Free surface multi-wave suppression method and apparatus for ocean bottom node data

Abstract

A free surface multi-wave suppression method for ocean bottom node data, relating to the technical field of seismic exploration. The method comprises: performing interpolation of upgoing wave and downgoing wave ocean bottom node data (S110); separating multiple waves according to periodic characteristics of a wave field incident angle change (S120); and using a sparse inversion method to establish a target function, and, on the basis of the target function and by means of a fast iterative shrinkage threshold, solving for an upgoing wave field that does not contain multiple waves related to a free surface (S130), so as to remove multiple waves on the free surface. According to the method, multiple waves on a free surface in an upgoing wave field of ocean bottom node data of an ultra-shallow water area can be removed, and primary wave imaging quality of seismic data is improved. Further provided is a free surface multi-wave suppression apparatus for ocean bottom node data, a computer device, and a computer program product.

Description

Method and device for suppressing free surface multiple waves of seabed node data Technical Field

[0001] The present invention relates to the technical field of seismic exploration, and in particular to a method and device for suppressing free surface multiple waves of seabed node data. Background Art

[0002] Compared with traditional narrow azimuth (NAZ) streamer acquisition, ocean bottom node (OBN) exploration has the advantages of flexible acquisition construction, ultra-long offset reception, omnidirectional, high coverage, repeatability, broadband, and multi-component. It plays an important role in the exploration of complex offshore oil and gas fields and the development of oil and gas reservoirs, and is gradually replacing streamer acquisition.

[0003] During ocean bottom node (OBN) acquisition, three-component geophones, both waterborne and landborne, are buried on the ocean floor to record pressure and velocity data. The waterborne P-component geophone is a non-directional pressure geophone; the landborne three-component geophone is a directional velocity geophone, consisting of X, Y, and Z components, with the Z component receiving longitudinal wave signals perpendicular to the seafloor. Wavefield separation using the waterborne P-component and landborne Z-component allows for upgoing and downgoing waves. However, the upgoing wavefield still contains a large number of multiples associated with the free surface (sea surface), including shot point ghost waves, water layer multiples, and free surface multiples associated with the reflector layer. These multiples severely impact the quality of exploration data, create structural artifacts, and increase exploration risk. Therefore, they must be removed during data processing.

[0004] Existing technologies use upgoing and downgoing wavefield deconvolution, which effectively removes free-surface multiples from the upgoing wavefield in relatively deep waters (greater than 20 meters) and flat seabeds. However, when processing OBN data collected in ultra-shallow waters (1-20 meters), the number of direct waves (downgoing waves) is very scarce and masked by strong energy noise. Furthermore, the wavefield propagation distance is comparable to the size of the gun array, and the wavefield recorded by the seabed nodes is extremely complex. The upgoing wave imaging accuracy of OBN data in ultra-shallow waters is severely affected by the multiples, making it difficult for existing upgoing and downgoing wavefield deconvolution technologies to achieve ideal results.

[0005] Summary of the Invention

[0006] In order to solve the defects of the prior art, the present invention provides a method for suppressing free surface multiple waves of seabed node data, which effectively removes free surface multiple waves in the upgoing wave field of seabed node data in ultra-shallow waters.

[0007] In one aspect, the present invention provides a method for suppressing free surface multiple waves of seabed node data, comprising:

[0008] Interpolate upgoing and downgoing seafloor node data;

[0009] Separate multiple waves according to the periodic characteristics of the wave field incident angle change;

[0010] The objective function is established using the sparse inversion method;

[0011] Based on the objective function, the upgoing wavefield without free surface related multiple waves is solved by fast iterative shrinkage threshold to remove free surface multiple waves.

[0012] In the embodiment of the present invention, the interpolation of the upgoing wave and downgoing wave seabed node data includes: performing high-density interpolation of the upgoing wave and downgoing wave seabed node data in the frequency-wavenumber domain using Fourier transform.

[0013] In an embodiment of the present invention, the wave field of sparse spatial sampling is forward transformed from the sparse spatiotemporal domain to the FKK domain; a relevant threshold value is set, and effective information of the wave field is extracted in an iterative manner to perform high-density interpolation; and the upgoing and downgoing waves are inversely transformed back to the spatiotemporal domain of high-density spatial sampling.

[0014] In the embodiment of the present invention, separating the multiple waves according to the periodic characteristics of the wavefield incident angle variation includes: performing a three-dimensional Taup transform on the P component and the Z component of the multiple waves respectively, and separating the multiple waves according to the periodic characteristics of the wavefield incident angle variation.

[0015] In the embodiment of the present invention, the formula of the three-dimensional Taup transformation is:

[0016] Where, τ = t-px;

[0017] Among them, V * represents the apparent velocity, θ represents the incident angle of the seismic wave ray, V represents the wave velocity in the medium, t is the time domain sample point, P x is the P value sampling in the x direction, P y The P value sampling in the y direction represents the incident angle of the wave field.

[0018] In the embodiment of the present invention, the objective function established by the sparse inversion method is:

[0019] Where, U=D*r; r i+1 =T τ [r i +D H (U-Dr i )];

[0020] U represents the upgoing wave field, D represents the downgoing wave field, r is the underground reflection coefficient sequence, λ is the regularization parameter, T τ is the transform domain threshold operator, i refers to the i-th iteration.

[0021] In an embodiment of the present invention, the method for suppressing multiple waves of the free surface of seabed node data further includes: inversely transforming the upgoing wavefield after the multiple waves are suppressed back to the time domain to obtain the upgoing wavefield after the time domain free surface related multiple waves are attenuated.

[0022] In the embodiment of the present invention, the upgoing wavefield after the multiple wave suppression is inversely transformed back to the time domain by a three-dimensional Taup inverse transform to obtain a time domain Vz noise model;

[0023] The formula for the three-dimensional Taup inverse transform is:

[0024] Among them, t is the time domain sample point, P x is the P value sampling in the x direction, P y The P value sampling in the y direction represents the incident angle of the wave field.

[0025] Another aspect of the present invention provides a device for suppressing multiple waves of free surface waves at a seabed node, comprising:

[0026] Interpolation module, used to interpolate upgoing and downgoing seabed node data;

[0027] The multiple wave separation module is used to separate the multiple waves according to the periodic characteristics of the wave field incident angle change;

[0028] The multiple wave suppression module is used to establish an objective function using the sparse inversion method. Based on the objective function, the upgoing wave field without free surface related multiple waves is solved by fast iterative shrinkage threshold to remove free surface multiple waves.

[0029] The present invention also provides a computer device, comprising: a memory, a processor, and a computer program, wherein the computer program is stored in the memory and configured to be executed by the processor to implement the above-mentioned seabed node data free surface multiple wave suppression method.

[0030] Based on the model that the convolution of the underground reflection coefficient sequence of the downgoing wavefield of OBN data is equivalent to the upgoing wavefield, the present invention performs high-density interpolation on the OBN data, comprehensively utilizes the upgoing and downgoing wavefield information in the high-precision three-dimensional TauP domain, establishes a related objective function through a sparse inversion method, and solves the upgoing wavefield without free-surface related multiple waves through a fast iterative shrinkage threshold method. This avoids the instability caused by signal division in traditional deconvolution algorithms, can effectively remove free-surface multiple waves in the upgoing wavefield of OBN data in ultra-shallow waters, provides a real and reliable data basis for geological research, and reduces exploration risks.

[0031] Other features and advantages of the technical solution of the present invention will be described in detail in the specific implementation section below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] FIG1 is a flow chart of a method for suppressing multiple waves from free surface of seabed node data provided by an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of multiple waves in the time-space domain (left) and multiple waves in the Taup domain (right);

[0035] Figure 3 is a schematic diagram of the gather before multiple wave attenuation (left) and after multiple wave attenuation (right);

[0036] FIG4 is a schematic diagram of a stacked cross section before multiple waves attenuate;

[0037] FIG5 is a schematic diagram of a superposition cross section after multiple waves have attenuated;

[0038] FIG6 is a comparison diagram of the actual data cross section after the multiple waves are attenuated by the traditional wave suppression method and the cross section after the multiple waves are attenuated by the present invention;

[0039] FIG7 is a comparison diagram of the application effects of the multiple wave suppression method of the present invention in actual production projects. DETAILED DESCRIPTION

[0040] To make the technical solutions and advantages of the embodiments of the present invention more clearly understood, exemplary embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It should be noted that the embodiments described are only a portion of the embodiments of the present invention, and are not an exhaustive list of all embodiments. It should be noted that the embodiments of the present invention and the features thereof may be combined with each other unless they conflict.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] As described in the background, existing technologies employ upgoing and downgoing wavefield deconvolution, which effectively removes free-surface multiples from the upgoing wavefield in relatively deep waters (greater than 20 meters) and flat seabeds. However, when processing OBN data collected in ultra-shallow waters (1-20 meters), the number of direct waves (downgoing waves) is extremely scarce and masked by strong energy noise. Furthermore, the wavefield propagation distance is comparable to the size of the gun array, and the wavefield recorded by the seafloor nodes is extremely complex. The upgoing wave imaging accuracy of OBN data in ultra-shallow waters is severely affected by the multiples, making it difficult for existing upgoing and downgoing wavefield deconvolution techniques to achieve ideal results.

[0043] An embodiment of the present invention provides a method for suppressing free surface multiple waves from seafloor node data. Based on a model in which the convolution of the subsurface reflection coefficient sequence of the downgoing wavefield of OBN data is equivalent to the upgoing wavefield, the OBN data is subjected to high-density interpolation. Then, the upgoing and downgoing wavefield information is comprehensively utilized in a high-precision three-dimensional TauP domain. A related objective function is established through a sparse inversion method. The upgoing wavefield without free surface-related multiple waves is solved through a fast iterative shrinkage threshold method. This avoids the instability caused by signal division in traditional deconvolution algorithms, effectively removes free surface multiple waves from the upgoing wavefield of OBN data in ultra-shallow waters, provides a real and reliable data basis for geological research, and reduces exploration risks.

[0044] FIG1 is a flow chart of a method for suppressing multiple waves from a free surface of a seabed node provided by an embodiment of the present invention. As shown in FIG1 , the method for suppressing multiple waves from a free surface of a seabed node provided by this embodiment includes the following steps:

[0045] S110, interpolating upgoing wave and downgoing wave seabed node data;

[0046] S120, separating the multiple waves according to the periodic characteristics of the change in the wave field incident angle;

[0047] S130, establishing an objective function using a sparse inversion method, and solving an upgoing wave field without free surface related multiple waves by rapidly iteratively shrinking a threshold based on the objective function to remove the free surface multiple waves;

[0048] S140, inversely transforming the upgoing wavefield after the multiple wave suppression back into the time domain.

[0049] In the above step S110, Fourier transform is used to perform high-density interpolation on the upgoing wave and downgoing wave seabed node data in the frequency-wavenumber domain (FK domain), and both the upgoing wave field and the downgoing wave field are interpolated into high-density spatial sampling (sampling interval is less than or equal to 6.25 meters).

[0050] Specifically, the wave field of sparse spatial sampling is forward transformed from the sparse spatiotemporal domain to the FKK domain, relevant threshold values ​​are set, and effective information of the wave field is extracted through iteration. It is then inversely transformed back to the spatiotemporal domain of high-density spatial sampling to complete the high-density interpolation process. That is, forward transformation, high-density interpolation, and inverse transformation are performed on the upgoing and downgoing waves respectively. The formula for the forward transformation is as follows:

[0051] The formula for the inverse transform is as follows:

[0052] In the forward transform, x represents a time domain sampling point or a space domain sampling point, and in the inverse transform, k represents a frequency domain sampling point or a beam domain sampling point.

[0053] In step S120, Taup transformation is used to separate multiple waves according to the periodic characteristics caused by the change of the wave field incident angle. Specifically, it includes: performing a three-dimensional Taup transformation on the P component and Z component of the multiple waves respectively. Taking the two-dimensional Taup transformation as an example, the formula is:

[0054] In formula (3), τ = t-px; (4)

[0055] Among them, V * represents the apparent velocity, θ represents the incident angle of the seismic wave ray, and V represents the wave velocity in the medium;

[0056] Expanded to three-dimensional Taup transform, its formula is:

[0057] In formula (6), τ = t - px;

[0058] Among them, V * represents the apparent velocity, θ represents the incident angle of the seismic wave ray, V represents the wave velocity in the medium, t is the time domain sample point, P x is the P value sampling in the x direction, P y The P value sampling in the y direction represents the incident angle of the wave field.

[0059] In the above step S130, a sparse inversion method is used in the three-dimensional Taup domain to establish a relevant objective function, and the upgoing wave field without free surface related multiple waves is solved by fast iterative shrinkage threshold, which effectively avoids the instability caused by signal division in the traditional upgoing and downgoing wave field deconvolution algorithm. The objective function established by the sparse inversion method is: U = D*r; (7) r i+1 =T τ [r i +D H (U-Dr i )]; (9)

[0060] Equation (7) is derived based on the model that the convolution of the downgoing wavefield of OBN data into the subsurface reflection coefficient sequence is equivalent to the upgoing wavefield, where U represents the upgoing wavefield, D represents the downgoing wavefield, and r is the subsurface reflection coefficient sequence. From Equation (7), we can deduce:

[0061] Formula (8) is the objective function, λ is the regularization parameter;

[0062] In formula (9), T τ is the transform domain threshold operator, i refers to the i-th iteration.

[0063] In step S140, the upgoing wavefield after multiple wave suppression is inversely transformed back to the time domain through a three-dimensional Taup inverse transform to obtain a time domain Vz noise model, thereby obtaining the upgoing wavefield after the free surface-related multiple waves are attenuated in the time domain. The formula for the three-dimensional Taup inverse transform is:

[0064] In formula (10), t is the time domain sample point, P x is the P value sampling in the x direction, P y The P value sampling in the y direction represents the incident angle of the wave field.

[0065] In a specific application scenario, the Taup transform is used to separate multiple waves according to the wavefield incident angle, as shown in Figure 2. The left portion shows the multiple waves in the time-space domain, and the right portion shows the multiple waves in the Taup domain. The test results based on theoretical data are shown in Figure 3. The left portion shows the gather before the multiple waves are attenuated, and the right portion shows the gather after the multiple waves are attenuated. The stacked cross-section before the multiple waves are attenuated is shown in Figure 4, and the stacked cross-section after the multiple waves are attenuated is shown in Figure 5. Comparing Figures 4 and 5 shows that the imaging effect is better after the multiple waves are attenuated. Based on actual data, a comparison of the test results using a traditional multiple wave suppression method and the multiple wave suppression method of the present invention is shown in Figure 6. The left portion of the figure shows the cross-section after the multiple waves are attenuated using the traditional wave suppression method, and the right portion shows the cross-section after the multiple waves are attenuated using the present invention. In an actual production project, the application effect of the multiple wave suppression method of the present invention is compared, as shown in Figure 7. The upper portion of the figure shows the cross-section before the multiple waves are attenuated, and the lower portion shows the cross-section after the multiple waves are attenuated. Figure 7 shows that the imaging effect is better after the multiple waves are attenuated.

[0066] After multiple wave suppression is performed using the method provided in the above embodiment, all relevant multiple wave noise caused by the strongly reflecting sea surface is effectively attenuated, which significantly improves the primary wave imaging quality of the seismic data, obtains processing results that can accurately reflect the underground geological conditions, provides a high-fidelity data basis for interpreting well locations, effectively improves the drilling success rate, and reduces exploration risks.

[0067] Embodiments of the present invention also provide a device for suppressing free-surface multiples from seafloor node data, comprising an interpolation module, a multiple separation module, and a multiple suppression module. The interpolation module is configured to interpolate upgoing and downgoing seafloor node data. The multiple separation module is configured to separate multiples based on the periodic characteristics of the wavefield's incident angle. The multiple suppression module is configured to establish a target function using a sparse inversion method. Based on the target function, the device solves for an upgoing wavefield that does not contain free-surface-related multiples by rapidly iteratively shrinking a threshold, thereby removing free-surface multiples.

[0068] In one embodiment, the interpolation module uses Fourier transform to perform high-density interpolation on the upgoing and downgoing seabed node data in the frequency-wavenumber domain (FK domain), and interpolates both the upgoing and downgoing wave fields into high-density spatial sampling (sampling interval is less than or equal to 6.25 meters).

[0069] Specifically, the wave field of sparse spatial sampling is forward transformed from the sparse spatiotemporal domain to the FKK domain, relevant threshold values ​​are set, and effective information of the wave field is extracted through iteration. It is then inversely transformed back to the spatiotemporal domain of high-density spatial sampling to complete the high-density interpolation process. That is, forward transformation, high-density interpolation, and inverse transformation are performed on the upgoing and downgoing waves respectively. The formula for the forward transformation is as follows:

[0070] The formula for the inverse transform is as follows:

[0071] In the forward transform, x represents a time domain sampling point or a space domain sampling point, and in the inverse transform, k represents a frequency domain sampling point or a beam domain sampling point.

[0072] In one embodiment, the multiple wave separation module uses Taup transform to separate multiple waves according to the periodic characteristics caused by the change of the wave field incident angle. Specifically, it includes: performing a three-dimensional Taup transform on the P component and Z component of the multiple wave, and the formula is:

[0073] In formula (6), τ = t - px;

[0074] Among them, V * represents the apparent velocity, θ represents the incident angle of the seismic wave ray, V represents the wave velocity in the medium, t is the time domain sample point, P x is the P value sampling in the x direction, P y The P value sampling in the y direction represents the incident angle of the wave field.

[0075] In one embodiment, the multiple wave suppression module uses a sparse inversion method in the three-dimensional Taup domain to establish a related objective function, and solves the upgoing wave field without free surface related multiple waves by rapidly iteratively shrinking the threshold, effectively avoiding the instability caused by signal division in the traditional upgoing and downgoing wave field deconvolution algorithm. The objective function established by the sparse inversion method is: U = D*r; (7) r i+1 =T τ [r i +D H (U-Dr i )]; (9)

[0076] Equation (7) is derived based on the model that the convolution of the downgoing wavefield of OBN data into the subsurface reflection coefficient sequence is equivalent to the upgoing wavefield, where U represents the upgoing wavefield, D represents the downgoing wavefield, and r is the subsurface reflection coefficient sequence. From Equation (7), we can deduce:

[0077] Formula (8) is the objective function, λ is the regularization parameter;

[0078] In formula (9), T τ is the transform domain threshold operator, i refers to the i-th iteration.

[0079] The upgoing wavefield after multiple wave suppression is inversely transformed back to the time domain through the three-dimensional Taup inverse transform to obtain the time domain Vz noise model, thereby obtaining the upgoing wavefield after the free surface-related multiple waves are attenuated in the time domain. The formula for the three-dimensional Taup inverse transform is:

[0080] In formula (10), t is the time domain sample point, P x is the P value sampling in the x direction, P y The P value sampling in the y direction represents the incident angle of the wave field.

[0081] An embodiment of the present invention further provides a computer device, comprising: a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the computer program to implement the above-mentioned method for suppressing free surface multiple waves of seabed node data.

[0082] An embodiment of the present invention further provides a computer program product, comprising a computer program, which implements the above-mentioned method for suppressing seabed node data-free surface multiple waves when executed by a processor.

[0083] An embodiment of the present invention further provides a machine-readable storage medium having computer program instructions stored thereon, which implement the above-mentioned method for suppressing seabed node data free surface multiple waves when executed by a processor.

[0084] It will be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention may be implemented in various computer languages, for example, the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0085] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0086] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device that implements the functions specified in one or more processes of the flowchart and / or one or more blocks of the block diagram. These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes of the flowchart and / or one or more blocks of the block diagram.

[0087] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. A method for suppressing free surface multiples of submarine node data, characterized in that, Including: Interpolating the up-going wave and down-going wave seafloor node data; Separating the multiple waves according to the periodic characteristics of the wavefield incident angle variation; Establishing an objective function using the sparse inversion method; Based on the objective function, solving the up-going wavefield without free-surface-related multiple waves through fast iterative shrinkage thresholding to remove the free-surface multiple waves.

2. The method for suppressing the free surface multiple waves of the subsea node data according to claim 1, characterized in that The interpolating the up-going wave and down-going wave seafloor node data includes: Performing high-density interpolation on the up-going wave and down-going wave seafloor node data in the frequency-wavenumber domain using Fourier transform.

3. The method for suppressing the free surface multiple waves of the subsea node data according to claim 2, characterized in that The performing high-density interpolation on the up-going wave and down-going wave seafloor node data in the frequency-wavenumber domain using Fourier transform includes: Forward-transforming the sparsely sampled wavefield from the sparse spatio-temporal domain to the FKK domain; Setting relevant threshold values and extracting the effective information of the wavefield through an iterative method for high-density interpolation; Inverse-transforming the up-going wave and down-going wave back to the high-density spatially sampled spatio-temporal domain.

4. The method for suppressing free surface multiple waves of submarine node data according to claim 1, wherein, The separating the multiple waves according to the periodic characteristics of the wavefield incident angle variation includes: Performing three-dimensional Taup transformation on the P-component and Z-component of the multiple waves respectively to separate the multiple waves according to the periodic characteristics of the wavefield incident angle variation.

5. The method for suppressing free surface multiples of submarine node data according to claim 4, characterized in that, The formula for the three-dimensional Taup transform is as follows: In the formula, τ = t - px; Among them, V * represents the apparent velocity, θ represents the incident angle of the seismic wave ray, V represents the wave velocity in the medium, t is the time-domain sample point, and P x is the P-value sampling in the x direction, and P y is the P-value sampling in the y direction. The P value represents the incident angle of the wave field.

6. The method for suppressing the free surface multiple waves of the subsea node data according to claim 1, characterized in that, The objective function established by using the sparse inversion method is as follows: Wherein, U = D * r; r i+1 = T τ [r i + D H (U - Dr i )]; U represents the up-going wavefield, D represents the down-going wavefield, r is the sequence of subsurface reflection coefficients, λ is the regularization parameter, and T τ is the transform-domain threshold operator, and i refers to the i-th iteration.

7. The method for suppressing the free surface multiple waves of the subsea node data according to claim 1, wherein The method further includes: Inverse-transforming the up-going wavefield after multiple wave suppression back to the time domain to obtain the up-going wavefield with free-surface-related multiple waves attenuated in the time domain.

8. The method for suppressing the free surface multiple waves of the subsea node data according to claim 7, characterized in that The inverse-transforming the up-going wavefield after multiple wave suppression back to the time domain includes: Inverse-transforming the up-going wavefield after multiple wave suppression back to the time domain through three-dimensional Taup inverse transformation to obtain the Vz noise model in the time domain; The formula for the three-dimensional Taup inverse transformation is as follows: where t is the sample point in the time domain, and P x is the P-value sampling in the x direction, and P y is the P-value sampling in the y direction. The P value represents the incident angle of the wave field.

9. An apparatus for suppressing free surface multiples of seafloor node data, characterized in that Including: An interpolation module for interpolating the up-going wave and down-going wave seafloor node data; A multiple wave separation module for separating the multiple waves according to the periodic characteristics of the wavefield incident angle variation; A multiple wave suppression module for establishing an objective function using the sparse inversion method and solving the up-going wavefield without free-surface-related multiple waves based on the objective function through fast iterative shrinkage thresholding to remove the free-surface multiple waves.

10. The device for suppressing the free surface multiple waves of the subsea node data according to claim 9, wherein The interpolation module performs high-density interpolation on the up-going wave and down-going wave seafloor node data in the frequency-wavenumber domain using Fourier transform.

11. The seafloor node data free surface multiple suppression device according to claim 10, wherein, The interpolation module performing high-density interpolation on the up-going wave and down-going wave seafloor node data in the frequency-wavenumber domain using Fourier transform includes: Forward-transforming the sparsely sampled wavefield from the sparse spatio-temporal domain to the FKK domain; Setting relevant threshold values and extracting the effective information of the wavefield through an iterative method for high-density interpolation; Inverse-transforming the up-going wave and down-going wave back to the high-density spatially sampled spatio-temporal domain.

12. The free surface multiple suppression device for seafloor node data according to claim 9, wherein The multiple wave separation module separates the multiple waves according to the periodic characteristics of the wavefield incident angle variation by performing three-dimensional Taup transformation on the P-component and Z-component of the multiple waves respectively.

13. A computer device, characterized in that, Including: A memory storing a computer program; A processor for executing the computer program to implement the method for suppressing free-surface multiple waves of seafloor node data according to any one of claims 1 - 8.

14. A computer program product, comprising a computer program, characterized in that, The computer program, when executed by the processor, implements the method for suppressing free-surface multiple waves of seafloor node data according to any one of claims 1 - 8.

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