Directional long borehole continuous drainage and pumping device and method

Abstract

This invention discloses a directional long borehole continuous drainage and pumping device and method, relating to the field of underground gas extraction technology in coal mines. It includes a borehole protector, a drainage pipe, a drainage valve, and an extraction pipeline. The extraction pipeline is connected to the borehole protector. The interior of the borehole protector is connected to the drainage pipe via welding rods. The welding rods between the drainage pipe and the borehole protector are radially distributed, and multiple welding rods are axially distributed along the drainage pipe. The end of the drainage pipe is connected to the drainage valve. This invention employs the aforementioned directional long borehole continuous drainage and pumping device and method, which features automatic response without manual intervention. Material A and Material B can automatically switch forms according to the water accumulation state, requiring no manual judgment or operation. It adapts to complex drilling environments, especially suitable for deep long boreholes; the structure is stable and highly reliable.

Description

Technical Field

[0001] This invention relates to the field of underground gas extraction technology in coal mines, and in particular to a directional long borehole continuous drainage and extraction device and method. Background Technology

[0002] Directional long borehole drilling is one of the key technologies for underground gas drainage in coal mines. By drilling long-distance directional boreholes into the coal seam, large-area and efficient gas drainage can be achieved, which is of great significance for preventing gas accidents and utilizing resources. However, during the construction and drainage process of directional long boreholes, water often accumulates in the borehole due to groundwater seepage and coal seam seepage.

[0003] Accumulated water occupies borehole space, blocks gas flow channels, and increases gas extraction resistance, significantly reducing efficiency. Simultaneously, prolonged water retention exacerbates the risk of borehole wall collapse, shortening the effective service life of the borehole. Current technologies primarily rely on periodic manual cleaning or the installation of single drainage devices. Traditional drainage devices lack automatic response mechanisms, requiring manual assessment of water accumulation and operation, resulting in poor adaptability, especially unsuitable for long boreholes in deep or complex geological conditions. Therefore, developing a stable, directional, long borehole continuous drainage and pumping device and method that can automatically respond to water accumulation conditions is crucial to solving these problems. Summary of the Invention

[0004] The purpose of this invention is to provide a directional long borehole continuous drainage and pumping device and method, which realizes automatic identification and discharge of accumulated water, independent drainage and pumping, and stable and reliable structure.

[0005] To achieve the above objectives, the present invention provides a directional long borehole continuous drainage and pumping device, comprising a borehole protector, a drainage pipe, a drainage valve, and a pumping pipeline. The pumping pipeline is connected to the borehole protector. The interior of the borehole protector is connected to the drainage pipe via welding rods. Multiple welding rods are provided and are radially distributed along the drainage pipe. The end of the drainage pipe is connected to the drainage valve.

[0006] Preferably, the drain pipe is provided with a plurality of small holes, and a drain component is provided on the outside of the small holes. The drain component is fixed on the outside of the drain pipe by a hole control welding block. The drain component includes material A and material B, and both material A and material B are connected to the hole control welding block.

[0007] Preferably, the controlled hole welding block includes two opposing arc-shaped blocks, which are connected to material A and material B by bolts. The inner side of the arc-shaped block is in contact with the outer wall of the drain pipe, and the outer side of the arc-shaped block is provided with a limiting protrusion.

[0008] Preferably, material A is a highly cross-linked polyvinyl alcohol film, and material B is a low-cross-linked polyvinyl alcohol-sodium alginate composite film. The water swelling rate of material B is 1.5-3 times that of material A, and the thickness of material B is 1.2-2 times that of material A.

[0009] Preferably, the inner diameter of the drain pipe is smaller than the outer diameter of the protective hole pipe, an annular gap is formed between the protective hole pipe and the drain pipe, the welding rods are evenly distributed along the axial direction of the annular gap, one end of the welding rods is welded to the inner wall of the protective hole pipe, and the other end is welded to the outer wall of the drain pipe.

[0010] Preferably, the protective tube is provided with gas inlet holes, which are evenly distributed along the axial direction of the protective tube.

[0011] Preferably, the small holes are spaced apart along the axial direction of the drain pipe, and the axial distance between adjacent small holes is 5-10cm.

[0012] Preferably, the extraction pipeline and the extraction branch are connected by a T-joint, one end of the T-joint is connected to the extraction pipeline, the other end is connected to the extraction branch, and the third end is provided with a sealing cap.

[0013] A method for using a directional long borehole continuous drainage and pumping device includes the following steps:

[0014] S1. The device is installed and lowered into the directional long borehole so that the gas inlet of the protective pipe corresponds to the gas enrichment area in the channel.

[0015] S2. When there is no water in the borehole cavity, materials A and B naturally adhere to the outer wall of the drain pipe and seal the small hole. The gas in the borehole enters the annular gap between the borehole pipe and the drain pipe through the gas inlet hole, and is then extracted through the extraction pipeline and extraction branch.

[0016] S3. When water accumulates in the cavity of the protective hole, material B will bend first because its deformation coefficient is greater when it comes into contact with water, which will cause material A to bend synchronously, so that the hole opens and the accumulated water flows into the drain pipe through the hole.

[0017] S4. Open the drain valve and connect the negative pressure extraction equipment to allow the water in the drain pipe to be discharged through the extraction pipeline.

[0018] S5. After the water is drained, materials A and B are restored to their original state and the small hole is resealed. Repeat steps S2-S4 to achieve continuous drainage and pumping.

[0019] Preferably, during drainage in S4, the inner cavity of the protective pipe is connected to the drainage pipe, at which point gas extraction is stopped and the water accumulated in the pipe is discharged.

[0020] Therefore, the present invention employs the above-mentioned directional long borehole continuous drainage and pumping device and method, which has the following beneficial effects: automatic response, no need for manual intervention, materials A and B can automatically switch forms according to the water accumulation state without manual judgment or operation, adapting to complex drilling environments, especially suitable for deep long boreholes; stable structure, high reliability, welding rods and control hole welding blocks respectively limit the radial and axial displacement of the drainage pipe, ensuring long-term stable operation of the device and reducing the risk of borehole collapse.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an embodiment of a directional long borehole continuous drainage and pumping device according to the present invention;

[0023] Figure 2 This is a longitudinal sectional view of the tail section of a directional long borehole continuous drainage pumping device according to the present invention.

[0024] Figure 3 This is a longitudinal sectional view of the middle section of a directional long borehole continuous drainage and pumping device according to the present invention.

[0025] Figure 4 for Figure 3 Enlarged view of the structure at point C;

[0026] Figure 5 This is a longitudinal sectional view of the first section of a directional long borehole continuous drainage and pumping device according to the present invention.

[0027] Figure 6 This is a cross-sectional view of a directional long borehole continuous drainage and pumping device according to the present invention;

[0028] Figure 7 This is a schematic diagram of the water-filled structure of the drainage component of a directional long borehole continuous drainage and pumping device according to the present invention.

[0029] Figure Labels

[0030] 1. Protective pipe; 2. Drainage pipe; 3. Welding rod; 4. Drainage valve; 5. Gas inlet hole; 6. Material A; 7. Material B; 8. Control hole welding block; 9. Small hole; 10. Extraction pipeline; 11. Extraction branch. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0033] Example

[0034] Please see Figures 1-7 The present invention provides a directional long borehole continuous drainage and pumping device, including a borehole protection pipe 1, a drainage pipe 2, a welding rod 3, a drainage valve 4, a pumping pipeline 10, a pumping branch 11, material A6, material B7, and a borehole control welding block 8.

[0035] The protective casing 1 is the outer sleeve, coaxially installed in the directional long borehole of the coal body and distributed along the axial direction; multiple gas inlet holes 5 are uniformly provided along the axial direction of the protective casing 1, which are used for gas in the borehole to enter the annular gap between the protective casing 1 and the drainage pipe 2. The gas inlet holes 5 are strip-shaped holes uniformly distributed along the axial direction of the protective casing 1. The length direction of the strip-shaped holes is consistent with the axial direction of the protective casing 1, and the length of the strip-shaped holes is 5-15cm and the width is 2-5mm.

[0036] The drainage pipe 2 is an inner sleeve, coaxially inserted inside the protective pipe 1. Its outer diameter is smaller than the inner diameter of the protective pipe 1, and the two form an annular gap as a gas extraction channel. The middle section of the drainage pipe 2 has multiple small holes 9 along the axial direction and at axial intervals for water to flow in. The axial distance between adjacent small holes 9 is 5-10cm, and the diameter of each small hole 9 is 3-8mm.

[0037] Welding rod 3 is evenly distributed axially along the annular gap between the protective pipe 1 and the drain pipe 2. One end is welded to the inner wall of the protective pipe 1, and the other end is welded to the outer wall of the drain pipe 2. This is used to restrict the radial movement of the drain pipe 2 and ensure the coaxiality of the two.

[0038] Materials A6 and B7 are fixed to the outer wall of the drain pipe 2 outside the small hole 9. Materials A6 and B7 are arranged sequentially along the axial direction of the drain pipe 2 and fixed by a hole-controlling welding block 8. The hole-controlling welding block 8 consists of two opposing arc-shaped blocks, with the inner side fitting against the outer wall of the drain pipe 2 and the outer side having a limiting protrusion. Materials A6 and B7 are pressed tightly onto the drain pipe 2 by bolts to prevent axial displacement. The water expansion rate of material B7 is 1.5-3 times that of material A6, and the thickness of material B7 is 1-1.2 times that of material A6. The water deformation coefficient of material B7 is greater than that of material A6. When there is no water, they jointly seal the small hole 9. When there is water, the bending deformation of material B7 is greater, which causes material A6 to bend, thus opening the small hole 9.

[0039] Material A6 uses a highly cross-linked polyvinyl alcohol film with a thickness of 0.2-0.3 mm. This film uses polyvinyl alcohol with medium to high degree of polymerization and high degree of alcoholysis as the base material, and adds a high proportion of cross-linking agents such as glutaraldehyde, boric acid or epoxy compounds, which has a dense three-dimensional network structure. The high degree of cross-linking makes the polyvinyl alcohol film structurally stable in a dry environment and can effectively seal small pores 9. Its low hydrophilicity ensures low expansion rate and small deformation when exposed to water, and it is not easy to react with gas, water and other impurities. Material B7 uses a low-crosslinking polyvinyl alcohol-sodium alginate composite membrane with a thickness of 0.3-0.6 mm. This membrane uses polyvinyl alcohol as the base material, mixed with 30%-50% sodium alginate, and crosslinked with low-concentration crosslinking agents such as boric acid to form a thin film. When exposed to water, the carboxyl groups rapidly combine with water molecules, resulting in significant swelling. Polyvinyl alcohol provides structural support, and the low crosslinking degree allows the molecular chains to freely stretch due to hydration, resulting in uneven expansion along the thickness direction and bending deformation towards the non-expanded side. When drying, water molecules detach from the carboxyl groups of sodium alginate and the hydroxyl groups of polyvinyl alcohol, and the molecular chains re-contract and reset through hydrogen bonds, returning to their initial shape within 2-5 minutes. The crosslinked composite membrane is water-resistant and not easily dissolved, and can be repeatedly used in humid drilling environments.

[0040] The tail end of the drain pipe 2 extends out of the protective pipe 1 and is connected to the drain valve 4. The drain valve 4 is a ball valve, and the drain valve 4 is connected to the drain pipe 2 and the extraction pipeline 10 by threads. The extraction pipeline 10 is connected to the extraction branch 11 by a tee joint. One end of the tee joint is connected to the extraction pipeline 10, the other end is connected to the extraction branch 11, and the third end is equipped with a sealing cap. The extraction branch 11 is used for gas extraction, and the drain valve 4 is used to control the discharge of accumulated water.

[0041] A method for continuous drainage and pumping in directional long boreholes includes the following steps:

[0042] S1. Installation: Based on the diameter and depth of the directional long borehole, select suitable protective pipe 1 and drainage pipe 2. The length of protective pipe 1 should be slightly shorter than the borehole depth, and the length of drainage pipe 2 should match that of protective pipe 1. Gas inlet holes 5 are machined on protective pipe 1, with a group set every 1-2m along the axial direction, and each group having 4-6 evenly distributed strip holes circumferentially. Small holes 9 are machined in the middle section of drainage pipe 2 to ensure rapid water inflow. Materials A6 and B7 are sequentially attached to the area of ​​small hole 9 in drainage pipe 2, wrapped with the arc-shaped block of the hole-control welding block 8, and bolted in place to ensure complete material coverage of the small hole. 9. Insert the drainage pipe 2 into the protective pipe 1, and weld the welding rods 3 evenly in the annular gap between the two. The welding rods 3 are distributed radially, with a group of 4-6 rods every 50-100cm. Fix the coaxial position of the two. Connect the drainage valve 4, the extraction pipeline 10 and the tee joint in sequence at the tail section of the drainage pipe 2. Connect one end of the tee joint to the extraction branch 11 and seal the other end with a sealing cap. Close the drainage valve 4. Lower the assembled device into the directional long borehole, so that the gas inlet hole 5 of the first section corresponds to the coal seam gas enrichment area, and ensure that the gas can smoothly enter the annular gap.

[0043] S2. When there is no water in the gas extraction state: When there is no water in the annular gap between the borehole protector pipe 1 and the drainage pipe 2, materials A6 and B7 are in their natural state and jointly block the small hole 9 to prevent gas from entering the drainage pipe 2. At this time, the gas in the borehole enters the annular gap through the gas inlet hole 5 on the borehole protector pipe 5, flows along the gap to the tail section, and enters the negative pressure extraction equipment through the extraction pipeline 10 and the extraction branch 11 to realize gas extraction.

[0044] S3. Drainage with water present: When water seepage in the borehole causes water to accumulate in the cavity of the borehole casing 1, the accumulated water comes into contact with materials A6 and B7. Since the expansion rate and thickness of material B7 upon contact with water are greater than those of material A6, the bending deformation it produces after contact with water is significantly greater than that of material A6, forcing material A6 to undergo bending deformation simultaneously. Both materials detach from the outer wall of the drainage pipe 2, causing the small hole 9 to open. The accumulated water flows into the drainage pipe 2 through the small hole 9. At this time, the drainage valve 4 is opened, and the accumulated water in the drainage pipe 2 is discharged through the drainage valve 4 and the extraction pipeline 10. During the drainage process, the extraction branch 11 suspends extraction to prevent the accumulated water from entering the extraction branch.

[0045] S4. Cyclic Operation: After the accumulated water is drained, materials A6 and B7 are restored to their natural state, re-attached to the outer wall of the drainage pipe 2 and the small hole 9 is sealed; the drainage valve 4 is closed, the gas extraction branch 11 resumes gas extraction, and steps 2-3 are repeated to achieve continuous drainage and gas extraction.

[0046] Therefore, the present invention employs the above-mentioned directional long borehole continuous drainage and extraction device and method, which has the following beneficial effects: independent operation without interference; by utilizing the water-deformation characteristics of materials A and B, the small holes are automatically opened and closed, allowing drainage and gas extraction to proceed independently—the small holes are sealed to ensure unobstructed extraction channels when there is no water, and the small holes are opened to concentrate drainage when there is water, avoiding mutual interference; automatic response without manual intervention: materials A and B can automatically switch forms according to the water accumulation state, without manual judgment or operation, adapting to complex drilling environments, especially suitable for deep long boreholes; stable structure and high reliability: the welding rod and the hole control welding block respectively limit the radial and axial displacement of the drainage pipe, ensuring long-term stable operation of the device and reducing the risk of borehole collapse; simple operation and improved efficiency: after installation, the device can be operated cyclically without frequent disassembly or adjustment, significantly improving gas extraction efficiency and borehole service cycle.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A directional long borehole continuous drainage and pumping device, characterized by: It includes a protective pipe, a drainage pipe, a drainage valve, and an extraction pipeline. The extraction pipeline is connected to the protective pipe. The inside of the protective pipe is connected to the drainage pipe via welding rods. Multiple welding rods are provided and are radially distributed along the drainage pipe. The end of the drainage pipe is connected to the drainage valve. The drain pipe is provided with a plurality of small holes, and a drain component is provided on the outside of the small holes. The drain component is fixed on the outside of the drain pipe by a hole control welding block. The drain component includes material A and material B. Material A is provided on the outside of material B. Both material A and material B are connected to the hole control welding block. Material A is a highly cross-linked polyvinyl alcohol film, and material B is a low-cross-linked polyvinyl alcohol-sodium alginate composite film. The water swelling rate of material B is 1.5-3 times that of material A, and the thickness of material B is 1.2-2 times that of material A. The protective tube is provided with gas inlet holes, which are evenly distributed along the axial direction of the protective tube.

2. The directional long-hole continuous drainage and pre-extraction device according to claim 1, characterized in that: The controlled hole welding block includes two opposing arc-shaped blocks, which are connected to material A and material B by bolts. The inner side of the arc-shaped block is in contact with the outer wall of the drain pipe, and the outer side of the arc-shaped block is provided with a limiting protrusion.

3. The directional long borehole continuous drainage and pumping device according to claim 2, characterized in that: The inner diameter of the drain pipe is smaller than the outer diameter of the protective hole pipe. An annular gap is formed between the protective hole pipe and the drain pipe. The welding rods are evenly distributed along the axial direction of the annular gap. One end of the welding rod is welded to the inner wall of the protective hole pipe, and the other end is welded to the outer wall of the drain pipe.

4. The directional long borehole continuous drainage and pumping device according to claim 3, characterized in that: The small holes are spaced apart along the axial direction of the drain pipe, and the axial distance between adjacent small holes is 5-10cm.

5. The directional long borehole continuous drainage and pumping device according to claim 4, characterized in that: The extraction pipeline and the extraction branch are connected by a T-joint. One end of the T-joint is connected to the extraction pipeline, the other end is connected to the extraction branch, and the third end is provided with a sealing cap.

6. A method of using the directional long borehole continuous drainage and pumping device according to any one of claims 1-5, characterized in that, Includes the following steps: S1. The device is installed and lowered into the directional long borehole so that the gas inlet of the protective pipe corresponds to the gas enrichment area in the channel. S2. When there is no water in the borehole cavity, materials A and B naturally adhere to the outer wall of the drain pipe and block the small hole. The gas in the borehole enters the annular gap between the borehole pipe and the drain pipe through the gas inlet hole, and is then extracted through the extraction pipeline and extraction branch. S3. When water accumulates in the cavity of the protective hole, material B will bend first because its deformation coefficient is greater when it comes into contact with water, which will cause material A to bend synchronously, so that the hole opens and the accumulated water flows into the drain pipe through the hole. S4. Open the drain valve and connect the negative pressure extraction equipment to allow the water in the drain pipe to be discharged through the extraction pipeline. S5. After the water is drained, materials A and B are restored to their original state and the small hole is resealed. Repeat steps S2-S4 to achieve continuous drainage and pumping.

7. The method of using the directional long borehole continuous drainage and pumping device according to claim 6, characterized in that: When draining water in S4, the inner cavity of the protective pipe is connected to the drain pipe. At this time, gas extraction is stopped and the water accumulated in the pipe is discharged.

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