A sliding multi-lane flower tube and method of use thereof

Abstract

The application discloses a sliding multi-channel flower pipe and a use method thereof, and belongs to the technical field of drilling hole protection, medium conveying and pumping and draining. In view of the problems of single channel, easy deformation under pressure and inconvenient assembly of the existing coal seam drilling flower pipe, the flower pipe comprises an open outer pipe and a coaxially nested closed inner pipe; the open outer pipe is provided with radial circular holes in the pipe wall, and the inner wall is provided with axial grooves; the closed inner pipe is provided with axial convex edges which are in sliding cooperation with the grooves, and independent central medium channels are formed in the pipe; the convex edges separate the annular gap between the inner pipe and the outer pipe into a plurality of mutually independent peripheral medium channels. The convex edges and the grooves simultaneously realize sliding guidance, circumferential limiting and radial force transmission, and the inner pipe and the outer pipe cooperatively bear to improve the overall anti-deformation capacity. The application can realize multi-channel independent pumping and draining and medium conveying, is fast to assemble, and can be used for underground drilling operations such as soft and broken coal seam drilling gas extraction.

Description

Technical Field

[0001] This invention relates to the field of borehole protection and in-hole media transportation technology, specifically to a sliding multi-channel perforated pipe and its usage method, which can be applied to underground drilling operations such as coal seam gas extraction, borehole drainage, and grouting reinforcement. Background Technology

[0002] After coal seam drilling is completed, the borehole is prone to problems such as borehole wall deformation, local diameter reduction, coal spalling, and coal slag accumulation due to factors such as low coal strength, ground stress disturbance, gas pressure, borehole pressure relief, and long-term borehole wall deformation. Especially in soft or broken coal seams, the stability of the borehole after drilling is poor, and it is necessary to promptly lower perforated pipes into the borehole to support the borehole wall and maintain the flow channel of the medium inside the borehole.

[0003] Existing perforated pipes typically employ a single-layer perforated pipe structure with multiple through-holes in the pipe wall. Media such as gas, water, and coal slag from the boreholes enter the perforated pipe through these through-holes and exit along a single channel inside the pipe. While this type of perforated pipe has a simple structure, it still suffers from the following problems: Firstly, existing single-layer perforated pipes typically only form one medium channel inside, making it difficult to simultaneously meet the needs of multiple operations such as gas extraction, compressed air transportation, liquid transportation, and borehole drainage. When performing multi-process operations, the pipe string needs to be repeatedly raised and lowered, resulting in low operational efficiency.

[0004] Secondly, the inlet or outlet positions of the existing perforated pipes are usually fixed, making it difficult to flexibly adjust the position of the medium according to the changes in the location of the gas-rich area, water accumulation area, blockage area or collapse area in the borehole, thus failing to achieve precise zoning operations.

[0005] Third, when ordinary perforated pipes are squeezed by the borehole wall, the perforated pipe wall is prone to local deformation and collapse due to insufficient structural strength, which leads to channel blockage and affects the continuity of operation.

[0006] Therefore, it is necessary to provide a sliding multi-channel perforated pipe that can quickly complete the assembly of inner and outer tubes, improve the overall load-bearing capacity of the perforated pipe, and adjust the position of the medium according to the needs of the operation inside the hole. Summary of the Invention

[0007] The purpose of this invention is to solve the problems of limited number of channels in existing perforated tubes, fixed media action positions, inconvenient assembly of inner and outer tubes, and easy deformation of perforated tubes under pressure, and to provide a sliding multi-channel perforated tube and its usage method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A sliding multi-channel perforated tube includes an open outer tube and a closed inner tube. The wall of the open outer tube has several radially penetrating circular holes, and the inner wall of the open outer tube has at least two grooves extending axially along the open outer tube. The closed inner tube is coaxially disposed inside the open outer tube. The wall of the closed inner tube does not have radially through holes communicating with the outside of the open outer tube. The interior of the closed inner tube forms a central medium channel extending axially. The outer wall of the closed inner tube has protrusions that are the same number as the grooves and correspond one-to-one in position. An annular gap is formed between the outer wall of the closed inner tube and the inner wall of the open outer tube. Each of the protrusions is inserted into a corresponding groove and slides axially with the groove. The protrusions divide the annular gap into at least two independent peripheral medium channels. The closed inner tube can slide axially relative to the open outer tube, and the circumferential positioning between the closed inner tube and the open outer tube is maintained by the cooperation of the protrusions and grooves.

[0009] Furthermore, the convex ridge extends radially outward along the closed inner tube, with the outer end of the convex ridge extending into the corresponding groove. The side of the convex ridge slides in contact with the groove sidewall, forming a guide fit structure that allows the closed inner tube to slide axially and restricts the circumferential rotation of the closed inner tube.

[0010] Furthermore, each of the protruding ribs is continuously connected along the axial direction of the closed inner tube, and each of the grooves is continuously connected along the axial direction of the open outer tube. The closed inner tube is installed inside the open outer tube by axial insertion of the protruding ribs and grooves.

[0011] Furthermore, each groove and protrusion is provided in three parts, with the three grooves spaced apart circumferentially along the open outer tube and the three protrusions spaced apart circumferentially along the closed inner tube.

[0012] Furthermore, the three grooves are evenly distributed along the circumference of the open outer tube, and the central angle between two adjacent grooves is 120°; the three convex ridges are evenly distributed along the circumference of the closed inner tube, and the central angle between two adjacent convex ridges is 120°.

[0013] Furthermore, the outer end face of the convex ridge slides in contact with the bottom surface of the corresponding groove, and the two side faces of the convex ridge slide in contact with the two side walls of the corresponding groove, respectively.

[0014] Furthermore, the radial holes are arrayed along the axial and circumferential directions of the open outer tube, and the distribution area of ​​the radial holes corresponds one-to-one with the circumferential position of the peripheral medium channel.

[0015] Furthermore, the end of the sealed inner tube near the borehole opening is provided with a connecting end for connecting to an external medium delivery pipeline or a pumping pipeline, and the end of the sealed inner tube near the bottom of the borehole is provided with an end opening that communicates with the central medium channel.

[0016] Furthermore, when the open outer tube is subjected to a radial load applied by the borehole wall, the open outer tube transfers at least part of the radial load to the closed inner tube through the contact between the groove and the ridge, so that the open outer tube and the closed inner tube share the external load.

[0017] This invention also provides a method for using the above-mentioned sliding multi-channel flower tube, including the following steps: S1. Align each of the protruding ridges on the outer wall of the closed inner tube with each of the grooves on the inner wall of the open outer tube in the circumferential direction. S2. Insert the closed inner tube into the open outer tube along the axial direction of the open outer tube, so that each protrusion enters the corresponding groove, and the flower tube assembly is completed. S3. The assembled sliding multi-channel perforated pipe is lowered from the borehole opening into the borehole to the target depth. It is then connected to external pipelines through the central medium channel and each peripheral medium channel to carry out medium pumping and transportation operations.

[0018] Using the above technical solution, the specific functions of the main components in this invention are as follows: 1) Open outer tube: As the outer support structure of the perforated tube, it directly contacts the borehole wall and bears the main support function of the borehole wall; the radial circular holes in the tube wall serve as channels for the medium inside the borehole to enter the perforated tube, realizing the communication between the medium inside the borehole and the interior of the perforated tube; the grooves on the inner wall cooperate with the protrusions of the closed inner tube, playing the roles of sliding guidance, circumferential limiting and force transmission. When the borehole wall squeezes the open outer tube to generate radial load, the groove wall can abut against the protrusions to transfer the radial load to the closed inner tube, realizing the coordinated force sharing of the inner and outer tubes.

[0019] 2) Enclosed inner tube: As the inner structure of the flower tube, it forms an independent central medium channel, which can independently transport or pump out a single medium without interfering with the outer channel; the convex ridges on the outer wall cooperate with the grooves of the open outer tube to achieve axial sliding guidance on the one hand, and divide the annular gap into multiple independent outer medium channels on the other hand, while bearing the radial force transmission function, receiving the radial load transmitted from the open outer tube, and improving the overall structural strength.

[0020] 3) Central medium channel: An independent and enclosed axial channel that can be used for directional delivery of compressed air, grouting fluid and other media, or for precise extraction of media in specific areas at the bottom of the hole. The position of the medium can be adjusted by sliding the inner tube.

[0021] 4) Peripheral medium channels: Multiple independent channels formed by the annular gaps separated by convex ridges correspond to the radial circular holes at different circumferential positions of the open outer pipe, which can realize the partitioned pumping and drainage of different circumferential areas, or undertake different functions such as drainage and slag discharge.

[0022] 5) The structure of the convex ridge and groove has three functions: First, it is an axial sliding guide to ensure that the inner tube slides in a straight line without deviation; second, it is a circumferential limit to prevent relative rotation between the inner and outer tubes and maintain the circumferential position of each channel; third, it is a radial force transmission. When the open outer tube is subjected to radial extrusion load of the hole wall, the groove wall of the groove squeezes the convex ridge, and the load is transmitted to the closed inner tube. The inner and outer tubes share the external load and improve the overall resistance to deformation.

[0023] In summary, the overall technical effects of this invention are as follows: (1) Multi-channel independent operation with high functional integration: The central medium channel is formed by the closed inner tube, and multiple peripheral medium channels are formed by the convex ridge separating the annular gap. Multiple operations such as gas extraction, drainage, compressed air transportation, and grouting can be carried out at the same time without repeatedly raising and lowering the pipe column, which greatly improves the drilling efficiency.

[0024] (2) Easy assembly and reliable circumferential positioning: The assembly method of axial insertion of the convex ridge and the groove can quickly complete the coaxial assembly of the inner and outer tubes. At the same time, the cooperation between the groove and the convex ridge can restrict the relative rotation of the inner and outer tubes in the circumferential direction, ensure the stability of the circumferential position of each channel, and avoid channel misalignment.

[0025] (3) Strong overall load-bearing capacity and good deformation resistance: When the open outer tube is subjected to radial compression from the borehole wall, the load can be transferred to the closed inner tube through the contact between the groove and the ridge, and the inner and outer tubes jointly bear the external load. The open outer tube with the hole no longer bears all the ground stress load alone, which significantly improves the compressive, bending and deformation resistance of the perforated tube and extends the service life of the perforated tube in complex drilling environments.

[0026] (4) Good zonal extraction effect: Multiple peripheral media channels correspond to radial holes in different circumferential areas, which can be used to extract media in different directions of the borehole, thereby improving the targeting and efficiency of media extraction. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the sliding multi-channel flower tube in Embodiment 1 of the present invention; Figure 2 for Figure 1 A schematic diagram of the radial cross-section structure; Figure 3 This is a schematic diagram of the overall structure of the open outer tube in Embodiment 1 of the present invention; Figure 4 for Figure 3 A schematic diagram of the radial cross-section structure; Figure 5 This is a schematic diagram of the overall structure of the closed inner tube in Embodiment 1 of the present invention; Figure 6 for Figure 5 A schematic diagram of the radial cross-section structure; Figure 7 This is a schematic diagram of the overall structure of the open outer tube in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of the overall structure of the closed inner tube in Embodiment 2 of the present invention.

[0028] The attached diagram is labeled as follows: 1-Open outer tube, 2-Closed inner tube, 3-Radial circular hole, 4-Groove, 5-Central medium channel, 6-Protruding ridge, 7-Outer medium channel. Detailed Implementation

[0029] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Example 1

[0030] like Figures 1-6 As shown, this embodiment provides a sliding multi-channel flower tube, including an open outer tube 1 and a closed inner tube 2, which are coaxially nested.

[0031] The open outer tube 1 is a circular tube with several radial circular holes 3 penetrating the tube wall. The radial circular holes 3 are evenly distributed in an array along the axial and circumferential directions of the open outer tube 1. The inner wall of the open outer tube 1 has three axially extending grooves 4, which are evenly distributed along the circumference of the open outer tube 1, and the central angle between two adjacent grooves 4 is 120°.

[0032] The closed inner tube 2 is coaxially disposed inside the open outer tube 1. The wall of the closed inner tube 2 is a closed structure without radial through holes, thus forming an independent, axially extending central medium channel 5 inside the closed inner tube 2. The outer wall of the closed inner tube 2 is provided with three axially extending convex ribs 6, which are evenly distributed along the circumference of the closed inner tube 2. The central angle between two adjacent convex ribs 6 is 120°, and the positions of the convex ribs 6 correspond one-to-one with the grooves 4.

[0033] After the inner tube 2 is assembled, an annular gap is formed between its outer wall and the inner wall of the outer tube 1. Three protruding ribs 6 are inserted into three corresponding grooves 4. The outer end face of the protruding rib 6 slides in contact with the bottom surface of the groove 4, and the two side faces of the protruding rib 6 slide in contact with the two side walls of the groove 4. Thus, the protruding ribs 6 divide the annular gap into three independent peripheral medium channels 7. Each peripheral medium channel 7 corresponds to a radial hole 3 in a circumferential region on the outer tube 1. The medium in the hole can enter a single peripheral medium channel 7 through the radial hole 3 in the corresponding region.

[0034] The cooperation between the protruding rib 6 and the groove 4 forms a guiding structure, allowing the closed inner tube 2 to slide freely axially relative to the open outer tube 1, while restricting the relative circumferential rotation between the two, maintaining the circumferential position stability of each channel. When the open outer tube 1 is subjected to a radial load applied by the borehole wall, the open outer tube 1 transfers part of the radial load to the closed inner tube 2 through the contact between the groove wall of the groove 4 and the protruding rib 6, so that the open outer tube 1 and the closed inner tube 2 share the external load, improving the defect of the open outer tube being easily deformed under pressure, and enhancing the deformation resistance of the overall structure.

[0035] The inner closed tube 2 is provided with a connecting end near the borehole opening for connecting to an external medium delivery pipeline or a pumping pipeline; the inner closed tube 2 is provided with an end opening near the bottom of the borehole, which is connected to the central medium channel 5, and the medium can enter and exit the central medium channel 5 through the end opening.

[0036] As a preferred embodiment, threaded connection structures can be provided at both ends of the open outer tube 1 for connecting and extending multiple sections of the tube; a sealing joint can be provided at the end of the closed inner tube 2 for connecting multiple sections of the closed inner tube to ensure the sealing of the central medium channel after connection. This connection structure is a conventional and well-known structure for pipe connection in the field and is not a necessary technical feature of the present invention.

[0037] The method of using the sliding multi-channel flower tube in this embodiment includes the following steps: S1. Before assembly, align the three protruding ridges 6 on the outer wall of the closed inner tube 2 with the three grooves 4 on the inner wall of the open outer tube 1 in a circumferential direction to ensure that their circumferential positions correspond. S2. Push the closed inner tube 2 into the open outer tube 1 from the end along the axial direction of the open outer tube 1, so that each protrusion 6 is embedded in the corresponding groove 4, and the assembly of a single section of the flower tube is completed. If it is necessary to extend the tube column, multiple sections of open outer tube 1 and closed inner tube 2 can be connected in sequence using a known tube connection structure. S3. The assembled perforated pipe column is slowly lowered from the borehole opening to the preset depth inside the borehole. It is then connected to the external pipeline through the central medium channel 5 and each peripheral medium channel 7 to carry out medium pumping and transportation operations. Example 2

[0038] like Figure 7 , Figure 8 As shown, the structure of this embodiment is basically the same as that of Embodiment 1, with the only difference being: In this embodiment, the inner wall of the open outer tube 1 is provided with two axially extending grooves 4, which are symmetrically distributed circumferentially; correspondingly, the outer wall of the closed inner tube 2 is provided with two axially extending convex ridges 6, which are symmetrically distributed circumferentially. After assembly, the two convex ridges 6 divide the annular gap into two independent peripheral medium channels 7.

[0039] After assembly, the protruding rib 6 and the groove 4 still maintain the function of sliding fit and circumferential limiting; when the open outer tube 1 bears the radial load of the hole wall, the groove wall of the groove 4 squeezes the protruding rib 6, which can also transfer part of the radial load to the closed inner tube 2, so that the inner and outer tubes can bear the load together.

[0040] This embodiment is suitable for operation scenarios with small borehole diameter and low requirements for the number of channels. It has a simpler structure and is easier to assemble, while retaining the important functions of sliding adjustment, dual-tube load-bearing, and independent operation of dual channels.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sliding multi-channel flower tube, characterized in that: Includes open outer pipes and closed inner pipes; The open outer tube has a plurality of radial circular holes penetrating the tube wall, and the inner wall of the open outer tube has at least two grooves extending along the axial direction of the open outer tube. The closed inner tube is coaxially disposed inside the open outer tube. The wall of the closed inner tube does not have radial through holes communicating with the outside of the open outer tube. The interior of the closed inner tube forms a central medium channel extending along the axial direction. The outer wall of the closed inner tube is provided with protruding ridges that are the same number as the grooves and whose positions correspond one-to-one. An annular gap is formed between the outer wall of the closed inner tube and the inner wall of the open outer tube. Each of the protruding ridges is inserted into the corresponding groove and slides along the axial direction with the groove. The protruding ridges divide the annular gap into at least two independent peripheral medium channels. The closed inner tube can slide axially relative to the open outer tube, and the circumferential positioning between the closed inner tube and the open outer tube is maintained by the cooperation of the convex ridge and the groove.

2. The sliding multi-channel perforated tube according to claim 1, characterized in that: The protruding rib extends radially outward along the inner tube of the enclosure, with the outer end of the rib extending into the corresponding groove. The side of the rib slides in contact with the sidewall of the groove, forming a guide fit structure that allows the inner tube of the enclosure to slide axially and restricts the inner tube of the enclosure to rotate circumferentially.

3. The sliding multi-channel perforated tube according to claim 1, characterized in that: Each of the aforementioned protruding ribs is continuously connected along the axial direction of the closed inner tube, and each of the aforementioned grooves is continuously connected along the axial direction of the open outer tube. The closed inner tube is installed inside the open outer tube by axial insertion of the protruding ribs and grooves.

4. The sliding multi-channel perforated tube according to claim 1, characterized in that: The grooves and protrusions are each set to three, with the three grooves spaced apart along the circumference of the open outer tube and the three protrusions spaced apart along the circumference of the closed inner tube.

5. The sliding multi-channel perforated tube according to claim 4, characterized in that: The three grooves are evenly distributed along the circumference of the open outer tube, and the central angle between two adjacent grooves is 120°; the three convex ridges are evenly distributed along the circumference of the closed inner tube, and the central angle between two adjacent convex ridges is 120°.

6. The sliding multi-channel perforated tube according to claim 1, characterized in that: The outer end face of the protruding ridge slides in contact with the bottom surface of the corresponding groove, and the two sides of the protruding ridge slide in contact with the two side walls of the corresponding groove.

7. The sliding multi-channel perforated tube according to claim 1, characterized in that: The radial holes are arranged in an array along the axial and circumferential directions of the open outer tube, and the distribution area of ​​the radial holes corresponds one-to-one with the circumferential position of the peripheral medium channel.

8. The sliding multi-channel perforated tube according to claim 1, characterized in that: The closed inner tube has a connection end near the borehole opening for connecting to an external medium delivery pipeline or a pumping pipeline, and an end opening near the bottom of the borehole for communicating with the central medium channel.

9. The sliding multi-channel flower tube according to claim 1, characterized in that: When the open outer tube is subjected to a radial load applied by the borehole wall, the open outer tube transfers at least part of the radial load to the closed inner tube through the contact between the groove and the ridge, so that the open outer tube and the closed inner tube share the external load.

10. A method of using a sliding multi-channel flower tube according to any one of claims 1-9, characterized in that: Includes the following steps: S1. Align each of the protruding ridges on the outer wall of the closed inner tube with each of the grooves on the inner wall of the open outer tube in the circumferential direction. S2. Insert the closed inner tube into the open outer tube along the axial direction of the open outer tube, so that each protrusion enters the corresponding groove, and the flower tube assembly is completed. S3. The assembled sliding multi-channel perforated pipe is lowered from the borehole opening into the borehole to the target depth. It is then connected to external pipelines through the central medium channel and each peripheral medium channel to carry out medium pumping and transportation operations.

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