Combined suppression method and device for multiple waves in shallow water work area and electronic equipment

Abstract

The invention relates to the technical field of oil and gas geophysics, and discloses a combined suppression method and device for multiple waves in a shallow water work area and electronic equipment. The method comprises the following steps: processing shallow water work area seismic data, and obtaining work area water bottom data; suppressing multiples by adopting a DWD method to obtain an accurate seabed of the whole work area, and then improving and obtaining a DWD multiple prediction model by utilizing a wave field continuation mode; suppressing multiple waves by adopting a GSM (Global System for Mobile Phone) method; the DWD multiple wave prediction model and the multiple wave model predicted by the GSMP are subjected to adaptive subtraction at the same time; and performing simultaneous parallel matching and adaptive subtraction by using the DWD multiple prediction model and the multiple model predicted by the GSMP to obtain data after surface related multiple suppression. According to the technical scheme, the combined method model parallel matching pressing effect is better than the single method pressing or combined method pressing model series pressing effect; effective suppression of short-period multiples of a shallow water layer is achieved, and the suppression effect is good.

Description

Technical Field

[0001] This invention relates to the field of oil and gas geophysics, specifically to a combined suppression method, apparatus, and electronic equipment for multiple waves in shallow water work areas. Background Technology

[0002] Suppressing multiples effectively is one of the challenges in marine seismic data processing. The presence of multiples in marine seismic data reduces the signal-to-noise ratio and resolution, severely impacting the final processing results and imaging quality. Primary waves are less noticeable under the influence of multiples, which are generated by reflections from seismic profiles and mid-layers. This effect prevents effective attenuation of multiples during processing, significantly impacting the accuracy of stratigraphic interpretation.

[0003] Currently, commercial software commonly employs the SRME (Surface Correlated Multiple Suppression Based on Feedback Iteration Theory) method to suppress free surface multiples. This method uses data-driven self-convolution to predict the multiple model, followed by adaptive subtraction for suppression. However, in deep water environments, multiples are relatively easy to distinguish from primary waves, and multiples can be effectively suppressed. But in shallow water environments (less than 200m), multiple suppression often fails. The main reason is that effective bottom reflections in shallow water are concentrated at the near offset, which is largely missing. Therefore, it is difficult to reconstruct the water-related multiple model using traditional self-convolution methods. Furthermore, in horizontal formations, primary and multiple waves are heavily intertwined, making accurate identification impossible.

[0004] In shallow water seismic data, only a partial SRME approach can typically be used. This involves suppressing long-period multiples generated by strong reflecting layers in the middle and deep water, rather than water-layer multiples, without utilizing seismic data near the seafloor for multiple prediction. Existing conventional methods struggle to effectively suppress these water-layer multiples, which can reduce the resolution of seismic profile records and deteriorate wave group characteristics, severely impacting accurate structural imaging.

[0005] In summary, there is an urgent need for a treatment technology to suppress short-period multiple waves in shallow water layers. Summary of the Invention

[0006] This invention provides a combined suppression method, apparatus, and electronic device for multiple waves in shallow water work areas, in order to solve the aforementioned technical problems of poor or even ineffective suppression of multiple waves in existing technologies.

[0007] According to a first aspect of the present invention, a combined suppression method for multiple waves in shallow water work areas is provided, comprising:

[0008] Process seismic data in shallow water work areas and obtain underwater data for the work areas;

[0009] The DWD method was used to suppress multiples. After processing and obtaining the accurate seabed for the entire work area, the DWD multiple prediction model was improved by wavefield extension. DWD is a deterministic water layer multiple suppression method.

[0010] The GSMP method is used to suppress multiples. In the self-convolution stage, the DWD-suppressed data is convolved with the original data. GSMP is a generalized surface multiple suppression method.

[0011] The DWD multiple prediction model and the GSMP predicted multiple model are simultaneously adaptively subtracted to improve the multiple suppression effect.

[0012] By simultaneously matching and adaptively subtracting the DWD multiple prediction model and the GSMP predicted multiple model, the surface-correlated multiple suppression data is obtained.

[0013] Preferably, in the process of processing seismic data in shallow water work areas,

[0014] Near-offset gathers of seismic data from the shallow water work area were extracted and stacked using constant velocity; autocorrelation was performed on the stacked data volume to track the first negatively correlated layer.

[0015] Preferably, after processing and obtaining the accurate seabed for the entire work area, the DWD multiple wave prediction model is improved and obtained using wavefield extension.

[0016] A forward modeling of the first-order bottom reflection is introduced, and a wave field extrapolation operator is used to simulate the first-order bottom multiples throughout the entire process. Then, the simulated model is added to the initial DWD model corresponding to the suppression of multiples using the DWD method after energy matching, to obtain a DWD multiples prediction model containing first-order bottom multiple reflections.

[0017] Preferably, the DWD method includes:

[0018] Using the two-way seabed travel time t(0) at zero gun-receiver distance, and then transforming it to the τ-p domain, the corresponding seabed period in the τ-p domain is calculated.

[0019] The original record is corrected down by one seabed reflection time period, then multiplied by the seabed reflection coefficient, and then subjected to adaptive subtraction followed by τ-p inverse transformation to obtain the predicted water layer multiple wave model.

[0020] Preferably, the combined suppression method for multiple waves in shallow water work areas further includes:

[0021] In the GSMP non-aqueous surface multiple prediction stage, the data of a large number of high-energy water layer multiples suppressed by the DWD method are used as the input of the primary wave.

[0022] According to a second aspect of the present invention, a combined suppression device for multiple waves in shallow water work areas is provided, comprising:

[0023] The seismic data processing module is used to process seismic data in shallow water work areas and acquire underwater data of the work areas;

[0024] The DWD processing module is used to suppress multiples using the DWD method. After processing and obtaining the accurate seabed for the entire work area, the DWD multiple prediction model is improved by wavefield extension. Here, DWD is deterministic water layer multiple suppression.

[0025] The GSMP self-convolution module is used to suppress multiples using the GSMP method. In the self-convolution step, the DWD-suppressed data is convolved with the original data. GSMP is a generalized surface multiple suppression.

[0026] The first processing module is used to simultaneously perform adaptive subtraction between the DWD multiple prediction model and the GSMP-predicted multiple model to improve the multiple suppression effect; and

[0027] The second processing module is used to simultaneously perform parallel matching and adaptive subtraction between the DWD multiple prediction model and the GSMP predicted multiple model to obtain the surface-correlated multiple suppressed data.

[0028] Preferably, the DWD processing module includes:

[0029] DWD suppression module, used to suppress multiple waves using the DWD method; and

[0030] The DWD improvement module is used to process and obtain the accurate seabed of the entire work area, and then improve and obtain the DWD multiple wave prediction model by wavefield extension.

[0031] Preferably, the DWD compression module includes:

[0032] The first calculation module is used to calculate the corresponding seabed period in the τ-p domain by utilizing the two-way seabed travel time t(0) at the zero-shot-receiver distance and transforming it to the τ-p domain; and

[0033] The second calculation module is used to correct the original record down by one seabed reflection time period, multiply it by the seabed reflection coefficient, and then perform an adaptive subtraction followed by an inverse τ-p transformation.

[0034] According to a third aspect of the present invention, an electronic device is provided, comprising:

[0035] Memory; and

[0036] processor;

[0037] The memory is used to store one or more computer instructions; the one or more computer instructions are executed by the processor to implement the method described in any of the above.

[0038] According to a fourth aspect of the present invention, a readable storage medium is provided, wherein computer instructions are stored thereon; wherein, when executed by a processor, the computer instructions implement the method described in any of the preceding claims.

[0039] The technical solution of this invention, with its combined method model in parallel matching, achieves a better suppression effect than a single method or a combined method model in series; it effectively suppresses short-period multiple waves in shallow water layers, and the suppression effect is superior.

[0040] In the technical solution of this invention, by utilizing the pre-stack denoising data volume and comparing the main frequency and bandwidth, the combined suppression effect of multiple methods and the effect before and after subtracting the series and parallel model matching can be determined, which can further improve the suppression effect of multiple waves. Attached Figure Description

[0041] Figure 1 This is a schematic flowchart of a combined suppression method for multiple waves in shallow water work areas, as described in one embodiment.

[0042] Figure 2 This is a flowchart illustrating the parallel matching subtraction (step S6) step in a combined suppression method for multiple waves in shallow water work areas, as described in one embodiment.

[0043] Figure 3 This is a schematic diagram of the structure of a combined suppression device for multiple waves in shallow water work areas in one embodiment;

[0044] Figure 4 This is a schematic diagram of a near-offset superposition profile after autocorrelation of superimposed data volumes in one embodiment;

[0045] Figure 5 This is a schematic diagram illustrating the negative correlation tracking and picking of underwater time and depth in one embodiment.

[0046] Figure 6 This is a comparison diagram of single-shot records before and after deterministic water layer multiple wave suppression in one embodiment;

[0047] Figure 7 This is a comparison diagram of superimposed records before and after deterministic water layer multiple wave suppression in one embodiment;

[0048] Figure 8 This is a comparison chart of autocorrelation records before and after deterministic water layer multiple wave suppression in one embodiment;

[0049] Figure 9 This is a comparison image of single-shot records before and after multiple wave suppression on a free surface in one embodiment.

[0050] Figure 10 This is a comparison image of the superimposed records before and after multiple wave suppression on a free surface in one embodiment;

[0051] Figure 11 This is a comparison image of superimposed records after deterministic multiple wave suppression of a water layer and after multiple wave suppression of a free surface in one embodiment;

[0052] Figure 12 This is a comparison diagram of autocorrelation records before and after multiple wave suppression on a free surface in one embodiment.

[0053] Figure 13 This is a comparison chart of autocorrelation records superimposed on an embodiment before and after series and parallel suppression;

[0054] Figure 14 This is a comparison chart of the spectrum records before and after series and parallel suppression in one embodiment. Detailed Implementation

[0055] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0056] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0057] It should be noted that the terms "first," "second," etc., used in this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0058] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Moreover, in this invention, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0059] Example 1

[0060] Suppression of surface multiples in shallow water has always been a challenge in the industry. Deterministic water layer multiple suppression (DWD) or free surface multiple suppression (GSMP) are among the more effective methods used in industry in recent years. When this method is applied to surface multiple suppression in shallow water, two problems are found: (1) Due to the superposition of primary bottom reflection and refracted waves, it is difficult to effectively predict first-order high-energy bottom reflection multiples when the DWD extrapolation operator is applied to the data; (2) Residual multiples still exist in the trace concentration after suppression by the GSMP method.

[0061] Please refer to Figure 1 , 2 This embodiment provides a combined suppression method for multiple waves in shallow water work areas, including the following steps:

[0062] S1. Process seismic data of shallow water work area to obtain seabed data of work area; wherein, extract near-offset gathers of seismic data of shallow water work area / shallow sea work area and stack them using constant velocity (water velocity); perform autocorrelation operation on stacked data volume and track the first negative correlation layer to obtain seabed data of work area.

[0063] S2. The DWD method is used to suppress multiples. After processing and obtaining the accurate seabed of the entire work area, the DWD multiple prediction model is improved by wavefield extension. Among them, DWD is a deterministic water layer multiple suppression.

[0064] S3. The GSMP method is used to suppress multiple waves. In the self-convolution step, the data after DWD suppression is convolved with the original data. The original data refers to the data before DWD suppression. GSMP is generalized surface multiple suppression. The GSMP self-convolution step in step S3 is used to improve the amplitude prediction accuracy.

[0065] S4. The DWD multiple prediction model and the GSMP predicted multiple model are simultaneously subjected to adaptive subtraction to improve the multiple suppression effect.

[0066] S5. Simultaneously perform parallel matching and adaptive subtraction between the DWD multiple prediction model and the GSMP predicted multiple model to obtain the surface-correlated multiple suppressed data. The adaptive subtraction between the DWD multiple prediction model and the GSMP predicted multiple model is performed to ensure thorough multiple suppression without damaging the effective signal.

[0067] In one embodiment of step S2, a forward-modeled first-order seabed reflection is introduced into the DWD stage, and a first-order full-range seabed multiple is simulated using a wavefield extrapolation operator. Then, the simulated model is energy-matched with the initial DWD model and added to obtain a DWD multiple prediction model containing first-order seabed multiple reflections. The initial DWD model refers to the model corresponding to the suppression of multiples using the DWD method before the simulation / before the wavefield extension improvement. Since water layer multiples exhibit seabed reflection periodicity, the DWD method includes the following sub-steps:

[0068] S211. Using the two-way seabed travel time t(0) at zero gun-receiver distance, and then transforming it to the τ-p domain, calculate the corresponding seabed period in the τ-p domain;

[0069] S212. Correct the original record downward by one seabed reflection time period, multiply by the seabed reflection coefficient, and perform an adaptive subtraction followed by τ-p inverse transformation to obtain the predicted water layer multiple wave model.

[0070] In one embodiment, the combined suppression method for multiple waves in shallow water work areas further includes step 6 in conjunction with step 3, to improve amplitude prediction accuracy:

[0071] S6. In the GSMP non-aquifer surface multiple prediction stage, the data of a large number of high-energy aquifer multiples suppressed by the DWD method are used as the input of the primary wave. In this way, the amplitude of the multiples is closer to the theoretical accuracy. Of course, its accuracy depends on the effect of deterministic aquifer multiple suppression (i.e., DWD suppression).

[0072] In summary, the combined suppression method for multiples in shallow water work areas of this invention is based on the deterministic water layer multiple (DWD) suppression derived from the wavefield extension method in the frequency-spatial domain. It uses autocorrelation to pick up the accurate seabed two-way travel time and then transforms it to the τ-p domain to calculate the corresponding seabed period in the τ-p domain. The original record is then corrected down by one seabed reflection time period, multiplied by the seabed reflection coefficient, and after adaptive subtraction and inverse τ-p transformation, the predicted water layer multiple model can be obtained.

[0073] Simultaneously, the Generalized Free Surface Multiple Suppression (GSMP) method is introduced to suppress water layer multiples. Among them, the Generalized Free Surface Multiple Prediction (GSMP) technique is a free surface multiple prediction technique applicable to rugged seabeds. Compared with the traditional free surface multiple suppression technique (SRME), GSMP simulates based on the actual location of the reflection point, resulting in a more accurate predicted multiple model.

[0074] Finally, a combination of deterministic water layer multiple suppression (DWD) and generalized surface multiple suppression (GSMP) methods is used to suppress multiples, with the prediction model relying on an accurate seabed. The tandem and parallel multiple suppression effects are investigated separately. After near-offset interpolation of the data prior to DWD, surface-related multiple prediction is performed. Then, simultaneous adaptive matching is performed between the water layer multiple model and the data prior to DWD, allowing for optimal prediction of all surface-related multiples, including all water layer-related multiples.

[0075] One innovation of this invention's combined suppression method for multiples in shallow water work areas lies in the following: First, autocorrelation picking is performed on the seabed during two-way travel using data. After obtaining an accurate seabed reading for the entire work area, wavefield extension is used to improve the prediction model. To further improve amplitude prediction accuracy, during the GSMP non-aqueous surface multiple prediction stage, data from a large number of high-energy water layer multiples suppressed after DWD are used as input for the primary wave. This ensures that the amplitude of the multiples is closer to the theoretical accuracy. Finally, the DWD multiple prediction model and the GSMP predicted multiple model are simultaneously matched and adaptively subtracted to obtain the suppressed surface-correlated multiple data. The two models are then adaptively matched before a final suppression is performed.

[0076] By comparing single-shot records, superimposed profiles, and dominant frequency attributes before and after different combinations of tandem and parallel suppression methods (see Example 5), the effectiveness of this method can be analyzed from multiple perspectives, effectively improving the suppression effect of multiple waves in shallow water work areas.

[0077] Example 2

[0078] Please refer to Figure 3 One embodiment provides a combined suppression device for multiple waves in shallow water work areas, comprising the following structure:

[0079] 1. Seismic Data Processing Module

[0080] The seismic data processing module 10 is used to process seismic data in shallow water work areas and acquire underwater data of the work areas.

[0081] 2. DWD Processing Module

[0082] The DWD processing module 20 is used to suppress multiples using the DWD method. After processing and obtaining the accurate seabed for the entire work area, it improves and obtains the DWD multiple prediction model by using wavefield extension. Here, DWD is deterministic water layer multiple suppression.

[0083] 3. GSMP Self-Convolution Module

[0084] The GSMP self-convolution module 30 is used to suppress multiple waves using the GSMP method. In the self-convolution stage, the data after DWD suppression is convolved with the original data. GSMP is a generalized surface multiple suppression.

[0085] 4. First processing module

[0086] The first processing module 40 is used to simultaneously perform adaptive subtraction between the DWD multiple prediction model and the GSMP predicted multiple model to improve the multiple suppression effect.

[0087] 5. Second processing module

[0088] The second processing module 50 is used to simultaneously perform parallel matching and adaptive subtraction between the DWD multiple prediction model and the GSMP predicted multiple model to obtain the surface-correlated multiple suppressed data.

[0089] 6. Third processing module

[0090] The third processing module 60 is used in the GSMP non-aqueous surface multiple prediction stage to take the data of a large number of high-energy water layer multiples suppressed by the DWD method as the input of the primary wave. The third processing module 60 works in conjunction with the GSMP self-convolution module 30.

[0091] In one embodiment, the DWD processing module 20 includes a DWD suppression module 210 and a DWD improvement module 220. The DWD suppression module 210 is used to suppress multiples using the DWD method; the DWD improvement module 220 is used to process and obtain a precise seabed prediction model for the entire work area, and then improve it using wavefield extension to obtain a DWD multiple prediction model.

[0092] In one embodiment, the DWD suppression module 210 includes: a first calculation module 2101 and a second calculation module 2102. The first calculation module 2101 is used to calculate the corresponding seabed period in the τ-p domain by using the two-way seabed travel time t(0) at zero gun-receiver distance and then transforming it to the τ-p domain; the second calculation module 2102 is used to correct the original record down by one seabed reflection time period, multiply it by the seabed reflection coefficient, and then perform an adaptive subtraction and τ-p inverse transformation.

[0093] It should be noted that the above-mentioned combined suppression device for multiple waves in shallow water work areas is used to implement the combined suppression method for multiple waves in shallow water work areas in the above embodiments, and each module in the device corresponds to each step in the method.

[0094] The following is a combined suppression method for multiples in shallow water seismic areas, which improves the noise suppression process: First, a forward-modeled first-order seabed reflection is introduced into the DWD stage, and a wavefield extrapolation operator is used to simulate first-order full-range seabed multiples. Then, this model is added to the initial DWD model after energy matching to obtain a DWD multiple prediction model containing first-order seabed multiple reflections. After adaptive matching and subtraction with the original data, the improved DWD-processed data is convolved with the original data in the GSMP self-convolution stage to improve amplitude prediction accuracy. Finally, the DWD multiple prediction model and the multiple prediction model from GSMP are simultaneously adaptively subtracted to further improve the multiple suppression effect. The improved process is applied to seismic data processing in shallow water seismic areas. The results show that first-order seabed multiples in the stacked profile are significantly suppressed, and the coherent and constructive phenomena of multiples in the shot domain and common offset domain gathers are also significantly alleviated (see Example 5).

[0095] Example 3

[0096] Based on the same inventive concept, one embodiment of the present invention provides an electronic device, including: a memory and a processor; wherein the memory is used to store one or more computer instructions; the one or more computer instructions are executed by the processor using any of the methods described in the above embodiments.

[0097] Example 4

[0098] Based on the same inventive concept, one embodiment of the present invention provides a readable storage medium storing computer instructions; wherein, when the computer instructions are executed by a processor, they implement the method of any one of the above embodiments.

[0099] One or more of the aforementioned computer instructions can form a program.

[0100] The aforementioned program can run on a processor or be stored in memory (or computer-readable medium). Computer-readable medium includes both permanent and non-permanent, removable and non-removable media, and information storage can be achieved by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable medium does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0101] These computer programs may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes can be implemented using different modules, and different steps can be implemented using different modules.

[0102] Example 5

[0103] This invention applies the combined suppression method, apparatus, electronic device, and readable storage medium for multiples in shallow water exploration areas, using actual seismic exploration data from a shallow water offshore exploration area overseas as an example to demonstrate the application process and effects of the invention. Please refer to [link / reference]. Figure 4-14 .

[0104] (1) Near-offset gathers were extracted from seismic data of the shallow sea area, and stacked using constant velocity (water velocity). The stacked data volume was then autocorrelated, and the autocorrelated near-offset stacked profile is shown below. Figure 4 We tracked its first negatively correlated layer to obtain its underwater data.

[0105] After being retrieved, the underwater time and depth of the work area are as follows: Figure 5 As shown in the diagram.

[0106] (2) First, the deterministic water layer multiple suppression method is used to suppress short-period multiples related to the seabed. The key parameters of DWD technology are the acquisition of the seabed period time and the definition of water velocity and seabed reflection coefficient. In particular, the seabed period is the time acquired after dynamic correction of water velocity. Figure 6 The comparison of single-shot recordings before and after multiple wave suppression shows that the strong first-order multiple waves below the seabed reflection are attenuated, the "multi-axis" phenomenon following the effective reflection is partially eliminated, and the energy of the effective in-phase axis is basically not lost.

[0107] Figure 7 For the comparison of superimposed profiles before and after DWD suppression, the effective reflection is highlighted after removing the seafloor multiples, especially the reflection characteristics of the mid-deep layers. After removing the multiples, the wave impedance characteristics in the profile are more obvious. Figure 8 The autocorrelation of the superimposed profiles before and after DWD suppression is compared from 0.8s to 2s. It can be seen that the first-order multiples are significantly suppressed, but some multiples still exist.

[0108] (3) The GSMP method is mainly a free surface multiple suppression technique developed for rugged seabeds. Compared with the traditional SRME technique, its advantage lies in its better suppression effect on multiples occurring at inclined interfaces. Due to the complex structure of the East China Sea shelf, especially in the depression areas, the strata are highly undulating, increasing the difficulty of multiple removal. Since the seabed-related short-period multiples have already been attenuated, seabed removal preprocessing is required in the GSMP process. The purpose is to predict only the long-period multiples related to the strata, without predicting the seabed-related multiples. The main key parameters are the aperture and grid of the target channel, as well as the selection of the nearest neighbor search algorithm.

[0109] Figure 9 A comparison of single-shot records before and after removing multiples in GSMP shows that long-period multiples are attenuated well, with the effective signal largely undamaged, and the signal-to-noise ratio of the shot gather is improved. However, multiples still remain at mid- to long-range offsets. Analysis of the suppression effect from the stacked profile ( Figure 10 Because the first-order multiples of the basement have strong energy and are very clear in imaging, after being removed by GSMP technology, the basement multiples on the superimposed profile are suppressed to a certain extent, and the morphology of the middle and deep structures is clearer.

[0110] Analysis of the effects of superimposed profile compression using different methods ( Figure 11 After removal using DWD technology, the shallow multiaxial phenomenon caused by multiple wave suppression in the water layer is improved. After removal using GSMP technology, the morphology of the middle and deep layers becomes clearer.

[0111] Figure 12 The autocorrelation of the superimposed profiles before and after GSMP suppression is compared from 0.8s to 2s. It can be seen that the energy of the multiples is reduced throughout the entire process, but some multiples still exist.

[0112] (4) The suppression effect of multiple waves was compared and analyzed from the superposition profile and spectrum by using the conventional series subtraction method and the newly improved DWD+GSMP parallel combination method respectively.

[0113] Figure 13 The comparison of superimposed records before and after suppression using series and parallel model matching for shallow water surface multiples shows that the improved parallel model matching method significantly improves the suppression of the short axis of multiples in near-offset water layers. The autocorrelation records also indicate that while the conventional series combination method can suppress most of the surface multiple energy, some residual energy remains. With the improved method, this constructive interference phenomenon is largely eliminated, and first-order bottom-reflected multiples are also significantly suppressed.

[0114] From the corresponding spectrum, the conventional cascade combination method recovers the notch frequencies of shallow water multiples to some extent. However, the improved method has a greater advantage over the conventional method at some notch frequencies. Figure 14 As shown in the figure, the change is more gradual in this notch frequency region, and the "pit-like" shape of the notch frequency is better restored.

[0115] When this invention was applied to seismic data processing in shallow water areas, the results showed that first-order seafloor multiples in the stacked profile were significantly suppressed, and the coherent and constructive phenomena of multiples in the shot domain and common offset domain gathers were also significantly alleviated.

[0116] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined suppression method for multiple waves in shallow water work areas, characterized in that, include: Process seismic data in shallow water work areas and obtain underwater data for the work areas; The DWD method was used to suppress multiples. After processing and obtaining the accurate seabed for the entire work area, the DWD multiple prediction model was improved by wavefield extension. DWD is a deterministic water layer multiple suppression method. The GSMP method is used to suppress multiples. In the self-convolution stage, the DWD-suppressed data is convolved with the original data. GSMP is a generalized surface multiple suppression method. The DWD multiple prediction model and the GSMP predicted multiple model are simultaneously adaptively subtracted to improve the multiple suppression effect. By simultaneously matching and adaptively subtracting the DWD multiple prediction model and the GSMP predicted multiple model, the surface-correlated multiple suppression data is obtained.

2. The combined suppression method for multiple waves in shallow water work areas according to claim 1, characterized in that, In the processing of seismic data in shallow water work areas Near-offset gathers of seismic data from the shallow water work area were extracted and stacked using constant velocity; autocorrelation was performed on the stacked data volume to track the first negatively correlated layer.

3. The combined suppression method for multiple waves in shallow water work areas according to claim 1, characterized in that, After processing and obtaining the accurate seabed for the entire work area, the DWD multiple wave prediction model is improved using wavefield extension. A forward modeling of the first-order bottom reflection is introduced, and a wave field extrapolation operator is used to simulate the first-order bottom multiples throughout the entire process. Then, the simulated model is added to the initial DWD model corresponding to the suppression of multiples using the DWD method after energy matching, to obtain a DWD multiples prediction model containing first-order bottom multiple reflections.

4. The combined suppression method for multiple waves in shallow water work areas according to claim 1, characterized in that, The DWD method includes: Using the two-way seabed travel time t(0) at zero gun-receiver distance, and then transforming it to the τ-p domain, the corresponding seabed period in the τ-p domain is calculated. The original record is corrected down by one seabed reflection time period, then multiplied by the seabed reflection coefficient, and then subjected to adaptive subtraction followed by τ-p inverse transformation to obtain the predicted water layer multiple wave model.

5. The combined suppression method for multiple waves in shallow water work areas according to any one of claims 1-4, characterized in that, The combined suppression method for multiple waves in shallow water work areas also includes: In the GSMP non-aqueous surface multiple prediction stage, the data of a large number of high-energy water layer multiples suppressed by the DWD method are used as the input of the primary wave.

6. A combined suppression device for multiple waves in shallow water work areas, characterized in that, include: The seismic data processing module is used to process seismic data in shallow water work areas and acquire underwater data of the work areas; The DWD processing module is used to suppress multiples using the DWD method. After processing and obtaining the accurate seabed for the entire work area, the DWD multiple prediction model is improved by wavefield extension. Here, DWD is deterministic water layer multiple suppression. The GSMP self-convolution module is used to suppress multiples using the GSMP method. In the self-convolution step, the DWD-suppressed data is convolved with the original data. GSMP is a generalized surface multiple suppression. The first processing module is used to simultaneously perform adaptive subtraction between the DWD multiple prediction model and the GSMP-predicted multiple model to improve the multiple suppression effect; and The second processing module is used to simultaneously perform parallel matching and adaptive subtraction between the DWD multiple prediction model and the GSMP predicted multiple model to obtain the surface-correlated multiple suppressed data.

7. The combined suppression device for multiple waves in shallow water working areas according to claim 6, characterized in that, The DWD processing module includes: DWD suppression module, used to suppress multiple waves using the DWD method; and The DWD improvement module is used to process and obtain the accurate seabed of the entire work area, and then improve and obtain the DWD multiple wave prediction model by wavefield extension.

8. The combined suppression device for multiple waves in shallow water work areas according to claim 7, characterized in that, The DWD compression module includes: The first calculation module is used to calculate the corresponding seabed period in the τ-p domain by utilizing the two-way seabed travel time t(0) at the zero-shot-receiver distance and transforming it to the τ-p domain; and The second calculation module is used to correct the original record down by one seabed reflection time period, multiply it by the seabed reflection coefficient, and then perform an adaptive subtraction followed by an inverse τ-p transformation.

9. An electronic device, characterized in that, include: Memory; and processor; The memory is used to store one or more computer instructions; the one or more computer instructions are executed by the processor to implement the method according to any one of claims 1 to 5.

10. A readable storage medium, characterized in that, The readable storage medium stores computer instructions; wherein, when executed by a processor, the computer instructions implement the method described in any one of claims 1 to 5.

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