A coal seam thickening zone identification method based on through-layer borehole information

Abstract

The application relates to a coal seam thickening zone identification method based on a through-layer drilling information, which is characterized in that: through systematic arrangement of construction account data, scattered information is collected into a unified through-layer drilling information table, through use of specific mine plane maps and profile maps, the accuracy of drilling coordinates is ensured, and the authenticity of the model is improved; then a series of coal points and coal exit points are calculated through a mathematical algorithm, a threshold value is set, a region with a coal seam thickening zone is judged and combed, the identification difficulty of small structures is reduced, and a mine gas control scheme is quickly formulated.

Description

Technical Field

[0001] This invention relates to the field of coal mine reserve prediction technology, and in particular to a method for identifying coal seam thickening zones based on cross-layer borehole information. Background Technology

[0002] With the widespread adoption and application of intelligent and unmanned mining technologies in my country, building smart mines is an inevitable trend in the future development of coal mines, and intelligent mining represents a new stage in the comprehensive mechanization of coal mining. Constructing accurate three-dimensional coal seam models is one of the key technologies for achieving intelligent mining. Currently, the construction of initial coal seam models is mainly based on data from boreholes, 3D seismic data, channel wave CT, and 3D roadway scanning. However, due to various factors such as the quantity of source data, source data processing, and the selection of interpolation methods, the initial three-dimensional coal seam models constructed using these data are inaccurate, have low vertical resolution, and generally exhibit large errors.

[0003] Currently, there are three commonly used methods for measuring coal thickness underground: underground borehole detection, transmission channel wave detection, and ground-penetrating radar detection. For transmission channel wave detection of coal thickness, when the coal thickness varies greatly, the selected tomographic imaging frequency begins to decrease relative to the coal thickness resolution, and the error of channel wave detection will be too large. For radar detection, in the radar grayscale image, the direct wave that separates the air from the coal seam is relatively obvious, but the boundary between the coal seam and the rock strata is not obvious, which limits the application of radar technology in coal seam thickness measurement. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a method for identifying coal seam thickening zones based on cross-layer borehole information. By collecting cross-layer borehole information and preprocessing the borehole information, and then setting thresholds after calculating the parameters of coal-encounter points and coal-exit points, the method can identify and sort out areas with coal seam thickening zones, reduce the difficulty of identifying small structures, and quickly formulate mine gas control plans.

[0005] The objective of this invention is achieved as follows:

[0006] A method for identifying coal seam thickening zones based on cross-layer borehole information includes the following:

[0007] S1. Organize and clean the drilling data of the bottom drainage roadway of the mine;

[0008] Collect the mine's ledger records, remove incomplete borehole data, and compile a list of data for each borehole, including the angle, dip angle, coal and rock conditions, and coal penetration length.

[0009] S2. Set up a three-dimensional coordinate system in the well and calculate the X, Y, and Z coordinates of each drilling point. The azimuth angle is 0° with the due north direction and the range of the azimuth angle is 0~360°. The horizontal direction is the dip angle with the range of -90~90°.

[0010] S3. Calculate the coordinates of the coal-seeking point X1, Y1, and Z1 by combining the dip angle and azimuth angle;

[0011] S4. Calculate the coal point coordinates X2, Y2, and Z2 by combining the dip angle and azimuth angle;

[0012] S5. Record all coal-seeking points as set 1 and all coal-exiting points as set 2. Measure the projected distance of each point in set 1 and other points on the XOY plane, and record it as L1. Similarly, measure each pair of coal-seeking points and each pair of coal-exiting points, and measure the projected distance L2 of each pair of coal-exiting points on the XOY plane.

[0013] S6. Based on the borehole layout distance, set the search radius P1, P1 = (1.2-1.5) × borehole spacing; then select each pair of coal-bearing points that meet L1 < P1.

[0014] S7. Calculate the height difference ΔZ1 for each pair of coal-seeking points, and find ΔZ1 / L1, denoted as K1;

[0015] S8. Calculate the height difference ΔZ2 for each pair of coal outlet points, and find ΔZ2 / L2, denoted as K2;

[0016] S9. Let |K1-K2| be M1. Based on parameters such as the height difference of the coal seam thickening zone and the search radius, set a threshold P2, where P2 = thickness difference of the coal seam thickening zone / search radius P1. Record and output each pair of coal extraction points where M1 > P2.

[0017] S10. Each pair of coal-bearing points output in step S9 above indicates the presence of a coal seam thickening zone between the two borehole sections, thus revealing the situation where the coal seam thickens in the area between the two boreholes.

[0018] Preferably, the X coordinate of the borehole in step S2 can be obtained from the mining plan of the mine working face, and the X coordinate obtained from the plan is the actual X coordinate of the borehole.

[0019] Preferably, the Y-coordinate of the borehole in step S2 can be obtained from the cross-sectional view of each borehole in the working face of the mine.

[0020] Preferably, the Z-coordinate of the borehole in step S2 can be obtained from the cross-sectional view of each borehole in the working face of the mine, and then the Z-coordinate can be corrected by the schematic diagram of the roadway centerline to obtain the true Z-coordinate of the borehole.

[0021] Preferably, in step S3, X1 = X + coal length × |cos dip angle| × cos azimuth angle, Y1 = Y + coal length × |cos dip angle| × sin azimuth angle, and Z1 = Z + coal length × sin azimuth angle.

[0022] Preferably, in step S4, X2 = X + coal discharge length × |cos inclination angle| × cos azimuth angle, Y2 = Y + coal discharge length × |cos inclination angle| × sin azimuth angle, and Z2 = Z + coal discharge length × sin azimuth angle.

[0023] Preferably, in step S9, for thin coal seams with a thickness of less than 1.3 meters, a thickness difference of 1 meter is considered as the thickening zone of the coal seam, and P2 is set to 0.1.

[0024] Preferably, in step S9, for medium-thick coal seams with a thickness of 1.3 to 3.5 meters, the 1.5-meter thickness difference is considered as the thickening zone of the coal seam, and P2 is set to 0.15.

[0025] Preferably, in step S9, for thick coal seams with a thickness of 3.5 to 10 meters, a thickness difference of 2 meters is considered as the thickening zone of the coal seam, and P2 is set to 0.2.

[0026] Preferably, after calculating the X, Y, and Z coordinates of each drilling point in step S2, the hole depth and coal-bearing section are processed and classified. Taking 0-82.5 rock-98.2 coal-100 rock as an example, 82.5~98.2 is the coal-bearing section, and the rest is the rock section. 82.5 is the coal-bearing length, and 98.2 is the coal-exiting length.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] This invention establishes a mathematical model based on borehole data through preprocessing. The high-precision calculation model reflects the potential thickening zone of the coal seam and identifies and reveals abrupt changes in coal thickness within the coal seam. It then rationally designs a construction plan, achieving successful treatment in one go and reducing the amount of engineering work. Attached Figure Description

[0029] Figure 1 This is a plan view of the mining face in Embodiment 1 of the present invention.

[0030] Figure 2 This is a cross-sectional view of each borehole in the mine working face according to Embodiment 1 of the present invention.

[0031] Figure 3 This is a schematic diagram of the tunnel centerline of Embodiment 1 of the present invention. Detailed Implementation

[0032] To better understand the technical solution of the present invention, a detailed description will be provided below in conjunction with relevant illustrations. It should be understood that the specific embodiments described below are not intended to limit the specific implementation of the technical solution of the present invention, but are merely possible implementations of the technical solution of the present invention. It should be noted that the descriptions of the positional relationships of the components herein, such as component A being located above component B, are based on the relative positions of the components in the illustrations and are not intended to limit the actual positional relationships of the components. Example 1

[0033] See Figures 1-3 , Figure 1 A mining plan of the working face in Embodiment 1 was drawn. As shown in the figure, the method for identifying coal seam thickening zones based on cross-layer borehole information in Embodiment 1 specifically includes the following:

[0034] S1. Collect data from cross-layer boreholes;

[0035] S1.1 Collect the drilling records of bottom drainage roadways in coal mines with thickened coal seams to be identified. The data for each borehole is shown in Table 1 below:

[0036]

[0037] Table 1

[0038] S1.2. Collect the X coordinates of the borehole. The X coordinates of the borehole can be obtained from the mining plan of the working face of the mine. The X coordinates obtained from the plan are the true X coordinates of the borehole.

[0039] S1.3. Collect the Y coordinates of the boreholes. The Y coordinates of the boreholes can be obtained from the cross-sectional views of each borehole in the working face of the mine. From the mining plan of the working face, it can be seen that the mine roadway is on a horizontal straight line. Therefore, the working face of the mine is located on the same XOY plane in space, so the Y coordinates of the boreholes do not need to be corrected.

[0040] S1.4. Collect the Z coordinates of the borehole. The Z coordinates of the borehole can be obtained from the cross-sectional diagram of each borehole in the working face of the mine. Then, the Z coordinates are corrected by the schematic diagram of the roadway centerline to obtain the true Z coordinates of the borehole.

[0041] S1.5. Calculate the coordinates X1, Y1, and Z1 of the coal-bearing point by combining the dip angle and azimuth angle;

[0042] X1 = X + Coal length × |cos dip angle| × cos azimuth angle, Y1 = Y + Coal length × |cos dip angle| × sin azimuth angle, Z1 = Z + Coal length × sin azimuth angle;

[0043] S1.6 Calculate the coordinates of the coal extraction point X2, Y2, Z2 by combining the dip angle and azimuth angle;

[0044] X2 = X + Coal discharge length × |cos dip angle| × cos azimuth angle, Y2 = Y + Coal discharge length × |cos dip angle| × sin azimuth angle, Z2 = Z + Coal discharge length × sin azimuth angle;

[0045] S1.7. List the cross-layer borehole data in Table 2. Based on the data in Table 1 above, as well as the borehole coordinates, coal-encounter point coordinates, and coal-exit point coordinates, compile the cross-layer borehole data in Table 2. (Except for the borehole coordinates X, Y, and Z, which can all be obtained from Table 1, the cross-layer borehole data is shown in Table 2 below:

[0046]

[0047] Table 2

[0048] S2. Record all coal-seeking points as set 1 and all coal-exiting points as set 2. Measure the projected distance of each point in set 1 and other points on the XOY plane, and record it as L1. Similarly, measure each pair of coal-seeking points and each pair of coal-exiting points, and measure the projected distance L2 of each pair of coal-exiting points on the XOY plane.

[0049] S3. Based on the borehole layout distance, set the search radius P1, where P1 = 1.2 × borehole spacing. To avoid errors caused by borehole position during construction, the value of P1 can be increased, with a maximum of 1.5 × borehole spacing. Then, select each pair of coal-bearing points that meet the condition L1 < P1.

[0050] S4. Calculate the height difference ΔZ1 for each pair of coal-seeking points, and find ΔZ1 / L1, denoted as K1;

[0051] S5. Calculate the height difference ΔZ2 for each pair of coal outlet points, and find ΔZ2 / L2, denoted as K2;

[0052] S6. Let |K1-K2| be M1. Based on parameters such as the height difference of the coal seam thickening zone and the search radius, set the threshold P2, where P2 = thickness difference of the coal seam thickening zone / search radius P1.

[0053] S6.1 For thin coal seams (coal seams with a thickness of less than 1.3 meters), a thickness difference of 1 meter can be considered as the thickening zone of the coal seam, and P2 is set to 0.1;

[0054] S6.2 For medium-thick coal seams (coal seams with a thickness of 1.3~3.5 meters), the 1.5-meter thickness difference can be considered as the thickening zone of the coal seam, and P2 is set to 0.15;

[0055] S6.3 For thick coal seams (coal seams with a thickness of 3.5 to 10 meters), a thickness difference of 2 meters can be considered as the thickening zone of the coal seam, and P2 is set to 0.2;

[0056] S6.4 Finally, record and output each pair of coal outlet points where M1 > P2;

[0057] S7 and steps S2 to S6 are implemented in the algorithm software. Each pair of coal-bearing points output indicates the presence of a coal seam thickening zone between the two borehole sections, thus obtaining the situation after the coal seam thickens in the area between the two boreholes.

[0058] In this embodiment, Python algorithm software is used for input calculation.

[0059] In this embodiment, the mine is divided into two areas: large holes and small holes. Since the spacing between the large holes on the plan is 10 meters, the search radius P1 in step eight is set to 12 meters. The spacing between the small holes on the plan is 2.5 meters, so the search radius P1 in step eight is set to 4 meters. The threshold P2 in step eleven is uniformly set to 0.20.

[0060] In this embodiment, coal seam thickening zones were identified from 1924 boreholes in the bottom drainage roadway of a certain mine working face. Through the above steps, a series of thresholds were set, and finally, coal seam thickening zones were detected between 146 pairs of boreholes, as shown in Table 3 below. Line and Line2 represent the output borehole numbers, Δz represents the height difference between two boreholes, and the area between each pair of boreholes in each row of the output is the coal seam thickening zone.

[0061]

[0062] Table 3

[0063] Working principle:

[0064] This invention provides a method for identifying coal seam thickening zones based on cross-layer borehole information. First, borehole data is extracted from the construction log and organized into a cross-layer borehole information table, including the X, Y, and Z coordinates of the boreholes. The X coordinate is directly obtained from the mining face plan; the Y coordinate does not need correction since the roadways are on the same horizontal plane; and the Z coordinate is corrected using a cross-sectional view and a schematic diagram of the roadway's central axis. Then, the coordinates of coal-bearing and coal-exit points are calculated using dip and azimuth angles, and these points are divided into two sets. By measuring the projection distance of the midpoint of each set onto the XOY plane and setting a search radius P1, pairs of coal-bearing points that meet the criteria are selected. Next, the ratio K1 of the height difference to the horizontal distance for each pair of coal-bearing points is calculated, along with the corresponding K2 for the coal-exit point. By comparing the difference M1 between K1 and K2 and setting a threshold P2, the region of coal seam thickening is finally determined. The above calculation method of this invention can be implemented using algorithm software, effectively identifying coal seam thickening regions and providing crucial geological information for coal mining.

[0065] The above are merely specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. All technical solutions formed by equivalent transformations or substitutions fall within the scope of protection of the present invention.

Claims

1. A method for identifying coal seam thickening zones based on cross-layer borehole information, characterized in that, Includes the following: S1. Organize and clean the drilling data of the bottom drainage roadway of the mine; Collect the mine's ledger records, remove incomplete borehole data, and compile a list of the azimuth, dip angle, coal and rock conditions, and coal penetration length of each borehole. S2. Set up a three-dimensional coordinate system in the well and calculate the X, Y, and Z coordinates of each drilling point. The azimuth angle is 0° with the due north direction and the range of the azimuth angle is 0~360°. The horizontal direction is the dip angle with the range of -90~90°. S3. Calculate the coordinates of the coal-seeking point X1, Y1, and Z1 by combining the dip angle and azimuth angle; S4. Calculate the coal point coordinates X2, Y2, and Z2 by combining the dip angle and azimuth angle; S5. Record all coal-seeking points as set 1 and all coal-exiting points as set 2. Measure the projected distance of each point in set 1 and other points on the XOY plane, and record it as L1. Similarly, measure each pair of coal-seeking points and each pair of coal-exiting points, and measure the projected distance L2 of each pair of coal-exiting points on the XOY plane. S6. Based on the borehole layout distance, set the search radius P1, P1 = (1.2-1.5) × borehole spacing; then select each pair of coal-bearing points that meet L1 < P1. S7. Calculate the height difference ΔZ1 for each pair of coal-seeking points, and find ΔZ1 / L1, denoted as K1; S8. Calculate the height difference ΔZ2 for each pair of coal outlet points, and find ΔZ2 / L2, denoted as K2; S9. Let |K1-K2| be M1. Based on the height difference of the coal seam thickening zone and the search radius parameter, set the threshold P2, where P2 = thickness difference of the coal seam thickening zone / search radius P1. Record and output each pair of coal extraction points where M1 > P2. Each pair of coal extraction points output in steps S10 and S9 indicates the presence of a thickened coal seam zone between the two borehole sections, thus revealing the situation where the coal seam thickens in the area between the two boreholes.

2. The method for identifying coal seam thickening zones based on cross-layer borehole information according to claim 1, characterized in that: In step S2, the X coordinate of the borehole is obtained from the mining plan of the working face of the mine. The X coordinate obtained from the plan is the actual X coordinate of the borehole.

3. The method for identifying coal seam thickening zones based on cross-layer borehole information according to claim 1, characterized in that: The Y-coordinate of the borehole in step S2 is obtained from the cross-sectional view of each borehole in the working face of the mine.

4. The method for identifying coal seam thickening zones based on cross-layer borehole information according to claim 1, characterized in that: In step S2, the Z coordinate of the borehole is obtained from the cross-sectional view of each borehole in the working face of the mine. Then, the Z coordinate is corrected by the schematic diagram of the roadway centerline, thus obtaining the true Z coordinate of the borehole.

5. The method for identifying coal seam thickening zones based on cross-layer borehole information according to claim 1, characterized in that: In step S3, X1 = X + coal seam length × |cos dip angle| × cos azimuth angle, Y1 = Y + coal seam length × |cos dip angle| × sin azimuth angle, and Z1 = Z + coal seam length × sin azimuth angle.

6. The method for identifying coal seam thickening zones based on cross-layer borehole information according to claim 1, characterized in that: In step S4, X2 = X + coal discharge length × |cos dip angle| × cos azimuth angle, Y2 = Y + coal discharge length × |cos dip angle| × sin azimuth angle, and Z2 = Z + coal discharge length × sin azimuth angle.

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