Energy storage type downhole tubing electric cutting tool with adjustable centralizing mechanism

Abstract

The present application relates to the technical fields of petroleum machinery downhole operation equipment, and discloses an energy storage type downhole tubing electric cutting tool with an adjustable centralizing mechanism, which solves the problem of low positioning accuracy and comprises an upper joint, an electric control unit, an adjustable anchoring and centralizing module, an energy storage sub, a cutting module and a lower joint; the upper and lower double sets of stepping motors are used to drive the ball screw to drive the anchoring slips to stretch and retract, so that the tool can be adaptively attached to oil pipes with different diameters to realize coaxial and central positioning; the torsional spring type energy storage sub is additionally arranged, so that when the cutter is stuck, energy can be stored and released to provide impact torque to assist in unblocking; the cutting module is uniformly provided with three groups of V-shaped micro-textured wear-resistant cutters in the circumferential direction, which have high wear resistance and low friction coefficient, and the wellhead can be replaced without disassembly; the application is also provided with a Hall position sensor to realize stroke closed-loop control and improve positioning accuracy; the overall structure is compact and convenient to operate, and is suitable for downhole tubing cutting operations under different working conditions.

Description

Technical Field

[0001] This invention belongs to the technical field of downhole equipment for petroleum machinery, specifically a storage-type electric downhole tubing cutter with an adjustable centering mechanism. Background Technology

[0002] In downhole workover operations in oil and gas fields, tubing cutting is a crucial step in handling stuck drill bits, well abandonment, and tubing string recovery. Existing downhole electric tubing cutting tools still have several shortcomings: First, the centering mechanisms are mostly of fixed dimensions, unable to adapt to tubing of different diameters, easily leading to eccentric cutting, resulting in uneven cut surfaces, and even tool jamming; second, ordinary cutting tools experience severe wear in the high temperatures and sand-laden media downhole, resulting in short lifespans, and frequent tripping significantly increases operating costs; third, when the cutting tool encounters tubing deformation or hard scale buildup on the inner wall, the motor is prone to overload and shutdown, lacking effective emergency release methods, which can easily cause the tool to fall into the well, posing a safety risk.

[0003] In addition, the existing tools have insufficient electrical control precision, and the anchoring and feed strokes are mostly open-loop controlled, which cannot accurately reflect the actual position of the slips and the cutter, making it difficult to ensure the centering positioning accuracy and feed depth consistency under different pipe diameters. To address these issues, this invention proposes an energy storage type downhole tubing electric cutting tool with an adjustable centering mechanism. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the present invention provides an energy storage type downhole tubing electric cutting tool with an adjustable straightening mechanism, which effectively solves the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an energy storage type downhole tubing electric cutting tool with an adjustable centering mechanism, comprising an upper connector, a cable assembly, an electrical control unit, an end cap, a stepper motor, a fixed centering component, an anchoring module, a housing, screws, a rotary motor, an energy storage sub, a connector, a thrust ball bearing, a power connection shaft, a rotary device housing, a cutting module, a ball screw, and a lower connector; The upper connector is connected to the downhole tubing string. A cable passage is reserved inside the upper connector. The cable assembly passes through the passage and is electrically connected to the electronic control unit. The upper connector is connected to the housing by a threaded seal. The electronic control unit is assembled inside the upper section of the housing. The end cap is fitted to the lower part of the electronic control unit for axial limiting assembly. The fixed centering component is locked and fixed inside the housing by the screws. The stepper motor is mounted in the center of the fixed centering component. The anchoring modules are arranged in two symmetrical sets on the inner side of the housing. The anchoring modules and the stepper motor are driven by the ball screw. The rotary motor is fixed inside the lower section of the housing by the screws. The power output end of the rotary motor is connected and fixed to the energy storage short section key. The bottom end of the energy storage short section is threadedly connected to the power connection shaft. The thrust ball bearing is assembled on the outside of the power connection shaft. The bottom end of the housing is assembled to the outer shell of the rotating device via the connector, the cutting module is integrated inside the outer shell of the rotating device, and the lower connector is a hemispherical structure and is threaded to the bottom end of the outer shell of the rotating device. The fixed centering component is embedded with a Hall position sensor. The Hall position sensor is used to detect the real-time angular displacement signal of the stepper motor rotor and transmit it to the electronic control unit. The electronic control unit adjusts the number of drive pulses of the stepper motor according to the real-time angular displacement signal to control the opening stroke of the anchoring jaws and the extension position of the cutting tool. The electronic control unit is connected to the stepper motor and the rotary motor respectively.

[0006] Preferably, the anchoring module includes an anchoring clip, a connecting rod, a four-legged ball nut, and a bolt. The anchoring clip is detachably mounted to the outer wall of the housing via the nut. The connecting rod is hinged to the inner side of the anchoring clip via the bolt. The inner side of the connecting rod is connected to the four-legged ball nut. The four-legged ball nut is fitted onto the ball screw. The ball screw is coaxially connected to the output shaft of the stepper motor. The outer arc surface of the anchoring slip is machined with dense anti-slip serrations, and the serration parameters are set as follows: tooth pitch 1.5mm, tooth height 0.5mm, and tooth flank angle 60°.

[0007] Preferably, the energy storage section adopts a highly elastic integrated torsion spring structure; Under normal cutting conditions, the energy storage section directly transmits the rated cutting torque of the rotary motor; When the cutting tool encounters deformation of the oil pipe or gets stuck due to hard deposits on the inner wall, the torsion spring undergoes controllable elastic deformation and stores elastic potential energy. Once the stored energy reaches a preset safety threshold, it instantly releases a high-energy impact torque to complete the emergency unblocking operation of the cutting tool.

[0008] Preferably, the connector adopts two sets of symmetrically arranged semi-cylindrical integrated splicing structures. After the two semi-cylindrical connectors are aligned and fitted together, they are locked and fixed by multiple sets of high-strength bearing bolts to achieve a sealed connection between the shell and the outer shell of the rotating device, and to satisfy the coaxial rotational movement of the outer shell of the rotating device relative to the shell.

[0009] Preferably, the cutting module includes three sets of independent cutting arms, which are evenly spaced at 120° intervals along the circumference of the rotating device housing and feed and cut synchronously and collaboratively. Each set of cutting arms includes a cutting tool, a cutting arm, a connecting rod, and a three-legged ball nut. The three-legged ball nut is sleeved on the outside of the corresponding ball screw. The ball screw is connected to a dedicated stepper motor. The three-legged ball nut is hinged to the cutting arm through the connecting rod. The cutting tool is fixedly mounted at the end of the cutting arm.

[0010] Preferably, the cutting tool is a one-piece cemented carbide V-shaped cutter head structure; The cutting tool is processed using a surface micro-textured wear-resistant strengthening process. The V-shaped tool has circular drag-reducing and wear-resistant grooves arranged in an array on both sides of the cutting working surface. The grooves have a diameter of 2.5 mm, a depth of 0.5 mm, and a center-to-center distance of 3 mm between adjacent grooves.

[0011] Preferably, the cutting tool is directly clamped and locked to the end of the blade arm by a protective pressure cap and a disassembly bolt; The stepper motor can drive the cutting tool to extend outside the housing of the rotating device.

[0012] Preferably, the fixed centering component fully covers and fits the outer walls of all the stepper motors, forcibly locking all the stepper motors to be aligned with the coaxial center axis of the fitting tools.

[0013] Preferably, the electronic control unit has an embedded microcontroller, and the output terminal of the microcontroller is electrically connected to the drive circuits of each of the stepper motors and the rotary motors. The electronic control unit receives command signals transmitted by the ground operator through the cable assembly, and outputs drive signals to the corresponding stepper motor or rotary motor according to the command signals.

[0014] This invention also provides a method for using an energy-storage type downhole tubing electric cutting tool with an adjustable centralizing mechanism. Based on the aforementioned energy-storage type downhole tubing electric cutting tool with an adjustable centralizing mechanism, its characteristics are as follows: The electronic control unit receives the anchoring start command signal transmitted from the ground through the cable assembly. After the pulse width modulation signal is generated and processed by the microcontroller embedded in the electronic control unit, a PWM drive signal is obtained and transmitted to the stepper motor to drive the ball screw to rotate and push the four-legged ball nut to move axially, thereby controlling the anchoring slip to open radially and fit against the inner wall of the oil pipe. The electronic control unit receives the feed start command signal transmitted from the ground through the cable assembly. After the step pulse sequence is generated and processed by the microcontroller embedded in the electronic control unit, a step drive signal is obtained and transmitted to the stepper motor corresponding to the cutting module to drive the corresponding ball screw to rotate and push the three-legged ball nut to move axially, thereby controlling the cutter arm to drive the cutting tool to extend radially out of contact with the pipe wall. The electronic control unit receives the rotation start command signal transmitted from the ground through the cable assembly. After the PWM duty cycle adjustment is processed by the microcontroller embedded in the electronic control unit, the duty cycle adjustment signal is obtained and transmitted to the rotating motor to drive the energy storage section and the power connection shaft to drive the outer shell of the rotating device and the internal cutting module to rotate coaxially. The Hall position sensor embedded in the fixed centering component receives the real-time angular displacement signal of the stepper motor rotor. After analog-to-digital conversion and stroke comparison processing by the microcontroller embedded in the electronic control unit, the rotor position signal is obtained and transmitted to the command output port of the electronic control unit to adjust the number of drive pulses of the stepper motor to control the opening stroke of the anchoring jaws and the extension position of the cutting tool.

[0015] Compared with the prior art, the beneficial effects of the present invention are: (1) The adjustable straightening mechanism of this device drives the ball screw through the stepper motor to steplessly open the slip, which can adaptively fit oil pipes of different diameters. With the upper and lower double-set anchoring structure, the tool is coaxially centered throughout the process, avoiding eccentric cutting and ensuring a flat cutting surface. (2) The energy storage section of this device adopts a torsion spring structure. When the cutter encounters deformed pipe wall or hard scale, it can store and release elastic potential energy to provide impact torque to assist in unblocking. At the same time, it buffers the impact of stalling, protects the motor and transmission structure, and reduces the risk of the cutter falling into the well. (3) The cutting tool of this device adopts a V-shaped micro-textured cemented carbide structure, which has both high wear resistance and low friction coefficient, and can greatly extend the service life of the tool; with the modular non-disassembly replacement structure, the cutting head can be replaced directly at the wellhead without disassembling the tool body, reducing maintenance costs.

[0016] (4) This device can detect the angular displacement of the stepper motor rotor in real time by embedding a Hall position sensor in the fixed centering component, and control the opening stroke of the anchoring jaw and the extension position of the tool in a closed loop, thereby improving the positioning accuracy and feed consistency under different pipe diameters and further ensuring the stability of the cutting operation. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0018] In the attached diagram: Figure 1 This is a schematic diagram of the overall structure of the device; Figure 2 This is a schematic cross-sectional view of the entire device; Figure 3 This is a schematic diagram of the overall internal structure of the device; Figure 4This is a schematic diagram of the anchoring module structure of this device; Figure 5 This is a schematic diagram of the cutting module structure of this device; Figure 6 This is a schematic diagram of the energy storage short circuit of this device; Figure 7 This is a schematic diagram of the anchoring slips for this device; Figure 8 This is a schematic diagram of the cutting tool of this device.

[0019] In the diagram: 1-Upper connector; 2-Cable assembly; 3-Electrical control unit; 4-Inner shell end cap; 5-Stepper motor; 6-Fixed centering component; 7-Anchoring module; 8-Fixed centering component; 9-Housing; 10-Screw; 11-Rotating motor; 12-Energy storage section; 13-Connector; 14-Thrust ball bearing; 15-Power connection shaft; 16-Rotating device housing; 17-Cutting module; 18-Lower connector; 19-Ball screw; 7.1-Anchoring slip; 7.2-Connecting rod; 7.3-Four-legged ball nut; 7.4-Bolt; 7.5-Screw; 17.1-Cut tool; 17.2-Gland; 17.3-Connecting rod; 17.4-Cut arm; 17.5-Bolt; 17.6-Nut; 17.7-Three-legged ball nut; 18-Lower connector; 19-Ball screw. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Example 1, by Figures 1-8The present invention provides an energy-storing downhole tubing electric cutting tool with an adjustable centering mechanism, comprising an upper connector 1, a cable assembly 2, an electrical control unit 3, an end cap 4, a stepper motor 5, a fixed centering component 6, an anchoring module 7, a housing 9, a screw 10, a rotary motor 11, an energy-storing sub 12, a connector 13, a thrust ball bearing 14, a power connection shaft 15, a rotary device housing 16, a cutting module 17, a ball screw 19, and a lower connector 18; the upper connector 1 connects to the downhole tubing string, and a cable passage is pre-reserved inside the upper connector 1; the cable assembly 2 passes through the cable... The channel is internal and electrically connected to the electronic control unit 3. The upper connector 1 is threaded and sealed to the housing 9. The electronic control unit 3 is assembled inside the upper section of the housing 9. The end cap 4 fits against the lower part of the electronic control unit 3 for axial limiting assembly to prevent axial displacement of components during tool insertion and operation, ensuring the assembly stability of internal components. The fixed centering component 6 is locked and fixed inside the housing 9 by the screw 10. The stepper motor 5 is positioned at the center of the fixed centering component 6. The anchoring modules 7 are symmetrically arranged in two sets on the upper and lower parts of the housing 9. On the inner side, the anchoring module 7 and the stepper motor 5 are driven by the ball screw 19; the rotary motor 11 is fixed inside the lower section of the housing 9 by the screw 10, and the power output end of the rotary motor 11 is keyed to the energy storage section 12. The bottom end of the energy storage section 12 is threaded to the power connecting shaft 15, and the thrust ball bearing 14 is fitted onto the outside of the power connecting shaft 15; the bottom end of the housing 9 is assembled to the rotating device housing 16 through the connector 13, and the cutting module 17 is integrated outside the rotating device. Inside the housing 16, the lower connector 18 is a hemispherical structure and is threadedly assembled to the bottom of the rotating device housing 16; the fixed centering component 6 has a Hall position sensor embedded in it, which is used to detect the real-time angular displacement signal of the rotor of the stepper motor 5 and transmit it to the electronic control unit 3. The electronic control unit 3 adjusts the number of drive pulses of the stepper motor 5 according to the real-time angular displacement signal to control the opening stroke of the anchoring chuck 7.1 and the extension position of the cutting tool 17.1; the electronic control unit 3 is connected to the stepper motor 5 and the rotary motor 11 respectively. In this embodiment, the upper connector 1 is used to connect with the downhole tubing to realize tool insertion and extraction. The electronic control unit 3 undertakes the functions of receiving signals, processing calculations and outputting drive commands. The upper and lower sets of anchoring modules 7 together constitute an adjustable straightening mechanism. Multi-point radial support ensures that the tool and tubing are coaxial. The energy storage short section 12 is connected in series in the rotary transmission chain to form a passive impact release structure. The cutting module 17 is the execution end for pipe wall cutting. The hemispherical structure of the lower connector 18 can reduce fluid resistance and pipe wall collision damage during the insertion process. In this embodiment, the stepper motor 5 and the ball screw 19 constitute a precision linear drive module. Let the lead of the ball screw 19 be P, the step angle of the stepper motor 5 be θ, and the microstepping of the driver be N. Then, for each drive pulse issued by the electronic control unit 3, the axial linear displacement corresponding to the four-legged ball nut 7.3 is calculated using the following formula: The electronic control unit 3 contains the inner diameter parameter D of the oil pipe to be worked on, and the reference outer diameter d0 of the tool when the anchor slip is fully retracted. Based on this, the target radial opening amount required for the anchor slip 7.1 is calculated using the following formula: The electronic control unit 3 calculates the required total number of drive pulses based on S / Δs. While driving the stepper motor 5, the Hall position sensor embedded in the fixed centering component 6 provides real-time feedback on the pulse count corresponding to the rotor angular displacement, forming a fully closed-loop control. When the actual feedback pulse count reaches the target total number of pulses, the electronic control unit 3 immediately stops the drive output, achieving precise control of the opening stroke of the anchoring slip 7.1. Similarly, the radial feed stroke of the cutting tool 17.1 also adopts the same pulse-displacement calculation logic and closed-loop positioning method to ensure that the cutting depth of each tool is consistent.

[0022] Furthermore, the anchoring module 7 includes an anchoring slip 7.1, a connecting rod 7.2, a four-legged ball nut 7.3, and a bolt 7.4. The anchoring slip 7.1 is detachably mounted to the outer wall of the housing 9 via the nut. The connecting rod 7.2 is hinged to the inner side of the anchoring slip 7.1 via the bolt 7.4. The four-legged ball nut 7.3 is mated to the inner side of the connecting rod 7.2. The four-legged ball nut 7.3 is fitted onto the ball screw 19. The ball screw 19 is coaxially connected to the output shaft of the stepper motor 5. The outer arc surface of the anchoring slip 7.1 is machined with dense anti-slip serrations. The serration parameters are set as follows: tooth pitch 1.5mm, tooth height 0.5mm, and tooth flank angle 60°. During operation, the upper and lower double-set anchoring slips 7.1 open synchronously, firmly gripping the inner wall of the tubing, achieving precise centering of the tool within the tubing string, ensuring a vertical and unbiased cutting surface; the fixed centering component 6 fully covers and fits against the outer wall of all the stepper motors 5, forcibly locking all the stepper motors 5 to be aligned with the coaxial center axis of the tool; the electronic control unit 3 has an embedded microcontroller, the output of which is electrically connected to the drive circuits of each stepper motor 5 and the rotary motor 11; the electronic control unit 3 receives command signals transmitted by the ground operator through the cable assembly 2, and outputs drive signals to the corresponding stepper motor 5 or rotary motor 11 according to the command signals; In this embodiment, the four-legged ball nut 7.3 cooperates with the ball screw 19 to convert the rotational motion of the stepper motor 5 into linear reciprocating motion. The radial extension and retraction of the anchoring jaws 7.1 is achieved through the crank-slider effect of the connecting rod 7.2. All components are connected by bolts. The rigid positioning of the fixed centering component 6 on the stepper motor 5 can eliminate the radial movement of the motor, ensure the coaxiality of the ball screw 19 transmission, and avoid tool skew caused by asynchronous extension and retraction of the jaws. The microcontroller can independently distribute pulses to multiple stepper motors 5 to realize independent driving and coordinated control of the upper and lower anchoring groups and each cutting arm. When in use, after the tool is lowered into the preset cutting section along with the tubing string, the ground control system sends the operation command to the electrical control unit 3 through the cable assembly 2, and first executes the anchoring and centering procedure.

[0023] Furthermore, the energy storage section 12 adopts a high-elasticity integrated torsion spring structure. Under normal cutting conditions, the energy storage section 12 directly transmits the rated cutting torque of the rotary motor 11. When the tool encounters deformation of the oil pipe or jamming due to hard scale on the inner wall, the torsion spring undergoes controllable elastic deformation and stores elastic potential energy. After the stored energy reaches a preset safety threshold, it instantaneously releases high-energy impact torque to complete the emergency tool unblocking operation, while buffering the stall load, protecting the motor and transmission system, and improving the adaptability and operational safety of the tool in complex downhole conditions. Specifically, the upper end of the torsion spring of the energy storage section 12 is circumferentially fixed to the output shaft of the rotary motor 11 via a flat key, and the lower end is circumferentially fixed to the power connection shaft 15 via a spline. During normal rotation, the spring does not undergo relative torsion and rigidly transmits torque. When the cutting tool 17.1 jams, causing the speed of the power connection shaft 15 to be lower than the speed of the rotary motor 11, an angular displacement difference is generated at both ends of the spring, and the spring body undergoes torsional deformation and stores elastic potential energy. As the motor continues to rotate, the torsion angle gradually increases. When the torsion angle reaches the elastic limit angle designed for the spring (e.g., 30°), the spring's elastic potential energy exceeds the jamming resistance, and it rebounds and releases instantaneously, driving the power connection shaft 15 to generate angular acceleration and impact torque, thereby breaking through the jamming point. This process is purely mechanically and automatically triggered, requiring no electrical control intervention, and is rapid and reliable in response. The connector 13 adopts two sets of symmetrically arranged semi-cylindrical integrated splicing structures. After the two semi-cylindrical connectors are aligned and fitted together, they are locked and fixed by multiple sets of high-strength bearing bolts, realizing the sealed docking of the housing 9 and the outer shell 16 of the rotating device, and satisfying the coaxial rotational motion of the outer shell 16 of the rotating device relative to the housing 9. The cutting module 17 includes three sets of independent cutting arms. The three sets of cutting arms are evenly spaced at 120° along the circumference of the outer shell 16 of the rotating device, and synchronously and collaboratively feed for cutting. Each set of cutting arms is equipped with a cutting tool 17.1, a tool arm 17.4, a connecting rod 17.3, and a three-legged ball nut 17.7. The three-legged ball nut 17.7 is sleeved on the outside of the corresponding ball screw 19, and the ball screw 19 is docked with a dedicated... The stepper motor 5 drives the three-legged ball nut 17.7, which is hinged to the cutter arm 17.4 via the connecting rod 17.3. The end of the cutter arm 17.4 is limited and fixed to the cutting tool 17.1. All components are connected by bolts. The cutting tool 17.1 is an integral carbide V-shaped cutter head structure. The cutting tool 17.1 is processed with a surface micro-textured wear-resistant strengthening process. The cutting surfaces on both sides of the V-shaped cutter are arrayed with circular drag-reducing and wear-resistant grooves. The grooves have a diameter of 2.5 mm, a depth of 0.5 mm, and a center-to-center distance of 3 mm between adjacent grooves. The cutting tool 17.1 is directly pressed and locked to the end of the cutter arm 17.4 by the protective cover 17.2 and the disassembly bolts 17.5. The stepper motor 5 can drive the cutting tool 17.1 to extend out of the outer shell 16 of the rotating device. In this embodiment, the two ends of the torsion spring of the energy storage section 12 are circumferentially fixed to the output shaft of the rotary motor 11 and the power connection shaft 15, respectively. Under no jamming conditions, the spring has no relative torsion and rigidly transmits the rated torque. When jamming occurs, the motor end continues to rotate, and the cutter end is obstructed. The spring undergoes torsional deformation to store energy. After the deformation reaches the safety threshold corresponding to the spring's elastic limit, the elastic potential energy is released instantaneously, causing the cutter end to generate a circumferential impact and break through the jamming point. The splicing structure of the connector 13 not only ensures the static seal between the housing 9 and the outer shell 16 of the rotating device, but also through the internal The bearing pair supports the circumferential rotation of the rotating device housing 16, which also facilitates disassembly and maintenance; the synchronous feeding of the three sets of cutting arms can ensure uniform force on the circumferential wall of the pipe, avoiding tool wobble caused by unilateral cutting; the V-shaped cutter head structure can maintain an intact cutting trajectory even when the tubing is subjected to tension, compression, bending deformation; the surface micro-textured grooves can store lubricating medium and wear debris during cutting, reducing the coefficient of friction and wear rate of the cutter face; the wellhead non-disassembly cutter replacement structure can significantly shorten the on-site maintenance time, and the cutter head can be replaced without disassembling the main sealing structure of the tool, avoiding damage to the sealing performance caused by repeated disassembly and assembly; During use, after anchoring, the tool feeding process is executed, controlling the three sets of cutting arms to extend synchronously to the set cutting depth, so that the tool cuts into the inner wall of the pipe. Then, the rotary motor 11 is started to drive the cutting module 17 to rotate circumferentially for continuous pipe wall cutting. If the tool gets stuck due to hard scale or pipe wall deformation during the cutting process, the energy storage section 12 automatically completes the energy storage and release impact to assist the tool in unblocking. After cutting, the cutting tool 17.1 is retracted and the anchoring clip 7.1 is retracted in sequence, and the tool can be pulled to the ground. After the tool wears out, the cutting tool 17.1 is extended out of the rotating device housing 16, the bolts on the tool arm and the tool are removed, the protective cover is removed to replace the tool, the protective cover is put back on, and the bolts are re-fixed. The new cutter head can be replaced by removing the protective cover 17.2 and the disassembly bolt 17.5.

[0024] This embodiment describes a method for using an energy-storage type downhole tubing electric cutting tool with an adjustable centralization mechanism. Based on the aforementioned energy-storage type downhole tubing electric cutting tool with an adjustable centralization mechanism, its key feature is: The electronic control unit 3 receives the anchoring start command signal transmitted from the ground via the cable assembly 2. After the pulse width modulation signal is generated and processed by the microcontroller embedded in the electronic control unit 3, a PWM drive signal is obtained and transmitted to the stepper motor 5 to drive the ball screw 19 to rotate and push the four-legged ball nut 7.3 to move axially, thereby controlling the anchoring slip 7.1 to open radially and fit against the inner wall of the oil pipe. The electronic control unit 3 receives the feed start command signal transmitted from the ground via the cable assembly 2. After the step pulse sequence is generated and processed by the microcontroller embedded in the electronic control unit 3, a step drive signal is obtained and transmitted to the stepper motor 5 corresponding to the cutting module 17 to drive the corresponding ball screw 19 to rotate and push the three-legged ball nut 17.7 to axially displace, thereby controlling the cutter arm 17.4 to drive the cutting tool 17.1 to extend radially out of contact with the pipe wall. The electronic control unit 3 receives the rotation start command signal transmitted from the ground via the cable assembly 2. After the PWM duty cycle adjustment is processed by the microcontroller embedded in the electronic control unit 3, the duty cycle adjustment signal is obtained and transmitted to the rotary motor 11 to drive the energy storage section 12 and the power connection shaft 15 to drive the rotating device housing 16 and the internal cutting module 17 to rotate coaxially. The Hall position sensor embedded in the fixed centering component 6 receives the real-time angular displacement signal of the rotor of the stepper motor 5. After analog-to-digital conversion and stroke comparison processing by the microcontroller embedded in the electronic control unit 3, the rotor position signal is obtained and transmitted to the command output port of the electronic control unit 3 to adjust the number of drive pulses of the stepper motor 5 to control the opening stroke of the anchoring chuck 7.1 and the extension position of the cutting tool 17.1.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A storage-type electric downhole tubing cutter with an adjustable centering mechanism, characterized in that: Includes an upper connector (1), a cable assembly (2), an electrical control unit (3), an end cap (4), a stepper motor (5), a fixed centering component (6), an anchoring module (7), a housing (9), screws (10), a rotary motor (11), an energy storage sub (12), a connector (13), a thrust ball bearing (14), a power connection shaft (15), a rotating device housing (16), a cutting module (17), a ball screw (19), and a lower connector (18); The upper connector (1) is connected to the downhole tubing string. The upper connector (1) has a reserved cable passage. The cable assembly (2) is installed inside the passage and is electrically connected to the electrical control unit (3). The upper connector (1) is connected to the housing (9) by a threaded seal. The electrical control unit (3) is assembled inside the upper section of the housing (9). The end cap (4) is fitted to the lower part of the electrical control unit (3) for axial limiting assembly. The fixed centering component (6) is locked and fixed inside the housing (9) by the screw (10). The stepper motor (5) is mounted in the center of the fixed centering component (6). The anchoring module (7) is arranged in two symmetrical groups on the inner side of the housing (9). The anchoring module (7) and the stepper motor (5) are driven by the ball screw (19). The rotary motor (11) is fixed inside the lower section of the housing (9) by the screw (10). The power output end of the rotary motor (11) is keyed to the energy storage section (12). The bottom end of the energy storage section (12) is threadedly connected to the power connection shaft (15). The thrust ball bearing (14) is fitted onto the outside of the power connection shaft (15). The bottom end of the housing (9) is assembled with the outer shell of the rotating device (16) through the connector (13), the cutting module (17) is integrated inside the outer shell of the rotating device (16), and the lower connector (18) is a hemispherical structure and is assembled with the bottom end of the outer shell of the rotating device (16) by threads. The fixed centering component (6) is embedded with a Hall position sensor. The Hall position sensor is used to detect the real-time angular displacement signal of the rotor of the stepper motor (5) and transmit it to the electronic control unit (3). The electronic control unit (3) adjusts the number of drive pulses of the stepper motor (5) according to the real-time angular displacement signal to control the opening stroke of the anchoring chuck (7.1) and the extension position of the cutting tool (17.1). The electronic control unit (3) is connected to the stepper motor (5) and the rotary motor (11) respectively.

2. The energy storage type downhole tubing electric cutting tool with an adjustable centering mechanism according to claim 1, characterized in that: The anchoring module (7) includes an anchoring clip (7.1), a connecting rod (7.2), a four-legged ball nut (7.3), and a bolt (7.4). The anchoring clip (7.1) is detachably mounted on the outer wall of the housing (9) via the nut. The connecting rod (7.2) is hinged to the inner side of the anchoring clip (7.1) via the bolt (7.4). The inner side of the connecting rod (7.2) is connected to the four-legged ball nut (7.3). The four-legged ball nut (7.3) is fitted onto the ball screw (19). The ball screw (19) is coaxially connected to the output shaft of the stepper motor (5). The outer arc surface of the anchoring slip (7.1) is machined with dense anti-slip serrations, and the serration parameters are set as follows: tooth pitch 1.5mm, tooth height 0.5mm, and tooth flank angle 60°.

3. The energy storage type downhole tubing electric cutting tool with an adjustable centering mechanism according to claim 2, characterized in that: The energy storage section (12) adopts a high-elasticity integrated torsion spring structure; Under normal cutting conditions, the energy storage section (12) directly transmits the rated cutting torque of the rotary motor (11); When the cutting tool encounters deformation of the oil pipe or gets stuck due to hard deposits on the inner wall, the torsion spring undergoes controllable elastic deformation and stores elastic potential energy. Once the stored energy reaches a preset safety threshold, it instantly releases a high-energy impact torque to complete the emergency unblocking operation of the cutting tool.

4. The energy storage type downhole tubing electric cutting tool with an adjustable centering mechanism according to claim 3, characterized in that: The connector (13) adopts two sets of symmetrically arranged semi-cylindrical integrated splicing structures. After the two semi-cylindrical connectors are aligned and fitted together, they are locked and fixed by multiple sets of high-strength bearing bolts to achieve the sealed docking of the shell (9) and the outer shell (16) of the rotating device, and to satisfy the coaxial rotational movement of the outer shell (16) of the rotating device relative to the shell (9).

5. A storage-type downhole tubing electric cutting tool with an adjustable centering mechanism according to claim 4, characterized in that: The cutting module (17) includes three sets of independent cutting arms. The three sets of cutting arms are evenly spaced at 120° along the circumference of the rotating device housing (16) and feed and cut synchronously and in coordination. Each set of cutting arms includes a cutting tool (17.1), a cutting arm (17.4), a connecting rod (17.3), and a three-legged ball nut (17.7). The three-legged ball nut (17.7) is sleeved on the outside of the corresponding ball screw (19). The ball screw (19) is connected to the dedicated drive stepper motor (5). The three-legged ball nut (17.7) is hinged to the cutting arm (17.4) through the connecting rod (17.3). The cutting tool (17.1) is fixedly mounted at the end of the cutting arm (17.4).

6. A storage-type downhole tubing electric cutting tool with an adjustable centering mechanism according to claim 5, characterized in that: The cutting tool (17.1) is a one-piece cemented carbide V-shaped cutting head structure; The cutting tool (17.1) is processed using a surface micro-textured wear-resistant strengthening process. The V-shaped tool has circular drag-reducing and wear-resistant grooves arranged in an array on both sides of the cutting working surface. The grooves have a diameter of 2.5 mm, a depth of 0.5 mm, and a center-to-center distance of 3 mm between adjacent grooves.

7. A storage-type downhole tubing electric cutting tool with an adjustable centering mechanism according to claim 6, characterized in that: The cutting tool (17.1) is directly pressed and locked to the end of the blade arm (17.4) by the protective cover (17.2) and the disassembly bolt (17.5); The stepper motor (5) can drive the cutting tool (17.1) to extend outside the housing (16) of the rotating device.

8. A storage-type downhole tubing electric cutting tool with an adjustable centering mechanism according to claim 7, characterized in that: The fixed centering component (6) fully covers and fits the outer sidewalls of all the stepper motors (5), and forcibly locks all the stepper motors (5) to be fitted with the tool on the same central axis.

9. A storage-type downhole tubing electric cutting tool with an adjustable centering mechanism according to claim 8, characterized in that: The electronic control unit (3) has a built-in microcontroller, and the output terminal of the microcontroller is electrically connected to the drive circuits of each stepper motor (5) and the rotary motor (11); The electronic control unit (3) receives the command signal transmitted by the ground operator through the cable assembly (2), and outputs the drive signal to the corresponding stepper motor (5) or rotary motor (11) according to the command signal.

10. A method of using an energy-storage type downhole tubing electric cutting tool with an adjustable centralizing mechanism, based on the energy-storage type downhole tubing electric cutting tool with an adjustable centralizing mechanism as described in claim 9, characterized in that: The electrical control unit (3) receives the anchoring start command signal transmitted from the ground through the cable assembly (2). After the pulse width modulation signal is generated and processed by the microcontroller embedded in the electrical control unit (3), a PWM drive signal is obtained and transmitted to the stepper motor (5) to drive the ball screw (19) to rotate and push the four-legged ball nut (7.3) to axially displace, thereby controlling the anchoring slip (7.1) to radially open and fit against the inner wall of the oil pipe. The electronic control unit (3) receives the feed start command signal transmitted from the ground through the cable assembly (2). After the step pulse sequence is generated and processed by the microcontroller embedded in the electronic control unit (3), a step drive signal is obtained and transmitted to the step motor (5) corresponding to the cutting module (17) to drive the corresponding ball screw (19) to rotate and push the three-legged ball nut (17.7) to axially displace, and control the cutter arm (17.4) to drive the cutting tool (17.1) to extend radially out of contact with the pipe wall; The electronic control unit (3) receives the rotation start command signal transmitted from the ground via the cable assembly (2). After the PWM duty cycle adjustment is processed by the microcontroller embedded in the electronic control unit (3), the duty cycle adjustment signal is obtained and transmitted to the rotary motor (11) to drive the energy storage section (12) and the power connection shaft (15) to drive the outer shell (16) of the rotating device and the internal cutting module (17) to rotate coaxially. The Hall position sensor embedded in the fixed centering component (6) receives the real-time angular displacement signal of the rotor of the stepper motor (5). After analog-to-digital conversion and stroke comparison processing by the microcontroller embedded in the electronic control unit (3), the rotor position signal is obtained and transmitted to the command output port of the electronic control unit (3) to adjust the number of drive pulses of the stepper motor (5) to control the opening stroke of the anchoring chuck (7.1) and the extension position of the cutting tool (17.1).

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