A high-expansion and high-resistance expansion casing type gas extraction sealing device and its use method

Abstract

The present invention relates to a high-expansion and high-resistance expansion sleeve type gas extraction and sealing device and a method for using the same, comprising a gas extraction pipe and a sealing device, wherein a first expansion sleeve is fixedly sleeved on the gas extraction pipe, the first expansion sleeve comprises a first inner sleeve and a first outer sleeve, and a gap is provided between the first outer sleeve and the first inner sleeve to form a first grouting space, a first water injection cavity is provided in the first inner sleeve, a first water injection pipe is fixedly connected in the first water injection cavity, and the first grouting space is fixedly connected with the first grouting pipe; a second expansion sleeve is also fixedly sleeved on the gas extraction pipe, the second expansion sleeve comprises a second inner sleeve and a second outer sleeve, and a gap is provided between the second outer sleeve and the second inner sleeve to form a second grouting space, a second water injection cavity is provided in the second inner sleeve, a second water injection pipe is fixedly connected in the second water injection cavity, and a second grouting pipe is fixedly connected in the second grouting space. When the present invention is used, it can ensure the sealing performance of the drilling hole and reduce safety hazards.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mining, and in particular relates to a high-expansion and high-resistance expansion casing type gas extraction and sealing device and a use method thereof. Background Art

[0002] Coal seam gas extraction is an effective means of preventing and utilizing coal mine gas. At present, before gas extraction, the borehole needs to be sealed. When sealing the borehole, the traditional method currently used is to use a hollow elastic bag to seal the hole. Specifically, the bag is fixed on the gas extraction pipe, and the gas extraction pipe is inserted into the borehole. The bag is expanded by injecting slurry into the bag. When the bag is expanded, it can be pressed against the wall of the borehole. When the bag is pressed against the wall of the borehole, it can support the wall of the borehole and seal it tightly. The borehole is sealed, but during the gas extraction process, high-pressure nitrogen or carbon dioxide or a mixed gas needs to be injected into the borehole to displace the gas in the coal seam. This places high demands on the sealing and safety performance of the borehole. The traditional bag has an elastic structure, so when used for a long time, the supporting force on the borehole wall will decrease, thereby reducing the sealing performance of the borehole, and there is a safety hazard that may cause an accident. It can no longer meet production needs. Therefore, there are still shortcomings and deficiencies in the existing technology. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-expansion and high-resistance expansion casing type gas extraction sealing device and a method of using the same, so as to solve the problems raised in the above background technology.

[0004] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0005] A high-expansion and high-resistance expansion sleeve type gas extraction and sealing device, comprising a gas extraction pipe, the gas extraction pipe comprising a head end and a tail end, the gas extraction pipe tail end fixed sleeve is provided with a sealing device arranged coaxially with the gas extraction pipe, the gas extraction pipe head end fixed sleeve is provided with a first expansion sleeve arranged coaxially with the gas extraction pipe, the first expansion sleeve is a double-layer hollow structure, the first expansion sleeve comprises a first inner sleeve fixedly sleeved on the gas extraction pipe and a first outer sleeve sleeved on the first inner sleeve, both ends of the first outer sleeve are fixedly connected to the first inner sleeve, and a gap is provided between the first outer sleeve and the first inner sleeve to form a first grouting space, the first inner sleeve has a cavity structure to form a first water injection cavity, the first water injection cavity is fixedly connected to a first water injection pipe penetrating the sealing device, and the first grouting space is fixedly connected to a first grouting pipe penetrating the sealing device;

[0006] The cam is secured to the cam face and is adapted to engage the first expansion pipe, the second expansion pipe being secured to the cam face and adapted to engage the first expansion pipe when the cam is engaged.

[0007] Furthermore, the first outer sleeve is fixedly connected to the outside of the first outer sleeve with a plurality of first protrusion structures that are equidistantly distributed along the circumference of the first outer sleeve and have the same length as the first outer sleeve, and a first groove structure is formed between every two adjacent first protrusion structures; each first protrusion structure is provided with a plurality of first liquid seepage holes that are equidistantly distributed along the length direction of the first protrusion structure.

[0008] Furthermore, there are multiple first expansion sleeves.

[0009] Furthermore, the second outer sleeve is fixedly connected to the outside with a plurality of second protrusion structures which are equidistantly distributed along the circumference of the second outer sleeve and have the same length as the second outer sleeve, and a second groove structure is formed between every two adjacent second protrusion structures; each second protrusion structure is provided with a plurality of second seepage holes equidistantly distributed along the length direction of the second protrusion structure at one end away from the sealing device; the pipe body of the first grouting pipe and the pipe body of the first water injection pipe are respectively located in the second groove structure.

[0010] Furthermore, the sealing device includes a gasket, a tray and a top sleeve which are sequentially sleeved on the gas extraction pipe, and the gasket is located on a side of the tray close to the second expansion sleeve.

[0011] Furthermore, a first grouting sleeve is installed at one end of the first grouting pipe away from the first expansion sleeve, a first water sealing sleeve is installed at one end of the first water injection pipe away from the first expansion sleeve, a second grouting sleeve is installed at one end of the second grouting pipe away from the second expansion sleeve, and a second water sealing sleeve is installed at one end of the second water injection pipe away from the second expansion sleeve.

[0012] Furthermore, the method for using the above-mentioned expandable casing type gas drainage sealing device includes the following steps:

[0013] Step 1: First, respectively sleeve the first expansion sleeve connected with the first water injection pipe and the first grouting pipe and the second expansion sleeve connected with the second water injection pipe and the second grouting pipe on the gas extraction pipe, and then fix the first expansion sleeve on the gas extraction pipe; secondly, according to the distance between the position of the first expansion sleeve and the borehole orifice, fix the second expansion sleeve on the gas extraction pipe, and make the first grouting pipe and the first water injection pipe pass through the second groove structure of the second expansion sleeve respectively; finally, sleeve the sealing device on the gas extraction pipe, and make the first grouting pipe, the first water injection pipe, the second grouting pipe and the second water injection pipe pass through the sealing device respectively, and seal the penetration position, then insert the gas extraction pipe into the borehole, and make the sealing device be located outside the borehole orifice;

[0014] Step 2: using a sealing device to seal the opening of the drilled hole;

[0015] Step 3: First, high-pressure water is injected into the first water injection cavity through the first water injection pipe. When the water injection pressure reaches a certain value, the first inner casing begins to expand and squeeze the first outer casing. When the water pressure exceeds the bearing limit of the first inner casing, the first outer casing will be permanently deformed and contact the borehole wall. Secondly, when the first outer casing contacts the borehole wall, water injection is stopped, and the water in the first water injection cavity is discharged outward through the first water injection pipe. Slurry is then injected into the first water injection cavity through the first water injection pipe to fill the first water injection cavity with slurry. Finally, the first water sealing jacket is installed to seal the first water injection pipe.

[0016] Step 4: Under the action of the first protruding structure, when the first inner casing expands under the influence of high-pressure water, the first grouting space will not be completely closed due to compression. At this time, grouting can be injected into the first grouting space through the first grouting pipe. After the grouting is completed, the first sealing sleeve is installed to close the first grouting pipe, completing the first sealing of the hole;

[0017] Step 5: First, grouting is performed into the second grouting space through the second grouting pipe. After the grouting is completed, the second grouting sleeve is installed to seal the second grouting pipe. Secondly, high-pressure water can be injected into the second water injection cavity through the second water injection pipe. When the water injection pressure reaches a certain value, the second inner casing begins to expand and squeeze the second outer casing. When the water pressure exceeds the bearing limit of the second inner casing, the second outer casing will be permanently deformed and contact the borehole wall. Finally, when the second outer casing contacts the borehole wall, water injection is stopped, and the water in the second water injection cavity is discharged outward through the second water injection pipe, and then slurry is injected into the second water injection cavity through the second water injection pipe to fill the second water injection cavity with slurry. Finally, the second water sealing sleeve is installed to seal the second water injection pipe to complete the second hole sealing.

[0018] Furthermore, in step four, when grouting is injected into the first grouting space through the first grouting pipe, the slurry may flow into the surrounding cracks of the borehole wall through the first liquid seepage holes.

[0019] Furthermore, in step five, when grouting is performed into the second grouting space through the second grouting pipe, the slurry can flow into the surrounding cracks of the borehole wall through the second seepage hole, and when the second outer casing is squeezed and expanded, the slurry outside the second expansion casing and the slurry in the second grouting space will be squeezed, so that the slurry in the second grouting space can flow into the surrounding cracks of the borehole wall through the second seepage hole again.

[0020] Furthermore, in step 2, when the sealing device seals the orifice of the drill hole, a plugging agent is used to seal the orifice of the drill hole, and the gasket, tray and top sleeve are tightly attached to the orifice of the drill hole for sealing.

[0021] By adopting the above technical solution, the present invention has the following beneficial effects:

[0022] The present invention is based on the existing gas extraction pipe and sealing device, and uses an expansion sleeve instead of a bag to seal the borehole. Specifically, in the initial state, the outer diameters of the first expansion sleeve and the second expansion sleeve are both smaller than the aperture of the borehole, which can facilitate the insertion of the gas extraction pipe into the borehole. When the first expansion sleeve expands, it will be permanently deformed and pressed against the wall of the borehole to seal the borehole once. Moreover, since the expanded first expansion sleeve is filled with slurry, the structural strength of the first expansion sleeve itself can be improved after the slurry solidifies, thereby increasing the support force on the borehole wall, thereby improving the support for the borehole. Sealing performance; in addition, when the second expansion sleeve expands, it will be permanently deformed and pressed against the wall of the borehole to perform a secondary sealing of the borehole. Moreover, since the second expansion sleeve is also filled with slurry after expansion, the structural strength of the second expansion sleeve itself can be improved after the slurry solidifies, thereby increasing the supporting force on the borehole wall to further improve the sealing performance of the borehole, thereby increasing the gas extraction volume. Compared with the prior art, the present invention will not reduce the supporting force of the sealing device on the borehole wall when used for a long time, thereby ensuring the sealing performance of the borehole to reduce safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 for Figure 1 Schematic diagram of the structure viewed from the AA direction;

[0025] Figure 3 for Figure 1 Schematic diagram of the structure in section along the BB direction;

[0026] Figure 4 for Figure 1 Schematic diagram of the structure viewed in the CC direction.

[0027] Figure numerals: 1. gas extraction pipe; 2. first expansion sleeve; 21. first inner sleeve; 22. first outer sleeve; 23. first grouting space; 24. first water injection cavity; 25. first protrusion structure; 26. first groove structure; 27. first seepage hole; 3. second expansion sleeve; 31. second inner sleeve; 32. second outer sleeve; 33. second grouting space; 34. second water injection cavity; 35. second protrusion structure; 36. second groove structure; 37. second seepage hole; 4. sealing device; 41. gasket; 42. tray; 43. top sleeve; 5. first water injection pipe; 51. first water sealing sleeve; 6. first grouting pipe; 61. first grouting sleeve; 7. second water injection pipe; 71. second water sealing sleeve; 8. second grouting pipe; 81. second grouting sleeve; 9. drilling hole. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and beneficial effects of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0029] like Figures 1 to 4As shown, the present invention provides a high-expansion and high-resistance expansion casing type gas extraction and sealing device, including a gas extraction pipe 1, the gas extraction pipe 1 includes a head end and a tail end, the tail end fixed sleeve of the gas extraction pipe 1 is provided with a sealing device 4 arranged coaxially with the gas extraction pipe 1, the gas extraction pipe 1 and the sealing device 4 are both existing technologies, and the sealing device 4 is used to seal the orifice position of the borehole 9; the head end fixed sleeve of the gas extraction pipe 1 is provided with a first expansion casing 2 arranged coaxially with the gas extraction pipe 1, in the initial state, the outer diameter of the first expansion casing 2 is smaller than the aperture of the borehole 9; the first expansion casing 2 is a double-layer hollow structure, the first expansion casing 2 includes a first inner casing 21 fixedly sleeved on the gas extraction pipe 1 and a first outer casing 22 sleeved on the first inner casing 21, both ends of the first outer casing 22 are fixedly connected to the first inner casing 21, and there is a gap between the first outer casing 22 and the first inner casing 21 to form a first grouting space 23, and the first inner casing 21 has a cavity structure A first water injection cavity 24 is formed, and a first water injection pipe 5 that passes through the sealing device 4 is fixedly connected in the first water injection cavity 24. The first water injection pipe 5 is used to first inject high-pressure water into the first water injection cavity 24. When the first expansion sleeve 2 expands, the high-pressure water is discharged and then used to fill the first water injection cavity 24 with slurry. In the process of injecting high-pressure water, the first inner sleeve 21 will expand and squeeze the first outer sleeve 22, and cause the first outer sleeve 22 to be permanently deformed so as to press against the wall of the borehole 9, thereby supporting the wall of the borehole 9 and sealing the borehole 9; a first grouting space 23 is fixedly connected with a first grouting pipe 6 that passes through the sealing device 4. When the first expansion sleeve 2 expands, the first grouting pipe 6 is used to fill the first grouting space 23 with slurry. Since the first water injection cavity 24 is also full of slurry, the slurry can fill the expanded first expansion sleeve 2, so that the structural strength of the first expansion sleeve 2 can be improved after the slurry solidifies.

[0030] Furthermore, a second expansion sleeve 3 is fixedly sleeved on the gas extraction pipe 1 between the sealing device 4 and the first expansion sleeve 2 and is coaxially arranged with the gas extraction pipe 1. In the initial state, the outer diameter of the second expansion sleeve 3 is smaller than the aperture of the borehole 9; the second expansion sleeve 3 is spaced apart from the first expansion sleeve 2, and the end of the second expansion sleeve 3 close to the sealing device 4 is in contact with the sealing device 4. The second expansion sleeve 3 is also a double-layer hollow structure. The second expansion sleeve 3 includes a fixed sleeve on the gas extraction pipe 1. The second inner sleeve 31 is connected to the second outer sleeve 32 which is sleeved on the second inner sleeve 31. The end of the second outer sleeve 32 away from the sealing device 4 is fixedly connected to the second inner sleeve 31. There is a gap between the second outer sleeve 32 and the second inner sleeve 31 to form a second grouting space 33. The second inner sleeve 31 has a cavity structure to form a second water injection cavity 34. The second water injection cavity 34 is fixedly connected with a second water injection pipe 7 which penetrates the sealing device 4. The second water injection pipe 7 is used to first inject high pressure into the second water injection cavity 34. When the second expansion sleeve 3 expands, the high-pressure water is discharged and then used to fill the second water injection cavity 34 with slurry. During the injection of high-pressure water, the second inner sleeve 31 expands and squeezes the second outer sleeve 32, causing the second outer sleeve 32 to deform permanently and press against the wall of the borehole 9, thereby supporting and sealing the borehole 9. The second grouting space 33 is fixedly connected to the second grouting pipe 8 that penetrates the sealing device 4. Before the second expansion sleeve 3 expands, the second The second grouting pipe 8 is used to fill the second grouting space 33 with slurry. After the second expansion sleeve 3 expands, the slurry in the second grouting space 33 can also fill the second grouting space 33 after being squeezed; since after the second expansion sleeve 3 expands, the second water injection cavity 34 is also filled with slurry, the slurry can fill the expanded second expansion sleeve 3, so that when the slurry solidifies, the structural strength of the second expansion sleeve 3 can be improved; the first grouting pipe 6 and the first water injection pipe 5 are respectively located outside the second expansion sleeve 3.

[0031] On the basis of the existing gas extraction pipe 1 and sealing device 4, the expansion sleeve replaces the bag to seal the borehole 9. Specifically, in the initial state, the outer diameters of the first expansion sleeve 2 and the second expansion sleeve 3 are both smaller than the aperture of the borehole 9, which can facilitate the insertion of the gas extraction pipe 1 into the borehole 9. When the first expansion sleeve 2 expands, it will be permanently deformed and will be pressed against the wall of the borehole 9 to seal the borehole 9. Moreover, since the expanded first expansion sleeve 2 is filled with slurry, the structural strength of the first expansion sleeve 2 itself can be improved after the slurry solidifies, thereby increasing the support force on the wall of the borehole 9, thereby improving the support for the borehole 9. The sealing performance of the borehole 9; in addition, when the second expansion sleeve 3 expands, it will be permanently deformed and pressed against the wall of the borehole 9 to perform a secondary sealing on the borehole 9. Moreover, since the second expansion sleeve 3 is also filled with slurry after expansion, the structural strength of the second expansion sleeve 3 itself can be improved after the slurry solidifies, thereby increasing the supporting force on the wall of the borehole 9, so as to further improve the sealing performance of the borehole, thereby increasing the gas extraction volume. Compared with the prior art, the present invention will not reduce the supporting force of the sealing device on the wall of the borehole 9 when used for a long time, thereby ensuring the sealing performance of the borehole 9 and reducing safety hazards.

[0032] During the gas extraction process, there are a large number of highly developed cracks around the borehole wall of the borehole 9, which will affect the sealing performance of the sealing device on the borehole 9 and cause the borehole 9 to collapse. Therefore, if Figure 1 and Figure 2 As shown, the first outer sleeve 22 is fixedly connected to a plurality of first protrusion structures 25 which are equidistantly distributed along the circumference of the first outer sleeve 22 and are of the same length as the first outer sleeve 22, and a first groove structure 26 is formed between every two adjacent first protrusion structures 25; each first protrusion structure 25 is provided with a plurality of first seepage holes 27 which are equidistantly distributed along the length direction of the first protrusion structure 25. Specifically, during use, after the first expansion sleeve 2 undergoes permanent deformation due to expansion, the first grouting pipe 6 is used to inject liquid into the first grouting space 23. The slurry is injected, and the first protrusion structure 25 is to ensure that the first grouting space 23 will not be completely closed due to squeezing after the first expansion sleeve 2 expands. In addition, in the process of injecting slurry into the first grouting space 23, the slurry can flow through the first seepage hole 27 to the surrounding cracks of the wall of the borehole 9 located at the position of the first expansion sleeve 2 and the first groove structure 26. At this time, the cracks around the wall of the borehole 9 will be tightly sealed, which can improve the sealing performance of the borehole 9 and prevent the borehole 9 from collapsing when the slurry solidifies.

[0033] Furthermore, there are multiple first expansion sleeves 2, and the multiple first expansion sleeves 2 are equidistantly distributed along the length direction of the gas extraction pipe 1. Specifically, each first expansion sleeve 2 is fixedly connected to a grouting pipe and a water injection pipe. The number of first expansion sleeves 2 can be determined according to the depth of the borehole 9 and the degree of development of cracks around the wall of the borehole 9, so as to seal the borehole 9 multiple times, thereby improving the sealing performance of the borehole 9. During use, the multiple first expansion sleeves 2 are used in sequence from the deep position of the borehole 9 to the shallow position of the borehole 9.

[0034] Further, if Figure 1 、 Figure 3 and Figure 4 As shown, the second outer sleeve 32 is fixedly connected to a plurality of second protrusion structures 35 which are equidistantly distributed along the circumference of the second outer sleeve 32 and are of the same length as the second outer sleeve 32, and a second groove structure 36 is formed between every two adjacent second protrusion structures 35; a plurality of second seepage holes 37 which are equidistantly distributed along the length direction of the second protrusion structure 35 are provided on the end of each second protrusion structure 35 away from the sealing device 4. Specifically, the length of the second expansion sleeve 3 is 2 to 3 meters, and the length of the second seepage holes 37 provided on the second expansion sleeve 3 is 1 to 1.5 meters. The appropriate length can be selected according to the degree of development of the cracks at different positions; in the process of use, since slurry is injected into the second grouting space 33 through the second grouting pipe 8 before the second expansion sleeve 3 expands and permanently deforms, the slurry is injected into the second grouting space 33. During the grouting process, the slurry can flow through the second seepage hole 37 to the surrounding cracks at the bottom of the borehole 9 wall at the position of the second expansion sleeve 3 and the second groove structure 36 at the top of the second expansion sleeve 3. In this way, when the second expansion sleeve 3 expands and deforms permanently, the second expansion sleeve 3 will compact the slurry outside the second expansion sleeve 3, such as squeezing the slurry in the second groove structure 36, and at the same time, squeeze the slurry in the second grouting space 33, so that the slurry in the second grouting space 33 can flow out again through the second seepage hole 37, so that the slurry can seal the cracks around the wall of the borehole 9 at this position tightly, so as to improve the sealing performance of the borehole 9, and when the slurry solidifies, it can also prevent the borehole 9 from collapsing; the pipe body of the first grouting pipe 6 and the pipe body of the first water injection pipe 5 are respectively located in the second groove structure 36.

[0035] The specific structure of the sealing device 4 is as follows: Figure 1 As shown, the sealing device 4 includes a gasket 41, a tray 42 and a top sleeve 43 which are sequentially mounted on the gas extraction pipe 1. The gasket 41 is located on the side of the tray 42 close to the second expansion sleeve 3. Specifically, when in use, a plugging agent is used to seal the opening of the borehole 9, and the gasket 41, the tray 42 and the top sleeve 43 are tightly attached to the opening of the borehole 9 for sealing.

[0036] Further, such as Figure 1 As shown, the first grouting pipe 6 is provided with a first grouting sleeve 61 at one end away from the first expansion sleeve 2, and the first grouting sleeve 61 is used to close the first grouting pipe 6; the first water injection pipe 5 is provided with a first water sealing sleeve 51 at one end away from the first expansion sleeve 2, and the first water sealing sleeve 51 is used to close the first water injection pipe 5; the second grouting pipe 8 is provided with a second grouting sleeve 81 at one end away from the second expansion sleeve 3, and the second grouting sleeve 81 is used to close the second grouting pipe 8; the second water injection pipe 7 is provided with a second water sealing sleeve 71 at one end away from the second expansion sleeve 3, and the second water sealing sleeve 71 is used to close the second water injection pipe 7.

[0037] Furthermore, the method for using the high-expansion and high-resistance expansion casing type gas drainage and sealing device comprises the following steps:

[0038] Step 1: First, the first expansion sleeve 2 connected with the first water injection pipe 5 and the first grouting pipe 6 and the second expansion sleeve 3 connected with the second water injection pipe 7 and the second grouting pipe 8 are respectively mounted on the gas extraction pipe 1, and then the first expansion sleeve 2 is fixed on the gas extraction pipe 1. The position of the first expansion sleeve 2 on the gas extraction pipe 1 can be selected according to the previously determined coal seam geological conditions and the degree of development of the fissures around the borehole wall. The first expansion sleeve 2 is located at the fully developed position of the fissures around the borehole wall of the borehole 9. In the initial state, the outer diameters of the first expansion sleeve 2 and the second expansion sleeve 3 are both smaller than the borehole wall. The aperture of the hole 9; secondly, according to the distance between the position of the first expansion sleeve 2 and the orifice of the borehole 9, the second expansion sleeve 3 is fixed on the gas extraction pipe 1, and the first grouting pipe 6 and the first water injection pipe 5 are respectively passed through the second groove structure 36 of the second expansion sleeve 3; finally, a sealing device 4 is set on the gas extraction pipe 1, and the first grouting pipe 6, the first water injection pipe 5, the second grouting pipe 8 and the second water injection pipe 7 are respectively passed through the sealing device 4 and the penetration position is sealed, and then the gas extraction pipe 1 is inserted into the borehole 9, and the sealing device 4 is located outside the orifice of the borehole 9, completing the installation of the gas extraction pipe 1;

[0039] Step 2: After the gas extraction pipe 1 is installed, the opening of the borehole 9 is sealed using the sealing device 4 to complete the sealing of the opening of the borehole 9;

[0040] Step 3: After the orifice position of the borehole 9 is sealed, first, high-pressure water is injected into the first water injection cavity 24 through the first water injection pipe 5. When the water injection pressure reaches a certain value, the first inner casing 21 begins to expand and squeeze the first outer casing 22. When the water pressure exceeds the bearing limit of the first inner casing 21, the first outer casing 22 will be permanently deformed and contact the borehole wall; secondly, when the first outer casing 22 contacts the borehole wall, water injection is stopped, and the water in the first water injection cavity 24 is discharged outward through the first water injection pipe 5, and then slurry is injected into the first water injection cavity 24 through the first water injection pipe 5, so that the slurry fills the first water injection cavity 24; finally, the first water sealing jacket 51 is installed to close the first water injection pipe 5, so that the slurry fills the expanded first inner casing 21;

[0041] Step 4: Under the action of the first protruding structure 25, when the first inner casing 21 expands under the influence of high-pressure water, the first grouting space 23 will not be completely closed due to compression. At this time, grouting can be injected into the first grouting space 23 through the first grouting pipe 6, and the grouting amount can be controlled according to the degree of development of cracks around the wall of the borehole 9. After the grouting is completed, the first sealing sleeve 61 is installed to close the first grouting pipe 6, completing the first hole sealing. At this time, the slurry will fill the first grouting space 23. Since the first water injection cavity 24 is also full of slurry, the slurry can fill the expanded first expansion casing 2, so that the structural strength of the first expansion casing 2 can be improved after the slurry solidifies.

[0042] Step 5: First, grouting is performed into the second grouting space 33 through the second grouting pipe 8, and the grouting amount is controlled according to the degree of development of the cracks around the wall of the borehole 9. After the grouting is completed, the second grouting sleeve 81 is installed to close the second grouting pipe 8 so that the slurry fills the second grouting space 33; secondly, high-pressure water can be injected into the second water injection cavity 34 through the second water injection pipe 7. When the water injection pressure reaches a certain value, the second inner casing 31 begins to expand and squeeze the second outer casing 32. When the water pressure exceeds the bearing limit of the second inner casing 31, the second outer casing 32 will be permanently deformed and contact the borehole wall; finally, when the second outer casing 32 contacts the borehole wall, Stop water injection, and discharge the water in the second water injection cavity 34 outward through the second water injection pipe 7, and then inject slurry into the second water injection cavity 34 through the second water injection pipe 7 to fill the second water injection cavity 34 with slurry; finally, install the second water sealing sleeve 71 to close the second water injection pipe 7 to complete the second sealing; at this time, the slurry will fill the expanded second inner sleeve 31, and after the second outer sleeve 32 is squeezed and deformed, the slurry in the second grouting space 33 can also fill the second grouting space 33 after being squeezed, so that the slurry can fill the expanded second expansion sleeve 3, so that the structural strength of the second expansion sleeve 3 can be improved after the slurry solidifies.

[0043] Furthermore, in step four, when grouting is performed into the first grouting space 23 through the first grouting pipe 6, the slurry can flow into the cracks around the wall of the borehole 9 through the first seepage hole 27. At this time, the cracks around the wall of the borehole 9 at the position of the first expansion sleeve 2 will be tightly sealed to improve the sealing performance of the borehole 9, and when the slurry solidifies, it can also prevent the borehole 9 from collapsing.

[0044] Furthermore, in step five, when grouting is performed into the second grouting space 33 through the second grouting pipe 8, the slurry can flow into the surrounding cracks of the borehole 9 wall through the second seepage hole 37, and when the second outer sleeve 32 is squeezed and expanded, it will squeeze the slurry outside the second expansion sleeve 3 and the slurry in the second grouting space 33, so that the slurry in the second grouting space 33 can flow into the surrounding cracks of the borehole 9 wall through the second seepage hole 37 again. At this time, the cracks around the borehole 9 wall at the position of the second expansion sleeve 3 will be sealed tightly to improve the sealing performance of the borehole 9, and when the slurry solidifies, it can also prevent the borehole 9 from collapsing.

[0045] Furthermore, in step 2, when the sealing device 4 seals the opening of the borehole 9, a plugging agent is used to seal the opening of the borehole 9, and the gasket 41, the tray 42 and the top sleeve 43 are tightly attached to the opening of the borehole 9 for sealing.

[0046] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications are possible without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the claimed invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-expansion, high-resistance expansion casing-type gas extraction and sealing device, comprising a gas extraction pipe, the gas extraction pipe comprising a head end and a tail end, the tail end fixing sleeve of the gas extraction pipe being provided with a sealing device coaxially arranged with the gas extraction pipe, characterized in that: The head end of the gas extraction pipe is fixedly sleeved with a first expansion sleeve arranged coaxially with the gas extraction pipe, the first expansion sleeve is a double-layer hollow structure, the first expansion sleeve includes a first inner sleeve fixedly sleeved on the gas extraction pipe and a first outer sleeve sleeved on the first inner sleeve, both ends of the first outer sleeve are fixedly connected to the first inner sleeve, and a gap is provided between the first outer sleeve and the first inner sleeve to form a first grouting space, the first inner sleeve has a cavity structure to form a first water injection cavity, the first water injection cavity is fixedly connected to a first water injection pipe that penetrates the sealing device, and the first grouting space is fixedly connected to a first grouting pipe that penetrates the sealing device; The first outer sleeve is fixedly connected to a plurality of first protrusion structures equidistantly distributed along the circumference of the first outer sleeve and having the same length as the first outer sleeve, with a first groove structure formed between every two adjacent first protrusion structures; each first protrusion structure is provided with a plurality of first liquid permeation holes equidistantly distributed along the length direction of the first protrusion structure; when the first expansion sleeve is expanded, it will be permanently deformed; The cam is secured to the cam face of the second expansion sleeve and is adapted to engage the first expansion sleeve and engage with the second expansion sleeve when the cam is engaged. The second outer sleeve is fixedly connected to the outside with a plurality of second protrusion structures which are equidistantly distributed along the circumference of the second outer sleeve and have the same length as the second outer sleeve, and a second groove structure is formed between every two adjacent second protrusion structures; each second protrusion structure is provided with a plurality of second liquid seepage holes equidistantly distributed along the length direction of the second protrusion structure at one end away from the sealing device; the pipe body of the first grouting pipe and the pipe body of the first water injection pipe are respectively located in the second groove structure; and permanent deformation will occur when the second expansion sleeve expands.

2. A high expansion and high resistance expansion casing type gas drainage and sealing device according to claim 1, characterized in that: There are multiple first expansion sleeves.

3. The high expansion and high resistance expansion casing type gas drainage and sealing device according to claim 1, characterized in that: The sealing device comprises a gasket, a tray and a top sleeve which are sequentially sleeved on the gas extraction pipe, and the gasket is located on a side of the tray close to the second expansion sleeve.

4. The high expansion and high resistance expansion casing type gas drainage and sealing device according to claim 3, characterized in that: A first grouting sleeve is installed at one end of the first grouting pipe away from the first expansion sleeve, a first water sealing sleeve is installed at one end of the first water injection pipe away from the first expansion sleeve, a second grouting sleeve is installed at one end of the second grouting pipe away from the second expansion sleeve, and a second water sealing sleeve is installed at one end of the second water injection pipe away from the second expansion sleeve.

5. A method for using the high-expansion and high-resistance expansion casing type gas drainage and sealing device according to claim 4, characterized in that: The steps include: Step 1: First, respectively sleeve the first expansion sleeve connected with the first water injection pipe and the first grouting pipe and the second expansion sleeve connected with the second water injection pipe and the second grouting pipe on the gas extraction pipe, and then fix the first expansion sleeve on the gas extraction pipe; secondly, according to the distance between the position of the first expansion sleeve and the borehole orifice, fix the second expansion sleeve on the gas extraction pipe, and make the first grouting pipe and the first water injection pipe pass through the second groove structure of the second expansion sleeve respectively; finally, sleeve the sealing device on the gas extraction pipe, and make the first grouting pipe, the first water injection pipe, the second grouting pipe and the second water injection pipe pass through the sealing device respectively, and seal the penetration position, then insert the gas extraction pipe into the borehole, and make the sealing device be located outside the borehole orifice; Step 2: using a sealing device to seal the opening of the drilled hole; Step 3: First, high-pressure water is injected into the first water injection cavity through the first water injection pipe. When the water injection pressure reaches a certain value, the first inner casing begins to expand and squeeze the first outer casing. When the water pressure exceeds the bearing limit of the first inner casing, the first outer casing will be permanently deformed and contact the borehole wall. Secondly, when the first outer casing contacts the borehole wall, water injection is stopped, and the water in the first water injection cavity is discharged outward through the first water injection pipe. Slurry is then injected into the first water injection cavity through the first water injection pipe to fill the first water injection cavity with slurry. Finally, the first water sealing jacket is installed to seal the first water injection pipe. Step 4: Under the action of the first protruding structure, when the first inner casing expands under the influence of high-pressure water, the first grouting space will not be completely closed due to compression. At this time, grouting is injected into the first grouting space through the first grouting pipe. After the grouting is completed, the first sealing sleeve is installed to seal the first grouting pipe, completing the first sealing of the hole; Step 5: First, grouting is performed into the second grouting space through the second grouting pipe. After the grouting is completed, the second grouting sleeve is installed to seal the second grouting pipe. Secondly, high-pressure water is injected into the second water injection cavity through the second water injection pipe. When the water injection pressure reaches a certain value, the second inner casing begins to expand and squeeze the second outer casing. When the water pressure exceeds the bearing limit of the second inner casing, the second outer casing will be permanently deformed and contact the borehole wall. Finally, when the second outer casing contacts the borehole wall, water injection is stopped, and the water in the second water injection cavity is discharged outward through the second water injection pipe, and then slurry is injected into the second water injection cavity through the second water injection pipe to fill the second water injection cavity with slurry. Finally, the second water sealing sleeve is installed to seal the second water injection pipe to complete the second hole sealing.

6. The method for using the high-expansion and high-resistance expansion casing type gas drainage and sealing device according to claim 5, characterized in that: In step 4, when grouting is injected into the first grouting space through the first grouting pipe, the slurry flows into the surrounding cracks of the borehole wall through the first liquid seepage holes.

7. The method for using the high-expansion and high-resistance expansion casing type gas drainage and sealing device according to claim 5, characterized in that: In step five, when grouting is performed into the second grouting space through the second grouting pipe, the slurry flows into the surrounding cracks of the borehole wall through the second seepage hole, and when the second outer casing is squeezed and expanded, the slurry outside the second expansion casing and the slurry in the second grouting space are squeezed, so that the slurry in the second grouting space flows into the surrounding cracks of the borehole wall through the second seepage hole again.

8. The method for using the high-expansion and high-resistance expansion casing type gas drainage and sealing device according to claim 5, characterized in that: In step 2, when the sealing device seals the orifice of the drilled hole, a plugging agent is used to seal the orifice of the drilled hole, and the gasket, tray and top sleeve are tightly attached to the orifice of the drilled hole for sealing.

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