A three-dimensional modeling method for a coal mine with complex geology

Abstract

The present application belongs to the technical field of three-dimensional modeling, and specifically discloses a three-dimensional modeling method for a coal mine with complex geology. An array of corner points is generated on the horizontal projection plane of a drilling point, and the roof and floor elevations of each corner point are assigned by interpolation of the roof and floor elevations of the drilling point. A corner point grid framework composed of all the corner points and their elevations serves as an initial three-dimensional geological framework. At the same time, bifurcation conversion points or merging conversion points in the coal seam vertical profile sequence explored by the drilling point are identified as sequence conversion points, and the initial three-dimensional geological framework is divided into partition units according to the sequence conversion points. The sequence conversion points serve as anchor points in each partition unit, and the layered interface radiation gradual change is constructed according to the radiative topological relationship, thereby realizing partition fine modeling. The modeling process is matched with geological changes, and global smoothing distortion caused by mutual interference of different sequence change modes is avoided, so that the real physical boundary of the coal seam in space is accurately restored.

Description

Technical Field

[0001] This invention belongs to the field of 3D modeling technology, and specifically discloses a 3D modeling method for coal mines with complex geology. Background Technology

[0002] Coal mining operations are often located in underground environments. As the depth and intensity of mining continue to increase, the geological conditions faced by coal mines become increasingly complex, with dramatic changes in the sequence of coal seams such as bifurcation and merging. Before coking, in order to ensure safe production, it is necessary to construct a three-dimensional geological model of the coal mine to intuitively and accurately represent the spatial distribution of underground geological bodies.

[0003] Currently, three-dimensional geological modeling of coal mines mainly relies on borehole data and three-dimensional seismic interpretation data, and uses interpolation methods to construct geological interfaces. In existing technologies, such as Chinese patent application with publication number CN121564254A, a method and system for three-dimensional modeling of coal mine geological data and construction of transparent working faces are disclosed. By combining multi-point geostatistics and co-kriging interpolation, multi-source data such as geological boreholes and three-dimensional seismic data are integrated to construct a three-dimensional geological model.

[0004] However, the multi-point geostatistics and co-kriging interpolation methods used in the above schemes are essentially statistical interpolation methods. In reality, coal seam distribution has clear geological origins and physical boundaries, and is not a completely random statistical distribution. Although traditional statistical interpolation methods can reflect large-scale geological trends, when faced with non-stationary geological processes such as coal seam bifurcation and merging, they often treat real geological abrupt changes as gradual artifacts due to over-reliance on statistical smoothing assumptions. This results in models that, while numerically consistent with statistical laws, are severely distorted in terms of geological morphology and cannot accurately reconstruct the true physical boundaries of coal seams in space. Summary of the Invention

[0005] To solve the above-mentioned technical problems, or at least partially solve them, the present invention provides a three-dimensional modeling method for coal mines with complex geology.

[0006] The objective of this invention can be achieved through the following technical solution: a three-dimensional modeling method for coal mines with complex geology, comprising: generating a corner point array on the horizontal projection plane where the borehole point is located, assigning the top and bottom plate elevations of each corner point to the top and bottom plate by interpolating the elevations of the coal seam top and bottom plate at the borehole point, and constructing a corner point grid frame as a three-dimensional geological frame from all corner points and their elevations.

[0007] Based on the vertical profile sequence of coal seams explored by borehole points, bifurcation or merging transition points are identified as sequence transition points and imported into a three-dimensional geological framework.

[0008] The partition boundary lines constructed based on each sequence transition point divide the three-dimensional geological framework into several modeling units.

[0009] Within each modeling unit, the radiative and stable regions are delineated using sequence transition points. Within the radiative region, the radiative direction is determined and the radiative topological relationship is constructed using sequence transition points as topological anchors.

[0010] Layered interface surfaces are constructed using radiation topology within the radiation zone, and stable coal seam interface surfaces are constructed within the stable zone.

[0011] The interface surfaces constructed from the stable zone and the radiation zone are spliced ​​together to form a complete coal seam model.

[0012] The complete coal seam models of each modeling unit are spliced ​​and merged along the partition boundary line to obtain a global three-dimensional geological model of the coal seam.

[0013] Combining all the above technical solutions, the positive effects of this invention are as follows: 1. This invention generates a corner point array on the horizontal projection plane where the borehole point is located, and assigns the top and bottom plate elevations of each corner point to the top and bottom plate by interpolating the elevations of the coal seam top and bottom plate at the borehole point. The corner point grid frame, composed of all corner points and their elevations, serves as a three-dimensional geological framework, providing a unified spatial benchmark and a regular geometric skeleton for subsequent modeling. This ensures that different modeling units have consistent spatial resolution and topological structure under the corner point grid frame, thereby guaranteeing the structural consistency of the global three-dimensional geological model of the coal seam.

[0014] 2. This invention identifies bifurcation or merging transition points by utilizing the vertical profile sequence of coal seams explored from boreholes. These points serve as sequence transition points, which are then used to divide the modeling unit within a three-dimensional geological framework. This allows for the construction of radiative gradients at the layered interface within each modeling unit, using sequence transition points as anchors and based on radiative topological relationships. This enables refined, partitioned modeling, ensuring that the modeling process matches geological changes and avoiding global smoothing distortions caused by interference between different sequence change patterns. Consequently, it accurately reconstructs the true physical boundaries of the coal seam in space. Attached Figure Description

[0015] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0016] Figure 1 This is a diagram illustrating the implementation steps of the method of the present invention;

[0017] Figure 2 This is a flowchart illustrating the implementation of bifurcation transition point identification in this invention.

[0018] Figure 3 This is a flowchart illustrating the implementation of the merged conversion point identification in this invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] See Figure 1 As shown, this invention proposes a three-dimensional modeling method for coal mines with complex geology, including: S1, generating a corner point array on the horizontal projection plane where the borehole point is located, assigning the top and bottom plate elevations of each corner point to the top and bottom plate by interpolating the elevations of the coal seam top and bottom plate of the borehole point, and forming a corner point grid frame as a three-dimensional geological frame by all corner points and their elevations.

[0021] In 3D modeling of coal mines, due to the heterogeneity of the spatial distribution of underground geological bodies and the fact that the modeling process is constrained by geological laws and geometric topological relationships, it is not possible to endlessly perform numerical fitting without considering the actual geological conditions. Therefore, it is necessary to construct a 3D geological framework before modeling, based on real geological information.

[0022] The prerequisite for constructing a three-dimensional geological framework is to determine the framework connection points that support the coal seam structure. The location and properties of the connection points need to be obtained through borehole sampling to obtain structural information such as the elevation of the top and bottom plates of the coal seam and the thickness of the layers. This information is used to constrain the spatial morphology of the framework and ensure that the framework can reflect the actual occurrence state of the coal seam, thus providing a basis for the subsequent construction of the three-dimensional geological model.

[0023] In a specific construction embodiment, S11, the elevation data of the coal seam roof and floor at each borehole location are obtained from the borehole data of coal mine exploration. The elevation data of the coal seam roof and floor reflect the spatial extent of the coal seam in the vertical direction at the borehole location. Each borehole location includes its planar coordinates in a unified mining coordinate system. In one example, the mining coordinate system is an independent plane rectangular coordinate system for the mining area. Specifically, the origin of the coordinate system is usually set at the southwest corner of the mining area. The central meridian of the survey area is used as the vertical axis, with north as positive; the direction perpendicular to the vertical axis is used as the horizontal axis, with east as positive. This is used to uniformly represent the spatial position of all geological data within the mining area.

[0024] S12. The planar coordinates of each borehole point and the corresponding roof elevation data constitute a discrete point set of the coal seam roof, and the planar coordinates of each borehole point and the corresponding floor elevation data constitute a discrete point set of the coal seam floor, reflecting the elevation distribution characteristics of the coal seam roof and floor at the discrete borehole locations.

[0025] S13. Although borehole points can reflect the elevation of the top and bottom of the coal seam at their location, the borehole points are finite and discrete. Borehole points alone cannot serve as the frame connection points covering the entire modeling area. In order to construct a complete three-dimensional geological framework, a regularly distributed corner point array is generated on the horizontal projection plane where the borehole points are located according to the preset X-direction grid spacing and Y-direction grid spacing. The corner point array covers the distribution range of all borehole points.

[0026] The planar coordinates of each corner point are determined by its row and column position in the grid and the preset grid spacing. For example, the planar coordinates of the corner point are: ,in , , , Let be the starting plane coordinates of the corner point array. , represents the grid spacing in the X and Y directions, respectively, and i and j are the row and column numbers of the corner points in the grid. The generated corner points are actually continuous supplements to the drill points, used to fill the spatial gaps between discrete drill points.

[0027] S14. Since the generated corner points only have planar coordinates and lack elevation attributes as frame connection points, it is difficult to determine their specific location in three-dimensional space. Therefore, considering that the generated corner points and borehole points are on the same horizontal projection plane, for each corner point, based on the spatial distance between its planar coordinates and the planar coordinates of each borehole point, select several borehole points that are closest to it, such as 4 or 8 borehole points adjacent to the planar coordinates of the corner point as interpolation nodes. Because the distance is relatively close, there will be no drastic changes in geological structure and coal seam occurrence. The elevation data of these borehole points in the discrete point set of the coal seam roof and the discrete point set of the coal seam floor are used as the interpolation basis. The roof elevation value and floor elevation value at the corner point are calculated by interpolation.

[0028] S15. After the above steps, all corner points have planar coordinates and the elevation of the top and bottom plates of the coal seam. In a three-dimensional rectangular coordinate system, a three-dimensional spatial point can be determined based on the planar coordinates and the elevation of the top and bottom plates of the coal seam. Connecting these points forms a corner point grid frame, which is the three-dimensional geological frame. The area within the frame is the geological space of the coal seam to be modeled, providing a unified gridded base for the subsequent construction of the three-dimensional geological model.

[0029] S2. Identify bifurcation or merging transition points based on the vertical profile sequence of coal seams explored from borehole points, use them as sequence transition points, and import them into a three-dimensional geological framework.

[0030] After constructing the three-dimensional geological framework, coal seam modeling is required within the framework. Because coal seam deposition is influenced by the geographical environment and is not homogeneously distributed, especially in complex geological environments, coal seams often bifurcate due to uneven settlement of the sedimentary basement, and then merge as the sedimentary environment stabilizes. Traditional methods of uniform interpolation modeling within the framework ignore the topological constraints of sequence boundaries and smooth abrupt geological changes at bifurcation and merging points, resulting in geometric anomalies such as stratigraphic penetration and sequence disorder in the generated model.

[0031] To address the aforementioned issues, this invention identifies sequence transition points in coal seams and applies them to a three-dimensional geological framework to guide zonal modeling within that framework, ensuring that the model can capture abrupt changes in the coal seam structure.

[0032] See Figure 2 and Figure 3 As shown, in a preferred embodiment of the present invention, the sequence transition point identification process is as follows: S21. Since sequence transition points reflect the abrupt changes in the internal structure of coal seams, they rely on vertical profile data of coal seams obtained through borehole exploration. In coal mine geological exploration, boreholes can obtain the lithological sequence along the depth direction, i.e., the vertical profile of the coal seams, through core sampling. This profile records the thickness of each stratum, including coal seams and interbedded rock, from the roof to the floor.

[0033] Based on this, the thickness of the main coal seam and the thickness of the interbedded rock layer are extracted from the vertical profile of each borehole point: the main coal seam refers to the main coal layer with good continuity and relatively stable thickness; the interbedded rock layer refers to the non-coal rock layer sandwiched inside the main coal seam. The thickness of the main coal seam is the net thickness of the main coal layer in the vertical direction, and the thickness of the interbedded rock layer is its vertical scale in the coal seam sequence.

[0034] S22. In order to capture the spatial evolution trend of coal seam structure, adjacent boreholes in space are sorted along the working face advance direction to form a borehole analysis path. The thickness values ​​of the main coal seam of adjacent boreholes are compared along this path in turn. The purpose is to identify the abrupt change characteristics of coal seam thickness in space. Such abrupt change is often a precursor to coal seam bifurcation or merging.

[0035] S23. When the thickness of the main coal seam at a certain borehole point decreases relative to the thickness of the main coal seam at the previous adjacent borehole point, and the thickness of the interbedded gangue layer at this borehole point is greater than zero while the thickness of the interbedded gangue layer at the previous adjacent borehole point is zero, it indicates that the original single coal seam begins to split into multiple layers at this location, separated by interbedded gangue. Based on this, the borehole point is marked as a bifurcation transition point, representing the starting position of the coal seam sequence evolution from a single coal seam to multiple branches.

[0036] When the thickness of the main coal seam at a certain borehole point increases relative to the thickness of the main coal seam at the previous adjacent borehole point, and the thickness of the interbedded gangue layer at that borehole point decreases, it indicates that the previously separated coal seams have re-merged into a whole at this point. Based on this, the borehole point is marked as the merging and conversion point, representing the starting position of the convergence of multi-branch coal seams into a single coal seam.

[0037] S24. Sequence transition points are formed by the bifurcation transition points and the merging transition points.

[0038] S3. The partition boundary lines constructed based on each sequence transition point divide the three-dimensional geological framework into several modeling units.

[0039] After identifying sequence transition points (STPs), to achieve refined modeling of complex coal seam structures, the 3D geological framework needs to be rationally partitioned based on these STPs. The implementation process is as follows: Considering that the purpose of partitioning is to adopt matching modeling strategies for coal seam structures in different regions, thereby improving the geological realism of the model, each modeling region should contain only one STP, serving as the sole control center for the coal seam structure in that region. Therefore, each STP is used as a growth point, and expansion is simultaneously and uniformly extended outwards on the horizontal projection plane of the 3D geological framework. When the expansion regions of different growth points first meet, expansion stops, and the line connecting the meeting points serves as the partition boundary line.

[0040] A closed area enclosed by the boundary lines of each partition is a modeling unit, and each modeling unit contains only one sequence transition point.

[0041] S4. Within each modeling unit, use sequence transition points to delineate the radiation zone and the stable zone. Within the radiation zone, use sequence transition points as topological anchor points to determine the radiation direction and construct radiation topology relationships.

[0042] Although each modeling unit is divided based on sequence transition points, reflecting the geological features where local coal seam structures may bifurcate or merge, the coal seams within that unit are not all in a state of structural abrupt change. Since the modeling unit is generated through spatial expansion based on the nearest neighbor principle, its boundary only reflects the control domain and does not imply that all locations within the unit exhibit the same degree of sequence change. In fact, in areas far from the sequence transition point, coal seams often maintain a relatively continuous and stable single-layer morphology; while structural changes are usually concentrated in localized areas near the transition point. Using a uniform modeling strategy for the entire modeling unit would not only result in computational redundancy but may also introduce unnecessary geometric perturbations.

[0043] To this end, the present invention further divides each modeling unit into a radiation zone and a stable zone. This secondary partitioning can capture local geological abrupt changes while preserving the smoothness of a large coal seam.

[0044] The specific implementation process applied to the above steps is as follows: S41, use sequence transition points to delineate the radiation zone and the stable zone.

[0045] A circular area is delineated as the radiation zone with the sequence transition point as the geometric center and the spatial range of the sequence change of the coal seam as the radius. This is because during the bifurcation or merging process, the changes in the coal seam structure usually originate from the transition point and spread radially in a specific direction.

[0046] Specifically: a) When the sequence transition point is a bifurcation transition point, that is, the main coal seam begins to split into multiple layers, the spatial range is taken as the maximum distance from the transition point along the extension direction of each branch to the position where the thickness of the main coal seam no longer decreases and the thickness of the interbedded gangue no longer increases in the adjacent borehole. This position marks the completion of the bifurcation process. If there is no direct data between the boreholes, the position is estimated by interpolation.

[0047] b) When the sequence transition point is a merging transition point, that is, multiple coal seams begin to merge into a single main coal seam, the spatial range is taken as the maximum distance from the transition point along the merging direction to the position where the thickness of the interbedded gangue layer in the adjacent borehole first decreases to zero. This position represents the end of the merging process and the coal seam is restored to a single continuous stratum.

[0048] Furthermore, the area outside the radiation zone is the stable zone, where the coal seam structure no longer changes with spatial location, depending specifically on the type of sequence transition point: when the sequence transition point is a bifurcation transition point, the bifurcation process is completed at the boundary of the radiation zone, and the coal seam in the stable zone maintains a stable three-layer structure, namely the upper layer, the interbedded gangue layer, and the lower layer, with the thickness of each layer equal to the target thickness at the boundary of the radiation zone, and no longer changing.

[0049] When the sequence transition point is a merging transition point, the merging process is completed at the boundary of the radiation zone, and the coal seam in the stable zone is restored to a single main coal seam, and there is no longer a branch structure.

[0050] S42. Determine the radiation direction within the radiation zone to reflect the geometric trend of coal seam sequence evolution. If this direction is not clearly defined, subsequent modeling will lack structural guidance, which may lead to interface distortion or topological distortion. Specifically, within each modeling unit, the radiation direction is determined to be outward radiation from the sequence transition point.

[0051] S43. Due to the bifurcation or merging of coal seams within the radiation zone, multiple interconnected coal seam interfaces need to be constructed during modeling. These interfaces are not spatially independent but have clear geometric dependencies. If traditional interpolation methods are used to model each interface separately, the lack of constraints on the interlayer structural relationships can easily lead to topological errors such as intersections and gaps between adjacent interfaces in the transition region. Therefore, this invention constructs a radial topological relationship within the radiation zone using sequence transition points as topological anchor points, thereby geometrically constraining the structural consistency of each coal seam interface.

[0052] The specific radiation topology is as follows: the coal seam undergoes a sequence change at the sequence transition point, and each stratification interface extends radially from the sequence transition point along a defined radiation direction.

[0053] S5. Construct a layered interface surface in the radiation zone using radiation topology, and construct a stable coal seam interface surface in the stable zone.

[0054] After further dividing the modeling unit into stable and radiating zones, local modeling can be implemented for the geological characteristics of different regions.

[0055] In one feasible implementation, a layered interface surface model is performed within the radiation region based on the aforementioned constructed radiation topology relationship, specifically divided into the following two cases: Case 1, the sequence transition point is a bifurcation transition point.

[0056] Step 1: Determine the type of layer to be constructed within the radiation zone.

[0057] When the sequence transition point is a bifurcation transition point, based on the development characteristics of interbedded rock layers in the borehole vertical profile, the bifurcation region typically exhibits a three-layer structure: upper layer - interbedded rock layer - lower layer. That is, the original main coal seam is divided into two minable layers by interbedded rock layers. Therefore, it is necessary to construct the top and bottom interfaces of each of the three sequence units: upper layer, interbedded rock layer, and lower layer.

[0058] Step 2: Determine the thickness distribution pattern of each layer.

[0059] Constructing a layered interface surface requires defining the top and bottom elevations of each layer at any location in space. These elevations are determined by the layer thickness at that location and the reference elevation. Therefore, the thickness distribution of each layer within the radiation zone must first be determined.

[0060] Since the bifurcation transition point is the starting point of the bifurcation process, the coal seam has not yet truly split at this location, and the thickness of both the upper and lower layers is zero, with no interbedded gangue layers developed. Moving outward along the radial direction, the thickness of each layer starts from zero and increases with the distance from the bifurcation transition point, reaching its target thickness at the boundary of the radial zone.

[0061] Let the radius of the radiation zone be R. For any location at a distance d from the bifurcation transition point, the layer thickness at that point is determined by a linear increase in distance from the bifurcation transition point. ,in The target thickness at the boundary of the radiation zone is defined by the layering.

[0062] In the above formula, It reflects the relative position of any point with respect to the entire radiation area.

[0063] Specifically, when d=0, it is at a bifurcation transition point, and substituting into the formula yields... This indicates that the coal seam has not yet split, and neither the upper nor lower layers have formed, with a thickness of zero.

[0064] When 0 That is, when located within the radiation zone, The linear increase rate is between 0 and... The spaces between them indicate that stratification is gradually developing.

[0065] When d=R, the boundary of the radiation zone is reached. Substituting this into the formula, we get... This indicates that the stratification has fully developed and reached the preset target thickness.

[0066] The target thickness for each layer is determined as follows: Let the total thickness of the coal seam in the stable zone be denoted as... This is the sum of the thicknesses of the upper layer, the interbedded rock layer, and the lower layer. This value can be obtained from the statistics of borehole data in the stable zone. The average thickness ratio of the interbedded rock layer is calculated based on the borehole data in the stable zone. For example, assuming there are n boreholes in the stable zone, for each borehole, the thickness of the interbedded rock layer in that borehole is divided by the total thickness of the coal seam at that borehole to obtain the thickness ratio of the interbedded rock layer in that borehole. Finally, the arithmetic mean of the thickness ratios of the interbedded rock layer in all boreholes is taken as the average thickness ratio.

[0067] After deducting the thickness of the interbedded gangue layer from the total thickness of the coal seam in the stable zone, the remaining thickness is allocated equally between the upper and lower layers based on the following: The target thickness of the upper layer is: .

[0068] The target thickness of the lower layer is: .

[0069] The target thickness of the interlayer is: .

[0070] Step 3: Determine the top and bottom elevations of each layer interface.

[0071] After determining the thickness distribution, it is necessary to further determine the top and bottom elevations of each layer interface. To maintain a continuous transition with the interface corresponding to the stable zone, the coal seam floor interface is used as the reference datum. This is because the coal seam floor is an objectively existing spatial interface, and its position is continuous regardless of whether the coal seam branches.

[0072] The specific elevation allocation method is as follows: Lower layer bottom plate elevation = Coal seam bottom plate elevation.

[0073] The elevation of the lower layer top slab = the elevation of the lower layer bottom slab + the thickness of the lower layer.

[0074] The elevation of the bottom slab of the interbedded coal layer is equal to the elevation of the top slab of the lower layer.

[0075] The elevation of the top plate of the interbedded gangue layer = the elevation of the bottom plate of the interbedded gangue layer + the thickness of the interbedded gangue layer.

[0076] The elevation of the upper layer bottom plate is equal to the elevation of the interlayer top plate.

[0077] The elevation of the top slab of the upper layer = the elevation of the bottom slab of the upper layer + the thickness of the upper layer.

[0078] The elevation of the coal seam floor is obtained by interpolation of the floor elevation of the corner points in the corner grid frame within the radiation zone.

[0079] Step 4: Construct the layered interface surface.

[0080] Based on the above steps, the top and bottom elevations of each layer at each corner point within the radiation zone have been determined. To achieve smooth spatial extension and continuous thickness variation of the interface, a surface fitting method based on spline functions is used for modeling. The specific process is as follows: First, the planar coordinates of each corner point in the corner grid frame within the radiation zone and the top and bottom elevations of their corresponding layers are used as input data.

[0081] Then, under the constraint of the radiation direction, surface fitting is performed on the top and bottom interfaces of each layer. During the surface fitting process, a common boundary constraint is applied: the boundary of the bottom interface of the upper layer coincides with the boundary of the top interface of the intercalary layer at the bifurcation transition point, and the boundary of the bottom interface of the intercalary layer coincides with the boundary of the top interface of the lower layer at the bifurcation transition point.

[0082] Case 2: The sequence transition point is a merge transition point.

[0083] Step 1: Determine the type of layer to be constructed within the radiation zone.

[0084] When the sequence transition point is a merging transition point, the vertical structure typically consists of two independent coal seams: an upper branch layer and a lower branch layer. These two layers gradually converge near the merging transition point and eventually merge into the main coal seam. Therefore, it is necessary to construct the top and bottom interfaces of the upper and lower branch layers separately.

[0085] Step 2: Determine the thickness distribution pattern of each branch layer.

[0086] At the merging and conversion point, multiple branch layers begin to converge into a single coal seam. At this time, the individual branch layers have not yet begun to merge, and their thickness is at its normal thickness. As they gradually converge into the main coal seam along the radial direction, their thickness gradually decreases, eventually decreasing to zero at the boundary of the radial zone.

[0087] Let the radius of the radiation zone be R. For any location at a distance d from the merging transition point, the layer thickness at that point is determined according to a linear decreasing relationship with the distance from the bifurcation transition point. ,in The normal thickness of the branch layer at the merging transition point is determined by the actual thickness of the branch layer in the borehole at or immediately adjacent to the merging transition point. If the borehole at the merging transition point completely exposes the branch layer, the borehole thickness is used directly; otherwise, the arithmetic mean of the thickness of the branch layer in multiple boreholes near the transition point within the radiation zone is taken.

[0088] In the above formula, when d=0, it is at the bifurcation transition point. Substituting this into the formula, we get... This indicates that the coal seam branch at this location has not yet merged, and the branch layer still retains its original thickness.

[0089] When 0 That is, when located within the radiation zone, The linear reduction ratio is between A value between 0 and 0 indicates that the branch layer is gradually becoming thinner.

[0090] When d=R, the boundary of the radiation zone is reached. Substituting this into the formula, we get... This indicates that the branch layer has disappeared here and has been completely incorporated into the main coal seam.

[0091] Step 3: Determine the top and bottom elevations of each branch layer interface.

[0092] After determining the thickness distribution, it is necessary to further determine the top and bottom elevations of each branch layer interface. To maintain a continuous transition with the main coal seam interface in the stable zone, the roof and floor interfaces of the main coal seam in the stable zone are used as reference datum surfaces.

[0093] The specific elevation allocation method is as follows: Lower branch layer bottom elevation = Main coal seam bottom elevation (consistent with the stable zone).

[0094] Elevation of the top plate of the lower branch layer = Elevation of the bottom plate of the lower branch layer + Thickness of the lower branch layer.

[0095] Elevation of the upper branch layer bottom plate = Elevation of the main coal seam top plate - Thickness of the upper branch layer.

[0096] The elevation of the upper branch layer roof is equal to the elevation of the main coal seam roof (consistent with the stable zone).

[0097] When d=R, the thickness is zero, the elevation of the bottom plate of the upper branch layer is equal to the elevation of the top plate of the upper branch layer, and the elevation of the top plate of the lower branch layer is equal to the elevation of the bottom plate of the lower branch layer. That is, the branch layer disappears and completely merges into the main coal seam.

[0098] The elevations of the main coal seam roof and floor are obtained by interpolation of the elevations of the corner points in the corner grid frame within the radiation zone.

[0099] Step 4: Construct the branch layer interface surface.

[0100] Based on the above steps, the top and bottom elevations of each branch layer at each corner point within the radiation zone have been determined. To achieve smooth spatial extension and continuous thickness variation of the interface, a surface fitting method based on spline functions is used for modeling. The specific process is as follows: First, the plane coordinates of the corner points in the corner grid frame within the radiation zone and the top and bottom elevations of their corresponding branch layers are used as input data.

[0101] Then, surface fitting is performed on the top and bottom interfaces of the upper and lower branch layers respectively.

[0102] Topological constraints are applied at the boundary of the radiation zone: the bottom interface of the upper branch layer and the top interface of the lower branch layer coincide with the boundary of the main coal seam interface at the boundary of the radiation zone, realizing the geometric intersection of the three.

[0103] In another feasible implementation, the construction of stable coal seam interface surfaces in the stable zone needs to be carried out according to the type of sequence transition point: (i) When the sequence transition point is a merging transition point, the stable zone is a single main coal seam, whose spatial morphology is jointly defined by the roof interface and the floor interface. In order to avoid the model deviating from the actual stratigraphic morphology, the corner points located in this area in the corner point grid frame are used as geometric constraint points. The reason for introducing geometric constraint points is that these corner points have obtained accurate coal seam roof elevation and floor elevation through previous interpolation, which can carry and transmit real geological information and provide spatial location benchmarks for interface construction.

[0104] The top interface point set is constructed using the planar coordinates of each corner point in the stable zone and its corresponding roof elevation, and the bottom interface point set is constructed using the floor elevation. The two point sets are then triangulated. Triangulation is a calculation method that transforms discrete point sets into continuous curved surfaces. By connecting adjacent points, an irregular triangular network is formed. The final constructed top interface curved surface corresponds to the spatial distribution of the coal seam roof, and the bottom interface curved surface corresponds to the spatial distribution of the coal seam floor. The two together enclose the main coal seam interface in the stable zone.

[0105] (ii) When the sequence transition point is a bifurcation transition point, the stable region consists of a three-layer structure: an upper layer, a gangue layer, and a lower layer. The thickness of each layer remains constant and is equal to the target thickness at the boundary of the radiation region.

[0106] Based on the corner points in the corner point mesh framework within the stable region, the top and bottom interface surfaces of each layer are constructed respectively.

[0107] Then, surface fitting is performed on the top and bottom interfaces of each layer to generate a continuous surface. Each layer interface remains parallel and of equal thickness within the stable region, and its thickness is continuous with the corresponding interface within the radiation region at the boundary of the radiation region.

[0108] S6. The interface surfaces constructed from the stable zone and the radiation zone are spliced ​​together to form a complete coal seam model.

[0109] After completing the local interface modeling in both the stable and radiative zones of the modeling unit, the stable coal seam interface surface constructed in the stable zone and the layered interface surfaces constructed in the radiative zone are spatially spliced ​​together. During splicing, the elevation and thickness of the corresponding interfaces are ensured to be continuous at the boundary of the radiative zone to form a complete three-dimensional coal seam model within the unit.

[0110] S7. The complete coal seam models of each modeling unit are spliced ​​and merged along the partition boundary line to obtain a global 3D geological model of the coal seam. The specific implementation is as follows: Since each modeling unit is generated based on independent seed points, their internal modeling logic may differ. Therefore, boundary splicing and merging are required at the unit boundaries to eliminate interface misalignment caused by local modeling differences. Specifically, the complete coal seam models of adjacent modeling units are aligned along their shared partition boundary line. The corner points of the grid frame on both sides of the partition boundary line are used as common geometric constraints. The purpose is to force adjacent units to share consistent elevation values ​​at the boundary, thereby achieving seamless interface connection. Based on this, the coal seam interface surfaces on both sides of the boundary are smoothed.

[0111] After completing the boundary alignment and transition processing of all adjacent modeling units, the complete coal seam models are merged into a global three-dimensional geological model of the coal seam.

[0112] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0113] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0114] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0115] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0116] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-dimensional modeling method for coal mines with complex geological conditions, characterized in that, Includes the following steps: A corner point array is generated on the horizontal projection plane where the borehole point is located. The elevation of the top and bottom plates of the coal seam at the borehole point is interpolated to assign the top and bottom plate elevations to each corner point. The corner point grid frame is formed by all corner points and their elevations as a three-dimensional geological frame. Based on the vertical profile sequence of coal seams explored by borehole points, bifurcation or merging transition points are identified as sequence transition points and imported into a three-dimensional geological framework. The partition boundary lines constructed based on each sequence transition point divide the three-dimensional geological framework into several modeling units; Within each modeling unit, the radiative region and the stable region are delineated using sequence transition points. Within the radiative region, the radiative direction is determined and the radiative topological relationship is constructed using sequence transition points as topological anchor points. Layered interface surfaces are constructed using radiation topology within the radiation zone, and stable coal seam interface surfaces are constructed within the stable zone. The interface surfaces constructed from the stable zone and the radiation zone are spliced ​​together to form a complete coal seam model; The complete coal seam models of each modeling unit are spliced ​​and merged along the partition boundary line to obtain a global three-dimensional geological model of the coal seam.

2. The method for three-dimensional modeling of coal mines with complex geology as described in claim 1, characterized in that: The three-dimensional geological framework is constructed as follows: The elevation data of the coal seam roof and floor at each borehole point are obtained from the borehole data of coal mine exploration. The location of each borehole point includes its plane coordinates in a unified mining coordinate system. The planar coordinates of each borehole point and the corresponding roof elevation data constitute a discrete point set of the coal seam roof, and the planar coordinates of each borehole point and the corresponding floor elevation data constitute a discrete point set of the coal seam floor. A regularly distributed array of corner points is generated on the horizontal projection plane where the drilling point is located, according to the preset grid spacing in the X direction and the grid spacing in the Y direction; For each corner point, based on the spatial distance between its planar coordinates and the planar coordinates of each borehole point, several borehole points that are closest to it are selected as interpolation nodes. The elevation data of these borehole points in the discrete point set of the coal seam roof and the discrete point set of the coal seam floor are used as the interpolation basis. The roof elevation value and floor elevation value at the corner point are calculated by interpolation. A corner grid framework is formed by all corner points and their corresponding top and bottom elevations. This corner grid framework is the three-dimensional geological framework.

3. The method for three-dimensional modeling of coal mines with complex geology as described in claim 1, characterized in that: The process for identifying the hierarchical transition point is as follows: Extract the thickness values ​​of the main coal seam and the interbedded gangue layer at each borehole point from the vertical profile sequence of the coal seam at each borehole point; The boreholes that are spatially adjacent are sorted along the working face advance direction to form a borehole analysis path. The thickness values ​​of the main coal seam of adjacent boreholes are compared sequentially along this path. When the thickness of the main coal seam at a certain borehole point decreases relative to the thickness of the main coal seam at the previous adjacent borehole point, and the thickness of the interbedded gangue layer at that borehole point is greater than zero while the thickness of the interbedded gangue layer at the previous adjacent borehole point is zero, the location of that borehole point is marked as a bifurcation transition point. When the thickness of the main coal seam at a certain borehole point increases relative to the thickness of the main coal seam at the previous adjacent borehole point, and the thickness of the interbedded gangue layer at that borehole point decreases, the location of that borehole point is marked as a merge conversion point. Sequence transition points are formed by the combination of bifurcation transition points and merging transition points.

4. The method for three-dimensional modeling of coal mines with complex geology as described in claim 1, characterized in that: The process of dividing the three-dimensional geological framework into several modeling units is as follows: Using each sequence transition point as a growth point, it expands uniformly in all directions simultaneously on the horizontal projection plane of the three-dimensional geological framework. When the expansion regions of different growth points meet for the first time, the expansion stops, and the line connecting the meeting points is used as the partition boundary line; A closed area enclosed by the boundary lines of each partition is a modeling unit, and each modeling unit contains only one sequence transition point.

5. The method for three-dimensional modeling of coal mines with complex geology as described in claim 1, characterized in that: The delineation of radiation and stability regions using sequence transition points is described below: A circular region is defined as the radiation zone, with the sequence transition point as the geometric center and the spatial range of the coal seam where the sequence change occurs as the radius. The region outside the radiation zone is the stable zone. When the sequence transition point is a bifurcation transition point, the spatial range is the maximum distance from the bifurcation transition point along the extension direction of each branch to the position where the thickness of the main coal seam no longer decreases and the thickness of the interbedded gangue no longer increases in the adjacent borehole. When the sequence transition point is a merging transition point, the spatial range is the maximum distance from the merging transition point along the confluence direction to the position where the thickness of the interbedded gangue layer in the adjacent borehole first decreases to zero.

6. The method for three-dimensional modeling of coal mines with complex geology as described in claim 1, characterized in that: Determining the radiation direction includes the following: Within each modeling unit, the radiation direction is determined to radiate outward from the sequence transition point.

7. The method for three-dimensional modeling of coal mines with complex geology as described in claim 6, characterized in that: The construction of the radial topology relationship includes the following: Within the radiation zone, a radiation topology is constructed using sequence transition points as topological anchors: it is stipulated that coal seams undergo sequence changes at sequence transition points, and each stratification interface extends radially from the sequence transition point along a defined radiation direction.

8. The method for three-dimensional modeling of coal mines with complex geology as described in claim 7, characterized in that: The construction of layered interface surfaces within the radiation region using radiation topology includes the following: Within the radiation zone, the type of strata to be constructed is determined based on the type of sequence transition point. When the sequence transition point is a bifurcation transition point, the top and bottom interfaces of three sets of sequence units—upper strata, interbedded strata, and lower strata—need to be constructed. When the sequence transition point is a merging transition point, the top and bottom interfaces of two sets of sequence units—upper branch strata and lower branch strata—need to be constructed. Starting from the sequence transition point and extending outward along the radial direction, the layer thickness varies linearly with distance: when the sequence transition point is a bifurcation transition point, for any point within the radiation zone, the layer thickness increases with the distance from that point to the bifurcation transition point. The specific expression for layer thickness is as follows: ,in The target thickness at the boundary of the radiation zone is defined by the layer, where R represents the radius of the radiation zone and d represents the distance from the bifurcation transition point. When the sequence transition point is a merging transition point, for any point within the radiation region, the layer thickness decreases as the distance from that point to the merging transition point increases. The specific expression for layer thickness is as follows: , R represents the normal thickness of the branch layer at the merging transition point, R represents the radius of the radiation zone, and d represents the distance from the merging transition point. The top and bottom elevations of each layer interface are determined based on the layer thickness and the elevation of the main coal seam interface. The corner points in the corner grid frame within the radiation zone are used as geometric constraint points. The top and bottom interface surfaces of each layer interface are constructed by surface fitting. During the surface fitting process, a common boundary constraint is applied: when the sequence transition point is a bifurcation transition point, the boundary of the upper layer bottom interface and the boundary of the intercalary layer top interface coincide at the sequence transition point, and the boundary of the intercalary layer bottom interface and the boundary of the lower layer top interface coincide at the sequence transition point. When the sequence transition point is a merging transition point, the bottom interface of the upper branch layer and the top interface of the lower branch layer coincide with the boundary of the main coal seam interface at the boundary of the radiation zone.

9. The method for three-dimensional modeling of coal mines with complex geology as described in claim 8, characterized in that: The construction of stable coal seam interface surfaces within the stable region includes the following: Within the stable region of the modeling unit, a corresponding stable interface surface is constructed based on the type of the sequence transition point: When the sequence transition point is a bifurcation transition point, the target thickness of the upper layer, the intercalated layer, and the lower layer at the boundary of the radiation zone is taken as the constant thickness in the stable zone. Based on the corner points in the corner grid frame located in the stable zone, the top and bottom interface surfaces of the upper layer, the intercalated layer, and the lower layer are constructed respectively. When the sequence transition point is a merging transition point, the corner points located in the stable zone in the corner grid frame are used as geometric constraint points, and the top and bottom interface surfaces of the main coal seam are constructed by triangulation.

10. The method for three-dimensional modeling of coal mines with complex geology as described in claim 1, characterized in that: The process of constructing the global three-dimensional geological model of the coal seam is as follows: The complete coal seam models of adjacent modeling units are aligned along their shared partition boundary line. The corner points of the grid frame on both sides of the partition boundary line are used as common geometric constraints to perform transition processing on the interface surfaces on both sides of the boundary. After completing the boundary alignment and transition processing of all adjacent modeling units, the complete coal seam models are merged into a global three-dimensional geological model of the coal seam.

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