A dynamic solution and error compensation method for gyroscope under complex vibration

Abstract

The present invention provides a dynamic solution and error compensation method for a gyroscope under complex vibration, constructs a vibration transmission model of a near-drill bit while-drilling measurement system by analyzing various parameters in the mining process; analyzes the influence of various errors of gyroscopes and accelerometers on the measurement results, constructs error models of gyroscopes and accelerometers in the near-drill bit while-drilling measurement system, and uses an empirical mode decomposition algorithm to realize intelligent extraction of motion characteristics of the near-drill bit while-drilling measurement system; collects three-axis acceleration and three-axis angular velocity signals of the drill tool to establish a dynamic continuous solution model for the three-dimensional attitude of the drill tool, analyzes the cone error compensation strategy of angular vibration under attitude solution and the rowing error compensation of linear vibration under velocity solution, and establishes a dynamic correction strategy for vibration errors. The present invention improves the measurement accuracy of MEMS gyroscopes and completes the efficient mining of coalbed methane.

Description

Technical Field

[0001] The invention relates to the field of data processing, and in particular to a dynamic solution and error compensation method of a gyroscope under complex vibration. Background Art

[0002] The exploitation and utilization of coalbed methane is of great significance in ensuring safe production in coal mines, optimizing the energy industry structure, and protecting the ecological environment. Improving coalbed methane recovery rate and reducing drilling costs are particularly important for the vigorous development of coalbed methane. To achieve the industrialization and scale of coalbed methane development, multi-branch cluster well drilling technology with directional drilling as the core has gradually been formed.

[0003] The fiber optic gyroscopes and laser gyroscopes used in conventional directional drilling are large in size and high in cost, and cannot be used in coalbed methane branch well sidetracking and small-sized radial horizontal well environments. In the past two years, with the rise of low-cost, small-sized, and high-performance micro-electromechanical system (MEMS) sensors, gyroscopes have begun to be used in coalbed methane directional horizontal wells.

[0004] However, the rotation speed is generally high during coalbed methane drilling, and the traditional inclinometer while drilling is generally installed more than 15 meters away from the drill bit, and its measurement information is delayed, so the measurement sub with MEMS gyroscope combined with accelerometer is directly installed near the drill bit to reduce the impact. However, the MEMS inclinometer while drilling installed near the drill bit will be directly affected by the impact vibration caused by the rotation of the drill tool and the rock breaking of the drill bit, which will seriously affect the accuracy of the drilling trajectory while drilling measurement.

[0005] Therefore, it is necessary to study a dynamic solution and error compensation method for the gyroscope under complex vibration, to compensate for the error caused by the alignment of the MEMS gyroscope installed near the drill bit, to improve the measurement accuracy, and to complete the effective mining of coalbed methane. Summary of the invention

[0006] The purpose of the present invention is to solve the defects of the above-mentioned prior art and provide a dynamic solution and error compensation method for a gyroscope under complex vibrations. By analyzing various parameters in the mining process, a vibration transfer model of a near-bit while-drilling measurement system is constructed, the influence of various errors of the gyroscope and the accelerometer on the measurement results is analyzed, and the error model of the gyroscope and the accelerometer in the near-bit while-drilling measurement system is constructed. The empirical mode decomposition algorithm is used to realize the intelligent extraction of the motion characteristics of the near-bit while-drilling measurement system; the three-axis acceleration and three-axis angular velocity signals of the drill tool are collected to establish a dynamic continuous solution model of the three-dimensional attitude of the drill tool, the cone error compensation strategy of angular vibration under attitude solution and the rowing error compensation of linear vibration under velocity solution are analyzed, and a dynamic correction strategy for vibration errors is established.

[0007] The present invention adopts the following technical solution:

[0008] A method for dynamic solution and error compensation of a gyroscope under complex vibration comprises the following steps:

[0009] S1: Analyze the influence of wellbore structure, drilling tool type, drilling pressure, and drilling tool deadweight parameters on drill string vibration during mining, use Hamiltonian principle and finite element numerical simulation to complete the analysis of the coupled mechanical characteristics of drill string vibration, and construct the vibration transfer matrix between the drill string and the near-bit while-drilling measurement system. According to the vibration transfer matrix, the vibration mathematical model of the near-bit while-drilling measurement system is obtained, and the construction of the vibration transfer model of the near-bit while-drilling measurement system is completed.

[0010] S2: Analyze the influence of zero bias, installation error, scale factor and random measurement error of gyroscope and accelerometer on the measurement results, and construct the error model of gyroscope and accelerometer in the near-bit measurement while drilling system.

[0011] S3: Perform vibration quadratic error analysis based on the mathematical model constructed in S1, establish a high-order vibration error identification model, and use the empirical mode decomposition algorithm to realize the intelligent extraction of motion characteristics of the near-drill bit measurement while drilling system.

[0012] S4: Continuously collect the three-axis acceleration and three-axis angular velocity signals of the drilling tool, and establish a dynamic continuous solution model for the three-dimensional posture of the drilling tool through quaternion theory and Euler angle theory.

[0013] S5: Using the algorithm described in S3 to perform spectrum analysis on the angular vibration and linear vibration of the while drilling measurement system, a dynamic correction strategy for vibration errors is established to achieve dynamic calibration of the vibration error of the near-bit while drilling measurement system.

[0014] Among them, in step S1, the parameters that need to be collected include drilling pressure, drilling tool deadweight, drilling fluid properties, friction resistance and rotary table speed;

[0015] In step S2, a MEMS gyroscope is installed near the drill bit of the drill string;

[0016] In step S2, the dynamic equation of the MEMS gyroscope used in the driving and detecting axes can be described as a second-order differential equation, and its mathematical expression is:

[0017]

[0018] Where m is the equivalent mass of the driving axis and the detection axis; c x 、c y are the damping coefficients of the driving and detection modes, c xy and c yx are the coupling damping coefficients of the driving and detection modes respectively; k x , ky are the stiffness coefficients of the driving and detection modes respectively; k xy and k yx are the coupling stiffness coefficients of the driving and detection modes respectively; F 1 (t) is the driving mode excitation force, F 2 (t) is the feedback force of the detection mode; x and y represent the motion displacement of the driving axis and the detection axis, respectively; and represent the speed in the x and y directions respectively, and Respectively represent the acceleration in the x direction and the y direction; Ω z is the input angular velocity.

[0019] In step S2, the influence of zero bias, installation error, scale factor and random measurement error on the measurement result is analyzed, and the error model of the gyroscope and accelerometer in the near-bit while-drilling measurement system is completed. The mathematical expression of the model is:

[0020]

[0021] In the formula, w x 、w y 、w z are the output values ​​of the MEMS gyroscope x, y, and z axes, and is the zero bias drift of the MEMS gyroscope x, y, and z axes, K xx , K yy and K zz K is the scale factor of the MEMS gyroscope x, y, and z axes; xy , K xz They are the installation error coefficients of the x-axis deviating from the y-axis and the installation error coefficients of the x-axis deviating from the z-axis, K yz K is the installation error coefficient of the y-axis toward the z-axis, yx , K zx , K zy They are the installation error coefficient of the y-axis deviation to the x-axis, the installation error coefficient of the z-axis deviation to the x-axis, the installation error coefficient of the y-axis deviation to the z-axis, and the same as above; ω x ,ω y and ω z K is the value of x, y, and z axes after the dimension change of MEMS gyroscope; gxx , K gyy , K gzz is the gyroscope g sensitivity coefficient; g x , g y and g z are the output values ​​of the MEMS accelerometer on the x, y, and z axes;

[0022] In step S3, according to the mathematical model of step S1, the vibration quadratic error analysis is performed, and then a high-order vibration error identification model is established; the empirical mode decomposition algorithm is used to realize the intelligent extraction of the motion characteristics of the near-bit measurement while drilling system, and its expression is:

[0023]

[0024] Among them, x(t) is the time parameter sequence, I i (t) is the i-th intrinsic mode function obtained by empirical mode decomposition; R n (t) is the residual margin of the i-th stage obtained by empirical mode decomposition, which realizes the intelligent extraction of the motion characteristics of the near-bit measurement while drilling system.

[0025] In step S4, the collected three-axis acceleration and three-axis angular velocity signals of the drilling tool are used to establish a dynamic continuous solution model for the three-dimensional posture of the drilling tool through quaternion theory and Euler angle theory;

[0026] In step S5, the result of spectrum analysis of the angular vibration and linear vibration of the measurement while drilling system is performed using the empirical mode decomposition algorithm in step S3, and cone error compensation is used to complete the compensation of angular vibration in attitude solution. The differential equation of the rotation vector is simplified as follows:

[0027]

[0028] In the formula is the rotation vector, and ω is the angular velocity of the body.

[0029] In step S5, the angular vibration and linear vibration of the measurement while drilling system are subjected to spectrum analysis using the empirical mode decomposition algorithm in step S3, and rowing error compensation is used to complete the compensation of the linear vibration under speed solution. The rowing error compensation term formula is as follows:

[0030]

[0031] In the formula, Indicates the rowing error compensation amount; t m Represents the time within m sampling periods; represents acceleration; represents the Coriolis acceleration; Indicates speed; Represents angular velocity.

[0032] Beneficial effects of the present invention:

[0033] The present invention provides a dynamic solution and error compensation method for a gyroscope under complex vibration. The vibration transmission model of a near-drill bit measurement system is constructed by analyzing various parameters in the mining process; the influence of various errors of gyroscopes and accelerometers on the measurement results is analyzed, and the gyroscopes and accelerometers are directly installed near the drill bit. The MEMS inclinometer near the drill bit will be directly affected by the impact vibration generated by the rotation of the drill bit and the rock breaking of the drill bit, which will seriously affect the accuracy of the drilling trajectory measurement while drilling. It is necessary to construct an error model of the gyroscope and accelerometer in the near-drill bit measurement system while drilling, improve the measurement accuracy of the gyroscope, and use the empirical mode decomposition algorithm to realize the intelligent extraction of the motion characteristics of the near-drill bit measurement system while drilling; the three-axis acceleration and three-axis angular velocity signals of the drill tool are collected to establish a dynamic continuous solution model of the three-dimensional attitude of the drill tool, analyze the cone error compensation strategy of angular vibration under attitude solution and the rowing error compensation of linear vibration under velocity solution, and establish a dynamic correction strategy for vibration errors. The present invention improves the measurement accuracy of the MEMS gyroscope and completes the efficient mining of the gas layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of the steps of the present invention;

[0035] Figure 2 It is a schematic diagram of the working principle of the gyroscope of the present invention;

[0036] Figure 3 The average output angular velocity before and after the three-axis compensation of the present invention;

[0037] Figure 4(a) shows the output angular velocity before and after x-axis compensation;

[0038] Figure 4(b) shows the output angular velocity before and after y-axis compensation;

[0039] Figure 4(c) shows the output angular velocity before and after z-axis compensation. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figure 1 As shown, a method for dynamic solution and error compensation of a gyroscope under complex vibration of the present invention comprises the following steps:

[0042] S1: According to the parameters such as the wellbore structure and drilling tool type during the mining process, the influence of various factors on the vibration of the drill string is analyzed, and the vibration mathematical model of the near-bit while-drilling measurement system is obtained to realize the construction of the vibration transfer model of the near-bit while-drilling measurement system.

[0043] S2: Analyze the influence of zero bias, installation error, scale factor and random measurement error of gyroscope and accelerometer on the measurement results, and construct the error model of gyroscope and accelerometer in the near-bit measurement while drilling system.

[0044] S3: Perform vibration quadratic error analysis based on the mathematical model constructed in S1, establish a high-order vibration error identification model, and use the empirical mode decomposition algorithm to realize the intelligent extraction of motion characteristics of the near-drill bit measurement while drilling system.

[0045] S4: Continuously collect the three-axis acceleration and three-axis angular velocity signals of the drilling tool, and establish a dynamic continuous solution model for the three-dimensional posture of the drilling tool through quaternion theory and Euler angle theory.

[0046] S5: Using the algorithm described in S3 to perform spectrum analysis on the angular vibration and linear vibration of the while drilling measurement system, a dynamic correction strategy for vibration errors is established to achieve dynamic calibration of the vibration error of the near-bit while drilling measurement system.

[0047] Among them, in step S1, the parameters that need to be collected include drilling pressure, drilling tool deadweight, drilling fluid properties, friction resistance and rotary table speed;

[0048] In step S1, a mathematical model is constructed using the Hamiltonian principle. After the mathematical model is constructed, the parameter curve obtained by the Hamiltonian principle is input into the finite element numerical simulation model to obtain the coupled mechanical characteristics of the drill string vibration, thereby obtaining the vibration coupling characteristics between the drill string and the near-bit while-drilling measurement system, constructing a vibration transfer matrix, and completing the construction of the mathematical model.

[0049] In step S2, a MEMS gyroscope is installed near the drill bit of the drill string;

[0050] In step S2, the dynamic equation of the MEMS gyroscope used in the driving and detecting axes can be described as a second-order differential equation, and its mathematical expression is:

[0051]

[0052] m is the equivalent mass of the driving axis and the detection axis; c x 、c y are the damping coefficients of the driving and detection modes, c xy and c yx are the coupling damping coefficients of the driving and detection modes respectively; k x , k yare the stiffness coefficients of the driving and detection modes respectively; k xy and k yx are the coupling stiffness coefficients of the driving and detection modes respectively; F 1 (t) is the driving mode excitation force, F 2 (t) is the feedback force of the detection mode; x and y represent the motion displacement of the driving axis and the detection axis, respectively; and represent the speed in the x and y directions respectively, and Respectively represent the acceleration in the x direction and the y direction; Ω z is the input angular velocity.

[0053] In step S2, the influence of zero bias, installation error, scale factor and random measurement error on the measurement result is analyzed, and the error model of the gyroscope and accelerometer in the near-bit while-drilling measurement system is completed. The mathematical expression of the model is:

[0054]

[0055] In the formula, w x 、w y 、w z is the output value of the MEMS gyroscope x, y, and z axes, ω 0x ,ω 0y and ω 0z is the zero bias drift of the MEMS gyroscope x, y, and z axes, K xx , K yy and K zz K is the scale factor of the MEMS gyroscope x, y, and z axes; xy , K xy They are the installation error coefficients of the x-axis deviating from the y-axis and the installation error coefficients of the x-axis deviating from the z-axis, K yz K is the installation error coefficient of the y-axis toward the z-axis, yx , K zx , K zy They are the installation error coefficient of the y-axis deviation to the x-axis, the installation error coefficient of the z-axis deviation to the x-axis, and the installation error coefficient of the y-axis deviation to the z-axis; ω x ,ω y and ω z is the value of the x, y, and z axes after the dimension change of the MEMS gyroscope; g x , g y and g z are the output values ​​of the MEMS accelerometer on the x, y, and z axes;

[0056] In step S3, according to the mathematical model of step S1, the vibration quadratic error analysis is performed, and then a high-order vibration error identification model is established; the empirical mode decomposition algorithm is used to realize the intelligent extraction of the motion characteristics of the near-bit measurement while drilling system, and its expression is:

[0057]

[0058] Among them, x(t) is the time parameter sequence, I i (t) is the i-th intrinsic mode function obtained by empirical mode decomposition; R n (t) is the residual margin of the i-th stage obtained by empirical mode decomposition, which realizes the intelligent extraction of the motion characteristics of the near-bit measurement while drilling system.

[0059] In step S4, the collected three-axis acceleration and three-axis angular velocity signals of the drilling tool are used to establish a dynamic continuous solution model for the three-dimensional posture of the drilling tool through quaternion theory and Euler angle theory;

[0060] In step S5, the result of spectrum analysis of the angular vibration and linear vibration of the measurement while drilling system is performed using the empirical mode decomposition algorithm in step S3, and the cone error compensation is used to compensate the angular vibration under the attitude solution. The differential equation of the rotation vector is simplified as follows:

[0061]

[0062] In the formula is the rotation vector, and ω is the angular velocity of the body.

[0063] In step S5, the angular vibration and linear vibration of the measurement while drilling system are subjected to spectrum analysis using the empirical mode decomposition algorithm in step S3, and rowing error compensation is used to complete the compensation of the linear vibration under speed solution. The rowing error compensation term formula is as follows:

[0064]

[0065] In the formula, Indicates the rowing error compensation amount; t m Represents the time within m sampling periods; represents acceleration; represents the Coriolis acceleration; Indicates speed; Represents angular velocity.

[0066] In order to prove the feasibility of the invention patent method, an experiment was conducted to verify the method, using a rotational vibration test system as the experimental platform. The near-bit measuring sub was fixed on the experimental platform, and the well inclination measurement sensor in the measuring sub included a MEMS triaxial accelerometer and a triaxial gyroscope. Figure 2As shown, the working principle of the MEMS gyroscope is to sense angular velocity through the vibration of the object. When the mass block oscillates back and forth along the driving axis X, the Z axis has an angular velocity Ω input. According to the Coriolis force principle, the mass block will generate a Coriolis force along the detection axis Y, and then drive the mass block to move along the detection axis Y, so that the capacitance of the detection axis changes. The input angular velocity is obtained by converting the capacitance change. The measurement directions of the gravity acceleration component and the angular velocity component near the drill bit are respectively along the radial Z axis direction, the tangential X axis direction and the axial Y axis direction of the drill tool. The output angular rates of the X-axis, Y-axis and Z-axis are measured for 100ms respectively, and the measured experimental data are analyzed according to the process of the patented method of the present invention. The angular velocity output of the MEMS gyroscope after compensation according to this method is compared with the angular velocity output of the MEMS gyroscope without adding the error model, as shown in FIG. Figure 3 As shown in FIG. 1 , the average output angular rates before and after compensation of the three axes of X-axis, Y-axis and Z-axis are respectively -.032 and 0.15 for the X-axis; 2.13 and 0.27 for the Y-axis; and 2.21 and 0.62 for the Z-axis. The experimental data are plotted according to the process of the method of the present invention to obtain the curves of the three axes of X-axis, Y-axis and Z-axis before and after error compensation. The results are shown in FIG. Figure 4(a)-4(c) As shown in the figure, it can be seen that the measurement accuracy of the MEMS gyroscope is significantly improved after using the method of the present invention.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for dynamic solution and error compensation of a gyroscope under complex vibration, characterized in that , including the following steps: S1. According to the wellbore structure and drilling tool type parameters during the mining process, the influence of various parameters on the vibration of the drill string is analyzed, and the vibration mathematical model of the near-bit while-drilling measurement system is obtained to realize the construction of the vibration transfer model of the near-bit while-drilling measurement system; S2. Analyze the influence of the zero bias, installation error, scale factor and random measurement error of the gyroscope and accelerometer on the measurement results, and construct the error model of the gyroscope and accelerometer in the near-bit while-drilling measurement system. The mathematical expression of the error model is: In the formula, w x 、w y 、w z is the output value of the MEMS gyroscope x, y, and z axes, ω 0x ,ω 0y and ω 0z is the zero bias drift of the MEMS gyroscope x, y, and z axes, K xx , K yy and K zz K is the scale factor of the MEMS gyroscope x, y, and z axes; xy , K xz They are the installation error coefficients of the x-axis deviating from the y-axis and the installation error coefficients of the x-axis deviating from the z-axis, K yz K is the installation error coefficient of the y-axis toward the z-axis, yx , K zx , K zy They are the installation error coefficient of the y-axis deviation to the x-axis, the installation error coefficient of the z-axis deviation to the x-axis, and the installation error coefficient of the y-axis deviation to the z-axis; ω x ,ω y and ω z is the value of the x, y, and z axes after the dimension change of the MEMS gyroscope; g x , g y and g z is the output value of the MEMS accelerometer; Install a MEMS gyroscope near the drill bit on the drill string; The dynamic equation of the MEMS gyroscope used is described as a second-order differential equation in the driving and detecting axes, and its mathematical expression is: m is the equivalent mass of the driving axis and the detection axis; c x 、c y are the damping coefficients of the driving and detection modes, c xy and c yx are the coupling damping coefficients of the driving and detection modes respectively; k x , k y are the stiffness coefficients of the driving and detection modes respectively; k xy and k yx are the coupling stiffness coefficients of the driving and detection modes respectively; F1(t) is the driving mode excitation force, and F2(t) is the detection mode feedback force; x and y represent the motion displacements in the driving axis and the detection axis respectively; Ω z is the input angular velocity S3. Perform vibration quadratic error analysis based on the vibration mathematical model constructed in S1, establish a high-order vibration error identification model, and use the empirical mode decomposition algorithm to realize intelligent extraction of motion characteristics of the near-bit measurement while drilling system; Specifically, according to the vibration mathematical model in step S1, the vibration quadratic error analysis is performed, and then a high-order vibration error identification model is established. The empirical mode decomposition algorithm is used to realize the intelligent extraction of the motion characteristics of the near-bit while-drilling measurement system. The expression is: Among them, x(t) is the time parameter sequence, I i (t) is the i-th intrinsic mode function obtained by empirical mode decomposition, R n (t) is the residual margin of the ith stage obtained by empirical mode decomposition, which realizes the intelligent extraction of the motion characteristics of the near-bit measurement while drilling system; S4. Continuously collect the three-axis acceleration and three-axis angular velocity signals of the drilling tool, and establish a dynamic continuous solution model for the three-dimensional posture of the drilling tool through quaternion theory and Euler angle theory; S5. Using the empirical mode decomposition algorithm described in S3 to perform spectrum analysis on the angular vibration and linear vibration of the while drilling measurement system, a dynamic correction strategy for vibration errors is established to achieve dynamic calibration of the vibration error of the near-drill bit while drilling measurement system.

2. The method for dynamic solution and error compensation of a gyroscope under complex vibration according to claim 1, characterized in that: in, In step S1, the parameters include bit pressure, drilling tool deadweight, drilling fluid properties, friction and rotary table speed.

3. The method for dynamic solution and error compensation of a gyroscope under complex vibration according to claim 1, characterized in that: Step 1: Use the Hamiltonian principle to construct a vibration mathematical model, input the parameter curve obtained by the Hamiltonian principle into the finite element numerical simulation model, obtain the coupled mechanical characteristics of the drill string vibration, and thus obtain the vibration coupling characteristics between the drill string and the near-drill bit while-drilling measurement system, construct a vibration transfer matrix, and complete the construction of the vibration mathematical model.

4. The method for dynamic solution and error compensation of a gyroscope under complex vibration according to claim 1, characterized in that: Step S5 also includes using cone error compensation to compensate for angular vibration in attitude solution, and the differential equation of the rotation vector is simplified as follows: In the formula is the rotation vector, and ω is the angular velocity of the body.

5. The method for dynamic solution and error compensation of a gyroscope under complex vibration according to claim 1, characterized in that: In step S5, rowing error compensation is also used to complete the compensation of line vibration under speed solution. The rowing error compensation term formula is as follows: In the formula, Indicates the rowing error compensation amount; t m Represents the time within m sampling periods; represents acceleration; represents the Coriolis acceleration; Indicates speed; Represents angular velocity.

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