A land interlayer multiple wave suppression method and device

Abstract

The application provides a land interlayer multiple wave suppression method and device, and relates to the technical field of seismic data processing. The technical scheme is as follows: a land interlayer multiple wave suppression method comprises the following steps: acquiring seismic data which needs to be subjected to land interlayer multiple wave suppression; performing far-offset noise cutting and random noise suppression on the seismic data to obtain denoised data; based on the denoised data, fitting an amplitude curve by using middle and far offset distance data in multiple wave removal, and approximately calculating theoretical seismic data which does not contain multiple waves according to the amplitude curve; calculating a normalized cross-correlation coefficient of the theoretical seismic data and actual data; and performing data reconstruction according to the normalized cross-correlation coefficient to obtain seismic data after land interlayer multiple wave suppression. The application has the beneficial effect of suppressing land seismic near-trace interlayer multiple waves by using AVA fitting and data reconstruction based on a normalized cross-correlation coefficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seismic data processing, in particular to a land interlayer multiple wave suppression method and device. BACKGROUND

[0002] Multiple wave attenuation is one of the most prominent problems in land seismic data processing. At present, there are two main methods for land multiple wave attenuation: filtering method and attenuation method based on wave theory. The filtering method mainly uses the apparent velocity difference between multiple wave and primary wave or the periodicity of multiple wave (such as predictive deconvolution method) and other characteristics. This method is fast in calculation. However, it can only effectively attenuate land multiple wave when the apparent velocity difference between primary wave and multiple wave is large.

[0003] Therefore, for the middle and far offset part of land seismic data, the difference between primary wave and multiple wave is large, and the conventional filtering method can be used to suppress it. However, in the near offset part, the difference between multiple wave and primary wave is small, and they interfere with each other, making it difficult to suppress. The existence of residual interlayer multiple wave, especially near trace interlayer multiple wave, will affect the accuracy of prestack inversion. In order to protect the effective signal, the current suppression method still has a lot of near trace multiple wave, which seriously affects the use of near trace information by AVO technology. SUMMARY

[0004] In view of the above problems, the present application is proposed to provide a land interlayer multiple wave suppression method and device to overcome the above problems or at least partially solve the above problems.

[0005] In order to achieve the above purpose, the present application provides a land interlayer multiple wave suppression method, characterized in that it comprises:

[0006] Obtaining seismic data that needs to be suppressed by land interlayer multiple wave;

[0007] Performing far trace noise cutting and random noise suppression on the seismic data to obtain denoised data;

[0008] Based on the denoised data, fitting an amplitude curve in the middle and far offset part by using multiple wave removal, and approximately calculating a theoretical seismic data that does not contain multiple wave according to the amplitude curve;

[0009] Calculating the normalized cross-correlation coefficient of the theoretical seismic data and the original seismic data;

[0010] According to the normalized cross-correlation coefficient, reconstructing the data to obtain land interlayer multiple wave suppressed seismic data.

[0011] The seismic data that needs to be suppressed by land interlayer multiple wave is time domain or depth domain common imaging point seismic data.

[0012] The far trace noise removal is to adopt double travel time, offset data to form a removal line, and to remove the common imaging point seismic data.

[0013] On the basis of the common imaging point seismic data removal, the random noise suppression is performed. The random noise suppression method removes the noise without losing the high frequency information and reducing the lateral resolution, further suppresses the random noise, and improves the signal to noise ratio.

[0014] The relationship between the sampling value of the seismic signal at any t time and the offset in the common imaging point seismic data is represented by a polynomial;

[0015] The polynomial is: ; (1)

[0016] In the formula, xi is the offset of the i th trace; is the amplitude value of the i th trace at t time; is a constant coefficient; is a high-order error. The polynomial neglects the high-order error and can be represented by a vector matrix formula, which is specifically:

[0017]

[0018] (2) The damping least square method is adopted to solve the coefficients of the polynomial.

[0019] Specifically, the objective function is constructed, and the vector matrix formula can also be written as

[0020]

[0021] ; (3) At the minimum value of the objective function, that is, when

[0022] , the least square estimation formula of the coefficients of the polynomial is obtained:

[0023] ; (4)

[0024] In the formula, x is the offset of the i th trace; ;

[0025] The advantage of adopting the damping least square method to solve the polynomial coefficients is that is a symmetric positive definite matrix, and therefore can be orthogonally decomposed into , wherein R is the eigenvector of , and V is a diagonal matrix formula composed of the eigenvalues of .

[0026] (5) ​

[0027] where, is the ith eigenvalue, r is the rank of the matrix. So the condition number of the matrix is formula (6):

[0028] (6)

[0029] The diagonal matrix composed of the eigenvalues of the matrix becomes formula (7):

[0030] (7)

[0031] The condition number of the matrix is formula (8):

[0032] (8)

[0033] It can be seen that after adding the damping factor, the condition number becomes smaller, the degree of ill-condition of the matrix is reduced, and the calculation accuracy is improved.

[0034] Select the middle and far offset traces with better multiple suppression to participate in AVA amplitude fitting calculation, get , and the fitting calculation formula is:

[0035] (m=0,1,2) (9)

[0036] On the basis of the fitting calculation formula, the amplitude value of the seismic trace at t time can be calculated approximately by formula (10). The amplitude value formula is:

[0037] (10)

[0038] According to the amplitude value, the theoretical seismic data without multiple waves is obtained (t).

[0039] The seismic data obtained by the amplitude value formula and and the original seismic data S, the mean are normalized and cross-correlation coefficient analysis is performed. The normalized cross-correlation coefficient G is defined as formula (11):

[0040] (11)

[0041] Formula (11) accurately describes the correlation between the calculated seismic data , , the original seismic data S, and the mean , and improves the normalized cross-correlation. The larger the calculated normalized cross-correlation coefficient value is, the higher the similarity between the calculated seismic trace and the actual seismic trace is.

[0042] After obtaining the normalized cross-correlation coefficient of the calculated seismic trace and the actual seismic trace, the formula The seismic data after suppressing the interbed multiple wave is reconstructed, so as to remove the interbed multiple wave of the land near trace:

[0043] .(12)

[0044] Further, a land interbed multiple wave suppression device is also provided, comprising:

[0045] The acquisition module is configured to acquire seismic data that needs to be subjected to land interbed multiple wave suppression.

[0046] The data processing module is configured to perform far trace noise cutting and random noise suppression on the seismic data.

[0047] The fitting module is configured to fit an amplitude curve by using a multiple wave removal middle-far offset.

[0048] The calculation module is configured to calculate theoretical seismic data, a normalized cross-correlation coefficient of the theoretical seismic data and the original seismic data, reconstruct data according to the normalized cross-correlation coefficient, and obtain seismic data after land interbed multiple wave suppression.

[0049] Further, an electronic device is also provided, comprising a processor and a memory, wherein the processor is configured to execute a land interbed multiple wave suppression program stored in the memory to implement the land interbed multiple wave suppression method described above.

[0050] Further, a storage medium is also provided, comprising one or more programs stored in the storage medium, wherein the one or more programs can be executed by one or more processors to implement the land interbed multiple wave suppression method described above.

[0051] Compared with the prior art, the present application has the advantages and positive effects that:

[0052] The present application provides a land interbed multiple wave suppression method, which uses AVA fitting and normalized cross-correlation coefficient to reconstruct data, suppresses land seismic near trace interbed multiple wave, and has AVO trend after suppressing interbed multiple wave, which is beneficial to the utilization of AVO technology on pre-stack near trace information; the data is denoised when calculating the data, which does not affect the lateral resolution, does not reduce the lateral resolution of the seismic wave, and does not lose high frequency information, so as to achieve the purposes of removing near trace interbed multiple wave and improving the signal-to-noise ratio of the seismic data; the damping least square method is used to solve the coefficients of the polynomial, so as to reduce the degree of the ill-conditioned matrix and improve the calculation accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0054] Figure 1 A flowchart of a land interlayer multiple wave suppression method provided by the embodiments of the present application;

[0055] Figure 2 Data in which land seismic near trace exists interlayer multiple wave in the embodiments of the present application;

[0056] Figure 3 Effect after the land interlayer multiple wave suppression method is applied in the embodiments of the present application;

[0057] Figure 4 Suppressed near trace interlayer multiple wave in the embodiments of the present application;

[0058] Figure 5 A land interlayer multiple wave suppression device in the embodiments of the present application;

[0059] Figure 6 A structural schematic diagram of an electronic device in the embodiments of the present application. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present application.

[0061] In order to facilitate the understanding of the embodiments of the present application, the following will be further explained and described in combination with specific embodiments by the drawings. The embodiments do not constitute a limitation on the embodiments of the present application.

[0062] Embodiment one:

[0063] Referring to Figures 1-4 The present application provides a land interlayer multiple wave suppression method, characterized in that, comprising:

[0064] S11, acquiring seismic data which needs to be subjected to land interlayer multiple wave suppression;

[0065] S12, performing far trace noise cutting and random noise suppression on the seismic data to obtain denoised data;

[0066] S13, based on the de-noising data, using multiple wave removal in far offset fitting amplitude curve, according to the amplitude curve approximate calculation of a theoretical seismic data does not contain multiple wave;

[0067] S14, calculating the normalized cross-correlation coefficient of the theoretical seismic data and the original seismic data;

[0068] S15, according to the normalized cross-correlation coefficient, data reconstruction is obtained after land interlayer multiple wave suppression seismic data.

[0069] The seismic data that needs to be suppressed by land interlayer multiple wave is time domain or depth domain common imaging point seismic data.

[0070] The far path noise cut is cut by using two-way reflection travel time and offset data pair.

[0071] On the basis of common imaging point seismic data cut, the random noise suppression is carried out. Using random noise suppression method, denoising without loss of high frequency information, without reducing the lateral resolution, further suppressing random noise, improving the signal to noise ratio.

[0072] The relationship between the sampling value of the seismic signal at any t time in the common imaging point seismic data and the offset is represented by a polynomial;

[0073] The polynomial is: ; (1)

[0074] In the formula is the offset of the i th path; is the amplitude value of the i th path at t time; is a constant; is the high order error.

[0075] The polynomial ignores the high order error, which can be expressed by vector matrix formula, specifically:

[0076] (2)

[0077] The coefficients of the polynomial are solved by using the damped least square method;

[0078] Specifically, the objective function is constructed, and the vector matrix formula can also be written as

[0079] ; (3)

[0080] At the minimum value of the objective function, that is, The least square estimation formula of the coefficients of the polynomial is obtained: ; (4)

[0081] where ;

[0082] The advantage of using the damped least square method to solve the polynomial coefficients is that is a symmetric positive definite matrix, so it can be orthogonally decomposed as where R is the eigenvector of , and V is the diagonal matrix composed of the eigenvalues of The formula is:

[0083] (5)

[0084] where is the ith eigenvalue, and r is the rank of the matrix. Therefore, the condition number of the matrix is formula (6):

[0085] (6)

[0086] The diagonal matrix composed of the eigenvalues of becomes formula (7):

[0087] (7)

[0088] The condition number of the matrix is formula (8):

[0089] (8)

[0090] It can be seen that after adding the damping factor, the condition number becomes smaller, the degree of ill-conditioning of the matrix is reduced, and the calculation accuracy is improved.

[0091] Select the middle and far offset traces with good multiple suppression to participate in AVA amplitude fitting calculation, get , and the fitting calculation formula is:

[0092] (m=0,1,2) (9)

[0093] On the basis of the fitting calculation formula, the amplitude value of the seismic trace at time t can be calculated approximately by formula (10), and the amplitude value formula is:

[0094] ; (10)

[0095] According to the amplitude value, the theoretical seismic data (t) without multiple waves is obtained.

[0096] The seismic data obtained by the amplitude value formula and The original seismic data S, the mean value The normalized cross-correlation coefficient analysis is performed, and the normalized cross-correlation coefficient G is defined as the formula:

[0097] (11)

[0098] The formula (11) accurately describes the correlation between the calculated seismic data 、 , the original seismic data S, and the mean value , and improves the normalized cross-correlation. The larger the calculated normalized cross-correlation coefficient value is, the higher the similarity between the calculated seismic trace and the actual seismic trace is.

[0099] After obtaining the normalized cross-correlation coefficient between the calculated seismic trace and the actual seismic trace, the formula is used to reconstruct the seismic data after suppressing inter-bed multiples, so as to achieve the purpose of removing the inter-bed multiples of the land near trace.

[0100] (12)

[0101] Specific embodiments: Figure 2 is the data of the land near trace with inter-bed multiples; Figure 3 is the effect after applying the land inter-bed multiple suppression method of the present application. As can be seen from Figure 3 , the pre-stack near trace inter-bed multiples are effectively suppressed. Figure 4 is the suppressed near trace inter-bed multiple. As can be seen from Figure 4 , the remaining inter-bed multiples after suppression do not have effective near trace seismic information, and have good amplitude preservation.

[0102] The method uses AVA fitting and normalized cross-correlation coefficient to reconstruct data, suppresses the land seismic near trace inter-bed multiples, and the same-phase axis amplitude after suppressing the inter-bed multiples has an AVO trend, which is beneficial to the utilization of AVO technology on the pre-stack near trace information; the data is denoised when calculating the data, and the denoising does not affect the lateral resolution, does not reduce the lateral resolution of the seismic wave, and does not lose high-frequency information, so as to achieve the purpose of removing the near trace inter-bed multiples and improving the signal-to-noise ratio of the seismic data; the damping least square method is used to solve the coefficients of the polynomial, so that the degree of illness of the matrix is reduced, and the calculation accuracy is improved.

[0103] Embodiment two:

[0104] Referring to Figure 5 , on the basis of embodiment one, a land inter-bed multiple suppression device capable of completing the land inter-bed multiple suppression method in embodiment one is further provided, which comprises:

[0105] The acquisition module 701 is configured to acquire seismic data requiring land interlayer multiple wave suppression;

[0106] The data processing module 702 is configured to perform far-offset noise cutting and random noise suppression on the seismic data;

[0107] The fitting module 703 is configured to fit an amplitude curve by using a middle-far offset in multiple wave removal;

[0108] The calculation module 704 is configured to calculate theoretical seismic data, a normalized cross-correlation coefficient of the theoretical seismic data and original seismic data, reconstruct data according to the normalized cross-correlation coefficient, and obtain land interlayer multiple wave suppressed seismic data.

[0109] Embodiment three:

[0110] Also provided is an electronic device including a processor and a memory, wherein the processor is configured to execute a land interlayer multiple wave suppression program stored in the memory to implement the land interlayer multiple wave suppression method described in embodiment one. Figure 6 The electronic device 800 shown includes at least one processor 801, a memory 802, at least one network interface 804, and other user interfaces 803. The various components in the electronic device 800 are coupled together by a bus system 805. It can be understood that the bus system 805 is used to realize the connection and communication between the components. In addition to including a data bus, the bus system 805 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, all the buses are marked as the bus system 805 in Figure 6 .

[0111] The user interface 803 can include a display, a keyboard, or a pointing device (for example, a mouse, a trackball, a touchpad, or a touch screen, etc.).

[0112] It can be understood that the memory 802 in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. The non-volatile memory can be a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, or a flash memory. The volatile memory can be a random access memory, which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory, dynamic random access memory, synchronous dynamic random access memory, double data rate synchronous dynamic random access memory, enhanced synchronous dynamic random access memory, synchronous link dynamic random access memory, and direct memory bus random access memory. The memory 802 described herein is intended to include but not limited to these and any other suitable types of memory.

[0113] In some embodiments, the memory 802 stores the following elements, executable units or data structures, or a subset of them, or an extended set of them: an operating system 8021 and application programs 8022.

[0114] The operating system 8021 includes various system programs, such as a framework layer, a core library layer, a driver layer, etc., for implementing various basic services and processing hardware-based tasks. The application programs 8022 include various application programs, such as a media player, a browser, etc., for implementing various application services. The programs for implementing the method embodiments of the present application can be included in the application programs 8022.

[0115] In the embodiments of the present application, the processor 801 is configured to execute the method steps provided by each method embodiment by invoking the programs or instructions stored in the memory 802, in particular, the programs or instructions stored in the application programs 8022.

[0116] Embodiment four:

[0117] A storage medium is also provided, which includes one or more programs stored thereon, which can be executed by one or more processors to implement the land interlayer multiple wave suppression method described in embodiment one.

[0118] The steps of the methods or algorithms described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in random access memory, flash memory, read-only memory, electrically programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0119] The above detailed description sets forth the purposes, technical solutions, and beneficial effects of the present application. It should be understood that the above is only a specific implementation of the present application, and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for land interbed multiple wave suppression, characterized in that, The method comprises the following steps: acquiring seismic data requiring land interlayer multiple wave suppression; performing far-offset noise cutting and random noise suppression on the seismic data to obtain denoised data; fitting an amplitude curve based on the denoised data by using mid-far offset data with better multiple wave suppression, and approximately calculating a theoretical seismic data without multiple waves according to the amplitude curve; calculating a normalized cross-correlation coefficient of the theoretical seismic data and the original seismic data; performing data reconstruction according to the normalized cross-correlation coefficient to obtain seismic data after land interlayer multiple wave suppression.

2. The land interbed multiple wave suppression method according to claim 1, characterized by, The seismic data requiring land interlayer multiple wave suppression is common imaging point seismic data in time domain or depth domain.

3. The land interbed multiple wave suppression method according to claim 1 or 2, characterized by, The far-offset noise cutting is performed by using two-way reflection travel time and offset data to form a cutting line, and the common imaging point seismic data is cut outside.

4. The land interbed multiple wave suppression method according to claim 3, characterized in that, The random noise suppression is performed on the basis of the cutting outside the common imaging point seismic data.

5. The method of claim 2, wherein, The relationship between the sampling value of the seismic signal at any t time and the offset in the common imaging point seismic data is represented by a polynomial; The polynomial is: ; In the formula is the offset distance of the ith track; is the amplitude value of the ith track at time t; is a constant coefficient; is a high-order term error.

6. The land interbed multiple wave suppression method according to claim 5, characterized in that, the coefficients of the polynomial are solved by using a damped least square method; Specifically: construct a target function; at the minimum value of the target function, obtain the least square estimation formula of the coefficients of the polynomial: .

7. The land interbed multiple wave suppression method according to claim 6, characterized by, mid-far offset traces with better multiple wave suppression are selected to participate in amplitude fitting calculation, and the fitting calculation formula is: m=0,1,2。 8. The land interbed multiple wave suppression method according to claim 7, characterized by, The seismic data obtained from the amplitude value formula and The normalized cross-correlation coefficient analysis is performed on the original seismic data S, the mean value The normalized cross-correlation coefficient G is defined as the formula: Using the formula Reconstructing the seismic data after suppressing interbed multiples: 。 9. A device for suppressing land interbed multiple based on the method of claim 1, characterized in that, The method comprises the following steps: an acquisition module, configured to acquire seismic data requiring land interlayer multiple wave suppression; a data processing module, configured to perform far-offset noise cutting and random noise suppression on the seismic data; a fitting module, configured to fit an amplitude curve by using mid-far offset data with better multiple wave suppression; a calculation module, configured to calculate a theoretical seismic data, a normalized cross-correlation coefficient of the theoretical seismic data and the original seismic data, and perform data reconstruction according to the normalized cross-correlation coefficient to obtain seismic data after land interlayer multiple wave suppression.

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