Pushing type rotary guiding pushing force control method and system based on higher harmonics

Abstract

The invention relates to a pushing type rotary guiding pushing force control method and system based on higher harmonics. The method comprises the steps that vector decomposition is conducted on sidewall contact type rotary guiding lateral force, and sidewall contact force corresponding to a hydraulic device is obtained; based on the pushing force of the corresponding hydraulic device, designing a pushing force higher harmonic expression of the corresponding hydraulic device; according to the designed pushing force higher harmonic expression, extreme value solving is conducted on the higher harmonic signals through a conjugate ladder method, the pushing force extreme value of the corresponding hydraulic device is obtained, and a pushing force signal coefficient is obtained based on the pushing force extreme value; and obtaining a pushing force expression of the corresponding hydraulic device based on the obtained pushing force signal coefficient. The control method and system are simple, the pushing force can be changed gently, the design difficulty of an execution mechanism of the control system is reduced, good engineering application value is achieved, and the conjugate gradient method is small in storage amount needed for solving the extreme value, has step convergence and high stability and does not need any external parameter.

Description

Technical Field

[0001] This invention belongs to the technical field of oil and gas drilling equipment, and in particular to a method and system for controlling the pushing force of a push-type rotary steering system. More specifically, it relates to a method and system for controlling the pushing force of a push-type rotary steering system based on higher harmonics. Background Technology

[0002] Currently, the methods for decomposing the magnitude and direction of the desired lateral force of the drill bit are: (1) using two hydraulic devices to control the magnitude and direction of the guiding force, with the other serving as a floating support; (2) dividing the area, analyzing the favorable and unfavorable areas of the force based on the direction of the force and the angle between the hydraulic devices, and finally decomposing the force. The above methods can decompose the desired lateral force of the drill bit into three hydraulic devices, but these methods are complex and can lead to excessively rapid changes in the pushing force within the cycle. The uneven changes in the pushing force cause frequent operation of the rotary guide hydraulic device, resulting in instability of the lateral force tool face, causing misjudgment of the hydraulic system, and seriously affecting the directional control effect of the pushing rotary guide. Summary of the Invention

[0003] To mitigate the poor directional drilling effect caused by rapid changes in the hydraulic push force, a simple and gradual control method was designed based on vector decomposition and synthesis, analysis of the fundamental and higher harmonics of the control signal, and consideration of the hydraulic system's push force control range. This method, applied to a push-type rotary steerable system, reduces drill string oscillations, lowers the risk of downhole accidents, and demonstrates good field versatility and practicality.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: According to one aspect of the present invention, a method for controlling the pushing force of a push-type rotary guide based on higher harmonics is provided, comprising the following steps: 1) Decompose the lateral force of the push-type rotary guide into vectors to obtain the push force of the corresponding hydraulic device; 2) Based on the pushing force of the corresponding hydraulic device, design the expression for the higher harmonics of the pushing force of the corresponding hydraulic device; 3) Based on the design expression of the higher harmonics of the pushing force, the conjugate ladder method is used to solve the extreme values ​​of the higher harmonic signals to obtain the extreme values ​​of the pushing force of the corresponding hydraulic device, and the pushing force signal coefficients are obtained based on the extreme values ​​of the pushing force. 4) Based on the obtained pushing force signal coefficient, obtain the pushing force expression of the corresponding hydraulic device.

[0005] In one embodiment of the present invention, in step 1), the lateral force of the push-type rotary guide is vector decomposed to obtain the push force of the three hydraulic devices, and the three hydraulic devices are arranged on the push-type rotary guide system at 120° intervals from each other.

[0006] In one embodiment of the present invention, in step 1), the vector decomposition of the lateral force of the push-type rotary guide is as follows: ; ; ; ; Where Ɵ is the angle of the hydraulic device relative to the gravity side, F is the lateral force, β is the angle of the lateral force relative to the vertical axis, δ is the angle between the hydraulic device and the lateral force, F1, F2, and F3 are the pushing forces of the three hydraulic devices resulting from the decomposition of the lateral force, and k is the pushing force coefficient, k= .

[0007] In one embodiment of the present invention, in step 1), the initial pushing force of the three hydraulic devices is set to f0, then the pushing force of the corresponding hydraulic devices is expressed as: ; ; .

[0008] In one embodiment of the present invention, in step 2), the expression for the higher harmonic of the thrust force of the hydraulic device is: ; ; , Where t and q are the pushing force signal coefficients.

[0009] In one embodiment of the present invention, step 3) includes: 3.1) Select initial values ​​for the independent variable; 3.2) Calculate the gradient optimization direction in the nth step; 3.3) Based on the gradient, calculate the search step size, update the independent variables, and calculate the new gradient optimization direction; 3.4) Calculate the extreme value of the pushing force of the corresponding hydraulic device, and obtain the pushing force signal coefficient based on the extreme value of the pushing force.

[0010] In one embodiment of the present invention, in step 3.2), the gradient optimization direction in the nth step is: .

[0011] In one embodiment of the present invention, in step 3.3), the new gradient optimization direction is: .

[0012] In one embodiment of the present invention, in step 3.4), the obtained pushing force signal coefficients are t=0.09 and q=0.03.

[0013] In one embodiment of the present invention, in step 4), the expression for the pushing force of the corresponding hydraulic device is: ; ; .

[0014] According to another aspect of the present invention, a push-type rotary guide push-force control system based on higher harmonics is provided, comprising: A rotary guide DDS signal generator unit is configured to output analog signals and send three digital signals based on the push force expression of the corresponding hydraulic device derived according to the push force control method of the push-type rotary guide based on higher harmonics as described above. A rotary guide filter unit configured to filter three digital signals; A rotary guide hydraulic control unit is configured to execute filtered three-channel digital signals.

[0015] In one embodiment of the invention, the rotary guide DDS signal generator unit is further configured to adjust the time difference and send three digital signals to the hydraulic device.

[0016] In one embodiment of the present invention, the rotation-guided filter unit is a digital signal unit with an unscented Kalman filter.

[0017] In one embodiment of the invention, the rotary guide hydraulic control unit is further configured to extend and retract the rotary guide ribs and complete the rotary guide control signal curve.

[0018] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: The control method and system of this invention are simple, allowing for smooth changes in the pushing force and reducing the design difficulty of the control system's actuators, thus possessing significant engineering application value. Furthermore, the conjugate gradient method of this invention requires minimal storage for solving extrema, exhibits step convergence, high stability, and requires no external parameters. Attached Figure Description

[0019] Figure 1 A schematic flowchart of the push-type rotary guide push-force control method based on high-order harmonics provided by the present invention is shown. Figure 2 A schematic diagram of the hydraulic device used in this invention is shown; Figure 3 This diagram shows an exploded view of the lateral force of the push-type rotary guide in this invention; Figure 4 The signal diagram of the pushing force of the original three hydraulic devices is shown; Figure 5 A flowchart of the conjugate gradient algorithm used in this invention is shown; Figure 6 A graph showing the results of the conjugate gradient method of this invention is provided. Figure 7 The diagram shows the final push force signal of the three hydraulic devices after adopting the control method and system of the present invention; Figure 8 A simplified schematic diagram of a push-type rotary guide push force control system based on high-order harmonics provided by the present invention is shown. Detailed Implementation

[0020] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0021] like Figure 1 As shown, this invention provides a method for controlling the pushing force of a push-type rotary guide based on higher harmonics, the steps of which are as follows: S101: Vector decompose the lateral force of the push-type rotary guide to obtain the push force of the corresponding hydraulic device; S102: Based on the pushing force of the corresponding hydraulic device, design the high-order harmonic expression of the pushing force of the corresponding hydraulic device; S103: Based on the design expression of the high harmonic of the pushing force, the conjugate ladder method is used to solve the extreme value of the high harmonic signal to obtain the extreme value of the pushing force of the corresponding hydraulic device, and the pushing force signal coefficient is obtained based on the extreme value of the pushing force. S104: Based on the obtained pushing force signal coefficient, obtain the pushing force expression of the corresponding hydraulic device.

[0022] The control method described above in this invention is simple, can make the pushing force change smoothly, thus reducing the design difficulty of the control system actuator and has good engineering application value. Furthermore, the conjugate gradient method of this invention requires little storage to solve for extrema, has step convergence, high stability, and does not require any external parameters.

[0023] In the above-mentioned push-type rotary guide push force control method based on higher harmonics, in S101: Preferably, the lateral force of the push-type rotary guide is vector decomposed to obtain the pushing force of the three hydraulic devices. The three hydraulic devices are set on the push-type rotary guide system at 120° intervals from each other. The three hydraulic devices are equally spaced at angles, which can better facilitate the vector decomposition of the lateral force of the push-type rotary guide. Preferably, the vector decomposition of the lateral force of the push-type rotary guide can be: ; ; ; ; Where Ɵ is the angle of the hydraulic device relative to the gravity side, F is the lateral force, β is the angle of the lateral force relative to the vertical axis, δ is the angle between the hydraulic device and the lateral force, F1, F2, and F3 are the pushing forces of the three hydraulic devices decomposed from the lateral force, and k is the pushing force coefficient. Based on the principle of force decomposition, k = ; Preferably, the initial pushing force of the three hydraulic devices is set to f0, then the pushing force of the corresponding hydraulic devices is expressed as: ; ; .

[0024] In the above-mentioned push-type rotary guide push-force control method based on higher harmonics, in S102, the expression for the higher harmonic of the push-force of the corresponding hydraulic device can be: ; ; , Where t and q are the pushing force signal coefficients.

[0025] In the above-mentioned push-type rotary guide push force control method based on higher harmonics, S103 specifically includes: Choose initial values ​​for the independent variable; Calculate the gradient optimization direction in the nth step; Based on the gradient, calculate the search step size, update the independent variables, and calculate the new gradient optimization direction; Calculate the extreme value of the pushing force of the corresponding hydraulic device, and obtain the pushing force signal coefficient based on the extreme value of the pushing force.

[0026] Preferably, the gradient optimization direction in the nth step is: .

[0027] Preferably, the new gradient optimization direction is: .

[0028] Based on the above calculations, the obtained pushing force signal coefficients are t=0.09 and q=0.03.

[0029] Therefore, in S104, the expression for the pushing force of the corresponding hydraulic device is: ; ; .

[0030] In addition, such as Figure 8 As shown, the present invention also provides a push-type rotary guide push-force control system based on higher harmonics, comprising: Rotary guide DDS signal generator unit 01 is configured to output analog signals and send three digital signals based on the push force expression of the corresponding hydraulic device obtained according to the push force control method of push-type rotary guide based on higher harmonics as described above. Rotary guide filter unit 02, which is configured to filter three digital signals; Rotary guide hydraulic control unit 03 is configured to execute filtered three-channel digital signals.

[0031] In the aforementioned push-type rotary guide push force control system based on higher harmonics, the rotary guide DDS signal generator unit 01 is further configured to adjust the time difference and send three digital signals to the hydraulic device.

[0032] In the aforementioned push-type rotary guide push force control system based on higher harmonics, the rotary guide filter unit 02 is a digital signal unit with an unscented Kalman filter.

[0033] In the aforementioned push-type rotary guide push force control system based on higher harmonics, the rotary guide hydraulic control unit 03 is further configured to extend and retract the rotary guide ribs and complete the rotary guide control signal curve.

[0034] The technical solutions of the present invention will be described in detail below through specific embodiments.

[0035] The embodiments of the present invention disclose a push-type rotary guide push-force control method and system based on higher harmonics, which is applied in the field of push-type rotary guides, and is particularly suitable for the implementation of push-type rotary guide push-force control based on higher harmonics.

[0036] Traditional push-type rotary guide systems suffer from complex control methods and uneven push force changes, leading to frequent actuation of the rotary guide hydraulic device, instability of the lateral force tool face, and poor tilting effect. This invention proposes a simple control method and control system with a smooth push force variation by studying vector decomposition and the effects of higher harmonics. This system is simple to implement, and the smooth push force variation reduces the design difficulty of the control system's actuators, making it highly valuable for engineering applications.

[0037] Figure 1 A flowchart of a push-type rotary guide push-force control method based on high-order harmonics is shown. Figure 1 As shown, the steps of this control method are as follows.

[0038] Step S101: Decompose the lateral force of the push-type rotary guide into vectors to obtain the push force of the corresponding hydraulic device.

[0039] For step S101: Figure 2 A schematic diagram of the hydraulic device used in this invention is shown. Figure 2 As shown, R1, R2, and R3 are three hydraulic devices on the push-type rotary guide system. They are 120° apart and in the same plane. The push-type rotary guide system controls the drill bit to advance in a set direction by adjusting the pushing force of the three hydraulic devices, so that the drill bit receives a constant force of magnitude and direction.

[0040] The drilling process of a push-type rotary steerable system involves the surface sending commands to the system via a downcomer, specifying the magnitude and direction of the lateral force. The push-type rotary steerable system then distributes the desired lateral force across three hydraulic units according to these commands.

[0041] Figure 3 An exploded schematic diagram of the lateral force of the push-type rotary guide in this invention is shown. For example... Figure 3 As shown, the lateral force vector decomposition of the push-type rotary guide is as follows:

[0042]

[0043]

[0044]

[0045] Where Ɵ is the angle of R1 relative to the gravity side, F is the expected lateral force of the drill bit, β is the direction and the angle of the lateral force relative to the vertical axis, δ is the angle between R1 and the lateral force, F1, F2, and F3 are the magnitudes of the pushing forces of the three hydraulic devices, and k is the pushing force coefficient.

[0046] like Figure 3 As shown, let Fy be the force in the same direction as F1, and Fx be the force perpendicular to F1. According to the principle of force decomposition, we can deduce that:

[0047]

[0048]

[0049] Based on the above formula, the pushing force coefficient k = .

[0050] To ensure that the pushing force is greater than zero, the initial pushing force of R1, R2, and R3 is set to f0. Then, the pushing force of the corresponding hydraulic device can be expressed as:

[0051]

[0052] .

[0053] Steps S102-S104 involve smoothing the pushing force of the push-type rotary guide hydraulic device. The details are described below.

[0054] Step S102: Based on the pushing force of the corresponding hydraulic device, design the high-order harmonic expression of the pushing force of the corresponding hydraulic device.

[0055] For step S102: Figure 4 The diagram shows the original force signal of the three hydraulic devices. (As shown) Figure 4 As shown, the above formula for pushing force shows that the curve is cosine-shaped. At the inflection point of the pushing force, the top of the curve is not flat. When the tool surface changes rapidly, the pushing force output by the hydraulic device will be frequently adjusted, resulting in inaccurate pushing force position and difficulty in achieving the preset target of rotational guidance.

[0056] According to Fourier series, a square wave signal can be represented as a superposition of infinite odd-order harmonics. Applying high-order harmonic signals of equal magnitude to each hydraulic device, while ensuring the magnitude and direction of the resultant force remain unchanged, smooths the pushing force curve to guarantee stable operation of the hydraulic devices. To simplify the design, third and fifth harmonic signal components are added while meeting engineering requirements. The pushing force of the three hydraulic devices is expressed as follows, where t and q are the pushing force signal coefficients:

[0057]

[0058] .

[0059] Step S103: Based on the designed expression for the higher harmonics of the pushing force, the conjugate ladder method is used to solve for the extreme values ​​of the higher harmonic signals to obtain the extreme values ​​of the pushing force of the corresponding hydraulic device, and the pushing force signal coefficients are obtained based on the extreme values ​​of the pushing force.

[0060] For step S103: The conjugate ladder method is used to solve for the extrema of higher harmonic signals; the extrema of F1, F2, and F3 are solved.

[0061] Figure 5 A flowchart of the conjugate gradient algorithm used in this invention is shown. Figure 5 As shown, the conjugate gradient algorithm is as follows: Step S501: Select the initial value of the independent variable δ(n).

[0062] Step S502: Determine the gradient optimization direction p(n) for the nth step as follows: .

[0063] Step S503: Calculate the search step size T based on the gradient and update the independent variables; , And calculate the new degree optimization direction p(n+1); .

[0064] Step S504: Calculate the extreme value of the pushing force of the corresponding hydraulic device.

[0065] Step S505: Determine whether the calculated extreme value of the pushing force satisfies whether the absolute value of f(n)-f(n-1) is less than e. If it is not less than e, repeat step S502. If it is less than e, continue to the next step S506.

[0066] S506: Calculate the pushing force signal coefficient based on the extreme value of the pushing force, that is, calculate the pushing force parameters of the corresponding hydraulic devices F1, F2 and F3 based on the extreme value.

[0067] The pushing force signal coefficient is obtained based on the extreme points. When F1, F2 and F3 reach extreme values, the values ​​at the inflection points are approximately equal. The values ​​of t and q are solved, and t=0.09 and q=0.03 are obtained.

[0068] The results of the conjugate gradient method of this invention are shown in the figure below. Figure 6 As shown.

[0069] Step S104: Based on the obtained pushing force signal coefficient, obtain the pushing force expression of the corresponding hydraulic device.

[0070] For step S104: Step S104 finally yields the expression for the thrust of the corresponding hydraulic device:

[0071]

[0072] Its signal diagram is as follows Figure 7 As shown.

[0073] Figure 8 A simplified schematic diagram of a push-type rotary guide push-force control system based on high-order harmonics provided by the present invention is shown. Figure 8 As shown, the control system designed by this method consists of a rotary guide DDS signal generator unit 01, a rotary guide filter unit 02, and a rotary guide hydraulic controller unit 03. The rotary guide DDS signal generator unit 01 performs analog signal output based on the final expression obtained in step S104, adjusts the time difference, and sends three digital signals to the hydraulic device. The filter unit 02 is a digital signal unit with an unscented Kalman filter, which filters the three digital signals. The filtered signals are then used by relays to control the switching of the hydraulic device. The hydraulic controller unit 03 is the actuator for the three digital signals, responsible for the extension and retraction of the rotary guide ribs, thus completing the rotary guide control signal curve.

[0074] In summary, the signal waveform of the final pushing force is as follows: Figure 7 As shown, relative to the original signal waveform Figure 4 It can be seen that the pushing force at the top changes slowly, and the high-frequency combined force of each hydraulic device remains at 0, which is in line with the design expectation.

[0075] Therefore, the control method and system of this invention are simple, can make the pushing force change smoothly, thus reducing the design difficulty of the control system actuator and having good engineering application value. Furthermore, the conjugate gradient method of this invention requires little storage to solve for extrema, has step convergence, high stability, and does not require any external parameters.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications or equivalent substitutions made to the present invention without departing from the spirit and scope thereof should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for controlling the pushing force of a push-type rotary guide based on higher harmonics, characterized in that, Includes the following steps: 1) Decompose the lateral force of the push-type rotary guide into vectors to obtain the push force of the corresponding hydraulic device; 2) Based on the pushing force of the corresponding hydraulic device, design the expression for the higher harmonics of the pushing force of the corresponding hydraulic device; 3) Based on the design expression of the higher harmonics of the pushing force, the conjugate ladder method is used to solve the extreme values ​​of the higher harmonic signals to obtain the extreme values ​​of the pushing force of the corresponding hydraulic device, and the pushing force signal coefficients are obtained based on the extreme values ​​of the pushing force. 4) Based on the obtained pushing force signal coefficient, obtain the pushing force expression of the corresponding hydraulic device.

2. The push-force control method for a push-type rotary guide based on higher harmonics according to claim 1, characterized in that, In step 1), the lateral force of the push-type rotary guide is vector decomposed to obtain the pushing force of the three hydraulic devices, and the three hydraulic devices are arranged on the push-type rotary guide system at 120° intervals from each other.

3. The push-force control method for push-type rotary guides based on higher harmonics according to claim 2, characterized in that, In step 1), the vector decomposition of the lateral force of the push-type rotary guide is as follows: ； ； ； ； Where Ɵ is the angle of the hydraulic device relative to the gravity side, F is the lateral force, β is the angle of the lateral force relative to the vertical axis, δ is the angle between the hydraulic device and the lateral force, F1, F2, and F3 are the pushing forces of the three hydraulic devices resulting from the decomposition of the lateral force, and k is the pushing force coefficient, k= .

4. The push-force control method for push-type rotary guides based on higher harmonics according to claim 3, characterized in that, In step 1), the initial pushing force of the three hydraulic devices is set to f0. Then, the pushing force of the corresponding hydraulic devices is expressed as: ； ； 。 5. The push-force control method for a push-type rotary guide based on higher harmonics according to claim 4, characterized in that, In step 2), the expression for the higher harmonics of the thrust force of the corresponding hydraulic device is: ； ； ， Where t and q are the pushing force signal coefficients.

6. The method for controlling the pushing force of a push-type rotary guide based on higher harmonics according to claim 5, characterized in that, Step 3) includes: 3.1) Select initial values ​​for the independent variable; 3.2) Calculate the gradient optimization direction in the nth step; 3.3) Based on the gradient, calculate the search step size, update the independent variables, and calculate the new gradient optimization direction; 3.4) Calculate the extreme value of the pushing force of the corresponding hydraulic device, and obtain the pushing force signal coefficient based on the extreme value of the pushing force.

7. The push-force control method for a push-type rotary guide based on higher harmonics according to claim 6, characterized in that, In step 3.2), the gradient optimization direction in step n is: 。 8. The push-force control method for a push-type rotary guide based on higher harmonics according to claim 7, characterized in that, In step 3.3), the new gradient optimization direction is: 。 9. The push-force control method for a push-type rotary guide based on higher harmonics according to claim 8, characterized in that, In step 3.4), the obtained pushing force signal coefficients are t=0.09 and q=0.

03.

10. The push-force control method for a push-type rotary guide based on higher harmonics according to claim 9, characterized in that, In step 4), the expression for the pushing force of the corresponding hydraulic device is: ； ； 。 11. A push-type rotary guide push-force control system based on high-order harmonics, characterized in that, include: A rotary guide DDS signal generator unit is configured to output analog signals and send three digital signals based on the push force expression of the corresponding hydraulic device obtained according to the push force control method of the push-type rotary guide based on higher harmonics according to any one of the preceding claims 1-10. A rotary guide filter unit, configured to filter the three digital signals; A rotary guide hydraulic control unit, configured to execute the filtered three digital signals.

12. The push-type rotary guide push-force control system based on high-order harmonics according to claim 11, characterized in that, The rotary guide DDS signal generator unit is further configured to adjust the time difference and send three digital signals to the hydraulic device.

13. The push-type rotary guide push-force control system based on higher harmonics according to claim 11, characterized in that, The rotary guide filter unit is a digital signal unit with an unscented Kalman filter.

14. The push-type rotary guide push-force control system based on higher harmonics according to claim 11, characterized in that, The rotary guide hydraulic control unit is further configured to extend and retract the rotary guide ribs and complete the rotary guide control signal curve.

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