Hole protecting device and method for gas extraction drill hole

Abstract

The invention relates to the technical field of coal mine gas extraction, and discloses a hole protecting device and method for a gas extraction drill hole. The hole protection device for the gas extraction drill hole comprises a first hole protection section and a second hole protection section, the first hole protection section comprises a first pipeline, an air bag assembly and a foldable suspension structure, and the suspension structure and the air bag assembly are both arranged on the outer wall of the first pipeline; the guide structure is arranged outside the first hole protection section in a sleeving mode so as to restrain the suspension structure and enable the suspension structure to be stored in the guide structure, and under the condition that the guide structure moves and exposes the suspension structure, the suspension structure is unfolded and clamped on the inner wall of a hole; the inflating device is communicated with the air bag assembly and used for inflating the air bag assembly, so that the air bag assembly is attached to the inner wall of the hole, and the hole is supported. In this way, a three-dimensional supporting system is formed by radial supporting force generated by expansion of the air bag assembly and axial anchoring of the suspension structure, and the hole collapse resistance of the soft coal seam is remarkably improved.

Description

Technical Field

[0001] This application relates to the field of coal mine gas drainage technology, for example to a borehole protection device and method for gas drainage boreholes. Background Technology

[0002] Soft coal seams have a loose coal body structure and extremely low strength. After drilling, the stress balance of the original coal seam is disrupted, and the radial stress decreases sharply from the borehole wall to the depth, forming obvious fracture zones and plastic zones. During stress release, the coal body is prone to collapse due to its own weight and deformation pressure. According to field statistics, the collapse rate of boreholes in this type of coal seam is as high as 60% within 24 hours after drilling. This can lead to blockage of the drainage pipeline or even borehole abandonment, requiring repeated drilling and significantly increasing operating costs. At the same time, the coal dust generated by the collapse can block the gas seepage channels, causing the drainage concentration to drop sharply from the initial 30% to 40% to below 10%, resulting in a 3 to 5-fold increase in the drainage cycle.

[0003] The relevant technology uses screen pipes (PVC perforated pipes, steel pipe screen pipes). To facilitate drilling, the screen pipe diameter needs to be 5 mm to 10 mm smaller than the borehole diameter, which results in an annular gap between the screen pipe and the borehole wall. This gap not only fails to prevent coal seam collapse but also becomes a major channel for gas escape. Furthermore, the screen pipe is a homogeneous rigid structure, unable to adapt to dynamic deformation of the coal seam. When the coal seam is compressed, the screen pipe is prone to breakage due to excessive local stress, further exacerbating the risk of borehole collapse.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0006] This disclosure provides a borehole protection device and method for gas drainage boreholes to improve borehole support capabilities.

[0007] In some embodiments, a borehole protection device for gas extraction boreholes includes: a first borehole protection section, comprising: a first pipe, an airbag assembly, and a retractable suspension structure, wherein the suspension structure and the airbag assembly are both disposed on the outer wall of the first pipe; a guide structure, sleeved on the first borehole protection section, for constraining the suspension structure, such that the suspension structure is retracted within the guide structure, and, when the guide structure moves and exposes the suspension structure, the suspension structure unfolds and engages with the inner wall of the borehole; and an inflation device, connected to the airbag assembly, for inflating the airbag assembly to make the airbag assembly fit against the inner wall of the borehole and support the borehole.

[0008] In some embodiments, the suspension structure includes: a plurality of snap-fit ​​structures disposed on the outer wall of the first pipe along the circumference of the first pipe.

[0009] In some embodiments, the snap-fit ​​structure includes: a connecting shaft, wherein the outer wall of the first pipe is provided with a first groove, and the connecting shaft is rotatably disposed in the first groove; a spring, disposed in the first groove, and the first end of the spring is connected to the inner wall of the first groove; and a pawl, wherein the first end of the pawl is connected to the connecting shaft and the second end of the spring, and the second end of the pawl is used to snap onto the inner wall of the hole.

[0010] In some embodiments, the airbag assembly includes: a plurality of airbags, a plurality of second grooves are provided on the outer wall of the first pipe, and each second groove is correspondingly disposed to each of the airbags; wherein, when the airbag is not inflated, the airbag is placed in the corresponding second groove.

[0011] In some embodiments, there are multiple first protective hole segments, and two adjacent first protective hole segments are connected by a tenon and mortise structure.

[0012] In some embodiments, the borehole protection device for a gas extraction borehole further includes: a second borehole protection section connected to the first borehole protection section; wherein the second borehole protection section includes a second pipe with seepage holes provided on its outer wall.

[0013] In some embodiments, there are multiple first hole segments and multiple second hole segments; the first hole segments and the second hole segments are alternately connected as a whole.

[0014] In some embodiments, the guide structure includes: a drill rod sleeved outside the first hole protector section; and an openable / closable drill bit connected to one end of the drill rod, wherein the outer diameter of the drill bit is adapted to the inner diameter of the hole; wherein, when support for the hole is required, the first hole protector section is pushed into the drill rod, and when the guide structure is retracted, the first hole protector section pushes the drill bit open to push the first hole protector section out of the drill bit.

[0015] In some embodiments, a method for protecting a gas extraction borehole is applied to the aforementioned device for protecting a gas extraction borehole. The method includes: pushing a guide structure into a predetermined depth in the borehole; pushing a first protective section into the top of the guide structure; retracting the guide structure so that the first protective section pushes open the guide structure and exposes it outside the guide structure, wherein the suspension structure of the first protective section is engaged with the inner wall of the borehole after losing the constraint of the guide structure; and inflating the air bladder of the first protective section so that the air bladder fits against the inner wall of the borehole, thereby supporting the borehole.

[0016] In some embodiments, a method for protecting a gas extraction borehole is applied to the aforementioned borehole protection device for a gas extraction borehole. The borehole protection device further includes: a second borehole protection section, the second borehole protection section being provided with seepage holes for gas seepage, and there are multiple first and second borehole protection sections. The method includes: pushing a guide structure into the borehole to a preset depth; sequentially pushing each of the first and second borehole protection sections into the guide structure according to a preset arrangement order, and connecting each section to form a whole; withdrawing the guide structure so that the connected whole pushes open the guide structure and exposes the outside of the guide structure; continuing to withdraw the guide structure section by section, so that the suspension structure of each first borehole protection section, after losing the constraint of the guide structure, is locked onto the inner wall of the borehole, and inflating the air bladder of the corresponding first borehole protection section, so that the air bladder of each first borehole protection section fits against the inner wall of the borehole section by section, thereby supporting the borehole.

[0017] The borehole protection device and method for gas drainage drilling provided in this disclosure can achieve the following technical effects: The guide structure is fitted outside the first borehole section. On one hand, it guides the first borehole section along the central axis of the borehole. On the other hand, the guide structure constrains the suspension structure within it. When the guide structure is retracted, the suspension structure is exposed and unconstrained, then unfolds and engages with the borehole wall, providing initial axial anchoring for the borehole protection device. The inflation device is connected to the airbag assembly. After the suspension structure is engaged with the borehole wall, the inflation device is activated to inflate the airbag assembly, causing it to expand radially along the borehole. Once the airbag assembly is tightly fitted to the borehole wall, it provides support for the borehole. Thus, the dual dynamic support of the suspension structure and the expanding airbag assembly forms a three-dimensional support system, significantly improving the borehole's resistance to collapse in soft coal seams. The initial anchoring of the suspension structure and the subsequent expansion of the airbag assembly create a progressively advancing support process, enhancing the overall support strength.

[0018] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Attached Figure Description

[0019] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 This is a schematic diagram of the structure of a borehole protection device for gas extraction boreholes provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of the guide structure located inside the hole according to an embodiment of the present disclosure; Figure 3 This is a schematic diagram of the structure of the first and second protective hole sections located within the guide structure according to an embodiment of this disclosure; Figure 4 This is a schematic diagram of the first protective hole section ejection guide structure provided in an embodiment of this disclosure; Figure 5 This is a schematic diagram of the structure after the airbag of the first protective hole section is inflated, according to an embodiment of this disclosure; Figure 6 This is a schematic diagram of the structure of the first protective hole section provided in an embodiment of this disclosure; Figure 7 This is a schematic diagram of the unfolded suspension structure of the first protective hole section provided in the embodiment of this disclosure; Figure 8 This is a schematic diagram of the structure of the airbag of the first protective hole section after inflation, provided in an embodiment of this disclosure; Figure 9 This is a schematic diagram of the protruding second protective hole section of the mortise and tenon structure provided in the embodiments of this disclosure; Figure 10 This is a schematic diagram of the second protective hole section with an outwardly protruding and inwardly recessed tenon and mortise structure provided in the embodiments of this disclosure; Figure 11 This is a schematic diagram of the closed structure of the center vane of a drill bit from one perspective, provided in an embodiment of this disclosure; Figure 12 This is a schematic diagram of the closed central vane structure of a drill bit from another perspective provided in an embodiment of this disclosure; Figure 13 This is a top view of the closed central vane structure of a drill bit provided in an embodiment of this disclosure; Figure 14 This is a schematic diagram of the structure of a drill bit with its center vane open, provided in one perspective of an embodiment of this disclosure; Figure 15 This is a schematic diagram of the drill bit's central vane opening from another perspective, provided in an embodiment of this disclosure; Figure 16 This is a top view of the drill bit with the center vane open, provided in an embodiment of the present disclosure. Figure 17 This is a schematic diagram of the structure provided in this embodiment of the invention, which closes the central winglet via a movable latch; Figure 18 This is a schematic diagram of the structure of the central wing opening according to an embodiment of the present disclosure; Figure 19 This is a schematic diagram of the structure of the movable latch opening according to an embodiment of the present disclosure; Figure 20 This is a schematic diagram of the structure of the inflation device provided in the embodiments of this disclosure; Figure 21 This is a schematic diagram of the push device provided in the embodiments of this disclosure; Figure 22 This is a schematic diagram of the structure of the first pipe sleeve of the first protective hole section provided in the embodiment of this disclosure being mounted on the fixed column; Figure 23 This is a schematic diagram of the first method for protecting a gas extraction borehole provided in this embodiment of the present disclosure; Figure 24 This is a schematic diagram of a second method for protecting a gas extraction borehole provided in this embodiment.

[0020] Figure label: 10. First protective hole section; 11. First pipe; 111. First groove; 112. Second groove; 12. Airbag assembly; 121. Airbag; 13. Suspension structure; 131. Snap-fit ​​structure; 1311. Connecting shaft; 1312. Spring; 1313. Claw; 20. Guide structure; 21. Drill pipe; 22. Drill bit; 221. Drill bit body; 222. Cutting blade; 223. Cutting teeth; 224. Center blade; 225. Center blade shaft; 226. Movable latch; 227. Movable latch shaft; 30. Inflation device; 31. Inflation pump; 311. Inflation rate regulator; 312. Display screen; 32. Inflation hose; 33. First two-way valve; 34. Second two-way valve; 35. Three-way valve; 40. Second protective hole section; 41. Second pipe; 42. Seepage hole; 43. Mortise and tenon structure; 50. Pushing device; 51. Fixed column; 52. Pushing platform; 53. Pushing rod; 60. Hole. Detailed Implementation

[0021] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0022] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0023] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0024] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0025] Unless otherwise stated, the term "multiple" means two or more.

[0026] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0027] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0029] Combination Figures 1 to 5 As shown in the figure, this disclosure provides a borehole protection device for gas extraction boreholes. The device includes a first borehole protection section 10, a guide structure 20, and an inflation device 30. The first borehole protection section 10 includes a first pipe 11, an airbag assembly 12, and a retractable suspension structure 13. Both the airbag assembly 12 and the suspension structure 13 are disposed on the outer wall of the first pipe 11. The guide structure 20 is a hollow structure, and the outer diameter of the first borehole protection section 10 is slightly smaller than the diameter of the hollow interior of the guide structure 20. The guide structure 20 is sleeved on the outside of the first borehole protection section 10 to constrain and retract the suspension structure 13 within the guide structure 20, causing the suspension structure 13 to retract into the outer wall of the first pipe 11. When the guide structure 20 is retracted, the suspension structure 13 is exposed, and simultaneously, due to the loss of constraint from the guide structure 20, the suspension structure 13 unfolds outward and then engages with the inner wall of the borehole. Thus, the first borehole protection section 10 is fixed within the borehole 60.

[0030] The inflation device 30 is connected to the airbag assembly 12. After the suspension structure 13 is engaged with the inner wall of the hole, the inflation device 30 is activated to inflate the airbag assembly 12, causing it to expand radially along the hole. Once the airbag assembly 12 is tightly fitted against the inner wall of the hole, it provides support for the hole.

[0031] Using the borehole protection device provided in this embodiment, the guide structure 20 is sleeved outside the first borehole protection section 10. On the one hand, it allows the first borehole protection section 10 to be positioned along the central axis of the borehole, thereby guiding the first borehole protection section 10. On the other hand, the guide structure 20 can constrain the suspension structure 13 inside the guide structure 20. When the guide structure 20 is retracted, the suspension structure 13 is exposed and loses its constraint, then unfolds and locks onto the inner wall of the borehole, providing initial axial anchoring for the borehole protection device. The inflation device 30 is connected to the airbag assembly 12. After the suspension structure 13 is locked onto the inner wall of the borehole, the inflation device 30 is activated to inflate the airbag assembly 12, causing the airbag assembly 12 to expand radially along the borehole. After the airbag assembly 12 is tightly fitted to the inner wall of the borehole, it provides support for the borehole. In this way, the dual dynamic support of the expansion of the suspension structure 13 and the airbag assembly 12 forms a three-dimensional support system with the radial support force generated by the expansion of the airbag assembly 12 and the axial anchoring of the suspension structure 13, significantly improving the borehole resistance of soft coal seams. The initial anchoring of the suspension structure 13 and the subsequent expansion of the airbag assembly 12 form a progressive support process, which improves the overall support strength.

[0032] Optionally, the first pipe 11 is a PVC hollow round pipe.

[0033] Optionally, combined Figures 6 to 8 As shown, the suspension structure 13 includes multiple locking structures 131, each locking structure 131 being disposed near the top end of the first pipe 11 and evenly distributed along the circumference of the outer wall of the first pipe 11. This increases the number of locking positions, preventing the device from slipping due to its own weight and improving the stability of the locking mechanism.

[0034] Optionally, see [link to relevant documentation] Figures 6 to 8The snap-fit ​​structure 131 includes a connecting shaft 1311, a spring 1312, and a claw 1313. A plurality of first grooves 111 are evenly arranged circumferentially on the outer wall of the first pipe 11. The number of first grooves 111 is equal to the number of snap-fit ​​structures 131, used to accommodate the corresponding connecting shaft 1311 and spring 1312. The connecting shaft 1311 is laterally disposed within the corresponding first groove 111, and both ends of the connecting shaft 1311 are rotatably inserted into the inner wall of the corresponding first groove 111. The first end of the spring 1312 is connected to the inner wall of the corresponding first groove 111, and the first end of the claw 1313 is connected to the second ends of the connecting shaft 1311 and the spring 1312. When the guide structure 20 is sleeved outside the first protective hole section 10, the claw 1313 is vertically retracted into the outer wall of the first pipe 11, at which time the spring 1312 is in a stretched state. When the guide structure 20 is retracted, the chuck 1313 loses its constraint and unfolds outward under the action of the spring 1312. Ultimately, the chuck 1313 is in a lateral position, and its second end is engaged with the inner wall of the hole. Thus, through the cooperation of the guide structure 20, the spring 1312, and the connecting shaft 1311, the constraint of the chuck 1313 and its automatic ejection can be achieved.

[0035] Optionally, the airbag assembly 12 includes a plurality of airbags 121. A plurality of second grooves 112 are evenly distributed circumferentially on the outer wall of the first conduit 11, and the second grooves 112 are located below the first grooves 111. Each airbag 121 is correspondingly disposed within its respective second groove 112. The inflation device 30 is connected to each airbag 121. When the inflation device 30 is not inflating any airbag 121, the airbag 121 is placed within its second groove 112. When the guide structure 20 is fitted over the first protective hole section 10, the claws 1313 are engaged with the outer side of the airbag 121.

[0036] Optionally, the number of airbags 121 and the snap-fit ​​structure 131 are the same and they correspond one-to-one in position.

[0037] Optionally, there are multiple first protective hole sections 10, and adjacent first protective hole sections 10 are connected by a mortise and tenon structure. In this way, by connecting and combining multiple first protective hole sections 10, holes of different depths can be matched, making it more convenient and flexible to use. The mortise and tenon structure can ensure that each first protective hole section 10 is tightly spliced, and compared with the commonly used threaded connection, the mortise and tenon structure is easier to assemble quickly.

[0038] Optionally, see again Figures 1 to 5 The hole protection device also includes a second hole protection section 40. The second hole protection section 40 is connected to the first hole protection section 10 via a mortise and tenon joint. See also Figures 9 to 10The second borehole section 40 includes a second pipe 41, the outer wall of which is provided with a plurality of evenly arranged seepage holes 42 that are connected to the hollow part inside the second pipe 41. While providing borehole support, the seepage holes 42 can ensure gas flow, achieving a balance between borehole support and gas extraction efficiency.

[0039] Optionally, there may be one or more first hole protection sections 10 and second hole protection sections 40, and the first hole protection sections 10 and second hole protection sections 40 may be assembled into a whole in a preset order.

[0040] Optionally, the first hole section 10 and the second hole section 40 are alternately connected as a whole.

[0041] Optionally, the various second protective hole sections 40 are connected by their own mortise and tenon structures 43. Optionally, the mortise and tenon structures 43 of the various second protective hole sections 40 are different (different directions of concave and convex) to accommodate different adjacent sections.

[0042] In this way, by combining multiple first borehole protection sections 10 and multiple second borehole protection sections 40, the borehole depth can be dynamically adapted to ensure that the borehole protection device covers the entire borehole. Furthermore, the modular combination of the first borehole protection sections 10 and the second borehole protection sections 40 allows for precise configuration of support strength according to the unstable areas of the coal seam.

[0043] Optionally, the first borehole protection section 10 and the second borehole protection section 40 can be combined as needed, depending on the specific circumstances. Specifically, the first borehole protection sections 10 are densely arranged in unstable areas to support the borehole. For example, in unstable areas, a first borehole protection section 10 is arranged at a preset distance. Optionally, the preset distance is 2 meters. The second borehole protection section 40 is arranged in ordinary areas to support the borehole and prevent gas seepage.

[0044] Optionally, the second pipe 41 is prefabricated from coal slag extracted by drilling, which can save support materials and reduce costs compared with traditional homogeneous screen pipes.

[0045] Optionally, see again Figure 2 The guide structure 20 includes a drill rod 21 and an openable / closable drill bit 22. The drill rod 21 is sleeved on the outside of the first protective hole section 10 to constrain the chuck 1313 of the suspension structure 13. The drill bit 22 is connected to the top end of the drill rod 21. The drill bit 22 is provided with a first sub-through hole, and the drill rod 21 is provided with a second sub-through hole along its own axial direction. The first sub-through hole and the second sub-through hole have the same diameter and are positioned correspondingly to form a complete hollow structure. The outer diameter of the drill bit 22 is adapted to the inner diameter of the hole. The inner diameter of the first sub-through hole and the second sub-through hole is greater than or equal to the outer diameter of the first support section (when the suspension structure 13 is not deployed and the airbag 121 is not inflated) and greater than or equal to the outer diameter of the second support section.

[0046] When support is needed for the hole, the guide structure 20 is pushed into the hole, and then the first hole-protecting section 10 is pushed into the drill rod 21 (or the first hole-protecting section 10 and the second hole-protecting section 40 are pushed into the drill rod 21 in a preset order and connected to form a whole). The guide structure 20 is then retracted, and the first hole-protecting section 10 or the second hole-protecting section 40 at the beginning pushes the drill bit 22 open and pushes it out of the drill bit 22. The air bladder 121 of the first hole-protecting section 10 is inflated only after it is fully exposed to the drill rod 21. This delayed inflation of the air bladder 121 avoids frictional damage to the air bladder 121 during the pushing process.

[0047] Optionally, the drill bit 22 and the drill rod 21 are connected by threads.

[0048] Optionally, the drill pipe 21 includes multiple pipe sections, which are connected by threads. This allows the length of the drill pipe 21 to be freely adjusted to suit the depth of the area requiring support.

[0049] Optionally, combined Figures 11 to 19 As shown, the drill bit 22 includes: a drill bit body 221, a cutter wing 222, cutting teeth 223, a central vane 224, a central vane shaft 225, a movable latch 226, and a movable latch shaft 227. The cutter wing 222 is connected to the drill bit body 221, and the cutting teeth 223 are located on the side of the cutter wing 222. A movable latch 226 is provided between the drill bit body 221 and the central vane 224. One end of the central vane 224 is hinged to the drill bit body 221 via the central vane shaft 225, and the other end is fixed in a closed state by the closed movable latch 226. The movable latch 226 can be pushed by the inside of the drill bit body 221, rotating outward around the movable latch shaft 227, allowing the central vane 224 to open outward without being restrained by the movable latch 226. During drilling, the latch fixes the central vane 224 in a closed state. The movable latch 226 can be pushed through the inside of the connecting rod, allowing the central wing 224 to open outwards without being restrained by the movable latch 226. When drilling reaches the set depth, the first hole protector section 10 or the second hole protector section 40 needs to be pushed into the hole. The top of the first hole protector section 10 or the second hole protector section 40 pushes open the movable latch 226, allowing the central wing 224 to open outwards without being restrained by the latch. At this time, the first hole protector section 10 or the second hole protector section 40 can be pushed out from the front end of the drill bit 22, pushing open the central wing 224 to enter the drill hole and complete the subsequent hole protection task.

[0050] Optionally, combined Figure 1 and Figure 20As shown, the inflation device 30 includes an air pump 31 and multiple inflation pipes 32, the number of which is equal to the number of airbags 121 located in each first protective hole section 10. The air outlet of the air pump 31 is connected to the multiple inflation pipes 32. Each inflation pipe 32 is connected to a first two-way valve 33 near the air outlet of the air pump 31. The top of each inflation pipe 32 is connected to each airbag 121 in the first protective hole section 10 of the first section through a second two-way valve 34. Each inflation pipe 32 is also equipped with a three-way valve 35, and the three-way valve 35 is located between the first two-way valve 33 and the second two-way valve 34 on the same inflation pipe 32. Each inflation pipe 32 is connected to each airbag 121 in the first protective hole section 10 located in the middle or end section through the three-way valve 35. By controlling the opening or closing of the first two-way valve 33, the second two-way valve 34, and the three-way valve 35, the inflation pump 31 can be controlled to inflate the airbag 121. In this way, a segmented air supply network is constructed using the three-way valve 35, and real-time pressure monitoring enables segmented inflation control of the airbag 121 while ensuring the sealing of the inflation device 30. The inflation pump 31 can independently control the expansion pressure of each segment of the airbag 121, achieving differentiated adjustment of support strength.

[0051] Optionally, an inflation hole is provided on the inner wall of the second groove 112, the inflation hole is sealed and connected to the airbag 121, and the inflation tube 32 is connected to the inflation hole.

[0052] Optionally, the air pump 31 is equipped with an air rate regulator 311 and a display screen 312. The air rate regulator 311 adjusts the air rate, and the display screen 312 displays the pressure value in real time, realizing independent pressure control of the segmented airbags 121. Visual monitoring of the air pressure prevents the airbags 121 from over-inflating and damaging the coal body.

[0053] Optionally, combined Figure 3 and Figure 21 As shown, the borehole protection device also includes a pushing device 50. The pushing device 50 pushes the first borehole protection section 10 and the second borehole protection section 40 into the drill rod 21 of the guide structure 20.

[0054] Optionally, see again Figure 21 The pushing device 50 includes a fixed post 51, a pushing platform 52, and a pushing rod 53. One side of the pushing platform 52 is connected to the fixed post 51, and the opposite side of the pushing platform 52 is connected to the pushing rod 53. The diameter of the fixed post 51 is slightly smaller than the inner diameter of the first pipe 11 / second pipe 41. See also... Figure 22 During operation, the first pipe 11 / second pipe 41 is fitted onto the fixed column 51, and the push rod 53 pushes the push platform 52 upward to push the first hole protection section 10 / second hole protection section 40 into the hollow drill rod 21 in sections.

[0055] Combination Figure 23As shown, based on the aforementioned borehole protection device, this disclosure provides a borehole protection method for gas drainage boreholes, including: S101, push the guide structure into the hole to a predetermined depth; S102, push the first protective hole section into the top of the guide structure; S103, retract the guide structure so that the first protective hole section pushes open the guide structure and exposes the outside of the guide structure. The suspension structure of the first protective hole section is stuck on the inner wall of the hole after losing the constraint of the guide structure. S104, inflate the airbag in the first protective hole section so that the airbag fits against the inner wall of the hole, thereby supporting the hole.

[0056] ① Drill to the designed depth using a regular drill bit.

[0057] ② Determine the number of the first hole protection sections that require the hole protection device based on the depth of the hole.

[0058] ③ Remove the ordinary drill bit and drill rod that were first drilled out of the borehole, and then send the guide structure to the designed depth.

[0059] ④ If only the first borehole protection section is used, first connect the air pump of the air inflation device to the air bladder of the first borehole protection section through the air inflation pipe. Place the first pipe of the first borehole protection section onto the fixing post of the pushing device. Start the pushing device; the pushing rod pushes the pushing platform upwards, pushing the first borehole protection section into the drill pipe of the guide structure. Then remove the fixing post. Generally, due to the depth of the borehole and / or the relatively short length of the inflated airbag in the first borehole protection section along the borehole depth, multiple first borehole protection sections need to be assembled together to support the borehole. Therefore, the inflation pipe is connected to the airbag of the next first borehole protection section via a three-way valve. The inflation pipe passes through the center of the first pipe. Then, the first pipe of the next first borehole protection section is fitted onto the fixing post, and the next first borehole protection section is pushed into the drill pipe using a pushing device. This process is repeated until all the first borehole protection sections are pushed into the drill pipe.

[0060] ⑤ Slightly retract the drill bit (remove the guide structure), the retraction distance is about 1.2 times the hole diameter. At this time, the openable drill bit is subjected to the top force of the first hole protection section located in the first section, and the central vane opens completely outward in the borehole.

[0061] ⑥ Activate the pushing device. The first hole protection section in the first segment pushes open the movable opening, and the central wing loses the restraint of the movable latch. The drill rod is withdrawn segment by segment, and the first hole protection section is pushed out from the front end of the drill bit and enters the hole.

[0062] ⑦ The pushing device pushes the first protective hole section located in the first section to the deepest point of the hole. When the chuck of the suspension structure of the first protective hole section is no longer restrained by the drill rod, the spring pulls the chuck to automatically unfold and firmly lock it into the inner wall of the hole, preventing the device from falling due to gravity. When the air bladder of the first protective hole section is fully exposed, drilling is stopped.

[0063] ⑧ Start the inflation device to inflate the airbag. When the display on the inflation pump starts to increase, adjust the inflation rate control switch to stop inflation. The airbag will expand and press tightly against the inner wall of the hole, forming a double protective barrier with the suspension device.

[0064] ⑨ Repeat the above steps to trigger the suspension structure of each first protection hole section to anchor to the inner wall of the hole, and inflate the airbags of each first protection hole section in sections by using an air pump to form three-dimensional support.

[0065] ⑩ Continue until the airbags of the last section of the first protection section are fully inflated. At this point, the drill rod is completely withdrawn from the hole. Turn off the air pump, then close all the second two-way valves and three-way valves. Finally, close all the first two-way valves and perform hole sealing and extraction.

[0066] In this way, the combination of the first protective hole section can achieve all-round support for the hole.

[0067] Combination Figure 24 As shown, based on the borehole protection device described above, this disclosure provides another borehole protection method for gas drainage boreholes, including: S101, push the guide structure into the hole to a preset depth; S102, each first protective hole section and each second protective hole section are pushed into the guide structure in a preset arrangement order, and the sections are connected to each other to form a whole; S103, retract the guide structure so that the integral formed by the connection will push the guide structure open and expose the outside of the guide structure; S104, continue to withdraw the guide structure segment by segment, so that the suspension structure of each first protective hole segment is locked onto the inner wall of the hole after losing the constraint of the guide structure, and inflate the airbag of the corresponding first protective hole segment, so that the airbag of each first protective hole segment fits into the inner wall of the hole segment by segment, thereby supporting the hole.

[0068] ① Drill to the designed depth using a conventional drill bit, monitoring the coal seam conditions during drilling and recording the locations of areas prone to instability. Specifically, a pressure sensor is installed on the conventional drill bit to detect coal seam pressure, thereby identifying areas prone to instability. Optionally, the higher the coal seam pressure, the more likely it is to become unstable.

[0069] ②Based on the location of the unstable area, determine the borehole sections that need support, and determine the number and specific connection form of the first and second borehole protection sections that require borehole protection devices.

[0070] ③ Remove the ordinary drill bit and drill rod that were first drilled out of the borehole, and then send the guide structure to the designed depth.

[0071] ④ Taking the determination that the first section uses the first protective hole section, the second to fourth sections use the second protective hole section, the fifth section uses the first protective hole section, and the sixth section uses the second protective hole section as an example: First, connect the air pump of the inflation device to the airbag of the first borehole section through the inflation pipe. Then, attach the first pipe of the first borehole section to the fixing post of the pushing device. Start the pushing device; the pushing rod pushes the pushing platform upwards, pushing the first borehole section into the drill pipe of the guide structure. Then, remove the fixing post. Then, the second pipe of the second borehole protection section is fitted onto the fixed post of the pushing device. The pushing device is activated, and the pushing rod pushes the pushing platform upwards, pushing the second borehole protection section into the drill pipe of the guide structure. This process is repeated, sequentially pushing the third and fourth sections of the second borehole protection section into the drill pipe. Then, the inflation pipe is connected to the air bladder of the first borehole protection section of the fifth section via a three-way valve. The inflation pipe passes through the center of the first pipe. The first borehole protection section of the fifth section is pushed into the drill pipe using a pushing device; Finally, the second protective hole section of the sixth segment is pushed into the drill pipe using the pushing device.

[0072] ⑤ Slightly retract the drill bit (remove the guide structure), the retraction distance is about 1.2 times the hole diameter. At this time, the openable drill bit is subjected to the top force of the first hole protection section located in the first section, and the central vane opens completely outward in the borehole.

[0073] ⑥ Activate the pushing device. The first hole protection section in the first segment pushes open the movable opening, and the central wing loses the restraint of the movable latch. The drill rod is withdrawn segment by segment, and the first hole protection section is pushed out from the front end of the drill bit and enters the hole.

[0074] ⑦ The pushing device pushes the first hole protection section located in the first segment to the deepest point of the hole. When the chuck of the suspension structure of the first hole protection section is no longer restrained by the drill rod, the spring pulls the chuck to automatically unfold and firmly lock it into the inner wall of the hole, preventing the hole protection device from falling due to gravity. When the air bladder of the first hole protection section is fully exposed, drilling is stopped.

[0075] ⑧ Start the inflation device to inflate the airbag. When the display on the inflation pump starts to increase, adjust the inflation rate control switch to stop inflation. The airbag will expand and press tightly against the inner wall of the hole, forming a double protective barrier with the suspension device.

[0076] 9. Continue withdrawing the drill bit and inflate the airbags of the first protective hole section of the fifth segment according to steps 5 to 8 above. After inflation, all airbags are fully inflated. Turn off the inflation pump, then close all second two-way valves and three-way valves, and finally close all first two-way valves.

[0077] ⑩ Continue drilling to completely remove the guide structure from the hole and then seal the hole for extraction.

[0078] In this way, by using the combination of the first and second borehole protection sections, a balance can be achieved between borehole support and gas extraction efficiency.

[0079] The foregoing description and accompanying drawings fully illustrate embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included or substituted for parts and features of other embodiments. Embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from its scope. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A borehole protection device for gas extraction boreholes, characterized in that, include: The first protective hole section includes: a first pipe, an airbag assembly, and a retractable suspension structure, wherein the suspension structure and the airbag assembly are both disposed on the outer wall of the first pipe; A guide structure is fitted outside the first protective hole section to constrain the suspension structure, so that the suspension structure is housed inside the guide structure, and when the guide structure moves and exposes the suspension structure, the suspension structure unfolds and is locked onto the inner wall of the hole; An inflation device, connected to the airbag assembly, is used to inflate the airbag assembly so that the airbag assembly fits against the inner wall of the hole and supports the hole.

2. The borehole protection device for gas extraction drilling according to claim 1, characterized in that, The suspension structure includes: Multiple snap-fit ​​structures are disposed on the outer wall of the first pipe along the circumference of the first pipe.

3. A borehole protection device for gas extraction drilling according to claim 2, characterized in that, The snap-fit ​​structure includes: A connecting shaft is provided in the first groove on the outer wall of the first pipe, and the connecting shaft is rotatably disposed in the first groove. A spring is disposed in the first groove, and the first end of the spring is connected to the inner wall of the first groove; The first end of the chuck is connected to the second end of the connecting shaft and the spring, and the second end of the chuck is used to engage with the inner wall of the hole.

4. A borehole protection device for gas extraction drilling according to claim 1, characterized in that, The airbag assembly includes: Multiple airbags, and multiple second grooves are provided on the outer wall of the first pipe, with each second groove corresponding to each of the airbags; Wherein, when the airbag is not inflated, the airbag is placed in the corresponding second groove.

5. A borehole protection device for gas extraction boreholes according to claim 1, characterized in that, There are multiple first protective hole sections, and two adjacent first protective hole sections are connected by a mortise and tenon structure.

6. A borehole protection device for gas drainage boreholes according to any one of claims 1 to 5, characterized in that, Also includes: The second protective hole section is connected to the first protective hole section; The second protective hole section includes a second pipe with seepage holes on its outer wall.

7. A borehole protection device for gas extraction drilling according to claim 6, characterized in that, Both the first protective hole section and the second protective hole section are multiple; The first protective hole section and the second protective hole section are alternately connected as a whole.

8. A borehole protection device for gas drainage boreholes according to any one of claims 1 to 5, characterized in that, The guiding structure includes: The drill rod is fitted over the first protective hole section; An openable drill bit is connected to one end of the drill rod, and the outer diameter of the drill bit is adapted to the inner diameter of the hole; When support is needed for the hole, the first hole protector section is pushed into the drill rod, and when the guide structure is retracted, the first hole protector section pushes the drill bit open to push the first hole protector section out of the drill bit.

9. A method for protecting a gas extraction borehole, characterized in that, A borehole protection device applied to a gas drainage borehole according to any one of claims 1 to 8, the method comprising: Push the guide structure into the preset depth of the hole; Push the first protective hole section into the top of the guide structure; The guide structure is retracted so that the first protective hole section pushes the guide structure open and exposes the outside of the guide structure. The suspension structure of the first protective hole section is stuck in the inner wall of the hole after losing the constraint of the guide structure. Inflate the airbag in the first protective hole section so that the airbag fits against the inner wall of the hole, thereby supporting the hole.

10. A method for protecting a gas extraction borehole, characterized in that, A borehole protection device for a gas drainage borehole according to any one of claims 1 to 8, the borehole protection device for the gas drainage borehole further comprising: a second borehole protection section, the second borehole protection section being provided with seepage holes for gas seepage, and both the first borehole protection section and the second borehole protection section being multiple; the method comprising: Push the guide structure into the preset depth of the hole; According to the preset arrangement order, each of the first protective hole segments and each of the second protective hole segments are pushed into the guide structure in sequence, and the segments are connected to each other to form a whole; The guide structure is retracted so that the integral formed by the connection pushes the guide structure open and exposes the outside of the guide structure. Continue to withdraw the guide structure segment by segment, so that the suspension structure of each first protective hole segment is locked onto the inner wall of the hole after losing the constraint of the guide structure, and inflate the airbag of the corresponding first protective hole segment, so that the airbag of each first protective hole segment fits against the inner wall of the hole segment by segment, thereby supporting the hole.

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