Separate layer fracturing pipe column device for coal-bed gas well

Abstract

The invention relates to the technical field of coal-bed gas separate-layer fracturing, and provides a coal-bed gas well separate-layer fracturing tubular column device which comprises a plurality of separate-layer fracturing devices, each separate-layer fracturing device comprises a fracturing jet assembly and a fracturing assembly, each fracturing jet assembly comprises a jet shell provided with a jet opening, a positioning ring and linkage teeth are arranged in each jet shell, and an impact column is arranged on each jet shell; the bidirectional driving assembly comprises an opposite rack meshed with the linkage teeth, the two ends of the opposite rack are connected with extrusion discs respectively, the surfaces of the extrusion discs are fixedly connected with touch pipes, and the outer sides of the touch pipes are sleeved with reset springs; the ball limiting ring is arranged on the extrusion disc; the two ends of the transition pipe are connected with the injection shell and the guide shell correspondingly, and the touch pipe extends to the guide shell; the layered sealing mechanism comprises filling teeth arranged in a sliding mode and a torsion disc capable of moving in the axial direction, and the torsion disc is connected with a rotatable rotating cylinder. Automatic fracturing can be completed by filling the blocking ball and continuously injecting the fracturing fluid, and the problem that complex operation and construction are needed in the fracturing process is solved.

Description

Technical Field

[0001] The present application relates to the technical field of coalbed methane layered fracturing, and in particular to a coalbed methane well layered fracturing string device. Background Art

[0002] The efficient development of coalbed methane (CBM) is not only an inevitable trend in the development and utilization of new energy sources, but also an objective requirement for atmospheric environmental protection, safe coal mining, easing energy supply and demand, and improving the energy supply structure. Due to the extremely low porosity and permeability of coal rock, CBM development is relatively difficult, requiring hydraulic fracturing to achieve efficient development. Fracturing is a key technology for increasing the productivity of CBM wells and is typically used in single-layer coal seam mining.

[0003] In the related art, the fracturing string device requires more complicated operation when in use, so that the splitter and the sandblaster act alternately to fix the string and perform sandblasting. This construction method requires strict compliance with the operation requirements to advance the construction one by one. Not only is the operation complicated, but it also requires a long operation cycle for layered fracturing. Moreover, the separators at both ends of the same layer need to be triggered one by one, which can easily cause triggering errors and fail to close the space. Summary of the Invention

[0004] In order to solve at least one of the above technical problems, the present application proposes a coalbed methane well layered fracturing string device.

[0005] In view of this, the present application proposes a layered fracturing string device for a coalbed methane well, comprising: a plurality of layered fracturing devices connected in sequence along the axial direction of the wellbore, the layered fracturing device comprising: a fracturing injection assembly, comprising an injection shell provided with an injection port, a positioning ring and a linkage tooth provided inside the injection shell, and an impact column provided on the injection shell; a two-way drive assembly, comprising opposing racks meshing with the linkage teeth, the opposing racks slidingly cooperating with the positioning rings, the two ends of the opposing racks being respectively connected to an extrusion disk, a touch tube being fixedly connected to the surface of the extrusion disk, and a return spring being sleeved on the outer side of the touch tube , the return spring is located in the injection shell; the ball limit ring is arranged on the extrusion disk, which is used to limit the stopping position of the inserted blocking ball to achieve layer isolation; the transition pipe is arranged at both ends of the injection shell, and the two ends of the transition pipe are respectively connected to the injection shell and the guide shell, and the touch pipe extends to the guide shell; the layered sealing mechanism includes a sliding filling tooth and an axially movable torsion disk, and the torsion disk is connected to a rotatable rotating cylinder; wherein the touch tube is used to drive the rotating cylinder to rotate, so that the filling tooth slides outward, forming an isolated sealing space with the inner wall of the wellbore and the adjacent guide shell.

[0006] In some feasible embodiments, the layered fracturing device further includes: a pressing ring arranged in the rotating cylinder and an offset wall cooperating with the pressing ring, the offset wall meshing with the offset gear in the guide shell, and an extrusion spring is sleeved on the outer surface of the offset wall.

[0007] In some achievable embodiments, the offset wall includes: two oppositely arranged semi-cylindrical components, one side of the semi-cylindrical component is flat, and the other side is provided with teeth and meshes with the offset gear, and the planes of the two semi-cylindrical components are slidably connected.

[0008] In some feasible embodiments, a spiral guide rail is provided on the inner side of the rotating cylinder, a pressing ring is slidably connected to the spiral guide rail, and an end face of the pressing ring abuts against an end of the touch tube; wherein the axial movement of the touch tube is converted into the rotational movement of the rotating cylinder by the pressing ring.

[0009] In some feasible embodiments, the impact column includes: an outer shell, fixedly connected to the surface of the injection shell; an impact pin, slidably arranged in the outer shell, the impact pin including an impact end and a driving end; a force storage spring, sleeved on the impact pin, and located in the outer shell; wherein, the impact pin extends into the injection shell, the driving end of the impact pin is a guide bevel, and the guide bevel slides with the extrusion disk.

[0010] In some feasible embodiments, the extrusion disk can be axially slidably arranged in the injection shell; the outer peripheral surface of the extrusion disk forms an inclined sliding fit with the driving end of the impact pin; wherein, when the extrusion disk moves axially in the injection shell, the axial movement is converted into radial movement of the impact pin through the inclined sliding fit.

[0011] In some practicable embodiments, the inner hole diameters of the limiting rings of the multiple layered fracturing devices are different.

[0012] In some feasible embodiments, the guide shell includes: a first limiting ring and a second limiting ring coaxially connected, a first fan-shaped slide groove is arrayed at one end of the first limiting ring away from the second limiting ring, a second fan-shaped slide groove is arrayed at one end of the second limiting ring away from the first limiting ring, and the first fan-shaped slide groove and the second fan-shaped slide groove are staggered in the circumferential direction; a frame shell, covering the outer circumference of the first limiting ring and the second limiting ring, a hollow cavity is formed inside the frame shell, and a plurality of through holes are provided on its circumferential side wall; wherein the first fan-shaped slide groove and the second fan-shaped slide groove together constitute a composite guide track for guiding the movement of the filling tooth.

[0013] In some feasible embodiments, the filling tooth is a fan-shaped key structure, and one side end face of the filling tooth is slidingly connected to the end face of the first limiting ring or the second limiting ring; a convex key is provided on the surface of the filling tooth, and the filling tooth is slidingly connected to the torsion disk through the convex key, and rotating the torsion disk can drive the filling tooth to slide along the first fan-shaped groove or the second fan-shaped groove.

[0014] In some feasible embodiments, a plurality of arcuate slots are arranged in an array on the torsion disk, and the plurality of arcuate slots are sleeved on the convex keys of the filling teeth; each arcuate slot forms a sliding fit with the convex key on the corresponding filling tooth.

[0015] Compared with the related art, this application has the following beneficial technical effects:

[0016] The coalbed methane well stratified fracturing string device provided in the present application provides a ball limiting ring on the surface of the extrusion disk so that the dropped blocking ball can stay at a specific position and cause a blockage. The extrusion disk is pushed by liquid pressure to compress the reset spring. By installing linkage teeth and opposing racks and cooperating with each other, the guide shells and filling teeth on both sides are triggered to form an isolated and sealed space. The extrusion disk continuously compresses the reset spring so that the fracturing fluid can be discharged from the injection shell into the enclosed space of the filling teeth, thereby producing a fracturing effect. The effect of automatic fracturing can be achieved by filling a blocking ball of appropriate size and continuously injecting fracturing fluid, thereby solving the problem that the coalbed methane well stratified fracturing requires complicated operation and construction.

[0017] The coalbed methane well stratified fracturing string device is installed with linked teeth and opposing racks. When the single-side extrusion disk is pushed by pressure, the touch tubes at both ends can be triggered and extended. The trigger rods at both ends simultaneously push the pressing rings at both ends of the injection shell, so that the two sets of torsion disks and the rotating cylinder are simultaneously pushed and rotated, and the filling teeth are pushed out from the inside of the guide shell to form a space isolated at one end, thereby forming stratified fracturing. The sealing mechanism in the same layer is triggered simultaneously to form a sealed space, which solves the problem that the separation devices at both ends of the same layer need to be triggered one by one, which may easily cause triggering errors and fail to seal the space.

[0018] This coalbed methane well stratified fracturing string device adjusts the force with which the squeeze disc pushes the impact pins by replacing the force-accumulating spring. The impact pins are only pushed out when the pressure inside the injection shell reaches a specified level. By placing the impact pins under pressure, the impact pins impact the wellbore wall, allowing the fracturing direction to be determined downhole, effectively controlling the pressure and direction of the fracturing fluid's downhole spray.

[0019] Additional aspects and advantages of the present application will become apparent in the following description or may be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 A schematic diagram of the structure of the injection shell in one embodiment of the present application is shown;

[0022] Figure 2 A schematic structural diagram of a coalbed methane well stratified fracturing string device in one embodiment of the present application is shown;

[0023] Figure 3 A schematic diagram of the internal structure of the injection shell in one embodiment of the present application is shown;

[0024] Figure 4 A schematic diagram of the structure of an extrusion disk in one embodiment of the present application is shown;

[0025] Figure 5 A schematic diagram of the structure of opposing racks in one embodiment of the present application is shown;

[0026] Figure 6 A schematic diagram of the impact column structure in one embodiment of the present application is shown;

[0027] Figure 7 A schematic diagram of the guide housing structure in one embodiment of the present application is shown;

[0028] Figure 8 A schematic diagram of the filling tooth structure in one embodiment of the present application is shown;

[0029] Figure 9 A schematic structural diagram of a torsion disk in one embodiment of the present application is shown;

[0030] Figure 10 A schematic diagram of the staggered wall structure in one embodiment of the present application is shown.

[0031] in, Figures 1 to 10 The corresponding relationship between the reference numerals and component names is as follows:

[0032] 100 injection shell, 102 injection port, 110 impact column, 112 outer shell, 114 storage spring, 116 impact pin, 120 positioning ring, 130 linkage tooth, 140 opposing rack, 150 extrusion disk, 152 ball limit ring, 160 touch tube, 170 return spring, 180 transition tube, 190 guide shell, 192 first limit ring, 194 second limit ring, 196 frame shell, 200 filling tooth, 210 torsion disk, 220 rotating cylinder, 230 pressing ring, 240 offset wall, 260 offset gear, 270 extrusion spring, 280 connecting tube. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned objects, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other in the absence of conflict.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0035] Refer to the following Figures 1 to 10 A coalbed methane well stratified fracturing string device according to some embodiments of the present application is described.

[0036] like Figure 1 、 Figure 2 、 Figure 3 and Figure 5 As shown, the present application provides a layered fracturing string device for a coalbed methane well, comprising: a plurality of layered fracturing devices connected in sequence along the axial direction of the wellbore, the layered fracturing device comprising: a fracturing injection assembly, comprising an injection shell 100 provided with an injection port 102, a positioning ring 120 and a linkage tooth 130 provided inside the injection shell 100, and an impact column 110 provided on the injection shell 100; a two-way drive assembly, comprising an opposing rack 140 engaged with the linkage tooth 130, the opposing rack 140 slidingly cooperates with the positioning ring 120, and the two ends of the opposing rack 140 are respectively connected to an extrusion disk 150, a touch tube 160 is fixedly connected to the surface of the extrusion disk 150, and a reset spring 170 is sleeved on the outer side of the touch tube 160. The spring 170 is located in the injection shell 100; the ball limit ring 152 is arranged on the extrusion disk 150, and is used to limit the stopping position of the inserted blocking ball to achieve layer isolation; the transition pipe 180 is arranged at both ends of the injection shell 100, and the two ends of the transition pipe 180 are respectively connected to the injection shell 100 and the guide shell 190, and the touch tube 160 extends to the guide shell 190; the layered sealing mechanism includes a sliding filling tooth 200 and an axially movable torsion disk 210, and the torsion disk 210 is connected to a rotatable rotating cylinder 220; wherein, the touch tube 160 is used to drive the rotating cylinder 220 to rotate, so that the filling tooth 200 slides outward, forming an isolated sealing space with the inner wall of the wellbore and the adjacent guide shell 190.

[0037] The present application provides a stratified fracturing string device for a coalbed methane well, comprising multiple stratified fracturing devices sequentially connected along the axial direction of the wellbore. The stratified fracturing device comprises a fracturing jet assembly, a bidirectional drive assembly, a ball limiting ring 152, a transition pipe, and a stratified sealing mechanism. By providing multiple stratified fracturing devices sequentially connected along the axial direction of the wellbore, precise fracturing of different layers of the coalbed methane well can be achieved, improving the relevance and effectiveness of the fracturing operation and helping to fully release the coalbed methane resources in each layer.

[0038] The setting of the ball limiting ring 152 can limit the stopping position of the inserted blocking ball, thereby reliably realizing layer isolation, ensuring that the fracturing fluid acts accurately on the target layer, avoiding interlayer crossflow, and improving the fracturing effect.

[0039] The fracturing injection assembly includes an injection shell 100, which is equipped with an injection port 102 and an impact column 110. When the pressure inside the injection shell 100 reaches the required level, fracturing fluid is ejected from the injection port 102 to perform a fracturing operation, enhancing the coal seam's transformation effect. The impact column 110 is used to damage the wellbore wall and control the starting direction of the fracturing process.

[0040] The opposing racks 140 in the bidirectional drive assembly mesh with the linkage gears 130. Once the blocking ball is in place, subsequent actions are automatically triggered through structures such as the squeeze disc 150 and the touch tube 160. The touch tube 160 extends to the guide housing 190 and drives the rotating cylinder 220 to rotate, causing the filling teeth 200 to slide outward, forming an isolated and sealed space with the inner wall of the wellbore and the adjacent guide housing 190. This achieves automated and efficient interlayer sealing, reduces manual intervention, and improves operational efficiency.

[0041] The coalbed methane well stratified fracturing string device provided in the present application, by arranging a ball limiting ring 152 on the surface of the extrusion disk 150, enables the launched blocking ball to stay at a specific position and cause a blockage, and the extrusion disk 150 is pushed by the liquid pressure to compress the reset spring 170, and by installing the linkage tooth 130 and the opposing rack 140 and cooperating with each other, the guide shells 190 and the filling teeth 200 on both sides are triggered to form an isolated and sealed space, and the extrusion disk 150 continuously compresses the reset spring 170 so that the fracturing fluid can be discharged from the injection shell 100 into the enclosed space of the filling teeth 200, so that it produces a fracturing effect, achieving the effect of completing automatic fracturing by filling a blocking ball of appropriate size and continuously injecting fracturing fluid, thereby solving the problem that the stratified fracturing of coalbed methane wells requires complicated operation and construction.

[0042] The coalbed methane well layered fracturing string device is installed with a linkage tooth 130 and an opposing rack 140. When the single-side squeeze disk 150 is pushed by pressure, the touch tubes 160 at both ends can be triggered and extended, so that the two sets of torsion disks 210 and the rotating cylinder 220 are pushed to rotate at the same time, and the filling teeth 200 are pushed out from the inside of the guide shell 190 to form a space isolated at one end, thereby forming layered fracturing, achieving the effect of simultaneously triggering the sealing mechanism in the same layer to form a sealed space, and solving the problem that the separation devices at both ends of the same layer need to be triggered one by one, which is easy to cause triggering errors and fail to seal the space.

[0043] like Figure 3 ,like Figure 9 and Figure 10 As shown, in some embodiments provided in the present application, the layered fracturing device further includes: a pressing ring 230 provided in the rotating cylinder 220 and an offset wall 240 cooperating with the pressing ring 230, the offset wall 240 is engaged with the offset gear 260 in the guide shell 190, and an extrusion spring 270 is sleeved on the outer surface of the offset wall 240.

[0044] In this embodiment, the layered fracturing device further includes a pressing ring 230, an offset wall 240, an offset gear 260, and a compression spring 270. The offset wall 240 is fixedly connected to the surface of the pressing ring 230, and the offset wall 240 is slidably connected to the inner circumference of the guide housing 190. The offset gear 260 is rotatably connected to the inner circumference of the guide housing 190, and the offset gear 260 meshes with the offset wall 240. The compression spring 270 is sleeved on the outer surface of the offset wall 240 and is disposed inside the rotating cylinder 220.

[0045] The pressing ring 230 cooperates with the offset wall 240, allowing it to exert force on the offset wall 240 when the contact tube 160 drives the rotating cylinder 220 to rotate. A compression spring 270 is sleeved on the outer surface of the offset wall 240. During the rotation of the rotating cylinder 220 and the movement of the offset wall 240, the compression spring 270 provides a certain degree of elastic cushioning and restoring effect. The pressing ring 230, the offset wall 240, the offset gear 260, and the compression spring 270 together form a power transmission and conversion system, converting the linear motion of the contact tube 160 into rotation of the rotating cylinder 220, thereby achieving a sliding seal for the filling teeth 200.

[0046] like Figure 10 As shown, in some embodiments provided in the present application, the offset wall 240 includes: two oppositely arranged semi-cylindrical components, one side of the semi-cylindrical component is flat, and the other side is provided with teeth and meshes with the offset gear 260, and the planes of the two semi-cylindrical components are slidably connected.

[0047] In this embodiment, the offset wall 240 comprises two semi-cylindrical members. The end surfaces of the two semi-cylindrical members are both arc-shaped and together form a circular tube. One side of the semi-cylindrical member is flat, and the other side is provided with teeth that mesh with the offset gear 260. The flat surfaces of the two semi-cylindrical members are slidably connected to each other. The outer surface of the offset wall 240 is slidably connected to the inner circumference of the guide housing 190. When pushed, the two semi-cylindrical members can be driven by the offset gear 260 to achieve interlocking movement, causing the two semi-cylindrical members to slide in opposite directions, achieving precise power transmission and motion control.

[0048] like Figure 3 and Figure 9 As shown, in some embodiments provided in the present application, a spiral guide rail is provided on the inner side of the rotating cylinder 220, the pressing ring 230 is slidably connected to the spiral guide rail, and the end face of the pressing ring 230 abuts against the end of the touch tube 160; wherein, the axial movement of the touch tube 160 is converted into the rotational movement of the rotating cylinder 220 through the pressing ring 230.

[0049] In this embodiment, when the touch tube 160 moves axially, its end pushes the pressing ring 230, and the pressing ring 230 slides along the spiral guide rail inside the rotating cylinder 220, accurately converting the axial linear motion into the rotational motion of the rotating cylinder 220. The power transmission is efficient and the conversion process is stable, ensuring the coordinated operation of the various components of the device.

[0050] The spiral guide rail is integrated into the inner side of the rotating cylinder 220, and the pressure ring 230 cooperates with the contact tube 160. The overall structure is compact and space-saving, facilitating installation and deployment in limited underground space and improving the device's applicability. The sliding cooperation between the spiral guide rail and the pressure ring 230 ensures smooth movement, reduces impact and wear between components, lowers the risk of failure, extends the device's service life, and reduces maintenance costs.

[0051] like Figure 6 As shown, in some embodiments provided herein, the impact column 110 includes: a housing 112 fixedly connected to the surface of the ejection housing 100; an impact pin 116 slidably disposed within the housing 112, the impact pin 116 including an impact end and a drive end; and a force storage spring 114 sleeved around the impact pin 116 and located within the housing 112. The impact pin 116 extends into the ejection housing 100, and the drive end of the impact pin 116 serves as a guide ramp that slidably engages with the extrusion disk 150.

[0052] In this embodiment, the impact column 110 includes a housing 112, an impact pin 116, and a force storage spring 114. By replacing the force storage spring 114, the force with which the squeeze disc 150 pushes the impact pin 116 can be adjusted. The impact pin 116 is only ejected when the pressure inside the injection housing 100 reaches a specified level. By placing the impact pin 116 under pressure, the impact pin 116 impacts the wellbore wall, enabling the fracturing direction to be determined downhole, thereby controlling the pressure and direction of the fracturing fluid ejection downhole.

[0053] The guide bevel at the driving end of the impact pin 116 slides with the squeeze plate 150, precisely translating the axial motion of the squeeze plate 150 into the sliding motion of the impact pin 116. By controlling the travel distance and speed of the squeeze plate 150, the timing and force of the impact of the impact pin 116 can be precisely controlled, ensuring that the impact is applied to key locations in the coal seam, thereby improving the targeted and effective fracturing.

[0054] Impact pin 116 is slidably mounted within housing 112. After a single impact, force-accumulating spring 114 automatically resets impact pin 116, making the device reusable. The impact of impact column 110 and the jet fracturing action of injection port 102 synergize to alter the coal seam from various angles, further enhancing the fracturing effect.

[0055] like Figure 4 and Figure 6As shown, in some embodiments provided in the present application, the extrusion disk 150 can be axially slidably arranged in the injection shell 100; the outer peripheral surface of the extrusion disk 150 forms an inclined sliding fit with the driving end of the impact pin 116; wherein, when the extrusion disk 150 moves axially in the injection shell 100, the axial motion is converted into radial motion of the impact pin 116 through the inclined sliding fit.

[0056] In this embodiment, the outer circumference of the squeeze plate 150 slides in conjunction with the inclined surface of the driving end of the impact pin 116, efficiently converting the axial motion of the squeeze plate 150 within the ejection housing 100 into radial motion of the impact pin 116. This conversion method features a simple structure and direct power transmission, reducing energy loss and improving motion conversion efficiency. This ensures that the impact pin 116 can quickly and powerfully complete its impact action, enhancing the crushing effect on targets such as coal seams.

[0057] The axial movement distance and speed of the squeeze plate 150 are controllable, allowing the radial movement amplitude and impact force of the impact pins 116 to be precisely adjusted through the inclined surface. This inclined surface sliding fit ensures smooth movement between the squeeze plate 150 and the impact pins 116, reducing vibration and shock caused by unstable movement and improving the stability and reliability of the device. This stable movement ensures normal operation of the device in complex downhole environments, ensuring smooth stratified fracturing operations.

[0058] In some embodiments provided in the present application, the inner hole diameters of the limiting rings of multiple layered fracturing devices are different.

[0059] In this embodiment, stopper rings with different inner diameters can accommodate different-sized blocking balls. During stratified fracturing operations, blocking balls of corresponding sizes are deployed for different layers, and the stopper rings precisely define their resting positions, achieving reliable layer isolation. This ensures that the fracturing fluid is precisely applied to the target layer, preventing interlayer crossflow, improving the fracturing effect in each layer, and enhancing the overall production efficiency of the coalbed methane well. It also adapts to different well and coal seam conditions, enhancing the device's applicability.

[0060] like Figure 7 As shown, in some embodiments provided in the present application, the guide shell 190 includes: a first limiting ring 192 and a second limiting ring 194 coaxially connected, a first fan-shaped slide groove is arrayed at one end of the first limiting ring 192 away from the second limiting ring 194, a second fan-shaped slide groove is arrayed at one end of the second limiting ring 194 away from the first limiting ring 192, and the first fan-shaped slide groove and the second fan-shaped slide groove are staggered in the circumferential direction; a frame shell 196, covering the outer circumference of the first limiting ring 192 and the second limiting ring 194, a hollow cavity is formed inside the frame shell 196, and a plurality of through holes are provided on its circumferential side wall; wherein, the first fan-shaped slide groove and the second fan-shaped slide groove together constitute a composite guide track for guiding the movement of the filling tooth 200.

[0061] In this embodiment, the composite guide track formed by the staggered arrangement of the first fan-shaped chute and the second fan-shaped chute provides a precise and stable movement path for the filling tooth 200. The filling tooth 200 can accurately move along the predetermined trajectory during the extension process, effectively avoiding jamming or offset, and ensuring the reliability of the interlayer seal. The coaxially connected first limit ring 192, the second limit ring 194 and the frame shell 196 are combined to form a solid overall structure. The frame shell 196 covers the outer periphery and forms a hollow cavity, which not only improves the compressive strength of the guide shell 190, but also buffers the impact force in the complex environment underground, reduces the risk of structural deformation, and extends the service life of the device.

[0062] The through-holes in the circumferential sidewalls of the frame shell 196 allow fluids like fracturing fluid to pass smoothly, reducing fluid resistance and improving fracturing efficiency. The filling teeth 200 extend outward through the through-holes in the frame shell 196, precisely sealing the interlayers or supporting the wellbore, preventing fluid crossflow and maintaining wellbore stability. The stable and reliable extension of the filling teeth 200 through the through-holes reduces the likelihood of failure or anomalies caused by structural issues, improving the reliability and safety of the device and ensuring smooth operation.

[0063] The combination of the composite guide rail and the frame shell 196 enables the guide shell 190 to adapt to complex well conditions such as different well diameters and formation pressures, ensuring that the filling teeth 200 can still operate reliably in harsh environments, thereby improving the adaptability and success rate of layered fracturing operations.

[0064] like Figure 8 and Figure 9 As shown, in some embodiments provided in the present application, the filling tooth 200 is a fan-shaped key structure, and one side end face of the filling tooth 200 is slidingly connected to the end face of the first limiting ring 192 or the second limiting ring 194; a convex key is provided on the surface of the filling tooth 200, and the filling tooth 200 is slidingly connected to the torsion disk 210 through the convex key. Rotating the torsion disk 210 can drive the filling tooth 200 to slide along the first fan-shaped groove or the second fan-shaped groove.

[0065] In this embodiment, the fan-shaped key structure is adapted to the first fan-shaped slide groove and the second fan-shaped slide groove, and one side end face of the filling tooth 200 is slidably connected to the end face of the limiting ring, and can slide precisely along the preset track, ensuring that the filling tooth 200 is accurately positioned and moves smoothly during the extension or retraction process, thereby achieving reliable interlayer sealing and avoiding sealing failure due to position deviation.

[0066] A convex key is provided on the surface of the filling tooth 200 and is slidably connected to the torsion disk 210. When the torsion disk 210 is rotated, the convex key can efficiently and stably transmit the rotational power of the torsion disk 210 to the filling tooth 200, so that the filling tooth 200 slides along the fan-shaped groove, ensuring the sensitivity and accuracy of the device's movement.

[0067] The filling teeth 200 of the fan-shaped key structure cooperate closely with the limit ring, torsion plate 210 and other components. The overall structure is compact and occupies little space, which is convenient for installation and use in the limited space underground, thereby improving the integration and space utilization of the device.

[0068] like Figure 9 As shown, in some embodiments provided in the present application, a plurality of arcuate grooves are arrayed on the torsion disk 210 , and the plurality of arcuate grooves are sleeved on the convex keys of the filling teeth 200 ; each arcuate groove forms a sliding fit with the convex key on the corresponding filling tooth 200 .

[0069] In this embodiment, the arcuate grooves on the torsion plate 210 form a sliding fit with the keyways of the filling teeth 200, converting the rotational motion of the torsion plate 210 into the telescopic motion of the filling teeth 200. This allows for precise and controllable movement of the filling teeth 200, improving the accuracy and reliability of layered fracturing operations. The array layout of multiple arcuate grooves and filling teeth 200 enables synchronized movement of the multiple filling teeth 200, achieving reliable interlayer sealing and preventing seal failures caused by inconsistent local motion.

[0070] The curved chute directly fits over the key of the filling tooth 200, eliminating the need for additional transmission components. This compact, space-saving design facilitates installation and operation within the limited space available underground. This sliding fit reduces energy loss during power transmission, improving transmission efficiency and ensuring that the rotational force of the torsion plate 210 is efficiently converted into movement of the filling tooth 200. The shape and angle of the curved chute can be adjusted to suit different filling tooth 200 motion trajectories and operational requirements.

[0071] In a specific embodiment, Figures 1 to 10As shown, the present application provides a stratified fracturing string device for coalbed methane wells. It includes an injection shell 100, with an injection port 102 fixedly connected to and extending through the surface of the injection shell 100, and an impact column 110 fixedly connected to and extending through the surface of the injection shell 100. A positioning ring 120 is fixedly connected to the inside of the injection shell 100, and a linkage tooth 130 is rotatably connected to the inside of the injection shell 100. Opposing racks 140 are meshed on the surface of the linkage tooth 130, and the opposing racks 140 are slidably connected to the positioning ring 120. The ends of the two sets of opposing racks 140 facing away from each other are fixedly connected to a squeeze disk 150. The impact column 110 is composed of a housing 112, a force storage spring 114, and an impact pin 116. The outer shell 112 is fixedly connected to the surface of the injection shell 100. An impact pin 116 is slidably connected to the inside of the outer shell 112. A force storage spring 114 is sleeved on the surface of the impact pin 116. The force storage spring 114 is located inside the outer shell 112. The end of the impact pin 116, away from the outer shell 112, extends through the injection shell 100. The end of the impact pin 116 on the inside of the injection shell 100 is a guide ramp. The impact pin 116 has a pointed end, and the guide ramp on the other end slides in contact with the extrusion disk 150. The impact column 110 supports the impact pin 116 via the force storage spring 114, which slows the sliding of the extrusion disk 150. The impact pin 116 is only ejected when the pressure inside the injection shell 100 reaches a specified level. The extrusion of the impact pin 116 damages the wellbore wall, thereby controlling the initial direction of the fracturing process.

[0072] A touch tube 160 is fixedly connected to the surface of the extrusion plate 150. There are two groups of opposing racks 140, which are symmetrically located on the outer side of the linkage tooth 130 and meshed with it. The end faces of the opposing racks 140 are connected to the extrusion plate 150. A limiting ball ring 152 is set on the surface of the extrusion plate 150. The inner hole diameter of each group of limiting ball rings 152 is different. The opposing racks 140 can use the linkage teeth 130 to achieve linkage, so that the two groups of opposing racks 140 can move in opposite directions.

[0073] A return spring 170 is sleeved on the outside of the touch tube 160, and the outer peripheral surface of the extrusion disk 150 is slidably connected to the inner wall of the injection shell 100. The outer peripheral surface of the extrusion disk 150 is in sliding contact with the impact pin 116 of the impact column 110. The extrusion disk 150 can be pushed by the ball limit ring 152 to slide inside the injection shell 100, so that the touch tube 160 is pushed and the impact column 110 is squeezed at the same time.

[0074] The return spring 170 is inside the injection shell 100, and the two ends of the injection shell 100 are fixedly connected to the transition tube 180. The transition tube 180 is wrapped around the outside of the touch tube 160, and the end face of the transition tube 180 is fixedly connected to the guide shell 190, and the filling tooth 200 is slidably connected to the inside of the guide shell 190. The guide shell 190 is in the shape of a circular ring as a whole. The guide shell 190 consists of a first limiting ring 192, a second limiting ring 194 and a frame shell 196. The first limiting ring 192 and the second limiting ring 194 are circular rings with two end faces connected. The end of the first limiting ring 192 away from the second limiting ring 194 is provided with an array of fan-shaped grooves, and the end of the second limiting ring 194 away from the first limiting ring 192 is also provided with a fan-shaped groove. The fan-shaped grooves provided in the first limiting ring 192 and the second limiting ring 194 have the same shape but different angles. The outer surfaces of the first limiting ring 192 and the second limiting ring 194 are fixedly connected to the frame shell 196. The inner side of the frame shell 196 is an empty shell, and the outer peripheral surface is provided with a through hole. The guide shell 190 has the function of guiding the movement of the filling tooth 200 and providing support for it.

[0075] A torsion disk 210 is sleeved on the surface of the filling tooth 200. The filling tooth 200 has a fan-shaped key shape. One side wall of the filling tooth 200 is slidingly connected to the surface of the first limiting ring 192 or the second limiting ring 194. A convex key is provided on the surface of the filling tooth 200 and is slidingly connected to the torsion disk 210. The filling tooth 200 can extend from the inside of the guide shell 190. By extending two groups of staggered filling teeth 200 at the same time, a disc blockage is formed, forming a sealed space on the inside of the well wall to facilitate layered fracturing.

[0076] The torsion plate 210 is slidably connected to the inner side of the guide shell 190. The torsion plate 210 has an annular flat plate shape. An array of arc-shaped grooves is provided on the surface of the torsion plate 210. The arc-shaped grooves of the torsion plate 210 are sleeved on the outer side of the convex key on the surface of the filling tooth 200. The torsion plate 210 pushes the filling tooth 200 by rotating, so that the filling tooth 200 can extend from the inner side of the guide shell 190 or be retracted into it.

[0077] The torsion disk 210 is fixedly connected to the side away from the filling tooth 200 with a rotating cylinder 220, and a pressing ring 230 is slidingly connected to the inside of the rotating cylinder 220. The rotating cylinder 220 is rotatably connected to the transition tube 180. The rotating cylinder 220 has a cylindrical shape, and a spiral guide rail is provided on the inside of the rotating cylinder 220. The pressing ring 230 is slidably connected to the spiral guide rail inside the rotating cylinder 220. The pressing ring 230 is in contact with the touch tube 160. The rotating cylinder 220 can be pushed to rotate when the pressing ring 230 slides axially. The rotation of the rotating cylinder 220 drives the torsion disk 210 to rotate and adjust the extension or retraction of the filling tooth 200.

[0078] The surface of the pressing ring 230 is fixedly connected to a staggered wall 240, which is slidably connected to the inner circumference of the guide shell 190. The inner circumference of the guide shell 190 is rotatably connected to a staggered gear 260, which meshes with the staggered wall 240. The outer surface of the staggered wall 240 is sleeved with an extrusion spring 270. The staggered wall 240 consists of two parts, and the end faces of the two parts of the staggered walls 240 are both arc-shaped and together form a circular tube shape. One side of the staggered wall 240 is flat, and the other side is provided with teeth and meshes with the staggered gear 260. The planes of the two groups of staggered walls 240 are slidably connected to each other, and the outer surfaces of the staggered walls 240 are slidably connected to the inner circumference of the guide shell 190. When pushed, the two groups of staggered walls 240 can be driven by the staggered gear 260 to realize linkage, so that the two groups of staggered walls 240 slide in opposite directions. The extrusion spring 270 is located inside the rotating cylinder 220 , and the two connected sets of guide shells 190 are connected via a connecting pipe 280 .

[0079] The specific implementation principle of the coalbed methane well stratified fracturing string device is as follows: During use, the device is first deployed into a predetermined wellbore. A blocking ball of an appropriate diameter is placed into the pipe, and the fracturing fluid is injected, carrying the blocking ball to the appropriate ball stop ring 152, thereby forming the device. As the fracturing fluid is continuously filled, the ball stop ring 152 pushes the extrusion plate 150 to move inside the injection shell 100. The extrusion plate 150 pushes the opposing rack 140, which in turn rotates the linkage gear 130, causing the two sets of opposing racks 140 to move toward their respective ends. This causes the extrusion plates 150 at both ends to move simultaneously, compressing the return spring 170 and causing the contact tubes 160 at both ends of the injection shell 100 to slide away from each other, contacting and squeezing the pressing ring 230. The pressing ring 230 is compressed, driving the offset wall 240 to move. Driven by the offset gear 260, the offset walls 240 on both sides move together. Because the offset wall 240 is slidably connected to the guide housing 190, the pressing ring 230 moves axially. Simultaneously, the guide rail inside the rotating cylinder 220 causes the pressing ring 230 to rotate the rotating cylinder 220, causing the rotating cylinder 220 to rotate the torsion plate 210. As the torsion plate 210 rotates, the arc-shaped groove inside the torsion plate 210 pushes the filling teeth 200 out of the inside of the guide housing 190. The filling teeth 200, which pass through the inside of the first and second limiting rings 192 and 194, simultaneously slide out through the through-holes of the guide housing 190, allowing the guide housing 190 to cooperate with the filling teeth 200 to clamp and seal the inner wall of the wellbore. By installing guide housings 190 and filling teeth 200 on both sides of the injection housing 100, a layered sealed space is formed between them. As the fracturing fluid continues to be injected, the ball-stop ring 152, carrying the blocking ball, continues to push downward and forward. The impact pin 116 is squeezed by the squeeze plate 150, causing the impact pin 116 to push against the compressed storage spring 114 and extend from the inside of the housing 112 to damage the wellbore wall. By pre-adjusting the spring constant of the storage spring 114, the fluid pressure that triggers the impact pin 116 during fracturing fluid injection can be adjusted. The squeeze plate 150 compresses the return spring 170, allowing the injection port 102 on the surface of the injection housing 100 to connect with the pressurized fracturing fluid and eject it. By deploying blocking balls of different sizes, in conjunction with ball-stop rings 152 of varying diameters, controlled fracturing of various layers can be achieved. When resetting is required, the internal pressure of the pipeline can be released, and the return spring 170 and the squeeze spring 270 can be removed to push the corresponding mechanism to reset.

[0080] In this application, the term "plurality" refers to two or more, unless otherwise specified. Terms such as "installed," "connected," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean fixed, removable, or integrally connected; and "connected" can mean directly or indirectly through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0081] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0082] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A coalbed methane well stratified fracturing string device, characterized in that: include: A plurality of layered fracturing devices connected in sequence along the axial direction of the wellbore, the layered fracturing device comprising: The fracturing injection assembly comprises an injection shell provided with an injection port, a positioning ring and linkage gears are provided inside the injection shell, and an impact column is provided on the injection shell; A bidirectional drive assembly includes opposing racks meshing with the linkage teeth, the opposing racks slidingly cooperating with the positioning ring, the two ends of the opposing racks respectively connected to the extrusion disk, the surface of the extrusion disk is fixedly connected to the touch tube, the outer side of the touch tube is sleeved with a return spring, and the return spring is located in the injection shell; A ball limiting ring is provided on the squeeze plate and is used to limit the stopping position of the inserted blocking ball to achieve interval isolation; A transition pipe is provided at both ends of the injection shell, the two ends of the transition pipe are respectively connected to the injection shell and the guide shell, and the touch pipe extends to the guide shell; A layered sealing mechanism includes a slidably arranged filling tooth and an axially movable torsion plate, wherein the torsion plate is connected to a rotatable rotating cylinder; The touch tube is used to drive the rotating cylinder to rotate, so that the filling teeth slide outward to form an isolated and sealed space with the inner wall of the wellbore and the adjacent guide shell.

2. The coalbed methane well stratified fracturing string device according to claim 1, characterized in that: The layered fracturing device further includes: a pressing ring arranged in the rotating cylinder and a dislocation wall cooperating with the pressing ring, the dislocation wall meshing with the dislocation gear in the guide housing, and an extrusion spring sleeved on the outer surface of the dislocation wall.

3. The coalbed methane well stratified fracturing string device according to claim 2, characterized in that: The offset wall includes: two semi-cylindrical components arranged opposite to each other, one side of the semi-cylindrical component is flat, and the other side is provided with teeth and meshes with the offset gear, and the planes of the two semi-cylindrical components are slidably connected.

4. The coalbed methane well stratified fracturing string device according to claim 3, characterized in that: A spiral guide rail is provided on the inner side of the rotating cylinder, the pressing ring is slidably connected to the spiral guide rail, and the end surface of the pressing ring abuts against the end of the touch tube; The axial movement of the touch tube is converted into the rotational movement of the rotating cylinder through the pressing ring.

5. The coalbed methane well stratified fracturing string device according to claim 1, characterized in that: The impact column comprises: a housing fixedly connected to the surface of the injection shell; an impact nail slidably disposed in the housing, the impact nail comprising an impact end and a driving end; A force storage spring, sleeved on the impact nail and located inside the housing; The impact nail extends into the injection shell, and the driving end of the impact nail is a guide slope, and the guide slope is in sliding cooperation with the extrusion disk.

6. The coalbed methane well stratified fracturing string device according to claim 5, characterized in that: The extrusion disc can be axially slidably arranged in the injection shell; the outer peripheral surface of the extrusion disc forms an inclined sliding fit with the driving end of the impact nail; wherein, when the extrusion disc moves axially in the injection shell, the axial motion is converted into radial motion of the impact nail through the inclined sliding fit.

7. The coalbed methane well stratified fracturing string device according to any one of claims 1 to 6, characterized in that: The inner hole diameters of the limiting rings of the multiple layered fracturing devices are different.

8. The coalbed methane well stratified fracturing string device according to any one of claims 1 to 6, characterized in that: The guide housing comprises: A first limiting ring and a second limiting ring are coaxially connected, wherein a plurality of first sector-shaped chutes are arranged in an array at one end of the first limiting ring away from the second limiting ring, and a plurality of second sector-shaped chutes are arranged in an array at one end of the second limiting ring away from the first limiting ring, wherein the first sector-shaped chutes and the second sector-shaped chutes are staggered in the circumferential direction; a frame shell, covering the outer circumference of the first limiting ring and the second limiting ring, wherein a hollow cavity is formed inside the frame shell, and a plurality of through holes are provided on the circumferential side wall thereof; The first sector-shaped chute and the second sector-shaped chute together constitute a composite guide track for guiding the movement of the filling tooth.

9. The coalbed methane well stratified fracturing string device according to claim 8, characterized in that: The filling tooth is a fan-shaped key structure, and one end surface of the filling tooth is slidably connected to the end surface of the first limiting ring or the second limiting ring; A convex key is provided on the surface of the filling tooth, and the filling tooth is slidably connected to the torsion plate through the convex key. Rotating the torsion plate can drive the filling tooth to slide along the first sector-shaped chute or the second sector-shaped chute.

10. The coalbed methane well stratified fracturing string device according to claim 9, characterized in that: A plurality of arc-shaped sliding grooves are arranged in an array on the torsion plate, and the plurality of arc-shaped sliding grooves are sleeved on the convex keys of the filling teeth; Each of the arc-shaped sliding grooves forms a sliding fit with the convex key on the corresponding filling tooth.

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