Method for treating a fault at the face cut

Abstract

The application provides a working face cut eye head-on fault processing method, comprising the following steps: obtaining related parameters of a hard rock fault in front of an extension direction of a working face cut eye and designing related parameters of a drill hole; determining a plurality of fracturing hole positions and a plurality of observation hole positions on the hard rock fault according to the determined related parameters of the drill hole, any one observation hole position is located between two adjacent fracturing hole positions, a plurality of hydraulic fracturing holes are drilled at the plurality of fracturing hole positions, and a plurality of fracturing observation holes are drilled at the plurality of observation hole positions; performing hydraulic fracturing processing on the hard rock fault; injecting fluid into the hydraulic fracturing holes, each hydraulic fracturing hole forms a hydraulic crack extending in a circumferential direction of the hydraulic fracturing hole under the action of the fluid, and the plurality of hydraulic cracks are interlaced in the hard rock fault; and performing cutting processing on the hard rock fault after hydraulic fracturing. By adopting the scheme, the problems of low efficiency, high cost and insecurity in the prior art for blasting processing of the hard rock fault can be solved.

Description

Technical Field

[0001] This invention relates to the field of working face cutting-head fault treatment technology, and more specifically, to a method for treating working face cutting-head faults. Background Technology

[0002] As the depth and scale of coal mining continue to increase, the geological conditions encountered at the coal mining face become increasingly complex. Geological structures such as faults are frequently encountered at the coal mining face. When the geological structure in the area has low strength or is broken, grouting reinforcement and support are usually required. However, when the geological structure such as faults at the coal mining face cut is relatively intact and has high strength, certain means and methods are usually required to pre-treat the hard fault geological structure in the area. On the one hand, this aims to reduce the strength of the rock in the fault area in advance, and on the other hand, it is conducive to the bottoming of the working face and the subsequent advancement of the working face.

[0003] Currently, the most common method is to use loosening blasting technology. This method first requires drilling numerous and densely packed boreholes, then filling the boreholes with explosives, and finally detonating the blast. The shockwave from the explosion breaks up the hard rock fault zone, increasing its shearability, and finally allowing a coal cutter to cut through the area. However, this method has the following drawbacks in practical engineering applications: 1) The entire loosening blasting operation must be carried out while the working face is suspended, requiring the evacuation of personnel, which severely impacts the normal progress of the working face; 2) The large number of boreholes required results in a significant workload, increasing labor and time costs; 3) The construction process is cumbersome and complex, requiring steps such as loading and blasting, and a large amount of explosives, leading to high economic costs; 4) The blasting process can easily damage surrounding equipment, and the release of toxic and harmful gases after blasting can negatively impact the health and well-being of workers. Summary of the Invention

[0004] This invention provides a method for treating the face fault at the working face, in order to solve the problems of low efficiency, high cost and safety in the existing technology of blasting treatment of hard rock faults.

[0005] To address the aforementioned problems, this invention provides a method for processing faults at the face of a working face, comprising: acquiring relevant parameters of the hard rock fault ahead of the working face's cut-out direction and designing relevant parameters for drilling; determining the locations of multiple fracturing holes and multiple observation holes on the hard rock fault based on the designed drilling parameters, wherein any observation hole location is located between two adjacent fracturing hole locations; drilling multiple hydraulic fracturing holes corresponding to the multiple fracturing hole locations and multiple fracturing observation holes corresponding to the multiple observation hole locations; performing hydraulic fracturing on the hard rock fault: injecting fluid into the hydraulic fracturing holes, each hydraulic fracturing hole forming a hydraulic crack extending circumferentially towards the hydraulic fracturing hole under the pressure of the fluid, with multiple hydraulic cracks intersecting within the hard rock fault; and cutting the hydraulically fractured hard rock fault.

[0006] Furthermore, at least one Z-shaped hydraulic fracturing hole is drilled at a portion of the fracturing hole locations using a drilling rig in the working face cut-out; multiple L-shaped hydraulic fracturing holes are drilled at another portion of the fracturing hole locations using a drilling rig in the working face cut-out. The multiple L-shaped hydraulic fracturing holes are arranged in pairs at intervals and parallel to each other. The Z-shaped hydraulic fracturing holes are inclined relative to the L-shaped hydraulic fracturing holes. The fracturing observation holes are L-shaped fracturing observation holes, and the L-shaped fracturing observation holes are parallel to the L-shaped hydraulic fracturing holes. Any L-shaped fracturing observation hole is located between two adjacent L-shaped hydraulic fracturing holes.

[0007] Furthermore, the locations of multiple fracturing holes and multiple observation holes are spaced apart in both the height and horizontal directions. The projections of the L-shaped hydraulic fracturing holes and L-shaped fracturing observation holes on the bottom plate of the working face cut are parallel, while the projections of the Z-shaped hydraulic fracturing holes on the bottom plate of the working face cut are inclined relative to the L-shaped hydraulic fracturing holes and pass through multiple L-shaped fracturing observation holes.

[0008] Furthermore, the diameters of the L-type hydraulic fracturing holes, L-type fracturing observation holes, and Z-type hydraulic fracturing holes are all 56–65 mm, the drilling depths are all 35–55 m, and the distance between any fracturing hole location and its adjacent observation hole location, or between any fracturing hole location, is 3–7 m.

[0009] Furthermore, the method for hydraulic fracturing hard rock faults includes: using a "dual-sealing" perforator that integrates perforation sealing and fracturing to perform backward fracturing on each L-type and Z-type hydraulic fracturing hole. Each L-type or Z-type hydraulic fracturing hole has multiple fracturing positions extending along its axial direction. Hydraulic cracks are generated at the fracturing positions under the action of fluid pressure. The distance between two adjacent fracturing positions in the same hydraulic fracturing hole is 1.8 to 2.2 m.

[0010] Furthermore, the inclination angle of the L-shaped hydraulic fracturing hole relative to the bottom plate of the working face cut is 3 to 5 degrees.

[0011] Furthermore, the minimum distance between any fracturing hole location and any observation hole location and the bottom plate of the working face cut shall not be less than 1.5m.

[0012] Furthermore, the method for handling the face-cutting fault also includes: determining whether there is an excessively hard fault that cannot be hydraulically fractured in the hard rock fault after hydraulic fracturing during the cutting process; if there is no excessively hard fault, cutting the hard rock fault after hydraulic fracturing; if there is an excessively hard fault, cutting the part of the hard rock fault after hydraulic fracturing that does not contain the excessively hard fault, and fracturing the excessively hard fault within the hard rock fault through a static fracturing treatment method.

[0013] Furthermore, the static fracturing treatment method includes: drilling multiple fracturing holes in the hard fault, with the extension directions of the multiple fracturing holes being parallel; placing a fracturing explosive cartridge into each fracturing hole and compacting it; sealing the opening of each fracturing hole with a sealing material; and fracturing the fracturing holes for a fracturing time of not less than 24 hours.

[0014] Furthermore, the multiple fracturing holes are arranged in a multi-row manner, with the distance between two adjacent rows of fracturing holes being 300-500 mm, the distance between two adjacent fracturing holes in the same row being 300-350 mm, and the diameter of any fracturing hole being 36-50 mm.

[0015] Furthermore, the relevant parameters of hard rock faults include: the stress state, mechanical parameters, and distribution patterns of hard rock faults; the relevant parameters of boreholes include: borehole diameter, length, spacing, strike angle, dip angle, and number of boreholes.

[0016] The present invention provides a method for treating a fault at the face of a working face, characterized by comprising: acquiring relevant parameters of the hard rock fault in front of the working face's cut-out direction and designing relevant parameters for drilling; determining the locations of multiple fracturing holes and multiple observation holes on the hard rock fault based on the determined drilling parameters, wherein any observation hole location is located between two adjacent fracturing hole locations; drilling multiple hydraulic fracturing holes corresponding to the multiple fracturing hole locations and multiple fracturing observation holes corresponding to the multiple observation hole locations; performing hydraulic fracturing treatment on the hard rock fault: injecting fluid into the hydraulic fracturing holes, each hydraulic fracturing hole forming a hydraulic crack extending circumferentially towards the hydraulic fracturing hole under the pressure of the fluid, with multiple hydraulic cracks intersecting within the hard rock fault; and cutting the hydraulically fractured hard rock fault. This approach utilizes hydraulic fracturing to treat the hard rock fault ahead of the working face, enabling pretreatment of the fault without disrupting normal coal mining operations. This avoids the need for blasting in existing technologies, which requires the working face to be shut down, thus ensuring normal working face advancement efficiency. Furthermore, hydraulic fracturing of hard rock faults requires fewer and deeper fracturing holes, avoiding the need for numerous drilling operations and complex procedures common in blasting, simplifying the process and reducing costs. Moreover, hydraulic fracturing of hard rock faults does not generate significant vibrations or produce toxic gases, avoiding the potential damage to surrounding equipment or the release of toxic gases associated with blasting in existing technologies, ensuring the safety of both the hard rock fault treatment process and the workers. During hydraulic fracturing, hydraulic cracks in the fracturing holes are observed through fracturing observation holes, and adjustments are made in a timely manner based on the observation results to ensure the reliability of hydraulic fracturing. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 A flowchart illustrating the method for processing the working face cutting edge fault provided by an embodiment of the present invention is shown.

[0019] Figure 2 It shows Figure 1 A schematic diagram illustrating the application of methods for handling faults at the working face cut-off point;

[0020] Figure 3 It shows Figure 2 A structural diagram from another perspective;

[0021] Figure 4 It shows Figure 2 Cross-sectional view of a Z-type hydraulic fracturing borehole;

[0022] Figure 5 It shows Figure 2 A cross-sectional view of an L-shaped hydraulic fracturing borehole;

[0023] Figure 6 It shows Figure 1 A schematic diagram illustrating the application of static fracturing treatment methods in the treatment of faults at the working face cut-off point;

[0024] Figure 7 It shows Figure 6 A sectional view.

[0025] The above figures include the following reference numerals:

[0026] 10. Working face cut-out; 20. Hard rock fault; 31. L-type hydraulic fracturing hole; 32. Z-type hydraulic fracturing hole; 33. L-type fracturing observation hole; 34. Hydraulic crack; 40. Overly hard fault; 51. Fracturing hole; 52. Fracturing explosive cartridge; 53. Sealing material. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] like Figures 1 to 7 As shown, an embodiment of the present invention provides a method for processing a working face cut-off fault, comprising: obtaining relevant parameters of a hard rock fault 20 in front of the working face cut-off 10 and designing relevant parameters for drilling; determining the locations of multiple fracturing holes and multiple observation holes on the hard rock fault 20 according to the designed relevant parameters for drilling, wherein any observation hole location is located between two adjacent fracturing hole locations, and multiple hydraulic fracturing holes are drilled corresponding to the multiple fracturing hole locations, and multiple fracturing observation holes are drilled corresponding to the multiple observation hole locations; performing hydraulic fracturing treatment on the hard rock fault 20: injecting fluid into the hydraulic fracturing holes, and forming hydraulic cracks 34 extending circumferentially towards each hydraulic fracturing hole under the pressure of the fluid, with multiple hydraulic cracks 34 intersecting each other within the hard rock fault 20; and cutting the hydraulically fractured hard rock fault 20.

[0029] In this embodiment, hydraulic fracturing is used to treat the hard rock fault 20 in front of the working face cut-in 10. This allows for the pretreatment of the hard rock fault 20 without affecting the normal coal mining process. It avoids the situation in existing technologies where blasting to treat the hard rock fault 20 requires the working face to be suspended, thus ensuring the normal advancing efficiency of the working face. Furthermore, hydraulic fracturing of the hard rock fault 20 requires fewer hydraulic fracturing holes and a longer depth, avoiding the need for numerous drilling holes and complex construction procedures as in existing technologies using blasting. This simplifies the construction process and reduces costs. Moreover, hydraulic fracturing of the hard rock fault 20 does not generate significant vibrations or produce any toxic or harmful gases, avoiding the damage to surrounding equipment or the production of toxic or harmful gases that can occur with blasting in existing technologies. This ensures the safety of the hard rock fault 20 treatment process and the safety of the workers. During hydraulic fracturing, the hydraulic cracks 34 in the hydraulic fracturing hole are observed through the fracturing observation hole, and timely adjustments are made based on the observation results to ensure the reliability of hydraulic fracturing.

[0030] Optionally, the number of hydraulic fracturing locations is a, and the number of fracturing observation locations is b, where ab≥2.

[0031] like Figure 2 and Figure 3 As shown, at least one Z-shaped hydraulic fracturing hole 32 is drilled at one part of the fracturing hole locations using a drilling rig in the working face cut-out 10; multiple L-shaped hydraulic fracturing holes 31 are drilled at another part of the fracturing hole locations using the same drilling rig in the working face cut-out 10. The multiple L-shaped hydraulic fracturing holes 31 are arranged in pairs, spaced apart and parallel to each other. The Z-shaped hydraulic fracturing holes 32 are inclined relative to the L-shaped hydraulic fracturing holes 31. The fracturing observation holes are L-shaped fracturing observation holes 33, which are parallel to the L-shaped hydraulic fracturing holes 31. Any L-shaped fracturing observation hole 33 is located between two adjacent L-shaped hydraulic fracturing holes 31. This arrangement enables complete fracturing of the hard rock fault 20 in both the horizontal and vertical directions through the L-shaped and Z-shaped hydraulic fracturing holes, ensuring the reliability and completeness of the fracturing. The hydraulic cracks 34 formed by the L-shaped hydraulic fracturing holes 31 are observed by setting L-shaped fracturing observation holes 33 between any two adjacent L-shaped hydraulic fracturing holes 31, ensuring the reliability of hydraulic fracturing. Specifically, in this embodiment, there is one Z-shaped hydraulic fracturing hole 32, three L-shaped hydraulic fracturing holes 31, and two L-shaped fracturing observation holes. Further, the L-shaped hydraulic fracturing hole 31 is a hydraulic fracturing hole whose axis extension direction is parallel to the extension direction of the working face cut 10, and the Z-shaped hydraulic fracturing hole 32 is a hydraulic fracturing hole whose axis extension direction is inclined relative to the extension direction of the working face cut 10.

[0032] Furthermore, the locations of multiple fracturing holes and multiple observation holes are spaced apart in both the vertical and horizontal directions. The projections of L-shaped hydraulic fracturing holes 31 and L-shaped fracturing observation holes 33 onto the bottom plate of the working face cut-in 10 are parallel, while the projection of Z-shaped hydraulic fracturing holes 32 onto the bottom plate of the working face cut-in 10 is inclined relative to the L-shaped hydraulic fracturing holes 31 and passes through multiple L-shaped fracturing observation holes 33. This arrangement ensures the fracturing effect on the hard rock fault 20 in the extension direction of the working face cut-in 10 through the L-shaped hydraulic fracturing holes 31, and ensures the fracturing effect on the hard rock fault 20 in the direction perpendicular to the extension direction of the working face cut-in 10 through the Z-shaped hydraulic fracturing holes 32, thus guaranteeing the completeness and reliability of fracturing.

[0033] Specifically, the diameters of L-type hydraulic fracturing holes 31, L-type fracturing observation holes 33, and Z-type hydraulic fracturing holes 32 are all 56–65 mm, and the drilling depths are all 35–55 m. The distance between any fracturing hole location and its adjacent observation hole location, or between any fracturing hole location, is 3–7 m. This setting, by limiting the distance between fracturing hole locations and adjacent fracturing hole locations or observation hole locations, ensures the reliability of hydraulic fracturing and avoids the situation where the distance between two adjacent hydraulic fracturing holes is too close, requiring more hydraulic fracturing holes for hydraulic fracturing of the same size hard rock fault 20, which would increase the processing cost and processing time of hydraulic fracturing holes. At the same time, it avoids the situation where the distance between two adjacent hydraulic fracturing holes is too far, resulting in a large distance between the hydraulic cracks and a reduced fracturing effect. By limiting the diameter and depth of the hydraulic fracturing holes and fracturing observation holes, the reliability and completeness of hydraulic fracturing within the aforementioned spacing limits are ensured, thereby guaranteeing the fracturing effect.

[0034] In this embodiment, the method for hydraulic fracturing the hard rock fault 20 includes: using a "dual-sealing" perforator that integrates perforation sealing and fracturing to perform backward fracturing on each L-shaped hydraulic fracturing hole 31 and Z-shaped hydraulic fracturing hole 32. Each L-shaped or Z-shaped hydraulic fracturing hole 31 has multiple fracturing positions extending along its axial direction. Under the action of fluid pressure, hydraulic cracks 34 are generated at the fracturing positions. The distance between two adjacent fracturing positions in the same hydraulic fracturing hole is 1.8 to 2.2 m. This setting, by limiting the distance between two adjacent fracturing positions, ensures the fracturing effect of a hydraulic fracturing hole, thereby ensuring the reliability of hydraulic fracturing of the hard rock fault 20 by all hydraulic fracturing holes. Specifically, each fracturing position can form multiple hydraulic cracks 34 extending outward from the axis of the hydraulic fracturing hole and distributed circumferentially along the hydraulic fracturing hole.

[0035] like Figure 5As shown, the inclination angle of the L-shaped hydraulic fracturing borehole 31 relative to the bottom plate of the working face cut 10 is 3-5°. This setting ensures the reliability of the L-shaped hydraulic fracturing borehole 31 in fracturing the hard rock fault 20 in the vertical direction, and avoids the situation where the horizontal extension of the L-shaped hydraulic fracturing borehole leads to the appearance of upper and lower faults in the hard rock fault 20 after hydraulic fracturing, but the upper and lower faults are not completely fractured, thus ensuring the completeness of hydraulic fracturing. In this embodiment, the inclination angle is 3°.

[0036] Specifically, L-shaped hydraulic fracturing holes 31 extend upward and forward at an angle from one end of the hard rock fault 20 to the other end, and multiple L-shaped hydraulic fracturing holes 31 are spaced apart along the length of one end of the hard rock fault 20. Z-shaped hydraulic fracturing holes 32 extend horizontally from one side of one end of the hard rock fault 20 to the other side. This can also be understood as the plane containing the multiple L-shaped hydraulic fracturing holes 31 being inclined upward relative to the bottom plate of the working face cut-out 10, and the plane containing the Z-shaped hydraulic fracturing holes 32 being parallel to the bottom plate of the working face cut-out 10 and located below the plane containing the multiple L-shaped hydraulic fracturing holes 31. The hydraulic cracks 34 formed by the L-shaped hydraulic fracturing hole 31 are inclined from bottom to top and distributed at intervals. The hydraulic cracks 34 formed by the Z-shaped hydraulic fracturing hole 32 are distributed at intervals in the horizontal direction. The hydraulic fracturing above the rear side of the hard rock fault 20 is achieved by the hydraulic cracks 34 formed by the L-shaped hydraulic fracturing hole 31. The hydraulic fracturing below the rear side of the hard rock fault 20 is achieved by the hydraulic cracks 34 formed by the Z-shaped hydraulic fracturing hole 32. The middle area of ​​the rear side of the hard rock fault 20 is achieved by the combined hydraulic cracks 34 formed by the L-shaped hydraulic fracturing hole 31 and the Z-shaped hydraulic fracturing hole 32. By combining the above-mentioned setup of L-type hydraulic fracturing holes 31 and Z-type hydraulic fracturing holes 32, the hydraulic cracks 34 between two adjacent L-type hydraulic fracturing holes 31 are alternately set. Combined with the staggered setup of Z-type hydraulic fracturing holes and L-type hydraulic fracturing holes 31 in the height direction, the completeness of hydraulic fracturing of hard rock fault 20 by L-type hydraulic fracturing holes 31 is guaranteed.

[0037] like Figure 4 and Figure 5 As shown, the minimum distance between any fracturing hole location and any observation hole location and the bottom plate of the working face cut 10 is not less than 1.5m. This setting ensures that the hydraulic fracturing holes will not be too close to the ground during the fracturing process, which would cause the hydraulic cracks 34 to directly fracture the underlying hard rock fault 20, resulting in incomplete hydraulic fracturing of the underlying hard rock fault. This ensures the completeness and reliability of the hydraulic fracturing of the hard rock fault 20.

[0038] like Figure 6 and Figure 7As shown, the method for handling the fault at the working face cut also includes: during the cutting process, determining whether there is an excessively hard fault 40 in the hydraulically fractured hard rock fault 20 that cannot be hydraulically fractured; if there is no excessively hard fault 40, cutting the hydraulically fractured hard rock fault 20; if there is an excessively hard fault 40, cutting the portion of the hydraulically fractured hard rock fault 20 that does not contain the excessively hard fault 40, and fracturing the excessively hard fault 40 within the hard rock fault 20 using a static fracturing method. This setup ensures the reliability of the hard rock fault 20 treatment by fracturing and cutting the excessively hard fault 40 within the hard rock fault 20 that cannot be hydraulically fractured using a static fracturing method.

[0039] Specifically, the static fracturing method includes: drilling multiple fracturing holes 51 in the hard fault 40, with the extension directions of the multiple fracturing holes 51 parallel; placing a fracturing explosive cartridge 52 into each fracturing hole 51 and compacting it; sealing the opening of each fracturing hole 51 with a sealing material 53; and fracturing the fracturing holes 51 for a fracturing time of not less than 24 hours. This setup, by using multiple fracturing holes 51, ensures the completeness of fracturing the hard fault 40 and guarantees the fracturing effect of the static fracturing method. The use of fracturing explosive cartridges to fracture the fracturing holes 51 ensures the stability of the fracturing process using the static fracturing method. The sealing material 53 is used to seal the openings of the fracturing holes 51, preventing some rock fragments from ejecting from the fracturing holes 51 during the fracturing process and improving the safety of the static fracturing method. Specifically, the sealing material 53 is yellow clay, etc.

[0040] Furthermore, the multiple fracturing holes 51 are arranged in multiple rows, with the distance between two adjacent rows of fracturing holes 51 being 300–500 mm, and the distance between two adjacent fracturing holes 51 within the same row being 300–350 mm. The diameter of any single fracturing hole 51 is 36–50 mm. This arrangement limits the distance between adjacent rows of fracturing holes 51, avoiding the situation where adjacent rows of fracturing holes 51 are too close together, requiring more rows of fracturing holes 51 to achieve fracturing, thus increasing the processing cost and time of the fracturing holes 51. At the same time, it avoids the situation where adjacent rows of fracturing holes 51 are too far apart, making it difficult to fracture the overly hard fault 40 in the middle of the area between adjacent rows of fracturing holes 51, thus ensuring the fracturing effect of each row of fracturing holes 51. The distance between two adjacent fracturing holes 51 in the same row is limited to avoid the situation where two adjacent fracturing holes 51 are too close together, requiring a large number of fracturing holes 51 in the same row to achieve fracturing, which would increase the processing cost and time of the fracturing holes 51. At the same time, it avoids the situation where two adjacent fracturing holes 51 are too far apart, making it difficult to fracture the overly hard fault 40 in the middle position between the two fracturing holes 51, thus ensuring the fracturing effect of multiple fracturing holes 51 in the same row. The diameter of the fracturing holes 51 is limited to ensure that the fracturing effect of fracturing holes 51 within the above-mentioned distance range is achieved within the range of diameters.

[0041] Specifically, the arrangement of the fracture-inducing holes 51 is generally in the form of five or three holes. In this embodiment, the arrangement is a five-hole arrangement, that is, three rows are arranged, and the fracture-inducing holes 51 in adjacent rows are spaced apart in the horizontal direction. This ensures that the multiple fracture-inducing holes 51 can effectively fracture the hard fault 40 and avoids the situation where there is still a large-sized hard fault 40 after fracture, thus ensuring the reliability of static fracture induction.

[0042] In this embodiment, the relevant parameters of the hard rock fault 20 include: the stress state, mechanical parameters, and distribution law of the hard rock fault 20; the relevant parameters of the boreholes include: borehole diameter, length, spacing, strike angle, dip angle, and number. In this embodiment, the various parameters of the hard rock fault are mainly tested through indoor mechanical parameter testing. The stress distribution state in front of the working face cut is analyzed by combining theoretical calculation and numerical simulation, which serves as the theoretical basis for the design of various parameters of subsequent hydraulic fracturing boreholes to ensure the reliability of hydraulic fracturing. Specifically, according to the designed borehole strike angle, the hydraulic fracturing boreholes are divided into L-type hydraulic fracturing boreholes and Z-type hydraulic fracturing boreholes. The strike angle is the angle between the extension direction of the borehole and the forward extension direction of the working face cut.

[0043] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0044] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0045] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0046] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0047] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for treating the fault at the face of a working face, characterized in that, include: Obtain relevant parameters of the hard rock fault (20) in front of the working face cut (10) extension direction and design relevant parameters of the borehole; Based on the relevant parameters of the designed borehole, determine the locations of multiple fracturing holes and multiple observation holes on the hard rock fault (20). Any one of the observation holes is located between two adjacent fracturing hole locations. Multiple hydraulic fracturing holes are drilled at the multiple fracturing hole locations, and multiple fracturing observation holes are drilled at the multiple observation hole locations. Hydraulic fracturing is performed on the hard rock fault (20): fluid is injected into the hydraulic fracturing holes, and each hydraulic fracturing hole forms a hydraulic crack (34) extending circumferentially to the hydraulic fracturing hole under the pressure of the fluid. Multiple hydraulic cracks (34) intersect each other in the hard rock fault (20). The hard rock fault (20) after hydraulic fracturing is cut; During the cutting process, it is determined whether there is an overly hard fault (40) that cannot be hydraulically fractured after hydraulic fracturing of the hard rock fault (20). If the hard rock fault (40) does not exist, cut the hard rock fault (20) after hydraulic fracturing; if the hard rock fault (40) exists, cut the part of the hard rock fault (20) after hydraulic fracturing that does not contain the hard rock fault (40), and fracture the hard rock fault (40) within the hard rock fault (20) by static fracturing treatment.

2. The method for treating the face-cutting fault according to claim 1, characterized in that, At least one Z-shaped hydraulic fracturing hole (32) is drilled in a portion of the fracturing hole locations using a drilling rig in the working face cut (10); multiple L-shaped hydraulic fracturing holes (31) are drilled in another portion of the fracturing hole locations using a drilling rig in the working face cut (10). The multiple L-shaped hydraulic fracturing holes (31) are arranged in pairs and parallel to each other. The Z-shaped hydraulic fracturing holes (32) are inclined relative to the L-shaped hydraulic fracturing holes (31). The fracturing observation hole is an L-shaped fracturing observation hole (33). The L-shaped fracturing observation hole (33) is parallel to the L-shaped hydraulic fracturing holes (31). Any one of the L-shaped fracturing observation holes (33) is located between two adjacent L-shaped hydraulic fracturing holes (31).

3. The method for treating the face-cutting fault according to claim 2, characterized in that, The locations of the multiple fracturing holes and the multiple observation holes are spaced apart in both the height and horizontal directions. The projections of the L-shaped hydraulic fracturing hole (31) and the L-shaped fracturing observation hole (33) on the bottom plate of the working face cut (10) are parallel. The projection of the Z-shaped hydraulic fracturing hole (32) on the bottom plate of the working face cut (10) is inclined relative to the L-shaped hydraulic fracturing hole (31) and passes through the multiple L-shaped fracturing observation holes (33).

4. The method for treating the face-cutting fault according to claim 2, characterized in that, The diameter of the L-shaped hydraulic fracturing hole (31), the L-shaped fracturing observation hole (33), and the Z-shaped hydraulic fracturing hole (32) are all 56~65mm, and the drilling depth is all 35~55m. The distance between any fracturing hole location and the adjacent observation hole location, or between any fracturing hole location, is 3~7m.

5. The method for treating the face-cutting fault according to claim 2, characterized in that, The method for hydraulic fracturing the hard rock fault (20) includes: using a "double-sealing" sealing device that integrates sealing and fracturing to perform backward fracturing on each of the L-type hydraulic fracturing holes (31) and the Z-type hydraulic fracturing holes (32). Each of the L-type hydraulic fracturing holes (31) or the Z-type hydraulic fracturing holes (32) has multiple fracturing positions extending along its axial direction. The fracturing positions generate hydraulic cracks (34) under the action of fluid pressure. The distance between two adjacent fracturing positions in the same hydraulic fracturing hole is 1.8~2.2m.

6. The method for treating the face-end fault according to claim 2, characterized in that, The inclination angle of the L-shaped hydraulic fracturing hole (31) relative to the bottom plate of the working face cut (10) is 3~5°.

7. The method for treating the face-end fault according to claim 1, characterized in that, The minimum distance between any of the fracturing holes and any of the observation holes and the bottom plate of the working face cut (10) shall not be less than 1.5m.

8. The method for treating the face-end fault according to claim 1, characterized in that, The static fracturing treatment method includes: Multiple fracture holes (51) are drilled in the hard fault (40), and the multiple fracture holes (51) extend in parallel directions; A rupture cartridge (52) is placed in each of the rupture holes (51) and pressed tightly. The opening of each of the rupture holes (51) is sealed with a sealing material (53). The fracturing hole (51) is fractured, and the fracturing time is not less than 24 hours.

9. The method for treating the face-end fault according to claim 8, characterized in that, The multiple fracturing holes (51) are arranged in a multi-row arrangement. The distance between two adjacent rows of fracturing holes (51) is 300~500mm. The distance between two adjacent fracturing holes (51) in the same row is 300~350mm. The diameter of any fracturing hole (51) is 36~50mm.

10. The method for treating the face-end fault according to claim 1, characterized in that, The relevant parameters of the hard rock fault (20) include: the stress state, mechanical parameters and distribution law of the hard rock fault (20); the relevant parameters of the borehole include: the diameter, length, spacing, strike angle, dip angle and number of the borehole.

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