A positive displacement motor with forced circulation and rotation functions

Abstract

The present invention provides a positive displacement motor with forced circulation and rotation functions, which relates to the technical field of positive displacement motors in drilling engineering. It includes an outer assembly, a motor rotor, and a transmission mechanism. An inner channel is provided inside the motor rotor, and a liquid inlet hole communicating with the inner channel is provided at the top. The bottom of the inner channel is communicated with a liquid flow channel on the drill bit or downhole drill tool. The liquid inlet hole is closed by a sliding sleeve, and the sliding sleeve can open the liquid inlet hole. A first limiting groove is formed by the inner concave of the outer wall of the motor rotor, and a resilient limiting block is arranged in the first limiting groove. A second limiting groove is arranged on the inner wall of the sliding sleeve. The sliding sleeve can align the second limiting groove with the resilient limiting block, and part of the resilient limiting block can rebound into the second limiting groove. The sliding sleeve is circumferentially limited on the outer assembly. The solution provided by the present invention can improve the reliability of the positive displacement motor in the application of complex well conditions, and provide necessary technical means for timely and effectively handling downhole complex situations such as stuck pipe during positive displacement drilling.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole positive displacement motors for drilling engineering, and particularly to a downhole positive displacement motor with forced circulation and rotation functions. Background Art

[0002] A downhole positive displacement motor is a positive displacement downhole motor that uses drilling fluid as power to drive the downhole drill string to rotate. After the drilling fluid is pressurized and pumped out by a pump, it flows through a bypass valve into a motor composed of a stator and a rotor. A certain pressure difference is formed at the inlet and outlet of the motor, which pushes the rotor to rotate around the axis of the stator, and transmits the rotational speed and torque to the downhole drill string through a universal joint shaft and a transmission shaft, thereby realizing the drilling operation. Downhole positive displacement motors have become a widely used downhole power tool in the fields of oil and gas exploration drilling (including conventional oil and gas, shale gas, natural gas hydrates, etc.), geothermal drilling, hot dry rock drilling, scientific drilling, etc.

[0003] The downhole positive displacement motor is driven by drilling fluid at the bottom of the hole. As the sealing cavity formed by the stator and the rotor is formed, changes, and disappears, the rotor is forced to make continuous movements in the stator. Applying a downhole positive displacement motor can provide power near the bottom of the well, reduce the wear and damage of the drill string, and improve the drilling efficiency. It is an indispensable tool especially in directional well and horizontal well drilling. However, complex well conditions often occur during the drilling process. When the drill string below the transmission shaft of the downhole positive displacement motor and the bit or drill tool get stuck and cannot rotate, the motor rotor of the downhole positive displacement motor will brake, so that the sealing cavity of the motor of the downhole positive displacement motor cannot change periodically, the drilling fluid flow channel is closed, that is, normal circulation through the bottom of the well cannot be achieved. At the same time, due to the structural limitations of the existing downhole positive displacement motors, it is impossible to rotate the drill string on the ground to strongly rotate the bit or drill tool at the bottom of the well to release the stuck. Summary of the Invention

[0004] The purpose of the present invention is to provide a downhole positive displacement motor with forced circulation and rotation functions to solve the problems existing in the above-mentioned prior art, improve the reliability of the downhole positive displacement motor in the application of complex well conditions, and provide necessary technical means for timely and effectively handling downhole complex conditions such as stuck drill in screw drilling.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] The present invention provides a screw drill with forced circulation and rotation functions, comprising an outer assembly, a transmission mechanism and a motor rotor installed in the outer assembly, a side gap and a motor volume cavity are formed between the motor rotor and the outer assembly, a liquid inlet cavity is formed at the top of the outer assembly, the liquid inlet cavity, the side gap and the motor volume cavity are connected in sequence, an inner channel is arranged inside the motor rotor, a liquid inlet hole connected to the inner channel is arranged at the top, the bottom of the inner channel is connected to a liquid flow channel on a drill bit or a bottom hole drilling tool, the liquid inlet hole is normally closed, the liquid inlet hole is closed by a sliding sleeve, and the sliding sleeve is arranged along the inner channel. The outer assembly can be slidably arranged between the motor rotor and the outer assembly in the length direction, and sliding the sliding sleeve can open the liquid inlet hole. Part of the outer wall of the motor rotor on which the sliding sleeve is sleeved is concave to form a first limiting groove, and a reboundable limiting block is arranged in the first limiting groove. The inner wall of the sliding sleeve is provided with a second limiting groove, and sliding the sliding sleeve can make the second limiting groove align with the reboundable limiting block, and part of the reboundable limiting block can rebound into the second limiting groove, and the other part is located in the first limiting groove. The sliding sleeve is circumferentially limited on the outer assembly.

[0007] Preferably, it further comprises a flow guide ball seat, the flow guide ball seat is located on the sliding sleeve, a flow guide cavity is formed at one end of the flow guide ball seat, and a ball cavity is formed at the other end, the ball cavity and the flow guide cavity are communicated through a central water hole therebetween, the flow guide cavity is openly provided on one side away from the ball cavity, the flow guide ball seat is provided with a side of the flow guide cavity facing the motor rotor, the flow guide cavity is provided with a side water hole, the flow guide ball seat is slidably provided in the liquid inlet cavity along the length direction of the outer assembly, an annular flange is provided on the cavity wall of the liquid inlet cavity, and the outer wall of the top of the flow guide ball seat cooperates with and slides in contact with the annular flange;

[0008] When the guide ball seat is in sliding contact with the annular flange, the upper part of the liquid inlet cavity and the lower part of the liquid inlet cavity can only be connected through the central water hole;

[0009] When the guide ball seat moves toward the motor rotor until it completely slides out of the annular flange, the liquid inlet chamber, the side water eye and the inner channel are connected in sequence, and the sliding sleeve is squeezed by the guide ball seat until the second limit groove is aligned with the rebound limit block.

[0010] Preferably, an elastic support device is provided at one end of the sliding sleeve away from the guide ball seat, and the elastic support device is seated on the inner table surface of the outer assembly, and the elastic support device applies an elastic support force to the sliding sleeve.

[0011] Preferably, it also includes a sphere, which can be thrown into the ball cavity and block the central water eye.

[0012] Preferably, the sliding sleeve is a guiding spline sleeve. Multiple spline bars of the guiding spline sleeve are respectively arranged corresponding to multiple key grooves on the inner wall of the outer assembly. Multiple water grooves are formed on the outer wall of the guiding spline sleeve, and the water grooves penetrate through the guiding spline sleeve along the length direction of the guiding spline sleeve.

[0013] Preferably, the resilient limiting block includes a limiting block and multiple elastic members. Multiple accommodating grooves are arranged on the end face of the limiting block facing the bottom surface of the first limiting groove. One elastic member corresponds to one accommodating groove. In the initial state, the elastic member is compressed in the accommodating groove.

[0014] Preferably, an anti-drop ring is also sleeved and fixed on the outer wall of the motor rotor.

[0015] Preferably, the liquid inlet cavity is used to communicate with the liquid outlet end of a liquid pump.

[0016] Preferably, the transmission mechanism includes a universal shaft assembly, a flow dividing joint and a transmission shaft. The universal shaft assembly is threadedly connected to the lower end of the motor rotor. The flow dividing joint is threadedly connected to the lower end of the universal shaft assembly. The upper end of the transmission shaft is threadedly connected to the lower end of the flow dividing joint. The lower end of the transmission shaft is connected to a drill bit or downhole drilling tools.

[0017] The present invention has achieved the following technical effects compared with the prior art:

[0018] During the drilling process using the positive displacement motor provided by the present invention, if the drill bit or drilling tools below the transmission shaft of the positive displacement motor encounter resistance and jamming and cannot rotate, the motor rotor of the positive displacement motor will be braked and cannot rotate, so that the motor sealing cavity cannot change periodically, and the drilling fluid stops circulating. At this time, the liquid inlet hole of the inner channel is opened by sliding the sliding sleeve, and then the circulation of the drilling fluid is restored, ensuring the smooth flow of the drilling fluid flow channel of the positive displacement motor and realizing the normal bottom circulation of the drilling fluid. In addition, by sliding the sliding sleeve, some of the resilient limiting blocks rebound into the second limiting groove. By forcibly rotating the upper drill string at the wellhead, the rotational speed and torque can be transmitted to the bottom drill bit and drilling tools through the positive displacement motor, and the forced rotation function can be realized. And by rotating the jammed part underground and cooperating with the circulation of the drilling fluid, the phenomenon of releasing the jam can be realized. The positive displacement motor provided by the present invention improves the reliability of the positive displacement motor in the application of complex well conditions through the forced circulation and rotation functions of the drilling fluid, and provides a necessary technical means for timely and effectively handling downhole complex situations such as sticking during positive displacement drilling. Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 Figure 4 is a schematic diagram of the upper structure of the positive displacement motor with forced circulation and rotation functions provided by the present invention under normal working conditions;

[0021] Figure 2 Figure 8 is a schematic diagram of the lower structure of the positive displacement motor with forced circulation and rotation functions provided by the present invention under normal working conditions;

[0022] Figure 3 Figure 12 is a schematic diagram of the upper structure of the positive displacement motor with forced circulation and rotation functions provided by the present invention under the forced rotation state;

[0023] Figure 4 Figure 16 is a schematic diagram of the structure of the diversion ball seat;

[0024] Figure 5 For Figure 4 sectional view;

[0025] Figure 6 Figure 26 is a schematic diagram of the structure of the diversion ball seat;

[0026] Figure 7 For Figure 6 sectional view;

[0027] Figure 8 Figure 36 is a schematic diagram of the structure of the guide spline sleeve;

[0028] Figure 9 For Figure 8 sectional view taken along line A-A in

[0029] Figure 10 For Figure 8 sectional view taken along line B-B in

[0030] Figure 11 For Figure 10 sectional view taken along line C-C in

[0031] Figure 12 Figure 58 is a schematic diagram of the structure of the motor rotor;

[0032] In the figure: 1. bypass valve; 2. guiding outer tube; 3. diversion ball seat; 4. guiding spline sleeve; 5. motor rotor; 6. limit block; 7. elastic member; 8. elastic support device; 9. support seat; 10. anti-falling ring; 11. motor stator; 12. motor assembly; 13. universal shaft assembly; 14. shunt joint; 15. thrust bearing set; 16. transmission shaft; 17. sphere; 21. keyway; 31. central water eye; 32. side water eye; 41. water tank; 42. second limit groove; 43. key bar; 51. liquid inlet hole; 52. first limit groove; 53. inner channel. Detailed implementation manners

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] The purpose of the present invention is to provide a positive displacement motor with forced circulation and rotation functions to solve the problems existing in the above-mentioned prior art, improve the reliability of the positive displacement motor in the application of complex well conditions, and provide necessary technical means for timely and effectively handling downhole complex situations such as sticking during positive displacement motor drilling.

[0035] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0036] The present invention provides a positive displacement motor with forced circulation and rotation functions, as Figures 1 to 12As shown, it includes an outer assembly, a transmission mechanism, and a motor rotor 5 installed inside the outer assembly. The motor rotor 5 is drivingly connected to a drill bit or downhole drilling tools through the transmission mechanism. A side clearance and a motor volume chamber are formed between the motor rotor 5 and the outer assembly. The space at the top inside the outer assembly forms a liquid inlet chamber. The liquid inlet chamber, the side clearance, and the motor volume chamber are connected in sequence. An inner channel 53 is provided inside the motor rotor 5. The inner channel 53 is opened along the axial direction of the motor rotor 5. A liquid inlet hole 51 communicating with the inner channel 53 is provided at the top. A bottom water eye indirectly communicating with the liquid flow channel on the drill bit or downhole drilling tools is provided at the bottom of the inner channel 53. The liquid inlet hole 51 is normally closed and is closed by a sliding sleeve. The sliding sleeve is slidably arranged between the motor rotor 5 and the outer assembly along the length direction of the outer assembly. Sliding the sliding sleeve can open the liquid inlet hole 51. A part of the outer wall of the motor rotor 5 sleeved with the sliding sleeve is recessed to form a first limiting groove 52. A resilient limiting block is provided in the first limiting groove 52. A second limiting groove 42 is provided on the inner wall of the sliding sleeve. Sliding the sliding sleeve can align the second limiting groove 42 with the resilient limiting block, and part of the resilient limiting block can rebound into the second limiting groove 42, and the other part is located in the first limiting groove 52. The sliding sleeve is circumferentially limited on the outer assembly.

[0037] During the drilling process using the positive displacement motor provided by the present invention, if the drill bit or drilling tools below the drive shaft 16 of the positive displacement motor encounter resistance and jamming and cannot rotate, the motor rotor 5 of the positive displacement motor will be braked and unable to rotate, so that the motor sealing chamber cannot change periodically, and the drilling fluid stops circulating. At this time, sliding the sliding sleeve opens the liquid inlet hole 51 of the inner channel 53, thereby restoring the circulation of the drilling fluid, ensuring the smoothness of the drilling fluid flow channel of the positive displacement motor, and realizing the normal bottom-hole circulation of the drilling fluid. In addition, by sliding the sliding sleeve, part of the resilient limiting block rebounds into the second limiting groove 42. By forcibly rotating the upper drill string at the wellhead, the rotational speed and torque can be transmitted to the bottom-hole drill bit and drilling tools through the positive displacement motor, and the forced rotation function can be realized. And by rotating the stuck part underground and cooperating with the circulation of the drilling fluid, the phenomenon of releasing the jam can be realized. The positive displacement motor provided by the present invention improves the reliability of the positive displacement motor in the application of complex well conditions through the forced circulation and rotation functions of the drilling fluid, and provides a necessary technical means for timely and effectively handling downhole complex situations such as stuck drill in screw drilling.

[0038] When the drill bit or drilling tools below the drive shaft 16 of the positive displacement motor encounter resistance and jamming, most of the cases are due to underground crushed stones hindering rotation. Therefore, when using the solution provided by the present invention for forced rotation, the crushed stones can be loosened or crushed, and then the crushed stones can be flushed out through the circulation of the drilling fluid to achieve the purpose of releasing the jam.

[0039] Further, the positive displacement motor with forced circulation and rotation functions further includes a diversion ball seat 3 and a sphere 17. The diversion ball seat 3 is located on the sliding sleeve. One end of the diversion ball seat 3 is provided with a diversion cavity, and the other end is provided with a ball cavity. The ball cavity and the diversion cavity are communicated through a central water eye 31 therebetween. The side of the diversion cavity facing away from the ball cavity is open. The side of the diversion ball seat 3 with the diversion cavity faces the motor rotor 5. The diversion cavity is provided with side water eyes 32. The diversion ball seat 3 is slidably arranged in the liquid inlet cavity along the length direction of the outer assembly. An annular flange is provided on the cavity wall of the liquid inlet cavity. The outer wall of the top of the diversion ball seat 3 is matched with and slidably contacts the annular flange. When the diversion ball seat 3 is in slidable contact with the annular flange, only the upper part and the lower part of the liquid inlet cavity can be conducted through the central water eye 31. When the diversion ball seat 3 moves towards the motor rotor 5 until the diversion ball seat 3 completely slides out of the annular flange, the liquid inlet cavity, the side water eyes 32 and the inner channel 53 are communicated in sequence, and the sliding sleeve is pressed by the diversion ball seat 3 until the second limiting groove 42 is aligned with the resilient limiting block, and the sphere 17 can be thrown into the ball cavity and block the central water eye 31.

[0040] In this embodiment, a specific design is made for how to realize the sliding of the sliding sleeve. The using process is as follows. When the drill is stuck, the operator throws the sphere 17 into the drill string from the wellhead. The sphere 17 falls into the ball cavity and blocks the central water eye 31. Continuously pump drilling fluid into the liquid inlet cavity. As the hydraulic pressure in the liquid inlet cavity increases, the liquid pressure drives the diversion ball seat 3, and the diversion ball seat 3 presses the sliding sleeve to move downward. And when the diversion ball seat 3 moves towards the motor rotor 5 until the diversion ball seat 3 completely slides out of the annular flange, the liquid inlet cavity, the side water eyes 32 and the inner channel 53 are communicated in sequence, and the sliding sleeve is pressed by the diversion ball seat 3 until the second limiting groove 42 is aligned with the resilient limiting block, and the resilient limiting block pops out to realize the circumferential limit of the motor rotor 5 and the outer assembly. Of course, other methods can also be adopted, such as controlling the movement of the sliding sleeve by an intelligent control system, etc.

[0041] Further, the ball cavity is conical to facilitate the guiding of the sphere 17.

[0042] Further, the sphere 17 is preferably a steel ball.

[0043] Further, an elastic support device 8 is arranged at one end of the sliding sleeve facing away from the diversion ball seat 3. The elastic support device 8 is seated on the inner table surface of the outer assembly. The elastic support device 8 applies an elastic support force to the sliding sleeve so that the outer wall of the sliding sleeve can contact the annular flange. And when being pressed, the sliding sleeve can overcome the elastic force of the elastic support device 8 and move towards the bottom of the hole. The elastic support device 8 is a support spring, and the support spring is sleeved outside the motor rotor 5.

[0044] Further, the sliding sleeve is a guiding spline sleeve 4. A plurality of key bars 43 of the guiding spline sleeve 4 are respectively arranged corresponding to a plurality of key grooves 21 on the inner wall of the outer assembly. A plurality of water grooves 41 are formed on the outer wall of the guiding spline sleeve 4, and the water grooves 41 communicate with the gap between the liquid inlet chamber, the motor rotor 5 and the outer assembly.

[0045] Further, the resilient limiting block includes a limiting block 6 and a plurality of elastic members 7. A plurality of accommodating grooves are arranged on the end face of the limiting block 6 facing the bottom surface of the first limiting groove 52. One elastic member 7 corresponds to one accommodating groove. In the initial state, the elastic member 7 is compressed in the accommodating groove.

[0046] Further, an anti-drop ring 10 is also sleeved and fixed on the outer wall of the motor rotor 5.

[0047] Further, the liquid inlet chamber is used to communicate with the liquid outlet end of the liquid pump.

[0048] Further, the transmission mechanism includes a universal shaft assembly 13, a shunt joint 14 and a transmission shaft 16. The universal shaft assembly 13 is threadedly connected to the lower end of the motor rotor 5. The shunt joint 14 is threadedly connected to the lower end of the universal shaft assembly 13. The upper end of the transmission shaft 16 is threadedly connected to the lower end of the shunt joint 14, and the lower end of the transmission shaft 16 is connected to the drill bit or downhole drill tool.

[0049] Further, the outer assembly includes a bypass valve 1, a guiding outer tube 2, a support seat 9 and a motor stator 11. The bypass valve 1, the guiding outer tube 2, the support seat 9 and the motor stator 11 are threadedly connected in sequence. An annular flange is arranged inside the guiding outer tube 2. The upper end of the diversion ball seat 3 is in contact and cooperation with the inner wall of the annular flange. The lower end of the diversion ball seat 3 sits on the upper step surface of the inner wall of the upper end of the guiding spline sleeve 4. The outer wall spline of the guiding spline sleeve 4 cooperates with the key groove 21 on the inner wall of the guiding outer tube 2 under the support of the support spring. The limiting block 6 compresses the elastic member 7 and is pre-installed in the first limiting groove 52 at the upper end of the motor rotor 5. The support spring sits on the step surface of the inner wall of the support seat 9. The anti-drop ring 10 is threadedly connected to the motor rotor 5. The spiral part of the lower end spiral outer wall of the motor rotor 5 meshes with the spiral part of the inner wall of the motor stator 11 to form a motor assembly 12. The universal shaft assembly 13 is threadedly connected to the lower end of the motor stator 11. The shunt joint 14 is threadedly connected to the lower end of the universal shaft assembly 13. The thrust bearing group 15 is axially fixed by upper and lower bushings and cooperates with the inner wall of the motor stator 11 and the outer wall of the transmission shaft 16. The upper end of the transmission shaft 16 is threadedly connected to the lower end of the shunt joint 14, and the lower end of the transmission shaft 16 is connected to the drill bit or downhole drill tool.

[0050] During normal drilling, such as Figure 1As shown, the drilling fluid enters from the bypass valve 1, passes through the central water eye 31 of the diversion ball seat 3, flows out from the side water eye 32, flows through the water tank 41 of the guiding spline sleeve 4 to the lower part of the drill string, and enters the motor volume chamber through the annular gap formed by the support seat 9, the motor stator 11, the motor rotor 5 and the anti-falling ring 10. The motor rotor 5 rotates in the spiral chamber on the inner wall of the motor stator 11. The rotational speed and torque of the motor rotor 5 are transmitted to the transmission shaft 16 through the universal shaft assembly 13 and the flow dividing joint 14, and then transmitted to the drill bit or the downhole drill string. The thrust bearing group 15 transmits the axial and radial loads on the stator housing of the positive displacement motor to the transmission shaft 16, and at the same time realizes the single-rotation function between the transmission shaft 16 and the motor stator 11.

[0051] During drilling, if complex conditions occur in the wellbore and the drill bit or downhole drill string cannot rotate due to sticking, at this time, the transmission shaft 16, the flow divider joint 14, the universal shaft assembly 13, and the motor rotor 5 cannot rotate. At this time, the volume chamber in the motor assembly 12 cannot change along the spiral line, the drilling fluid passage is closed, and normal bottom-hole circulation cannot be carried out. At this time, when the drill string is forced to rotate at the wellhead, when the torque and speed are transmitted to the positive displacement motor, the outer assembly composed of the bypass valve 1, the guide outer tube 2, the guide spline sleeve 4, and the motor stator 11 will rotate, and the torque and speed cannot be transmitted to the inner assembly composed of the motor rotor 5, the universal shaft assembly 13, the flow divider joint 14, and the transmission shaft 16. Therefore, when operating by forcing rotation at the wellhead, the torque and speed cannot be transmitted to the drill bit or downhole drill string. By dropping steel balls into the drill string from the wellhead, when the steel balls reach the diversion ball seat 3 under the action of gravity, the central water eye 31 in the diversion ball seat 3 is closed, the drilling fluid flow path is closed, the drilling fluid pressure on the upper end face of the diversion ball seat 3 increases, and the diversion ball seat 3 and the guide spline sleeve 4 are pushed to compress the support spring and move downward. Since the guide spline sleeve 4 moves downward, the annular gap between the diversion ball seat 3 and the upper end of the guide outer tube 2 is opened, the water tank 41 is closed by the inner wall of the guide outer tube 2, and after the diversion ball seat 3 moves downward, the water eye closed at the upper end of the motor rotor 5 is opened. At this time, the drilling fluid flows in through the side water eye 32 of the diversion ball seat 3, flows into the inner channel 53 through the liquid inlet hole of the motor rotor 5, flows out from the bottom water eye at the lower end of the motor rotor 5, and a small amount of drilling fluid flows into the thrust bearing group 15 through the annular gap between the universal shaft assembly 13 and the motor stator 11 and then flows to the bottom hole, while most of the drilling fluid enters the central water eye of the transmission shaft 16 through the side water eye of the flow divider joint 14 and flows to the bottom hole, realizing normal circulation of the bottom-hole drilling fluid. On the other hand, when the guide spline sleeve 4 moves downward, the second limit groove 42 is aligned with the resilient limit block, and the limit block 6 is pushed out under the elastic force of the elastic member 7 and partially inserted into the second limit groove 42 of the guide spline sleeve 4, forming circumferential and axial limits on the guide spline sleeve 4. At the same time, the speed and torque of the guide spline sleeve 4 can be transmitted to the motor rotor 5 through the limit block 6. By forcing the drill string to rotate at the wellhead, the speed and torque are transmitted to the bypass valve 1 and the guide outer tube 2 of the positive displacement motor. The guide outer tube 2 is engaged with the key bar 43 of the guide spline sleeve 4 through the key groove 21 to transmit the speed and torque to the guide spline sleeve 4, and then through the cooperation of the guide spline sleeve 4 with the limit block 6 and the motor stator 11, the torque and speed are transmitted to the motor rotor 5, and thus transmitted to the drill bit or downhole drill string through the universal shaft assembly 13, the flow divider joint 14, and the transmission shaft 16, realizing strong rotation to release the stuck.

[0052] In the present invention, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A positive displacement motor with forced circulation and rotation functions, characterized in that: It includes an outer assembly, a transmission mechanism, and a motor rotor installed inside the outer assembly. A side clearance and a motor volume chamber are formed between the motor rotor and the outer assembly. The space at the top inside the outer assembly forms a liquid inlet chamber. The liquid inlet chamber, the side clearance, and the motor volume chamber are connected in sequence. An inner channel is provided inside the motor rotor, and a liquid inlet hole communicating with the inner channel is provided at the top. The bottom of the inner channel is connected to a liquid flow channel on the drill bit or downhole drill tool. The liquid inlet hole is normally closed and is closed by a sliding sleeve. The sliding sleeve is slidably arranged between the motor rotor and the outer assembly along the length direction of the outer assembly. Sliding the sliding sleeve can open the liquid inlet hole. A part of the outer wall of the motor rotor sleeved with the sliding sleeve is concave to form a first limiting groove. A resilient limiting block is arranged in the first limiting groove. A second limiting groove is arranged on the inner wall of the sliding sleeve. Sliding the sliding sleeve can align the second limiting groove with the resilient limiting block, and part of the resilient limiting block can rebound into the second limiting groove, and the other part is located in the first limiting groove. The sliding sleeve is circumferentially limited on the outer assembly.

2. The positive displacement motor with forced circulation and rotation functions according to claim 1, characterized in that: It further includes a diversion ball seat. The diversion ball seat is located on the sliding sleeve. One end of the diversion ball seat is provided with a diversion chamber, and the other end is provided with a ball chamber. The ball chamber and the diversion chamber are connected by a central water eye therebetween. The side of the diversion chamber facing away from the ball chamber is open. The side of the diversion ball seat provided with the diversion chamber faces the motor rotor. The diversion chamber is provided with side water eyes. The diversion ball seat is slidably arranged in the liquid inlet chamber along the length direction of the outer assembly. An annular flange is provided on the wall of the liquid inlet chamber. The outer wall at the top of the diversion ball seat is in sliding contact with the annular flange; When the diversion ball seat is in sliding contact with the annular flange, the upper part and the lower part of the liquid inlet chamber can only be conducted through the central water eye; When the diversion ball seat moves towards the motor rotor until the diversion ball seat completely slides out of the annular flange, the liquid inlet chamber, the side water eyes, and the inner channel are connected in sequence, and the sliding sleeve is squeezed by the diversion ball seat until the second limiting groove is aligned with the resilient limiting block.

3. The positive displacement motor with forced circulation and rotation functions according to claim 2, characterized in that: An elastic support device is provided at one end of the sliding sleeve facing away from the diversion ball seat. The elastic support device is located on the inner table surface of the outer assembly, and the elastic support device applies an elastic support force to the sliding sleeve.

4. The positive displacement motor with forced circulation and rotation functions according to claim 2, characterized in that: It further includes a sphere, and the sphere can be thrown into the ball chamber to block the central water eye.

5. The positive displacement motor with forced circulation and rotation functions according to claim 2, characterized in that: The sliding sleeve is a guiding spline sleeve. A plurality of spline bars of the guiding spline sleeve are respectively arranged corresponding to a plurality of key grooves on the inner wall of the outer assembly. A plurality of water grooves are formed on the outer wall of the guiding spline sleeve, and the water grooves penetrate through the guiding spline sleeve along the length direction of the guiding spline sleeve.

6. The positive displacement motor drill with forced circulation and rotation functions according to claim 1, characterized in that: The resilient limiting block includes a limiting block and a plurality of elastic members. A plurality of accommodating grooves are arranged on the end surface of the limiting block facing the bottom surface of the first limiting groove. One elastic member corresponds to one accommodating groove. In the initial state, the elastic member is compressed in the accommodating groove.

7. The positive displacement motor drill with forced circulation and rotation functions according to claim 1, characterized in that: An anti-falling ring is also sleeved and fixed on the outer wall of the motor rotor.

8. The positive displacement motor drill with forced circulation and rotation functions according to claim 1, characterized in that: The liquid inlet cavity is used for communicating with the liquid outlet end of a liquid pump.

9. The positive displacement motor drill with forced circulation and rotation functions according to claim 1, characterized in that: The transmission mechanism includes a universal shaft assembly, a flow dividing joint and a transmission shaft. The universal shaft assembly is threadedly connected to the lower end of the motor rotor. The flow dividing joint is threadedly connected to the lower end of the universal shaft assembly. The upper end of the transmission shaft is threadedly connected to the lower end of the flow dividing joint. The lower end of the transmission shaft is connected to a drill bit or a downhole drill tool.

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