A gas extraction hole coating device and hole wall coating-fracture grouting coordinated hole sealing method

Abstract

The present invention belongs to the field of gas extraction and sealing equipment and technology, and specifically discloses a gas extraction hole coating device and a hole wall coating-crack grouting coordinated sealing method. The gas extraction hole coating device includes a central injection pipe, a plug, a front plugging bag, a middle plugging bag, a rear plugging bag, an injection hole, a coating pipe, a ball valve and a pressure gauge. Compared with the existing technology, the gas extraction hole coating device of the present invention has a simple structure and stable performance, can achieve coating of the inner wall of the gas extraction hole, form a stable and uniform coating, and can fully penetrate and fill the cracks; the gas extraction hole coating device of the present invention has a simple coating operation, does not involve complex machinery, electromechanical equipment, and has high safety; the gas extraction hole coating device of the present invention is combined with a conventional grouting sealing method to achieve high-quality sealing of the gas extraction borehole.

Description

Technical Field

[0001] The present invention relates to the field of gas extraction hole sealing equipment and technology, in particular to a gas extraction hole coating device and a hole wall coating-fracture grouting coordinated hole sealing method. Background Art

[0002] The sealing quality of gas extraction boreholes is a key factor affecting gas extraction effectiveness. Most boreholes in my country, located in soft, protruding coal seams or loose formations, face challenges such as sealing difficulties and difficulty inserting sealers. This leads to shallow sealing depths, long sealing times, and poor sealing quality. In-hole spraying offers a new approach to borehole sealing. Patents 201310282333.3 and 201510298907.5 propose spraying the inner wall of the borehole with a coating, thereby increasing the sealing performance of the borehole wall. This significantly increases the sealing depth and is of great significance for preventing and controlling gas leakage during gas extraction. However, the above patents have the following problems: (1) It is difficult to spray the inner wall of the borehole by spraying, and the spraying operation needs to be carried out in a very small space inside the borehole, and relies on large electromechanical equipment outside the hole; (2) The deformation of the borehole wall is uncontrollable, that is, some areas are in a state of small deformation, and some areas of the borehole cracks are large or even collapsed. In this case, only the surface of the cracks is sprayed by spraying, and the cracks cannot be fully filled, that is, it is difficult to achieve the sealing of large cracks in the hole wall.

[0003] Therefore, in response to the above problems, there is an urgent need to develop a gas extraction hole coating device and a hole wall coating-fracture grouting coordinated sealing process to meet the needs of actual use. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a gas extraction hole coating device and a hole wall coating-fracture grouting coordinated hole sealing method.

[0005] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0006] The first object of the present invention is to provide a gas extraction hole injection device, including a central injection tube, a plug is provided at the front end of the central injection tube; the gas extraction hole injection device also includes a front plugging bag, a middle plugging bag and a rear plugging bag that are interconnected, the front end of the central injection tube passes through the centers of the rear plugging bag, the middle plugging bag and the front plugging bag in sequence, the front end of the front plugging bag is fixed on the outer wall of the central injection tube, and the rear end of the rear plugging bag is fixed on the outer wall of the central injection tube, and the central injection tubes located in the front plugging bag and the rear plugging bag are both provided with injection holes for injecting fluid into the front plugging bag and the rear plugging bag, the outer diameter of the middle plugging bag is smaller than the outer diameter of the rear plugging bag and the front plugging bag after being filled with fluid, and an annular cavity is formed between the front end of the rear plugging bag and the rear end of the front plugging bag after being filled with fluid and the outer wall of the middle plugging bag; an injection tube for injecting quick-setting slurry into the annular cavity is provided through the front and rear end side walls of the rear plugging bag, and the ends of the central injection tube and the injection tube are both equipped with ball valves and pressure gauges.

[0007] Furthermore, a layer of plastic film is attached to the outer wall of the middle blocking sac, the front end side wall of the rear blocking sac, and the rear end side wall of the front blocking sac.

[0008] Furthermore, after being filled with fluid, the outer diameters of the rear blocking bladder and the front blocking bladder are the same, the axial lengths of the rear blocking bladder and the front blocking bladder are 0.5-1.0 m, and the length of the middle blocking bladder is 0.5-5 m.

[0009] Preferably, the number of injection holes on the central injection tubes in the front blocking bag and the rear blocking bag is set to 1-10.

[0010] Preferably, the central injection tube is fixed to the front blocking bag and the rear blocking bag by gluing, pressing ring or binding.

[0011] Furthermore, the fluid injected into the front plugging bag and the rear plugging bag is downhole compressed air / high-pressure water.

[0012] A second object of the present invention is to provide a hole wall coating and fissure grouting coordinated hole sealing method, which utilizes the above-mentioned gas extraction hole coating device to perform hole wall coating and coordinate with fissure grouting to seal the hole, comprising the following steps:

[0013] S1: inserting the coating device into the gas extraction hole to a specified depth, so that the rear end of the rear plugging bag is L1 away from the orifice of the gas extraction hole, injecting fluid into the rear plugging bag, the middle plugging bag, and the front plugging bag through the central injection pipe, so that the rear plugging bag and the front plugging bag are fully expanded so that the outer walls are tightly attached to the inner wall of the gas extraction hole, and closing the ball valve on the central injection pipe after reaching a predetermined pressure;

[0014] S2: Injecting quick-setting material into the annular cavity through the coating pipe to form an annular coating layer in the annular cavity; after the annular coating layer is completely solidified, the fluid inside the rear plugging bladder, the middle plugging bladder, and the front plugging bladder is released, so that the rear plugging bladder, the middle plugging bladder, and the front plugging bladder are separated from the gas extraction hole and the annular coating layer, and the coating device in the gas extraction hole is removed, and the annular coating layer remains in the gas extraction hole, completing the hole wall coating;

[0015] S3: Insert a conventional grouting sealer into the gas extraction hole after the hole wall is coated. The distance between the front end of the grouting sealer and the mouth of the gas extraction hole is not less than L1. The front end of the grouting sealer is in close contact with the rear end of the annular coating layer. Then grouting is performed on the grouting sealer. After the grouting is completed, wait for the material to solidify and complete the hole sealing, and then coal seam gas extraction can begin.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The gas extraction hole coating device of the present invention has a simple structure and stable performance, and can realize coating of the inner wall of the gas extraction hole to form a stable and uniform coating, and can fully penetrate and fill the cracks.

[0018] (2) The gas extraction hole coating device of the present invention has simple coating operation, does not involve complicated mechanical and electromechanical equipment, and has high safety.

[0019] (3) The gas extraction hole coating device of the present invention is combined with a conventional grouting and sealing method to achieve high-quality sealing of the gas extraction borehole. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the gas extraction hole injection device of the present invention.

[0021] Figure 2 Schematic diagram of the formation of annular coating in the gas extraction hole.

[0022] Figure 3 Schematic diagram of the coordinated hole sealing process of hole wall coating and crack grouting. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] like Figure 1As shown, this embodiment provides a gas extraction hole injection device 1, including a central injection tube 11, and a plug 14 is provided at the front end of the central injection tube 11; the gas extraction hole injection device also includes a front plugging bag 13, a middle plugging bag 20 and a rear plugging bag 12 that are interconnected, and the front end of the central injection tube 11 passes through the center of the rear plugging bag 12, the middle plugging bag 20 and the front plugging bag 13 in sequence, the front end of the front plugging bag 13 is fixed on the outer wall of the central injection tube 11, and the rear end of the rear plugging bag 12 is fixed on the outer wall of the central injection tube 11, and the central injection tube 11 located in the front plugging bag 13 and the rear plugging bag 12 is provided with an injection hole 15 for injecting fluid into the front plugging bag 13 and the rear plugging bag 12. The middle plugging bag 20 in this example can be a hard tube and its outer diameter is smaller than the outer diameter of the rear plugging bag 12 and the front plugging bag 13 after being filled with fluid. For example, as Figure 1 As shown, in this embodiment, the outer diameters of the rear plugging bladder 12 and the front plugging bladder 13 after being filled with fluid are the same, the axial lengths of the rear plugging bladder 12 and the front plugging bladder 13 are 0.5-1.0m, and the length of the middle plugging bladder 20 is 0.5-5m; an annular cavity 3 is formed between the front end of the rear plugging bladder 12 and the rear end of the front plugging bladder 13 after being filled with fluid and the outer wall of the middle plugging bladder 20; an injection pipe 16 for injecting quick-setting slurry into the annular cavity 3 is provided through the front and rear end side walls of the rear plugging bladder 13. In order to facilitate the control of the injection pressure and grouting pressure, ball valves 18 and pressure gauges 19 are installed at the ends of the central injection pipe 11 and the injection pipe 16.

[0025] When used, such as Figure 2 As shown, it will be Figure 1 The gas extraction hole injection coating device shown is inserted into the specified depth of the gas extraction hole 2, and then fluid such as water, compressed air, mucus and other materials are injected into the central injection pipe 11, so that the front plugging bag 12 and the rear plugging bag 13 of the gas extraction hole injection coating device 1 are tightly fitted with the borehole 2, and the diameters of the front plugging bag 12 and the rear plugging bag 13 are larger than the diameter of the middle plugging bag 20. At this time, the outer walls of the front plugging bag 12 and the rear plugging bag 13 are tightly fitted with the inner wall of the gas extraction hole 2, and an annular cavity 3 is formed between the front end of the rear plugging bag 12 and the rear end of the front plugging bag 13 and the outer wall of the middle plugging bag 20. Quick-setting slurry (such as quick-setting cement, quick-setting polymer, quick-setting polyurethane and other slurry materials) is injected into the annular cavity 3 through the injection pipe 16. At this time, an annular injection coating layer 31 is formed in the annular cavity 3. The annular injection coating layer 31 is a hollow cylinder with an annular cross-section, and the outer wall of the hollow cylinder is connected to the inner wall of the gas extraction hole 2 as a whole.

[0026] Of course, in some embodiments, the middle plugging bag 20 may also be made of a harder thick bag, etc., the purpose of which is to support the quick-setting slurry injected into the annular cavity 3 to form an annular injection coating 31.

[0027] After the annular injection coating layer 31 is formed in the annular cavity 3, after the fluid injected into the rear blocking capsule 12, the middle blocking capsule 20, and the front blocking capsule 13 is released, in order to facilitate the removal of the rear blocking capsule 12, the middle blocking capsule 20, and the front blocking capsule 13, a layer of plastic film 17 is pasted on the outer wall of the middle blocking capsule 20 and the front end side wall of the rear blocking capsule 12 and the rear end side wall of the front blocking capsule 13. The plastic film 17 is not bonded to the inner wall of the formed annular injection coating layer 31, so it is easy to remove.

[0028] During actual use, in order to quickly inject fluid into the front blocking bag 14 and the rear blocking bag 12, the injection holes 15 on the central injection tube 11 located in the front blocking bag 13 and the rear blocking bag 12 are set to 1-10; when the number of injection holes 15 is two or more, they are generally distributed in a ring shape on the injection tube 11, and of course they can also be distributed in rows on the injection tube 11.

[0029] like Figure 1 As shown, the middle blocking bag 20, the front blocking bag 13 and the rear blocking bag 12 can be integrally formed by injection molding; of course, they can also be made in sections and then bonded together; on the one hand, the stability of the connection between the middle blocking bag 20 and the front blocking bag 13 and the rear blocking bag 12 is ensured, and on the other hand, the middle blocking bag 20 after connection is ensured to be located on the center line of the front blocking bag 13 and the rear blocking bag 12. The central injection tube 11 and the front blocking bag 13 and the rear blocking bag 12 are fixed by gluing, pressing rings or binding, as long as the central injection tube 11 and the front blocking bag 13 and the rear blocking bag 12 do not fall off.

[0030] like Figure 3 As shown, this embodiment exemplarily provides a hole wall coating and fissure grouting coordinated hole sealing method, using the gas extraction hole coating device of the above embodiment to perform hole wall coating and cooperate with fissure grouting to seal the hole, the specific steps are as follows:

[0031] S1: Insert the gas drainage hole injection device into the gas drainage hole 2 to a specified depth, so that the rear end of the rear plugging capsule 12 is at a distance L1 from the orifice of the gas drainage hole 2, and inject fluid into the rear plugging capsule 12, the middle plugging capsule 20, and the front plugging capsule 13 through the central injection pipe 11, so that the rear plugging capsule 12 and the front plugging capsule 13 are fully expanded so that the outer walls are in close contact with the inner wall of the gas drainage hole 2. After reaching a predetermined pressure, close the ball valve 18 on the central injection pipe 11;

[0032] S2: Quick-setting material is injected into the annular cavity 3 through the coating pipe 16 to form an annular coating layer 31 in the annular cavity 3; after the annular coating layer 31 is completely solidified, the fluid inside the rear plugging bladder 12, the middle plugging bladder 20, and the front plugging bladder 13 is released, so that the rear plugging bladder 12, the middle plugging bladder 20, and the front plugging bladder 13 are separated from the gas extraction hole 2 and the annular coating layer, and the coating device in the gas extraction hole is removed, and the annular coating layer 31 remains in the gas extraction hole 2, completing the hole wall coating;

[0033] S3: Use the grouting sealer to seal the gas extraction hole at the rear end of the hole wall coating, such as Figure 3 As shown, this embodiment exemplarily provides a conventional grouting sealer 4, after the gas extraction pipe 46 is fixed on the grouting sealer 4, it is inserted into the gas extraction hole 2, and the grouting sealer 4 forms three plugs in the gas extraction hole 2, namely the front end plug 43, the middle plug 42 and the rear end plug 41, the front end plug 43 is at a distance from the orifice of the gas extraction hole 2 not less than L1, the front end of the front end plug 43 is in close contact with the rear end of the annular injection coating layer 31, and a grouting cavity 44 and a plugging cavity 45 are respectively formed between the front end plug 43, the middle plug 42 and the rear end plug 41, and then the grouting cavity 44 and the plugging cavity 45 are grouted. After the grouting is completed, the material solidifies and the hole is sealed, and then the coal seam gas extraction can be started through the gas extraction pipe 46.

[0034] This embodiment achieves high-quality sealing of the gas extraction borehole by combining the coating device in the gas extraction hole with the conventional grouting and sealing method.

[0035] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. Any technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A hole wall coating and crack grouting coordinated hole sealing method, characterized in that: The hole wall is coated by a gas extraction hole coating device, and the hole is sealed in coordination with the fracture grouting. The gas extraction hole coating device includes a central injection pipe, and a plug is provided at the front end of the central injection pipe; the gas extraction hole coating device also includes a front plugging bag, a middle plugging bag and a rear plugging bag that are interconnected. The front end of the central injection pipe passes through the center of the rear plugging bag, the middle plugging bag and the front plugging bag in sequence. The front end of the front plugging bag is fixed to the outer wall of the central injection pipe, and the rear end of the rear plugging bag is fixed to the outer wall of the central injection pipe, and is located inside the front plugging bag and the rear plugging bag. The central injection pipe is provided with an injection hole for injecting fluid into the front plugging bag and the rear plugging bag. The outer diameter of the middle plugging bag is smaller than the outer diameters of the rear plugging bag and the front plugging bag after being filled with fluid. An annular cavity is formed between the front end of the rear plugging bag and the rear end of the front plugging bag after being filled with fluid and the outer wall of the middle plugging bag; an injection pipe for injecting quick-setting slurry into the annular cavity is provided through the front and rear end side walls of the rear plugging bag, and the ends of the central injection pipe and the injection pipe are both equipped with ball valves and pressure gauges; the hole wall injection coating-fracture grouting coordinated hole sealing method includes the following steps: S1: inserting the coating device into the gas extraction hole to a specified depth, so that the rear end of the rear plugging bag is L1 away from the orifice of the gas extraction hole, injecting fluid into the rear plugging bag, the middle plugging bag, and the front plugging bag through the central injection pipe, so that the rear plugging bag and the front plugging bag are fully expanded so that the outer walls are tightly attached to the inner wall of the gas extraction hole, and closing the ball valve on the central injection pipe after reaching a predetermined pressure; S2: Injecting quick-setting material into the annular cavity through the coating pipe to form an annular coating layer in the annular cavity; after the annular coating layer is completely solidified, the fluid inside the rear plugging bladder, the middle plugging bladder, and the front plugging bladder is released, so that the rear plugging bladder, the middle plugging bladder, and the front plugging bladder are separated from the gas extraction hole and the annular coating layer, and the coating device in the gas extraction hole is removed, and the annular coating layer remains in the gas extraction hole, completing the hole wall coating; S3: Insert a conventional grouting sealer into the gas extraction hole after the hole wall is coated. The distance between the front end of the grouting sealer and the mouth of the gas extraction hole is not less than L1. The front end of the grouting sealer is in close contact with the rear end of the annular coating layer. Then grouting is performed on the grouting sealer. After the grouting is completed, wait for the material to solidify and complete the hole sealing, and then coal seam gas extraction can begin.

2. The hole wall coating and crack grouting coordinated sealing method according to claim 1 is characterized in that: A layer of plastic film is pasted on the outer wall of the middle blocking sac, the front end side wall of the rear blocking sac, and the rear end side wall of the front blocking sac.

3. The hole wall coating and crack grouting coordinated sealing method according to claim 1 is characterized in that: The outer diameters of the rear plugging bladder and the front plugging bladder after being filled with fluid are the same. The axial lengths of the rear plugging bladder and the front plugging bladder are 0.5-1.0 m, and the length of the middle plugging bladder is 0.5-5 m.

4. The hole wall coating and crack grouting coordinated sealing method according to claim 1 is characterized in that: The number of injection holes on the central injection tubes in the front blocking bag and the rear blocking bag is set to 1-10.

5. The hole wall coating and crack grouting coordinated sealing method according to claim 1 is characterized in that: The central injection tube is fixed to the front blocking bag and the rear blocking bag by means of gluing, pressing ring or binding.

6. The hole wall coating and crack grouting coordinated sealing method according to claim 1 is characterized in that: The fluid injected into the front plugging bag and the rear plugging bag is downhole compressed air / high-pressure water.

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