Seismic inversion method and system based on horizontal uniaxial stress in VTI medium

Abstract

The present disclosure provides a horizontal uniaxial stress seismic inversion method based on VTI medium, relates to the technical field of seismic reservoir identification, and comprises the following steps: constructing an effective stiffness tensor of VTI medium under the action of horizontal uniaxial stress; deducing a PP wave reflection coefficient equation of VTI medium under the action of horizontal uniaxial stress; estimating two crack weakness parameters of a stress-free VTI background medium and two anisotropy parameters induced by horizontal uniaxial stress based on an AVOA inversion method of azimuthal Fourier coefficients. The amplitude-migration and azimuth inversion (AVOA) method based on azimuthal Fourier coefficients is applied to actual data, and it is proved that the stress-induced anisotropy model is suitable for VTI medium reservoir prediction with the action of horizontal uniaxial stress.

Description

Technical Field

[0001] This disclosure relates to the field of seismic reservoir identification technology, specifically to a method and system for seismic inversion based on horizontal uniaxial stress-induced anisotropy in VTI media. Background Technology

[0002] The statements in this section are merely background information relating to this disclosure and do not necessarily constitute prior art.

[0003] Atomic elasticity (TI) media with a vertical axis of symmetry within rock strata is called volatile TI media. Studying seismic inversion methods under various conditions in VTI media plays a crucial role. In research on the influence of stress on changes in rock elastic properties, two main approaches exist: linear elasticity theory and nonlinear elasticity theory. Compared to traditional linear elasticity theory, nonlinear acoustoelasticity theory can introduce third-order elastic constants to describe the effect of stress on changes in rock elastic properties.

[0004] Previous studies have often neglected stress-induced anisotropy when considering the sources of seismic anisotropy. However, since geostress is ubiquitous underground, this neglect often leads to inaccuracies in anisotropy calculations. Summary of the Invention

[0005] To address the aforementioned issues, this disclosure proposes a seismic inversion method and system based on horizontal uniaxial stress in VTI media. A stress-induced weak anisotropy model is established to describe the dependence of the effective elastic stiffness tensor and PP wave reflection coefficient on horizontal uniaxial stress in VTI media. The reflection coefficient is expressed as a form of Fourier coefficient, and the amplitude-migration and azimuth inversion (AVOA) method based on azimuth Fourier coefficients is applied to actual data.

[0006] According to some embodiments, the present disclosure adopts the following technical solutions:

[0007] Seismic inversion methods based on horizontal uniaxial stress in VTI media include:

[0008] Construct the effective stiffness tensor of VTI medium under horizontal uniaxial stress;

[0009] The equation for the reflection coefficient of PP waves in VTI media under horizontal uniaxial stress is derived using parameters calculated from the corresponding effective stiffness tensor.

[0010] Synthetic seismic records were obtained using the PP wave reflection coefficient equation. Based on the AVOA inversion method using azimuth Fourier coefficients, two fracture weakness parameters and two anisotropic parameters induced by horizontal uniaxial stress in the stress-free VTI background medium were estimated.

[0011] According to some embodiments, the present disclosure adopts the following technical solutions:

[0012] A seismic inversion system based on horizontal uniaxial stress in VTI media includes:

[0013] The equation construction module is used to construct the effective stiffness tensor of VTI medium under horizontal uniaxial stress; the PP wave reflection coefficient equation of VTI medium under horizontal uniaxial stress is derived using the parameters calculated from the corresponding effective stiffness tensor.

[0014] The inversion module is used to obtain the synthetic seismic record using the PP wave reflection coefficient equation. Based on the azimuth Fourier coefficient AVOA inversion method, it estimates two fracture weakness parameters and two anisotropic parameters induced by horizontal uniaxial stress in the stress-free VTI background medium.

[0015] According to some embodiments, the present disclosure adopts the following technical solutions:

[0016] A non-transitory computer-readable storage medium is provided for storing computer instructions, which, when executed by a processor, implement the aforementioned seismic inversion method based on horizontal uniaxial stress in VTI medium.

[0017] According to some embodiments, the present disclosure adopts the following technical solutions:

[0018] An electronic device includes a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory to enable the electronic device to implement the aforementioned seismic inversion method based on horizontal uniaxial stress in VTI medium.

[0019] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0020] This disclosure establishes a stress-induced weak anisotropy model based on nonlinear acoustoelastic theory. This model describes the dependence of the effective elastic stiffness tensor and PP wave reflection coefficient on horizontal uniaxial stress in VTI media. The model primarily addresses the anisotropy problem caused by horizontal stress, describing the azimuth reflection characteristics of PP waves with orthogonal anisotropy induced by horizontal uniaxial stress in VTI media. The reflection coefficient is then expressed as a form of azimuth Fourier coefficients. The amplitude-migration and azimuth inversion (AVOA) method based on azimuth Fourier coefficients is applied to real data, demonstrating that the proposed stress-induced anisotropy model is applicable to the prediction of VTI reservoirs with horizontal uniaxial stress. Attached Figure Description

[0021] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure.

[0022] Figure 1 A schematic diagram illustrating the sensitivity analysis of the zero-order Fourier coefficients to the model parameters;

[0023] in, Figure 1 (a) represents the longitudinal wave reflection coefficient R. M ;

[0024] Figure 1 (b) represents the transverse wave reflection coefficient R. μ ;

[0025] Figure 1 (c) represents the density reflectance coefficient R ρ ;

[0026] Figure 1 (d) represents the crack weakness parameter.

[0027] Figure 1 (e) represents the crack weakness parameter.

[0028] Figure 1 (f) represents the anisotropy parameter induced by uniaxial stress.

[0029] Figure 1 (g) represents the anisotropy parameter induced by uniaxial stress.

[0030] Figure 2 A schematic diagram illustrating the sensitivity analysis of the second-order Fourier coefficients to the model parameters;

[0031] in, Figure 2 (a) represents the anisotropy parameter induced by uniaxial stress.

[0032] Figure 2 (b) represents the anisotropy parameter induced by uniaxial stress.

[0033] Figure 3 A schematic diagram illustrating the sensitivity analysis of the fourth-order Fourier coefficients to the model parameters;

[0034] in, Figure 3 (a) represents the anisotropy parameter induced by uniaxial stress.

[0035] Figure 3 (b) represents the anisotropy parameter induced by uniaxial stress.

[0036] Figure 4 This represents noise-free synthesized seismic record angle gathers for different azimuth angles.

[0037] in, Figure 4 (a) indicates an azimuth angle of 22.5°;

[0038] Figure 4 (b) indicates an azimuth angle of 67.5°;

[0039] Figure 4 (c) indicates an azimuth angle of 112.5°;

[0040] Figure 4 (d) indicates an azimuth angle of 157.5°;

[0041] Figure 5 This represents the graphs of different model parameters obtained using the zero-order Fourier coefficients of noise-free data.

[0042] in, Figure 5 (a) represents the longitudinal wave modulus;

[0043] Figure 5 (b) represents the transverse wave modulus;

[0044] Figure 5 (c) represents density;

[0045] Figure 6 This represents the crack weakness and seismic wave anisotropy parameters of the VTI medium model obtained under noise-free conditions.

[0046] in, Figure 6 (a) represents the normal crack weakness under stress-free VTI background;

[0047] Figure 6 (b) represents the tangential crack weakness in the stress-free VTI background;

[0048] Figure 6 (c) indicates the applied horizontal uniaxial stress T 11 Related horizontal uniaxial stress-induced longitudinal wave anisotropy parameters;

[0049] Figure 6 (d) represents the applied horizontal uniaxial stress T 11 Related horizontal uniaxial stress-induced transverse wave anisotropy parameters;

[0050] Figure 7 Angle gather images of synthetic seismic records with SNR=5 at different azimuth angles;

[0051] in, Figure 7 (a) indicates an azimuth angle of 22.5°;

[0052] Figure 7 (b) indicates an azimuth angle of 67.5°;

[0053] Figure 7 (c) indicates an azimuth angle of 112.5°;

[0054] Figure 7 (d) indicates an azimuth angle of 157.5°;

[0055] Figure 8 Images representing different model parameters obtained from the zero-order Fourier coefficients of noise data with SNR=5;

[0056] in, Figure 8 (a) represents the longitudinal wave modulus;

[0057] Figure 8 (b) represents the transverse wave modulus;

[0058] Figure 8 (c) represents density;

[0059] Figure 9 This represents the crack weakness and seismic wave anisotropy parameters of the VTI medium model obtained under the SNR=5 noise condition;

[0060] in, Figure 9 (a) represents the normal crack weakness under stress-free VTI background;

[0061] Figure 9 (b) represents the tangential crack weakness in the stress-free VTI background;

[0062] Figure 9 (c) indicates the applied horizontal uniaxial stress T 11 Related horizontal uniaxial stress-induced longitudinal wave anisotropy parameters;

[0063] Figure 9 (d) represents the applied horizontal uniaxial stress T 11 Related horizontal uniaxial stress-induced transverse wave anisotropy parameters;

[0064] Figure 10 Seismic data image representing a 22.5° azimuth angle;

[0065] in, Figure 10 (a) indicates near offset data;

[0066] Figure 10 (b) indicates the mid-offset data;

[0067] Figure 10 (c) indicates far offset data;

[0068] Figure 11 Seismic data image representing a 67.5° azimuth angle;

[0069] in, Figure 11(a) indicates near offset data;

[0070] Figure 11 (b) indicates the mid-offset data;

[0071] Figure 11 (c) indicates far offset data;

[0072] Figure 12 Seismic data image representing a 112.5° azimuth angle;

[0073] in, Figure 12 (a) indicates near offset data;

[0074] Figure 12 (b) indicates the mid-offset data;

[0075] Figure 12 (c) indicates far offset data;

[0076] Figure 13 Seismic data image representing a 157.5° azimuth angle;

[0077] in, Figure 13 (a) indicates near offset data;

[0078] Figure 13 (b) indicates the mid-offset data;

[0079] Figure 13 (c) indicates far offset data;

[0080] Figure 14 This represents the images of different model parameters obtained using the zero-order Fourier coefficients based on a real dataset;

[0081] in, Figure 14 (a) represents the longitudinal wave modulus;

[0082] Figure 14 (b) represents the transverse wave modulus;

[0083] Figure 14 (c) represents density;

[0084] Figure 15 This image represents the crack weakness inversion result based on a real dataset using the zero-order Fourier coefficients.

[0085] in, Figure 15 (a) represents the result of stress-free VTI background normal crack weakness inversion;

[0086] Figure 15 (b) represents the inversion result of tangential crack weakness in the stress-free VTI background;

[0087] Figure 16This represents the image obtained by inverting the seismic wave anisotropy parameters using second-order Fourier coefficients based on a real dataset.

[0088] in, Figure 16 (a) represents the applied horizontal uniaxial stress T. 11 Related horizontal uniaxial stress-induced longitudinal wave anisotropy parameters;

[0089] Figure 16 (b) represents the applied horizontal uniaxial stress T. 11 Related horizontal uniaxial stress-induced transverse wave anisotropy parameters. Detailed implementation method:

[0090] The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

[0091] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0092] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0093] Example 1

[0094] One embodiment of this disclosure provides a seismic inversion method based on horizontal uniaxial stress in VTI media, including:

[0095] Step 1: Construct the effective stiffness tensor of the VTI medium under horizontal uniaxial stress;

[0096] Step 2: Derive the equation for the reflection coefficient of PP waves in VTI medium under horizontal uniaxial stress using the parameters calculated from the corresponding effective stiffness tensor.

[0097] Step 3: Using the PP wave reflection coefficient equation, the synthetic seismic record is obtained. Based on the azimuth Fourier coefficient AVOA inversion method, the two fracture weakness parameters of the stress-free VTI background medium and the two anisotropic parameters induced by horizontal uniaxial stress are estimated.

[0098] Specifically, the effective elastic stiffness matrix of the VTI medium under horizontal uniaxial stress is described using nonlinear elasticity theory, and the effective stiffness tensor of the VTI medium affected by horizontal uniaxial stress is constructed.

[0099] Under the assumptions of weak anisotropy and low stress, the background crack parameters of stress-free VTI media are... and and the stress induced by horizontal uniaxial stress and Much smaller than the stress-free elastic parameter, the effective stiffness tensor of a VTI medium under horizontal uniaxial stress can be expressed as:

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109] Where M and μ represent the longitudinal modulus and shear modulus of the unstressed rock, respectively; λ = M - 2μ represents the first Lamé constant of the unstressed rock; g = μ / M; and (Referred to as normal weakness and shear weakness in the unstressed VTI background, respectively) represent two dimensionless quantities that describe the VTI characteristics of unstressed rocks.

[0110] in and It is related to the application of horizontal uniaxial stress T 11 The two relevant uniaxial stress-induced anisotropy parameters are derived from

[0111]

[0112]

[0113] Where M and μ represent the longitudinal modulus and shear modulus of the non-stressed rock, respectively;

[0114] Where C 155 and C 456 These represent two third-order elastic constants that control the anisotropy of P-waves and S-waves caused by horizontal uniaxial stress.

[0115] As one embodiment, the process of deriving the PP wave reflection coefficient equation of VTI medium under horizontal uniaxial stress includes: VTI medium under horizontal uniaxial stress exhibits orthotropic anisotropy, and the PP wave reflection coefficient is expressed as the sum of two crack parameters of the stress-free VTI background medium and two anisotropic parameters induced by horizontal uniaxial stress.

[0116] Generally, VTI media under horizontal uniaxial stress exhibit orthogonal (ORT) anisotropy. AVOA inversion of VTI media under horizontal uniaxial stress has been extensively studied. This disclosure directly expresses the PP wave reflection coefficient as the sum of the two crack weaknesses ( ) in the stress-free VTI background medium. and ) and two horizontal uniaxial stress-induced anisotropy parameters ( and The sum of:

[0117]

[0118] in The orientation-independent reflection coefficient generated by the stress-free VTI background medium. The azimuth reflection coefficient related to the observed azimuth angle caused by horizontal uniaxial stress; θ and These are the earthquake incident angle and the observation azimuth angle r0, respectively.

[0119] The reflection coefficient of PP waves related to horizontal uniaxial stress in VTI media is linearized, and the VTI media induced by horizontal uniaxial stress is represented as a scatterer embedded in a non-stress background. The linearized reflection coefficient of PP waves is expressed as a function of the scattering function using Born integral and fixed phase method.

[0120] Specifically, to linearize the PP wave reflection coefficient related to horizontal uniaxial stress in a VTI medium, the VTI medium induced by horizontal uniaxial stress is represented as a scatterer embedded in a stress-free background. This disclosure uses Born integrals and the fixed-phase method to express the linearized PP wave reflection coefficient as a function of the scattering function S(r0):

[0121]

[0122] S(r0)=Δρξ+ΔC ij η ij (14)

[0123] Where position r0 represents the horizontal interface separating two anisotropic media, ρ represents the background medium density, and Δρ represents the density perturbation; ξ and η ij With respect to the slowness and polarization vector of the incident and scattered waves; ΔC ij Perturbation representing the elastic stiffness tensor:

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133] In the derivation process, based on the assumptions of weak anisotropy and small stress, the following was neglected: And the higher-order terms that contain it.

[0134] Substituting the expression into the equation, we get...

[0135]

[0136] in,

[0137]

[0138] a μ (θ)=-4gsin 2 θ, (26)

[0139]

[0140]

[0141]

[0142]

[0143]

[0144] Where R M =ΔM / 2M, R μ =Δμ / 2μ and R ρ =Δρ / 2ρ represents the reflectivity of the longitudinal wave modulus, the transverse wave modulus, and the density, respectively; and

[0145] To address the characteristics of VTI media under horizontal uniaxial stress, azimuth Fourier coefficients are used to invert stress-related anisotropic parameters.

[0146] The linearized PP wave reflection coefficient can be expressed in the form of azimuth Fourier coefficients.

[0147]

[0148]

[0149]

[0150]

[0151] in,

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158] Figures 1 to 3 Sensitivity analyses of the zeroth, second, and fourth order Fourier coefficients are presented respectively. The results show that the zeroth order Fourier coefficient significantly affects the model parameter R. M R μ R ρ , and More sensitive, the second-order Fourier coefficients affect the model parameters and More sensitive, while the fourth-order Fourier coefficients affect the model parameters. and The sensitivity is low. Therefore, the zero-order Fourier coefficients are used to evaluate the model parameters R. M R μ R ρ , and Inversion is performed, using second-order Fourier coefficients to evaluate the model parameters. and Perform the inversion.

[0159] Wherein, the longitudinal wave reflection coefficient is R M The transverse wave reflection coefficient is R. μ The density reflectance is R. ρThe crack weakness parameter is: Crack weakness parameter is The anisotropy parameters induced by uniaxial stress are

[0160] To verify the azimuth Fourier coefficient AVOA inversion method for VTI media considering horizontal uniaxial stress, this disclosure first estimates the crack weakness points of stress-free VTI media using a synthesized azimuth angle dataset. and ) and uniaxial stress-induced P-wave and S-wave anisotropy parameters ( and ).

[0161] Figure 4 This is a noise-free synthetic azimuth seismic dataset with four azimuth angles of 22.5°, 67.5°, 112.5°, and 157.5°. Figure 5 and Figure 6 The estimated model parameters include P-wave and S-wave moduli, density, two crack weaknesses in the stress-free VTI background medium, and two uniaxial stress-induced anisotropy parameters, where P-wave and S-wave moduli, density, and crack weaknesses are estimated by zero-order Fourier coefficients, and P-wave and S-wave anisotropy parameters are estimated by second-order Fourier coefficients.

[0162] Subsequently, noise synthesis data were used to further verify the inversion method proposed in this invention. Figure 7 This is synthetic noise data with a signal-to-noise ratio of 5. Figure 8 and Figure 9 The results show the inversion of the model parameters. The study found that the density inversion accuracy was poor due to seismic noise, while other model parameters were largely consistent with the actual synthetic data. The inversion results of the noisy data demonstrate that the proposed AVOA inversion method for horizontal uniaxial stress VTI media based on azimuth Fourier coefficients is stable and effective.

[0163] To further demonstrate the applicability of the method, a real dataset obtained from the Sichuan Basin in China was used. When the target layer is a gas-bearing reservoir, the VTI anisotropy mainly comes from the weak bias characteristics of quartz grains on the bedding plane and the fine microcracks caused by grain contact.

[0164] This disclosure uses azimuth seismic data to perform the proposed inversion method. The actual data includes four azimuth angles (22.5°, 67.5°, 112.5°, and 157.5°) and three incident angles (15°, 22°, and 29°). Before inversion, the data is processed to ensure the true amplitude response and eliminate noise. Figure 10 , 11 12 and 13 are the azimuth seismic data used in this invention. The target reservoir is located at approximately 2.38s in trace 2479.

[0165] Figure 14 a, 14b, and 14c are the P-wave and S-wave moduli and densities estimated using the zero-order Fourier coefficients, respectively. However, the estimated isotropic parameters do not show obvious outliers at the target reservoir. Therefore, they cannot be used to characterize gas-bearing reservoirs.

[0166] Figure 15 a, 15b, and 15c represent the positive and tangential fracture weakness in the stress-free VTI background estimated using the zero-order Fourier coefficients. The inversion results show that the fracture weakness in the stress-free VTI background is relatively high at the target reservoir, but the anomaly is not significant. This is because the target reservoir is in a high-pressure environment, and the source of seismic anisotropy or azimuthal seismic response characteristics in this region mainly originates from stress-induced anisotropy, rather than inherent or fracture-induced anisotropy.

[0167] Figure 16 a, 16b, and 16c are the estimated values ​​of the P-wave and S-wave anisotropy parameters induced by uniaxial stress, respectively. It can be observed that, compared with the fracture weakness estimated under a stress-free VTI background, the horizontal uniaxial stress-induced anisotropy parameters inverted using the second-order Fourier coefficients show high anomalies at the target reservoir, because they represent stress-induced seismic anisotropy.

[0168] Calculation examples demonstrate that this inversion method can provide an alternative approach for characterizing VTI media that take into account the effects of horizontal uniaxial stress.

[0169] Example 2

[0170] One embodiment of this disclosure provides a seismic inversion system based on horizontal uniaxial stress in VTI media, comprising:

[0171] The equation construction module is used to construct the effective stiffness tensor of VTI medium under horizontal uniaxial stress; the PP wave reflection coefficient equation of VTI medium under horizontal uniaxial stress is derived using the parameters calculated from the corresponding effective stiffness tensor.

[0172] The inversion module is used to obtain the synthetic seismic record using the PP wave reflection coefficient equation. Based on the azimuth Fourier coefficient AVOA inversion method, it estimates two fracture weakness parameters and two anisotropic parameters induced by horizontal uniaxial stress in the stress-free VTI background medium.

[0173] Example 3

[0174] One embodiment of this disclosure provides a non-transitory computer-readable storage medium for storing computer instructions, which, when executed by a processor, implement the steps of the described method for seismic inversion based on horizontal uniaxial stress in VTI media.

[0175] Example 4

[0176] One embodiment of this disclosure provides an electronic device, including a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory to cause the electronic device to perform the steps of implementing the seismic inversion method based on horizontal uniaxial stress in VTI medium.

[0177] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0178] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0179] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. A seismic inversion method based on horizontal uniaxial stress in VTI media, characterized in that, include: Construct the effective stiffness tensor of VTI medium under horizontal uniaxial stress; The equation for the PP wave reflection coefficient of VTI medium under horizontal uniaxial stress is derived using parameters calculated from the corresponding effective stiffness tensor. This includes: VTI medium under horizontal uniaxial stress exhibits orthogonal anisotropy, and the PP wave reflection coefficient is expressed as the sum of two crack parameters of the stress-free VTI background medium and two anisotropic parameters induced by horizontal uniaxial stress. Synthetic seismic records were obtained using the PP wave reflection coefficient equation. Based on the AVOA inversion method using azimuth Fourier coefficients, two fracture weakness parameters and two anisotropic parameters induced by horizontal uniaxial stress in the stress-free VTI background medium were estimated.

2. The seismic inversion method based on horizontal uniaxial stress in VTI medium as described in claim 1, characterized in that, The method for constructing the effective stiffness tensor of VTI medium under horizontal uniaxial stress is to use nonlinear elasticity theory to describe the effective elastic stiffness matrix of VTI medium under horizontal uniaxial stress, and then construct the effective stiffness tensor of VTI medium affected by horizontal uniaxial stress.

3. The seismic inversion method based on horizontal uniaxial stress in VTI medium as described in claim 1, characterized in that, The reflection coefficient of PP waves related to horizontal uniaxial stress in VTI media is linearized, and the VTI media induced by horizontal uniaxial stress is represented as a scatterer embedded in a non-stress background. The linearized reflection coefficient of PP waves is expressed as a function of the scattering function using Born integral and fixed phase method.

4. The seismic inversion method based on horizontal uniaxial stress in VTI medium as described in claim 1, characterized in that, The AVOA inversion of the azimuth Fourier coefficients is based on the characteristics of VTI medium under horizontal uniaxial stress, and the azimuth Fourier coefficients are used to invert the stress-related anisotropic parameters.

5. The seismic inversion method based on horizontal uniaxial stress in VTI medium as described in claim 4, characterized in that, The linearized PP wave reflection coefficient is expressed in the form of azimuth Fourier coefficients.

6. The seismic inversion method based on horizontal uniaxial stress in VTI medium as described in claim 5, characterized in that, The model parameters were inverted using the zero-order Fourier coefficients and the second-order Fourier coefficients, respectively.

7. A seismic inversion system based on horizontal uniaxial stress in VTI medium, characterized in that, include: The equation building module is used to construct the effective stiffness tensor of a VTI medium under horizontal uniaxial stress. The equation for the PP wave reflection coefficient of VTI medium under horizontal uniaxial stress is derived using parameters calculated from the corresponding effective stiffness tensor. This includes: VTI medium under horizontal uniaxial stress exhibits orthogonal anisotropy, and the PP wave reflection coefficient is expressed as the sum of two crack parameters of the stress-free VTI background medium and two anisotropic parameters induced by horizontal uniaxial stress. The inversion module is used to obtain the synthetic seismic record using the PP wave reflection coefficient equation. Based on the azimuth Fourier coefficient AVOA inversion method, it estimates two fracture weakness parameters and two anisotropic parameters induced by horizontal uniaxial stress in the stress-free VTI background medium.

8. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium is used to store computer instructions, which, when executed by a processor, implement the seismic inversion method based on horizontal uniaxial stress in VTI medium as described in any one of claims 1-6.

9. An electronic device, characterized in that, include: The device includes a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory to enable the electronic device to perform the seismic inversion method based on horizontal uniaxial stress in VTI medium as described in any one of claims 1-6.

Images