Flexible wall-attached hole sealing device, hole wall crack sealing method and hole sealing method

Abstract

The present invention belongs to the technical field of coal mine gas extraction, and relates to a flexible wall-attached hole sealing device, a hole wall fissure sealing method and a hole sealing method, comprising a flexible wall-attached hole sealer and an air bag. The flexible wall-attached hole sealer comprises a hole-shaped flexible wall-attached material, the outer diameter of the hole-shaped flexible wall-attached material matches the inner diameter of the coal seam gas extraction borehole; the air bag comprises a central injection tube and an air bag fixedly sleeved on the central injection tube, the front end of the central injection tube passes through the air bag, and the central injection tube is provided with an injection hole connected to the air bag, so as to inject water or inflate the air bag, so that the hole-shaped flexible wall-attached material is fitted with the inner wall of the coal seam gas extraction borehole; and / or, a plurality of grouting pipes are arranged on the outside of the hole-shaped flexible wall-attached material, and water is injected into the hole-shaped flexible wall-attached material after the hole-shaped flexible wall-attached material is fitted with the inner wall of the coal seam gas extraction borehole, so that the hole-shaped flexible wall-attached material is solidified, thereby sealing the inner wall of the coal seam gas extraction borehole.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mine gas extraction, and relates to a flexible wall-attached hole sealing device for coal seam gas extraction drilling holes, a hole wall fissure sealing method, and a hole sealing method. Background Art

[0002] During the coal mine gas extraction process, the sealing effect of the extraction borehole directly affects the efficiency and safety of gas extraction. The sealing quality of the gas extraction borehole is a key factor affecting the gas extraction effect. However, most of the borehole sealing in my country's soft and protruding coal seams or loose formations have problems such as shallow sealing depth, long sealing time, and poor sealing quality.

[0003] To address the above issues, existing solutions primarily focus on improving sealing effects by improving sealing materials and processes. For example, high-strength, high-flexibility sealing materials or specialized sealing processes, such as the "two-blocking, one-injection" sealing method, are employed. However, these solutions often require large quantities of sealing materials and sealers, and are complex to operate. Furthermore, the large amount of extraction pipes, sealers, and sealing materials used in the "two-blocking, one-injection" sealing method results in high sealing costs per hole, placing significant financial pressure on coal mining companies. Furthermore, existing sealing materials and sealers can pollute the environment during use, impacting the environmental benefits of coal mines.

[0004] Secondly, the existing sealing materials and sealing processes are easily affected by the disturbance of the coal and rock mass around the borehole during long-term extraction, resulting in cracks between the sealing material and the inner wall of the borehole, and between the slurry and coal (rock) mass around the borehole. This causes a large amount of external air to leak into the borehole under the action of negative pressure, causing the gas extraction volume fraction to decay in the middle and late stages of the extraction drilling, thereby affecting the efficiency and safety of gas extraction. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a flexible wall-attached sealing device for coal seam gas extraction drilling holes, a hole wall crack sealing method and a hole sealing method to solve the problems raised in the background technology.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A flexible wall-attachment sealing device for coal seam gas extraction drilling, comprising a flexible wall-attachment sealing device and an air bag. The flexible wall-attachment sealing device comprises a hole-shaped flexible wall-attachment material, the outer diameter of which matches the inner diameter of the coal seam gas extraction drilling hole.

[0008] The airbag bag is arranged in the hole-shaped flexible wall material, including a central injection pipe and an airbag fixedly sleeved on the central injection pipe. The front end of the central injection pipe passes through the airbag and is provided with a plug at the end. The central injection pipe is provided with an injection hole connected to the airbag to inject water or air into the airbag, so that the hole-shaped flexible wall material fits the inner wall of the coal seam gas extraction borehole;

[0009] And / or, a plurality of grouting pipes are arranged on the outside of the hole-shaped flexible wall material, and water is injected into the hole-shaped flexible wall material after the hole-shaped flexible wall material is attached to the inner wall of the coal seam gas extraction borehole, so that the hole-shaped flexible wall material is solidified, thereby sealing the inner wall of the coal seam gas extraction borehole.

[0010] Furthermore, a guide belt is provided at one end of the hole-shaped flexible wall material close to the bottom of the gas extraction borehole, and a V-shaped guide fork matching the guide belt is provided on the plug to deliver the flexible wall sealer to a designated position in the gas extraction borehole through the central injection pipe.

[0011] Furthermore, the hole-shaped flexible wall-attachment material is made of cement blanket, so that the flexible wall-attachment hole sealer is solidified after water injection.

[0012] Furthermore, a plurality of water injection pipes are provided on the outside of the airbag, a plug is provided at the end of the water injection pipe, and a plurality of drainage holes arranged in sequence along the axial direction are provided on the side of the water injection pipe close to the hole-shaped flexible wall material to inject water into the hole-shaped flexible wall material to accelerate the solidification of the hole-shaped flexible wall material.

[0013] Furthermore, a plurality of axially arranged water injection steel pipes are provided in the hole-shaped flexible wall material, plugs are provided at the ends of the water injection steel pipes, and a plurality of axially arranged drainage holes are provided on the upper side of the water injection steel pipes to inject water into the hole-shaped flexible wall material.

[0014] A method for sealing cracks in a borehole wall for coal seam gas extraction, providing the flexible wall-attached sealing device, comprises the following steps:

[0015] S1. Prepare a flexible wall sealer of corresponding length and outer diameter based on the requirements for sealing the wall fissures of the coal seam gas extraction borehole and the borehole diameter of the gas extraction borehole;

[0016] S2. Deliver the flexible wall sealer to a designated location within the gas extraction borehole, insert an airbag into the porous flexible wall material within the flexible wall sealer, and then inflate the airbag within the airbag by air or water, thereby causing the porous flexible wall material to adhere tightly to the wall of the coal seam gas extraction borehole under the pressure of the airbag.

[0017] S3. Inject water into the hole-shaped flexible wall material to solidify the hole-shaped flexible wall material. After the hole-shaped flexible wall material is solidified, deflate the air bag or pump out the water to complete the sealing of the cracks in the coal seam gas extraction borehole wall.

[0018] Furthermore, in step S2, a guide belt is provided at one end of the hole-shaped flexible wall material close to the bottom of the hole, and a V-shaped guide fork matching the guide belt is provided on the plug of the central injection pipe, so that when the flexible wall sealer needs to be delivered to the designated position of the coal seam gas extraction borehole, the guide belt is inserted through the V-shaped guide fork, and then the air bag drives the flexible wall sealer to move synchronously to the bottom of the hole, and then the central injection pipe is clamped by an external directional drilling rig to synchronously deliver the air bag and the flexible wall sealer to the designated position of the coal seam gas extraction borehole.

[0019] Furthermore, in step S3, water is injected into the hole-shaped flexible wall material through a plurality of grouting pipes arranged outside the hole-shaped flexible wall material to solidify the hole-shaped flexible wall material, thereby sealing the inner wall of the coal seam gas extraction borehole.

[0020] A method for sealing a coal seam gas extraction borehole, which first seals the borehole wall fissures of the coal seam gas extraction borehole using the above-mentioned borehole wall fissure sealing method, and further includes step S4;

[0021] S4. Use a mechanical sealer with a gas extraction tube to seal the hole in the hole of the porous flexible wall material that has been cured. After the hole is sealed, the mechanical sealer can be connected to the gas extraction system to extract gas.

[0022] Furthermore, the method further comprises step S5;

[0023] S5. During the gas extraction process, secondary grouting is performed between the hole-shaped flexible wall material and the inner wall of the coal seam gas extraction borehole through the grouting pipe to seal cracks caused by deformation of the coal seam gas extraction borehole during the gas extraction process.

[0024] The beneficial effects of the present invention are:

[0025] 1. The present invention adopts a flexible wall-attached sealer in conjunction with an air bag to support the sealing section of the coal seam gas extraction borehole. After forming a stable structure, it is sealed with a mechanical sealer, effectively preventing cracking between the sealing material and the inner wall of the borehole, and between the slurry and coal (rock) around the borehole caused by disturbance of the coal and rock mass around the borehole, thereby improving the efficiency and safety of gas extraction.

[0026] 2. The hole-shaped flexible wall material in the flexible wall sealer of the present invention has high strength and good flexibility, and can better combine with the coal body to form an integral structure. It can not only prevent cracking, but also absorb impact, overcoming the problem of sealing failure caused by regeneration cracks due to stress disturbance.

[0027] 3. The mechanical sealer of the present invention adopts a multi-section flexible rubber arrangement, has good sealing performance, and is reusable, which greatly reduces the sealing cost and alleviates the economic pressure of coal mining enterprises. The material of the present invention is highly safe, does not release heat in the reaction, is resistant to corrosion, has good flame retardant and antistatic properties, is environmentally friendly, and is beneficial to the environmental benefits of coal mines.

[0028] In general, compared with the existing technology, the present invention has a higher sealing effect, lower cost, and better environmental performance. It is an ideal solution for sealing and plugging cracks in the borehole wall of coal seam gas extraction boreholes.

[0029] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0031] Figure 1 Schematic diagram of the principle of a flexible wall-attached sealing device for coal seam gas extraction drilling in an embodiment;

[0032] Figure 2 Schematic diagram of the structure of the flexible wall-attached hole sealer in the embodiment;

[0033] Figure 3 Schematic diagram of the structure of the airbag bag in the embodiment.

[0034] Figure numerals: flexible wall sealer 1, hole-shaped flexible wall material 101, guide belt 102, grouting pipe 103, air bag 2, central injection pipe 201, plug 2011, injection hole 2012, V-shaped guide fork 2013, air bag 202, coal seam gas extraction drilling hole 3. DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0036] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0037] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0038] See also Figures 1 to 3 , is a flexible wall-attached sealing device for coal seam gas extraction drilling, comprising a flexible wall-attached sealing device 1 and an air bag 2 matched therewith, the flexible wall-attached sealing device 1 comprising a hole-shaped flexible wall-attached material 101, a guide belt 102 and a grouting pipe 103, the outer diameter of the hole-shaped flexible wall-attached material 101 matches the inner diameter of the coal seam gas extraction drilling hole 3, the guide belt 102 is connected to one end of the hole-shaped flexible wall-attached material 101 close to the bottom of the gas extraction drilling hole 3, and is used to guide the hole-shaped flexible wall-attached material 101 into a designated position in the gas extraction drilling hole 3, the grouting pipe 103 is fixedly arranged on the outside of the hole-shaped flexible wall-attached material 101 and is evenly spaced circumferentially, and is used to inject water into the hole-shaped flexible wall-attached material 101 to solidify it, thereby sealing the coal seam gas extraction drilling hole 3;

[0039] The airbag bag 2 is arranged in the hole-shaped flexible wall material 101 so that the hole-shaped flexible wall material 101 is fully adhered to the wall of the gas extraction borehole 3 after the airbag 202 is filled with water or inflated. It includes a central injection pipe 201 and an airbag 202 fixedly sleeved on the central injection pipe 201. The front end of the central injection pipe 201 passes through the airbag 202 and is provided with a plug 2011 at the end. The central injection pipe 201 is provided with an injection hole 2012 connected to the airbag 202 to inject water or inflate the airbag 202;

[0040] Furthermore, a V-shaped guide fork 2013 matching the guide belt 102 is provided on the plug 2011, so that when the flexible wall sealer 1 needs to be sent to the specified position in the gas extraction borehole 3, the guide belt 102 can be placed in the V-shaped guide fork 2013, and the flexible wall sealer 1 and the airbag bag 2 can be synchronously sent to the specified position in the gas extraction borehole 3 through the central injection pipe 201; and the V-shaped guide fork 2013 is an open fork, and the opening is facing the bottom of the hole, so that after the hole-shaped flexible wall material 101 is solidified, the airbag bag 2 can automatically detach from the guide belt 2013 when it is withdrawn, so as to prevent the hole-shaped flexible wall material 101 from being displaced or the airbag bag 2 from being unable to withdraw.

[0041] In another embodiment, a plurality of water injection pipes are provided on the outside of the airbag 202, a plug is provided at the end of the water injection pipe, and a plurality of drainage holes arranged in sequence along the axial direction are provided on the side of the water injection pipe close to the hole-shaped flexible wall material 101 to inject water into the hole-shaped flexible wall material 101 to accelerate the solidification of the hole-shaped flexible wall material 101.

[0042] The porous flexible wall material 101 can quickly solidify after adding water, thereby forming a stable porous sealing structure. In this embodiment, the porous flexible wall material 101 is made of a cement blanket, which includes a surface layer matrix, a middle layer matrix, and a bottom layer matrix arranged in sequence from the outside to the inside. The middle layer matrix includes a skeleton and a curable mixture. The outer side of the skeleton is connected to the surface layer matrix, and the inner side is connected to the bottom layer matrix. The curable mixture is filled between the surface layer matrix and the bottom layer matrix. The curable mixture includes cement, reinforcing fiber, an expansion agent, and an accelerator. By providing the skeleton, the surface layer matrix and the bottom layer matrix can be well supported, so that there is sufficient space between the surface layer matrix and the bottom layer matrix to accommodate the curable mixture. The cement is specifically a magnesium phosphate cement matrix. By filling the cement with reinforcing fibers, an expansive agent, and an accelerating setting agent, the reinforcing fibers can be used as cement aggregate to enhance the compressive strength and flexural strength of the cement. The addition of the expansive agent improves the wall attachment effect of the porous flexible wall attachment material 101, and the addition of the accelerating setting agent shortens the curing time of the porous flexible wall attachment material 101 after adding water. The skeleton includes column wires, the surface layer matrix includes an outer woven mesh and an anti-skid tape, and the bottom layer matrix includes a mesh layer and an inner packaging layer. The column wires are woven and connected to the outer woven mesh and the mesh layer in a reciprocating manner, and a number of columns are formed between the outer woven mesh and the mesh layer to leave a gap between the upper woven mesh and the mesh layer. The anti-skid tape is provided on the upper side of the upper woven mesh. The lower packaging layer is connected to the lower side of the mesh layer by bonding. Using 3D weaving technology, the outer mesh, mesh layer, and column lines are woven together. During weaving, the area where the upper mesh meets the column lines forms a dense, moisture-absorbing layer. This allows water to penetrate during installation, moistening the cement and causing it to solidify. An anti-slip layer can also be installed between the upper mesh and the anti-slip tape to enhance the overall anti-slip properties of the cement blanket.

[0043] The material of the outer woven mesh is one of carbon fiber, basalt fiber, ultra-high molecular weight polyethylene, steel fiber, steel wire, polyester, and nylon; the material of the column line is one of carbon fiber, basalt fiber, ultra-high molecular weight polyethylene, steel fiber, steel wire, polyester, and nylon; the material of the lower packaging layer is one of carbon fiber, basalt fiber, ultra-high molecular weight polyethylene, steel fiber, and steel wire.

[0044] The reinforcing fibers are selected from steel fibers, novel fibers, or carbon-based fibers, each bent at both ends to form hooks. This creates a good interfacial effect between the reinforcing fibers and the magnesium phosphate cement matrix, resulting in excellent bonding. Specifically, the reinforcing fibers are selected from fine steel fibers with hooked ends, 3-6 mm in length and 0.23 mm in diameter.

[0045] In another embodiment, several axially arranged water injection steel pipes are provided within the hole-shaped flexible wall material. These pipes are terminated with plugs and have a plurality of axially arranged drainage holes on their upper sides for injecting water into the hole-shaped flexible wall material. These pipes also serve as support for the cured hole-shaped flexible wall material, further enhancing its structural stability. Specifically, the pipe diameters of these pipes can be selected from DN15, DN20, DN25, etc., and can be adjusted adaptively based on the diameter of the coal seam gas extraction borehole.

[0046] This embodiment also provides a method for sealing cracks in a borehole wall for coal seam gas extraction, which specifically includes the following steps:

[0047] S1. Determine the drilling location based on the coal seam conditions and construct a coal seam gas extraction borehole 3 according to the design requirements;

[0048] S2. Prepare a flexible wall material with a corresponding length and outer diameter based on the requirements for plugging cracks in the gas extraction borehole wall and the borehole diameter;

[0049] S3. Delivering the porous flexible wall material to a designated location of the gas extraction borehole, and placing an air bag inside the porous flexible wall material, and then inflating the air bag so that the porous flexible wall material is squeezed by the air bag and closely adheres to the wall of the coal seam gas extraction borehole;

[0050] S4. Inject water into the hole-shaped flexible wall material to solidify the hole-shaped flexible wall material. After the hole-shaped flexible wall material is solidified, deflate and remove the airbag bag to complete the sealing of the cracks in the gas extraction borehole wall.

[0051] Furthermore, in step S2, a guide belt is provided at one end of the hole-shaped flexible wall material close to the bottom of the hole, and a V-shaped guide fork matching the guide belt is provided on the plug of the central injection pipe, so that when the flexible wall sealer needs to be delivered to the designated position of the coal seam gas extraction borehole, the guide belt is inserted through the V-shaped guide fork, and then the air bag drives the flexible wall sealer to move synchronously to the bottom of the hole, and then the central injection pipe is clamped by an external device to synchronously deliver the air bag and the flexible wall sealer to the designated position of the coal seam gas extraction borehole.

[0052] Specifically, the external device can be a drilling rig or other device that can clamp the central injection pipe and feed it. The tail end of the central injection pipe is connected to an external air source or water source to inflate or inject water into the airbag; similarly, the grouting pipe 103, the water injection pipe, and the water injection steel pipe are connected to an external water source to inject water into the hole-shaped flexible wall material, and the grouting pipe 103 can also be switched to be connected to the slurry injection pipe to perform grouting between the hole-shaped flexible wall material and the hole wall when needed.

[0053] Example 2

[0054] Based on the completion of sealing the wall cracks of the gas extraction borehole in Example 1, this embodiment uses a mechanical sealer with a gas extraction tube to seal the hole in the hole of the hole-shaped flexible wall material, and connects the mechanical sealer through a gas extraction system to perform gas extraction, so as to achieve sealing and gas extraction of the coal seam gas extraction borehole.

[0055] Specifically, the mechanical sealer is arranged with multiple sections of flexible rubber, has good sealing performance, and can be taken out and reused after gas extraction is completed, so as to reduce costs and consumables.

[0056] Furthermore, during the gas extraction process, secondary grouting is performed between the hole-shaped flexible wall material and the inner wall of the coal seam gas extraction borehole through the grouting pipe to seal cracks caused by deformation of the coal seam gas extraction borehole during the gas extraction process.

[0057] Example 3

[0058] Based on the completion of sealing the wall cracks of the gas extraction borehole in Example 1, this embodiment uses a grouting sealer to perform hole sealing grouting at the rear end of the hole-shaped flexible wall material, and fixes the gas extraction pipe on the grouting sealer and inserts it into the gas extraction hole for gas extraction, so as to achieve the sealing of the coal seam gas extraction borehole.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A flexible wall-attached sealing device for coal seam gas extraction drilling, characterized by: It includes a flexible wall-attached hole sealer and an air bag. The flexible wall-attached hole sealer includes a hole-shaped flexible wall-attached material. The outer diameter of the hole-shaped flexible wall-attached material matches the inner diameter of the coal seam gas extraction borehole. The airbag bag is arranged in the hole-shaped flexible wall material, including a central injection pipe and an airbag fixedly sleeved on the central injection pipe. The front end of the central injection pipe passes through the airbag and is provided with a plug at the end. The central injection pipe is provided with an injection hole connected to the airbag to inject water or air into the airbag, so that the hole-shaped flexible wall material fits the inner wall of the coal seam gas extraction borehole; and / or, a plurality of grouting pipes are arranged outside the hole-shaped flexible wall material, and water is injected into the hole-shaped flexible wall material after the hole-shaped flexible wall material is attached to the inner wall of the coal seam gas extraction borehole, so that the hole-shaped flexible wall material solidifies, thereby sealing the inner wall of the coal seam gas extraction borehole; A guide belt is provided at one end of the hole-shaped flexible wall material close to the bottom of the gas drainage borehole, and a V-shaped guide fork matching the guide belt is provided on the plug to deliver the flexible wall sealer to a designated position in the gas drainage borehole through the central injection pipe; The hole-shaped flexible wall-attachment material is prepared from cement blanket, so that the flexible wall-attachment hole sealer is solidified after water injection.

2. The flexible wall-attached sealing device according to claim 1, characterized in that: A plurality of water injection pipes are provided on the outside of the airbag, a plug is provided at the end of the water injection pipe, and a plurality of drainage holes arranged in sequence along the axial direction are provided on the side of the water injection pipe close to the hole-shaped flexible wall material to inject water into the hole-shaped flexible wall material to accelerate the solidification of the hole-shaped flexible wall material.

3. The flexible wall-attached sealing device according to claim 1, characterized in that: A plurality of axially arranged water injection steel pipes are provided in the hole-shaped flexible wall material, plugs are provided at the ends of the water injection steel pipes, and a plurality of axially arranged drainage holes are provided on the upper side of the water injection steel pipes to inject water into the hole-shaped flexible wall material.

4. A method for sealing cracks in a borehole for coal seam gas extraction, characterized in that: Provided is a flexible wall-attached sealing device as claimed in any one of claims 1 to 3, comprising the following steps: S1. Prepare a flexible wall sealer of corresponding length and outer diameter based on the requirements for sealing the wall fissures of the coal seam gas extraction borehole and the borehole diameter of the gas extraction borehole; S2. Deliver the flexible wall sealer to a designated location within the gas extraction borehole, insert an airbag into the porous flexible wall material within the flexible wall sealer, and then inflate the airbag within the airbag by air or water, thereby causing the porous flexible wall material to adhere tightly to the wall of the coal seam gas extraction borehole under the pressure of the airbag. S3. Inject water into the hole-shaped flexible wall material to solidify the hole-shaped flexible wall material. After the hole-shaped flexible wall material is solidified, deflate the air bag or pump out the water to complete the sealing of the cracks in the coal seam gas extraction borehole wall.

5. The hole wall crack sealing method according to claim 4, characterized in that: In step S2, a guide belt is provided at one end of the hole-shaped flexible wall material close to the bottom of the hole, and a V-shaped guide fork matching the guide belt is provided on the plug of the central injection pipe, so that when the flexible wall sealer needs to be delivered to the designated position of the coal seam gas extraction borehole, the guide belt is inserted through the V-shaped guide fork, and then the air bag drives the flexible wall sealer to move synchronously to the bottom of the hole, and then the central injection pipe is clamped by an external device to synchronously deliver the air bag and the flexible wall sealer to the designated position of the coal seam gas extraction borehole.

6. The hole wall crack sealing method according to claim 4, characterized in that: In step S3, water is injected into the hole-shaped flexible wall material through a plurality of grouting pipes arranged outside the hole-shaped flexible wall material to solidify the hole-shaped flexible wall material, thereby sealing the inner wall of the coal seam gas extraction borehole.

7. A method for sealing a borehole for coal seam gas extraction, characterized in that: The hole wall fissure sealing method according to claim 6 is used to first seal the hole wall fissures of the coal seam gas extraction borehole, and further comprises step S4; S4. Use a mechanical sealer with a gas extraction tube to seal the hole in the hole of the porous flexible wall material that has been cured. After the hole is sealed, the mechanical sealer can be connected to the gas extraction system to extract gas.

8. The sealing method according to claim 7, characterized in that: Also includes step S5; S5. During the gas extraction process, secondary grouting is performed between the hole-shaped flexible wall material and the inner wall of the coal seam gas extraction borehole through the grouting pipe to seal cracks caused by deformation of the coal seam gas extraction borehole during the gas extraction process.

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