A transversely isotropic hard formation horizontal shear wave velocity inversion method and device

Abstract

The application relates to a transversely isotropic hard formation horizontal transverse wave velocity inversion method and device. The method comprises the following steps: acquiring waveform data measured by a dipole mode of an array acoustic logging in a target layer section; calculating a measured dispersion curve of a bending wave by using a weighted spectral coherence analysis method based on the waveform data; calculating a bending wave moveout probability density according to the measured dispersion curve of the bending wave; calculating a formation vertical transverse wave velocity according to the bending wave moveout probability density; establishing a target function of horizontal transverse wave velocity inversion of a transversely isotropic formation based on a dispersion equation of the transversely isotropic formation and the formation vertical transverse wave velocity; and inverting the formation horizontal transverse wave velocity according to the target function. The method reduces the target function of the horizontal transverse wave velocity inversion from two dimensions to one dimension, and significantly improves the stability and efficiency of inversion.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration, and in particular to a method and apparatus for inverting horizontal shear wave velocity in laterally isotropic hard formations. Background Technology

[0002] With the continuous deepening of oil and gas exploration and development, unconventional reservoirs have become an important strategic replacement area. Unconventional reservoirs are fine-grained sediments with well-developed laminae and foliation, exhibiting significant lateral isotropic characteristics, meaning that the elastic parameters of the formation show significant differences in the horizontal and vertical directions. When evaluating the rock mechanical parameters and in-situ stress of this type of reservoir, an anisotropic model is required, with the accurate determination of the formation's horizontal shear wave velocity being crucial. In soft formations, the method of inverting the formation's horizontal shear wave velocity using monopole Stoneley waves from array acoustic logging is relatively mature. In hard formations, dipole bending waves are currently mainly used for the inversion of horizontal shear wave velocity; the inversion method is two-dimensional. Summary of the Invention

[0003] To obtain more stable and efficient horizontal shear wave velocity inversion results for laterally isotropic hard formations, embodiments of the present invention provide a method and apparatus for inverting horizontal shear wave velocity in laterally isotropic hard formations.

[0004] In a first aspect, embodiments of this application provide a method for inverting horizontal shear wave velocity in laterally isotropic hard formations, the method comprising:

[0005] Acquire waveform data from array acoustic logging dipole mode measurements in the target layer;

[0006] Based on the waveform data, the measured dispersion curve of the bending wave was calculated using the weighted spectral coherence analysis method.

[0007] Based on the measured dispersion curve of the flexural wave, the probability density of the flexural wave time difference is calculated.

[0008] The vertical shear wave velocity of the formation is calculated based on the bending wave time difference probability density.

[0009] Based on the dispersion equation of the transversely isotropic strata and the vertical shear wave velocity of the strata, an objective function for inverting the horizontal shear wave velocity of the transversely isotropic strata is established.

[0010] The formation horizontal shear wave velocity is obtained by inversion based on the objective function.

[0011] In one or more optional embodiments of this application, the objective function for inverting the horizontal shear wave velocity of the laterally isotropic strata based on the dispersion equation of the laterally isotropic strata and the vertical shear wave velocity of the strata includes:

[0012] Obtain formation density and vertical P-wave velocity;

[0013] Substituting the formation density, the formation vertical P-wave velocity, and the formation vertical S-wave velocity into the dispersion equation, the theoretical dispersion curve of the flexural wave is obtained.

[0014] Based on the measured dispersion curve of the flexural wave and the theoretical dispersion curve of the flexural wave, an objective function for inverting the horizontal shear wave velocity of the transversely isotropic strata is established, as shown in Formula 1:

[0015]

[0016] In the formula, E(V) SH ) is the horizontal shear wave velocity V of the formation. SH The calculated inversion objective function; V(ω) is the measured dispersion curve of the bending wave; V T (ω,V SH ) is the horizontal shear wave velocity V of the formation SH The calculated theoretical dispersion curve of the flexural wave; Ω is the inverted processing frequency band.

[0017] In one or more optional embodiments of this application,

[0018] The step of substituting the formation density, the formation vertical P-wave velocity, and the formation vertical S-wave velocity into the dispersion equation to obtain the theoretical dispersion curve of the flexural wave includes:

[0019] Substituting the formation density, the formation vertical P-wave velocity, and the formation vertical S-wave velocity into the following dispersion equation, formula 2, the wave number at different angular frequencies is solved to obtain the theoretical dispersion curve of the flexural wave:

[0020] D(n,k,ω,C VTI )=0 Formula 2;

[0021] In the formula, n is the sound source order, k is the wave number, ω is the angular frequency, and C VTI The stiffness matrix of the laterally isotropic strata is shown in Formula 3 below;

[0022]

[0023] In the formula, C 11 C 13 C 33 C 44 C 66 These are the stiffness matrix parameters of laterally isotropic strata. Where ρ is the formation density, and V P0 V represents the vertical P-wave velocity of the formation. SV At the same time, V is the vertical shear wave velocity of the formation. SHLet C be the horizontal shear wave velocity of the formation; where, based on the Annie approximation model, C 13 and C 13 It can be calculated using the following formula 4:

[0024]

[0025] In one or more optional embodiments of this application, the step of calculating the measured dispersion curve of the bending wave based on the waveform data using a weighted spectral coherence analysis method includes:

[0026] Substituting the waveform data into the following weighted spectral coherence analysis formula 5, the spectral coherence function of the waveform data within the first preset spectral range and the first preset time difference range is calculated:

[0027]

[0028] In the formula, ρ(ω,s) is the spectral coherence function at a specified frequency and time difference, and X n (ω) represents the spectrum of the waveform data. The conjugate spectrum of the waveform data is given, N is the number of receivers in the array acoustic logging instrument, s is the time difference, ω is the angular frequency, and d is the distance between two adjacent receivers.

[0029] Within the first preset time difference range, the maximum value of the coherence function of the spectrum analyzer at each frequency is extracted as the bending wave time difference at that frequency, and the measured dispersion curve of the bending wave is obtained.

[0030] In one or more optional embodiments of this application, before calculating the measured dispersion curve of the bending wave based on the waveform data using a weighted spectral coherence analysis method, the method further includes:

[0031] The waveform data is preprocessed; wherein the preprocessing includes waveform start time correction, waveform gain reduction, and digital filtering operations.

[0032] In one or more optional embodiments of this application, calculating the probability density of the bending wave time difference based on the measured dispersion curve of the bending wave includes:

[0033] Based on the measured dispersion curve of the flexural wave, the probability density of the flexural wave time difference is calculated within a second preset frequency range using the following formula 6:

[0034]

[0035] In the formula, SPD(s) is the probability density of the corresponding time difference, ω H ω represents the right boundary of the second preset frequency range. L The left boundary of the second preset frequency range, sd (ω) is the average value of the bending wave time difference within the second preset frequency range; σ s dω is the variance of the time difference of the flexural wave within the second preset frequency range, and dω is the frequency sampling interval of the measured dispersion curve of the flexural wave.

[0036] In one or more optional embodiments of this application, calculating the formation vertical shear wave velocity based on the bending wave transit probability density includes:

[0037] Based on the following fitness function formula 7 and the bending wave time difference probability density, the solution for the fitting parameters is obtained:

[0038] F(s)=A(s-s0)βe -α(s-s0) ,s≥s0 Formula 7;

[0039] In the formula, A, α, β, and s0 are all fitting parameters;

[0040] Based on the solution of the fitting parameters, the vertical shear wave time difference of the formation is obtained;

[0041] The vertical shear wave velocity of the formation is calculated based on the vertical shear wave time difference of the formation.

[0042] Secondly, embodiments of this application provide a transversely isotropic hard stratum horizontal shear wave velocity inversion device, the device comprising:

[0043] The first acquisition module is used to acquire waveform data from the target layer array acoustic logging dipole mode measurement.

[0044] The first calculation module is used to calculate the measured dispersion curve of the bending wave based on the waveform data using a weighted spectral coherence analysis method.

[0045] The second calculation module is used to calculate the probability density of the bending wave time difference based on the measured dispersion curve of the bending wave.

[0046] The third calculation module is used to calculate the vertical shear wave velocity of the formation based on the bending wave time difference probability density.

[0047] The first module is used to establish an objective function for inverting the horizontal shear wave velocity of the laterally isotropic strata based on the dispersion equation of the laterally isotropic strata and the vertical shear wave velocity of the strata.

[0048] The first inversion module is used to invert the formation horizontal shear wave velocity according to the objective function.

[0049] Thirdly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described above.

[0050] Fourthly, embodiments of this application provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described above.

[0051] Fifthly, embodiments of this application provide a computer program product containing instructions that, when run on a computer device, cause the computer device to execute the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described above.

[0052] In a sixth aspect, embodiments of this application provide a chip, which includes a processor and a communication interface. The communication interface and the processor are coupled, and the processor is used to run computer programs or instructions to implement the horizontal shear wave velocity inversion method for laterally isotropic hard strata as described above.

[0053] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0054] The method for inverting horizontal shear wave velocity in transversely isotropic hard formations provided in this application obtains flexural wave waveform data through array acoustic logging dipole measurement mode, uses weighted spectral coherence analysis technology to accurately calculate the vertical shear wave velocity of the formation, establishes an objective function for inverting horizontal shear wave velocity in transversely isotropic formations based on the rigidity matrix and dispersion equation of transversely isotropic formations and the vertical shear wave velocity of the formation, and uses a nonlinear fast global optimization algorithm to invert the formation horizontal shear wave velocity. This method reduces the current method of inverting horizontal shear wave velocity using flexural wave dispersion characteristics from two dimensions to one dimension. While ensuring accuracy, it not only improves the stability of the inversion results, but also significantly improves the computational efficiency, making it easy to promote and apply.

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

[0056] Figure 1 This is a flowchart illustrating a method for inverting horizontal shear wave velocity in laterally isotropic hard formations provided in an embodiment of this application.

[0057] Figure 2 This is a schematic diagram of the formation horizontal shear wave velocity inversion results provided in the embodiments of this application;

[0058] Figure 3 This is a schematic diagram of the structure of the horizontal shear wave velocity inversion device for transversely isotropic hard strata provided in the embodiments of this application. Detailed Implementation

[0059] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0060] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or clusters thereof.

[0061] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0062] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0063] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0064] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0065] It should be understood that the sequence number of each step in the following embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0066] To illustrate the technical solution of this application, specific embodiments are described below.

[0067] The inventors discovered that current technologies for determining horizontal shear wave velocity in hard formations primarily utilize dipole curved waves for velocity inversion, and these inversion methods are two-dimensional. Two-dimensional inversion algorithms have low processing efficiency and the inversion results are prone to instability, affecting the accuracy of horizontal shear wave velocity calculations in actual hard formations. Therefore, there is an urgent need for a method for inverting horizontal shear wave velocity in laterally isotropic hard formations to meet the needs of oil and gas exploration and development. Based on this, the inventors, through further research, developed this invention, providing a method and apparatus for inverting horizontal shear wave velocity in laterally isotropic hard formations.

[0068] Example 1

[0069] See Figure 1 This is a method for inverting horizontal shear wave velocity in laterally isotropic hard strata provided in Embodiment 1 of this application, referring to... Figure 1 As shown, the method includes:

[0070] S101: Acquire waveform data from the target layer array acoustic logging dipole mode measurement.

[0071] In this embodiment, step S101 above, acquiring waveform data for dipole measurement of the target layer, refers to using a multipole array acoustic logging instrument to perform measurements in a specific target layer downhole, collecting four-component waveform data in dipole measurement mode. First, a multipole array acoustic logging instrument is needed. This instrument contains multiple receivers. In the well, the instrument is lowered to the target layer to be measured. Then, the dipole measurement mode and other parameters, such as sampling rate and observation time window, are selected. In dipole measurement mode, the instrument simultaneously records waveform data from different components, including amplitude, frequency, and phase information. In this application, the acquired four-component waveform data includes the XX direction component, XY direction component, YY direction component, and YX direction component.

[0072] In this embodiment, the method further includes preprocessing the waveform data, which includes waveform start time correction, waveform gain reduction, and digital filtering. Waveform start time correction ensures that waveform data of different components remain consistent in time by aligning them to a unified time reference. Waveform gain reduction adjusts the waveform amplitude to make the signal and noise amplitudes more balanced, removing interference or noise from the data to improve signal clarity and better reflect the characteristics of the underground medium. The digital filter selectively removes or retains signals within a specific frequency range, removing unwanted frequency components while retaining frequency information of interest to obtain cleaner data.

[0073] S102: Based on waveform data, the measured dispersion curve of the bending wave is calculated using the weighted spectral coherence analysis method.

[0074] In this embodiment of the application, in step S102 above, the measured dispersion curve of the bending wave is calculated based on the waveform data using a weighted spectral coherence analysis method.

[0075] Frequency analysis is performed on the preprocessed four-component waveform data from step S101. Fourier transform or other spectral analysis methods can be used to obtain the spectrum, amplitude, and phase information at different frequencies. For each frequency, the spectral data is substituted into the weighted spectral coherence function as shown in Formula 5 below to calculate the weighted spectral coherence function value:

[0076]

[0077] In the formula, ρ(ω,s) is the spectral coherence function at a specified frequency and time difference, and X n (ω) represents the spectrum of the waveform data. denoted as the conjugate spectrum of the waveform data, N is the number of receivers in the array acoustic logging instrument, s is the time difference, ω is the angular frequency, and d is the distance between two adjacent receivers.

[0078] The maximum value of the weighted spectral coherence function at each frequency point within the flexural wave time difference range is extracted as the flexural wave time difference at that frequency. The obtained flexural wave time difference is plotted as a function of frequency to form a measured dispersion curve, thus obtaining the measured dispersion curve of the flexural wave.

[0079] S103: The probability density of the bending wave time difference is calculated based on the measured dispersion curve of the bending wave.

[0080] In this embodiment of the application, in step S103 above, based on the measured dispersion curve of the flexural wave obtained in step S102, the probability density of the flexural wave time difference is calculated according to the following formula 3 within a preset frequency range at certain intervals (frequency range):

[0081]

[0082] In the formula, SPD(s) is the probability density of the corresponding time difference, ω H ω represents the right boundary of the preset frequency range. L s represents the left boundary of the preset frequency range. d (ω) is the average value of the bending wave time difference within the second preset frequency range; σ s dω is the variance of the time difference of the flexural wave within the second preset frequency range, and dω is the frequency sampling interval of the measured dispersion curve of the flexural wave.

[0083] S104: The vertical shear wave velocity of the formation is calculated based on the probability density of the bending wave time difference.

[0084] In this embodiment of the application, step S104 above, calculating the formation vertical shear wave velocity based on the flexural wave transit probability density, includes: establishing an adaptive function that can fit the flexural wave transit probability density to a certain extent. Based on the following adaptive function formula 7 and the flexural wave transit probability density, the solution for the fitting parameters is obtained:

[0085] F(s)=A(s-s0)βe -α(s-s0) ,s≥s0 Formula 7;

[0086] In the formula, A, α, β, and s0 are all fitting parameters. By fitting the probability density curve of the bending wave transit time and the fitness function, the solutions of the above four fitting parameters are obtained. Based on the fitness function parameters, the vertical shear wave transit time of the formation can be calculated, as shown in Formula 8:

[0087]

[0088] The vertical shear wave velocity of a formation can be calculated based on the conversion relationship between the formation's vertical shear wave time difference and velocity, as shown in Formula 9:

[0089] V SV =1 / s Formula 9;

[0090] S105: Based on the dispersion equation of laterally isotropic strata and the vertical shear wave velocity of the strata, establish the objective function for inverting the horizontal shear wave velocity of laterally isotropic strata.

[0091] S106: Based on the objective function, the formation horizontal shear wave velocity is obtained by inversion.

[0092] In this embodiment of the application, step S105 above, which establishes the objective function for inverting the horizontal shear wave velocity of the laterally isotropic strata based on the dispersion equation of the laterally isotropic strata and the vertical shear wave velocity of the strata, includes:

[0093] Obtain formation density and vertical P-wave velocity;

[0094] Substituting the formation density, the formation vertical P-wave velocity, and the formation vertical S-wave velocity into the following dispersion equation, formula 2, the wave number at different angular frequencies is solved to obtain the theoretical dispersion curve of the flexural wave:

[0095] D(n,k,ω,C VTI )=0 Formula 2;

[0096] In the formula, n is the sound source order, k is the wave number, ω is the angular frequency, and C VTI The stiffness matrix of the laterally isotropic strata is shown in Formula 3 below;

[0097]

[0098] In the formula, C 11 C 13 C 33 C 44 C 66 These are the stiffness matrix parameters of laterally isotropic strata. Where ρ is the formation density, and V P0 V represents the vertical P-wave velocity of the formation. SV At the same time, V is the vertical shear wave velocity of the formation. SH Let C be the horizontal shear wave velocity of the formation; where, based on the Annie approximation model, C 13 and C 13 It can be calculated using the following formula 4:

[0099]

[0100] Based on the measured dispersion curve of the flexural wave and the theoretical dispersion curve of the flexural wave, an objective function for inverting the horizontal shear wave velocity of the transversely isotropic strata is established, as shown in Formula 1:

[0101]

[0102] In the formula, E(V) SH ) is the horizontal shear wave velocity V of the formation. SH The calculated inversion objective function; V(ω) is the measured dispersion curve of the bending wave; V T (ω,V SH ) is the horizontal shear wave velocity V of the formation SH The calculated theoretical dispersion curve of the flexural wave; Ω is the inverted processing frequency band.

[0103] In one specific embodiment, the stiffness matrix of a laterally isotropic stratum can be calculated using formation density, vertical P-wave velocity, vertical S-wave velocity, and horizontal S-wave velocity. The stiffness matrix is ​​directly obtained based on the current formation properties, and the specific calculation formula is shown in Formula 3. When performing calculations based on the laterally isotropic model, it is necessary to determine C. 11 C 13 C 33 C 44 C 66 Five elasticity parameters, of which C 33 C 44 C 66 C can be calculated based on the formation density and the formation's vertical P-wave velocity, vertical S-wave velocity, and horizontal S-wave velocity. 11 C 13 The parameters mentioned above cannot be obtained directly and need to be estimated using a prediction model. In this scheme, the Annie approximation model is used to obtain C. 11 With C 13 Using C 33 C 44 C 66 The calculation expression is as follows: The obtained rigid matrix parameters of the transversely isotropic formation, well fluid density, and fluid velocity, etc., are substituted into the dispersion equation for multipole acoustic wave propagation in the transversely isotropic formation, as shown in Equation 2. The wave number at different angular frequencies is solved using the dispersion equation to obtain the theoretical dispersion curve of the transversely isotropic formation shear wave velocity, which includes the variable.

[0104] Using the measured dispersion curve of the flexural wave obtained in step S102 and the obtained theoretical dispersion curve, an objective function for the inversion of the horizontal shear wave velocity in the transversely isotropic strata is established, as shown in Formula 1. This objective function measures the residual between the theoretical dispersion curve and the measured dispersion curve during the inversion calculation.

[0105] In this embodiment, an objective function for inverting the horizontal shear wave velocity of a laterally isotropic formation is obtained. When the objective function is minimized, the corresponding formation horizontal shear wave velocity is the inverted target formation horizontal shear wave velocity. Within a given range of horizontal shear wave velocity values, a nonlinear fast global optimization algorithm is used to find the inversion result of the horizontal shear wave velocity and the optimal solution. No restrictions are placed on the nonlinear fast global optimization algorithm used. In a specific embodiment, the least squares method is used to find the minimum value of the objective function as the formation horizontal shear wave velocity.

[0106] The results of the horizontal shear wave velocity inversion in the formation are shown in the figure below. Figure 2As shown, the lithology, porosity, and resistivity curves in columns one through three are data that can be directly measured from well logging. In the fourth channel, DTSV represents the vertical shear wave velocity obtained in step S104, and DTSH represents the horizontal shear wave velocity obtained in step S106. The fifth channel shows the shear wave anisotropy, representing the difference between DTSH and DTSV. This scheme provides a stable horizontal shear wave velocity inversion method, improving the stability of the inversion results while maintaining accuracy. Vertical and horizontal shear wave velocities are crucial foundational data for geological exploration; stable inversion results help construct more detailed subsurface models.

[0107] Example 2

[0108] Based on the same inventive concept, this application also provides a transversely isotropic hard stratum horizontal shear wave velocity inversion device, referring to... Figure 3 As shown, the device includes:

[0109] The first acquisition module 101 is used to acquire waveform data of the target layer array acoustic logging dipole mode measurement;

[0110] The first calculation module 102 is used to calculate the measured dispersion curve of the bending wave based on the waveform data using a weighted spectral coherence analysis method.

[0111] The second calculation module 103 is used to calculate the probability density of the bending wave time difference based on the measured dispersion curve of the bending wave.

[0112] The third calculation module 104 is used to calculate the vertical shear wave velocity of the formation based on the bending wave time difference probability density.

[0113] The first module 105 is used to establish an objective function for inverting the horizontal shear wave velocity of the laterally isotropic strata based on the dispersion equation of the laterally isotropic strata and the vertical shear wave velocity of the strata.

[0114] The first inversion module 106 is used to invert the formation horizontal shear wave velocity according to the objective function.

[0115] Example 3

[0116] Based on the same inventive concept, this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described in Embodiment 1 above.

[0117] Example 4

[0118] Based on the same inventive concept, this application also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described in Embodiment 1 above.

[0119] Example 5

[0120] Based on the same inventive concept, this application also provides a computer program product containing instructions that, when the computer program product is run on a computer device, cause the computer device to execute the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described in Embodiment 1 above.

[0121] Example 6

[0122] Based on the same inventive concept, this application also provides a chip, which includes a processor and a communication interface. The communication interface and the processor are coupled. The processor is used to run computer programs or instructions to implement the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described in Embodiment 1 above.

[0123] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above device can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here. If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. A computer-readable medium can include at least: any entity or device capable of carrying computer program code, a recording medium, a computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.

[0124] The implementation of all or part of the processes in the methods of the above embodiments can also be accomplished by a computer program product. When the computer program product is run on a computer device, it enables the computer device to execute the steps in the above method embodiments.

[0125] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0126] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0127] In the embodiments provided in this application, it should be understood that the disclosed apparatus / computer devices and methods can be implemented in other ways. For example, the apparatus / computer device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0128] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0129] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for inverting horizontal shear wave velocity in laterally isotropic hard strata, characterized in that, include: Acquire waveform data from array acoustic logging dipole mode measurements in the target layer; Based on the waveform data, the measured dispersion curve of the bending wave is calculated using the weighted spectral coherence analysis method. Based on the measured dispersion curve of the flexural wave, the probability density of the flexural wave time difference is calculated. The vertical shear wave velocity of the formation is calculated based on the bending wave time difference probability density. Obtain formation density and vertical P-wave velocity; Substituting the formation density, the formation vertical P-wave velocity, and the formation vertical S-wave velocity into the dispersion equation based on transversely isotropic formations, the theoretical dispersion curve of the bending wave is obtained. Based on the measured dispersion curve and the theoretical dispersion curve of the flexural wave, an objective function for inverting the horizontal shear wave velocity in laterally isotropic hard strata is established, as shown in Formula 1: ； In the formula, It is the horizontal shear wave velocity of the formation. The calculated inversion objective function; The measured dispersion curve of the bending wave; To measure the horizontal shear wave velocity of the formation The calculated theoretical dispersion curve of the bending wave; The processing frequency band for inversion; The formation horizontal shear wave velocity is obtained by inversion based on the objective function.

2. The method as described in claim 1, characterized in that, The process of substituting the formation density, the formation vertical P-wave velocity, and the formation vertical S-wave velocity into the dispersion equation based on transversely isotropic formations to obtain the theoretical dispersion curve of flexural waves includes: Substituting the formation density, the formation vertical P-wave velocity, and the formation vertical S-wave velocity into the following dispersion equation, formula 2, the wave number at different angular frequencies is solved to obtain the theoretical dispersion curve of the flexural wave: Official 2; In the formula, n is the sound source order, and k is the wave number. Angular frequency, The stiffness matrix of the laterally isotropic strata is shown in Formula 3 below; Official 3; In the formula, , , , , These are the stiffness matrix parameters of laterally isotropic strata. , , ,in For the density of the formation, The vertical P-wave velocity of the strata. The vertical shear wave velocity of the formation, The velocity is the horizontal shear wave velocity of the formation; where, based on the Annie approximation model, and It can be calculated using the following formula 4: Official 4.

3. The method as described in claim 1, characterized in that, The calculation of the measured dispersion curve of the flexural wave based on the waveform data using the weighted spectral coherence analysis method includes: Substituting the waveform data into the following weighted spectral coherence analysis formula 5, the spectral coherence function of the waveform data within the first preset spectral range and the first preset time difference range is calculated: Official 5; In the formula, For a given frequency and time difference, the spectral coherence function, The spectrum of the waveform data. The conjugate spectrum of the waveform data is given, where N is the number of receivers in the array acoustic logging instrument, and s is the time difference. denoted as angular frequency, and d as the distance between two adjacent receivers; Within the first preset time difference range, the maximum value of the coherence function of the spectrum analyzer at each frequency is extracted as the bending wave time difference at that frequency, and the measured dispersion curve of the bending wave is obtained.

4. The method as described in claim 1, characterized in that, Before calculating the measured dispersion curve of the flexural wave using the weighted spectral coherence analysis method based on the waveform data, the method further includes: The waveform data is preprocessed; wherein the preprocessing includes waveform start time correction, waveform gain reduction, and digital filtering operations.

5. The method as described in claim 1, characterized in that, The step of calculating the probability density of the flexural wave time difference based on the measured dispersion curve of the flexural wave includes: Based on the measured dispersion curve of the flexural wave, the probability density of the flexural wave time difference is calculated within a second preset frequency range using the following formula 6: Official 6; In the formula, SPD(s) is the probability density of the corresponding time difference. The right boundary of the second preset frequency range. The left boundary of the second preset frequency range. The average value of the bending wave time difference within the second preset frequency range; The variance of the bending wave time difference within the second preset frequency range. The frequency sampling interval is the measured dispersion curve of the bending wave.

6. The method as described in claim 1, characterized in that, The step of calculating the vertical shear wave velocity of the formation based on the flexural wave time difference probability density includes: Based on the following fitness function formula 7 and the bending wave time difference probability density, the solution for the fitting parameters is obtained: Official 7; In the formula, A, , , All are fitted parameters; Based on the solution of the fitting parameters, the vertical shear wave time difference of the formation is obtained; The vertical shear wave velocity of the formation is calculated based on the vertical shear wave time difference of the formation.

7. A transversely isotropic hard stratum horizontal shear wave velocity inversion device, characterized in that, include: The first acquisition module is used to acquire waveform data from the target layer array acoustic logging dipole mode measurement. The first calculation module is used to calculate the measured dispersion curve of the bending wave based on the waveform data using a weighted spectral coherence analysis method. The second calculation module is used to calculate the probability density of the bending wave time difference based on the measured dispersion curve of the bending wave. The third calculation module is used to calculate the vertical shear wave velocity of the formation based on the bending wave time difference probability density. The first module is used to obtain the formation density and the vertical P-wave velocity of the formation; Substituting the formation density, the formation vertical P-wave velocity, and the formation vertical S-wave velocity into the dispersion equation based on transversely isotropic formations, the theoretical dispersion curve of the bending wave is obtained. Based on the measured dispersion curve and the theoretical dispersion curve of the flexural wave, an objective function for inverting the horizontal shear wave velocity in laterally isotropic hard strata is established, as shown in Formula 1: Official 1; In the formula, It is the horizontal shear wave velocity of the formation. The calculated inversion objective function; The measured dispersion curve of the bending wave; To measure the horizontal shear wave velocity of the formation The calculated theoretical dispersion curve of the bending wave; The processing frequency band for inversion; The first inversion module is used to invert the formation horizontal shear wave velocity according to the objective function.

8. A computer-readable storage medium storing instructions that, when executed on a terminal, cause the terminal to perform the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described in any one of claims 1-6.

9. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described in any one of claims 1-6.

10. A computer program product containing instructions that, when run on a computer device, causes the computer device to perform the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described in any one of claims 1-6.

11. A chip comprising a processor and a communication interface, the communication interface being coupled to the processor, the processor being configured to run a computer program or instructions to implement the horizontal shear wave velocity inversion method for laterally isotropic hard formations as described in any one of claims 1-6.

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