Soft torque control system, soft torque controller and control method for drilling machine

Abstract

The invention relates to a soft torque control system, a soft torque controller and a soft torque control method for a drilling machine, and the soft torque control system for the drilling machine comprises a frequency converter which controls the output torque and the output rotating speed of a motor; the programmable logic controller provides the motor set rotating speed and the motor set torque for the frequency converter so as to control the output torque and the output rotating speed of the motor according to the motor set rotating speed and the motor set torque; the soft torque controller is configured to obtain the actual rotating speed and the actual torque of the motor, the set parameters related to the motor and the physical parameters of the drill rod, and in the impedance control mode, the soft torque controller calculates the actual characteristic impedance of the drill rod according to the physical parameters of the drill rod and the actual torque and the actual rotating speed of the motor; calculating an impedance difference value between the actual characteristic impedance and the set characteristic impedance; the torque compensation amount is determined according to the impedance difference value, and the programmable logic controller receives the torque compensation amount from the soft torque controller and corrects the motor set torque according to the torque compensation amount.

Description

Technical Field

[0001] The present invention relates to the technical field of control of oil drilling equipment, in particular to a soft torque control system, a soft torque controller and a soft torque control method for a drilling rig, which are intended to suppress and eliminate stick-slip vibration of a drill pipe during drilling. Background Art

[0002] Drilling rigs are indispensable equipment in the exploration and production of oil and gas. The drilling rig uses the drill pipe to push the drill bit deep into the formation to complete the drilling task. However, during the drilling operation, the drill pipe system will be subjected to complex friction from the formation, which may cause the drill pipe system to experience the so-called "stick-slip vibration". Stick-slip vibration refers to the periodic "sticking" and "slipping" phenomenon of the drill pipe system during rotation due to the change in friction between the drill pipe and the formation during the drilling process. This vibration will significantly affect the efficiency and safety of drilling.

[0003] The mechanism of stick-slip vibration is complex, mainly related to the friction characteristics between the drill pipe system and the formation, the physical properties of the drill pipe material, and the dynamic working conditions of the drilling operation. During the drilling process, the friction between the drill bit and the drill pipe at the bottom of the drill pipe system will cause the drill pipe system to have sticking phenomenon when the stress changes. When the accumulated torque exceeds the friction force, the drill pipe system suddenly accelerates its rotation, that is, slip occurs. The repetition of this process leads to the stick-slip vibration of the drill pipe system.

[0004] The hazards of stick-slip vibration include but are not limited to: accelerating the mechanical wear of the drill bit and drill pipe system, resulting in breakage of the drill bit cutter and damage to the drill pipe; reducing the drilling rate and affecting drilling efficiency; shortening the life of the drill bit and increasing drilling costs; and in extreme cases, it may damage other key equipment downhole, such as the rotary steerable system and measurement while drilling (MWD) equipment, and even cause the downhole motor to stop working.

[0005] At present, the industry mainly suppresses stick-slip vibration through hardware improvement and optimization of software control strategy. Hardware improvement includes designing a drill pipe system with special friction characteristics, while software control strategy focuses on dynamically adjusting the torque and speed of the drill pipe system to achieve the purpose of suppressing vibration. However, existing solutions often face problems such as high algorithm complexity, difficult parameter adjustment, slow response speed, and high cost, which limits their application effect and popularity in actual drilling operations. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a new soft torque control system, soft torque controller and control method, which aims to respond quickly to reduce the stick-slip vibration of the drill pipe system through a simpler and more effective control algorithm, improve the safety and efficiency of drilling operations, and reduce the cost and complexity of the control system. The present invention is particularly suitable for real-time, accurate and rapid suppression of the stick-slip vibration of the drill pipe system under various drilling conditions and drilling rig types.

[0007] According to one aspect of an embodiment of the present application, a soft torque control system for a drilling rig is provided, the soft torque control system comprising: a frequency converter connected to a motor to control the output torque and output speed of the motor, the motor being connected to the drilling rig to drive a drill rod of the drilling rig; a programmable logic controller connected to the frequency converter and providing the frequency converter with a motor set speed and a motor set torque, the frequency converter controlling the output torque and output speed of the motor according to the motor set speed and the motor set torque; and a soft torque controller communicatively connected to the programmable logic controller, the soft torque controller being configured to obtain the actual speed and actual torque of the motor, set parameters related to the motor and physical parameters of the drill rod, the set parameters at least including set characteristics of the motor impedance, motor set torque and motor set speed, the physical parameters of the drill rod include at least the length, outer diameter, inner diameter, density and shear modulus of the drill rod, wherein the soft torque control system can operate in impedance control mode, and in impedance control mode, the soft torque controller is configured to: calculate the actual characteristic impedance of the drill rod according to the physical parameters of the drill rod and the actual torque and actual speed of the motor; calculate the impedance difference between the actual characteristic impedance and the set characteristic impedance; and determine the torque compensation amount according to the impedance difference, wherein the programmable logic controller receives the torque compensation amount from the soft torque controller, corrects the motor set torque according to the torque compensation amount, and transmits the corrected motor set torque to the inverter.

[0008] In this way, the designed soft torque controller can calculate the actual characteristic impedance of the drill pipe according to the physical parameters of the drill pipe (such as length, outer diameter, inner diameter, density and shear modulus) and the real-time operating status of the motor (including actual speed and actual torque), and compare it with the preset characteristic impedance to determine the impedance difference, and then calculate the torque compensation amount. This enables the system to adjust the output torque of the motor according to the characteristic impedance to compensate for the dynamic changes in the drill pipe system when stick-slip vibration is detected, thereby achieving real-time, accurate and rapid suppression of stick-slip vibration of the drill pipe.

[0009] In an embodiment of the present application, the soft torque control system can also operate in a speed control mode and can switch between an impedance control mode and a speed control mode. In the speed control mode, the programmable logic controller is configured to: determine the speed compensation amount according to the motor set speed and the actual speed of the motor, and correct the motor set speed according to the speed compensation amount, and transmit the corrected motor set speed to the frequency converter.

[0010] In an embodiment of the present application, the soft torque control system is also capable of operating in a torque control mode and is capable of switching between an impedance control mode, a torque control mode and a speed control mode. In the torque control mode, the programmable logic controller is configured to determine a torque compensation amount based on the actual torque of the motor and the set torque of the motor and to correct the set torque of the motor based on the torque compensation amount, and to transmit the corrected set torque of the motor to the frequency converter.

[0011] In this way, the soft torque control system can suppress stick-slip vibration in multiple control modes, significantly enhancing its flexibility and effectiveness in drilling operations. By switching between impedance control mode, speed control mode and torque control mode, the soft torque control system can dynamically adjust the control strategy according to the specific needs of the drilling process.

[0012] In an embodiment of the present application, the soft torque controller includes: a data acquisition unit, configured to acquire the actual speed and actual torque of the motor, set parameters related to the motor and physical parameters of the drill rod, the set parameters at least include the set characteristic impedance of the motor, and the physical parameters of the drill rod at least include the length, outer diameter, inner diameter, density and shear modulus of the drill rod; a first control unit, configured to calculate the actual characteristic impedance of the drill rod based on the physical parameters of the drill rod and the actual torque and actual speed of the motor; and a second control unit, configured to calculate the impedance difference between the actual characteristic impedance and the set characteristic impedance; and determine the torque compensation amount based on the impedance difference.

[0013] In this way, the computational burden of a single control unit can be reduced, the control accuracy and response speed of the system can be improved, and the flexibility, reliability, performance and scalability of the system can be improved.

[0014] In an embodiment of the present application, the data acquisition unit includes: a first filter, used to receive a pulse signal indicating the rotational speed of the motor from a motor sensor and filter out a first frequency band of the pulse signal to generate a first filtered signal; a second filter, used to receive the first filtered signal from the first filter and filter out a second frequency band of the first filtered signal to generate a second filtered signal, the second frequency band being different from the first frequency band; and a calculation unit, used to receive the second filtered signal from the second filter and calculate the actual rotational speed of the motor based on the second filtered signal, and calculate the actual torque of the motor based on the actual rotational speed of the motor.

[0015] In this way, by adopting double-stage filtering, the interference frequency band in the motor sensor signal is effectively eliminated, ensuring the purity and reliability of the speed signal. This signal preprocessing mechanism not only improves the accuracy of the actual motor speed calculation, but also indirectly improves the accuracy of the actual torque calculation, providing a solid foundation for subsequent impedance calculations. By precisely controlling and eliminating noise in specific frequency bands, the soft torque controller can more accurately monitor the actual operating status of the motor during drilling operations, enhance the system's sensitivity and response speed to stick-slip vibration suppression, ensure the smooth operation of the drilling process, reduce equipment failures and maintenance costs, and improve the overall efficiency and safety of drilling operations.

[0016] In an embodiment of the present application, the data acquisition unit acquires the actual speed and the actual torque of the motor from the programmable logic controller.

[0017] In this way, the data acquisition unit can directly obtain from the programmable logic controller the actual rotational speed and actual torque that have been sampled and calculated by the programmable logic controller, thereby reducing the configuration of the data acquisition unit, that is, there is no need to set up a calculation unit.

[0018] In an embodiment of the present application, the second control unit includes: a first operating unit, used to calculate the difference between the set characteristic impedance and the actual characteristic impedance to generate an impedance difference; and a processing unit, connected to the first operating unit, the processing unit receiving the impedance difference from the first operating unit; wherein, in the impedance control mode, the processing unit calculates the torque compensation amount according to the impedance difference and transmits the calculated torque compensation amount to the programmable logic controller.

[0019] According to another embodiment of the present application, a soft torque controller for a drilling rig is provided. The drilling rig is connected to a motor, and the motor is used to drive a drill rod of the drilling rig. The soft torque controller includes: a data acquisition unit, configured to acquire an actual rotational speed and an actual torque of the motor, set parameters related to the motor, and physical parameters of the drill rod, the set parameters at least include a set characteristic impedance of the motor, and the physical parameters of the drill rod include at least the length, outer diameter, inner diameter, density of the drill rod, and shear modulus of the drill rod; a control unit, configured to calculate an actual characteristic impedance of the drill rod based on the physical parameters of the drill rod and the actual torque and actual rotational speed of the motor; calculate the impedance difference between the actual characteristic impedance and the set characteristic impedance; and determine a torque compensation amount based on the impedance difference.

[0020] In another embodiment of the present application, the control unit includes: a first control unit, configured to calculate the actual characteristic impedance of the drill rod based on the physical parameters of the drill rod and the actual torque and actual speed of the motor; and a second control unit, configured to calculate the impedance difference between the actual characteristic impedance and the set characteristic impedance; and determine the torque compensation amount based on the impedance difference.

[0021] In another embodiment of the present application, the data acquisition unit includes: a first filter, used to receive a pulse signal indicating the rotational speed of the motor from a motor sensor and filter out a first frequency band of the pulse signal to generate a first filtered signal; a second filter, used to receive the first filtered signal from the first filter and filter out a second frequency band of the first filtered signal to generate a second filtered signal, the second frequency band being different from the first frequency band; and a calculation unit, used to receive the second filtered signal from the second filter and calculate the actual rotational speed of the motor based on the second filtered signal, and calculate the actual torque of the motor based on the actual rotational speed of the motor.

[0022] In another embodiment of the present application, the second control unit includes: a first operating unit, used to calculate the difference between the set characteristic impedance and the actual characteristic impedance to generate an impedance difference; and a processing unit, connected to the first operating unit to receive the impedance difference from the first operating unit, and calculate the torque compensation amount based on the impedance difference.

[0023] According to another embodiment of the present application, a soft torque control method for a drilling rig is provided, wherein the drilling rig is connected to a motor, and the motor is used to drive a drill rod of the drilling rig, and the soft torque control method includes: obtaining an actual rotational speed and an actual torque of the motor, setting parameters related to the motor, and physical parameters of the drill rod, wherein the setting parameters include at least a set characteristic impedance of the motor, a set rotational speed of the motor, and a set torque of the motor, and the physical parameters of the drill rod include at least a length, an outer diameter, an inner diameter, a density of the drill rod, and a shear modulus of the drill rod. When the motor is controlled in an impedance control mode, the soft torque control method also includes: calculating an actual characteristic impedance of the drill rod based on the physical parameters of the drill rod and the actual torque and actual rotational speed of the motor; calculating an impedance difference between the actual characteristic impedance and the set characteristic impedance; determining a torque compensation amount based on the impedance difference; and correcting the motor set torque based on the torque compensation amount.

[0024] In another embodiment of the present application, when controlling the motor in the speed control mode, the soft torque control method further includes: determining the speed compensation amount according to the motor set speed and the actual speed of the motor; and correcting the motor set speed according to the speed compensation amount.

[0025] In another embodiment of the present application, when controlling the motor in the torque control mode, the soft torque control method further includes: determining the torque compensation amount according to the actual torque of the motor and the set torque of the motor.

[0026] According to another embodiment of the present application, a computer-readable storage medium is provided, storing instructions, which, when executed by a processor, enable the processor to execute the above-mentioned soft torque control method.

[0027] In the present application, the amplitude of stick-slip vibration can be reduced quickly and effectively or the stick-slip vibration can be eliminated, the fatigue damage degree of the drill pipe is reduced, and the probability of downhole accidents due to drill pipe fatigue is reduced; it has the advantages of enabling the drill bit to quickly move away from the stick-slip vibration area, increasing the drilling speed, reducing drilling costs and improving drilling efficiency. In addition, the present application can use more compact and simple calculations and parameters that are easier for drilling operators to input. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0029] Figure 1 A block diagram of a soft torque control system for a drilling rig according to an embodiment of the present application is shown.

[0030] Figure 2 Shows Figure 1 Block diagram of the specific structure of the soft torque controller in the soft torque control system.

[0031] Figure 3 A flow chart of a soft torque control method according to another embodiment of the present application is shown.

[0032] Figure 4 A graph showing the measured torque and measured rotational speed of the motor when the drill pipe exhibits stick-slip vibration phenomenon.

[0033] Description of Figure Numbers:

[0034] 100 soft torque control system

[0035] 10. Frequency converter;

[0036] 20 motors;

[0037] 30 Programmable logic controller;

[0038] 40 Soft torque controller;

[0039] 41 data acquisition unit;

[0040] 410 first filter;

[0041] 411 second filter;

[0042] 412 computing unit;

[0043] 42 first control unit;

[0044] 43 second control unit;

[0045] 431 first operation unit;

[0046] 432 Processing Unit;

[0047] 50 Motor sensor. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0049] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the signals used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0050] As discussed in the previous background technology, the industry's suppression of stick-slip vibration faces problems such as high algorithm complexity, difficult parameter adjustment, high cost, and slow response speed, which limits its application effect and popularity in actual drilling operations.

[0051] To this end, the concept of the present invention is to design a soft torque controller, which can calculate the actual characteristic impedance of the drill pipe according to the physical parameters of the drill pipe (such as length, outer diameter, inner diameter, density and shear modulus) and the real-time operating status of the motor (including actual speed and actual torque), and compare it with the preset characteristic impedance to determine the impedance difference, and then calculate the torque compensation amount. This enables the system to adjust the output torque of the motor according to the characteristic impedance to compensate for the dynamic changes in the drill pipe system when stick-slip vibration is detected, thereby achieving real-time, accurate and rapid suppression of stick-slip vibration of the drill pipe.

[0052] Figure 1 FIG. 1 is a block diagram of a soft torque control system for a drilling rig according to an embodiment of the present application. Figure 1As shown, the soft torque control system 100 may include: a frequency converter 10, connected to a motor 20 to control the output torque and output speed of the motor 20, wherein the motor 20 is connected to a drilling rig to drive a drill rod of the drilling rig; a programmable logic controller 30, connected to the frequency converter 10 and providing the frequency converter 10 with a motor set speed ω s and motor set torque T s , the inverter 10 sets the speed according to the motor s and motor set torque T s and a soft torque controller 40, which is communicatively connected to the programmable logic controller 30, and the soft torque controller 40 is configured to obtain the actual speed of the motor 20 ω a and the actual torque T a , setting parameters related to the motor 20 and physical parameters of the drill pipe, the setting parameters may at least include the setting characteristic impedance T of the motor 20 s , motor set torque T s and motor set speed ω s The physical parameters of the drill pipe may include at least the length, outer diameter, inner diameter, density and shear modulus of the drill pipe.

[0053] In this embodiment, if Figure 1 As shown, the motor 20 may be electrically connected to an encoder 50, which is used to collect a pulse signal indicating the actual speed of the motor, and provide the collected pulse signal to the inverter 10 and / or the soft torque controller 40. The inverter 10 may determine the actual speed according to the pulse signal indicating the actual speed, calculate the actual torque of the motor 20 according to the actual speed, and transmit the actual speed and the actual torque to the programmable logic controller 30. Alternatively or additionally, the soft torque controller 40 may determine the actual speed of the motor according to the pulse signal indicating the actual speed, and calculate the actual torque of the motor 10 according to the actual speed, as described in detail below.

[0054] As an example, the soft torque controller 40 can also be configured to obtain a change trend of the motor torque according to the actual torque of the motor, and obtain a curve of the motor torque, such as Figure 4 As shown. The soft torque controller 40 can also be configured to determine whether the drill rod has a stick-slip phenomenon based on the curve of the motor torque; when the curve of the motor torque is sawtooth-shaped, it means that the drill rod may have a stick-slip phenomenon. At this time, the soft torque controller 40 is configured to adjust the drilling speed of the drill bit to suppress stick-slip vibration. Alternatively, the soft torque controller 40 can also be configured to obtain the change trend of the motor speed and obtain the curve of the motor speed, such as Figure 4The soft torque controller 40 can also be configured to determine whether the drill rod has a stick-slip phenomenon according to the curve of the motor speed; when the curve of the motor speed is sawtooth-shaped, it indicates that the drill rod may have a stick-slip phenomenon.

[0055] When the soft torque controller 40 determines that the drill rod may have a stick-slip phenomenon, the soft torque control system 100 can suppress the stick-slip vibration of the drill rod by the soft torque controller 40 in an impedance control manner. Specifically, the soft torque controller 40 can be configured to: a and the actual speed ω a Calculate the actual characteristic impedance of the drill pipe; calculate the actual characteristic impedance and set the characteristic impedance Z s and determining the torque compensation amount T according to the impedance difference. c The programmable logic controller 30 receives the torque compensation value T from the soft torque controller 40. c , and according to the torque compensation amount T c Correction motor set torque T s and transmits the corrected motor set torque to the inverter 10.

[0056] Specifically, the soft torque controller 40 can be configured to generate a torque signal according to the actual torque T of the motor. a and the actual speed ω a , calculate the dynamic torque of the drill pipe, and use the finite element method or the equivalent network analysis method to discretize the drill pipe into multiple units, calculate the dynamic response of each unit to establish the dynamic model of the drill pipe; through the dynamic model of the drill pipe, combined with the physical parameters of the drill pipe (such as length, outer diameter, inner diameter, wall thickness, material properties (material density), and shear modulus of the drill pipe), calculate the equivalent characteristic impedance of the drill pipe as the actual characteristic impedance of the drill pipe.

[0057] In addition, the drill pipe’s characteristic impedance Z s According to the formula Calculate, where Z is the set characteristic impedance of the drill pipe and Jp is the moment of inertia of the drill pipe: ρ is the density of drill pipe, G is the shear modulus of drill pipe, R iout is the outer diameter of the drill pipe section i (i-th unit), R iint is the inner diameter of the drill pipe section i.

[0058] Furthermore, the soft torque controller 40 can establish a proportional relationship between the change in characteristic impedance and the change in torque according to the dynamic model of the motor, and can establish a mapping relationship between the impedance difference and the torque offset through experiments or simulations. The soft torque controller 40 can query the mapping relationship between the impedance difference and the torque offset in the process of determining the torque compensation amount according to the impedance difference and determine the torque compensation amount T according to the mapping relationship. c .

[0059] Alternatively, the soft torque controller 40 can establish a data model of the change in characteristic impedance and torque change based on the dynamic model of the motor. The soft torque controller 40 can determine the torque compensation amount T according to the impedance difference using a mathematical model. c .

[0060] As an example, the soft torque control system 100 can also operate in a speed control mode and can switch between the impedance control mode and the speed control mode. In the speed control mode, the soft torque control system 100 is controlled by the programmable logic controller 30. The programmable logic controller 30 can be configured to: set the speed ω according to the motor s and the actual speed ω of the motor 20 a Determine the speed compensation amount and correct the motor set speed ω according to the speed compensation amount s , and transmit the corrected motor set speed to the inverter 10. Preferably, the actual speed ω a Filtering is performed to remove noise.

[0061] As an example, the soft torque control system 100 can also operate in a torque control mode and can switch between an impedance control mode, a torque control mode, and a speed control mode. In the torque control mode, the soft torque control system 100 is controlled by the programmable logic controller 30. The programmable logic controller 30 can be configured to control the motor 20 according to the actual torque T a With the motor set torque T s Determine the torque compensation amount and correct the motor set torque T according to the torque compensation amount s and transmits the corrected motor set torque to the inverter 10.

[0062] It can be understood that the inverter 10 may include a PI controller (not shown), and the PI controller may adjust Kp and Ki coefficients of the PI controller according to the corrected motor set torque and the corrected motor set speed, thereby controlling the motor.

[0063] The soft torque control system of the present application can operate in three control modes to suppress stick-slip vibration, significantly enhancing its flexibility and effectiveness in drilling operations. By switching between impedance control mode, speed control mode and torque control mode, the soft torque controller can dynamically adjust the control strategy according to the specific needs of the drilling process.

[0064] In particular, since the characteristic impedance of the drill pipe refers to the characteristic parameter of the energy transfer and dynamic response of the drill pipe during the vibration process, it is used to analyze the torsional vibration and longitudinal vibration characteristics of the drill pipe, and can reflect the energy transfer efficiency and vibration characteristics of the drill pipe system under dynamic load. Therefore, by designing a soft torque controller to control the stick-slip vibration suppression in a characteristic impedance control manner, it is possible to respond quickly to the stick-slip vibration phenomenon, thereby quickly and accurately solving the stick-slip vibration problem.

[0065] Further, Figure 2 Shows Figure 1 The block diagram of the specific structure of the soft torque controller 40 in the soft torque control system of FIG. Figure 2 As shown, the soft torque controller 40 may include: a data acquisition unit 41, configured to acquire the actual speed and actual torque of the motor 20, setting parameters related to the motor 20 and physical parameters of the drill rod, the setting parameters at least include the set characteristic impedance Zs of the motor, and the physical parameters of the drill rod at least include the length, outer diameter, inner diameter, density and shear modulus of the drill rod; a first control unit 42 is configured to calculate the actual characteristic impedance of the drill rod according to the physical parameters of the drill rod and the actual torque and actual speed of the motor 20; and a second control unit 43 is configured to calculate the impedance difference between the actual characteristic impedance and the set characteristic impedance; and determine the torque compensation amount T according to the impedance difference c , and the torque compensation amount T c is transmitted to the programmable logic controller 30 so that the programmable logic controller 30 can calculate the torque compensation value T according to the torque compensation value T c Correction motor set torque T s and transmits the corrected motor set torque to the inverter 10.

[0066] As an example, the data acquisition unit 41 may include: a first filter 410, used to receive a pulse signal indicating the rotational speed of the motor 20 from the motor sensor 50 and filter out the first frequency band of the pulse signal to generate a first filtered signal; a second filter 411, used to receive the first filtered signal from the first filter 410 and filter out the second frequency band of the first filtered signal to generate a second filtered signal, the second frequency band being different from the first frequency band; and a calculation unit 412, used to receive the second filtered signal from the second filter 411 and calculate the actual rotational speed of the motor 20 based on the second filtered signal, and calculate the actual torque of the motor 20 based on the actual rotational speed of the motor 20.

[0067] In this article, the motor sensor 50 can be an encoder, which collects pulse signals of the motor speed. Alternatively, the motor sensor 50 can include a speed sensor and a torque sensor. The torque sensor can be installed on the power cable of the motor to detect the actual torque of the motor; the speed sensor can be installed on the motor shaft to collect the actual speed of the motor. Other ways to obtain the actual speed and actual torque of the motor are also within the scope of the requirements of this application. In this case, the data acquisition unit 41 can directly obtain the actual speed and actual torque of the motor from the motor sensor 50, so that components such as filters and calculation units can be omitted.

[0068] In addition, the data acquisition unit 41 may receive physical parameters of the drill rod input by a user from the outside. For example, the user may input various physical parameters of the drill rod through a touch screen.

[0069] In this paper, due to the use of double-stage filtering, the interference frequency band in the motor sensor signal is effectively eliminated, ensuring the reliability of the speed signal, thereby improving the accuracy of the actual motor speed calculation and indirectly improving the accuracy of the actual torque calculation.

[0070] As an alternative embodiment, the data acquisition unit 41 may be connected to the programmable logic controller 30 and receive the actual speed ω of the motor 20 from the programmable logic controller 30. a and the actual torque T a .

[0071] In other words, the data acquisition unit 41 can directly obtain the actual speed and actual torque that have been sampled and calculated by the programmable logic controller 30 from the programmable logic controller 30, thereby reducing the amount of calculation of the data acquisition unit 41, and the filter unit can be omitted to simplify the configuration of the data acquisition unit 41.

[0072] The second control unit 43 may include: a first operation unit 431, for calculating the difference between the set characteristic impedance and the actual characteristic impedance to generate an impedance difference; and a processing unit 432, connected to the first operation unit 431 and receiving the impedance difference from the first operation unit 431, wherein in the impedance control mode, the processing unit 432 calculates the torque compensation amount according to the impedance difference and transmits the calculated torque compensation amount to the programmable logic controller 30. In this article, the first operation unit 431 can be implemented as an arithmetic operation unit, including but not limited to an adder, a subtractor, etc.

[0073] The above is a detailed description of the soft torque control system and soft torque controller of the present application. In the soft torque control system of the present application, the output torque of the motor can be controlled by characteristic impedance, and the accumulated torque can be quickly released, so as to avoid the sudden acceleration of the drill rod system and stabilize the torque of the drill rod, effectively protect the drill rod and extend the service life of the drill rod, and prevent the drill bit speed from fluctuating greatly, so as to effectively protect the drill bit and extend the service life of the drill bit.

[0074] Figure 3 A flow chart of a soft torque control method for a drilling rig is shown, as Figure 3 As shown, the soft torque control method includes:

[0075] S301, obtaining the actual speed and actual torque of the motor 20, setting parameters related to the motor 20 and physical parameters of the drill rod, wherein the setting parameters at least include the set characteristic impedance of the motor 20, the motor set torque and the motor set speed, and the physical parameters of the drill rod at least include the length, outer diameter, inner diameter, density and shear modulus of the drill rod,

[0076] When controlling the motor in impedance control mode, the soft torque control method also includes: S302, calculating the actual characteristic impedance of the drill rod based on the physical parameters of the drill rod and the actual torque and actual speed of the motor 20; calculating the impedance difference between the actual characteristic impedance and the set characteristic impedance; determining the torque compensation amount based on the impedance difference; and correcting the motor set torque based on the torque compensation amount.

[0077] When the motor is controlled in the speed control mode, the soft torque control method further includes: S303, determining a speed compensation amount according to the motor set speed and the actual speed of the motor 20, and correcting the motor set speed according to the speed compensation amount.

[0078] When the motor is controlled in the torque control mode, the soft torque control method further includes: S304, determining a torque compensation amount according to the actual torque of the motor 20 and the motor set torque.

[0079] The present application can also be implemented in the form of a computer-readable storage medium, wherein the computer-readable storage medium stores instructions, and when the instructions are executed by a processor, the processor executes the above-mentioned soft torque control method, which will not be described in detail here.

[0080] The technical solution provided by this application can have at least the following technical effects:

[0081] 1) It can effectively avoid the stick-slip phenomenon of the drill bit, thereby reducing the occurrence of drill jumping and drill sticking, thereby improving the drilling quality and efficiency, and has significant economic benefits for the oil drilling industry.

[0082] 2) The system provided in the present application can be controlled by a soft torque controller to suppress stick-slip vibration, greatly reducing the labor intensity of workers.

[0083] 3) The system provided in the present application uses characteristic impedance to control the output torque of the motor, which can quickly release the accumulated torque, avoid sudden acceleration of the drill rod system and make the torque of the drill rod tend to be stable, effectively protect the drill rod and extend the service life of the drill rod, and can prevent the drill bit speed from fluctuating drastically, which can effectively protect the drill bit and extend the service life of the drill bit.

[0084] 4) The system provided in this application adds a soft torque controller on the basis of the original drilling rig control system. The soft torque controller can be an independent control system that can participate in control and exit control in a simple operation manner, and exiting control will not have any impact on the original control system of the drilling rig. Therefore, the soft torque controller can be used in various types of drilling rig control systems.

[0085] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0086] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic, such as the division of units or units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of units or units can be electrical or other forms.

[0087] The units or elements described as separate components may or may not be physically separated, and the components shown as units or elements may or may not be physical units or elements, that is, they may be located in one place, or they may be distributed on multiple network units or elements. Some or all of the units or elements may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0088] In addition, each functional unit or unit in each embodiment of the present application may be integrated into a processing unit 432 or unit, or each unit or unit may exist physically separately, or two or more units or units may be integrated into one unit or unit. The above-mentioned integrated unit or unit may be implemented in the form of hardware or in the form of software functional unit or unit.

[0089] The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A soft torque control system for a drilling rig, characterized in that: The soft torque control system comprises: A frequency converter (10) connected to a motor (20) to control an output torque and an output speed of the motor (20), wherein the motor (20) is connected to the drilling rig to drive a drill rod of the drilling rig; a programmable logic controller (30) connected to the frequency converter (10) and providing the frequency converter (10) with a motor set speed and a motor set torque, wherein the frequency converter (10) controls the output torque and the output speed of the motor (20) according to the motor set speed and the motor set torque; and a soft torque controller (40) communicatively connected to the programmable logic controller (30), the soft torque controller (40) being configured to obtain an actual rotational speed and an actual torque of the motor (20), setting parameters associated with the motor (20) and physical parameters of the drill rod, the setting parameters at least comprising a set characteristic impedance of the motor (20), a set torque of the motor and a set rotational speed of the motor, and the physical parameters of the drill rod at least comprising a length, an outer diameter, an inner diameter, a density of the drill rod and a shear modulus of the drill rod, The soft torque control system is capable of operating in an impedance control mode, in which the soft torque controller (40) is configured as follows: Calculating the actual characteristic impedance of the drill rod according to the physical parameters of the drill rod and the actual torque and the actual rotation speed of the motor (20); calculating an impedance difference between the actual characteristic impedance and the set characteristic impedance; and Determine the torque compensation amount according to the impedance difference, The programmable logic controller (30) receives the torque compensation amount from the soft torque controller (40), corrects the motor set torque according to the torque compensation amount, and transmits the corrected motor set torque to the frequency converter (10).

2. The soft torque control system for a drilling rig according to claim 1, characterized in that: The soft torque control system is also capable of operating in a speed control mode and is capable of switching between the impedance control mode and the speed control mode. In the speed control mode, the programmable logic controller (30) is configured to: determine a speed compensation amount according to the motor set speed and the actual speed of the motor (20), correct the motor set speed according to the speed compensation amount, and transmit the corrected motor set speed to the frequency converter (10).

3. The soft torque control system for a drilling rig according to claim 2, characterized in that: The soft torque control system is also capable of operating in a torque control mode and is capable of switching between the impedance control mode, the torque control mode and the speed control mode. In the torque control mode, the programmable logic controller (30) is configured to determine a torque compensation amount according to an actual torque of the motor (20) and the motor set torque, correct the motor set torque according to the torque compensation amount, and transmit the corrected motor set torque to the inverter (10).

4. The soft torque control system for a drilling rig according to claim 3, characterized in that: The soft torque controller (40) comprises: A data acquisition unit (41) is configured to acquire the actual rotation speed and actual torque of the motor, setting parameters related to the motor and physical parameters of the drill pipe, a first control unit (42) configured to calculate the actual characteristic impedance of the drill rod according to the physical parameters of the drill rod and the actual torque and the actual rotation speed of the motor; and The second control unit (43) is configured to calculate the impedance difference between the actual characteristic impedance and the set characteristic impedance; and determine the torque compensation amount according to the impedance difference.

5. The soft torque control system for a drilling rig according to claim 4, characterized in that: The data acquisition unit (41) comprises: A first filter (410) is used to receive a pulse signal indicating the rotation speed of the motor (20) from a motor sensor (50) and filter out a first frequency band of the pulse signal to generate a first filtered signal; a second filter (411) for receiving the first filtered signal from the first filter (410) and filtering out a second frequency band of the first filtered signal to generate a second filtered signal, the second frequency band being different from the first frequency band; and A calculation unit (412) is used to receive the second filter signal from the second filter (411) and calculate the actual speed of the motor according to the second filter signal, and calculate the actual torque of the motor according to the actual speed of the motor.

6. The soft torque control system for a drilling rig according to claim 4, characterized in that: The data acquisition unit (41) receives the actual rotation speed and the actual torque of the motor from the programmable logic controller.

7. The soft torque control system for a drilling rig according to claim 4, characterized in that: The second control unit (43) comprises: A first operation unit (431) is used to calculate the difference between the set characteristic impedance and the actual characteristic impedance to generate an impedance difference; and A processing unit (432), connected to the first operation unit (431), wherein the processing unit (432) receives the impedance difference from the first operation unit (431); Wherein, in the impedance control mode, the processing unit (432) calculates the torque compensation amount according to the impedance difference and transmits the calculated torque compensation amount to the programmable logic controller (30).

8. A soft torque controller for a drilling rig, characterized in that: The drilling rig is connected to a motor (20), the motor (20) is used to drive a drill rod of the drilling rig, and the soft torque controller is configured as follows: A data acquisition unit (41) is configured to acquire an actual rotation speed and an actual torque of the motor, setting parameters related to the motor, and physical parameters of the drill rod, wherein the setting parameters at least include a setting characteristic impedance of the motor, and the physical parameters of the drill rod at least include a length, an outer diameter, an inner diameter, a density of the drill rod, and a shear modulus of the drill rod. A control unit configured to calculate an actual characteristic impedance of the drill rod according to physical parameters of the drill rod and the actual torque and the actual rotation speed of the motor; Calculating an impedance difference between the actual characteristic impedance and the set characteristic impedance; And determining the torque compensation amount according to the impedance difference.

9. The soft torque controller according to claim 8, characterized in that: The control unit comprises: a first control unit (42) configured to calculate the actual characteristic impedance of the drill rod according to the physical parameters of the drill rod and the actual torque and the actual rotation speed of the motor; and The second control unit (43) is configured to calculate an impedance difference between the actual characteristic impedance and the set characteristic impedance; and determine a torque compensation amount according to the impedance difference.

10. The soft torque controller according to claim 8, characterized in that: The data acquisition unit (41) comprises: A first filter (410) is used to receive a pulse signal indicating the rotation speed of the motor from a motor sensor (50) and filter out a first frequency band of the pulse signal to generate a first filtered signal; a second filter (411) for receiving the first filtered signal from the first filter (410) and filtering out a second frequency band of the first filtered signal to generate a second filtered signal, the second frequency band being different from the first frequency band; and A calculation unit (412) is used to receive the second filter signal from the second filter (411) and calculate the actual speed of the motor according to the second filter signal, and calculate the actual torque of the motor according to the actual speed of the motor.

11. The soft torque controller according to claim 9, characterized in that: The second control unit (43) comprises: A first operation unit (431) is used to calculate the difference between the set characteristic impedance and the actual characteristic impedance to generate an impedance difference; and A processing unit (432) is connected to the first operation unit (431) to receive the impedance difference from the first operation unit (431) and calculate the torque compensation amount according to the impedance difference.

12. A soft torque control method for a drilling rig, the drilling rig being connected to a motor, the motor being used to drive a drill rod of the drilling rig, characterized in that: The soft torque control method comprises: acquiring an actual speed and an actual torque of the motor, setting parameters related to the motor, and physical parameters of the drill rod, wherein the setting parameters at least include a set characteristic impedance of the motor, a set speed of the motor, and a set torque of the motor, and the physical parameters of the drill rod at least include a length, an outer diameter, an inner diameter, a density of the drill rod, and a shear modulus of the drill rod, When the motor is controlled in impedance control mode, the soft torque control method further includes: Calculating the actual characteristic impedance of the drill rod according to the physical parameters of the drill rod and the actual torque and the actual rotation speed of the motor; Calculating an impedance difference between the actual characteristic impedance and the set characteristic impedance; Determining a torque compensation amount according to the impedance difference; and The motor set torque is corrected according to the torque compensation amount.

13. The soft torque control method according to claim 12, characterized in that: When the motor is controlled in a speed control mode, the soft torque control method further includes: Determining a speed compensation amount according to the motor set speed and the motor actual speed; and The motor set speed is corrected according to the speed compensation amount.

14. The soft torque control method according to claim 12, characterized in that: When the motor is controlled in the torque control mode, the soft torque control method further includes: determining a torque compensation amount according to an actual torque of the motor and a set torque of the motor. 15 . A computer-readable storage medium storing instructions, which, when executed by a processor, enable the processor to execute the soft torque control method according to claim 12 .

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