Downhole directional in-seam gas extraction borehole protection structure and extraction device

Abstract

This utility model relates to the field of gas extraction technology, specifically to a borehole protection structure and extraction device for underground directional bedding gas extraction, mainly solving the technical problem of easy clogging of existing borehole protection pipes in underground directional bedding gas extraction. This borehole protection structure includes a double-layer perforated pipe and a double-layer solid pipe. The double-layer perforated pipe includes an outer perforated pipe and a first inner solid pipe. The double-layer solid pipe includes an outer solid pipe and a second inner solid pipe. During operation, air is blown sequentially through the second inner solid pipe and the first inner solid pipe towards the bottom of the borehole. Coal slag and accumulated water enter between the outer perforated pipe and the first inner solid pipe through the slag inlet hole of the outer perforated pipe, and then, driven by air pressure, are discharged to the outside of the borehole sequentially through the first slag discharge channel and the second slag discharge channel. This effectively avoids clogging of the borehole protection pipe, ensures extraction operation time, improves extraction efficiency, and also avoids the occurrence of abandoned boreholes due to clogging.

Description

Technical Field

[0001] This utility model relates to the field of gas extraction technology, and in particular to a borehole protection structure and extraction device for downhole directional in-seam gas extraction. Background Technology

[0002] Downhole directional gas extraction boreholes are generally downward-facing boreholes. After the borehole construction is completed, a protective casing needs to be inserted into the borehole to prevent borehole collapse.

[0003] The existing borehole protection pipes are all ordinary cylindrical pipes. Under the action of gravity, the coal slime in the borehole will be deposited at the bottom of the borehole, which will cause the protection pipe to be blocked, affecting the development of the extraction process, resulting in laborious construction and unsatisfactory extraction effect. Utility Model Content

[0004] To overcome the technical defects of existing downhole directional gas extraction borehole protection pipes that are prone to clogging, this utility model provides a downhole directional gas extraction borehole protection structure and extraction device.

[0005] The downhole directional in-seam gas extraction borehole protection structure provided by this utility model includes:

[0006] A double-layer tube includes an outer tube and a first inner solid tube. The outer tube has multiple slag inlet holes distributed on its wall. The first inner solid tube is coaxially sleeved inside the outer tube and is supported and fixed by a first pad block disposed between the outer tube and the first inner solid tube. An axially penetrating first slag discharge channel is formed between the first inner solid tube and the outer tube.

[0007] The double-layered solid pipe includes an outer solid pipe and a second inner solid pipe. The outer solid pipe is coaxially connected to the outer perforated pipe, and the second inner solid pipe is coaxially and sealed to the first inner solid pipe. A second gasket is provided between the outer solid pipe and the second inner solid pipe. An axially penetrating second slag discharge channel is formed between the second inner solid pipe and the outer solid pipe. The end of the outer solid pipe away from the outer perforated pipe is used to connect to the main pipe of the water pumping device, and the end of the second inner solid pipe away from the first inner solid pipe is used to lead out to the outside of the main pipe of the water pumping device.

[0008] Optionally, both the first pad and the second pad are rubber blocks.

[0009] Optionally, the end of the outer flower tube away from the outer solid tube is set as a tapered end.

[0010] Optionally, the first inner solid tube and the second inner solid tube are integrally formed.

[0011] Optionally, the outer perforated pipe, the outer solid pipe, the first inner solid pipe, and the second inner solid pipe are all PE pipes.

[0012] The underground directional in-seam gas extraction device provided by this utility model includes:

[0013] The aforementioned downhole directional in-seam gas extraction borehole protection structure, wherein the double-layer pipe is inserted into the bottom of the borehole;

[0014] A sealing structure is provided between the outer solid tube and the borehole opening to achieve a seal between the outer solid tube and the borehole;

[0015] A water pumping device includes a main pipe, one end of which is sealed to the outer solid pipe, and the other end of which serves as a pumping port to connect to pumping equipment and is equipped with a pumping valve. The lower part of the main pipe wall is provided with a slag outlet and a slag outlet valve.

[0016] An air inlet pipe has one end sealed to the second inner solid pipe, and the other end of the air inlet pipe is bent and sealed through the pipe wall of the main pipe. The air inlet pipe extends out of the end of the main pipe to form an air inlet and is equipped with an air inlet valve.

[0017] The technical solution provided by this utility model has the following advantages compared with the prior art:

[0018] The borehole protection structure for directional in-seam gas extraction provided by this utility model consists of a double-layer perforated pipe and a double-layer solid pipe. In use, the double-layer perforated pipe is installed inside the borehole with the bottom of the borehole positioned. The second inner solid pipe of the double-layer solid pipe is connected to the air inlet pipe. Air is blown sequentially through the second and first inner solid pipes to the bottom of the borehole. Coal slag and water enter between the outer perforated pipe and the first inner solid pipe through the slag inlet hole, and then, driven by air pressure, are discharged to the outside of the borehole sequentially through the first and second slag discharge channels. This effectively prevents blockage of the borehole protection pipe, ensuring extraction time, improving extraction efficiency, and also avoiding the occurrence of abandoned boreholes due to blockage.

[0019] The downhole directional gas extraction device provided by this utility model has the aforementioned advantages because it has the aforementioned downhole directional gas extraction hole protection structure. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the extraction device in an embodiment of the present invention.

[0023] In the picture:

[0024] 1. Double-layer perforated pipe; 11. Outer perforated pipe; 12. First inner solid pipe; 13. Slag inlet hole; 14. First pad block; 2. Double-layer solid pipe; 21. Outer solid pipe; 22. Second inner solid pipe; 23. Second pad block; 3. Sealing structure; 4. Pumping and draining device; 41. Main pipe; 42. Extraction port; 43. Extraction valve; 44. Slag outlet; 45. Slag outlet valve; 5. Air inlet pipe; 51. Air inlet; 52. Air inlet valve. Detailed Implementation

[0025] To better understand the above-mentioned objectives, features, and advantages of this utility model, the solution of this utility model will be further described below. It should be noted that, unless otherwise specified, the embodiments of this utility model and the features thereof can be combined with each other.

[0026] In this description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the present invention, and not all embodiments.

[0028] The following is combined with Figure 1 The specific embodiments of this utility model will be described in detail below. Example

[0029] This embodiment provides a downhole directional gas extraction borehole protection structure, including a double-layer perforated pipe 1 and a double-layer solid pipe 2.

[0030] The double-layer pipe 1 includes an outer pipe 11 and a first inner solid pipe 12. The outer pipe 11 has multiple slag inlet holes 13 distributed on its pipe wall. The first inner solid pipe 12 is coaxially sleeved on the inner side of the outer pipe 11 and is supported and fixed by a first pad 14 located between the outer pipe 11 and the first inner solid pipe 12. An axially penetrating first slag discharge channel is formed between the first inner solid pipe 12 and the outer pipe 11.

[0031] It is easy to understand that the only difference between a perforated pipe and a solid pipe is that a perforated pipe has multiple slag inlet holes 13 on its pipe wall, while a solid pipe has a solid pipe wall and no slag inlet holes 13.

[0032] Specifically, the material and size of the double-layer perforated pipe 1 are not limited. For example, in this embodiment, the outer perforated pipe 11 is designed as a 50mm PE pipe, and the first inner solid pipe 12 is designed as a 32mm PE pipe.

[0033] Specifically, the first pad 14 is a rubber block. During installation, the elasticity of the rubber block is used to insert it between the outer perforated tube 11 and the first inner solid tube 12. The first inner solid tube 12 is supported and fixed inside the outer perforated tube 11 by the cooperation of multiple rubber blocks.

[0034] It should be noted that since a first slag discharge channel needs to be formed between the first inner solid pipe 12 and the outer flower pipe 11, the first pad block 14 on any cross section cannot completely block the entire 360° circumference. A discrete arrangement is sufficient.

[0035] Specifically, the end of the outer perforated tube 11 furthest from the outer solid tube 21 is designed as a tapered end, which makes it easier for the outer perforated tube 11 to be inserted into the borehole.

[0036] The double-layer solid pipe 2 includes an outer solid pipe 21 and a second inner solid pipe 22. The outer solid pipe 21 is coaxially connected to the outer perforated pipe 11, and the second inner solid pipe 22 is coaxially and sealed to the first inner solid pipe 12. A second pad 23 is provided between the outer solid pipe 21 and the second inner solid pipe 22. An axially penetrating second slag discharge channel is formed between the second inner solid pipe 22 and the outer solid pipe 21. The end of the outer solid pipe 21 away from the outer perforated pipe 11 is used to connect to the main pipe 41 of the water pumping device 4, and the end of the second inner solid pipe 22 away from the first inner solid pipe 12 is used to lead out to the outside of the main pipe 41 of the water pumping device 4.

[0037] Specifically, the material and size of the double-layered solid tube 2 are not limited. For example, in this embodiment, the outer solid tube 21 is designed as a 50mm PE pipe, and the second inner solid tube 22 is designed as a 32mm PE pipe.

[0038] Specifically, the second pad 23 is a rubber block. During installation, the elasticity of the rubber block is used to insert it between the outer solid tube 21 and the second inner solid tube 22. The second inner solid tube 22 is supported and fixed inside the outer solid tube 21 by the cooperation of multiple rubber blocks.

[0039] It should be noted that since a second slag discharge channel needs to be formed between the second inner solid tube 22 and the outer solid tube 21, the second pad block 23 on any cross section cannot completely block the entire 360° circumference. A discrete arrangement is sufficient.

[0040] Specifically, the outer perforated tube 11 and the outer solid tube 21 can be connected and fixed using PVC glue or other common methods, and the sealing at the joint is not required.

[0041] Specifically, the first inner tube 12 and the second inner tube 22 are integrally formed, resulting in a more stable structure. Of course, a coupling or other commonly used structure can also be used to connect the first inner tube 12 and the second inner tube 22. However, regardless of the method used, the sealing between the second inner tube 22 and the first inner tube 12 must be ensured to guarantee the uniqueness of the pressure direction and the pressure magnitude during air intake.

[0042] The downhole directional gas extraction borehole protection structure of this embodiment needs to be used in conjunction with the sealing structure 3, the water extraction device 4 and the air supply pipe. For details on the specific working principle, please refer to Embodiment 2. Example

[0043] This utility model provides an underground directional in-seam gas extraction device, including the underground directional in-seam gas extraction hole protection structure described in Embodiment 1, and also includes a hole sealing structure 3, a water extraction device 4, and an air supply pipe.

[0044] Among them, the double-layered pipe 1 of the downhole directional gas extraction borehole protection structure is inserted into the bottom of the borehole. The double-layered pipe 1 is mainly used to support the extraction section inside the borehole, and the double-layered solid pipe 2 is mainly used to support the stress concentration section inside the borehole.

[0045] The sealing structure 3 is located between the outer solid tube 21 and the borehole opening and is used to achieve a seal between the outer solid tube 21 and the borehole.

[0046] It is easy to understand that the sealing structure 3 is mainly used to prevent the slag water from being discharged between the protective pipe and the borehole, thereby forcing the slag water to be discharged through the first slag discharge channel and the second slag discharge channel in sequence.

[0047] Specifically, cement or other commonly used sealing materials are used to fill the space between the outer solid pipe 21 and the borehole opening to form a sealing structure 3.

[0048] The water pumping device 4 includes a main pipe 41, one end of which is sealed to the outer solid pipe 21, and the other end of which serves as a pumping port 42 to connect to the pumping equipment and is equipped with a pumping valve 43. The lower part of the main pipe 41 is provided with a slag outlet 44 and a slag outlet valve 45.

[0049] It is easy to understand that the water pumping device 4 is a mature structure in this field, mainly used to achieve gas-liquid-solid separation, so that the gas is pumped away through the extraction port 42 and the coal slag water is discharged through the gate.

[0050] One end of the air inlet pipe 5 is sealed to the second inner solid pipe 22, and the other end of the air inlet pipe 5 is bent and sealed through the pipe wall of the main pipe 41. The air inlet pipe 5 extends out of the end of the main pipe 41 to form an air inlet 51 and is equipped with an air inlet valve 52.

[0051] It is easy to understand that the air inlet pipe 5 is connected to the second inner solid pipe 22 and sealed through the main pipe 41 so that the end of the second inner solid pipe 22 away from the first inner solid pipe 12 is used to lead out to the outside of the main pipe 41 of the water pumping device 4.

[0052] The working principle of the downhole directional in-seam gas extraction device in this embodiment is as follows:

[0053] In use, connect the air inlet 51 to the blowing equipment, the slag outlet 44 to the slag collection equipment, and the extraction port 42 to the extraction valve 43. When slag needs to be discharged, open the air inlet valve 52 and the slag outlet valve 45, and close the extraction valve 43. The coal slag water at the bottom of the borehole enters the first slag discharge channel through the slag inlet 13 under the action of air pressure, then reaches the main pipeline 41 of the water extraction device 4 through the second slag discharge channel, and finally is discharged into the slag collection equipment through the slag outlet 44. When there is no backflow of water or slag, close the air inlet valve 52 and the slag outlet valve 45, and open the extraction valve 43 for normal extraction.

[0054] In addition, this device can also be used for borehole collapse verification:

[0055] Connect the slag outlet 44 to the air blowing equipment, open the air inlet valve 52 and the slag outlet valve 45, and close the extraction valve 43. Whether airflow comes out of the air inlet 51 indicates whether the borehole is blocked or collapsed. If airflow comes out of the air inlet 51, the borehole is normal and there is no blockage. If no airflow comes out of the air inlet 51, the borehole is abnormal and there is blockage.

[0056] The above description is merely a specific embodiment of this utility model, enabling those skilled in the art to understand or implement it. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and all should be covered by the protection scope of the claims.

Claims

1. A borehole protection structure for downhole directional in-seam gas extraction, characterized in that, include: The double-layer tube (1) includes an outer tube (11) and a first inner solid tube (12). The outer tube (11) has multiple slag inlet holes (13) distributed on its wall. The first inner solid tube (12) is coaxially sleeved inside the outer tube (11) and supported and fixed by a first pad (14) between the outer tube (11) and the first inner solid tube (12). An axially penetrating first slag discharge channel is formed between the first inner solid tube (12) and the outer tube (11). The double-layer solid pipe (2) includes an outer solid pipe (21) and a second inner solid pipe (22). The outer solid pipe (21) is coaxially connected to the outer flower pipe (11), and the second inner solid pipe (22) is coaxially and sealed to the first inner solid pipe (12). A second pad (23) is provided between the outer solid pipe (21) and the second inner solid pipe (22). An axially penetrating second slag discharge channel is formed between the second inner solid pipe (22) and the outer solid pipe (21). The end of the outer solid pipe (21) away from the outer flower pipe (11) is used to connect to the main pipe (41) of the water pumping device (4), and the end of the second inner solid pipe (22) away from the first inner solid pipe (12) is used to lead out to the outside of the main pipe (41) of the water pumping device (4).

2. The downhole directional in-seam gas extraction borehole protection structure according to claim 1, characterized in that, Both the first pad (14) and the second pad (23) are rubber blocks.

3. The downhole directional in-seam gas extraction borehole protection structure according to claim 1, characterized in that, The end of the outer flower tube (11) away from the outer solid tube (21) is set as a tapered end.

4. The downhole directional in-seam gas extraction borehole protection structure according to claim 1, characterized in that, The first inner solid tube (12) and the second inner solid tube (22) are integrally formed.

5. The downhole directional in-seam gas extraction borehole protection structure according to any one of claims 1 to 4, characterized in that, The outer flower tube (11), outer solid tube (21), first inner solid tube (12), and second inner solid tube (22) are all PE pipes.

6. A downhole directional in-seam gas extraction device, characterized in that, include: The downhole directional gas extraction borehole protection structure according to any one of claims 1 to 5, wherein the double-layer pipe (1) is inserted into the bottom of the borehole; A sealing structure (3) is provided between the outer solid tube (21) and the borehole opening to achieve a seal between the outer solid tube (21) and the borehole. The water pumping device (4) includes a main pipe (41), one end of which is sealed to the outer solid pipe (21), the other end of which serves as a pumping port (42) to connect to the pumping equipment and is equipped with a pumping valve (43), and the lower part of the main pipe (41) is equipped with a slag outlet (44) and a slag outlet valve (45). An air inlet pipe (5) is sealed at one end to the second inner solid pipe (22). The other end of the air inlet pipe (5) is bent and sealed through the pipe wall of the main pipe (41). The air inlet pipe (5) extends out of the end of the main pipe (41) to form an air inlet (51) and is provided with an air inlet valve (52).

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