A helical progressive sealing tube and a sealing method thereof

Abstract

The application discloses a spiral progressive hole sealing pipe and a hole sealing method thereof, and the gas hole sealing and extraction work is carried out by coaxially connecting multiple spiral progressive hole sealing pipes. Since the maximum diameter of the spiral progressive thread piece of the spiral progressive hole sealing pipe is greater than the diameter of the drill hole, the spiral progressive thread piece can be embedded into the coal body of the hole wall during the rotation into the drill hole, and the hole sealing pipe and the drill hole are concentric circles. During the subsequent grouting sealing process, the flexible grouting pipe is rotated and pulled out along the spiral direction of the spiral progressive thread piece in the drill hole, so that the polyurethane high polymer foam material can be uniformly distributed between the hole sealing pipe and the hole wall of the drill hole. Meanwhile, due to the blocking effect of the spiral progressive thread piece, the polyurethane high polymer foam material expands in the spiral progressive thread piece. During the foaming and expanding process of the material, not only the pressure effect is generated in the axial direction of the drill hole, but also the pressure effect is generated in the radial direction of the drill hole, so that the hole sealing quality can be effectively improved, the air leakage condition can be reduced, and finally the gas extraction effect can be improved.

Description

Technical Field

[0001] This invention relates to a spiral progressive sealing pipe and its sealing method, which is particularly suitable for sealing the coal seam underground. Background Technology

[0002] With the increasing depth and intensity of coal mining, gas hazards have become a bottleneck restricting the achievement of high efficiency and high output in my country's mines. To ensure safe production, drilling and gas extraction from coal seams and goafs are effective measures to reduce coal seam gas content and gas emission from working faces. The gas extraction rate in my country's mines is generally low. Besides being affected by geological conditions such as the permeability coefficient of the coal seam, the main reason is that as drilling and gas extraction proceeds, cracks form between the sealing material and the borehole wall, causing severe air leakage and ultimately reducing the gas extraction concentration.

[0003] Currently, the sealing pipes used in various coal mines are mainly circular. The sealing process is as follows: first, a gas extraction borehole is drilled horizontally from the roadway wall into the coal seam; then, one end of the sealing pipe is inserted into the borehole, and polymer material or cement mortar is injected into the annular gap formed between the sealing pipe and the borehole. After the grouting material solidifies, the borehole is sealed. Because one end of the sealing pipe extends into the borehole, during the actual grouting process and before the grouting material solidifies, the sealing pipe, due to its own gravity, is closer to the lower borehole wall. That is, the axis of the sealing pipe is not coaxial with the axis of the borehole. The actual gap formed is an irregular annular shape (i.e., the gap between the sealing pipe and the upper borehole wall is larger, while the gap between the sealing pipe and the lower borehole wall is smaller). This results in an eccentric annular shape with less sealing material at the bottom and more sealing material at the top after grouting. After a period of gas drainage following borehole sealing, the borehole deforms under the influence of ground stress. Due to the limited amount of sealing material at the bottom of the borehole, its adhesion and friction with the borehole wall are insufficient, making it prone to cracking under external forces. During continued gas drainage, the negative pressure inside the borehole allows outside air to enter through these cracks, reducing the gas concentration and posing serious safety hazards to the gas drainage system and mine operations. Therefore, providing a sealing solution and method that effectively improves sealing quality, reduces the likelihood of cracks caused by ground stress during gas drainage, and ultimately improves gas drainage efficiency is one of the urgent technical problems to be solved in this industry. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a spiral progressive sealing pipe and its sealing method, which can effectively improve the sealing quality, reduce the possibility of cracks caused by ground stress during gas extraction, thereby reducing air leakage and ultimately improving the gas extraction effect.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a spiral progressive sealing tube, comprising a circular pipe and a spiral progressive thread plate;

[0006] The outer surface of the pipe wall near one end of the circular pipe is provided with external threads, and the inner surface of the pipe wall near the other end is provided with internal threads; the spiral progressive thread plate is fixed on the outer surface of the pipe wall of the circular pipe. The spiral progressive thread plate is composed of multiple thread plates of different diameters connected in sequence, so that the diameter of the spiral progressive thread plate on the outer surface of the pipe wall continuously increases from one end to the other.

[0007] Furthermore, the minimum diameter of the helical progressive thread plate is 0.85 to 0.95 times the borehole diameter, and the maximum diameter of the helical progressive thread plate is 1.1 to 1.2 times the borehole diameter.

[0008] Furthermore, the length of the circular pipe is 1.5 to 2.5 m, and the diameter of the circular pipe is 0.75 to 0.8 times the diameter of the borehole.

[0009] Furthermore, the pitch of the helical progressive thread plate is 10-20 cm, and the thickness of the helical progressive thread plate is 0.5-1.0 cm.

[0010] A sealing method using the above-mentioned spiral progressive sealing tube includes the following steps:

[0011] A. First, determine the diameter of the gas extraction borehole to be sealed. Based on the borehole diameter, select multiple spiral progressive sealing pipes of corresponding sizes. The specific selection criteria are as follows: the minimum diameter of the spiral progressive thread of the sealing pipe is 0.85 to 0.95 times the borehole diameter, the maximum diameter of the spiral progressive thread is 1.1 to 1.2 times the borehole diameter, and the diameter of the circular pipe is 0.75 to 0.8 times the borehole diameter; thus completing the selection process for the spiral progressive sealing pipe.

[0012] B. First, select one spiral progressive sealing pipe from step A. Position one end of the flexible grouting pipe at the minimum diameter of the spiral progressive thread plate. Then, wind the other end of the flexible grouting pipe sequentially around the circular pipe between adjacent thread plates along the spiral direction of the spiral progressive thread plate until the other end reaches the maximum diameter of the spiral progressive thread plate, completing the winding process of the spiral progressive sealing pipe. Next, with the end of the spiral progressive sealing pipe closest to the minimum diameter of the spiral progressive thread plate facing the borehole, rotate and feed it into the borehole. During the rotation, when the diameter of the spiral progressive thread plate is larger than the diameter of the borehole, the spiral progressive thread plate is continuously embedded into the coal body, while maintaining the circular pipe and the borehole as concentric circles, that is, the axis of the circular pipe and the axis of the borehole are coaxial. Continue until the maximum diameter of the spiral progressive thread plate of the spiral progressive sealing pipe reaches the borehole opening, at which point stop the rotation and feeding process of the spiral progressive sealing pipe.

[0013] C. Select another spiral progressive sealing pipe from step A, and thread it with the internal thread of the spiral progressive sealing pipe inside the borehole, making the circular pipes of the two spiral progressive sealing pipes coaxial, and the ends of the two spiral progressive sealing pipes closest to the minimum diameter of the spiral progressive thread plate facing the same direction; then, continue to wind the other end of the flexible grouting pipe along the spiral direction of the spiral progressive thread plate from the minimum diameter of the current spiral progressive sealing pipe onto the circular pipe between adjacent thread plates, until the other end reaches the spiral progressive thread. At the point of maximum diameter, the spiral progressive sealing tube is wound. Then, the spiral progressive sealing tube is rotated and fed in again until the maximum diameter of the spiral progressive thread of the second spiral progressive sealing tube reaches the borehole opening. The rotation feeding process is stopped, and this step is repeated until the total length of the spiral progressive sealing tube in the borehole is greater than the sealing depth. The rotation feeding process of the sealing tube is then completed. Then, the circular pipe tail of the last spiral progressive sealing tube is connected to the extraction pipe, and the other end of the flexible grouting pipe is extended outside the borehole and connected to the grouting pump.

[0014] D. During borehole sealing, the grouting pump is started to pump the polyurethane polymer foam material through the flexible grouting pipe to the minimum diameter of the spiral progressive thread plate of the deepest spiral progressive sealing pipe. During the injection process, the flexible grouting pipe is simultaneously pulled out of the borehole at a constant speed, so that the polyurethane polymer foam material is evenly distributed in the hollow positions formed between each adjacent spiral progressive thread plate and the borehole wall. Under the blocking effect of the spiral progressive thread plate, the polyurethane polymer material foams and solidifies in a relatively closed space. During the foaming and solidification process, a pressure effect is generated. After the polyurethane polymer foam material is completely solidified, the borehole sealing process is completed. At this time, the gas inside the borehole is extracted through the extraction pipe and circular pipeline.

[0015] Furthermore, in step D, the speed at which the flexible grouting pipe is pulled out of the borehole is the total length of the flexible grouting pipe inside the borehole divided by the grouting time.

[0016] Compared with existing technologies, this invention uses multiple spiral progressive sealing pipes coaxially connected for gas sealing and extraction. Because the maximum diameter of the spiral progressive thread of the sealing pipe is larger than the borehole diameter, it can embed itself into the coal seam within the borehole wall during its rotation into the borehole, maintaining the sealing pipe and borehole as concentric circles—that is, a standard annular gap between the sealing pipe and the borehole wall. During subsequent grouting for sealing, polyurethane polymer foam material is first delivered through a flexible grouting pipe to the lowest diameter point of the spiral progressive sealing pipe at the deepest point of the borehole, and then discharged outwards at a constant speed. The flexible grouting pipe is pulled out, and grout continues to be injected into the borehole from one end. During the pulling process, the flexible grouting pipe rotates along the helical direction of the spiral progressive threaded plate inside the borehole, allowing the polyurethane polymer foam material to be evenly distributed between the sealing pipe and the borehole wall. Simultaneously, due to the blocking effect of the spiral progressive threaded plate, multiple hollow positions formed between adjacent threaded plates and the borehole wall constitute a relatively closed space, causing the polyurethane polymer foam material to expand within it. During the foaming and expansion process, the material generates a pressure effect not only along the axial direction of the borehole but also in the radial direction. The former greatly enhances the density of the expanded sealing material, while the latter allows the sealing material to fully penetrate the cracks around the borehole, significantly improving the borehole's sealing performance. In addition, polyurethane polymer foam material can fix and seal the spiral progressive threaded plate inside the coal body, further improving the sealing effect, minimizing air leakage around the borehole, and ultimately ensuring a high concentration of gas extraction, thereby significantly improving the gas extraction effect. The entire structure and steps of this invention are simple, the implementation effect is good, and it has wide applicability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating a specific implementation of the present invention.

[0018] Figure 2 This is a schematic diagram of the spiral progressive sealing tube in this invention.

[0019] Figure 3 This is a schematic diagram of the structure of the suction tube in this invention.

[0020] In the diagram: 1. Spiral progressive sealing pipe; 1-1. External thread; 1-2. Circular pipe; 1-3. Spiral progressive threaded plate; 1-4. Internal thread; 2. Pulling pipe; 3. Flexible grouting pipe; 4. Drill hole; 5. Coal seam. Detailed Implementation

[0021] The present invention will be further described below.

[0022] like Figure 2 As shown, a spiral progressive sealing tube includes a circular pipe 1-2 and a spiral progressive threaded plate 1-3;

[0023] The circular pipe 1-2 has an external thread 1-1 on the outer surface of its wall near one end and an internal thread 1-4 on the inner surface of its wall near the other end. The spiral progressive thread plate 1-3 is fixed to the outer surface of the wall of the circular pipe 1-2. The spiral progressive thread plate is composed of multiple thread plates of different diameters connected in sequence, so that the diameter of the spiral progressive thread plate 1-3 continuously increases from one end to the other on the outer surface of the wall. The length of the circular pipe 1-2 is 1.5 to 2.5 m, the pitch of the spiral progressive thread plate 1-3 is 10 to 20 cm, and the thickness of the spiral progressive thread plate 1-3 is 0.5 to 1.0 cm.

[0024] like Figure 1 As shown, a sealing method for a spiral progressive sealing tube, comprising the following specific steps:

[0025] A. First, determine the diameter of the gas extraction borehole to be sealed. Based on the diameter of borehole 4, select multiple spiral progressive sealing pipes 1 of corresponding dimensions. The specific selection criteria are as follows: the minimum diameter of the spiral progressive thread plates 1-3 of the spiral progressive sealing pipe 1 is 0.85 to 0.95 times the borehole diameter, the maximum diameter of the spiral progressive thread plates 1-3 is 1.1 to 1.2 times the borehole diameter, and the diameter of the circular pipe 1-2 is 0.75 to 0.8 times the diameter of borehole 4; thus completing the selection process of the spiral progressive sealing pipe 1.

[0026] B. First, select one spiral progressive sealing tube 1 from step A. Position one end of the flexible grouting tube 3 at the minimum diameter of the spiral progressive thread plate 1-3. Then, wrap the other end of the flexible grouting tube 3 sequentially around the circular pipe 1-2 between adjacent thread plates along the spiral direction of the spiral progressive thread plate 1-3 until the other end reaches the maximum diameter of the spiral progressive thread plate 1-3. This completes the winding process of the spiral progressive sealing tube 1. Next, bring the spiral progressive sealing tube 1 close to the spiral progressive thread plate 1-3 at its maximum diameter. The smaller diameter end faces the borehole 4 and is rotated into the borehole 4. During the rotation, when the diameter of the spiral progressive threaded plate 1-3 is larger than the diameter of the borehole 4, the spiral progressive threaded plate 1-3 is continuously embedded into the coal body, while keeping the circular pipe 1-2 and the borehole 4 as concentric circles, that is, the axis of the circular pipe 1-2 is coaxial with the axis of the borehole 4; until the maximum diameter of the spiral progressive threaded plate 1-3 of the spiral progressive sealing pipe 1 reaches the opening of the borehole 4, at which point the rotation and feeding process of the spiral progressive sealing pipe 1 is stopped.

[0027] C. Select another spiral progressive sealing pipe 1 from step A, and thread it with its external thread 1-1 and the internal thread 1-4 of the spiral progressive sealing pipe 1 inside the borehole, so that the circular pipes 1-2 of the two spiral progressive sealing pipes 1 are coaxial, and the ends of the two spiral progressive sealing pipes 1 closest to the minimum diameter of the spiral progressive thread plate 1-3 face the same direction; then, let the other end of the flexible grouting pipe 3 continue to wind along the spiral direction of the spiral progressive thread plate 1-3 from the minimum diameter of the current spiral progressive sealing pipe 1 around the circular pipe 1-2 between the adjacent thread plates until the other end reaches the spiral... At the maximum diameter of the spiral progressive thread plate 1-3, the winding process of the spiral progressive sealing tube 1 is completed. At this time, the spiral progressive sealing tube 1 is rotated and fed in again until the maximum diameter of the spiral progressive thread plate 1-3 of the second spiral progressive sealing tube 1 reaches the opening of the borehole 4. The rotation and feeding process is stopped, and this step is repeated until the total length of the spiral progressive sealing tube 1 in the borehole 4 is greater than the sealing depth. The rotation and feeding process of the sealing tube is completed. Then, the tail of the circular pipe 1-2 of the last spiral progressive sealing tube 1 is connected to the extraction pipe 2, and the other end of the flexible grouting pipe 3 is extended outside the borehole and connected to the grouting pump.

[0028] D. During the sealing process, the grouting pump is started to pump the polyurethane polymer foam material through the flexible grouting pipe 3 to the minimum diameter of the spiral progressive thread plate 1-3 of the spiral progressive sealing pipe 1 at the deepest point. During the injection process, the flexible grouting pipe 3 is simultaneously pulled out of the borehole 4 at a constant speed. The specific speed is determined by dividing the total length of the flexible grouting pipe 3 inside the borehole 4 by the grouting time. This ensures that the polyurethane polymer foam material is evenly distributed in the hollow positions formed between each adjacent thread plate of the spiral progressive thread plate 1-3 and the borehole wall. Under the blocking effect of the spiral progressive thread plate 1-3, the polyurethane polymer material foams and solidifies in a relatively closed space. During the foaming and solidification process, a pressure effect is generated. After the polyurethane polymer foam material has completely solidified, the sealing process of the borehole is completed. At this time, the gas inside the borehole 4 is extracted through the extraction pipe 2 and the circular pipe 1-2.

[0029] As an improvement to this invention, in order to save on the amount of foaming material while ensuring the sealing effect, the total hollow volume formed between the spiral progressive sealing tube 1 and the borehole 4 can be calculated first using three-dimensional software. Then, the total volume is multiplied by 1.1 to 1.2 and divided by the foaming ratio of the foaming material to obtain the amount of polyurethane polymer material required to ensure the sealing effect. This injection amount not only ensures the sealing effect but also saves on the amount of foaming material.

[0030] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A sealing method for a spiral progressive sealing tube, characterized in that, The spiral progressive sealing pipe includes a circular pipe and a spiral progressive threaded plate; the outer surface of the pipe wall near one end has an external thread, and the inner surface of the pipe wall near the other end has an internal thread; the spiral progressive threaded plate is fixed to the outer surface of the pipe wall of the circular pipe, and the spiral progressive threaded plate is composed of multiple threaded plates of different diameters connected sequentially, so that the diameter of the spiral progressive threaded plate continuously increases from one end to the other on the outer surface of the pipe wall. The specific steps are as follows: A. First, determine the diameter of the gas extraction borehole to be sealed. Based on the borehole diameter, select multiple spiral progressive sealing pipes of corresponding sizes. The specific selection criteria are: the minimum diameter of the spiral progressive thread of the spiral progressive sealing pipe is 0.85 to 0.95 times the borehole diameter, the maximum diameter of the spiral progressive thread is 1.1 to 1.2 times the borehole diameter, and the diameter of the circular pipe is 0.75 to 0.8 times the borehole diameter; thus completing the selection process for the spiral progressive sealing pipe. B. First, select one spiral progressive sealing pipe from step A. Position one end of the flexible grouting pipe at the minimum diameter of the spiral progressive thread plate. Then, wind the other end of the flexible grouting pipe sequentially around the circular pipe between adjacent thread plates along the spiral direction of the spiral progressive thread plate until the other end reaches the maximum diameter of the spiral progressive thread plate, completing the winding process of the spiral progressive sealing pipe. Next, with the end of the spiral progressive sealing pipe closest to the minimum diameter of the spiral progressive thread plate facing the borehole, rotate and feed it into the borehole. During the rotation, when the diameter of the spiral progressive thread plate is larger than the diameter of the borehole, the spiral progressive thread plate is continuously embedded into the coal body, while maintaining the circular pipe and the borehole as concentric circles, that is, the axis of the circular pipe and the axis of the borehole are coaxial. Continue until the maximum diameter of the spiral progressive thread plate of the spiral progressive sealing pipe reaches the borehole opening, at which point stop the rotation and feeding process of the spiral progressive sealing pipe. C. Select another spiral progressive sealing pipe from step A, and thread it with the internal thread of the spiral progressive sealing pipe inside the borehole, making the circular pipes of the two spiral progressive sealing pipes coaxial, and the ends of the two spiral progressive sealing pipes closest to the minimum diameter of the spiral progressive thread plate facing the same direction; then, continue to wind the other end of the flexible grouting pipe along the spiral direction of the spiral progressive thread plate from the minimum diameter of the current spiral progressive sealing pipe onto the circular pipe between adjacent thread plates, until the other end reaches the spiral progressive thread. At the point of maximum diameter, the spiral progressive sealing tube is wound. Then, the spiral progressive sealing tube is rotated and fed in again until the maximum diameter of the spiral progressive thread of the second spiral progressive sealing tube reaches the borehole opening. The rotation feeding process is stopped, and this step is repeated until the total length of the spiral progressive sealing tube in the borehole is greater than the sealing depth. The rotation feeding process of the sealing tube is then completed. Then, the circular pipe tail of the last spiral progressive sealing tube is connected to the extraction pipe, and the other end of the flexible grouting pipe is extended outside the borehole and connected to the grouting pump. D. During borehole sealing, the grouting pump is started to pump the polyurethane polymer foam material through the flexible grouting pipe to the minimum diameter of the spiral progressive thread plate of the deepest spiral progressive sealing pipe. During the injection process, the flexible grouting pipe is simultaneously pulled out of the borehole at a constant speed, so that the polyurethane polymer foam material is evenly distributed in the hollow positions formed between each adjacent spiral progressive thread plate and the borehole wall. Under the blocking effect of the spiral progressive thread plate, the polyurethane polymer material foams and solidifies in a relatively closed space. During the foaming and solidification process, a pressure effect is generated. After the polyurethane polymer foam material is completely solidified, the borehole sealing process is completed. At this time, the gas inside the borehole is extracted through the extraction pipe and circular pipeline.

2. The sealing method for the spiral progressive sealing tube according to claim 1, characterized in that, The pitch of the spiral progressive threaded plate is 10-20cm, and the thickness of the spiral progressive threaded plate is 0.5-1.0cm.

3. The sealing method for the spiral progressive sealing tube according to claim 1, characterized in that, In step D, the speed at which the flexible grouting pipe is pulled out of the borehole is the total length of the flexible grouting pipe inside the borehole divided by the grouting time.

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