Segmented repressing floral tube for gas extraction of soft coal seam and use method of segmented repressing floral tube

Abstract

The soft coal seam gas extraction sectional type pressure supplementing perforated pipe comprises a perforated pipe body, a plurality of gas flowing holes which are through inside and outside are formed in the outer circle of the perforated pipe body, a pressure supplementing pipe is axially arranged on the inner wall of the perforated pipe body, and the pressure supplementing pipe and the perforated pipe body are integrally formed in an extrusion mode. The front end of the pressure supplementing pipe is integrally provided with an outer protruding pipe connector extending out of the front end opening of the floral pipe body, the rear end of the pressure supplementing pipe is integrally provided with an inner concave pipe connector matched with the outer protruding pipe connector, and the rear end of the inner concave pipe connector is flush with the rear end of the floral pipe body. The device is scientific in principle and simple in structure, through the design of the pressure supplementing pipe on the inner wall of the floral pipe body, the problem of in-hole negative pressure attenuation caused by drill hole deformation or hole collapse is effectively solved, it is guaranteed that under the drill hole collapse condition, reasonable extraction negative pressure exists in a hole, the effective extraction length is increased, and therefore the gas extraction efficiency is effectively improved; and safe and efficient mining of coal mines is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of gas extraction from soft protruding coal seams or soft rock strata, and specifically relates to a segmented pressure-replenishing flower pipe for gas extraction from soft coal seams and a use method thereof. Background Art

[0002] In the process of underground gas extraction, in order to ensure the normal and efficient gas extraction, it is necessary to ensure that the extraction negative pressure is constant and the effective extraction length remains unchanged. At present, after the drilling construction, the borehole is very likely to collapse under the action of high stress and high gas pressure, which seriously affects the gas extraction effect of the borehole. The widely used soft coal seam screen pipe (flower pipe) hole protection technology often causes the collapsed coal body in the hole to block the screen pipe, such as Figure 1 As shown in the figure, the screen tube protection hole fails, the actual effective extraction length of the borehole is difficult to guarantee, and it cannot solve the problem of negative pressure attenuation in extraction. If the negative pressure attenuation in the borehole and the effective extraction length problem cannot be dealt with in time, it will seriously affect the gas extraction efficiency, produce extraction blank zones, cause extraction engineering waste, and greatly limit the progress of gas extraction reaching the standard, and increase the risk of gas disasters during coal mining. Therefore, conventional flower tubes and screen tubes do not solve the problems of negative pressure attenuation in the borehole and the effective extraction length, and a new flower tube needs to be developed urgently. Summary of the invention

[0003] In order to address the deficiencies in the prior art, the present invention provides a segmented pressure-replenishing flower pipe for gas extraction from soft coal seams and a method of using the same, which effectively solves the problem of negative pressure attenuation in the hole caused by borehole deformation or borehole collapse, ensures that there is a reasonable extraction negative pressure in the hole in the event of borehole collapse, increases the effective extraction length, and thereby effectively improves the gas extraction efficiency and promotes safe and efficient mining in coal mines.

[0004] In order to solve the above technical problems, the present invention adopts the following technical scheme: a segmented pressure-boosting flower pipe for gas extraction from soft coal seams, comprising a flower pipe body, a plurality of gas flow holes which are transparent inside and outside are opened on the outer circle of the flower pipe body, a pressure-boosting pipe is axially arranged on the inner wall of the flower pipe body, the pressure-boosting pipe and the flower pipe body are extruded integrally, a convex pipe joint extending out of the front port of the flower pipe body is integrally provided at the front end of the pressure-boosting pipe, an inner concave pipe joint matched with the outer convex pipe joint is integrally provided at the rear end of the pressure-boosting pipe, and the rear end of the inner concave pipe joint is flush with the rear end of the flower pipe body.

[0005] The outer circle interference sleeve of the external convex pipe joint is provided with a rubber sealing ring.

[0006] The outer circle of the convex pipe joint is provided with an overall annular oblique groove, the opening of the oblique groove faces the port of the flower tube body, and the inner circle of the concave pipe joint is provided with a barbed convex ring that is integrally matched with the oblique groove.

[0007] The method for using the segmented pressure-replenishing flower pipe for gas extraction in soft coal seams is to use the segmented pressure-replenishing flower pipe for gas extraction in soft coal seams for operation, including the following steps: (1) The number of sections of the extraction borehole is determined as n according to the coal rock solidity coefficient f at the construction site; (2) The area near the hole mouth and the hole bottom of the entire extraction borehole is divided into the hole bottom section and the hole mouth section respectively. The hole bottom section adopts a flower tube without an internal pressure-boosting tube, and the inner concave pipe joints and / or outer convex pipe joints at both ends of the flower tube without a pressure-boosting tube are retained; the principle of connecting the flower tubes in series is: the number of pressure-boosting tubes in the flower tubes used from the hole bottom section to the hole mouth section increases by one successively; (3) According to the number of segments n of the extraction borehole, different numbers of flower tubes of the booster pipe are connected in sequence. The flower tube of the borehole mouth section passes through the extraction pipe and is connected to the elbow joint. The elbow joint passes through the extraction pipe and is connected to the extraction main road through the extraction branch road. The outer port of the extraction pipe is connected to the extraction main road. (4) The gas inside the extraction borehole is extracted, and the extraction branch uses the pressure-boosting pipe to supplement the pressure in each section of the extraction borehole for extraction.

[0008] In step (3), the flower tubes are connected in sequence by inserting the outer convex pipe joint of one flower tube into the inner concave pipe joint of another flower tube, and the rubber sealing ring realizes the sealing between the inner circle of the outer convex pipe joint and the outer circle of the inner concave pipe joint; the barbed convex ring on the inner circle of the inner concave pipe joint is inserted into the oblique groove on the outer circle of the outer convex pipe joint, so that the outer convex pipe joint and the inner concave pipe joint are axially connected as a whole; at least two inner concave pipe joints in the outer end of the orifice section flower tube are connected to the inside of the elbow pipe joint.

[0009] The specific process of step (4) is as follows: the main extraction route mainly extracts gas from the inside of the borehole through the extraction pipe, and at the same time, segmented gas extraction is carried out on each section of the borehole through the extraction branch route, the bend pipe, multiple pressure-boosting pipes and the gas flow holes; even if the middle section of the extraction borehole collapses and the coal body blocks the pipe, the extraction branch route can still extract gas from the bottom section of the hole through the pressure-boosting pipe extending to the bottom section of the hole.

[0010] Step (1) is specifically as follows: when the coal rock strength coefficient is 0<f≤0.3, the number of sections of the extraction borehole is 3≤n≤6; when the coal rock strength coefficient is 0.3<f≤0.5, the number of sections of the extraction borehole is 2≤n≤5; when the coal rock strength coefficient is 0.5<f≤0.8, the number of sections of the extraction borehole is 2≤n≤4.

[0011] By adopting the above technical scheme, the present invention has outstanding substantial characteristics and significant progress compared with the prior art. Specifically, the present invention is mainly used in the field of gas extraction technology. After the extraction drilling construction is completed, a flower pipe is installed. The pressure-compensating pipe provided in the flower pipe is connected to the extraction branch, and the extraction branch is connected to the extraction main pipe. In this way, the pressure can be compensated to each section in the borehole in real time through the pressure-compensating pipe, thereby solving the problems of negative pressure attenuation and reduction of effective extraction length caused by deformation and collapse of the borehole. At the same time, the flower pipe supports the hole wall, and the convex pipe joints and the concave pipe joints at both ends of the flower pipe are sealed and connected by rubber sealing rings, thereby improving the sealing of the flower pipe; the barbed convex ring on the inner circle of the concave pipe joint is inserted into the oblique groove on the outer circle of the convex pipe joint, thereby reducing the probability of adjacent flower pipes falling off.

[0012] To sum up, the present invention has a scientific principle and a simple structure. Through the design of the pressure-compensating tube on the inner wall of the flower tube body, the problem of negative pressure attenuation in the hole caused by borehole deformation or hole collapse can be effectively solved. In the case of borehole collapse, a reasonable extraction negative pressure is ensured in the hole, the effective extraction length is increased, thereby effectively improving the gas extraction efficiency and promoting safe and efficient mining in coal mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the deformation and collapse of the drilling hole after the drilling hole is sealed in the prior art; Figure 2 It is a schematic diagram of the overall structure of the segmented pressure-filled flower tube of the present invention; Figure 3 yes Figure 2 Cross-section of the flower tube at the bottom of the hole; Figure 4 yes Figure 2 Cross-section of the middle section of the flower tube; Figure 5 yes Figure 2 Cross-section of the flower tube at the orifice section; Figure 6 It is a schematic diagram of the structure of the flower tube at the bottom of the hole; Figure 7 It is a schematic diagram of the structure of the middle section of the flower tube; Figure 8 It is a structural schematic diagram of the orifice section flower tube; Fig. 9 yes Figure 8 Enlarged view of the middle and outer convex pipe joint; Fig.10 yes Figure 8 Enlarged view of the middle female pipe joint; Fig.11 yes Figure 2 An axial cross-sectional view of the connection between the middle elbow, the extraction pipe and the orifice section flower pipe; Fig.12 It is a schematic diagram of the plug-in assembly of an outer convex pipe joint and an inner concave pipe joint. DETAILED DESCRIPTION

[0014] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0015] like Figure 2-12 As shown, the segmented pressure-boosting flower tube for gas extraction from soft coal seams of the present invention comprises a flower tube body 1. The outer circle of the flower tube body 1 is provided with a plurality of gas flow holes 2 which are transparent inside and outside. A pressure-boosting pipe 3 is axially arranged on the inner wall of the flower tube body 1. The pressure-boosting pipe 3 is extruded integrally with the flower tube body 1. The front end of the pressure-boosting pipe 3 is integrally provided with an external convex pipe joint 4 extending out from the front port of the flower tube body 1. The rear end of the pressure-boosting pipe 3 is integrally provided with an internal concave pipe joint 5 which is matched with the external convex pipe joint 4. The rear end of the internal concave pipe joint 5 is flush with the rear end of the flower tube body 1.

[0016] The outer circle interference sleeve of the external convex pipe joint 4 is provided with a rubber sealing ring 7.

[0017] The outer circle of the convex pipe joint 4 is provided with an overall annular oblique groove 8, the opening of the oblique groove 8 faces the end of the flower tube body 1, and the inner circle of the concave pipe joint 5 is provided with a barbed convex ring 9 that is integrally matched with the oblique groove 8.

[0018] The method for using the segmented pressure-replenishing flower pipe for gas extraction in soft coal seams is to use the segmented pressure-replenishing flower pipe for gas extraction in soft coal seams for operation, including the following steps: (1) The number of sections of the extraction borehole is determined as n according to the coal rock solidity coefficient f at the construction site; (2) The area near the borehole opening and the bottom of the entire extraction borehole 10 is divided into a bottom section 11 and a borehole opening section 12, respectively. The bottom section 11 is a flower tube without an internal pressure-compensating tube 3 (e.g. Figure 2 , Figure 3 and Figure 6 As shown in the figure, the inner concave pipe joints 5 and / or the outer convex pipe joints 4 at both ends of the flower tube without the booster pipe 3 are retained; the principle of flower tube series connection is: the number of booster pipes 3 in the flower tubes used from the bottom section 11 to the orifice section 12 is increased one by one. Taking the number of sections n=3 of the extraction borehole 10 as an example, including the orifice section 12, the middle section 17 and the bottom section 11, as shown in the figure, Figure 2 , Figure 4 and Figure 7 As shown, the number of the pressure-compensating pipes in the middle section of the flower tube is 1; Figure 2 , Figure 5 and Figure 8 As shown, the number of the compensating pipes of the orifice section 12 flower pipe is 2.

[0019] (3) According to the number n of sections of the extraction borehole 10, different numbers of flower tubes of the booster tube 3 are connected in sequence, the flower tube of the borehole section 12 passes through the extraction tube 13 to connect to the elbow joint 14, the elbow joint 14 passes through the extraction tube 13 and is connected to the extraction main road 16 through the extraction branch road 15, and the outer port of the extraction tube 13 is connected to the extraction main road 16; (4) The gas inside the extraction borehole 10 is extracted, and the extraction branch 15 performs pressure-compensating extraction on each section inside the extraction borehole 10 through the pressure-compensating pipe 3.

[0020] In step (3), the flower tubes are connected in sequence by inserting the outer convex pipe joint 4 of one flower tube into the inner concave pipe joint 5 of another flower tube, and the rubber sealing ring 7 realizes the sealing between the inner circle of the outer convex pipe joint 4 and the outer circle of the concave pipe joint 5; the barbed convex ring 9 on the inner circle of the concave pipe joint 5 is inserted into the oblique groove 8 on the outer circle of the outer convex pipe joint 4, so that the outer convex pipe joint 4 and the concave pipe joint 5 are axially connected as a whole; at least two concave pipe joints 5 in the outer end of the flower tube of the orifice section 12 are connected to the inside of the elbow pipe joint 14.

[0021] The specific process of step (4) is as follows: the main extraction route 16 mainly extracts gas from the inside of the borehole through the extraction pipe 13, and at the same time, segmented gas extraction is performed on each section inside the borehole through the extraction branch route 15, the bent pipe, multiple pressure-boosting pipes 3 and the gas flow hole 2; even if the middle section 17 of the extraction borehole 10 collapses and the coal body blocks the flower pipe, the extraction branch route 15 can still extract gas from the bottom section 11 of the hole through the pressure-boosting pipe 3 extending to the bottom section 11 of the hole.

[0022] Step (1) is as follows: when the coal rock strength coefficient is 0<f≤0.3, the number of sections of the extraction borehole 10 is 3≤n≤6; when the coal rock strength coefficient is 0.3<f≤0.5, the number of sections of the extraction borehole 10 is 2≤n≤5; when the coal rock strength coefficient is 0.5<f≤0.8, the number of sections of the extraction borehole 10 is 2≤n≤4. For example, if the number of sections of the extraction borehole 10 is 4, the number of the compensating pipes 3 inside the flower pipe body 1 is 0, 1, 2, and 3 from the bottom of the hole to the hole mouth.

[0023] The above embodiments illustrate the basic principles and features of the present invention, but the above only illustrates the preferred embodiments of the present invention and is not limited to the embodiments. Under the inspiration of this patent, a person skilled in the art can make many forms of deformation and improvement without departing from the scope of protection of the present invention and the claims, which are all within the protection scope of the present invention. Therefore, the patent and protection scope of the present invention shall be subject to the attached claims.

Claims

1. A segmented pressure-replenishing flower pipe for gas extraction in soft coal seams, comprising a flower pipe body, a plurality of gas flow holes which are transparent inside and outside are opened on the outer circle of the flower pipe body, and the characteristics are: A pressure-compensating tube is axially arranged on the inner wall of the flower tube body. The pressure-compensating tube and the flower tube body are extruded as one piece. The front end of the pressure-compensating tube is integrally provided with an external convex pipe joint extending out of the front port of the flower tube body. The rear end of the pressure-compensating tube is integrally provided with an internal concave pipe joint matched with the external convex pipe joint. The rear end of the internal concave pipe joint is flush with the rear end of the flower tube body.

2. The segmented pressure-filled flower pipe for gas extraction in soft coal seams according to claim 1 is characterized in that: The outer circle interference sleeve of the external convex pipe joint is provided with a rubber sealing ring.

3. The segmented pressure-filled flower pipe for gas extraction in soft coal seams according to claim 2 is characterized in that: The outer circle of the convex pipe joint is provided with an overall annular oblique groove, the opening of the oblique groove faces the port of the flower tube body, and the inner circle of the concave pipe joint is provided with a barbed convex ring that is integrally matched with the oblique groove.

4. A method for using a segmented pressure-replenishing flower pipe for gas extraction from a soft coal seam, using the segmented pressure-replenishing flower pipe for gas extraction from a soft coal seam as claimed in claim 3, characterized in that: The following steps are involved: (1) The number of sections of the extraction borehole is determined as n according to the coal rock solidity coefficient f at the construction site; (2) The area near the hole mouth and the hole bottom of the entire extraction borehole is divided into the hole bottom section and the hole mouth section respectively. The hole bottom section adopts a flower tube without an internal pressure-boosting tube, and the inner concave pipe joints and / or outer convex pipe joints at both ends of the flower tube without a pressure-boosting tube are retained; the principle of connecting the flower tubes in series is: the number of pressure-boosting tubes in the flower tubes used from the hole bottom section to the hole mouth section increases by one successively; (3) According to the number of segments n of the extraction borehole, different numbers of flower tubes of the booster pipe are connected in sequence. The flower tube of the borehole mouth section passes through the extraction pipe and is connected to the elbow joint. The elbow joint passes through the extraction pipe and is connected to the extraction main road through the extraction branch road. The outer port of the extraction pipe is connected to the extraction main road. (4) The gas inside the extraction borehole is extracted, and the extraction branch uses the pressure-boosting pipe to supplement the pressure in each section of the extraction borehole for extraction.

5. The method for using the segmented pressure-filled flower pipe for gas extraction in soft coal seams according to claim 4 is characterized in that: In step (3), the flower tubes are connected in sequence by inserting the outer convex pipe joint of one flower tube into the inner concave pipe joint of another flower tube, and the rubber sealing ring realizes the sealing between the inner circle of the outer convex pipe joint and the outer circle of the inner concave pipe joint; the barbed convex ring on the inner circle of the inner concave pipe joint is inserted into the oblique groove on the outer circle of the outer convex pipe joint, so that the outer convex pipe joint and the inner concave pipe joint are axially connected as a whole; at least two inner concave pipe joints in the outer end of the orifice section flower tube are connected to the inside of the elbow pipe joint.

6. The method for using the segmented pressure-filled flower pipe for gas extraction in soft coal seams according to claim 4 is characterized in that: The specific process of step (4) is as follows: the main extraction route mainly extracts gas from the inside of the borehole through the extraction pipe, and at the same time, segmented gas extraction is carried out on each section of the borehole through the extraction branch route, the bend pipe, multiple pressure-boosting pipes and the gas flow holes; even if the middle section of the extraction borehole collapses and the coal body blocks the pipe, the extraction branch route can still extract gas from the bottom section of the hole through the pressure-boosting pipe extending to the bottom section of the hole.

7. The method for using the segmented pressure-filled flower pipe for gas extraction in soft coal seams according to claim 4 is characterized in that: Step (1) is specifically as follows: when the coal rock strength coefficient is 0<f≤0.3, the number of sections of the extraction borehole is 3≤n≤6; when the coal rock strength coefficient is 0.3<f≤0.5, the number of sections of the extraction borehole is 2≤n≤5; when the coal rock strength coefficient is 0.5<f≤0.8, the number of sections of the extraction borehole is 2≤n≤4.

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