Horizontal well jet axial slotted pressure relief coal and coalbed methane co-mining method
By pre-setting slots on the casing and using the lateral nozzles of the directional structure-guided water jet tool string to make axial cuts, the problem of low coalbed methane permeability was solved, achieving efficient co-extraction of coal and coalbed methane, and improving resource utilization and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHONGQING UNIV
- Filing Date
- 2025-01-18
- Publication Date
- 2026-06-23
AI Technical Summary
my country's coal mines generally have high coalbed methane resources but low permeability, making extraction difficult. Existing technologies are unable to achieve efficient and coordinated development of coal and coalbed methane, resulting in the direct discharge of coalbed methane resources into the air and low resource utilization.
The horizontal well jet axial slotting technology is adopted. By pre-setting slots on the casing, the lateral nozzles of the water jet tool string with a directional structure are used to make continuous axial slots, forming an effective fracture network, which improves coal seam permeability and mining efficiency.
It improves the extraction efficiency of coalbed methane and the mining efficiency of coal, increases the recovery rate and resource utilization rate of coalbed methane, reduces mining risks, and realizes safe and efficient co-mining of coal and coalbed methane.
Smart Images
Figure CN119860194B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coalbed methane extraction, specifically a method for co-extracting coal and coalbed methane using horizontal well jet axial slotting depressurization. Background Technology
[0002] In recent years, with the increasing awareness of the importance of developing coalbed methane resources and strengthening coal mine gas disaster management, as well as their interrelationship, people's concepts have evolved from "gas extraction first, coal extraction later" to the concept of "coordinated development of coal and coalbed methane resources." Extensive research has been conducted on different geological conditions, providing important guidance for the coordinated development of coal and coalbed methane in coal mining areas. In my country, coalbed methane content in mines is generally high, with low permeability. Coalfield geological structures are diverse, making extraction difficult. As mining depth increases, the occurrence pressure and geostress increase, further increasing the difficulty of extraction. Coal and coalbed methane are typical symbiotic minerals of the same origin; coal mining and coalbed methane development both promote and constrain each other. Historically, coal mines have extracted coalbed methane primarily for safety, resulting in the direct discharge of large amounts of coalbed methane resources. However, coordinated development of coal and coalbed methane improves resource recovery and utilization rates.
[0003] Based on the coal mining conditions in my country, three coordinated development models under typical geological conditions have been initially proposed: the Jincheng model under high permeability and medium-hard coal seam conditions, the Lianghuai model under low permeability and outburst soft coal seam conditions, and the Songzao model under complex geological conditions.
[0004] Coordinated development of coal and coalbed methane involves developing a comprehensive development and utilization plan for coal and coalbed methane resources in a target area. This plan takes into account factors such as development timeline, spatial layout, and mining and extraction deployment. It ensures unified coordination, makes full use of well, roadway, and borehole engineering, selects reasonable development methods, and fully leverages the mutually beneficial effects of gas extraction and coal mining. The goal is to maximize the development of coalbed methane while conducting coal mining under safe conditions, thereby achieving safe and efficient development of coal and coalbed methane resources and realizing the most ideal comprehensive benefits.
[0005] However, due to the diverse coal-bearing strata and coalbed methane reservoir types in my country, and the highly complex geological environments in which coalbed methane is found, the technological approaches for its development vary considerably. Therefore, exploring and researching methods suitable for the co-extraction of coal resources and coalbed methane under various conditions is extremely crucial and important. Summary of the Invention
[0006] This invention provides a method for co-extracting coal and coalbed methane using horizontal well jet axial slotting for pressure relief. It adopts a surface development model and is based on hydraulic slotting technology to perform continuous axial slotting. After the slotting is completed, coalbed methane is extracted and coal is mined, which can achieve a higher degree of coal seam pressure relief and mining efficiency.
[0007] The technical solution of this invention is as follows:
[0008] A method for co-extracting coal and coalbed methane using horizontal well jet axial slotting decompression includes: horizontal well construction, axial continuous hydraulic slotting, coal seam drainage and decompression, and co-extracting coal and coalbed methane.
[0009] When constructing a horizontal well, a horizontal well is formed by drilling in the coal seam along the direction of minimum principal stress.
[0010] The steps of axial continuous hydraulic cutting include:
[0011] The casing is lowered into the horizontal well; the casing has multiple slots along its axial direction, and the casing has a directional structure along its axial direction inside;
[0012] The water jet tool string is lowered into the casing, and the lateral nozzle of the water jet tool string is kept to move in a directional manner along the directional structure; the water jet tool string includes an oil pipe for conveying high-pressure water, a water jet injector provided at the end of the oil pipe, a directional eccentric and a second centralizer mounted on the oil pipe, and the water jet injector includes a lateral nozzle and an axial nozzle.
[0013] When the lateral nozzle moves along the directional structure to align with the foremost slot on the casing, the high-pressure water ejected by the lateral nozzle passes through the foremost slot and impacts the coal seam, and the high-pressure water ejected by the axial nozzle pushes the tubing backward in the horizontal direction.
[0014] After each coal seam cut at a slot is completed, water injection is stopped, and the oil pipe is pulled back a predetermined distance. When the lateral nozzle moves backward along the directional structure and aligns with the next slot on the casing, the high-pressure water sprayed by the lateral nozzle passes through the next slot and impacts the coal seam, while the high-pressure water sprayed by the axial nozzle continues to push the oil pipe backward in the horizontal direction. This cycle is repeated until the coal seam cut at the last slot is completed.
[0015] Furthermore, the orientation structure includes: a continuous slide rail disposed within the sleeve along its axial direction;
[0016] When cutting seams in a coal seam, the nozzle of the lateral nozzle is embedded in the continuous slide rail, and the nozzle of the lateral nozzle is positioned opposite to the corresponding slot.
[0017] Furthermore, the orientation structure includes: a plurality of sliding grooves and a plurality of segmented sliding rails disposed within the sleeve along its axial direction;
[0018] The segmented slide rails are provided at positions opposite to the openings of each slot. The slide grooves are provided on the remaining axial pipe walls of the sleeve, excluding each slot. The ends of the segmented slide rails are configured as funnel-shaped inlets, which are opposite to the ends of adjacent segmented slide rails.
[0019] Furthermore, the tail end of the segmented slide rail is provided with an anti-accidental opening device to block the lateral nozzle;
[0020] When the backward pulling force of the lateral nozzle exceeds the maximum support force provided by the anti-accidental opening device, the anti-accidental opening device releases the restriction on the lateral nozzle.
[0021] Furthermore, the continuous slide rail includes a first slide plate and a second slide plate opposite to each other, and both the first slide plate and the second slide plate include: a connecting plate and a support plate rotatably connected by a rotating member, the connecting plate being connected to the sleeve; the nozzle of the lateral nozzle is embedded between the two support plates;
[0022] When the weight of the coal seam fragments accumulated on the support plate exceeds the maximum supporting force provided by the rotating component, the support plate rotates relative to the connecting plate, causing the coal seam fragments to slide into the annulus between the tubing and the casing.
[0023] Furthermore, the surface of the segmented slide rail is treated with a polyurethane coating.
[0024] The beneficial effects of this invention are as follows:
[0025] Because many slots are pre-cut on the casing, the high-pressure water sprayed from the side nozzles does not need to be sprayed downhole onto the casing. This reduces the pressure of the high-pressure water impacting the coal seam, lowers the difficulty of cutting slots with the side nozzles, and improves cutting efficiency.
[0026] Because the angle of the casing is uncontrollable when it is run into a horizontal well, this uncontrollability can cause the lateral nozzles on the water jet tool string to be unable to target the slot after it is run into the casing, thus preventing slotting operations. In this embodiment, relying on the directional structure installed inside the casing, the lateral nozzles of the water jet tool string are assembled with the directional structure before the water jet tool string is run into the casing. The directional structure limits the angle of the lateral nozzles of the water jet tool string, ensuring that the lateral nozzles remain aligned with the slot, thus guaranteeing accurate slotting operations. Furthermore, by limiting the angle of the lateral nozzles of the water jet tool string through the directional structure, the lateral nozzles will not deflect due to the deflection of the water jet tool string when it retracts. Attached Figure Description
[0027] Figure 1This is a schematic diagram illustrating the horizontal well construction process in an embodiment of this application;
[0028] Figure 2 This is a schematic diagram of axial continuous hydraulic cutting in an embodiment of this application;
[0029] Figure 3 for Figure 2 A magnified view of a portion of the image;
[0030] Figure 4 for Figure 3 AA section view;
[0031] Figure 5 This is a flowchart illustrating the method in an embodiment of this application;
[0032] Figure 6 This is a schematic diagram of the slide rail in an embodiment of this application;
[0033] Figure 7 This is a schematic diagram of the anti-accidental opening device installed in the slide rail in an embodiment of this application;
[0034] Figure 8 This is a schematic diagram of the rotating component in an embodiment of this application. Detailed Implementation
[0035] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. The embodiments described below do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. The flowcharts shown in the drawings are merely illustrative and do not necessarily include all contents and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps may be decomposed, while others may be combined or partially combined; therefore, the actual order of execution may change depending on the actual situation.
[0036] Reference Figures 1-5 This application provides a method for co-extracting coal and coalbed methane using horizontal well jet axial slotting depressurization, including: horizontal well construction, axial continuous hydraulic slotting, coal seam drainage depressurization, and co-extracting coal and coalbed methane.
[0037] like Figure 1 When constructing a horizontal well, drilling equipment is used to drill directionally along the direction of minimum principal stress, thereby forming a horizontal well in coal seam 2. The drilling equipment includes a derrick 11, a drilling string connecting the derrick 11, a wellhead device 13, and a surface device 14. The drilling string includes a drill pipe 121, a first centralizer 122 installed between the vertical and horizontal wells, and a drill bit 123 installed at the end of the drill pipe 121.
[0038] See attached document Figures 2-4 When performing axial continuous hydraulic cutting, follow these steps:
[0039] The casing 3 is lowered into the horizontal well; the casing 3 is provided with a plurality of grooves 31 along its axial direction, and the casing 3 is provided with an directional structure along its axial direction inside its axial direction.
[0040] The water jet tool string is lowered into the casing 3, and the lateral nozzle of the water jet tool string is kept to move in a directional manner along the directional structure; the water jet tool string includes an oil pipe 41 for conveying high-pressure water, a water jet injector provided at the end of the oil pipe 41, a directional eccentric 43 and a second centralizer 42 mounted on the oil pipe 41, and the water jet injector includes a lateral nozzle 44 and an axial nozzle 45;
[0041] When the lateral nozzle 44 moves along the directional structure to align with the foremost slot on the casing 3, the high-pressure water ejected by the lateral nozzle 44 passes through the foremost slot and impacts the coal seam 2, and the high-pressure water ejected by the axial nozzle 45 pushes the oil pipe 41 backward in the horizontal direction.
[0042] After each coal seam cut at a slot is completed, water injection is stopped, and the oil pipe 41 is pulled back a predetermined distance. When the lateral nozzle 44 moves backward along the directional structure and aligns with the next slot on the casing 3, the high-pressure water sprayed by the lateral nozzle 44 passes through the next slot and impacts the coal seam 2, while the high-pressure water sprayed by the axial nozzle 45 continues to push the water jet tool string backward in the horizontal direction. This cycle is repeated until the coal seam cut at the last slot is completed.
[0043] When constructing a horizontal well, drilling along the direction of the minimum principal stress occurs in areas with weak rock mechanics. Drilling along this direction makes it easier to form extended fractures in coal seam 2, increasing coal seam permeability, improving coalbed methane conductivity, and facilitating coalbed methane desorption, thus increasing recovery rate. The fracture network formed by drilling along the direction of the minimum principal stress can better connect with natural fractures in the coal seam, forming more efficient seepage channels. Compared to other directions, the flow resistance of fluids in these fractures is lower, which is beneficial for coalbed methane desorption from the coal matrix and rapid flow into the wellbore. It also facilitates the removal of water from the coal body, reducing the water-locking effect and thus improving coal mining efficiency. The minimum principal stress is the smallest of the three principal stresses, and the stress perpendicular to the fracture direction is relatively small, resulting in a weaker force acting on the fracture surface to close it. Unclosed fractures can also increase the permeability of the coal body, allowing more coal to exchange gases with the outside environment, which is beneficial for extracting combustible gases from the coal, thereby increasing coal production.
[0044] Combination Figure 5After drilling is completed, a casing 3 of a certain size is lowered. When the target formation (below 1500m) is reached, the lowering of the casing 3 is stopped. Cement slurry 5 is injected into the casing 3 to fix the casing 3 to the well wall, prevent well wall collapse, and control the wellhead pressure.
[0045] In this embodiment, the sleeve 3 is pre-cut with multiple slots 31 of a specific length using axial continuous hydraulic cutting technology. The gap between the multiple slots 31 is set between 0.5m and 1m, for example, 0.5m, 0.7m, 1m, etc.; and these slots 31 form a slot mesh on the sleeve 3 in the radial direction.
[0046] In the above method of this application, since many slots 31 are pre-cut on the casing 3, the high-pressure water sprayed by the side nozzle 44 does not need to be sprayed downhole onto the casing 3, which can reduce the pressure when the high-pressure water impacts the coal seam 2, reduce the difficulty of cutting slots by the side nozzle 44, and improve the cutting efficiency.
[0047] Because the angle of the casing 3 downhole is uncontrollable when it is lowered into the horizontal well, this uncontrollability can cause the lateral nozzle 44 on the water jet tool string to fail to align with the slot 31 after the string is lowered into the casing 3, thus preventing the slotting operation from being performed. In this embodiment, relying on the directional structure installed inside the casing 3, the lateral nozzle 44 of the water jet tool string is assembled with the directional structure before it is lowered into the casing 3. The directional structure limits the angle of the lateral nozzle 44, ensuring that the lateral nozzle 44 remains aligned with the slot 31, thus guaranteeing the accurate execution of the slotting operation. Furthermore, by limiting the angle of the lateral nozzle 44 through the directional structure, the lateral nozzle 44 will not deflect due to the deflection of the water jet tool string when it retracts.
[0048] Reference Figure 5After casing 3 is fixed, tubing head 6 and self-sealing wellhead are installed at the wellhead, tubing 41 is run in, and the self-sealing wellhead device is assembled. During the lowering of tubing 41, the threads must be tightened in the correct direction to meet the torque requirements. The lowering speed of tubing 41 should be controlled at ≤0.03m / s, and when tubing 41 reaches slot 31, the speed should be further reduced to ≤0.02m / s. After tubing 41 reaches the horizontal section of casing 3, the second stabilizer 42 and directional eccentricity 43 ensure that tubing 41 can move in the horizontal direction. The movement of tubing is stopped when the lateral nozzle 44 reaches the farthest point between the directional structure and casing. When high-pressure water jetting is injected, the directional eccentricity 43 and the second stabilizer 42, through gravity and torque, play a role in preventing deviation and vibration of tubing 41, while stabilizing the drilling direction, preventing well inclination changes, and reducing the resistance when tubing 41 is dragged.
[0049] Combination Figure 5 After drilling and tubing installation in a multi-branch horizontal well, axial continuous hydraulic slotting technology provides high-pressure water via the work vehicle 7, which is injected into the tubing 41 through the continuous tubing 8. The high-pressure water is ejected through the axial nozzle 45, generating a reverse thrust to ensure the tubing 41 remains horizontal. The high-pressure water jet ejected from the lateral nozzle 44 impacts the coal seam 2 through the slot 31, forming a spindle-shaped cavity. After the first slot is formed, the tubing 41 retracts. When the second slot is formed, the coal between the maximum width horizontal line and the casing 3 wall breaks and collapses due to gravity and the impact of the high-pressure water. Impacting and breaking the coal between the maximum width horizontal line and the highest horizontal line of the cavity further regularizes the shape of the entire cavity.
[0050] Reference Figure 6 In one embodiment of this application, the directional structure includes a continuous slide rail 32 arranged axially within the casing 3; during coal seam cutting, the nozzle of the lateral nozzle 44 is embedded in the continuous slide rail 32, and the nozzle of the lateral nozzle 44 is positioned opposite to the corresponding slot 31. This continuous slide rail arrangement ensures continuous orientation of the lateral nozzle 44 without requiring additional structural design within the casing.
[0051] In another embodiment of this application, the directional structure includes: a plurality of grooves and a plurality of segmented slide rails 34 arranged axially within the sleeve 3; each segmented slide rail 34 is provided at a position opposite to the opening of each groove 31; the grooves are provided on the remaining axial wall of the sleeve 3 excluding each groove 31; and the ends of each segmented slide rail 34 are configured as flared inlets, the inlets being opposite to the ends of adjacent segmented slide rails 34. The arrangement of multiple segmented slide rails 34 reduces installation costs. When the lateral nozzle 44 enters the segmented slide rail 34 along the groove, the flared inlet provides an adjustment position, buffering the entry into the segmented slide rail 34.
[0052] In this embodiment, a polyurethane coating is applied to the surface of the segmented slide rail 34.
[0053] Combination Figure 6 For the continuous slide rail 32 and the segmented slide rail 34 mentioned above, each includes a first sliding plate and a second sliding plate. The first sliding plate and the second sliding plate each include a connecting plate and a support plate that are rotatably connected by a rotating member 321. The connecting plate is connected to the casing 3. The nozzle of the lateral nozzle 44 is embedded between the two support plates. When the weight of the coal seam fragments accumulated on the support plate exceeds the maximum support force provided by the rotating member 321, the support plate rotates relative to the connecting plate, causing the coal seam fragments to slide into the annulus 33 between the oil pipe 41 and the casing 3.
[0054] In this embodiment, the rotating member 321 can be configured as similar to Figure 8 The roller structure in the middle, namely the connecting plate and the support plate, achieves the rotation of the support plate by meshing with the roller structure; of course, the rotating part 321 can also be set as a structure similar to a torsion spring.
[0055] Reference Figure 7 The end of the segmented slide rail 34 is provided with an anti-accidental opening device 322 for blocking the lateral nozzle 44; when the backward pulling force of the lateral nozzle 44 exceeds the maximum support force provided by the anti-accidental opening device 322, the anti-accidental opening device 322 releases the restriction on the lateral nozzle 44.
[0056] Combination Figure 5 After the seam is cut, coal seam fragments and coalbed methane are discharged along with the effluent through the annulus 33 of the casing 3 and the tubing 41, and simultaneously reach the separation device 9 for processing. The coal body undergoes certain cracking, the coal seam voids increase, and the permeability of the coalbed methane is improved.
[0057] Combination Figure 5After all the branch wells have completed water jet cavity creation for coal and coalbed methane extraction, the water jet tool string is replaced with a production string. Using the production string, fluids from the cavity and main horizontal well are extracted to the surface under pressure differential. Simultaneously, as water is extracted into the water storage pit, coalbed methane is extracted to the gas gathering and transmission device under pressure differential. The production string includes tubing, a drain pump located at the end of the tubing, and a pressure gauge connected to the tubing and located on the surface. As water flows from the coal seam into the cavity and is discharged by the drain pump, the formation pressure decreases. When the formation pressure drops below the critical desorption pressure, coalbed methane begins to desorb and accumulates in the cavity. Under pressure, the coalbed methane is extracted along the annulus between the production string and the casing to the gas gathering and transmission device for collection and storage.
[0058] The horizontal well jet axial slotting depressurization coal and coalbed methane co-extraction method proposed in this embodiment can, to a certain extent, increase the coal seam depressurization area, improve coalbed methane overflow and coalbed methane extraction efficiency, reduce gas pressure during coal mining, reduce mining risks, and improve resource utilization.
[0059] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0060] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.
[0061] It should also be noted that, in this document, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, relational terms such as "first" and "second" are used to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements does not include those elements, but also includes other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.
[0062] The technical solution provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand this invention, and the content of this specification should not be construed as a limitation of this invention. Furthermore, for those skilled in the art, there will be different forms of changes in the specific implementation methods and application scope based on this invention. It is neither necessary nor possible to exhaustively list all implementation methods here, but obvious changes or modifications derived therefrom are still within the protection scope of this invention.
Claims
1. A method for co-producing coal and coalbed methane using horizontal well jet axial slotting depressurization, characterized in that, include: Horizontal well construction, axial continuous hydraulic slotting, coal seam drainage and depressurization, and co-extraction of coal and coalbed methane; When constructing a horizontal well, a horizontal well is formed by drilling in the coal seam along the direction of minimum principal stress. The steps of axial continuous hydraulic cutting include: The casing is lowered into the horizontal well; the casing has multiple slots along its axial direction, and the casing has a directional structure along its axial direction inside; The water jet tool string is lowered into the casing, and the lateral nozzle of the water jet tool string is kept to move in a directional manner along the directional structure; the water jet tool string includes an oil pipe for conveying high-pressure water, a water jet injector provided at the end of the oil pipe, a directional eccentric and a second centralizer mounted on the oil pipe, and the water jet injector includes a lateral nozzle and an axial nozzle. When the lateral nozzle moves along the directional structure to align with the foremost slot on the casing, the high-pressure water ejected by the lateral nozzle passes through the foremost slot and impacts the coal seam, and the high-pressure water ejected by the axial nozzle pushes the tubing backward in the horizontal direction. After each coal seam cut at a slot is completed, water injection is stopped, and the oil pipe is pulled back a predetermined distance. When the lateral nozzle moves backward along the directional structure and aligns with the next slot on the casing, the high-pressure water sprayed by the lateral nozzle passes through the next slot and impacts the coal seam, while the high-pressure water sprayed by the axial nozzle continues to push the oil pipe backward in the horizontal direction. This cycle is repeated until the coal seam cut at the last slot is completed.
2. The method for co-producing coal and coalbed methane using horizontal well jet axial slotting decompression as described in claim 1, characterized in that, The directional structure includes: a continuous slide rail disposed inside the sleeve along its axial direction; When cutting seams in a coal seam, the nozzle of the lateral nozzle is embedded in the continuous slide rail, and the nozzle of the lateral nozzle is positioned opposite to the corresponding slot.
3. The method for co-producing coal and coalbed methane using horizontal well jet axial slotting decompression as described in claim 1, characterized in that, The orientation structure includes: a plurality of sliding grooves and a plurality of segmented sliding rails arranged in the sleeve along its axial direction; The segmented slide rails are provided at positions opposite to the openings of each slot. The slide grooves are provided on the remaining axial pipe walls of the sleeve, excluding each slot. The ends of the segmented slide rails are configured as funnel-shaped inlets, which are opposite to the ends of adjacent segmented slide rails.
4. The method for co-producing coal and coalbed methane using horizontal well jet axial slotting decompression as described in claim 3, characterized in that, The end of the segmented slide rail is provided with an anti-accidental opening device to block the lateral nozzle. When the backward pulling force of the lateral nozzle exceeds the maximum support force provided by the anti-accidental opening device, the anti-accidental opening device releases the restriction on the lateral nozzle.
5. The method for co-producing coal and coalbed methane using horizontal well jet axial slotting decompression according to claim 2, characterized in that, The continuous slide rail includes a first slide plate and a second slide plate opposite to each other. The first slide plate and the second slide plate each include a connecting plate and a support plate that are rotatably connected by a rotating member. The connecting plate is connected to the sleeve. The nozzle of the lateral nozzle is embedded between the two support plates. When the weight of the coal seam fragments accumulated on the support plate exceeds the maximum supporting force provided by the rotating component, the support plate rotates relative to the connecting plate, causing the coal seam fragments to slide into the annulus between the tubing and the casing.
6. The method for co-producing coal and coalbed methane using horizontal well jet axial slotting decompression according to claim 3, characterized in that, The surface of the segmented slide rail is treated with a polyurethane coating.