CN-122018002-A - Seismic frequency dispersion spectrum extraction method, system, terminal and storage medium

CN122018002ACN 122018002 ACN122018002 ACN 122018002ACN-122018002-A

Abstract

The invention relates to the technical field of seismic exploration imaging and discloses a method, a system, a terminal and a storage medium for extracting a seismic frequency dispersion spectrum, wherein the method comprises the steps of mapping a target seismic area into a target coordinate system and dividing the target seismic area to obtain triangular subunits; the method comprises the steps of calculating a frequency-Bezier conversion result of a triangle subunit, calculating a global frequency dispersion spectrum of a target seismic area based on the frequency-Bezier conversion result, converting time domain signals of the global frequency dispersion spectrum into wave number domain signals for different modes, performing wave number conversion, converting the wave number domain signals into time domain signals, performing phase velocity filtering processing to obtain a high-order frequency dispersion curve, and performing superposition processing on all the high-order frequency dispersion curves to obtain the target frequency dispersion spectrum. According to the invention, a surface integral process is introduced into the frequency-Bezier frame, so that the azimuth dependence of the seismic source radiation pattern is counteracted from a theoretical level, and the problem of dispersion measurement deviation under wide azimuth array coverage is solved.

Inventors

LI CHANGCHENG
REN HENGXIN
LI ZHENGBO
CHEN XIAOFEI

Assignees

南方科技大学

Dates

Publication Date: 20260512
Application Date: 20260121

Claims (10)

1. The seismic frequency dispersion spectrum extraction method is characterized by comprising the following steps of: acquiring a target seismic region, mapping the target seismic region into a target coordinate system, and dividing the target seismic region in the target coordinate system to obtain a plurality of triangular subunits; Calculating a frequency-Bezier transformation result of each triangular subunit by using the constructed expansion coefficients, and calculating a global frequency dispersion spectrum of the target seismic region according to each frequency-Bezier transformation result and the corresponding triangular subunit; aiming at different modes, converting the time domain signals of the global frequency dispersion spectrum into wave number domain signals, and performing wave number conversion on the wave number domain signals to obtain three-component data in each mode; And respectively converting each three-component data into a time domain signal, then carrying out phase velocity filtering processing to obtain corresponding high-order dispersion curves, and carrying out superposition processing on all the high-order dispersion curves to obtain a target dispersion spectrum of the target seismic region.
2. The method for extracting a seismic spectrum according to claim 1, wherein the acquiring a target seismic area maps the target seismic area into a target coordinate system, and the target seismic area is segmented in the target coordinate system to obtain a plurality of triangle subunits, specifically including: Acquiring a target seismic area, and constructing a target coordinate system by taking a seismic source of the target seismic area as an origin; Mapping the target seismic region into the target coordinate system, and defining a plurality of arrays in the target seismic region as nodes; and connecting all the neighbor nodes of the nodes, and dividing the target seismic area into a plurality of triangular subunits.
3. The method of seismic frequency dispersion spectrum extraction according to claim 1, wherein said utilizing the constructed plurality of expansion coefficients further comprises: Expanding the seismic displacement field of the target seismic region by using a column harmonic vector to obtain a first expansion coefficient of the target seismic region: ; second expansion coefficient: ; third expansion coefficient: ; fourth expansion coefficient: ; fifth expansion coefficient: ; sixth expansion coefficient: ; Seventh expansion coefficient: ; eighth expansion coefficient: ; Wherein, the A first expansion coefficient is represented and a second expansion coefficient is represented, A second expansion coefficient is indicated and is used, A third coefficient of expansion is indicated and, A fourth expansion coefficient is indicated and is indicated, A fifth expansion coefficient is indicated and is indicated, A sixth coefficient of expansion is indicated and, A seventh coefficient of expansion is indicated and, Represents an eighth expansion coefficient, k represents wave number, z represents depth, A radial three-component seismic record is represented, r represents the mid-seismic distance, Indicating the azimuth angle of the beam, Representing class 1 hanker's 1 st order hanker's function, Representing a three-component seismic record in the vertical direction, Representing class 1 hanker's 0 th order function, Representing the stiffness coefficient with respect to the vertical, Representing a tangential three-component seismic record, Representing class 1 hanker's order 2, Representing the stiffness coefficient with respect to the horizontal, Representing class 1, 3 rd order hanker function.
4. The method of extracting seismic frequency dispersion spectrum according to claim 3, wherein the frequency-Bessel transform result includes Love wave dispersion spectrum, rayleigh wave dispersion spectrum and leakage guided wave dispersion spectrum; the calculating the frequency-Bessel transformation result of each triangle subunit by using the constructed multiple expansion coefficients specifically comprises the following steps: Constructing a Love wave frequency spectrum by using the third expansion coefficient and the sixth expansion coefficient for each triangular subunit, wherein the Love wave frequency spectrum is used for representing the frequency dispersion information of the target seismic area in a tangential displacement component; constructing the Rayleigh wave dispersion spectrum by using the first expansion coefficient, the second expansion coefficient, the fourth expansion coefficient, the fifth expansion coefficient, the seventh expansion coefficient and the eighth expansion coefficient, wherein the Rayleigh wave dispersion spectrum is used for representing displacement components of the target seismic region in radial and vertical directions; And constructing the leakage guided wave frequency dispersion spectrum by using the first expansion coefficient, the second expansion coefficient, the fourth expansion coefficient, the fifth expansion coefficient, the seventh expansion coefficient and the eighth expansion coefficient, wherein the leakage guided wave frequency dispersion spectrum is used for representing a longitudinal wave speed structure of the target seismic region.
5. The method for extracting a seismic spectrum according to claim 4, wherein the calculating a global spectrum of the target seismic region according to each of the frequency-bessel transform results and the corresponding triangle subunit specifically includes: Calculating the triangular area of each triangular subunit, and multiplying the Rayleigh wave frequency dispersion spectrum of each triangular subunit by the corresponding triangular area to obtain a unit contribution value of each triangular subunit; and accumulating the contribution values of each unit to obtain the global dispersion spectrum of the target seismic region.
6. The method for extracting a seismic spectrum according to claim 1, wherein the converting the time domain signal of the global spectrum into a wave number domain signal for different modes, and performing wave number conversion on the wave number domain signal to obtain three-component data in each mode specifically comprises: Determining the frequency-phase velocity relation of each base-order dispersion energy according to the global dispersion spectrum; for different modes, removing a plurality of non-target base-order dispersion energies in a current mode to obtain the current type of target base-order dispersion energies, and converting a time domain signal of the global dispersion spectrum into a wave number domain signal; According to the frequency-phase velocity relation corresponding to the current type, carrying out wave number conversion on the target base-order dispersion energy in the wave number domain signal to obtain three-component data, and finally obtaining three-component data in each mode: ; where u represents three-component data, f represents frequency, Indicating that the j-th mode is to be used, The azimuth angle, z, the depth, e, the base of the natural logarithm, i, the imaginary unit, and c the light velocity.
7. The method for extracting a seismic spectrum according to claim 6, wherein the step of converting each of the three-component data into a time domain signal, respectively, and then performing phase velocity filtering to obtain a corresponding higher-order dispersion curve, and performing superposition processing on all the higher-order dispersion curves to obtain a target dispersion spectrum of the target seismic region, specifically comprises: Converting the target base-order dispersion energy of each three-component data into a time domain signal to obtain a green function correcting each mode to be 0 moment; In each green function, intercepting the waveform of the target base-order dispersion energy in each mode by using a time window to obtain a high-order dispersion curve; performing frequency dispersion spectrum superposition processing on the high-order frequency dispersion curves in each mode to obtain a target frequency dispersion spectrum of the target seismic region; The target frequency spectrum comprises frequency spectrums of the target seismic area in all modes.
8. A seismic spread spectrum extraction system for implementing the seismic spread spectrum extraction method according to any one of claims 1 to 7, the seismic spread spectrum extraction system comprising: the method comprises the steps of obtaining a target seismic area, mapping the target seismic area into a target coordinate system, and dividing the target seismic area in the target coordinate system to obtain a plurality of triangular subunits; The surface integral model is used for calculating the frequency-Bezier transformation result of each triangular subunit by using the constructed expansion coefficients, and calculating the global frequency dispersion spectrum of the target seismic area according to each frequency-Bezier transformation result and the corresponding triangular subunit; The mode separation model is used for converting the time domain signal of the global frequency dispersion spectrum into a wave number domain signal aiming at different modes, and carrying out wave number conversion on the wave number domain signal to obtain three-component data in each mode; and the frequency dispersion spectrum optimization model is used for respectively converting each three-component data into a time domain signal, then carrying out phase velocity filtering processing to obtain a corresponding high-order frequency dispersion curve, and carrying out superposition processing on all the high-order frequency dispersion curves to obtain a target frequency dispersion spectrum of the target seismic region.
9. A terminal comprising a memory, a processor and a seismic spread spectrum extraction program stored on the memory and executable on the processor, the seismic spread spectrum extraction program when executed by the processor implementing the steps of the seismic spread spectrum extraction method according to any one of claims 1-7.
10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a seismic spread spectrum extraction program, which when executed by a processor, implements the steps of the seismic spread spectrum extraction method according to any one of claims 1-7.

Description

Seismic frequency dispersion spectrum extraction method, system, terminal and storage medium Technical Field The invention relates to the technical field of seismic exploration imaging, in particular to a seismic frequency dispersion spectrum extraction method, a system, a terminal and a computer readable storage medium. Background The traditional dispersion curve extraction method (such as a double-station method and a path function method) generally has the problem that the resolution of a high-order mode is low, and high-order dispersion information is easy to be covered by the energy of a base-order mode or is interfered by noise, so that the inversion of an underground structure is lack of sufficient constraint, and multi-solution occurs. The current situation is greatly improved by the frequency-Bessel (F-J) transformation method, and the method realizes high-efficiency extraction of the frequency dispersion spectrum through column harmonic function expansion and remarkably improves the identification efficiency and the extraction precision of the high-order surface wave. However, the seismic source has complexity, and belongs to anisotropic sources with differences in all directions, so that the characteristic needs to be fully considered in the process of calculating the dispersion spectrum, the condition of extracting the dispersion spectrum from the natural seismic event record is harsh, the seismic source with enough magnitude needs to be relied on, and the propagation path from the seismic source to the array needs to be prevented from passing through natural low-pass filters such as ocean and the like so as to ensure that the high-order dispersion information as abundant as possible can be received. Accordingly, the prior art is still in need of improvement and development. Disclosure of Invention The invention mainly aims to provide a method, a system, a terminal and a computer readable storage medium for extracting a seismic dispersion spectrum, and aims to solve the problem that a frequency-Bessel method in the prior art needs high conditions when analyzing a seismic source, so that high-order dispersion information analyzed in a common seismic source environment has larger deviation. In order to achieve the above object, the present invention provides a method for extracting a seismic spread spectrum, the method comprising the steps of: acquiring a target seismic region, mapping the target seismic region into a target coordinate system, and dividing the target seismic region in the target coordinate system to obtain a plurality of triangular subunits; Calculating a frequency-Bezier transformation result of each triangular subunit by using the constructed expansion coefficients, and calculating a global frequency dispersion spectrum of the target seismic region according to each frequency-Bezier transformation result and the corresponding triangular subunit; aiming at different modes, converting the time domain signals of the global frequency dispersion spectrum into wave number domain signals, and performing wave number conversion on the wave number domain signals to obtain three-component data in each mode; And respectively converting each three-component data into a time domain signal, then carrying out phase velocity filtering processing to obtain corresponding high-order dispersion curves, and carrying out superposition processing on all the high-order dispersion curves to obtain a target dispersion spectrum of the target seismic region. Optionally, in the seismic frequency dispersion spectrum extraction method, the acquiring a target seismic region maps the target seismic region into a target coordinate system, and the target seismic region is segmented in the target coordinate system to obtain a plurality of triangle subunits, which specifically includes: Acquiring a target seismic area, and constructing a target coordinate system by taking a seismic source of the target seismic area as an origin; Mapping the target seismic region into the target coordinate system, and defining a plurality of arrays in the target seismic region as nodes; and connecting all the neighbor nodes of the nodes, and dividing the target seismic area into a plurality of triangular subunits. Optionally, the seismic frequency dispersion spectrum extracting method, wherein the using the constructed plurality of expansion coefficients further includes: Expanding the seismic displacement field of the target seismic region by using a column harmonic vector to obtain a first expansion coefficient of the target seismic region: ; second expansion coefficient: ; third expansion coefficient: ; fourth expansion coefficient: ; fifth expansion coefficient: ; sixth expansion coefficient: ; Seventh expansion coefficient: ; eighth expansion coefficient: ; Wherein, the A first expansion coefficient is represented and a second expansion coefficient is represented,A second expansion coefficient is indicated and is used,A third c