A magnetorheological fluid torque damper device and method for rotary steering

Abstract

This invention discloses a magnetorheological fluid torsional vibration damping device and method for rotary guidance, belonging to the field of drilling engineering technology. It includes a shell and a central shaft, with a damping cavity formed between the inner wall of the shell and the outer wall of the central shaft. The damping cavity is filled with magnetorheological fluid. An inertial damping unit is arranged within the damping cavity, comprising a gear bearing and an electromagnetic damping mechanism. The electromagnetic damping mechanism includes an electromagnetic coil, a magnetically conductive outer ring, and a magnetically conductive inner ring. An annular groove is provided on the outer wall of the shell opposite the gear bearing, into which the electromagnetic coil is embedded, and the magnetically conductive outer ring is fixed. The magnetically conductive inner ring is embedded on the inner wall of the central shaft opposite the gear bearing. An axis acceleration sensor and a gyroscope are mounted on the central shaft. This invention obtains the vibration intensity and viscosity-slip vibration index at the current sampling moment, changes the current in the electromagnetic coil in real time, and then adjusts the damping force of the inertial damping unit by adjusting the viscosity of the magnetorheological fluid.

Description

Technical Field

[0001] This invention belongs to the field of drilling engineering technology, specifically relating to a magnetorheological fluid torsional vibration damping device and method for rotary guidance. Background Technology

[0002] In oil and gas drilling, especially in complex well structures such as directional and horizontal wells, rotary steerable systems have become a core technology for achieving precise wellbore trajectory control. Rotary steerable systems contain numerous sophisticated electronic components, hydraulic control valves, and mechanical actuators. The movement of internal moving parts, as well as the continuous friction with the wellbore wall to provide lateral force, introduces additional, unstable torque loads, disrupting the relatively uniform torque transmission of traditional drill strings.

[0003] The stable operation of the rotary steerable system is crucial to the success of the entire drilling operation. However, rotary steerable systems are typically used when drilling into highly heterogeneous formations such as those with strong abrasiveness, hard interlayers, or alternating layers of hard and soft rock. When the drill bit breaks through the rock in these formations, the torque fluctuates dramatically. These fluctuations propagate upwards along the drill string as stress waves, and when coupled with the natural frequencies of the entire drill string system, they can easily be excited into strong torsional vibrations.

[0004] Existing torsional vibration dampers, including some viscous fluid-based dampers, are mostly passive vibration dampers. Their damping characteristics are fixed during manufacturing and cannot be adaptively adjusted according to the complex actual working conditions downhole. This can lead to unnecessary resistance during the smooth drilling phase, while insufficient damping may fail to provide the most effective protection during severe vibrations.

[0005] Therefore, there is an urgent need for a vibration reduction device and method that can sense the vibration state in real time and actively adjust the damping force. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a magnetorheological fluid torsional vibration damping device for rotary guidance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A magnetorheological fluid torsional vibration damping device for rotary guidance includes a housing and a central shaft rotatably fitted inside the housing, wherein a sealed damping cavity is formed between the inner wall of the housing and the outer wall of the central shaft. The vibration damping cavity is filled with magnetorheological fluid; The vibration damping cavity is provided with several inertial damping units arranged axially. Each inertial damping unit includes a gear bearing and an electromagnetic damping mechanism. The inner ring of the gear bearing is coaxially fixedly connected to the outer wall of the central shaft. The electromagnetic damping mechanism includes an electromagnetic coil, a magnetic outer ring, and a magnetic inner ring. An annular groove is provided on the outer wall of the outer casing, opposite the gear bearing. The electromagnetic coil is embedded in the corresponding annular groove, and the magnetic outer ring is fixed in the annular groove to cover the electromagnetic coil. A magnetic inner ring is embedded on the inner wall of the central shaft, opposite the gear bearing. The magnetic inner ring, gear bearing, and magnetic outer ring form a closed magnetic circuit. A three-axis accelerometer and a gyroscope are mounted on the central axis.

[0008] Preferably, an upper connector is coaxially fixedly connected to the inner side of the top of the outer shell, and an annular block is coaxially provided on the outer wall of the top of the central shaft, with the top of the annular block and the bottom of the upper connector being sealed together. An annular step is provided on the inner wall of the outer casing. The annular step is located at the lower end of the annular block. The outer wall of the central shaft is sealed to the inner wall of the outer casing below the annular step.

[0009] Preferably, a first sealing ring is provided between the top end of the annular block and the bottom end of the upper connector.

[0010] Preferably, a second sealing ring is provided between the outer wall surface of the central shaft and the inner wall surface of the outer casing below the annular step.

[0011] Preferably, three inertial damping units are arranged axially within the vibration damping cavity.

[0012] Preferably, one-way thrust ball bearings are provided between the uppermost gear bearing and the annular block, and between the lowermost gear bearing and the annular step; The shaft ring of the one-way thrust ball bearing is fixedly connected to the central shaft, and the seat ring of the one-way thrust ball bearing is coaxially fixedly connected to the inner wall surface of the housing. The race of the one-way thrust ball bearing abuts against the outer ring end face of the adjacent gear bearing.

[0013] Preferably, a double-direction thrust ball bearing is provided in the damping cavity between adjacent gear bearings, wherein the shaft ring of the double-direction thrust ball bearing is coaxially and fixedly connected to the outer wall surface of the central shaft, and the seat ring of the double-direction thrust ball bearing is coaxially and fixedly connected to the inner wall surface of the housing. The upper and lower ends of the shaft ring of the double-direction thrust ball bearing abut against the inner ring end face of the corresponding gear bearing.

[0014] The present invention also discloses a torsional vibration reduction method for rotary guides.

[0015] A torsional vibration damping method for rotary guides, implemented based on a torsional vibration damping device for rotary guides, includes the following steps: Step 1: Based on the two horizontally orthogonal linear acceleration values ​​measured by the triaxial accelerometer. and , This represents the sequence number of the sampling time. , The current sampling time number is used; the resultant acceleration perpendicular to the central axis is calculated. , for The square of, for The square of; Step 2, using Characterize the current number Vibration intensity at each sampling time, The calculation formula is as follows: when hour, , ; when hour, , ; in, It is the number of sampling points corresponding to the moving average window length; for The square of; Step 3, adopt the viscosity-slip ratio Characterize the current number Stick-slip vibration index at each sampling time, The calculation formula is as follows: ; when hour, Indicates that the serial number is located at The maximum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The minimum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The average angular velocity value at all sampling times within the range; when hour, Indicates that the serial number is located at The maximum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The minimum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The average angular velocity value at all sampling times within the range; Step 4, based on , The value determines the magnitude of the current in the electromagnetic coil.

[0016] Preferably, step 4 includes the following sub-steps: Step 41, when At that time, the current in the electromagnetic coil is adjusted to its maximum value; when Then proceed to step 42; Step 42, determine the current number Safety threshold at each sampling time The current number Danger threshold at each sampling time , ; when At that time, adjust the current in the electromagnetic coil to 0; when At that time, the current in the electromagnetic coil is adjusted to , This represents the maximum current in the electromagnetic coil; when At that time, the current in the electromagnetic coil is adjusted to its maximum value.

[0017] Preferably, the current number Safety threshold at each sampling time The current number Danger threshold at each sampling time The formula for determining it is as follows: ; ; in: The static reference threshold represents the minimum impact tolerance at low speeds. ; This is the maximum permissible eccentricity of the drill string. , The outer diameter of the tool; For the current number The angular velocity value at each sampling time. for The square of; For safety factors, the value ranges from 2.5 to 4.

[0018] The beneficial effects of this invention are: This invention obtains the vibration intensity and viscosity-slip vibration index at the current sampling moment, changes the current in the electromagnetic coil in real time, and then adjusts the damping force of the inertial damping unit by adjusting the viscosity of the magnetorheological fluid. That is, the damping force of the inertial damping unit is reduced during smooth drilling to achieve energy saving, and the damping force of the inertial damping unit is increased during severe vibration to protect downhole equipment. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0020] Figure 1 This is a schematic diagram of the structure of the magnetorheological fluid torsional vibration damping device for rotary guidance according to the present invention; Figure 2 yes Figure 1 Sectional view along axis AA; in: 1. Outer shell; 11. Annular step; 12. Second sealing ring; 13. Injection hole; 2. Central shaft; 21. Annular block; 22. First sealing ring; 3. Magnetorheological fluid; 4. Gear bearing; 5. Electromagnetic coil; 6. Magnetic outer ring; 7. Magnetic inner ring; 8. Upper connector; 9. One-way thrust ball bearing; 10. Two-way thrust ball bearing. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] In this invention, terms such as "upper," "lower," "bottom," and "top" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are merely relational terms determined for the convenience of describing the structural relationship of the various components or elements of this invention, and do not specifically refer to any component or element in this invention, and should not be construed as limiting this invention.

[0024] In this invention, terms such as "connected" and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Example 1: like Figures 1-2 As shown, a magnetorheological fluid torsional vibration damping device for rotary guidance includes a housing 1 and a central shaft 2 rotatably fitted inside the housing 1. Both the housing 1 and the central shaft 2 are axially continuous structures, and a closed vibration damping cavity is formed between the inner wall of the housing 1 and the outer wall of the central shaft 2. The vibration damping cavity is filled with magnetorheological fluid 3; The vibration damping cavity is provided with several inertial damping units arranged axially. Each inertial damping unit includes a gear bearing 4 and an electromagnetic damping mechanism. The inner ring of the gear bearing 4 is coaxially fixedly connected to the outer wall of the central shaft 2. The outer ring of the gear bearing 4 is not fixedly connected to the inner wall of the outer shell 1. There is a gap between the outer ring of the gear bearing 4 and the inner wall of the outer shell 1. The gear bearing 4 can rotate relative to the outer shell 1 within the vibration damping cavity. The electromagnetic damping mechanism includes an electromagnetic coil 5, a magnetic outer ring 6, and a magnetic inner ring 7. An annular groove is provided on the outer wall of the outer casing 1 at the position opposite to the gear bearing 4. The electromagnetic coil 5 is embedded in the corresponding annular groove, and the magnetic outer ring 6 is fixed in the annular groove to cover the electromagnetic coil 5. A magnetic inner ring 7 is embedded on the inner wall of the central shaft 2 at the position opposite to the gear bearing 4. The magnetic inner ring 7, the gear bearing 4, and the magnetic outer ring 6 form a closed magnetic circuit. A triaxial accelerometer and a gyroscope are mounted on the central axis 2. The triaxial accelerometer measures the linear acceleration values ​​in two orthogonal directions in the plane and the linear acceleration value along the axial direction. The linear acceleration values ​​in the two orthogonal directions in the plane are the linear acceleration values. and A gyroscope is used to measure angular acceleration.

[0027] Preferably, an upper connector 8 is coaxially fixedly connected to the inner side of the top end of the outer shell 1. Specifically, the outer shell 1 and the upper connector 8 are threaded together and sealed with a sealing ring. An annular block 21 is coaxially provided on the outer wall of the top end of the central shaft 2. The top end of the annular block 21 is sealed with the bottom end of the upper connector 8. The annular block 21 and the central shaft 2 are an integral structure. An annular step 11 is provided on the inner wall surface of the outer shell 1. The annular step 11 is located at the lower end of the annular block 21. The outer wall surface of the central shaft 2 and the inner wall surface of the outer shell 1 below the annular step 11 are sealed together.

[0028] Preferably, a first sealing ring 22 is provided between the top end of the annular block 21 and the bottom end of the upper connector 8.

[0029] Preferably, a second sealing ring 12 is provided between the outer wall surface of the central shaft 2 and the inner wall surface of the outer shell 1 below the annular step 11.

[0030] The sealing ring in this application is preferably made of high-temperature resistant fluororubber material.

[0031] Preferably, three inertial damping units are arranged axially within the vibration damping cavity.

[0032] Preferably, one-way thrust ball bearings 9 are provided between the uppermost gear bearing 4 and the annular block 21, and between the lowermost gear bearing 4 and the annular step 11. The shaft ring of the one-way thrust ball bearing 9 is fixedly connected to the central shaft 2, and the seat ring of the one-way thrust ball bearing 9 is coaxially fixedly connected to the inner wall surface of the outer shell 1. The seat ring of the one-way thrust ball bearing 9 abuts against the outer ring end face of the adjacent gear bearing 4.

[0033] Preferably, a double-direction thrust ball bearing 10 is provided in the damping cavity between adjacent gear bearings 4. The shaft ring of the double-direction thrust ball bearing 10 is coaxially and fixedly connected to the outer wall surface of the central shaft 2, and the seat ring of the double-direction thrust ball bearing 10 is coaxially and fixedly connected to the inner wall surface of the outer shell 1. The upper and lower ends of the shaft ring of the bidirectional thrust ball bearing 10 abut against the inner ring end face of the corresponding gear bearing 4.

[0034] Preferably, the outer shell 1 is provided with a liquid injection hole 13 that extends into the vibration damping cavity, which is used to evacuate the vibration damping cavity and inject magnetorheological fluid 3 after assembly to ensure that the cavity is completely filled and free of air bubbles. After the liquid injection is completed, the hole is blocked and sealed.

[0035] In this application, the lower end of the outer shell 1 is connected to a rotary steerable drill bit, the upper connector 8 is threadedly connected to the drill collar or drill rod above, so as to realize the continuity of the drill string and the transmission of torque, and the central shaft 2 is used to transmit axial drilling pressure.

[0036] Example 2: A torsional vibration damping method for rotary guides, implemented based on the torsional vibration damping device for rotary guides in Embodiment 1, includes the following steps: Step 1: Based on the two horizontally orthogonal linear acceleration values ​​measured by the triaxial accelerometer. and , This represents the sequence number of the sampling time. , The current sampling time number is used; calculate the resultant acceleration perpendicular to central axis 2. , for The square of, for The square of ; the resultant acceleration perpendicular to the central axis 2, which is related to the centripetal acceleration caused by eccentric rotation, and its fluctuation reflects torsional vibration; Step 2, using Characterize the current number Vibration intensity at each sampling time, The calculation formula is as follows: when hour, , ; when hour, , ; in, It is the number of sampling points corresponding to the moving average window length. The moving average window length is usually much larger than the drill string rotation period, but shorter than the typical time scale of rotation speed change caused by drilling operation. for The square of; Step 3, adopt the viscosity-slip ratio Characterize the current number Stick-slip vibration index at each sampling time, The calculation formula is as follows: ; when hour, Indicates that the serial number is located at The maximum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The minimum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The average angular velocity value at all sampling times within the range; when hour, Indicates that the serial number is located at The maximum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The minimum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The average angular velocity value at all sampling times within the range; Step 4, based on , Adjust the value to control the current in electromagnetic coil 5.

[0037] Preferably, step 4 includes the following sub-steps: Step 41, when When, adjust the current in electromagnetic coil 5 to its maximum value; when When stick-slip vibration is detected, the current in electromagnetic coil 5 is adjusted to its maximum value, electromagnetic coil 5 operates at full load, and the inertial damping unit provides the maximum damping force. when Then proceed to step 42; Step 42, determine the current number Safety threshold at each sampling time The current number Danger threshold at each sampling time , ; when When, adjust the current in electromagnetic coil 5 to 0; when When the working condition is stable, the electromagnetic coil 5 is de-energized, the magnetorheological fluid 3 maintains the fluid state, and the inertial damping unit provides basic low damping, resulting in high mechanical efficiency. when At that time, the current in electromagnetic coil 5 is adjusted to , This represents the maximum current in electromagnetic coil 5; when When, adjust the current in electromagnetic coil 5 to its maximum value; when When a severe vibration is detected, the current in electromagnetic coil 5 is adjusted to its maximum value, electromagnetic coil 5 operates at full load, and the inertial damping unit provides the maximum damping force.

[0038] The typical downhole current is 1.5A to 3A. The maximum current in the electromagnetic coil 5 in this application is... It is 2.5A.

[0039] When the vibration intensity at the current sampling moment exceeds the safety threshold, the electromagnetic coil 5 outputs a controllable current to generate a magnetic field. The generation of the magnetic field increases the apparent viscosity of the magnetorheological fluid 3 in the gap of the inertial damping unit by several orders of magnitude.

[0040] During normal, stable drilling, the gear bearing 4 is in a relatively stationary rotating state relative to the housing 1 and the central shaft 2. When the drill string encounters hard formations and experiences high-intensity torsional vibration, the housing 1 and the central shaft 2 undergo high-frequency motion. Due to inertia, the gear bearing 4 within the damping chamber maintains its original rotation speed and rotates relative to the housing 1 and the central shaft 2. The outer ring of the gear bearing 4 is subjected to intense shearing and agitation in the high-viscosity magnetorheological fluid 3. Under the influence of the high-intensity vibration, the magnetorheological fluid 3 increases its damping under the influence of the magnetic field generated by the current, suppressing this relative motion, stabilizing the drill string, and continuously converting the vibrational kinetic energy into heat energy. The generated heat is carried away by the circulating drilling fluid through the housing 1.

[0041] Preferably, the current number Safety threshold at each sampling time The current number Danger threshold at each sampling time The formula for determining it is as follows: ; ; in: This is the static baseline threshold, representing the minimum impact tolerance at low rotational speeds. Based on field measurements in oil drilling, when only the drilling mud is circulating without rotation, the lateral vibration of the drill string is typically within... ~ between, The vibration caused by gravitational acceleration is considered background "white noise," harmless to the tool and requiring no vibration damper. Since the sensor itself also has inherent noise, considering both the background noise from fluid excitation during mud pump startup and the sensor's measurement error margin, and to avoid false triggering under non-rotating conditions, the following approach is adopted: ; This is the maximum permissible eccentricity of the drill string. , The outer diameter of shell 1; For the current number The angular velocity value at each sampling time. for The square of; For safety, the value ranges from 2.5 to 4. Based on the principle of vibration energy dissipation, vibration energy is proportional to the square of the amplitude. When the real-time vibration amplitude reaches three times that of the normal eccentric condition, the vibration energy has increased to nine times that of the normal condition. Fluctuations in vibration energy are allowed within a certain range, but when the energy level jumps by nearly an order of magnitude, the system must be fully loaded to protect the precision electronic components. Therefore, it can be... The preferred value is 3, which serves as the critical point between the linear adjustment range and the saturated output range, ensuring both the smoothness of the adjustment and timely suppression of destructive shocks.

[0042] This invention obtains the vibration intensity and viscosity-slip vibration index at the current sampling moment, changes the current in the electromagnetic coil 5 in real time, and then adjusts the damping force of the inertial damping unit by adjusting the viscosity of the magnetorheological fluid. That is, the damping force of the inertial damping unit is reduced during smooth drilling to achieve energy saving, and the damping force of the inertial damping unit is increased during severe vibration to protect downhole equipment.

[0043] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, they are not intended to limit the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A magnetorheological fluid torque damping device for rotary steering, characterized in that, It includes an outer shell and a central shaft that is rotatably fitted inside the outer shell, and a sealed vibration damping cavity is formed between the inner wall surface of the outer shell and the outer wall surface of the central shaft; The vibration damping cavity is filled with magnetorheological fluid; The vibration damping cavity is provided with several inertial damping units arranged axially. Each inertial damping unit includes a gear bearing and an electromagnetic damping mechanism. The inner ring of the gear bearing is coaxially fixedly connected to the outer wall of the central shaft. The electromagnetic damping mechanism includes an electromagnetic coil, a magnetic outer ring, and a magnetic inner ring. An annular groove is provided on the outer wall of the outer casing, opposite the gear bearing. The electromagnetic coil is embedded in the corresponding annular groove, and the magnetic outer ring is fixed in the annular groove to cover the electromagnetic coil. A magnetic inner ring is embedded on the inner wall of the central shaft, opposite the gear bearing. The magnetic inner ring, gear bearing, and magnetic outer ring form a closed magnetic circuit. A three-axis accelerometer and a gyroscope are mounted on the central axis.

2. The magnetorheological fluid torque damping device for rotary steering of claim 1, wherein, An upper connector is coaxially fixed to the inner side of the top of the outer shell, and an annular block is coaxially provided on the outer wall of the top of the central shaft. The top of the annular block and the bottom of the upper connector are sealed together. An annular step is provided on the inner wall of the outer casing. The annular step is located at the lower end of the annular block. The outer wall of the central shaft is sealed to the inner wall of the outer casing below the annular step.

3. The magnetorheological fluid torque damping device for rotary steering of claim 2, wherein, A first sealing ring is provided between the top end of the annular block and the bottom end of the upper connector.

4. The magnetorheological fluid torque damping device for rotary steering of claim 2, wherein, A second sealing ring is provided between the outer wall surface of the central shaft and the inner wall surface of the outer casing below the annular step.

5. The magnetorheological fluid torque damping device for rotary steering of claim 1, wherein, Three inertial damping units are arranged axially within the vibration damping cavity.

6. The magnetorheological fluid torque damping device for rotary steering of claim 2, wherein, One-way thrust ball bearings are installed between the uppermost gear bearing and the annular block, and between the lowermost gear bearing and the annular step. The shaft ring of the one-way thrust ball bearing is fixedly connected to the central shaft, and the seat ring of the one-way thrust ball bearing is coaxially fixedly connected to the inner wall surface of the housing. The race of the one-way thrust ball bearing abuts against the outer ring end face of the adjacent gear bearing.

7. The magnetorheological fluid torque damping device for rotary steering of claim 1, wherein, A double-direction thrust ball bearing is installed in the vibration damping cavity between adjacent gear bearings. The shaft ring of the double-direction thrust ball bearing is coaxially and fixedly connected to the outer wall surface of the central shaft, and the seat ring of the double-direction thrust ball bearing is coaxially and fixedly connected to the inner wall surface of the housing. The upper and lower ends of the shaft ring of the double-direction thrust ball bearing abut against the inner ring end face of the corresponding gear bearing.

8. A method for torsional vibration damping of magnetorheological fluid for rotary guidance, implemented based on the magnetorheological fluid torsional vibration damping device for rotary guidance as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Based on the two horizontally orthogonal linear acceleration values ​​measured by the triaxial accelerometer. and , This represents the sequence number of the sampling time. , The current sampling time number is used; the resultant acceleration perpendicular to the central axis is calculated. , for The square of, for The square of; Step 2, using Characterize the current number Vibration intensity at each sampling time, The calculation formula is as follows: when hour, , ; when hour, , ; in, It is the number of sampling points corresponding to the moving average window length; for The square of; Step 3, adopt the viscosity-slip ratio Characterize the current number Stick-slip vibration index at each sampling time, The calculation formula is as follows: ; when hour, Indicates that the serial number is located at The maximum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The minimum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The average angular velocity value at all sampling times within the range; when hour, Indicates that the serial number is located at The maximum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The minimum angular velocity value among all sampling times within the range. Indicates that the serial number is located at The average angular velocity value at all sampling times within the range; Step 4, based on , The value determines the magnitude of the current in the electromagnetic coil.

9. The magnetorheological fluid torsional vibration reduction method for rotary guidance as described in claim 8, characterized in that, Step 4 includes the following sub-steps: Step 41, when At that time, the current in the electromagnetic coil is adjusted to its maximum value; when Then proceed to step 42; Step 42, determine the current number Safety threshold at each sampling time The current number Danger threshold at each sampling time , ; when At that time, adjust the current in the electromagnetic coil to 0; when At that time, the current in the electromagnetic coil is adjusted to , This represents the maximum current in the electromagnetic coil; when At that time, the current in the electromagnetic coil is adjusted to its maximum value.

10. The magnetorheological fluid torsional vibration reduction method for rotary guidance as described in claim 9, characterized in that, Current number Safety threshold at each sampling time The current number Danger threshold at each sampling time The formula for determining it is as follows: ； ； in: The static reference threshold represents the minimum impact tolerance at low speeds. ; This is the maximum permissible eccentricity of the drill string. , The outer diameter of the tool; For the current number The angular velocity value at each sampling time. for The square of; For safety factors, the value ranges from 2.5 to 4.

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