Rock burst and mine earthquake collaborative treatment method based on regional fracturing

Abstract

The invention provides a rock burst and mine earthquake collaborative treatment method based on regional fracturing, and the method comprises the following steps: selecting a working surface, determining a plurality of rock burst control layers with rock burst risks, then determining a plurality of mine earthquake control layers with mine earthquake risks, and determining a plurality of mine earthquake control layers with mine earthquake risks; performing main control layer analysis on all the rock burst control layers in the fissure zone preferentially to determine a multi-stage rock burst main control layer, performing main control layer analysis on all the mine earthquake control layers above the fissure zone to determine a multi-stage mine earthquake main control layer, and performing logging correction analysis; according to the length and width of the working face, the thickness of the rock burst control layer and the number of the mine earthquake control layers, the layout design of separate layer fracturing is determined, the treatment method achieves comprehensive prevention and control of the mine area risk, the treatment effect on the rock burst and the mine earthquake is remarkable, the disaster risk is reduced, and a powerful guarantee is provided for mine safety production.

Description

Technical Field

[0001] The present invention belongs to the technical field of safe mining of coal mines, and in particular relates to a method for collaboratively controlling rock burst and mine earthquakes based on regional fracturing. Background Art

[0002] The coal seams in the mining area are covered with multiple layers of extremely thick, hard roof (50-300m thick). Their high strength and intact structure lead to the formation of suspended roofs in the low-lying roofs of the goaf, resulting in stress concentration and easily inducing rock bursts. The high-lying roofs form large-scale spatial structures, which, when unstable, can produce strong mining tremors. Among related technologies, regional fracturing technology is widely used to treat the weakening of hard roofs. Horizontal wells and vertical wells, as two independent processes, have the following complementary defects:

[0003] Horizontal well fracturing: By placing horizontal wells along the strike of the coal seam, continuous fracturing can be achieved on a flat surface, providing wide coverage and good fracture network connectivity. This significantly reduces the probability of forming blind and inadequate fracturing zones, effectively weakening the mid- and low-level roofs and eliminating overhanging roof structures, significantly preventing and controlling rock bursts. However, due to the limitations of the wellbore trajectory, horizontal wells can only fractur e a single layer and cannot simultaneously transform the multiple layers of high-level roof above the fault zone, making it difficult to suppress mine earthquake disasters caused by high-level roof instability.

[0004] Surface vertical well fracturing: Vertical drilling can be used to perform layered fracturing on the high, thick, and hard roof at different levels above the coal seam, disrupting its integrity and preventing the formation of large-scale spatial structures, thereby reducing the risk of mine tremors. However, vertical well fracturing has a limited planar coverage area, and the direction of crack propagation is controlled by ground stress. This can easily lead to the formation of fracturing blind spots at the edges of the area, resulting in insufficient local roof pressure relief and making it difficult to completely eliminate the risk of rock burst in the mid- and low-level roof.

[0005] Therefore, the use of either horizontal or vertical wells alone cannot address the coordinated prevention and control needs of both rock burst and mine tremors. The planar continuity of horizontal wells and the vertical multi-layer reconstruction capabilities of vertical wells are highly complementary, but existing technologies have yet to propose a combined well layout and process matching method for both, resulting in insufficient coordinated weakening of roof stratification. Summary of the Invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, an embodiment of the present invention proposes a method for collaboratively controlling rock burst and mine tremors based on regional fracturing. The control method achieves comprehensive prevention and control of mining area risks, has significant effects on controlling rock burst and mine tremors, reduces disaster risks, and provides strong guarantees for safe production in mines.

[0008] The method for collaboratively controlling rock burst and mine tremors based on regional fracturing according to an embodiment of the present invention includes the following steps:

[0009] S1. Based on 3D seismic exploration, drill core and microseismic positioning analysis, a stratigraphic model of the mining area is established and the working face is selected;

[0010] By using the key layer theory, we first determine all the rock burst control layers within the fracture zone in the mining area stratigraphic model that have rock burst risks.

[0011] Then, several mine earthquake control layers with mine earthquake risk above the fracture zone in the mine area stratigraphic model are determined;

[0012] Furthermore, the key layers with rock burst risk and mine tremor risk within the caving zone and fracture zone are regarded as rock burst control layers;

[0013] S2. Prioritize the analysis of the primary control layer for all rock burst control layers within the fracture zone. Develop a step-by-step determination and management analysis principle for all rock burst control layers. Eliminate other rock burst control layers that will not pose a rock burst risk after the current rock burst control layer is managed. Determine a multi-level primary rock burst control layer from all rock burst control layers.

[0014] S3. Conduct a master control layer analysis on all mine earthquake control layers above the fracture zone, formulate a step-by-step determination and management analysis principle for the mine earthquake control layers, eliminate mine earthquake control layers that cannot produce disaster-causing effects after being managed, and determine multiple levels of mine earthquake master control layers from all mine earthquake control layers;

[0015] S4. Perform well logging correction analysis and dynamically correct the positions of target rock layers of the multi-level rock burst main control layer and the multi-level mine earthquake main control layer;

[0016] S5. Determine the layout design of layered fracturing based on the length and width of the working face, the thickness of the rock burst control layer, and the number of mine seismic control layers. The layered fracturing layout design includes: a combined fracturing method of surface vertical wells and underground horizontal wells, a fracturing method of surface multi-layer horizontal wells, a combined fracturing method of surface horizontal wells and surface vertical wells, and a fracturing method of surface vertical wells.

[0017] The method for coordinated management of rock burst and mine earthquake based on regional fracturing in an embodiment of the present invention performs simultaneous analysis and determination of multiple rock burst control layers and multiple mine earthquake control layers in the same modeling, and takes the mine earthquake control layers falling within the two zones as rock burst control layers for management analysis, and determines the multi-level rock burst main control layers and the multi-level mine earthquake main control layers step by step. By simulating and analyzing the multi-level rock burst main control layers and the multi-level mine earthquake main control layers, multi-level energy release is achieved, and control layers that do not need to be managed are eliminated, while achieving comprehensive coverage of the rock burst main control layers and efficient determination of the mine earthquake main control layers. The main control layers are dynamically corrected again through well logging analysis, and the determination of the main control layers in the coordinated prevention and control of rock burst and mine earthquake is assisted and corrected from a management perspective.

[0018] The method for coordinated management of rock burst and mine earthquake based on regional fracturing of the present invention also adopts a variety of layered fracturing well layout methods, which not only realizes continuous fracturing on the plane and multi-layer transformation in the vertical direction, effectively reduces the risk of fracturing blind spots and insufficient pressure relief, but also improves the coverage range, reduces the limitations of the crack expansion direction, and avoids the formation of fracturing blind spots.

[0019] Furthermore, the well placement and fracturing method can be flexibly selected based on specific geological conditions and risk strata, improving the adaptability of the treatment plan. The overall solution takes into account the coordinated prevention and control of rock bursts and mine tremors, reducing the disaster risk in the mining area and ensuring production safety and the safety of miners.

[0020] In some embodiments, in step S1, determining the rock burst control layer includes the following steps:

[0021] S111. Calculate the energy released by the breaking of the current key layer;

[0022] S112, analyzing the energy measured by each sensor in historical rock burst cases in the current area to determine the vibration energy attenuation law;

[0023] S113. Calculate the remaining energy transferred to the working face based on the energy released by the breaking of the key layer and the vibration energy attenuation law;

[0024] S114. Based on the analysis of energy accumulation, transfer, release and dissipation after mining, a residual energy induced shock risk assessment system is established to determine the shock induction conditions, and the rock layer whose residual energy meets the shock induction conditions is determined as the rock burst control layer.

[0025] In some embodiments, in step S1, determining the mine earthquake control layer includes the following steps:

[0026] S121. Determine the mine earthquake control layer that has a mine earthquake disaster impact on the underground mining working face;

[0027] Calculate the energy released by the breaking of the current key layer; and determine the vibration energy attenuation law by analyzing the actual energy measured by each sensor in historical mine earthquake cases in the current area. Based on the energy released by the breaking of the key layer and the vibration energy attenuation law, calculate the residual energy transmitted to the working face, and use the residual energy to assess the risk of mine earthquake induced shock. The rock layer whose residual energy meets the conditions for induced shock is determined as the mine earthquake control layer;

[0028] S122. Determine the mine earthquake control layer that has a disaster-causing impact on the ground;

[0029] Vibration velocity monitoring sensors are arranged on the ground to monitor the speed at which mine earthquakes are transmitted to the surface. The maximum vibration velocity of different rock strata is obtained through theoretical analysis. The mine earthquake intensity levels corresponding to different strata are determined based on the maximum vibration velocity of the rock strata at different strata. The mine earthquake control layer with a mine earthquake intensity level of II or above is determined as the mine earthquake control layer.

[0030] In some embodiments, in step S2 and step S3, the step-by-step determination and control analysis principles for multiple rock burst control layers or multiple mine tremor control layers include:

[0031] Compare the residual energies of multiple rock burst control layers or multiple mine seismic control layers, and use the rock burst control layer or mine seismic control layer with the largest residual energy transmitted to the working face as the primary rock burst main control layer or the primary mine seismic main control layer, and conduct a control analysis on the primary rock burst main control layer or the primary mine seismic control layer;

[0032] Repeat step S1 to assess rock burst risk or mine tremor risk for other control layers adjacent to the controlled main control layer, eliminate rock burst control layers or mine tremor control layers that no longer have rock burst risk or mine tremor risk, and select rock burst control layers or mine tremor control layers adjacent to the controlled main control layer that still have induced rock burst risk or mine tremor risk as the next level of controlled disaster-causing main control layer;

[0033] This step is repeated until there is no more risk of mine earthquake disaster or rock burst disaster in other key layers, thus forming a multi-level rock burst main control layer or a multi-level mine earthquake main control layer.

[0034] In some embodiments, in steps S2 to S4, each level of rock burst main control layer or each level of mine earthquake main control layer is treated by fracturing or blasting;

[0035] The mechanical properties of the rock burst main control layer or the mine earthquake main control layer after being controlled are weakened. During the control analysis, it is necessary to analyze the attenuation effect and structural regulation effect of the coordinated rock burst main control layer or the mine earthquake main control layer after being controlled, so as to eliminate the rock burst control layer or the mine earthquake control layer that no longer has rock burst risk or mine earthquake risk.

[0036] In some embodiments, in steps S2 to S4, when there are multiple layers of thick hard roof in the mine, in the process of step-by-step determination and management analysis of the multi-level mine earthquake main control layers or the multi-level rock burst main control layers, the number of layers for fracturing management should be determined based on the position of the disaster-causing rock layer.

[0037] In some embodiments, in step S5, determining the layout design of the layered fracturing further includes the following steps:

[0038] Determine the mine geological conditions and fracturing construction parameters, estimate the expansion of the mine fracturing network, collect working face width information and strike length information, analyze the development of lateral mining-induced cracks in the working face, and estimate the construction length of surface vertical wells, underground horizontal wells, surface vertical wells, surface horizontal wells, and multi-layer horizontal wells.

[0039] In some embodiments, in a working face with a width of less than 350 m, the implementation of the combined well fracturing method of surface vertical wells and downhole horizontal wells includes the following steps:

[0040] According to the estimated fracturing information of the horizontal well and the fracturing range of the vertical well, the horizontal well construction information is determined, and the impact rock pressure control layer is fracturing constructed based on the horizontal well construction information. The underground horizontal well is located between the ground vertical well and the working face tunnel.

[0041] In some embodiments, in a working face with a width greater than or equal to 350 m, the implementation of the combined well fracturing method of surface vertical wells and downhole horizontal wells includes the following steps:

[0042] The horizontal well construction information is determined according to the estimated fracturing information of the horizontal well and the fracturing range of the vertical well, and the rock burst control layer is subjected to fracturing construction based on the horizontal well construction information. The downhole horizontal well is arranged between the ground vertical well and the tunnel of the working face; wherein, the vertical well construction information includes the number of the ground vertical wells, and the number of the ground vertical wells is multiple, and the multiple ground vertical wells are divided into at least two vertical well groups, and at least two of the vertical well groups are arranged at intervals along the inclination of the working face to be mined.

[0043] In some embodiments, the implementation of the multi-layer horizontal well fracturing method further includes the following steps:

[0044] A first well group and a second well group are arranged at intervals in the inclination direction of the working face, the first well group includes a first low-level horizontal well and a first high-level horizontal well arranged at intervals in the direction of the coal seam height, the second well group includes a second low-level horizontal well and a second high-level horizontal well arranged at intervals in the direction of the coal seam height, the extension direction of the fracture range formed by the fracturing of the first low-level horizontal well coincides with the extension direction of the fracture range formed by the fracturing of the second low-level horizontal well, the extension direction of the fracture range formed by the fracturing of the first high-level horizontal well coincides with the extension direction of the fracture range formed by the fracturing of the second high-level horizontal well, and the fracture range formed by the fracturing of the first low-level horizontal well is located below the fracture range formed by the fracturing of the first high-level horizontal well.

[0045] In some embodiments, the implementation of the combined well fracturing method of surface horizontal wells and surface vertical wells further includes the following steps:

[0046] A joint well group is constructed, wherein the joint well group includes a ground horizontal well and multiple vertical wells.

[0047] Before excavation and mining at the first mining face, in the first mining face and the second mining face, horizontal wells are arranged in the coal pillar area between the first mining face and the second mining face and in one of the second mining faces, and fracturing operations are carried out. In the second mining face, multiple vertical wells are constructed along the direction of the mining face and fracturing operations are carried out.

[0048] Alternatively, after the first mining face is excavated and mined, horizontal wells are arranged along the direction of the second working face and hydraulic fracturing is carried out. Multiple vertical wells are constructed along the direction of the working face and hydraulic fracturing is carried out.

[0049] There are multiple combined well layout groups, and the multiple combined well layout groups are arranged in sequence along the inclination of the working face.

[0050] In some embodiments, when the rock burst control layer and the mine shock control layer are unstable and the number of fracturing layers exceeds three, the construction of the surface vertical well fracturing method further includes the following steps:

[0051] A plurality of ground vertical wells are arranged in sequence along the strike direction of the working face on the ground, and a staged fracturing process is used to implement fracturing on each thick hard roof plate. The method also includes a plurality of ground vertical well groups, one of which includes the plurality of ground vertical wells, and the plurality of ground vertical well groups are arranged at intervals along the dip direction of the working face.

[0052] In some embodiments, the following steps are further included:

[0053] S5. During the fracturing and production periods, monitor and evaluate the regional fracturing and pressure relief effects to effectively guide the optimization of the regional fracturing plan;

[0054] S6. Select evaluation factors when rock burst occurs at the mining face, draw a basic base map of the mining face in a preset drawing software, and compile a rock burst prevention and control effect tracking and evaluation map based on the collected relevant data. Based on the rock burst prevention and control effect tracking and evaluation map, analyze the roof lithologic characteristics, cloud pressure pattern, ground subsidence, completed pressure relief projects and mining intensity to predict the rock burst hazard level of the mining face at different time periods. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of some method steps of the method for collaboratively controlling rock burst and mine earthquake based on regional fracturing according to the present invention;

[0056] Figure 2 1. It is a schematic diagram of the steps of a method for determining a main control layer of rock burst according to a method for coordinating rock burst and mine earthquake control based on regional hydraulic fracturing according to the present invention;

[0057] Figure 3 Schematic diagram of the steps of a method for determining a main controlling layer of mine earthquakes according to a method for coordinating rock burst and mine earthquakes based on regional hydraulic fracturing of the present invention;

[0058] Figure 4 Schematic diagram of the initial fracture induction of low-lying thick hard roof according to the method for coordinating rock burst and mine earthquake control based on regional fracturing of the present invention;

[0059] Figure 5 Schematic diagram of the rock burst and mine earthquake coordinated control method based on regional fracturing of the present invention;

[0060] Figure 6 It is a schematic diagram of the analysis of the control of a certain level of rock burst main control layer or a certain level of mine earthquake main control layer according to the method for coordinated control of rock burst and mine earthquake based on regional fracturing of the present invention;

[0061] Figure 7 It is a schematic diagram of determining and analyzing the next level of rock burst control layer or the next level of mine earthquake control layer after a certain level of rock burst control layer or a certain level of mine earthquake control layer is controlled in the method for coordinated rock burst control and mine earthquake control based on regional fracturing according to the present invention;

[0062] Figure 8 2. It is a schematic diagram of a maximum vibration velocity-distance curve corresponding to rock burst according to the method for coordinating rock burst and mine earthquake control based on regional fracturing according to the present invention;

[0063] Figure 9 2. It is a schematic diagram of a maximum vibration velocity-distance curve corresponding to a mine earthquake according to the method for coordinating rock burst pressure and mine earthquake control based on regional hydraulic fracturing of the present invention;

[0064] Figure 10 1 is a schematic plan view of a surface vertical well and an underground horizontal well according to an embodiment of the present invention;

[0065] Figure 11 is a cross-sectional view of a surface vertical well and an underground horizontal well according to an embodiment of the present invention;

[0066] Figure 12 It is a schematic plan view of a method for combining surface vertical wells and underground horizontal wells according to an embodiment of the present invention;

[0067] Figure 13 is a cross-sectional view of a method for combining surface vertical wells and underground horizontal wells according to an embodiment of the present invention;

[0068] Figure 14 Schematic diagram of the implementation (top view) of the surface multi-horizontal well layout method according to an embodiment of the present invention;

[0069] Figure 15 Schematic diagram of the implementation (side view) of the method for deploying multiple horizontal wells on the ground according to an embodiment of the present invention;

[0070] Figure 16 This is a schematic diagram (top view) of an implementation method for combining horizontal and vertical wells on the ground according to an embodiment of the present invention;

[0071] Figure 17 This is a schematic diagram (side view) of an implementation method for combining horizontal and vertical wells on the ground according to an embodiment of the present invention;

[0072] Figure 18 This is a schematic diagram (top view) of an implementation method for combining horizontal and vertical wells on the ground according to another embodiment of the present invention;

[0073] Figure 19 A flowchart of a method for evaluating regional fracturing effects based on microseismic monitoring provided by the present invention;

[0074] Figure 20 This is the layout diagram of microseismic probes in the regional fracturing and mining working face;

[0075] Figure 21 This is a schematic diagram of the distribution of microseismic events in unfractured and fractured areas;

[0076] Figure 22 1 is a flow chart of a method for tracking and evaluating rock burst prevention and control effects provided by an embodiment of the present invention;

[0077] Figure 23 This is an example diagram of a graph for tracking and evaluating rock burst prevention and control effects provided by an embodiment of the present invention;

[0078] Figure 24It is a schematic diagram of the overall method steps of the method for coordinated control of rock burst and mine earthquake based on regional fracturing according to the present invention.

[0079] Reference numerals:

[0080] 100, coal seam; 200, coal pillar; 2-1 microseismic probe;

[0081] 1. Mined working face;

[0082] 2. Working face to be mined; 21. Auxiliary transport roadway; 22. Rubber transport roadway;

[0083] 3. Surface vertical well; 31. Vertical well fracturing range; 32. Vertical well fracturing point; 33. First vertical well; 34. Second vertical well; 35. Vertical well fracturing point;

[0084] 4. Downhole horizontal well; 41. Estimated fracturing range of horizontal well; 411. First boundary; 412. Second boundary; 413. Third boundary; 414. Fourth boundary; 42. Fracturing point of horizontal well;

[0085] 5. First well group; 51. First low-level horizontal well; 52. First high-level horizontal well;

[0086] 6. Second well group; 61. Second lowest horizontal well; 62. Second highest horizontal well.

[0087] 7. Surface horizontal wells;

[0088] 81. First mining face; 82. Second mining face; 83. Third mining face. DETAILED DESCRIPTION

[0089] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0090] As shown in the figure, the method for collaboratively controlling rock burst and mine earthquake based on regional fracturing according to an embodiment of the present invention includes the following steps:

[0091] S1. Based on 3D seismic exploration, drill core analysis, and microseismic location analysis, a stratigraphic model of the mining area is established and the working face is selected. As can be seen, the stratigraphic model established using one or a combination of these methods can provide a comprehensive understanding of the mining area's geological structure, accurately identify strata at risk of rock burst and mine tremors, and provide a scientific basis for subsequent remediation efforts. This improves the accuracy of identifying risky strata and facilitates the development of targeted remediation plans.

[0092] Through the key layer theory, the key layers distributed within and above the fracture zone are determined; first, all the rock burst control layers with rock burst risks within the fracture zone in the mining area stratigraphic model are determined, that is, the key layers located within the fracture zone in the mining area stratigraphic model are determined as rock burst control layers.

[0093] Then, several mine earthquake control layers with mine earthquake risks above the fracture zone in the mining area stratigraphic model are determined, that is, several key layers located above the fracture zone in the mining area stratigraphic model and with mine earthquake risks are determined as mine earthquake control layers; and the key layers with rock burst risks and mine earthquake risks within the caving zone and fracture zone are all regarded as rock burst control layers.

[0094] S2. Prioritize the main control layer analysis of all rock burst control layers within the fracture zone, formulate a step-by-step determination and management analysis principle for all rock burst control layers, eliminate other rock burst control layers that do not have rock burst risks after the current rock burst control layer is managed, and determine the multi-level rock burst main control layer from all rock burst control layers.

[0095] S3. Conduct a main control layer analysis on all mine earthquake control layers above the fracture zone, formulate a step-by-step determination and management analysis principle for the mine earthquake control layers, eliminate the mine earthquake control layers that cannot produce disaster-causing effects after being managed, and determine multiple levels of mine earthquake main control layers from all mine earthquake control layers.

[0096] S4. Perform well logging correction analysis and dynamically correct the positions of the target rock layers of the multi-level rock burst main control layer and the multi-level mine earthquake main control layer.

[0097] S5. Determine the layout design of layered fracturing based on the length and width of the working face, the thickness of the rock burst control layer, and the number of mine seismic control layers. The layered fracturing layout design includes: a combined fracturing method of surface vertical wells and underground horizontal wells, a fracturing method of surface multi-layer horizontal wells, a combined fracturing method of surface horizontal wells and surface vertical wells, and a fracturing method of surface vertical wells.

[0098] Therefore, the rock burst and mine earthquake coordinated control method based on regional fracturing in the embodiment of the present invention performs synchronous analysis and determination of multiple rock burst control layers and multiple mine earthquake control layers in the same modeling, and takes the mine earthquake control layers falling within the two belts as rock burst control layers for control analysis, and determines the multi-level rock burst main control layers and the multi-level mine earthquake main control layers step by step. Through the simulation control analysis of the multi-level rock burst main control layers and the multi-level mine earthquake main control layers, multi-level energy release is realized, and the control layers that do not need to be controlled are eliminated, while achieving comprehensive coverage of the rock burst main control layers and efficient determination of the mine earthquake main control layers; and the main control layers are dynamically corrected again through well logging analysis, to assist in correcting the determination of the main control layers in the coordinated prevention and control of rock burst and mine earthquake from a control perspective.

[0099] The method for coordinated management of rock burst and mine earthquake based on regional fracturing of the present invention also adopts a variety of layered fracturing well layout methods, which not only realizes continuous fracturing on the plane and multi-layer transformation in the vertical direction, effectively reduces the risk of fracturing blind spots and insufficient pressure relief, but also improves the coverage range, reduces the limitations of the crack expansion direction, and avoids the formation of fracturing blind spots.

[0100] Furthermore, the well placement and fracturing method can be flexibly selected based on specific geological conditions and risk strata, improving the adaptability of the treatment plan. The overall solution takes into account the coordinated prevention and control of rock bursts and mine tremors, reducing the disaster risk in the mining area and ensuring production safety and the safety of miners.

[0101] According to the attached Figures 1-9 The following examples are described.

[0102] In some embodiments, in step S1, determining the rock burst control layer includes the following steps:

[0103] S111. Calculate the energy released by the breaking of the current key layer;

[0104] S112, analyzing the energy measured by each sensor in historical rock burst cases in the current area to determine the vibration energy attenuation law;

[0105] S113. Calculate the remaining energy transferred to the working face based on the energy released by the breaking of the key layer and the vibration energy attenuation law;

[0106] S114. Based on the analysis of energy accumulation, transfer, release and dissipation after mining, a residual energy induced shock risk assessment system is established to determine the shock induction conditions. The rock formations whose residual energy meets the shock induction conditions are identified as the main rock formations controlling rock pressure.

[0107] In some embodiments, in step S1, determining the mine earthquake control layer includes the following steps:

[0108] S121. Determine the mine earthquake control layer that has a mine earthquake disaster impact on the underground mining face;

[0109] Calculate the energy released by the breaking of the current key layer; and determine the vibration energy attenuation law by analyzing the actual energy measured by each sensor in historical mine earthquake cases in the current area. Based on the energy released by the breaking of the key layer and the vibration energy attenuation law, calculate the residual energy transmitted to the working face, and use the residual energy to assess the risk of mine earthquake induced shock. The rock layer whose residual energy meets the conditions for induced shock is determined as the mine earthquake control layer;

[0110] S112. Determine the mine earthquake control layer that has a disaster-causing impact on the ground;

[0111] Vibration velocity monitoring sensors are arranged on the ground to monitor the speed transmitted to the surface when a mine earthquake occurs, and the maximum vibration velocity of different rock strata is obtained through theoretical analysis. The mine earthquake intensity levels corresponding to different strata are determined according to the maximum vibration velocity of rock strata at different levels. The mine earthquake control layer with a mine earthquake intensity level of II or above is determined as the mine earthquake control layer, and the vibration velocity corresponding to the mine earthquake intensity level of II is greater than 2.59×10-3m / s; among them, the mine earthquake intensity is determined in accordance with GB / T17742-2020.

[0112] In some embodiments, in step S2 and step S3, referring to Figures 6 and 7 , the principles for step-by-step determination and management analysis of multiple rock burst control layers or multiple mine earthquake control layers include:

[0113] Compare the residual energies of multiple rock burst control layers or multiple mine seismic control layers, and use the rock burst control layer or mine seismic control layer with the largest residual energy transmitted to the working face as the primary rock burst main control layer or the primary mine seismic main control layer, and conduct a control analysis on the primary rock burst main control layer or the primary mine seismic control layer;

[0114] Repeat step S1 to assess rock burst risk or mine tremor risk for other control layers adjacent to the controlled main control layer, eliminate rock burst control layers or mine tremor control layers that no longer have rock burst risk or mine tremor risk, and select rock burst control layers or mine tremor control layers adjacent to the controlled main control layer that still have induced rock burst risk or mine tremor risk as the next level of controlled disaster-causing main control layer;

[0115] This step is repeated until there is no more risk of mine earthquake disaster or rock burst disaster in other key layers, thus forming a multi-level rock burst main control layer or a multi-level mine earthquake main control layer.

[0116] More specifically, when determining the multi-level rock burst master control layer step by step:

[0117] In the mining area stratum model, the rock burst control layer with the largest residual energy transferred to the working face was selected as the primary rock burst control layer, and a simulation analysis of the control of the primary rock burst control layer was conducted.

[0118] After the primary rock burst main control layer is controlled, the rock burst risk of the remaining rock burst control layers above and below the primary rock burst main control layer is assessed, and the rock burst control layers that still have the risk of inducing rock burst are identified as secondary rock burst main control layers.

[0119] This step is repeated until the N-level rock burst main control layer is determined. After the N-level rock burst main control layer is controlled, there is no longer any risk of rock burst inducing key layers within the two zones.

[0120] In some embodiments, in the process of determining the multi-level mine earthquake main control layer, it also includes: giving priority to the step-by-step determination and analysis of the mine earthquake control layer that causes mine earthquake disasters in the underground mining working face, and then adding the step-by-step determination and analysis of the mine earthquake control layer that causes ground mine earthquake disasters, to form a multi-level mine earthquake main control layer with unified sorting.

[0121] More specifically, when determining the main control layers of multiple mine earthquakes step by step:

[0122] Prioritize the control layer that causes the risk of mine shock in the underground mining working face by conducting a step-by-step analysis and determination. In the mining area stratigraphic model, the mine shock control layer with the largest residual energy transmitted to the working face is selected as the first-level mine shock control layer, and a control simulation analysis is conducted on the first-level mine shock control layer.

[0123] After the first-level mine earthquake main control layer is controlled, the mine earthquake risk is assessed for the remaining mine earthquake control layers above and below the first-level mine earthquake main control layer. The mine earthquake control layer that still has the risk of inducing mine earthquakes is determined as the second-level mine earthquake main control layer. This step is repeated until the N-level mine earthquake main control layers that can cause underground mine earthquakes are determined.

[0124] Consideration is introduced for the mine earthquake control layer that causes the risk of surface mine earthquakes. After conducting a step-by-step management analysis of the N-level mine earthquake main control layers that cause underground mine earthquakes, a mine earthquake main control layer analysis is conducted on the mine earthquake main control layer that is adjacent to the last level of the N-level mine earthquake main control layers and that can cause surface mine earthquake disasters. The mine earthquake main control layer analysis is performed according to step S122, and this step is repeated until the level n mine earthquake main control layer that can cause surface mine earthquakes is determined.

[0125] The N+n level mine earthquake main control layer is determined step by step, and the N+n level mine earthquake main control layer is arranged step by step according to the determined order. After the N+n level mine earthquake main control layer is governed and analyzed, the mine earthquake control layer outside the two zones no longer has the risk of inducing mine earthquakes.

[0126] In some embodiments, in step S111 and step S121, the calculation of the energy released by the breaking of the key layer includes calculating the elastic energy released by the initial breaking of the key layer and the elastic energy released by the periodic breaking, and obtaining the energy of the key layer at different heights from the working surface. Figures 4 and 5 Taking the low-position thick hard roof as an example, the impact load analysis of the initial fracture induction and periodic fracture induction of the key layer was carried out.

[0127] In some embodiments, the elastic energy released when the key layer breaks for the first time is calculated. The elastic energy released when the key layer breaks for the first time is calculated as follows:

[0128]

[0129] Where U dc To release elastic energy for the initial breaking of the basic top;

[0130] q dc The unit length converted load is the deadweight of the basic roof and the additional load of the overlying rock strata;

[0131] E d is the elastic modulus of the beam of the basic top;

[0132] R t is the tensile strength of the basic top rock layer;

[0133] h d is the thickness of the basic top;

[0134] b dc It is the suspended span when the basic top is first broken.

[0135] In some embodiments, the elastic energy released by periodic rupture of the key layer is calculated. The elastic energy released by periodic rupture of the basic top of the thick layer is calculated as follows:

[0136]

[0137] Where U dz Release elastic energy for the basic top cycle break;

[0138] q dz The unit length converted load is the self-weight of the basic top cantilever beam model and the additional load of the overlying rock strata;

[0139] b dz It is the overhang span when the basic top cycle breaks;

[0140] E d is the elastic modulus of the beam of the basic top;

[0141] R t is the tensile strength of the basic top rock layer;

[0142] h d The thickness of the basic top.

[0143] In some embodiments, in step S112 and step S121, analyzing the energy measured by each sensor in historical rock burst cases or historical mining earthquake cases in the current region includes:

[0144] The vibration waves of rock burst or mining tremors occurring on the working face are measured at multiple measuring points to obtain the measured waveforms. A velocity-time history curve is then formed based on the measured waveforms. The velocity-time history curve is used to reflect the maximum vibration velocity of each sensor.

[0145] The displacement time history curve is obtained by integrating the velocity time history curve. The displacement time history curve is used to reflect the position change of the medium particle during the propagation of the shock wave.

[0146] Calculate the energy of the vibration wave at a certain measuring point. Based on the fact that the energy of the vibration wave at a certain point is proportional to the square of the maximum particle motion velocity at that point, calculate the energy of the vibration wave at a certain measuring point and establish the relationship equation between energy and the maximum particle motion velocity at a certain point:

[0147]

[0148] Where A0 is the maximum particle speed at a certain location;

[0149] C is the fitting coefficient;

[0150] E is the radiation energy of the shock wave;

[0151] The maximum vibration velocity-distance curve is obtained by arranging the energy calculation results of the vibration wave measurement points. The distance refers to the distance between each sensor and the earthquake source, such as Figure 8 and Figure 9 As shown in FIG, the vibration energy attenuation law of rock burst or mining earthquake is obtained from the maximum vibration velocity-distance curve.

[0152] In some embodiments, the residual energy is used to evaluate the risk of mine earthquake-induced shock in step S121 using the same method as step S114. When the residual energy-induced shock risk determination system is established in step S114, the system equation is established as follows:

[0153] E e +ΔE=E P +E r ;

[0154] Where, E e is the elastic deformation energy of coal rock mass before excavation;

[0155] ΔE is the deformation energy increment caused by mining disturbance;

[0156] E P The energy dissipated by plastic deformation and destruction of coal and rock mass after excavation;

[0157] E r is the remaining energy.

[0158] In some embodiments, determining the inducing condition in step S114 includes: P <E ε +ΔE, then E r >0, this is the energy source of rock burst. When all the remaining energy is converted into the kinetic energy of coal rock ejection, rock burst occurs.

[0159] In some embodiments, in step S4, well logging analysis is performed, and the target rock layer corresponding to the determined mine earthquake control layer is observed and measured through well logging to obtain rock properties, rock layer strength, sandstone content, and mud content factors, judge the fracturing ability of the target rock layer, and dynamically correct the target rock layer position of the rock layer that mainly controls the impact ground pressure during the treatment analysis stage.

[0160] In some embodiments, when performing the well logging analysis in step S4, the well logging analysis method includes resistivity logging, sonic logging and natural gamma logging, wherein:

[0161] Resistivity logging, the principle is: to determine the lithology and fluid properties by measuring the resistivity of the formation;

[0162] Specific technologies include:

[0163] Lateral logging technology emits focused current into the formation to reduce the impact of the wellbore and surrounding rock, and is suitable for high-resistivity formations;

[0164] Induction logging technology uses the principle of electromagnetic induction to measure formation conductivity and is suitable for wells with low resistivity or filled with conductive mud.

[0165] Acoustic logging measures the propagation velocity (time difference) and amplitude attenuation of acoustic waves in the formation to infer porosity and lithology. Acoustic waves propagate quickly in dense rocks (such as limestone and sandstone) and slowly in loose or porous rocks. The ratio of the longitudinal and transverse wave velocities can also be used to assess formation mechanical properties (such as fracture pressure).

[0166] The principle of natural gamma logging is to detect the natural radioactivity of the formation (mainly from potassium, uranium and thorium isotopes). Since mudstone has high radioactivity and sandstone and limestone have low radioactivity, it is used to analyze the lithologic composition, formation boundaries and mineral content.

[0167] In some embodiments, when a mudstone layer appears in the target rock layer corresponding to the main control horizon or the mud content of the rock layer exceeds the required fine sandstone mud content, a fracturing test is performed on the target rock layer. If the fracturing property of the target rock layer deteriorates, the target horizon is not conducive to fracturing treatment.

[0168] According to the rock formation conditions obtained by logging, the target rock formation of the main control layer is corrected and selected to the nearest rock formation with a sandstone content that meets the fine sandstone content standard or above, in order from near to far from the current target layer.

[0169] In some embodiments, in steps S2 to S4, each level of rock burst main control layer or each level of mine earthquake main control layer may have multiple target layers.

[0170] In some embodiments, in steps S2 to S4, each level of rock burst main control layer or each level of mine earthquake main control layer is treated by fracturing or blasting;

[0171] The mechanical properties of the rock burst main control layer or the mine earthquake main control layer after being controlled are weakened. During the control analysis, it is necessary to analyze the attenuation effect and structural regulation effect of the coordinated rock burst main control layer or the mine earthquake main control layer after being controlled, so as to eliminate the rock burst control layer or the mine earthquake control layer that no longer has rock burst risk or mine earthquake risk.

[0172] In some embodiments, in steps S2 to S4, when there are multiple layers of thick hard roof in the mine, in the process of step-by-step determination and management analysis of the multi-level mine earthquake main control layers or the multi-level rock burst main control layers, the number of layers for fracturing management should be determined based on the position of the disaster-causing rock layer.

[0173] In some embodiments, in order to further accurately determine the mine earthquake disaster-causing layer, the box plot + event scatter normal distribution diagram is used in stages to statistically analyze the vertical distribution patterns of microseismic events of different energy levels to further verify whether the layer determined by the mine earthquake main control layer is correct.

[0174] According to the attached Figures 10-18 The following examples are described.

[0175] In some embodiments, in step S5, determining the layout design of the layered fracturing further includes the following steps:

[0176] Determine the mine geological conditions and fracturing construction parameters, estimate the expansion of the mine fracturing network, collect working face width information and strike length information, analyze the development of lateral mining-induced cracks in the working face, and estimate the construction length of surface vertical wells, underground horizontal wells, surface vertical wells, surface horizontal wells, and multi-layer horizontal wells.

[0177] It is understandable that by collecting mine geological data and analyzing the physical and mechanical properties of coal-bearing strata, we can determine the fracturing operation parameters suitable for the mine, such as fracturing fluid type, fracturing pressure, fracturing flow rate, etc. This provides a scientific basis for subsequent fracturing operations and ensures the safety and effectiveness of the fracturing process.

[0178] Based on the determined construction parameters, numerical simulation and other methods are used to estimate the expansion of the fracture network during the fracturing process, including the length, width, and height of the fractures. This helps to optimize the well layout and improve the fracturing effect.

[0179] like Figure 10 and Figure 11 As shown, in some embodiments, in a working face with a width of less than 350 m, the implementation of the combined well fracturing method of surface vertical wells and downhole horizontal wells includes the following steps:

[0180] According to the estimated fracturing information of the horizontal well and the fracturing range of the vertical well, the horizontal well construction information is determined, and the impact rock pressure control layer is fracturing constructed based on the horizontal well construction information. The underground horizontal well is located between the ground vertical well and the working face tunnel.

[0181] Before arranging wells for fracturing, the following steps are also included: obtaining the width of the working face to be mined and the range of lateral mining cracks of the mined working face; determining the vertical well construction information based on the width of the working face to be mined, the range of lateral mining cracks and the estimated fracturing information of the vertical well; performing fracturing construction on the mine seismic control layer and the rock burst control layer based on the vertical well construction information; and obtaining the vertical well fracturing range of the ground vertical well.

[0182] It is understandable that due to the limited fracturing coverage of the ground vertical well 3, it is easy to form a fracturing blind area at the edge of the vertical well fracturing coverage (i.e., the area close to the tunnels on both sides of the working face 2 to be mined), resulting in insufficient pressure relief in the area close to the tunnels on both sides of the low-level roof of the working face 2 to be mined (i.e., the rock burst control layer), making it difficult to completely eliminate the risk of rock burst on the low-level roof.

[0183] In this embodiment, a ground vertical well 3 is used to pre-crack the rock burst control layer and the mine earthquake control layer of the mining face 2, so that the vertical well fracture network can be extended to the rock burst control layer and the mine earthquake control layer. At the same time, an underground horizontal well 4 is used to pre-crack the rock burst control layer near the tunnel area. In this way, all-round and sufficient fracturing and pressure relief can be achieved at the high, medium and low layers of the thick hard roof of the mining face 2, preventing the occurrence of pressure relief blind spots. It is therefore more suitable for mines where rock burst and mine earthquake disasters coexist, and can achieve coordinated prevention and control of rock burst and mine earthquake disasters.

[0184] Specifically, if Figure 10 As shown, the direction of the working face 2 to be mined is the direction of coal mining advancement, and the working face 2 to be mined is inclined perpendicular to its direction; the tunnel located on the side of the working face 2 to be mined close to the mined working face 1 is the auxiliary transport tunnel 21, and the tunnel located on the side of the working face 2 to be mined away from the mined working face 1 is the rubber transport tunnel 22. The widths of the auxiliary transport tunnel 21 and the rubber transport tunnel 22 are equal, the mined working face 1 and the working face 2 to be mined are parallel and a coal pillar is provided between them, and the auxiliary transport tunnel 21 is closer to the mined working face 1 than the rubber transport tunnel 22.

[0185] The side wall of the auxiliary transport tunnel 21 close to the working face 2 to be mined is its main side, the side wall of the auxiliary transport tunnel 21 away from the working face 2 to be mined is its secondary side, the side wall of the rubber transport tunnel 22 close to the working face 2 to be mined is its main side, and the side wall of the rubber transport tunnel 22 away from the working face 2 to be mined is its secondary side.

[0186] The ground vertical well 3 and the underground horizontal well 4 of the embodiment of the present invention are arranged in the thick hard roof of the working face 2 to be mined of the target mine, and are used to pre-crack and relieve pressure on the thick hard roof to achieve coordinated prevention and control of rock burst and mine earthquake disasters.

[0187] like Figure 11 As shown, the target mine's thick, hard roof consists of multiple rock layers from bottom to top. First, the fracture zone height is calculated based on a combination of theoretical calculations and field measurements. The thick, intact, and strong roof below the fracture zone height range serves as the rock burst control layer, typically no less than 10 meters thick. The thick, intact, and strong roof above the fracture zone height range serves as the mine seismic control layer, typically no less than 30 meters thick. A surface vertical well 3 vertically penetrates both the rock burst control layer and the rock burst control layer. An underground horizontal well 4 is located within the rock burst control layer and extends along the strike of the working face 2 to be mined.

[0188] It is known that the mined working face 1 is a working face that has been mined, and lateral mining cracks will be generated laterally of the mined working face. Optionally, the range of the lateral mining cracks of the mined working face 1 can be estimated based on the angle of rock formation movement, or detected through means such as geophysical exploration, thereby determining the range of the lateral mining cracks of the mined working face.

[0189] Optionally, the fracturing construction steps of the surface vertical well 3 and the underground horizontal well 4 in the embodiment of the present invention are: drilling first and then fracturing, wherein the drilling is carried out by a drilling rig and the fracturing is carried out by a fracturing pump truck.

[0190] In some embodiments, determining the estimated vertical well fracturing information and the estimated horizontal well fracturing information for the target mine based on the acquired fracturing construction information of surrounding mines includes:

[0191] Based on the vertical well fracturing construction information obtained from the surrounding mines, the estimated vertical well fracturing information for the target mine is determined, and based on the horizontal well fracturing construction information obtained from the surrounding mines, the estimated horizontal well fracturing information for the target mine is determined.

[0192] It is understood that the geological conditions of the surrounding mines should be similar to those of the target mine.

[0193] Therefore, based on the vertical well fracturing construction information of surrounding mines with similar geological conditions, the expansion of the vertical well fracturing network of the target mine under the preset fracturing pressure and fracturing flow rate can be estimated to determine the vertical well estimated fracturing information such as the estimated width of the fracturing network and the estimated length of the fracturing network, which makes it easier for construction personnel to determine the construction position, spacing and other parameters of the ground vertical well 3, providing a basis for determining the vertical well construction information, thereby ensuring that the vertical well fracturing range 31 can cover the thick hard roof of the working face 2 to be mined, and reducing the pre-cracking blind area.

[0194] Based on the horizontal well fracturing construction information of surrounding mines with similar geological conditions, the expansion of the horizontal well fracturing network of the target mine under the preset fracturing pressure and fracturing flow rate can be estimated to determine the estimated horizontal well fracturing range 41 and other horizontal well estimated fracturing information, which makes it easier for construction personnel to determine the construction position, spacing and other parameters of the underground horizontal well 4, providing a basis for determining the horizontal well construction information, so that the blind area of ​​the ground vertical well 3 fracturing construction can be further fractured through the underground horizontal well 4 fracturing construction, ensuring the comprehensive unloading of the thick hard roof of the working face 2 to be mined, and realizing the coordinated prevention and control of rock burst and mine tremors.

[0195] In some embodiments, the tunnels located on both sides of the working face 2 to be mined are an auxiliary transport tunnel 21 and a rubber transport tunnel 22. The auxiliary transport tunnel 21 is closer to the mined working face 1 than the rubber transport tunnel 22. The vertical well construction information includes the inclined construction position of the vertical well along the inclination of the working face 2 to be mined. The arrangement of the inclined construction position of the vertical well is as follows:

[0196] If the lateral mining cracks do not extend to the thick hard roof of the working face 2 to be mined, the distance between the shaft of the ground vertical well 3 and the positive wall of the auxiliary transport roadway 21 is equal to half the width of the working face to be mined (e.g. Figure 10 shown);

[0197] If the lateral mining fracture range extends to the thick hard roof of the working face 2 to be mined, the distance between the well axis of the ground vertical well 3 and the front side of the auxiliary transport tunnel 21 is greater than half the width of the working face to be mined, so that the vertical well fracturing range 31 and the lateral mining fracture range are arranged at intervals.

[0198] It is known that if the vertical well fracturing range 31 intersects with the lateral mining fracture range, it will cause leakage, making the vertical well fracturing effect of the surface vertical well 3 worse.

[0199] If the mining cracks do not extend to the thick hard roof of the working face 2 to be mined, the ground vertical well 3 can be arranged in the middle position of the working face 2 to be mined along the inclination of the working face 2 to be mined, that is, the distance between the well axis of the ground vertical well 3 and the positive side of the auxiliary transport tunnel 21 is equal to half of the width of the working face to be mined. Therefore, when conducting fracturing construction of the ground vertical well 3, it can be fractured evenly from the middle area of ​​the working face 2 to both sides, so that the vertical well fracturing range 31 can completely cover the thick hard roof at the top of the working face 2 to be mined in the inclination direction, thereby improving the fracturing effect.

[0200] If the mining cracks extend to the thick hard roof of the working face 2 to be mined, it is necessary to move the ground vertical well 3 at the inclined position in the direction away from the auxiliary transport tunnel 21 according to the boundary position of the lateral mining crack range, that is, the distance between the well axis of the ground vertical well 3 and the positive side of the auxiliary transport tunnel 21 is greater than half of the width of the working face to be mined, so that the vertical well fracturing range 31 formed by the fracturing construction of the ground vertical well 3 is arranged at intervals from the lateral mining crack range (the two do not affect each other), thereby ensuring the fracturing effect of the ground vertical well 3.

[0201] Therefore, the thick hard roof of the working face 2 to be mined can be pre-cracked by the fracturing construction of the ground vertical well 3 to achieve a better anti-blowout effect.

[0202] It can be understood that the main side of the auxiliary transport lane 21 and the main side of the rubber transport lane 22 form the above-mentioned lane main side.

[0203] In some embodiments, as Figure 10 and Figure 11 As shown, the vertical well construction information also includes the vertical well construction positions along the direction of the working face 2 to be mined. The arrangement of the vertical well construction positions is as follows: there are multiple ground vertical wells 3, and the multiple ground vertical wells 3 are arranged along the direction of the working face.

[0204] In some embodiments, the estimated fracturing information of the vertical well includes the estimated width of the fracture network. The distance between two adjacent ground vertical wells 3, the estimated width of the fracture network, and the periodic fracturing step distance of the thick hard roof of the working face 2 to be mined satisfy the following formula:

[0205] D=(b+d) / 2

[0206] D is the distance between two adjacent ground vertical wells 3, b is the estimated width of the fracture network, and d is the periodic fracture step distance of the thick hard roof of the working face 2 to be mined.

[0207] Through the above settings, it can be ensured that the fracture networks of two adjacent ground vertical wells 3 are connected, so that the fracture networks of multiple ground vertical wells 3 can completely cover the thick hard roof of the working face 2 to be mined along the direction of the working face 2 to be mined, thereby achieving a better pre-cracking effect.

[0208] Optionally, the periodic breaking step distance of the thick hard roof of the working face 2 to be mined is obtained according to the limit breaking step distance formula.

[0209] like Figure 10 As shown, the estimated width b of the hydraulic fracturing network is the dimension of the hydraulic fracturing network along the direction of the working face 2 to be mined; the estimated length L of the hydraulic fracturing network is the dimension of the hydraulic fracturing network along the inclination of the working face 2 to be mined.

[0210] In some embodiments, obtaining the vertical well fracture range 31 includes:

[0211] The fracture network expansion of the surface vertical well 3 is monitored by surface microseismic monitoring to obtain the vertical well fracturing range 31.

[0212] After the fracturing construction of the ground vertical well 3 is completed, the ground microseismic monitoring method is used to obtain and determine the vertical well fracturing range 31, and then determine the fracturing blind area of ​​the ground vertical well 3, providing more accurate data support for the fracturing construction of the underground horizontal well 4.

[0213] In some embodiments, the underground horizontal wells 4 are arranged in pairs, and the two underground horizontal wells 4 arranged in pairs are respectively arranged close to the auxiliary transport tunnel 21 and the rubber transport tunnel 22.

[0214] After the fracturing construction of the ground vertical well 3 is completed, the vertical well fracturing network expands along the inclination of the working face 2 to be mined, and the vertical well fracturing network extends to the auxiliary transport tunnel 21 and the rubber transport tunnel 22 along the two edges of the inclination of the working face 2 to be mined. Fracturing blind spots are easily formed in the low-level roofs in the top areas of the auxiliary transport tunnel 21 and the rubber transport tunnel 22; by setting up two underground horizontal wells 4, the low-level thick and hard roofs in the top areas of the auxiliary transport tunnel 21 and the rubber transport tunnel 22 can be further fractured at the same time, reducing fracturing blind spots and ensuring anti-bumping effects.

[0215] Optionally, the length of the underground horizontal well 4 is 500m to 800m.

[0216] When the strike length of the working face 2 to be mined is greater than the length of the underground horizontal well 4, multiple underground horizontal wells 4 can be set along the strike length of the working face 2 to be mined, so that the horizontal well fracturing network can completely cover the strike length of the working face 2 to be mined, preventing the occurrence of fracturing blind spots.

[0217] In some embodiments, as Figure 10 As shown, the estimated fracturing information of the horizontal well includes an estimated fracturing range 41 of the horizontal well. The estimated fracturing range 41 of the horizontal well arranged near the auxiliary transportation roadway 21 has a first boundary 411 and a second boundary 412 arranged along the inclination of the working face 2 to be mined. The first boundary 411 is arranged on the side of the auxiliary transportation roadway 21 close to the working face 2 to be mined, and the second boundary 412 is arranged on the side of the auxiliary transportation roadway 21 away from the working face 2 to be mined. The distance D1 between the first boundary 411 and the main side of the auxiliary transportation roadway 21 is six times the width of the auxiliary transportation roadway 21, and the distance D2 between the second boundary 412 and the secondary side of the auxiliary transportation roadway 21 is twice the width of the auxiliary transportation roadway 21.

[0218] The estimated fracturing range 41 of the horizontal well arranged near the rubber transport tunnel 22 has a third boundary 413 and a fourth boundary 414 arranged along the inclination of the working face 2 to be mined. The third boundary 413 is arranged on the side of the rubber transport tunnel 22 close to the working face 2 to be mined, and the fourth boundary 414 is arranged on the side of the rubber transport tunnel 22 away from the working face 2 to be mined. The distance D3 between the third boundary 413 and the main side of the rubber transport tunnel 22 is six times the width of the rubber transport tunnel 22, and the distance D4 between the fourth boundary 414 and the secondary side of the rubber transport tunnel 22 is equal to the width of the rubber transport tunnel 22.

[0219] The tunnel is the key area for the prevention and control of rock burst. According to the distribution range of the tunnel surrounding rock stress concentration area and the tunnel roof cutting and unloading requirements, the prevention and control areas (i.e., pre-cracking areas) of the auxiliary transport tunnel 21 main wall, auxiliary transport tunnel 21 secondary wall, rubber transport tunnel 22 main wall and rubber transport tunnel 22 secondary wall can be determined; in addition, since the auxiliary transport tunnel 21 is an air-facing tunnel, it is affected by the lateral hanging roof of the mined working face 1, and the degree of stress concentration of the surrounding rock of the auxiliary transport tunnel 21 is greater than that of the rubber transport tunnel 22. Therefore, the prevention and control area of ​​the secondary wall of the auxiliary transport tunnel 21 is larger than that of the secondary wall of the rubber transport tunnel 22.

[0220] By making the above restrictions on the estimated fracturing range 41 of the horizontal well, the prevention and control area requirements of the auxiliary transport tunnel 21 main side, auxiliary transport tunnel 21 secondary side, rubber transport tunnel 22 main side and rubber transport tunnel 22 secondary side can be met, thereby fully pre-cracking the low-lying thick and hard roof near the tunnel area to ensure the anti-bumping effect.

[0221] Optionally, if a single horizontal well cannot cover the above-mentioned area through fracturing, the number of underground horizontal wells can be increased. In other words, multiple underground horizontal wells can be set at the top of the auxiliary transport tunnel 21 or the rubber transport tunnel 22 along the inclination of the working face to be mined, and the well axes of the multiple underground horizontal wells can be arranged in parallel to ensure that the fracturing network of the underground horizontal wells can completely cover the above-mentioned prevention and control area.

[0222] In some embodiments, the vertical well construction information includes the number of vertical well fracturing points 32, which are grouped in two. There are multiple groups of vertical well fracturing points 32, and the multiple groups of vertical well fracturing points 32 are arranged in sequence along the extension direction of the ground vertical well 3; the horizontal well construction information includes the number of horizontal well fracturing points 42, which are multiple. There are multiple horizontal well fracturing points 42, which are grouped in two. There are multiple groups of horizontal well fracturing points 42, and the multiple groups of horizontal well fracturing points 42 are arranged in sequence along the extension direction of the horizontal well.

[0223] Specifically, if Figure 11As shown, during the fracturing operation of a surface vertical well 3, a perforation process is first used to form a set of vertical well fracturing points 32 targeting the lowest rock formation. A vertical fracturing segment is formed between the two vertical well fracturing points 32 in this set. Water injection fracturing is then performed on these two vertical well fracturing points 32. A bridge plugging process is then used to seal the vertical fracturing segment, completing the vertical well fracturing of the lowest rock formation. The same method is then used to perform vertical well fracturing on multiple rock formations in the rock burst control layer and the mine seismic control layer, starting from the bottom up.

[0224] Similarly, when performing fracturing construction of the underground horizontal well 4, a group of horizontal well fracturing points 42 away from the wellhead is first formed, and a horizontal fracturing section is formed between the two horizontal well fracturing points 42 of this group. Water injection fracturing is performed on the two horizontal well fracturing points 42 of this group, and then the horizontal fracturing section is sealed using a bridge plugging process, thus completing the fracturing construction of this section of the horizontal well; thereafter, the same construction method is used to construct multiple horizontal fracturing sections in sequence along the direction close to the wellhead, thereby realizing fracturing construction of the rock burst control layer, reducing fracturing blind spots, and reducing the risk of rock burst on the low-lying roof.

[0225] Optionally, the distance between two vertical well fracturing points 32 in the same group is 18 m to 25 m, preferably 20 m.

[0226] Optionally, the distance between two horizontal well fracturing points 42 in the same group of horizontal well fracturing points is 18 m to 25 m, preferably 20 m.

[0227] According to the attached Figure 12 and Figure 13 The following examples are described.

[0228] In some embodiments, in a working face with a width greater than or equal to 350 m, the implementation of the combined well fracturing method of surface vertical wells and downhole horizontal wells includes the following steps:

[0229] The horizontal well construction information is determined according to the estimated fracturing information of the horizontal well and the fracturing range of the vertical well, and the rock burst control layer is subjected to fracturing construction based on the horizontal well construction information. The downhole horizontal well is arranged between the ground vertical well and the tunnel of the working face; wherein, the vertical well construction information includes the number of the ground vertical wells, and the number of the ground vertical wells is multiple, and the multiple ground vertical wells are divided into at least two vertical well groups, and at least two of the vertical well groups are arranged at intervals along the inclination of the working face to be mined.

[0230] Before arranging the wells for fracturing, the following steps are also included: obtaining the width of the working face to be mined and the range of lateral mining cracks of the mined working face 1, determining the vertical shaft construction information based on the width of the working face to be mined, the range of lateral mining cracks and the estimated fracturing information of the vertical shaft, performing fracturing construction on the impact ground pressure control layer and the mine earthquake control layer based on the vertical shaft construction information, and obtaining the vertical well fracturing range 31 of the ground vertical well 3.

[0231] It is understandable that due to the limited fracturing coverage of the ground vertical well 3, it is easy to form a fracturing blind area at the edge of the vertical well fracturing coverage (i.e., the area close to the tunnels on both sides of the working face 2 to be mined), resulting in insufficient pressure relief in the area close to the tunnels on both sides of the low-level roof of the working face 2 to be mined (i.e., the main controlling rock formation of the impact), making it difficult to completely eliminate the risk of impact ground pressure on the low-level roof.

[0232] In this embodiment, a ground vertical well 3 is used in the middle of the working face 2 to be mined to perform pre-cracking treatment on its impact main controlling rock layer and the mine earthquake main controlling rock layer, and at least two vertical well groups are arranged at intervals along the inclination of the working face 2 to be mined, which can increase the coverage of the fracture network of the ground vertical well 3 on the inclination of the working face 2 to be mined, and is more suitable for pre-cracking and pressure relief of ultra-long working faces (face width greater than or equal to 350m); at the same time, an underground horizontal well 4 is used to perform pre-cracking treatment in the key anti-impact area of ​​the thick hard roof of the working face 2 to be mined close to the tunnels on both sides, so that the horizontal well pressure fracture network expands in the impact main controlling rock layer; thus, the combined well layout method of the ground vertical well 3 and the underground horizontal well 4 can achieve all-round and sufficient pre-cracking of the thick hard roof of the ultra-long working face, reduce the fracturing blind area, and realize the coordinated prevention and control of impact ground pressure and mine earthquake disasters.

[0233] Specifically, if Figure 12 and Figure 13 As shown, the target mine includes multiple extra-long working faces with a width greater than or equal to 350 meters. The mined extra-long working face is referred to as the mined working face 1, and the unmined extra-long working face is referred to as the unmined working face 2. A coal pillar exists between unmined working face 2 and mined working face 1. The strike of unmined working face 2 is the direction of coal mining advancement, and the inclination of unmined working face 2 is perpendicular to its strike. The combined well layout method of this embodiment of the present invention is suitable for pre-cracking the thick hard roof of unmined working face 2, reducing the risk of rock burst and mine tremors during mining of unmined working face 2.

[0234] The tunnel located on the side of the working face 2 to be mined close to the mined working face 1 is the auxiliary transport tunnel 21, and the tunnel located on the side of the working face 2 to be mined away from the mined working face 1 is the rubber transport tunnel 22. The widths of the auxiliary transport tunnel 21 and the rubber transport tunnel 22 are equal; the side of the auxiliary transport tunnel 21 close to the working face 2 to be mined is its main side, and the side of the auxiliary transport tunnel 21 away from the working face 2 to be mined is its secondary side, the side of the rubber transport tunnel 22 close to the working face 2 to be mined is its main side, and the side of the rubber transport tunnel 22 away from the working face 2 to be mined is its secondary side.

[0235] like Figure 12 and Figure 13As shown, the thick, hard roof consists of multiple rock layers from bottom to top. First, the fracture zone height is determined based on a combination of theoretical calculations and field measurements. The thick, intact, and strong roof below the fracture zone height range is the primary percussion-controlled rock layer, typically no less than 10 meters thick. The thick, intact, and strong roof above the fracture zone height range is the primary mine-seismic-controlled rock layer, typically no less than 30 meters thick. A surface vertical well 3 penetrates the primary mine-seismic-controlled rock layer and the primary percussion-controlled rock layer. An underground horizontal well 4 is located in the primary percussion-controlled rock layer and extends along the strike of the working face 2 to be mined.

[0236] Optionally, based on the vertical shaft fracturing construction information obtained from the surrounding mines, the estimated vertical shaft fracturing information for the target mine is determined, and based on the horizontal well fracturing construction information obtained from the surrounding mines, the estimated horizontal well fracturing information for the target mine is determined.

[0237] It is understood that the geological conditions of the surrounding mines are similar to those of the target mine.

[0238] Based on the vertical shaft fracturing construction information of surrounding mines with similar geological conditions, the expansion of the vertical shaft fracturing network of the target mine under the preset fracturing pressure and preset fracturing flow rate can be estimated, and the estimated vertical shaft fracturing information such as the estimated width and length of the fracturing network can be determined; thereby facilitating the construction personnel to determine the construction position, construction spacing and other parameters of the ground vertical well 3, providing a basis for determining the vertical shaft construction information, thereby ensuring that the vertical well fracturing range 31 can cover a large area of ​​the thick hard roof of the working face 2 to be mined, thereby improving the pre-cracking effect.

[0239] At the same time, based on the horizontal well fracturing construction information of the surrounding mines, the expansion of the fracture network of the underground horizontal well 4 of the target mine under the preset fracturing pressure and preset fracturing flow rate can be estimated, and the estimated fracturing range of the horizontal reinforcement and other horizontal well estimated fracturing information can be determined, which makes it easier for construction personnel to determine the construction position, spacing and other parameters of the underground horizontal well 4, providing a basis for determining the horizontal well construction information, and thus using the underground horizontal well 4 fracturing construction to pre-crack the key anti-blowout areas on the top of the tunnels on both sides, reducing fracturing blind spots.

[0240] It is known that the mined working face 1 is a working face that has been mined, and lateral mining cracks will be generated laterally of the mined working face. Optionally, in step S2, the range of the lateral mining cracks of the mined working face 1 can be estimated based on the angle of rock formation movement, or detected through means such as geophysical exploration, thereby determining the range of the lateral mining cracks of the mined working face.

[0241] Optionally, ground microseismic monitoring is used to monitor the expansion of the ground vertical well 3 fracture network, and then determine the vertical well fracturing range 31, providing a basis for the horizontal well construction information in step S3, and fully ensuring the fracturing pressure relief effect.

[0242] Optionally, the fracturing construction steps of the ground vertical well 3 and the underground horizontal well 4 are: first use a drilling rig to perform drilling construction, and then use a fracturing pump truck to perform fracturing construction; wherein, the ground vertical well 3 is constructed from the surface downward to form a ground vertical well 3, and the underground horizontal well 4 is constructed obliquely upward from the rubber transport tunnel 22 and the auxiliary transport tunnel 21 to form an underground horizontal well 4.

[0243] Alternatively, as Figure 12 and Figure 13 As shown, during the fracturing construction of the ground vertical well 3, a perforation process is first used to form two vertical well fracturing points 35 in the lowest rock formation. The two vertical well fracturing points 35 form a group, and the spacing between the two vertical well fracturing points 35 in the same group is 18m to 25m, preferably 20m. A vertical well fracturing section is formed between the two vertical well fracturing points 35 in the same group. Water injection fracturing is performed on the two vertical well fracturing points 35 in this group. After that, a bridge plugging process is used to plug the vertical well fracturing section, thus completing the vertical well fracturing construction for the lowest rock formation. Subsequently, the same method is used to perform vertical well fracturing on multiple rock formations from bottom to top, so that the vertical well fracturing network can be distributed in the rock formation mainly controlled by impact and the rock formation mainly controlled by mine earthquakes.

[0244] When performing fracturing construction of the underground horizontal well 4, a perforation process is first used to form two horizontal well fracturing points 42 at one end of the underground horizontal well 4 away from its wellhead. The two horizontal well fracturing points 42 form a group, and the distance between the two horizontal well fracturing points 42 in the same group is 18m to 25m, preferably 20m; a horizontal well fracturing section is formed between the two horizontal well fracturing points 42 in the same group, and water injection fracturing is performed on the horizontal fracturing points 61 of this group. Then, a bridge plugging process is used to seal the horizontal fracturing section, thus completing the fracturing construction of the horizontal well in this section; thereafter, the same construction method is used to construct multiple horizontal fracturing sections in sequence along the direction close to the wellhead, thereby realizing fracturing construction on the impact main control rock formation, reducing fracturing blind areas, and reducing the risk of impact ground pressure on the low-lying roof.

[0245] In some embodiments, as Figure 12 and Figure 13 As shown, the two adjacent vertical shaft groups are respectively the first vertical shaft group 33 and the second vertical shaft group 34. The first vertical shaft group 33 includes a plurality of first vertical shafts 33 arranged at intervals along the direction of the working face 2 to be mined, and the second vertical shaft group 34 includes a plurality of second vertical shafts 34 arranged at intervals along the direction of the working face 2 to be mined. The vertical plane parallel to the direction of the working face 2 to be mined is defined as a reference plane, and the projections of the plurality of first vertical shafts 33 on the reference plane and the projections of the plurality of second vertical shafts 34 on the reference plane are arranged alternately in sequence.

[0246] Through the above arrangement, the multiple first vertical shafts 33 of the first vertical shaft 33 group and the multiple second vertical shafts 34 of the second vertical shaft 34 group are staggered with each other in a three-flower shape. The fracturing network formed by the first vertical shaft 33 and the fracturing network formed by the second vertical shaft 34 are staggered with each other, which can reduce the number of ground vertical wells 3 while ensuring the coverage of the fracturing network at the top of the working face 2 to be mined. In other words, it can reduce construction costs while ensuring the pre-cracking effect.

[0247] It can be understood that the reference surface is vertically arranged and parallel to the direction of the working surface 2 to be mined.

[0248] Optionally, based on the vertical shaft construction information, the thick hard roof of the working face 2 to be mined is subjected to fracturing construction to form a ground vertical well 3; when constructing two vertical shaft groups, an interval alternating construction method is adopted.

[0249] In some embodiments, as Figure 12 and Figure 13 As shown, the distance between two adjacent first vertical shafts 33 is equal to the distance between two adjacent second vertical shafts 34.

[0250] In some embodiments, as Figure 12 and Figure 13 As shown, the projections of the plurality of first vertical shafts 33 and the plurality of second vertical shafts 34 on the reference plane form a plurality of projection areas, and the plurality of projection areas are evenly arranged along the direction of the working face 2 to be mined.

[0251] Specifically, the projection of the first vertical shaft 33 on the vertical plane forms a first projection area, and the projection of the second vertical shaft 34 on the vertical plane forms a second projection area. Multiple first projection areas and multiple second projection areas are arranged alternately along the direction of the working face 2 to be mined, and the spacing between the first projection area and two adjacent second projection areas is equal. In other words, the line connecting the first vertical shaft 33 and the two adjacent second vertical shafts 34 forms an isosceles triangle. This further improves the uniformity of the distribution of the first vertical shaft 33 and the second vertical shaft 34 at the top of the working face 2 to be mined, thereby improving the uniformity of the distribution of the hydraulic fracturing network, enhancing the pre-fracture effect, and ensuring the prevention and control of rock burst and mine earthquake disasters.

[0252] In some embodiments, the estimated fracturing information of the vertical well includes the estimated width of the fracture network. The distance between two adjacent ground vertical wells 3, the estimated width of the fracture network, and the periodic fracture step distance of the thick hard roof of the working face 2 to be mined satisfy the following formula:

[0253] D=b+d

[0254] D is the distance between two adjacent ground vertical wells 3, b is the estimated width of the fracture network, and d is the periodic fracture step distance of the thick hard roof of the working face 2 to be mined.

[0255] Through the above arrangement, it can be ensured that the multiple staggered first vertical shafts 33 and second vertical shafts 34 fully cover the thick hard roof of the working face 2 to be mined along the direction of the working face 2 to be mined, thereby achieving a better pre-cracking effect.

[0256] Optionally, the periodic breaking step distance of the thick hard roof of the working face 2 to be mined is obtained according to the limit breaking step distance formula.

[0257] like Figure 12 and Figure 13 As shown, the estimated width b of the fracture network of the ground vertical well 3 is the dimension of the fracture network of the ground vertical well 3 along the direction of the working face 2 to be mined, and the estimated length L of the fracture network is the dimension of the fracture network of the ground vertical well 3 along the inclination of the working face 2 to be mined.

[0258] In some embodiments, the number of vertical shaft groups is two.

[0259] In this embodiment of the present invention, by staggering the two vertical shaft groups, it is possible to ensure that the fracturing network of the surface vertical shaft 3 fully covers the thick, hard roof of the working face 2 to be mined. In other embodiments, when the width of the extra-long working face reaches a certain value, more than two vertical shaft groups may be provided to ensure that the fracturing network of the surface vertical shaft 3 fully covers the thick, hard roof of the working face 2 to be mined.

[0260] In some embodiments, the tunnels located on both sides of the working face 2 to be mined are the auxiliary transport tunnel 21 and the rubber transport tunnel 22. The auxiliary transport tunnel 21 is closer to the mined working face 1 than the rubber transport tunnel 22. The first vertical shaft 33 is closer to the auxiliary transport tunnel 21 than the second vertical shaft 34. The vertical shaft construction information also includes the vertical shaft inclination position in the direction of the working face 2 to be mined. The arrangement of the vertical shaft inclination position is as follows:

[0261] If the lateral mining cracks do not extend to the thick hard roof of the working face 2 to be mined, the distance between the shaft of the first vertical shaft 33 and the front wall of the auxiliary transport roadway 21 is equal to one-third of the width of the working face to be mined, and the distance between the shaft of the second vertical shaft 34 and the front wall of the rubber transport roadway 22 is equal to one-third of the width of the working face to be mined;

[0262] If the lateral mining fracture range extends to the thick hard roof of the working face 2 to be mined, the distance between the shaft of the first vertical shaft 33 and the front side of the auxiliary transport tunnel 21 is greater than one-third of the width of the working face to be mined, so that the vertical well fracturing range 31 and the mining fracture range are arranged at intervals.

[0263] It is known that if the vertical well fracturing range 31 intersects with the mining fracture range, it will cause leakage, making the fracturing effect of the ground vertical well 3 worse.

[0264] If the lateral mining cracks do not extend to the top of the working face 2 to be mined, the first vertical shaft 33 group and the second vertical shaft 34 group divide the working face 2 to be mined into three equal parts along the inclination thereof, that is, the distance between the shaft of the first vertical shaft 33 and the main wall of the auxiliary transport roadway 21 is equal to one-third of the width of the working face to be mined, and the distance between the shaft of the second vertical shaft 34 and the main wall of the rubber transport roadway 22 is equal to one-third of the width of the working face to be mined (e.g. Figure 12 and Figure 13 Thus, it can be ensured that the fracture network of the ground vertical well 3 can cover the thick hard roof of the working face 2 to be mined in all directions, thereby improving the fracturing effect.

[0265] If the range of the lateral mining cracks extends to the top of the working face 2 to be mined, the first vertical shaft 33 group and the second vertical shaft 34 group need to be moved away from the mined working face 1, that is, the distance between the well axis of the first vertical shaft 33 and the front side of the auxiliary transport tunnel 21 is greater than one-third of the width of the working face to be mined; thereby, the vertical well fracturing range 31 formed by the fracturing construction of the ground vertical well 3 has a certain gap with the lateral mining crack range, thereby ensuring the fracturing effect of the ground vertical well 3.

[0266] In some embodiments, as Figure 12 and Figure 13 As shown, the underground horizontal wells 4 are arranged in pairs, and the two underground horizontal wells 4 arranged in pairs are respectively arranged close to the auxiliary transport tunnel 21 and the rubber transport tunnel 22.

[0267] By setting up two underground horizontal wells 4, the key prevention and control areas at the top of the auxiliary transport tunnel 21 and the rubber transport tunnel 22 can be fractured at the same time to prevent the occurrence of fracturing blind areas and ensure the anti-bumping effect.

[0268] Optionally, the length of the downhole horizontal well 4 is 500m to 800m. When the strike length of the working face 2 to be mined is greater than the length of the downhole horizontal well 4, multiple downhole horizontal wells 4 can be set along the strike length of the working face 2 to be mined, ensuring that the fracturing network of the downhole horizontal wells 4 can fully cover the extension direction of the auxiliary transport roadway 21 and the rubber transport roadway 22, thereby achieving all-round pre-cracking of the key prevention and control area at the top of the roadway.

[0269] In some embodiments, as Figure 12 and Figure 13 As shown, the estimated fracturing information of the horizontal well includes an estimated fracturing range 41 of the horizontal well. The estimated fracturing range 41 of the horizontal well arranged near the auxiliary transportation roadway 21 has a first boundary 411 and a second boundary 412 arranged along the inclination of the working face 2 to be mined. The first boundary 411 is arranged on the side of the auxiliary transportation roadway 21 close to the working face 2 to be mined, and the second boundary 412 is arranged on the side of the auxiliary transportation roadway 21 away from the working face 2 to be mined. The distance D1 between the first boundary 411 and the main side of the auxiliary transportation roadway 21 is six times the width of the auxiliary transportation roadway 21, and the distance D2 between the second boundary 412 and the secondary side of the auxiliary transportation roadway 21 is twice the width of the auxiliary transportation roadway 21.

[0270] The estimated fracturing range 41 of the horizontal well arranged near the rubber transport tunnel 22 has a third boundary 413 and a fourth boundary 414 arranged along the inclination of the working face 2 to be mined. The third boundary 413 is arranged on the side of the rubber transport tunnel 22 close to the working face 2 to be mined, and the fourth boundary 414 is arranged on the side of the rubber transport tunnel 22 away from the working face 2 to be mined. The distance D3 between the third boundary 413 and the main side of the rubber transport tunnel 22 is six times the width of the rubber transport tunnel 22, and the distance D4 between the fourth boundary 414 and the secondary side of the rubber transport tunnel 22 is equal to the width of the rubber transport tunnel 22.

[0271] Since the top area of ​​the tunnel is the key prevention and control area for rock burst, the prevention and control areas (i.e., pre-cracking areas) of the main side of the auxiliary tunnel 21, the secondary side of the auxiliary tunnel 21, the main side of the rubber tunnel 22, and the secondary side of the rubber tunnel 22 can be determined according to the distribution range of the tunnel surrounding rock stress concentration area and the tunnel roof cutting and unloading requirements; in addition, since the auxiliary tunnel 21 is an air-facing tunnel, it is affected by the lateral hanging roof of the mined working face 1, and the degree of stress concentration of the surrounding rock of the auxiliary tunnel 21 is greater than that of the rubber tunnel 22. Therefore, the prevention and control area of ​​the secondary side of the auxiliary tunnel 21 is larger than that of the secondary side of the rubber tunnel 22.

[0272] By imposing the above restrictions on the range of horizontal well fracturing, the prevention and control area requirements of the auxiliary transport tunnel 21 main wall, auxiliary transport tunnel 21 secondary wall, rubber transport tunnel 22 main wall and rubber transport tunnel 22 secondary wall can be met, thereby fully pre-cracking the low-lying thick and hard roof near the tunnel area and reducing the risk of impact ground pressure and mine earthquake disasters.

[0273] Optionally, if a single horizontal well cannot cover the above-mentioned area by fracturing, the number of downhole horizontal wells 4 can be increased. In other words, multiple downhole horizontal wells 4 at the top of the auxiliary transport tunnel 21 or the rubber transport tunnel 22 can be set along the inclination of the working face 2 to be mined, and the well axes of the multiple downhole horizontal wells 4 are arranged in parallel.

[0274] According to the attached Figure 14 and Figure 15 The following examples are described.

[0275] In some embodiments, the implementation of the multi-layer horizontal well fracturing method further includes the following steps:

[0276] A first well group and a second well group are arranged at intervals in the inclination direction of the working face, the first well group includes a first low-level horizontal well and a first high-level horizontal well arranged at intervals in the direction of the coal seam height, the second well group includes a second low-level horizontal well and a second high-level horizontal well arranged at intervals in the direction of the coal seam height, the extension direction of the fracture range formed by the fracturing of the first low-level horizontal well coincides with the extension direction of the fracture range formed by the fracturing of the second low-level horizontal well, the extension direction of the fracture range formed by the fracturing of the first high-level horizontal well coincides with the extension direction of the fracture range formed by the fracturing of the second high-level horizontal well, and the fracture range formed by the fracturing of the first low-level horizontal well is located below the fracture range formed by the fracturing of the first high-level horizontal well.

[0277] It is understandable that, according to the geological conditions of the mine and the fracturing construction parameters, the first well group 5 and the second well group 6 are arranged at intervals in the inclination direction of the working face 2 to be mined. Among them, the first well group 5 includes a first low-level horizontal well 51 and a first high-level horizontal well 52, and the second well group 6 includes a second low-level horizontal well 61 and a second high-level horizontal well 62. And the extension direction of the fracture range formed by the fracturing of the first low-level horizontal well 51 and the second low-level horizontal well 61 is made to overlap, and the extension direction of the fracture range formed by the fracturing of the first high-level horizontal well 52 and the second high-level horizontal well 62 is made to overlap. The overlap in the extension direction of the fracture range helps to form a continuous fracture network and improve the fracturing effect. By arranging multiple well groups, comprehensive coverage of the fracturing range is achieved, effectively reducing the risk of rock burst and mine tremors.

[0278] In the height direction of the coal seam, the first well group 5 and the second well group 6 are respectively arranged with low-level horizontal wells and high-level horizontal wells at intervals to ensure the reasonable distribution of the fracture range.

[0279] Therefore, in this embodiment, full coverage of the fracturing range is achieved, effectively reducing the risks of rock burst and mine tremors.

[0280] In some embodiments, determining the geological conditions of the mine includes: determining the rock burst layer and the mine earthquake disaster-causing rock layer to facilitate the arrangement of corresponding fracturing wells.

[0281] It is understandable that, because rock burst and mine-induced strata occur at different depths, horizontal wells can be deployed in both these zones to create dual-layer fracturing zones, improving fracturing coverage. Preferably, the wellbore of the horizontal well should be located in the middle of a single sandstone layer or sandstone formation.

[0282] In addition, when there are more than two layers of mine earthquake disaster-causing layers, ground vertical wells are used for fracturing to form multi-layer fracturing layers.

[0283] In some embodiments, determining the mine geological conditions and fracturing construction parameters includes: collecting the geological conditions and fracturing construction parameters of the pre-construction mine or the geological conditions and fracturing construction fracture network expansion similar to the pre-construction mine for comparison according to the corresponding geological conditions and construction parameters.

[0284] It's understandable that a detailed geological survey of the mine where fracking is planned should be conducted, collecting relevant geological data such as coal seam roof thickness and lithology. Also, records of past fracking operations should be collected, including technical parameters such as fracking fluid type, fracking pressure, and fracking flow rate. This collected data allows for a more accurate understanding of the mine's geological conditions and the actual fracking operations, providing a direct basis for subsequent operations.

[0285] If the current mine's geological conditions are similar to those of other known mines, it's possible to collect data on hydraulic fracturing operations in these similar mines, including the expansion of the fracture network during the fracturing process, such as the direction, length, and width of the fractures. By comparing and analyzing the fracturing results of similar mines, we can provide reference and guidance for the current mine, predict the potential expansion of the fracture network, and thus optimize the construction plan.

[0286] Specifically, the geological conditions and fracturing parameters collected from the pre-treatment wells are compared with data from similar mines to identify commonalities and differences, and to assess the impact of these parameters on fracturing effectiveness. This comparative analysis helps identify potential risk factors, providing a basis for adjusting and optimizing operation parameters to ensure the safety and effectiveness of the operation.

[0287] In some embodiments, the first low-level horizontal well 51 and the second low-level horizontal well 61 are arranged at intervals along the dip direction of the working face 2 to be mined, and the first high-level horizontal well 52 and the second high-level horizontal well 62 are arranged at intervals along the dip direction of the working face 2 to be mined.

[0288] It is understandable that if Figure 14 and Figure 15 As shown, the first low-level horizontal well 51 and the second low-level horizontal well 61 are spaced apart in the direction of the working face 2 to be mined, and the first high-level horizontal well 52 and the second high-level horizontal well 62 are spaced apart in the direction of the working face 2 to be mined. This minimizes the risk of fracturing blind spots and avoids stress concentration caused by insufficient fracturing, which can lead to increased impact risk. Furthermore, this allows for intensive management of the surface site and reduces construction costs.

[0289] In some embodiments, the horizontal section of the first low-level horizontal well 51 extends in a direction from the vertical section of the first low-level horizontal well 51 to the vertical section of the second low-level horizontal well 61, the horizontal section of the second low-level horizontal well 61 extends in a direction from the vertical section of the second low-level horizontal well 61 to the vertical section of the first low-level horizontal well 51, the horizontal section of the first high-level horizontal well 52 extends in a direction from the vertical section of the first high-level horizontal well 52 to the vertical section of the second high-level horizontal well 62, and the horizontal section of the second high-level horizontal well 62 extends in a direction from the vertical section of the second high-level horizontal well 62 to the vertical section of the first high-level horizontal well 52.

[0290] It is understandable that if Figure 14 and Figure 15 As shown, the first well group 5 and the second well group 6 are arranged in a split manner, that is, the vertical section of the first well group 5 and the vertical section of the second well group 6 are arranged at intervals in the strike of the working face 2 to be mined, and the horizontal section of the first well group 5 and the horizontal section of the second well group 6 are arranged crosswise with each other, that is, the horizontal section of the first low-level horizontal well 51 and the horizontal section of the second low-level horizontal well 61 are arranged crosswise in the horizontal direction; the horizontal section of the first high-level horizontal well 52 and the horizontal section of the second high-level horizontal well 62 are arranged crosswise in the horizontal direction.

[0291] In other words, the design of opposing extensions helps to form a cross-fracture network between the two horizontal wells, further increasing the coverage of the fracturing. Furthermore, through opposing extensions, a more uniform fracture network can be formed in the thick hard roof of the coal seam, thereby improving the fracturing effect.

[0292] In some embodiments, in a well group, high-level and low-level horizontal wells are constructed simultaneously.

[0293] Understandably, during simultaneous construction, the construction steps of both the high-level and low-level wells need to be coordinated to ensure smooth and safe construction. This coordinated construction can reduce potential conflicts and disruptions during construction, ensuring quality.

[0294] In some embodiments, the method for deploying multiple horizontal wells on the ground according to an embodiment of the present invention further includes the following steps:

[0295] The positions of the horizontal sections of the low-level horizontal well group and the high-level horizontal well group are determined based on the width of the working face 2 to be mined and the development of mining-induced fractures. When there is the influence of mining-induced fractures, the fracturing boundary of the horizontal section is located outside the influence range of the mining-induced fractures; when there is no influence of mining-induced fractures, the position of the horizontal well is roughly half the width of the working face 2 to be mined.

[0296] It is understood that the specific locations of the horizontal sections of the low-level and high-level horizontal well groups are determined based on the width of the working face 2 to be mined and the development of mining-induced fissures. The selection of these locations must take into account the influence range of mining-induced fissures to ensure that the fracturing boundaries of the horizontal wells are located outside the influence range of mining-induced fissures, thereby avoiding leakage and affecting the fracturing effect.

[0297] In the absence of mining cracks, the horizontal well is generally located at half the width of the mining face 2. This location is chosen to ensure that the fracture network can evenly cover the entire mining face 2 and improve the coal seam roof fracturing effect.

[0298] In some embodiments, estimating the construction length of the ground horizontal well includes: estimating based on the burial depth of the fractured layer, and the horizontal section lengths of the low-level horizontal well group and the high-level horizontal well group are less than twice the burial depth of the corresponding fractured layer.

[0299] It's understandable that estimating the construction length of a surface horizontal well requires first understanding the rock depth of the fracture zone. This can generally be accomplished through geological exploration and data analysis. Understanding the rock depth helps determine the appropriate depth for horizontal well construction, ensuring that the well can effectively extend into the coal seam and cover sufficient fracture area.

[0300] After determining the burial depth of the rock formation where the fracturing layer is located, the designed length of the horizontal section should be less than twice its burial depth. This means that the length of the horizontal section should be moderate, neither too short to cover sufficient fracturing area nor too long to exceed the construction capacity.

[0301] Therefore, through reasonable length estimation, it can be ensured that the horizontal well can cover a sufficient fracturing area and improve the fracturing effect; moderate horizontal section length helps to reduce construction costs and reduce unnecessary resource consumption.

[0302] In some embodiments, the ground multi-horizontal well layout method of an embodiment of the present invention also includes a third well group, the third well group includes a third low-level horizontal well and a third high-level horizontal well, the first well group 5, the second well group 6 and the third well group are arranged in sequence in the direction of the working face 2 to be mined, and the horizontal section of the third low-level horizontal well and the horizontal section of the third high-level horizontal well both extend in the direction from the third well group to the second well group 6.

[0303] It is understood that the third well group consists of a third low-level horizontal well and a third high-level horizontal well. While similar in design to the first well group 5 and the second well group 6, the first well group 5, the second well group 6, and the third well group are arranged in sequence, spaced apart in the direction of the working face 2 to be mined, to form a nearly continuous fracturing system. In other words, the addition of the third well group expands the fracturing range, ensuring effective fracturing of the coal seam roof across the entire working face 2 to be mined, and increasing the coverage of the fracturing network over the working face 2 to be mined.

[0304] It should be noted that the horizontal well layout positions for the entire working face 2 to be mined are based on the strike length of the working face 2 to be mined and the maximum length of the horizontal section of the horizontal well. For example, if the strike length of a working face 2 to be mined is 3,600m and the fractured layer rock stratum is 600m deep, it is estimated that the maximum construction length of the horizontal section is 1,200m. To achieve fracture coverage of the entire working face 2 to be mined, three horizontal wells (i.e., the first well group 5, the second well group 6, and the third well group) need to be arranged along the strike direction, of which two horizontal wells (i.e., the first well group 5 and the second well group 6) are arranged in a split manner. Generally, the horizontal wells arranged in a split manner are arranged close to the cut-eye direction of the working face 2 to be mined, with the bottom of the horizontal well close to the cut-eye position. The other horizontal well can be drilled near the withdrawal area and drilled in the direction of the cut-eye.

[0305] In some embodiments, during construction, monitoring equipment is used to monitor the expansion of the fracture network during fracturing.

[0306] It is understood that during construction, monitoring equipment (such as acoustic transmitters and microseismic monitoring systems) is installed to monitor the expansion of the fracture network in real time during fracturing. This monitoring equipment provides real-time data during the fracturing process, helping technicians understand the expansion and morphology of the fracture network and adjust fracturing parameters in a timely manner.

[0307] In other words, real-time analysis of data collected by monitoring equipment, including acoustic signals and microseismic events, is used to assess the effectiveness of the fracture network expansion. This data analysis can help technicians quickly identify abnormalities during the fracturing process, such as uneven fracture network expansion and poor fracturing results, allowing them to take timely corrective measures.

[0308] Based on monitoring data and analysis results, fracturing operation parameters such as injection pressure, injection rate, and liquid properties are adjusted in real time. Through real-time adjustments, it is possible to ensure that the fracturing effect meets expectations, improve fracturing efficiency, and reduce resource waste.

[0309] According to the attached Figure 16-18 The following examples are described.

[0310] In some embodiments, the implementation of the combined well fracturing method of surface horizontal wells and surface vertical wells further includes the following steps:

[0311] Construct a joint well group, one of the joint well groups includes a ground horizontal well and multiple vertical wells. Before the excavation and mining of the first mining working face, in the first mining working face and the second working face, a ground horizontal well is arranged in the coal pillar area between the first mining working face and the second working face and in one of the second working faces, and fracturing construction is carried out. In the second working face, multiple vertical wells are constructed along the direction of the working face, and fracturing construction is carried out. Alternatively, after the excavation and mining of the first mining working face, a ground horizontal well is arranged along the direction of the working face in the second working face, and fracturing construction is carried out. Multiple vertical wells are constructed along the direction of the working face, and fracturing construction is carried out. There are multiple joint well groups, and the multiple joint well groups are arranged in sequence along the inclination of the working face.

[0312] It is understandable that if Figure 16 and Figure 17 As shown, the first mining working face 81, the second working face 82 and the third working face 83 are arranged in sequence along the inclination direction of the working face. Before the first mining working face 81 is mined, a ground horizontal well 7 is arranged in the area above the coal pillar 200 between the two adjacent working faces (i.e., the first mining working face 81 and the second working face 82), and fracturing construction is carried out, wherein the arrangement of the ground horizontal well 7 is used to pre-crack and weaken the impact-causing rock formation, and the horizontal extension direction of the ground is consistent with the strike direction of the working face, so as to achieve overall fracturing and weakening of the thick hard roof above the coal pillar 200. At the second working face 82, multiple vertical wells 2 are constructed along the strike direction of the working face, and fracturing construction is carried out to pre-crack and weaken the mine earthquake-causing rock formation, so as to achieve regional and advanced governance. There are multiple joint well groups, which are arranged in sequence along the inclination of the working face to ensure the fracturing coverage and effect of the thick hard roof of the entire coal seam 100 mining area. Among them, the vertical well fracturing range 31 is as follows Figure 16 and Figure 18 As shown in .

[0313] In other words, the combined well layout method of the surface horizontal well 7 and vertical well 2 in the embodiment of the present invention allows for fracturing operations in the surface horizontal well 7 to effectively cover the thick hard roof above the coal pillar 200, reducing the occurrence of fracturing blind spots and improving pressure relief. Fracturing operations in the vertical well 2 can pre-crack and weaken the multiple layers of thick hard roof, reducing the risk of mine tremors. This combined well layout ensures the continuity and coordination of fracturing measures in space and time, improving the prevention and control of rock bursts and mine tremors.

[0314] In other embodiments, Figure 18As shown, after the first mining face 81 is mined, at the second working face 82, ground horizontal wells 7 and multiple vertical wells 2 are arranged at intervals along the inclination of the working face. The extension direction of the ground horizontal well 7 is consistent with the strike of the working face 2 to be mined, so as to be used for fracturing and weakening low-level impact-causing rock formations. In the strike direction of the working face 2 to be mined, multiple vertical wells 2 are arranged in sequence at intervals. The vertical wells 2 are used to fracture and weaken high-level mine earthquake-causing rock formations. The vertical wells 2 and the ground horizontal wells 7 are relatively arranged on both sides of the extension direction of the center line of the working face 2 to be mined to achieve a uniform fracturing effect.

[0315] In other words, the combined layout of horizontal wells 7 and vertical wells 2 in the embodiment of the present invention effectively weakens hazard-causing rock formations at different levels, improving the effectiveness of preventing rock bursts and mine tremors. This reduces the number of wellheads, simplifies construction organization, and shortens the construction period. It also mitigates the impact of surface topography and land acquisition difficulties on construction.

[0316] Thus, the combined layout of surface horizontal wells 7 and vertical wells 2 in the embodiment of the present invention comprehensively considers the geological conditions and mining layout of the mine area, optimizing the fracturing operation parameters and well layout. The combined layout of surface horizontal wells 7 and vertical wells 2 fully leverages the respective advantages of the two fracturing methods, achieving complementary fracturing effects. This not only increases the fracturing coverage, reduces fracturing blind spots, and improves the pressure relief effect, but also helps reduce the risk of rock bursts and mine tremors, ensuring safe mine production.

[0317] In some embodiments, determining the mine geological conditions and fracturing construction parameters includes: collecting the geological conditions and fracturing construction parameters of the pre-construction mine or the geological conditions and fracturing construction fracture network expansion similar to the pre-construction mine for comparison according to the corresponding geological conditions and construction parameters.

[0318] It is understood that detailed information on the geological conditions, fracturing operation parameters, and fracture network expansion of the proposed mine should be collected, including but not limited to rock physical and mechanical properties, ground stress distribution, groundwater conditions, and structural characteristics of the roof rock strata. If the current mine has no direct experience with fracturing, relevant data from mines with similar geological conditions will be collected. In other words, by collecting existing data, it can provide a reference for new mines and help technicians better understand and predict the effects of upcoming fracturing operations.

[0319] A systematic analysis of the collected data includes an evaluation of geological similarities, an assessment of the suitability of fracturing parameters, and a comparative study of fracturing network expansion. This comparative analysis identifies the geological conditions and fracturing parameters appropriate for the current mine. This comparative analysis reveals similarities and differences between different mines, helping to determine the most appropriate fracturing plan for the mine and reducing uncertainty and potential risks during the operation.

[0320] Based on the collected data and comparative analysis results, necessary adjustments and optimizations are made to the fracturing operation parameters to ensure the scientific and effective operation plan. These parameter adjustments and optimizations can better adapt to the geological conditions of a specific mine, increase the success rate of fracturing operation, reduce construction costs, and improve mine safety.

[0321] This comparative analysis can help avoid repeating the failures of other mines, draw lessons from successful cases, and provide stronger technical support for mine safety production. It also helps optimize resource allocation, improve fracturing efficiency, and reduce production costs. It provides a scientific basis for long-term mine planning and safe production, and helps improve overall mine management.

[0322] In some embodiments, before constructing the joint well group, the following steps are also included: collecting the working face width, analyzing the development of lateral mining cracks on the working face, and based on the estimated fracture network, the working face width, and the development of mining cracks, when there is an impact of mining cracks, the fracturing boundaries of the ground horizontal well 7 and / or vertical well 2 are located outside the impact range of the mining cracks; when there is no impact of mining cracks, the position of the ground horizontal well 7 and / or vertical well 2 is roughly located in the middle of the working face.

[0323] It is understandable that if Figure 16 As shown, before the initial mining face 81 is excavated and mined, the surface horizontal well 7 can be arranged on the coal pillar 200 between two adjacent working faces, or on other working faces other than the initial mining face 81. The vertical well 2 can only be arranged on other working faces other than the initial mining face 81.

[0324] That is to say, before the excavation and mining of the first mining working face 81, the layout of the ground horizontal well 7 can be in two ways, namely, the first layout method is: the ground horizontal well 7 is arranged in the rock layer above the coal pillar 200 between the first mining working face 81 and the second working face 82, and in this layout method, the layout of the ground horizontal well 7 must be completed before the layout of the vertical well 2; the second layout method is: the ground horizontal well 7 and the vertical well 2 can be constructed simultaneously at the second working face 82 to improve construction efficiency.

[0325] After the excavation and mining of the first mining working face 81, the influence of mining-induced cracks, that is, the development of mining-induced cracks, needs to be considered. When there is the influence of mining-induced cracks, the fracturing boundaries of the ground horizontal well 7 and the vertical well 2 are located outside the influence range of mining-induced cracks. When there is no influence of mining-induced cracks, the positions of the ground horizontal well 7 and the vertical well 2 are roughly located in the middle of the working face.

[0326] In other words, by optimizing well location and fracturing parameters, fracturing resources can be more efficiently utilized and unnecessary waste reduced. Ensuring that fracturing measures cover the target area can more effectively mitigate the risks of rock bursts and mine tremors. Improving fracturing efficiency can reduce the cost of the entire fracturing process and improve the economic benefits of the mine.

[0327] In some embodiments, the method for jointly deploying horizontal wells 7 and vertical wells 2 on the ground based on global considerations of the mining area in the embodiments of the invention further includes determining the distance between two adjacent vertical wells 2, and determining the spacing between the vertical wells 2 based on the periodic breaking step of the high-level thick hard roof and the width of the fracture network of the vertical wells 2. Among them, H is the spacing between vertical wells 2, h1 is the width of the fracture network in vertical well 2, and h2 is the periodic fracture step distance of the high-position thick hard roof.

[0328] It is understandable that if Figure 16 As shown in the figure, when laying vertical wells 2, it is necessary to determine the distance between two adjacent vertical wells 2. Among them, h1 is the width of the fracture network of vertical well 2, that is, the width of the fracture network formed around the vertical well 2 by fracturing construction; h2 is the periodic breaking step distance of the high-position thick hard roof, that is, the distance from the beginning of the high-position thick hard roof to the next breaking. The distance between two adjacent vertical wells 2 can be calculated.

[0329] That is to say, through the above calculations, a reasonable spacing between vertical wells 2 can be determined so that the fracture network generated by each vertical well 2 can effectively cover the influence range of the adjacent vertical well 2. At the same time, the periodic breaking characteristics of the roof are taken into account to ensure that the roof can be effectively controlled during periodic breaking.

[0330] In other words, through geological surveys, rock mechanics testing, and numerical simulations, we collected data on the periodic fracture steps of the high-level thick hard roof and the width of the fracture network generated by the vertical well 2 fracturing. The vertical well 2 spacing H is calculated using the above formula to ensure that the fracture networks between each vertical well 2 can overlap with each other to form a continuous fracture zone. Based on the calculated vertical well 2 spacing H, vertical wells 2 are arranged laterally on the working face above the coal pillar 200 to ensure that the fracturing effect of vertical well 2 can cover the entire high-level thick hard roof. Real-time monitoring is carried out during the fracturing process, and the vertical well 2 spacing is adjusted based on the monitoring results to optimize the fracturing effect.

[0331] In some embodiments, the distances from the vertical wells 2 to both sides of the working surface are substantially equal. It will be appreciated that the distances from the vertical wells 2 to both sides of the working surface are typically measured and calculated to ensure that the fracturing effect is uniform on both sides of the working surface. Based on the calculated distances, the vertical wells 2 are evenly arranged so that the distances from each vertical well 2 to both sides of the working surface are similar. Furthermore, during the fracturing process, the fracturing effect of the vertical wells 2 can be monitored in real time through a monitoring system, and necessary adjustments can be made based on actual conditions to ensure uniform coverage of the roof on both sides of the working surface.

[0332] In other words, selecting the appropriate location for vertical well 2 based on the actual working face conditions ensures uniform fracturing of the roof on both sides of the working face, facilitating overall pressure relief and reducing roof stability issues caused by uneven pressure. This evenly distributed well arrangement helps better control roof stability and reduces the risk of rock bursts and mine tremors caused by roof instability.

[0333] In some embodiments, the ground horizontal well 7 includes a vertical section, a deflection section and a horizontal section connected in sequence, and the length of the horizontal section in its extension direction is greater than the length of the fracture range formed by multiple vertical wells 2 in the extension direction of the horizontal section.

[0334] It is understood that when designing the surface horizontal well 7, the length of the horizontal section is calculated and determined to ensure that it is longer than the fracture range formed by the vertical well 2. The horizontal section is constructed according to the designed length to ensure that it has sufficient horizontal extension. This allows for fracturing operations to be carried out in the horizontal section, taking advantage of the length of the horizontal section and ensuring that the fracture is fully expanded throughout the entire working surface.

[0335] In other words, ensuring that the length of the horizontal section is sufficient to cover the fractures created by multiple vertical wells 2 improves the overall effectiveness and coverage of the fracturing. By increasing the length of the horizontal section, blind spots that may form due to insufficient fracture coverage can be reduced or eliminated. By properly designing the horizontal section length, fracturing resources can be more efficiently utilized and waste avoided. Effective fracturing helps improve mine safety and reduce the risk of rock bursts and mine tremors caused by roof instability.

[0336] In some embodiments, before the tunnel excavation and mining of the first mining working face 81, a ground horizontal well 7 is first arranged in the direction of the coal pillar 200 between the first mining working face 81 and the second working face 82, and then before the tunnel excavation and mining of the second working face 82, a vertical well 2 is constructed in the second working face 82, and the subsequent construction of the vertical well 2 and the ground horizontal well 7 are all carried out according to the previous steps; or, at the same time, a ground horizontal well 7 is arranged in the direction of the coal pillar 200 between the first mining working face 81 and the second working face 82, and a vertical well 2 is constructed in the second working face 82, and the subsequent construction of the vertical well 2 and the ground horizontal well 7 are all carried out according to the previous steps.

[0337] It is understandable that before the tunnel excavation and mining of the first mining face 81, there are two ways of arranging wells for fracturing, namely, the first is to carry out fracturing construction of the horizontal well 7 and the vertical well 2 on the ground in sequence. First, the coal pillar 200 between the first mining face 81 and the second working face 82 is subjected to horizontal well fracturing, and then the vertical well 2 is fracturing on the second working face 82. The subsequent working faces also carry out corresponding fracturing construction in this order. By carrying out fracturing construction in accordance with the mining sequence, it can be ensured that the roof of each working face has been fully weakened by fracturing before mining, reducing the risk of rock burst and mine tremors during the mining process.

[0338] The second is to carry out fracturing construction of the ground horizontal well 7 and the vertical well 2 at the same time. It can be understood that simultaneous fracturing means that the fracturing weakening of the coal pillar 200 (horizontal well target area) between the first mining working face 81 and the second working face 82 and the roof of the second working face 82 (vertical well 2 target area) are completed almost simultaneously. Simultaneous construction can form connected weakened areas in a larger range and earlier, providing more timely and more coherent roof weakening protection for the mining of the first mining working face 81 and the subsequent second working face 82. From the perspective of the entire mining area, overall safety may be established earlier and more comprehensively.

[0339] It should be noted that before the excavation and mining of the first mining face 81, whether in the first well layout method or the second well layout method, the ground horizontal well 7 needs to be arranged first, and then the vertical well 2 is constructed before the excavation and mining of the second working face 82 according to the mining sequence.

[0340] In other words, the mining sequence for each working face is determined based on the mining area plan and geological conditions. Following this mining sequence, horizontal wells 7 and vertical wells 2 are deployed sequentially. Following this well deployment sequence, hydraulic fracturing is performed on these wells 7 and 2, respectively. During the fracturing process, the fracturing effect is monitored in real time, and adjustments are made based on the monitoring results to ensure the desired results.

[0341] In some embodiments, after the tunnel excavation and mining of the first mining face 81 and before the excavation and mining of the second working face 82, the ground horizontal well 7 and the vertical well 2 are simultaneously constructed at the second working face 82, and the subsequent construction of the vertical well 2 and the ground horizontal well 7 are carried out in accordance with the previous steps.

[0342] It is understood that after the initial mining face 81 is mined and before the second working face 82 is excavated and mined, fracturing operations are simultaneously performed in the horizontal well and the vertical well 2 in the area of ​​the second working face 82. When there are mining-induced fissures, the fracturing boundaries of the surface horizontal well 7 and the vertical well 2 are both located outside the range of the mining-induced fissures. When there are no mining-induced fissures, the surface horizontal well 7 and the vertical well 2 are located approximately in the middle of the second working face 82.

[0343] It is understandable that, according to the mining order of the working faces, the fracturing construction of the ground horizontal well 7 and the vertical well 2 is carried out in sequence. First, the coal pillar 200 between the first mining working face 81 and the second working face 82 is subjected to horizontal well fracturing, and then the vertical well 2 is subjected to fracturing on the second working face 82. The subsequent working faces also undergo corresponding fracturing construction in this order. By carrying out fracturing construction in accordance with the mining order, it can be ensured that the roof of each working face has been sufficiently weakened by fracturing before mining, thereby reducing the risk of rock burst and mine tremors during the mining process.

[0344] In other words, the mining sequence for each working face is determined based on the mining area plan and geological conditions. Following this mining sequence, horizontal wells 7 and vertical wells 2 are deployed sequentially. Following this well deployment sequence, hydraulic fracturing is performed on these wells 7 and 2, respectively. During the fracturing process, the fracturing effect is monitored in real time, and adjustments are made based on the monitoring results to ensure the desired results.

[0345] In some embodiments, when the rock burst control layer and the mine shock control layer are unstable and the number of fracturing layers exceeds three, the construction of the surface vertical well fracturing method further includes the following steps:

[0346] A plurality of ground vertical wells are arranged in sequence along the strike direction of the working face on the ground, and a staged fracturing process is used to implement fracturing on each thick hard roof plate. The method also includes a plurality of ground vertical well groups, one of which includes the plurality of ground vertical wells, and the plurality of ground vertical well groups are arranged at intervals along the dip direction of the working face.

[0347] It's understandable that multiple surface vertical wells are arranged at regular intervals along the strike direction of the working face. This arrangement helps create effective fracturing coverage within the plane and reduces fracturing blind spots. Each thick hard roof plate is subjected to a staged fracturing process. This means each thick hard roof plate is divided into several sections and fractured separately, effectively weakening the multiple layers of the roof plate. Multiple surface vertical wells form a surface vertical well group, which is spaced along the dip direction of the working face. This arrangement helps create multiple layers of fracturing zones in the vertical direction, effectively controlling the roof plate in different areas.

[0348] In other words, by arranging vertical wells on the surface, the fracturing strategy can be flexibly adjusted based on the specific geological conditions and roof strata characteristics to adapt to the complex and changing mining environment. This layered and staged fracturing process helps target critical risk zones, avoids ineffective operations in non-risk zones, and improves resource utilization efficiency. By coordinating the management of rock bursts and mine tremors, the risk of disasters is reduced, miners' lives are protected, and the safety level of mining operations is improved.

[0349] According to the attached Figures 19-21 The following examples are described.

[0350] In some embodiments, the method for coordinated control of rock burst and mine tremors based on regional fracturing according to an embodiment of the present invention further includes the following steps:

[0351] S6. During the fracturing and production periods, monitor and evaluate the regional fracturing pressure relief effect to effectively guide the optimization of the regional fracturing plan. Monitoring can be achieved through the ground microseismic system. The specific steps are as follows:

[0352] S101: Through the microseismic probe (such as Figure 20 (as shown in the reference numeral 2-1) to monitor microseismic data in real time;

[0353] S102: Determine, based on the microseismic monitoring data during the statistical period, a microseismic event dispersion ratio between the fractured area and the unfractured area, a microseismic event total energy ratio between the fractured area and the unfractured area, and a transmission frequency ratio of high-energy microseismic events with energy greater than a preset value;

[0354] S103: Determine the comprehensive pressure relief effect based on the microseismic event dispersion ratio between the fractured area and the unfractured area, the total energy ratio of the microseismic events between the fractured area and the unfractured area, and the transmission frequency ratio of high-energy microseismic events with energy greater than a preset value.

[0355] Based on the above embodiment, this embodiment describes step S101 in detail:

[0356] like Figure 20In one embodiment, before the working face is mined, no less than four microseismic probes need to be arranged in the transport tunnel and the return air tunnel to implement envelope monitoring of the ground fracturing area within the mining range of the working face. The layout and spacing of the probes need to be optimized according to the specific conditions of the working face to ensure that microseismic events can be fully and accurately monitored. As the mining of the working face progresses, the probes need to be moved accordingly to maintain effective monitoring of the fracturing area. The probe spacing is generally controlled between 200 and 500 meters to ensure the coverage and accuracy of the monitoring.

[0357] Microseismic signals collected by microseismic probes require data processing, including signal filtering, noise removal, and feature extraction. Professional data processing software and algorithms can accurately determine characteristic parameters such as the location and energy of microseismic events. This processed data serves as the basis for evaluating fracturing effectiveness.

[0358] like Figure 21 Based on the above embodiment, this embodiment describes step S102 in detail:

[0359] The dispersion of microseismic events can indicate the concentration of microseismic events during the mining period. A concentrated distribution indicates a high stress concentration and relative danger; a dispersed distribution indicates a low stress concentration and relative safety. In one embodiment, the ratio of the microseismic event dispersion between the fractured area and the unfractured area is determined based on the microseismic monitoring data during the statistical period, including:

[0360] Determine the average value of the sum of the squares of the distances from each microseismic event to the mean point of the microseismic events within the fracturing area during the statistical period, which is the microseismic event dispersion of the fracturing area;

[0361] Determine the average value of the sum of the squares of the distances from each microseismic event to the mean point of the microseismic events in the unfractured area during the statistical period, which is the microseismic event dispersion of the unfractured area;

[0362] Determine the dispersion ratio of microseismic events in the fractured area and the unfractured area.

[0363] Specifically, the calculation formula is as follows:

[0364] Calculate the mean value of microseismic event points during the statistical period (x v ,y v ):

[0365]

[0366] Calculate the distance di from each microseismic event to the mean point during the statistical period:

[0367]

[0368] Calculate the microseismic event dispersion S:

[0369]

[0370] After regional fracturing, the energy accumulated in the surrounding rock of the working face is released in advance, and the energy of microseismic events during the working face mining period is reduced, indicating that the impact risk is reduced. In one embodiment, the ratio of the total energy of microseismic events in the fractured area and the unfractured area is determined based on microseismic monitoring data during the statistical period, including:

[0371] Based on the microseismic monitoring data during the statistical period, the total energy of microseismic events in the fractured area and the unfractured area is determined according to the magnitude-energy relationship, or

[0372] Based on the microseismic monitoring data during the statistical period, the total energy of microseismic events in the fractured area and the unfractured area is determined according to the total number of sampling points, signal amplitude and sensor impedance value, or

[0373] Based on the microseismic monitoring data during the statistical period, the total energy of microseismic events in the fractured and unfractured areas is determined according to the energy attenuation model, combined with the peak vibration velocity, focal distance and energy characteristic coefficient;

[0374] Determine the ratio of the total energy of microseismic events in the fractured area to that in the unfractured area.

[0375] The specific calculation formula is as follows:

[0376] The energy of a microseismic event can be calculated using the relationship between magnitude and energy. This relationship between magnitude (M) and energy (E) is: log E = a + bM, where a and b are constants that depend on the specific geological conditions and monitoring system. After determining these parameters through regression analysis, the energy of a microseismic event can be calculated based on its magnitude.

[0377] For non-localized events or when energy needs to be calculated directly from waveform data, the following formula can be used:

[0378]

[0379] Where: N is the total number of sampling points; X k is the signal amplitude (unit: volts); Ω is the sensor impedance value.

[0380] Through the energy attenuation model, combined with the peak vibration velocity, focal distance and energy characteristic coefficient, the source energy can be inverted:

[0381]

[0382] Among them, E i is the energy of the i-th microseismic event, D i is the focal distance of the ith microseismic event, V iis the peak vibration velocity of the i-th microseismic event, the energy characteristic coefficient (G is the shear modulus, which represents the shear stiffness of the rock material, and W Li is the attenuation factor on the propagation path of the i-th microseismic event, A i is the amplification coefficient on the propagation path of the i-th microseismic event, T Liik is the amplification factor on the propagation path of the i-th microseismic event, and g is the acceleration of gravity).

[0383] Regional fracturing reduces high-energy events during mining at the working face, weakens the impact on the tunnel, and indicates that the impact risk is reduced. In one embodiment, the preset value is 10 4 J.

[0384] Based on the above embodiment, this embodiment describes step S103 in detail:

[0385] The above indicators are compared with the monitoring indicators of the non-impact hazard area. During the actual working face mining, it is necessary to monitor the tunnel roof sinking, bottom bulging, and two-side convergence in real time, and compare the correction indicators of the tunnel roof sinking, bottom bulging, and two-side convergence in the non-impact hazard area. When the roof sinking, bottom bulging, and two-side convergence in the fracturing area are equal to the tunnel roof sinking, bottom bulging, and two-side convergence in the non-impact hazard area, the corresponding three indicators are the microseismic event discreteness, microseismic event energy reduction rate, and high-energy event (104J and above event) frequency reduction rate, and the indicators are further corrected. In one embodiment, based on the ratio of the microseismic event discreteness of the fracturing area and the unfracturing area, the ratio of the total energy of the microseismic events in the fracturing area and the unfracturing area, and the ratio of the frequency of high-energy microseismic events with energy greater than a preset value, before determining the comprehensive pressure relief effect, it also includes:

[0386] Real-time monitoring of the tunnel roof subsidence, floor bulge and two-wall convergence through tunnel deformation monitoring equipment;

[0387] Based on the benchmark values ​​of the tunnel roof subsidence, floor heave and two-wall convergence in the non-impact hazard area, the microseismic event dispersion ratio, the total energy ratio of microseismic events and the frequency ratio of high-energy microseismic events with energy greater than the preset value in the fracturing area are corrected.

[0388] Specifically, in one embodiment, based on the reference values ​​of the roadway roof subsidence, floor heave, and two-wall convergence in the non-impact hazard zone, the microseismic event dispersion ratio, the microseismic event energy sum ratio, and the high-energy microseismic event transmission frequency ratio in the fracturing zone are corrected, including:

[0389] When the error range between the microseismic event discreteness of the fracturing area and the roadway roof subsidence reference value is less than the first preset condition, the microseismic event discreteness of the fracturing area is corrected to the roadway roof subsidence reference value;

[0390] When the error range between the total energy of microseismic events in the fracturing area and the reference value of the floor drum is less than a second preset condition, the total energy of microseismic events in the fracturing area is corrected to the reference value of the floor drum;

[0391] When the error range between the frequency of sending high-energy microseismic events with energy greater than the preset value in the fracturing area and the reference value of the convergence amount of the two gangs is less than the third preset condition, the frequency of sending high-energy microseismic events with energy greater than the preset value in the fracturing area is corrected to the reference value of the convergence amount of the two gangs.

[0392] Based on the above embodiments, in one embodiment, determining the comprehensive pressure relief effect based on the microseismic event dispersion ratio between the fractured area and the unfractured area, the total energy ratio of the microseismic events between the fractured area and the unfractured area, and the transmission frequency ratio of high-energy microseismic events with energy greater than a preset value includes:

[0393] When the ratio of the microseismic event discreteness between the fractured area and the unfractured area is greater than a first threshold, the pressure relief effect is good. In one embodiment, when the ratio of the microseismic event discreteness between the fractured area and the unfractured area M=S2 / S1>70%, it indicates that the pressure relief effect is good, where S1 is the microseismic event discreteness in the unfractured area, and S2 is the microseismic event discreteness in the fractured area.

[0394] When the ratio of the total energy of microseismic events in the fractured area and the unfractured area is determined to be less than a second threshold value, the unloading effect is good. In one embodiment, the microseismic event energy reduction rate D = Q2 / Q1. When D < 60%, it indicates that the unloading effect is good, where Q1 is the energy of microseismic events in the unfractured area and Q2 is the energy of microseismic events in the fractured area.

[0395] When the ratio of the frequency of high-energy microseismic events in the fractured area and the unfractured area with energy greater than a preset value is less than a third threshold, the pressure relief effect is good. In one embodiment, the frequency reduction rate of high-energy events (104J and above events) P ​​= P2 / P1. When P<50%, it indicates that the pressure relief effect is good, where P1 is the frequency of high-energy microseismic events in the unfractured area, and P2 is the frequency of high-energy microseismic events in the fractured area.

[0396] When the three indicators are evaluated as good, the comprehensive pressure relief effect is excellent. When the comprehensive pressure relief evaluation indicators are excellent, there is no impact hazard, and the area can be managed as a non-impact hazard area without implementing additional pressure relief measures.

[0397] When the two indicators are evaluated as good, the comprehensive pressure relief effect is good;

[0398] When one indicator is evaluated as good, the overall pressure relief effect is medium;

[0399] When it is determined that no indicator is evaluated as good, the comprehensive pressure relief effect is poor.

[0400] The above-mentioned indicators may be indicators before or after correction, and both methods fall within the protection scope of the present invention.

[0401] The embodiment of the present invention further provides a regional fracturing effect evaluation device based on microseismic monitoring; the specific device may include:

[0402] A data acquisition module, used for real-time monitoring of microseismic data through a microseismic probe;

[0403] An indicator determination module is used to determine, based on the microseismic monitoring data during the statistical period, a microseismic event dispersion ratio between the fractured area and the unfractured area, a microseismic event total energy ratio between the fractured area and the unfractured area, and a transmission frequency ratio of high-energy microseismic events with energy greater than a preset value;

[0404] The effect evaluation module is used to determine the comprehensive unloading effect based on the ratio of the microseismic event dispersion in the fractured area and the unfractured area, the ratio of the total energy of the microseismic events in the fractured area and the unfractured area, and the ratio of the frequency of high-energy microseismic events with energy greater than a preset value.

[0405] This embodiment is used to implement the aforementioned regional fracturing effect evaluation method based on microseismic monitoring. Therefore, the specific implementation of the regional fracturing effect evaluation device based on microseismic monitoring can be seen in the embodiment part of the regional fracturing effect evaluation method based on microseismic monitoring above. For example, the data acquisition module, the indicator determination module, and the effect evaluation module are respectively used to implement steps S101, S102, and S103 in the aforementioned regional fracturing effect evaluation method based on microseismic monitoring. Therefore, its specific implementation can refer to the description of the corresponding embodiments, and will not be repeated here.

[0406] According to the attached Figure 22 and Figure 23 The following examples are described.

[0407] S7. Select evaluation factors when rock burst occurs at the mining face, draw a basic base map of the mining face in a preset drawing software, and compile a rock burst prevention and control effect tracking and evaluation map based on the collected relevant data. Based on the rock burst prevention and control effect tracking and evaluation map, analyze the roof lithologic characteristics, cloud pressure pattern, ground subsidence, completed pressure relief projects and mining intensity to predict the rock burst hazard level of the mining face at different time periods.

[0408] The evaluation method further comprises the following steps:

[0409] like Figure 22As shown, step 101 selects evaluation factors when rock burst occurs in the mining face, wherein the evaluation factors include roof lithology data of the mining face, ground settlement data, support pressure data, mining intensity data, microseismic monitoring data, mining position of the working face and pressure relief engineering quantity data.

[0410] In some possible implementations, by combining the depth change characteristics of the mining face, structural characteristics, roof lithology, regional and local unloading methods, rock burst monitoring data, surface subsidence, and mining intensity, evaluation factors are designed and selected when rock burst occurs in the mining face. The evaluation factors are continuously tracked and coordinated on the same time or distance axis to achieve comprehensive tracking and evaluation of the rock burst prevention and control effects.

[0411] like Figure 22 As shown, in step 102, a basic base map of the mining face is drawn in a preset drawing software, wherein the basic base map is based on the mining map of the mining face, the mining face cut eye is 0m mileage, and the mining direction is the positive direction.

[0412] In some possible implementations, the preset drawing software can be computer-aided design (CAD). Specifically, in CAD, the mining face map is used as the base map, the face cut is set at 0 m mileage, the mining direction is the positive direction, and the working face mining position is used as the horizontal coordinate. The horizontal coordinates of each evaluation factor are normalized to provide a preliminary upper limit length for the vertical coordinate. A preliminary anti-bumping effect tracking evaluation base map is designed, and the mining face map can be drawn with an aspect ratio of 1:0.2. The vertical coordinate is composed of data from each evaluation factor, such as daily microseismic energy, daily microseismic frequency, and daily mining footage of the working face.

[0413] like Figure 22 As shown, step 103, based on the roof lithology data, ground settlement data, support pressure data, mining intensity data, microseismic monitoring data, working face mining position and unloading engineering quantity data, the working face mining mileage is used as the horizontal coordinate, the initial upper limit length of the vertical coordinate is set, and the roof lithology distribution map, ground settlement curve map, support pressure cloud map, unloading engineering / mining position map, microseismic daily frequency / daily energy / daily mining footage trend map are drawn in the basic base map according to different horizontal and vertical ratios, and a map for tracking and evaluating the impact ground pressure prevention and control effect is formed.

[0414] In some possible implementations, a graph for tracking and evaluating rock burst prevention and control effects is constructed, including: normalizing the horizontal coordinate of roof lithology data, taking the working face mining mileage as the horizontal coordinate, and drawing a roof lithology distribution map in the basic base map according to a first horizontal-to-vertical ratio within a set initial upper limit length of the ordinate; normalizing the horizontal coordinate of ground settlement data, taking the working face mining mileage as the horizontal coordinate, and drawing a ground settlement curve map in the basic base map according to a second horizontal-to-vertical ratio within a set initial upper limit length of the ordinate; normalizing the horizontal coordinate of support pressure data, taking the working face mining mileage as the horizontal coordinate, and drawing a support pressure cloud map in the basic base map according to a third horizontal-to-vertical ratio within a set initial upper limit length of the ordinate; Normalize the horizontal coordinates of the working face mining position and pressure relief engineering quantity data, use the working face mining mileage as the benchmark as the horizontal coordinate, and within the set initial upper limit of the vertical coordinate, draw a pressure relief engineering / mining position map in the basic base map according to the fourth horizontal and vertical ratio; normalize the horizontal coordinates of the mining intensity data and microseismic monitoring data, use the working face mining mileage as the benchmark as the horizontal coordinate, and within the set initial upper limit of the vertical coordinate, draw a microseismic daily frequency / daily energy / daily mining footage trend map in the basic base map according to the fifth horizontal and vertical ratio; combine the roof lithology distribution map, ground settlement curve map, support pressure cloud map, pressure relief engineering / mining position map, microseismic daily frequency / microseismic daily energy / daily mining footage trend map into a map for tracking and evaluating the impact ground pressure prevention and control effect.

[0415] Optionally, the horizontal coordinate of the roof lithologic data is normalized, and the working face mining mileage is used as the horizontal coordinate, and within the set initial upper limit length of the vertical coordinate, the roof lithologic distribution map is drawn in the basic base map according to the first horizontal-to-vertical ratio, including: when the first horizontal-to-vertical ratio is 1:1, the horizontal coordinate of the roof lithologic data is normalized, and the working face mining mileage is used as the horizontal coordinate, and the lithologic profiles of the roof, coal seam and floor in the roof lithologic data are drawn in the basic base map according to the horizontal-to-vertical ratio of 1:1, and the initial vertical coordinate is set. Within the limited length, mark out the single-layer sandstone / conglomerate with a thickness of more than 10m or the sandstone / conglomerate group with a thickness of more than 20m, and mark out the lithologic mutation area. The vertical coordinate 0m is the starting position of the coal seam roof to obtain the roof lithologic distribution map, wherein the vertical coordinate is determined by the inclination of the coal seam and the key anti-bumping layer within 100m above the coal seam. The inclination of the coal seam is determined by the mining mileage of the working face. The key anti-bumping rock layer within 100m above the coal seam is composed of the single-layer sandstone / conglomerate with a thickness of more than 10m or the sandstone / conglomerate group with a thickness of more than 20m.

[0416] The bottom plate lithologic profile is generally from 100m of the coal seam roof to 10m of the coal seam bottom plate, but is not limited to this.

[0417] Optionally, the horizontal coordinate of the ground subsidence data is normalized, and the working face mining mileage is used as the horizontal coordinate, and within the set initial upper limit length of the vertical coordinate, a ground subsidence curve is drawn in the basic base map according to the second horizontal and vertical ratio, including: when the second horizontal and vertical ratio is 1:100, the horizontal coordinate of the ground subsidence data is normalized, and the working face mining mileage is used as the horizontal coordinate, within the set initial upper limit length of the vertical coordinate, the vertical coordinate 0m position is the 0m sinking position, and downward is the positive direction, that is, the sinking amount, and a surface settlement strike line sinking curve of the mining working face is drawn in the basic base map according to the horizontal and vertical ratio of 1:100 as a ground subsidence curve, wherein the ground subsidence curve is updated regularly according to the set period (for example, for real-time data, the ground subsidence curve can be updated daily as the mining working face advances for 1 day, and the ground subsidence curve can be updated once a month for data manually collected from the mining working face).

[0418] Optionally, the horizontal coordinate of the support pressure data is normalized, and the working face mining mileage is used as the horizontal coordinate, and within the set initial upper limit length of the vertical coordinate, a support pressure cloud map is drawn in the basic base map according to the third horizontal and vertical ratio, including: when the third horizontal and vertical ratio is 1:0.2, the horizontal coordinate of the support pressure data is normalized, and the working face mining mileage is used as the horizontal coordinate, and within the set initial upper limit length of the vertical coordinate, the support work cloud map is adjusted and drawn in the basic base map according to the horizontal and vertical ratio of 1:0.2, wherein the support work cloud map is regularly updated based on the advancement of the working face mining mileage (for example, the support work cloud map can be updated daily as the mining working face advances).

[0419] Optionally, the horizontal coordinates of the working face mining position and the pressure relief engineering quantity data are normalized, and the working face mining mileage is used as the horizontal coordinate, and within the set initial upper limit length of the vertical coordinate, a pressure relief engineering / mining position map is drawn in the basic base map according to the fourth horizontal-to-vertical ratio, including: when the fourth horizontal-to-vertical ratio is 1:0.2, the horizontal coordinates of the working face mining position and the pressure relief engineering quantity data are normalized, and the working face mining mileage is used as the horizontal coordinate, and within the set initial upper limit length of the vertical coordinate, the working face mining position and the pressure relief engineering quantity data are adjusted and drawn according to the horizontal-to-vertical ratio of 1:0.2 in the basic base map to obtain various pressure relief engineering projects and the current mining position, wherein the pressure relief engineering includes surface fracturing, downhole fracturing, downhole roof blasting, coal seam blasting or large-diameter drilling, and the pressure relief engineering / mining position map is also regularly updated based on the corresponding advancement mileage of the working face mining position (for example, the working face mining position and pressure relief engineering quantity data can be updated daily as the mining working face advances).

[0420] Optionally, the horizontal coordinates of the mining intensity data and the microseismic monitoring data are normalized, and the working face mining mileage is used as the horizontal coordinate, and within the set initial upper limit length of the vertical coordinate, a microseismic daily frequency / microseismic daily energy / daily mining footage trend chart is drawn in the basic base map according to the fifth horizontal and vertical ratio, including: normalizing the horizontal coordinate of the mining intensity data, and using the working face mining mileage as the horizontal coordinate, within the set initial upper limit length of the vertical coordinate, inputting the microseismic daily frequency, microseismic daily energy, and working face daily footage values ​​in the mining intensity data and microseismic monitoring data into the drawing software to form a microseismic daily frequency / microseismic daily energy / daily mining footage trend chart in the basic base map according to the fifth horizontal and vertical ratio, and the origin (0, 0) of the basic base map (CAD) is used as the origin coordinate of the microseismic daily frequency / microseismic daily energy (microseismic activity) / daily mining footage trend chart, wherein the microseismic daily frequency / microseismic daily energy / daily mining footage trend chart is also regularly updated based on the advancement of the working face mining mileage.

[0421] like Figure 22 As shown, step 104 is to analyze the rock characteristics of the roof, the pressure pattern of the cloud map, the ground subsidence, the mining intensity, the microseismic activity, the mining location and the completed pressure relief projects based on a graph for tracking and evaluating the effect of rock burst prevention and control, so as to predict the rock burst danger level of the mining face at different time periods.

[0422] In some possible implementations, by daily updating of information such as the roof lithology distribution map, ground settlement curve map, support pressure cloud map, pressure relief project / mining location map, microseismic daily frequency / microseismic daily energy / daily mining footage trend map, etc., the degree of rock burst hazard of the working face under the current situation where measures have been taken is analyzed, the anti-rock burst effect is tracked and analyzed, and the degree of rock burst hazard in the subsequent time is predicted based on a comprehensive assessment of the slate lithology characteristics, cloud map pressure patterns, ground settlement conditions, mining intensity, microseismic activity, mining location and completed pressure relief projects, thereby reducing the risk of rock burst.

[0423] The method for tracking and evaluating the effect of rock burst prevention and control of an embodiment of the present invention selects evaluation factors when rock burst occurs in a mining face; draws a basic base map of the mining face in a preset drawing software based on the mining map of the mining face; based on the evaluation factors, takes the mining mileage of the working face as the benchmark as the horizontal coordinate, sets the initial upper limit length of the vertical coordinate, and draws a roof lithology distribution map, a ground settlement curve map, a support pressure cloud map, a pressure relief project / mining location map, a microseismic daily frequency / microseismic daily energy / daily mining footage trend map in the basic base map according to different horizontal and vertical ratios, and assembles them into a map for tracking and evaluating the effect of rock burst prevention and control; analyzes and predicts the degree of rock burst danger of the mining face at different time periods. Thus, each evaluation factor is processed into a unified coordinate system based on the mining mileage, the horizontal coordinate is fixed, and the vertical coordinate ratio is optimized to achieve the timeliness and accuracy of tracking and evaluating the effect of rock burst prevention and control.

[0424] The present invention also proposes an example diagram of a tracking and evaluation diagram for rock burst prevention and control effects, such as Figure 23 As shown, a graph for tracking and evaluating the effect of rock burst prevention and control includes a roof lithology distribution graph, a ground settlement curve graph, a support pressure cloud graph, a pressure relief project / mining location graph, and a microseismic daily frequency / daily energy / daily mining footage trend graph. Specifically, with the mining mileage of the working face as the horizontal coordinate, the roof lithology distribution in the roof lithology distribution graph (horizontal: vertical = 1:1) can include medium-grained sandstone and multiple layers of fine-grained sandstone; the microseismic daily frequency / microseismic daily energy / daily mining footage trend graph (horizontal: vertical = 1:1) includes curve graphs of microseismic daily energy / wj, daily footage / m, and microseismic daily frequency on different dates (for example, odd days from 4-1 to 5-25); the support pressure cloud graph (horizontal: vertical = 1:0.2) can select a graph at the mining mileage of the working face of 1000m to 1300m; The process / mining position diagram (horizontal: vertical = 1:0.2) can take the mining position of the working face No. 3106 on May 31 (May 31 position) and the goaf of 3104, the return air lane of 3106 and the No. 1, No. 2, No. 4, No. 5 and No. 7 holes in the main transport lane of 3106 as examples (No. 1 hole, hole diameter 717m, layer 70m, No. 2 hole, hole diameter 690m, layer 55m, No. 7 hole, hole diameter 666m, layer 55m, No. 4 hole, hole diameter 672m, layer 55m, No. 5 hole, hole diameter 720m, layer 65m), as shown in the figure; the ground subsidence curve-strike (horizontal: vertical = 1:100) can select the curve of the ground subsidence at 1000m to 1300m from the working face mining cut (from the cut) as the ground subsidence curve diagram.

[0425] It should be noted that if Figure 24 As shown, this is a diagram of the overall implementation steps of the method for coordinated management of rock burst and mine earthquakes based on regional fracturing according to an embodiment of the present invention. Regarding step S6, the monitoring and evaluation of the regional fracturing pressure relief effect involved in this step do not have a fixed logical order with the preceding steps S1 to S5. That is, step S6 can be implemented independently or simultaneously with any of the preceding steps S1 to S5 to achieve the purpose of monitoring and evaluation. Similarly, step S7 can also be implemented independently or simultaneously with any of the preceding steps S1 to S6.

[0426] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0427] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0428] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0429] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0430] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0431] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for collaboratively controlling rock burst and mine tremors based on regional fracturing, characterized in that: The following steps are involved: S1. Based on 3D seismic exploration, drill core and microseismic positioning analysis, a stratigraphic model of the mining area is established and the working face is selected; By using the key layer theory, we first determine all the rock burst control layers within the fracture zone in the mining area stratigraphic model that have rock burst risks. Then, several mine earthquake control layers with mine earthquake risk above the fracture zone in the mine area stratigraphic model are determined; Furthermore, the key layers with rock burst risk and mine tremor risk within the caving zone and fracture zone are regarded as rock burst control layers; S2. Prioritize the analysis of the primary control layer for all rock burst control layers within the fracture zone. Develop a step-by-step determination and management analysis principle for all rock burst control layers. Eliminate other rock burst control layers that will not pose a rock burst risk after the current rock burst control layer is managed. Determine a multi-level primary rock burst control layer from all rock burst control layers. S3. Conduct a master control layer analysis on all mine earthquake control layers above the fracture zone, formulate a step-by-step determination and management analysis principle for the mine earthquake control layers, eliminate mine earthquake control layers that cannot produce disaster-causing effects after being managed, and determine multiple levels of mine earthquake master control layers from all mine earthquake control layers; S4. Perform well logging correction analysis and dynamically correct the positions of target rock layers of the multi-level rock burst main control layer and the multi-level mine earthquake main control layer; S5. Determine the layout design of layered fracturing based on the length and width of the working face, the thickness of the rock burst control layer, and the number of mine seismic control layers. The layered fracturing layout design includes: a combined fracturing method of surface vertical wells and underground horizontal wells, a fracturing method of surface multi-layer horizontal wells, a combined fracturing method of surface horizontal wells and surface vertical wells, and a fracturing method of surface vertical wells.

2. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 1, characterized in that: In step S1, when determining the rock burst control layer, the following steps are included: S111. Calculate the energy released by the breaking of the current key layer; S112, analyzing the energy measured by each sensor in historical rock burst cases in the current area to determine the vibration energy attenuation law; S113. Calculate the remaining energy transferred to the working face based on the energy released by the breaking of the key layer and the vibration energy attenuation law; S114. Based on the analysis of energy accumulation, transfer, release and dissipation after mining, a residual energy induced shock risk assessment system is established to determine the shock induction conditions, and the rock layer whose residual energy meets the shock induction conditions is determined as the rock burst control layer.

3. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 2, characterized in that: In step S1, when determining the mine earthquake control layer, the following steps are included: S121. Determine the mine earthquake control layer that has a mine earthquake disaster impact on the underground mining working face; Calculate the energy released by the breaking of the current key layer; and determine the vibration energy attenuation law by analyzing the actual energy measured by each sensor in historical mine earthquake cases in the current area. Based on the energy released by the breaking of the key layer and the vibration energy attenuation law, calculate the residual energy transmitted to the working face, and use the residual energy to assess the risk of mine earthquake induced shock. The rock layer whose residual energy meets the conditions for induced shock is determined as the mine earthquake control layer; S122. Determine the mine earthquake control layer that has a disaster-causing impact on the ground; Vibration velocity monitoring sensors are arranged on the ground to monitor the speed at which mine earthquakes are transmitted to the surface. The maximum vibration velocity of different rock strata is obtained through theoretical analysis. The mine earthquake intensity levels corresponding to different strata are determined based on the maximum vibration velocity of the rock strata at different strata. The mine earthquake control layer with a mine earthquake intensity level of II or above is determined as the mine earthquake control layer.

4. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 1, characterized in that: In step S2 and step S3, the principles for stepwise determination and control analysis of multiple rock burst control layers or multiple mine tremor control layers include: Compare the residual energies of multiple rock burst control layers or multiple mine seismic control layers, and use the rock burst control layer or mine seismic control layer with the largest residual energy transmitted to the working face as the primary rock burst main control layer or the primary mine seismic main control layer, and conduct a control analysis on the primary rock burst main control layer or the primary mine seismic control layer; Repeat step S1 to assess rock burst risk or mine tremor risk for other control layers adjacent to the controlled main control layer, eliminate rock burst control layers or mine tremor control layers that no longer have rock burst risk or mine tremor risk, and select rock burst control layers or mine tremor control layers adjacent to the controlled main control layer that still have induced rock burst risk or mine tremor risk as the next level of controlled disaster-causing main control layer; This step is repeated until there is no more risk of mine earthquake disaster or rock burst disaster in other key layers, thus forming a multi-level rock burst main control layer or a multi-level mine earthquake main control layer.

5. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 1, characterized in that: In steps S2 to S4, each level of rock burst main control layer or each level of mine earthquake main control layer is treated by fracturing or blasting; The mechanical properties of the rock burst main control layer or the mine earthquake main control layer after being controlled are weakened. During the control analysis, it is necessary to analyze the attenuation effect and structural regulation effect of the coordinated rock burst main control layer or the mine earthquake main control layer after being controlled, so as to eliminate the rock burst control layer or the mine earthquake control layer that no longer has rock burst risk or mine earthquake risk.

6. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 1, characterized in that: In steps S2 to S4, when there are multiple layers of thick hard roof in the mine, in the process of step-by-step determination and management analysis of the multi-level mine earthquake main control layer or the multi-level rock burst main control layer, the number of layers for fracturing management should be determined according to the position of the disaster-causing rock layer.

7. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 6, characterized in that: In step S5, determining the layout design of the layered fracturing further includes the following steps: Determine the mine geological conditions and fracturing construction parameters, estimate the expansion of the mine fracturing network, collect working face width information and strike length information, analyze the development of lateral mining-induced cracks in the working face, and estimate the construction length of surface vertical wells, underground horizontal wells, surface vertical wells, surface horizontal wells, and multi-layer horizontal wells.

8. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 6, characterized in that: In a working face with a width of less than 350m, the implementation of the combined well fracturing method of surface vertical wells and underground horizontal wells includes the following steps: According to the estimated fracturing information of the horizontal well and the fracturing range of the vertical well, the horizontal well construction information is determined, and the impact rock pressure control layer is fracturing constructed based on the horizontal well construction information. The underground horizontal well is located between the ground vertical well and the working face tunnel.

9. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 6, characterized in that: In a working face with a width greater than or equal to 350m, the implementation of the combined well fracturing method of surface vertical wells and underground horizontal wells includes the following steps: The horizontal well construction information is determined according to the estimated fracturing information of the horizontal well and the fracturing range of the vertical well, and the rock burst control layer is subjected to fracturing construction based on the horizontal well construction information. The downhole horizontal well is arranged between the ground vertical well and the tunnel of the working face; wherein, the vertical well construction information includes the number of the ground vertical wells, and the number of the ground vertical wells is multiple, and the multiple ground vertical wells are divided into at least two vertical well groups, and at least two of the vertical well groups are arranged at intervals along the inclination of the working face to be mined.

10. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 6, characterized in that: The implementation of the multi-layer horizontal well fracturing method further includes the following steps: A first well group and a second well group are arranged at intervals in the inclination direction of the working face, the first well group includes a first low-level horizontal well and a first high-level horizontal well arranged at intervals in the direction of the coal seam height, the second well group includes a second low-level horizontal well and a second high-level horizontal well arranged at intervals in the direction of the coal seam height, the extension direction of the fracture range formed by the fracturing of the first low-level horizontal well coincides with the extension direction of the fracture range formed by the fracturing of the second low-level horizontal well, the extension direction of the fracture range formed by the fracturing of the first high-level horizontal well coincides with the extension direction of the fracture range formed by the fracturing of the second high-level horizontal well, and the fracture range formed by the fracturing of the first low-level horizontal well is located below the fracture range formed by the fracturing of the first high-level horizontal well.

11. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 6, characterized in that: The implementation of the combined well fracturing method of surface horizontal wells and surface vertical wells further includes the following steps: A joint well group is constructed, wherein the joint well group includes a ground horizontal well and multiple vertical wells. Before excavation and mining at the first mining face, in the first mining face and the second mining face, horizontal wells are arranged in the coal pillar area between the first mining face and the second mining face and in one of the second mining faces, and fracturing operations are carried out. In the second mining face, multiple vertical wells are constructed along the direction of the mining face and fracturing operations are carried out. Alternatively, after the first mining face is excavated and mined, horizontal wells are arranged along the direction of the second working face and hydraulic fracturing is carried out. Multiple vertical wells are constructed along the direction of the working face and hydraulic fracturing is carried out. There are multiple combined well layout groups, and the multiple combined well layout groups are arranged in sequence along the inclination of the working face.

12. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to claim 6, characterized in that: In the rock burst control layer and the mine earthquake control layer, where the occurrence is unstable and the number of fracturing layers exceeds three, the construction of the surface vertical well fracturing method further includes the following steps: A plurality of ground vertical wells are arranged in sequence along the strike direction of the working face on the ground, and a staged fracturing process is used to implement fracturing on each thick hard roof plate. The method also includes a plurality of ground vertical well groups, one of which includes the plurality of ground vertical wells, and the plurality of ground vertical well groups are arranged at intervals along the dip direction of the working face.

13. The method for coordinated control of rock burst and mine earthquake based on regional fracturing according to any one of claims 1 to 12, characterized in that: The following steps are also included: S6. During the fracturing and production periods, monitor and evaluate the regional fracturing pressure relief effect to effectively guide the optimization of the regional fracturing plan; S7. Select evaluation factors when rock burst occurs at the mining face, draw a basic base map of the mining face in a preset drawing software, and compile a rock burst prevention and control effect tracking and evaluation map based on the collected relevant data. Based on the rock burst prevention and control effect tracking and evaluation map, analyze the roof lithologic characteristics, cloud pressure pattern, ground subsidence, completed pressure relief projects and mining intensity to predict the rock burst hazard level of the mining face at different time periods.

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