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

Abstract

The invention belongs to the technical field of coal mine gas extraction, and relates to a flexible wall-attached hole sealing device, a hole wall crack blocking method and a hole sealing method.The flexible wall-attached hole sealing device comprises a flexible wall-attached hole packer and an air bag, the flexible wall-attached hole packer comprises a hole-shaped flexible wall-attached material, and the outer diameter of the hole-shaped flexible wall-attached material is matched with the inner diameter of a coal seam gas extraction drill hole; the air bag comprises a central flow injection pipe and an air bag fixedly arranged on the central flow injection pipe in a sleeving mode, the front end of the central flow injection pipe penetrates through the air bag, and a flow injection hole communicated with the air bag is formed in the central flow injection pipe so that water can be injected into the air bag or air can be inflated into the air bag, and therefore the hole-shaped flexible wall-attaching material can be attached to the inner wall of the coal seam gas extraction drill hole; and / or, a plurality of grouting pipes are arranged on the outer side of the hole-shaped flexible wall-attaching material, and water is injected into the hole-shaped flexible wall-attaching material after the hole-shaped flexible wall-attaching material is attached to the inner wall of the coal seam gas extraction drill hole, so that the hole-shaped flexible wall-attaching material is solidified, and the inner wall of the coal seam gas extraction drill hole is blocked.

Description

Technical Field

[0001] The 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] In the process of coal mine gas extraction, the sealing effect of the extraction borehole directly affects the efficiency and safety of gas extraction, and 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 strata has problems such as shallow sealing depth, long sealing time, and poor sealing quality.

[0003] In view of the above problems, the existing solutions are mainly to improve the sealing effect by improving the sealing materials and sealing processes. For example, high-strength and high-flexibility sealing materials are used, or special sealing processes are used, such as the two-blocking and one-injection sealing method. However, these solutions often require a large amount of sealing materials and sealers, and the operation is complicated; in addition, due to the large amount of extraction pipes, sealers and sealing materials used in the two-blocking and one-injection sealing method, the cost of sealing a single hole is high, which brings great economic pressure to coal mining enterprises. In addition, the existing sealing materials and sealers may cause pollution to the environment during use, affecting 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 under long-term extraction, resulting in cracks between the sealing materials and the inner wall of the borehole, and between the slurry-coal (rock) mass around the borehole, causing 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 borehole, 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 hole sealing device, a hole wall fissure sealing method and a hole sealing method for coal seam gas extraction drilling holes, so as 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-attached hole sealing device for coal seam gas extraction drilling, comprising a flexible wall-attached hole sealing device and an air bag, wherein the flexible wall-attached hole sealing device comprises a hole-shaped flexible wall-attached material, and the outer diameter of the hole-shaped flexible wall-attached material 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 a plug is provided at the end thereof, and the central injection pipe is provided with an injection hole connected to the airbag, so as to inject water or inflate 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-attached material is prepared from cement blanket, so that the flexible wall-attached 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 hole sealing device, comprising the following steps:

[0015] S1. According to the requirements for plugging the cracks in the borehole wall of the coal seam gas extraction borehole and the aperture size of the gas extraction borehole, a flexible wall-attached hole sealer with a corresponding length and outer diameter is prepared;

[0016] S2. The flexible wall-attached hole sealer is sent to a designated position of the gas extraction borehole, and an airbag bag is sent into the hole-shaped flexible wall-attached material in the flexible wall-attached hole sealer, and then the airbag in the airbag bag is inflated or water-filled to make it bulge, so that the hole-shaped flexible wall-attached material is tightly attached to the hole wall of the coal seam gas extraction borehole under the compression 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 plugging of the cracks in the wall of the coal seam gas extraction borehole.

[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 tube, so that when the flexible wall sealer needs to be delivered to a designated position of the coal seam gas extraction borehole, the guide belt is forked into by the V-shaped guide fork, and then the airbag drives the flexible wall sealer to move synchronously to the bottom of the hole, and then the central injection tube is clamped by an external directional drilling rig to synchronously deliver the airbag 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 borehole for coal seam gas extraction, wherein the borehole wall fissures of the coal seam gas extraction borehole are first sealed by the borehole wall fissure sealing method, and further comprising step S4;

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

[0022] Further, it also includes 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 the cracks caused by the 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 combination with an air bag to support the sealing section of the coal seam gas extraction borehole. After forming a stable structure, a mechanical sealer is used for sealing, which effectively prevents cracking between the sealing material and the inner wall of the borehole and between the slurry-coal (rock) body 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 be better combined with the coal body to form an integral structure. It can not only prevent cracking, but also absorb impact, thus overcoming the problem of sealing failure caused by regenerated cracks due to stress disturbance.

[0027] 3. The mechanical hole 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 has high safety, 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 prior art, the present invention has a higher sealing effect, lower cost, and better environmental protection performance, and is an ideal solution for plugging and sealing cracks in the borehole wall of coal seam gas extraction boreholes.

[0029] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can 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 in conjunction with the accompanying drawings, wherein:

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

[0032] Figure 2 It is a structural schematic diagram 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 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 only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

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

[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 the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position 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 Figure 1 to Figure 3 , is a flexible wall-attached hole sealing device for coal seam gas extraction drilling, comprising a flexible wall-attached hole sealing device 1 and an air bag 2 matched therewith, the flexible wall-attached hole 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 arranged at circumferential intervals, 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 fitted with the hole 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 a plug 2011 is provided at the end thereof. The central injection pipe 201 is provided with an injection hole 2012 connected to the airbag 202, so as 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 mouth, and the opening faces the bottom of the hole, so that after the hole-shaped flexible wall material 101 is solidified, when the airbag bag 2 is withdrawn, it can automatically detach from the guide belt 2013, so as to prevent the hole-shaped flexible wall material 101 from being displaced, or the airbag bag 2 cannot be withdrawn, and other problems.

[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 hole-shaped flexible wall material 101 can be quickly solidified after adding water, thereby forming a stable hole-shaped sealing structure. In this embodiment, the hole-shaped flexible wall material 101 is made of cement blanket, and the cement blanket includes a surface layer matrix, a middle layer matrix and a bottom layer matrix arranged in sequence from the outside to the inside, and 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, and the curable mixture is filled between the surface layer matrix and the bottom layer matrix; the curable mixture includes cement, reinforcing fiber, expansion agent and accelerator; by setting the skeleton, the surface layer matrix and the bottom layer matrix can be well supported, so that there is enough 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 expansion agent, and an accelerating setting agent, the reinforcing fibers can be used as cement aggregates to enhance the compressive strength and flexural strength of the cement. By adding the expansion agent, the wall attachment effect of the porous flexible wall attachment material 101 is better. By adding the accelerating setting agent, the curing time of the porous flexible wall attachment material 101 after adding water is shortened. The skeleton includes column wires, the surface layer matrix includes an outer woven mesh and an anti-skid belt, the bottom layer matrix includes a mesh layer and an inner packaging layer, the column wires are reciprocally woven and connected with the outer woven mesh and the mesh layer, and a number of columns are formed between the outer woven mesh and the mesh layer so that a gap is left between the upper woven mesh and the mesh layer; the anti-skid belt is arranged 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. Through 3D weaving technology, the outer woven mesh, mesh layer and column wire are woven together. During weaving, the upper woven mesh and column wire combined form a dense moisture-absorbing layer, which can penetrate water during installation, so that the water moistens the cement and solidifies it. An anti-slip layer can also be installed between the upper woven mesh and the anti-slip belt to improve the overall anti-slip performance 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 fiber is a steel fiber, a new fiber or a carbon-based fiber, and both ends of the reinforcing fiber are bent to form end hooks. There is a good interface effect between the reinforcing fiber and the magnesium phosphate cement substrate, and the bonding effect is excellent. Specifically, the reinforcing fiber is selected from: end hook type fine steel fiber, length 3-6mm, diameter 0.23mm.

[0045] In another embodiment, a plurality of axially arranged water injection steel pipes are provided in the hole-shaped flexible wall material, a plug is provided at the end of the water injection steel pipe, and a plurality of axially arranged drainage holes are provided on the upper side of the water injection steel pipe to inject water into the hole-shaped flexible wall material. The water injection steel pipe can also serve as a keel after the hole-shaped flexible wall material is solidified, further improving its structural stability. Specifically, the diameter of the water injection steel pipe can be selected from DN15, DN20, DN25, etc., and can be adaptively adjusted according to the aperture of the coal seam gas extraction drilling hole.

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

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

[0048] S2. According to the requirements for plugging cracks in the borehole wall of the gas extraction borehole and the aperture size of the gas extraction borehole, a hole-shaped flexible wall material with a corresponding length and outer diameter is prepared;

[0049] S3. Deliver the hole-shaped flexible wall material to a designated position of a gas extraction borehole, deliver an airbag bag into the hole-shaped flexible wall material, and then inflate the airbag bag so that the hole-shaped flexible wall material is tightly attached to the wall of the coal seam gas extraction borehole under the pressure of the airbag bag;

[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 wall of the gas extraction borehole.

[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 tube, so that when the flexible wall sealer needs to be delivered to a designated position of the coal seam gas extraction borehole, the guide belt is forked into by the V-shaped guide fork, and then the airbag bag drives the flexible wall sealer to move synchronously to the bottom of the hole, and then the central injection tube is clamped by an external device to synchronously deliver the airbag 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 the grouting pipe to grout between the hole-shaped flexible wall material and the hole wall when necessary.

[0053] Example 2

[0054] Based on the sealing of the borehole wall cracks of the gas extraction borehole completed 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 the sealing and gas extraction of the coal seam gas extraction borehole.

[0055] Specifically, the mechanical hole 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 the cracks caused by the deformation of the coal seam gas extraction borehole during the gas extraction process.

[0057] Example 3

[0058] In this embodiment, based on the completion of sealing of the hole wall cracks of the gas extraction borehole in Embodiment 1, a grouting sealer is used to perform hole sealing grouting at the rear end of the hole-shaped flexible wall material, and the gas extraction pipe is fixed to the grouting sealer and inserted into the gas extraction hole for gas extraction, so as to achieve 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 solution of the present invention rather than to limit it. 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 solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A flexible wall-attached hole sealing device for coal seam gas extraction drilling, characterized in that: It comprises a flexible wall-attached hole sealer and an air bag, wherein the flexible wall-attached hole sealer comprises a hole-shaped flexible wall-attached material, and 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 a plug is provided at the end thereof, and the central injection pipe is provided with an injection hole connected to the airbag, so as to inject water or inflate 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 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.

2. The flexible wall-attached sealing device according to claim 1, characterized in that: 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.

3. The flexible wall-attached sealing device according to claim 1, characterized in that: The hole-shaped flexible wall-attached material is prepared from cement blanket, so that the flexible wall-attached hole sealer is solidified after water injection.

4. The flexible wall-attached sealing device according to claim 1, characterized in that: A plurality of water injection pipes are also 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.

5. 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.

6. A method for sealing cracks in a borehole wall for coal seam gas extraction, characterized in that: A flexible wall-attached sealing device as claimed in any one of claims 1 to 5 is provided, comprising the following steps: S1. According to the requirements for plugging the cracks in the borehole wall of the coal seam gas extraction borehole and the aperture size of the gas extraction borehole, a flexible wall-attached hole sealer with a corresponding length and outer diameter is prepared; S2. The flexible wall-attached hole sealer is sent to a designated position of the gas extraction borehole, and an airbag bag is sent into the hole-shaped flexible wall-attached material in the flexible wall-attached hole sealer, and then the airbag in the airbag bag is inflated or water-filled to make it bulge, so that the hole-shaped flexible wall-attached material is tightly attached to the hole wall of the coal seam gas extraction borehole under the compression 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 plugging of the cracks in the wall of the coal seam gas extraction borehole.

7. The method for plugging cracks in a hole wall according to claim 6, 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 tube, 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 forked into by 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 tube 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.

8. The method for plugging hole wall cracks according to claim 6, 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.

9. A method for sealing a borehole for coal seam gas extraction, characterized in that: The hole wall fissure plugging method according to claim 8 is used to first plug the hole wall fissures of the coal seam gas extraction borehole, and further comprises step S4; S4. Use a mechanical hole sealer with a gas extraction tube to seal the hole in the hole of the hole-shaped flexible wall material that has been cured. After the hole is sealed, the mechanical hole sealer can be connected to the gas extraction system to extract gas.

10. The sealing method according to claim 9, 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 the cracks caused by the deformation of the coal seam gas extraction borehole during the gas extraction process.

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