Electrically controlled downhole casing cutting tool

Abstract

This invention discloses an electrically controlled downhole casing cutting tool, belonging to the field of oil and gas well casing cutting technology. Specifically, the tool includes a connection module and a cutting control module. When the cutting control module reaches the cutting position, the ground terminal sends a cutting command to the control unit. The control unit controls an electromagnet to attract the armature, unlocking the cutter body. A motor drives a lead screw to change the position of the cutter body, cutting casings of different diameters, achieving the effect of cutting multiple casings in a single drilling operation. When the cutting position is not reached, the inner and outer cones in the connection module cooperate to spray high-pressure working fluid to clean impurities inside the casing, improving casing lifespan. This invention has a compact structure, high level of intelligence, high cutting efficiency, and can effectively cut casings, reducing the number of tripping operations.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well casing cutting technology, specifically relating to an electrically controlled downhole casing cutting tool. Background Technology

[0002] In the completion and disposal operations throughout the entire life cycle of oil and gas wells, casing cutting is a critical engineering step, facing extremely severe technological challenges and multiple safety risks. Specifically, during the delivery phase of the cutting tool into the wellbore, in order to overcome the complex fluid resistance downhole and the accidental activation that may be caused by pipe wall friction, the work site usually has to rely on temporary filler to physically seal the tool gaps. However, this passive defense method has limited reliability under high temperature and high pressure environments. Once it fails, the cutter blades will open prematurely at an unintended position, inevitably causing mechanical damage to the inner wall of the upper well section of the casing. In addition, during the tubing recovery phase after the cutting process, as the axial force or hydraulic energy applied to the tool is removed, the cutter blades should theoretically retract automatically using spring force. However, due to the obstruction of metal chips generated during cutting or the fatigue of the return mechanism, the cutter head often fails to fully retract into the cutter body. This "semi-open" state can easily induce serious casing jamming accidents when the drill string passes through the coupling or the reduction in diameter. The aforementioned series of complex downhole obstructions and tubing damage risks will not only directly lead to the intervention of remedial measures such as fishing, causing non-productive time to increase exponentially, but will also seriously impact the controllability of the entire operation cycle and the economic benefits of the project. Summary of the Invention

[0003] The purpose of this invention is to provide an electrically controlled downhole casing cutting tool to solve the problems mentioned above. The tool issues a cutting operation command through a ground terminal, and after receiving the command, the control unit controls the motor and electromagnet to extend the cutter body to cut the casing.

[0004] To solve the above problems, the present invention adopts the following technical solution: an electrically controlled downhole casing cutting tool, characterized in that: the electrically controlled downhole casing cutting tool includes a connection module and a cutting control module;

[0005] The connection module includes an upper connector, a mandrel, a cutting shell, a short connector, an outer cone, and an inner cone. The upper end of the upper connector is connected to the drill string, and the lower end of the upper connector is connected to the cutting shell via a thread. The mandrel is connected inside the upper connector via a thread. The short connector is connected to the cutting shell via a thread. The outer cone is connected to the short connector via a thread. The inner cone is connected to the mandrel via a thread. An inner cone nozzle is formed on the surface of the inner cone, and an outer cone nozzle is formed on the surface of the outer cone. The inner cone nozzle and the outer cone nozzle are concentrically fitted. The diameter of the outer cone nozzle is smaller than the diameter of the inner cone nozzle, so that the working fluid is accelerated by the two-stage nozzles to form a high-pressure jet, which directly acts on the inner wall of the casing to achieve the effect of cleaning the inner wall of the casing.

[0006] The cutting control module includes a control unit base, a control unit, a battery pack, a motor, a motor support, a lead screw nut, a lead screw, a push cylinder, an electromagnet, an armature, an armature return spring, a lever, a thrust ball bearing, a tool holder, a support frame, a tool body, a tool body return spring, and a spring seat. The control unit base is mounted on the surface of the spindle. The control unit base is axially positioned by a shaft elastic retaining ring. A wire hole is provided at the lower end of the control unit base for arranging wires to connect the motor and the electromagnet. The control unit includes an MCU, a power management circuit, a motor drive circuit, a wireless communication circuit, a filter circuit, and an electromagnet drive circuit, all integrated on a PCB board. The control unit and the battery pack are bolted to the inside of the control unit base. The motor is connected to the motor support by screws, and the motor support is fixed to the surface of the spindle by screws. The lead screw nut is bolted to the upper surface of the push cylinder. The lead screw and lead screw nut are concentrically fitted. The motor and the lead screw are connected by a coupling. The lead screw is installed in a lead screw guide rail set in the push cylinder. The motor, motor support, lead screw nut, lead screw, and lead screw guide rail are axially evenly distributed in three sets, allowing the push cylinder to be smoothly pushed out. The push cylinder and mandrel are installed concentrically. The electromagnet is installed in an electromagnet groove on the surface of the push cylinder and fixed with screws. The armature return spring is installed in an armature return spring groove on the push cylinder. The armature is threaded into the armature hole at the front end of the lever. The lever is bolted into the lever positioning hole, allowing the lever to rotate around the lever positioning hole. The armature fits into 14 movable positioning holes on the surface of the mandrel. Different movable positioning holes correspond to different extension positions of the cutter body. When the electromagnet is energized, it attracts the armature, allowing the push cylinder to move around the motor. The blade moves axially under the action of the blade extension position. A thrust ball bearing is installed at the lower end of the push cylinder, and the blade holder is installed at the lower end of the thrust ball bearing. The two ends of the support frame are connected to the blade holder hinge and the blade body by bolts. The lower end of the blade body is connected to the cutting shell hinge on the surface of the cutting shell by bolts. The blade body is installed in the blade groove on the surface of the cutting shell. Four sets of blades are evenly distributed around the circumference of the blade body to improve cutting efficiency. The blade return spring is installed in the return spring groove on the lower end of the spring seat and the blade holder. The spring seat is installed concentrically with the spindle, and the spring seat is positioned axially by a short connector.

[0007] As a further technical solution of the present invention, the armature return spring is in a pre-compressed state, so that the armature is engaged in the movable positioning hole, avoiding axial movement of the push cylinder and causing the cutter body to accidentally extend and scratch the well wall.

[0008] As a further technical solution of the present invention, the surface of the blade body is provided with high-strength cylindrical teeth, which extends the service life of the blade body and improves the cutting efficiency.

[0009] As a further technical solution of the present invention, the motor is equipped with an encoder, which enables the control unit to obtain the current number of motor rotations through the encoder, thereby calculating the movement distance of the lead screw and achieving precise control of the armature to engage with the moving positioning hole.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] By sending cutting commands to control the tool through the ground terminal, the tool's intelligence is improved, and multi-stage diameter-changing logic enables the cutting of multiple diameter casings in a single drilling operation, thus improving work efficiency. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the electrically controlled downhole casing cutting tool in an embodiment of the present invention;

[0013] Figure 2 Axonometric drawing of the cut outer shell;

[0014] Figure 3 This is a cross-sectional view of the pusher cylinder;

[0015] Figure 4 Isometric drawing of the lever;

[0016] Figure 5 Axonometric drawing of the tool holder;

[0017] Figure 6 Axonometric drawing of the tool body;

[0018] Figure 7 Axonometric drawing of the inner cone head;

[0019] Figure 8 Axonometric drawing of the external cone head;

[0020] Figure 9 A flowchart of the tool's workflow;

[0021] In the diagram: 1-Upper connector, 2-Mandrel, 201-Moving positioning hole, 3-Cutting shell, 301-Cutting shell hinge, 302-Tool slot, 4-Control unit base, 401-Wire hole, 5-Control unit, 6-Battery pack, 7-Motor, 8-Motor support, 9-Lead screw nut, 10-Lead screw, 11-Push cylinder, 1101-Lead screw guide rail, 1102-Electromagnet groove, 1103-Armature return spring groove, 1104-Pulley 12-Electromagnet, 13-Armature, 14-Armature return spring, 15-Turn lever, 1501-Armature hole, 16-Thrust ball bearing, 17-Tool holder, 1701-Tool holder hinge, 1702-Return spring groove, 18-Support frame, 19-Tool body, 20-Tool body return spring, 21-Spring seat, 22-Short connector, 23-Outer cone, 2301-Outer cone nozzle, 24-Inner cone, 2401-Inner cone nozzle. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are only a part of the present invention, and not all of it. Other embodiments obtained by those skilled in the art based on these embodiments without creative effort are also within the protection scope of the present invention.

[0023] Reference Figures 1-8 The electrically controlled downhole casing cutting tool includes a connection module and a cutting control module;

[0024] The connection module includes an upper connector 1, a mandrel 2, a cutting housing 3, a short connector 22, an outer cone 23, and an inner cone 24. The upper end of the upper connector 1 is connected to the drill string, and the lower end of the upper connector 1 is connected to the cutting housing 3 by a thread. The mandrel 2 is connected to the upper connector 1 by a thread. The short connector 22 is connected to the cutting housing 3 by a thread. The outer cone 23 is connected to the short connector 22 by a thread. The inner cone 24 is connected to the mandrel 2 by a thread. An inner cone nozzle 2401 is formed on the surface of the inner cone 24, and an outer cone nozzle 2301 is formed on the surface of the outer cone 23. The inner cone nozzle 2401 and the outer cone nozzle 2301 are concentrically fitted. The diameter of the outer cone nozzle 2301 is smaller than the diameter of the inner cone nozzle 2401, so that the working fluid is accelerated by the two-stage nozzles to form a high-pressure jet, which directly acts on the inner wall of the casing to achieve the effect of cleaning the inner wall of the casing.

[0025] The cutting control module includes a control unit base 4, a control unit 5, a battery pack 6, a motor 7, a motor support 8, a lead screw nut 9, a lead screw 10, a push cylinder 11, an electromagnet 12, an armature 13, an armature return spring 14, a lever 15, a thrust ball bearing 16, a tool holder 17, a support frame 18, a tool body 19, a tool body return spring 20, and a spring seat 21. The control unit base 4 is mounted on the surface of the spindle 2. The control unit base 4 is axially positioned by a shaft elastic retaining ring. A wire hole 401 is provided at the lower end of the control unit base 4 for arranging wires to connect the motor 7 and the electromagnet 12. The control unit 5 includes an MCU, a power management circuit, a motor drive circuit, and wireless communication. The circuit, filtering circuit, and electromagnet drive circuit are integrated on the PCB board. The control unit 5 and battery pack 6 are fixed inside the control unit base 4 with bolts. The motor 7 is connected to the motor support 8 with screws. The motor support 8 is fixed to the surface of the spindle 2 with screws. The lead screw nut 9 is fixed to the upper surface of the push cylinder 11 with bolts. The lead screw 10 and the lead screw nut 9 are concentrically fitted. The motor 7 and the lead screw 10 are connected by a coupling. The lead screw 10 is installed in the lead screw guide rail 1101 set in the push cylinder 11. The motor 7, motor support 8, lead screw nut 9, lead screw 10, and lead screw guide rail 1101 are axially evenly distributed in three sets, so that the push cylinder 11 is smoothly pushed out. The push cylinder 11 is concentrically installed with the spindle 2. The armature 12 is installed in the electromagnet groove 1102 on the surface of the push cylinder 11 and fixed with screws. The armature return spring 14 is installed in the armature return spring groove 1103 on the push cylinder 11. The armature 13 is threaded into the armature hole 1501 at the front end of the lever 15. The lever 15 is bolted into the lever positioning hole 1104. The lever 15 can rotate around the lever positioning hole 1104. The armature 13 is fitted into the movable positioning hole 201 on the surface of the spindle 2. There are 14 movable positioning holes 201 axially distributed. Different movable positioning holes 201 correspond to different extension positions of the cutter body 19. After the electromagnet 12 is energized, it attracts the armature 13, so that the push cylinder 11 can move under the action of the motor 7. Axial movement is performed to change the extension position of the cutter body 19. A thrust ball bearing 16 is installed at the lower end of the push cylinder 11, and the cutter holder 17 is installed at the lower end of the thrust ball bearing 16. The two ends of the support frame 18 are respectively connected to the cutter holder hinge 1701 and the cutter body 19 by bolts. The lower end of the cutter body 19 is connected to the cutting shell hinge 301 provided on the surface of the cutting shell 3 by bolts. The cutter body 19 is installed in the cutter body groove 302 provided on the surface of the cutting shell 3. Four sets of cutter bodies 19 are evenly distributed around the circumference to improve cutting efficiency. The cutter body return spring 20 is installed in the spring seat 21 and the return spring groove 1702 provided at the lower end of the cutter holder 17. The spring seat 21 is installed concentrically with the spindle 2, and the spring seat 21 is axially positioned by the short joint 22.

[0026] In this example, the cutting control module is the core module of this tool. Its core function is that the control unit 5 controls the electromagnet 12 to be energized, attracts the armature 13, and unlocks the push cylinder 11. Then, the control unit 5 controls the motor 7 to make the push cylinder 11 move axially under the action of the lead screw 10. When it reaches the target position, the control unit 5 controls the electromagnet 12 to be de-energized, and the armature return spring 14 pushes the lever 15. Under the action of the lever 15, the armature 13 is engaged in the corresponding moving positioning hole 201. At this time, the extension distance of the cutter body 19 also reaches the target pipe diameter.

[0027] Reference Figure 9 In one specific embodiment, after assembling the tool at the wellhead, the tool is lowered into the well, and working fluid is introduced. Before reaching the designated cutting position, the working fluid is sprayed out at high pressure from the outer cone nozzle 2301 under the combined action of the inner cone 24 and the outer cone 23, cleaning the impurities adhering to the inner wall of the casing, improving the service life of the casing, and continuing to clean until near the target position. When the designated position is reached, the working fluid pump pressure is reduced to avoid large-scale tool shaking. At the same time, the ground terminal sends a cutting command to the control unit 5, and the control unit 5 sends a feedback command to the ground terminal, indicating that the cutting command has been received. At this point, the control unit 5 energizes the electromagnet 12, causing it to attract the armature 13 and compress the armature return spring 14, allowing the push cylinder 11 to move axially. Subsequently, the control unit 5 drives the motor 7 to rotate, causing the push cylinder 11 to move axially downwards under the action of the lead screw nut 9 and lead screw 10. The tool holder 17 also moves axially under the action of the push cylinder 11. Under the action of the tool holder 17 and the support frame 18, the tool body 19 extends. When the extended position of the tool body 19 reaches the target pipe diameter, the control unit 5 de-energizes the electromagnet 12, causing the armature return spring 14 to extend. The armature 13 is aligned with the corresponding movable positioning hole 201, and the drill string is rotated to achieve casing cutting. After cutting, if the next size of casing cutting is required, the above steps are repeated until the cutter body 19 extends to the target pipe diameter, and the cutting command is executed. During this process, the control unit 5 needs to obtain the number of revolutions of the motor in both the forward and reverse directions through the encoder of the motor 7 and feed it back to the ground staff. The staff calculates the current position of the armature 13 in the movable positioning hole 201, and thus obtains the current extension distance of the cutter body 19. During the recovery operation, the ground terminal sends a recovery operation command. The control unit 5 controls the electromagnet 12 to be energized, compressing the armature return spring 14 to unlock the push cylinder 11. The control unit 5 drives the motor 7 to rotate, causing the push cylinder 11 to move axially upward. The cutter body 19 retracts under the action of the cutter body return spring 20. When it reaches the initial position, the control unit 5 de-energizes the electromagnet 12, and the armature return spring 14 extends, causing the armature 13 to engage with the corresponding moving positioning hole 201, locking the push cylinder 11 and preventing the cutter body 19 from accidentally extending and scratching the inner wall of the casing. The drill string is then lifted to recover the tool.

Claims

1. An electrically controlled downhole casing cutting tool, characterized in that: The electrically controlled downhole casing cutting tool includes a connection module and a cutting control module; The connection module includes an upper connector (1), a mandrel (2), a cutting shell (3), a short connector (22), an outer cone (23), and an inner cone (24). The upper end of the upper connector (1) is connected to the drill string, and the lower end of the upper connector (1) is connected to the cutting shell (3) by a thread. The mandrel (2) is connected to the upper connector (1) by a thread. The short connector (22) is connected to the cutting shell (3) by a thread. The outer cone (23) is connected to the short connector (22) by a thread. The inner cone (24) is connected to the mandrel (2) by a thread. An inner cone nozzle (2401) is opened on the surface of the inner cone (24), and an outer cone nozzle (2301) is opened on the surface of the outer cone (23). The inner cone nozzle (2401) and the outer cone nozzle (2301) are concentrically fitted. The diameter of the outer cone nozzle (2301) is smaller than the diameter of the inner cone nozzle (2401). The cutting control module includes a control unit base (4), a control unit (5), a battery pack (6), a motor (7), a motor support (8), a lead screw nut (9), a lead screw (10), a push cylinder (11), an electromagnet (12), an armature (13), an armature return spring (14), a lever (15), a thrust ball bearing (16), a tool holder (17), a support frame (18), a tool body (19), a tool body return spring (20), and a spring seat (21). The control unit base (4) is mounted on the surface of the spindle (2). The control unit base (4) is axially positioned by a shaft elastic retaining ring. A wire hole (401) is opened at the lower end of the control unit base (4) for arranging wires to connect the motor (7) and the electromagnet (12). The control unit (5) includes an MCU, a power management circuit, a motor drive circuit, a wireless communication circuit, a filter circuit, and an electromagnet drive circuit, all integrated on a PCB board. The control unit (5) and the battery pack (6) are fixed inside the control unit base (4) by bolts. The motor (7) is connected to the motor support (8) by screws. The motor support (8) is fixed to the surface of the spindle (2) by screws. The lead screw nut (9) is fixed to the upper surface of the push cylinder (11) by bolts. The lead screw (10) and the lead screw nut (9) are concentrically fitted. The motor (7) and the lead screw (10) are connected by a coupling. The lead screw (10) is installed in the lead screw guide rail (1101) set on the push cylinder (11). The motor (7), the motor support (8), and the lead screw nut (9) are all part of the control unit. Three sets of lead screws (10) and lead screw guides (1101) are evenly distributed axially to ensure smooth ejection of the push cylinder (11). The push cylinder (11) is concentrically mounted with the spindle (2). The electromagnet (12) is installed in the electromagnet groove (1102) on the surface of the push cylinder (11) and fixed with screws. The armature return spring (14) is installed in the armature return spring groove (1103) on the push cylinder (11). The armature (13) is threaded into the armature hole (1501) at the front end of the lever (15). The lever (15) is bolted into the lever positioning hole (1104). The lever (15) can rotate around the lever positioning hole (1104). The armature (13) is fitted into the movable positioning hole (201) on the surface of the spindle (2). Fourteen holes (201) are distributed axially. Different moving positioning holes (201) correspond to different extension positions of the cutter body (19). After the electromagnet (12) is energized, it attracts the armature (13), so that the pusher (11) can move axially under the action of the motor (7) to change the extension position of the cutter body (19). The lower end of the pusher (11) is equipped with a thrust ball bearing (16), and the cutter holder (17) is installed at the lower end of the thrust ball bearing (16). The two ends of the support frame (18) are respectively connected to the cutter holder hinge (1701) and the cutter body (19) by bolts. The lower end of the cutter body (19) is connected to the cutting shell hinge (301) set on the surface of the cutting shell (3) by bolts. The cutter body (19) is installed in the cutter body groove (302) set on the surface of the cutting shell (3).Four sets of blade body (19) are evenly distributed around the circumference to improve cutting efficiency. The blade body return spring (20) is installed in the return spring groove (1702) at the lower end of the spring seat (21) and the blade seat (17). The spring seat (21) is concentrically installed with the spindle (2), and the spring seat (21) is axially positioned via a short connector (22).

2. The electrically controlled downhole casing cutting tool according to claim 1, characterized in that: The armature return spring (14) is in a pre-compressed state, so that the armature (13) fits in the movable positioning hole (201) to prevent the push cylinder (11) from moving axially and causing the cutter body (19) to accidentally extend and scratch the well wall.

3. The electrically controlled downhole casing cutting tool according to claim 1, characterized in that: The surface of the blade (19) is provided with high-strength cylindrical teeth, which extends the service life of the blade (19) and improves the cutting efficiency.

4. The electrically controlled downhole casing cutting tool according to claim 1, characterized in that: The motor (7) is equipped with an encoder, which enables the control unit (5) to obtain the current number of rotations of the motor (7) through the encoder, thereby calculating the moving distance of the lead screw (10) and achieving precise control of the armature (13) to fit into the moving positioning hole (201).

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