Processing method and device for ocean P guided wave removal and mode separation

Abstract

The invention provides a processing method and device for ocean P guided wave removal and mode separation. The method comprises the following steps: determining a frequency dispersion energy spectrum corresponding to a marine seismic gather in a frequency-speed domain based on an original seismic record corresponding to the marine seismic gather in a time-space domain; and removing frequency dispersion energy except the specified P guided wave frequency dispersion mode in the frequency dispersion energy spectrum to obtain a target frequency dispersion energy spectrum. And inverting the target frequency dispersion energy spectrum to a time-space domain to obtain a target seismic record corresponding to the specified P guided wave frequency dispersion mode. And based on the original seismic record and the target seismic record, determining seismic data after the P guided wave frequency dispersion mode is removed. Wherein the extracted P guided wave seismic data is used for inversion of a frequency dispersion curve and a waveform so as to realize high-precision detection of a seabed longitudinal wave velocity structure or marine geological survey; the seismic data after the P guided wave frequency dispersion mode is removed is used for analyzing the influence of the P guided wave on the seismic signal and the amplitude spectrum of the seismic signal, and de-noised seismic data is provided for migration imaging of the reflected wave.

Description

Technical Field

[0001] The present application relates to the field of marine seismic exploration, and in particular to a processing method and device for marine P-guided wave removal and mode separation. Background Art

[0002] With the rapid development of seafloor seismic instruments, seismic exploration plays an increasingly important role in marine oil and gas resource exploration and geological surveys. In the collected marine seismic data, there is usually a dispersive wave type with strong energy following the first arrival of the P wave, which is called the "Guided-P wave". The generation of marine P guided waves is closely related to the seawater layer. Specifically, the seawater layer becomes a good waveguide layer because the top and bottom interfaces meet the free boundary and fluid-solid boundary conditions respectively, so that the reflected and refracted P waves and multiple waves propagating at different depths and with different wavelengths will "fall into" and interfere with each other, thus forming a dispersive wave type similar to a surface wave, which has a strong interference with the seismic reflection wave.

[0003] Since the discovery of P-waveguide, scholars in the field of natural earthquakes and exploration seismology have studied it from the perspectives of theoretical derivation and data processing and analysis. Most of them are based on the dispersion inversion of P-waveguide data and the V-wave in the underground medium. P The structure is predicted by tomography. However, there are relatively few studies on the removal of P-guided waves and the separation of dispersion modes. Nowadays, more and more seismic exploration operations are carried out in marine environments, and it is particularly important to develop technologies for the removal of marine P-guided waves and the separation of dispersion modes. This is mainly because 1) the extraction of pure P-guided wave records or records of a certain or multi-order dispersion mode will not be interfered by other wave types, which is conducive to obtaining higher-quality dispersion spectra and improving the inversion accuracy of dispersion curves. Moreover, the extraction of pure P-guided wave seismic waveforms is also conducive to the waveform inversion of the corresponding wave field; 2) P-guided waves will have significant interference and influence on some seismic reflection signals and spectral characteristics, which is not conducive to the accuracy of reflection imaging and should be reasonably removed from the original seismic records.

[0004] Therefore, for the special scenario of the marine environment, how to extract and remove the seismic data of the P-guide wave dispersion mode is the technical problem to be solved by this application. Summary of the invention

[0005] The purpose of this application is to provide a processing method and device for ocean P-guided wave removal and mode separation, which can extract and remove seismic data of P-guided wave dispersion mode from the collected original seismic traces for special scenarios in the ocean environment.

[0006] In order to achieve the above purpose, the embodiment of the present application is implemented as follows:

[0007] In a first aspect, a processing method for ocean P-guided wave removal and mode separation is provided, comprising:

[0008] Based on the original seismic records corresponding to the marine seismic gathers in the time-space domain, determining the dispersion energy spectrum corresponding to the marine seismic gathers in the frequency-velocity domain;

[0009] Removing the dispersion energy other than the specified P-waveguide dispersion mode in the dispersion energy spectrum to obtain a target dispersion energy spectrum;

[0010] Inverting the target dispersion energy spectrum to the time-space domain to obtain a target seismic record corresponding to the specified P waveguide dispersion mode;

[0011] Based on the original seismic record and the target seismic record, seismic data after removing the P-waveguide dispersion mode is determined.

[0012] In a second aspect, a device for processing marine seismic gathers is provided, comprising:

[0013] A dispersion module, used to determine the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain based on the original seismic records corresponding to the marine seismic gather in the time-space domain;

[0014] A removal module, used to remove the dispersion energy other than the specified P-guided wave dispersion mode in the dispersion energy spectrum to obtain a target dispersion energy spectrum;

[0015] An inversion module, used for inverting the target dispersion energy spectrum to the time-space domain to obtain a target seismic record corresponding to the specified P waveguide dispersion mode;

[0016] A processing module is used to determine the seismic data after removing the P-guide wave dispersion mode based on the original seismic record and the target seismic record.

[0017] In a third aspect, an embodiment of the present application provides an electronic device, comprising: a processor; and a memory configured to store computer-executable instructions, wherein the computer-executable instructions, when executed, cause the processor to execute the method described in the first aspect.

[0018] According to a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium is used to store computer-executable instructions, and the computer-executable instructions implement the method described in the first aspect when executed by a processor.

[0019] The embodiment of the present application is based on the original seismic record corresponding to the marine seismic gather in the time-space domain, and determines the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain; then, the dispersion energy except the specified P waveguide dispersion mode in the dispersion energy spectrum is removed to obtain the target dispersion energy spectrum, and the target dispersion energy spectrum is inverted to the time-space domain to obtain the seismic data corresponding to the target seismic record, that is, the P waveguide dispersion mode; finally, based on the original seismic record and the target seismic record, the seismic data after removing the specified P waveguide dispersion mode can be determined. Among them, the seismic data of the specified P waveguide dispersion mode can be used for the inversion of the dispersion curve and waveform of the marine environment with higher accuracy to determine the tomographic data of the longitudinal wave velocity structure of the seabed medium, which can be used as important reference data for the exploration and geological survey of marine resources (such as oil, gas, minerals, etc.). In addition, the seismic data after removing the specified P waveguide dispersion mode can be used to analyze the influence of P waveguide on seismic signals and their amplitude spectra, and can provide important denoised seismic data for the offset imaging of reflected waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a schematic diagram of the first flow chart of the method for processing marine seismic gathers according to an embodiment of the present application.

[0022] Figure 2 A second flow chart of the method for processing marine seismic gathers according to an embodiment of the present application.

[0023] Figure 3 Schematic diagram of the process of iterative calculation of high-resolution Radon transform coefficients using the conjugate gradient algorithm.

[0024] Figure 4 It is a schematic diagram of 3C synthetic seismic record;

[0025] Figure 5 It is a schematic diagram of the dispersion energy spectrum of 3C synthetic seismic records in the fv domain generated by high-resolution linear Radon transform;

[0026] Figure 6 It is a schematic diagram of the comparison of the dispersion energy spectra of the model data before and after the P-guided wave removal;

[0027] Figure 7is a schematic diagram of the dispersion spectrum of the synthetic record with the sea surface set as the absorbing boundary condition;

[0028] Figure 8 It is a schematic diagram of the seismic records before and after the P-guide wave is removed from the model data, and the P-guide wave record after removal;

[0029] Fig. 9 It is a schematic diagram of the comparison of single-channel seismic records and their amplitude spectra before and after the P-guide wave is removed from the model data;

[0030] Fig.10 It is a schematic diagram of the measured OBN common detection gathers;

[0031] Fig.11 It is a schematic diagram of the seismic record after the P-guide wave is removed from the measured data;

[0032] Fig.12 It is a schematic diagram of the P-guided wave seismic record removed from the measured data;

[0033] Fig.13 It is a schematic diagram of the comparison of the dispersion energy spectrum before and after removing the P-guided wave from the measured data;

[0034] Fig.14 It is a schematic diagram of comparing the amplitude spectra of single-channel seismic records before and after the P-guide wave removal of the measured data;

[0035] Fig.15 A schematic diagram of the structure of a processing device for marine seismic gathers according to an embodiment of the present application.

[0036] Fig.16 A schematic diagram of the structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this specification.

[0038] An embodiment of the present application provides a processing method for ocean P-guided wave removal and mode separation. Figure 1 Schematic diagram of the process, including the following steps:

[0039] S102, based on the original seismic records corresponding to the marine seismic gathers in the time-space domain, determining the dispersion energy spectrum corresponding to the marine seismic gathers in the frequency-velocity domain.

[0040] In this step, a high-resolution linear Radon transform (HLRT) is performed on the original seismic records corresponding to the marine seismic gathers in the time-space (tx) domain to determine the high-resolution Radon transform coefficients corresponding to the marine seismic gathers in the frequency-slowness (fp) domain; then, the high-resolution Radon transform coefficients corresponding to the marine seismic gathers in the frequency-slowness domain are mapped to the frequency-velocity (fv) domain for dispersion energy spectrum imaging to obtain the dispersion energy spectrum corresponding to the marine seismic gathers in the frequency-velocity domain.

[0041] This step belongs to the dispersion spectrum imaging of multi-channel seismic records based on the HLRT method; the theoretical details, calculation steps and dispersion spectrum imaging methods of the HLRT method involved are as follows:

[0042] For each channel of the two-dimensional tx-domain marine seismic gather d(t,x), after Fourier forward transform is performed along the time (t) axis to obtain the seismic data d(f,x) in the frequency-space domain, each single-frequency seismic data can be subjected to the following linear Radon transform (LRT):

[0043]

[0044] Correspondingly, the inverse transform takes the form shown below:

[0045]

[0046] Among them, x is the offset of the seismic trace, f and p are frequency and slowness respectively, i is the imaginary unit, and m represents the Radon transform coefficient. The researchers expressed equations (1) and (2) in matrix form as follows:

[0047] d=Lm, (3)

[0048] m adj =L T d, (4)

[0049] Where L = e i2πfpx is the forward transformation operator of the linear Radon transform; d represents the two-dimensional matrix of single-frequency seismic data; m represents the two-dimensional matrix of Radon coefficients. Since L is not an orthogonal matrix, L T is not a very good inverse transform operator, m adj is a low-resolution Radon matrix represented by a transpose or adjoint operator. To solve equation (3), it is necessary to minimize the objective function J.

[0050] J=‖d-Lm‖ 2 (5)

[0051] This problem can be solved using the least squares algorithm, and a damping factor λ needs to be added to form a stable inversion problem:

[0052] m=(L T L+λI) -1 L T d, (6)

[0053] The Radon transform at this time is essentially a standard Radon transform, and the obtained Radon transform coefficients belong to the least squares solution, and the resolution of the dispersion energy is not high. Therefore, on this basis, in order to best fit the model (dispersion energy) of the data, an iteratively reweighted conjugate gradient (IRCG) algorithm is also needed to calculate the high-resolution Radon transform coefficients. Through this pre-weighting, a sparse solution can be obtained, which can reduce the low resolution and spatial aliasing of the dispersion energy caused by insufficient wave field information; in this case, the high-resolution Radon transform coefficients can be solved by the following formula:

[0054]

[0055] Where I represents the identity matrix; W m W represents the weighting matrix of Radon transform coefficients; d Represents the weighting matrix for seismic data.

[0056] When performing the j-th IRCG iteration calculation, it can be represented by a diagonal matrix:

[0057] diag(W m ) j =|m j | 1 / 2 , (8)

[0058] diag(W d ) j =|r j | 1 / 2 , (9)

[0059] Among them, m j is the Radon transform coefficient obtained in the jth iteration; r j is the standard deviation of the residuals,

[0060] Further, refer to Figure 3 As shown in FIG. 1 , the process of calculating high-resolution Radon transform coefficients using the IRCG method includes the following steps:

[0061] 1. Perform Fourier transform on the two-dimensional tx domain seismic data along the time axis to extract single-frequency slices of the seismic data at each frequency;

[0062] 2. Give the initial damping factor λ, the maximum number of iterations Num, and set the initial iteration variable j to 1;

[0063] 3. Calculate the forward transform operator L of the Radon transform and its adjoint operator matrix L T According to formula (6), the least squares solution M is first calculated in the frequency domain 0 , and M 0 =W m m 0 As the initial solution;

[0064] 4. Start iterative calculation: When the iteration variable j <= Num, the following calculation process is executed:

[0065] ① Update the Radon transform coefficients and the weighting matrix W of seismic data according to equations (8) and (9) respectively m and W d ;

[0066] ②Based on the formula and formula Calculate variable KM j and variable y;

[0067] ③Use the conjugate gradient algorithm to solve the linear equation KM j = the root of y, and obtain the coefficient M of the jth iteration j ;

[0068] ④ Based on the formula Calculate the Radon transform coefficient m for the jth iteration j , which is the high-resolution Radon transform coefficient;

[0069] 5. All single-frequency slices are calculated in the above steps and arranged in the order of frequency to obtain the Radon transform coefficients of seismic data in the fp domain. Based on the mathematical relationship between velocity and slowness (v = 1 / p), the Radon transform coefficients can be mapped to the fv domain for dispersion spectrum imaging (modulo, normalize and image the Radon transform coefficients), and the dispersion spectrum of the marine seismic gather in the fv domain can be obtained.

[0070] S104, removing the dispersion energy other than the specified P-waveguide dispersion mode in the dispersion energy spectrum to obtain a target dispersion energy spectrum.

[0071] In this step, the range of the dispersion energy of the specified P-guided wave dispersion mode is selected from the dispersion energy spectrum corresponding to the frequency-velocity domain, and the dispersion energy values ​​outside the range are set to zero to obtain the target dispersion energy spectrum.

[0072] It should be noted that the specified P-waveguide dispersion mode is not limited to one, and may include all dispersion modes, or dispersion modes of a certain order or several orders. If the P-waveguide is to be removed, the range of the dispersion energy of all dispersion modes of the P-waveguide on the dispersion energy spectrum is selected; if a dispersion mode of the P-waveguide is to be separated, the range of the dispersion energy of the mode on the dispersion energy spectrum is selected.

[0073] S106, inverting the target dispersion energy spectrum into the time-space domain to obtain the target seismic record corresponding to the specified P waveguide dispersion mode.

[0074] This step inversely transforms the target dispersion energy spectrum in the fv domain to the tx domain to obtain the target seismic record. It should be understood that if the P waveguide is removed, the target seismic record is the entire P waveguide record; if a certain dispersion mode of the P waveguide is separated, the target seismic record is the seismic record of the mode.

[0075] Among them, the seismic data corresponding to the extracted specified P-waveguide dispersion mode can be used for tomographic imaging of the P-wave velocity structure of the seabed medium in the marine environment. For example, dispersion curves and waveforms can be inverted based on the seismic data corresponding to the specified P-waveguide mode to obtain tomographic data of the P-wave velocity structure of the seabed medium corresponding to the marine seismic track set. It should be noted that the inversion of dispersion curves and waveforms based on P-waveguide seismic data belongs to the prior art and will not be described in detail here.

[0076] S108, based on the original seismic records and the target seismic records, determine the seismic data after removing the P-waveguide dispersion mode.

[0077] In this step, the target seismic records are eliminated from the original seismic records to obtain seismic data after the specified P waveguide dispersion mode is removed.

[0078] Among them, the seismic data after removing the specified P-guide wave dispersion mode can be used to analyze the impact of P-guide wave on seismic signals and their amplitude spectra, and can provide important denoised seismic data for migration imaging of reflection waves.

[0079] In summary, the method of this embodiment determines the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain based on the original seismic record corresponding to the marine seismic gather in the time-space domain; then, the dispersion energy except the specified P waveguide dispersion mode in the dispersion energy spectrum is removed to obtain the target dispersion energy spectrum, and the target dispersion energy spectrum is inverted to the time-space domain to obtain the target seismic record; finally, based on the original seismic record and the target seismic record, the seismic data after removing the specified P waveguide dispersion mode can be determined. The seismic data corresponding to the specified P waveguide dispersion mode can be used to invert the dispersion curve and waveform of the marine environment with higher accuracy to determine the tomographic data of the longitudinal wave velocity structure of the seabed medium, which can be used as important reference data for marine resource (such as oil, gas, minerals, etc.) exploration and geological survey. In addition, the seismic data after removing the specified P waveguide dispersion mode can be used to analyze the influence of P waveguide on seismic signals and their amplitude spectra, and can provide important denoised seismic data for the offset imaging of reflected waves.

[0080] The method of this embodiment is introduced below in combination with actual application scenarios.

[0081] The process of this application scenario is as follows Figure 2 The main steps include:

[0082] S01: Input original seismic data (multi-channel seismic records);

[0083] S02: Perform high-resolution linear Radon transformation on the tx domain seismic records and calculate the high-resolution Radon domain transformation coefficients;

[0084] S03: Map the high-resolution Radon transform coefficients to the fv domain to generate a fv domain dispersion energy spectrum image;

[0085] S04: Select the range of the target wave field on the fv domain dispersion energy spectrum;

[0086] S05: removing the dispersion energy outside the target range on the dispersion energy spectrum to generate a target dispersion energy spectrum;

[0087] S06: Inversely transform the target dispersion energy spectrum into the tx domain to obtain the target seismic record;

[0088] S07: removing the target seismic record from the original seismic record;

[0089] S08: Output seismic data (including the removed target seismic record and the difference record between the original record and the target record).

[0090] In order to verify the effectiveness of the method of this embodiment, model data is used to test this application scenario.

[0091] Table 1 shows a two-dimensional (2D) shallow sea layered medium model set up according to the survey results of the actual seabed medium.

[0092] Table 1 Shallow sea layered medium model parameters

[0093]

[0094] Table 2 shows the parameters used in the finite difference wavefield simulation.

[0095] Table 2 Wave field simulation parameters

[0096]

[0097]

[0098] According to the parameters in Table 1 and Table 2, the following can be simulated: Figure 4 The two-dimensional three-component (2D-3C) seismic record shown in FIG. 1 (the above work corresponds to step S01). The simulated 2D-3C seismic record is Figure 3 The process in Calculate high-resolution Radon transform coefficients and generate Figure 5 The fv domain dispersion spectrum image shown (the above work corresponds to steps S02 to S03). In order to accurately determine the distribution characteristics and range of the ocean P-guided wave on the dispersion spectrum, the theoretical dispersion curves of various dispersion wave types in the ocean environment, including: P-guided wave (Guided-P wave), organ-pipe wave (Organ-pipe wave, also known as "∑ mode") and Scholte wave, can be calculated based on the solution of the roots of the fluid-solid interface wave dispersion equation, and they are projected on the dispersion spectrum ( Figure 5 d~f). As can be seen from the figure, P waveguide has multi-order dispersion modes, and its dispersion energy is mainly distributed in the velocity range from the seawater layer longitudinal wave velocity to the maximum solid longitudinal wave velocity, which is quite different from the dispersion energy of other wave types. Based on the above characteristic analysis, taking the Z component as an example, the P waveguide in the seismic data is removed. The specific removal method is: 1) First, select the range where the P waveguide dispersion energy is located in the fv domain dispersion energy spectrum ( Figure 6 a, corresponding to step S04); 2) by keeping the Radon coefficients within the selected target range unchanged and setting the Radon coefficients outside the target range to 0, a target dispersion energy spectrum is generated (corresponding to step S05); 3) the target dispersion energy spectrum is inversely transformed to the tx domain to obtain the target seismic record, i.e., the separated P waveguide record (such as Figure 8 c, corresponding to step S06); 4) subtracting the target seismic record from the original seismic record to obtain the seismic record after removing the P waveguide (such as Figure 8b, corresponding to step S07). It is worth noting that if a certain order dispersion mode of the P waveguide is to be separated, in step S04, it is only necessary to select the dispersion energy of the mode, and then proceed to steps S05 to S07; since these operations are basically the same as the above contents, they are not shown in detail here.

[0099] Figure 6 b shows the dispersion energy spectrum of the seismic record after removing the P-guide wave, which is different from the dispersion energy spectrum of the original seismic record ( Figure 6 a) By comparison, we can see that: 1) after the P-guided wave is removed, there is no more multi-mode dispersion energy in the corresponding speed and frequency range, but there is a certain amount of direct wave (marked by the green arrow), refracted wave, reflected wave and multiple reflection (red arrow area) energy. To verify the accuracy of the above results, the seismic wave field under the condition of sea surface as absorbing boundary is also simulated, and P-guided wave will not be generated at this time. Figure 7 The dispersion spectrum in this case is shown; the energy of direct waves, refracted waves, and reflected waves can be clearly seen in the corresponding areas, and their characteristics are similar to Figure 6 (b) is similar. The difference is that the energy of multiple waves is missing; 2) After the P waveguide is removed, the energy of the body wave is prominent, making Figure 6 (b) The dispersion energy of the surface waves and organ pipe leakage modes appears relatively weak.

[0100] Figure 8 The seismic records before and after the removal of the P-guided wave and the removed P-guided wave records are shown respectively. It can be seen from the figure that: 1) after the P-guided wave is removed, the direct wave, refracted wave, some reflected waves and the phase axis of multiple reflections can be intuitively presented on the seismic record; 2) due to the lack of the strong energy cover of the P-guided wave, from a visual point of view, Figure 8 The Scholte wave record in (b) is Figure 8 (a) is clearer. To intuitively understand the influence of P waveguide on other seismic signals, Fig. 9 The single-channel seismic records and their amplitude spectra before and after the removal of P-waveguides are compared in the paper. The comparison results show that after the removal of P-waveguides, the dispersion waveform characteristics are significantly weakened, and the amplitude of the seismic signal is significantly reduced, especially in the high-frequency range; this is because P-waveguides are formed by multiple reflections and refractions of P waves "trapped" in the water layer and coupled with each other, and can carry a large amount of seismic energy. In addition, by comparing the amplitude spectra before and after the removal of P-waveguides, it can be found that after the removal of P-waveguides, the significant notch characteristics appearing on the amplitude spectrum are weakened.

[0101] Furthermore, in order to verify the practicality of the method of this embodiment, the P-guided wave removal test can be performed on the 4C-OBN data collected in the Chengdao shallow water area according to the test process of the model data. The data test still takes the Z component as an example.

[0102] Fig.10 The display shows the common detection point gather of a certain OBN. It can be seen that there are significant P-guide waves in the seismic record, which is consistent with the model data. Figure 2 The technical process shown in the figure is as follows: 1) Input the original earthquake record ( Fig.10 , corresponding to step S01), and using high-resolution linear Radon transform to generate the dispersion energy spectrum of the seismic record in the fv domain ( Fig.13 a, corresponding to steps S02 to S03). From the dispersion energy spectrum, multi-order dispersion energy can be observed in the range of phase velocity > 1500m / s, corresponding to P-guided wave; 2) Select the range where the P-guided wave dispersion energy is located in the dispersion energy spectrum ( Fig.13 a, corresponding to step S04); 3) by keeping the Radon coefficients within the selected target range unchanged and setting the Radon coefficients outside the target range to 0, a target dispersion spectrum is generated (corresponding to step S05); 4) the target dispersion spectrum is inversely transformed to the tx domain to obtain the target seismic record, i.e., the separated P waveguide record (such as Fig.12 5) Subtract the target seismic record from the original seismic record to obtain the seismic record after removing the P waveguide (such as Fig.11 As shown, corresponding to step S07).

[0103] contrast Fig.10 and Fig.11 It can be seen from the seismic records in that after removing the P waveguide using the method of this embodiment, the dispersion wave pattern between the first arrival wave and the direct wave can be effectively suppressed. The separated P waveguide ( Fig.12 ) waveform shows obvious linear dispersion characteristics, namely "broom shape". The dispersion energy spectrum before and after the P-guide wave is removed ( Fig.13 ) can also be seen that after the P-guided wave is removed, there is no multi-mode dispersion energy in the corresponding speed and frequency range, but there is a certain amount of direct wave (marked by the green arrow), refracted wave, reflected wave and multiple reflection (area indicated by the red arrow), which is basically consistent with the above numerical results.

[0104] In order to further analyze the influence of P-guided waves on the actual seismic wave amplitude spectrum, we selected far-offset and near-offset seismic traces with relatively developed and undeveloped P-guided waves, and compared the amplitude spectra before and after the removal of P-guided waves, Scholte waves, and organ pipe waves ( Fig.14 ). Among them, the removal of Scholte waves and organ pipe waves also uses the technical system established in this embodiment. The difference is that it is necessary to select the distribution range of the dispersion energy corresponding to these two waves on the dispersion energy spectrum to establish the corresponding target dispersion energy spectrum. Fig.14(b) shows that after removing the P waveguide, the amplitude of the seismic signal is significantly reduced, and the obvious notch feature at the frequency of 40Hz no longer appears. In the case of near deviation, since the P waveguide has not been fully formed and has weak energy, there is no obvious notch feature in the amplitude spectrum, and the difference before and after the removal of the P waveguide is small; after the low-frequency surface waves and organ pipe waves are removed, the low-frequency information on the amplitude spectrum can be effectively suppressed ( Fig.14 a). These phenomena are basically consistent with the above numerical results, and can be used to illustrate that P-guided waves are an important reason for the obvious notch characteristics in the amplitude spectrum; therefore, removing P-guided waves can provide seismic data with high signal-to-noise ratio for migration imaging of reflection waves.

[0105] The above is a processing method for removing P-guided waves and performing mode separation in marine seismic data provided in one or more embodiments of this specification. Based on the same idea, one or more embodiments of this specification also provide a processing device for removing P-guided waves and performing mode separation in marine seismic data.

[0106] In addition, another embodiment of this embodiment further provides a processing device for removing ocean P-guided waves and separating modes. Fig.15 1 is a schematic structural diagram of the processing device 1500, comprising:

[0107] The dispersion module 1510 is used to determine the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain based on the original seismic records corresponding to the marine seismic gather in the time-space domain.

[0108] The removal module 1520 is used to remove the dispersion energy other than the specified P-waveguide dispersion mode in the dispersion energy spectrum to obtain a target dispersion energy spectrum.

[0109] The inversion module 1530 is used to invert the target dispersion energy spectrum into the time-space domain to obtain the target seismic record corresponding to the specified P-guided wave dispersion mode.

[0110] The processing module 1540 is used to determine the seismic data after removing the P-waveguide dispersion mode based on the original seismic record and the target seismic record.

[0111] The device of this embodiment determines the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain based on the original seismic record corresponding to the marine seismic gather in the time-space domain; then, removes the dispersion energy except the specified P waveguide dispersion mode in the dispersion energy spectrum to obtain the target dispersion energy spectrum, and inverts the target dispersion energy spectrum to the time-space domain to obtain the seismic data corresponding to the target seismic record, that is, the P waveguide dispersion mode; finally, based on the original seismic record and the target seismic record, the seismic data after removing the specified P waveguide dispersion mode can be determined. The seismic data of the specified P waveguide dispersion mode can be used to invert the dispersion curve and waveform of the marine environment with higher accuracy to determine the tomographic data of the longitudinal wave velocity structure of the seabed medium, which can be used as important reference data for exploration and geological survey of marine resources (such as oil, gas, minerals, etc.). In addition, the seismic data after removing the specified P waveguide dispersion mode can be used to analyze the influence of P waveguide on seismic signals and their amplitude spectra, and can provide important denoised seismic data for the offset imaging of reflected waves.

[0112] Optionally, the dispersion module 1510 determines the dispersion energy spectrum corresponding to the marine seismic track gather in the frequency-velocity domain based on the original seismic records corresponding to the marine seismic track gather in the time-space domain, including: performing a high-resolution linear Radon transform on the original seismic records corresponding to the marine seismic track gather in the time-space domain to determine the high-resolution Radon transform coefficients corresponding to the marine seismic track gather in the frequency-slowness domain; mapping the high-resolution Radon transform coefficients corresponding to the marine seismic track gather in the frequency-slowness domain to the frequency-velocity domain to perform dispersion energy spectrum imaging to obtain the dispersion energy spectrum corresponding to the marine seismic track gather in the frequency-velocity domain.

[0113] Optionally, the dispersion module 1510 performs a high-resolution linear Radon transform on the original seismic record corresponding to the marine seismic gather in the time-space domain to determine the high-resolution Radon transform coefficient corresponding to the marine seismic gather in the frequency-slowness domain, including: for each single-frequency seismic data in the original seismic record, constructing a high-resolution Radon coefficient calculation formula corresponding to the frequency-slowness domain: Where I represents the identity matrix; W m W represents the weighting matrix of Radon transform coefficients; d represents the weighted matrix of seismic data; L represents the forward transformation operator; λ represents the damping factor; d represents the two-dimensional matrix of single-frequency seismic data; m represents the two-dimensional matrix of Radon coefficients; for each single-frequency seismic data, W in the high-resolution Radon transformation coefficient calculation formula is calculated based on the conjugate gradient algorithm. m and W dIteration is performed to determine the Radon transform coefficient corresponding to each of the single-frequency seismic data in the frequency-slowness domain; the Radon transform coefficient of each of the single-frequency seismic data is arranged in frequency order to obtain the Radon transform coefficient corresponding to the marine seismic gather in the frequency-slowness domain.

[0114] Optionally, the dispersion module 1510 performs a conjugate gradient algorithm on W in the high-resolution Radon transform coefficient calculation formula for each single-frequency seismic data. m and W d Iteration is performed to determine the Radon transform coefficient corresponding to each single-frequency seismic data in the frequency-slowness domain, including:

[0115] For each single-frequency seismic data, multiple rounds of iterations are performed:

[0116] Based on the formula diag(W m ) j =|m j | 1 / 2 Update W m , and based on the formula diag(W d ) j =|r j | 1 / 2 Update W d ; where j represents the current iteration number; m j is the Radon transform coefficient obtained in the jth iteration; r j is the standard deviation of the residual;

[0117] Based on the formula and formula Calculate variable KM j and variable y; where M j represents the coefficient of the jth iteration; M j-1 represents the coefficient of the j-1th iteration;

[0118] Solve the linear equation KM using the conjugate gradient algorithm j = the root of y, and obtain the coefficient M of the jth iteration j

[0119] Based on the formula Calculate the high-resolution Radon transform coefficients m for the jth iteration j .

[0120] Optionally, the dispersion module 1510 maps the high-resolution Radon transform coefficients to the frequency-velocity domain for dispersion energy spectrum imaging to obtain the dispersion energy spectrum corresponding to the marine seismic track set in the frequency-velocity domain, including: based on the mathematical relationship between velocity and slowness, mapping the high-resolution Radon transform coefficients to the frequency-velocity domain for dispersion energy spectrum imaging to obtain the dispersion energy spectrum corresponding to the marine seismic track set in the frequency-velocity domain.

[0121] Optionally, the removal module 1520 determines a target dispersion energy spectrum based on the dispersion energy spectrum corresponding to the marine seismic data set in the frequency-velocity domain, including: selecting a range of dispersion energy of a specified P-guide wave dispersion mode in the dispersion energy spectrum corresponding to the frequency-velocity domain, and setting the dispersion energy values ​​outside the range to zero to obtain a target dispersion energy spectrum.

[0122] Optionally, after obtaining the seismic data corresponding to the specified P-waveguide dispersion mode based on the target dispersion energy spectrum, the inversion module 1530 is also used to invert the dispersion curve and waveform based on the seismic data of the specified P-waveguide mode to obtain the tomographic data of the longitudinal wave velocity structure of the seabed medium corresponding to the marine seismic track set.

[0123] Optionally, the processing module 1540 determines the seismic data after removing the specified P waveguide dispersion mode based on the original seismic record and the target seismic record, including: eliminating the target seismic record from the original seismic record to determine the seismic data after removing the specified P waveguide dispersion mode.

[0124] In addition, the processing device of this embodiment further includes:

[0125] An analysis module is used to: perform dispersion curve and waveform inversion based on the seismic data of the specified P-waveguide dispersion mode to determine the tomographic data of the longitudinal wave velocity structure of the seabed medium corresponding to the marine seismic track set; and / or, based on the seismic data after removing the specified P-waveguide dispersion mode, analyze the influence of P-waveguide on the seismic signal and its amplitude spectrum to determine the denoised seismic data used for offset imaging of the reflected wave.

[0126] It should be noted that the processing device of this embodiment can be used as Figure 1 The execution subject of the method shown can thus realize Figure 1 The steps and functions in the method shown.

[0127] Fig.16 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Fig.16At the hardware level, the electronic device includes a processor, and optionally also includes an internal bus, a network interface, and a memory. The memory may include a memory, such as a high-speed random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage. Of course, the electronic device may also include hardware required for other services.

[0128] The processor, network interface and memory can be interconnected through an internal bus, which can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.15 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0129] The memory is used to store the computer program. Specifically, the computer program may include a program code, and the program code includes a computer operation instruction. The memory may include a memory and a non-volatile memory, and provides the computer program to the processor.

[0130] The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it, forming the above-mentioned Fig.15 The processing device for removing ocean P-guided waves and separating modes is shown. Correspondingly, the processor executes the program stored in the memory and is specifically used to perform the following operations:

[0131] Based on the original seismic records corresponding to the marine seismic gather in the time-space domain, the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain is determined.

[0132] The dispersion energy other than the specified P-waveguide dispersion mode in the dispersion energy spectrum is removed to obtain a target dispersion energy spectrum.

[0133] The target dispersion energy spectrum is inverted to the time-space domain to obtain the target seismic record corresponding to the specified P-guided wave dispersion mode.

[0134] Based on the original seismic record and the target seismic record, seismic data after removing the P-waveguide dispersion mode is determined.

[0135] The above is as in this manual Figure 1 The communication encryption control method disclosed in the illustrated embodiment can be applied to a processor and implemented by the processor. The processor may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiments of the present application can be directly embodied as a hardware decoding processor for execution, or a combination of hardware and software modules in the decoding processor for execution. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0136] Of course, in addition to software implementation, the electronic device of this specification does not exclude other implementation methods, such as logic devices or a combination of software and hardware, etc., that is to say, the execution subject of the following processing flow is not limited to each logic unit, but can also be hardware or logic devices.

[0137] In addition, an embodiment of the present application also proposes a computer-readable storage medium, which stores one or more computer programs, and the one or more computer programs include instructions.

[0138] When the above instructions are executed by a portable electronic device including multiple application programs, the portable electronic device can execute Figure 1 The steps in the method shown include:

[0139] Based on the original seismic records corresponding to the marine seismic gather in the time-space domain, the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain is determined.

[0140] The dispersion energy other than the specified P-waveguide dispersion mode in the dispersion energy spectrum is removed to obtain a target dispersion energy spectrum.

[0141] The target dispersion energy spectrum is inverted to the time-space domain to obtain the target seismic record corresponding to the specified P-guided wave dispersion mode.

[0142] Based on the original seismic record and the target seismic record, seismic data after removing the P-waveguide dispersion mode is determined.

[0143] Those skilled in the art will appreciate that the embodiments of this specification may be provided as methods, systems or computer program products. Therefore, this specification may take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, this specification may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0144] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0145] The above are only embodiments of this specification and are not intended to limit this specification. For those skilled in the art, this specification may be subject to various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this specification shall be included in the scope of the claims of this specification. In addition, all other embodiments obtained by ordinary technicians in this field without creative work shall fall within the scope of protection of this document.

Claims

1. A processing method for ocean P-guided wave removal and mode separation, characterized in that: include: Based on the original seismic records corresponding to the marine seismic gathers in the time-space domain, determining the dispersion energy spectrum corresponding to the marine seismic gathers in the frequency-velocity domain; Removing the dispersion energy other than the specified P-waveguide dispersion mode in the dispersion energy spectrum to obtain a target dispersion energy spectrum; Inverting the target dispersion energy spectrum to the time-space domain to obtain a target seismic record corresponding to the specified P waveguide dispersion mode; Based on the original seismic record and the target seismic record, seismic data after removing the P-waveguide dispersion mode is determined.

2. The method according to claim 1, characterized in that Based on the original seismic records corresponding to the marine seismic gathers in the time-space domain, determining the dispersion energy spectrum corresponding to the marine seismic gathers in the frequency-velocity domain, including: Performing a high-resolution linear Radon transform on the original seismic records corresponding to the marine seismic gather in the time-space domain, and determining the high-resolution Radon transform coefficients corresponding to the marine seismic gather in the frequency-slowness domain; The high-resolution Radon transform coefficients corresponding to the marine seismic gather in the frequency-slowness domain are mapped to the frequency-velocity domain for dispersion spectrum imaging, and the dispersion spectrum corresponding to the marine seismic gather in the frequency-velocity domain is obtained.

3. The method according to claim 1, characterized in that Performing a high-resolution linear Radon transform on the original seismic records corresponding to the marine seismic gather in the time-space domain, and determining the high-resolution Radon transform coefficients corresponding to the marine seismic gather in the frequency-slowness domain, including: For each single-frequency seismic data in the original seismic record, a high-resolution Radon transform coefficient calculation formula corresponding to the frequency-slowness domain is constructed: Where I represents the identity matrix; W m W represents the weighting matrix of Radon transform coefficients; d represents the weighted matrix of seismic data; L represents the forward transformation operator; λ represents the damping factor; d represents the two-dimensional matrix of single-frequency seismic data; m represents the two-dimensional matrix of Radon coefficients; For each single-frequency seismic data, the W in the high-resolution Radon transform coefficient calculation formula is calculated based on the conjugate gradient algorithm. m and W d Iterate to determine the high-resolution Radon transform coefficient corresponding to each single-frequency seismic data in the frequency-slowness domain; The high-resolution Radon transform coefficients of each single-frequency seismic data are arranged in frequency order to obtain the high-resolution Radon transform coefficients corresponding to the marine seismic gather in the frequency-slowness domain.

4. The method according to claim 3, characterized in that For each single-frequency seismic data, the W in the high-resolution Radon transform coefficient calculation formula is calculated based on the conjugate gradient algorithm. m and W d Iteration is performed to determine the high-resolution Radon transform coefficient corresponding to each single-frequency seismic data in the frequency-slowness domain, including: For each single-frequency seismic data, multiple rounds of iterations are performed: Based on the formula diag(W m ) j =|m j | 1 / 2 Update W m , and based on the formula diag(W d ) j =|r j | 1 / 2 Update W d ; where j represents the current iteration number; m j is the high-resolution Radon transform coefficient obtained in the jth iteration; r j is the standard deviation of the residual; Based on the formula and formula Calculate variable KM j and variable y; where M j represents the coefficient of the jth iteration; M j-1 represents the coefficient of the j-1th iteration; Solve the linear equation KM using the conjugate gradient algorithm j = the root of y, and obtain the coefficient M of the jth iteration j Based on the formula Calculate the high-resolution Radon transform coefficient vector m for the jth iteration j .

5. The method according to claim 2, characterized in that: Mapping the high-resolution Radon transform coefficients in the frequency-slowness domain to the frequency-velocity domain for dispersion spectrum imaging, and obtaining the dispersion spectrum corresponding to the marine seismic gather in the frequency-velocity domain, including: Based on the mathematical relationship between velocity and slowness, the high-resolution Radon transform coefficients in the frequency-slowness domain are mapped to the frequency-velocity domain for dispersion energy spectrum imaging, and the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain is obtained.

6. The method according to claim 1, characterized in that Removing the dispersion energy outside the specified P waveguide dispersion mode in the dispersion energy spectrum to obtain a target dispersion energy spectrum, including: The range where the dispersion energy of the designated P-waveguide dispersion mode is located is selected from the dispersion energy spectrum corresponding to the frequency-velocity domain, and the dispersion energy values ​​outside the range are set to zero to obtain the target dispersion energy spectrum.

7. The method according to claim 6, characterized in that The designated P-waveguide dispersion mode is one or at least two.

8. The method according to claim 1, characterized in that Based on the original seismic record and the target seismic record, determining seismic data after removing the specified P guided wave dispersion mode, comprising: The target seismic record is eliminated from the original seismic record to determine seismic data after the specified P waveguide dispersion mode is removed.

9. The method according to claim 1, characterized in that: Also includes: Performing dispersion curve and waveform inversion based on the seismic data of the specified P-guided wave dispersion mode to determine tomographic data of the P-wave velocity structure of the seafloor medium corresponding to the marine seismic gather; and / or, Based on the seismic data after removing the specified P-waveguide dispersion mode, the influence of the P-waveguide on the seismic signal and its amplitude spectrum is analyzed to determine the denoised seismic data for migration imaging of the reflection wave.

10. A processing device for ocean P-guided wave removal and mode separation, characterized in that: include: A dispersion module, used to determine the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain based on the original seismic records corresponding to the marine seismic gather in the time-space domain; A removal module, used to remove the dispersion energy other than the specified P-guided wave dispersion mode in the dispersion energy spectrum to obtain a target dispersion energy spectrum; An inversion module, used for inverting the target dispersion energy spectrum to the time-space domain to obtain a target seismic record corresponding to the specified P waveguide dispersion mode; A processing module is used to determine the seismic data after removing the P-guide wave dispersion mode based on the original seismic record and the target seismic record.

11. An electronic device, comprising a processor; and a memory configured to store computer executable instructions, wherein when the computer executable instructions are executed, the processor executes the method according to any one of claims 1 to 10.

12. A computer-readable storage medium, wherein the computer-readable storage medium is used to store computer-executable instructions, wherein the computer-executable instructions implement the method according to any one of claims 1 to 10 when executed by a processor.

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