Magnetic flux data correction method based on attitude

Abstract

The invention discloses a posture-based magnetic flux data correction method, which comprises the following steps: S1) putting a crack-free calibration oil well pipeline into a detection device to obtain a calibration oil well pipeline magnetic flux change rate database; s2) continuously detecting a surrounding magnetic field by a magnetometer to obtain original data related to the magnetic field, and uploading the data to a core controller to obtain three-dimensional magnetic fluxes; s3) transmitting the obtained data into an upper computer of a ground station, and calculating the actual change rate of the three-dimensional magnetic flux in the pipeline; s4, after the scale factor, the relative attitude angle and the distance are solved, the orientation of the upper end of the small half part of the broken pipe relative to the inspection pipe is uniquely determined. According to the invention, the obtained information is corrected into the mapping relation of the information under the standard posture through the detection device entering in any posture, the detection accuracy is higher, the judgment of the broken pipe position is more accurate, the detection speed is higher, and the accuracy of broken pipe positioning is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of downhole pipe breakage detection technology, and specifically relates to an attitude-based magnetic flux data correction method. Background Technology

[0002] When a pipeline breaks downhole, it causes a change in the surrounding magnetic field. If the rate of change of magnetic flux is defined as the derivative of magnetic flux with respect to pipeline depth, then the rate of change of magnetic flux in the oil well pipeline at that location will change. The detection equipment identifies the break location promptly by comparing the difference between the rate of change of magnetic flux in the oil well pipeline and the calibrated rate of change. Furthermore, the measurement results can be obtained directly at the break point downhole and transmitted to a surface-based host computer via cable using a communication module. Therefore, the measurement results directly and quickly reflect the location of the break downhole pipeline, achieving accurate detection.

[0003] However, since the precise location of the upper part of the lower half of the broken tube and the actual orientation of the detection tube are unknown, the magnetometer cannot directly read effective magnetic field information from the environment to calculate the rate of change of magnetic flux, and therefore cannot be used to determine the location of the broken tube by comparing with the magnetic flux change rate database. Summary of the Invention

[0004] Objective of the Invention: To overcome the above shortcomings, the objective of this invention is to provide an attitude-based magnetic flux data correction method, establishing a mapping relationship that can correct information obtained by a detection device entering the ground in any attitude to information under a standard attitude. When used in conjunction with a detection device, this invention achieves higher detection accuracy, more precise determination of pipe breakage location, faster detection speed, lower cost, and simpler maintenance.

[0005] Technical Solution: To achieve the above objectives, this valve provides an attitude-based magnetic flux data correction method, including: S1): Place the testing device into the calibration oil well pipeline without cracks, and calculate the rate of change of magnetic flux at various points in the pipeline to obtain a database of magnetic flux change rates of calibration oil well pipeline. S2): The magnetometer continuously detects the surrounding magnetic field, obtains raw data about the magnetic field, and uploads the data to the core controller. The core controller, as a data processing unit, processes the raw data obtained by the magnetometer to obtain the magnetic flux in three dimensions. S3): Transmit the data obtained above to the host computer at the ground station, and calculate the actual rate of change of the three-dimensional magnetic flux in the pipeline using the formula. ; S4): Calculate the three sets of corresponding depths obtained from the above operations. and Substitute the values ​​into the corresponding formulas to solve for the scale factors. Relative attitude angle and distance Subsequently, the orientation of the upper part of the broken tube relative to the inspection tube was uniquely determined.

[0006] The magnetic flux data correction method based on attitude described in this invention, in step S1), calculates the rate of change of magnetic flux at various points in the pipeline to obtain a calibrated database of magnetic flux change rates in oil well pipelines, as detailed below: by Taking the first axis as an example, the other two axes are handled in the same way: (1) (2) In the formula, express On the axis The magnitude of the magnetic flux This indicates that the host computer received On the axis Rate of change of magnetic flux data Indicates the number received by the host computer The pipe depth corresponding to each magnetic flux data point. Indicates the number received by the host computer The actual value corresponding to each magnetic flux data point is calculated using the following formula: (3).

[0007] The present invention discloses an attitude-based magnetic flux data correction method, wherein the detection device extends underground from the upper half of the short pipe, at a distance of 100mm to 1000mm from the central axis of the lower half of the broken pipe, and the magnetic induction intensity generated by the lower half of the broken pipe is... The fragments are evenly distributed around the lower half of the broken tube from its upper (or lower) end to its lower (or upper) end at an angle.

[0008] The magnetic flux data correction method based on attitude described in this invention includes the following calculation process for the three dimensions of magnetic flux in step S2): S21): Assuming a right-handed system is established with the intersection of the central axis of the lower half of the broken pipe and the ground as the origin. A right-hand system was established with the point of entry of the detection tube as the origin. This is called the original system, in which the X-axis is defined as being parallel to... The two axes are collinear, and the other two axes are parallel; in particular, when the detection tube enters with a certain orientation relative to the original system, a right-handed system can be established. This is called a new system, in which the origin of the new system should coincide with the origin of the original system; S22): Assume the distance between the central axes of the upper and lower parts of the broken pipe is l ∈ (100mm, 1000mm), and the cross-sectional area of ​​the detection pipe is... Let be the area of ​​the magnetometer plane through which the i-axis passes, and let be the velocity at a constant speed. Inserted into the ground; S23): Rotate the coordinate system in the following order: around Axis rotation This wrap Axis rotation , around Axis rotation and stipulate The three rotation matrices are calculated as follows: Therefore It is the rotation matrix from the original frame to the new frame, which can be used to find the coordinate representation of the original vector in the new frame; Take magnetic induction intensity In the original system, it is orthogonally decomposed along the three axes into In the new system, it is orthogonally decomposed along the three axes into If at this time and If the measurements are taken separately when the distance between the detection tube and the lower half of the broken tube is the same, then the quantitative relationship presented by the formula (4) below should be satisfied: (7) In the formula, When calibrating the database, the formula for calculating the magnetic flux in each dimension is as follows: In actual measurement, the formula for calculating the magnetic flux in each dimension is: The quantitative relationship between and can be calculated from the above formulas (7), (8), and (9), as shown in formula (10): When the rate of change of magnetic flux is calculated by selecting continuous points, formula (10) can be equivalently transformed into formula (11). In actual measurements, since the distance between the detection tube and the lower half of the broken tube is unknown, it is generally impossible to substitute the values ​​for the same distance. and The value of has an effect that can be superimposed on the rotation matrix. The scaling factor is denoted as That is, the actual rotation matrix should be In formula (8), by substituting the magnetic flux data from the calibration database and the actual magnetic flux data at a certain distance at the same depth into three sets, the matrix can be solved. For this matrix, without a scale factor or When the sum of squares of the elements in the first row is 1, then the following can be determined: The value of can then be used to calculate the actual value. That is, the relatively primitive state of the new system.

[0009] The attitude-based magnetic flux data correction method described in this invention, based on the calibrated oil well pipeline magnetic flux change rate database in S1), fits a linear function of the magnetic flux change rate with respect to depth. ; Let the distance from the actual test tube to the centerline of the lower half of the broken tube be... The data substituted is at the distance If the subscript is specified, then it should have Therefore, we can solve it. Based on the previously obtained relative attitude information, the orientation of the upper part of the lower half of the broken tube relative to the inspection tube is uniquely determined.

[0010] As can be seen from the above technical solution, the present invention has the following beneficial effects: The magnetic flux data correction method based on attitude described in this invention corrects the information obtained by the detection device in any attitude to a mapping relationship of information under the standard attitude, resulting in higher detection accuracy, more precise determination of the broken pipe location, and faster detection speed. This effectively improves the accuracy of broken pipe location, while the user does not need to consider the ground entry attitude of the detection device, reducing the difficulty of use and facilitating promotion and application. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the attitude-based magnetic flux data correction method described in this invention. Figure 2 This is a partial installation diagram of the magnetometer and core controller in this invention; Figure 3 This is a schematic diagram showing the distribution of the interrupted pipe and three coordinate systems according to the present invention; the markings in the diagram are: 1. Coordinate system XYZ with the intersection of the central axis of the lower half of the interrupted pipe and the ground as the origin; 2. Coordinate system yz with the intersection of the central axis of the channel pipe and the ground as the origin; 3. Coordinate system y'z' after rotating the yz system around the origin; 4. The lower half of the interrupted pipe; 5. The upper half of the interrupted pipe; Figure 4 This is a data recording table of the actual three-dimensional magnetic flux change rate in this invention; Figure 5This is a data recording table for calibrating the rate of change of three-dimensional magnetic flux in this invention. Detailed Implementation

[0012] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments. Example

[0013] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0014] Example 1 Since the shape and location of the upper part of the broken tube are clear and the detection tube extends into the ground from the upper part of the broken tube, the maximum angle that the detection tube can form with the vertical direction is limited. Therefore, the slight influence of the angle on the magnitude of the magnetic induction intensity is ignored, but the influence of the angle on the magnitude of the magnetic flux is still retained.

[0015] The attitude-based magnetic flux data correction method described in this embodiment includes: S1): Place the testing device into the calibration oil well pipeline without cracks, and calculate the rate of change of magnetic flux at various points in the pipeline to obtain a database of magnetic flux change rates of calibration oil well pipeline. S2): Magnetometer 1 continuously detects the surrounding magnetic field, obtains raw data about the magnetic field, and uploads the data to core controller 2. Core controller 2, as a data processing unit, processes the raw data obtained by magnetometer 1 to obtain magnetic flux in three dimensions. S3): Transmit the data obtained above to the host computer at the ground station, and calculate the actual rate of change of the three-dimensional magnetic flux in the pipeline using the formula. Some data records are as follows Figure 3 Table 1; The three-dimensional magnetic flux change rate at a distance of 200 mm from the broken tube under the same priest was read from the calibration database, such as... Figure 4 Table 2; S4): Calculate the three sets of corresponding depths obtained from the above operations. and Substitute the values ​​into the corresponding formulas to solve for the scale factors. Relative attitude angle and distance Subsequently, the orientation of the upper part of the broken tube relative to the inspection tube was uniquely determined.

[0016] It should be noted that the relative depth mentioned above refers to the distance the inspection device passes through the broken tube.

[0017] In this embodiment, S1) calculates the rate of change of magnetic flux at various points in the pipeline to obtain a database of calibrated magnetic flux change rates for oil well pipelines, as detailed below: by Taking the first axis as an example, the other two axes are handled in the same way: (1) (2) In the formula, express On the axis The magnitude of the magnetic flux This indicates that the host computer received On the axis Rate of change of magnetic flux data Indicates the number received by the host computer The pipe depth corresponding to each magnetic flux data point. Indicates the number received by the host computer The actual value corresponding to each magnetic flux data point is calculated using the following formula: (3).

[0018] In this embodiment, the detection device extends underground from the upper half of the short pipe, at a distance of 100mm to 1000mm from the central axis of the lower half of the broken pipe, and the magnetic induction intensity generated by the lower half of the broken pipe... The fragments are evenly distributed around the lower half of the broken tube from its upper (or lower) end to its lower (or upper) end at an angle.

[0019] In the detection device, the volume of magnetometer 1 is relatively small compared to the detection space, therefore its magnetic flux in the three dimensions is... Based on the magnetic induction intensity at this point Perform calculations. The area of ​​the magnetometer plane through which the axis passes.

[0020] In this embodiment, preferably, the calculation process of the magnetic flux in the three dimensions of S2) is as follows: S21): Assuming a right-handed system is established with the intersection of the central axis of the lower half of the broken pipe and the ground as the origin. A right-hand system was established with the point of entry of the detection tube as the origin. This is called the original system, in which the X-axis is defined as being parallel to... The two axes are collinear, and the other two axes are parallel; in particular, when the detection tube enters with a certain orientation relative to the original system, a right-handed system can be established. This is called a new system, in which the origin of the new system should coincide with the origin of the original system; S22): Assume the distance between the central axes of the upper and lower parts of the broken pipe is l ∈ (100mm, 1000mm), and the cross-sectional area of ​​the detection pipe is... for The area of ​​the magnetometer plane through which the shaft passes, and the detection tube moving at a constant speed. Inserted into the ground; For example: The detection tube moves at a constant speed Inserted underground, sampling time interval .

[0021] S23): Rotate the coordinate system in the following order: around Axis rotation This wrap Axis rotation , around Axis rotation and stipulate The three rotation matrices are calculated as follows: Therefore It is the rotation matrix from the original frame to the new frame, which can be used to find the coordinate representation of the original vector in the new frame; Take magnetic induction intensity In the original system, it is orthogonally decomposed along the three axes into In the new system, it is orthogonally decomposed along the three axes into If at this time and If the measurements are taken separately when the distance between the detection tube and the lower half of the broken tube is the same, then the quantitative relationship presented by the formula (4) below should be satisfied: In the formula, ; When calibrating the database, the formula for calculating the magnetic flux in each dimension is as follows: In actual measurement, the formula for calculating the magnetic flux in each dimension is: The above formulas (7), (8), and (9) can be used to calculate the following: and The quantitative relationship is shown in formula (10): When continuous points are selected to solve for the rate of change of magnetic flux, formula (10) can be equivalently transformed into formula (11). In actual measurements, since the distance between the detection tube and the lower half of the broken tube is unknown, it is generally impossible to substitute the values ​​for the same distance. and The value of has an effect that can be superimposed on the rotation matrix. The scaling factor is denoted as That is, the actual rotation matrix should be In formula (8), by substituting the magnetic flux data from the calibration database and the actual magnetic flux data at a certain distance at the same depth into three sets, the matrix can be solved. For this matrix, without a scale factor or When the sum of squares of the elements in the first row is 1, then the following can be determined: The value of can then be used to calculate the actual value. That is, the relatively primitive state of the new system.

[0022] In this embodiment, based on the database of magnetic flux change rate calibrated in S1), a linear function of the magnetic flux change rate with respect to depth is fitted. ; Let the distance from the actual test tube to the centerline of the lower half of the broken tube be... The data substituted is at the distance If the subscript is specified, then it should have Therefore, we can solve it. Based on the previously obtained relative attitude information, the orientation of the upper part of the lower half of the broken tube relative to the inspection tube is uniquely determined.

[0023] In this embodiment, S4) involves processing the three sets of corresponding depths obtained from the above calculations. and Substitute the values ​​into the corresponding formulas to solve for the scale factors. Relative attitude angle and distance Subsequently, the orientation of the upper end of the broken section of the tube relative to the inspection tube is uniquely determined, and its specific calculation formula is as follows: have to The scale factor is obtained by taking the square root of the sum of the squares of the elements in the first row. Therefore, the rotation matrix The solution can be obtained sequentially. Based on a database calibrated through multiple measurements on the ground, we fitted a function of the rate of change of magnetic flux with respect to depth. ,in The unit is mm, according to the formula It can be calculated At this point, the unique orientation of the upper part of the lower half of the short tube can be determined.

[0024] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A magnetic flux data correction method based on attitude, characterized in that: include: S1): Place the testing device into the calibration oil well pipeline without cracks, and calculate the rate of change of magnetic flux at various points in the pipeline to obtain a database of magnetic flux change rates of calibration oil well pipeline. S2): Magnetometer (1) continuously detects the surrounding magnetic field, obtains the raw data of the magnetic field, and uploads the data to the core controller (2). The core controller (2) processes the raw data obtained by magnetometer (1) as a data processing unit to obtain the magnetic flux in three dimensions. S3): Transmit the data obtained above to the host computer at the ground station, and calculate the actual rate of change of the three-dimensional magnetic flux in the pipeline using the formula. ; S4): Calculate the three sets of corresponding depths obtained from the above operations. and Substitute the values ​​into the corresponding formulas to solve for the scale factors. Relative attitude angle and distance Subsequently, the orientation of the upper part of the broken tube relative to the inspection tube was uniquely determined.

2. The attitude-based magnetic flux data correction method according to claim 1, characterized in that: In step S1), the rate of change of magnetic flux at various points in the pipeline is calculated to obtain a database of magnetic flux change rates for calibrated oil well pipelines, as detailed below: by Taking the first axis as an example, the other two axes are handled in the same way: In the formula, express On the axis The magnitude of the magnetic flux This indicates that the host computer received On the axis Rate of change of magnetic flux data Indicates the number received by the host computer The pipe depth corresponding to each magnetic flux data point. Indicates the number received by the host computer The actual value corresponding to each magnetic flux data point is calculated using the following formula: (3)。 3. The magnetic flux data correction method based on attitude according to claim 1, characterized in that: The detection device extends underground from the upper half of the short pipe, at a distance of 100mm to 1000mm from the central axis of the lower half of the broken pipe, and the magnetic induction intensity generated by the lower half of the broken pipe... The fragments are evenly distributed around the lower half of the broken tube from its upper (or lower) end to its lower (or upper) end at an angle.

4. The attitude-based magnetic flux data correction method according to claim 3, characterized in that: The calculation process for the magnetic flux in the three dimensions of S2 is as follows: S21): Assuming a right-handed system is established with the intersection of the central axis of the lower half of the broken pipe and the ground as the origin. A right-hand system was established with the point of entry of the detection tube as the origin. This is called the original system, in which the X-axis is defined as being parallel to... The two axes are collinear, and the other two axes are parallel; in particular, when the detection tube enters with a certain orientation relative to the original system, a right-handed system can be established. This is called a new system, in which the origin of the new system should coincide with the origin of the original system; S22): Assume the distance between the central axes of the upper and lower parts of the broken pipe is l ∈ (100mm, 1000mm), and the cross-sectional area of ​​the detection pipe is... Let be the area of ​​the magnetometer plane through which the i-axis passes, and let be the velocity at a constant speed. Inserted into the ground; S23): Rotate the coordinate system in the following order: around Axis rotation This wrap Axis rotation , around Axis rotation and stipulate The three rotation matrices are calculated as follows: Therefore It is the rotation matrix from the original frame to the new frame, which can be used to find the coordinate representation of the original vector in the new frame; Take magnetic induction intensity In the original system, it is orthogonally decomposed along the three axes into In the new system, it is orthogonally decomposed along the three axes into If at this time and If the measurements are taken separately when the distance between the detection tube and the lower half of the broken tube is the same, then the quantitative relationship presented by the formula (7) below should be satisfied: In the formula, ； When calibrating the database, the formula for calculating the magnetic flux in each dimension is as follows: In actual measurement, the formula for calculating the magnetic flux in each dimension is: The above formulas (7), (8), and (9) can be used to calculate the following: and The quantitative relationship is shown in formula (10): When continuous points are selected to solve for the rate of change of magnetic flux, formula (10) can be equivalently transformed into formula (11). In actual measurements, since the distance between the detection tube and the lower half of the broken tube is unknown, it is generally impossible to substitute the values ​​for the same distance. and The value of has an effect that can be superimposed on the rotation matrix. The scaling factor is denoted as That is, the actual rotation matrix should be In formula (11), by substituting the magnetic flux data from the calibration database and the actual magnetic flux data at a certain distance at the same depth into three sets, the matrix can be solved. For this matrix, without a scale factor or When the sum of squares of the elements in the first row is 1, then the following can be determined: The value of can then be used to calculate the actual value. That is, the relatively primitive state of the new system.

5. The attitude-based magnetic flux data correction method according to claim 4, characterized in that: Based on the database of magnetic flux change rate in the calibrated oil well pipeline in S1), a linear function of the magnetic flux change rate with respect to depth is fitted. ; Let the distance from the actual test tube to the centerline of the lower half of the broken tube be... The data substituted is at the distance If the subscript is specified, then it should have Therefore, we can solve it. Based on the previously obtained relative attitude information, the orientation of the upper part of the lower half of the broken tube relative to the inspection tube is uniquely determined.

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