Time-frequency domain two-step method surface wave suppression method and device

Abstract

The invention relates to the field of seismic signal processing, and particularly discloses a time-frequency domain two-step surface wave suppression method and device, and the method comprises the steps: first-step surface wave suppression: inputting a seismic single shot, and carrying out the suppression of a low-frequency surface wave in a time-frequency domain based on the medium-high frequency information in a same seismic channel, so as to obtain a first-step surface wave suppression single shot and noise; and a second step of surface wave suppression: inputting the first step of surface wave suppression single shot, and based on the low-frequency information of the middle and far offset seismic trace, suppressing the near offset residual low-frequency surface wave in the time-frequency domain to obtain the single shot and noise after two-step suppression. According to the time-frequency domain two-step method surface wave suppression method provided by the invention, the characteristics of low frequency and strong energy of surface waves are utilized, medium-high frequency information is referred in the same seismic channel, and the low-frequency surface waves are suppressed by utilizing a time-frequency analysis method; by means of the characteristic that the offset distance of the surface waves in the same arrangement is small, the low-frequency information of middle and far offset distance channels is referred to, and the near-offset distance residual low-frequency surface waves are suppressed in the time-frequency domain.

Description

Technical Field

[0001] The invention relates to the field of seismic signal processing, and in particular to a two-step surface wave suppression method and device in time-frequency domain. Background Art

[0002] Surface wave suppression is a very important part of seismic data processing. Using a single technology to suppress surface waves often has poor results, which can be manifested in three situations: the first is that the surface waves are fully suppressed, but there are obvious effective signals in the noise; the second is that there are no obvious effective signals in the noise, but the surface waves are not completely suppressed; the third is that the surface waves are not completely suppressed, and there are obvious effective signals in the noise. It is difficult to effectively suppress surface waves without damaging effective signals. The characteristics of surface waves are low frequency, strong energy, and small offset distance within the same arrangement, which have a greater impact on imaging.

[0003] Based on this technical background, the present invention studies a two-step surface roll suppression method and device in time-frequency domain. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a two-step surface roll suppression method and device in time-frequency domain. The method utilizes the characteristics of low frequency and strong energy of surface rolls, refers to medium and high frequency information in the same seismic trace, and uses a time-frequency analysis method to suppress low-frequency surface rolls; utilizes the characteristic that surface rolls have a small offset in the same arrangement, refers to the low-frequency information of medium and far offset traces, and suppresses residual low-frequency surface rolls in the near-offset distance in the time-frequency domain; the method can suppress surface rolls well without damaging effective signals.

[0005] In order to achieve the above object, the first aspect of the present invention provides a two-step surface roll suppression method in time-frequency domain, comprising:

[0006] The first step of surface wave suppression: input a single seismic shot, and based on the medium and high frequency information in the same seismic trace, suppress the low-frequency surface wave in the time-frequency domain to obtain the first step of surface wave suppression single shot and noise;

[0007] The second step of surface roll suppression: the single shot of the first step of surface roll suppression is input, and based on the low-frequency information of the seismic traces at medium and long offsets, the residual low-frequency surface rolls at near offsets are suppressed in the time-frequency domain to obtain the single shot and noise after two steps of suppression.

[0008] A second aspect of the present invention provides a time-frequency domain two-step method surface roll suppression device, comprising:

[0009] The first step surface wave suppression module is used to input a seismic single shot, and based on the medium and high frequency information in the same seismic channel, suppress the low-frequency surface wave in the time-frequency domain to obtain the first step surface wave suppression single shot and noise;

[0010] The second-step surface roll suppression module is used to input the first-step surface roll suppression single shot, and based on the low-frequency information of the medium- and long-offset seismic traces, suppress the near-offset residual low-frequency surface roll in the time-frequency domain to obtain the single shot and noise after two-step suppression.

[0011] A third aspect of the present invention provides an electronic device, the electronic device comprising:

[0012] A memory storing executable instructions;

[0013] A processor, wherein the processor runs the executable instructions in the memory to implement the two-step surface roll suppression method in the time-frequency domain as described in the first aspect.

[0014] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the time-frequency domain two-step surface roll suppression method described in the first aspect.

[0015] The beneficial effects of the present invention include:

[0016] (1) The two-step surface roll suppression method in the time-frequency domain proposed in the present invention utilizes the characteristics of low frequency and strong energy of surface rolls, and refers to the medium and high frequency information in the same seismic trace to suppress low-frequency surface rolls using the time-frequency analysis method; and utilizes the characteristic of small offset distance of surface rolls in the same arrangement, and refers to the low-frequency information of medium and long offset traces to suppress the residual low-frequency surface rolls in the near-offset distance in the time-frequency domain.

[0017] (2) The two-step surface roll suppression method in the time-frequency domain proposed in the present invention can effectively suppress surface roll interference, improve the data signal-to-noise ratio, do not damage the effective signal, and have good fidelity.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

[0020] Figure 1 This is a flow chart of the two-step surface roll suppression method in the time-frequency domain proposed by the present invention.

[0021] Figure 2 A schematic diagram of the flow of the surface wave suppression method in the prior art

[0022] Figure 3 This is a schematic diagram of the surface roll suppression process in a specific implementation of the time-frequency domain two-step surface roll suppression method proposed by the present invention.

[0023] Figure 4This is a schematic diagram of the first step of surface roll suppression process in a specific implementation of the two-step time-frequency domain surface roll suppression method proposed by the present invention.

[0024] Figure 5 This is a schematic diagram of the second step of surface roll suppression process in a specific implementation of the two-step time-frequency domain surface roll suppression method proposed by the present invention.

[0025] Figure 6 It is an original single shot in a specific implementation of the two-step surface roll suppression method in the time-frequency domain proposed by the present invention.

[0026] Figure 7 In a specific implementation of the time-frequency domain two-step surface roll suppression method proposed by the present invention, a single shot after surface roll suppression is performed using a conventional method.

[0027] Figure 8 This is a surface roll removed by conventional methods in a specific implementation of the two-step surface roll suppression method in the time-frequency domain proposed by the present invention.

[0028] Fig. 9 This is a single shot after the first step of surface roll suppression in a specific implementation of the two-step time-frequency domain surface roll suppression method proposed by the present invention.

[0029] Fig.10 This is the surface roll after the first step of surface roll suppression in a specific implementation of the two-step surface roll suppression method in the time-frequency domain proposed by the present invention.

[0030] Fig.11 This is a single shot after the second step of surface roll suppression in a specific implementation of the two-step time-frequency domain surface roll suppression method proposed by the present invention.

[0031] Fig.12 This is the surface roll after the second step of surface roll suppression in a specific implementation of the two-step surface roll suppression method in the time-frequency domain proposed by the present invention.

[0032] Fig.13 This is a two-step surface roll removal method in a specific implementation manner of the two-step surface roll suppression method in the time-frequency domain proposed by the present invention.

[0033] Fig.14 This is a stacked section before surface roll suppression in a specific implementation of the two-step time-frequency domain surface roll suppression method proposed by the present invention.

[0034] Fig.15 This is a specific implementation of the two-step time-frequency domain surface roll suppression method proposed by the present invention, in which the surface rolls are removed and then the sections are superimposed.

[0035] Fig.16 This is the noise profile removed in a specific implementation of the two-step surface roll suppression method in the time-frequency domain proposed by the present invention. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0037] The present invention provides a two-step surface roll suppression method in time-frequency domain, such as Figure 1 ,include:

[0038] The first step of surface wave suppression: input a single seismic shot, and based on the medium and high frequency information in the same seismic trace, suppress the low-frequency surface wave in the time-frequency domain to obtain the first step of surface wave suppression single shot and noise;

[0039] The second step of surface roll suppression: the single shot of surface roll suppression in the first step is input, and based on the low-frequency information of the seismic traces at medium and long offsets, the residual low-frequency surface rolls at near offsets are suppressed in the time-frequency domain to obtain the single shot and noise after two steps of suppression.

[0040] In the present invention, the characteristics of surface rolls being low frequency and strong energy are utilized, and medium and high frequency information is referred to within the same seismic trace, and the low-frequency surface rolls are suppressed by the time-frequency analysis method; the characteristic of surface rolls being small in the same arrangement is utilized, and the low-frequency information of medium and far offset traces is referred to, and the residual low-frequency surface rolls at near offsets are suppressed in the time-frequency domain.

[0041] According to the present invention, the first step of surface wave suppression and the second step of surface wave suppression both include:

[0042] The time-frequency analysis stage, the noise suppression coefficient determination stage and the time-frequency denoising stage.

[0043] According to the present invention, the first step of surface roll suppression, the time-frequency analysis stage, comprises:

[0044] Perform spectrum analysis, filtering and frequency scanning on the input seismic single shot to determine the maximum frequency of the surface wave and the maximum frequency of the effective wave;

[0045] Based on the maximum frequency of the surface wave and the maximum frequency of the effective wave, determining the suppression frequency band of the surface wave and the reference frequency band of the effective wave;

[0046] The first step of surface wave suppression is to determine the noise coefficient, which includes:

[0047] The input seismic single shot is cut off to obtain the single shot after the surface wave is cut off;

[0048] The single shot after the surface wave is removed is filtered in the suppression frequency band of the surface wave and the reference frequency band of the effective wave to obtain the suppression single shot and the effective single shot;

[0049] Calculate the average absolute amplitude of the suppressed single shot and the effective single shot respectively;

[0050] The ratio of the average absolute amplitude of the suppressed single shot to the average absolute amplitude of the effective single shot is calculated and this ratio is used as the suppression noise coefficient.

[0051] According to the present invention, the first step of surface roll suppression, the time-frequency denoising stage, comprises:

[0052] Perform time-frequency domain wavelet decomposition on each seismic trace in the input seismic single shot to obtain seismic wavelet sets in different frequency bands;

[0053] Obtain the average energy of all sub-waves in the reference frequency band of the effective wave of the seismic wavelet concentration;

[0054] Obtain the energy of a single sub-wave in the suppressed frequency band of the seismic wavelet concentration surface wave;

[0055] Calculate the ratio of the energy of the single wavelet to the average energy of all wavelets in the reference frequency band, and use the ratio as the noise factor;

[0056] Compare the noise coefficient and the noise suppression coefficient. If the noise coefficient is less than or equal to the noise suppression coefficient, the wavelet is not a surface wave. If the noise coefficient is greater than the noise suppression coefficient, the wavelet is a surface wave and is removed from the input seismic shot. Repeat the above operation until all wavelets that are surface waves are removed from the input seismic shot to obtain the first step surface wave suppression shot.

[0057] According to the present invention, the time-frequency analysis stage of the second step of surface roll suppression includes:

[0058] Perform spectrum analysis, filtering and frequency scanning on the first step surface wave suppression single shot to determine the maximum frequency of the residual surface wave and the dominant frequency of the effective wave;

[0059] Based on the maximum frequency of the residual surface wave and the dominant frequency of the effective wave, the suppression frequency band of the residual surface wave and the reference frequency band of the effective wave are determined;

[0060] The second step of surface wave suppression is to determine the noise coefficient stage, which includes:

[0061] The single shot of surface wave suppression in the first step is cut off to obtain single shot in the area with surface wave and single shot in the area without surface wave;

[0062] The single shot in the area with surface waves and the single shot in the area without surface waves are filtered in the reference frequency band of the effective wave to obtain the cannon with surface waves and the cannon without surface waves;

[0063] Calculate the average absolute amplitude of the cannon with and without surface wave, respectively;

[0064] The ratio of the average absolute amplitude of the surface wave cannon to the average absolute amplitude of the surface wave cannon is calculated, and this ratio is used as the noise suppression coefficient.

[0065] According to the present invention, the time-frequency denoising stage of the second step surface roll suppression includes:

[0066] The single shot in the area without surface waves is filtered in the suppression frequency band of the residual surface waves to obtain the residual suppression shot;

[0067] Find the average absolute amplitude of the residual suppression guns;

[0068] Perform time-frequency domain wavelet decomposition on each seismic trace for a single shot in the surface wave area to obtain seismic wavelet sets in different frequency bands;

[0069] Obtain the energy of a single sub-wave in the seismic wavelet set within the suppressed frequency band;

[0070] Calculate the ratio of the energy of the single sub-wave to the average absolute amplitude of the residual suppression gun, and use the ratio as the noise factor;

[0071] Compare the noise coefficient and the compression noise coefficient. If the noise coefficient is less than or equal to the compression noise coefficient, the wavelet is not a surface wave. If the noise coefficient is greater than the compression noise coefficient, the wavelet is a surface wave and is removed from the first step of surface wave suppression single shot. Repeat the above operation until all wavelets that are surface waves are removed from the first step of surface wave suppression single shot to obtain a single shot after two steps of suppression.

[0072] Preferably, all wavelets that are not surface waves are effective wave single shots after two-step suppression, and all wavelets that are surface waves are noises after two-step suppression.

[0073] The method of the present invention can well suppress surface wave interference, improve the data signal-to-noise ratio, do not damage the effective signal, and has good fidelity.

[0074] The present invention will be described in more detail below by way of examples.

[0075] Embodiment 1:

[0076] The conventional surface wave suppression process is as follows: Figure 2 As shown, the implementation steps are as follows:

[0077] 1) Input a single seismic shot;

[0078] 2) Perform surface wave suppression;

[0079] 3) Get the single shot and noise after surface wave suppression.

[0080] like Figure 3 As shown, this embodiment provides an overall process of a two-step surface roll suppression method in the time-frequency domain, and the implementation steps are as follows:

[0081] 1) Input a single seismic shot;

[0082] 2) Within the same seismic trace, refer to the medium and high frequency information and use the time-frequency method to suppress the low-frequency surface waves;

[0083] 3) Refer to the low-frequency information of the medium- and long-offset seismic traces to suppress the residual low-frequency surface waves at near offset in the time-frequency domain;

[0084] 4) Obtain single shot and noise after surface wave suppression;

[0085] Among them, the first step of surface wave suppression process is as follows Figure 4 As shown, the implementation steps are as follows:

[0086] 1) Input seismic single shot A;

[0087] 2) Perform spectrum analysis, filtering and frequency scanning on single seismic shots;

[0088] 3) Determine the maximum frequency f1 of the surface wave;

[0089] 4) Determine the maximum effective wave frequency f2;

[0090] 5) Determine the suppression frequency range of the surface wave as 0-f1 and the reference frequency range of the effective wave as f1-f2;

[0091] 6) Cut off the input seismic single shot A, cut off the surface wave, and obtain the single shot B after cutting off the surface wave;

[0092] 7) Perform 0-f1 filtering on single shot B to obtain single shot C;

[0093] 8) Calculate the average absolute amplitude e1 for single shot C;

[0094] 9) Filter single shot B by f1-f2 to obtain single shot D;

[0095] 10) Calculate the average absolute amplitude e2 for a single shot D;

[0096] 11) Divide e2 by e1 to obtain the noise reduction coefficient R1;

[0097] 12) Perform time-frequency domain wavelet decomposition on each seismic trace in the seismic single shot A to obtain seismic wavelet sets in different frequency bands;

[0098] 13) Calculate the average energy e4 of all sub-waves in the reference frequency range f1-f2 in the wavelet set;

[0099] 14) Obtain the energy e3 of a single sub-wave in the sub-wave concentrated suppression frequency range 0-f1;

[0100] 15) For a single sub-wave in the suppressed frequency range 0-f1, calculate the noise coefficient R2, R2 = e3 / e4;

[0101] 16) Compare the noise coefficient R2 and the noise suppression coefficient R1 of a single sub-wave in the suppressed frequency range 0-f1. If the R2 of a sub-wave is less than or equal to R1, the sub-wave is considered not to be a surface wave; if the R2 of a sub-wave is greater than R1, the sub-wave is considered to be a surface wave, denoted by W;

[0102] 17) Subtract the surface wave W from the seismic single shot A to obtain the single shot E after removing the surface wave;

[0103] 18) Assign the single shot E to the single shot A, and repeat 14)-17) until all sub-waves in the 0-f1 frequency range are processed, and the single shot E after removing the surface wave is obtained, and the process ends;

[0104] Among them, the second step of surface wave suppression process is as follows Figure 5 As shown, the implementation steps are as follows:

[0105] 1) Input seismic single shot A;

[0106] 2) Perform spectrum analysis, filtering and frequency scanning on single seismic shots;

[0107] 3) Determine the maximum frequency f1 of the residual surface wave;

[0108] 4) Determine the effective wave dominant frequency f2;

[0109] 5) Determine the suppression frequency range of the residual surface wave as 0-f1 and the reference frequency range of the effective wave as f1-f2;

[0110] 6) Cut off the input seismic single shot A and remove the surface wave to obtain the single shot B with only the surface wave area and the single shot C with no surface wave area;

[0111] 7) Perform f1-f2 filtering on the single shot B with only the surface wave area to obtain the single shot D;

[0112] 8) Calculate the average absolute amplitude e1 for a single shot D;

[0113] 9) Filter the single shot C in the area without surface waves by f1-f2 to obtain the single shot E;

[0114] 10) Calculate the average absolute amplitude e2 for a single shot E;

[0115] 11) Divide e2 by e1 to obtain the noise reduction coefficient R1;

[0116] 12) Perform 0-f1 filtering on the single shot C in the area without surface waves to obtain the single shot F;

[0117] 13) Calculate the average absolute amplitude e4 for a single shot F;

[0118] 14) Only in the surface wave area, each seismic trace in the single shot B is decomposed in the time-frequency domain to obtain seismic wavelet sets in different frequency bands;

[0119] 15) Obtain the energy e3 of a single sub-wave in the sub-wave concentrated suppression frequency range 0-f1;

[0120] 16) For a single sub-wave in the suppressed frequency range 0-f1, calculate the noise coefficient R2, R2 = e3 / e4;

[0121] 17) Compare the noise coefficient R2 and the compression noise coefficient R1 of a single sub-wave in the suppressed frequency range 0-f1. If the R2 of a sub-wave is less than or equal to R1, it is considered that the sub-wave is not a surface wave; if the R2 of a sub-wave is greater than R1, it is considered that the sub-wave is a surface wave, denoted by W;

[0122] 18) Subtract the surface wave W from the seismic single shot A to obtain the single shot G after removing the surface wave;

[0123] 19) Assign the single shot G to the single shot A, and repeat 15)-18) until all sub-waves in the 0-f1 frequency band are processed, and the single shot G is obtained after removing the surface wave, and the process ends.

[0124] In this embodiment, Figure 6 For the original single gun, Figure 7 This is a single shot after surface wave suppression using conventional methods. There are a lot of surface waves remaining at the arrow-marked part of the single shot. Figure 8 For the surface wave single shot removed by conventional methods, there is effective wave damage in the area marked by the box; the conventional method shows that on the one hand, the surface wave is not completely suppressed, and on the other hand, the effective signal is damaged;

[0125] Fig. 9 This is a single shot after the first step of surface wave suppression in the present invention. As can be seen from the figure, most of the surface waves are suppressed in the first step, but some surface waves still remain; Fig.11 This is a single shot after the second step of surface wave suppression in the present invention. It can be seen from the figure that the residual surface wave in the first step is effectively suppressed; Fig.10 , Fig.12 and Fig.13 They are the surface waves removed in the first step, the surface waves removed in the second step, and the surface waves removed in the two-step method. It can be seen from the figure that no effective signal is seen in the noise single shot; the method of the present invention shows that the surface waves are effectively suppressed on the one hand, and the effective signal is not damaged on the other hand;

[0126] Fig.14 is the stacked section before surface wave suppression, Fig.15 This is the superimposed section after the surface roll is removed in the present invention. Comparing the two figures, it can be seen that the surface roll is effectively suppressed and the signal-to-noise ratio of the section is significantly improved. Fig.16 This is the noise profile removed by the present invention. No effective signal is found in the noise profile, indicating that the present invention has good fidelity.

[0127] Embodiment 2:

[0128] This embodiment provides a two-step surface roll suppression method in the time-frequency domain, such as Figure 1 As shown, including:

[0129] The first step of surface wave suppression: input a single seismic shot, and based on the medium and high frequency information in the same seismic trace, suppress the low-frequency surface wave in the time-frequency domain to obtain the first step of surface wave suppression single shot and noise;

[0130] The second step of surface wave suppression: input the single shot of surface wave suppression in the first step, and suppress the residual low-frequency surface waves at near offset in the time-frequency domain based on the low-frequency information of seismic traces at medium and long offsets to obtain the single shot and noise after two steps of suppression;

[0131] The first step of surface wave suppression and the second step of surface wave suppression both include:

[0132] The time-frequency analysis stage, the noise suppression coefficient determination stage and the time-frequency denoising stage.

[0133] According to the present invention, the first step of surface roll suppression, the time-frequency analysis stage, comprises:

[0134] Perform spectrum analysis, filtering and frequency scanning on the input seismic single shot to determine the maximum frequency of the surface wave and the maximum frequency of the effective wave;

[0135] Based on the maximum frequency of the surface wave and the maximum frequency of the effective wave, determining the suppression frequency band of the surface wave and the reference frequency band of the effective wave;

[0136] The first step of surface wave suppression is to determine the noise coefficient, which includes:

[0137] The input seismic single shot is cut off to obtain the single shot after the surface wave is cut off;

[0138] The single shot after the surface wave is removed is filtered in the suppression frequency band of the surface wave and the reference frequency band of the effective wave to obtain the suppression single shot and the effective single shot;

[0139] Calculate the average absolute amplitude of the suppressed single shot and the effective single shot respectively;

[0140] Calculate the ratio of the average absolute amplitude of the suppressed single shot to the average absolute amplitude of the effective single shot, and use the ratio as the suppression noise coefficient;

[0141] The first step of surface roll suppression, the time-frequency denoising stage, includes:

[0142] Perform time-frequency domain wavelet decomposition on each seismic trace in the input seismic single shot to obtain seismic wavelet sets in different frequency bands;

[0143] Obtain the average energy of all sub-waves in the reference frequency band of the effective wave of the seismic wavelet concentration;

[0144] Obtain the energy of a single sub-wave in the suppressed frequency band of the seismic wavelet concentration surface wave;

[0145] Calculate the ratio of the energy of the single wavelet to the average energy of all wavelets in the reference frequency band, and use the ratio as the noise factor;

[0146] Compare the noise coefficient and the noise suppression coefficient. If the noise coefficient is less than or equal to the noise suppression coefficient, the wavelet is not a surface wave. If the noise coefficient is greater than the noise suppression coefficient, the wavelet is a surface wave and is removed from the input seismic single shot. Repeat the above operation until all the wavelets that are surface waves are removed from the input seismic single shot to obtain the first step of surface wave suppression single shot.

[0147] The second step of surface roll suppression, the time-frequency analysis phase, includes:

[0148] Perform spectrum analysis, filtering and frequency scanning on the first step surface wave suppression single shot to determine the maximum frequency of the residual surface wave and the dominant frequency of the effective wave;

[0149] Based on the maximum frequency of the residual surface wave and the dominant frequency of the effective wave, the suppression frequency band of the residual surface wave and the reference frequency band of the effective wave are determined;

[0150] The second step of surface wave suppression is to determine the noise coefficient stage, which includes:

[0151] The single shot of surface wave suppression in the first step is cut off to obtain single shot in the area with surface wave and single shot in the area without surface wave;

[0152] The single shot in the area with surface waves and the single shot in the area without surface waves are filtered in the reference frequency band of the effective wave to obtain the cannon with surface waves and the cannon without surface waves;

[0153] Calculate the average absolute amplitude of the cannon with and without surface wave, respectively;

[0154] Calculate the ratio of the average absolute amplitude of the surface wave gun to the average absolute amplitude of the surface wave gun without the surface wave gun, and use the ratio as the noise suppression coefficient;

[0155] The second step of surface roll suppression, the time-frequency denoising stage, includes:

[0156] The single shot in the area without surface waves is filtered in the suppression frequency band of the residual surface waves to obtain the residual suppression shot;

[0157] Find the average absolute amplitude of the residual suppression guns;

[0158] Perform time-frequency domain wavelet decomposition on each seismic trace for a single shot in the surface wave area to obtain seismic wavelet sets in different frequency bands;

[0159] Obtain the energy of a single sub-wave in the seismic wavelet set within the suppressed frequency band;

[0160] Calculate the ratio of the energy of the single sub-wave to the average absolute amplitude of the residual suppression gun, and use the ratio as the noise factor;

[0161] Compare the noise coefficient and the noise suppression coefficient. If the noise coefficient is less than or equal to the noise suppression coefficient, the wavelet is not a surface wave. If the noise coefficient is greater than the noise suppression coefficient, the wavelet is a surface wave and is removed from the first step of surface wave suppression single shot. Repeat the above operation until all the wavelets that are surface waves are removed from the first step of surface wave suppression single shot to obtain a single shot after two steps of suppression.

[0162] All sub-waves that are not surface waves are effective wave single shots after two-step suppression, and all sub-waves that are surface waves are noises after two-step suppression.

[0163] Embodiment three:

[0164] This embodiment provides a time-frequency domain two-step surface roll suppression device, comprising:

[0165] The first step surface wave suppression module is used to input a seismic single shot, and based on the medium and high frequency information in the same seismic channel, suppress the low-frequency surface wave in the time-frequency domain to obtain the first step surface wave suppression single shot and noise;

[0166] The second-step surface wave suppression module is used to input the first-step surface wave suppression single shot, and based on the low-frequency information of the medium- and long-offset seismic traces, suppress the near-offset residual low-frequency surface waves in the time-frequency domain to obtain the single shot and noise after two-step suppression;

[0167] The first step of surface wave suppression and the second step of surface wave suppression both include:

[0168] The time-frequency analysis stage, the noise suppression coefficient determination stage and the time-frequency denoising stage.

[0169] According to the present invention, the first step of surface roll suppression, the time-frequency analysis stage, comprises:

[0170] Perform spectrum analysis, filtering and frequency scanning on the input seismic single shot to determine the maximum frequency of the surface wave and the maximum frequency of the effective wave;

[0171] Based on the maximum frequency of the surface wave and the maximum frequency of the effective wave, determining the suppression frequency band of the surface wave and the reference frequency band of the effective wave;

[0172] The first step of surface wave suppression is to determine the noise coefficient, which includes:

[0173] The input seismic single shot is cut off to obtain the single shot after the surface wave is cut off;

[0174] The single shot after the surface wave is removed is filtered in the suppression frequency band of the surface wave and the reference frequency band of the effective wave to obtain the suppression single shot and the effective single shot;

[0175] Calculate the average absolute amplitude of the suppressed single shot and the effective single shot respectively;

[0176] Calculate the ratio of the average absolute amplitude of the suppressed single shot to the average absolute amplitude of the effective single shot, and use the ratio as the suppression noise coefficient;

[0177] The first step of surface roll suppression, the time-frequency denoising stage, includes:

[0178] Perform time-frequency domain wavelet decomposition on each seismic trace in the input seismic single shot to obtain seismic wavelet sets in different frequency bands;

[0179] Obtain the average energy of all sub-waves in the reference frequency band of the effective wave of the seismic wavelet concentration;

[0180] Obtain the energy of a single sub-wave in the suppressed frequency band of the seismic wavelet concentration surface wave;

[0181] Calculate the ratio of the energy of the single wavelet to the average energy of all wavelets in the reference frequency band, and use the ratio as the noise factor;

[0182] Compare the noise coefficient and the noise suppression coefficient. If the noise coefficient is less than or equal to the noise suppression coefficient, the wavelet is not a surface wave. If the noise coefficient is greater than the noise suppression coefficient, the wavelet is a surface wave and is removed from the input seismic single shot. Repeat the above operation until all the wavelets that are surface waves are removed from the input seismic single shot to obtain the first step of surface wave suppression single shot.

[0183] The second step of surface roll suppression, the time-frequency analysis phase, includes:

[0184] Perform spectrum analysis, filtering and frequency scanning on the first step surface wave suppression single shot to determine the maximum frequency of the residual surface wave and the dominant frequency of the effective wave;

[0185] Based on the maximum frequency of the residual surface wave and the dominant frequency of the effective wave, the suppression frequency band of the residual surface wave and the reference frequency band of the effective wave are determined;

[0186] The second step of surface wave suppression is to determine the noise coefficient stage, which includes:

[0187] The single shot of surface wave suppression in the first step is cut off to obtain single shot in the area with surface wave and single shot in the area without surface wave;

[0188] The single shot in the area with surface waves and the single shot in the area without surface waves are filtered in the reference frequency band of the effective wave to obtain the cannon with surface waves and the cannon without surface waves;

[0189] Calculate the average absolute amplitude of the cannon with and without surface wave, respectively;

[0190] Calculate the ratio of the average absolute amplitude of the surface wave gun to the average absolute amplitude of the surface wave gun without the surface wave gun, and use the ratio as the noise suppression coefficient;

[0191] The second step of surface roll suppression, the time-frequency denoising stage, includes:

[0192] The single shot in the area without surface waves is filtered in the suppression frequency band of the residual surface waves to obtain the residual suppression shot;

[0193] Find the average absolute amplitude of the residual suppression guns;

[0194] Perform time-frequency domain wavelet decomposition on each seismic trace for a single shot in the surface wave area to obtain seismic wavelet sets in different frequency bands;

[0195] Obtain the energy of a single sub-wave in the seismic wavelet set within the suppressed frequency band;

[0196] Calculate the ratio of the energy of the single sub-wave to the average absolute amplitude of the residual suppression gun, and use the ratio as the noise factor;

[0197] Compare the noise coefficient and the noise suppression coefficient. If the noise coefficient is less than or equal to the noise suppression coefficient, the wavelet is not a surface wave. If the noise coefficient is greater than the noise suppression coefficient, the wavelet is a surface wave and is removed from the first step of surface wave suppression single shot. Repeat the above operation until all the wavelets that are surface waves are removed from the first step of surface wave suppression single shot to obtain a single shot after two steps of suppression.

[0198] All wavelets that are not surface waves are valid wavelets after two-step suppression, and all wavelets that are surface waves are noises after two-step suppression.

[0199] Embodiment 4:

[0200] An embodiment of the present invention provides an electronic device including a memory and a processor.

[0201] A memory storing executable instructions;

[0202] The processor runs the executable instructions in the memory to implement the two-step surface roll suppression method in the time-frequency domain.

[0203] The memory is used to store non-temporary computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0204] The processor may be a central processing unit (CPU) or other forms of processing units with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of the present invention, the processor is used to run the computer-readable instructions stored in the memory.

[0205] Those skilled in the art should be able to understand that in order to solve the technical problem of how to obtain a good user experience, the present embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the protection scope of the present invention.

[0206] For detailed description of this embodiment, reference may be made to the corresponding descriptions in the aforementioned embodiments, which will not be repeated here.

[0207] Embodiment five:

[0208] An embodiment of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, a two-step surface roll suppression method in the time-frequency domain is implemented.

[0209] The computer-readable storage medium according to the embodiment of the present invention stores non-transitory computer-readable instructions, and when the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the above-mentioned methods of the embodiments of the present invention are executed.

[0210] The above-mentioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or mobile hard disk), media with built-in rewritable non-volatile memory (e.g., memory card) and media with built-in ROM (e.g., ROM box).

[0211] The two-step time-frequency domain surface roll suppression method proposed in the embodiment of the present invention utilizes the characteristics of low frequency and strong energy of surface rolls, refers to medium and high frequency information in the same seismic trace, and uses a time-frequency analysis method to suppress low-frequency surface rolls; utilizes the characteristic of small offset distance of surface rolls in the same arrangement, refers to the low-frequency information of medium and far offset traces, and suppresses residual low-frequency surface rolls in the near-offset distance in the time-frequency domain.

[0212] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A two-step surface wave suppression method in the time-frequency domain, characterized in that, it includes: The first step of surface wave suppression: Input a single seismic shot, and based on the medium and high frequency information within the same seismic trace, suppress the low-frequency surface wave in the time-frequency domain to obtain the single seismic shot and noise after the first step of surface wave suppression; The second step of surface wave suppression: Input the single seismic shot after the first step of surface wave suppression, and based on the low-frequency information of the medium and far offset seismic traces, suppress the low-frequency surface wave remaining in the near offset in the time-frequency domain to obtain the single seismic shot and noise after two-step suppression.

2. The method according to claim 1, characterized in that, both the first step of surface wave suppression and the second step of surface wave suppression steps include: a time-frequency analysis stage, a stage of determining the noise suppression coefficient, and a time-frequency denoising stage.

3. The method according to claim 2, characterized in that, the time-frequency analysis stage of the first step of surface wave suppression includes: performing spectral analysis, filtering and frequency scanning on the input single seismic shot to determine the maximum surface wave frequency and the maximum effective wave frequency; based on the maximum surface wave frequency and the maximum effective wave frequency, determining the suppression frequency band of the surface wave and the reference frequency band of the effective wave; the stage of determining the noise suppression coefficient of the first step of surface wave suppression includes: performing excision on the input single seismic shot to obtain a single seismic shot after excision of the surface wave; filtering the single seismic shot after excision of the surface wave in the suppression frequency band of the surface wave and the reference frequency band of the effective wave respectively to obtain a suppressed single seismic shot and an effective single seismic shot; respectively obtaining the average absolute amplitude of the suppressed single seismic shot and the effective single seismic shot; calculating the ratio of the average absolute amplitude of the suppressed single seismic shot to the average absolute amplitude of the effective single seismic shot, and taking this ratio as the noise suppression coefficient.

4. The method according to claim 3, characterized in that, the time-frequency denoising stage of the first step of surface wave suppression includes: performing time-frequency domain wavelet decomposition on each seismic trace in the input single seismic shot to obtain a set of seismic wavelets in different frequency bands; obtaining the average value of the energies of all wavelets within the reference frequency band of the effective wave in the set of seismic wavelets; obtaining the energy of a single wavelet within the suppression frequency band of the surface wave in the set of seismic wavelets; calculating the ratio of the energy of this single wavelet to the average value of the energies of all wavelets within the reference frequency band, and taking this ratio as the noise coefficient; comparing the magnitudes of the noise coefficient and the noise suppression coefficient. If the noise coefficient is less than or equal to the noise suppression coefficient, then this wavelet is not a surface wave. If the noise coefficient is greater than the noise suppression coefficient, then this wavelet is a surface wave, and it is removed from the input single seismic shot. Repeat the above operations until all wavelets that are surface waves are removed from the input single seismic shot to obtain the single seismic shot after the first step of surface wave suppression.

5. The method according to claim 2, characterized in that, the time-frequency analysis stage of the second step of surface wave suppression includes: performing spectral analysis, filtering and frequency scanning on the single seismic shot after the first step of surface wave suppression to determine the maximum frequency of the remaining surface wave and the dominant frequency of the effective wave; based on the maximum frequency of the remaining surface wave and the dominant frequency of the effective wave, determining the suppression frequency band of the remaining surface wave and the reference frequency band of the effective wave; the stage of determining the noise suppression coefficient of the second step of surface wave suppression includes: performing excision on the single seismic shot after the first step of surface wave suppression to obtain a single seismic shot with a surface wave area and a single seismic shot without a surface wave area; Filter the single shot in the surface wave region and the single shot in the non-surface wave region respectively in the reference frequency band of the effective wave to obtain the surface wave shot and the non-surface wave shot; Respectively obtain the average absolute amplitude of the surface wave shot and the non-surface wave shot; Calculate the ratio of the average absolute amplitude of the surface wave shot to the average absolute amplitude of the non-surface wave shot, and use this ratio as the noise suppression coefficient.

6. The method according to claim 5, wherein, The time-frequency denoising stage of the second-step surface wave suppression includes: Filter the single shot in the non-surface wave region in the suppression frequency band of the residual surface wave to obtain the residual suppression shot; Obtain the average absolute amplitude of the residual suppression shot; Perform time-frequency domain wavelet decomposition on the single shot in the surface wave region for each seismic trace to obtain a set of seismic wavelets in different frequency bands; Obtain the energy of a single wavelet within the suppression frequency band of the set of seismic wavelets; Calculate the ratio of the energy of this single wavelet to the average absolute amplitude of the residual suppression shot, and use this ratio as the noise coefficient; Compare the magnitudes of the noise coefficient and the noise suppression coefficient. If the noise coefficient is less than or equal to the noise suppression coefficient, then this wavelet is not a surface wave. If the noise coefficient is greater than the noise suppression coefficient, then this wavelet is a surface wave, and remove it from the single shot of the first-step surface wave suppression. Repeat the above operations until all the wavelets that are surface waves are removed from the single shot of the first-step surface wave suppression, and then obtain the single shot after two-step suppression.

7. The method according to claim 6, wherein, All wavelets that are not surface waves are the effective wave single shot after two-step suppression, and all wavelets that are surface waves are the noise after two-step suppression.

8. A time-frequency domain two-step surface wave suppression device, wherein, Comprises: A first-step surface wave suppression module, configured to input a seismic single shot, and based on the medium and high frequency information within the same seismic trace, suppress the low-frequency surface wave in the time-frequency domain to obtain the first-step surface wave suppression single shot and noise; A second-step surface wave suppression module, configured to input the first-step surface wave suppression single shot, and based on the low-frequency information of the mid-to-far offset seismic traces, suppress the near-offset residual low-frequency surface wave in the time-frequency domain to obtain the single shot and noise after two-step suppression.

9. An electronic device, wherein, The electronic device includes: A memory, storing executable instructions; A processor, the processor runs the executable instructions in the memory to implement the time-frequency domain two-step surface wave suppression method according to any one of claims 1-7.

10. A computer-readable storage medium, wherein, This computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the time-frequency domain two-step surface wave suppression method according to any one of claims 1-7.

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