A method for suppressing linear interference waves of a seismic shot gather
By using Radon transform and filtered back projection, the special linear interference waves in the seismic shot concentration were accurately separated, solving the frequency-wavenumber domain overlap problem and improving the signal-to-noise ratio and imaging accuracy of seismic exploration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI UNIV OF SCI & TECH
- Filing Date
- 2026-04-22
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies struggle to effectively separate special linear interference waves that completely overlap with the effective wave in the frequency-wavenumber domain. Conventional filtering methods result in effective wave loss or interference wave residue, reducing the signal-to-noise ratio and imaging accuracy of seismic exploration results.
By employing Radon transform and filtered back projection, special linear interference waves are highlighted through high-pass filtering. The tilt angle parameters are calculated, Radon transform is performed, and then zeroed out. Inverse transform is then performed using filtered back projection to accurately separate and suppress special linear interference waves.
It achieves precise separation of special linear interference waves, recovers buried effective signals, significantly improves signal-to-noise ratio and imaging accuracy, and optimizes the quality of seismic exploration results.
Smart Images
Figure CN122194302A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of seismic shot gather data processing, and particularly relates to a method for suppressing linear interference waves from seismic shot gathers. Background Technology
[0002] In seismic exploration data processing, various linear interference waves often accompany seismic shot gathers. While conventional interferences such as surface waves and direct waves can be effectively suppressed by existing methods, there is a special type of linear interference wave whose dominant frequency and dip angle are highly similar to those of the effective wave over a large offset range. In the frequency and wavenumber (FK) domains, it completely overlaps with the effective wave, and conventional FK filtering and related methods cannot achieve accurate separation between the two.
[0003] Conventional interference suppression methods can only handle this type of special interference in a coarse manner. Strong filtering will cause a large loss of effective waves, while weak filtering cannot completely eliminate the interference. Moreover, this interference is often buried by high-energy surface waves, making it difficult to accurately identify and pick up parameters. Ultimately, this significantly reduces the signal-to-noise ratio and imaging accuracy of seismic exploration results. There is a lack of targeted and efficient separation and suppression technologies in the industry. Summary of the Invention
[0004] In view of the aforementioned problems, and in conjunction with the first aspect of the present invention, embodiments of the present invention provide a method for suppressing linear interference waves from a seismic shot gather, the method comprising: Includes the following steps: Step S1: Read in the raw seismic shot gather data; Step S2: Perform a high-pass filter of 10Hz or higher on the original seismic shot gather data to filter out surface waves and highlight special linear interference waves; Step S3: Calculate the tilt angle parameters along the direction of the special linear interference wave for the filtered data, and determine the rotation angle required for the Radon transform; Step S4: Perform a Radon transformation on the original seismic shot gather data, and set the Radon domain energy values within each preset angle range to 0 on the left and right of the rotation angle; Step S5: Perform the inverse Radon transform on the Radon domain data after setting it to 0 using the filtered back projection method; Step S6: Output the seismic shot gather data after suppressing the special linear interference wave.
[0005] Preferably, in step S3, angle parameters in at least two directions are picked up; the angle parameters of the same type of special linear interference wave can be reused in multiple seismic shot collections.
[0006] Preferably, in step S3, the rotation angle is the angle perpendicular to the direction of the special linear interference wave.
[0007] Preferably, in step S4, the preset angle is 10 degrees, that is, the energy value of the Ladon domain within a 10-degree range to the left and right of the picked rotation angle is set to 0.
[0008] Preferably, the Radon transform involves converting seismic shot gather data into a two-dimensional image matrix and calculating the line integral projection of the parallel ray beam along a specified angle.
[0009] Preferably, in step S5, the filtered back projection method performs high-frequency compensation on the projection data in the frequency domain before performing the back projection operation.
[0010] Preferably, the original seismic shot gather data is in Segy format.
[0011] A system for suppressing linear interference waves from a seismic shot gather includes: The data reading module is used to read in the raw seismic shot gather data; The high-pass filter module is used to perform high-pass filtering of more than 10Hz on the raw seismic shot gather data to filter out surface waves and highlight special linear interference waves; The parameter acquisition module is used to calculate the tilt angle parameter of the filtered data along the direction of a special linear interference wave, and to determine the rotation angle required for the Radon transform. The Radon transformation processing module is used to perform Radon transformation on the original seismic shot gather data and set the Radon domain energy value to 0 within each preset angle range to the left and right of the rotation angle. The inverse transform module is used to perform the inverse Radon transform on the Radon domain data after it has been set to zero using the filtered inverse projection method. The results output module is used to output the seismic shot gather data after suppressing special linear interference waves.
[0012] Preferably, the parameter picking module is configured to pick up angle parameters in at least two directions, and the angle parameters of the same type of special linear interference wave can be reused in multiple seismic shot sets.
[0013] Preferably, the preset angle in the Radon transformation processing module is 10 degrees.
[0014] Based on the above, the precise separation of special linear interference waves and effective waves is achieved by relying on Radon transform, which fundamentally solves the problem that the two are completely superimposed in the FK domain and cannot be distinguished and processed. The target interference can be completely eliminated by setting the directional angle to zero, avoiding the large loss of effective waves caused by conventional strong filtering.
[0015] This method relies on precise parameter picking and filtered back projection to efficiently complete the inverse transformation while simultaneously suppressing high-frequency noise, random noise, and some direct waves, allowing the effective signals buried by interference to be fully recovered. This significantly improves the signal-to-noise ratio of the seismic shot gather and the continuity of the effective wave phase axis, greatly optimizing the imaging accuracy and data quality of seismic exploration results. Attached Figure Description
[0016] Figure 1This is a basic flowchart illustrating the method for suppressing special linear interference waves from a seismic shot gather.
[0017] Figure 2 Original shot gather and FK spectrum containing surface waves and special linear interference waves; (a) Original shot gather; (b) FK spectrum of original shot gather.
[0018] Figure 3 Shot set processed by strong FK filtering.
[0019] Figure 4 Shot gathers that remove special linear interference waves that are prominent in surface waves (for parameter picking and analysis only). Figure 5 The Radon transform diagram of the original shot set and the identification area of special linear interference.
[0020] Figure 6 Interference waves removed by Radon transform (including special linear interference waves, some surface waves, single-frequency interference, and shallow direct waves).
[0021] Figure 7 Shot gather after special linear interference suppression (surface waves not removed). Figure 8 Shot gather after special linear interference and surface wave suppression.
[0022] Figure 9 This is a schematic diagram illustrating the principle. Detailed Implementation
[0023] The invention will now be described in detail with reference to the accompanying drawings. The method for suppressing linear interference waves from the seismic shot collection will be described in detail below.
[0024] The purpose of this invention is to propose a method for suppressing special linear interference waves from seismic shot gathers. This invention utilizes the Radon transform to transform the shot gather into the Radon domain. The processed shot gather, highlighting the special linear interference, is used to accurately extract angle parameters. These parameters are then applied to the Radon domain to precisely identify the distribution area of the special linear interference waves. The identified area is then set to zero. Finally, a filtered back-projection method is applied to perform an inverse Radon transform, which completely separates and suppresses these special linear interference waves.
[0025] The implementation steps are: Step 1: Read in the raw seismic shot gather data; Step 2: Apply a high-pass filter of 10Hz or higher to the seismic shot gather to filter out surface waves on the shot gather and highlight special linear interference waves so as to pick up angle parameters. Step 3 calculates the tilt angle parameters along the specific linear interference direction of the filtered data from Step 2 for the next step of processing. The tilt angle perpendicular to the direction of interference is the rotation angle required for the Radon transform. Typically, picking the angle parameters in two directions is sufficient. For a specific type of interference, only one parameter picking is needed, which can be applied to multiple shot collections. Step 4 performs Radon transform on the raw data input in Step 1, and sets the Radon domain energy value within a range of approximately 10 degrees to the left and right of the angle parameter picked in Step 2 to 0, which is equivalent to removing the energy of the special frequency linear interference projection. Step 5 uses the filtered back projection method to perform the inverse Radon transform on the Radon domain data after setting it to 0; Step 6: Obtain seismic shot gather data for suppressing specific linear interference waves. This invention is particularly effective in suppressing linear interference waves in seismic shot gathers whose dip angle, dominant frequency, and effective wave frequency are approximately the same.
[0026] Step 1 involves reading in the original seismic shot gather data.
[0027] Step 2 involves applying a high-pass filter of 10Hz or higher to the seismic shot gather to filter out surface waves on the shot gather and highlight special linear interference waves in order to pick up angle parameters.
[0028] Step 3 calculates the tilt angle parameters along the specific linear interference direction of the filtered data from step 2 for further processing. The tilt angle perpendicular to the direction of interference is the rotation angle required for the Radon transform. Typically, picking the angle parameters in two directions is sufficient. For a specific type of interference, only one parameter picking is needed, which can be applied to multiple shot collections.
[0029] After the seismic shot gather is read into the two-dimensional array, the increments in both the longitudinal and transverse directions are 1. The angle parameters are calculated by picking the straight line along the linear disturbance.
[0030] Step 4 performs a Radon transformation on the original data input in Step 1, and sets the Radon domain energy value within a range of approximately 10 degrees to the left and right of the angle parameter picked in Step 2 to 0, which is equivalent to removing the energy of the special frequency linear interference projection.
[0031] The image calculation method used in this Radon transform first writes the seismic data into a two-dimensional image matrix, and then calculates the projection according to a specified method.
[0032] The Radon projection is a series of line integrals of a two-dimensional function F(x,y), calculated along a specified direction from multiple parallel path beams from the source to the receiver. The spacing between parallel lines is sampled at one-pixel intervals. The Radon transform employs projections from multiple parallel ray beams at different angles, with the angle parameters obtained by rotating the source position around the image center. A projection with a specified rotation angle can be described schematically. Here, θ is the rotation angle, x and y represent the abscissa and ordinate, respectively, and F(x,y) represents the amplitude value of the shot in the coordinate system.
[0033] The projection is calculated along angle θ, typically using the Radon transform of the function F(x,y) as a line integral parallel to the y' axis: ; here: ; Where x' and y' represent x and y after rotation in the coordinate system, respectively. Let F(x,y) be the Radon transform.
[0034] Step 5 uses the filtered back projection method to perform a reverse transformation on the Radon domain data after setting it to 0.
[0035]
[0036] Unfiltered backprojection essentially applies a strong low-pass filter to the reconstructed image. This means compressing high frequencies and amplifying low frequencies in the frequency domain, resulting in a blurred reconstructed image. Since the problem lies in the weakening of high-frequency information, the most natural solution is to compensate for the high frequencies during the reconstruction process. This is the core idea of filtered backprojection: first, perform high-frequency compensation (filtering) on each projection in the frequency domain, and then perform backprojection to obtain a higher-quality projection effect.
[0037] Step 6 involves acquiring seismic shot gather data that suppresses special linear interference waves.
[0038] In summary, this invention discloses a method for suppressing special linear interference waves from seismic shot assemblies. When the dominant frequency and dip angle of the linear interference wave are close to those of the effective wave in the local offset segment (usually in the large offset segment), it completely overlaps with the effective wave in the frequency-wavenumber (FK) domain. In the frequency-wavenumber (FK) domain, it can only be retained or eliminated simultaneously. Currently, conventional methods struggle to accurately separate and suppress this special linear interference wave from the shot assemblies. This invention employs a combination of targeted Radon transform, efficient inverse transform, and precise parameter picking to effectively separate and eliminate special linear interference waves whose dominant frequency and dip angle overlap with the effective wave. The invention has the following outstanding advantages: The Radon transform was used to enable the linear interference wave with a main frequency and tilt angle close to the effective wave to be accurately separated from the effective wave in the Radon domain, thus avoiding the problem of complete overlap in the frequency and wavenumber domains. De-surface processing is performed during parameter picking to make the angle parameters more accurate. The inverse Radon transform is performed using the filtered back projection method, which improves the computational efficiency, restores the image with high accuracy, and avoids image blurring. Interpolation and special filtering are applied during the inverse transform to suppress some high-frequency and random noise. In addition, some direct waves that coincide with the distribution of special linear interference waves are also suppressed. Therefore, the signal-to-noise ratio of the shot gather is significantly improved after processing. The combination of targeted Radon transform, efficient inverse transform, and parameter picking accuracy results in excellent final processing performance.
[0039] To make the technical solution and advantages of the present invention clearer, the implementation method of the present invention for suppressing special linear interference waves from seismic shot assemblies will be described in more detail below. Figure 1 This is a basic flowchart of the implementation of the method of the present invention.
[0040] Step S101 reads in the raw seismic shot gather data. In seismic exploration, the raw shot gather data is usually stored in Segy format.
[0041] Step S102 applies a high-pass filter of 10Hz or higher to the seismic shot gather to filter out surface waves and highlight special linear interference waves for angular parameter acquisition. The dominant frequency of surface wave interference in the seismic shot gather is generally between 5-10Hz, and different excitation lithologies and excitation conditions have a certain influence on it.
[0042] Step S103 calculates the tilt angle parameters along the specific linear interference direction of the filtered data from step 102 for the next step of processing. The tilt angle is perpendicular to the direction of the interference and is the rotation angle required for the Radon transform. Typically, picking the angle parameters in two directions is sufficient. For a specific type of interference, only one parameter picking is needed, which can be applied to multiple shot collections.
[0043] Step S104 performs Radon transformation on the original data input in step 101, and sets the Radon domain energy value within a range of approximately 10 degrees to the left and right of the angle parameter picked in step 102 to 0, which is equivalent to removing the energy of the special frequency linear interference projection.
[0044] Step S105 uses the filtered back projection method to perform a Radon inverse transformation on the Radon domain data after setting it to 0.
[0045] Step S106: Obtain seismic shot gather data to suppress special linear interference waves.
[0046] Figure 2The image shown (a) depicts the original shot gather and its FK spectrum, which includes surface waves and special linear interference waves. The linear interference waves in this original shot gather are mainly of three types: direct wave interference, surface wave interference, and special linear interference waves. Direct wave interference and surface waves are common interference waves and can be easily handled using existing methods. The special interference waves studied in this patent are difficult to suppress due to their unique frequency and dip angle. They are usually buried beneath surface waves in the shot gather, appearing low in energy but actually possessing very high energy. Incomplete suppression of these interference waves can significantly impact the final results. Furthermore, effective waves often exist beneath these high-energy interference waves. If this special linear interference is effectively suppressed, the effective signal can be recovered, thus improving the quality of the final results. Figure 2 b. The FK spectrum of the original shot gather shows that the surface wave is clearly distributed outside the lower frequency region, and the special linear interference is superimposed with the effective wave without a clear boundary.
[0047] Figure 3 The shot gather processed by the strong FK filter shown in the image has its special interference waves suppressed. However, due to the strong FK filter, a large portion of the effective waves are also removed at the same time. This result clearly does not meet the processing requirements.
[0048] Figure 4 This image shows a shot gather after removing surface wave interference to highlight specific linear interference waves. This image is for parameter picking and analysis only. After surface wave processing, the specific linear interference is prominently displayed. As seen in the image, this specific linear interference wave has strong energy and good linearity. However, in the original shot gather, it is buried by low-frequency, high-energy surface waves, appearing weaker. After processing, some effective waves are also clearly visible. The two rectangles connected by arrows in the image represent the effective wave and the specific linear interference wave, respectively. The effective wave in the shallow to mid-depth section with a large offset is clearly visible in this image. Its frequency and dip angle are very close to the specific linear interference wave caused by strong mechanical vibration, but it is difficult to clearly show in the original shot gather. In the frequency-wavenumber domain (FK), these two waves completely overlap and cannot be separated.
[0049] Figure 5 This image shows the Radon transform diagram of the original gun collection and the identification region for special linear interference. After the Radon transform, the horizontal axis represents the projection angle from 0 to 180 degrees (symmetrical to 181 to 360 degrees), and the vertical axis represents the position. Each point in the image represents the projected energy at different positions from different angles. The center of the image is used as the center of the coordinate system during the transform. The angular range of the zero-value region in the image is... Figure 2 The angle calculated is formed by expanding it by 10 degrees to the left and right. The main reason for this is that the tilt angle of the linear interference wave in reality is not completely consistent. It has a certain range. The calculated angle parameter is the center position. In application, it is necessary to offset it by a certain angle to the left and right in order to completely cover the linear interference wave.
[0050] Figure 6 Interference waves removed by the Radon transform method include special linear interference waves, some surface waves, single-frequency interference, and shallow direct waves.
[0051] Figure 7 For shot collections after special linear interference suppression, surface waves are not removed. However, surface waves can be removed using conventional methods.
[0052] Figure 8 For shot gathers after special linear interference and surface wave suppression, the final processing results show that the special linear interference wave with a dominant frequency and tilt angle close to the effective wave is completely suppressed. After the special interference wave is removed, the part of the effective wave buried by it is also clearly visible. Although its energy is not strong, its continuity and consistency are very good. After multiple overlays, the continuity of the phase axis of the effective wave in the interference area will be greatly enhanced, which can effectively improve the quality of the final result.
[0053] It should be noted that, in order to simplify the description of the present invention and thus help to understand one or more embodiments of the invention, multiple features may sometimes be grouped into one embodiment, drawing or description thereof in the foregoing description of the embodiments of the present invention.
[0054] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.
Claims
1. A method for suppressing linear interference waves from a seismic shot gather, characterized in that: Includes the following steps: Step S1: Read in the raw seismic shot gather data; Step S2: Perform a high-pass filter of 10Hz or higher on the original seismic shot gather data to filter out surface waves and highlight special linear interference waves; Step S3: Calculate the tilt angle parameters along the direction of the special linear interference wave for the filtered data, and determine the rotation angle required for the Radon transform; Step S4: Perform a Radon transformation on the original seismic shot gather data, and set the Radon domain energy values within each preset angle range to 0 on the left and right of the rotation angle; Step S5: Perform the inverse Radon transform on the Radon domain data after setting it to 0 using the filtered back projection method; Step S6: Output the seismic shot gather data after suppressing the special linear interference wave.
2. The method for suppressing linear interference waves from a seismic shot gather according to claim 1, characterized in that: In step S3, at least two angular parameters are picked up; the angular parameters of the same type of special linear interference wave can be reused in multiple seismic shot gathers.
3. The method for suppressing linear interference waves from a seismic shot gather according to claim 1, characterized in that: In step S3, the rotation angle is the angle perpendicular to the direction of the special linear interference wave.
4. The method for suppressing linear interference waves from a seismic shot gather according to claim 1, characterized in that: In step S4, the preset angle is 10 degrees, that is, the energy value of the Ladon domain within a 10-degree range to the left and right of the picked rotation angle is set to 0.
5. The method for suppressing linear interference waves from a seismic shot gather according to claim 1, characterized in that: The Radon transform converts seismic shot gather data into a two-dimensional image matrix and calculates the line integral projection of parallel ray beams along a specified angle.
6. The method for suppressing linear interference waves from a seismic shot gather according to claim 1, characterized in that: In step S5, the filtered back projection method performs high-frequency compensation on the projection data in the frequency domain before performing the back projection operation.
7. The method for suppressing linear interference waves from a seismic shot gather according to claim 1, characterized in that: The original seismic shot gather data is in Segy format.
8. A system for suppressing linear interference waves from a seismic shot gather, based on the method for suppressing linear interference waves from a seismic shot gather according to any one of claims 1-7, characterized in that: include: The data reading module is used to read in the raw seismic shot gather data; The high-pass filter module is used to perform high-pass filtering of more than 10Hz on the raw seismic shot gather data to filter out surface waves and highlight special linear interference waves; The parameter acquisition module is used to calculate the tilt angle parameter of the filtered data along the direction of a special linear interference wave, and to determine the rotation angle required for the Radon transform. The Radon transformation processing module is used to perform Radon transformation on the original seismic shot gather data and set the Radon domain energy value to 0 within each preset angle range to the left and right of the rotation angle. The inverse transform module is used to perform the inverse Radon transform on the Radon domain data after it has been set to zero using the filtered inverse projection method. The results output module is used to output the seismic shot gather data after suppressing special linear interference waves.
9. A system for suppressing linear interference waves from a seismic shot gather according to claim 8, characterized in that: The parameter picking module is configured to pick up angle parameters in at least two directions. The angle parameters of the same type of special linear interference wave can be reused in multiple seismic shot gathers.
10. A system for suppressing linear interference waves from a seismic shot gather according to claim 8, characterized in that: The preset angle in the Radon transformation processing module is 10 degrees.