Multichannel wellbore cleaning device

Abstract

This invention provides a multi-channel wellbore cleaning device, comprising: an upper connector, a cleaning module, and a lower connector connected in sequence. The cleaning module includes: a housing, and a mandrel unit and a channel conversion unit arranged from the inside out within the housing; wherein the housing has several flow holes; the mandrel unit includes an upper mandrel and a lower mandrel; wherein the upper mandrel has several first bypass holes; the channel conversion unit enables the first bypass holes and the flow holes on the housing to be either connected or closed. In the closed state, fluid flowing into the upper mandrel can flow into the lower mandrel and exit from the lower connector; in the connected state, fluid flowing into the upper mandrel can sequentially exit from the first bypass holes and the flow holes on the housing. The beneficial effects of this invention include: controlling the switching of different working channel positions using fluid excitation, resulting in fast response speed and minimal influence from well inclination angle; flexible installation position; improved drilling efficiency; and shortened drilling time.

Description

Technical Field

[0001] This invention relates to downhole tools for oil and gas drilling, and in particular, to a multi-channel wellbore cleaning device. Background Technology

[0002] During coiled tubing operations, the wellbore typically contains a large amount of sediment and fouling. Using a direct-through method for high-volume well cleaning can severely damage the connected tool string. Furthermore, during coiled tubing drilling, if the lower grinding shoe's water channel becomes blocked, a normal wellbore circulation channel cannot be established. This poses a significant risk to tripping or milling operations, necessitating the rapid establishment of bypass circulation to prevent complex accidents. In deep and ultra-deep wells with extended reach, large cuttings beds often accumulate in the stabilizing and horizontal sections. Conventional small-diameter drill string circulation methods are insufficient for timely cleaning and may cause drill string jamming or affect well completion quality. Typically, pump flushing is used to generate turbulence and clean the wellbore. However, small-diameter mud motors and measurement-while-drilling tools cannot meet the pump speed requirements for achieving turbulence, making efficient wellbore cleaning extremely difficult, especially in highly deviated and horizontal wells. Drilling personnel typically address these issues through short trips, well cleaning operations, drill bit changes, and other cleaning procedures. These methods may be effective to some extent, but they require a lot of time for drilling and undrilling, which reduces production efficiency.

[0003] Chinese patent CN106321013A discloses a single-ball throwing type infinite circulation valve, mainly comprising a housing, a valve piston, and a rotation control body. A housing nozzle is mounted on the housing, and the valve piston and rotation control body are installed inside the housing, allowing them to slide along the axial direction of the housing. Openings inside the housing, valve piston, and rotation control body form a main fluid channel. In the downward valve position, the valve piston blocks the housing nozzle, cutting off the connection between the main channel and the wellbore annulus; in the upward valve position, the valve piston releases its blockage of the housing nozzle, allowing fluid to flow along the main channel through the housing nozzle to the wellbore annulus. The rotation control body has a control groove track that engages with a fixed pin, guiding the valve piston between the downward and upward valve positions.

[0004] Chinese Patent Publication No. CN207761600U discloses a downhole circulating well cleaning tool, comprising a circulating well cleaning tool body, a pressure relief sub, and a switch housing connected in sequence. The circulating well cleaning tool body includes a hollow circulating outer sleeve, a hollow mandrel fitted inside the circulating outer sleeve, and a switch assembly. The pressure relief sub is a hollow cavity structure connected to the bottom of the circulating outer sleeve, wherein the cavity connects to a drilling fluid flow channel within the circulating outer sleeve, and an opening is provided on the side wall of the pressure relief sub, with a pressure relief valve installed within the opening. The switch housing includes a housing outer sleeve and an inner cylinder located within the housing outer sleeve. The housing outer sleeve is connected to the bottom of the pressure relief sub, and the switch body and valve ball are housed within the inner cylinder, which has a hollow structure.

[0005] Both patents above achieve the purpose of switching tool states by infinitely cycling the valve in different forms. However, as an infinitely cycling valve controlled by ball throwing, it has obvious drawbacks, just like other ball throwing tools. First, it requires precise ball throwing technology, and misthrowing increases operational risks. Second, the ball throwing switch has a slow response speed, and the drill string combination cannot be flexibly selected due to the ball throwing effect; the inclination measurement process can only use MWD and cannot perform mechanical inclination measurement. Third, the need to design a special ball throwing control switch increases the complexity of the tool's internal structure, thereby reducing the tool's reliability and increasing its maintenance difficulty. Summary of the Invention

[0006] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. The purpose of this invention is to provide a well-washing tool that uses fluid excitation to control the switching of positions of different working channels, has a fast response speed, and is less affected by the well inclination angle.

[0007] To achieve the above objectives, the present invention provides a multi-channel wellbore cleaning device.

[0008] The device includes an upper connector, a cleaning module, and a lower connector connected in sequence.

[0009] The cleaning module includes: a housing, and a spindle unit and a channel conversion unit arranged from the inside out within the housing; wherein, the housing has several flow holes; the spindle unit includes an upper spindle and a lower spindle; wherein, the upper end of the upper spindle is connected to an upper connector, and the upper spindle has a first axial hole and several first bypass holes, the first axial hole having openings at both the upper and lower ends of the upper spindle; the first bypass holes are formed on the shaft of the upper spindle and communicate with the first axial hole; the lower end of the lower spindle is connected to a lower connector, and the lower spindle has a second axial hole and several second bypass holes, the second axial hole being a blind hole with its opening forming the lower end face of the lower spindle, the second bypass holes being formed on the shaft of the lower spindle and communicating with the second axial hole. The channel conversion unit enables the first bypass holes and the flow holes on the housing to be in a connected or closed state, wherein, in the closed state, the first axial hole and the second bypass holes are connected, and in the connected state, the first axial hole and the second bypass holes are not connected.

[0010] Optionally, the channel conversion unit may include a shifting component and a shifting piston. The shifting component is fixed to the inner wall of the housing and protrudes inward. The shifting piston may be partially or completely fitted onto the shaft of the upper mandrel, and the shifting piston has several third bypass holes, at least one first shifting groove, and at least one second shifting groove. In the closed state, the shifting component is located in the first shifting groove, and the third bypass holes are not connected to the first bypass holes; in the connected state, the shifting component is located in the second shifting groove, and the first bypass holes, the third bypass holes, and the flow holes on the housing are sequentially connected. The shifting piston also has at least one first limiting groove and at least one second limiting groove longitudinally formed; the number of first limiting grooves and first shifting grooves are the same and correspond one-to-one, and the first limiting groove and the corresponding first shifting groove are located on the same axis; the number of second limiting grooves and second shifting grooves are the same and correspond one-to-one, and the second limiting groove and the corresponding second shifting groove are located on the same axis; when the limiting member is located at the top position of the first limiting groove, the shifting member is located in the first shifting groove; when the limiting member is located at the top position of the second limiting groove, the shifting member is located in the second shifting groove.

[0011] Optionally, the upper mandrel may have several pressure holes communicating with the first axial hole on its shaft; the pressure holes may be located above the shifting piston and the first bypass hole. Fluid flowing into the upper mandrel can flow out from the pressure holes and apply downward pressure to the shifting piston. The at least one first shifting groove and the at least one second shifting groove are alternately arranged, both the first shifting groove and the second shifting groove are vertically formed, and the top of the first shifting groove is lower than the top of the second shifting groove. The shifting piston may also have the same number of first connecting grooves as the first shifting grooves, each first connecting groove being located between adjacent first shifting grooves and second shifting grooves and having its two ends communicating with the first shifting groove and the second shifting groove, respectively.

[0012] Optionally, the channel conversion unit may include a shifting component and a shifting piston. The shifting component is fixed to the inner wall of the housing and protrudes inward. The shifting piston is partially or completely fitted onto the shaft of the upper mandrel, and has several third bypass holes, several fourth bypass holes, at least one first shifting groove, at least one second shifting groove, and at least one third shifting groove. The fourth bypass holes are positioned higher than the third bypass holes. In the closed state, the shifting component is located in the first shifting groove, and neither the third nor the fourth bypass holes are connected to the first bypass hole. In the connected state, the shifting component is located in the second shifting groove, and the first bypass hole, the third bypass hole, and the flow hole on the housing are sequentially connected; or, the shifting component is located in the third shifting groove, and the first bypass hole, the fourth bypass hole, and the flow hole on the housing are sequentially connected.

[0013] Optionally, the upper mandrel may have several pressure holes communicating with the first axial hole on its shaft; the pressure holes are located above the shifting piston and the first bypass hole; fluid flowing into the upper mandrel can flow out from the pressure holes and apply downward pressure to the shifting piston. The number of first, second, and third shifting slots is the same, and the first, second, and third shifting slots are arranged alternately and are all vertically oriented. The top of the first shifting slot is lower than the top of the second shifting slot, and the top of the second shifting slot is lower than the top of the third shifting slot. The shifting piston also has the same number of first, second, and third connecting slots as the first shifting slots; each first connecting slot is located between adjacent first and second shifting slots and its two ends are respectively connected to both; each second connecting slot is located between adjacent second and third shifting slots and its two ends are respectively connected to both; each third connecting slot is located between adjacent third shifting slots and first shifting slots and its two ends are respectively connected to both.

[0014] Optionally, the number of the first, second, and third transposition slots is the same. The first connecting slot may include a first inclined slot segment, a first longitudinal slot segment, and a second inclined slot segment; wherein the top of the first inclined slot segment communicates with the second transposition slot, and the connection point is higher than the bottom of the second transposition slot; the bottom of the first inclined slot segment communicates with the top of the first longitudinal slot segment; the bottom of the second inclined slot segment communicates with the first longitudinal slot segment, and the connection point is lower than the top of the first longitudinal slot segment; the top of the second inclined slot segment communicates with the bottom of the first transposition slot. The second connecting slot may include a third inclined slot segment, a second longitudinal slot segment, and a fourth inclined slot segment; wherein the top of the third inclined slot segment communicates with the third transposition slot, and the connection point is higher than the bottom of the third transposition slot; the bottom of the third inclined slot segment communicates with the top of the second longitudinal slot segment; the bottom of the fourth inclined slot segment communicates with the second longitudinal slot segment, and the connection point is lower than the top of the second longitudinal slot segment; the top of the fourth inclined slot segment communicates with the bottom of the second transposition slot. The third connecting groove may include a fifth inclined groove segment, a third longitudinal groove segment, and a sixth inclined groove segment; wherein, the top of the fifth inclined groove segment is connected to the first transposition groove, and the connection position between the two is higher than the bottom position of the first transposition groove; the bottom of the fifth inclined groove segment is connected to the top of the third longitudinal groove segment; the bottom of the sixth inclined groove segment is connected to the third longitudinal groove segment, and the connection position between the two is lower than the top of the third longitudinal groove segment; the top of the sixth inclined groove segment is connected to the bottom of the third transposition groove.

[0015] Optionally, the shifting piston may also have at least one second limiting groove and at least one third limiting groove longitudinally formed; the number of second limiting grooves is the same as the number of second shifting grooves and they correspond one-to-one, and the second limiting grooves and their corresponding second shifting grooves are located on the same axis; the number of third limiting grooves is the same as the number of third shifting grooves and they correspond one-to-one, and the third limiting grooves and their corresponding third shifting grooves are located on the same axis. The channel conversion unit may also include a limiting member, which is fixed to the inner wall of the housing and protrudes inward, and the limiting member is located in the second limiting groove or the third limiting groove; when the limiting member is located at the top position in the second limiting groove, the shifting member is located in the second shifting groove; when the limiting member is located at the top position in the third limiting groove, the shifting member is located in the third shifting groove.

[0016] Alternatively, the second and third limiting grooves can be formed at the lower part of the shifting piston, and both of them form a groove on the lower end surface of the shifting piston. When the shifting member is located in the first shifting groove, the limiting member can limit the lower end surface of the shifting piston.

[0017] Optionally, the shifting piston may also have at least one longitudinally formed first limiting groove; the number of first limiting grooves and the number of first shifting grooves are the same and they correspond one-to-one, and the first limiting grooves and the corresponding first shifting grooves are located on the same axis; when the limiting member is located at the top position of the first limiting groove, the shifting member is located in the first shifting groove. The first, second and third limiting grooves are connected by transverse grooves.

[0018] Alternatively, the shifting piston may include a first piston section and a second piston section connected vertically; the first and second piston sections are connected by threads and are prevented from rotating relative to each other circumferentially by a fixing member;

[0019] The third and fourth bypass holes can be disposed on the first piston section; the first, second, and third transposition grooves can be disposed on the second piston section.

[0020] Alternatively, a buffer spring and a buffer piston may be installed in the first piston section.

[0021] Alternatively, the channel switching unit may further include a return spring, which is installed between the lower section of the second piston section and the lower spindle.

[0022] Optionally, when the first bypass hole, the third bypass hole, and the flow hole on the housing are connected in sequence, the device can perform backflow operation; when the first bypass hole, the fourth bypass hole, and the flow hole on the housing are connected in sequence, the device can perform well washing operation.

[0023] Alternatively, sealing elements may be provided between the housing and the shifting piston, between the shifting piston and the upper mandrel, and between the shifting piston and the lower mandrel.

[0024] Alternatively, the housing may also be provided with multiple pressure balancing holes.

[0025] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0026] (1) The multi-channel well cleaning device of the present invention uses fluid excitation to control the position switching of different working channels. It has a fast response speed and is less affected by the well inclination angle. It can be installed in a flexible position and can use a variety of inclination measurement methods.

[0027] (2) Fluid excitation is adopted, and the displacement of the pump is adjusted to make the shifting piston produce different axial displacement and circumferential rotation under the action of the displacement. A special shifting and reset mechanism is configured to solve the problem of the limitation of the number of times the existing circulation valve can be opened and the need to repeatedly start and stop the drilling to reset the valve.

[0028] (3) It adopts a water jet design with large displacement, and can achieve the purpose of forward and reverse sand flushing when used with sand flushing tools. It can provide a well washing tool with strong sand flushing and sand carrying capabilities at the same time.

[0029] (4) The high-pressure cleaning hole design can effectively remove dirt and dust adhering to the well wall, so as to achieve the purpose of thoroughly cleaning the well.

[0030] (5) The upper and lower spindles are fixed relative to the housing. The switching and bypass opening and closing are achieved by the circumferential rotation and axial movement of the switching piston. There is no jamming of the spindle itself, and the switching structure has high reliability.

[0031] (6) It is pressure sensitive, easy to control the opening and closing of the bypass, and easy to judge the working mode of the tool by the pressure status on the ground.

[0032] (7) Fewer parts, compact structure, no need to design ball seats, switches and other control mechanisms, reducing processing, production and maintenance costs. Attached Figure Description

[0033] The above and other objects and features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0034] Figure 1 A schematic diagram of the overall structure of a multi-channel well cleaning device according to an exemplary embodiment of the present invention is shown;

[0035] Figure 2 A schematic diagram of the straight-through mode of a multi-channel well cleaning device according to an exemplary embodiment of the present invention is shown;

[0036] Figure 3 A schematic diagram of the bypass backflow mode of the multi-channel wellbore cleaning device of Exemplary Embodiment 1 of the present invention is shown;

[0037] Figure 4 A schematic diagram of the structure of the displacement piston in exemplary embodiment 1 of the present invention is shown;

[0038] Figure 5 A schematic diagram of the bypass well-washing mode of the multi-channel wellbore cleaning device of exemplary embodiment 2 of the present invention is shown;

[0039] Figure 6 A schematic diagram of the structure of the displacement piston in exemplary embodiment 2 of the present invention is shown;

[0040] Figure 7 A schematic diagram of the overall structure of the multi-channel well cleaning device of exemplary embodiment 3 of the present invention is shown;

[0041] Figure 8A schematic diagram of the straight-through mode of the multi-channel wellbore cleaning device of exemplary embodiment 3 of the present invention is shown;

[0042] Figure 9 A schematic diagram of the backflow mode of the multi-channel wellbore cleaning device of exemplary embodiment 3 of the present invention is shown;

[0043] Figure 10 A schematic diagram of the well-washing mode of the multi-channel wellbore cleaning device of exemplary embodiment 3 of the present invention is shown;

[0044] Figure 11 A schematic diagram of the transposition piston of exemplary embodiment 3 of the present invention is shown.

[0045] Explanation of reference numerals in the attached figures:

[0046] A-Upper connector;

[0047] B-Cleaning module;

[0048] 1-Shell, 11-Flow hole, 12-Pressure balance hole;

[0049] 2-Mandrel unit, 21-Upper mandrel, 211-First axial hole, 212-First bypass hole, 213-Pressure hole; 22-Lower mandrel, 221-Second axial hole, 222-Second bypass hole;

[0050] 3-Channel conversion unit; 31-Transfer element; 32-Transfer piston; 321-Third bypass hole; 322-Fourth bypass hole; 323-Buffer piston; 324-Buffer spring.

[0051] 331-First transposition slot, 332-Second transposition slot, 333-Third transposition slot, 334-First connecting slot, 335-Second connecting slot, 336-Third connecting slot, 337-First limiting slot, 338-Second limiting slot, 339-Third limiting slot;

[0052] 34-Limiting component;

[0053] 35 - Return spring;

[0054] C-bottom connector. Detailed Implementation

[0055] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention.

[0056] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0057] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0058] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0059] Exemplary Example 1

[0060] This exemplary embodiment provides a multi-channel wellbore cleaning device. The device has two operating modes: direct flow and backflow. The following describes the process in conjunction with... Figures 1 to 4 To describe this device.

[0061] In this embodiment, as Figure 1 As shown, the device includes an upper connector A, a cleaning module B, and a lower connector C connected in sequence. The cleaning module B includes a housing 1, and a spindle unit 2 and a channel conversion unit 3 arranged in a direction from the inside out within the housing 1.

[0062] like Figures 1 to 2 As shown, the housing 1 has several flow holes 11, which are channels for fluid to flow out of the housing 1.

[0063] The mandrel unit 2 includes an upper mandrel 21 and a lower mandrel 22. The upper end of the upper mandrel 21 is threadedly connected to the upper connector A. The upper mandrel 21 has a first axial hole 211 and a first bypass hole 212. The first axial hole 211 is a through hole, with openings formed at both its upper and lower ends. The first axial hole 211 serves as a channel for fluid flow within the upper mandrel 21. The first bypass hole 212 is formed on the shaft of the upper mandrel 21 and communicates with the first axial hole 211, allowing fluid to flow out of the upper mandrel 21 through the first bypass hole 212.

[0064] The lower end of the lower mandrel 22 is threadedly connected to the lower connector C. The lower mandrel 22 has a second axial hole 221 and a second bypass hole 222. The second axial hole 221 is a blind hole, with an opening at the lower end of the lower mandrel 22 through which fluid can flow out. The second bypass hole 222 is formed on the shaft of the lower mandrel 22 and communicates with the second axial hole 221, allowing fluid to flow into the lower mandrel 22.

[0065] The channel conversion unit 3 enables the first bypass hole 212 and the flow hole 11 on the housing 1 to be either connected or closed. In the closed state, fluid flowing out from the lower end of the upper mandrel 21 can flow into the lower mandrel 22 and out from the lower connector C. That is, fluid flowing out from the lower end of the first axial hole 211 can flow into the second axial hole 221 through the second bypass hole 222 and finally out from the lower connector C; this state is the straight-through mode. In the connected state, fluid flowing into the upper mandrel 21 can flow out sequentially from the first bypass hole 212 and the flow hole 11 on the housing 1. That is, the gap between the lower end of the upper mandrel 21 and the upper end of the lower mandrel 22 can be blocked by the channel conversion unit 3. Fluid in the first axial hole 211 flows out through the first bypass hole 212 and the flow hole 11 for backflow; this state is the backflow mode.

[0066] In this embodiment, as Figures 1 to 4 As shown, the channel conversion unit 3 may include a shift piston 32 and a shift member 31.

[0067] The shifting component 31 is fixed to the inner wall of the housing 1 and protrudes inward. The shifting piston 32 can be partially or completely sleeved on the shaft of the upper spindle 21. The shifting piston 32 is provided with a third bypass hole 321, a first shifting groove 331 and a second shifting groove 332.

[0068] As one embodiment of the present invention, the displacement piston 32 can be an integral structure.

[0069] In another embodiment of the present invention, the shifting piston 32 may further include a first piston section and a second piston section connected vertically. The first and second piston sections are connected by threads and their relative circumferential rotation is prevented by a fixing member (e.g., a locking screw). A third bypass hole 321 is provided on the first piston section; first and second shifting grooves are provided on the second piston section. Setting the shifting piston 32 as a first and second piston section facilitates the installation and disassembly of the device, reducing the difficulty of processing and assembly.

[0070] In this embodiment, in the pass-through mode, such as Figure 2 As shown, the fluid flows out from the first axial hole 211 of the upper mandrel 21, and through the gap between the lower mandrel 22 and the shift piston 32, flows into the second axial hole 221 through the second bypass hole 222 and finally flows out from the lower connector C.

[0071] In this embodiment, a buffer spring 324 and a buffer piston 323 are installed in the first piston section. In the straight-through mode, the first bypass hole 212 and the buffer piston 323 form a seal, preventing liquid from flowing out of the upper mandrel through the first bypass hole 212 and flowing to the second bypass hole 222. When the buffer piston 323 moves to the lower end, it can form a seal with the upper end of the lower mandrel 22, closing the lower flow channel (corresponding to the backflow mode). The function of the buffer spring 324 is to reduce the impact force on the surface when the buffer piston 323 contacts the top of the upper end of the lower mandrel 22, preventing damage to the surface of the parts.

[0072] In this embodiment, the upper end of the lower mandrel 22 is set as a closed end, so that the flow channel of the lower mandrel 22 can be better sealed in the backflow mode. In the backflow mode, the lower end of the upper mandrel 21 and the upper end of the lower mandrel 22 will not contact each other, and the upper end of the lower mandrel 22 and the buffer piston 323 are sealed by a sealing ring, closing the flow channel. At this time, no fluid will flow into the lower mandrel 22 and flow out from it.

[0073] In this embodiment, in the closed state (i.e., through mode), the shifting member 31 is located in the first shifting groove 331, and the third bypass hole 321 is not connected to the first bypass hole 212; in the connected state (i.e., backflow mode), the shifting member 31 is located in the second shifting groove 332, and the first bypass hole 212, the third bypass hole 321 and the flow hole 11 on the housing 1 are connected in sequence.

[0074] In this embodiment, as Figure 2As shown, a pressure hole 213 communicating with the first axial hole 211 can be opened on the shaft of the upper mandrel 21; the pressure hole 213 can be located above the shift piston 32 and the first bypass hole 212. The fluid flowing into the upper mandrel 21 can flow out through the pressure hole 213 and apply downward pressure to the shift piston 32, providing power for the shift piston 32 to move downward. Through the pressure hole 213, the opening and closing of the bypass channel can be easily controlled, and the working mode of the tool can be easily determined on the ground by the pressure state.

[0075] like Figure 4 As shown, the first shifting groove 331 and the second shifting groove 332 are alternately arranged. Both the first shifting groove 331 and the second shifting groove 332 are vertically formed, and the top of the first shifting groove 331 is lower than the top of the second shifting groove 332. The shifting piston 32 may also have the same number of first connecting grooves 334 as the first shifting grooves 331. Each first connecting groove 334 is located between adjacent first shifting grooves 331 and second shifting grooves 332, and its two ends are connected to the first shifting groove 331 and the second shifting groove 332, respectively. The shifting piston 32 also has the same number of second connecting grooves 335 as the second shifting grooves 332. Each second connecting groove 335 is located between adjacent second shifting grooves 332 and first shifting grooves 331, and its two ends are connected to the first shifting groove 331 and the second shifting groove 332, respectively. The shifting member 31 can slide in the shifting grooves and connecting grooves to change the position of the shifting piston 32, thereby controlling the working mode of the device.

[0076] In this embodiment, the number of the first, second, and third transposition slots is the same.

[0077] In this embodiment, as Figure 4 As shown, the first connecting groove 334 may include a first inclined groove segment, a first longitudinal groove segment, and a second inclined groove segment. The top of the first inclined groove segment communicates with the second transposition groove 332, and the communication position is higher than the bottom of the second transposition groove 332. The bottom of the first inclined groove segment communicates with the top of the first longitudinal groove segment. The bottom of the second inclined groove segment communicates with the first longitudinal groove segment, and the communication position is lower than the top of the first longitudinal segment. The top of the second inclined groove segment communicates with the bottom of the first transposition groove 331. This ensures that, even with increased fluid flow, the transposition member 31 can move from the first transposition groove 331 into the second transposition groove 332.

[0078] The second connecting groove 335 may include a third inclined groove segment, a second longitudinal groove segment, and a fourth inclined groove segment. The top of the third inclined groove segment communicates with the first transposition groove 331, and the connection point is higher than the bottom of the first transposition groove 331. The bottom of the third inclined groove segment communicates with the top of the second longitudinal groove segment. The bottom of the fourth inclined groove segment communicates with the second longitudinal groove segment, and the connection point is lower than the top of the second longitudinal segment. The top of the fourth inclined groove segment communicates with the bottom of the second transposition groove 332. This ensures that when the fluid displacement is reduced, the transposition member 31 can return from the second transposition groove 332 to the first transposition groove 331.

[0079] The upper and lower spindles are fixed relative to the housing 1. The switching and bypass opening and closing are achieved by the circumferential rotation and axial movement of the switching piston 32. There is no jamming of the spindle itself, and the switching structure has high reliability.

[0080] In this embodiment, as Figure 2 and Figure 3 As shown, the channel switching unit 3 may also include a reset spring 35, which is installed at the lower end of the switching piston 32; the reset spring 35 can restore the switching piston 32 to its initial position.

[0081] In this embodiment, sealing elements can be provided between the housing 1 and the shifting piston 32, between the shifting piston 32 and the upper mandrel 21, and between the shifting piston 32 and the lower mandrel 22. The sealing elements can effectively prevent fluid from seeping into another component, ensuring that fluid can only flow through the various through holes in different components.

[0082] In this embodiment, the housing 1 may also be provided with a plurality of pressure balancing holes 12. The pressure balancing holes 12 can balance the pressure changes inside the lower cavity of the switching piston during its upward and downward movements, thereby extending the service life of the tool.

[0083] In this embodiment, as Figure 4 As shown, the shifting piston 32 may also have a longitudinally opened second limiting groove 338; the number of second limiting grooves 338 and the number of second shifting grooves 332 are the same and correspond one-to-one, and the second limiting grooves 338 and the corresponding second shifting grooves 332 are located on the same axis.

[0084] In this embodiment, the channel conversion unit 3 may further include a limiting member 34, which is fixed to the inner wall of the housing 1 and protrudes inward, and is located in the second limiting groove 338. When the limiting member 34 is located at the top position in the second limiting groove 338, the switching member 31 is located in the second switching groove 332.

[0085] In this embodiment, the second limiting groove 338 can be opened at the lower part of the shifting piston 32, and a groove is formed on the lower end surface of the shifting piston 32. When the shifting member 31 is located in the first shifting groove 331, the limiting member 34 can limit the lower end surface of the shifting piston 32.

[0086] The second limiting groove 338 can limit the downward movement distance of the shift piston 32, preventing the shift piston 32 from moving too far downward in the bypass return operation mode, which may cause the third bypass hole 321 to fail to connect with the first bypass hole 212 and the flow hole 11.

[0087] Of course, this embodiment is not limited to this; the shifting piston 32 may also have a longitudinally formed first limiting groove 337; the number of first limiting grooves 337 and the number of first shifting grooves 331 are the same and they correspond one-to-one, and the first limiting grooves 337 and the corresponding first shifting grooves 331 are located on the same axis. When the limiting member 34 is located at the top position of the first limiting groove 337, the shifting member 31 is located in the first shifting groove 331. The first and second limiting grooves are connected by a transverse groove.

[0088] In this embodiment, the central axis of the third bypass hole 321 and the central axis of the flow hole 11 intersect the axis of the housing 1 in different working positions.

[0089] In this embodiment, the angle between the central axis of the third bypass hole 321 and the central axis of the flow hole 11 and the axis of the housing 1 is between 70° and 110°. Further, the angle between the central axis of the third bypass hole 321 and the central axis of the flow hole 11 and the axis of the housing 1 is 90°.

[0090] In this embodiment, the third bypass hole 321 is used for backflow. When a larger backflow rate is selected, multiple bypass holes can be designed, such as 6-8, with diameters ranging from 13-19 mm, for example, 14 mm, 15 mm, 16 mm, 17 mm, and 18 mm. When a lower backflow rate is selected, fewer bypass holes can be designed, such as 3-4, with diameters ranging from 4-10 mm, for example, 5 mm, 6 mm, 8 mm, and 9 mm. The flow hole 11 is a cylindrical hole with a diameter ranging from 3 mm to 20 mm; for example, 5 mm, 6 mm, 8 mm, 12 mm, 15 mm, 17 mm, and 19 mm. Further, in this embodiment, the diameter of the third bypass hole 321 is 8 mm; the diameter of the flow hole 11 is 8 mm.

[0091] Specific working mode:

[0092] I. Direct Access Mode

[0093] In this embodiment, the straight-through mode of the multi-channel wellbore cleaning device is as follows: Figure 2 As shown.

[0094] When the pump is running, the upper end face of the shifting piston 32 is continuously subjected to the fluid pressure discharged from the pressure hole 213. At this time, the shifting member 31 is located in the first shifting groove 331 of the shifting piston 32, and the reset spring 35 is in a straight compression state.

[0095] Due to the constraints of the shifting component 31 and the shifting groove, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are circumferentially offset from each other. At the same time, due to the constraints of the shifting component 31 and the lower end face of the shifting piston 32, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are axially offset from each other.

[0096] Since the third bypass hole 321, the flow hole 11 and the first bypass hole 212 are all staggered in the circumferential and axial directions at this time, the bypass channel is closed. The fluid can only flow out through the first axial hole 211 of the upper mandrel 21, flow into the lower mandrel 22 through the second bypass hole 222, and then flow out through the second axial hole 221 of the lower mandrel 22 to the lower connector C.

[0097] II. Bypass Return Mode

[0098] In this embodiment, the bypass backflow mode of the multi-channel wellbore cleaning device is as follows: Figure 3 As shown.

[0099] In pump-on mode, fluid displacement increases. In backflow mode, fluid displacement is 1.5-3 times that in direct flow mode. The unit of displacement is MPL (liters per minute). Due to the continuous action of fluid pressure from pressure hole 213 on the upper end face of the shifting piston 32, the shifting member 31 is located in the second shifting groove 332 of the shifting piston 32, and the return spring 35 is in bypass compression state.

[0100] Constrained by the shifting member 31 and the shifting groove, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are circumferentially aligned with each other. At the same time, constrained by the shifting member 31 and the lower end face of the shifting piston 32, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are axially aligned with each other.

[0101] Since the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are aligned circumferentially and axially at this time, the bypass return flow channel is open. Fluid flows out through the first bypass hole 212, and then through the third bypass hole 321 and out of the flow hole 11, ultimately forming a large-volume return flow to return sediment and rock cuttings. The design of the high-volume water jet, combined with sand flushing tools, can achieve both forward and reverse sand flushing and well washing, possessing strong sand flushing and carrying capabilities simultaneously.

[0102] Exemplary Example 2

[0103] This exemplary embodiment provides a multi-channel wellbore cleaning device, which has two working modes: direct-flow and well-washing. The following describes the device in conjunction with... Figures 1 to 2 , Figures 5 to 6 To describe this device.

[0104] The multi-channel wellbore cleaning device provided in this embodiment is largely the same as the multi-channel wellbore cleaning device provided in Exemplary Embodiment 1, except that the shifting groove and limiting groove on the shifting piston 32 are different; the specific working modes are also different.

[0105] In this embodiment, as Figure 6 As shown, the second transposition groove and the second limiting groove are both higher than the second transposition groove and the second limiting groove in Exemplary Example 1.

[0106] Specific working mode:

[0107] I. Direct Access Mode

[0108] In this embodiment, the straight-through mode of the multi-channel wellbore cleaning device is as follows: Figure 2 As shown.

[0109] When the pump is running, the upper end face of the shifting piston 32 is continuously subjected to the fluid pressure discharged from the pressure hole 213. At this time, the shifting member 31 is located in the first shifting groove 331 of the shifting piston 32, and the reset spring 35 is in a straight compression state.

[0110] Due to the constraints of the shifting component 31 and the shifting groove, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are circumferentially offset from each other. At the same time, due to the constraints of the shifting component 31 and the lower end face of the shifting piston 32, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are axially offset from each other.

[0111] Since the third bypass hole 321, the flow hole 11 and the first bypass hole 212 are all staggered in the circumferential and axial directions at this time, the bypass channel is closed. The fluid can only flow out through the first axial hole 211 of the upper mandrel 21, flow into the lower mandrel 22 through the second bypass hole 222, and then flow out through the second axial hole 221 of the lower mandrel 22 to the lower connector C.

[0112] II. Bypass Well Washing Mode

[0113] In this embodiment, the bypass well-washing mode of the multi-channel wellbore cleaning device is as follows: Figure 5 As shown.

[0114] When the pump is running, the fluid displacement increases. In well-washing mode, the fluid displacement is 1.2-2 times that in straight-through mode. The unit of displacement is MPL (liters per minute). Due to the continuous action of the fluid pressure discharged from the pressure hole 213 on the upper end face of the shifting piston 32, the shifting component 31 is located in the second shifting groove 332 of the shifting piston 32, and the return spring 35 is in a bypass compression state.

[0115] Constrained by the shifting member 31 and the shifting groove, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are circumferentially aligned with each other. At the same time, constrained by the shifting member 31 and the lower end face of the shifting piston 32, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are axially aligned with each other.

[0116] Since the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are aligned circumferentially and axially at this time, the bypass well-washing channel is open. Fluid flows out through the first bypass hole 212, and then through the third bypass hole 321 and out of the flow hole 11, ultimately forming a high-pressure jet of fluid to clean the wellbore. The high-pressure cleaning hole design effectively removes dirt and dust adhering to the wellbore wall, achieving the purpose of thoroughly cleaning the wellbore.

[0117] Exemplary Example 3

[0118] This exemplary embodiment provides a multi-channel wellbore cleaning device, which has three working modes: direct flow, backflow, and well washing. The following describes the device in conjunction with... Figures 7 to 11 This embodiment will be described below.

[0119] The multi-channel wellbore cleaning device provided in this embodiment is as follows: Figure 7 As shown, it is largely the same as the multi-channel wellbore cleaning device provided in Exemplary Example 1, except that:

[0120] In this embodiment, as Figure 8 and Figure 11 As shown, the shifting piston 32 is provided with a third bypass hole 321, a fourth bypass hole 322, a first shifting groove 331, a second shifting groove 332 and a third shifting groove 333.

[0121] In one embodiment of the present invention, the shifting piston 32 may further include a first piston section and a second piston section connected vertically. The first and second piston sections are connected by threads and are prevented from rotating relative to each other in the circumferential direction by a fixing member. Third and fourth bypass holes are provided on the first piston section; first, second, and third shifting grooves are provided on the second piston section. Setting the shifting piston 32 as a first and second piston section facilitates the installation and disassembly of the device, reducing processing and assembly difficulties.

[0122] In the closed state, the switching member 31 is located in the first switching groove 331, and the third bypass hole 321 and the fourth bypass hole 322 are both offset from the first bypass hole 212; in the connected state, the switching member 31 is located in the second switching groove 332, and the first bypass hole 212, the third bypass hole 321 and the flow hole 11 on the housing 1 are connected in sequence; or, the switching member 31 is located in the third switching groove 333, and the first bypass hole 212, the fourth bypass hole 322 and the flow hole 11 on the housing 1 are connected in sequence.

[0123] In this embodiment, as Figure 11 As shown, the first, second, and third transposition slots are arranged alternately in sequence, and all three are vertically formed. The top of the first transposition slot 331 is lower than the top of the second transposition slot 332, and the top of the second transposition slot 332 is lower than the top of the third transposition slot 333. The transposition piston 32 also has the same number of first connecting slots 334, second connecting slots 335, and third connecting slots 336 as the first transposition slots 331. Each first connecting slot 334 is located between adjacent first transposition slots 331 and second transposition slots 332, and its two ends are connected to both of them. Each second connecting slot 335 is located between adjacent second transposition slots 332 and third transposition slots 333, and its two ends are connected to both of them. Each third connecting slot 336 is located between adjacent third transposition slots 333 and first transposition slots 331, and its two ends are connected to both of them.

[0124] In this embodiment, as Figure 11 As shown, the first connecting groove 334 may include a first inclined groove segment, a first longitudinal groove segment, and a second inclined groove segment. The top of the first inclined groove segment communicates with the second transposition groove 332, and the communication position is higher than the bottom of the second transposition groove 332. The bottom of the first inclined groove segment communicates with the top of the first longitudinal groove segment. The bottom of the second inclined groove segment communicates with the first longitudinal groove segment, and the communication position is lower than the top of the first longitudinal segment. The top of the second inclined groove segment communicates with the bottom of the first transposition groove 331. This ensures that, even with increased fluid flow, the transposition member 31 can move from the first transposition groove 331 into the second transposition groove 332.

[0125] In this embodiment, as Figure 11 As shown, the second connecting groove 335 may include a third inclined groove segment, a second longitudinal groove segment, and a fourth inclined groove segment. The top of the third inclined groove segment communicates with the third transposition groove 333, and the communication position between them is higher than the bottom of the third transposition groove 333. The bottom of the third inclined groove segment communicates with the top of the second longitudinal groove segment. The bottom of the fourth inclined groove segment communicates with the second longitudinal groove segment, and the communication position between them is lower than the top of the second longitudinal segment. The top of the fourth inclined groove segment communicates with the bottom of the second transposition groove 332. This ensures that, while further maintaining fluid flow rate, the transposition member 31 can move from the second transposition groove 332 into the third transposition groove 333.

[0126] In this embodiment, as Figure 11 As shown, the third connecting groove 336 may include a fifth inclined groove segment, a third longitudinal groove segment, and a sixth inclined groove segment. The top of the fifth inclined groove segment communicates with the first transposition groove 331, and the connection point is higher than the bottom of the first transposition groove 331. The bottom of the fifth inclined groove segment communicates with the top of the third longitudinal groove segment. The bottom of the sixth inclined groove segment communicates with the third longitudinal groove segment, and the connection point is lower than the top of the third longitudinal groove segment. The top of the sixth inclined groove segment communicates with the bottom of the third transposition groove 333. This ensures that, even with a reduced fluid displacement, the transposition member 31 can move from the third transposition groove 333 into the first transposition groove 331.

[0127] The shifting member 31 can slide in the first, second and third shifting grooves and the first, second and third connecting grooves to control the position of the shifting piston 32 and change the working mode of the device.

[0128] In this embodiment, as Figure 11 As shown, the shifting piston 32 may also have a longitudinally formed second limiting groove 338 and a third limiting groove 339. The number of second limiting grooves 338 is the same as the number of second shifting grooves 332, and they correspond one-to-one. The second limiting grooves 338 and their corresponding second shifting grooves 332 are located on the same axis. The number of third limiting grooves 339 is the same as the number of third shifting grooves 333, and they correspond one-to-one. The third limiting grooves 339 and their corresponding third shifting grooves 333 are located on the same axis.

[0129] In this embodiment, the channel conversion unit 3 may further include a limiting member 34, which is fixed to the inner wall of the housing 1 and protrudes inward. The limiting member 34 is located in the second limiting groove 338 or the third limiting groove 339. When the limiting member 34 is located at the top position in the second limiting groove 338, the switching member 31 is located in the second switching groove 332; when the limiting member 34 is located at the top position in the third limiting groove 339, the switching member 31 is located in the third switching groove 333.

[0130] In this embodiment, the second and third limiting grooves can be formed at the lower part of the shifting piston 32, and both of them form grooves on the lower end surface of the shifting piston 32. When the shifting member 31 is located in the first shifting groove 331, the limiting member 34 can limit the lower end surface of the shifting piston 32.

[0131] The second and third limiting grooves can limit the downward movement distance of the switching piston 32, preventing the third and fourth bypass holes 322 from failing to connect with the first bypass hole 212 and the flow hole 11 if the downward movement distance of the switching piston 32 is too far in the bypass backflow and bypass well washing working modes.

[0132] Of course, this embodiment is not limited to this; the shifting piston 32 may also have a longitudinally formed first limiting groove 337; the number of first limiting grooves 337 and first shifting grooves 331 are the same and correspond one-to-one, and the first limiting grooves 337 and the corresponding first shifting grooves 331 are located on the same axis. When the limiting member 34 is located at the top position of the first limiting groove 337, the shifting member 31 is located in the first shifting groove 331. The first, second and third limiting grooves are connected by a transverse groove.

[0133] In this embodiment, the third bypass hole 321 is used for backflow. When a larger discharge volume backflow is selected, multiple bypass holes can be designed, such as 6-8, and the diameter range is 13-19mm, such as 14mm, 15mm, 16mm, 17mm, and 18mm. When a lower discharge volume backflow is selected, fewer bypass holes can be designed, such as 3-4, and the diameter range is 4-10mm, such as 5mm, 6mm, 8mm, and 9mm. The fourth bypass hole 322 is used for well flushing. When a larger flushing rate is selected, multiple bypass holes can be designed, such as 6-8, with diameters ranging from 13-19 mm, for example, 14 mm, 15 mm, 16 mm, 17 mm, and 18 mm. When a lower flushing rate is selected, fewer bypass holes can be designed, such as 3-4, with diameters ranging from 4-10 mm, for example, 5 mm, 6 mm, 8 mm, and 9 mm. The flow hole 11 is a cylindrical hole with a diameter ranging from 3 mm to 20 mm; for example, 5 mm, 6 mm, 8 mm, 12 mm, 15 mm, 17 mm, and 19 mm. Further, in this embodiment, the diameter of the third bypass hole 321 is 8 mm; the diameter of the fourth bypass hole 322 is 8 mm; and the diameter of the flow hole 11 is 8 mm.

[0134] Specific working mode:

[0135] I. Direct Access Mode

[0136] In this embodiment, the straight-through mode of the multi-channel wellbore cleaning device is as follows: Figure 8 As shown.

[0137] When the pump is running, the upper end face of the shifting piston 32 is continuously subjected to the fluid pressure discharged from the pressure hole 213. At this time, the shifting member 31 is located in the first shifting groove 331 of the shifting piston 32, and the reset spring 35 is in a straight compression state.

[0138] Due to the constraints of the shifting component 31 and the shifting groove, the third bypass hole 321, the fourth bypass hole 322, the flow hole 11, and the first bypass hole 212 are circumferentially offset from each other. At the same time, due to the constraints of the shifting component 31 and the lower end face of the shifting piston 32, the third and fourth bypass holes, the flow hole 11, and the first bypass hole 212 are axially offset from each other.

[0139] Since the third bypass hole 321, the fourth bypass hole 322, the flow hole 11 and the first bypass hole 212 are all staggered in the circumferential and axial directions at this time, the bypass channel is closed. The fluid can only flow out through the first axial hole 211 of the upper mandrel 21, flow into the lower mandrel 22 through the second bypass hole 222, and then flow out of the lower connector C through the second axial hole 221 of the lower mandrel 22.

[0140] II. Bypass Return Mode

[0141] In this embodiment, the bypass backflow mode of the multi-channel wellbore cleaning device is as follows: Figure 9 As shown.

[0142] When the pump is running, the fluid displacement increases. In the backflow mode, the fluid displacement is 1.5-3 times that in the direct flow mode. Due to the continuous action of the fluid pressure discharged from the pressure hole 213 on the upper end face of the shifting piston 32, the shifting member 31 is located in the second shifting groove 332 of the shifting piston 32, and the return spring 35 is in the bypass compression state.

[0143] Constrained by the shifting member 31 and the shifting groove, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are circumferentially aligned with each other. At the same time, constrained by the shifting member 31 and the lower end face of the shifting piston 32, the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are axially aligned with each other.

[0144] Since the third bypass hole 321, the flow hole 11, and the first bypass hole 212 are aligned circumferentially and axially at this time, the bypass return flow channel is open. Fluid flows out through the first bypass hole 212, and then through the third bypass hole 321 and out of the flow hole 11, ultimately forming a large-volume return flow to return sediment and rock cuttings. The design of the high-volume water jet, combined with sand flushing tools, can achieve both forward and reverse sand flushing and well washing, possessing strong sand flushing and carrying capabilities simultaneously.

[0145] III. Bypass Well Washing Mode

[0146] In this embodiment, the bypass well-washing mode of the multi-channel wellbore cleaning device is as follows: Figure 10 As shown.

[0147] In pump-on mode, fluid discharge increases; in well-washing mode, fluid discharge is 1.2-2 times that in straight-through mode. After the backflow mode, because the upper end face of the shift piston 32 is still subjected to the continuous action of the fluid pressure discharged from the pressure hole 213, the shifting component 31 is located in the third shifting groove 333 of the shift piston 32, and the return spring 35 is in a bypass compression state.

[0148] Constrained by the shifting member 31 and the shifting groove, the fourth bypass hole 322, the flow hole 11, and the first bypass hole 212 are circumferentially aligned with each other. At the same time, constrained by the shifting member 31 and the lower end face of the shifting piston 32, the fourth bypass hole 322, the flow hole 11, and the first bypass hole 212 are axially aligned with each other.

[0149] Since the fourth bypass hole 322, the flow hole 11, and the first bypass hole 212 are aligned circumferentially and axially at this time, the bypass well-washing channel is open. Fluid flows out through the first bypass hole 212, and then through the fourth bypass hole 322 and the flow hole 11, ultimately forming a high-pressure jet of fluid to clean the wellbore. The high-pressure cleaning hole design effectively removes dirt and dust adhering to the wellbore wall, achieving thorough cleaning of the wellbore.

[0150] This invention employs fluid excitation, adjusting the pump displacement to induce different axial displacements and circumferential rotations in the shifting piston under the influence of the fluid flow. It also incorporates a dedicated shifting and resetting mechanism, solving the problems of limited opening times of existing circulation valves and the need for repeated tripping and resetting. Furthermore, it offers fast response speed, is less affected by well inclination angle, allows for flexible installation, and can be used with various inclination measurement methods. With fewer components and a compact structure, it eliminates the need for ball seats, switches, and other control mechanisms, reducing manufacturing and maintenance costs.

[0151] Although the invention has been described above in conjunction with exemplary embodiments, those skilled in the art will understand that various modifications and changes can be made to the exemplary embodiments of the invention without departing from the spirit and scope defined by the claims.

Claims

1. A multi-channel wellbore cleaning device, characterized in that, The device includes: an upper connector, a cleaning module, and a lower connector connected in sequence; The cleaning module includes: a housing, and a spindle unit and a channel conversion unit arranged inside the housing from the inside out; wherein, The casing has several flow holes; The mandrel unit includes an upper mandrel and a lower mandrel; wherein, the upper end of the upper mandrel is connected to an upper connector, and the upper mandrel has a first axial hole and several first bypass holes, the first axial hole having openings at both the upper and lower ends of the upper mandrel; the first bypass holes are formed on the shaft of the upper mandrel and communicate with the first axial hole; several pressure holes communicating with the first axial hole are formed on the shaft of the upper mandrel; the pressure holes are located above the shift piston and the first bypass holes; fluid flowing into the upper mandrel can flow out from the pressure holes and apply downward pressure to the shift piston; The lower end of the lower mandrel is connected to the lower connector. The lower mandrel has a second axial hole and several second bypass holes. The second axial hole is a blind hole and its opening forms the lower end face of the lower mandrel. The second bypass holes are opened on the shaft of the lower mandrel and communicate with the second axial hole. The channel conversion unit enables the first bypass hole and the flow hole on the housing to be in a connected or closed state. In the closed state, the first axial hole and the second bypass hole are connected, and in the connected state, the first axial hole and the second bypass hole are not connected. The channel conversion unit includes a transposition component and a transposition piston; wherein... The transposition component is fixed to the inner wall of the housing and protrudes inward; The shifting piston is partially or completely sleeved on the shaft body of the upper spindle. The shifting piston has several third bypass holes, several fourth bypass holes, at least one first shifting groove, at least one second shifting groove, and at least one third shifting groove. The fourth bypass hole is positioned higher than the third bypass hole. In the closed state, the transposition member is located in the first transposition groove, and neither the third bypass hole nor the fourth bypass hole is connected to the first bypass hole; In the connected state, the transposition component is located in the second transposition groove, and the first bypass hole, the third bypass hole, and the flow hole on the shell are connected in sequence. Fluid flows through the first bypass hole, the third bypass hole, and the flow hole to form a large-volume backflow to backflow sediment and rock cuttings; or, the transposition component is located in the third transposition groove, and the first bypass hole, the fourth bypass hole, and the flow hole on the shell are connected in sequence. Fluid flows through the first bypass hole, the fourth bypass hole, and the flow hole to form a high-pressure jet to clean the wellbore. The number of the first, second and third transposition slots is the same. The first, second and third transposition slots are arranged alternately in sequence and all three are vertically opened. The top of the first transposition slot is lower than the top of the second transposition slot, and the top of the second transposition slot is lower than the top of the third transposition slot. The shifting piston is also provided with the same number of first connecting slots, second connecting slots, and third connecting slots as the first shifting slots; each first connecting slot is located between adjacent first shifting slots and second shifting slots and its two ends are respectively connected to both of them; each second connecting slot is located between adjacent second shifting slots and third shifting slots and its two ends are respectively connected to both of them; each third connecting slot is located between adjacent third shifting slots and first shifting slots and its two ends are respectively connected to both of them. The shifting piston also has at least one second limiting groove and at least one third limiting groove that are longitudinally opened; the number of second limiting grooves is the same as the number of second shifting grooves and they correspond one-to-one, and the second limiting grooves and the corresponding second shifting grooves are located on the same axis; the number of third limiting grooves is the same as the number of third shifting grooves and they correspond one-to-one, and the third limiting grooves and the corresponding third shifting grooves are located on the same axis. The channel conversion unit further includes a limiting member, which is fixed to the inner wall of the housing and protrudes inward. The limiting member is located in a second limiting groove or a third limiting groove. When the limiting member is located at the top position in the second limiting groove, the shifting member is located in the second shifting groove. When the limiting member is located at the top position in the third limiting groove, the shifting member is located in the third shifting groove. The shifting piston also has at least one first limiting groove formed longitudinally; the number of first limiting grooves and first shifting grooves are the same and correspond one-to-one, and the first limiting groove and the corresponding first shifting groove are located on the same axis; when the limiting member is located at the top position of the first limiting groove, the shifting member is located in the first shifting groove. The first, second and third limiting grooves are connected by a transverse groove.

2. The multi-channel wellbore cleaning device according to claim 1, characterized in that, The number of the first, second, and third transposition slots is the same; The first connecting groove includes a first inclined groove segment, a first longitudinal groove segment, and a second inclined groove segment; wherein, the top of the first inclined groove segment is connected to the second transposition groove, and the connection position between the two is higher than the bottom position of the second transposition groove, and the bottom of the first inclined groove segment is connected to the top of the first longitudinal groove segment; the bottom of the second inclined groove segment is connected to the first longitudinal groove segment, and the connection position between the two is lower than the top of the first longitudinal groove segment, and the top of the second inclined groove segment is connected to the bottom of the first transposition groove. The second connecting groove includes a third inclined groove segment, a second longitudinal groove segment, and a fourth inclined groove segment; wherein, the top of the third inclined groove segment is connected to the third transposition groove, and the connection position between the two is higher than the bottom position of the third transposition groove, and the bottom of the third inclined groove segment is connected to the top of the second longitudinal groove segment; the bottom of the fourth inclined groove segment is connected to the second longitudinal groove segment, and the connection position between the two is lower than the top of the second longitudinal groove segment, and the top of the fourth inclined groove segment is connected to the bottom of the second transposition groove. The third connecting groove includes a fifth inclined groove segment, a third longitudinal groove segment, and a sixth inclined groove segment; wherein, the top of the fifth inclined groove segment is connected to the first transposition groove, and the connection position between the two is higher than the bottom position of the first transposition groove; the bottom of the fifth inclined groove segment is connected to the top of the third longitudinal groove segment; the bottom of the sixth inclined groove segment is connected to the third longitudinal groove segment, and the connection position between the two is lower than the top of the third longitudinal groove segment; the top of the sixth inclined groove segment is connected to the bottom of the third transposition groove.

3. The multi-channel wellbore cleaning device according to claim 1, characterized in that, The second and third limiting grooves are formed at the lower part of the shifting piston, and both of them form a groove on the lower end surface of the shifting piston. When the shifting member is located in the first shifting groove, the limiting member can limit the lower end surface of the shifting piston.

4. The multi-channel wellbore cleaning device according to claim 1, characterized in that, The shifting piston includes a first piston section and a second piston section connected vertically; the first and second piston sections are connected by threads and are prevented from rotating circumferentially relative to each other by a fixing member; The third and fourth bypass holes are provided on the first piston section; the first, second and third transposition grooves are provided on the second piston section.

5. The multi-channel wellbore cleaning device according to claim 4, characterized in that, A buffer spring and a buffer piston are installed inside the first piston section.

6. The multi-channel wellbore cleaning device according to claim 4, characterized in that, The channel conversion unit also includes a reset spring, which is installed between the lower section of the second piston section and the lower spindle.

7. The multi-channel wellbore cleaning device according to claim 1, characterized in that, Sealing elements are provided between the housing and the shifting piston, between the shifting piston and the upper mandrel, and between the shifting piston and the lower mandrel.

8. The multi-channel wellbore cleaning device according to claim 1, characterized in that, The housing is also provided with multiple pressure balancing holes.

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