A processing method and device for ocean P-wave removal and mode separation

Abstract

The application provides a processing method and device for ocean P-wave removal and mode separation. The method comprises the following steps: determining a dispersion energy spectrum corresponding to a marine seismic gather in a frequency-velocity domain based on an original seismic record corresponding to the marine seismic gather in a time-space domain; removing dispersion energy in the dispersion energy spectrum except for a specified P-wave dispersion mode to obtain a target dispersion energy spectrum; inversely transforming the target dispersion energy spectrum to the time-space domain to obtain a target seismic record corresponding to the specified P-wave dispersion mode; and determining seismic data after removal of the P-wave dispersion mode based on the original seismic record and the target seismic record. The extracted P-wave seismic data is used for inversion of dispersion curves and waveforms to realize high-precision detection of a seabed P-wave velocity structure or marine geological survey; and the seismic data after removal of the P-wave dispersion mode is used for analysis of the influence of the P-wave on a seismic signal and an amplitude spectrum thereof, and provides denoised seismic data for migration imaging of reflected waves.

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

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

[0003] Since the discovery of P guided wave, scholars in the fields of natural earthquake and exploration earthquake have studied it from theoretical derivation and data processing and analysis. Among them, more are based on the dispersion inversion of P guided wave data to tomographically predict the V P However, the research on P guided wave removal and dispersion mode separation is relatively less. Nowadays, more and more seismic exploration operations are carried out in marine environment, and it is particularly important to develop the technology of marine P guided wave removal and dispersion mode separation. This is mainly because: 1) Extracting pure P guided wave record or record of a or multiple order dispersion mode will not be disturbed by other wave types, which is beneficial to obtain higher quality dispersion spectrum and improve the inversion accuracy of dispersion curve. Moreover, extracting pure P guided wave seismic wave type is also beneficial to the waveform inversion of corresponding wave field; 2) P guided wave 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 record.

[0004] Therefore, how to extract and remove the seismic data of P guided wave dispersion mode in the special scene of marine environment is the technical problem to be solved by the present application. SUMMARY

[0005] The present application aims to provide a processing method and device for marine P guided wave removal and mode separation, which can extract and remove the seismic data of P guided wave dispersion mode from the collected original seismic traces in the special scene of marine environment.

[0006] In order to achieve the above-mentioned purpose, the embodiments of the present application are implemented as follows:

[0007] In a first aspect, a processing method for P-wave removal and mode separation of marine seismic data is provided, comprising:

[0008] determining a dispersion spectrum corresponding to the marine seismic data in a frequency-velocity domain based on original seismic records corresponding to the marine seismic data in a time-space domain;

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

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

[0011] determining seismic data after removal of the P-wave dispersion mode based on the original seismic record and the target seismic record.

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

[0013] a dispersion module configured to determine a dispersion spectrum corresponding to the marine seismic data in a frequency-velocity domain based on original seismic records corresponding to the marine seismic data in a time-space domain;

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

[0015] an inversion module configured to invert the target dispersion spectrum to the time-space domain to obtain a target seismic record corresponding to the specified P-wave dispersion mode;

[0016] a processing module configured to determine seismic data after removal of the P-wave dispersion mode based on the original seismic record and the target seismic record.

[0017] In a third aspect, an electronic device is provided, comprising: a processor; and a memory configured to store computer executable instructions, which, when executed, cause the processor to perform the method of the first aspect.

[0018] In a fourth aspect, a computer readable storage medium is provided, which is configured to store computer executable instructions, which, when executed by a processor, implement the method of the first aspect.

[0019] The embodiment of the application 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-wave dispersion mode in the dispersion energy spectrum to obtain the target dispersion energy spectrum, and inversely transforms the target dispersion energy spectrum to the time-space domain to obtain the target seismic record, i.e., the seismic data corresponding to the P-wave dispersion mode; finally, based on the original seismic record and the target seismic record, the seismic data after removing the specified P-wave dispersion mode can be determined. The seismic data of the specified P-wave dispersion mode can be used for higher-precision inversion of the dispersion curve and waveform of the marine environment to determine the tomographic data of the P-wave velocity structure of the seabed medium, which can be used as important reference data for marine resource (such as oil and gas, mineral resources, etc.) exploration and geological survey, etc. In addition, the seismic data after removing the specified P-wave dispersion mode can be used for analyzing the influence of the P-wave on the seismic signal and its amplitude spectrum, and can provide important denoised seismic data for the migration imaging of the reflected wave. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0021] Figure 1 The first flowchart of the processing method of the marine seismic gather of the embodiment of the application.

[0022] Figure 2 The second flowchart of the processing method of the marine seismic gather of the embodiment of the application.

[0023] Figure 3 The flowchart of the iterative calculation of the high-resolution Radon transform coefficient by using the conjugate gradient algorithm.

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

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

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

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

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

[0029] Figure 9 is a schematic diagram of the single-channel seismic record before and after the model data removes the P-wave, and the amplitude spectrum comparison thereof;

[0030] Figure 10 is a schematic diagram of the measured OBN common receiver gather;

[0031] Figure 11 is a schematic diagram of the seismic record after the measured data removes the P-wave;

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

[0033] Figure 13 is a schematic diagram of the dispersion spectrum comparison before and after the measured data removes the P-wave;

[0034] Figure 14 is a schematic diagram of the single-channel seismic record amplitude spectrum comparison before and after the measured data removes the P-wave;

[0035] Figure 15 is a schematic diagram of the structure of the marine seismic gather processing device according to an embodiment of the present application.

[0036] Figure 16 is a schematic diagram of the structure of the 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 the present specification, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present specification, rather than all the embodiments. Based on the embodiments in the present specification, all other embodiments obtained by those skilled in the art without creative labor should fall within the protection scope of the present specification.

[0038] One embodiment of the present application proposes a processing method for marine P-wave removal and mode separation. Figure 1 is a schematic diagram of the flow of the processing method, including the following steps:

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

[0040] In this step, the high-resolution linear Radon transform (HLRT) is performed on the original primary seismic record corresponding to the marine seismic gather in the time-space (t-x) domain to determine the high-resolution Radon transform coefficient corresponding to the marine seismic gather in the frequency-slowness (f-p) domain; then, the high-resolution Radon transform coefficient corresponding to the marine seismic gather in the frequency-slowness domain is mapped to the frequency-velocity (f-v) domain for dispersion spectrum imaging to obtain the dispersion spectrum corresponding to the marine seismic gather in the frequency-velocity domain.

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

[0042] After the Fourier forward transform is performed on each trace in the two-dimensional t-x domain marine seismic gather d(t, x) 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 is as follows:

[0045]

[0046] wherein 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 express formula (1) and formula (2) in the form of a matrix as follows:

[0047] d = Lm, (3)

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

[0049] wherein L = e i2πfpx is the forward transform operator of the linear Radon transform; d represents the two-dimensional matrix of single-frequency seismic data; and 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, and m adj is a low-resolution Radon matrix expressed by using the transpose or adjoint operator. For the solution of formula (3), the objective function J needs to be minimized.

[0050] J = ‖d - Lm‖ 2 (5)

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

[0052] m = (L T L + λI) -1 L T d, (6)

[0053] At this time, the Radon transform is essentially a standard Radon transform, and the obtained Radon transform coefficient is a least square solution, and the resolution of the dispersion energy is not high. Therefore, on this basis, for the model (dispersion energy) that can best fit the data, an iterative reweighted conjugate gradient (IRCG) algorithm is used to calculate the high-resolution Radon transform coefficient. Through this pre-weighting, a sparse solution can be obtained, and thus the low resolution of the dispersion energy and spatial false frequency caused by insufficient wave field information can be reduced; in this case, the high-resolution Radon transform coefficient can be solved by the following formula:

[0054]

[0055] Where I represents the unit matrix; W m represents the weighting matrix of the Radon transform coefficient; W d represents the weighting matrix of the seismic data.

[0056] When the jth IRCG iteration calculation is performed, 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] Where m j is the Radon transform coefficient obtained in the jth iteration; r j is the standard deviation of the residual,

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

[0061] ​1. Fourier transform the 2D t-x domain seismic data along the time axis to extract the single frequency slice of the seismic data at each frequency;

[0062] 2. Set the initial damping factor λ, the maximum iteration number Num, and 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 . Calculate the least square solution M0 in the frequency domain according to formula (6) first, and set M0 = W m m0 as the initial solution;

[0064] 4. Start the iterative calculation: when the iteration variable j <= Num, perform the following calculation process:

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

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

[0067] ③ Solve the root of the linear equation KM j = y by using the conjugate gradient algorithm to obtain the coefficient M j of the jth iteration;

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

[0069] 5. Perform the calculation of all the single frequency slices according to the above steps, and arrange them in the order of frequency to obtain the Radon transform coefficient of the seismic data in the f-p domain. Based on the mathematical relationship between velocity and slowness (v = 1 / p), the Radon transform coefficient can be mapped into the f-v domain for dispersion energy spectrum imaging (modulus, normalization and imaging processing of the Radon transform coefficient), so as to obtain the dispersion energy spectrum of the marine seismic trace set in the f-v domain.

[0070] S104. Remove the dispersion energy of the dispersion energy spectrum except the specified P wave dispersion mode to obtain the target dispersion energy spectrum.

[0071] This step selects the range of the dispersion energy of the specified P wave dispersion mode in the dispersion energy spectrum corresponding to the frequency-velocity domain, and sets the dispersion energy values outside the range to zero to obtain the target dispersion energy spectrum.

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

[0073] S106, inverse transform the target dispersion energy spectrum to the time-space domain to obtain a target seismic record corresponding to the specified P-wave dispersion mode.

[0074] This step inversely transforms the f-v domain target dispersion energy spectrum to the t-x domain to obtain a target seismic record. It should be understood that if the P-wave is to be removed, the target seismic record is the entire P-wave record; if a certain dispersion mode of the P-wave is to be separated, the target seismic record is the seismic record of the mode.

[0075] The extracted seismic data corresponding to the specified P-wave dispersion mode can be used to perform tomographic imaging of the P-wave velocity structure of the seabed medium in the marine environment. For example, dispersion curve and waveform inversion can be performed based on the seismic data corresponding to the specified P-wave mode to obtain tomographic data of the P-wave velocity structure of the seabed medium corresponding to the marine seismic trace set. It should be noted that dispersion curve and waveform inversion based on P-wave seismic data is a prior art, which will not be described here.

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

[0077] This step removes the target seismic record from the original seismic record to obtain the seismic data after removing the specified P-wave dispersion mode.

[0078] The seismic data after removing the specified P-wave dispersion mode can be used to analyze the influence of the P-wave on the seismic signal and its amplitude spectrum, and can provide important denoised seismic data for migration imaging of reflected waves.

[0079] In summary, the method of the 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-wave dispersion mode in the dispersion energy spectrum to obtain the target dispersion energy spectrum, and inversely transforms the target dispersion energy spectrum to the time-space domain to obtain the target seismic record; finally, determines the seismic data after removing the specified P-wave dispersion mode based on the original seismic record and the target seismic record. The seismic data corresponding to the specified P-wave dispersion mode can be used to perform inversion on the marine environment in higher precision of the dispersion curve and the waveform to determine the tomographic data of the P-wave velocity structure of the seabed medium, which can be used as important reference data in aspects of marine resource (such as oil and gas, mineral resources and the like) exploration and geological survey. In addition, the seismic data after removing the specified P-wave dispersion mode can be used to analyze the influence of the P-wave on the seismic signal and the amplitude spectrum thereof, and can provide important seismic data after denoising for the migration imaging of the reflected wave.

[0080] The method of the embodiment will be introduced below in combination with an actual application scenario.

[0081] The flow of the application scenario is as shown in the figure, mainly including the following steps: Figure 2

[0082] S01: input the original seismic data (multi-channel seismic record);

[0083] S02: perform high-resolution linear Radon transformation on the t-x domain seismic record to calculate the high-resolution Radon domain transformation coefficient;

[0084] S03: map the high-resolution Radon transformation coefficient to the f-v domain to generate the f-v domain dispersion energy spectrum image;

[0085] S04: select the range of the target wave field on the f-v domain dispersion energy spectrum;

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

[0087] S06: inversely transform the target dispersion energy spectrum to the t-x domain to obtain the target seismic record;

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

[0089] S08: output the 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 the embodiment, the model data is used to test the application scenario.

[0091] ​Table 1 shows a two-dimensional (2D) shallow sea layered medium model set up based on 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) earthquake record shown in FIG. 2 is a three-dimensional three-component (2D-3C) earthquake record (the above work corresponds to step S01). Figure 3 The process in Calculate high-resolution Radon transform coefficients and generate Figure 5 The fv domain dispersion energy spectrum image is shown (the above work corresponds to steps S02 to S03). In order to accurately determine the distribution characteristics and range of the ocean P-wave on the dispersion energy spectrum, the theoretical dispersion curves of various dispersion wave types in the ocean environment, including: P-wave (Guided-P 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 energy spectrum ( Figure 5 d~f). As can be seen from the figure, P-wave has multi-order dispersion modes, and its dispersion energy is mainly distributed in the speed range from the seawater layer P-wave velocity to the maximum solid P-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-wave in the seismic data is removed. The specific removal method is as follows: 1) First, select the range where the P-wave dispersion energy is located in the fv domain dispersion energy spectrum ( Figure 6 The red dotted box in a corresponds to step S04); 2) the target dispersion energy spectrum is generated by keeping the Radon coefficient within the selected target range unchanged and setting the Radon coefficient outside the target range to 0 (corresponding to step S05); 3) the target dispersion energy spectrum is inversely transformed into the tx domain to obtain the target seismic record, that is, the separated P waveguide record (as shown in FIG. 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 guided wave (as shown in FIG. Figure 8b shows, corresponding to step S07). It is worth noting that if a certain order of dispersion mode of P guided wave is to be separated, only the dispersion energy of the mode needs to be selected in step S04, and then steps S05-S07 are performed; since these operations are basically the same as the above, they will not be described in detail here.

[0099] Figure 6 b shows the dispersion energy spectrum of the seismic record after removing the P guided wave, and the dispersion energy spectrum of the original seismic record Figure 6 a) can be seen: 1) After removing the P guided wave, there is no longer multi-mode dispersion energy in the corresponding velocity and frequency range, but there is certain direct wave (green arrow marked), refracted wave, reflected wave and multiple reflection (red arrow indicating area) energy. To verify the accuracy of the above result, the seismic wave field under the condition of sea surface as an absorbing boundary condition is also simulated, and the P guided wave will not be generated. Figure 7 shows the dispersion energy spectrum in this case; obvious direct wave, refracted wave and reflected wave energy can be seen in the corresponding area, which is similar to Figure 6 (b). The difference is the lack of multiple wave energy; 2) After removing the P guided wave, the energy of the body wave is highlighted, so that Figure 6 the dispersion energy of the surface wave and the organ pipe leakage mode in (b) is relatively weak.

[0100] Figure 8 respectively show the seismic record before and after removing the P guided wave and the removed P guided wave record. As can be seen from the figure: 1) When the P guided wave is removed, the seismic record can directly show the direct wave, refracted wave and some reflected wave and multiple reflection events; 2) Due to the lack of P guided wave strong energy masking, the seismic record is visually clearer Figure 8 (b) than Figure 8 (a). In order to intuitively understand the influence of the P guided wave on other seismic signals, the single-channel seismic record before and after removing the P guided wave and its amplitude spectrum are compared in Figure 9 . The comparison result shows that when the P guided wave is removed, the dispersion waveform characteristics are obviously weakened, the amplitude of the seismic signal is obviously reduced, especially in the high frequency range; this is because the P guided wave is coupled by multiple reflections and refracted P waves "trapped" in the water layer, which can carry a large amount of seismic energy. In addition, by comparing the amplitude spectrum before and after removing the P guided wave, it can be found that when the P guided wave is removed, the significant notch characteristics appearing on the amplitude spectrum are weakened.

[0101] Further, in order to test the practicability of the method of the embodiment, the 4C-OBN data collected in the Chengdao shallow water area can be tested for P guided wave removal according to the model data test process. The data test is still taken as an example.

[0102] Figure 10 The display shows the common detection point gather of a certain OBN. It can be seen that there are significant P-guided waves in the seismic record, which is consistent with the model data. The P-guided wave removal of the measured data is still based on Figure 2 The technical process shown in the figure is as follows: 1) Input the original earthquake record ( Figure 10 , corresponding to step S01), and generate the dispersion energy spectrum of the seismic record in the fv domain using high-resolution linear Radon transform ( Figure 13 a, corresponding to steps S02 to S03). Multi-order dispersion energy can be observed in the phase velocity range > 1500m / s in the dispersion energy spectrum, corresponding to P-guided wave; 2) Select the range where the P-guided wave dispersion energy is located in the dispersion energy spectrum ( Figure 13 3) Generate a target dispersion energy spectrum by keeping the Radon coefficient within the selected target range unchanged and setting the Radon coefficient outside the target range to 0 (corresponding to step S05); 4) Inverse transform the target dispersion energy spectrum into the tx domain to obtain the target seismic record, that is, the separated P waveguide record (as shown in the red dotted box in a). Figure 12 5) Subtract the target seismic record from the original seismic record to obtain the seismic record after removing the P waveguide (as shown in step S06); Figure 11 As shown, corresponding to step S07).

[0103] contrast Figure 10 and Figure 11 It can be seen from the seismic records in the example that after removing the P-guided wave by the method of this embodiment, the dispersion wave pattern between the first arrival wave and the direct wave is effectively suppressed. Figure 12 ) waveform shows obvious linear dispersion characteristics, namely "broom shape". The dispersion energy spectrum before and after the P waveguide is removed ( Figure 13 ) can also be seen that after the P-guided wave is removed, there is no more multi-mode dispersion energy in the corresponding speed and frequency range. Instead, 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] 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 where P-guided waves are relatively developed and undeveloped, and compared the amplitude spectra before and after the removal of P-guided waves, Scholte waves, and organ pipe waves ( Figure 14 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. Figure 14(b) The amplitude of the seismic signal is significantly reduced after the P-wave is removed, and the obvious notch feature at 40 Hz disappears. For the near-offset case, the P-wave has not been fully formed and the energy is weak, so there is no obvious notch feature on the amplitude spectrum, and the difference before and after the P-wave is removed is small. After the removal of low-frequency surface waves and organ pipe waves, the low-frequency information on the amplitude spectrum can be effectively suppressed. Figure 14 a) These phenomena are basically consistent with the numerical results described above, and can be used to explain that the P-wave is an important reason for the obvious notch feature on the amplitude spectrum. Therefore, the removal of the P-wave can provide seismic data with high signal-to-noise ratio for reflection wave migration imaging.

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

[0106] In addition, another embodiment of the present embodiment also provides a processing device for P-wave removal and mode separation in marine seismic data, Figure 15 is a structural schematic diagram of the processing device 1500, which includes:

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

[0108] The removal module 1520 is configured to remove dispersion energy in the dispersion energy spectrum except for a specified P-wave dispersion mode, to obtain a target dispersion energy spectrum.

[0109] The inverse transformation module 1530 is configured to inversely transform the target dispersion energy spectrum to the time-space domain, to obtain a target seismic record corresponding to the specified P-wave dispersion mode.

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

[0111] The device of the embodiment is based on the original seismic record corresponding to the marine seismic gather in the time-space domain, determines the dispersion spectrum corresponding to the marine seismic gather in the frequency-velocity domain, then removes the dispersion energy in the dispersion spectrum except for the specified P-wave dispersion mode to obtain the target dispersion spectrum, and inversely transforms the target dispersion spectrum to the time-space domain to obtain the target seismic record, i.e., the seismic data corresponding to the P-wave dispersion mode. Finally, based on the original seismic record and the target seismic record, the seismic data after removing the specified P-wave dispersion mode can be determined. The seismic data of the specified P-wave dispersion mode can be used for higher-precision inversion of the dispersion curve and waveform of the marine environment to determine the tomographic data of the P-wave velocity structure of the seabed medium, which can be used as important reference data for marine resource (such as oil and gas, mineral resources, etc.) exploration and geological survey, etc. In addition, the seismic data after removing the specified P-wave dispersion mode can be used to analyze the influence of P-wave on the seismic signal and its amplitude spectrum, and can provide important denoised seismic data for reflection wave migration imaging.

[0112] Optionally, the dispersion module 1510 determines the dispersion 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, including: performing high-resolution linear Radon transformation on the original seismic record corresponding to the marine seismic gather in the time-space domain to determine the high-resolution Radon transformation coefficient corresponding to the marine seismic gather in the frequency-slowness domain; and mapping the high-resolution Radon transformation coefficient corresponding to the marine seismic gather in the frequency-slowness domain to the frequency-velocity domain for dispersion spectrum imaging to obtain the dispersion spectrum corresponding to the marine seismic gather in the frequency-velocity domain.

[0113] Optionally, the dispersion module 1510 performs high-resolution linear Radon transformation on the original seismic record corresponding to the marine seismic gather in the time-space domain to determine the high-resolution Radon transformation 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: wherein I represents a unit matrix; W m represents a weighting matrix of the Radon transformation coefficient; W d represents a weighting matrix of the seismic data; L represents a forward transformation operator; λ represents a damping factor; d represents a two-dimensional matrix of the single-frequency seismic data; m represents a two-dimensional matrix of the Radon coefficient; for each single-frequency seismic data, based on the conjugate gradient algorithm, W m and W diterating to determine a Radon transform coefficient corresponding to each of the single-frequency seismic data in the frequency-slowness domain; and arranging the Radon transform coefficient of each of the single-frequency seismic data in a frequency order to obtain a Radon transform coefficient corresponding to the marine seismic gather in the frequency-slowness domain.

[0114] Optionally, the dispersion module 1510 calculates W m and W d based on a conjugate gradient algorithm for each of the single-frequency seismic data.

[0115] For each of the single-frequency seismic data, a plurality of iterations are performed.

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

[0117] Based on a formula and a formula , a variable KM j and a variable y are calculated; wherein M j represents a coefficient in the jth iteration round; M j-1 represents a coefficient in the (j-1)th iteration round.

[0118] A root of a linear equation KM j =y is solved by using a conjugate gradient algorithm to obtain the coefficient M j

[0119] Based on a formula , a high-resolution Radon transform coefficient m j in the jth iteration round is calculated.

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

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

[0122] Optionally, the inverse module 1530, after obtaining the seismic data corresponding to the specified P-wave dispersion mode based on the target dispersion spectrum, is further configured to perform dispersion curve and waveform inversion based on the seismic data of the specified P-wave mode to obtain tomographic data of the P-wave velocity structure of the seabed medium corresponding to the marine seismic gather.

[0123] Optionally, the processing module 1540 determines the seismic data after removing the specified P-wave dispersion mode based on the original seismic record and the target seismic record, including: performing rejection of the original seismic record with respect to the target seismic record to determine the seismic data after removing the specified P-wave dispersion mode.

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

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

[0126] It should be noted that the processing device of the embodiment can serve as Figure 1 the execution subject of the method shown in Figure 1 and thus can implement the steps and functions in the method shown in

[0127] Figure 16 is a structural schematic diagram of an electronic device provided by an embodiment of the present application. Please refer to Figure 16At the hardware level, the electronic device includes a processor, and optionally further includes an internal bus, a network interface, and a memory. The memory can include a memory such as a random-access memory (RAM), and can further include a non-volatile memory such as at least one disk memory. Of course, the electronic device can further include other hardware required by a business.

[0128] The processor, the network interface, and the memory can be connected to each other through the internal bus, which can be an industry standard architecture (ISA) bus, a peripheral component interconnect (PCI) bus, an extended industry standard architecture (EISA) bus, or the like. The bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, Figure 15 Only one bidirectional arrow is used in the figure, but it does not mean that there is only one bus or only one type of bus.

[0129] The memory is used to store a computer program. Specifically, the computer program can include program code including computer operation instructions. The memory can include a memory and a non-volatile memory, and provide 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, and forms the above-mentioned Figure 15 The processing device for removing P-wave and mode separation in the ocean shown in the figure. 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 record corresponding to the marine seismic trace set in the time-space domain, the frequency-velocity domain dispersion energy spectrum corresponding to the marine seismic trace set is determined.

[0132] Remove the dispersion energy in the dispersion energy spectrum except the specified P-wave dispersion mode to obtain the target dispersion energy spectrum.

[0133] Inverse transform the target dispersion energy spectrum to the time-space domain to obtain the target seismic record corresponding to the specified P-wave dispersion mode.

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

[0135] The above as described in the specificationFigure 1 The communication encryption control method disclosed in the embodiments can be applied to a processor and implemented by the processor. The processor can be an integrated circuit chip with processing capability. In implementation, the steps of the method can be completed by hardware integrated logic circuits in the processor or by instructions in the form of software. The 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 gate 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 by the processor. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as a hardware code processor for execution, or a combination of hardware and software modules in the code processor for execution. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, or other mature storage media in the art. The storage medium is located in the storage memory, and the processor reads information in the storage memory and combines the hardware to complete the steps of the above method.

[0136] Of course, in addition to the software implementation, the electronic device of the present application does not exclude other implementation manners, such as logic devices or a combination of software and hardware, etc. That is, 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, the present application also provides a computer readable storage medium, which stores one or more computer programs, and the one or more computer programs include instructions.

[0138] The above instructions, when executed by the portable electronic device including a plurality of application programs, can enable the portable electronic device to perform the steps of the method disclosed in the embodiments. Figure 1 The steps of the method disclosed in the embodiments include:

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

[0140] Remove the dispersion energy in the dispersion spectrum except for the specified P-wave dispersion mode to obtain a target dispersion spectrum.

[0141] Inverse transform the target dispersion spectrum to the time-space domain to obtain a target seismic record corresponding to the specified P-wave dispersion mode.

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

[0143] Those skilled in the art will appreciate that embodiments of the present specification can be provided as methods, systems or computer program products. Accordingly, the present specification can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present specification can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer usable program code.

[0144] The above describes specific embodiments of the present specification. Other embodiments are within the scope of the appended claims. In some cases, the acts or steps recited in the claims can be performed in a different order than the order in which they are recited and still achieve the desired results. In addition, the processes depicted in the figures do not necessarily require the particular order shown, or sequential order, to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous or necessary.

[0145] The above merely provides embodiments of the present specification and is not intended to limit the present specification. The present specification can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present specification shall be included in the scope of claims of the present specification. In addition, all other embodiments obtained by those of ordinary skill in the art without creative labor shall be within the protection scope of the present 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 gather in the time-space domain, determining the dispersion energy spectrum corresponding to the marine seismic gather in the frequency-velocity domain, including: performing high-resolution linear Radon transform on the original seismic records corresponding to the marine seismic gather in the time-space domain to determine the high-resolution Radon transform coefficients corresponding to the marine seismic gather in the frequency-slowness domain; mapping the high-resolution Radon transform coefficients corresponding to the marine seismic 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 gather in the frequency-velocity domain; wherein the Radon coefficients belonging to the specified P waveguide dispersion mode remain unchanged, and the Radon coefficients not belonging to the specified P waveguide dispersion mode are set to 0; removing the dispersion energy other than the specified P-guided wave dispersion mode from 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 guided wave dispersion mode; Based on the original seismic record and the target seismic record, seismic data after removing the specified P-waveguide dispersion mode is determined.

2. 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 to determine 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; Represents the weighting matrix of Radon transform coefficients; represents the weighting matrix of seismic data; represents the forward transformation operator; represents the damping factor; A two-dimensional matrix representing single-frequency seismic data; A two-dimensional matrix representing the Radon coefficients; For each single-frequency seismic data, the high-resolution Radon transform coefficient calculation formula is calculated based on the conjugate gradient algorithm. and Iterate to determine the high-resolution Radon transform coefficient corresponding to each of the 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.

3. The method according to claim 2, characterized in that For each single-frequency seismic data, the high-resolution Radon transform coefficient calculation formula is calculated based on the conjugate gradient algorithm. and Iteration is performed to determine the high-resolution Radon transform coefficient corresponding to each of the 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 renew , and based on the formula renew ;in, Indicates the current iteration number; For the The high-resolution Radon transform coefficients obtained during the round of iterations; is the standard deviation of the residuals; ; Based on the formula and formula , calculate the variable and variables ;in, Indicates the The coefficient of round iteration; Indicates the The coefficient of round iteration; Solve linear equations using the conjugate gradient algorithm The root of The coefficient of round iteration Based on the formula , calculate the The high-resolution Radon transform coefficient vector of the round iteration .

4. The method according to claim 1, wherein Mapping the high-resolution Radon transform coefficients in the frequency-slowness domain to the frequency-velocity domain to perform dispersion energy spectrum imaging, and obtaining the dispersion energy 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 track gather in the frequency-velocity domain is obtained.

5. The method according to claim 1, wherein Removing the dispersion energy other than the specified P-guided wave dispersion mode in the dispersion energy spectrum to obtain a target dispersion energy spectrum, including: 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.

6. The method according to claim 5, characterized in that The designated P-waveguide dispersion mode is one or at least two.

7. The method according to claim 1, characterized in that Determining, based on the original seismic record and the target seismic record, 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.

8. 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 seabed medium corresponding to the marine seismic gather; and / or, Based on the seismic data after removing the specified P-guided wave dispersion mode, the influence of the P-guided wave on the seismic signal and its amplitude spectrum is analyzed to determine the denoised seismic data for migration imaging of the reflection wave.

9. A processing device for ocean P-guided wave removal and mode separation, characterized in that: include: A dispersion module is used to determine 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; wherein the Radon coefficients belonging to the specified P waveguide dispersion mode remain unchanged, and the Radon coefficients not belonging to the specified P waveguide dispersion mode are set to 0; a removal module, configured 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, configured to invert the target dispersion energy spectrum into the time-space domain to obtain a target seismic record corresponding to the specified P-guided wave dispersion mode; A processing module is used to determine the seismic data after removing the specified P-waveguide dispersion mode based on the original seismic record and the target seismic record.

10. 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 is caused to perform the method according to any one of claims 1 to 8.

11. A computer-readable storage medium, wherein the computer-readable storage medium is configured to store computer-executable instructions, wherein the computer-executable instructions implement the method according to any one of claims 1 to 8 when executed by a processor.

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