VTI medium forward modeling method and device, electronic equipment and storage medium

Abstract

The invention provides a VTI medium forward modeling method and device, electronic equipment and a storage medium, and the method comprises the steps: constructing a VTI thin layer, and obtaining the vertical slowness of a longitudinal wave and the vertical slowness of a converted shear wave according to a single-interface reflection coefficient analytical solution of the VTI thin layer; constructing a thin interbed medium clamping a VTI thin layer, and obtaining a total reflection coefficient of a slowness-frequency domain of the thin interbed medium through an anisotropic fast reflectivity method; converting the total reflection coefficient of the slowness-frequency domain into a total reflection coefficient of an angle-time domain; and performing convolution operation on the seismic wavelets and the total reflection coefficient of the angle-time domain to obtain a forward simulation seismic record. According to the method, for a thin reservoir and a reservoir with developed low-angle cracks, a reflectivity method formula suitable for anisotropic media is obtained, and the calculation speed is increased; and full wave field simulation of the reservoir can be realized, and forward simulation seismic records are closer to actual data in amplitude and AVO curve trends.

Description

Technical Field

[0001] The present application relates to the field of oil and gas geophysical exploration, and specifically to a VTI medium forward simulation method, device, electronic equipment and storage medium. Background Art

[0002] Transverse isotropy with a vertical axis of symmetry (VTI) caused by the combination of horizontal fractures, inherent mineral orientation, and horizontal thin layers is one of the most common forms of anisotropy. The above-mentioned tight sandstone thin reservoir with horizontal fractures can be equivalent to a thin interlayer medium sandwiched by VTI medium, and the VTI medium will have a significant impact on the amplitude of seismic data and the amplitude versus offset / angle (AVO / AVA). It is necessary to perform forward simulation of VTI medium, explore the intrinsic response mechanism and time-frequency variation law of this type of reservoir, and perform seismic prediction of this type of tight sandstone reservoir. Reflection coefficient is the basis of forward simulation. The general idea of ​​studying forward simulation of VTI medium at home and abroad is: first propose a seismic reflection coefficient calculation method suitable for isotropic layered media, then expand the method to anisotropic media, and finally study the AVO response law for specific geological models. The following are the commonly used reflection coefficient calculation methods:

[0003] (1) Study on reflection coefficient based on single interface theory

[0004] This theory regards the thin interlayer as a set of layered media, calculates the reflection coefficient of each interface separately, and then uses the convolution model to simulate the AVO seismic record, and extracts the extreme amplitude of the composite wave as the AVO response curve. For isotropic media, most seismic theories related to AVO are based on the Zoeppritz equation and its various approximate formulas. These formulas only reflect the change of the reflection coefficient with the elastic parameters and anisotropic parameters on both sides of the interface, and do not consider the seismic wave propagation effects such as geometric diffusion, absorption attenuation, transmission loss and multiple waves. When the above equations are used to study the AVO response of thin-layer media or thin interlayer media sandwiched by VTI media, it is usually hoped that the actual seismic data can be processed as consisting of only one reflection. However, when thin layers exist, the internal structural characteristics of the reservoir are diverse, the combination relationships are many, and the time-frequency response characteristics are complex, which will form complex conversion waves. Especially in the case of thin interlayers, the complex conversion waves have a greater impact on the actual record than the multiple waves, which also contain important reservoir information and should not be ignored. Therefore, using the single interface theory to calculate the AVO response curve of thin-layer media or thin interlayer media sandwiched by VTI media will produce large errors. The formula based on the single-interface hypothesis theory is no longer applicable to explore the intrinsic response mechanism and time-frequency variation law of this type of reservoir, which restricts the research and development of seismic prediction of this type of tight sandstone reservoir.

[0005] (2) Study on the reflection coefficient of isotropic layered media based on propagation matrix theory

[0006] The idea is to regard the thin interlayer as a set of isotropic layered media, establish the energy transfer relationship of each single layer in the thin interlayer by means of a propagation matrix, and thus establish a matrix equation for calculating the reflection and transmission coefficients of the thin interlayer, and use it to analyze the AVO response of the thin interlayer. This type of method goes beyond the simple assumptions based on the ray tracing forward modeling method, uses the analytical solution of the wave equation, and has very accurate simulation results. In addition, this method can simulate the complex wave field response within the layer, including reflection waves, transmission waves, conversion waves, and multiple waves, and can fully reflect the information of the wave field of the thin interlayer. It is the method that is closest to the actual situation. However, due to the complexity of the formula, this method is difficult to apply to the inversion of thin interlayer parameters like the Zoeppritz equation and its approximate formula, so this method is currently more used in forward simulation analysis.

[0007] (3) Using propagation matrix theory to study the reflection coefficient of anisotropic layered media

[0008] For layered media containing anisotropic media, the anisotropic reflection and transmission coefficients of each single interface can be calculated first, and then connected in series by the modified propagation matrix to obtain the final reflection coefficient formula. This scheme can accurately calculate the full wavefield characteristics of anisotropic layered media. The theory of studying anisotropic layered media based on propagation matrix theory does not restrict the thickness of the layered media, so the theory can be applied to anisotropic layered media containing thin layers. Due to the complexity of the above formula, fast calculations similar to those in isotropic media have not been achieved. For thin interlayer reservoir exploration, the goal is to identify several thin layers containing oil and gas in the background of thin interlayers, but it is very difficult to directly apply the above method to inversion to identify thin layers containing oil and gas. Therefore, it is urgent to develop a method for fast calculation of reflection coefficients of anisotropic layered media suitable for thin interlayers to improve the speed of forward simulation and subsequent inversion calculations. Summary of the invention

[0009] In view of this, the present application provides a VTI medium forward simulation method, device, electronic device and storage medium, so as to solve the technical problems in the prior art that the calculation formula of the reflection coefficient of anisotropic layered media is complex, and the forward simulation speed and subsequent inversion calculation speed are slow.

[0010] In a first aspect, the present application provides a VTI medium forward modeling method, comprising:

[0011] Construct a VTI thin layer, and obtain the vertical slowness of the longitudinal wave and the vertical slowness of the converted shear wave according to the analytical solution of the single interface reflection coefficient of the VTI thin layer;

[0012] A thin interlayer medium sandwiched with a single thin layer of VTI is constructed, and a total reflection coefficient of the thin interlayer medium in a slowness-frequency domain is obtained by an anisotropic fast reflectivity method;

[0013] Transforming the total reflection coefficient in the slowness-frequency domain into the total reflection coefficient in the angle-time domain;

[0014] The seismic wavelet is convolved with the total reflection coefficient in the angle-time domain to obtain the forward modeling seismic record.

[0015] Furthermore, the vertical slowness of the longitudinal wave is:

[0016]

[0017] The vertical slowness of the converted shear wave is:

[0018]

[0019] Among them, the horizontal slow speed p is:

[0020]

[0021] v P0 is the longitudinal wave velocity in the vertical direction, v S0 is the converted shear wave velocity in the vertical direction, and ε and δ are the Thomsen anisotropy parameters.

[0022] Further, the anisotropic rapid reflectivity method comprises:

[0023] Define a vector ν containing 6 elements, the vector ν is:

[0024] v0=[Δ -R PS Δ -R SS Δ R PP Δ R SP Δ detRΔ] T ,

[0025] Where Δ is the proportionality coefficient, R PS is the total reflection coefficient of the converted shear wave, R SS is the total reflection coefficient of shear waves, R PP is the total reflection coefficient of the longitudinal wave, R SP is the total reflection coefficient of the converted longitudinal wave, det R is the determinant of the reflection coefficient;

[0026] ν0 is calculated by recursive method:

[0027] v0=Q0Q1…Q n …Q N-1 v N ,n∈[0,N-1],

[0028] Among them, Q is the propagation matrix of the formation, Q n is the propagation matrix of layer n, ν N is the initial item;

[0029] The propagation matrix of the formation is:

[0030] Q=EF,

[0031] Among them, E is the layer crossing matrix and F is the interface matrix;

[0032] The initial term ν N for:

[0033] v N =[1 0 0 0 0 0] T ,

[0034] The vector v is expanded to the frequency domain divided into M parts to obtain a complex vector containing 6×M elements

[0035] Expanding the propagation matrix of the stratum into a frequency domain divided into M parts;

[0036] Solve the complex vector by recursion The total reflection coefficient of the thin interlayer medium in the slowness-frequency domain is obtained.

[0037] Furthermore, the layer traversal matrix is:

[0038]

[0039] Where h is the layer thickness of the stratum, q P is the vertical slowness of the longitudinal wave, q S is the vertical slowness of the converted shear wave.

[0040] Further, the step of extending the propagation matrix of the stratum to a frequency domain divided into M parts includes:

[0041] The interface matrix F remains unchanged, and the layer crossing matrix E is expanded to the frequency domain divided into M parts using a recursive algorithm to obtain the expanded layer crossing matrix

[0042] Furthermore, the use of a recursive algorithm to expand the layer traversal matrix E to a frequency domain divided into M parts includes:

[0043] Set the growth factor:

[0044] G = diag[1 / s + ,1,1 / s - ,s - ,1,s + ]

[0045] in,

[0046]

[0047] Where h is the layer thickness of the stratum, q P is the vertical slowness of the longitudinal wave, q S is the vertical slowness of the converted shear wave;

[0048] Set the initial value E 1,2,···，6 = 1.0, the expanded layer traversal matrix is ​​obtained recursively through the growth factor

[0049]

[0050] m is the number of copies in the frequency domain.

[0051] Furthermore, the total reflection coefficient of the thin interlayer medium in the slowness-frequency domain is:

[0052]

[0053]

[0054] Among them, R PP (p,ω) is the total reflection coefficient of the longitudinal wave in the slowness-frequency domain of the thin interlayer medium, R PS (p,ω) is the total reflection coefficient of the shear wave converted from the slowness to the frequency domain in the thin interlayer medium, p is the horizontal slowness, ω is the frequency, ν0(1), ν0(2), ν0(4) are the first, second and fourth elements of the vector ν0, respectively.

[0055] In a second aspect, the present application provides a VTI medium forward simulation device, comprising:

[0056] The vertical slowness acquisition module constructs a VTI thin layer and obtains the vertical slowness of the longitudinal wave and the vertical slowness of the converted shear wave based on the analytical solution of the single interface reflection coefficient of the VTI thin layer;

[0057] A total reflection coefficient acquisition module in the slowness-frequency domain is used to construct a thin interlayer medium sandwiched between VTI thin layers, and obtain the total reflection coefficient in the slowness-frequency domain of the thin interlayer medium by anisotropic fast reflectivity method;

[0058] A transformation module, transforming the total reflection coefficient in the slowness-frequency domain into the total reflection coefficient in the angle-time domain;

[0059] The forward modeling module performs convolution operation on the seismic wavelet and the total reflection coefficient in the angle-time domain to obtain the forward modeling seismic record.

[0060] In a third aspect, the present application provides an electronic device, including:

[0061] processor;

[0062] Memory;

[0063] And a computer program, wherein the computer program is stored in the memory, and the computer program includes instructions, and when the instructions are executed by the processor, the electronic device executes any one of the methods described in the first aspect.

[0064] In a fourth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute any one of the methods described in the first aspect.

[0065] This application is aimed at thin reservoirs and reservoirs with low-angle fractures. The anisotropic parameters are calculated based on the pseudo-anisotropy theory, and then the single-interface reflection coefficient calculation method and the recursive algorithm in the total reflection coefficient are improved to obtain the reflectivity method formula applicable to anisotropic media. The reflectivity method formula is reorganized to achieve vectorization and improve the calculation speed. The method of this application has the following specific advantages: (1) There is no limit on the reservoir thickness and it can be applied to thin reservoirs; (2) It is applicable to low-angle fracture reservoirs; (3) The calculation speed is fast; (4) It can realize the full wave field simulation of the reservoir, including conversion waves and multiple waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0067] Figure 1 A schematic diagram of a flow chart of a VTI medium forward simulation method provided in an embodiment of the present application;

[0068] Figure 2 A comparison chart of the forward modeling earthquake record and the actual earthquake record provided in the embodiment of the present application;

[0069] Figure 3 Provided in the embodiments of this application Figure 2 AVO curve at T1 in the earthquake record;

[0070] Figure 4 A structural block diagram of a VTI medium forward simulation device provided in an embodiment of the present application;

[0071] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0072] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0073] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0074] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0075] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0076] See also Figure 1 , is a flow chart of a VTI medium forward simulation method provided in an embodiment of the present application, and the method mainly includes the following steps.

[0077] S101: construct a VTI thin layer, and obtain the vertical slowness of the longitudinal wave and the vertical slowness of the converted shear wave according to the analytical solution of the single interface reflection coefficient of the VTI thin layer.

[0078] When the stress and displacement on both sides of the interface are continuous, a set of linear equations for reflection and transmission coefficients are obtained. This set of equations is expressed in matrix form:

[0079] SR=B,R=S -1 B (1)

[0080] By solving this matrix, we can get the accurate reflection and transmission coefficients. The matrix S, vector R and vector B are expressed as follows. Set c ij *=c ij / ρ, vector R is the reflection and transmission coefficient vector:

[0081]

[0082]

[0083] in, is the reflection coefficient of the downgoing longitudinal wave, is the reflection coefficient of the downlink converted shear wave, is the reflection coefficient of the downlink converted longitudinal wave, is the reflection coefficient of the downgoing shear wave, is the reflection coefficient of the upward longitudinal wave, is the reflection coefficient of the upgoing converted shear wave, is the reflection coefficient of the upgoing converted longitudinal wave, is the reflection coefficient of the upgoing shear wave; is the transmission coefficient of the downward longitudinal wave, is the transmission coefficient of the downlink converted shear wave, is the transmission coefficient of the downlink converted longitudinal wave, is the transmission coefficient of the downward shear wave, is the transmission coefficient of the upward longitudinal wave, is the transmission coefficient of the upgoing converted shear wave, is the transmission coefficient of the upgoing converted longitudinal wave, is the transmission coefficient of the upward shear wave.

[0084] R D , T D , T U , R U The specific result can be written as:

[0085]

[0086]

[0087]

[0088]

[0089] The matrix S is:

[0090]

[0091] Vector B can be calculated as follows:

[0092]

[0093] in,

[0094]

[0095] Wherein, n = 1, 2. 1 represents the medium on the upper layer of the interface, and 2 represents the medium on the lower layer of the interface;

[0096]

[0097]

[0098]

[0099]

[0100]

[0101] Among them, v P0 is the longitudinal wave velocity in the vertical direction, v S0 is the converted shear wave velocity in the vertical direction, ε is the Thomsen anisotropy parameter, q α is the vertical slowness of the longitudinal wave, qβ In order to convert the vertical slowness of the shear wave and facilitate the derivation of the anisotropic fast reflectivity method, the vertical slowness of the longitudinal wave is recorded as q P , the vertical slowness of the converted shear wave is denoted as q S , then q P =q α ,q S =q β ,q α and q β The specific expression is as follows:

[0102]

[0103]

[0104] in:

[0105]

[0106]

[0107]

[0108] Among them, c ij is the stiffness tensor, ρ is the density, and p is the horizontal slowness.

[0109] Replace the vertical slowness symbol q in Equation 12 and Equation 13 α and q β Replace with q P and q S , and expressed in terms of Thomsen anisotropy parameters, can be written as follows:

[0110]

[0111]

[0112] Among them, the horizontal slow speed p is:

[0113]

[0114] v P0 is the longitudinal wave velocity in the vertical direction, v S0 is the converted shear wave velocity in the vertical direction, and ε and δ are the Thomsen anisotropy parameters.

[0115] S102: construct a thin interlayer medium sandwiching a single thin layer of VTI, and obtain a total reflection coefficient of the thin interlayer medium in a slowness-frequency domain by an anisotropic fast reflectivity method.

[0116] Among them, the anisotropic fast reflectivity method includes:

[0117] Define a vector ν containing 6 elements, the vector ν is:

[0118] v0=[Δ -R PS Δ -R SS Δ R PP Δ R SP Δ detRΔ] T , (20)

[0119] Where Δ is the proportionality coefficient, R PS is the total reflection coefficient of the converted shear wave, R SS is the total reflection coefficient of shear waves, R PP is the total reflection coefficient of the longitudinal wave, R SP is the total reflection coefficient of the converted longitudinal wave, detR is the reflection coefficient determinant;

[0120] ν0 is calculated by recursive method:

[0121] v0=Q0Q1…Q n …Q N-1 v N ,n∈[0,N-1], (21)

[0122] Among them, Q is the propagation matrix of the formation, Q n is the propagation matrix of layer n, ν N is the initial item;

[0123] The propagation matrix of the formation is:

[0124] Q=EF, (22)

[0125] Among them, E is the layer crossing matrix and F is the interface matrix.

[0126] Then the propagation matrix Q of layer n is n for:

[0127] Q n =E n F n (twenty three)

[0128] Among them, E n is the layer crossing matrix of layer n, F n is the interface matrix of formation n.

[0129] The layer crossing matrix E of layer n n, describes the phase shift of a plane wave as it propagates in layer n. The general anisotropic recursion relation implicitly assumes that for each wave type, the vertical slownesses for upward and downward propagation are not equal. In the general problem of wave propagation in anisotropic media, the recursive format involves a 3×3 matrix. For VTI media and isotropic media, the vertical slownesses for upward and downward propagation are just the negatives of each other, and the recursive format involves a 2×2 matrix. Therefore, the specific form of the layer crossing matrix for VTI media is as follows:

[0130]

[0131] Where h is the layer thickness of the stratum, q P is the vertical slowness of the longitudinal wave, q S is the vertical slowness of the shear wave.

[0132] Then the layer crossing matrix E of layer n is n The specific form is as follows:

[0133]

[0134] Among them, h n is the layer thickness of layer n, is the vertical slowness of the P-wave in layer n, is the vertical slowness of the shear wave in layer n.

[0135] F of stratum n n It can be specifically written as:

[0136]

[0137] Among them, T -1 n and T n+1 are the upward interface propagation matrix and the downward interface propagation matrix, T n is a 6×6 matrix whose elements are derived from the Dunkin matrix.

[0138] The initial term ν N for:

[0139] v N =[1 0 0 0 0 0] T , (27)

[0140] When the initial term ν is determined N After obtaining the propagation matrix Q of the stratum, the vector ν and the propagation matrix Q of the stratum can be expanded to the frequency domain divided into M parts, and then ν0 can be calculated through a recursive algorithm.

[0141] First, the vector ν is expanded to the frequency domain divided into M parts to obtain a complex vector containing 6×M elements

[0142]

[0143] The initial value of the matrix is m is the frequency domain copy number, m=1, 2,..., M, and the rest of the values ​​are all set to 0.

[0144] Secondly, the propagation matrix of the stratum is expanded to the frequency domain which is divided into M parts.

[0145] Because the interface matrix F is independent of frequency, the interface matrix F remains unchanged. It is only necessary to use a recursive algorithm to expand the layer crossing matrix E to the frequency domain divided into M parts to obtain the expanded layer crossing matrix

[0146] Set the growth factor:

[0147] G = diag[1 / s + ,1,1 / s - ,s - ,1,s + ] (29)

[0148] in,

[0149]

[0150] Where h is the layer thickness of the stratum, q P is the vertical slowness of the longitudinal wave, q S is the vertical slowness of the shear wave.

[0151] Set the initial value E 1,2,···，6 = 1.0, the expanded layer traversal matrix is ​​obtained recursively through the growth factor

[0152]

[0153] m is the number of copies in the frequency domain.

[0154] After the vector ν and the propagation matrix Q of the stratum are expanded to the frequency domain divided into M parts, ν0 is calculated by a recursive algorithm.

[0155] Finally, the total reflection coefficient of the thin interlayer medium in the slowness-frequency domain is obtained as:

[0156]

[0157]

[0158] Among them, R PP (p,ω) is the total reflection coefficient of the longitudinal wave in the slowness-frequency domain of the thin interlayer medium, RPS (p,ω) is the total reflection coefficient of the shear wave converted from the slowness to the frequency domain in the thin interlayer medium, p is the horizontal slowness, ω is the frequency, ν0(1), ν0(2), ν0(4) are the first, second and fourth elements of the vector ν0, respectively.

[0159] S103: transforming the total reflection coefficient in the slowness-frequency domain into a total reflection coefficient in the time-angle domain.

[0160] First, convert the slowness into an angle. The incident angle of each angle gather is fixed. For horizontal strata, the slowness corresponding to the incident angle of each layer can be obtained by Snell's law:

[0161]

[0162] Among them, p n is the horizontal slowness of the nth layer, θ is the incident angle, ν pn represents the longitudinal wave velocity of the nth layer, and n represents the nth layer.

[0163] Given a target angle, the angle is converted to slowness using formula 34, that is, the total reflection coefficient R(p,ω) in the slowness-frequency domain is converted to the total reflection coefficient R(θ,ω) in the angle-frequency domain.

[0164] Secondly, convert the frequency domain to the time domain. Perform an inverse Fourier transform on the reflection coefficient and finally obtain the total reflection coefficient in the time-angle domain (τ-θ):

[0165]

[0166] Where τ is the intercept time, θ is the incident angle, and R(θ,ω) is the total reflection coefficient in the angle-frequency domain.

[0167] S104: Perform convolution operation on the seismic wavelet and the total reflection coefficient in the angle-time domain to obtain a forward modeling seismic record.

[0168] After obtaining the total reflection coefficient in the time-angle domain, the seismic record is obtained by convolution of the reflection coefficient and the wavelet:

[0169] Φ=W*R, (36)

[0170] Among them, Φ is the simulated seismic record, W is the wavelet of the corresponding incident angle, and assuming that its sampling rate is l, its specific form can be written as:

[0171]

[0172] Taking the actual data of Xinchang area in western Sichuan as an example, the target reservoir has relatively developed low-angle fractures, and the overall structure is sandstone interbedded deposition, the thickness of the single-layer sand body is thin, and the burial depth is more than 4000-5000m. The above actual data are simulated based on the fast anisotropic reflectivity method (FARM) and the precise Zoeppritz equation of this application to simulate the pre-stack seismic records, and the forward simulation seismic records based on the Zoeppritz equation and the forward simulation seismic records based on FARM are obtained, and compared with the actual data, such as Figure 2 To compare the differences between the simulated data and the actual data in more detail, we extracted Figure 2 The AVO curve at T1 is as follows: Figure 3 As shown. Among them, the scattered points represent the amplitude data points, and the solid curve represents the scattered point regression curve. The top solid curve represents the forward simulation earthquake record based on FARM, the middle solid curve represents the actual earthquake record, and the top solid curve represents the forward simulation earthquake record based on Zoeppritz. Figure 3 It can be seen that compared with the forward modeling seismic records based on the Zoeppritz equation, the forward modeling seismic records based on FARM are closer to the actual data in terms of amplitude and AVO curve trend.

[0173] This application aims at thin reservoirs and reservoirs with low-angle fractures. It calculates anisotropic parameters based on pseudo-anisotropy theory, and then improves the single-interface reflection coefficient calculation method and the recursive algorithm in the total reflection coefficient to obtain a reflectivity method formula suitable for anisotropic media. The reflectivity method formula has been reorganized to achieve vectorization and improve the calculation speed. The method of this application has no restrictions on reservoir thickness and can be applied to thin reservoirs and reservoirs with low-angle fractures. It can realize full wavefield simulation of the reservoir, including conversion waves and multiple waves. Its forward simulation seismic records are closer to actual data in terms of amplitude and AVO curve trend.

[0174] Corresponding to the above-mentioned embodiment, the present application also provides a VTI medium forward simulation device.

[0175] See also Figure 4 , is a structural block diagram of a VTI medium forward simulation device provided in an embodiment of the present application, and the device mainly includes the following modules.

[0176] A vertical slowness acquisition module 401 constructs a VTI thin layer and obtains the vertical slowness of the longitudinal wave and the vertical slowness of the converted shear wave according to the analytical solution of the single interface reflection coefficient of the VTI thin layer;

[0177] A total reflection coefficient acquisition module 402 in the slowness-frequency domain constructs a thin interlayer medium sandwiched by a VTI thin layer, and obtains the total reflection coefficient in the slowness-frequency domain of the thin interlayer medium by an anisotropic fast reflectivity method;

[0178] A transformation module 403 transforms the total reflection coefficient in the slowness-frequency domain into a total reflection coefficient in the angle-time domain;

[0179] The forward modeling module 404 performs a convolution operation on the seismic wavelet and the total reflection coefficient in the angle-time domain to obtain a forward modeling seismic record.

[0180] It should be pointed out that the specific contents involved in the embodiments of the present application can be found in the description of the above method embodiments, and for the sake of brevity, they will not be repeated here.

[0181] Corresponding to the above embodiment, an embodiment of the present application further provides an electronic device.

[0182] See also Figure 5 , is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 5 As shown, the electronic device 500 may include: a processor 501, a memory 502 and a communication unit 503. These components communicate via one or more buses. Those skilled in the art will appreciate that the electronic device structure shown in the figure does not limit the embodiments of the present application, and it may be a bus structure or a star structure, and may include more or fewer components than shown in the figure, or combine certain components, or arrange components differently.

[0183] The communication unit 503 is used to establish a communication channel so that the electronic device can communicate with other devices.

[0184] The processor 501 is the control center of the electronic device. It uses various interfaces and lines to connect various parts of the entire electronic device. It runs or executes software programs and / or modules stored in the memory 502, and calls data stored in the memory to perform various functions of the electronic device and / or process data. The processor can be composed of an integrated circuit (IC), for example, it can be composed of a single packaged IC, or it can be composed of multiple packaged ICs with the same or different functions. For example, the processor 501 can include only a central processing unit (CPU). In the embodiment of the present application, the CPU can be a single computing core or multiple computing cores.

[0185] The memory 502 is used to store the execution instructions of the processor 501. The memory 502 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0186] When the execution instructions in the memory 502 are executed by the processor 501 , the electronic device 500 is enabled to execute part or all of the steps in the above method embodiment.

[0187] Corresponding to the above embodiment, the embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium may store a program, wherein when the program is running, the device where the computer-readable storage medium is located may be controlled to perform some or all of the steps in the above method embodiment. In a specific implementation, the computer-readable storage medium may be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM).

[0188] Corresponding to the above-mentioned embodiment, the embodiment of the present application further provides a computer program product, which includes executable instructions. When the executable instructions are executed on a computer, the computer executes some or all of the steps in the above-mentioned method embodiment.

[0189] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0190] Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0191] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0192] In several embodiments provided in the present application, any function can be stored in a computer-readable storage medium if it is implemented in the form of a software functional unit and sold or used as an independent product. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., and other media that can store program codes.

[0193] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A VTI medium forward modeling method, characterized in that: include: Construct a VTI thin layer, and obtain the vertical slowness of the longitudinal wave and the vertical slowness of the converted shear wave according to the analytical solution of the single interface reflection coefficient of the VTI thin layer; A thin interlayer medium sandwiched with a single thin layer of VTI is constructed, and a total reflection coefficient of the thin interlayer medium in a slowness-frequency domain is obtained by an anisotropic fast reflectivity method; Transforming the total reflection coefficient in the slowness-frequency domain into the total reflection coefficient in the angle-time domain; The seismic wavelet is convolved with the total reflection coefficient in the angle-time domain to obtain the forward modeling seismic record.

2. The method according to claim 1, characterized in that The vertical slowness of the longitudinal wave is: The vertical slowness of the converted shear wave is: Among them, the horizontal slow speed p is: v P0 is the longitudinal wave velocity in the vertical direction, v S0 is the converted shear wave velocity in the vertical direction, and ε and δ are the Thomsen anisotropy parameters.

3. The method according to claim 1, characterized in that: The anisotropic rapid reflectivity method comprises: Define a vector ν containing 6 elements, the vector ν is: v0=[Δ -R PS D -R SS D R PP D R SP Δ detRΔ] T , Where Δ is the proportionality coefficient, R PS is the total reflection coefficient of the converted shear wave, R SS is the total reflection coefficient of shear waves, R PP is the total reflection coefficient of the longitudinal wave, R SP is the total reflection coefficient of the converted longitudinal wave, det R is the determinant of the reflection coefficient; ν0 is calculated by recursive method: v0=Q0Q1…Q n …Q N-1 v N ,n∈[0,N-1], Among them, Q is the propagation matrix of the formation, Q n is the propagation matrix of layer n, ν N is the initial item; The propagation matrix of the formation is: Q=EF, Among them, E is the layer crossing matrix and F is the interface matrix; The initial term ν N for: v N ＝[1 0 0 0 0 0] T , The vector v is expanded to the frequency domain divided into M parts to obtain a complex vector containing 6×M elements Expanding the propagation matrix of the stratum into a frequency domain divided into M parts; Solve the complex vector by recursion The total reflection coefficient of the thin interlayer medium in the slowness-frequency domain is obtained.

4. The method according to claim 3, characterized in that: The layer traversal matrix is: Where h is the layer thickness, q P is the vertical slowness of the longitudinal wave, q S is the vertical slowness of the converted shear wave.

5. The method according to claim 3, characterized in that: The step of extending the propagation matrix of the stratum to a frequency domain divided into M parts comprises: The interface matrix F remains unchanged, and the layer crossing matrix E is expanded to the frequency domain divided into M parts using a recursive algorithm to obtain the expanded layer crossing matrix 6. The method according to claim 5, characterized in that The recursive algorithm is used to expand the layer traversal matrix E to the frequency domain divided into M parts, including: Set the growth factor: G=diag[1 / s + ,1,1 / s - ,s - ,1,s + ] in, Where h is the layer thickness, q P is the vertical slowness of the longitudinal wave, q S is the vertical slowness of the converted shear wave; Set the initial value E 1,2,···，6 = 1.0, the expanded layer traversal matrix is ​​obtained recursively through the growth factor m is the number of copies in the frequency domain.

7. The method according to claim 6, characterized in that The total reflection coefficient of the thin interlayer medium in the slowness-frequency domain is: Among them, R PP (p,ω) is the total reflection coefficient of the longitudinal wave in the slowness-frequency domain of the thin interlayer medium, R PS (p,ω) is the total reflection coefficient of the shear wave converted from the slowness to the frequency domain in the thin interlayer medium, p is the horizontal slowness, ω is the frequency, ν0(1), ν0(2), ν0(4) are the first, second and fourth elements of the vector ν0, respectively.

8. A VTI medium forward simulation device, comprising: The vertical slowness acquisition module constructs a VTI thin layer and obtains the vertical slowness of the longitudinal wave and the vertical slowness of the converted shear wave based on the analytical solution of the single interface reflection coefficient of the VTI thin layer; A total reflection coefficient acquisition module in the slowness-frequency domain is used to construct a thin interlayer medium sandwiched between VTI thin layers, and obtain the total reflection coefficient in the slowness-frequency domain of the thin interlayer medium by anisotropic fast reflectivity method; A transformation module, transforming the total reflection coefficient in the slowness-frequency domain into the total reflection coefficient in the angle-time domain; The forward modeling module performs convolution operation on the seismic wavelet and the total reflection coefficient in the angle-time domain to obtain the forward modeling seismic record.

9. An electronic device, characterized in that: include: processor; Memory; And a computer program, wherein the computer program is stored in the memory, and the computer program includes instructions, and when the instructions are executed by the processor, the electronic device executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method according to any one of claims 1 to 7.

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