A downhole vibratory unthreading device and method of controlling the same

Abstract

The application discloses a downhole vibration buckle loosening device and a control method thereof. After a magnetic field is generated by energizing a first electromagnet and a second electromagnet, the second electromagnet is repeatedly impacted on a force transmission piston in a sliding cavity under the driving of the magnetic force with the direction changed by controlling the polarity direction of the first electromagnet or the second electromagnet. The force transmission piston is in sliding connection with the inner wall of the inlet section of the oil cylinder, so that the force received by the force transmission piston is transmitted to the force transmission medium of the oil cylinder. The first reset spring is used for resetting when the force transmission piston is not subjected to force. The vibrating member is in sliding connection with the inner wall of the outlet section of the oil cylinder, and is used for impacting a target object under the driving of the force transmission medium to generate vibration. The second reset spring is used for resetting when the vibrating member is not subjected to force. Finally, the buckle loosening device continuously impacts the coupling based on the resonance frequency. The application realizes the loosening of the impurities adhered in the thread gap of the coupling, loosens the thread buckle between the coupling and the casing, and ensures that the subsequent back-off operation can smoothly remove the coupling.

Description

Technical Field

[0001] This invention relates to the field of oil well casing maintenance technology, and in particular to a downhole vibration loosening device and its control method. Background Technology

[0002] During well workover operations, casing damage is frequently encountered, such as a casing rupture somewhere downhole. To ensure normal oil and gas production, the ruptured casing needs to be repaired, and casing replacement is a common repair method. In actual repair processes, a common problem arises: the casing coupling and male thread are rusted and stuck together, especially prevalent in high-temperature oil wells. The conventional approach is to search for a coupling that can be reversed, but this is extremely wasteful, wasting both time and materials. In some wells, no reversible coupling can be found, forcing the casing to be cut and then reconnected. However, this reconnection process often results in a less secure seal than using a single, intact casing. Therefore, a device or method is needed to quickly loosen the threads of such couplings. Summary of the Invention

[0003] This invention provides a downhole vibration uncoupling device and its control method, which solves the technical problem in the prior art where the casing and coupling cannot be separated due to rust and adhesion. By continuously vibrating the coupling, the technical effect of separating the casing and coupling is achieved.

[0004] To address the aforementioned technical problems, embodiments of the present invention provide the following technical solutions:

[0005] In a first aspect, a downhole vibration uncoupling device is provided, comprising:

[0006] The outer casing contains, in sequence, a first electromagnet, a second electromagnet, a force-transmitting piston, a hydraulic cylinder, and a vibrating component.

[0007] The second electromagnet is slidably connected to the sliding cavity of the outer shell. One end of the sliding cavity is provided with the first electromagnet, and the other end of the sliding cavity is provided with the force-transmitting piston. After the first electromagnet and the second electromagnet are energized to generate a magnetic field, the polarity direction of the first electromagnet or the second electromagnet is controlled so that the second electromagnet, driven by the changing magnetic force, repeatedly vibrates the force-transmitting piston in the sliding cavity.

[0008] The aforementioned force-transmitting piston is slidably connected to the inner wall of the inlet section of the aforementioned oil cylinder, so as to transmit the force received by the aforementioned force-transmitting piston to the force-transmitting medium of the aforementioned oil cylinder.

[0009] One end of the force transmission piston is connected to the oil cylinder through a first reset spring, and is used to reset when the force transmission piston is not under force;

[0010] The vibration member is in sliding connection with the inner wall of the outlet section of the oil cylinder, and is used to shock a target object and generate vibration under the drive of the force transmission medium;

[0011] One end of the vibration member is connected to the oil cylinder through a second reset spring, and is used to reset when the vibration member is not under force.

[0012] Optionally, the second electromagnet includes a coil and a core penetrating the coil, the coil is fixed in the sliding cavity and does not contact the core, and the core is in sliding connection with the sliding cavity; after the first electromagnet and the second electromagnet are energized to generate a magnetic field, the core is driven in the sliding cavity to repeatedly shock the force transmission piston under the drive of the magnetic field with changing direction.

[0013] Optionally, the length of the core is greater than the length of the coil, and the coil is completely sleeved on the core during the repeated shocking of the core to the force transmission piston.

[0014] Optionally, a first limiting member is further arranged between the coil and the force transmission piston, a limiting boss is arranged on the limiting member, and a second limiting member adapted to the limiting boss is arranged on the core; when the first electromagnet and the second electromagnet are attracted to each other, the limiting boss and the second limiting member are abutted to keep the core and the first electromagnet apart by a preset distance.

[0015] Optionally, the device further includes a weight to adjust the overall weight of the device.

[0016] Optionally, a lifting ring is arranged on the end of the shell close to the wellhead, and the lifting ring is connected to the ground through a cable.

[0017] Optionally, the device further includes a cable car, the cable car is connected to the lifting ring through a cable, and the position of the loosening device lowered is determined by the length of the cable.

[0018] In a second aspect, a downhole vibration loosening device control method is provided, applied to the loosening device, and the method includes:

[0019] In response to the lowering signal of the control terminal, the cable car lowers the loosening device to a target position;

[0020] A plurality of single pulse signals containing different control parameters are respectively sent through the control terminal, and the loosening device shocks the coupling on the oil well casing according to different control parameters.

[0021] According to the vibration sensor arranged on the above-mentioned coupling, vibration curves corresponding to the jarring under different control parameters are obtained.

[0022] According to the resonance characteristics, from the above-mentioned multiple vibration curves, the resonance frequency and the corresponding resonance control parameter meeting the above-mentioned resonance characteristics are screened out.

[0023] In the above-mentioned control terminal, according to the above-mentioned resonance control parameter, a continuous pulse is sent to the above-mentioned loosening device, so that the above-mentioned loosening device continuously jarrs the above-mentioned coupling.

[0024] Optionally, the step that the cable car lowers the above-mentioned loosening device to the target position specifically includes:

[0025] When the above-mentioned cable car lowers the above-mentioned loosening device by a preset distance from the above-mentioned target position, the lowering speed of the above-mentioned cable car is reduced to a preset speed;

[0026] When the above-mentioned loosening device reaches the above-mentioned target position at the preset speed, the lowering length of the above-mentioned cable car is compared with the actual depth of the above-mentioned coupling; and the comparison result is corrected until the comparison result meets a preset range.

[0027] Optionally, the step that the above-mentioned loosening device continuously jarrs the above-mentioned coupling further includes:

[0028] The above-mentioned cable car is controlled to drive the above-mentioned loosening device to move to the male buckle matched with the above-mentioned coupling, and the above-mentioned male buckle is jarrred.

[0029] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0030] In the embodiments of the present application, the downhole vibration loosening device drives the vibration member to jar the coupling of the casing by controlling the magnetic force direction of the two electromagnets to make the iron core reciprocate, so that the coupling is vibrated and the impurities adhered in the thread gap of the coupling are jarred loose, thereby loosening the thread of the coupling and the casing, and ensuring that the subsequent back-off operation can smoothly disassemble the coupling.

[0031] The control method of the downhole vibration loosening device in the embodiments of the present application first uses multiple single-pulse jarring to detect the vibration frequency curve of the coupling by using a vibration sensor, and screens out the resonance frequency therefrom. The coupling is vibrated based on the resonance frequency, so as to improve the efficiency of jarred impurities in the thread gap of the coupling and more quickly reduce the strength of the impurity adhesion force. It is ensured that the subsequent back-off operation can smoothly disassemble the coupling. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings described in the following embodiment description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without creative labor.

[0033] Figure 1 A structure schematic diagram of a downhole vibration loosening device provided by the present application;

[0034] Figure 2 A structure schematic diagram of a top part of the loosening device in the present application;

[0035] Figure 3 A structure schematic diagram of the loosening device when the first electromagnet and the second electromagnet attract each other in the present application;

[0036] Figure 4 A structure schematic diagram of the loosening device when the first electromagnet and the second electromagnet repel each other in the present application;

[0037] Figure 5 A downhole vibration loosening device and a control method thereof provided by the present application.

[0038] The reference signs: 1, shell; 11, weight; 12, lifting ring; 2, first electromagnet; 3, second electromagnet; 31, coil; 32, iron core; 321, second limiting piece; 4, force transmission piston; 41, first return spring; 5, oil cylinder; 51, force transmission medium; 6, vibration piece; 61, second return spring; 7, first limiting piece; 71, limiting boss; 8, sleeve; 9, coupling. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0041] It should be noted that like numerals and letters refer to like items throughout the several views, and once an item is defined in one view, it should not require further defining and explaining in subsequent views.

[0042] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "arranged", "connected" should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or integrally connected, can be mechanically connected, or can be electrically connected, can be directly connected, or indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In addition, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0043] It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, and are not limitations of the technical solutions of the present application, and the technical features in the embodiments and the embodiments can be combined with each other without conflict.

[0044] The technical scheme of the embodiment of the present application is to solve the above technical problems, and the general idea is as follows:

[0045] The butt joint 9 is vibrated, the adhesion of impurities in the thread gap is loosened by the generated vibration, the strength of the adhesion force is reduced, and the butt joint 9 can be smoothly disassembled in subsequent back-off operation.

[0046] In the embodiment of the present application, a downhole vibration loosening device is provided as shown in Figure 1 The first electromagnet 2, the second electromagnet 3, the force transmission piston 4, the oil cylinder 5 and the vibration piece 6 are sequentially arranged in the shell 1. First, in the structure for generating vibration, reciprocating motion is required, and has the functions of fast response and variable frequency. Under this requirement, whether it is a linear motor or a hydraulic cylinder, although it can do reciprocating motion, the frequency cannot be changed, and the response speed is slow. Therefore, the magnetic driving mode is adopted in the embodiment.

[0047] Specifically, the second electromagnet 3 is slidably connected with the sliding cavity of the shell 1, one end of the sliding cavity is provided with the first electromagnet 2, and the other end of the sliding cavity is provided with the force transmission piston 4; after the first electromagnet 2 and the second electromagnet 3 are electrified to generate a magnetic field, the polarity direction of the first electromagnet 2 or the second electromagnet 3 is controlled, so that the second electromagnet 3 is driven by the magnetic force with the direction changed, and repeatedly strikes the force transmission piston 4 in the sliding cavity;

[0048] It should be noted that the first electromagnet 2 is fixed in the embodiment, and the second electromagnet 3 is driven to shock the transmission piston 4. The first electromagnet 2 and the second electromagnet 3 can be connected with the power source outside the well through a cable, or a mobile power source can be arranged in the shell 1 to supply power to the first electromagnet 2 and the second electromagnet 3. The operation principle is that the magnetic force direction of one of the two electromagnets is unchanged, and the magnetic force of the other electromagnet is changed, so that the second electromagnet 3 is subjected to magnetic forces in different directions, and the second electromagnet 3 makes reciprocating motion, and then repeatedly shocks the transmission piston 4. For example, as shown in Figure 3 , when the polarity direction of the first electromagnet 2 is unchanged, the polarity direction of the second electromagnet 3 is opposite to that of the first electromagnet 2, according to the principle that opposite poles attract each other, the second electromagnet 3 moves towards the first electromagnet 2. As shown in Figure 4 , when the polarity direction of the second electromagnet 3 is changed to be the same as that of the first electromagnet 2, according to the principle that like poles repel each other, the second electromagnet 3 moves away from the first electromagnet 2. When the frequency of the shock transmission piston 4 needs to be changed, the current of the electromagnet coil 31 is only needed to be increased or decreased, so that the magnetic force is changed, and the movement speed of the second electromagnet 3 is also changed, so that the shock is performed according to the preset frequency.

[0049] In addition, one of the first electromagnet 2 and the second electromagnet 3 can be selected to be a permanent magnet, and the same effect can still be achieved. The two electromagnets in the embodiment can expand the range of magnetic force change, and the magnetic force of the two electromagnets can be self-set, so that errors and deviations are reduced.

[0050] The transmission piston 4 is in sliding connection with the inner wall of the inlet section of the oil cylinder 5, so as to transmit the force received by the transmission piston 4 to the transmission medium 51 of the oil cylinder 5; one end of the transmission piston 4 is connected with the oil cylinder 5 through the first reset spring 41, and is used for resetting when the transmission piston 4 is not subjected to force. In the structure, the transmission piston 4 needs to be reset by the first reset spring 41 for the next shock because the transmission piston 4 needs to be repeatedly subjected to the force of the shock to the transmission medium 51. The second reset spring 61 has the same effect and principle as the first reset spring 41. The transmission medium 51 can be hydraulic oil.

[0051] The vibration piece 6 is in sliding connection with the inner wall of the outlet section of the oil cylinder 5, and is used for shocking a target object under the drive of the transmission medium 51 to generate vibration; one end of the vibration piece 6 is connected with the oil cylinder 5 through the second reset spring 61, and is used for resetting when the vibration piece 6 is not subjected to force.

[0052] It should be noted that the target object in this embodiment is the coupling 9 on the oil well casing 8. Since the oil well itself is a cylinder and has a large depth, if the force transmission piston 4 directly hits the coupling 9, the casing 8 cannot accommodate this structure. Therefore, the oil cylinder 5 is used to transmit the kinetic energy of the force transmission piston 4 to the vibration piece 6 in the horizontal direction through the force transmission medium 51, so that the vertical kinetic energy is changed into horizontal kinetic energy, so as to meet the vibration piece 6 directly against the coupling 9 for percussion. Since the force transmission medium 51 is a liquid, the vibration piece 6 can transmit kinetic energy in the direction of movement of the force transmission medium 51 regardless of the direction in which it is arranged.

[0053] Further, as shown in Figure 1 , the second electromagnet 3 includes a coil 31 and a core 32 passing through the coil 31, the coil 31 is fixed in the sliding cavity and does not contact the core 32, and the core 32 is in sliding connection with the sliding cavity; for generating a magnetic field after the first electromagnet 2 and the second electromagnet 3 are energized, by controlling the magnetic field direction of the second electromagnet, the core 32 is driven by the magnetic force with the direction changed in the sliding cavity. Repeatedly percussion on the force transmission piston 4.

[0054] It should be noted that the electromagnet will be wrapped around the outer wall of the core 32. If the second electromagnet 3 as a whole slides in the sliding cavity, it will inevitably cause the coil 31 to wear. Even if a protective shell is added outside, the line connecting the coil 31 and the power supply will also be damaged in the constant movement. Therefore, the coil 31 is fixed in the sliding cavity and does not contact the core 32, and the core 32 is in sliding connection with the sliding cavity. This ensures the safety of the line connecting the coil 31 and the external power supply, and improves the service life of the device.

[0055] Further, as shown in Figure 1 , the length of the core 32 is greater than the length of the coil 31, and in the process of the core 32 repeatedly percussion on the force transmission piston 4, the coil 31 is completely sleeved on the core 32.

[0056] It should be noted that ensuring that the coil 31 is completely sleeved on the core 32 can make the entire magnetic field of the coil 31 participate in work, thereby more accurately controlling the generated magnetic force, and further accurately controlling the movement frequency of the core 32.

[0057] Further, as shown in Figure 1 , the coil 31 and the force transmission piston 4 are further provided with a first limiting piece 7, the limiting piece is provided with a limiting boss 71, and the core 32 is provided with a second limiting piece 321 matched with the limiting boss 71; for when the first electromagnet 2 and the second electromagnet 3 are attracted to each other, the limiting boss 71 and the second limiting piece 321 are abutted to keep the core 32 and the first electromagnet 2 apart by a predetermined distance.

[0058] It should be noted that the first limiting piece 7 is to separate the coil 31 and the force transmission piston 4, and leave the movement distance of the core 32, and then in the design, the size of the first limiting piece 7 can be designed according to the movement length of the core 32. The limiting boss 71 is to block the second limiting piece 321, so as to avoid the core 32 from impacting the first electromagnet 2 and causing damage to the magnet.

[0059] Further, as shown in 2, the slackening device further comprises a weight 11 to adjust the overall weight of the device.

[0060] It should be noted that, due to a large amount of formation fluid in the well, the formation fluid will generate a large buoyancy on the entering slackening device, and in addition, there is a friction force between the slackening device and the well wall in the well; therefore, the weight 11 is arranged to add additional gravity, so that the slackening device can be smoothly lowered.

[0061] Further, as shown in Figure 2 The shell 1 is provided with a lifting ring 12 near one end of the well mouth, and the lifting ring 12 is connected with the ground through a cable. In addition, it further comprises a cable car connected with the lifting ring 12 through the cable, for judging the position of the slackening device lowered through the length of the cable. The position of the lifting ring 12

[0062] Based on the same inventive concept, the embodiments of the present application provide a downhole vibration slackening device control method as shown in Figure 5 The method comprises steps S101-S105:

[0063] Step S101, in response to the lowering signal of the control terminal, the cable car lowers the slackening device to the target position;

[0064] It should be noted that when the cable car lowers the slackening device, 20 meters away from the target position, the lowering speed of the cable car is reduced to a preset speed; the preset speed here can be set to a small constant speed, or the speed can be reduced in steps, so as to slowly reach the target position and avoid deviation from the target due to too fast speed. When the slackening device reaches the target position according to the preset speed, the actual depth of the coupling 9 is compared according to the lowering length of the cable car; according to the comparison result, the cable machine is controlled to continue to lower the slackening device 2 meters, and if the lowering length is 100 meters and the actual depth of the coupling 9 is 102 meters, the cable machine is controlled to continue to lower the slackening device 2 meters, and if the lowering length is 100 meters and the actual depth of the coupling 9 is 98 meters, the cable machine is controlled to ascend the slackening device 2 meters, until the comparison result meets the preset range. Thus it is judged that the slackening device reaches the target position. The preset range can be set to the difference between the lowering length and the actual depth of the coupling 9 is 2 centimeters, and the specific range can be set according to the size of the coupling 9 or actual needs.

[0065] Step S102, a plurality of single pulse signals containing different control parameters are respectively sent out by the control terminal; the loosening device respectively shocks the coupling 9 on the oil well casing 8 according to different control parameters;

[0066] Step S103, the vibration curves corresponding to the shock under different control parameters are obtained according to the vibration sensor arranged on the coupling 9;

[0067] It should be noted that the single pulse signal is mainly transmitted by the control terminal to obtain the vibration of the coupling 9 under the corresponding control parameter through each shock. The control parameter includes the current supplied to the first electromagnet 2 and the second electromagnet 3, and the time of polarity change.

[0068] Step S104, the resonance frequency and the corresponding resonance control parameter meeting the resonance characteristic are selected from the plurality of vibration curves according to the resonance characteristic;

[0069] It should be noted that resonance refers to the phenomenon that energy is transmitted back and forth in the object and is enhanced. When the vibration frequency of the coupling 9 is equal to the natural frequency thereof, the amplitude will rapidly increase, thereby accelerating the loosening speed of the adhering impurities in the thread gap between the casing 8 and the coupling 9. As for the setting of the resonance characteristic, it is not necessarily required to set a frequency completely equal to the coupling 9. Because the plurality of single pulses cannot completely and accurately reflect the standard resonance frequency, the frequency with the largest amplitude can be selected as the resonance characteristic from the plurality of obtained frequency curves.

[0070] Step S105, the continuous pulse is sent to the loosening device according to the resonance control parameter in the control terminal, so that the loosening device continuously shocks the coupling 9. That is to say, after the control parameter corresponding to the vibration frequency is found, the single pulse is not required to be sent, and the continuous pulse is used to accelerate the vibration efficiency and rapidly loosen the adhering impurities between the casing 8 and the coupling 9.

[0071] In addition, since the coupling 9 and the casing 8 are connected through the male buckle and the female buckle, the main position of loosening is the male buckle. Therefore, in order to further improve the shock efficiency, the cable car can be controlled to drive the loosening device to move to the male buckle matched with the coupling 9 to shock the male buckle. Because the position of the male buckle is very close to the coupling 9, it only needs to be offset up and down according to the size of the coupling 9. Thus, the loosening is faster.

[0072] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the changes and modifications falling within the scope of the present application.

[0073] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A downhole vibratory unthreader characterized by, The device comprises: a housing, a first electromagnet, a second electromagnet, a force transmission piston, a cylinder and a vibrating member arranged in the housing in sequence; the second electromagnet is in sliding connection with a sliding cavity of the housing, one end of the sliding cavity is provided with the first electromagnet, and the other end of the sliding cavity is provided with the force transmission piston; after the first electromagnet and the second electromagnet generate a magnetic field after being powered, the polarity direction of the first electromagnet or the second electromagnet is controlled, so that the second electromagnet is driven by the magnetic force with a changing direction in the sliding cavity to repeatedly shock the force transmission piston; the force transmission piston is in sliding connection with the inner wall of the inlet section of the cylinder, so as to transmit the force received by the force transmission piston to the force transmission medium of the cylinder; one end of the force transmission piston is connected with the cylinder through a first reset spring, so as to reset when the force transmission piston is not under force; the vibrating member is in sliding connection with the inner wall of the outlet section of the cylinder, so as to shock a target object under the driving of the force transmission medium to generate vibration; one end of the vibrating member is connected with the cylinder through a second reset spring, so as to reset when the vibrating member is not under force; the second electromagnet comprises a coil and a core penetrating the coil, the coil is fixed in the sliding cavity and does not contact the core, and the core is in sliding connection with the sliding cavity; after the first electromagnet and the second electromagnet generate a magnetic field after being powered, the magnetic field direction of the second electromagnet is controlled, so that the core is driven by the magnetic force with a changing direction in the sliding cavity to repeatedly shock the force transmission piston; the length of the core is greater than the length of the coil, and the coil is completely sleeved on the core in the process of repeatedly shocking the force transmission piston by the core; a first limiting member is further arranged between the coil and the force transmission piston, a limiting boss is arranged on the limiting member, and a second limiting member adapted to the limiting boss is arranged on the core; when the first electromagnet and the second electromagnet are attracted to each other, the limiting boss and the second limiting member are abutted to keep the core and the first electromagnet apart by a preset distance.

2. The release device of claim 1, wherein The device further comprises a weight to adjust the overall weight of the device.

3. The release device of claim 1, wherein A lifting ring is arranged on one end of the housing close to the wellhead, and the lifting ring is connected with the ground through a cable.

4. The release device of claim 3, wherein The device further comprises a cable car connected with the lifting ring through a cable, so as to determine the position of the loosening device lowered through the length of the cable.

5. A method of controlling a downhole vibratory unthreading device, the method comprising: The device is applied to the loosening device of any one of claims 1-4. The method comprises: in response to the lowering signal of the control terminal, the cable car lowers the loosening device to a target position; a plurality of single pulse signals containing different control parameters are respectively sent through the control terminal; the loosening device shocks the coupling on the oil well casing according to different control parameters; the vibration curves corresponding to the shocks under different control parameters are obtained according to the vibration sensor arranged on the coupling; the resonance frequency and the corresponding resonance control parameter meeting the resonance characteristics are screened from the plurality of vibration curves according to the resonance characteristics. In the control terminal, according to the resonance control parameter, a continuous pulse is sent to the loosening device to make the loosening device continuously shock the coupling.

6. The control method according to claim 5, characterized by, The step of lowering the loosening device to the target position by the cable car specifically includes: When the cable car lowers the loosening device to a preset distance from the target position, the lowering speed of the cable car is reduced to a preset speed; When the loosening device reaches the target position at the preset speed, the actual depth of the coupling is compared with the lowering length of the cable car, and the comparison result is corrected until the comparison result meets the preset range.

7. A control method according to any one of claims 5-6, characterized in that, The step of continuously shocking the coupling by the loosening device further includes: The cable car drives the loosening device to move to the male buckle matched with the coupling, and shocks the male buckle.

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