WO2018113319A1 - Control system and method for resisting stick-slip vibration of drill string - Google Patents

Abstract

Disclosed are a control system (20) and method for resisting stick-slip vibration of a drill string. The control system (20) and a top drive (11) form a torque feedback closed-loop control system. A data measurement module (21) is used to obtain a torque measurement value of the top drive (11), and a rotational speed correction value is output to the top drive (11) through calculation by a rotational speed control module (22) so as to control the top drive (11) so that same drives, according to a set rotational speed value, a drill string (121) to rotate, so that adverse effects of stick-slip vibration of the drill string (121) on a drilling operation can be eliminated so as to reduce wear of a bit (122), prevent damage of the drill string (121), prevent jamming during drilling, increase the drilling speed and increase the drilling efficiency. Parameters of a PI controller (111) of a speed controller in driving controllers of the top drive (11) do not need to be changed, and particularly in the case that certain top drives (11) do not allow a third-party user to change the parameters of the PI controller (111), this can still play a role and is applicable to any condition.

Description

Control system and method for anti-drill column stick-slip vibration Technical field

The invention relates to the technical field of anti-stick sliding of drill string for oil drilling, in particular to a control system and method for stick-slip vibration resistance of a drill string.

Background technique

During the actual drilling operation, the drill string interacts with the well wall or the bottom of the well. It often “stops” due to excessive torque. When the torque reaches a certain value, the drill string will suddenly and quickly release. This phenomenon is called The drill string is slippery. In particular, as the length of the drill string increases, the stiffness decreases, and the downhole friction increases, making it difficult to rotate the drill string downhole. The stick-slip of the drill string is often accompanied by vibration under the well, which easily causes the bit to collapse, shortens the life of the bit, and causes the drill string to break when it is severe.

The generation of stick-slip vibration of the drill string is caused by strong torsional vibration and downhole friction. This vibration is expressed as: the bit is stationary for a period of time, when the torque applied to the drill string is large enough, the bit suddenly rotates at a high speed, the speed can reach a large value in an instant, and the maximum speed even exceeds the number of top drive speeds. More than double, it is easy to cause fatigue of the drill string, reduce the working efficiency and life of the drill string, and make drilling work difficult to continue. At the same time, in the process of stick-slip vibration, the torque fluctuation is also very large. The actual torque is too large to exceed the limit torque that the equipment can withstand, causing the drilling operation to be interrupted and even causing destructive damage to the drilling equipment.

In order to eliminate stick-slip vibration, a method and apparatus for reducing stick-slip is disclosed in US Patent Application No. US Pat. No. 1,110, 232, 966 A1, which is mainly to change the parameters of the PI controller of the speed controller in the drive controller to achieve less stick-slip. When some top drives do not allow third-party users to change the parameters of the PI controller, they do not work.

Summary of the invention

The technical problem mainly solved by the invention is to provide a control system and method for resisting the stick-slip vibration of the drill string, which can eliminate the adverse influence of the stick-slip vibration of the drill string on the drilling operation, thereby reducing the wear of the drill bit, avoiding the damage of the drill string, and preventing the card. Drilling, increase drilling speed and increase drilling efficiency.

In order to solve the above technical problem, a technical solution adopted by the present invention is to provide an anti-drill column adhesive The sliding vibration control system is applied to a drilling machine, the drilling machine includes a top drive and a drill, the top drive includes a PI controller, a motor control unit and a motor connected in sequence, and the PI controller is configured to generate according to a speed setting value a control signal, the motor control unit for controlling the motor action according to the control signal, the drill comprising a drill string and a drill bit, the drill string transmitting the rotational speed and torque of the motor to the drill bit to provide a drill bit for the damaged rock formation The power control system includes a data measurement module and a speed control module, and the data measurement module is configured to measure a torque outputted by the top drive to obtain a torque measurement value, where the speed control module includes:

The frequency calculation unit is configured to acquire the stick-slip vibration characteristic parameter, and calculate the stick-slip vibration angle frequency by using the acquired stick-slip vibration characteristic parameter, and the calculation formula is:

Where k _p is the stiffness coefficient of the drill string, the unit is Nm, and J _p is the moment of inertia of the drill string, the unit is Nms ² ;

The index calculation unit is configured to calculate the stick-slip vibration index by using the torque measurement value, and the calculation formula is:

Where T is the average of the torque measurements over a calculation period, expressed as:

σ _T is the standard deviation of the torque measurement during a calculation period and is expressed as:

Where T _i is the real-time value of the torque measurement value at time i, i is the time serial number of one calculation cycle, and N is the number of torque measurement values in one calculation cycle;

a determining unit, configured to determine whether the stick-slip vibration indicator is greater than a preset value;

The impedance calculation unit is configured to calculate the characteristic impedance of the drill string by using the acquired stick-slip vibration characteristic parameter when the stick-slip vibration index is greater than a preset value, and the calculation formula is:

Where G is the shear modulus of the drill string, the unit is Nm ^-2 , ρ is the density of the drill string, the unit is kg / m ³ , I _p is the pole moment of inertia of the drill string, the unit is m ⁴ , expressed as :

D is the outer diameter of the drill string, the unit is m, and d is the inner diameter of the drill string, and the unit is m;

a moment of inertia calculation unit for acquiring a top drive parameter, and calculating a top drive rotation by using the top drive parameter Inertia, the formula is:

J _T =J ₀ +n(i ² J _M )

Where n is the number of motors of the top drive, i is the gear ratio of the top drive, J _M is the moment of inertia of the rotor of the motor, and J ₀ is the moment of inertia of the top drive body;

The stiffness coefficient calculation unit is configured to convert the top drive into an elastic system, and calculate the stiffness coefficient of the elastic system by using the stick-slip vibration angular frequency and the top drive moment of inertia, and the calculation formula is:

And calculating the dynamic characteristic parameter of the elastic system by using the characteristic impedance of the drill string, and the calculation formula is:

Where c is the damping coefficient of the elastic system, the unit is Nms;

a PI calculation unit, configured to calculate a P parameter correction value and an I parameter correction value by using the dynamic characteristic parameter, and the calculation formula is:

Where K _p is the P parameter correction value, K _i is the I parameter correction value, and a is a preset proportional coefficient;

a function generating unit, configured to obtain a matching transfer function of a PI controller matching the dynamic characteristic parameter by using the P parameter correction value and the I parameter correction value, and obtain a PI by using a P parameter and an I parameter of the PI controller An initial transfer function of the controller, and using the initial transfer function and the matching transfer function to calculate a rotational speed correction transfer function;

And a rotation speed setting unit configured to output a rotation speed correction value to the top drive by using the torque measurement value and the rotation speed correction transfer function to control the top drive to drive the drill string to rotate according to the rotation speed setting value.

Preferably, the calculation formula of the rotation speed correction transfer function is:

Where H(s) is the rotational speed correction transfer function, G ₁ (s) is the matching transfer function, and G(s) is the initial transfer function.

Preferably, the control system further comprises an input display module, wherein the input display module is configured to input a stick-slip vibration characteristic parameter, a top drive parameter or a display speed and torque of the top drive output.

In order to solve the above technical problem, another technical solution adopted by the present invention is to provide an anti-drill column The control method of stick-slip vibration is applied to a drilling machine, the drilling machine includes a top drive and a drill, the top drive includes a PI controller, a motor control unit and a motor connected in sequence, and the PI controller is used for setting according to a rotation speed Generating a control signal, the motor control unit for controlling the motor action according to the control signal, the drill comprising a drill string and a drill bit, the drill string transmitting the rotational speed and torque of the motor to the drill bit, and the drill bit is damaged Providing power, characterized in that the control method comprises the following steps:

S1: used to obtain the stick-slip vibration characteristic parameter, and calculate the stick-slip vibration angular frequency by using the obtained stick-slip vibration characteristic parameter, and the calculation formula is:

Where k _p is the stiffness coefficient of the drill string, the unit is Nm, and J _p is the moment of inertia of the drill string, the unit is Nms ² ;

S2: measuring the torque outputted by the top drive to obtain a torque measurement value, and calculating the stick-slip vibration index by using the torque measurement value, and the calculation formula is:

Where T is the average of the torque measurements over a calculation period, expressed as:

σ _T is the standard deviation of the torque measurement during a calculation period and is expressed as:

Where T _i is the real-time value of the torque measurement value at time i, i is the time serial number of one calculation cycle, and N is the number of torque measurement values in one calculation cycle;

S3: determining whether the stick-slip vibration indicator is greater than a preset value;

S4: If the stick-slip vibration index is greater than a preset value, calculate the characteristic impedance of the drill string by using the acquired stick-slip vibration characteristic parameter, and the calculation formula is:

Where G is the shear modulus of the drill string, the unit is Nm ^-2 , ρ is the density of the drill string, the unit is kg / m ³ , I _p is the pole moment of inertia of the drill string, the unit is m ⁴ , expressed as :

D is the outer diameter of the drill string, the unit is m, and d is the inner diameter of the drill string, and the unit is m;

S5: obtaining a top drive parameter, and calculating a top drive moment of inertia by using the top drive parameter, and the calculation formula is:

J _T =J ₀ +n(i ² J _M )

Where n is the number of motors of the top drive, i is the gear ratio of the top drive, J _M is the moment of inertia of the rotor of the motor, and J ₀ is the moment of inertia of the top drive body;

S6: The top drive is equivalent to an elastic system, and the stiffness coefficient of the elastic system is calculated by using the stick-slip vibration angular frequency and the top drive moment of inertia, and the calculation formula is:

And calculating the dynamic characteristic parameter of the elastic system by using the characteristic impedance of the drill string, and the calculation formula is:

Where c is the damping coefficient of the elastic system, the unit is Nms;

S7: used to calculate the P parameter correction value and the I parameter correction value by using the dynamic characteristic parameter, and the calculation formula is:

Where K _p is the P parameter correction value, K _i is the I parameter correction value, and a is a preset proportional coefficient;

S8: using the P parameter correction value and the I parameter correction value to obtain a matching transfer function of the PI controller matching the dynamic characteristic parameter, and using the P parameter and the I parameter of the PI controller to obtain an initial of the PI controller Transmitting a function, and calculating a rotation speed correction transfer function by using the initial transfer function and the matching transfer function;

S9: using the torque measurement value and the rotation speed correction transfer function to output a rotation speed correction value to the top drive to control the top drive to drive the drill string to rotate according to the rotation speed setting value.

Preferably, the calculation formula of the rotation speed correction transfer function is:

Where H(s) is the rotational speed correction transfer function, G ₁ (s) is the matching transfer function, and G(s) is the initial transfer function.

Preferably, after the step S9, the control method further includes: S10: determining whether the stick-slip vibration is successfully eliminated; S11: if unsuccessful, re-adjusting the scale factor, and performing step S4 again; S12: if successful, Then stop outputting the speed correction value to the top drive.

The beneficial effects of the present invention are: different from the prior art, the control system and the top drive of the present invention The torque feedback closed-loop control system is composed, and the torque measurement value of the top drive is obtained by using the data measurement module, and the rotation speed control module calculates the rotation speed correction value to the top drive to control the top drive to drive the drill string rotation according to the rotation speed setting value, thereby eliminating The adverse effects of the stick-slip vibration of the drill string on the drilling operation to reduce the wear of the drill bit, avoid damage to the drill string, prevent stuck drilling, increase the drilling speed, and increase the drilling efficiency. Compared with the technical solution disclosed in US20110232966A1, the control system and method need not be needed. Changing the parameters of the PI controller of the speed controller in the top drive controller, especially if some top drives do not allow third-party users to change the parameters of the PI controller, still work, and can be used in any situation.

DRAWINGS

Figure 1 is a schematic structural view of a drilling machine;

2 is a schematic structural view of a control system for anti-drill column stick-slip vibration according to an embodiment of the present invention;

Figure 3 is a schematic illustration of an equivalent elastic system of a top drive of a drill;

4 is a schematic diagram of a closed loop control principle of a control system for anti-drill column stick-slip vibration according to an embodiment of the present invention;

5 is a schematic diagram of a parameter setting interface of an input display module of a control system for anti-drill column stick-slip vibration according to an embodiment of the present invention;

6 is a graph showing a trend of parameter variation after using a control system for anti-drill column stick-slip vibration according to an embodiment of the present invention;

7 is a trend chart of parameter changes after deactivating the control system of the anti-drill column stick-slip vibration of the embodiment of the present invention;

FIG. 8 is a schematic flow chart of a method for controlling stick-slip vibration resistance of a drill string according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Referring to FIGS. 1 to 4, the control system for the anti-drill column stick-slip vibration of the embodiment of the present invention is applied to a drilling machine 10. The drilling machine 10 includes a top drive 11 and a drill 12, and the top drive 11 includes a PI controller 111 connected in sequence, and a motor control. The unit 112 and the motor 113, the PI controller 111 is configured to generate a control signal according to the speed set value, the motor control unit 112 is configured to control the action of the motor 113 according to the control signal, the drill 12 includes a drill string 121 and a drill bit 122, and the drill string 121 will The speed and torque of the motor 113 are transmitted to the drill bit 122, breaking the drill bit 122 The damaged rock layer provides power.

The control system 20 includes a data measurement module 21 and a rotation speed control module 22 for measuring the torque output by the top drive 11 to obtain a torque measurement value. The rotation speed control module 22 includes a frequency calculation unit 221, an index calculation unit 222, and a judgment. The unit 223, the impedance calculation unit 224, the inertia calculation unit 225, the coefficient calculation unit 226, the function generation unit 227, and the rotation speed setting unit 228.

The frequency calculation unit 221 is configured to acquire the stick-slip vibration characteristic parameter, and calculate the stick-slip vibration angle frequency by using the stick-slip vibration characteristic parameter, and the calculation formula is:

Where k _p is the stiffness coefficient of the drill string, the unit is Nm, and J _p is the moment of inertia of the drill string, and the unit is Nms ² . The stiffness coefficient and moment of inertia of the drill string are all characteristic parameters of the stick-slip vibration. The stick-slip vibration characteristic parameters can be input by the user or input by a third party.

During the drilling operation, it is known from the mechanism of stick-slip vibration that the drill string rotation angle frequency ω _p and the stick-slip vibration angle frequency ω _s satisfy the following relationship:

ω _p ≈ω _s (2)

According to the geometric and mechanical analysis of the mechanical structure, the drill string rotation angle frequency ω _{p is} calculated as follows:

Set the number of drill strings to n, including drill collars. Each drill string has a stiffness coefficient of k _pi and a moment of inertia of J _pi .

Formula (1) can be obtained by substituting the above formulas.

The index calculation unit 222 is configured to calculate the stick-slip vibration index by using the torque measurement value, and the calculation formula is:

Where T is the average of the torque measurements over a calculation period, expressed as:

σ _T is the standard deviation of the torque measurement during a calculation period and is expressed as:

Where T _i is the real-time value of the torque measurement value at time i, i is the time serial number of one calculation cycle, and N is the number of torque measurement values in one calculation cycle. The stick-slip vibration index reflects the severity of the stick-slip vibration. The larger the value, the more obvious the stick-slip vibration phenomenon of the drill string.

The determining unit 223 is configured to determine whether the stick-slip vibration index is greater than a preset value. The preset value is, for example, 30%.

The impedance calculation unit 224 is configured to calculate the characteristic impedance of the drill string by using the stick-slip vibration characteristic parameter when the stick-slip vibration index is greater than a preset value, and the calculation formula is:

Where G is the shear modulus of the drill string, the unit is Nm ^-2 , ρ is the density of the drill string, the unit is kg / m ³ , I _p is the pole moment of inertia of the drill string, the unit is m ⁴ , expressed as :

D is the outer diameter of the drill string, the unit is m, and d is the inner diameter of the drill string, and the unit is m.

The moment of inertia calculation unit 225 is configured to acquire the top drive parameter, and calculate the top drive moment of inertia by using the top drive parameter, and the calculation formula is:

J _T =J ₀ +n(i ² J _M ) (10)

Wherein the number of the motor n is a top drive, i is the top drive gear ratio, J _M is the moment of inertia of the motor rotor, J ₀ is the moment of inertia of the top drive main body, the number of motor top drive, gear ratio, The moment of inertia of the rotor of the motor and the moment of inertia of the top drive body are top drive parameters, and the top drive parameters can be input by the user or by a third party.

The stiffness coefficient calculation unit 226 is configured to convert the top drive into an elastic system, and calculate the stiffness coefficient of the elastic system by using the stick-slip vibration angular frequency and the top drive moment of inertia, and the calculation formula is:

And calculating the dynamic characteristic parameters of the elastic system by using the characteristic impedance of the drill string, and the calculation formula is:

Where c is the elastic system damping coefficient in Nms.

According to the concept of torque feedback, the torque feedback method is to adjust the top drive speed in response to the fluctuation of the torque, so that the top drive absorbs or suppresses the stick-slip vibration. The drill string is equivalent to the propagation conductor of the torsion wave. Due to the friction of the drill string on the drill string, the torque of the drill string changes, and a torsional wave is generated. The waveform propagates up the drill string to the surface, and the top drive acts as a fixed end of the waveform. The torsional wave reflects downward. Thus, the terminal impedance of the top drive as the end is defined as Z, introducing the concept of plural, which is expressed as follows:

Te ^iωt =-ZΩe ^iωt (13)

Where ω is the angular frequency, the unit is rad/s, T is the amplitude of the complex expression of the torque, the unit is Nm, Ω is the amplitude of the complex expression of the rotational speed, the unit is rad/s.

In order to analyze the attenuation characteristics of the top drive reflection waveform, the terminal reflection coefficient r, r is introduced as the ratio of the reflected wave to the incident wave. r is related to the terminal impedance Z (in Nms) and the drill string characteristic impedance ζ (unit is Nms), which is expressed as follows:

Equation (14) applies to any situation. Taking the top drive as an example, if Z>>ζ, then r=-1, the torsional wave is reflected 100% along the drill string to the bottom drill string, causing the bottom drill string to fluctuate drastically; if Z<<ζ, then r= 1. The energy of the torsional wave is concentrated at the top drive, and the top drive fluctuates drastically. The closer the Z is to ζ, the smaller the reflection coefficient is, and the stronger the top drive absorbs or suppresses the torsional vibration. The purpose of the torque feedback is to make Z close to ζ, thereby eliminating or suppressing the stick-slip vibration.

To further explain the torque feedback principle, the drill string is equivalent to a rigid spring, the characteristic impedance is ζ, and the top drive is also equivalent to a rigid elastic system. As the end of the drill string, the characteristic impedance is Z. The equivalent structure is shown in Figure 3. The terminal impedance Z can also be expressed by the following formula:

Where c is the damping of the top drive equivalent model, the unit is Nms. k is the stiffness coefficient in Nm, and J is the moment of inertia in Nms ² .

The top drive 11 is equivalent to a rigid elastic system, and the parameters are defined as follows: the elastic system rotational angular velocity is ω, the twisted shape becomes x, and the torque is T. When the system is running stably, the variables satisfy the following relationships:

x=∫ωdt

T-cω-kx=0 (16)

The above formula changes to:

T=cω+k∫ωdt=f(ω) (17)

Thus, the above equation can be seen as a function of T with respect to ω.

It can be seen from the characteristics of the rigid elastic system that the reference direction of T and ω is opposite, then equation (13) can be transformed into:

|T|=Z|ω| (18)

It can be concluded from the above formulas (15) and (17) that Z is related to c and k, c is the inherent characteristic of the top-elastic equivalent elastic system, and k is the dynamic characteristic of the elastic system related to the angular frequency ω, and the adjustment c, k You can adjust Z.

It can be seen from the above theory that when Z is close to ζ and Z is a real number, the reflection coefficient r is the smallest.

For the top drive 11, the top drive 11 is rigidly coupled to the drill string 12, and the rotational speed ω _{T of the} top drive 11 satisfies:

ω _T =ω _p ≈ω _s (19)

Then, according to the formula (19), the formula (12) can be obtained.

Considering the dynamic characteristics of the rig, the current speed of the top drive 11 is ω ₀ , the torque is T ₀ , and the elapsed time Δt becomes ω ₁ , T ₁ , then:

The function of T with respect to ω described by equation (17) can also be expressed by the following formula:

T=c(ω ₁ -ω ₀ )+k∫(ω ₁ -ω ₀ )dt (21)

The PI calculation unit 227 is configured to calculate the P parameter correction value and the I parameter correction value by using the dynamic characteristic parameter, and the calculation formula is:

Where K _p is the P parameter correction value, K _i is the I parameter correction value, and a is the preset proportional coefficient, and the range is 0-100%.

Figure 4 is a schematic diagram of the closed-loop control principle. The PI controller is expressed as:

y(t)=K _p e(t)+K _i ∫e(t)dt (23)

make:

It can be seen from Fig. 4 and the above formula that the top drive equivalent elastic system can analyze the system by using the time domain analysis method of the control theory, and adjust the terminal impedance of the top drive by changing the proportional gain K _p and the integral coefficient K _{i of the} PI controller. Z, you can get the formula (22).

Among them, c and k are calculated as shown in formula (12).

The function generating unit 228 is configured to obtain a matching transfer function of the PI controller matching the dynamic characteristic parameter by using the P parameter correction value and the I parameter correction value, and obtain the initial of the PI controller 111 by using the P parameter and the I parameter of the PI controller 111. Transfer the function and calculate the rotation speed correction transfer function using the initial transfer function and the matching transfer function. According to the schematic diagram of the closed-loop control principle shown in FIG. 4, the initial transfer function is G(s), and the rotational speed correction transfer function is H(s), then in the closed-loop control, the PI controller matching the dynamic characteristic parameter The matching transfer function G ₁ (s) can be expressed by the following formula:

The formula (25) is transformed to obtain the calculation formula of the rotational speed correction transfer function:

Where, H (s) is the transfer function of the correction rotation speed, G ₁ (s) to match the transfer function, G (s) is the transfer function of the original.

The rotational speed setting unit 229 is configured to output a rotational speed correction value to the top drive 11 by using the torque measurement value and the rotational speed correction transfer function to control the top drive 11 to drive the drill string 12 to rotate according to the rotational speed set value. The top drive 11 obtains the speed set value by combining the preset speed value and the speed correction value, thereby driving the drill string 12 to rotate according to the speed set value.

In this embodiment, the control system further includes an input display module 23 for inputting a stick-slip vibration characteristic parameter, a top drive parameter, or a display of the top drive output speed and torque. As shown in FIG. 5, it is a schematic diagram of a parameter setting interface of an input display module.

Referring to Figures 6 and 7, Figure 6 shows the variation of top drive speed and torque after activation of the control system of the present invention. Among them, the line A represents the torque, the line B represents the rotational speed, the line C represents the start-stop signal of the control system, and the line D represents the degree of stick-slip vibration. The control system is activated at 0:12:29. From the fluctuation of the line B, it can be seen that the control system is eliminating the stick-slip vibration, and after the stick-slip vibration is eliminated, the line A fluctuation is significantly smaller. Figure 7 shows the change in top drive speed and torque after the control system is deactivated. The control system was deactivated at 8:48:45, and the line A fluctuated gradually.

FIG. 8 is a schematic flow chart of a method for controlling stick-slip vibration resistance of a drill string according to an embodiment of the present invention. The control method of the embodiment is applied to a drilling machine, the drilling machine comprises a top drive and a drilling tool, the top drive comprises a PI controller, a motor control unit and a motor connected in sequence, and the PI controller is configured to generate a control signal according to the speed setting value, The motor control unit is configured to control the motor action according to a control signal comprising a drill string and a drill bit, the drill string transmitting the rotational speed and torque of the motor to the drill bit to power the damaged rock formation of the drill bit. The control method includes the following steps:

S1: used to obtain the characteristic parameters of the stick-slip vibration, and calculate the stick-slip vibration angle frequency by using the stick-slip vibration characteristic parameter. The calculation formula is:

Where k _p is the stiffness coefficient of the drill string, the unit is Nm, and J _p is the moment of inertia of the drill string, and the unit is Nms ² .

S2: The torque measured by the top drive is measured to obtain the torque measurement value, and the viscosity measurement value is used to calculate the stick-slip vibration index, and the calculation formula is:

Where T is the average of the torque measurements over a calculation period, expressed as:

σ _T is the standard deviation of the torque measurement during a calculation period and is expressed as:

Where T _i is the real-time value of the torque measurement value at time i, i is the time serial number of one calculation cycle, and N is the number of torque measurement values in one calculation cycle.

S3: Determine whether the stick-slip vibration index is greater than a preset value.

S4: If the stick-slip vibration index is greater than the preset value, calculate the characteristic impedance of the drill string by using the stick-slip vibration characteristic parameter, and the calculation formula is:

Where G is the shear modulus of the drill string, the unit is Nm ^-2 , ρ is the density of the drill string, the unit is kg / m ³ , I _p is the pole moment of inertia of the drill string, the unit is m ⁴ , expressed as :

D is the outer diameter of the drill string, the unit is m, and d is the inner diameter of the drill string, and the unit is m;

S5: Obtain the top drive parameter, and calculate the top drive moment of inertia by using the top drive parameter. The calculation formula is:

J _T =J ₀ +n(i ² J _M )

Where n is the number of motors of the top drive, i is the gear ratio of the top drive, J _M is the rotational inertia of the rotor of the motor, and J ₀ is the moment of inertia of the top drive body.

S6: The top drive is equivalent to the elastic system, and the stiffness coefficient of the elastic system is calculated by the visco-slip vibration angular frequency and the top drive moment of inertia. The calculation formula is:

And calculating the dynamic characteristic parameters of the elastic system by using the characteristic impedance of the drill string, and the calculation formula is:

Where c is the damping coefficient of the elastic system, the unit is Nms;

S7: Calculate the P parameter correction value and the I parameter correction value by using the dynamic characteristic parameter, and the calculation formula is:

Where K _p is the P parameter correction value, K _i is the I parameter correction value, and a is the preset proportional coefficient.

S8: Using the P parameter correction value and the I parameter correction value to obtain the matching transfer function of the PI controller matching the dynamic characteristic parameter, and using the P parameter and the I parameter of the PI controller to obtain the initial transfer function of the PI controller, and using the initial The transfer function and the matching transfer function calculate the rotational speed correction transfer function. Among them, the calculation formula of the rotation speed correction transfer function is:

Where H(s) is the rotational speed correction transfer function, G ₁ (s) is the matching transfer function, and G(s) is the initial transfer function.

S9: Using the torque measurement value and the rotation speed correction transfer function to output the rotation speed correction value to the top drive to control the top drive to drive the drill string rotation according to the rotation speed setting value.

In this embodiment, after step S9, the control method further includes:

S10: determining whether the stick-slip vibration is successfully eliminated;

S11: If it is unsuccessful, re-adjust the scale factor, and repeat step S4;

S12: If successful, stop outputting the speed correction value to the top drive.

The above is only the embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformation of the present invention and the contents of the drawings may be directly or indirectly applied to other related technologies. The fields are all included in the scope of patent protection of the present invention.

Claims (6)

1. A control system for anti-drill column stick-slip vibration is applied to a drilling machine, the drilling machine includes a top drive and a drill, the top drive includes a PI controller, a motor control unit and a motor connected in sequence, and the PI controller is used for Generating a control signal according to a speed setting value, the motor control unit is configured to control the motor action according to the control signal, the drilling tool includes a drill string and a drill bit, and the drill string transmits the speed and torque of the motor to the drill bit Providing power for the drill bit damaged rock formation, wherein the control system comprises a data measurement module and a rotational speed control module, wherein the data measurement module is configured to measure a torque outputted by the top drive to obtain a torque measurement value, and the rotational speed control module include:

   The frequency calculation unit is configured to acquire the stick-slip vibration characteristic parameter, and calculate the stick-slip vibration angle frequency by using the stick-slip vibration characteristic parameter, and the calculation formula is:

   

   Where k _p is the stiffness coefficient of the drill string, the unit is Nm, and J _p is the moment of inertia of the drill string, the unit is Nms ² ;

   The index calculation unit is configured to calculate the stick-slip vibration index by using the torque measurement value, and the calculation formula is:

   

   Where T is the average of the torque measurements over a calculation period, expressed as:

   

   σ _T is the standard deviation of the torque measurement during a calculation period and is expressed as:

   

   Where T _i is the real-time value of the torque measurement value at time i, i is the time serial number of one calculation cycle, and N is the number of torque measurement values in one calculation cycle;

   a determining unit, configured to determine whether the stick-slip vibration indicator is greater than a preset value;

   The impedance calculation unit is configured to calculate the characteristic impedance of the drill string by using the stick-slip vibration characteristic parameter when the stick-slip vibration index is greater than a preset value, and the calculation formula is:

   

   Where G is the shear modulus of the drill string, the unit is Nm ^-2 , ρ is the density of the drill string, the unit is kg / m ³ , I _p is the pole moment of inertia of the drill string, the unit is m ⁴ , expressed as :

   

   D is the outer diameter of the drill string, the unit is m, and d is the inner diameter of the drill string, and the unit is m;

   The moment of inertia calculation unit is configured to obtain a top drive parameter, and calculate a top drive moment of inertia by using the top drive parameter, and the calculation formula is:

   J _T =J ₀ +n(i ² J _M )

   Where n is the number of motors of the top drive, i is the gear ratio of the top drive, J _M is the moment of inertia of the rotor of the motor, and J ₀ is the moment of inertia of the top drive body;

   The stiffness coefficient calculation unit is configured to convert the top drive into an elastic system, and calculate the stiffness coefficient of the elastic system by using the stick-slip vibration angular frequency and the top drive moment of inertia, and the calculation formula is:

   

   And calculating the dynamic characteristic parameter of the elastic system by using the characteristic impedance of the drill string, and the calculation formula is:

   

   Where c is the damping coefficient of the elastic system, the unit is Nms;

   a PI calculation unit, configured to calculate a P parameter correction value and an I parameter correction value by using the dynamic characteristic parameter, and the calculation formula is:

   

   Where K _p is the P parameter correction value, K _i is the I parameter correction value, and a is a preset proportional coefficient;

   a function generating unit, configured to obtain a matching transfer function of a PI controller matching the dynamic characteristic parameter by using the P parameter correction value and the I parameter correction value, and obtain a PI by using a P parameter and an I parameter of the PI controller An initial transfer function of the controller, and using the initial transfer function and the matching transfer function to calculate a rotational speed correction transfer function;

   The rotation speed setting unit is configured to output the rotation speed correction value to the top drive by using the torque measurement value and the rotation speed correction transfer function to control the top drive to drive the drill string rotation according to the rotation speed setting value.
2. The control system according to claim 1, wherein the calculation formula of the rotational speed correction transfer function is:

   

   Where H(s) is the rotational speed correction transfer function, G ₁ (s) is the matching transfer function, and G(s) is the initial transfer function.
3. A control system according to claim 1 or 2, wherein said control system further comprises The input display module is configured to input a stick-slip vibration characteristic parameter, a top drive parameter, or a display speed and torque of the top drive output.
4. A control method for anti-drill column stick-slip vibration is applied to a drilling machine, the drilling machine includes a top drive and a drill, the top drive includes a PI controller, a motor control unit and a motor connected in sequence, and the PI controller is used for Generating a control signal according to a speed setting value, the motor control unit is configured to control the motor action according to the control signal, the drilling tool includes a drill string and a drill bit, and the drill string transmits the speed and torque of the motor to the drill bit Providing power to the drill bit damaged rock formation, characterized in that the control method comprises the following steps:

   S1: used to obtain the stick-slip vibration characteristic parameter, and calculate the stick-slip vibration angle frequency by using the stick-slip vibration characteristic parameter, and the calculation formula is:

   

   Where k _p is the stiffness coefficient of the drill string, the unit is Nm, and J _p is the moment of inertia of the drill string, the unit is Nms ² ;

   S2: measuring the torque outputted by the top drive to obtain a torque measurement value, and calculating the stick-slip vibration index by using the torque measurement value, and the calculation formula is:

   

   Where T is the average of the torque measurements over a calculation period, expressed as:

   

   σ _T is the standard deviation of the torque measurement during a calculation period and is expressed as:

   

   Where T _i is the real-time value of the torque measurement value at time i, i is the time serial number of one calculation cycle, and N is the number of torque measurement values in one calculation cycle;

   S3: determining whether the stick-slip vibration indicator is greater than a preset value;

   S4: If the stick-slip vibration index is greater than a preset value, calculate the characteristic impedance of the drill string by using the acquired stick-slip vibration characteristic parameter, and the calculation formula is:

   

   Where G is the shear modulus of the drill string, the unit is Nm ^-2 , ρ is the density of the drill string, the unit is kg / m ³ , I _p is the pole moment of inertia of the drill string, the unit is m ⁴ , expressed as :

   

   D is the outer diameter of the drill string, the unit is m, and d is the inner diameter of the drill string, and the unit is m;

   S5: obtaining a top drive parameter, and calculating a top drive moment of inertia by using the top drive parameter, and the calculation formula is:

   J _T =J ₀ +n(i ² J _M )

   Where n is the number of motors of the top drive, i is the gear ratio of the top drive, J _M is the moment of inertia of the rotor of the motor, and J ₀ is the moment of inertia of the top drive body;

   S6: The top drive is equivalent to an elastic system, and the stiffness coefficient of the elastic system is calculated by using the stick-slip vibration angular frequency and the top drive moment of inertia, and the calculation formula is:

   

   And calculating the dynamic characteristic parameter of the elastic system by using the characteristic impedance of the drill string, and the calculation formula is:

   

   Where c is the damping coefficient of the elastic system, the unit is Nms;

   S7: Calculating the P parameter correction value and the I parameter correction value by using the dynamic characteristic parameter, and the calculation formula is:

   

   Where K _p is the P parameter correction value, K _i is the I parameter correction value, and a is a preset proportional coefficient;

   S8: using the P parameter correction value and the I parameter correction value to obtain a matching transfer function of the PI controller matching the dynamic characteristic parameter, and using the P parameter and the I parameter of the PI controller to obtain an initial of the PI controller Transmitting a function, and calculating a rotation speed correction transfer function by using the initial transfer function and the matching transfer function;

   S9: using the torque measurement value and the rotation speed correction transfer function to output a rotation speed correction value to the top drive to control the top drive to drive the drill string to rotate according to the rotation speed setting value.
5. The control method according to claim 4, wherein the calculation formula of the rotation speed correction transfer function is:

   

   Where H(s) is the rotational speed correction transfer function, G ₁ (s) is the matching transfer function, and G(s) is the initial transfer function.
6. The control method according to claim 4 or 5, characterized in that after step S9, the The control method further includes:

   S10: determining whether the stick-slip vibration is successfully eliminated;

   S11: If unsuccessful, re-adjust the scale factor, and repeat step S4;

   S12: If successful, stop outputting the speed correction value to the top drive.

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