Near-seabed transverse wave exploration method and system based on active source earthquake

Abstract

The invention relates to the field of ocean geophysical exploration, and provides a near-seabed transverse wave exploration method and system based on an active source earthquake, and the method comprises the steps: collecting seismic data based on an active source earthquake system; interface waves recorded by the vertical component detector and the hydrophone component detector are separated; frequency dispersion curve energy spectrums of the interface waves recorded by the vertical component detector and the interface waves recorded by the hydrophone component detector are calculated respectively; obtaining an optimal weighting coefficient; obtaining a superposed frequency dispersion curve energy spectrum; and based on a half-wavelength method of Poisson's ratio constraint, carrying out inversion by using fundamental frequency information in the superposed frequency dispersion curve energy spectrum, and obtaining a transverse wave velocity structure of a near-seabed area below the measuring line. According to the method, the frequency dispersion curve is extracted by preferably selecting the data of the vertical component geophone and the data of the hydrophone component geophone with prominent fundamental frequency energy, and the transverse wave velocity inversion is carried out, so that a high-quality data basis is provided; the Poisson's ratio is introduced into inversion, and system errors caused by model simplification are effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of marine geophysical exploration, in particular to a near-seabed shear wave exploration method and system based on active source seismic. BACKGROUND

[0002] Since seawater is a fluid, its shear modulus is zero, and shear waves cannot propagate in fluid (seawater), therefore, the traditional active source offshore seismic exploration method does not use shear wave sources, in addition, it is difficult to directly obtain shear wave (S-wave) structure by hydrophone signal imaging, which is mostly P-wave (P-wave) structure. However, the unique information provided by shear waves about fluid, lithology, fractures and mechanical properties greatly reduces the uncertainty in the exploration and development of oil and gas, natural gas hydrates and seabed solid mineral resources, and plays an increasingly important role in deep water, complex reservoirs and unconventional resource exploration. With the advancement of technology, active source air gun excitation, combined with ocean bottom seismograph (OBS) receiving converted shear waves, can effectively obtain shear wave velocity on the crustal scale. In addition, using passive reception of natural seismic signals after earthquakes to realize shear wave imaging is also a mainstream means to obtain seabed shear wave velocity structure. The shear wave velocity of shallow sediments is the key to understanding seabed mechanical properties, assessing geological disaster risks and conducting fine resource exploration. Today, whether passive source shear wave imaging or converted shear wave imaging, the resolution is on the order of kilometers in depth, which cannot fully meet the needs of near-seabed engineering, mineral resource exploitation and scientific research. Therefore, a method and system are needed that can obtain the shear wave velocity of near-seabed sediments on a large scale and quickly.

[0003] Interface wave exploration is an important geophysical exploration method and an effective means of shear wave imaging. The propagation velocity of interface waves changes with frequency (or wavelength), low-frequency interface waves penetrate deep and reflect deep information, and high-frequency interface waves penetrate shallow and reflect shallow information. By analyzing the dispersion characteristics of interface waves propagating on the surface or seabed, the shear wave velocity structure of the shallow underground can be inferred, and this technology plays an important role in engineering geological investigation, resource exploration and geological disaster assessment. The interface wave exploration technology on land started earlier and developed more maturely. Marine interface wave exploration, especially based on marine seismic records of interface waves (Scholte waves, existing on the seawater-seabed interface), has relatively lagged behind on land, the main reasons being that marine seismic exploration has traditionally focused more on reflection or refraction waves, and it is not easy to observe interface waves. In addition, interface waves are often considered as low-frequency interference noise that needs to be filtered out, and the existence of seawater layer and the complexity of seawater-seabed interface make the excitation, propagation and identification of marine interface waves (Scholte waves) more complex than on land.

[0004] The present application aims at the low resolution, difficulty in acquisition and complex calculation of the existing near-sea bottom shear wave, and proposes a near-sea bottom shear wave exploration method and system based on active source seismic, which has important value in identifying the shallow stratum structure of the sea bottom, fluid identification, offshore resource exploration and engineering geological evaluation. SUMMARY

[0005] In view of the problems in the prior art, the present application proposes a near-sea bottom shear wave exploration method and system based on active source seismic to solve the problems of low resolution, difficulty in acquisition and complex calculation of the existing near-sea bottom shear wave.

[0006] In a first aspect, the present application provides a near-sea bottom shear wave exploration method based on active source seismic, comprising: Step S101: collecting seismic data based on active source seismic exploration to obtain four-component common receiver gather records; the four-component common receiver gather records include common receiver gather records of vertical component geophones and common receiver gather records of hydrophone component geophones; Step S102: separating interface waves of the vertical component geophone records from the common receiver gather records of the vertical component geophones, and separating interface waves of the hydrophone component geophone records from the common receiver gather records of the hydrophone component geophones; Step S103: calculating the energy spectrum of the dispersion curve of the interface waves of the vertical component geophone records and the energy spectrum of the dispersion curve of the interface waves of the hydrophone component geophone records, respectively; Step S104: scanning and stacking the energy spectrum of the dispersion curve of the interface waves of the vertical component geophone records and the energy spectrum of the dispersion curve of the interface waves of the hydrophone component geophone records to obtain an optimal weighting coefficient; Step S105: stacking the energy spectrum of the dispersion curve of the interface waves of the vertical component geophone records and the energy spectrum of the dispersion curve of the interface waves of the hydrophone component geophone records by using the optimal weighting coefficient to obtain a stacked dispersion curve energy spectrum; Step S106: identifying the peak value of the stacked dispersion curve energy spectrum to automatically obtain the fundamental frequency information in the stacked dispersion curve energy spectrum.

[0007] Step S107: using the fundamental frequency information in the stacked dispersion curve energy spectrum to perform inversion based on the half-wavelength method with Poisson's ratio constraint to obtain the shear wave velocity structure of the near-sea bottom area under the survey line.

[0008] Further, the step S103 comprises: dividing the seismic records into a plurality of frequency bands, and calculating the energy spectrum of the dispersion curve of the interface waves of the vertical component geophone records and the energy spectrum of the dispersion curve of the interface waves of the hydrophone component geophone records in each frequency band, respectively. Fourier transform in time direction to get frequency domain seismic record : (1) where, is the offset variable, is the time record, is the frequency; Equation (1) is expressed in the form of two partial products: (2) where, is the frequency domain seismic record, is the phase spectrum, is the amplitude spectrum, is the offset variable, is the frequency; Assuming that each Rayleigh wave component propagates with a phase velocity that is only related to its own frequency, the normalized spectrum that eliminates the influence of the amplitude spectrum is obtained by normalization : (3) where: , is the frequency, is the frequency corresponding to the Rayleigh wave phase velocity, is the frequency corresponding to the phase of the Rayleigh wave phase velocity, is the offset variable; Equation (3) is multiplied by , to obtain: (4) where: , is the scanning phase velocity, is the frequency, is the offset variable, is the frequency corresponding to the phase of the Rayleigh wave phase velocity, is the normalized spectrum; The stacking of actual seismic data over the entire offset can be written in discrete form: (5) where, is the matching degree of the tested phase velocity and the true phase velocity, is the minimum offset, is the maximum offset, is the scanning phase velocity, is the offset variable, is the frequency, for frequency corresponding Rayleigh wave phase velocity; corresponding to each frequency , and record the scanning phase velocity and frequency corresponding to each maximum value, and draw in the phase velocity-frequency coordinate system to obtain the dispersion curve energy spectrum.

[0009] Further, the step S104 comprises: setting a weighting coefficient , in the interval range, calculating the energy and frequency width of the base-order dispersion curve in the dispersion curve energy spectrum of the interface wave recorded by the vertical component detector and the dispersion curve energy spectrum of the interface wave recorded by the hydrophone component detector, obtaining the value that makes the base-order curve energy maximum and the frequency width maximum, and taking the value as the optimal weighting coefficient .

[0010] Further, the calculation formula for superimposing the dispersion curve energy spectrum of the interface wave recorded by the vertical component detector and the dispersion curve energy spectrum of the interface wave recorded by the hydrophone component detector by using the optimal weighting coefficient is: (6) wherein, is the superimposed dispersion curve energy spectrum, is the dispersion curve energy spectrum of the interface wave recorded by the vertical component detector, is the dispersion curve energy spectrum of the interface wave recorded by the hydrophone component detector, is the optimal weighting coefficient.

[0011] Further, the half-wavelength method based on Poisson's ratio constraint comprises determining the half-wavelength coefficient according to the corresponding relationship between Poisson's ratio and the half-wavelength coefficient.

[0012] Further, the calculation formula of Poisson's ratio is: (7) wherein, is Poisson's ratio, is the ratio of the longitudinal wave velocity to the transverse wave velocity.

[0013] Further, the half-wavelength method based on Poisson's ratio constraint uses the base frequency information in the superimposed dispersion curve energy spectrum to perform inversion according to the formula: (8) wherein, is the inversion depth of the th dispersion point in the superimposed dispersion curve energy spectrum, The half-wavelength coefficient, The first in the energy spectrum of the superimposed dispersion curve Average velocity of interface waves at each frequency scatter point The first in the energy spectrum of the superimposed dispersion curve The interface wave frequency of each frequency scatter point.

[0014] Secondly, this application provides a near-seafloor shear wave exploration system based on active-source seismic waves, the system comprising: Seismic data acquisition module: Based on seismic data acquired through active source seismic exploration, it obtains four-component common receiver gather records; the four-component common receiver gather records include the common receiver gather records of the vertical component geophone and the common receiver gather records of the hydrophone component geophone; Interface wave separation module: Separates the interface wave recorded by the vertical component detector from the common receiving point gather record of the vertical component detector, and separates the interface wave recorded by the hydrophone component detector from the common receiving point gather record of the hydrophone component detector. Dispersion curve energy spectrum calculation module: calculates the dispersion curve energy spectrum of the interface wave recorded by the vertical component detector and the dispersion curve energy spectrum of the interface wave recorded by the hydrophone component detector, respectively. Weighting coefficient calculation module: Scans and superimposes the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector to obtain the optimal weighting coefficient. Superimposed dispersion curve energy spectrum calculation module: The energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector are superimposed using the optimal weighting coefficient to obtain the superimposed dispersion curve energy spectrum. The module for obtaining fundamental frequency information in the superimposed dispersion curve energy spectrum automatically obtains the fundamental frequency information in the superimposed dispersion curve energy spectrum through peak identification. Inversion module: Based on the half-wavelength method constrained by Poisson's ratio, the module uses the fundamental frequency information in the energy spectrum of the superimposed dispersion curve to perform inversion and obtain the shear wave velocity structure in the near-seabed region below the survey line.

[0015] Thirdly, this application provides an electronic device, comprising: processor; Memory; And a computer program, wherein the computer program is stored in the memory, the computer program including instructions that, when executed by the processor, cause the electronic device to perform the method of the first aspect.

[0016] Fourthly, this application provides a computer-readable storage medium including a stored program, wherein the program, when executed, controls the device on which the computer-readable storage medium is located to perform the method described in the first aspect.

[0017] Based on the above-described invention, compared to the prior art, this application achieves the following technical effects: (1) The multi-component seismic exploration process of the seabed seismograph can realize the large-scale acquisition of near-seabed shear wave velocity. By reasonably deploying the observation system, the lateral resolution of shear wave velocity is improved, and high-precision shear wave velocity imaging of near-seabed area is realized.

[0018] (2) Selective shear wave velocity inversion is performed using detector data of the vertical component with prominent fundamental frequency energy and hydrophone component detector data. Appropriate weighting coefficients are obtained through energy scanning, and the dispersion curve energy spectra of the two component interface waves are superimposed to obtain the dispersion curve energy spectrum of the fundamental frequency with the maximum energy. This improves the signal-to-noise ratio and enhances the ability to identify effective signals. This method maintains good signal extraction performance even under complex seabed noise backgrounds, providing a high-quality data foundation for subsequent inversion.

[0019] (3) To address the problem of inaccurate estimation of half wavelength in traditional shear wave velocity inversion, the calculation model was improved by introducing Poisson's ratio, a parameter that significantly affects the actual propagation characteristics of interface waves. This effectively reduces the systematic error caused by model simplification in obtaining shear wave velocity from Scholte interface waves. This improvement significantly enhances the longitudinal resolution and reliability of the velocity inversion results, thereby increasing the accuracy of the inversion results.

[0020] (4) The method of this application has few and simple implementation conditions in the inversion calculation process, relies on the data obtained by multi-component seismic exploration of the seabed seismometer, and the lightweight calculation has low computing resource requirements, making it more suitable for rapid processing and large-scale data application in practical engineering applications. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating a near-seafloor shear wave exploration method based on active source seismic waves provided in an embodiment of this application. Figure 2These are the time domain diagrams of the interface waves of the hydrophone component (hyd component) and the interface wave of the vertical component (bhz component) provided in the embodiments of this application. Figure 3 This is the dispersion curve energy spectrum of the interface wave provided in the embodiments of this application; Figure 4 The transverse wave velocity structure is obtained by inversion using the half-wavelength method based on the Poisson ratio constraint of this application. Figure 5 This is a schematic diagram of the framework of a near-seafloor shear wave exploration system based on active source seismic data provided in this application embodiment; Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0023] To better understand the technical solution of this invention, the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0024] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0025] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0026] See Figure 1 This is a flowchart illustrating a near-seafloor shear wave exploration method based on active-source seismic data provided in this application. Figure 1 As shown, it mainly includes the following steps.

[0027] Step S101: Based on the seismic data acquired through active source seismic exploration, obtain four-component common receiver gather records; the four-component common receiver gather records include the common receiver gather records of the vertical component geophone and the common receiver gather records of the hydrophone component geophone.

[0028] Specifically, an artificial seismic source towed to the stern of a ship generates sound waves in the seawater near the sea surface, achieving rapid and large-area sound wave generation. Seabed seismometers are deployed on the seabed according to the station spacing set by the observation system to collect seismic signals excited by near-surface sound sources, thus obtaining seismic data from the field OBS stations. The OBS consists of a seated OBS on the seabed with four receiver components, including two vertical component detectors and a hydrophone component detector.

[0029] By setting appropriate station spacing, the lateral resolution of shear wave velocity was improved, enabling high-precision shear wave velocity imaging in the near-seabed region.

[0030] Step S102: Separate the interface wave recorded by the vertical component detector from the common receiving point gather record of the vertical component detector, and separate the interface wave recorded by the hydrophone component detector from the common receiving point gather record of the hydrophone component detector. The interface wave is a Scholte wave, a type of surface wave.

[0031] The interface wave recorded by the vertical component detector is denoted as the vertical component interface wave or the bhz component interface wave; the interface wave recorded by the hydrophone component detector is denoted as the hydrophone component interface wave or the hyd component interface wave. Figure 2 These are the time domain diagrams of the interface waves of the hydrophone component (hyd component) and the interface wave of the vertical component (bhz component) provided in the embodiments of this application.

[0032] Step S103: Calculate the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector, respectively.

[0033] earthquake records The frequency domain seismic record is obtained by performing a Fourier transform along the time direction. : (1) in, For offset variable, For time recording, For frequency; Formula (1) can be expressed as the product of two terms: (2) in, For frequency domain seismic records, For phase spectrum, For amplitude spectrum, For offset variable, For frequency; Assuming each Rayleigh wave component propagates at a phase velocity that depends only on its own frequency, normalization yields a normalized spectrum that eliminates the influence of the amplitude spectrum. : (3) in: , For frequency, For frequency The corresponding Rayleigh wave phase velocity, For frequency The phase of the corresponding Rayleigh wave phase velocity, For offset variables; Multiply formula (3) by ,get: (4) in: , For the scanning phase velocity, For frequency, For offset variable, For frequency The phase of the corresponding Rayleigh wave phase velocity, Normalized spectrum; The actual seismic data, superimposed over the entire offset, can be written in discrete form: (5) in, To determine the degree of matching between the tested phase velocity and the true phase velocity, Minimum offset distance The maximum offset distance, For the scanning phase velocity, For offset variable, For frequency, For frequency The corresponding Rayleigh wave phase velocity; Find the frequency corresponding to The maximum value is recorded, and the scanning phase velocity and frequency corresponding to each maximum value are recorded. The dispersion curve energy spectrum is obtained by plotting it in the phase velocity-frequency coordinate system.

[0034] Substitute the interface waves recorded by the vertical component geophone and the interface waves recorded by the hydrophone component geophone into the formulas (1)-(5) respectively to calculate the energy spectrum of the dispersion curve of the interface waves recorded by the vertical component geophone and the energy spectrum of the dispersion curve of the interface waves recorded by the hydrophone component geophone.

[0035] Step S104: Scan and superimpose the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector to obtain the optimal weighting coefficient.

[0036] Set weighting coefficients ,exist Within the specified interval, the energy and bandwidth of the fundamental dispersion curve in the energy spectrum of the interface wave recorded by the vertical component detector and the interface wave recorded by the hydrophone component detector are calculated to obtain the result that maximizes the energy and bandwidth of the fundamental dispersion curve. The value, will Value as the optimal weighting coefficient .

[0037] Step S105: The energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector are superimposed using the optimal weighting coefficient to obtain the superimposed dispersion curve energy spectrum.

[0038] The formula for superimposing the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector using the optimal weighting coefficients is as follows: (6) in, To superimpose the energy spectrum of the dispersion curve, The energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector. The energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector. These are the optimal weighting coefficients.

[0039] Step S106: For the superimposed dispersion curve energy spectrum, the fundamental frequency information in the superimposed dispersion curve energy spectrum is automatically obtained through peak identification.

[0040] Figure 3 This is the dispersion curve energy spectrum of the interface wave provided in the embodiments of this application. Wherein, Figure 3 In the middle (a), the dispersion curve energy spectrum of the interface wave of the hydrophone component (hyd component) is shown. Figure 3 In the middle (b), the dispersion curve energy spectrum of the interface wave is shown. Figure 3 In the middle (c), the energy spectrum of the superposition dispersion curve is shown. Figure 3 In (d), the red circled dots represent the basic order curves picked up based on the energy spectrum of the superposition dispersion curve.

[0041] Step S107: Based on the half-wavelength method constrained by Poisson's ratio, the fundamental frequency information in the energy spectrum of the superimposed dispersion curve is used for inversion to obtain the shear wave velocity structure in the near-seabed region below the survey line.

[0042] In the half-wavelength method, the basic principle for inverting shear wave velocity using surface wave dispersion data is as follows: under the assumption of a homogeneous half-space, the phase velocity of a surface wave can be approximately equivalent to the shear wave velocity of the medium; however, in a layered elastic half-space, the surface wave phase velocity corresponding to a certain wavelength is mainly affected by the shear wave velocity of the medium within that wavelength depth range. Therefore, the surface wave phase velocity corresponding to a certain wavelength can be approximately converted into the shear wave velocity at the corresponding depth. However, because the theoretical assumptions on which this method relies are relatively simplified, and the half-wavelength coefficients are given, the accuracy of its inversion results is limited.

[0043] In this application, the half-wavelength coefficient is determined based on the correspondence between Poisson's ratio and the half-wavelength coefficient. Table 1 shows the correspondence between Poisson's ratio and half-wavelength coefficient. Based on the obtained Poisson's ratio and Table 1, the corresponding half-wavelength coefficient can be directly obtained. When the obtained Poisson's ratio is not in Table 1, the nearest value in Table 1 is taken to match the value in Table 1. Then, the half-wavelength coefficient corresponding to the value in Table 1 is obtained as the half-wavelength coefficient corresponding to that Poisson's ratio, thus avoiding the error caused by the given half-wavelength coefficient in the traditional method.

[0044] The formula for calculating Poisson's ratio is: (7) in, Poisson's ratio, This is the ratio of P-wave velocity to S-wave velocity, obtained from multi-component seismic exploration using a submarine seismograph.

[0045] In addition to obtaining Poisson's ratio according to formula (7), it can also be obtained from actual measurement or empirical value.

[0046] The formula for inverting the half-wavelength method based on Poisson's ratio constraints using the fundamental frequency information in the energy spectrum of the superimposed dispersion curve is as follows: (8) in, The first in the energy spectrum of the superimposed dispersion curve Inversion depth of each frequency scatter point The half-wavelength coefficient, The first in the energy spectrum of the superimposed dispersion curve Average velocity of interface waves at each frequency scatter point The first in the energy spectrum of the superimposed dispersion curve The interface wave frequency of each frequency scatter point.

[0047] Table 1: Figure 4 The transverse wave velocity structure is obtained by inversion using the half-wavelength method with Poisson's ratio constraints according to this application. Figure 4As can be seen, the inverted shear wave velocity has high longitudinal resolution and reliability, realizing high-precision shear wave velocity imaging in the near-seabed region.

[0048] The example of this application achieves the following technical effects: (1) The shear wave velocity near the seabed can be obtained during the multi-component seismic exploration process of the seabed seismometer. By reasonably deploying the observation system, the lateral resolution of the shear wave velocity is improved, and high-precision shear wave velocity imaging of the near seabed area is realized.

[0049] (2) The transverse wave velocity is inverted by selecting the vertical component detector data and the hydrophone component detector data with prominent fundamental frequency energy. Appropriate weighting coefficients are obtained through energy scanning, and the dispersion curve energy spectra of the two component interface waves are superimposed to obtain the dispersion curve energy spectrum with the maximum fundamental frequency energy. This improves the signal-to-noise ratio and enhances the ability to identify effective signals. This method maintains good signal extraction performance even under complex seabed noise backgrounds, providing a high-quality data foundation for subsequent inversion.

[0050] (3) To address the problem of inaccurate estimation of half wavelength in traditional shear wave velocity inversion, the calculation model was improved by introducing Poisson's ratio, a parameter that significantly affects the actual interface wave propagation characteristics, effectively reducing the systematic error caused by model simplification in obtaining shear wave velocity from Scholte waves. This improvement significantly enhances the longitudinal resolution and reliability of the velocity inversion results, thereby improving the accuracy of the inversion results.

[0051] (4) The method of this application has simple implementation conditions in the inversion calculation process, and the lightweight calculation has low computing resource requirements, making it more suitable for fast processing and large-scale data application in practical engineering applications.

[0052] Corresponding to the above embodiments, this application also provides a near-seafloor shear wave exploration system for active source seismic sources.

[0053] See Figure 5 This is a structural block diagram of a near-seafloor shear wave exploration system based on an active-source seismic source, provided in an embodiment of this application. Figure 5 As shown, it mainly includes the following modules.

[0054] Seismic data acquisition module: Based on seismic data acquired through active source seismic exploration, it obtains four-component common receiver gather records; the four-component common receiver gather records include the common receiver gather records of the vertical component geophone and the common receiver gather records of the hydrophone component geophone; Interface wave separation module: Separates the interface wave recorded by the vertical component detector from the common receiving point gather record of the vertical component detector, and separates the interface wave recorded by the hydrophone component detector from the common receiving point gather record of the hydrophone component detector. Dispersion curve energy spectrum calculation module: calculates the dispersion curve energy spectrum of the interface wave recorded by the vertical component detector and the dispersion curve energy spectrum of the interface wave recorded by the hydrophone component detector, respectively. Weighting coefficient calculation module: Scans and superimposes the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector to obtain the optimal weighting coefficient. Superimposed dispersion curve energy spectrum calculation module: The energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector are superimposed using the optimal weighting coefficient to obtain the superimposed dispersion curve energy spectrum. The module for obtaining fundamental frequency information in the superimposed dispersion curve energy spectrum automatically obtains the fundamental frequency information in the superimposed dispersion curve energy spectrum through peak identification. Inversion module: Based on the half-wavelength method constrained by Poisson's ratio, the module uses the fundamental frequency information in the energy spectrum of the superimposed dispersion curve to perform inversion and obtain the shear wave velocity structure in the near-seabed region below the survey line.

[0055] It should be noted that the specific content involved in the embodiments of this application can be found in the description of the above method embodiments, and will not be repeated here for the sake of brevity.

[0056] Corresponding to the above embodiments, this application also provides an electronic device.

[0057] See Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 6 As shown, the electronic device 600 may include a processor 601, a memory 602, and a communication unit 603. These components communicate via one or more buses. Those skilled in the art will understand that the electronic device structure shown in the figures does not constitute a limitation on the embodiments of this application. It may be a bus-type structure or a star-type structure, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0058] The communication unit 603 is used to establish a communication channel, thereby enabling the electronic device to communicate with other devices.

[0059] The processor 601 serves as the control center of the electronic device, connecting various parts of the device via various interfaces and lines. It executes software programs and / or modules stored in the memory 602, and calls data stored in the memory to perform various functions and / or process data. The processor may be composed of integrated circuits (ICs), such as a single packaged IC or multiple packaged ICs with the same or different functions connected together. For example, the processor 601 may consist only of a central processing unit (CPU). In this embodiment, the CPU may have a single processing core or include multiple processing cores.

[0060] Memory 602 is used to store the execution instructions of processor 601. Memory 602 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0061] When the execution instructions in memory 602 are executed by processor 601, the electronic device 600 is able to perform some or all of the steps in the above method embodiments.

[0062] Corresponding to the above embodiments, this application also provides a computer-readable storage medium, wherein the computer-readable storage medium may store a program, wherein when the program runs, it can control the device where the computer-readable storage medium is located to execute some or all of the steps in the above method embodiments. In specific implementation, the computer-readable storage medium may be a magnetic disk, an optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0063] Corresponding to the above embodiments, this application also provides a computer program product containing executable instructions that, when executed on a computer, cause the computer to perform some or all of the steps in the above method embodiments.

[0064] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0065] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0066] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0067] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0068] The above description is merely a specific embodiment of this application. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A near-seafloor shear wave exploration method based on active-source seismic waves, characterized in that, include: Step S101: Based on the seismic data acquired through active source seismic exploration, obtain four-component common receiver gather records; the four-component common receiver gather records include the common receiver gather records of the vertical component geophone and the common receiver gather records of the hydrophone component geophone. Step S102: Separate the interface wave recorded by the vertical component detector from the common receiving point gather record of the vertical component detector, and separate the interface wave recorded by the hydrophone component detector from the common receiving point gather record of the hydrophone component detector. Step S103: Calculate the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector, respectively. Step S104: Scan and superimpose the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector to obtain the optimal weighting coefficients. Step S105: The energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector are superimposed using the optimal weighting coefficient to obtain the superimposed dispersion curve energy spectrum. Step S106: For the energy spectrum of the superimposed dispersion curve, the fundamental frequency information in the energy spectrum of the superimposed dispersion curve is automatically obtained through peak identification; Step S107: Based on the half-wavelength method constrained by Poisson's ratio, the fundamental frequency information in the energy spectrum of the superimposed dispersion curve is used for inversion to obtain the shear wave velocity structure in the near-seabed region below the survey line.

2. The method according to claim 1, characterized in that, Step S103 includes: earthquake records The frequency domain seismic record is obtained by performing a Fourier transform along the time direction. : （1）， in, For offset variable, For time recording, For frequency; Formula (1) can be expressed as the product of two terms: （2）， in, For frequency domain seismic records, For phase spectrum, For amplitude spectrum, For offset variable, For frequency; Assuming each Rayleigh wave component propagates at a phase velocity that depends only on its own frequency, normalization yields a normalized spectrum that eliminates the influence of the amplitude spectrum. : （3）， in: , For frequency, For frequency The corresponding Rayleigh wave phase velocity, For frequency The phase of the corresponding Rayleigh wave phase velocity, For offset variables; Multiply formula (3) by ,get: （4）， in: , For the scanning phase velocity, For frequency, For offset variable, For frequency The phase of the corresponding Rayleigh wave phase velocity, Normalized spectrum; The actual seismic data, superimposed over the entire offset, can be written in discrete form: （5）， in, To determine the degree of matching between the tested phase velocity and the true phase velocity, Minimum offset distance The maximum offset distance, For the scanning phase velocity, For offset variable, For frequency, For frequency The corresponding Rayleigh wave phase velocity; Find the frequency corresponding to The maximum value is recorded, and the scanning phase velocity and frequency corresponding to each maximum value are recorded. The dispersion curve energy spectrum is obtained by plotting it in the phase velocity-frequency coordinate system.

3. The method according to claim 1, characterized in that, Step S104 includes: Set weighting coefficients ,exist Within the specified interval, the energy and bandwidth of the fundamental dispersion curve in the energy spectrum of the interface wave recorded by the vertical component detector and the interface wave recorded by the hydrophone component detector are calculated to obtain the result that maximizes the energy and bandwidth of the fundamental dispersion curve. The value, will Value as the optimal weighting coefficient .

4. The method according to claim 3, characterized in that, The formula for superimposing the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector using the optimal weighting coefficients is as follows: （6）， in, To superimpose the energy spectrum of the dispersion curve, The energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector. The energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector. These are the optimal weighting coefficients.

5. The method according to claim 1, characterized in that, The half-wavelength method based on Poisson ratio constraints includes determining the half-wavelength coefficient according to the correspondence between Poisson ratio and half-wavelength coefficient.

6. The method according to claim 5, characterized in that, The formula for calculating Poisson's ratio is: （7）， in, Poisson's ratio, This is the ratio of the longitudinal wave velocity to the transverse wave velocity.

7. The method according to claim 1, characterized in that, The formula for inverting the half-wavelength method based on Poisson's ratio constraints using the fundamental frequency information in the energy spectrum of the superimposed dispersion curve is as follows: （8）， in, The first in the energy spectrum of the superimposed dispersion curve Inversion depth of each frequency scatter point The half-wavelength coefficient, The first in the energy spectrum of the superimposed dispersion curve Average velocity of interface waves at each frequency scatter point The first in the energy spectrum of the superimposed dispersion curve The interface wave frequency of each frequency scatter point.

8. A near-seafloor shear wave exploration system based on active-source seismic waves, characterized in that, include: Seismic data acquisition module: Based on seismic data acquired through active source seismic exploration, it obtains four-component common receiver gather records; the four-component common receiver gather records include the common receiver gather records of the vertical component geophone and the common receiver gather records of the hydrophone component geophone; Interface wave separation module: Separates the interface wave recorded by the vertical component detector from the common receiving point gather record of the vertical component detector, and separates the interface wave recorded by the hydrophone component detector from the common receiving point gather record of the hydrophone component detector. Dispersion curve energy spectrum calculation module: calculates the dispersion curve energy spectrum of the interface wave recorded by the vertical component detector and the dispersion curve energy spectrum of the interface wave recorded by the hydrophone component detector, respectively. Weighting coefficient calculation module: Scans and superimposes the energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector to obtain the optimal weighting coefficient. Superimposed dispersion curve energy spectrum calculation module: The energy spectrum of the dispersion curve of the interface wave recorded by the vertical component detector and the energy spectrum of the dispersion curve of the interface wave recorded by the hydrophone component detector are superimposed using the optimal weighting coefficient to obtain the superimposed dispersion curve energy spectrum. The module for obtaining fundamental frequency information in the superimposed dispersion curve energy spectrum automatically obtains the fundamental frequency information in the superimposed dispersion curve energy spectrum through peak identification. Inversion module: Based on the half-wavelength method constrained by Poisson's ratio, the module uses the fundamental frequency information in the energy spectrum of the superimposed dispersion curve to perform inversion and obtain the shear wave velocity structure in the near-seabed region below the survey line.

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

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method according to any one of claims 1 to 7.

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