Method and device for decoupling electromagnetic wave components of a while-drilling electromagnetic wave logging instrument

Abstract

The application discloses a method and device for decoupling electromagnetic wave components of a while-drilling electromagnetic wave logging instrument. The method comprises the following steps: acquiring a short-section angle difference between a transmitting section and a receiving section and a butt joint angle difference between a transmitting coil and each receiving coil; for each receiving coil, fitting a fitting value of a waveform coefficient corresponding to a component function in a waveform function of an acquired electromagnetic wave signal; obtaining a rotation matrix according to the short-section angle difference and the butt joint angle difference between the transmitting coil and the receiving coil; constructing a plurality of waveform coefficient expression formulas according to a deflection angle corresponding to the receiving coil, the rotation matrix, the fitting value of the plurality of waveform coefficients and a deflection angle of the transmitting coil; and obtaining electromagnetic field components in a transmitting section coordinate system according to the waveform coefficient expression formulas corresponding to the plurality of receiving coils. In this way, the electromagnetic wave components can be decoupled to the transmitting section coordinate system simply and efficiently when the transmitting section coordinate system and the receiving section coordinate system are in any relative inclination angle state.

Description

Technical Field

[0001] This application relates to the field of well logging technology, specifically to a method, apparatus, computing device, computer storage medium, and computer program product for decoupling electromagnetic wave components of a drilling electromagnetic wave logging tool. Background Technology

[0002] In recent years, to more accurately acquire and evaluate formation electrical parameters, drilling electromagnetic wave (EMWW) logging requires more comprehensive electromagnetic field component information. Early EMWW resistivity logging only required a specific electromagnetic field component to measure conventional resistivity; next-generation drilling azimuth EMWW resistivity logging not only needs a specific electromagnetic field component for conventional resistivity measurement but also requires cross-electromagnetic field components to provide formation azimuth information; the latest drilling ultra-deep EMWW and drilling forward EMWW logging require extracting all electromagnetic field components to meet the needs of peri-wellbore three-dimensional inversion imaging. Therefore, accurately acquiring all electromagnetic field components has become crucial for obtaining formation information in the field of drilling EMWW logging.

[0003] Deep-drilling electromagnetic (EMW) logging tools and forward-looking EMWD tools often employ separate transmitter and receiver sections to provide a longer source-to-source distance and thus a wider detection range. However, in actual instrument string assembly, misalignment between the transmitter and receiver sections is common. In highly deviated and horizontal wells, the wellbore trajectory is complex and curved, especially in the build-up section. Due to the large source-to-source distance, the inclination and azimuth angles of the transmitter and receiver sections differ significantly, leading to a misalignment between their coordinate systems. This greatly increases the difficulty of decoupling the coupled measurement signals into independent components. Summary of the Invention

[0004] In view of the above problems, this application is made in order to provide a method, apparatus, computing device, computer storage medium and computer program product for decoupling electromagnetic wave components of a logging-while-drilling electromagnetic wave tool that overcomes or at least partially solves the above problems.

[0005] According to one aspect of this application, a method for decoupling electromagnetic wave components in a logging-while-drilling (LWD) electromagnetic wave tool is provided. The LWD electromagnetic wave tool includes a transmitting section and a receiving section. The transmitting section is equipped with a transmitting coil for transmitting electromagnetic wave signals, and the receiving section is equipped with multiple receiving coils for acquiring electromagnetic wave signals. The method includes:

[0006] Obtain the short section angle difference between the transmitting section and the receiving section, and the docking angle difference between the transmitting coil and each receiving coil;

[0007] For each receiving coil, fit the waveform coefficients of multiple component functions in the waveform function of the electromagnetic wave signal it collects.

[0008] The rotation matrix is ​​obtained based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil;

[0009] Based on the offset angle, rotation matrix, fitted values ​​of multiple waveform coefficients, and offset angle of the transmitting coil, multiple waveform coefficient expressions are constructed.

[0010] The electromagnetic field components in the transmitter coordinate system are obtained by solving the multiple waveform coefficient expressions corresponding to the multiple receiving coils.

[0011] Optionally, obtaining the electromagnetic field components in the transmitter coordinate system based on the multiple waveform coefficient expressions corresponding to the multiple receiving coils further includes:

[0012] By combining the expressions for multiple waveform coefficients corresponding to the multiple receiving coils to form an overdetermined system of equations, and solving the overdetermined system of equations, the electromagnetic field components in the transmitter coordinate system are obtained.

[0013] Optionally, the step of obtaining the electromagnetic field components in the transmitter coordinate system based on the waveform coefficient expressions corresponding to the plurality of receiving coils further includes:

[0014] Based on the source distance of each receiving coil, distance correction processing is performed on each waveform coefficient expression corresponding to the target receiving coil to obtain each equivalent waveform coefficient expression; wherein, the target receiving coil includes the receiving coil with the largest source distance and the receiving coil with the smallest source distance;

[0015] By combining the equivalent waveform coefficient expressions corresponding to the target receiving coil and the waveform coefficient expressions corresponding to other receiving coils besides the target receiving coil, the electromagnetic field components can be obtained.

[0016] Optionally, the number of receiving coils is three, and the distance correction processing of the waveform coefficient expressions corresponding to the target receiving coil based on the source distance of each receiving coil further includes:

[0017] Based on the minimum source distance and the source distances of the other receiving coils, the waveform coefficient expressions corresponding to the receiving coil with the minimum source distance are corrected to obtain the first corrected waveform coefficient expressions.

[0018] Based on the maximum source distance and the source distances of the other receiving coils, the waveform coefficient expressions corresponding to the receiving coil with the largest source distance are corrected to obtain the second corrected waveform coefficient expressions.

[0019] Based on the first corrected waveform coefficient expressions and the second corrected waveform coefficient expressions, the equivalent waveform coefficient expressions are obtained by combining them.

[0020] Optionally, the step of combining the first corrected waveform coefficient expressions and the second corrected waveform coefficient expressions to obtain the equivalent waveform coefficient expressions further includes:

[0021] For each component function in the waveform function, the first and second corrected waveform coefficient expressions corresponding to the component function are subjected to different linear combination processes to obtain the equivalent waveform coefficient expressions.

[0022] Optionally, the step of performing different linear combination processes on the first and second corrected waveform coefficient expressions corresponding to the component function to obtain the equivalent waveform coefficient expressions further includes:

[0023] The equivalent waveform coefficient expression is determined based on the sum of the first and second corrected waveform coefficient expressions corresponding to the component function, and the subtraction of the first and second corrected waveform coefficient expressions corresponding to the component function.

[0024] Optionally, the step of correcting the waveform coefficient expressions corresponding to the receiving coil with the smallest source distance based on the source distances of the other receiving coils to obtain the first corrected waveform coefficient expressions further includes:

[0025] The first correction coefficient is calculated based on the minimum source distance and the source distance of the other receiving coils. The first correction coefficient is then multiplied by the waveform coefficient expressions corresponding to the receiving coil with the smallest source distance to obtain the waveform coefficient expressions after the first correction.

[0026] The step of correcting the waveform coefficient expressions corresponding to the receiving coil with the largest source distance based on the source distance of the largest source distance and the source distances of the other receiving coils, to obtain the second corrected waveform coefficient expressions, further includes:

[0027] The second correction coefficient is calculated based on the maximum source distance and the source distance of the other receiving coils. The second correction coefficient is then multiplied by the waveform coefficient expressions corresponding to the receiving coil with the largest source distance to obtain the waveform coefficient expressions after the second correction.

[0028] Optionally, the short-section angle difference includes: the well inclination angle difference and the azimuth angle difference between the transmitting section and the receiving section.

[0029] Optionally, the step of constructing multiple waveform coefficient expressions based on the offset angle corresponding to the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil further includes:

[0030] The offset angle corresponding to the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil are substituted into multiple initial waveform coefficient expressions to obtain the multiple waveform coefficient expressions; wherein, the initial waveform coefficient expressions are used to characterize the coupling relationship between electromagnetic field components, elements in the rotation matrix, the offset angle corresponding to the transmitting coil, the offset angle corresponding to the receiving coil, and waveform coefficients.

[0031] Optionally, the waveform function corresponding to the electromagnetic wave signal includes multiple component functions, which include multiple different trigonometric functions, including 0th-order, 1st-order and 2nd-order trigonometric functions.

[0032] Optionally, calculating the first correction coefficient based on the minimum source distance and the source distances of the other receiving coils, and calculating the second correction coefficient based on the maximum source distance and the source distances of the other receiving coils, further includes:

[0033] A first correction coefficient is calculated based on the square of the minimum source distance and the square of the source distances of the other receiving coils; a second correction coefficient is calculated based on the square of the maximum source distance and the square of the source distances of the other receiving coils.

[0034] Alternatively, a first correction coefficient can be calculated based on the cube of the minimum source distance and the cube of the source distances of the other receiving coils; a second correction coefficient can be calculated based on the cube of the maximum source distance and the cube of the source distances of the other receiving coils.

[0035] According to another aspect of this application, an electromagnetic wave component decoupling device for a logging-while-drilling (LWD) electromagnetic wave tool is provided. The LWD electromagnetic wave tool includes a transmitting section and a receiving section. The transmitting section is equipped with a transmitting coil for transmitting electromagnetic wave signals, and the receiving section is equipped with multiple receiving coils for acquiring electromagnetic wave signals. The device includes:

[0036] The acquisition module is adapted to acquire the short section angle difference between the transmitting section and the receiving section, as well as the docking angle difference between the transmitting coil and each receiving coil;

[0037] The fitting module is suitable for fitting the waveform coefficients corresponding to multiple component functions in the waveform function of the electromagnetic wave signal acquired by each receiving coil.

[0038] The solution module is adapted to obtain the rotation matrix based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil; construct multiple waveform coefficient expressions based on the offset angle corresponding to the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil; and solve for the electromagnetic field components in the transmitting section coordinate system based on the multiple waveform coefficient expressions corresponding to the multiple receiving coils.

[0039] Alternatively, the solver module is further adapted to:

[0040] By combining the expressions for multiple waveform coefficients corresponding to the multiple receiving coils to form an overdetermined system of equations, and solving the overdetermined system of equations, the electromagnetic field components in the transmitter coordinate system are obtained.

[0041] Alternatively, the solver module is further adapted to:

[0042] Based on the source distance of each receiving coil, distance correction processing is performed on the waveform coefficient expressions corresponding to the target receiving coil to obtain the equivalent waveform coefficient expressions; wherein, the target receiving coil includes the receiving coil with the largest source distance and the receiving coil with the smallest source distance; by combining the equivalent waveform coefficient expressions corresponding to the target receiving coil and the waveform coefficient expressions corresponding to other receiving coils besides the target receiving coil, the electromagnetic field components are solved.

[0043] Optionally, the number of receiving coils is three, and the solving module is further adapted to:

[0044] Based on the minimum source distance and the source distances of the other receiving coils, the waveform coefficient expressions corresponding to the receiving coil with the minimum source distance are corrected to obtain the first corrected waveform coefficient expressions.

[0045] Based on the maximum source distance and the source distances of the other receiving coils, the waveform coefficient expressions corresponding to the receiving coil with the largest source distance are corrected to obtain the second corrected waveform coefficient expressions.

[0046] Based on the first corrected waveform coefficient expressions and the second corrected waveform coefficient expressions, the equivalent waveform coefficient expressions are obtained by combining them.

[0047] Alternatively, the solver module is further adapted to:

[0048] For each component function in the waveform function, the first and second corrected waveform coefficient expressions corresponding to the component function are subjected to different linear combination processes to obtain the equivalent waveform coefficient expressions.

[0049] Alternatively, the solver module is further adapted to:

[0050] The equivalent waveform coefficient expression is determined based on the sum of the first and second corrected waveform coefficient expressions corresponding to the component function, and the subtraction of the first and second corrected waveform coefficient expressions corresponding to the component function.

[0051] Alternatively, the solver module is further adapted to:

[0052] The first correction coefficient is calculated based on the minimum source distance and the source distance of the other receiving coils. The first correction coefficient is then multiplied by the waveform coefficient expressions corresponding to the receiving coil with the smallest source distance to obtain the waveform coefficient expressions after the first correction.

[0053] The second correction coefficient is calculated based on the maximum source distance and the source distance of the other receiving coils. The second correction coefficient is then multiplied by the waveform coefficient expressions corresponding to the receiving coil with the largest source distance to obtain the waveform coefficient expressions after the second correction.

[0054] Optionally, the short-section angle difference includes: the well inclination angle difference and the azimuth angle difference between the transmitting section and the receiving section.

[0055] Alternatively, the solver module is further adapted to:

[0056] The offset angle corresponding to the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil are substituted into multiple initial waveform coefficient expressions to obtain the multiple waveform coefficient expressions. The initial waveform coefficient expressions are used to characterize the coupling relationship between electromagnetic field components, elements in the rotation matrix, the offset angle corresponding to the transmitting coil, the offset angle corresponding to the receiving coil, and waveform coefficients.

[0057] Optionally, the waveform function corresponding to the electromagnetic wave signal includes multiple component functions, which include multiple different trigonometric functions, including 0th-order, 1st-order and 2nd-order trigonometric functions.

[0058] Alternatively, the solver module is further adapted to:

[0059] A first correction coefficient is calculated based on the square of the minimum source distance and the square of the source distances of the other receiving coils; a second correction coefficient is calculated based on the square of the maximum source distance and the square of the source distances of the other receiving coils.

[0060] Alternatively, a first correction coefficient can be calculated based on the cube of the minimum source distance and the cube of the source distances of the other receiving coils; a second correction coefficient can be calculated based on the cube of the maximum source distance and the cube of the source distances of the other receiving coils.

[0061] According to another aspect of this application, a computing device is provided, comprising: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus;

[0062] The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the above-described electromagnetic wave component decoupling method for drilling electromagnetic wave logging tools.

[0063] According to another aspect of this application, a computer storage medium is provided, wherein at least one executable instruction is stored therein, the executable instruction causing a processor to perform an operation corresponding to the above-described method for decoupling electromagnetic components in a logging-while-drilling (LWD) electromagnetic wave tool.

[0064] According to another aspect of this application, a computer program product is provided, including at least one executable instruction that causes a processor to perform operations corresponding to the above-described electromagnetic component decoupling method for logging-while-drilling electromagnetic wave tools.

[0065] According to the embodiments of this application, the electromagnetic wave component decoupling method, apparatus, computing device, computer storage medium, and computer program product for a logging-while-drilling (LWD) electromagnetic wave tool include a transmitting section and a receiving section. The transmitting section is equipped with a transmitting coil for transmitting electromagnetic wave signals, and the receiving section is equipped with multiple receiving coils for acquiring electromagnetic wave signals. The method acquires the short-section angle difference between the transmitting and receiving sections and the docking angle difference between the transmitting coil and each receiving coil. For each receiving coil, the method fits the waveform coefficients corresponding to multiple component functions in the waveform function of the acquired electromagnetic wave signal. Based on the short-section angle difference and the docking angle difference between the transmitting coil and the receiving coil, a rotation matrix is ​​obtained. Based on the offset angle corresponding to the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil, multiple waveform coefficient expressions are constructed. Based on the multiple waveform coefficient expressions corresponding to the multiple receiving coils, the electromagnetic field components in the transmitting section coordinate system are solved. By using the above method, based on the single-inclination coil transmitting and multi-inclination coil receiving coil system of the logging-while-drilling electromagnetic wave tool, the electromagnetic wave components can be decoupled to the transmitting coordinate system when the transmitting coordinate system and the receiving coordinate system are at any relative inclination angle, which can reduce the difficulty of decoupling the electromagnetic field components in the transmitting coordinate system.

[0066] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0067] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0068] Figure 1 A flowchart of an embodiment of the electromagnetic wave component decoupling method for logging-while-drilling electromagnetic wave tools provided in this application is shown;

[0069] Figure 2 A flowchart of a method for decoupling electromagnetic wave components in a logging-while-drilling (LWD) electromagnetic wave tool, according to another embodiment of this application, is shown.

[0070] Figure 3 A schematic diagram of the structure of a launch section provided in an embodiment of this application is shown;

[0071] Figure 4 A schematic diagram of the structure of a receiving section provided in an embodiment of this application is shown;

[0072] Figure 5 This diagram shows the positions of the launch and receiving sections under the 3D wellbore trajectory.

[0073] Figure 6 A flowchart of a method for decoupling electromagnetic wave components in a logging-while-drilling (LWD) electromagnetic wave tool, according to another embodiment of this application, is shown.

[0074] Figure 7 Magnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result;

[0075] Figure 8 Magnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result;

[0076] Figure 9 Magnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result;

[0077] Figure 10 Magnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result;

[0078] Figure 11 Magnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result;

[0079] Figure 12 Magnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result;

[0080] Figure 13 Electromagnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result;

[0081] Figure 14 Electromagnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result;

[0082] Figure 15 Electromagnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result;

[0083] Figure 16 Electromagnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result;

[0084] Figure 17 Electromagnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result;

[0085] Figure 18 Electromagnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result;

[0086] Figure 19 This paper shows a functional structure diagram of the electromagnetic wave component decoupling device for the logging-while-drilling electromagnetic wave tool provided in an embodiment of this application.

[0087] Figure 20 A schematic diagram of the structure of a computing device provided in an embodiment of this application is shown. Detailed Implementation

[0088] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application 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 application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0089] First, the electromagnetic field components involved in one or more embodiments of this application will be explained.

[0090] Taking the Hxy component as an example, traditionally, the Hxy component refers to the electromagnetic field component emitted in the x-direction and received in the y-direction, where x and y are in the same coordinate system. In the electromagnetic wave logging tool involved in this application, because the transmitting and receiving sections are separate and the source-to-source distance is long, the coordinate systems of the transmitting and receiving sections do not coincide when the wellbore trajectory is curved. When the electromagnetic wave logging tool rotates one revolution, the waveform measured by the receiving section couples all nine components in the receiving section coordinate system. By decoupling these components, the electromagnetic field components in the receiving section coordinate system, including HxyR, can be obtained. For any coordinate system, as long as the relative tilt, azimuth, and rotation angle (i.e., any relative tilt angle) between this coordinate system and the receiving section coordinate system are known, the components can be transformed to this coordinate system by coordinate rotation based on the relative direction; that is, HxyR is transformed into Hxya. In this application, it is chosen to decouple these components to the transmitting section coordinate system; that is, HxyR is transformed into HxyT.

[0091] The above decoupling process considers the rotation from the receiver coordinate system to the transmitter coordinate system, which is a reverse process. The embodiments of this application actually adopt a forward process, that is, the relative directional relationship between the transmitter and receiver is considered first, and HxyT is used instead of HxyR. The waveform measured by the instrument rotating one revolution couples all 9 components in the transmitter coordinate system, so it can be directly decoupled to the transmitter coordinate system during decoupling.

[0092] Figure 1 This invention illustrates a flowchart of an electromagnetic wave component decoupling method for a logging-while-drilling (LWD) electromagnetic wave tool according to an embodiment of this application. The LWD electromagnetic wave tool includes a transmitting section and a receiving section. The transmitting section is equipped with a transmitting coil for transmitting electromagnetic wave signals, and the receiving section is equipped with multiple receiving coils for acquiring electromagnetic wave signals. Figure 1 As shown, the method includes the following steps:

[0093] Step S110: Obtain the short section angle difference between the transmitting section and the receiving section, as well as the docking angle difference between the transmitting coil and each receiving coil.

[0094] The short-section angle difference between the transmitting and receiving sections includes the inclination angle difference and the azimuth angle difference. Since the transmitting and receiving sections are located at different positions on the wellbore trajectory, there are differences in their inclination and azimuth angles. The inclination and azimuth angles of the transmitting and receiving sections are obtained separately. The difference in the inclination angles of the transmitting and receiving sections is calculated to obtain the inclination angle difference, and the difference in the azimuth angles of the transmitting and receiving sections is calculated to obtain the azimuth angle difference. The docking angle difference between the transmitting and receiving coils specifically refers to the circumferential angle difference between the receiving and transmitting coils.

[0095] Step S120: For each receiving coil, fit the waveform coefficients corresponding to multiple component functions in the waveform function of the electromagnetic wave signal it has acquired.

[0096] Multiple receiving coils are wound around the receiving section, and the receiving coils are spaced at a certain angle around each other in the circumferential direction. During the rotation measurement process of the electromagnetic wave logging tool, electromagnetic wave signals carrying formation telecommunication characteristics are collected.

[0097] Electromagnetic wave signals can be represented by waveform functions. Waveform functions are used to characterize the relationship between a specified independent variable and the change of electromagnetic wave signals. A waveform function contains multiple basic component functions, and the coefficients of the component functions are multiple waveform coefficients to be determined. By data fitting, the fitted values ​​of the waveform coefficients corresponding to each component function in the waveform function are determined.

[0098] Step S130: Calculate the rotation matrix based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil.

[0099] The rotation matrix is ​​calculated by using the angular difference between the short sections and the docking angle difference between the receiving coil and the transmitting coil. The rotation matrix contains elements with multiple rows and columns.

[0100] Step S140: Construct multiple waveform coefficient expressions based on the offset angle, rotation matrix, fitted values ​​of multiple waveform coefficients, and offset angle of the transmitting coil corresponding to the receiving coil.

[0101] The offset angle corresponding to the receiving coil refers to the angle between the normal of the receiving coil and the axis of the receiving section, while the offset angle corresponding to the transmitting coil refers to the angle between the normal of the transmitting coil and the axis of the transmitting section.

[0102] Waveform coefficients are the coupling of electromagnetic field components. Specifically, each waveform coefficient is related to some elements in the rotation matrix, some electromagnetic field components, the offset angle corresponding to the receiving coil, and the offset angle corresponding to the transmitting coil. Therefore, only the electromagnetic field components are unknowns in the constructed waveform coefficient expression.

[0103] Step S150: Based on the multiple waveform coefficient expressions corresponding to multiple receiving coils, the electromagnetic field components in the transmitting section coordinate system are obtained.

[0104] Specifically, the electromagnetic field components are multiple components of the magnetic field tensor or multiple components of the electric field tensor. Both the multiple components of the magnetic field tensor and the multiple components of the electric field tensor can be decoupled and obtained according to the method of the embodiments of this application. Specifically, the electromagnetic field components are the electromagnetic field components in the transmitter coordinate system. The meaning of each electromagnetic field component is that the electromagnetic field measured by the coil system transmitting and receiving along any axis in the transmitter coordinate system is measured in the transmitter coordinate system. The transmitter coordinate system is a three-dimensional coordinate system; therefore, there are a total of 9 electromagnetic field components.

[0105] Assuming there are N receiving coils and M waveform coefficients, then for each receiving coil, M waveform coefficient expressions will be constructed, resulting in a total of N×M waveform coefficient expressions. Only the electromagnetic field components are unknown. Based on this, an overdetermined set of equations about the electromagnetic field components is formed according to the N×M waveform coefficient expressions. All nine electromagnetic field components in the transmitter coordinate system are obtained. The electromagnetic field components are all complex numbers, containing real and imaginary signals. By decoupling, the real and imaginary signals of each electromagnetic field component can be obtained.

[0106] In summary, the electromagnetic wave component decoupling method for the logging-while-drilling (LWD) electromagnetic wave tool provided in this embodiment obtains the short section angle difference between the transmitting and receiving sections and the docking angle difference between the transmitting coil and each receiving coil. For each receiving coil, the fitting values ​​of waveform coefficients corresponding to multiple component functions in the waveform function of the electromagnetic wave signal it acquires are fitted. A rotation matrix is ​​obtained based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil. Multiple waveform coefficient expressions are constructed based on the offset angle corresponding to the receiving coil, the rotation matrix, the fitting values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil. The electromagnetic field components in the transmitting section coordinate system are solved based on the multiple waveform coefficient expressions corresponding to the multiple receiving coils. Through this method, based on the single-tilt coil transmitting and multi-tilt coil receiving coil system of the LWD electromagnetic wave tool, the electromagnetic wave components can be decoupled to the transmitting section coordinate system when the transmitting section coordinate system and the receiving section coordinate system are at any relative tilt angle, thus reducing the difficulty of decoupling the electromagnetic field components in the transmitting section coordinate system.

[0107] Figure 2 The flowchart of another embodiment of the present application provides a method for decoupling electromagnetic wave components in a logging-while-drilling (LWD) electromagnetic wave tool. The LWD electromagnetic wave tool includes a transmitting section and a receiving section. A transmitting coil is wound on the transmitting section for transmitting electromagnetic wave signals, and three receiving coils are wound on the receiving section for acquiring electromagnetic wave signals. All nine electromagnetic field components are obtained by decoupling the electromagnetic wave signals acquired by each receiving coil. The method of the present application uses multiple waveform coefficient expressions to directly decouple the components, and is referred to as the direct decoupling method.

[0108] Figure 3 This illustration shows a schematic diagram of the transmitter section according to an embodiment of this application. The angle between the normal of the transmitter coil T and the axis of the transmitter section is [insert angle here]. xyz represents the launch node coordinate system. Indicates the coordinate system of the transmitting coil. z is the coordinate system of the transmitting coil T The angle between the direction and the z-direction of the launch node coordinate system. Indicates the direction of rotation; Figure 4This illustration shows a schematic diagram of a receiving section according to an embodiment of the present application. Receiving coils R1, R2, and R3 are wound around the receiving section, and the three receiving coils are spaced apart from each other at a certain angle in the circumferential direction. Indicates the receiving node coordinate system. This represents the coordinate system of the j-th (j=1,2,3) receiving coil, where the angle between the normal of the j-th receiving coil and the axis of the receiving section is... Specifically, in the coordinate system of the j-th receiving coil Orientation and receiving node coordinate system The angle between directions. In some instances, , , , All three receiving coils are arranged at 45° intervals around the circumference, with 120° intervals between them. Figure 5 This diagram illustrates the positions of the launcher and receiver sections in a 3D wellbore trajectory. The launcher and receiver sections are located at positions A and B in the wellbore trajectory, respectively. The inclination angle and azimuth angle of the launcher section are as follows: and The well inclination angle and azimuth angle of the receiving section are respectively and The axis of the transmitting coil is not along the axis of the transmitting section coordinate system, and the axes of the three receiving coils are not along the axis of the receiving section coordinate system, and they are not parallel to each other. According to the principle of electromagnetic reciprocity, the above coil system can also be equivalent to: three transmitting coils arranged in an array at a certain angle in the circumferential direction, transmitting electromagnetic wave signals in an inclined posture, and one inclined receiving coil receiving electromagnetic wave signals.

[0109] like Figure 2 As shown, the method includes the following steps:

[0110] Step S210: Obtain the short section angle difference between the transmitting section and the receiving section, as well as the docking angle difference between the transmitting coil and each receiving coil.

[0111] The short-section angle difference includes the wellbore inclination angle difference and azimuth angle difference between the transmitting and receiving sections. The wellbore inclination angle difference is obtained by subtracting the wellbore inclination angles of the transmitting and receiving sections, and the azimuth angle difference is obtained by subtracting the azimuth angles of the transmitting and receiving sections. The circumferential angle difference between the transmitting and receiving coils is the docking angle difference.

[0112] Step S220: According to the preset number of samplings, electromagnetic wave signals are collected during the rotation of the receiving coil. For each receiving coil, the fitting values ​​of the waveform coefficients corresponding to multiple component functions in the waveform function of the electromagnetic wave signal it collects are fitted.

[0113] During the rotation measurement process of the electromagnetic logging-while-drilling tool, the receiving coil can sample signals carrying the electrical characteristics of the formation by rotating once.

[0114] Specifically, the waveform function of the electromagnetic wave signal comprises multiple component functions, including several different trigonometric functions of order 0, 1, and 2. These waveform functions characterize the relationship between the sampling angle and the electromagnetic wave signal. Furthermore, using a data fitting method, the fitted values ​​of the waveform coefficients corresponding to the multiple component functions of the electromagnetic wave signal's waveform function are obtained based on the sampling angle.

[0115] The waveform function of the electromagnetic wave signal collected by the j-th receiving coil is shown in formula (1):

[0116] (1)

[0117] For the j-th receiving coil, The collected electromagnetic wave signal is composed of trigonometric functions. The waveform coefficient (also called the i-th waveform coefficient) represents the i-th component function (i=0, 1, 2, 3, 4) in the waveform function of the collected electromagnetic wave signal. This represents the waveform coefficients corresponding to the 0th order trigonometric functions. and This represents the waveform coefficients corresponding to two different first-order trigonometric functions. and This represents the waveform coefficients corresponding to two different second-order trigonometric functions. This represents the sampling angle of the j-th receiving coil during the nth sampling.

[0118] Based on the collected electromagnetic wave signals and sampling angles, the waveforms collected by each receiving coil are fitted using the least squares method or analytical method to obtain the fitted values ​​of each waveform coefficient. That is, the specific values ​​of the waveform coefficients corresponding to the above-mentioned 0th, 1st, and 2nd order trigonometric functions are obtained.

[0119] Step S230: Calculate the rotation matrix based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil.

[0120] In this embodiment, the rotation matrix specifically contains three rows and three columns of elements. The elements in the rotation matrix corresponding to the j-th receiving coil are calculated as follows:

[0121] (2)

[0122] In this equation, the left side represents the rotation matrix corresponding to the j-th receiving coil, and the right side shows the calculation method for each element in the rotation matrix. The first two numbers in the subscript of each element in the rotation matrix are the row number and column number, respectively. This indicates the difference in well inclination angle between the transmitting and receiving sections. This indicates the azimuth difference between the transmitting and receiving nodes. This represents the docking angle difference between the transmitting coil and the j-th receiving coil.

[0123] Step S240: Substitute the offset angle, rotation matrix, fitted values ​​of multiple waveform coefficients, and offset angle of the transmitting coil corresponding to the receiving coil into multiple initial waveform coefficient expressions to obtain multiple waveform coefficient expressions.

[0124] The initial waveform coefficient expression characterizes the coupling relationship between the electromagnetic field components, the elements in the rotation matrix, the offset angle corresponding to the transmitting coil, the offset angle corresponding to the receiving coil, and the waveform coefficients. The offset angle corresponding to the transmitting coil is the angle between the normal of the transmitting coil and the axis of the transmitting section, and the offset angle corresponding to the receiving coil is the angle between the normal of the receiving coil and the axis of the receiving section.

[0125] Taking the magnetic field component as an example, the expressions for the multiple initial waveform coefficients are as follows:

[0126] (3)

[0127] (4)

[0128] (5)

[0129] (6)

[0130] (7)

[0131] in, This represents the angle between the normal of the transmitting coil and the axis of the transmitting section, i.e., the offset angle corresponding to the transmitting coil; This represents the angle between the normal of the j-th receiving coil and the axis of the receiving section, i.e., the offset angle corresponding to the j-th receiving coil; , , , , , , , , These represent the magnetic field components in the transmitter coordinate system. The first letter in the subscript of the magnetic field component indicates the transmission direction, and the second letter indicates the receiving direction. To illustrate the meaning of magnetic field components, let's take an example. Specifically, this refers to the magnetic field measured by the coil system that emits along the x-axis and receives along the X-axis in the transmitter coordinate system. The meanings of other magnetic field components are deduced similarly and will not be elaborated here.

[0132] Step S250: Combine multiple waveform coefficient expressions corresponding to multiple receiving coils to form an overdetermined system of equations, solve the overdetermined system of equations, and obtain the electromagnetic field components in the transmitter coordinate system.

[0133] According to formulas (3)-(7), after substituting the elements of the rotation matrix, the offset angle corresponding to the transmitting coil, the offset angle corresponding to the receiving coil, and the fitted values ​​of multiple waveform coefficients into the corresponding initial waveform coefficient expressions, only each magnetic field component is an unknown. Since a receiving coil can form 5 waveform coefficient expressions, there are a total of 15 waveform coefficient expressions. By simultaneously solving these 15 waveform coefficient expressions, an overdetermined system of equations is formed for all 9 magnetic field components. Solving the overdetermined system of equations yields all 9 magnetic field components in the transmitting section coordinate system.

[0134] In one alternative approach, the solution process for each magnetic field component in the launch node coordinate system is as follows:

[0135] (8)

[0136] (9)

[0137] (10)

[0138] (11)

[0139] (12)

[0140] (13)

[0141] (14)

[0142] (15)

[0143] (16)

[0144] in, , , , , , , , , , , , , , These are different intermediate variables.

[0145] In one alternative approach, the intermediate variables are calculated as follows:

[0146] (17)

[0147] (18)

[0148] (19)

[0149] (20)

[0150] (twenty one)

[0151] (twenty two)

[0152] (twenty three)

[0153] (twenty four)

[0154] (25)

[0155] (26)

[0156] (27)

[0157] (28)

[0158] (29)

[0159] (30)

[0160] It should be noted that the initial waveform coefficient expression of the electric field component is similar to that of the magnetic field component, and is also constructed based on multi-order trigonometric functions. The decoupling process of the electric field component is similar to that of the magnetic field component, and will not be elaborated here.

[0161] In summary, according to the electromagnetic wave component decoupling method of the logging-while-drilling electromagnetic wave tool provided in this embodiment, the rotation matrix is ​​calculated by fitting the waveform coefficients of the electromagnetic wave signals collected by each receiving coil, considering the well inclination angle difference, azimuth angle difference, and docking angle difference between the transmitting and receiving sections, and the docking angle difference between the coils. Then, using the waveform coefficients, the offset angles of the transmitting and receiving coils, the coupling relationship between the rotation matrix and the electromagnetic field components, multiple waveform coefficient expressions are constructed. By combining the multiple waveform coefficient expressions corresponding to each receiving coil, the electromagnetic field components in the transmitting section coordinate system are obtained. In this way, the electromagnetic wave components can be decoupled to the transmitting section coordinate system when the transmitting and receiving section coordinate systems are at any relative tilt angle, which can reduce the difficulty of decoupling the electromagnetic field components in the transmitting section coordinate system.

[0162] Figure 6 This document illustrates a flowchart of an electromagnetic wave component decoupling method for a logging-while-drilling (LWD) electromagnetic wave tool according to another embodiment of this application. The method in this embodiment utilizes multiple waveform coefficient expressions for decoupling based on combined equivalence, and is referred to simply as the combined equivalent decoupling method. Figure 6 As shown, the method includes the following steps:

[0163] Step S610: Obtain the short section angle difference between the transmitting section and the receiving section, as well as the docking angle difference between the transmitting coil and each receiving coil.

[0164] Step S620: For each receiving coil, fit the waveform coefficients corresponding to multiple component functions in the waveform function of the electromagnetic wave signal it has acquired.

[0165] Step S630: Calculate the rotation matrix based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil.

[0166] Step S640: Based on the offset angle, rotation matrix, fitting values ​​of multiple waveform coefficients, and offset angle of the transmitting coil corresponding to the receiving coil, construct multiple waveform coefficient expressions.

[0167] The specific implementation methods of steps S610-S640 are consistent with the implementation methods of the corresponding steps in the foregoing embodiments, and will not be repeated here.

[0168] Step S650: Based on the source distance of each receiving coil, perform distance correction processing on the waveform coefficient expressions corresponding to the target receiving coil to obtain the equivalent waveform coefficient expressions; wherein, the target receiving coil includes the receiving coil with the largest source distance and the receiving coil with the smallest source distance.

[0169] The source distance of the receiving coil refers to the distance between the receiving coil and the transmitting coil. The distance between different receiving coils and transmitting coils is not consistent. For the receiving coil with the largest source distance and the receiving coil with the smallest source distance, the waveform coefficient expression is subjected to distance correction processing based on the electromagnetic wave attenuation characteristics according to multiple different source distances, resulting in multiple equivalent waveform coefficient expressions.

[0170] When there are three receiving coils, the distance correction processing for the waveform coefficient expressions corresponding to the target receiving coil based on the source distance of each receiving coil further includes: correcting the waveform coefficient expressions corresponding to the receiving coil with the smallest source distance based on the source distance of the smallest source distance and the source distance of other receiving coils to obtain each first corrected waveform coefficient expression; correcting the waveform coefficient expressions corresponding to the receiving coil with the largest source distance based on the source distance of the largest source distance and the source distance of other receiving coils to obtain each second corrected waveform coefficient expression; and combining the first corrected waveform coefficient expressions and the second corrected waveform coefficient expressions to obtain each equivalent waveform coefficient expression.

[0171] If the electromagnetic logging tool includes three receiving coils, then besides the receiving coils with the largest and smallest source distances, there is only one other receiving coil. The first corrected waveform coefficient expression is obtained by calculating the source distances of the smallest source distance and the other receiving coils, as well as the waveform coefficient expression corresponding to the receiving coil with the smallest source distance. The second corrected waveform coefficient expression is obtained by calculating the source distances of the largest source distance and the other receiving coils, as well as the waveform coefficient expression corresponding to the receiving coil with the largest source distance. The first and second corrected waveform coefficient expressions are combined to obtain a new waveform coefficient expression, thus yielding multiple equivalent waveform coefficient expressions.

[0172] In one alternative approach, the step of correcting the waveform coefficient expressions corresponding to the receiving coil with the smallest source distance based on the source distances of the smallest source distance and other receiving coils to obtain the first corrected waveform coefficient expressions further includes: calculating the first correction coefficient based on the source distances of the smallest source distance and other receiving coils, and multiplying the first correction coefficient by the waveform coefficient expressions corresponding to the receiving coil with the smallest source distance to obtain the first corrected waveform coefficient expressions, as shown in formula (31):

[0173] (31)

[0174] in, Let represent the expression for the i-th (i=0, 1, 2, 3, 4) first-corrected waveform coefficient. This represents the expression for the i-th waveform coefficient corresponding to the receiving coil with the smallest source-to-source distance (i.e., the expression for the waveform coefficient corresponding to the i-th component function in the waveform function). The expression for the i-th waveform coefficient represents the coupling relationship between the i-th waveform coefficient and the electromagnetic field component. Indicates the minimum source distance. This indicates the source distance of all receiving coils except for the receiving coil with the smallest source distance and the receiving coil with the largest source distance. This represents the first correction coefficient. That is, a parameter is calculated based on the minimum source distance and the source distances of other receiving coils. The elements on both sides of the equal sign of the i-th waveform coefficient expression corresponding to the receiving coil with the minimum source distance are multiplied by this parameter to obtain the i-th waveform coefficient expression after the first correction.

[0175] Accordingly, the step of correcting the waveform coefficient expressions corresponding to the receiving coil with the largest source distance based on the source distances of the largest source distance and other receiving coils, to obtain the second corrected waveform coefficient expressions, further includes: calculating the second correction coefficient based on the source distances of the largest source distance and other receiving coils, and multiplying the second correction coefficient by the waveform coefficient expressions corresponding to the receiving coil with the largest source distance to obtain the second corrected waveform coefficient expressions. The calculation method is shown in formula (32):

[0176] (32)

[0177] in, This represents the expression for the i-th waveform coefficient after second correction. This represents the expression for the i-th waveform coefficient corresponding to the receiving coil with the largest source distance (i.e., the expression for the waveform coefficient corresponding to the i-th component function in the waveform function). Indicates the maximum source distance. This indicates the source distance of all receiving coils except for the receiving coil with the smallest source distance and the receiving coil with the largest source distance. This represents the second correction coefficient. That is, a parameter is calculated based on the maximum source distance and the source distances of other receiving coils. The elements on both sides of the equal sign of the i-th waveform coefficient expression corresponding to the receiving coil with the largest source distance are multiplied by this parameter to obtain the i-th waveform coefficient expression after the second correction.

[0178] In one alternative approach, the steps of calculating the first correction coefficient and the second correction coefficient specifically include: calculating the first correction coefficient based on the square of the minimum source distance and the square of the source distance of the other receiving coils; and calculating the second correction coefficient based on the square of the maximum source distance and the square of the source distance of the other receiving coils, as shown in formulas (33) and (34) respectively.

[0179] (33)

[0180] (34)

[0181] In one alternative approach, the steps of calculating the first correction coefficient and the second correction coefficient specifically include: calculating the first correction coefficient based on the cube of the minimum source distance and the cube of the source distances of other receiving coils; and calculating the second correction coefficient based on the cube of the maximum source distance and the cube of the source distances of other receiving coils, as shown in formulas (35) and (36), respectively.

[0182] (35)

[0183] (36)

[0184] After calculating the first and second corrected waveform coefficient expressions, a linear combination of the waveform coefficient expressions is performed to finally obtain multiple equivalent waveform coefficient expressions.

[0185] Specifically, the step of combining the first and second corrected waveform coefficient expressions to obtain the equivalent waveform coefficient expressions further includes: for each component function in the waveform function, performing different linear combination processing on the corresponding first and second corrected waveform coefficient expressions to obtain the equivalent waveform coefficient expressions. That is, by combining the first and second corrected waveform coefficient expressions according to different linear combination methods, multiple equivalent waveform coefficient expressions are obtained, specifically including multiple first equivalent waveform coefficient expressions and multiple second equivalent waveform coefficient expressions.

[0186] In one optional approach, the equivalent waveform coefficient expression is determined by adding the first and second corrected waveform coefficient expressions corresponding to the component function, and by subtracting the first and second corrected waveform coefficient expressions corresponding to the component function. Optionally, the calculation methods are shown in formulas (37) and (38), respectively:

[0187] (37)

[0188] (38)

[0189] in, This represents the expression for the i-th first equivalent waveform coefficient. This represents the expression for the i-th second equivalent waveform coefficient. This represents the expression for the i-th waveform coefficient after the first correction. This represents the expression for the i-th waveform coefficient after the second correction.

[0190] It should be noted that the waveform function has waveform coefficients corresponding to multiple component functions. Correspondingly, there are multiple waveform coefficient expressions, first corrected waveform coefficient expressions, second corrected waveform coefficient expressions, first equivalent waveform coefficient expressions, and second equivalent waveform coefficient expressions. Specifically, for the waveform coefficient expression corresponding to the i-th waveform coefficient (i.e., the coefficient corresponding to the i-th component function) of the receiving coil with the smallest source distance, it is multiplied by the first correction coefficient to obtain the i-th first corrected waveform coefficient expression. For the waveform coefficient expression corresponding to the i-th waveform coefficient of the receiving coil with the largest source distance, it is multiplied by the second correction coefficient to obtain the i-th second corrected waveform coefficient expression. The average of the i-th first corrected waveform coefficient expression and the i-th second corrected waveform coefficient expression is obtained to obtain the i-th first equivalent waveform coefficient expression. The difference between the i-th first corrected waveform coefficient expression and the i-th second corrected waveform coefficient expression is divided by 2 to obtain the i-th second equivalent waveform coefficient expression.

[0191] Step S660: Combine the equivalent waveform coefficient expressions corresponding to the target receiving coil and the waveform coefficient expressions corresponding to other receiving coils besides the target receiving coil to solve for the electromagnetic field components.

[0192] In this embodiment, there are 3 receiving coils, and each receiving coil corresponds to 5 waveform coefficient expressions. The waveform coefficient expressions corresponding to the coil with the largest source distance and the coil with the smallest source distance are processed by distance correction to obtain 10 equivalent waveform coefficient expressions. By combining the 10 equivalent waveform coefficient expressions with the waveform coefficient expressions of the 5 waveform function coefficients corresponding to the other receiving coils, a total of 15 waveform coefficient expressions are obtained. All 9 electromagnetic field components are solved. Each waveform coefficient expression contains all or part of the unknown electromagnetic field components, and the waveform coefficient expressions are nonlinearly related to each other.

[0193] In existing technologies, the single-tilt transmit-multi-tilt receive mode can simplify the antenna system. However, since it is difficult to wind multiple coils with different tilt directions at the same point, multiple receiving coils are usually arranged in an array with a certain spacing. Simultaneously, to increase the detection range, the transmitting and receiving sections are usually separated, with other instrument strings combined in the middle, resulting in a longer source distance. Multiple receiving sections are used to receive signals at different source distances, enriching the detection information. However, the spacing between the multiple receiving coils on the receiving section can introduce errors in component decoupling. Existing technologies lack electromagnetic field component decoupling schemes that consider the differences in source distance between different receiving coils.

[0194] In summary, according to the drilling electromagnetic wave signal processing method provided in this embodiment, for each receiving coil, based on the electromagnetic wave signal it collects, a waveform coefficient expression for waveform coefficients and electromagnetic field components is constructed. The waveform coefficient expressions corresponding to the receiving coils with the smallest and largest source distances are distance-corrected. By combining the distance-corrected waveform coefficient expressions with other waveform coefficient expressions, the electromagnetic field component signal is decoupled and obtained. This alleviates the problem that the source distance difference between multiple receiving coils will cause errors in the decoupling of electromagnetic field components, and improves the accuracy of electromagnetic field component decoupling when the source distances of the receiving coils are inconsistent. At the same time, it can also decouple the electromagnetic wave components to the transmitting node coordinate system when the transmitting node coordinate system and the receiving node coordinate system are at any relative tilt angle, which can reduce the difficulty of decoupling the electromagnetic field components in the transmitting node coordinate system.

[0195] Figure 7 Magnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result, wherein, Represents model calculation The true imaginary part of the signal (i.e., the theoretical value). This indicates that the decoupling method obtained by using the direct decoupling method of the embodiments of this application is used. The imaginary part of the signal, due to and The error between them is small, and their curves overlap. Figure 8 Magnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result, wherein, Represents model calculation The true imaginary part of the signal (i.e., the theoretical value). This indicates that the decoupling method obtained by using the direct decoupling method of the embodiments of this application is used. The imaginary part of the signal, due to and The error between them is small, and their curves overlap. Figure 9 Magnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result, wherein, Represents model calculation The true imaginary part of the signal (i.e., the theoretical value). This indicates that the decoupling method obtained by using the direct decoupling method of the embodiments of this application is used. The imaginary part of the signal, due to and The error between them is small, and their curves overlap.

[0196] Figure 10 Magnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result, wherein, Represents model calculation The real part of the signal (i.e., the theoretical value). This indicates that the decoupling method obtained by using the direct decoupling method of the embodiments of this application is used. The real part of the signal, due to and The error between them is small, and their curves overlap. Figure 11 Magnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result, wherein, Represents model calculation The real part of the signal (i.e., the theoretical value). This indicates that the decoupling method obtained by using the direct decoupling method of the embodiments of this application is used. The real part of the signal, due to and The error between them is small, and their curves overlap. Figure 12 Magnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result, wherein, Represents model calculation The real part of the signal (i.e., the theoretical value). This indicates that the decoupling method obtained by using the direct decoupling method of the embodiments of this application is used. The real part of the signal, due to and The error between them is small, and their curves overlap.

[0197] Figure 13 Electromagnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result, wherein, Represents model calculation The true imaginary part of the signal (i.e., the theoretical value). This indicates that the decoupling obtained by using the combined equivalent decoupling method of the embodiments of this application is... The imaginary part of the signal, and The error between them is small, and their curves overlap. Figure 14 Electromagnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result, wherein, Represents model calculation The true imaginary part of the signal (i.e., the theoretical value). This indicates that the decoupling obtained by using the combined equivalent decoupling method of the embodiments of this application is... The imaginary part of the signal, and The error between them is small, and their curves overlap. Figure 15Electromagnetic field components in application examples A schematic diagram of the real imaginary part signal and the decoupling result, wherein, Represents model calculation The true imaginary part of the signal (i.e., the theoretical value). This indicates that the decoupling obtained by using the combined equivalent decoupling method of the embodiments of this application is... The imaginary part of the signal, and The error between them is small, and their curves overlap.

[0198] Figure 16 Electromagnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result, wherein, Represents model calculation The real part of the signal (i.e., the theoretical value). This indicates that the decoupling obtained by using the combined equivalent decoupling method of the embodiments of this application is... The real part of the signal, and The error between them is small, and their curves overlap. Figure 17 Electromagnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result, wherein, Represents model calculation The real part of the signal (i.e., the theoretical value). This indicates that the decoupling obtained by using the combined equivalent decoupling method of the embodiments of this application is... The real part of the signal, and The error between them is small, and their curves overlap. Figure 18 Electromagnetic field components in application examples A schematic diagram of the real real part of the signal and the decoupling result, wherein, Represents model calculation The real part of the signal (i.e., the theoretical value). This indicates that the decoupling obtained by using the combined equivalent decoupling method of the embodiments of this application is... The real part of the signal, and The error between them is small, and their curves overlap.

[0199] The comparison between the actual values ​​of the magnetic field components and the decoupling results shows that the real and imaginary signals of each magnetic field component obtained by decoupling using the method of the present application are close to the corresponding theoretical values, thus verifying the accuracy of the decoupling method of the present application.

[0200] Figure 19This diagram illustrates the functional structure of the electromagnetic wave component decoupling device for a logging-while-drilling (LWD) electromagnetic wave tool provided in an embodiment of this application. The LWD electromagnetic wave tool includes a transmitting section and a receiving section. The transmitting section is equipped with a transmitting coil for transmitting electromagnetic wave signals, and the receiving section is equipped with multiple receiving coils for acquiring electromagnetic wave signals. Figure 19 As shown, the device includes:

[0201] The acquisition module 1901 is adapted to acquire the short section angle difference between the transmitting section and the receiving section, as well as the docking angle difference between the transmitting coil and each receiving coil;

[0202] The fitting module 1902 is suitable for fitting the waveform coefficients corresponding to multiple component functions in the waveform function of the electromagnetic wave signal acquired by each receiving coil.

[0203] The solver module 1903 is adapted to obtain the rotation matrix based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil; construct multiple waveform coefficient expressions based on the offset angle corresponding to the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil; and solve for the electromagnetic field components in the transmitting section coordinate system based on the multiple waveform coefficient expressions corresponding to the multiple receiving coils.

[0204] In an alternative approach, the solver module 1903 is further adapted to:

[0205] By combining the expressions for multiple waveform coefficients corresponding to multiple receiving coils to form an overdetermined system of equations, and solving the overdetermined system of equations, the electromagnetic field components in the transmitter coordinate system are obtained.

[0206] In an alternative approach, the solver module 1903 is further adapted to:

[0207] Based on the source distance of each receiving coil, distance correction processing is performed on the waveform coefficient expressions corresponding to the target receiving coil to obtain the equivalent waveform coefficient expressions; where the target receiving coil includes the receiving coil with the largest source distance and the receiving coil with the smallest source distance.

[0208] By combining the equivalent waveform coefficient expressions corresponding to the target receiving coil and the waveform coefficient expressions corresponding to other receiving coils besides the target receiving coil, the electromagnetic field components can be obtained.

[0209] In an alternative embodiment, the number of receiving coils is three, and the solver module 1903 is further adapted to:

[0210] Based on the minimum source distance and the source distances of other receiving coils, the waveform coefficient expressions corresponding to the receiving coil with the minimum source distance are corrected to obtain the first corrected waveform coefficient expressions.

[0211] Based on the source distance of the maximum source distance and the source distance of other receiving coils, the waveform coefficient expressions corresponding to the receiving coil with the maximum source distance are corrected to obtain the second corrected waveform coefficient expressions.

[0212] Based on the expressions for each first corrected waveform coefficient and each expression for each second corrected waveform coefficient, the expressions for each equivalent waveform coefficient are obtained by combining them.

[0213] In an alternative approach, the solver module 1903 is further adapted to:

[0214] For each component function in the waveform function, the first and second corrected waveform coefficient expressions corresponding to the component function are subjected to different linear combination processes to obtain the equivalent waveform coefficient expressions.

[0215] In an alternative approach, the solver module 1903 is further adapted to:

[0216] The equivalent waveform coefficient expression is determined based on the sum of the first and second corrected waveform coefficient expressions corresponding to the component function, and the subtraction between the first and second corrected waveform coefficient expressions corresponding to the component function.

[0217] In an alternative approach, the solver module 1903 is further adapted to:

[0218] The first correction coefficient is calculated based on the minimum source distance and the source distances of other receiving coils. The first correction coefficient is then multiplied by the waveform coefficient expressions corresponding to the receiving coil with the minimum source distance to obtain the waveform coefficient expressions after the first correction.

[0219] The second correction coefficient is calculated based on the source distance of the maximum source distance and the source distance of other receiving coils. The second correction coefficient is then multiplied by the waveform coefficient expressions corresponding to the receiving coil with the largest source distance to obtain the waveform coefficient expressions after the second correction.

[0220] In one alternative approach, the short section angle difference includes: the well inclination angle difference and the azimuth angle difference between the launch section and the receiver section.

[0221] In an alternative approach, the solver module 1903 is further adapted to:

[0222] The offset angle of the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil are substituted into multiple initial waveform coefficient expressions to obtain multiple waveform coefficient expressions. Among them, the initial waveform coefficient expressions are used to characterize the coupling relationship between electromagnetic field components, elements in the rotation matrix, the offset angle of the transmitting coil, the offset angle of the receiving coil, and waveform coefficients.

[0223] In one alternative approach, the waveform function of the electromagnetic wave signal comprises multiple component functions including multiple different trigonometric functions, which include 0th-order, 1st-order, and 2nd-order trigonometric functions.

[0224] In an alternative approach, the solver module 1903 is further adapted to:

[0225] The first correction factor is calculated based on the square of the minimum source distance and the square of the source distances of other receiving coils; the second correction factor is calculated based on the square of the maximum source distance and the square of the source distances of other receiving coils.

[0226] Alternatively, a first correction factor can be calculated based on the cube of the minimum source distance and the cube of the source distances of other receiving coils; a second correction factor can be calculated based on the cube of the maximum source distance and the cube of the source distances of other receiving coils.

[0227] In summary, the electromagnetic wave component decoupling device for the logging-while-drilling electromagnetic wave tool provided in this embodiment can decouple the electromagnetic wave components to the transmitting coordinate system based on the single-tilt coil transmitting and multi-tilt coil receiving coil system of the logging-while-drilling electromagnetic wave tool, under any relative tilt angle between the transmitting coordinate system and the receiving coordinate system, thereby reducing the difficulty of decoupling the electromagnetic field components under the transmitting coordinate system.

[0228] This application provides a non-volatile computer storage medium storing at least one executable instruction or computer program that enables a processor to perform the operation corresponding to the electromagnetic wave component decoupling method of the logging-while-drilling electromagnetic wave tool in any of the above method embodiments.

[0229] This application provides a computer program product, which includes at least one executable instruction or computer program that enables a processor to perform the operation corresponding to the electromagnetic wave component decoupling method of the drilling electromagnetic wave logging tool in any of the above method embodiments.

[0230] Figure 20 The diagram shows a structural schematic of a computing device provided in an embodiment of this application. The specific embodiments of this application do not limit the specific implementation of the computing device.

[0231] like Figure 20 As shown, the computing device may include: a processor 2002, a communication interface 2004, a memory 2006, and a communication bus 2008.

[0232] The processor 2002, communication interface 2004, and memory 2006 communicate with each other via communication bus 2008. Communication interface 2004 is used to communicate with other network elements, such as clients or other servers. Processor 2002 executes program 2010, specifically performing the relevant steps in the above-described embodiment of the decoupling method for electromagnetic wave components in a drilling electromagnetic logging tool for computing devices.

[0233] Specifically, program 2010 may include program code that includes computer operation instructions.

[0234] The processor 2002 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application. The computing device includes one or more processors, which may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0235] Memory 2006 is used to store program 2010. Memory 2006 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0236] Specifically, program 2010 can be used to cause processor 2002 to execute the electromagnetic wave component decoupling method for the drilling electromagnetic wave logging tool in any of the above method embodiments. The specific implementation of each step in program 2010 can be found in the corresponding descriptions of the steps and units in the embodiments of electromagnetic wave component decoupling for the drilling electromagnetic wave logging tool, and will not be repeated here. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described equipment and modules can be referred to the corresponding process descriptions in the foregoing method embodiments, and will not be repeated here.

[0237] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, the embodiments of this application are not directed to any particular programming language. It should be understood that the content of this application described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of this application.

[0238] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0239] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of the embodiments of this application are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of this application. However, this method of disclosure should not be construed as reflecting an intention that the claimed application requires more features than expressly recited in each claim. Rather, as reflected in the claims, the inventive aspect lies in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0240] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0241] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0242] The various component embodiments of this application can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some or all of the components according to the embodiments of this application. This application can also be implemented as a device or apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such an implementation of this application can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0243] It should be noted that the above embodiments are illustrative of this application and not restrictive, and those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A method for decoupling electromagnetic wave components in a logging-while-drilling electromagnetic wave tool, characterized in that, The logging-while-drilling electromagnetic wave tool includes a transmitting section and a receiving section. The transmitting section is equipped with a transmitting coil for transmitting electromagnetic wave signals, and the receiving section is equipped with multiple receiving coils for acquiring electromagnetic wave signals. The method includes: Obtain the short section angle difference between the transmitting section and the receiving section, and the docking angle difference between the transmitting coil and each receiving coil; For each receiving coil, fit the waveform coefficients of multiple component functions in the waveform function of the electromagnetic wave signal it acquires. The rotation matrix is ​​obtained based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil; The offset angle corresponding to the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil are substituted into multiple initial waveform coefficient expressions to obtain multiple waveform coefficient expressions; wherein, the initial waveform coefficient expressions are used to characterize the coupling relationship between electromagnetic field components, elements in the rotation matrix, the offset angle corresponding to the transmitting coil, the offset angle corresponding to the receiving coil, and waveform coefficients; The electromagnetic field components in the transmitter coordinate system are obtained by solving the multiple waveform coefficient expressions corresponding to the multiple receiving coils.

2. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 1, characterized in that, The step of obtaining the electromagnetic field components in the transmitter coordinate system based on the multiple waveform coefficient expressions corresponding to the multiple receiving coils further includes: By combining the expressions for multiple waveform coefficients corresponding to the multiple receiving coils to form an overdetermined system of equations, and solving the overdetermined system of equations, the electromagnetic field components in the transmitter coordinate system are obtained.

3. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 1, characterized in that, The step of obtaining the electromagnetic field components in the transmitter coordinate system based on the multiple waveform coefficient expressions corresponding to the multiple receiving coils further includes: Based on the source distance of each receiving coil, distance correction processing is performed on each waveform coefficient expression corresponding to the target receiving coil to obtain each equivalent waveform coefficient expression; wherein, the target receiving coil includes the receiving coil with the largest source distance and the receiving coil with the smallest source distance; By combining the equivalent waveform coefficient expressions corresponding to the target receiving coil and the waveform coefficient expressions corresponding to other receiving coils besides the target receiving coil, the electromagnetic field components can be obtained.

4. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 3, characterized in that, The number of receiving coils is three, and the distance correction processing of the waveform coefficient expressions corresponding to the target receiving coil based on the source distance of each receiving coil further includes: Based on the minimum source distance and the source distances of the other receiving coils, the waveform coefficient expressions corresponding to the receiving coil with the minimum source distance are corrected to obtain the first corrected waveform coefficient expressions. Based on the maximum source distance and the source distances of the other receiving coils, the waveform coefficient expressions corresponding to the receiving coil with the largest source distance are corrected to obtain the second corrected waveform coefficient expressions. Based on the first corrected waveform coefficient expressions and the second corrected waveform coefficient expressions, the equivalent waveform coefficient expressions are obtained by combining them.

5. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 4, characterized in that, The step of combining the first corrected waveform coefficient expressions and the second corrected waveform coefficient expressions to obtain the equivalent waveform coefficient expressions further includes: For each component function in the waveform function, the first and second corrected waveform coefficient expressions corresponding to the component function are subjected to different linear combination processes to obtain the equivalent waveform coefficient expressions.

6. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 5, characterized in that, The step of performing different linear combination processes on the first and second corrected waveform coefficient expressions corresponding to the component function to obtain the equivalent waveform coefficient expressions further includes: The equivalent waveform coefficient expression is determined based on the sum of the first and second corrected waveform coefficient expressions corresponding to the component function, and the subtraction of the first and second corrected waveform coefficient expressions corresponding to the component function.

7. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 4, characterized in that, The step of correcting the waveform coefficient expressions corresponding to the receiving coil with the smallest source distance based on the source distances of the other receiving coils to obtain the first corrected waveform coefficient expressions further includes: The first correction coefficient is calculated based on the minimum source distance and the source distance of the other receiving coils. The first correction coefficient is then multiplied by the waveform coefficient expressions corresponding to the receiving coil with the smallest source distance to obtain the waveform coefficient expressions after the first correction. The step of correcting the waveform coefficient expressions corresponding to the receiving coil with the largest source distance based on the source distance of the largest source distance and the source distances of the other receiving coils, to obtain the second corrected waveform coefficient expressions, further includes: The second correction coefficient is calculated based on the maximum source distance and the source distance of the other receiving coils. The second correction coefficient is then multiplied by the waveform coefficient expressions corresponding to the receiving coil with the largest source distance to obtain the waveform coefficient expressions after the second correction.

8. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 1, characterized in that, The short-section angle difference includes: the well inclination angle difference and the azimuth angle difference between the transmitting section and the receiving section.

9. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 1, characterized in that, The waveform function of the electromagnetic wave signal includes multiple component functions, which include multiple different trigonometric functions, including 0th-order, 1st-order and 2nd-order trigonometric functions.

10. The method for decoupling electromagnetic wave components in a drilling electromagnetic logging tool according to claim 7, characterized in that, The step of calculating the first correction coefficient based on the minimum source distance and the source distances of the other receiving coils, and calculating the second correction coefficient based on the maximum source distance and the source distances of the other receiving coils, further includes: A first correction coefficient is calculated based on the square of the minimum source distance and the square of the source distances of the other receiving coils; a second correction coefficient is calculated based on the square of the maximum source distance and the square of the source distances of the other receiving coils. Alternatively, a first correction coefficient can be calculated based on the cube of the minimum source distance and the cube of the source distances of the other receiving coils; a second correction coefficient can be calculated based on the cube of the maximum source distance and the cube of the source distances of the other receiving coils.

11. A device for decoupling electromagnetic wave components in a logging-while-drilling electromagnetic wave tool, characterized in that, The logging-while-drilling electromagnetic wave tool includes a transmitting section and a receiving section. The transmitting section is equipped with a transmitting coil for transmitting electromagnetic wave signals, and the receiving section is equipped with multiple receiving coils for acquiring electromagnetic wave signals. The device includes: The acquisition module is adapted to acquire the short section angle difference between the transmitting section and the receiving section, as well as the docking angle difference between the transmitting coil and each receiving coil; The fitting module is suitable for fitting the waveform coefficients corresponding to multiple component functions in the waveform function of the electromagnetic wave signal acquired by each receiving coil. The solution module is adapted to obtain a rotation matrix based on the short section angle difference and the docking angle difference between the transmitting coil and the receiving coil; substitute the offset angle corresponding to the receiving coil, the rotation matrix, the fitted values ​​of multiple waveform coefficients, and the offset angle of the transmitting coil into multiple initial waveform coefficient expressions to obtain multiple waveform coefficient expressions; wherein, the initial waveform coefficient expressions are used to characterize the coupling relationship between electromagnetic field components, elements in the rotation matrix, the offset angle corresponding to the transmitting coil, the offset angle corresponding to the receiving coil, and waveform coefficients; and solve for the electromagnetic field components in the transmitting section coordinate system based on the multiple waveform coefficient expressions corresponding to the multiple receiving coils.

12. A computing device, characterized in that, include: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the electromagnetic component decoupling method of the logging-while-drilling electromagnetic wave tool as described in any one of claims 1-10.

13. A computer storage medium, characterized in that, The storage medium stores at least one executable instruction, which causes the processor to perform the operation corresponding to the electromagnetic wave component decoupling method of the logging-while-drilling electromagnetic wave tool as described in any one of claims 1-10.

14. A computer program product, characterized in that, It includes at least one executable instruction that causes the processor to perform the operation corresponding to the electromagnetic component decoupling method of the logging-while-drilling electromagnetic wave tool as described in any one of claims 1-10.

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