Method and device for correcting magnetic azimuth angle

Abstract

The invention discloses a method and a device for correcting a magnetic azimuth angle. The method comprises the following steps: acquiring data of a group of measuring points measured by the magnetic measurement-while-drilling instrument; the data of the measurement points comprises fluxgate readings in three directions of an instrument measurement coordinate system; the fluxgate reading of each measuring point in the radial direction of the drill column is corrected; correcting the fluxgate reading of each measuring point subjected to radial correction along the axial direction of the drill stem, and calculating an azimuth angle according to the fluxgate reading of each measuring point subjected to axial correction; according to the azimuth angle calculated by the fluxgate reading after the axial direction correction of each measurement point, the axial magnetic interference intensity value closest to the geomagnetic field is calculated by using the principle of correcting the axial magnetic interference by multiple measurement points; and the azimuth angle of each measuring point after final correction is calculated. The method is easy and convenient to operate and stable in algorithm, the azimuth angle measurement precision can be more effectively improved, meanwhile, the length of the non-magnetic drill collar is reduced, and the drilling cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling equipment technology, and in particular to a method and apparatus for magnetic azimuth correction. Background Technology

[0002] Magnetic Measurement While Drilling (MWD) is a primary measuring instrument used in oil and gas exploration and development to control wellbore trajectory. It uses six-axis sensors (a three-axis gravity accelerometer and a three-axis fluxgate) to measure trajectory parameters such as inclination angle, azimuth angle, and tool face, thereby providing accurate wellbore trajectory information for drilling operations.

[0003] However, due to the limitations imposed by environmental factors such as temperature, geomagnetic field, and drill string magnetization, the accuracy of azimuth measurement of the three-axis fluxgate sensor is severely affected. If the deviation is not corrected in time, it can easily cause problems such as missing the target or wellbore collision.

[0004] In the existing technology, methods such as improving temperature characteristics and correcting magnetic interference have been used to correct azimuth measurement results. Although these methods have achieved certain results, they mostly focus on correcting single-point measurement results, resulting in limited correction effects and complex calculations in practice. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a method and apparatus for magnetic azimuth correction that overcomes or at least partially solves the above problems.

[0006] In a first aspect, embodiments of the present invention provide a method for magnetic azimuth correction, comprising:

[0007] Obtain data from a set of measurement points measured by the magnetic measurement while drilling instrument; the data for each measurement point includes fluxgate readings in three directions in the instrument's measurement coordinate system;

[0008] For each measurement point, the fluxgate reading of the measurement point along the radial direction of the drill string in the instrument's measurement coordinate system is corrected.

[0009] For each measurement point after radial correction, the fluxgate reading of the measurement point along the drill string axis in the instrument measurement coordinate system is corrected, and the azimuth angle is calculated based on the fluxgate reading of each measurement point after axial correction.

[0010] Based on the azimuth angle calculated from the fluxgate readings of each measurement point after axial direction correction, the axial magnetic interference intensity value at the point closest to the Earth's magnetic field is calculated using the improved indirect multi-measurement point correction axial magnetic interference principle.

[0011] Based on the axial magnetic interference value of the measurement point closest to the geomagnetic field, the final corrected azimuth angle of each measurement point is calculated.

[0012] In one embodiment, the fluxgate readings of the measurement points along the radial direction of the drill string in the instrument's measurement coordinate system are corrected, including:

[0013] The magnetic interference of the magnetic hotspots causing radial interference on the magnetic measurement while drilling instrument, and the radially corrected fluxgate reading are calculated using the following formula:

[0014] (B X1 -M X ) 2 +(B Y1 -M Y ) 2 = (B X2 -M X ) 2 +(B Y2 -M Y ) 2 =…=(B Xn -M X ) 2 +(B Yn -M Y ) 2 ;

[0015] B XC =B X -M X ;

[0016] B YC =B Y -M Y ;

[0017] In the above formula, n represents the nth measurement point, B Xn B Yn B is the fluxgate reading at the nth measurement point along the radial direction of the drill string; XC and B YC This is the fluxgate reading after radial correction.

[0018] In one embodiment, the fluxgate readings of the measurement points along the drill string axial direction in the instrument's measurement coordinate system are corrected, and the azimuth angle is calculated based on the axially corrected fluxgate readings of each measurement point, including:

[0019] For each measurement point, the axial magnetic flux density is calculated using the local magnetic field strength and magnetic inclination, and the corrected first axial magnetic flux density component is obtained in reverse.

[0020] The first corrected azimuth angle AZI_Short is solved using the first axial magnetic induction intensity component;

[0021] The error E between the magnetic field strength calculated by the magnetic field measurement while drilling instrument and the Earth's magnetic field strength, and the axial fluxgate value B. ZM The quadratic relationship between them is used to find the minimum value of E by using the extreme value solution method. The axial fluxgate reading at the minimum value of E is then determined as the corrected second axial magnetic induction intensity component.

[0022] Substitute the second axial magnetic flux density component into the azimuth calculation formula to obtain the second corrected azimuth angle AZI_indirect;

[0023] The first corrected azimuth angle and the second corrected azimuth angle are weighted and calculated to obtain the azimuth angle AZI after axial direction correction. cal .

[0024] In one embodiment, the first axial magnetic flux density component is calculated using the following formula:

[0025] B V =B t cosDIP;

[0026] B N =B t sinDIP;

[0027] B zc =B t cosDIPcosAZIcosINC+B t cosDIPcosINC

[0028] In the above formula, B zc B is the first axial magnetic induction component; N B represents the horizontal component of the local geomagnetic field, in μT. V is the vertical component of the local geomagnetic field, in μT; DIP is the magnetic inclination, in °; B t B is the magnetic flux density of the Earth's magnetic field, measured in μT. ZC 1. axial magnetic flux density component, unit μT; AZI is the corrected azimuth angle;

[0029] The formula for calculating the first corrected azimuth angle AZI_Short is:

[0030] HSG is the tool face angle; INC is the well inclination angle.

[0031] In one embodiment, the azimuth calculation formula is:

[0032]

[0033] In one embodiment, the first corrected azimuth angle and the second corrected azimuth angle are weighted and calculated to obtain the azimuth angle AZI after axial direction correction. cal ,include:

[0034] Calculate AZI using the following formula cal :

[0035]

[0036] In one embodiment, based on the azimuth angle calculated from the fluxgate readings of each measurement point in a set of measurement points after axial direction correction, the axial magnetic interference intensity value closest to the geomagnetic field measurement point is calculated using the improved indirect multi-measurement point correction axial magnetic interference principle, including:

[0037] Solve for the vertical and horizontal components of the magnetic field measured by the magnetic field measuring instrument at N measurement points, and the variance σ of the local geomagnetic field strength in the vertical and horizontal directions:

[0038]

[0039] According to the extreme value solution method, the above equation is calculated by partial differential equation to obtain:

[0040]

[0041] The azimuth angle AZI is calculated by using the stochastic gradient descent method to obtain the fluxgate readings of each measurement point after axial direction correction. cal Using ΔB as the initial value, we solve the above equation. Z If convergence occurs, or the number of iterations reaches the preset upper limit, then calculate ΔB at this point. Z , which is the axial magnetic interference intensity value at the location closest to the Earth's magnetic field.

[0042] In one embodiment, the final corrected azimuth angle of each measurement point is calculated based on the axial magnetic interference value at the location closest to the Earth's magnetic field, including:

[0043] Based on the axial magnetic interference value of the measurement point closest to the geomagnetic field, the difference between the fluxgate reading along the axial direction of the drill string and the axial interference value is calculated for each measurement point, and the corrected fluxgate reading in the axial direction is obtained for each measurement point.

[0044] Substitute the axial fluxgate readings and the radial fluxgate readings of each measurement point into the azimuth calculation formula to calculate the final corrected azimuth of each measurement point.

[0045] Secondly, embodiments of the present invention provide a magnetic azimuth correction device, comprising:

[0046] The acquisition module is used to obtain data from a set of measurement points measured by the magnetic drilling instrument; the data for each measurement point includes fluxgate readings in three directions in the instrument's measurement coordinate system;

[0047] The radial correction module is used to correct the fluxgate reading of each measurement point along the radial direction of the drill string in the instrument's measurement coordinate system for each measurement point.

[0048] The axial correction module is used to correct the fluxgate reading of each measurement point along the drill string axis in the instrument's measurement coordinate system after radial correction, and calculate the azimuth angle based on the fluxgate reading after axial correction for each measurement point. Based on the azimuth angle calculated from the fluxgate readings after axial correction for each measurement point in the set of measurement points, the axial magnetic interference intensity value at the point closest to the Earth's magnetic field is calculated using the improved indirect multi-measurement point correction principle. Based on the axial magnetic interference value at the measurement point closest to the Earth's magnetic field, the final corrected azimuth angle of each measurement point is calculated.

[0049] Thirdly, embodiments of the present invention provide a computing device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the magnetic azimuth correction method as described above.

[0050] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned method for magnetic azimuth correction.

[0051] Fifthly, embodiments of the present invention provide a computer program product, the computer program product including a computer program, which, when executed by a processor, implements the magnetic azimuth correction method as described above.

[0052] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0053] The magnetic azimuth correction method provided in this embodiment of the invention uses both radial and axial fluxgate readings from a single measuring point for correction, and also utilizes an improved indirect multi-measuring-point correction principle for axial magnetic interference. This achieves indirect magnetic interference correction at multiple measuring points, resulting in the final corrected azimuth angle. The wellbore trajectory obtained by inclination calculation using the corrected azimuth angle from this embodiment is closer to the actual wellbore trajectory. The single-measuring-point and multi-measuring-point indirect magnetic interference correction methods provided in this embodiment are simple to operate, have stable algorithms, and can more effectively improve the measurement accuracy of the azimuth angle. Simultaneously, they reduce the length of the non-magnetic drill collar, thereby lowering drilling costs.

[0054] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0055] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0056] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0057] Figure 1 This is a flowchart of the magnetic azimuth correction method in an embodiment of the present invention;

[0058] Figure 2 This is a diagram showing the relationship between the geographic coordinate system and the measurement coordinate system in an embodiment of the present invention;

[0059] Figure 3 This is a flowchart illustrating the correction of the fluxgate reading of the measurement point along the drill string axial direction in the instrument's measurement coordinate system, as described in this embodiment of the invention.

[0060] Figure 4 This is a schematic diagram illustrating the relationship between the Earth's magnetic field and the measured fluxgate magnetic field in an embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram of the single-point calibration principle in an embodiment of the present invention;

[0062] Figure 6 This is a schematic diagram of the improved indirect multi-measurement point correction of axial magnetic interference in an embodiment of the present invention;

[0063] Figure 7 This is a diagram showing the relationship between multi-point indirect correction, single-point indirect correction, and the true azimuth angle in an embodiment of the present invention.

[0064] Figure 8 This is a schematic diagram of the magnetic azimuth correction device in an embodiment of the present invention. Detailed Implementation

[0065] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0066] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0067] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0068] This invention provides a method for magnetic azimuth correction, referring to... Figure 1 As shown, it includes:

[0069] S11. Obtain data from a set of measurement points measured by the magnetic drilling instrument; the data for each measurement point includes fluxgate readings in three directions in the instrument's measurement coordinate system;

[0070] S12. For each measurement point, the fluxgate reading of the measurement point along the radial direction of the drill string in the instrument measurement coordinate system is corrected respectively;

[0071] S13. For each measurement point after radial correction, the fluxgate reading of the measurement point along the drill string axis in the instrument measurement coordinate system is corrected, and the azimuth angle is calculated based on the fluxgate reading of each measurement point after axial correction.

[0072] S14. Based on the azimuth angle calculated from the fluxgate readings of each measurement point after axial direction correction, the axial magnetic interference intensity value at the point closest to the Earth's magnetic field is calculated using the improved indirect multi-measurement point correction axial magnetic interference principle.

[0073] S15. Calculate the final corrected azimuth angle of each measurement point based on the axial magnetic interference value of the measurement point closest to the geomagnetic field.

[0074] The magnetic azimuth correction method provided in this embodiment of the invention utilizes both radial and axial fluxgate readings from a single measuring point for correction, and also leverages an improved indirect multi-measuring-point correction principle for axial magnetic interference. This achieves indirect magnetic interference correction at multiple measuring points, yielding the final corrected azimuth angle. The wellbore trajectory obtained by inclination calculation using the corrected azimuth angle from this embodiment is closer to the actual wellbore trajectory. The single-measuring-point and multi-measuring-point indirect magnetic interference correction methods provided in this embodiment are simple to operate, have stable algorithms, and can more effectively improve the measurement accuracy of the azimuth angle. Simultaneously, they reduce the length of the non-magnetic drill collar, lowering drilling costs. For ease of understanding, a brief explanation of the coordinate system related to the magnetic azimuth measuring instrument is provided first.

[0075] Reference Figure 2 As shown, the calculation of well inclination angle, tool face, and azimuth angle of the magnetic drilling measurement instrument is based on the geographic coordinate system "Northeast Sky" (ENU) XYZ and the drill string's custom measurement coordinate system (xyz). The drill string's axis and drilling direction are defined as the measurement instrument's z-axis, the tool face normal direction is defined as the x-axis, and the y-axis is orthogonal to the x-axis and z-axis, forming a right-hand rectangular coordinate system.

[0076] The relationship between geographic coordinate systems and instrumental measurement coordinate systems is as follows: Figure 2 As shown in the figure, plane H is the horizontal plane, plane P is the radial plane of the measurement while drilling, INC is the well inclination angle, AZI is the azimuth angle, HSG is the tool face angle of the magnetic measurement while drilling instrument, and the Z direction is the drilling direction.

[0077] Based on the principle of wireless drilling measurement, the formula for calculating the azimuth angle is as follows:

[0078]

[0079] The above Bx, By, and Bz are fluxgate readings.

[0080] In one embodiment, in step S12 above, the correction of the fluxgate readings of the measurement points along the radial direction of the drill string in the instrument measurement coordinate system can be achieved in the following manner:

[0081] The magnetic interference of the magnetic hotspots causing radial interference on the magnetic measurement while drilling instrument, and the radially corrected fluxgate reading are calculated using the following formula:

[0082] (B X1 -M X ) 2 +(B Y1 -M Y ) 2 = (B X2 -M X ) 2 +(B Y2 -MY ) 2 =…=(B Xn -M X ) 2 +(B Yn -M Y ) 2 ; Formula (2)

[0083] B XC =B X -M X ; Formula (3)

[0084] B YC =B Y -M Y ; Formula (4)

[0085] In the above formula, n represents the nth measurement point, and B Xn B Yn B is the fluxgate reading at the nth measurement point along the radial direction of the drill string; XC and B YC This is the fluxgate reading after radial correction.

[0086] In step S12 above, the principle of radial magnetic interference correction is as follows: when the drill string is rotated at the same well depth, the magnetic force measurement instrument rotates along the Z-axis and continuously or discretely records the measurement data. The radial magnetic interference rotates with the drill string and remains stationary relative to the instrument coordinate system. The direction and magnitude of the magnetic interference remain unchanged.

[0087] Taking three measurement points as an example, the drill string is rotated at the same well depth, and the magnetic measurement while drilling instrument rotates along the Z-axis to discretely record the data of the three measurement points: (B X1 B Y1 B Z1 (B) X2 B Y3 B Z2 (B) X3 B Y3 B Z3 Assume B XC B YC B ZC The fluxgate reading after correction for each measurement point is given, in Tesla. Mx and My represent the magnetic hotspots (the magnetic measurement while drilling instrument is mounted in the drill string, and the magnetic hotspots are in the drill string, which will cause magnetic interference to the wireless measurement while drilling instrument), also in Tesla. Mx and My are calculated by following formulas 5, 3, and 4 in that order. x M Y B XC B YC .

[0088] (BX1 -M X ) 2 +(B Y1 -M Y ) 2 = (B X2 -M X ) 2 +(B Y2 -M Y ) 2 = (B X3 -M X ) 2 +(B Y3 -M Y ) 2 Formula (5)

[0089] B XC =B X -M X Formula (3)

[0090] B YC =B Y -M Y Formula (4)

[0091] In one embodiment, in step S13 above, the fluxgate reading of the measurement point along the drill string axial direction in the instrument measurement coordinate system is corrected, referring to... Figure 3 As shown, this can be achieved in the following ways:

[0092] S31. For each measurement point, the axial magnetic induction intensity is calculated using the local magnetic field strength and magnetic inclination angle, and the first axial magnetic induction intensity component after correction is obtained in reverse.

[0093] This step involves short-collar calibration for a single measurement point.

[0094] The principle of short drill collar correction is to calculate the axial magnetic induction intensity using the local magnetic field strength and magnetic inclination, then inversely calculate the axial magnetic induction intensity component Bzc, and finally use the calculated axial magnetic induction intensity component to solve for the azimuth angle. Specifically, the first axial magnetic induction intensity component can be calculated using the following formula:

[0095] B V =B t cosDIP; formula (6)

[0096] B N =B t sinDIP; formula (7)

[0097] B zc =B t cosDIPcosAZIcosINC+Bt cosDIPcosINC formula (8)

[0098] In the above formula, B zc B is the first axial magnetic induction component; N B represents the horizontal component of the local geomagnetic field, in μT. V is the vertical component of the local geomagnetic field, in μT; DIP is the magnetic inclination, in °; B t B is the magnetic flux density of the Earth's magnetic field, measured in μT. ZC λ represents the axial magnetic flux density component, in μT; AZI is the corrected azimuth angle.

[0099] S32. Solve for the first corrected azimuth angle AZI_Short using the first axial magnetic induction intensity component;

[0100] The formula for calculating the first corrected azimuth angle AZI_Short is:

[0101] S33. The error E between the magnetic field strength calculated by the magnetic drilling measurement instrument and the Earth's magnetic field strength, and the axial fluxgate value B. ZM The quadratic relationship between them is used to find the minimum value of E by using the extreme value solution method. The axial fluxgate reading at the minimum value of E is then determined as the corrected second axial magnetic induction intensity component.

[0102] Step S33 involves indirect calibration of a single measuring point.

[0103] Reference Figure 4 As shown, let the Earth's gravitational field be G, and the accelerometer component be G. X G Y G Z The Earth's magnetic field strength is B, and the magnetic field strength calculated by the magnetic inclinometer is B. C B C The error between B and B is E, and its direction is parallel to the wellbore axis. The fluxgate component is B. XM B YM B ZM B ZM This is axial magnetic interference.

[0104] B C = (B XM +B YM +B ZM ) 1 / 2 Formula (10)

[0105] G = (G X 2 +G Y 2+G Z 2 ) 1 / 2 Formula (11)

[0106] The angle between the magnetic field strength BC and the gravitational field strength G, calculated by the magnetic inclinometer, is θ, which is derived using the dot product rule:

[0107] θ=cos -1 (B XM ·G X +B YM ·G Y +B ZM ·G Z ) Formula (12)

[0108] The angle between the local magnetic field strength and the gravitational field strength G is known as θ0:

[0109] θ0=90-β Formula (13)

[0110] According to the Law of Cosines, we can obtain B. C The absolute value of the difference between B and:

[0111] E = (B C 2 +B 2 -2B C ·B·cos(θ-θ0)) 1 / 2 Formula (14)

[0112] According to Formula 14 above, E is related to the axial fluxgate value B. ZM The relationship is quadratic. Using the extremum solution method, the final corrected axial fluxgate reading B is obtained when E reaches its minimum value. ZC (i.e., the second axial magnetic induction component), refer to Figure 4 and Figure 5 As shown, when E reaches its minimum value, that is, when B... ZC The component of the local magnetic field along the wellbore axis is closest to the local magnetic field.

[0113] S34. Substitute the second axial magnetic induction intensity component into the azimuth calculation formula to obtain the second corrected azimuth angle AZI_indirect;

[0114] Axial magnetic interference M Z =B Z -B ZC Using formula (1), B ZC As B Z Substitute the values ​​into the equation to solve for the final correction value AZI_indirect.

[0115]

[0116] S35. Perform a weighted calculation on the first corrected azimuth angle and the second corrected azimuth angle to obtain the azimuth angle AZI after axial direction correction. cal .

[0117] For example, AZI can be calculated using the following weighted formula. cal :

[0118]

[0119] In one embodiment, the principle of the improved indirect multi-point measurement correction for axial magnetic interference in step S14 above is briefly explained as follows:

[0120] Reference Figure 6 As shown, Figure 6 The horizontal division of the geomagnetic field in the middle horizontal axis B N The vertical axis represents the vertical component B of the magnetic field. V The reference point represents the local actual magnetic field strength, and the discrete points on the continuous line represent the measured magnetic field strength under the influence of magnetic interference in different axes.

[0121] The horizontal component B of the magnetic field strength calculated by the magnetic inclinometer. NM and vertical component B VM It can be represented by the vector dot product of the gravitational field and the magnetic field:

[0122]

[0123] B VM = (B C 2 -B NM 2 ) 1 / 2 Formula (17)

[0124] B ZC The axial magnetic interference intensity ΔB is the projection of the local magnetic field strength onto the axis of the magnetic inclinometer. Z It can be expressed as:

[0125] ΔB Z =B ZM -B ZC Formula (18)

[0126] Variation in axial magnetic disturbance intensity ΔB Z Value, axial fluxgate reading B ZM As the changes occur, different measured horizontal and vertical components of the magnetic field can be obtained, such as... Figure 6 As shown, B corresponds to the discrete point closest to the reference point. ZM It can be considered as the component of the geomagnetic field in the direction of the wellbore axis, and the axial magnetic interference at this time is the real magnetic interference.

[0127] Assuming there are N measuring points in a set of measuring points, the axial magnetic field at the i-th measuring point can be expressed as follows:

[0128] B ZC (i)=B ZM (i)-ΔB Z Formula (19)

[0129] The vertical and horizontal components of the measured magnetic field at the i-th measuring point can be expressed as follows:

[0130]

[0131] The variance of the magnetic field calculated by the magnetic inclinometer at N measuring points, compared with the local reference magnetic field (BNM(i), BVM(i)) and the geomagnetic field strength (BN, BV), can be expressed as:

[0132]

[0133] In one embodiment, λ = 0.02 is taken, and L2 correction is added so that B NM (i), B VM The value of (i) tends to stabilize. When the variance σ reaches its minimum value, ΔB can be considered to be at this point. Z This refers to the actual axial magnetic interference. Assume there are three measuring points: 1, 2, and 3. The original measurement data are represented by 1A, 2A, and 3A. The first change is ΔB. Z The values ​​of ΔBZ are chosen such that the measured data are 1B, 2B, and 3B; the values ​​of ΔBZ are chosen in the second change such that the measured data are 1C, 2C, and 3C; the values ​​of ΔBZ are chosen in the third change such that the measured data are 1C, 2C, and 3C; Z The values ​​of ΔB are chosen such that the measured data are 1D, 2D, and 3D. If the second change ΔB Z When ΔB takes the value of σ, the variance σ is at its minimum, meaning ΔB is at its minimum value. Z The second value is closer to the actual axial magnetic interference intensity.

[0134] Calculate the variance σ of the vertical and horizontal components of the magnetic field measured by the magnetic field measuring instrument at N measurement points and the local vertical and horizontal components of the first magnetic field strength according to the aforementioned formula 22:

[0135] According to the extreme value solution method, partial differential calculation of formula 22 yields:

[0136]

[0137] The stochastic gradient descent method can be used, taking the azimuth angle AZIcal after axial direction correction at each measurement point as the initial value, and solving Equation 23 above. When ΔB ZIf convergence occurs, or the number of iterations reaches the preset upper limit, then calculate ΔB at this point. Z This is the axial magnetic interference intensity value at the location closest to the Earth's magnetic field. For example, it is preset when ΔB Z The solution is terminated when the transformation value is less than 0.001 or the number of iterations reaches 1000, and the true axial magnetic disturbance ΔB is finally obtained. Z .

[0138] In one embodiment, in step S15 above, the final corrected azimuth angle of each measurement point is calculated based on the axial magnetic interference value at the location closest to the Earth's magnetic field. This can be achieved, for example, in the following manner:

[0139] Based on the axial magnetic interference value of the measurement point closest to the geomagnetic field, the difference between the fluxgate reading and the axial interference value along the drill string axis at each measurement point is calculated to obtain the corrected fluxgate reading in the axial direction at each measurement point.

[0140] Substitute the axial fluxgate readings and the radial fluxgate readings of each measurement point into the above azimuth calculation formula (1) to calculate the final corrected azimuth of each measurement point.

[0141] The above radially corrected fluxgate readings are referenced. Figure 2 The figure shows the fluxgate readings in the X and Y directions after radial correction in the measurement coordinate system. The axial fluxgate readings are the axial fluxgate readings after improved indirect multi-point correction. Based on the corrected fluxgate readings in these three directions and the azimuth calculation formula, the final corrected azimuth angle of each measurement point can be calculated.

[0142] Reference Figure 7 As shown in the figure, the experiment proves that the azimuth angle obtained by the multi-point indirect correction method is closer to the true azimuth angle than the azimuth angle obtained by the single-point indirect correction method.

[0143] The well inclination angle measured by a magnetic drilling rig in a certain location was 16.24°, and the actual azimuth angle was 56.93°. The correction results according to the method provided in the embodiment of the present invention are shown in Table 1 below. The error between the actual measured azimuth angle of the target point and the electrical measurement value is within 0.37, and the error of the other points is within 0.4.

[0144] Table 1

[0145]

[0146] The magnetic azimuth correction method provided in this invention can be implemented using computer software. Running this software, simulations and numerical analyses were conducted in the laboratory under different well inclination angles, azimuth angles, and magnetic interference conditions. An azimuth error correction reference diagram was plotted. The results showed that, under a fixed axial magnetic interference, the azimuth correction deviation is affected by both the well inclination angle and the actual azimuth angle. The correction required the most iterations and had the worst effect when the well inclination angle was 90±5°, the azimuth angle was 90±5°, or the azimuth angle was 270±5°, resulting in a maximum correction deviation greater than 10°, exceeding the instrument's azimuth measurement error range of less than 1.5°. Therefore, this software is helpful for reasonable well location deployment, wellbore trajectory design, and judging mixed errors in measurement values ​​under high-temperature conditions, exhibiting good field versatility and practicality.

[0147] Based on the same inventive concept, this embodiment of the invention also provides a magnetic azimuth angle correction device. Since the principle of solving the problem by these devices is similar to the aforementioned magnetic azimuth angle correction method, the implementation of this device can refer to the implementation of the aforementioned method, and the repeated parts will not be described again.

[0148] This invention provides a magnetic azimuth correction device, referring to... Figure 8 As shown, it includes:

[0149] The acquisition module 81 is used to acquire data from a set of measurement points measured by the magnetic drilling instrument; the data for each measurement point includes fluxgate readings in three directions in the instrument's measurement coordinate system;

[0150] Radial correction module 82 is used to correct the fluxgate reading of each measurement point along the radial direction of the drill string in the instrument measurement coordinate system for each measurement point.

[0151] The axial correction module 83 is used to correct the fluxgate reading of each measurement point after radial correction along the drill string axis in the instrument's measurement coordinate system, and calculate the azimuth angle based on the fluxgate reading of each measurement point after axial correction. Based on the azimuth angle calculated from the fluxgate readings of each measurement point in the set of measurement points after axial correction, the axial magnetic interference intensity value at the point closest to the Earth's magnetic field is calculated using the improved indirect multi-measurement point correction principle. Based on the axial magnetic interference value of the measurement point closest to the Earth's magnetic field, the final corrected azimuth angle of each measurement point is calculated.

[0152] This invention provides a computing device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the magnetic azimuth correction method as described above.

[0153] This invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the magnetic azimuth correction method as described above.

[0154] This invention provides a computer program product, characterized in that the computer program product includes a computer program, which, when executed by a processor, implements the magnetic azimuth correction method as described above.

[0155] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0156] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0157] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0158] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0159] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for magnetic azimuth correction, characterized in that, include: Obtain data from a set of measurement points measured by the magnetic measurement while drilling instrument; the data for each measurement point includes fluxgate readings in three directions in the instrument's measurement coordinate system; For each measurement point, the fluxgate reading of the measurement point along the radial direction of the drill string in the instrument's measurement coordinate system is corrected. For each measurement point after radial correction, the fluxgate reading of the measurement point along the drill string axis in the instrument measurement coordinate system is corrected, and the azimuth angle is calculated based on the fluxgate reading of each measurement point after axial correction. Based on the azimuth angle calculated from the fluxgate readings of each measurement point after axial direction correction, the axial magnetic interference intensity value at the point closest to the Earth's magnetic field is calculated using the improved indirect multi-measurement point correction axial magnetic interference principle. Based on the axial magnetic interference value of the measurement point closest to the geomagnetic field, the final corrected azimuth angle of each measurement point is calculated.

2. The method as described in claim 1, characterized in that, The fluxgate readings of the measurement points along the radial direction of the drill string in the instrument's measurement coordinate system are corrected, including: The magnetic interference of the magnetic hotspots causing radial interference on the magnetic measurement while drilling instrument, and the radially corrected fluxgate reading are calculated using the following formula: (B X1 -M X ) 2 +(B Y1 -M Y ) 2 =(B X2 -M X ) 2 +(B Y2 -M Y ) 2 =…=(B Xn -M X ) 2 +(B Yn -M Y ) 2 ; B XC =B X -M X ; B YC =B Y -M Y ; In the above formula, n represents the nth measurement point, B Xn B Yn B is the fluxgate reading at the nth measurement point along the radial direction of the drill string; XC and B YC This is the fluxgate reading after radial correction.

3. The method as described in claim 1, characterized in that, The fluxgate readings of the measurement points along the drill string axis in the instrument's measurement coordinate system are corrected, and the azimuth angle is calculated based on the axially corrected fluxgate readings of each measurement point, including: For each measurement point, the axial magnetic flux density is calculated using the local magnetic field strength and magnetic inclination, and the corrected first axial magnetic flux density component is obtained in reverse. The first corrected azimuth angle AZI_Short is solved using the first axial magnetic induction intensity component; The error E between the magnetic field strength calculated by the magnetic field measurement while drilling instrument and the Earth's magnetic field strength, and the axial fluxgate value B. ZM The quadratic relationship between them is used to find the minimum value of E by using the extreme value solution method. The axial fluxgate reading at the minimum value of E is then determined as the corrected second axial magnetic induction intensity component. Substitute the second axial magnetic flux density component into the azimuth calculation formula to obtain the second corrected azimuth angle AZI_indirect; The first corrected azimuth angle and the second corrected azimuth angle are weighted and calculated to obtain the azimuth angle AZI after axial direction correction. cal .

4. The method as described in claim 3, characterized in that, The first axial magnetic flux density component is calculated using the following formula: B V =B t cosDIP; B N =B t sinDIP; B zc =B t cosDIPcosAZIcosINC+B t cosDIPcosINC In the above formula, B zc B is the first axial magnetic induction component; N B represents the horizontal component of the local geomagnetic field, in μT. V B represents the vertical component of the local geomagnetic field, in μT; DIP represents the magnetic inclination, in °; t B is the magnetic flux density of the Earth's magnetic field, measured in μT. ZC 1. axial magnetic flux density component, unit μT; AZI is the corrected azimuth angle; The formula for calculating the first corrected azimuth angle AZI_Short is: HSG is the tool face angle; INC is the well inclination angle.

5. The method as described in claim 4, characterized in that, The formula for calculating the azimuth angle is:

6. The method as described in claim 3, characterized in that, The first corrected azimuth angle and the second corrected azimuth angle are weighted and calculated to obtain the azimuth angle AZI after axial direction correction. cal ,include: Calculate AZI using the following formula cal :

7. The method as described in claim 3, characterized in that, Based on the azimuth angle calculated from the fluxgate readings of each measurement point after axial direction correction, and using the improved indirect multi-point correction principle for axial magnetic interference, the axial magnetic interference intensity value closest to the geomagnetic field measurement point is calculated, including: Solve for the vertical and horizontal components of the magnetic field measured by the magnetic field measuring instrument at N measurement points, and the variance σ of the local geomagnetic field strength in the vertical and horizontal directions: According to the extreme value solution method, the above equation is calculated by partial differential equation to obtain: The azimuth angle AZI is calculated by using the stochastic gradient descent method to obtain the fluxgate readings of each measurement point after axial direction correction. cal Using ΔB as the initial value, we solve the above equation. Z If convergence occurs, or the number of iterations reaches the preset upper limit, then calculate ΔB at this point. Z , which is the axial magnetic interference intensity value at the location closest to the Earth's magnetic field.

8. The method as described in claim 7, characterized in that, Based on the axial magnetic interference value at the location closest to the Earth's magnetic field, the final corrected azimuth angle for each measurement point is calculated, including: Based on the axial magnetic interference value of the measurement point closest to the geomagnetic field, the difference between the fluxgate reading along the axial direction of the drill string and the axial interference value is calculated for each measurement point, and the corrected fluxgate reading in the axial direction is obtained for each measurement point. Substitute the axial fluxgate readings and the radial fluxgate readings of each measurement point into the azimuth calculation formula to calculate the final corrected azimuth of each measurement point.

9. A device for magnetic azimuth correction, characterized in that, include: The acquisition module is used to obtain data from a set of measurement points measured by the magnetic drilling instrument; the data for each measurement point includes fluxgate readings in three directions in the instrument's measurement coordinate system; The radial correction module is used to correct the fluxgate reading of each measurement point along the radial direction of the drill string in the instrument's measurement coordinate system for each measurement point. The axial correction module is used to correct the fluxgate reading of each measurement point along the drill string axis in the instrument's measurement coordinate system after radial correction, and calculate the azimuth angle based on the fluxgate reading after axial correction for each measurement point. Based on the azimuth angle calculated from the fluxgate readings after axial correction for each measurement point in the set of measurement points, the axial magnetic interference intensity value at the point closest to the Earth's magnetic field is calculated using the improved indirect multi-measurement point correction principle. Based on the axial magnetic interference value at the measurement point closest to the Earth's magnetic field, the final corrected azimuth angle of each measurement point is calculated.

10. A computing device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the magnetic azimuth correction method as described in any one of claims 1-8.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the magnetic azimuth correction method as described in any one of claims 1-8.

12. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the magnetic azimuth correction method as described in any one of claims 1-8.

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