Inversion method and device for Schelt wave high-order frequency dispersion curve of seabed node

Abstract

The invention discloses a method and a device for inverting a high-order frequency dispersion curve of a seafloor node Schelt wave. The method comprises the following steps: determining the distance between reference points according to seismic data arrangement information, and setting a plurality of reference points on a target section where a seismic survey line is located; according to the maximum offset distance and the minimum offset distance, common receiving point sub-gathers are screened from a common receiving point Schelt channel set of each seabed node, sub-gathers are intercepted from the common receiving point sub-gathers according to the reference point position information and the maximum distance, and the sub-gathers with the length not smaller than the minimum length form the gathers of the reference points; determining a frequency dispersion energy spectrum of each sub-gather in the reference point gather to obtain a superposed frequency dispersion energy spectrum of the reference point; and picking up a high-order frequency dispersion curve by superposing a frequency dispersion energy spectrum, and carrying out seismic inversion modeling. According to the method, through screening of available trace gathers of reference points and determination and superposition of frequency dispersion energy spectrums, an energy-enhanced superposed frequency dispersion energy spectrum is obtained, so that high-resolution seismic modeling can be realized based on extracted high-order frequency dispersion curve inversion.

Description

Technical Field

[0001] The invention relates to the technical field of offshore oil exploration seismic data acquisition and processing, and in particular to a method and device for inverting a Schulte wave high-order dispersion curve at a seafloor node. Background Art

[0002] In marine geological engineering, marine geophysical surveys, marine oil exploration and marine scientific research, it is crucial to obtain the shear wave velocity parameter of shallow seabed sediments. In the construction of marine engineering projects such as offshore oil platforms, offshore wind farms, submarine tunnel site selection and submarine pipeline monitoring, it is necessary to find or detect "soft" media, microcracks, active faults, etc. in the seabed sediments. The physical parameters of the shear wave velocity of seabed sediments can be used for indirect evaluation. Compared with direct detection methods such as submarine drilling, it has the advantages of high efficiency, low cost and profile detection. The shallow shear wave velocity parameters are necessary model prior information for marine geophysical multi-wave and multi-component seabed seismic exploration, and are also necessary parameter models for deep seabed shear wave velocity imaging to time difference calibration.

[0003] Seismic waves propagating along the seabed surface are a type of solid surface wave that is different from sound waves in the water in terms of the way it oscillates, and are called Scholte waves. The seismic Scholte wave method is a powerful means of exploring the shallow structure of the seabed, and extracting dispersion is the most critical step. Based on the dispersion curve, the shear wave velocity can be further obtained, thereby studying the seabed sedimentary structure. There are two main methods for extracting dispersion from traditional Scholte waves, one is the spectrum analysis of surface waves (SASW) method, and the other is the multi-channel surface wave analysis method (MASW). Summary of the invention

[0004] The inventors found that the methods of extracting dispersion using Scholte waves in the prior art have their own obvious shortcomings. The surface wave spectrum analysis method is very sensitive to coherent noise and the coupling of a single detector, while the multi-channel surface wave analysis method has a low horizontal resolution. At the same time, due to the integral effect and average effect of seismic wave propagation, that is, all media passing through during the propagation of seismic waves will have an impact on the seismic waves, so that the impact of the media in the non-target area will be superimposed on the target area, and the impact of the two will also partially offset each other. The traditional method of extracting dispersion curves using Scholte waves cannot solve the above problems, resulting in the inability to directly characterize profiles with strong lateral velocity changes.

[0005] The inventors have made the present invention and, through a specific implementation method, provide a method and device for inverting high-order dispersion curves of Schulte waves at seafloor nodes that overcome the above-mentioned problems or at least partially solve the above-mentioned problems. The method and device address the shortcomings of the integral averaging effect of traditional dispersion energy imaging, enhance and focus the lateral dispersion energy imaging resolution, and improve the inversion modeling accuracy of high-order weak energy dispersion curves.

[0006] In a first aspect, an embodiment of the present invention provides a method for inverting the high-order dispersion curve of Scholte waves of a subsea node, including:

[0007] Determine the spacing of reference points according to the seismic data arrangement information of the seismic line, and set a plurality of reference points on the target section where the seismic line is located according to the spacing;

[0008] Screen a common receiver subset of seismic traces with offset distances of seismic traces located between a preset minimum offset distance and a maximum offset distance from the Scholte wave common receiver gather of each subsea node, and intercept a subset of seismic traces with a distance between the seismic trace and the reference point not greater than a preset maximum length from the common receiver subset according to the position information of the reference point. The subset of seismic traces with a length not less than a preset minimum length intercepted forms the Scholte wave gather of the reference point;

[0009] Determine the dispersion energy spectrum of each subset of seismic traces in the Scholte wave gather of the reference point, and superimpose the dispersion energy spectra of each subset to obtain the superimposed dispersion energy spectrum of the reference point;

[0010] Pick up the high-order dispersion curve through the superimposed dispersion energy spectrum.

[0011] In a second aspect, an embodiment of the present invention provides a device for inverting the high-order dispersion curve of Scholte waves of a subsea node, including:

[0012] A reference point setting module, configured to determine the spacing of reference points according to the seismic data arrangement information of the seismic line, and set a plurality of reference points on the target section where the seismic line is located according to the spacing;

[0013] A reference point seismic gather extraction module, configured to screen a common receiver subset of seismic traces with offset distances of seismic traces located between a preset minimum offset distance and a maximum offset distance from the Scholte wave common receiver gather of each subsea node, and intercept a subset of seismic traces with a distance between the seismic trace and the reference point not greater than a preset maximum length from the common receiver subset according to the position information of the reference point. The subset of seismic traces with a length not less than a preset minimum length intercepted forms the Scholte wave gather of the reference point;

[0014] A superimposed dispersion energy spectrum establishment module, configured to determine the dispersion energy spectrum of each subset of seismic traces in the Scholte wave gather of the reference point, and superimpose the dispersion energy spectra of each subset to obtain the superimposed dispersion energy spectrum of the reference point;

[0015] A high-order dispersion curve picking module, configured to pick up the high-order dispersion curve through the superimposed dispersion energy spectrum.

[0016] In a third aspect, an embodiment of the present invention provides a computer storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-mentioned inversion method for the high-order dispersion curve of Scholte waves of a subsea node.

[0017] In a fourth aspect, an embodiment of the present disclosure provides a server, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor, when executing the program, implements the above-mentioned inversion method for the high-order dispersion curve of Scholte waves of a subsea node.

[0018] The beneficial effects of the above technical solutions provided by the embodiments of the present invention at least include:

[0019] (1) In the inversion method for the high-order dispersion curve of Scholte waves of a subsea node provided by the embodiment of the present invention, the positions and quantities of reference points are set by determining the spacing between reference points, and the Scholte wave channel set truncation parameters (including minimum offset, maximum offset, minimum length, and maximum length) are set. Multiple sub-channel sets that meet the conditions corresponding to a certain reference point are intercepted, and the superimposed dispersion energy spectrum of this reference point is obtained by superimposing the dispersion energy spectra of the sub-channel sets. This method weakens or eliminates the horizontal integration averaging effect generated by directly extracting the dispersion energy spectrum from a traditional single channel set, improves the resolution of the horizontal dispersion energy spectrum of Scholte waves of ocean bottom nodes (OBNs), and enhances high-order weak dispersion energy. Furthermore, the high-order dispersion curve is picked up from the obtained superimposed dispersion energy spectrum, providing a high-precision data basis for seismic inversion modeling, greatly improving the accuracy of Scholte wave inversion modeling, used to construct a more refined geological profile, and improving the exploration effect of the work area.

[0020] (2) Scholte waves are waves formed by the coupling of P waves and SV waves on the seabed surface. Since seawater cannot transmit shear waves, when the offset is too small, the main component of the seismic wave is the direct P wave and Scholte waves have not yet formed. Therefore, it is necessary to set the minimum offset Minoffset. When it is too small, there is a problem that the imaging effect deteriorates or even imaging cannot be performed due to too little data volume.

[0021] The maximum offset Maxoffset determines the accuracy of surface wave imaging. Because as the offset increases, the path that the seismic wave travels from the source to the geophone is longer, and the media on the path will all affect the seismic wave, which is called the integration effect. When the offset is too large, the integration effect is also stronger, and what the surface wave imaging shows is not only the response near the reference point and directly below it, but also the response of all underground media on the path from the shot point to the geophone. For high-resolution imaging of the dispersion energy of Scholte waves under a horizontal velocity variation model, Maxoffset should not be set too large.

[0022] When the length of the intercepted gather is too small, it is difficult to distinguish the curves of each order of the extracted dispersion energy spectrum. Therefore, the minimum length of the sub-gather needs to be set; the maximum length limits the maximum distance between the gather for extracting the dispersion energy spectrum and the reference point, which is used to improve the lateral resolution of the dispersion energy imaging.

[0023] The method for inverting the high-order dispersion curve of the Scholte wave of the subsea node provided by the embodiment of the present invention sets the interception parameters of the Scholte wave gather, including the minimum offset, the maximum offset, the minimum length, and the maximum length, which lays a data foundation for extracting the high-order dispersion curve for high-resolution imaging.

[0024] Other features and advantages of the present invention will be described in the following specification, and part of them will become obvious from the specification, or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained by the structures specifically pointed out in the written specification, claims, and drawings.

[0025] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0026] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0027] Figure 1 is the flowchart of the method for inverting the high-order dispersion curve of the Scholte wave of the subsea node in the embodiment of the present invention;

[0028] Figure 2 is the schematic diagram of the reference point setting in the embodiment of the present invention;

[0029] Figure 3 is the schematic diagram of the screening and interception of the Scholte wave gather of the reference point in the embodiment of the present invention;

[0030] Figure 4 is Figure 1 the specific implementation flowchart of step S13 in

[0031] Figure 5 is the structural schematic diagram of the device for inverting the high-order dispersion curve of the Scholte wave of the subsea node in the embodiment of the present invention. Detailed Embodiments

[0032] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0033] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not used to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0034] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0035] An embodiment of the present invention provides a method and device for inverting the high-order dispersion curve of Scholte waves of a seafloor node, which can extract high-order dispersion curves for high-resolution imaging.

[0036] Embodiment

[0037] An embodiment of the present invention provides a method for inverting the high-order dispersion curve of Scholte waves of a seafloor node, the process of which is as shown in Figure 1 and includes the following steps:

[0038] Step S11: Determine the spacing of reference points according to the seismic data arrangement information of the seismic line, and set a plurality of reference points on the target section where the seismic line is located according to the spacing.

[0039] First, extract the common receiver gather of Scholte waves of the OBN, and complete the assignment of header keywords such as gx, gy, sx, sy, and offset.

[0040] The full name of OBN is Ocean Bottom Node, abbreviated as subsea node. It is a multi-component seismograph laid on the seabed that can independently collect and record seismic signals. Read the SU or SEGY format data of the subsea seismograph and extract the common receiver gather of Scholte waves. At the same time, read the seismic record header data to obtain gx, gy, sx, sy, and offset. Among them, gx and gy are the coordinates of the shot point excitation position, sx and sy are the coordinates of the receiver position, and offset is the offset of the seismic data. These parameters will be used for subsequent screening and intercepting the common receiver gather of Scholte waves of the ocean bottom node OBN.

[0041] In some embodiments, the spacing of the reference points can be determined according to the shot interval in the seismic data arrangement information of the seismic line.

[0042] The number of reference points is the main factor affecting the imaging effect of the final result. The spacing can be set according to the engineering requirements. The spacing of the reference points should be set as small as possible to improve the resolution of the lateral dispersion energy spectrum of Scholte waves of the ocean bottom seismic node OBN and enhance the high-order weak dispersion energy. However, the spacing of the reference points should not be too small. Further, the spacing of the reference points is generally 1 to 3 times the shot interval.

[0043] See Figure 2 As shown, according to the position information of the detection area and the seismic data arrangement information, the target area of the project can be obtained, and the reference points are set in this target area. The layout of the reference point positions is bounded by the target area and is evenly arranged from one side to the other at the determined spacing.

[0044] The position of the reference point represents the actual position of a certain point in the detection area, and the subsea formation information obtained by subsequent data processing represents the information under the seabed at this point.

[0045] Step S12: Screen the common receiver sub-gather in the common receiver gather of Scholte waves of each subsea node where the seismic trace offset is between the preset minimum offset and maximum offset. According to the position information of the reference points, intercept the sub-gather in the common receiver sub-gather where the distance between the seismic trace and the reference point is not greater than the preset maximum length. The sub-gather with a length not less than the preset minimum length intercepted forms the Scholte wave gather of the reference point.

[0046] For the screening and extraction of the reference point Scholte wave channel set, four parameters need to be set: minimum length Minlength, maximum length Maxlength, minimum offset Minoffset, and maximum offset Maxoffset. Relative to the reference point, Minlength and Maxlength are selected according to the shot points and OBN nodes; for a common receiver gather, Minoffset and maxoffset are selected. Among them,

[0047] The minimum offset Minoffset refers to the minimum length limit of the seismic trace offset when intercepting data for a common receiver gather. The Scholte wave is a wave formed by the coupling of P waves and SV waves on the seabed surface. Since seawater cannot transmit shear waves, when the offset is too small, the main component of the seismic wave is the direct P wave and the Scholte wave has not yet formed. Therefore, the minimum offset Minoffset needs to be set. When it is too small, there will be problems such as poor imaging effect or even inability to image due to too little data volume.

[0048] The maximum offset Maxoffset refers to the maximum length limit of the seismic trace offset when intercepting data for a common receiver gather. The maximum offset Maxoffset determines the accuracy of surface wave imaging. Because as the offset increases, the path that the seismic wave travels from the source to the geophone becomes longer, and the media on the path will all affect the seismic wave, which is called the integral effect. When the offset is too large, the integral effect is also stronger, and the surface wave imaging will show not only the response near the reference point and directly below it, but also the responses of all underground media on the path from the shot point to the geophone. For high-resolution imaging of the Scholte wave dispersion energy under the lateral velocity variation model, Maxoffset should not be set too large.

[0049] When the length of the intercepted gather is too small, the curves of each order of the extracted dispersion energy spectrum are difficult to distinguish. Therefore, the minimum length of the sub-gather needs to be set; because the length of the sub-gather is limited by the maximum offset, the maximum length does not need to be set additionally. However, when it is too small, there will also be a situation where the imaging effect deteriorates due to too little data volume. Minoffset is generally taken as 200 - 700m, and Maxoffset is generally taken as 10 - 20 trace intervals. The trace interval is determined according to the seismic data arrangement information.

[0050] The minimum length Minlength refers to the minimum length limit for screening and intercepting the common receiver gather of the Scholte wave of a seafloor node OBN. When the length of the intercepted sub-gather is too small, the curves of each order of the extracted dispersion energy spectrum are difficult to distinguish.

[0051] The maximum length (Maxlength) refers to the maximum length limit when screening and intercepting the common receiver gather of Scholte waves for a seafloor node OBN. Maxlength limits the maximum distance between the gather for extracting the dispersion energy spectrum and the reference point, and is used to improve the lateral resolution of dispersion energy imaging. It is recommended to select the parameters: generally, Minlength is taken as 3 - 5 trace intervals, and Maxlength is generally the same as Maxoffset, also taken as 10 - 20 trace intervals.

[0052] See Figure 3 As shown, it is a schematic diagram of screening and intercepting the Scholte wave gather of the reference point. By setting the minimum offset and maximum offset, the selected common receiver sub - gather is the sub - gather composed of the black and gray seismic traces; taking the Figure 3 reference point in

[0053] The seafloor node Scholte wave high - order dispersion curve inversion method provided by the embodiments of the present invention sets the parameters for intercepting the Scholte wave gather of the seafloor node OBN, including the minimum offset, maximum offset, minimum length, and maximum length, laying a data foundation for extracting high - resolution imaging high - order dispersion curves.

[0054] Step S13: Determine the dispersion energy spectrum of each sub - gather in the Scholte wave gather of the reference point, and superimpose the dispersion energy spectra of each sub - gather to obtain the superimposed dispersion energy spectrum of this reference point.

[0055] See Figure 4 As shown, it may include the following steps:

[0056] Step S131: Obtain the phase velocity range and frequency range of the Scholte wave. According to the preset phase velocity interval and frequency interval, obtain multiple phase velocity values and multiple frequency values. Combine each phase velocity value with different frequency values to obtain multiple combinations of phase velocity values and frequency values.

[0057] Step S132: For each sub - gather in the Scholte wave gather of the reference point, determine the Scholte wave dispersion energy value of the sub - gather under the conditions of each combination of phase velocity values and frequency values, and form the Scholte wave dispersion energy spectrum.

[0058] Under the conditions of each combination of phase velocity values and frequency values, perform Fourier transform on each seismic trace in the sub - gather:

[0059] R i (x k , ω) = FFT(r i )

[0060] Among them, x k is the offset, ω is the frequency value, i is the serial number of the seismic trace in the sub-channel set, FFT(r i ) represents performing Fourier transform on the seismic trace r i , and R i represents the spectral value before normalization.

[0061] Perform amplitude normalization on the spectrum obtained by Fourier transform to obtain the normalized spectrum:

[0062]

[0063] Among them, || represents the modulo operation, and T i is the normalized spectrum of the i-th seismic trace in the sub-channel set.

[0064] Obtain the Scholte wave dispersion energy value from the normalized spectra of each seismic trace through the following formula:

[0065]

[0066] Among them, p is the serial number of the reference point, m is the serial number of the sub-channel set in the Scholte wave channel set of the reference point, v s is the phase velocity value, D′ p，m is the dispersion energy value of the m-th sub-channel set of the reference point p, i is the serial number of the seismic trace in the sub-channel set m, N is the total number of seismic traces in the sub-channel set m, and T i is the normalized spectrum of the i-th seismic trace in the sub-channel set m, and j is the imaginary unit.

[0067] By circularly calculating the corresponding dispersion energy values under the combined conditions of each phase velocity value and frequency value, the Scholte wave dispersion energy spectrum of the sub-channel set m in this spatio-temporal domain under this reference point p can be obtained:

[0068]

[0069] Among them, D p，m is the dispersion energy spectrum of the m-th sub-channel set of the reference point p, represents the sparse matrix, V represents the total number of phase velocity values, and Ω represents the total number of frequency values.

[0070] Step S133: Superimpose the dispersion energy spectra of each sub-channel set to obtain the superimposed dispersion energy spectrum of this reference point.

[0071] Through the following formula, superimpose the dispersion energy spectra of each sub-channel set to obtain the superimposed dispersion energy spectrum of this reference point:

[0072]

[0073] Among them, D p is the superimposed dispersion energy spectrum of the reference point p, and D p，m is the dispersion energy spectrum of the m-th sub-channel set of the reference point p, and M is the total number of sub-channel sets of the reference point p.

[0074] The calculation of the superimposed dispersion energy spectra of all reference points is completed through the above steps.

[0075] Step S14: Pick up the high-order dispersion curve through the superimposed dispersion energy spectrum.

[0076] Pick up the dispersion energy spectrum of the set frequency value through the superimposed dispersion energy spectrum; extract the high-order dispersion curve of this frequency value from this dispersion energy spectrum.

[0077] Further perform seismic inversion modeling based on the extracted high-order dispersion curve.

[0078] The method for inverting the high-order dispersion curve of the Scholte wave of the seafloor node provided by the embodiment of the present invention determines the position and number of reference points by determining the spacing of the reference points, sets the interception parameters of the Scholte wave channel set of the seafloor node OBN (including the minimum offset, maximum offset, minimum length, and maximum length), intercepts multiple sub-channel sets that meet the conditions corresponding to a certain reference point, and obtains the superimposed dispersion energy spectrum of this reference point by superimposing the dispersion energy spectra of the sub-channel sets. This method weakens or eliminates the transverse integral averaging effect generated by directly extracting the dispersion energy spectrum from the traditional single channel set, improves the resolution of the transverse dispersion energy spectrum of the Scholte wave of the seafloor seismic node OBN, and enhances the high-order weak dispersion energy. Furthermore, pick up the high-order dispersion curve from the obtained superimposed dispersion energy spectrum, providing a high-precision data basis for seismic inversion modeling, greatly improving the accuracy of the Scholte wave inversion modeling, used to construct a more refined geological profile, and improving the exploration effect of the work area.

[0079] Based on the inventive concept of the present invention, the embodiment of the present invention also provides a device for inverting the high-order dispersion curve of the Scholte wave of the seafloor node. The structure of the device is as Figure 5 shown, including:

[0080] A reference point setting module 51, configured to determine the spacing of the reference points according to the seismic data arrangement information of the seismic line, and set a plurality of reference points on the target section where the seismic line is located according to the spacing;

[0081] The reference point seismic trace gather extraction module 52 is used to screen out a common receiver sub-trace gather from the Scholte wave common receiver point traces of each seabed node, where the seismic trace offset in the common receiver sub-trace gather is between a preset minimum offset and a preset maximum offset. According to the position information of the reference point, a sub-trace gather is intercepted from the common receiver sub-trace gather, where the distance between the seismic trace and the reference point is not greater than a preset maximum length. The Scholte wave trace gather of the reference point is composed of the intercepted sub-trace gather with a length not less than a preset minimum length.

[0082] The stacked dispersion energy spectrum establishment module 53 is used to determine the dispersion energy spectrum of each sub-trace gather in the Scholte wave trace gather of the reference point, and stack the dispersion energy spectra of each sub-trace gather to obtain the stacked dispersion energy spectrum of the reference point.

[0083] The high-order dispersion curve picking module 54 is used to pick the high-order dispersion curve through the stacked dispersion energy spectrum.

[0084] Optionally, the reference point setting module 51, which determines the spacing of the reference points according to the seismic data arrangement information of the seismic line, is used for:

[0085] Determine the spacing of the reference points according to the shot spacing in the seismic data arrangement information of the seismic line, and the spacing is 1 to 3 times the shot spacing.

[0086] Optionally, the stacked dispersion energy spectrum establishment module 53, which determines the dispersion energy spectrum of each sub-trace gather in the Scholte wave trace gather of the reference point, is used for:

[0087] Obtain the phase velocity range and frequency range of the Scholte wave. According to the preset phase velocity interval and frequency interval, obtain a plurality of phase velocity values and a plurality of frequency values. Each phase velocity value is combined with different frequency values to obtain a plurality of phase velocity value and frequency value combinations. For each sub-trace gather in the Scholte wave trace gather of the reference point, determine the Scholte wave dispersion energy value of the sub-trace gather under the conditions of each phase velocity value and frequency value combination, and form the Scholte wave dispersion energy spectrum.

[0088] Optionally, the stacked dispersion energy spectrum establishment module 53, which determines the Scholte wave dispersion energy value of the sub-trace gather under the conditions of each phase velocity value and frequency value combination, is used for:

[0089] Under the conditions of each phase velocity value and frequency value combination, perform Fourier transform on each seismic trace in the sub-trace gather, perform amplitude normalization processing on the spectrum obtained by the Fourier transform to obtain a normalized spectrum, and obtain the Scholte wave dispersion energy value from the normalized spectra of each seismic trace.

[0090] Optionally, the stacked dispersion energy spectrum establishment module 53, which obtains the Scholte wave dispersion energy value from the normalized spectra of each seismic trace, is used for:

[0091] The Scholte wave dispersion energy value is obtained from the normalized spectra of each seismic trace by the following formula:

[0092]

[0093] where p is the serial number of the reference point, m is the serial number of the sub-trace set in the Scholte wave trace set of the reference point, x k is the offset, v s is the phase velocity value, ω is the frequency value, D′ p，m is the dispersion energy value of the m-th sub-trace set of the reference point p, i is the serial number of the seismic trace in the sub-trace set m, N is the total number of seismic traces in the sub-trace set m, T i is the normalized spectrum of the i-th seismic trace in the sub-trace set m, and j is the imaginary unit.

[0094] Optionally, the superposed dispersion energy spectrum building module 53, which constitutes the Scholte wave dispersion energy spectrum, is used for:

[0095] The Scholte wave dispersion energy spectrum is constituted as:

[0096]

[0097] where D p，m is the dispersion energy spectrum of the m-th sub-trace set of the reference point p, represents a sparse matrix, V represents the total number of phase velocity values, and Ω represents the total number of frequency values.

[0098] Optionally, the superposed dispersion energy spectrum building module 53, which superimposes the dispersion energy spectra of each sub-trace set to obtain the superposed dispersion energy spectrum of this reference point, is used for:

[0099] The dispersion energy spectra of each sub-trace set are superimposed to obtain the superposed dispersion energy spectrum of this reference point by the following formula:

[0100]

[0101] where D p is the superposed dispersion energy spectrum of the reference point p, D p，m is the dispersion energy spectrum of the m-th sub-trace set of the reference point p, and M is the total number of sub-trace sets of the reference point p.

[0102] Optionally, the high-order dispersion curve picking module 54, which picks the high-order dispersion curve through the superposed dispersion energy spectrum, is used for:

[0103] Picking the dispersion energy spectrum of a set frequency value through the superposed dispersion energy spectrum; extracting the high-order dispersion curve of this frequency value from this dispersion energy spectrum.

[0104] Regarding the device in the above embodiments, the specific manner in which each module performs operations has been described in detail in the embodiments related to the method, and will not be elaborated here.

[0105] Based on the inventive concept of the present invention, an embodiment of the present invention further provides a computer storage medium, in which computer-executable instructions are stored, and when the computer-executable instructions are executed by a processor, the above-mentioned method for inverting the high-order dispersion curve of the Schulte wave of the subsea node is implemented.

[0106] Based on the inventive concept of the present invention, an embodiment of the present invention further provides a server, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, the above-mentioned method for inverting the high-order dispersion curve of the Schulte wave of the subsea node is implemented.

[0107] Unless otherwise specifically stated, terms such as processing, computing, calculating, determining, displaying, etc. can refer to the actions and / or processes of one or more processing or computing systems, or similar devices, which operate on and transform data represented as physical (such as electronic) quantities in the registers or memories of the processing system into other data represented as physical quantities in the memories, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals can be represented using any of a variety of different technologies and methods. For example, the data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0108] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of the present disclosure. The appended method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy.

[0109] In the above detailed description, various features are combined in a single embodiment to simplify the present disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than those stated in each claim. On the contrary, as reflected by the appended claims, the present invention resides in less than all of the features of the disclosed single embodiment. Therefore, the appended claims are hereby expressly incorporated into the detailed description, where each claim stands alone as a separate preferred embodiment of the present invention.

[0110] Those skilled in the art should also understand that all the illustrative logical blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments herein can be implemented as electronic hardware, computer software, or a combination thereof. To clearly illustrate the interchangeability between hardware and software, the above-described various illustrative components, blocks, modules, circuits, and steps have been generally described in terms of their functions. Whether such a function is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Skilled technicians can implement the described functions in a flexible manner for each specific application, but such implementation decisions should not be construed as departing from the scope of protection of this disclosure.

[0111] The steps of the methods or algorithms described in conjunction with the embodiments herein can be directly embodied as hardware, software modules executed by a processor, or a combination thereof. The software modules can be located in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium well-known in the art. An exemplary storage medium is connected to the processor so that the processor can read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. The ASIC can be located in a user terminal. Of course, the processor and the storage medium can also exist as discrete components in the user terminal.

[0112] For software implementation, the technologies described in this application can be implemented using modules (e.g., procedures, functions, etc.) that execute the functions described in this application. These software codes can be stored in a memory unit and executed by a processor. The memory unit can be implemented inside the processor or outside the processor. In the latter case, it is communicatively coupled to the processor via various means, which are well-known in the art.

[0113] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but those of ordinary skill in the art should recognize that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, this term is covered in a manner similar to the term "including," as "including" is interpreted when used as a transitional word in the claims. In addition, any term "or" used in the claims or the specification is intended to mean "non-exclusive or."

Claims

1. An inversion method for the high-order dispersion curve of the Schulte wave of a subsea node, characterized in that, Comprising: Determine the spacing of reference points according to the seismic data arrangement information of the seismic line, and set a plurality of reference points on the target section where the seismic line is located according to the spacing; Screen out the common receiver sub-traces where the seismic trace offset is between the preset minimum offset and the maximum offset from the Scholte wave common receiver gather of each seafloor node. According to the position information of the reference points, intercept the sub-traces from the common receiver sub-traces where the distance between the seismic trace and the reference point is not greater than the preset maximum length. The sub-traces with a length not less than the preset minimum length form the Scholte wave gather of the reference point; Determine the dispersion energy spectrum of each sub-trace in the Scholte wave gather of the reference point, and superimpose the dispersion energy spectra of each sub-trace to obtain the superimposed dispersion energy spectrum of the reference point; Pick up the high-order dispersion curve through the superimposed dispersion energy spectrum.

2. The method according to claim 1, wherein The determining the spacing of reference points according to the seismic data arrangement information of the seismic line includes: Determine the spacing of reference points according to the shot spacing in the seismic data arrangement information of the seismic line, and the spacing is 1 to 3 times the shot spacing.

3. The method according to claim 1, wherein The minimum offset is 200 to 700 m; The maximum offset is 10 to 20 times the trace spacing in the seismic data arrangement information; The minimum length is 3 to 5 times the trace spacing.

4. The method according to claim 1, characterized in that, The determining the dispersion energy spectrum of each sub-trace in the Scholte wave gather of the reference point includes: Obtain the phase velocity range and frequency range of the Scholte wave. According to the preset phase velocity interval and frequency interval, obtain a plurality of phase velocity values and a plurality of frequency values. Each phase velocity value is combined with different frequency values to obtain a plurality of phase velocity value and frequency value combinations; For each sub-trace in the Scholte wave gather of the reference point, determine the Scholte wave dispersion energy value of the sub-trace under the conditions of each phase velocity value and frequency value combination, and form the Scholte wave dispersion energy spectrum.

5. The method according to claim 4, wherein The determining the Scholte wave dispersion energy value of the sub-trace under the conditions of each phase velocity value and frequency value combination includes: Under the conditions of each phase velocity value and frequency value combination, perform Fourier transform on each seismic trace in the sub-trace, perform amplitude normalization processing on the spectrum obtained by the Fourier transform to obtain the normalized spectrum, and obtain the Scholte wave dispersion energy value from the normalized spectra of each seismic trace.

6. The method according to claim 5, wherein The obtaining the Scholte wave dispersion energy value from the normalized spectra of each seismic trace includes: Obtain the Scholte wave dispersion energy value from the normalized spectra of each seismic trace through the following formula: Among them, p is the serial number of the reference point, m is the serial number of the sub-channel set in the Scholte wave channel set of the reference point, x k is the offset, v s is the phase velocity value, ω is the frequency value, D p ′ ,m is the dispersion energy value of the m-th sub-channel set of the reference point p, i is the serial number of the seismic trace in the sub-channel set m, N is the total number of seismic traces in the sub-channel set m, T i is the normalized spectrum of the i-th seismic trace in the sub-channel set m, and j is the imaginary unit.

7. The method according to claim 6, characterized in that, The forming the Scholte wave dispersion energy spectrum includes: The formed Scholte wave dispersion energy spectrum is: Among them, D p,m is the dispersion energy spectrum of the m-th sub-channel set of the reference point p, represents the sparse matrix, V represents the total number of phase velocity values, and Ω represents the total number of frequency values.

8. The method according to claim 1, characterized in that The superimposing the dispersion energy spectra of each sub-trace to obtain the superimposed dispersion energy spectrum of the reference point includes: Through the following formula, superimpose the dispersion energy spectra of each sub-trace to obtain the superimposed dispersion energy spectrum of the reference point: Among them, D p is the superposed dispersion energy spectrum of the reference point p, and D p,m is the dispersion energy spectrum of the m-th sub-channel set of the reference point p, and M is the total number of sub-channel sets of the reference point p.

9. The method according to any one of claims 1 to 8, characterized in that, The picking up the high-order dispersion curve through the superimposed dispersion energy spectrum includes: Pick up the dispersion energy spectrum of the set frequency value through the superimposed dispersion energy spectrum; Extract the high-order dispersion curve of the frequency value from the dispersion energy spectrum.

10. An inversion device for the high-order dispersion curve of the Schulte wave of a subsea node, characterized in that, Comprising: A reference point setting module, configured to determine the spacing of reference points according to the seismic data arrangement information of a seismic line, and set a plurality of reference points on a target section where the seismic line is located according to the spacing; A reference point seismic trace gather extraction module, configured to screen a common receiver sub-trace gather in which the seismic trace offset is between a preset minimum offset and a preset maximum offset from the Scholte wave common receiver trace gathers of each subsea node, and intercept, according to the position information of the reference points, a sub-trace gather in which the distance between the seismic trace and the reference point is not greater than a preset maximum length from the common receiver sub-trace gather, and the sub-trace gather with a length not less than a preset minimum length intercepted forms the Scholte wave trace gather of the reference point; A stacked dispersion energy spectrum establishing module, configured to determine the dispersion energy spectrum of each sub-trace gather in the Scholte wave trace gather of the reference point, and stack the dispersion energy spectra of the sub-trace gathers to obtain the stacked dispersion energy spectrum of the reference point; A high-order dispersion curve picking module, configured to pick a high-order dispersion curve through the stacked dispersion energy spectrum.

11. A computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, the method for inverting the high-order dispersion curve of the Scholte wave of the subsea node according to any one of claims 1 to 9 is implemented.

12. A server, characterized in that, Including: A memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, the method for inverting the high-order dispersion curve of the Scholte wave of the subsea node according to any one of claims 1 to 9 is implemented.

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