Method for multiple wave suppression of seabed node data and medium

Abstract

The application discloses a method for multiple wave suppression of seabed node data and a medium, and comprises the following steps: S1, acquiring towed cable data and seabed node data of seabed monitoring, and matching and sorting the towed cable data and the seabed node data; S2, extracting the matched and sorted towed cable data and seabed node data for multidimensional space convolution processing to obtain a multiple wave model gather; and S3, subtracting the multiple wave model gather from the seabed node data to obtain seabed node data with suppressed multiple waves, so that the multiple wave suppression is realized. The application is suitable for all seawater depths and seabed conditions through the monitoring of the towed cable data and the seabed node data, then the prediction rate is improved through the multidimensional space convolution processing of the towed cable data and the seabed node data, and finally the multiple wave suppression effect is improved through the subtraction of the multiple wave model gather, so that the calculation amount of the assumed seawater depth and seabed condition is reduced, and the multiple wave suppression rate and effect of the seabed node data are improved.

Description

Technical Field

[0001] This invention relates to the field of geophysical exploration technology, and in particular to a method and medium for suppressing multiple waves in seabed node data. Background Technology

[0002] Seafloor nodal (OBN) data is increasingly used due to its advantages such as multi-component, omnidirectional, high coverage, and long offset. In data processing, the comprehensive information received by OBN data has promoted the application of new technologies, such as vector slice processing technology adapted to wide azimuth angles, full waveform inversion modeling technology for long offsets, and five-dimensional seismic interpretation technology, which have comprehensively improved the accuracy of velocity modeling, seismic imaging quality, trap characterization, and reservoir prediction. However, due to the difference in the receiving methods, the shot and receiver points are not on the same plane, which brings new processing problems. In particular, when using feedback iteration methods for multiple wave prediction and suppression, it is impossible to accurately predict the arrival time and energy of multiple waves using OBN data.

[0003] Currently, industry practices generally fall into three categories: The first category utilizes conventional seabed multiple suppression methods. These methods, developed for towed cable data, have achieved some success with seabed node data, but they fail in deep water conditions. The second category leverages the multi-component acquisition characteristics of seabed node data. By merging land and water data to separate uplink and downlink wavefields, deconvolution of the uplink and downlink wavefields is used to suppress multiples in the uplink wavefield. However, this method relies on the assumption of a flat seabed and requires high-density data interpolation, resulting in massive computational demands. The third category extends the wavefield of the seabed node data received from the seabed to the water surface and then uses a feedback iteration method for multiple prediction and suppression. This approach encounters significant problems such as grid dispersion when seabed node sampling is sparse and the water depth is large. In short, existing technologies have poor performance and high computational demands for predicting and suppressing multiples from seabed node data at greater depths. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address at least one defect of the related technologies mentioned in the background art: the low effect and rate of multiple wave suppression of seabed node data, and to provide a method and medium for suppressing multiple waves of seabed node data.

[0005] The technical solution adopted by this invention to solve its technical problem is: to construct a method for suppressing multiple waves from seabed node data. The method includes the following steps: S1: acquiring towed cable data and seabed node data from seabed monitoring, and matching and sorting the towed cable data and seabed node data; S2: extracting the matched and sorted towed cable data and seabed node data and performing multidimensional spatial convolution processing to obtain a multiple wave model gather; S3: subtracting the multiple wave model gather from the seabed node data to obtain the seabed node data for suppressing multiple waves.

[0006] In some embodiments, in step S1, the towed cable data and seabed node data are matched and sorted according to the following steps: S11: The towed cable data is corrected by the seabed node data to obtain the matched towed cable data; S12: The matched towed cable data and seabed node data are extracted according to the shot point number and the receiver point number as index words to obtain the sorted towed cable dataset and the seabed node dataset.

[0007] In some embodiments, step S11 includes: S111: performing time difference correction on towed cable data using seabed node data as a standard; S112: selecting towed cable overlay data and seabed node overlay data in areas with a signal-to-noise ratio higher than a preset threshold within the survey area, comparing the towed cable overlay data and seabed node overlay data using the least squares method to obtain a matching factor; S113: performing matched filtering processing on towed cable data that has not undergone time difference correction based on the matching factor.

[0008] In some embodiments, the matching factor includes at least an amplitude matching factor, a frequency matching factor, and a phase matching factor.

[0009] In some embodiments, step S12 includes: extracting the matched towed cable data into common-shot-point towed cable data using the shot point number as the first index and the receiver point number as the second index; and extracting the seabed node data into common-receiver-point seabed node data using the receiver point number as the first index and the shot point number as the second index.

[0010] In some embodiments, the seabed node data extracted in step S12 is the upflow wave data of the seabed node data.

[0011] In some embodiments, in step S2, the multidimensional spatial convolution processing method is as follows: in, For seabed node data of the common detection points, For common shot point tow cable data, m is the multiple wave model gather generated after convolution. and These are the x and y coordinates of the spatial location of the receiver point, respectively. and These are the x and y coordinates of the spatial location of the shot point, respectively. and , , represent the x and y coordinates of the possible downstream reflection points of the seismic waves, respectively, and t is the propagation time of the seismic wave from excitation to reception.

[0012] In some embodiments, step S3 includes: subtracting the adaptive amplitude and phase-matched multiple wave model gather and the common receiver point seabed node data from the seabed node data to obtain the common receiver point seabed node data for suppressing multiple waves.

[0013] In some embodiments, the subtraction of multiple wave model gathers and common receiver point seabed node data from seabed node data is performed in the time-space domain or in the curve wave domain.

[0014] The present invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the multiple wave suppression method for seabed node data as described in any of the above embodiments.

[0015] By implementing this invention, the following beneficial effects are achieved: This invention adapts to all seawater depths and seabed conditions by monitoring towed cable data and seabed node data. Then, it improves the prediction rate through multidimensional spatial convolution processing of towed cable data and seabed node data. Finally, it improves the multiple wave suppression effect by subtracting multiple wave model gathers, thereby reducing the computational workload of assuming seawater depth and seabed conditions, and realizing the improvement of multiple wave suppression rate and effect in seabed node data. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 A flowchart of one embodiment of the method for suppressing multiple waves of seabed node data according to the present invention is shown; Figure 2 The flowchart of step S1 in an embodiment of the method for suppressing multiple waves of seabed node data of the present invention is shown; Figure 3 The flowchart of step S11 in an embodiment of the method for suppressing multiple waves of seabed node data of the present invention is shown; Figure 4 This paper illustrates a schematic diagram of the joint spatial convolution of towed cable data and seabed node (OBN) data in an embodiment of the multiple wave suppression method for seabed node data of the present invention. Figure 5-A A schematic diagram of the upflow wave profile of a seabed node without applying the multiple wave suppression method for seabed node data of the present invention is shown. Figure 5-B This diagram illustrates an embodiment of the multiple wave suppression method for seabed node data of the present invention, showing a schematic cross-section of the upflowing wave at a seabed node. Figure 6 The diagram shows an upflow wave profile spectrum of a seabed node in an embodiment of the multiple wave suppression method for seabed node data according to the present invention. Detailed Implementation

[0017] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0018] It should be noted that the flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0019] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0020] like Figure 1 As shown, this invention discloses a method for suppressing multiple waves in seabed node data, which includes the following steps: S1: Acquire towed cable data and seabed node data from seabed monitoring, and match and sort the towed cable data and seabed node data.

[0021] The towed cable data is acquired by an ocean towed cable seismic acquisition system, specifically by receiving seismic wave signals emitted by an air gun that penetrate the seabed and return. Ocean Bottom Node (OBN) data is acquired by a multi-component seismograph placed on the seabed, capable of independently acquiring and recording seismic wave signals. The multiple wave suppression of the ocean Bottom Node data in this invention is driven by the data itself, based on both the towed cable data and the ocean Bottom Node data. This avoids the need for modeling and assuming parameters such as seawater velocity, seabed reflection coefficient, and water depth. Therefore, it is fundamentally unaffected by changes in water depth and the complexity of seabed conditions, and can adapt to all water depths and seabed conditions.

[0022] like Figure 2 As shown, in some embodiments, in step S1, the towed cable data and seabed node data are matched and sorted according to the following steps: S11: The towed cable data is corrected by the seabed node data to obtain the matched towed cable data.

[0023] like Figure 3 As shown, in some embodiments, step S11 includes: S111: Time difference correction of towed cable data based on seabed node data.

[0024] The different observation systems used for the two acquisition methods, towed cable data and seabed node data, result in systematic differences in the time reference of seismic wave records. Therefore, it is necessary to use one set of data as a standard to correct the time difference and improve the accuracy of subsequent time-alignment-dependent matched filtering processing.

[0025] S112: Select towed cable overlay data and seabed node overlay data from areas within the survey area where the signal-to-noise ratio is higher than a preset threshold, and compare the towed cable overlay data and seabed node overlay data using the least squares method to obtain the matching factor.

[0026] By selecting areas within the survey area where the signal-to-noise ratio is higher than a preset threshold, it is possible to ensure that the matching factor can accurately reflect the systematic differences in effective signals between towed cable data and seabed node data due to different acquisition methods when calculating the matching factor using the least squares method, rather than being biased by local noise. This ensures the effectiveness and reliability of matched filtering processing throughout the entire survey area.

[0027] S113: Perform matched filtering on the uncorrected tow cable data based on the matching factor.

[0028] Matched filtering is applied to uncorrected towed cable data to avoid distortion caused by double correction. Time correction alters the relative positions of seismic traces on the time axis to achieve time alignment. Matched filtering, using a matching factor, modifies the amplitude / frequency of data that has already been stretched or compressed on the time axis, i.e., waveform alignment, resulting in double correction of the towed cable data. Applying matched filtering to uncorrected towed cable data avoids mutual interference and coupling errors between time alignment and waveform alignment.

[0029] In some embodiments, the matching factor includes at least an amplitude matching factor, a frequency matching factor, and a phase matching factor.

[0030] By matching the amplitude matching factor, frequency matching factor, and phase matching factor, the amplitude, frequency, and phase differences between towed cable data and seabed node data are eliminated, improving overall consistency and achieving uniformity of amplitude, frequency, and phase between towed cable data and seabed node data.

[0031] S12: Extract the dataset from the matched towed cable data and seabed node data using the shot point number and receiver point number as index words to obtain the sorted towed cable dataset and seabed node dataset.

[0032] The shot point number is a unique identifier for the location where the laser energy of the seismic source (air gun) is emitted; the detector point number is a unique identifier for the location of the seabed node that receives the reflected wave.

[0033] In some embodiments, step S12 includes: extracting the matched towed cable data into common-shot-point towed cable data with the shot point number as the first index and the receiver point number as the second index; and extracting the seabed node data into common-receiver-point seabed node data with the receiver point number as the first index and the shot point number as the second index.

[0034] During towed cable data acquisition, the shipborne seismic source (air gun) and the towed cable move forward together. Each time the shipborne seismic source fires a shot, all the detectors on the towed cable simultaneously receive data. Therefore, the common shot gather does not require any data rearrangement, saving significant computer rearrangement time. During seabed node data acquisition, the seabed nodes remain stationary. As the surface seismic source vessel continuously moves and fires shots, the same seabed node continuously receives signals from different azimuths and shot points. Therefore, the common detector gather exhibits a regular geometric relationship, which is beneficial for studies such as uplink and downlink wave separation of seabed node data.

[0035] In some embodiments, in step S12, the extracted seabed node data is the upflow wave data of the seabed node data.

[0036] Upward wave data from seafloor nodes refers to seismic wave signals propagating upward from the strata below the seafloor, recorded by seafloor nodes. Only upward wave data carries valid information about subsurface reflecting interfaces, and the extraction of common receiver gathers from upward wave data at seafloor nodes is to extract clear and valid signals for subsurface imaging.

[0037] like Figure 4 As shown, S2: Extract the matched and sorted towed cable data and seabed node data and perform multidimensional spatial convolution processing to obtain the multiple wave model gather. More specifically, perform multidimensional spatial convolution processing on the extracted common shot point towed cable data and common receiver point seabed node data to obtain the multiple wave model gather.

[0038] In some embodiments, the multidimensional spatial convolution processing method is as follows: in, For seabed node data of the common detection points, For common shot point tow cable data, m is the multiple wave model gather generated after convolution. and These are the x and y coordinates of the spatial location of the receiver point, respectively. and These are the x and y coordinates of the spatial location of the shot point, respectively. and , , represent the x and y coordinates of the possible downstream reflection points of the seismic waves, respectively, and t is the propagation time of the seismic wave from excitation to reception.

[0039] By combining common shot point tow cable data and common receiver point seabed node data with spatial convolution to predict multiples, all surface-related multiples can be pre-set at once, improving the prediction efficiency of multiples.

[0040] S3: Subtract the multiple wave model gather from the seabed node data to obtain the seabed node data for suppressing multiple waves.

[0041] In some embodiments, step S3 includes: subtracting the adaptive amplitude and phase-matched multiple wave model gather and the common receiver point seabed node data from the seabed node data to obtain the common receiver point seabed node data for suppressing multiple waves.

[0042] Adaptive amplitude and phase matching performs fine correction of amplitude and phase in a dynamic, time-varying manner. Unlike the least squares matched filtering process in the above embodiments, adaptive matching emphasizes independent solution for each local location, rather than using the same set of matched filtering parameters for the entire survey area. Therefore, the data obtained by adaptive energy is more accurate.

[0043] like Figure 5-A , Figure 5-B The upflow wave profile of the seabed node after multiple wave suppression clearly shows that after multiple wave suppression... Figure 5-B The background color uniformity is better, and the background is cleaner, meaning that weak reflection signals (such as deep, low-amplitude in-phase axes) that were previously masked by multiple waves begin to appear; in addition, in-phase axes at the same location are more coherent and smoother, and fault breaks are clearer, all indicating that the present invention has a better effect on suppressing multiple waves on the surface of seabed nodes, with less residual multiple waves. Figure 6 As shown, low-frequency energy is significantly enhanced, and the mid-to-high frequency bands overlap. After eliminating the differences through least-squares matching and adaptive amplitude and phase matching alignment, a more accurate multiple wave model gather is obtained. Then, the predicted multiple wave model gather is directly subtracted from the original seismic data, thus obtaining seafloor node data with a more significant suppression effect.

[0044] In some embodiments, the subtraction of multiple wave model gathers and common receiver point seabed node data from seabed node data is performed in the time-space domain or in the curve wave domain.

[0045] In this embodiment, the temporal-spatial domain is used to limit the time length and number of channels, while the curved wave domain is used to limit the direction and scale. Regardless of whether the operation is performed in the temporal-spatial domain or the curved wave domain, multiple waves are fitted from other directions to avoid interference with the effective wave direction.

[0046] The present invention also discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the multiple wave suppression method for seabed node data as described in any of the above embodiments.

[0047] It is understood that the above embodiments only illustrate some implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above embodiments or technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. That is, the embodiments described "in some embodiments" can be freely combined with any of the preceding and following embodiments. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A method for suppressing multiple waves of seabed node data, characterized in that, The method includes the following steps: S1: Acquire towed cable data and seabed node data from seabed monitoring, and match and sort the towed cable data and seabed node data; S2: Extract the matched and sorted towed cable data and seabed node data and perform multidimensional spatial convolution processing to obtain the multiple wave model gather; S3: Subtract the multiple wave model gather from the seabed node data to obtain the seabed node data for suppressing multiple waves.

2. The method for suppressing multiple waves of seabed node data according to claim 1, characterized in that, In step S1, the towed cable data and seabed node data are matched and sorted according to the following steps: S11: Correct the towed cable data using seabed node data to obtain the matched towed cable data; S12: Extract the dataset from the matched towed cable data and seabed node data using the shot point number and receiver point number as index words to obtain the sorted towed cable dataset and seabed node dataset.

3. The method for suppressing multiple waves of seabed node data according to claim 2, characterized in that, Step S11 includes: S111: Time difference correction is performed on towed cable data based on seabed node data; S112: Select towed cable overlay data and seabed node overlay data in areas with a signal-to-noise ratio higher than a preset threshold within the survey area, and compare the towed cable overlay data and seabed node overlay data using the least squares method to obtain the matching factor; S113: Perform matched filtering on the uncorrected tow cable data based on the matching factor.

4. The method for suppressing multiple waves of seabed node data according to claim 3, characterized in that, The matching factors include at least amplitude matching factors, frequency matching factors, and phase matching factors.

5. The method for suppressing multiple waves of seabed node data according to claim 2, characterized in that, Step S12 includes: The matched tow cable data is extracted into common-shot-point tow cable data using the shot point number as the first index and the receiver point number as the second index; and... The seabed node data is extracted using the detector point number as the first index and the shot point number as the second index to form the common detector point seabed node data.

6. The method for suppressing multiple waves of seabed node data according to claim 5, characterized in that, In step S12, the extracted seabed node data is the upflow wave data of the seabed node data.

7. The method for suppressing multiple waves of seabed node data according to claim 5, characterized in that, In step S2, the multidimensional spatial convolution processing method is as follows: in, For seabed node data of the common detection points, For common shot point tow cable data, m is the multiple wave model gather generated after convolution. and These are the x and y coordinates of the spatial location of the receiver point, respectively. and These are the x and y coordinates of the spatial location of the shot point, respectively. and , , represent the x and y coordinates of the possible downstream reflection points of the seismic waves, respectively, and t is the propagation time of the seismic wave from excitation to reception.

8. The method for suppressing multiple waves of seabed node data according to claim 5, characterized in that, Step S3 includes: subtracting the adaptive amplitude and phase matching multiple wave model gather and the common receiver point seabed node data from the seabed node data to obtain the common receiver point seabed node data for suppressing multiple waves.

9. The method for suppressing multiple waves of seabed node data according to claim 8, characterized in that, The subtraction of multiple wave model gathers and common detection point seabed node data from the seabed node data is performed in the time-space domain or in the curve wave domain.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the multiple wave suppression method for seabed node data as described in any one of claims 1-9.

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