Inversion method and related equipment for dielectric layer thickness and wave velocity

Abstract

The present application provides a method for inverting the thickness and wave velocity of a dielectric layer and related equipment; the method comprises: using the displacement wave field and stress wave field of the first boundary of the current layer to determine the up-down potential function coefficients of the transverse wave and the longitudinal wave, and determining the displacement wave field at the second boundary; using the up-down potential function coefficients to decompose the displacement wave field at the first boundary into a down-down longitudinal wave displacement wave field, a down-down transverse wave displacement wave field, a down-up longitudinal wave displacement wave field and a down-up transverse wave displacement wave field; using the down-up longitudinal wave displacement wave field or the down-up transverse wave displacement wave field to determine the thickness of the current layer; using the current layer thickness to solve the displacement wave field and the stress wave field at the second boundary and decompose the displacement wave field at the second boundary, thereby determining a first reflectivity using the first up-up longitudinal wave displacement wave field, the first up-up transverse wave displacement wave field and the first up-down longitudinal wave displacement wave field at the second boundary, and determining the wave velocity of the next layer using the first reflectivity.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of waveform inversion, and more particularly to a method for inverting dielectric layer thickness and wave velocity and related equipment. Background Art

[0002] The traditional elastic full waveform inversion method based on the local fitting method faces the problems of local minima and mutual interference of multi-parameter inversion in multi-parameter inversion. At the same time, there is a great dependence on the global initial model during full waveform inversion. The use of a global initial model that deviates greatly from the true model will directly lead to the failure of the traditional elastic full waveform inversion method. Summary of the invention

[0003] In view of this, the purpose of this application is to propose a method and related equipment for inversion of dielectric layer thickness and wave velocity.

[0004] Based on the above purpose, the present application provides an inversion method for medium layer thickness and wave velocity, including:

[0005] Determine a transverse wave and a longitudinal wave into which an incident wave is decomposed based on the incident wave at a first boundary of a current layer of a preset medium, and determine an upward potential function coefficient and a downward potential function coefficient of the transverse wave and the longitudinal wave in the current layer by using a displacement wave field and a stress wave field at the first boundary;

[0006] Decomposing the displacement wavefield at the first boundary into a lower downward P-wave displacement wavefield, a lower downward S-wave displacement wavefield, a lower upward P-wave displacement wavefield and a lower upward S-wave displacement wavefield under the first boundary by using the upward potential function coefficient and the downward potential function coefficient in the current layer;

[0007] Determine the thickness of the current layer between the first boundary and the second boundary by using the first waveform of the lower upgoing longitudinal wave displacement wave field or the first waveform of the lower upgoing shear wave displacement wave field at the time when the first boundary appears, wherein the second boundary of the current layer is the first boundary of the next layer;

[0008] Determine the displacement wave field and stress wave field at the second boundary by using the current layer thickness, and decompose the displacement wave field at the second boundary into an upper downward longitudinal wave displacement wave field, an upper downward shear wave displacement wave field, an upper upward longitudinal wave displacement wave field and an upper upward shear wave displacement wave field at the second boundary;

[0009] The first reflectivity is determined using the first waveform of the upper upward longitudinal wave displacement wave field and the first waveform of the upper upward shear wave displacement wave field, and the wave velocities of the shear wave and the longitudinal wave in the next layer are determined using the first reflectivity.

[0010] The displacement wave field includes a first displacement wave field along a first coordinate axis in a preset coordinate system and a second displacement wave field along a second coordinate axis in the coordinate system, and the stress wave field includes a first stress wave field along the first coordinate axis and a second stress wave field along the second coordinate axis.

[0011] Further, using the displacement wave field and the stress wave field at the first boundary to determine the upward potential function coefficient and the downward potential function coefficient of the shear wave and the longitudinal wave in the current layer, and determining the displacement wave field at the second boundary, comprises:

[0012] Construct the first stiffness matrix and the second stiffness matrix as shown below,

[0013]

[0014]

[0015] Wherein, M represents the first stiffness matrix, N represents the second stiffness matrix, e represents the natural logarithm, x represents the direction of the first coordinate axis, z represents the direction of the second coordinate axis, l x It represents the cosine value of the propagation direction of the longitudinal wave relative to the x-axis, l z Represents the cosine value of the propagation direction of the longitudinal wave relative to the z-axis, m x Represents the cosine value of the propagation direction of the shear wave relative to the x-axis, m z represents the cosine value of the propagation direction of the shear wave relative to the z-axis, k represents the wave number in the horizontal direction, i represents the i-th layer of the medium, j represents the imaginary unit, α represents the velocity of the longitudinal wave, β represents the velocity of the shear wave, and h i represents the thickness of the i-th layer,

[0016]

[0017] The first stiffness matrix is ​​used to construct the relationship between the displacement wave field and the upward potential function coefficient and the downward potential function coefficient in the current layer as shown below, and the second stiffness matrix is ​​used to construct the relationship between the stress wave field and the upward potential function coefficient and the downward potential function coefficient in the current layer as shown below, so as to determine the upward potential function coefficient and the downward potential function coefficient in the current layer, and determine the displacement wave field at the second boundary,

[0018]

[0019] Among them, u i-1 represents the first displacement wave field at the first boundary of the i-1th layer, w i-1 represents the second displacement wave field at the first boundary of the i-1th layer, p i-1 represents the first stress wave field at the first boundary of the i-1th layer, ri-1 represents the second stress wave field at the first boundary of the i-1th layer, represents the coefficient of the upward potential function of the longitudinal wave in the i-th layer, represents the coefficient of the downward potential function of the i-th layer of the longitudinal wave, represents the coefficient of the upward potential function of the i-th layer of the shear wave, represents the coefficient of the downward potential function of the i-th layer of the shear wave, M 1:2,1:4 Represents the elements of the first 4 columns in the first 2 rows of the first stiffness matrix, N 1:2,1:4 Represents the elements of the first 4 columns in the first 2 rows of the second stiffness matrix.

[0020] Further, the displacement wavefield at the first boundary is decomposed into a downward longitudinal displacement wavefield below the first boundary, a downward shear displacement wavefield below, an upward longitudinal displacement wavefield below, and an upward shear displacement wavefield below using the upward potential function coefficient and the downward potential function coefficient in the current layer, including:

[0021] The relationship between the displacement wave field of the first boundary and the upward potential function coefficient and the downward potential function coefficient in the current layer is decomposed to obtain the decomposition formulas of the downward longitudinal wave displacement wave field, downward shear wave displacement wave field, upward longitudinal wave displacement wave field and upward shear wave displacement wave field of the first boundary as shown below:

[0022]

[0023]

[0024] in, represents the unit vector in the direction of the first coordinate axis shown, represents the unit vector in the direction of the second coordinate axis shown, represents the displacement wave field of the upward P-wave below the first boundary of the i-1th layer, represents the downward longitudinal displacement wave field below the first boundary of the i-1th layer, represents the upward shear wave displacement field below the first boundary of the i-1th layer, represents the downward shear wave displacement field below the first boundary of the i-1th layer, M 11 represents the element of the first row and first column of the first stiffness matrix, M 12 represents the element in the first row and second column of the first stiffness matrix, M 13 represents the element in the first row and third column of the first stiffness matrix, M 14 represents the element in the first row and fourth column of the first stiffness matrix, M 21 represents the element of the second row and first column of the first stiffness matrix, M 22 represents the element of the second row and second column of the first stiffness matrix, M 23represents the element in the second row and third column of the first stiffness matrix, M 24 Represents the element in the 2nd row and 4th column of the first stiffness matrix.

[0025] Further, determining the current layer thickness between the first boundary and the second boundary by using the first waveform of the lower upgoing longitudinal wave displacement wave field or the first waveform of the lower upgoing shear wave displacement wave field at the time when the first boundary appears includes:

[0026] Determine a first time difference between the emission time of the first waveform of the downward longitudinal displacement wave field below the first boundary of the current layer and the appearance time of the first waveform of the downward longitudinal displacement wave field, wherein the downward longitudinal displacement wave field is a wave field in which the longitudinal wave generated by the reflection of the first boundary of the next layer or the second boundary of the current layer after the downward longitudinal displacement wave field propagates reaches the lower side of the first boundary of the current layer;

[0027] Determine the current layer thickness using the formula shown below,

[0028]

[0029] Among them, h i represents the thickness of the i-th layer, α i represents the velocity of the longitudinal wave in the i-th layer, t pp represents the first time difference, represents the propagation direction of the longitudinal wave in the i-th layer.

[0030] Further, the current layer thickness between the first boundary and the second boundary is determined by using the first waveform of the lower upgoing longitudinal wave displacement wave field or the first waveform of the lower upgoing shear wave displacement wave field at the time when the first boundary appears, and further includes:

[0031] Determine a second time difference between the emission time of the first waveform of the downward longitudinal displacement wavefield below the first boundary of the current layer and the appearance time of the first waveform of the downward upward shear displacement wavefield, wherein the downward upward shear displacement wavefield is a wavefield in which the shear wave generated by the reflection of the first boundary of the next layer or the second boundary of the current layer after the downward longitudinal displacement wavefield propagates reaches the lower side of the first boundary of the current layer;

[0032] Determine the current layer thickness using the formula shown below,

[0033]

[0034] Among them, β i represents the velocity of the shear wave in the i-th layer, t ps represents the second time difference, represents the propagation direction of the shear wave in the i-th layer.

[0035] Further, the displacement wave field and the stress wave field at the second boundary are determined using the current layer thickness, including:

[0036] Using the current layer thickness, the upward potential function coefficient and the downward potential function coefficient in the current layer, the following formula is constructed to determine the displacement wave field and stress wave field at the second boundary:

[0037]

[0038] Among them, u i represents the first displacement wave field at the second boundary of the i-th layer, w i represents the second displacement wave field at the first boundary of the i-th layer, p i represents the first stress wave field at the second boundary of the i-th layer, r i represents the second stress wave field at the first boundary of the i-th layer, M 3:4,1:4 Represents the elements of the first four columns in the last two rows of the first stiffness matrix, N 3:4,1:4 Represents the elements of the first 4 columns in the last 2 rows of the second stiffness matrix.

[0039] The first reflectivity includes a first longitudinal wave reflectivity determined by an amplitude ratio between a first waveform of an upper downward longitudinal wave displacement wave field and a first waveform of an upper upward longitudinal wave displacement wave field, and a first shear wave reflectivity determined by an amplitude ratio between a first waveform of an upper downward longitudinal wave displacement wave field and a first waveform of an upper upward shear wave displacement wave field;

[0040] Further, using the first reflectivity to determine the wave velocities of the transverse wave and the longitudinal wave in the next layer respectively includes:

[0041] The longitudinal wave velocity and the shear wave velocity of the next layer are determined according to the reflectivity relationship shown below using the first longitudinal wave reflectivity and the first shear wave reflectivity.

[0042]

[0043] Among them, r pp represents the first longitudinal wave reflectivity, r ps represents the first shear wave reflectivity, q represents the ray parameter, and a, b, c, d, D, F and H are all parameters.

[0044] Further, using the first reflectivity to determine the wave velocities of the transverse wave and the longitudinal wave in the next layer respectively, further comprising:

[0045] Construct a relationship between the longitudinal wave velocity and the transverse wave velocity of the next layer and the second reflectivity as shown below, wherein the second reflectivity includes a second longitudinal wave reflectivity and a second transverse wave reflectivity,

[0046]

[0047] Among them, R pp represents the second longitudinal wave reflectivity, R ps represents the second shear wave reflectivity;

[0048] Within the preset wave velocity range, the error between the second longitudinal wave reflectivity and the first longitudinal wave reflectivity is determined. When the sum of the errors between the second shear wave reflectivity and the first shear wave reflectivity is the smallest, the longitudinal wave velocity and shear wave velocity of the corresponding next layer are determined.

[0049] Based on the same inventive concept, the present application also provides a device for inverting dielectric layer thickness and wave velocity, comprising:

[0050] A coefficient determination module, a first decomposition module, a thickness determination module, a second decomposition module and a wave speed determination module;

[0051] The coefficient determination module is configured to determine the transverse wave and the longitudinal wave into which the incident wave is decomposed based on the incident wave at the first boundary of the current layer of the preset medium, and determine the upward potential function coefficient and the downward potential function coefficient of the transverse wave and the longitudinal wave in the current layer by using the displacement wave field and the stress wave field at the first boundary;

[0052] The first decomposition module is configured to decompose the displacement wavefield at the first boundary into a lower downward longitudinal displacement wavefield, a lower downward shear displacement wavefield, a lower upward longitudinal displacement wavefield and a lower upward shear displacement wavefield at the lower side of the first boundary by using the upward potential function coefficient and the downward potential function coefficient in the current layer;

[0053] The thickness determination module is configured to determine the thickness of the current layer between the first boundary and the second boundary by using the first waveform of the lower upgoing longitudinal wave displacement wave field or the first waveform of the lower upgoing shear wave displacement wave field at the time when the first boundary appears, wherein the second boundary of the current layer is the first boundary of the next layer;

[0054] The second decomposition module is configured to determine the displacement wavefield and stress wavefield at the second boundary by using the current layer thickness, and decompose the displacement wavefield at the second boundary into an upper downward longitudinal wave displacement wavefield, an upper downward shear wave displacement wavefield, an upper upward longitudinal wave displacement wavefield and an upper upward shear wave displacement wavefield at the second boundary;

[0055] The wave velocity determination module is configured to determine a first reflectivity using a first waveform of an upper upward longitudinal wave displacement wave field and a first waveform of an upper upward shear wave displacement wave field, and to determine the wave velocities of shear waves and longitudinal waves in the next layer respectively using the first reflectivity.

[0056] Based on the same inventive concept, the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the inversion method for dielectric layer thickness and wave velocity as described in any one of the above items is implemented.

[0057] Based on the same inventive concept, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the inversion method of medium layer thickness and wave velocity as mentioned above.

[0058] Based on the same concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a computer program product, including computer program instructions, which, when executed on a computer, enables the computer to execute the inversion method of dielectric layer thickness and wave velocity as described in any of the above items.

[0059] From the above description, it can be seen that the inversion method and related equipment for medium layer thickness and wave velocity provided by the present application calculate the up-down potential function coefficients in the current layer of the preset medium based on the displacement wave field and stress wave field determined at the first boundary, so as to decompose the displacement wave field using the up-down potential function coefficients, so as to determine the lower down-going longitudinal wave displacement wave field and the lower up-going longitudinal wave displacement wave field on the lower side of the first boundary, based on which, the thickness of the current layer is determined by the time difference between the first waveform of the lower down-going longitudinal wave displacement wave field and the first waveform of the lower up-going longitudinal wave displacement wave field, so as to decompose the displacement wave field at the second boundary of the current layer using the current layer thickness, realize the decomposition and extrapolation of the wave field, and then determine the first reflectivity using the first waveform of the up-going longitudinal wave displacement wave field on the upper side of the second boundary and the first waveform of the upper up-going transverse wave displacement wave field, and then use the first reflectivity to realize the determination of the wave velocity of the next layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0061] Figure 1 A schematic diagram of medium layering and wave fields according to an embodiment of the present application;

[0062] Figure 2 A flow chart of a method for inverting dielectric layer thickness and wave velocity according to an embodiment of the present application;

[0063] Figure 3A schematic diagram of the structure of a device for inverting reflectivity and wave velocity in a medium according to an embodiment of the present application;

[0064] Figure 4 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0065] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0066] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connecting" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0067] As described in the background technology section, the related inversion methods of dielectric layer thickness and wave velocity are still difficult to meet the needs of waveform inversion in practical work.

[0068] In the process of implementing the present application, the applicant discovered that the main problems with the related waveform inversion methods are: the traditional elastic full waveform inversion method based on the local fitting method faces the problems of local minima and mutual interference of multi-parameter inversion in multi-parameter inversion. At the same time, there is a great dependence on the global initial model during full waveform inversion. The use of a global initial model that deviates greatly from the true model will directly lead to the failure of the traditional elastic full waveform inversion method.

[0069] Based on this, one or more embodiments of the present application provide an inversion method for dielectric layer thickness and wave velocity.

[0070] In the embodiments of the present application, underground medium is taken as a specific example of the preset medium, such as Figure 1 As shown, the underground medium is multi-layer, among which z 0 represents the first boundary of the underground medium, z 0 Below is the area of ​​underground medium, z 0 Above is the ground area, z 0 As the first boundary of layer 1, z 1is the second boundary of layer 1, and z 1 It is also the first boundary of the second layer. That is to say, for any current layer, the first boundary is the first boundary of the previous layer, and the second boundary of the current layer is the first boundary of the next layer.

[0071] Furthermore, the underground medium has n layers, z n is the second boundary of the nth layer.

[0072] In this embodiment, Figure 1 Construct a coordinate system in the underground medium in Figure 1 The direction of boundary extension with each layer is the first coordinate axis direction of the coordinate system, and is represented as the x-axis direction. The direction of the arrow running through each layer is the second coordinate axis direction in the coordinate system, and is represented as the z-axis direction. The coordinate system is a three-dimensional coordinate system, and the other coordinate axis, the y-axis, is perpendicular to the x-axis and the z-axis, and serves as the third coordinate axis direction.

[0073] In this embodiment, the predetermined incident wave may be, for example, a plane P wave, and the incident wave is incident at a certain angle to the boundary position between the predetermined medium and the non-preset medium, that is, the incident wave is incident at a certain angle to z 0 , and propagates in the x-axis-z-axis plane and is transmitted to each layer, so that the incident wave passes through the first boundary of each layer, where the incident wave can be 0 And each other first boundary is decomposed into P waves (longitudinal waves) and (S waves) shear waves.

[0074] Among them, S waves include SH waves (horizontal shear shear waves) and SV waves (vertical shear shear waves). The S waves involved in various embodiments of the present application are all SV waves.

[0075] In this embodiment, the density ρ of each layer in the underground medium is considered to be the same.

[0076] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0077] refer to Figure 2 The inversion method of the dielectric layer thickness and wave velocity of one embodiment of the present application comprises the following steps:

[0078] Step S201, determining the transverse waves and longitudinal waves into which the incident wave is decomposed based on the incident wave at the first boundary of the current layer of the preset medium, and determining the upward potential function coefficients and the downward potential function coefficients of the transverse wave and the longitudinal wave in the current layer using the displacement wave field and the stress wave field at the first boundary.

[0079] In this embodiment, at the first boundary of any layer of the preset medium, the incident wave is decomposed into P waves and SV waves, and a displacement wave field and a stress wave field are formed at the first boundary. The displacement wave field and the stress wave field can be used to determine the upward potential function coefficients and the downward potential function coefficients of the decomposed P waves and SV waves in the current layer.

[0080] In a specific example, the above-mentioned multi-layer underground medium is used as the preset medium. In the i-th layer, the first boundary is z i-1 , the second boundary is z i .

[0081] Among them, in z i-1 The displacement wave field formed at includes the first displacement wave field u along the x-axis direction i-1 , and the second displacement wave field w along the z-axis i-1 , at the same time, in z i-1 The stress wave field formed at includes the first stress wave field p along the x-axis direction. i-1 , and the second stress wave field r along the z-axis i-1 .

[0082] In this embodiment, at the first boundary z of the first layer of the underground medium 0 At 0 、w 0 、p 0 and r 0 , and the P-wave velocity α of the first layer can be determined 1 and SV wave velocity β 1 , and the first boundary z of the i+1th layer i u i 、w i 、p i and r i , and the P-wave velocity α of the i+1th layer i+1 and SV wave velocity β i+1 , according to the P-wave velocity α of the current i-th layer i and SV wave velocity β i , and the first boundary z of the current layer i-1 u i-1 、w i-1 、p i-1 and r i-1 Calculated, therefore, in this embodiment, the first boundary z of the current i-th layer is i-1 u i-1 、w i-1 、p i-1 and r i-1 , and the P-wave velocity α of the current i-th layer i and SV wave velocity β i as a known quantity.

[0083] Based on this, a local stiffness matrix can be constructed, and the stiffness matrix can be used to construct the relationship between the displacement wavelength and the stress wave field and the upgoing potential function coefficient and the downgoing potential function coefficient respectively.

[0084] Specifically, at the i-th layer, the respective potential functions of the P wave and the SV wave can be expressed as follows:

[0085]

[0086] in, represents the potential function of the P wave, represents the potential function of the SV wave, γ represents the angular frequency, j represents the imaginary unit, α i represents the P wave velocity of the i-th layer, β i represents the SV wave velocity of the i-th layer, represents the coefficient of the upward potential function of the P wave in the i-th layer, represents the coefficient of the downward potential function of the P-wave layer i, represents the coefficient of the upward potential function of the SV wave layer i, represents the coefficient of the downward potential function of the SV wave layer i, e represents the natural logarithm, represents the unit vector in the direction of the first coordinate axis shown, represents the unit vector in the direction of the second coordinate axis shown, Represents the unit vector in the direction of the third coordinate axis, l x It represents the cosine value of the propagation direction of the P wave relative to the x-axis, l z It represents the cosine value of the propagation direction of the P wave relative to the z-axis, m x Represents the cosine value of the propagation direction of the SV wave relative to the x-axis, m z Indicates the cosine value of the propagation direction of the SV wave relative to the z-axis.

[0087] In this embodiment, by decoupling the elastic wave equation, the following formula is obtained:

[0088]

[0089] Based on this, in the plane of P-wave and SV-wave propagation, u and w at any point in layer i can be expressed as follows:

[0090]

[0091] Among them, k represents the wave number in the horizontal direction, z represents the coordinate in the z-axis direction, and x represents the coordinate in the x-axis direction.

[0092] Furthermore, η in the above formula α and η βIt can be expressed as follows:

[0093]

[0094] Furthermore, the relationship between stress and displacement is constructed as follows:

[0095]

[0096] Where τ represents shear stress, σ represents normal stress, λ and μ are both Lame constants, and u ,z represents the derivative of the first shifted wave field in the x-axis direction, w ,x represents the derivative of the second shifted wave field in the x-axis direction, (xu) ,x Table 1 The derivative of the product of the first displacement wave field and the x-axis coordinate in the x-axis direction, w ,z Represents the derivative of the second shifted wave field in the z-axis direction.

[0097] Based on this, the relationship between u and w, as well as η α and η β After combining the expression of into the relationship between stress and displacement, the stress relationship is obtained as follows:

[0098]

[0099] In this embodiment, in the i-th layer, in order to determine the first boundary z i-1 and the second boundary is z i The displacement wave field and stress wave field at the position can be i-1 The z-axis coordinate at is taken as the depth origin, that is, z i-1 At z = 0, when the thickness of the i-th layer is h i When z i The coordinates of h i , because in z i-1 and z i The directions of the external normals are opposite, so the relationship between the displacement wave field and the stress wave field and the thickness can be determined as follows:

[0100]

[0101] Based on this, at the x-axis coordinate of 0, by setting z = 0 and z = h i Combining the above u and w relationship and stress relationship respectively, and applying the above displacement wave field and stress wave field and thickness relationship, the relationship between the upward potential function coefficient and the downward potential function system and the displacement wave field and stress wave field in the current layer can be determined as shown below:

[0102]

[0103] And further construct the first stiffness matrix M and the second stiffness matrix N as shown below:

[0104]

[0105] Among them, u i-1 represents the first displacement wave field of the i-1th layer, w i-1 represents the second displacement wave field at the first boundary of the i-1th layer, p i-1 represents the first stress wave field at the first boundary of the i-1th layer, r i-1 represents the second stress wave field at the first boundary of the i-1th layer, M represents the first stiffness matrix, N represents the second stiffness matrix, and M 1:2,1:4 Represents the elements of the first 4 columns in the first 2 rows of the first stiffness matrix, N 1:2,1:4 Represents the elements of the first 4 columns in the first 2 rows of the second stiffness matrix.

[0106] Based on this, since z can be measured 0 u 0 ,w 0 ,p 0 and r 0 , the first two rows of the first stiffness matrix M and the second stiffness matrix N, that is, the part not including the thickness, can be used to determine the upward potential function coefficient and the downward potential function coefficient of the current i-th layer.

[0107] Step S202, using the upward potential function coefficient and the downward potential function coefficient in the current layer, the displacement wavefield at the first boundary is decomposed into a lower downward longitudinal wave displacement wavefield, a lower downward shear wave displacement wavefield, a lower upward longitudinal wave displacement wavefield and a lower upward shear wave displacement wavefield.

[0108] In the embodiment of the present application, based on the upward potential function coefficients and downward potential function coefficients of the P wave and the SV wave determined in the above steps, as follows: Figure 1 As shown, the current i-th layer can be placed at the first boundary z i-1 The displacement wave field at i-1 ,w i-1 ) is further decomposed into the first boundary z i-1 Downward longitudinal displacement wave field on the lower side Downward shear wave displacement field Lower side upward longitudinal wave displacement wave field and the downward upgoing shear wave displacement field

[0109] Specifically, the P wave starts from the first boundary z of the current i-th layer i-1After propagating downward, each will be reflected at the first boundary of each layer, that is, the second boundary of the previous layer, and propagate upward when entering each subsequent layer. The upward propagating up-going wave formed by the P wave at the second interface includes the P wave formed by reflection, the SV wave formed by reflection, and the Figure 1 The reflected waves from other layers in the middle and below are transmitted upward to the second boundary of the current i-th layer to form the transmitted wave, among which the reflected waves formed by the reflection of each layer will return to the first boundary z of the i-th layer in turn. i-1 Place.

[0110] Based on this, Figure 1 As shown, at the first boundary z of the i-th layer i-1 There is a downward longitudinal displacement wave field on the lower side of Downward shear wave displacement field Lower side upward longitudinal wave displacement wave field and the downward upgoing shear wave displacement field The second boundary z at the i-th layer i There is an upper downward longitudinal wave displacement field in the upper layer Upward downward shear wave displacement field Upward longitudinal displacement wave field on the upper side and the upper side upward shear wave displacement field

[0111] Among them, the displacement wave field of the lower upward longitudinal wave The first waveform is the downward longitudinal displacement wave field on the lower side The first waveform propagates to the second boundary z i The P wave is reflected at the first boundary z and propagates back to the first boundary z. i-1 Lower side; Lower side upward shear wave displacement wave field The first waveform is the downward longitudinal displacement wave field on the lower side The first waveform propagates to the second boundary z i The SV wave is reflected at the first boundary z and propagates back to the first boundary z. i-1 Lower side.

[0112] Furthermore, the upper side upward longitudinal wave displacement wave field The first waveform is the downward longitudinal displacement wave field on the lower side Propagate down to the second boundary z i The P wave is reflected from the second boundary z i The upward shear wave displacement field on the upper side The first waveform is the downward longitudinal displacement wave field on the lower side Propagate down to the second boundary z i The SV wave is reflected at the second boundary z i Propagate back.

[0113] In this embodiment, based on the aforementioned determined relationship between the upgoing potential function coefficient and the downgoing potential function coefficient and the displacement wave field, the displacement wave field at the first boundary of the current layer can be decomposed.

[0114] Specifically, Figure 1 As shown, for the first boundary z of the i-th layer i-1 The displacement wave field at i-1 ,w i-1 ) is decomposed according to the decomposition formula shown below, and the corresponding downward longitudinal wave displacement wave field is obtained. Downward shear wave displacement field Lower side upward longitudinal wave displacement wave field and the downward upgoing shear wave displacement field

[0115]

[0116]

[0117] Among them, M 11 represents the element of the first row and first column of the first stiffness matrix, M 12 represents the element in the first row and second column of the first stiffness matrix, M 13 represents the element in the first row and third column of the first stiffness matrix, M 14 represents the element in the first row and fourth column of the first stiffness matrix, M 21 represents the element of the second row and first column of the first stiffness matrix, M 22 represents the element of the second row and second column of the first stiffness matrix, M 23 represents the element in the second row and third column of the first stiffness matrix, M 24 Represents the element in the 2nd row and 4th column of the first stiffness matrix.

[0118] It can be seen that in determining the downward longitudinal displacement wave field on the lower side Downward shear wave displacement field Lower side upward longitudinal wave displacement wave field and the downward upgoing shear wave displacement field When only the first two rows of the first stiffness matrix M are used, the thickness of the i-th layer h is not involved. i .

[0119] Step S203, using the first waveform of the lower upgoing longitudinal wave displacement wavefield or the first waveform of the lower upgoing shear wave displacement wavefield at the time when the first boundary appears, determine the current layer thickness between the first boundary and the second boundary, wherein the second boundary of the current layer is the first boundary of the next layer.

[0120] In the embodiment of the present application, the lower side of the first boundary of the current i-th layer will be After propagating downward, due to the reflection and transmission of other layers in the propagation direction, multiple corresponding layers will appear in sequence under the first boundary of the i-th layer over time. The waveform and multiple corresponding waveform.

[0121] Furthermore, the emergence The first waveform can be considered as the lower side of the first boundary of the i-th layer The upward displacement wave field of the P wave that propagates downward to the second boundary and then is reflected by the second boundary of the i-th layer and propagates back.

[0122] Furthermore, it can be determined The first waveform and the The first time difference between the first waveforms.

[0123] Based on this, the first time difference can be used to construct a first thickness formula as shown below, and the distance between the first boundary and the second boundary of the i-th layer can be determined according to the first thickness formula:

[0124]

[0125] Among them, α i represents the velocity of the longitudinal wave in the i-th layer, t pp Indicates the first time difference, represents the propagation direction of the longitudinal wave in the i-th layer.

[0126] It can be seen that h in the first thickness formula i That is, the distance between the first boundary and the second boundary in the i-th layer.

[0127] In another embodiment of the present application, the The first waveform can be considered as the lower side of the first boundary of the i-th layer The upward displacement wavefield of the SV wave that propagates downward to the second boundary and then is reflected by the second boundary of the i-th layer and propagates back.

[0128] Furthermore, it can be determined The first waveform and the Second time difference between the first waveforms.

[0129] Based on this, the second time difference can be used to construct a second thickness formula as shown below, and the distance between the first boundary and the second boundary of the i-th layer can be determined according to the second thickness formula:

[0130]

[0131] Among them, βi represents the velocity of the shear wave in the i-th layer, t ps represents the second time difference, represents the propagation direction of the shear wave in the i-th layer.

[0132] Step S204, using the current layer thickness to determine the displacement wavefield and stress wavefield at the second boundary, and decomposing the displacement wavefield at the second boundary into an upper downward longitudinal wave displacement wavefield, an upper downward shear wave displacement wavefield, an upper upward longitudinal wave displacement wavefield and an upper upward shear wave displacement wavefield at the second boundary.

[0133] In an embodiment of the present application, based on the thickness of the current layer determined in the aforementioned steps, each element in the first stiffness matrix M and the second stiffness matrix N can be further determined, thereby using the third row elements and the fourth row elements containing thickness in the first stiffness matrix M and the second stiffness matrix N to determine the displacement wavefield at the second boundary of the current layer, and decompose the displacement wavefield at the second boundary of the current layer to obtain the upper side downward longitudinal wave displacement wavefield, the upper side downward shear wave displacement wavefield, the upper side upward longitudinal wave displacement wavefield and the upper side upward shear wave displacement wavefield at the upper side of the second boundary of the current layer.

[0134] Specifically, for the current i-th layer, based on the determined thickness h of the i-th layer i , we can further determine the elements of the third and fourth rows of the first stiffness matrix M and the second stiffness matrix N that involve thickness, and use the current layer thickness h i , the upward potential function coefficient and the downward potential function coefficient in the current layer, and construct the following formula:

[0135]

[0136] Among them, u i represents the first displacement wave field at the second boundary of the i-th layer, w i represents the second displacement wave field at the first boundary of the i-th layer, p i represents the first stress wave field at the second boundary of the i-th layer, r i represents the second stress wave field at the first boundary of the i-th layer, M 3:4,1:4 Represents the elements of the first four columns in the last two rows of the first stiffness matrix, N 3:4,1:4 Represents the elements of the first 4 columns in the last 2 rows of the second stiffness matrix.

[0137] Based on this, the displacement wave field (u i ,w i ) and stress wave field (p i ,r i ).

[0138] Furthermore, the decomposition formula shown below is used to decompose and obtain the corresponding upper downgoing longitudinal wave displacement wave field: Upward downward shear wave displacement field Upward longitudinal displacement wave field on the upper side and the upper side upward shear wave displacement field

[0139]

[0140]

[0141] Among them, M 31 represents the element in the first row and third column of the first stiffness matrix, M 32 represents the element in the third row and second column of the first stiffness matrix, M 33 represents the element in the third row and third column of the first stiffness matrix, M 34 represents the element in the third row and fourth column of the first stiffness matrix, M 41 represents the element in the 4th row and 1st column of the first stiffness matrix, M 42 represents the element in the 4th row and 2nd column of the first stiffness matrix, M 43 represents the element in the 4th row and 3rd column of the first stiffness matrix, M 44 Represents the element in the 4th row and 4th column of the first stiffness matrix.

[0142] Step S205, determining a first reflectivity using the first waveform of the upper upgoing longitudinal wave displacement wavefield and the first waveform of the upper upgoing shear wave displacement wavefield, and determining the wave velocities of the shear wave and the longitudinal wave in the next layer respectively using the first reflectivity.

[0143] In the embodiment of the present application, by determining the upper side upward longitudinal wave displacement wave field and the upper side upward shear wave displacement field The displacement wave field of each downward longitudinal wave on the upper side The first reflectivity between them can be used to further determine the wave velocities of the P wave and the SV wave in the current layer.

[0144] Specifically, at the second interface of the current i-th layer, the upper downward longitudinal wave displacement wave field arriving is After the first waveform is reflected by the second interface, a P-wave reflection wave is formed. When the P-wave propagates back from the second interface, an upward longitudinal wave displacement wave field appears at the second interface. and The first waveform and The amplitude ratio between the first waveforms is taken as the first longitudinal wave reflectivity r of the reflected P wave. pp .

[0145] Furthermore, at the second interface of the current i-th layer, the upper downward longitudinal wave displacement wave field After the first waveform is reflected by the second interface, an SV wave reflection wave is formed. When the SV wave propagates back from the second interface, an upward shear wave displacement wave field appears at the second interface. and The first waveform and The amplitude ratio between the first waveforms is taken as the first shear wave reflectivity r of the reflected SV wave. ps .

[0146] Based on this, the first reflectivity relationship shown below is constructed, and the P wave velocity α of the i+1th layer is determined accordingly: i+1 and SV wave velocity β i+1 :

[0147]

[0148] Among them, r pp represents the first longitudinal wave reflectivity, r ps represents the first shear wave reflectivity, q represents the ray parameter, and a, b, c, d, D, F and H are all parameters.

[0149] In this embodiment, the parameter a can be obtained by using the following formula:

[0150] a=ρ(1-2β i+1 2 p 2 )-ρ(1-2β i 2 p 2 )

[0151] Where ρ represents the dielectric density of the layer.

[0152] Furthermore, the parameter b can be obtained by using the following formula:

[0153] b=ρ(1-2β i+1 2 q 2 )+2ρβ i 2 q 2

[0154] Where q represents the ray parameter.

[0155] Furthermore, the parameter c can be obtained using the following formula:

[0156] c=ρ(1-2β i 2 q 2 )+2ρβ i+1 2 q2

[0157] Furthermore, the parameter d can be obtained using the following formula:

[0158] d=2(ρβ i+1 2 -ρβ i 2 )

[0159] Furthermore, the parameter D can be obtained by the following formula:

[0160] D=EF+GHq 2

[0161] Furthermore, the parameter E can be obtained by the following formula:

[0162]

[0163] Furthermore, the parameter F can be obtained using the following formula:

[0164]

[0165] Furthermore, the parameter H can be obtained by the following formula:

[0166]

[0167] In another embodiment of the present application, in order to more accurately determine the P wave velocity α of the i+1th layer i+1 and SV wave velocity β i+1 , we can construct the following relationship between the second transverse wave reflectivity and the wave velocity of the i+1th layer, as well as the second reflectivity relationship between the second longitudinal wave reflectivity and the wave velocity of the i+1th layer:

[0168]

[0169] Among them, R pp represents the second longitudinal wave reflectivity, R ps represents the second shear wave reflectivity.

[0170] It can be seen that in this embodiment, the first longitudinal wave reflectivity r determined in the above embodiment is pp and the first shear wave reflectivity r ps As the calculated first reflectivity, the second longitudinal wave reflectivity R ps and the second shear wave reflectivity R ps As using the above relationship, the P wave velocity α i+1 and SV wave velocity β i+1 The second reflectivity is inferred.

[0171] Based on this, different P wave velocities α are selected within the preset wave velocity range, for example, [0.5 km / s, 5.5 km / s]. i+1 and SV wave velocity β i+1 Substitute the value of into the second reflectivity relationship, and determine the second longitudinal wave reflectivity R corresponding to each wave speed pp and the second shear wave reflectivity R ps .

[0172] Furthermore, from the different P wave speeds α i+1 and SV wave velocity β i+1 The value of the second reflectivity with the smallest error between the first reflectivity and the second reflectivity is determined and used as the P-wave velocity α i+1 and SV wave velocity β i+1 The final value of .

[0173] Specifically, the error formula is constructed as follows:

[0174] e(α i+1 ,β i+1 )=|R pp (α i+1 ,β i+1 )-r pp |+|R ps (α i+1 ,β i+1 )-r ps |

[0175] Among them, e represents the error, R pp (α i+1 ,β i+1 ) represents the second longitudinal wave reflectivity with respect to the P wave velocity α i+1 and SV wave velocity β i+1 The function of R ps (α i+1 ,β i+1 ) represents the second shear wave reflectivity with respect to the P wave velocity α i+1 and SV wave velocity β i+1 A function of, in this embodiment, may be the above-mentioned second reflectivity relationship.

[0176] Further, determine the second longitudinal wave reflectivity R pp and the first longitudinal wave reflectivity r pp The first error between the two and determines the second shear wave reflectivity R ps The first shear wave reflectivity r ps The second error, when within the above wave speed range, let the sum of the first error and the second error be the smallest P wave speed α i+1 and SV wave velocity β i+1The value of is taken as the final wave velocity value.

[0177] It can be seen that the inversion method of the medium layer thickness and wave velocity in the embodiment of the present application calculates the up-down potential function coefficients in the current layer of the preset medium based on the displacement wave field and stress wave field determined at the first boundary, and then uses the up-down potential function coefficients to decompose the displacement wave field, so as to determine the lower downgoing longitudinal wave displacement wave field and the lower upgoing longitudinal wave displacement wave field on the lower side of the first boundary. Based on this, the thickness of the current layer is determined by the time difference between the first waveform of the lower downgoing longitudinal wave displacement wave field and the first waveform of the lower upgoing longitudinal wave displacement wave field, so as to decompose the displacement wave field at the second boundary of the current layer by using the current layer thickness, realize the decomposition and extrapolation of the wave field, and then use the decomposed first waveform of the upgoing longitudinal wave displacement wave field on the upper side of the second boundary and the first waveform of the upper upgoing shear wave displacement wave field to determine the first reflectivity, and then use the first reflectivity to realize the determination of the wave velocity of the next layer.

[0178] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the described method.

[0179] It should be noted that some embodiments of the present application are described above. In some cases, the actions or steps recorded in the present application can be performed in an order different from that in the above-described embodiments and still achieve the desired result. In addition, the process depicted in the accompanying drawings does not necessarily require the specific order or continuous order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0180] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, an embodiment of the present application further provides an inversion device for dielectric layer thickness and wave velocity.

[0181] refer to Figure 3 The inversion device for dielectric layer thickness and wave velocity comprises: a coefficient determination module 301, a first decomposition module 302, a thickness determination module 303, a second decomposition module 304 and a wave velocity determination module 305;

[0182] The coefficient determination module 301 is configured to determine the transverse wave and the longitudinal wave into which the incident wave is decomposed based on the incident wave at the first boundary of the current layer of the preset medium, and determine the upward potential function coefficient and the downward potential function coefficient of the transverse wave and the longitudinal wave in the current layer by using the displacement wave field and the stress wave field at the first boundary;

[0183] The first decomposition module 302 is configured to decompose the displacement wavefield at the first boundary into a lower downward P-wave displacement wavefield, a lower downward S-wave displacement wavefield, a lower upward P-wave displacement wavefield and a lower upward S-wave displacement wavefield by using the upward potential function coefficient and the downward potential function coefficient in the current layer.

[0184] The thickness determination module 303 is configured to determine the thickness of the current layer between the first boundary and the second boundary by using the first waveform of the lower upgoing longitudinal wave displacement wave field or the first waveform of the lower upgoing shear wave displacement wave field at the time when the first boundary appears, wherein the second boundary of the current layer is the first boundary of the next layer;

[0185] The second decomposition module 304 is configured to determine the displacement wavefield and stress wavefield at the second boundary by using the current layer thickness, and decompose the displacement wavefield at the second boundary into an upper downgoing longitudinal displacement wavefield, an upper downgoing shear displacement wavefield, an upper upgoing longitudinal displacement wavefield and an upper upgoing shear displacement wavefield at the second boundary;

[0186] The wave velocity determination module 305 is configured to determine a first reflectivity using the first waveform of the upper upward longitudinal wave displacement wave field and the first waveform of the upper upward shear wave displacement wave field, and to determine the wave velocities of the shear wave and the longitudinal wave in the next layer respectively using the first reflectivity.

[0187] For the convenience of description, the above devices are described in terms of functions and are divided into various modules. Of course, when implementing the embodiments of the present application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0188] The device of the above embodiment is used to implement the corresponding inversion method of dielectric layer thickness and wave velocity in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be described in detail here.

[0189] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, an embodiment of the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the inversion method of the dielectric layer thickness and wave velocity as described in any of the above embodiments is implemented.

[0190] Figure 4A more specific schematic diagram of the hardware structure of an electronic device provided in this embodiment is shown, and the device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are connected to each other through the bus 1050 in the device.

[0191] The processor 1010 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application.

[0192] The memory 1020 may be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 may store an operating system and other application programs. When the technical solution provided in the embodiment of the present application is implemented by software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0193] The input / output interface 1030 is used to connect the input / output module to realize information input and output. The input / output module can be configured in the device as a component (not shown in the figure), or it can be externally connected to the device to provide corresponding functions. The input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0194] The communication interface 1040 is used to connect a communication module (not shown) to realize communication interaction between the device and other devices. The communication module can realize communication through a wired mode (such as USB, network cable, etc.) or a wireless mode (such as mobile network, WIFI, Bluetooth, etc.).

[0195] The bus 1050 includes a path that transmits information between the various components of the device (eg, the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040).

[0196] It should be noted that, although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040 and the bus 1050, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, it can be understood by those skilled in the art that the above device may also only include the components necessary for implementing the embodiment of the present application, and does not necessarily include all the components shown in the figure.

[0197] The device of the above embodiment is used to implement the corresponding inversion method of dielectric layer thickness and wave velocity in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be described in detail here.

[0198] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the inversion method of the medium layer thickness and wave velocity as described in any of the above embodiments.

[0199] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0200] The computer instructions stored in the storage medium of the above embodiment are used to enable the computer to execute the inversion method of dielectric layer thickness and wave velocity as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0201] Based on the same concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a computer program product, including computer program instructions. When the computer program instructions are run on a computer, the computer executes the inversion method of the dielectric layer thickness and wave velocity as described in any of the above embodiments, which has the beneficial effects of the corresponding method embodiments and will not be repeated here.

[0202] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0203] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present application difficult to understand, the known power supply / ground connection with the integrated circuit (IC) chip and other components may or may not be shown in the provided drawings. In addition, the device can be shown in the form of a block diagram to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present application will be implemented (that is, these details should be fully within the scope of understanding of those skilled in the art). In the case of elaborating specific details (e.g., circuits) to describe exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0204] Although the present application has been described in conjunction with specific embodiments of the present application, many replacements, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed.

[0205] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A method for inverting dielectric layer thickness and wave velocity, characterized in that: include: Determine a shear wave and a longitudinal wave based on an incident wave at a first boundary of a current layer of a preset medium, and determine an upward potential function coefficient and a downward potential function coefficient of the shear wave and the longitudinal wave in the current layer using a displacement wave field and a stress wave field at the first boundary; Decomposing the displacement wavefield at the first boundary into a lower downward P-wave displacement wavefield, a lower downward S-wave displacement wavefield, a lower upward P-wave displacement wavefield and a lower upward S-wave displacement wavefield under the first boundary by using the upward potential function coefficient and the downward potential function coefficient in the current layer; Determine the thickness of the current layer between the first boundary and the second boundary by using the first waveform of the lower upgoing longitudinal wave displacement wave field or the first waveform of the lower upgoing shear wave displacement wave field at the time when the first boundary appears, wherein the second boundary of the current layer is the first boundary of the next layer; Determine the displacement wave field and stress wave field at the second boundary by using the current layer thickness, and decompose the displacement wave field at the second boundary into an upper downward longitudinal wave displacement wave field, an upper downward shear wave displacement wave field, an upper upward longitudinal wave displacement wave field and an upper upward shear wave displacement wave field at the second boundary; The first reflectivity is determined using the first waveform of the upper upward longitudinal wave displacement wave field and the first waveform of the upper upward shear wave displacement wave field, and the wave velocities of the shear wave and the longitudinal wave in the next layer are determined using the first reflectivity.

2. The method according to claim 1, characterized in that The displacement wave field includes a first displacement wave field along a first coordinate axis in a preset coordinate system and a second displacement wave field along a second coordinate axis in the coordinate system, and the stress wave field includes a first stress wave field along the first coordinate axis and a second stress wave field along the second coordinate axis; The determining of the upward potential function coefficient and the downward potential function coefficient of the shear wave and the longitudinal wave in the current layer by using the displacement wave field and the stress wave field at the first boundary includes: Construct the first stiffness matrix and the second stiffness matrix as shown below, Wherein, M represents the first stiffness matrix, N represents the second stiffness matrix, e represents the natural logarithm, x represents the direction of the first coordinate axis, z represents the direction of the second coordinate axis, l x Represents the cosine value of the propagation direction of the longitudinal wave relative to the x-axis, m x represents the cosine value of the propagation direction of the shear wave relative to the x-axis, k represents the wave number in the horizontal direction, i represents the i-th layer of the medium, j represents the imaginary unit, α represents the velocity of the longitudinal wave, β represents the velocity of the shear wave, and h i represents the thickness of the i-th layer, The first stiffness matrix is ​​used to construct the relationship between the displacement wave field and the upward potential function coefficient and the downward potential function coefficient in the current layer as shown below, and the second stiffness matrix is ​​used to construct the relationship between the stress wave field and the upward potential function coefficient and the downward potential function coefficient in the current layer as shown below, so as to determine the upward potential function coefficient and the downward potential function coefficient in the current layer, Among them, u i-1 represents the first displacement wave field at the first boundary of the i-1th layer, w i-1 represents the second displacement wave field at the first boundary of the i-1th layer, p i-1 represents the first stress wave field at the first boundary of the i-1th layer, r i-1 represents the second stress wave field at the first boundary of the i-1th layer, represents the coefficient of the upward potential function of the longitudinal wave in the i-th layer, represents the coefficient of the downward potential function of the i-th layer of the longitudinal wave, represents the coefficient of the upward potential function of the i-th layer of the shear wave, represents the coefficient of the downward potential function of the i-th layer of the shear wave, M 1:2,1:4 Represents the elements of the first 4 columns in the first 2 rows of the first stiffness matrix, N 1:2,1:4 Represents the elements of the first 4 columns in the first 2 rows of the second stiffness matrix.

3. The method according to claim 2, characterized in that The method of decomposing the displacement wavefield at the first boundary by using the upward potential function coefficient and the downward potential function coefficient in the current layer into a downward longitudinal wave displacement wavefield below the first boundary, a downward shear wave displacement wavefield below, an upward longitudinal wave displacement wavefield below, and an upward shear wave displacement wavefield below, comprises: The relationship between the displacement wave field of the first boundary and the upward potential function coefficient and the downward potential function coefficient in the current layer is decomposed to obtain the decomposition formulas of the downward longitudinal wave displacement wave field, downward shear wave displacement wave field, upward longitudinal wave displacement wave field and upward shear wave displacement wave field of the first boundary as shown below: in, represents the unit vector in the direction of the first coordinate axis shown, represents the unit vector in the direction of the second coordinate axis shown, represents the displacement wave field of the upward P-wave below the first boundary of the i-1th layer, represents the downward longitudinal displacement wave field below the first boundary of the i-1th layer, represents the upward shear wave displacement field below the first boundary of the i-1th layer, represents the downward shear wave displacement field below the first boundary of the i-1th layer, M 11 represents the element of the first row and first column of the first stiffness matrix, M 12 represents the element in the first row and second column of the first stiffness matrix, M 13 represents the element in the first row and third column of the first stiffness matrix, M 14 represents the element in the first row and fourth column of the first stiffness matrix, M 21 represents the element of the second row and first column of the first stiffness matrix, M 22 represents the element of the second row and second column of the first stiffness matrix, M 23 represents the element in the second row and third column of the first stiffness matrix, M 24 Represents the element in the 2nd row and 4th column of the first stiffness matrix.

4. The method according to claim 1, characterized in that The method of determining the current layer thickness between the first boundary and the second boundary by using the first waveform of the lower side upgoing longitudinal wave displacement wave field or the first waveform of the lower side upgoing shear wave displacement wave field at the time when the first boundary appears comprises: Determine a first time difference between the emission time of the first waveform of the downward longitudinal displacement wave field below the first boundary of the current layer and the appearance time of the first waveform of the downward longitudinal displacement wave field, wherein the downward longitudinal displacement wave field is a wave field in which the longitudinal wave generated by the reflection of the first boundary of the next layer or the second boundary of the current layer after the downward longitudinal displacement wave field propagates reaches the lower side of the first boundary of the current layer; Determine the current layer thickness using the formula shown below, Among them, h i represents the thickness of the i-th layer, α i represents the velocity of the longitudinal wave in the i-th layer, t pp represents the first time difference, represents the propagation direction of the longitudinal wave in the i-th layer.

5. The method according to claim 4, characterized in that The method of determining the current layer thickness between the first boundary and the second boundary by using the first waveform of the lower side upgoing longitudinal wave displacement wave field or the first waveform of the lower side upgoing shear wave displacement wave field at the time when the first boundary appears, further includes: Determine a second time difference between the emission time of the first waveform of the downward longitudinal displacement wavefield below the first boundary of the current layer and the appearance time of the first waveform of the downward upward shear displacement wavefield, wherein the downward upward shear displacement wavefield is a wavefield in which the shear wave generated by the reflection of the first boundary of the next layer or the second boundary of the current layer after the downward longitudinal displacement wavefield propagates reaches the lower side of the first boundary of the current layer; Determine the current layer thickness using the formula shown below, Among them, β i represents the velocity of the shear wave in the i-th layer, t ps represents the second time difference, represents the propagation direction of the shear wave in the i-th layer.

6. The method according to claim 1, characterized in that The method of determining the displacement wave field and the stress wave field at the second boundary by using the current layer thickness includes: Using the current layer thickness, the upward potential function coefficient and the downward potential function coefficient in the current layer, the following formula is constructed to determine the displacement wave field and stress wave field at the second boundary: Among them, u i represents the first displacement wave field at the second boundary of the i-th layer, w i represents the second displacement wave field at the first boundary of the i-th layer, p i represents the first stress wave field at the second boundary of the i-th layer, r i represents the second stress wave field at the first boundary of the i-th layer, represents the coefficient of the upward potential function of the longitudinal wave in the i-th layer, represents the coefficient of the downward potential function of the i-th layer of the longitudinal wave, represents the coefficient of the upward potential function of the i-th layer of the shear wave, represents the coefficient of the downward potential function of the i-th layer of the shear wave, M 3:4,1:4 Represents the elements of the first four columns in the last two rows of the first stiffness matrix, N 3:4,1:4 Represents the elements of the first 4 columns in the last 2 rows of the second stiffness matrix.

7. The method according to claim 1, characterized in that The first reflectivity includes a first longitudinal wave reflectivity determined by an amplitude ratio between a first waveform of an upper downward longitudinal wave displacement wave field and a first waveform of an upper upward longitudinal wave displacement wave field, and a first shear wave reflectivity determined by an amplitude ratio between a first waveform of an upper downward longitudinal wave displacement wave field and a first waveform of an upper upward shear wave displacement wave field; The method of using the first reflectivity to determine the wave velocities of the transverse wave and the longitudinal wave in the next layer respectively includes: The longitudinal wave velocity and the shear wave velocity of the next layer are determined according to the reflectivity relationship shown below using the first longitudinal wave reflectivity and the first shear wave reflectivity. Among them, r pp represents the first longitudinal wave reflectivity, r ps represents the first transverse wave reflectivity, q represents the ray parameter, α i represents the velocity of the longitudinal wave in the i-th layer, α i+1 represents the velocity of the longitudinal wave in the i+1th layer, represents the propagation direction of the longitudinal wave in the i-th layer, represents the propagation direction of the shear wave in the i+1th layer, β i represents the velocity of the shear wave in the i-th layer, β i+1 represents the velocity of the transverse wave in the i+1th layer, a=ρ(1-2β i+1 2 p 2 )-ρ(1-2β i 2 p 2 ), b=ρ(1-2β i+1 2 q 2 )+2ρβ i 2 q 2 , c = ρ(1-2β i 2 q 2 )+2ρβ i+ 1 2 q 2 , d = 2(ρβ i+1 2 -ρβ i 2 ), D represents the cosine correlation term, ρ represents the medium density, and p represents the slowness of the wave field in the horizontal direction.

8. The method according to claim 7, characterized in that The method of using the first reflectivity to determine the wave speeds of the transverse wave and the longitudinal wave in the next layer respectively includes: Construct a relationship between the longitudinal wave velocity and the transverse wave velocity of the next layer and the second reflectivity as shown below, wherein the second reflectivity includes a second longitudinal wave reflectivity and a second transverse wave reflectivity, Among them, R pp represents the second longitudinal wave reflectivity, R ps represents the second shear wave reflectivity; Within the preset wave velocity range, the error between the second longitudinal wave reflectivity and the first longitudinal wave reflectivity is determined. When the sum of the errors between the second shear wave reflectivity and the first shear wave reflectivity is the smallest, the longitudinal wave velocity and shear wave velocity of the corresponding next layer are determined.

9. A device for inverting dielectric layer thickness and wave velocity, characterized in that: include: A coefficient determination module, a first decomposition module, a thickness determination module, a second decomposition module and a wave speed determination module; The coefficient determination module is configured to determine the transverse wave and the longitudinal wave into which the incident wave is decomposed based on the incident wave at the first boundary of the current layer of the preset medium, and determine the upward potential function coefficient and the downward potential function coefficient of the transverse wave and the longitudinal wave in the current layer by using the displacement wave field and the stress wave field at the first boundary; The first decomposition module is configured to decompose the displacement wavefield at the first boundary into a lower downward longitudinal displacement wavefield, a lower downward shear displacement wavefield, a lower upward longitudinal displacement wavefield and a lower upward shear displacement wavefield at the lower side of the first boundary by using the upward potential function coefficient and the downward potential function coefficient in the current layer; The thickness determination module is configured to determine the thickness of the current layer between the first boundary and the second boundary by using the first waveform of the lower upgoing longitudinal wave displacement wave field or the first waveform of the lower upgoing shear wave displacement wave field at the time when the first boundary appears, wherein the second boundary of the current layer is the first boundary of the next layer; The second decomposition module is configured to determine the displacement wavefield and stress wavefield at the second boundary by using the current layer thickness, and decompose the displacement wavefield at the second boundary into an upper downward longitudinal wave displacement wavefield, an upper downward shear wave displacement wavefield, an upper upward longitudinal wave displacement wavefield and an upper upward shear wave displacement wavefield at the second boundary; The wave velocity determination module is configured to determine a first reflectivity using a first waveform of an upper upward longitudinal wave displacement wave field and a first waveform of an upper upward shear wave displacement wave field, and to determine the wave velocities of shear waves and longitudinal waves in the next layer respectively using the first reflectivity.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executed by the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 8 is implemented.

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