Drill bit drive active clutch with helical locking function

Abstract

This invention provides a drill bit transmission active clutch with a helical locking function, comprising: a motor assembly; a clutch assembly connected to the lower end of the motor assembly, comprising: a housing, with a first reverse helix on the inner wall of the housing; a sliding toothed jaw disposed within the housing, with a second reverse helix on the outer wall of the sliding toothed jaw, the second reverse helix being adaptable to the first reverse helix; a drill bit connecting shaft; and a fixed toothed jaw; in a first state, the motor assembly drives the sliding toothed jaw to rotate, thereby driving the drill bit to rotate, the second reverse helix being at the upper end of the first reverse helix and forming an axial upward lock on the sliding toothed jaw; in a second state, the sliding toothed jaw disengages from the motor assembly and is adapted to engage with the fixed toothed jaw, the drill bit is driven to rotate by rotating the drill rod via a rotary table disposed at the wellhead, the second reverse helix being at the lower end of the first reverse helix and forming an axial downward lock on the sliding toothed jaw; the first state and the second state can be switched between each other.

Description

Technical Field

[0001] This invention belongs to the technical field of drilling and completion tools, specifically relating to a drill string drive active clutch with a helical locking function. Background Technology

[0002] Modern oil drilling mostly uses screw drill string assemblies, which integrate a motor assembly within the drill string. The motor assembly is a positive displacement motor, primarily composed of a rotor and a stator. The rotor is a helical alloy steel shaft, and the stator consists of an alloy steel tube and an internally bonded rubber cavity, converting the pressure energy of the drilling fluid into energy for the drill bit. Due to the characteristics of the motor assembly, when the rock-breaking torque exceeds the screw's maximum torque, the motor assembly stalls, the rotor cannot rotate, and the increased drilling fluid pressure punctures the stator rubber. At this point, increasing the torque of the rotary table or top drive will cause the stator to rotate relative to the rotor, but the torque still cannot be applied to the drill bit. Drill bit jamming easily leads to stuck pipe accidents, causing downhole complications, and may even require cutting the drill string for sidetracking, resulting in significant losses.

[0003] Currently, with the continuous development of drilling technology, screw motor clutches have emerged in existing technologies, enabling the switching between two transmission routes: screw motor driving the drill bit and rotary table driving the drill bit. When the rotor jams, the rotary table continues to rotate the drill string, which in turn rotates the stator, causing the stator's speed relative to the rotor to exceed a certain value. This activates the clutch through centrifugal force and changes in the relative rotation direction. At this point, the surface torque is transmitted to the drill bit through the stator, clutch mechanism, and rotor, releasing the drill bit from jamming. However, existing screw motor clutches can only be passively activated after a stuck drill bit occurs, releasing the jamming through rotary table torque; they cannot be actively activated as needed. Furthermore, existing screw motor clutches cannot switch to direct rotary table drive of the drill bit before drilling into formations prone to stuck drill bits or formations with high torque, thus failing to achieve the technical effect of preventing stuck drill bits. Summary of the Invention

[0004] To address the technical problems described above, this invention aims to propose a drill bit drive active clutch with a helical locking function. This drill bit drive active clutch can actively switch between two transmission modes—screw motor driving the drill bit and rotary table driving the drill bit—through ground operation as needed, thereby preventing excessive drilling torque from causing stuck drill bit and enabling the release of stuck drill bit after the stuck drill bit is engaged.

[0005] Therefore, according to the present invention, a drill bit transmission active clutch with a helical locking function is provided, comprising: a motor assembly; a clutch assembly connected to the lower end of the motor assembly, the clutch assembly comprising: a housing, a first reverse helix provided on the inner wall of the housing; a sliding toothed jaw disposed within the housing, a second reverse helix provided on the outer wall of the sliding toothed jaw, the second reverse helix being adaptable to the first reverse helix, and the sliding toothed jaw being able to move axially relative to the housing by rotating the sliding toothed jaw; a drill bit connecting shaft for connecting a drill bit, the drill bit connecting shaft being connected to the lower end of the sliding toothed jaw and forming a circumferential fixation with the sliding toothed jaw; and a fixing toothed jaw fitted on the outer wall of the drill bit connecting shaft, the fixing toothed jaw forming a circumferential fixed connection with the housing; wherein, in a first state In the first state, the sliding toothed groove is circumferentially fixedly connected to the motor assembly and disengaged from the fixed toothed groove. The motor assembly can drive the sliding toothed groove to rotate, which in turn drives the drill bit to rotate via the drill bit connecting shaft. The second reverse helix is ​​located at the upper end of the first reverse helix and forms an axial downward lock on the sliding toothed groove. In the second state, the sliding toothed groove moves downward and disengages from the motor assembly, and is adapted to engage with the fixed toothed groove. The drill rod is rotated by the rotary table set at the wellhead, which can drive the housing to rotate, and sequentially drive the drill bit to rotate via the fixed toothed groove, the sliding toothed groove, and the drill bit connecting shaft. The second reverse helix is ​​located at the lower end of the first reverse helix and forms an axial upward lock on the sliding toothed groove. The first state and the second state can be switched between each other.

[0006] In one embodiment, the clutch assembly further includes a hollow rotor connecting shaft, the upper end of which is connected to the motor assembly, and the upper end of the sliding jaw extends into the interior of the rotor connecting shaft. In a first state, the sliding jaw and the rotor connecting shaft are circumferentially fixedly connected, and the motor assembly can drive the rotor connecting shaft to rotate under the action of drilling fluid, thereby driving the sliding jaw to rotate. In a second state, the sliding jaw moves downward relative to the rotor connecting shaft and can rotate relative to the rotor connecting shaft, thereby disengaging from the motor assembly.

[0007] In one embodiment, an elastic element is also fitted onto the sliding toothed jaw. The outer wall of the sliding toothed jaw is provided with a step with the end face facing upward. The two ends of the elastic element abut against the rotor connecting shaft and the step, respectively. In the second state, the elastic element can drive the sliding toothed jaw downward relative to the rotor connecting shaft.

[0008] In one embodiment, a pressure-transmitting hole is provided on the side wall of the housing, and a radial space is formed between the housing and the sliding toothed groove. The elastic element is arranged in the radial space, and the radial space is connected to the wellbore annulus through the pressure-transmitting hole.

[0009] In one embodiment, a first torque transmission engagement surface is provided on the outer wall of the sliding toothed jaw, and a second torque transmission engagement surface is provided on the inner wall of the rotor connecting shaft. In a first state, the first torque transmission engagement surface and the second torque transmission engagement surface are adapted to engage. In a second state, the first torque transmission engagement surface and the second torque transmission engagement surface are disengaged.

[0010] In one embodiment, a third torque transmission engagement surface is provided on the lower inner wall of the sliding toothed jaw, and a fourth torque transmission engagement surface is provided on the outer wall of the drill bit connecting shaft. The third torque transmission engagement surface and the fourth torque transmission engagement surface are adapted to engage, thereby forming a circumferential fixed connection between the drill bit connecting shaft and the sliding toothed jaw.

[0011] In one embodiment, the lower end of the sliding toothed jaw is provided with a first toothed jaw portion, and the upper end of the fixed toothed jaw is provided with a second toothed jaw portion. In a first state, the first toothed jaw portion is disengaged from the second toothed jaw portion, and in a second state, the first toothed jaw portion and the second toothed jaw portion are adapted to engage, thereby enabling the sliding toothed jaw to form a circumferential fixed connection with the fixed toothed jaw.

[0012] In one embodiment, the outer peripheral surface of the fixing toothed jaw is provided with an external spline, and the inner wall of the housing is provided with an internal spline. The external spline can be adapted to the internal spline, thereby forming a circumferential fixed connection between the fixing toothed jaw and the housing.

[0013] In one embodiment, a positioning element is provided at the lower end of the fixed toothed jaw, which can axially limit the fixed toothed jaw.

[0014] In one embodiment, a drill bit connector for connecting a drill bit is provided at the lower end of the drill bit connecting shaft. The drill bit connector is rotatably connected to the housing via a transmission assembly, which includes a transmission shaft and a transmission bearing assembly.

[0015] In one embodiment, the rotor connecting shaft is rotatably connected to the housing via a bearing assembly, and the rotor connecting shaft is rotatably sealed to the housing via an annular seal.

[0016] In one embodiment, the motor assembly includes a motor housing, a stator cavity formed on the inner wall of the motor housing, and a rotor disposed within the motor housing. The rotor connecting shaft is connected to the rotor via a universal joint, and the rotor can rotate under the action of drilling fluid, thereby driving the rotor connecting shaft to rotate.

[0017] Compared with the prior art, the advantages of this application are:

[0018] The active clutch for drill string transmission with helical locking function according to the present invention can actively switch between two transmission modes: the motor assembly driving the drill bit and the rotary table driving the drill bit, according to the actual working conditions. This achieves the functions of preventing excessive drilling torque from causing stuck drill bit and releasing the drill bit after it has stuck. The active clutch for drill string transmission drives the sliding toothed sill to move by the change between the spring force and the drilling fluid pressure, changing the engagement state of multiple sets of torque transmission structures. This allows the drill bit to be driven by the motor assembly during normal drilling, and the drill bit to be driven by the rotary table to drive the drill pipe when high torque is required. This is very beneficial to drilling operations and improves drilling efficiency. The reverse helical structure formed by the first reverse helix on the inner wall of the housing and the second reverse helix on the outer wall of the sliding toothed sill can lock the action of the active clutch for drill string transmission. The clutch is engaged by the combined operation of "stopping the pump, increasing drilling pressure, and rotating the drill string", and disengaged by "lifting the bottom of the well and using a large displacement in non-use situations". This effectively prevents the active clutch for drill string transmission from being misoperated. During operation, the operating status of the drill string drive clutch is determined by factors such as fluid drainage within the drill pipe and torque changes. This allows for proactive control of the clutch's status and adjustment of the transmission path as needed. Furthermore, the clutch can be engaged and disengaged downhole via surface operation, unaffected by changes in drilling parameters. Before drilling into formations prone to sticking or those with high torque, the system can switch to direct rotary table drive of the drill bit, preventing sticking, reducing costs, and improving efficiency. The rotor of the motor assembly rotates both before and after the drill string drive clutch engagement to maintain unobstructed flow within the drill string, without affecting drilling fluid circulation. A high-torque transmission structure is housed in the casing, enabling the transmission of significant torque while keeping the rotor unaffected by torque. The drill string drive clutch can be integrated as a module into existing screw motors, with clutch engagement controlled via conventional drilling maneuvers, eliminating the need to modify the screw motor structure or surface equipment. Attached Figure Description

[0019] The present invention will now be described with reference to the accompanying drawings.

[0020] Figure 1 The structure of a drill drive active clutch with a helical locking function according to the present invention is shown.

[0021] Figure 2 Showing Figure 1 The structure of the rotor connecting shaft in the active clutch of the drill bit transmission shown.

[0022] Figure 3 Showing Figure 1 The structure of the sliding toothed jaw in the active clutch of the drill bit transmission is shown.

[0023] Figure 4 Showing Figure 1 The structure of the fixed toothed jaw in the active clutch of the drill bit transmission shown.

[0024] Figure 5 Showing Figure 1 The structure of the housing in the active clutch of the drill bit transmission shown.

[0025] Figure 6 Showing Figure 1 The structure of the drill bit connecting shaft in the active clutch of the drill bit transmission is shown.

[0026] Figure 7 and Figure 8 The process of helical unlocking of the active clutch of the drill bit drive is shown.

[0027] Figure 9 This shows the engagement status of the drill string drive clutch.

[0028] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0029] The invention will now be described with reference to the accompanying drawings.

[0030] Figure 1 The structure of a drill bit drive active clutch 100 with a helical locking function according to the present invention is shown. Figure 1 As shown, the drill string drive active clutch 100 includes a motor assembly and a clutch assembly connected to the lower end of the motor assembly, as well as a transmission assembly 10 connected to the lower end of the clutch assembly. The transmission assembly 10 is used to connect the drill bit. The drill string drive active clutch 100 is configured to control the pressure inside the drill pipe by controlling the pumping displacement as needed, thereby actively switching between two transmission modes: the motor assembly driving the drill bit and the rotary table driving the drill bit. This achieves the functions of preventing excessive drilling torque from causing stuck drill bit and releasing the stuck drill bit after it has stuck. Specifically, when the clutch assembly is in the disengaged state, the drill string drive active clutch 100 drives the drill bit to drill through the motor assembly. At this time, the drill string drive active clutch 100 is in the first state. When the clutch assembly is in the engaged state, the drill string drive active clutch 100 drives the drill bit to drill through the rotary table or top drive. At this time, the drill string drive active clutch 100 is in the second state.

[0031] like Figure 1 As shown, the motor assembly includes a motor housing 11, a stator cavity 111 formed on the inner wall of the motor housing 11, and a rotor 112 disposed inside the motor housing 11. The rotor 112 can rotate relative to the stator cavity 111 under the action of drilling fluid.

[0032] According to the present invention, such as Figure 1As shown, the drill bit drive active clutch 100 includes a hollow rotor connecting shaft 1, a housing 3, a sliding toothed jaw 4 disposed within the housing 3, a drill bit connecting shaft 6 for connecting the drill bit, and a fixed toothed jaw 7 fitted onto the drill bit connecting shaft 6. The drill bit connecting shaft 6 is connected to the lower end of the sliding toothed jaw, and the drill bit connecting shaft 6 and the sliding toothed jaw 4 are circumferentially fixedly connected. The fixed toothed jaw 7 is circumferentially fixedly connected to the housing 3. The housing 3 is cylindrical in shape and is used to maintain the relative positions of the various parts and allow them to move along a designed trajectory. When the rotary table drives the drill bit (in the second state), the drill rod torque can be transmitted to the fixed toothed jaw 7 through the housing 3.

[0033] In one embodiment, the upper end of the housing 3 is fixedly connected to the motor housing 11 via a threaded connection. The upper end of the rotor connecting shaft 1 is connected to the rotor 112 via a universal joint 113. For example, the upper end of the rotor connecting shaft 1 is fixedly connected to the universal joint 113 via a threaded connection.

[0034] like Figure 2 As shown, the rotor connecting shaft 1 is constructed as a hollow tubular structure, and an annular protrusion extending radially outward is provided on the outer wall of the upper end of the rotor connecting shaft 1. A first annular seal 101 is provided on the outer wall of the rotor connecting shaft 1 near the middle. The upper part of the housing 3 is inserted into the motor housing 11. The rotor connecting shaft 1 is inserted into the housing 3, and a bearing assembly 2 is provided between the lower end face of the annular protrusion and the upper end face of the housing 3. The bearing assembly 2 is used to withstand the axial and radial forces of the rotor connecting shaft 1, thereby allowing the rotor connecting shaft 1 to rotate relative to the housing 3. In addition, the first annular seal 101 is located between the contact surfaces of the rotor connecting shaft 1 and the inner wall of the housing 3, which can effectively ensure the seal between the rotor connecting shaft 1 and the housing 3.

[0035] According to the present invention, Figure 3 The structure of the sliding toothed jaw 4 is shown. (Example) Figure 3 As shown, the sliding jaw 4 has an axially extending flow channel for liquid flow. The sliding jaw 4 is constructed comprising a cylindrical first part and a second part connected to the lower end of the first part, the diameter of the first part being smaller than the diameter of the second part. Thus, an upward-facing step is formed at the connection between the first and second parts. The upper portion of the sliding jaw 4 extends into the interior of the rotor connecting shaft 1, and the sliding jaw 4 is capable of axial movement along the rotor connecting shaft 1. A second annular seal 401 is provided on the outer wall of the first part near its upper end. The second annular seal 401 is located between the contact surfaces of the sliding jaw 4 and the inner wall of the rotor connecting shaft 1, effectively ensuring a seal between the sliding jaw 4 and the rotor connecting shaft 1.

[0036] like Figure 3As shown, a first torque transmission engagement surface 402 is provided on the outer wall surface of the first part of the sliding toothed jaw 4. The first torque transmission engagement surface 402 is located at a certain distance from the upper end face of the sliding toothed jaw 4, thus leaving a cylindrical portion at the upper end of the first torque transmission engagement surface 402. Simultaneously, a second torque transmission engagement surface 102 is provided on the inner wall of the rotor connecting shaft 1, located near the lower end face of the inner wall of the rotor connecting shaft 1. The first torque transmission engagement surface 402 and the second torque transmission engagement surface 102 are configured to form a compatible torque transmission structure, such as a spline, hexagonal, or toothed jaw structure. The upper end of the sliding toothed jaw 4 extends into the interior of the rotor connecting shaft 1, and the sliding toothed jaw 4 can move axially along the rotor connecting shaft 1, thereby achieving the adaptation and separation between the first torque transmission engagement surface 402 and the second torque transmission engagement surface 102. In the first state, the first torque transmission engagement surface 402 and the second torque transmission engagement surface 102 are adapted and engaged, so that the sliding toothed jaw 4 and the rotor connecting shaft 1 are circumferentially fixed. In the second state, the sliding tooth 4 moves downward relative to the rotor connecting shaft 1 so that the first torque transmission engagement surface 402 disengages from the second torque transmission engagement surface 102, thereby enabling the sliding tooth 4 to rotate relative to the rotor connecting shaft 1.

[0037] According to the present invention, a second reverse spiral 404 is provided on the outer wall of the second part of the sliding toothed jaw 4, and the second reverse spiral 404 is located near the lower end of the second part. Meanwhile, a first reverse spiral 301 is provided on the inner wall of the housing 3 (see...). Figure 5 The first reverse spiral 301 can be adapted to the second reverse spiral 404, and can be moved axially relative to the housing 3 by rotating the sliding tooth 4.

[0038] According to the present invention, an elastic element 5 is further sleeved on the sliding toothed jaw 4, with its two ends abutting against the lower end face of the rotor connecting shaft 1 and the step on the outer wall of the sliding toothed jaw 4, respectively. In one embodiment, the elastic element 5 may be a compression spring. In the second state, the elastic element 5 can generate a spring force to push the sliding toothed jaw 4 downward relative to the rotor connecting shaft 1.

[0039] In this embodiment, a radial space is formed between the housing 3 and the sliding toothed jaw 4, and the elastic element 5 is arranged within the radial space. A pressure-transmitting hole 303 (see...) is provided on the side wall of the housing 3 corresponding to the radial space. Figure 5 The radial space is connected to the wellbore annulus through the pressure transmission hole 303.

[0040] In one embodiment, a third annular seal 403 is also provided on the outer wall of the second part of the sliding jaw 4, and the third annular seal 403 is disposed in the outer wall region near the step. The third annular seal 403 is located between the contact surfaces of the sliding jaw 4 and the housing 3, thereby forming a seal between the outer wall surface of the second part of the sliding jaw 4 and the inner wall of the housing 3. This allows the pressure on the upper side of the sliding jaw 4 to communicate with the outside of the drill pipe through the pressure transmission hole 303, while the lower end bears the internal pressure of the drill pipe. The pressure difference between the upper and lower sides of the sliding jaw 4 is related to the drilling fluid discharge rate; the higher the discharge rate, the greater the pressure difference. The spring force of the elastic element 5 balances the pressure difference generated by the normal drilling discharge rate, which prevents the sliding jaw 4 from separating from the fixed jaw 7 under normal drilling conditions.

[0041] Figure 4 The structure of the fixed toothed jaw 7 is shown. (Example) Figure 4 As shown, the fixing tooth holder 7 is cylindrical in shape, and its outer peripheral surface is provided with an external spline 702. Meanwhile, an internal spline 302 is provided on the inner wall surface of the housing 3 (see...). Figure 5 The internal spline 302 is located near the lower end of the housing 3. The fixing toothed bracket 7 is located inside the housing 3 and is installed by adapting the external spline 702 to the internal spline 302, thereby forming a circumferential fixed connection between the fixing toothed bracket 7 and the housing 3.

[0042] According to the present invention, such as Figure 4 As shown, a second toothed portion 701 is provided at the upper end of the fixed toothed portion 7. Meanwhile, a first toothed portion 405 is provided at the lower end of the sliding toothed portion 4 (see...). Figure 3 In the first state, the first toothed jaw portion 405 is disengaged from the second toothed jaw portion 701. In the second state, the sliding toothed jaw 4 moves downward relative to the housing 3, allowing the first toothed jaw portion 405 to engage with the second toothed jaw portion 701, thereby enabling the sliding toothed jaw 4 to form a circumferential fixed connection with the fixed toothed jaw 7. Furthermore, the drill bit connecting shaft 6 passes through the fixed toothed jaw 7 and is adapted to connect with the sliding toothed jaw 4, allowing the fixed toothed jaw 7 to rotate relative to the drill bit connecting shaft 6.

[0043] In one embodiment, a positioning element 8 is provided at the lower end of the fixed toothed jaw 7. Preferably, the positioning element 8 can be a positioning spring. The positioning element 8 can axially limit the fixed toothed jaw 7 to hold it in a certain position and prevent circumferential movement of the fixed toothed jaw 7. At the same time, the positioning element 8 can compensate for axial assembly errors.

[0044] Figure 6 The structure of drill bit connecting shaft 6 is shown. (Example) Figure 6As shown, the drill bit connecting shaft 6 is constructed in a cylindrical shape, and a fourth torque transmission engagement surface 601 is provided on the outer wall of the drill bit connecting shaft 6. The fourth torque transmission engagement surface 601 is configured to extend axially inward from the upper end face of the drill bit connecting shaft 6. Meanwhile, a third torque transmission engagement surface 406 is also provided on the lower inner wall of the sliding jaw 4 (see...). Figure 1 The third torque transmission mating surface 406 and the fourth torque transmission mating surface 601 are configured to form a compatible torque transmission structure. For example, it can be a spline, hexagonal, or toothed structure. This allows the sliding toothed surface 4 to form a circumferential fixed connection with the drill bit connecting shaft 6.

[0045] During operation, the upper end of the sliding toothed jaw 4 is slidably connected to the rotor connecting shaft 1 via an upper torque transmission structure formed by the first torque transmission engagement surface 402 and the second torque transmission engagement surface 102. The lower end of the sliding toothed jaw 4 is slidably connected to the fixed toothed jaw 7 via a lower torque transmission structure formed by the third torque transmission engagement surface 406 and the fourth torque transmission engagement surface 601. The upper torque transmission structure and the lower torque transmission structure can be switched by the axial movement of the sliding toothed jaw 4.

[0046] According to the present invention, such as Figure 1 As shown, a drill bit connector 110 is provided at the lower end of the drill bit connecting shaft 6. The drill bit connector 110 is used to connect a drill bit or other output device. The drill bit connector 110 is rotatably connected to the housing 3 through the transmission assembly 10. The transmission assembly 10 includes a transmission shaft and a transmission bearing assembly. In one embodiment, the transmission shaft is constructed as a hollow shaft, including a first shaft body and a second shaft body fixedly connected to the first shaft body. An outer limiting step and an inner limiting step are formed at the connection between the first shaft body and the second shaft body, with the end face of the outer limiting step facing upward and the end face of the inner limiting step facing downward. The outer wall of the first shaft body is provided with an external thread, which is fixedly connected to the lower inner wall of the housing 3 by a threaded connection, and the end face of the outer limiting step contacts the lower end face of the housing 3. The outer wall of the drill bit connector 110 is provided with an upward-facing mounting step, and the upper end of the drill bit connector 110 is fixedly connected to the drill bit connecting shaft 6 by a thread. The transmission bearing assembly is installed between the transmission shaft and the drill bit connector 110, with its upper and lower ends abutting against the inner limiting step and the mounting step, respectively. This allows the drill bit connector 110 to be rotatably connected to the housing 3 via the transmission assembly 10.

[0047] The working process of the active clutch 100 for drill bit transmission with helical locking function according to the present invention is briefly described below. Figure 1 The structure is shown with the drill bit drive active clutch 100 in the disengaged state. It is assumed that the initial state of the drill bit drive active clutch 100 is the disengaged state (first state). Of course, it can be understood that the initial state of the drill bit drive active clutch 100 can be made to be the engaged state by modifying the design.

[0048] like Figure 1 As shown, in the initial state, the drill bit drive active clutch 100 is in the first state. During drilling, the first torque transmission engagement surface 402 of the sliding tooth sill 4 is adapted to engage with the second torque transmission engagement surface 102 of the rotor connecting shaft 1, while the lower torque transmission structure of the sliding tooth sill 4 is separated from the fixed tooth sill 7. The rotor 112 of the motor assembly rotates under drilling fluid pressure and drives the rotor connecting shaft 1 to rotate via the universal joint 113. The rotor connecting shaft 1 drives the sliding tooth sill 4 to rotate via the upper torque transmission structure formed by the first torque transmission engagement surface 402 and the second torque transmission engagement surface 102, causing the sliding tooth sill 4 to drive the drill bit connecting shaft 6 to rotate via the lower torque transmission structure formed by the third torque transmission engagement surface 406 and the fourth torque transmission engagement surface 601, thereby driving the drill bit joint 110 to rotate, thus transmitting the torque of the rotor 112 to the drill bit. At this time, the second reverse spiral 404 on the outer wall of the sliding toothed jaw 4 is located at the upper end of the first reverse spiral 301 on the inner wall of the housing 3, thereby forming an axially downward locking constraint on the sliding toothed jaw 4, preventing the sliding toothed jaw from moving downward and thus preventing the sliding toothed jaw 4 from engaging with the fixed toothed jaw 7. Thus, the motor assembly drives the drill bit to drill.

[0049] During drilling operations, when encountering high-torque formations or when the drill bit becomes stuck, the drive clutch 100 is activated. Specifically, the pumping of mud into the drill string is stopped, and a lower drilling pressure is applied to the drill bit to prevent it from rotating during activation. At this time, the drill bit is stationary, and the sliding jaw 4 is restricted from rotating via the drill bit connecting shaft 6. The drill string is rotated forward by the rotary table or top drive, which in turn drives the housing 3 to rotate forward. Under the action of the second reverse helix 404 and the first reverse helix 301, the sliding jaw 4 moves downward. This process continues until the second reverse helix 404 disengages from the first reverse helix 301, thus completing the helix unlocking. Figure 7 and Figure 8The process of unlocking the active clutch 100 of the drill bit drive is shown. After the second reverse screw 404 disengages from the first reverse screw 301, the sliding jaw 4 continues to move downward under the action of the elastic element 5, thereby engaging the first jaw portion 405 at the lower end of the sliding jaw 4 with the second jaw portion 701 of the 7. At the same time, the upper torque transmission structure of the sliding jaw 4 separates from the rotor connecting shaft 1. At this time, the drill rod torque is transmitted through the housing 3 to the fixed jaw 7, then to the sliding jaw 4, then to the drill bit connecting shaft 6, and finally to the drill bit. When the drill bit is stationary and the housing 3 is rotating, the stator cavity 111 and the rotor 112 in the motor assembly rotate in opposite directions, and the motor assembly generates a suction action. By observing whether liquid is discharged from the drill rod and the amount of liquid discharged, it can be determined whether the active clutch 100 of the drill bit drive is activated and the completion of the action. When the sliding jaw 4 engages with the fixed jaw 7, the drill rod torque suddenly increases. The change in torque is used to determine whether the active clutch 100 of the drill bit drive is engaged. Figure 9 The engagement state of the drill bit drive clutch 100 is shown. At this time, the second reverse spiral 404 on the outer wall of the sliding toothed jaw 4 is at the lower end of the first reverse spiral 301 on the inner wall of the housing 3, which provides an axially upward locking constraint for the sliding toothed jaw 4. Simultaneously, under the elastic force of the elastic element 5, separation between the sliding toothed jaw 4 and the fixed toothed jaw 7 is prevented under normal drilling conditions. Thus, rotary table-driven drill bit drilling is achieved.

[0050] When it is necessary to disengage the drill string drive clutch 100 and switch to motor assembly driving the drill bit for drilling, the drill string is lifted off the bottom of the well, and the drilling fluid discharge rate is increased to 150%-200% of the normal discharge rate. As the discharge rate increases, the pressure difference acting on the upper and lower sides of the sliding jaw 4 increases until it pushes the sliding jaw 4 upward and compresses the elastic element 5, thereby causing the first torque transmission engagement surface 402 at the upper end of the sliding jaw 4 to re-adapt and engage with the second torque transmission engagement surface 102 of the rotor connecting shaft 1. This allows the sliding jaw 4 to rotate via the rotor connecting shaft 1, and under the action of the second reverse helix 404 and the first reverse helix 301, the sliding jaw 4 continues to move upward. This continues until the second reverse helix 404 disengages from the first reverse helix 301, completing the axial downward locking of the sliding jaw 4. Thus, the drill string drive clutch 100 switches to the disengaged state. The discharge rate is reduced to the normal drilling discharge rate, and the drill string is lowered for normal drilling. At this time, the drill string drive clutch 100 switches to motor assembly driving the drill bit for drilling.

[0051] The active clutch 100 for drill bit transmission with helical locking function according to the present invention can actively switch between two transmission modes: the motor assembly driving the drill bit and the rotary table driving the drill bit, according to the actual working conditions. This achieves the functions of preventing excessive drilling torque from causing stuck drill bit and releasing the stuck drill bit after it has become stuck. The active clutch 100 for drill bit transmission drives the sliding toothed sill to move by the change between the spring force and the drilling fluid pressure, changing the engagement state of multiple sets of torque transmission structures. This allows the drill bit to be driven by the motor assembly during normal drilling, and the drill bit to be driven by the rotary table to drive the drill pipe when high torque is required. This is very beneficial to drilling operations and improves drilling efficiency. The reverse helical structure formed by the first reverse helix 301 on the inner wall of the housing 3 and the second reverse helix 404 on the outer wall of the sliding toothed sill 4 can lock the operation of the active clutch 100 for drill bit transmission. The clutch is engaged by the combined operation of "stopping the pump, increasing drilling pressure, and rotating the drill string", and disengaged by "lifting the bottom of the well and using a large displacement in non-use situations". This effectively prevents the active clutch 100 for drill bit transmission from being misoperated. During operation, the operating status of the drill string drive active clutch 100 is determined by factors such as fluid drainage within the drill pipe and torque changes. This allows for proactive control of the clutch's state and adjustment of the transmission route as needed. Furthermore, the clutch can be engaged and disengaged downhole via surface operation, unaffected by changes in drilling parameters. Before drilling into formations prone to sticking or with high torque, the clutch can be switched to rotary table direct drive of the drill bit, preventing sticking, reducing costs, and improving efficiency. Before and after engagement of the drill string drive active clutch 100, the rotor 112 of the motor assembly can rotate to maintain unobstructed flow within the drill string, without affecting drilling fluid circulation. A high-torque transmission structure is located on the housing 3, capable of transmitting significant torque while keeping the rotor 112 free from torque. The drill string drive active clutch 100 can be integrated as a module into existing screw motors, with clutch engagement controlled by conventional drilling operations, without requiring modifications to the screw motor structure or surface equipment.

[0052] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A drill bit drive active clutch with helical locking function, including: Motor assembly; A clutch assembly connected to the lower end of the motor assembly, the clutch assembly comprising: The housing (3) has a first reverse spiral (301) on its inner wall. A sliding toothed groove (4) is provided inside the housing. A second reverse spiral (404) is provided on the outer wall of the sliding toothed groove. The second reverse spiral can be adapted to the first reverse spiral. By rotating the sliding toothed groove, it can be made to move axially relative to the housing. A drill bit connecting shaft (6) for connecting the drill bit, the drill bit connecting shaft being connected to the lower end of the sliding tooth groove and being circumferentially fixed to the sliding tooth groove; and A fixing toothed groove (7) is fitted on the outer wall of the drill bit connecting shaft, and the fixing toothed groove is circumferentially fixed to the housing; In the first state, the sliding toothed jaw is circumferentially fixedly connected to the motor assembly, while disengaging from the fixed toothed jaw. The motor assembly can drive the sliding toothed jaw to rotate, thereby driving the drill bit to rotate via the drill bit connecting shaft. The second reverse helix is ​​located above the first reverse helix, thus locking the sliding toothed jaw axially downward. In the second state, the sliding toothed groove descends and disengages from the motor assembly, then engages with the fixed toothed groove. Rotating the drill pipe via the rotary table at the wellhead drives the housing to rotate, which in turn drives the drill bit to rotate via the fixed toothed groove, the sliding toothed groove, and the drill bit connecting shaft. The second reverse helix, positioned below the first reverse helix, provides an axial upward lock to the sliding toothed groove. The first state and the second state can be switched between each other.

2. The drill bit transmission drive clutch according to claim 1, characterized in that, The clutch assembly also includes a hollow rotor connecting shaft (1), the upper end of which is connected to the motor assembly, and the upper end of the sliding tooth extends into the interior of the rotor connecting shaft. In the first state, the sliding toothed jaw is circumferentially fixedly connected to the rotor connecting shaft, and the motor assembly can drive the rotor connecting shaft to rotate under the action of drilling fluid, thereby driving the sliding toothed jaw to rotate. In the second state, the sliding toothed jaw moves downward relative to the rotor connecting shaft and can rotate relative to the rotor connecting shaft, thereby disengaging from the motor assembly.

3. The drill bit transmission active clutch according to claim 2, characterized in that, An elastic element is also fitted onto the sliding toothed jaw, and the outer wall of the sliding toothed jaw has a step with the end face facing upwards. The two ends of the elastic element abut against the rotor connecting shaft and the step, respectively. In the second state, the elastic element can drive the sliding tooth to move downward relative to the rotor connecting shaft.

4. The drill bit transmission active clutch according to claim 3, characterized in that, The side wall of the housing is provided with a pressure transmission hole (303), and a radial space is formed between the housing and the sliding toothed groove. The elastic element is arranged in the radial space, and the radial space is connected to the wellbore annulus through the pressure transmission hole.

5. The drill bit transmission drive clutch according to claim 2, characterized in that, A first torque transmission engagement surface (402) is provided on the outer wall of the sliding toothed groove, and a second torque transmission engagement surface (102) is provided on the inner wall of the rotor connecting shaft. In the first state, the first torque transmission mating surface and the second torque transmission mating surface are adapted and engaged. In the second state, the first torque transmission mating surface is disengaged from the second torque transmission mating surface.

6. The drill bit transmission active clutch according to claim 5, characterized in that, A third torque transmission engagement surface (406) is provided on the inner wall of the lower end of the sliding toothed jaw, and a fourth torque transmission engagement surface (601) is provided on the outer wall of the drill bit connecting shaft. The third torque transmission engagement surface and the fourth torque transmission engagement surface are adapted to engage, thereby forming a circumferential fixed connection between the drill bit connecting shaft and the sliding toothed jaw.

7. The drill bit drive active clutch according to claim 5 or 6, characterized in that, The lower end of the sliding toothed jaw is provided with a first toothed jaw portion (405), and the upper end of the fixed toothed jaw is provided with a second toothed jaw portion (701). In the first state, the first toothed portion is detached from the second toothed portion. In the second state, the first toothed portion and the second toothed portion are adapted to engage, thereby enabling the sliding toothed portion to form a circumferential fixed connection with the fixed toothed portion.

8. The drill bit transmission drive clutch according to claim 1, characterized in that, The outer peripheral surface of the fixed toothed jaw is provided with an external spline (702), and the inner wall of the housing is provided with an internal spline (302). The external spline can be adapted to the internal spline, thereby forming a circumferential fixed connection between the fixed toothed jaw and the housing.

9. The drill bit transmission drive clutch according to claim 1 or 8, characterized in that, A positioning element (8) is provided at the lower end of the fixed toothed jaw, which can axially limit the fixed toothed jaw.

10. The drill bit transmission drive clutch according to claim 1, characterized in that, A drill bit connector (110) for connecting a drill bit is provided at the lower end of the drill bit connecting shaft. The drill bit connector is rotatably connected to the housing through a transmission assembly (10). The transmission assembly includes a transmission shaft and a transmission bearing assembly.

11. The drill bit transmission drive clutch according to claim 2, characterized in that, The rotor connecting shaft is rotatably connected to the housing via a bearing assembly (2), and the rotor connecting shaft is rotatably sealed to the housing via an annular seal (101).

12. The drill bit transmission drive clutch according to claim 2, characterized in that, The motor assembly includes a motor housing (11), a stator cavity (111) formed on the inner wall of the motor housing, and a rotor (112) disposed within the motor housing. The rotor connecting shaft is connected to the rotor via a universal joint (113). The rotor can rotate under the action of drilling fluid, thereby driving the rotor connecting shaft to rotate.

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