Estimation method of VTI medium shear wave anisotropy parameter based on shear wave inversion

Abstract

The present application relates to a VTI medium shear wave anisotropy parameter estimation method based on seismic shear wave inversion. It includes obtaining seismic shear wave data and well logging data; determining shear wave anisotropy parameter well data according to the well logging data; determining VTI medium shear wave inversion initial model according to the seismic shear wave data and the shear wave anisotropy parameter well data; determining synthetic data according to the VTI medium shear wave reflection coefficient improved approximate equation; determining the objective function according to the seismic shear wave data, the synthetic data and the VTI medium shear wave inversion initial model; determining the VTI medium shear wave inversion result by using the objective function; and determining the VTI medium shear wave anisotropy parameter according to the VTI medium shear wave inversion result. The present application inverses the shear wave impedance and the horizontal shear wave velocity, and obtains the relationship between the shear wave impedance and the vertical shear wave velocity according to the well logging data, so as to estimate the shear wave anisotropy parameter, and effectively realize the seismic shear wave inversion for anisotropic medium.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas field development, and particularly relates to a VTI medium shear wave anisotropy parameter estimation method based on seismic shear wave inversion. BACKGROUND

[0002] During the propagation of seismic waves in the underground medium, the amplitude and velocity are significantly affected by anisotropy.

[0003] In the prior art, AVO analysis and inversion based on P-wave anisotropy are more common and have been widely used in oil and gas reservoir prediction and fluid identification. However, due to the large number of parameters to be inverted for P-waves, simultaneous inversion of multiple parameters has high ill-posedness.

[0004] In the prior art, it has been pointed out that the density and shear wave velocity of the formation can be accurately and effectively inverted by using pure shear waves, but there is still a lack of effective method for seismic shear wave inversion of anisotropic media.

[0005] In view of the problem in the prior art that multiple parameters cannot be simultaneously inverted based on P-waves with high ill-posedness when problems occur, a VTI medium shear wave anisotropy parameter estimation method based on seismic shear wave inversion is needed. SUMMARY

[0006] To solve the above problems in the prior art, the embodiments of the present application provide a VTI medium shear wave anisotropy parameter estimation method based on seismic shear wave inversion.

[0007] The embodiments of the present application provide a VTI medium shear wave anisotropy parameter estimation method based on seismic shear wave inversion, which comprises obtaining seismic shear wave data and logging data; determining shear wave anisotropy parameter well data according to the logging data; determining a VTI medium shear wave inversion initial model according to the seismic shear wave data and the shear wave anisotropy parameter well data; determining synthetic data according to the VTI medium shear wave inversion initial model and a VTI medium shear wave reflection coefficient improved approximation equation; determining a target function according to the seismic shear wave data, the synthetic data and the VTI medium shear wave inversion initial model; updating parameters in the VTI medium shear wave inversion initial model by using the target function to determine a VTI medium shear wave inversion result; and determining VTI medium shear wave anisotropy parameters according to the VTI medium shear wave inversion result.

[0008] According to an aspect of the embodiments herein, determining the shear wave anisotropy parameter well data comprises determining sampling points in the well data having shale content exceeding a predetermined threshold as VTI medium layers; calculating elastic tensor well data for each sampling point in the VTI medium layers; determining equivalent VTI medium elastic tensor well data for each sampling point from the elastic tensor well data for each sampling point using Backus formula; and calculating the shear wave anisotropy parameter well data according to the following formula: wherein γ is the shear wave anisotropy parameter well data, is the equivalent VTI medium stiffness matrix parameter.

[0009] According to an aspect of the embodiments herein, determining the VTI medium shear wave inversion initial model from the seismic shear wave data and the shear wave anisotropy parameter well data comprises converting the seismic shear wave data into angle domain seismic shear wave data to determine a VTI medium shear wave angle domain stack profile; well-to-seismic calibration of the VTI medium shear wave angle domain stack profile and the well data to convert the well data into time domain well data; obtaining the vertical shear wave velocity, the density and the shear wave anisotropy parameter well data from the time domain well data and performing data smoothing and layer-wise extrapolation to obtain initial vertical shear wave velocity, initial density and initial shear wave anisotropy parameter well data; and calculating the VTI medium shear wave inversion initial model from the initial vertical shear wave velocity, the initial density and the initial shear wave anisotropy parameter well data using the following formula:

[0010]

[0011]

[0012] wherein, is the initial shear wave impedance, is the initial horizontal shear wave velocity, ρ prior is the initial density, is the initial vertical shear wave velocity, γ prior is the initial shear wave anisotropy parameter well data.

[0013] According to an aspect of the embodiments herein, determining the synthetic data from the VTI medium shear wave inversion initial model and the VTI medium shear wave reflection coefficient improved approximation equation comprises constructing a multi-angle wavelet convolution matrix from the seismic shear wave data; calculating the VTI medium shear wave reflection coefficient for different shear wave incidence angles using the VTI medium shear wave reflection coefficient improved approximation equation from the VTI medium shear wave inversion initial model and the shear wave incidence angle of the seismic shear wave data:

[0014] wherein θ is the shear wave incidence angle, (Z S )i is the i-th S-wave impedance calculated according to the initial model of VTI medium S-wave inversion, (V S ) i+1 is the i+1-th S-wave impedance, (V SH90 ) i is the i-th horizontal S-wave velocity calculated according to the initial model of VTI medium S-wave inversion, V SH90 ≈V S0 ·e γ , V S0 is the vertical S-wave velocity, and γ is the S-wave anisotropy parameter; and the product of the VTI medium S-wave reflection coefficient and the multi-angle wavelet convolution matrix is used to determine the synthetic data.

[0015] According to an aspect of the embodiments herein, the method comprises determining the objective function using the formula: J(m) = [G(m) - d] T [G(m) - d] + μ(m - m prior ) T (m - m prior ), wherein J(m) is the objective function, G(m) is the synthetic data, d is seismic data composed of M different angle seismic trace sets, μ is a regularization coefficient, m = [ln(Z S ), ln(V SH90 )] T is a model parameter vector; m prior is a prior model.

[0016] According to an aspect of the embodiments herein, updating the parameters in the initial model of VTI medium S-wave anisotropy parameter inversion using the objective function comprises: deriving the model parameters in the objective function; determining the update amount of the model parameters and the data residual of model training; and determining the VTI medium S-wave inversion result when the data residual is less than a preset threshold or reaches a maximum number of iterations.

[0017] According to an aspect of the embodiments herein, the method comprises: obtaining S-wave impedance logging data and vertical S-wave velocity logging data from real-time logging data; fitting and analyzing the petrophysical relationship between the S-wave impedance logging data and the vertical S-wave velocity logging data; determining a vertical S-wave velocity estimate value according to the petrophysical relationship and the S-wave impedance inversion result; and determining the S-wave anisotropy parameter according to the vertical S-wave velocity estimate value and the horizontal S-wave velocity inversion result using the formula: wherein γ is the anisotropy parameter, is the vertical S-wave velocity estimate value, and V SH90 is the horizontal S-wave velocity inversion result.

[0018] The embodiment of the present application provides a device for estimating VTI medium shear wave anisotropy parameters based on shear wave inversion, which comprises: a data acquisition unit configured to acquire seismic shear wave data and logging data; a data determination unit configured to determine shear wave anisotropy parameter well data according to the logging data; an initial model determination unit configured to determine a VTI medium shear wave inversion initial model according to the seismic shear wave data and the shear wave anisotropy parameter well data; a synthetic data determination unit configured to determine synthetic data according to the VTI medium shear wave inversion initial model and a VTI medium shear wave reflection coefficient improved approximation equation; a target function determination unit configured to determine a target function according to the seismic shear wave data, the synthetic data and the VTI medium shear wave inversion initial model; a VTI medium shear wave inversion result determination unit configured to update parameters in the VTI medium shear wave inversion initial model by using the target function, and determine a VTI medium shear wave inversion result; and a VTI medium shear wave anisotropy parameter determination unit configured to determine VTI medium shear wave anisotropy parameters according to the VTI medium shear wave inversion result.

[0019] The embodiment of the present application also provides a computer device, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, and the processor implements the method for estimating VTI medium shear wave anisotropy parameters based on shear wave inversion when executing the computer program.

[0020] The embodiment of the present application also provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the method for estimating VTI medium shear wave anisotropy parameters based on shear wave inversion.

[0021] The present application establishes an initial model according to seismic shear wave data and logging data, and inverses shear wave impedance and horizontal shear wave velocity; obtains the relationship between shear wave impedance and vertical shear wave velocity according to logging data, and finally estimates shear wave anisotropy parameters from horizontal shear wave velocity and vertical shear wave velocity, thereby effectively realizing shear wave inversion for anisotropic medium. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0023] Figure 1 The flowchart of the method for estimating VTI medium shear wave anisotropy parameters based on shear wave inversion is shown.

[0024] Figure 2 A method flow chart for determining shear anisotropy parameter well data is shown in the embodiment herein;

[0025] Figure 3 A method flow chart for determining VTI medium shear wave inversion initial model is shown in the embodiment herein;

[0026] Figure 4 A method flow chart for determining synthetic data is shown in the embodiment herein;

[0027] Figure 5 A method flow chart for determining VTI medium shear wave inversion result is shown in the embodiment herein;

[0028] Figure 6 A method flow chart for determining VTI medium shear anisotropy parameter is shown in the embodiment herein;

[0029] Figure 7 A structural schematic diagram of a VTI medium shear anisotropy parameter estimation device based on seismic shear wave inversion is shown in the embodiment herein;

[0030] Figure 8 A specific structural schematic diagram of a VTI medium shear anisotropy parameter estimation device based on seismic shear wave inversion is shown in the embodiment herein;

[0031] Figure 9A A VTI medium shear wave stack profile of 10° is shown in the embodiment herein;

[0032] Figure 9B A VTI medium shear wave stack profile of 20° is shown in the embodiment herein;

[0033] Figure 9C A VTI medium shear wave stack profile of 30° is shown in the embodiment herein;

[0034] Figure 10 An initial vertical shear wave velocity, initial density and initial shear anisotropy parameter are shown in the embodiment herein;

[0035] Figure 11A An initial shear wave impedance is shown in the embodiment herein;

[0036] Figure 11B A horizontal shear wave velocity initial model is shown in the embodiment herein;

[0037] Figure 12A A shear wave impedance inversion profile is shown in the embodiment herein;

[0038] Figure 12B Fig. 4 shows a schematic diagram of a horizontal shear wave velocity inversion profile according to an embodiment of the present disclosure;

[0039] Figure 13 Fig. 5 shows a schematic diagram of a vertical shear wave velocity inversion profile and an inversion profile of anisotropic parameters according to an embodiment of the present disclosure;

[0040] Figure 14 Fig. 6 shows a schematic diagram of a computer device according to an embodiment of the present disclosure.

[0041] List of Symbols:

[0042] 701, a data acquisition unit;

[0043] 702, a data determination unit;

[0044] 7021, a well-to-seismic calibration module;

[0045] 7022, an elastic tensor well data determination module;

[0046] 703, an initial model determination unit;

[0047] 704, a synthetic data determination unit;

[0048] 7041, a VTI medium shear wave reflection coefficient improved approximation equation determination module;

[0049] 705, an objective function determination unit;

[0050] 706, a VTI medium shear wave inversion result determination unit;

[0051] 707, a VTI medium shear wave anisotropic parameter determination unit;

[0052] 1402, a computer device;

[0053] 1404, a processor;

[0054] 1406, a memory;

[0055] 1408, a driving mechanism;

[0056] 1410, an input / output module;

[0057] 1412, an input device;

[0058] 1414, an output device;

[0059] 1416, a presentation device;

[0060] 1418, a graphical user interface;

[0061] 1420, a network interface;

[0062] 1422, communication link;

[0063] 1424, communication bus. DETAILED DESCRIPTION

[0064] In order to better understand the technical solutions in the specification, the technical solutions in the specification will be described clearly and completely in the following with reference to the drawings in the embodiments. Obviously, the described embodiments are only some of the embodiments, but not all the embodiments. Based on the embodiments herein, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection.

[0065] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, device, product or apparatus including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to the process, method, product or apparatus.

[0066] The specification provides method operation steps as described in the embodiments or flowcharts, but can include more or less operation steps based on routine or non-creative labor. The order of steps listed in the embodiments is only one of the many step execution orders, and does not represent the only execution order. In actual system or device product execution, the method order shown in the embodiments or the drawings can be executed in sequence or in parallel.

[0067] The VTI medium herein is an anisotropic medium, in which the elastic properties (e.g., wave velocity) vary with different measurement directions. Specifically, the seismic shear wave splits into two columns of waves with different propagation speeds and perpendicular polarization directions after passing through the anisotropic medium. Elastic waves propagate at different speeds in different directions when passing through an anisotropic medium. Compared with the seismic P-wave, the seismic S-wave is more sensitive to the changes in the S-wave velocity, density and anisotropy of the underlying layer. Therefore, the anisotropic medium is closer to the actual situation of the underground rock layer than the isotropic medium.

[0068] Figure 1 The flowchart shows a VTI medium S-wave anisotropy parameter estimation method based on seismic S-wave inversion according to an embodiment of the present application. Specifically, the method comprises the following steps:

[0069] In step 101, seismic shear wave data and logging data are acquired. In this step, the logging data reflect formation and geological information. The logging data are response curves related to underground lithology and underground physical properties in the wellbore range measured based on depth. Specifically, the logging data include P-wave velocity, S-wave velocity, density, shale content, porosity and water saturation curves. The seismic shear wave data are derived from seismic data, which are responses to underground reflection interfaces in the time domain.

[0070] In this step, the seismic data acquired are prestack shear wave seismic data of the target work area, and the prestack shear wave seismic data are preprocessed to further acquire the common-angle stack profile of the target work area. Specifically, the prestack shear wave seismic data of the target work area are subjected to NMO correction and migration processing, CMP gathers are flattened using the NMO velocity to obtain CIP, the shear wave CIP is converted from the offset domain to the angle domain, and the seismic data in a certain angle interval are further stacked to obtain VTI medium shear wave angle-dependent stack profiles at different angles. In this specification, in the process of shear wave inversion, only small and medium angle data are needed to reliably invert the shear wave impedance and horizontal shear wave velocity. Therefore, in one embodiment of the specification, the VTI medium shear wave angle-dependent stack profiles at 10°, 20° and 30° are used as the input of the VTI medium shear wave inversion initial model. The VTI medium shear wave angle-dependent stack profiles at 10°, 20° and 30° can be seen from FIG. 1. Figures 9A-9C

[0071] The wavelets of the VTI medium shear wave angle-dependent stack profiles at different angles are further extracted to obtain a wavelet convolution matrix at different angles. The seismic shear wave data and the logging data are calibrated, and further combined with the seismic horizon information to construct a VTI medium shear wave inversion initial model using the interpolation extrapolation method. The initial model includes initial shear wave impedance and initial horizontal shear wave velocity.

[0072] ​Step 102, according to the logging data, determine the shear wave anisotropy parameter well data. The purpose of the logging data in this step is the logging data of the target area, including the longitudinal wave velocity, the shear wave velocity, the density, the shale content, the porosity and the water saturation curve. In this step, the VTI medium layer is first determined according to the logging data, and the logging data of the logging sampling point of the VTI medium layer is further determined to calibrate the well and the earthquake. Specifically, the horizontal shear wave velocity is included in the logging data, the velocity field is constructed according to the horizontal shear wave velocity in the logging data, the depth domain logging data is converted into time domain data, and the time domain logging data is further synthesized to match the time domain seismic shear wave data at the corresponding position, that is, the depth domain logging data is matched with the time domain seismic shear wave data, and the well and earthquake calibration is completed. Further, the anisotropy parameter well data of the VTI medium layer is determined.

[0073] Step 103, according to the seismic shear wave data, the shear wave anisotropy parameter well data, determine the VTI medium shear wave inversion initial model. In this step, the vertical shear wave velocity, the density, the shear wave anisotropy parameter well data of the VTI medium layer determined in step 102 are smoothed according to the window size, and the initial vertical shear wave velocity, the initial density, the initial shear wave anisotropy parameter are obtained by extrapolation along the layer, and the initial model of the shear wave impedance and the horizontal shear wave velocity is further calculated, and the initial model of the shear wave impedance and the horizontal shear wave velocity forms the VTI medium shear wave inversion initial model. The description of the VTI medium shear wave inversion initial model determined in this step is specifically described in Figure 3 .

[0074] Step 104, according to the VTI medium shear wave inversion initial model, the VTI medium shear wave reflection coefficient improved approximation equation, determine the synthetic data. In this step, according to the VTI medium shear wave reflection coefficient accurate formula, the VTI medium shear wave reflection coefficient improved approximation equation is obtained. The VTI medium shear wave reflection coefficient accurate formula is the reflection coefficient equation of single interface. The process of VTI medium shear wave reflection coefficient accurate formula, VTI medium shear wave reflection coefficient improved approximation equation and synthetic data will be described in detail in Figure 2 .

[0075] Step 105, according to the seismic shear wave data, the synthetic data and the VTI medium shear wave inversion initial model, determine the objective function. In this step, the objective function in the inversion process is determined by using the following formula:

[0076] J(m)=[G(m)-d] T [G(m)-d]+μ(m-m prior ) T (m-m prior), where J(m) is the objective function, G(m) is the synthetic data, d is seismic data composed of M different angle seismic gathers, μ represents a regularization term coefficient proportional to noise level, m = [ln(Z s ), ln(V SH 90 )] T represents model parameters including S-wave impedance and horizontal S-wave velocity, μ(m-m prior ) T (m-m prior ) is a regularization term; m pior is a prior model, G(m)-d represents the difference between the synthetic seismic record and the real seismic data, m prior represents model parameters.

[0077] In this step, the objective function is used to analyze the error between the synthetic data G(m) and the real seismic data, and the model parameters are continuously adjusted according to the error, so that the error of the objective function is continuously converged, until the error value converges to a certain range, and the model parameters in the current objective function are solved. In some embodiments of the present specification, a least squares error function is constructed as the objective function of VTI medium S-wave inversion initial model, and the objective function is solved to obtain the model parameters.

[0078] Step 106, updating the parameters in the VTI medium S-wave inversion initial model by using the objective function to determine the VTI medium S-wave inversion result. In this step, the model parameters include S-wave impedance and horizontal S-wave velocity. Each time the objective function is calculated, the S-wave impedance and horizontal S-wave velocity in the VTI medium S-wave inversion initial model are iteratively updated. When the value of the objective function converges to a preset threshold range, it is determined that the iteration of the objective function is completed, the model parameters at this time are solved, and the VTI medium S-wave inversion result is determined.

[0079] Step 107, determining the VTI medium S-wave anisotropy parameter according to the VTI medium S-wave inversion result. The VTI medium S-wave inversion result includes S-wave impedance well inversion result and horizontal S-wave velocity inversion result. This step further determines the description of the VTI medium S-wave anisotropy parameter according to the inversion result, which will be described in detail in Figure 6 .

[0080] Figure 2 The method flow chart for determining the S-wave anisotropy parameter well data is shown in the figure, which includes the following steps:

[0081] Step 201, determining the sampling points with shale content exceeding a preset threshold value in the logging data as VTI medium layer. In this step, the logging sampling points with shale content exceeding the set threshold value are selected from the logging data as VTI medium layer. The logging sampling points with shale content less than or equal to the set threshold value are determined as isotropic layer. The set threshold value can be 40%, 45% or other data. In some embodiments of the present specification, the initial anisotropy parameters of the logging sampling points determined as VTI medium layer are set as: δ = 0.01, ε = 0.04, γ = 0.11.

[0082] Step 202, calculating the elastic tensor well data of each sampling point in the VTI medium layer. In this step, the elastic tensor well data of each sampling point in the VTI medium layer is calculated by using the Thomsen weak anisotropy theory.

[0083] Step 203, determining the equivalent VTI medium elastic tensor well data of each sampling point according to the elastic tensor well data of each sampling point by using the Backus formula. The Backus average calculation formula is as follows:

[0084]

[0085] wherein, V i is the volume fraction of the i th sampling point in the sliding window, and m is the number of sampling points in the sliding window. In the above formula (1), represents the equivalent stiffness matrix parameters.

[0086] Step 204, calculating the shear wave anisotropy parameter well data according to the following formula:

[0087] wherein, γ is the shear wave anisotropy parameter well data calculated according to the equivalent VTI medium elastic tensor well data, is the equivalent VTI medium stiffness matrix parameter.

[0088] Figure 3 The method flow chart for determining the initial model of VTI medium shear wave inversion is shown in the figure, which includes the following steps:

[0089] Step 301, converting the seismic shear wave data into angle domain seismic shear wave data to determine the VTI medium shear wave angle division stacking profile. In some embodiments of the present specification, the shear wave velocity is converted into time domain data, and the angle domain seismic shear wave data is partially angle stacked to obtain the shear wave angle division stacking profile. The shear wave angle gathers within a certain angle range are stacked to obtain the shear wave angle division stacking profiles of 10°, 20° and 30°.

[0090] ​Step 302, well-to-seismic calibration is performed on the VTI medium shear wave angle-dependent stack section and the logging data, and the logging data is converted into time-domain logging data. In the present specification, well-to-seismic calibration can be performed according to the VTI medium shear wave angle-dependent stack section and the logging data. Specifically, the logging data includes the vertical shear wave velocity and the density, a velocity field is constructed according to the vertical shear wave velocity in the logging data, the depth-domain logging data is converted into time-domain data, and the time-domain logging data is further matched with the time-domain seismic shear wave data at the corresponding position, i.e., the depth-domain logging data is matched with the time-domain seismic shear wave data, and the well-to-seismic calibration is completed.

[0091] Step 303, the vertical shear wave velocity, the density and the shear wave anisotropy parameter well data in the converted time-domain logging data are obtained, and data smoothing processing and layer-by-layer extrapolation are performed to obtain initial vertical shear wave velocity, initial density and initial shear wave anisotropy parameter well data. The initial vertical shear wave velocity, the initial density and the initial shear wave anisotropy parameter are shown in the following table. Figure 10

[0092] Specifically, the converted time-domain vertical shear wave velocity, density and shear wave anisotropy parameter well data are subjected to data smoothing processing and layer-by-layer extrapolation according to a preset window size to obtain initial vertical shear wave velocity, initial density and initial shear wave anisotropy parameter well data. Specifically, the vertical shear wave velocity is subjected to smoothing processing and layer-by-layer extrapolation to obtain initial vertical shear wave velocity The density is subjected to smoothing processing and layer-by-layer extrapolation to obtain initial density prior The shear wave anisotropy parameter is subjected to smoothing processing and layer-by-layer extrapolation to obtain initial shear wave anisotropy parameter prior .

[0093] Step 304, according to the initial vertical shear wave velocity, the initial density and the initial shear wave anisotropy parameter well data, the initial VTI medium shear wave inversion model is calculated by using the following formula respectively:

[0094]

[0095]

[0096] wherein, ρ is the initial shear wave impedance, is the initial horizontal shear wave velocity, is the initial vertical shear wave velocity, γ prior is the initial shear wave anisotropy parameter well data, ρ prior is the initial density. The initial shear wave impedance calculated by the above formula is the product of the initial density and the initial vertical shear wave velocity. The initial shear wave impedance model and the initial horizontal shear wave velocity are shown in the following table.​Figure 11A and Figure 11B The initial shear wave impedance and the initial horizontal shear wave velocity constitute the initial model of the VTI medium shear wave inversion in this paper.

[0097] Figure 4 A method flow chart for determining synthetic data according to an embodiment of the present application is shown in FIG. 4, comprising the following steps:

[0098] Step 401, extract different angle seismic wavelets from the seismic shear wave data, and construct a multi-angle wavelet convolution matrix. This step can select seismic shear wave data of different incident angles, such as 10°, 20°, and 30° seismic shear wave data, from the shear wave seismic data in step 101. Using different angle seismic shear wave data, construct a VTI medium shear wave angle-dependent stacking profile. As shown in FIG. 2, Figure 9A 、 Figure 9B 、 Figure 9C The VTI medium shear wave angle-dependent stacking profiles of 10°, 20°, and 30° are shown in FIG. 3, respectively. The horizontal coordinate CDP in the figure represents the lateral coordinate of the seismic data, which represents a set of points collected along the horizontal direction of the ground, and the vertical coordinate represents the time of receiving the seismic wave, which further reflects the longitudinal depth of the underground. The black line in the figure represents the position of the well. Figure 9A 、 Figure 9B 、 Figure 9C Various characteristic waveforms of the seismic wave can be fed back, further reflecting the lithology and rock formation of the underground.

[0099] In this step, the wavelets of the VTI medium shear wave angle-dependent stacking profiles of different angles are extracted respectively to obtain the VTI medium shear wave seismic wavelet convolution matrix of different angles. In some embodiments of the present application, the wavelets extracted from the VTI medium shear wave angle-dependent stacking profiles.

[0100] Step 402, according to the VTI medium shear wave inversion initial model, the shear wave incident angle of the seismic shear wave data, and using the VTI medium shear wave reflection coefficient improvement approximation equation, calculate the VTI medium shear wave reflection coefficient of different shear wave incident angles:

[0101]

[0102] wherein,

[0103]

[0104]

[0105] wherein, θ k is the kth shear wave incident angle, (Z S ) i is calculated according to the VTI medium shear wave inversion initial modelk the i-th shear wave impedance of the VTI medium, (Z S ) i and (Z S ) i+1 respectively represent the i-th shear wave impedance of the reflection interface calculated according to the initial model of the VTI medium shear wave inversion; V SH90 ≈V S0 ·e γ , V S0 is the vertical shear wave velocity, and γ is the shear wave anisotropy parameter; (V SH90 ) i and (V SH90 ) i+1 respectively represent the i-th horizontal shear wave velocity of the reflection interface calculated according to the initial model of the VTI medium shear wave inversion.

[0106] Specifically, on the single interface of the adjacent two layers of VTI medium underground, the improved approximate formula of the shear wave reflection coefficient is represented by the following formula:

[0107]

[0108] where θ is the incident angle of the SH wave; Z S = ρ·V S0 is the shear wave impedance; ρ is the density; V S0 represents the vertical shear wave velocity, and γ is the shear wave anisotropy parameter; Δ and - respectively represent the difference and average calculation of the elastic parameters of the two adjacent media above and below the interface.

[0109] In order to facilitate the inversion to directly obtain the model parameters instead of the difference format of the model parameters, the two terms in formula (4) are written as:

[0110]

[0111] Substituting formula (6) into formula (8) obtains:

[0112]

[0113] V S0 e γ in the above formula is approximately equal to the horizontal SH wave phase velocity V S0 e γ ≈V S0 (1+γ) = V SH90 , and therefore formula (8) is further rewritten as:

[0114]

[0115] According to the derivation, the improved approximate formula of the shear wave reflection coefficient can be obtained:

[0116]

[0117] Step 403, using the product of the VTI medium shear wave reflection coefficient and the multi-angle wavelet convolution matrix, to determine the synthetic data. In some embodiments of the present specification, the synthetic data is the seismic record converted by manual synthesis according to the logging data and the seismic profile data. The synthetic data is the result of the convolution of the seismic wavelet and the reflection coefficient. According to the seismic wavelet determined in the above steps and the VTI medium shear wave reflection coefficient formula, the synthetic data can be determined.

[0118] In the present specification, the synthetic data is represented by G(m). Wherein, G represents a linear forward operator constructed according to the improved approximation formula of the VTI medium shear wave reflection coefficient, which contains the influence of the incident angle and the wavelet. It can be represented as

[0119] G=WFD (11)

[0120] Wherein, W is the wavelet convolution matrix extracted from the pre-stack seismic shear wave data at different angles; F is the Fréchet matrix; D is the difference operator matrix.

[0121]

[0122] The difference matrix is:

[0123]

[0124]

[0125] G(m)=WR, wherein W is the multi-angle wavelet convolution matrix determined in step 401, and R is the VTI medium shear wave reflection coefficient corresponding to different incident angles determined in step 402. The product of the multi-angle wavelet convolution matrix and the VTI medium shear wave reflection coefficient corresponding to different incident angles is obtained. The synthetic data corresponding to different incident angles is obtained.

[0126] Figure 5 The flow chart of a method for determining the VTI medium shear wave inversion result according to an embodiment of the present specification is shown, which includes the following steps:

[0127] Step 501, derive the model parameters in the objective function. In this step, by deriving the objective function J(m) with respect to the model parameters m and equaling to 0, the optimal solution of the objective function is obtained, and further the numerical solution of the model can be obtained.

[0128] Step 502, determine the update amount of the model parameters and the data residual of the model training. After determining the optimal solution of the objective function in step 301, the update amount of the model parameters Δm=m-m0 can be further obtained as

[0129] Δm=(G T G+μI)-1 G T Δd (15)

[0130] where Δd = d - G(m0) represents the data residual, and I represents an identity matrix. The model parameter vector: shear impedance and horizontal shear velocity can be solved by an iterative inversion method:

[0131] m n+1 = m n + Δm (16)

[0132] where n represents the iteration number (m0= m prior )

[0133] Step 503, when the data residual is less than a preset threshold or reaches a maximum iteration number, determining the VTI medium shear wave inversion result. When the data parameter Δd is less than a preset threshold, or the objective function reaches a maximum iteration number, determining the model parameter in the current objective function, and further determining the VTI medium shear wave inversion result, including the inverted shear impedance inversion profile and the horizontal shear velocity inversion profile, as shown in FIGS. Figure 12A and Figure 12B respectively.

[0134] Figure 6 A method flow chart for determining VTI medium shear wave anisotropy parameters is shown in FIG.

[0135] Step 601, obtaining shear impedance logging data and vertical shear velocity logging data from real-time logging data. This step is similar to step 301, and this step obtains shear impedance logging data and vertical shear velocity logging data in real-time logging data.

[0136] Step 602, determining the rock physics relationship between shear impedance logging data and vertical shear velocity by regression analysis on the shear impedance logging data and the vertical shear velocity logging data. In this step, it is assumed that there is a linear relationship between the shear impedance logging data and the vertical shear velocity logging data, and the linear relationship is represented as follows:

[0137] V S0 = a1Z S +a2, where V S0 is the vertical shear velocity logging data, Z S is the shear impedance logging data, and a1 and a2 are coefficients to be fitted.

[0138] The fitting results of the coefficients a1 and a2 obtained by linear regression analysis and minimum mean square prediction error are 0.3341 and 0.3163, respectively. Thus, the rock physics relationship between the shear impedance and the vertical shear velocity is approximately: V S0= 0.3341Z S + 0.3163.

[0139] Step 603, according to the rock physics relationship of the shear wave impedance inversion result, determine the vertical shear wave velocity estimate. In this step, according to the shear wave impedance inversion result in the VTI medium shear wave inversion result, according to the rock physics relationship of V S0 = 0.3341Z S + 0.3163, the vertical shear wave velocity estimate V s0_est .

[0140] Step 604, using the following formula, according to the vertical shear wave velocity estimate, horizontal shear wave velocity inversion result, determine the shear wave anisotropy parameter:

[0141] Wherein, γ is anisotropy parameter, V S0_est is the vertical shear wave velocity estimate, V SH90 is the horizontal shear wave velocity inversion result. According to the horizontal shear wave velocity inversion result, according to the rock physics characteristics of the vertical shear wave velocity estimate, the shear wave anisotropy parameter can be determined.

[0142] As Figure 7 The structure of the VTI medium shear wave anisotropy parameter estimation device based on seismic shear wave inversion is shown in the figure, and the basic structure of the VTI medium shear wave anisotropy parameter estimation device based on seismic shear wave inversion is described in the figure. The functional units and modules in the figure can be realized by software, or can be realized by general chip or special chip based on seismic shear wave inversion. The device specifically comprises:

[0143] Data acquisition unit 701, for acquiring seismic shear wave data, logging data;

[0144] Data determination unit 702, for determining VTI medium shear wave inversion initial model according to the seismic shear wave data and the shear wave anisotropy parameter well data;

[0145] Initial model determination unit 703, for determining VTI medium shear wave inversion initial model according to the shear wave anisotropy parameter well data;

[0146] Synthetic data determination unit 704, for determining synthetic data according to the VTI medium shear wave inversion initial model and the VTI medium shear wave reflection coefficient improved approximation equation;

[0147] Objective function determination unit 705, for determining objective function according to the seismic shear wave data, the synthetic data and the VTI medium shear wave inversion initial model;

[0148] The VTI medium S-wave inversion result determination unit 706 is configured to update parameters in the VTI medium S-wave inversion initial model by using the target function, and determine a VTI medium S-wave inversion result.

[0149] The VTI medium S-wave anisotropy parameter determination unit 707 is configured to determine a VTI medium S-wave anisotropy parameter according to the VTI medium S-wave inversion result.

[0150] The scheme establishes an initial model according to seismic S-wave data and logging data, inverts to obtain S-wave impedance and horizontal S-wave velocity, obtains the relationship between S-wave impedance and vertical S-wave velocity according to logging data, and finally estimates S-wave anisotropy parameters from the horizontal S-wave velocity and the vertical S-wave velocity, thereby effectively realizing seismic S-wave inversion for anisotropic media.

[0151] As an embodiment of the present disclosure, reference can also be made to FIG. 1. Figure 8 FIG. 2 shows a specific structural schematic diagram of a VTI medium S-wave anisotropy parameter estimation method and device based on seismic S-wave inversion according to the embodiment of the present disclosure.

[0152] As an embodiment of the present disclosure, the data determination unit 702 further includes a well-seismic calibration module 7021 configured to match logging data in the depth domain with seismic S-wave data in the time domain.

[0153] The elastic tensor well data determination module 7022 is configured to determine elastic tensor well data.

[0154] As an embodiment of the present disclosure, the synthetic data determination unit 704 further includes:

[0155] The VTI medium S-wave reflection coefficient improved approximation equation determination module 7041 is configured to determine a VTI medium S-wave reflection coefficient improved approximation equation.

[0156] Figure 9A , Figure 9B and Figure 9C respectively represent 10°, 20°, and 30° stack profile schematic diagrams. The horizontal coordinate CDP in the figure represents the horizontal coordinate of seismic data, representing a point set collected along the horizontal direction of the ground, the vertical coordinate represents the time of receiving seismic waves, further reflecting the longitudinal depth of the underground, and the black line in the figure represents the position of the well.

[0157] Figure 10 FIG. 4 shows a schematic diagram of an initial vertical S-wave velocity, an initial density, and an initial S-wave anisotropy parameter according to the embodiment of the present disclosure.

[0158] Figure 11AFig. 1 shows a schematic diagram of an initial S-wave impedance profile according to an embodiment of the present application. The horizontal axis CDP represents the lateral coordinate of the S-wave impedance, representing a set of S-wave impedance along the horizontal direction of the ground surface, and the vertical axis represents time. The black line in the figure represents the position of the well.

[0159] Figure 11B Fig. 2 shows a schematic diagram of an initial horizontal S-wave velocity model according to an embodiment of the present application. The horizontal axis CDP represents the lateral coordinate of the horizontal S-wave velocity, representing a set of horizontal S-wave velocity along the horizontal direction of the ground surface, and the vertical axis represents time. The black line in the figure represents the position of the well.

[0160] Figure 12A Fig. 3 shows a schematic diagram of a S-wave impedance inversion profile according to an embodiment of the present application. The horizontal axis CDP represents the lateral coordinate of the S-wave impedance inversion result, representing a set of S-wave impedance inversion result along the horizontal direction of the ground surface, and the vertical axis represents time. The black line in the figure represents the position of the well.

[0161] Figure 12B Fig. 4 shows a schematic diagram of a horizontal S-wave velocity inversion profile according to an embodiment of the present application. The horizontal axis CDP represents the lateral coordinate of the horizontal S-wave velocity inversion result, representing a set of horizontal S-wave velocity inversion result along the horizontal direction of the ground surface, and the vertical axis represents time. The black line in the figure represents the position of the well.

[0162] Figure 13 Fig. 5 shows a schematic diagram of a vertical S-wave velocity inversion profile and an anisotropy parameter inversion profile according to an embodiment of the present application. The black solid line in the figure represents the actual well data, and the gray solid line represents the S-wave inversion result of the VTI medium.

[0163] As Figure 14As shown, a computer device is provided for the VTI medium anisotropy parameter estimation method based on shear wave inversion of the embodiments of the present application. The computer device 1402 can include one or more processors 1404, such as one or more central processing units (CPUs), each of which can implement one or more hardware threads. The computer device 1402 can also include any memory 1406 for storing any kind of information, such as code, settings, data, etc. Without limitation, for example, the memory 1406 can include any one or combination of: any type of RAM, any type of ROM, a flash memory device, a hard disk, an optical disk, etc. More generally, any memory can use any technology for storing information. Further, any memory can provide volatile or non-volatile retention of information. Further, any memory can represent a fixed or removable component of the computer device 1402. In one case, the computer device 1402 can perform any operation of the associated instructions when executed by the processor 1404 stored in any memory or combination of memories. The computer device 1402 also includes one or more drive mechanisms 1408 for interacting with any memory, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0164] The computer device 1402 can also include an input / output module 1410 (I / O) for receiving various inputs (via input devices 1412) and for providing various outputs (via output devices 1414). One particular output mechanism can include a presentation device 1416 and an associated graphical user interface (GUI) 1418. In other embodiments, the input / output module 1410 (I / O), the input devices 1412, and the output devices 1414 can also not be included, just as a computer device in a network. The computer device 1402 can also include one or more network interfaces 1420 for exchanging data with other devices via one or more communication links 1422. One or more communication buses 1424 couple the above-described components together.

[0165] The communication links 1422 can be implemented in any manner, such as through a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication links 1422 can include any combination of hardwired links, wireless links, routers, gateway functionality, name servers, etc., governed by any protocol or combination of protocols.

[0166] Corresponding to the method in Figures 1-6 The embodiments of the present application also provide a computer readable storage medium, which has stored thereon a computer program, and the computer program is executed by a processor to perform the steps of the above method.

[0167] The embodiments herein also provide a computer program product comprising instructions which, when executed by a processor, cause the processor to carry out the method as shown in Figures 1-6

[0168] It should be understood that the size of the serial number of the processes described above in the various embodiments herein does not mean the order of execution, and the execution order of the processes should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments herein.

[0169] It should also be understood that in the embodiments herein, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships. For example, A and / or B can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are in an "or" relationship.

[0170] Those skilled in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized in electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in the above description in general terms. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A person 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 paper.

[0171] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0172] In several embodiments provided herein, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displays or discussed can be indirect coupling or communication connection through some interfaces, devices or units, and can also be electrical, mechanical or other forms of connection.

[0173] ​The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e. may be located in one place, or may be distributed on multiple network units. Part or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0174] In addition, each functional unit in each embodiment herein can be integrated in one processing unit, or each unit can be physically present alone, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0175] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, the technical solutions herein, essentially or the part of the prior art that contributes to the technical solutions, or all or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment herein. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various program code storage media.

[0176] The principles and implementation manners of the present application are described in the specific embodiments herein, and the above embodiment descriptions are only used to help understand the methods and core ideas thereof; meanwhile, for those skilled in the art, according to the ideas herein, the specific implementation manners and application ranges will have changes, and the above description of the present application should not be understood as a limitation.

Claims

1. A VTI medium shear wave anisotropy parameter estimation method based on shear wave inversion, characterized in that, The method comprises: acquiring seismic shear wave data and well logging data; determining shear wave anisotropy parameter well data according to the well logging data, which comprises: determining a sampling point with shale content exceeding a preset threshold in the well logging data as a VTI medium layer; calculating elastic tensor well data of each sampling point in the VTI medium layer; determining equivalent VTI medium elastic tensor well data of each sampling point according to the elastic tensor well data of each sampling point by using a Backus formula; and calculating shear wave anisotropy parameter well data according to the following formula: where γ is the shear anisotropy parameter well data, respectively, are two numerically different independent parameters of the equivalent VTI medium stiffness matrix. determining a VTI medium shear wave inversion initial model according to the seismic shear wave data and the shear wave anisotropy parameter well data, which comprises: calculating the VTI medium shear wave inversion initial model according to an initial vertical shear wave velocity, an initial density and the initial shear wave anisotropy parameter well data by using the following formula: wherein, is the initial shear wave impedance, is the initial horizontal shear wave velocity, p prior is the initial density, is the initial vertical shear wave velocity, γ prior is the initial shear wave anisotropy parameter, and is the initial shear wave anisotropy parameter, and determining synthetic data according to the VTI medium shear wave inversion initial model and a VTI medium shear wave reflection coefficient improved approximation equation; determining a target function according to the seismic shear wave data, the synthetic data and the VTI medium shear wave inversion initial model; updating parameters in the VTI medium shear wave inversion initial model by using the target function to determine a VTI medium shear wave inversion result; determining VTI medium shear wave anisotropy parameters according to the VTI medium shear wave inversion result.

2. The VTI medium shear anisotropy parameter estimation method based on shear wave inversion according to claim 1, characterized in that, Determining a VTI medium shear wave inversion initial model according to the seismic shear wave data and the shear wave anisotropy parameter well data comprises: converting the seismic shear wave data into angle domain seismic shear wave data to determine a VTI medium shear wave angle division stacking profile; calibrating the VTI medium shear wave angle division stacking profile and the well logging data to convert the well logging data into time domain well logging data; acquiring a vertical shear wave velocity, a density and shear wave anisotropy parameter well data in the time domain well logging data, and performing data smoothing processing and layer extrapolation to obtain an initial vertical shear wave velocity, an initial density and an initial shear wave anisotropy parameter well data.

3. The VTI medium S-wave anisotropy parameter estimation method based on S-wave inversion according to claim 2, characterized in that, Determining synthetic data according to the VTI medium shear wave inversion initial model and a VTI medium shear wave reflection coefficient improved approximation equation comprises: extracting different angle seismic wavelets from the seismic shear wave data to construct a multi-angle wavelet convolution matrix; calculating VTI medium shear wave reflection coefficients of different shear wave incidence angles by using the VTI medium shear wave reflection coefficient improved approximation equation according to the VTI medium shear wave inversion initial model and shear wave incidence angles of the seismic shear wave data: wherein θ is the shear wave incidence angle, (Z S ) i is the shear wave impedance of the i-th reflection interface calculated according to the initial model of VTI medium shear wave inversion, (Z S ) i+1 is the shear wave impedance of the i+1-th reflection interface, (V SH90 ) i is the horizontal shear wave velocity of the i-th reflection interface calculated according to the initial model of VTI medium shear wave inversion, (V SH90 ) i+1 is the horizontal shear wave velocity of the i+1-th reflection interface, V SH90 ≈V S0 ·e γ , V S0 is the vertical shear wave velocity, and γ is the shear wave anisotropy parameter; determining synthetic data by using a product of the VTI medium shear wave reflection coefficients and the multi-angle wavelet convolution matrix.

4. The VTI medium S-wave anisotropy parameter estimation method based on S-wave inversion according to claim 3, characterized in that, The method comprises determining the target function by using the following formula: J(m) = [G(m) - d] + μ(m - m T ) [G(m) - d] + μ(m - m prior ) T (m - m prior ), where J(m) is the objective function, G(m) is the synthetic data, d is the seismic data composed of M different angle seismic gathers, μ is the regularization coefficient, m = [ln(Z S ), ln(V SH90 )] T is the model parameter vector, Z S is the S-wave impedance, V SH90 is the horizontal S-wave velocity inversion result; m prior is the prior model.

5. The VTI medium S-wave anisotropy parameter estimation method based on S-wave inversion according to claim 4, characterized in that, Updating parameters in the VTI medium shear wave inversion initial model by using the target function comprises: deriving model parameters in the target function; determining an update amount of the model parameters and a data residual of model training; determining a VTI medium shear wave inversion result when the data residual is less than a preset threshold or reaches a maximum iteration number.

6. The VTI medium S-wave anisotropy parameter estimation method based on S-wave inversion according to claim 5, characterized in that, The method comprises: Obtaining shear wave impedance logging data and vertical shear wave velocity logging data from real-time logging data; Determining a rock physics relationship between the shear wave impedance logging data and the vertical shear wave velocity by regression analysis on the shear wave impedance logging data and the vertical shear wave velocity logging data; Determining a vertical shear wave velocity estimation value according to the rock physics relationship and the shear wave impedance inversion result in the VTI medium shear wave inversion result; Determining VTI medium shear wave anisotropy parameters according to the vertical shear wave velocity estimation value and the horizontal shear wave velocity inversion result by using the following formula: where γ is an anisotropy parameter, is the vertical shear wave velocity estimate, V SH90 is the horizontal shear wave velocity inversion result.

7. A device for estimating a VTI medium shear anisotropy parameter based on shear wave inversion, characterized in that, The device comprises: A data acquisition unit configured to acquire seismic shear wave data and logging data; A data determination unit configured to determine shear wave anisotropy parameter well data according to the logging data, which comprises: determining sampling points with shale content exceeding a preset threshold in the logging data as VTI medium layers; calculating elastic tensor well data of each sampling point in the VTI medium layers; determining equivalent VTI medium elastic tensor well data of each sampling point according to the elastic tensor well data of each sampling point by using the Backus formula; and calculating shear wave anisotropy parameter well data according to the following formula: where γ is the shear anisotropy parameter well data, respectively, are two numerically different independent parameters of the equivalent VTI medium stiffness matrix; An initial model determination unit configured to determine a VTI medium shear wave inversion initial model according to the seismic shear wave data and the shear wave anisotropy parameter well data, which comprises: calculating the VTI medium shear wave inversion initial model according to an initial vertical shear wave velocity, an initial density and initial shear wave anisotropy parameter well data by using the following formula: wherein, is the initial shear wave impedance, is the initial horizontal shear wave velocity, p prior is the initial density, is the initial vertical shear wave velocity, γ prior is the initial shear wave anisotropy parameter, and well data; A synthetic data determination unit configured to determine synthetic data according to the VTI medium shear wave inversion initial model and a VTI medium shear wave reflection coefficient improved approximation equation; A target function determination unit configured to determine a target function according to the seismic shear wave data, the synthetic data and the VTI medium shear wave inversion initial model; A VTI medium shear wave inversion result determination unit configured to update parameters in the VTI medium shear wave inversion initial model by using the target function to determine a VTI medium shear wave inversion result; A VTI medium shear wave anisotropy parameter determination unit configured to determine VTI medium shear wave anisotropy parameters according to the VTI medium shear wave inversion result.

8. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the method in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the method in any one of claims 1-6.

Images