel units with centimeter-level resolution; based on the depth information of each geological stratum determined in Step 3, set the identifier value of the pixel unit located between the top and bottom surfaces of each geological stratum to a first value, and set the identifier value of the remaining pixel units to a second value. Step 5: Divide each strip column vertically into multiple three-dimensional geological blocks at the target block scale of meters; for each three-dimensional geological block, calculate the sum of the identification values ​​of all pixel units inside it, and use this sum as the attribute value characterizing the relative content of the target geological layer in the block. Step 6: Output a three-dimensional geological block model containing the attribute values.

[0011] In the above scheme, the grid division on the horizontal plane described in step S2 is performed by using a uniform rectangular grid.

[0012] In the above scheme, the characteristic is that the size of the uniform rectangular grid is consistent with the size of the target block on the horizontal plane in step S5.

[0013] In the above scheme, step S3, calculating the intersection points of the ray with each of the triangular mesh models, includes: calculating the intersection points of the ray with the top triangular mesh model and the bottom triangular mesh model of each geological layer, respectively, to obtain the top surface depth and bottom surface depth of each geological layer.

[0014] In the above scheme, for each geological stratum, the depth of the intersection of the triangular mesh model of its top plate is taken as the top surface depth, and the depth of the intersection of the triangular mesh model of its bottom plate is taken as the bottom surface depth, wherein the top surface depth is less than the bottom surface depth.

[0015] In the above scheme, in step S4, dividing each strip column into multiple high-resolution pixel units along the vertical direction means dividing the entire vertical range of the strip column into continuous pixel units without gaps; the determination condition for the pixel unit located between the top and bottom surfaces of each geological stratum is that the vertical coordinate range of the pixel unit intersects with the interval determined by the depth of the top and bottom surfaces.

[0016] In the above scheme, step S5, which involves calculating the identifier value of all pixel units within it, specifically involves calculating the arithmetic sum of the identifier values; the attribute value is this arithmetic sum.

[0017] In the above scheme, the attribute value is used to characterize the cumulative equivalent thickness or volume ratio of the target geological layer in the corresponding three-dimensional geological block.

[0018] The beneficial effects of this invention are as follows: This method for assigning attributes to three-dimensional geological blocks based on ray casting and pixel analysis, through the organic combination of ray casting and pixel analysis, significantly improves the accuracy and adaptability of geological modeling while maintaining computational efficiency. It demonstrates a clear technical advantage, particularly in scenarios where traditional methods struggle to handle multi-layered thin coal seams and complex geological structures. Its technical effectiveness is not only reflected in the quantitative improvement in modeling accuracy but also in the qualitative breakthrough in methodology, providing a new technical paradigm for the field of geological modeling. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis in an embodiment of the present invention; Figure 2This is a schematic diagram of coal seam modeling based on ray projection in an embodiment of the present invention; Figure 3 This is a schematic diagram of the pixelated representation of bars in an embodiment of the present invention; Figure 4 This is a schematic diagram of 3D block estimation in an embodiment of the present invention. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the following description is provided in conjunction with the accompanying drawings. Figures 1-4 The present invention will be further described in detail below with reference to specific embodiments.

[0022] This embodiment provides a method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis. S101, Establish triangular mesh models of the roof and floor of multiple coal seams.

[0023] This embodiment takes a coal mining area as an example, obtaining the roof and floor triangular mesh models of all coal seams within the mining area to be modeled. These triangular mesh models can be meshed using geological solution planes to form multiple vertical strip columns. They are constructed from interpretation, seismic data, or dense borehole data, resulting in continuous, high-precision curved surface models, such as... Figure 2 As shown, the spatial distribution relationship of multiple coal seams is illustrated.

[0024] S102, Construction of bar columns based on mesh generation: XY in a 3D rectangular region The mining area is divided into XY horizontal planes using a 12m × 12m square grid. Each grid cell extends vertically downwards, traversing the entire vertical depth of the model, thus forming vertical strip columns with a cross-section of 12m × 12m. Figure 1 (Illustration of "bar column division" in Chinese). Each bar column is uniquely identified in space by its planar grid coordinates (i, j).

[0025] S103, Coal seam interface location based on ray projection.

[0026] For each 12m x 12m strip column, a ray is emitted vertically downwards from the center point of its top surface. The coordinates of the center point are calculated as (6m, 6m, Z_max). The calculation method is as follows: Planar coordinates X = i×12 + 6, Y = j×12 + 6, and vertical coordinate Z is the highest point of the modeling area; Using the ray-triangle intersection algorithm in computer graphics, calculate all intersection points of the ray with the roof and floor triangulations of each coal seam (M1, M2, M3…). Sort the intersection points by depth to accurately obtain the roof depth (e.g., Z_M1_top) and floor depth (e.g., Z_M1_bottom) of each coal seam at position (i, j).

[0027] S104: Mark each pixel unit based on the accurate depth data obtained in step S103.

[0028] Each bar is divided into pixel units at 10-centimeter intervals vertically. Based on the positioning result of S102, pixels falling within the coal seam are marked as 1, otherwise marked as 0. Assuming a certain depth range [Z1_top, Z1_bottom] is determined to be a coal seam, all 100 pixels within this range (if the seam thickness is 10 meters) are marked as 1. The remaining pixels are marked as 0.

[0029] Through this step, the originally continuous spatial distribution of coal seams is transformed into a vertical binary 0-1 sequence with a resolution of 10 cm, thereby achieving a refined and discretized characterization of the spatial distribution of coal seams.

[0030] S105, Block assignment based on pixel statistics: Divide the bar column into blocks according to the target scale of 12 meters. The first block corresponds to a depth of 0-12 meters, the second corresponds to 12-24 meters, and so on.

[0031] For each block with a depth of 0-12m, such as the first block, the sum of the identifier values ​​of all the pixel units contained within it is calculated. Since the pixel resolution is 0.1 meters, a 12-meter-high block contains 12 / 0.1 = 120 pixel units. Assuming the sum of the obtained identifier values ​​is N, such as N=85, then the coal seam content attribute value of this 12m×12m×12m three-dimensional block is assigned a value of 85. This value indicates that there are 85 10cm segments of coal within this block, and the equivalent cumulative coal seam thickness is 85 × 0.1m = 8.5m.

[0032] S106, execute repeatedly. Repeat S103-105 for each bar column in the mining area until the assignment of values ​​to the entire 3D model is completed.

[0033] By assembling all the three-dimensional blocks assigned coal seam content attributes, the final three-dimensional geological block model is generated. This model has a 12-meter scale both horizontally and vertically, making it suitable for large-scale resource estimation, mine design, and numerical simulation. Furthermore, its internal attributes accurately reflect the details of coal seam distribution at centimeter-level resolution, such as… Figure 4 As shown, the final block model and its internal attribute distribution are illustrated.

[0034] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for assigning attributes to three-dimensional geological blocks based on ray casting and pixel analysis, characterized in that, Includes the following steps: Step 1: Obtain the triangular mesh model of the top and bottom plates of multiple geological strata within the area to be modeled; Step 2: Divide the area to be modeled into a grid on the horizontal plane to form multiple vertically extending bar columns; Step 3: For each of the strip columns, emit a ray vertically downward from the center point of its top surface. By calculating the intersection of the ray with each of the triangular mesh models, determine the top and bottom depths of the geological strata at the location of the strip column. Step 4: Divide each of the strip columns vertically into continuous pixel units with centimeter-level resolution; Based on the depth information of each geological stratum determined in step 3, the identifier value of the pixel unit located between the top and bottom surfaces of each geological stratum is set to the first value, and the identifier value of the remaining pixel units is set to the second value. Step 5: Divide each strip column vertically into multiple three-dimensional geological blocks at the target block scale of meters; for each three-dimensional geological block, calculate the sum of the identification values ​​of all pixel units inside it, and use this sum as the attribute value characterizing the relative content of the target geological layer in the block. Step 6: Output a three-dimensional geological block model containing the attribute values.

2. The method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis as described in claim 1, characterized in that, The grid division on the horizontal plane described in step 2 is performed using a uniform rectangular grid.

3. The method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis as described in claim 2, characterized in that, The dimensions of the uniform rectangular grid are consistent with the dimensions of the target block on the horizontal plane described in step 5.

4. The method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis as described in claim 1, characterized in that, In step 3, calculating the intersection points of the ray with each of the triangular mesh models includes: calculating the intersection points of the ray with the top triangular mesh model and the bottom triangular mesh model of each geological stratum, respectively, to obtain the top surface depth and bottom surface depth of each geological stratum.

5. The method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis as described in claim 4, characterized in that, For each geological stratum, the depth of the intersection of the triangular mesh model of its top plate is taken as the top surface depth, and the depth of the intersection of the triangular mesh model of its bottom plate is taken as the bottom surface depth, wherein the top surface depth is less than the bottom surface depth.

6. The method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis according to claim 1, characterized in that, In step 4, dividing each strip column vertically into multiple high-resolution pixel units means dividing the entire vertical range of the strip column into continuous pixel units without gaps; the determination condition for the pixel unit located between the top and bottom surfaces of each geological stratum is that the vertical coordinate range of the pixel unit intersects with the interval determined by the depth of the top and bottom surfaces.

7. The method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis according to claim 1, characterized in that, In step 5, the step of calculating the identifier value of all pixel units within it specifically involves calculating the arithmetic sum of the identifier values; the attribute value is this arithmetic sum.

8. The method for assigning attributes to three-dimensional geological blocks based on ray projection and pixel analysis according to claim 7, characterized in that, The attribute value is used to characterize the cumulative equivalent thickness of the target geological layer in the corresponding three-dimensional geological block.

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