Multiple wave prediction method and device for converted wave free interface, equipment and medium

Abstract

The invention provides a multiple prediction method and device for a converted wave free interface, equipment and a medium, and belongs to the field of seismic data processing. The method comprises the following steps: acquiring a seismic signal, and extracting a longitudinal wave component downlink wave record of the seismic signal; determining a downlink wave imaging data volume according to the downlink wave record of the longitudinal wave component based on Kirchhoff offset; based on Kirchhoff demigration, determining a longitudinal wave component demigration seismic record according to the downlink wave imaging data volume, and taking the longitudinal wave component demigration seismic record as a free interface multiple prediction factor; determining a free interface factor based on the longitudinal wave component demigration seismic record and a free interface preset reflection coefficient; and constructing a free interface multiple prediction model based on the free interface factor and the free interface multiple prediction factor. According to the method, all free interface multiple components in converted wave data can be accurately predicted, so that the multiple elimination precision can be further improved.

Description

Technical Field

[0001] The present invention relates to the field of seismic data processing, and in particular to a method for predicting multiple waves of a converted wave free interface, a device for predicting multiple waves of a converted wave free interface, an electronic device and a computer-readable storage medium. Background Art

[0002] In order to obtain high-quality offshore seismic data with wide azimuth, high coverage and small facet characteristics, Ocean Bottom Nodes (OBN) seismic acquisition has developed rapidly in my country's offshore seismic exploration. Since the sea surface can be approximated as a free interface (reflection coefficient close to -1), in the converted wave components X and Y obtained by OBN exploration, the longitudinal wave energy reflected downward from the sea surface will be reflected back by the underground interface, and will form free interface multiple waves with amplitudes much larger than interlayer multiple waves (downward reflection position at the seabed or its lower interface) and belonging to the converted wave type. Given that the seismic signal mainly used in oil and gas exploration is a single reflection, the prediction and suppression of free interface multiple waves of converted wave components X and Y have become key issues in OBN data processing.

[0003] In recent years, the free-interface multiple attenuation method (SRME) based on feedback loop theory has made great progress. It can effectively suppress the multiple wave components in seismic records without any prior information. It has become one of the preferred methods for two-dimensional seismic data processing and has been extended to the multiple wave suppression of three-dimensional conventional streamer data. However, this method has encountered severe challenges in the processing of OBN converted wave data. Since the seismic signal receiving equipment is arranged on the seabed, OBN acquisition cannot receive the primary reflection wave from the seabed (for the seabed without illumination). In addition, due to the use of an observation system with the characteristics of "few channels and multiple shots", the coverage of the middle and shallow parts of the received data is low and uneven, and even the reflection signal of some shallow strata is missing. This seriously limits the application effect of the data-driven three-dimensional SRME method. The lack of reflection signals will seriously affect the prediction accuracy of multiple waves. Not only can the multiple waves related to the seabed and shallow interface not be predicted, but also obvious spatial aliasing will be generated, thereby affecting the multiple wave removal effect of the converted wave component of the OBN data. Summary of the invention

[0004] The purpose of the present invention is to provide a method, device, equipment and medium for predicting multiple waves of a converted wave free interface, so as to solve the problem that the existing methods cannot accurately predict multiple waves.

[0005] In order to achieve the above object, on the one hand, the present invention provides a method for predicting multiple waves of a converted wave free interface, the method comprising: Acquire seismic signals and extract down-going wave records of longitudinal wave components of seismic signals; Based on Kirchhoff migration, the downgoing wave imaging data volume is determined according to the downgoing wave record of the longitudinal wave component; Based on Kirchhoff de-migration, the P-wave component de-migration seismic record is determined according to the down-going wave imaging data volume, and the P-wave component de-migration seismic record is used as the free interface multiple wave prediction factor; Determine the free interface factor based on the P-wave component back-migration seismic record and the preset reflection coefficient of the free interface; Based on the free interface factor and the free interface multiple wave prediction factor, a free interface multiple wave prediction model is constructed, and the free interface multiple wave prediction model is used to output corresponding multiple wave records according to the input converted wave component data.

[0006] Preferably, the method further comprises: Acquiring converted wave component data to be predicted; The converted wave component data to be predicted is input into the free interface multiple wave prediction model to obtain the multiple wave records.

[0007] Preferably, extracting the downgoing wave record of the longitudinal wave component of the seismic signal comprises: Extract P component data and Z component data from seismic signals; Determine a matching factor according to the P component data and the Z component data; The downgoing wave record of the longitudinal wave component is determined based on the P component data, the Z component data and the matching factor.

[0008] Preferably, based on Kirchhoff migration, according to the downgoing wave record of the longitudinal wave component, determining the downgoing wave imaging data volume includes: Based on Kirchhoff migration, a computational model for downlink wave imaging data volume is constructed; The downgoing wave record of the longitudinal wave component is input into the downgoing wave imaging data volume calculation model to obtain the downgoing wave imaging data volume.

[0009] Preferably, based on Kirchhoff de-migration, the longitudinal wave component de-migration seismic record is determined according to the down-going wave imaging data volume, including: Based on Kirchhoff de-migration, a calculation model for de-migration seismic records is constructed; The downlink wave imaging data volume is input into the anti-migration seismic record calculation model to obtain the longitudinal wave component anti-migration seismic record.

[0010] Preferably, the free interface factor is determined based on the P-wave component de-migration seismic record and the preset reflection coefficient of the free interface, including: Extract seismic wavelets from the P-wave component back-migration seismic records; Transform the seismic wavelet from the time domain to the frequency domain to obtain the frequency domain seismic wavelet; Phase correction is performed based on the frequency-domain seismic wavelet and the preset reflection coefficient of the free interface to obtain the free interface factor.

[0011] Preferably, the free interface multiple wave prediction model is expressed as: ;

[0012] In the formula, Free-interface multiple records for predicted converted-wave component data, is the input converted wave component data, is the free interface factor, is the free interface multiple wave prediction factor, x s and y s represents the spatial coordinates of the shot point, x r and y r represents the spatial coordinates of the receiving point, f is the frequency, x k and y k Indicates the wave field involved in the summation operation X The receiving point and H The spatial coordinates of the hit point.

[0013] On the other hand, the present invention further provides a device for predicting multiple waves of a converted wave free interface, which is used to implement the above-mentioned method for predicting multiple waves of a converted wave free interface, and the device comprises: A down-going wave extraction module is used to obtain seismic signals and extract down-going wave records of longitudinal wave components of seismic signals; A longitudinal wave migration processing module is used to determine a downgoing wave imaging data volume based on the downgoing wave record of the longitudinal wave component based on Kirchhoff migration; The first factor determination module is used to determine the P-wave component de-migration seismic record based on Kirchhoff de-migration and the down-going wave imaging data volume, and use the P-wave component de-migration seismic record as a free interface multiple wave prediction factor; A second factor determination module is used to determine the free interface factor based on the P-wave component back-migration seismic record and the preset reflection coefficient of the free interface; The prediction model building module is used to build a free interface multiple wave prediction model based on a free interface factor and a free interface multiple wave prediction factor.

[0014] On the other hand, the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for predicting multiple waves of a converted wave free interface when executing the computer program.

[0015] On the other hand, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for predicting multiple waves of a converted wave free interface.

[0016] Through the above technical solution, the present invention has at least the following technical effects: The present invention can accurately predict all free interface multiple wave components in converted wave data, thereby further improving the precision of eliminating multiple waves.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 is a flow chart of a method for predicting multiple waves of a converted wave free interface provided by one embodiment of the present invention; Figure 2 It is a "straight ray" model ray tracing process of pre-stack time mirror migration of down-going wave records of longitudinal wave components provided by one embodiment of the present invention; Figure 3 A ray tracing process of Kirchhoff demigration in the time domain of a longitudinal wave component is provided in one embodiment of the present invention; Figure 4 It is an example of a common receiving point gather of P component data provided by one embodiment of the present invention; Figure 5 An example of a common receiving point gather of a downlink wave of a longitudinal wave component extracted according to an embodiment of the present invention; Figure 6 It is a down-going wave imaging data volume of a longitudinal wave component provided by one embodiment of the present invention; Figure 7 An example of a P-wave component de-migration seismic record constructed by time-domain Kirchhoff de-migration provided by an embodiment of the present invention; Figure 8 It is an example of the original converted wave common receiving point gather provided by one embodiment of the present invention; Fig. 9 is an example of a predicted converted wave free interface multiple wave record provided by one embodiment of the present invention; Fig.10 It is a block diagram of a multiple wave prediction device for a converted wave free interface provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0019] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0021] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0022] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] Embodiment 1 It should be noted that Sea Area A is a shallow water area with a relatively flat seabed and a water depth of 50 to 60 m. The air gun source towed at the stern continuously excites seismic waves, and the seismic signals are received by using Ocean Bottom Nodes (OBN). During the seismic acquisition process, 6 receiving lines with a total of 4020 nodes were first laid out on the seabed, and seismic signals were excited in sequence through 24 shot lines. The spacing between the receiving lines and the shot lines was 200 m and 50 m, respectively, and the directions of the two were parallel to each other. The sampling interval and record length of the seismic data were 0.004 seconds and 6 seconds, respectively. Since both the sea surface and the seabed are strong wave impedance interfaces, there are a large number of free interface multiple waves with large amplitudes in the acquired converted wave data, which seriously affects the imaging quality of the underground structure and will mislead the subsequent geological interpretation and analysis.

[0024] Figure 1 FIG. 1 is a flow chart of a method for predicting multiple waves of a converted wave free interface provided by an embodiment of the present invention. Figure 1 As shown, this embodiment provides a method for predicting multiple waves of a converted wave free interface, the method comprising: Step S101: Acquire seismic signals and extract downgoing wave records of longitudinal wave components of seismic signals.

[0025] In this embodiment, extracting the downgoing wave record of the longitudinal wave component of the seismic signal includes: Step a01: extracting P component data and Z component data from the seismic signal; Step a02: Determine a matching factor based on the P component data and the Z component data; Step a03: Determine the downgoing wave record of the longitudinal wave component based on the P component data, the Z component data and the matching factor.

[0026] During the OBN exploration process, the pressure detector and velocity detector are placed directly at the same location on the seabed and receive seismic signals at the same time, so that P component data and Z component data can be obtained respectively. In the P component data and the Z component data, the polarity of the upgoing wave response is the same, and the polarity of the downgoing wave response is opposite. Therefore, by "subtracting" the two, the purpose of extracting the downgoing wave and suppressing the upgoing wave can be achieved.

[0027] Since there is a significant difference in amplitude between the P component data and the Z component data, the least square filtering technology is required. For the adaptive subtraction processing based on the L2 norm, the matching factor is determined by minimizing the square of the error energy e in the following formula.

[0028] (1);

[0029] Wherein, vector p is the P component data, vector z is the Z component data, and * is the convolution operation. The matching factor a can be obtained by solving equation (1). When the length of the matching factor a is 1, the solution of the linear equation group can be avoided, and the calculation formula of the matching factor can be directly given.

[0030] (2);

[0031] Where a represents a matching factor of length 1, and the superscript “T” represents the transpose operation of the matrix.

[0032] Substituting the matching factor a into the following formula can realize the extraction of the downlink wave. The corresponding calculation formula is: (3);

[0033] In the formula, d ( i,t ) represents the extracted down-going wave record of the longitudinal wave component, p ( i,t ) is the P component data, z ( i,t ) is the Z component data, i is the channel number of the earthquake signal, t For traveling.

[0034] In this embodiment, Figure 4 For the P component data common receiving point gather, by simultaneously performing P and Z adaptive subtraction processing of formula (2) and formula (3), we can obtain Figure 5 The P-wave component is shown in the downgoing wave record.

[0035] Step S102: Based on Kirchhoff migration, a downgoing wave imaging data volume is determined according to the downgoing wave record of the longitudinal wave component.

[0036] In this embodiment, based on Kirchhoff migration, according to the downgoing wave record of the longitudinal wave component, the downgoing wave imaging data volume is determined, including: Step b01: constructing a downlink wave imaging data volume calculation model based on Kirchhoff migration; Step b02: inputting the downgoing wave record of the longitudinal wave component into the downgoing wave imaging data volume calculation model to obtain the downgoing wave imaging data volume.

[0037] Kirchhoff migration is the most commonly used migration imaging method in production. In the case of a migration velocity field, it can realize the process of generating seismic profiles using pre-stack seismic data.

[0038] Among them, Kirchhoff migration can be expressed as an integral process in the following form: (4);

[0039] In the formula, I ( η ) represents the offset profile, η is the coordinate of the profile sample point, ξ For a gun - check s , r )’s coordinates; w m ( ξ , η ) is the weight factor of Kirchhoff integral shift, d ( ξ , t ) is a time domain earthquake record; ds represents the integral bin, It represents the sum of the travel time of the ray from the shot point to the imaging point and from the imaging point to the detection point.

[0040] In order to realize the time domain mirror migration based on the downlink wave, the Kirchhoff prestack time migration in the shot gather domain is studied in detail. ξThe down-going wave recording shot gather is used instead, and the migration result is a data in the imaging gather, that is, the down-going wave imaging data volume calculation model is: (5);

[0041] In the formula, g i ( η ) is the i The down-going wave imaging data volume after the shot record migration, d i ( j , t ) is the downgoing wave record shot gather of the longitudinal wave component in the time domain, i For the gun number, j For the road name, J is the total number of channels, η is the coordinate of the profile sample point, is the weight factor of the Kirchhoff integral shift, ds is the integral bin, It represents the sum of the travel time of the ray from the shot point to the imaging point and from the imaging point to the detection point. s i For the i A gun point, r j For the j A detection point.

[0042] In order to image the downgoing wave (ghost wave reflected from the sea surface), the detection point on the seabed needs to be projected to a symmetrical position above the sea surface, such as Figure 3 As shown, the detection point r j Projection above the sea , and then calculate the Kirchhoff weight factor and travel time based on the new receiver position, so as to achieve imaging of the seabed and underlying strata. Figure 3 middle, S ( x k , y k )and G ( x r , y r ) represent the spatial coordinates of the shot point and the detection point respectively.

[0043] Mirror Kirchhoff prestack time migration uses a ray tracing process of the "straight ray" model (such as Figure 2 ), Figure 2 middle, S m Indicates the gun point. G nrepresents the detection point, so the weight factor in formula (5) W M ( s i , , η ) and travel time τ( s i , , η ) is significantly simplified, and the two can be expressed as:

[0044] (6);

[0045] In the formula, For detection point r j The projection of v 0 ( η ) is the displacement speed of the primary wave, cos θ is the tilt factor, l 0 is the distance from the shot point to the imaging point, l is the distance from the imaging point to the shot point, r 0 It represents the straight-line distance from the shot point to the reflection point. r Indicates the straight-line distance from the reflection point to the detection point.

[0046] by Figure 5 The longitudinal wave component downlink record is shown d ( i,j ) is the input, Figure 4 and Figure 5 The horizontal axis is the shot number (ShotNo.), and the vertical axis is the two-way travel time (TWT) of the seismic wave. According to formula (4), formula (5) and formula (6), the shot domain Kirchhoff prestack time mirror migration processing can be obtained. Figure 6 Downward-wave imaging data volume of the longitudinal wave component is shown.

[0047] Step S103: Based on Kirchhoff de-migration, the P-wave component de-migration seismic record is determined according to the down-going wave imaging data volume, and the P-wave component de-migration seismic record is used as a free interface multiple wave prediction factor.

[0048] In this embodiment, based on Kirchhoff demigration, the longitudinal wave component demigration seismic record is determined according to the downlink wave imaging data volume, including: Step c01: constructing a calculation model for de-migration seismic records based on Kirchhoff de-migration; Step c02: Input the downlink wave imaging data volume into the anti-migration seismic record calculation model to obtain the longitudinal wave component anti-migration seismic record.

[0049] Prestack time migration profile generated by formula (4) I ( η ) is used as input, and the “straight ray” model ray tracing process of prestack time migration is introduced. Then the calculation model of the anti-migration seismic record in the time domain can be expressed as: (7);

[0050] In the formula, is the de-migration record, that is, the de-migration seismic record of the longitudinal wave component. x k and y k represents the spatial coordinates of the demigrated shot point, x r and y r represents the spatial coordinates of the receiving point for de-migration, η is the coordinates of the profile sample point, ds represents the integral surface element; is the weight factor for Kirchhoff demigration, Indicates that the ray passes through the gun point to η point, η The sum of the travel times from point A to point B.

[0051] When multiple wave prediction is performed for a data in a shot gather, x r and y r is a fixed value, and x k and y k is changing, so Represents the common receiver gather record; it should be noted that the integral weight factor in the de-migration process It is somewhat different from time migration imaging, which should be calculated using a more accurate Kirchhoff integrated diffraction stacking method (such as Figure 3 as shown).

[0052] (8);

[0053] In the formula, l 0 is the propagation distance of the incident ray (the distance from the shot point to the imaging point), l is the propagation distance of the diffraction ray (the distance from the imaging point to the shot point); θ 0 and θ They are l 0 、l The angle with the surface element normal vector n; v ( η) represents the seismic wave velocity.

[0054] by Figure 6 The downlink imaging data volume of the longitudinal wave component shown is input, Figure 6 The horizontal distance in the horizontal direction is the horizontal position (km), and the vertical direction is the two-way travel time (TWT) of the seismic wave. The time-domain Kirchhoff DM based on formulas (7) and (8) is constructed as follows: Figure 7 The P-wave component de-migration seismic record shown, Figure 7-Figure 9 The horizontal direction is the detection point number (Trace No.), and the vertical direction is the two-way travel time (TWT) of the seismic wave. The longitudinal wave component anti-migration seismic record is used as a free interface multiple wave prediction factor to participate in the free interface multiple wave prediction of the OBN data conversion wave component.

[0055] Step S104: Determine the free interface factor based on the P-wave component de-migration seismic record and the preset reflection coefficient of the free interface.

[0056] In this embodiment, based on the P-wave component back-migration seismic record and the preset reflection coefficient of the free interface, the free interface factor is determined, including: Step d01: extracting seismic wavelets from the P-wave component de-migration seismic records; Step d02: transform the seismic wavelet from the time domain to the frequency domain to obtain the frequency domain seismic wavelet; Step d03: Perform phase correction based on the frequency domain seismic wavelet and the preset reflection coefficient of the free interface to obtain the free interface factor.

[0057] In this embodiment, the calculation expression of the free interface factor is: (9);

[0058] In the formula, is the free interface factor, (-1) is the preset reflection coefficient of the free interface (the reflection coefficient of the free interface (sea surface) in offshore seismic exploration), The seismic wavelet extracted from the seismic record based on the P-wave component de-migration w ( t ), f Indicates frequency.

[0059] Step S105: constructing a free interface multiple wave prediction model based on the free interface factor and the free interface multiple wave prediction factor, wherein the free interface multiple wave prediction model is used to output corresponding multiple wave records according to the input converted wave component data.

[0060] In this embodiment, the converted wave component data separated by wave field and the P-wave component back-migration seismic record constructed by time-domain Kirchhoff back-migration are used as the prediction factors required for free interface multiple wave prediction. Both are transformed into the frequency domain and substituted into the three-dimensional free interface multiple wave prediction equation. The free interface multiple wave prediction process of the converted wave component is: (10);

[0061] In the formula, Free-interface multiple records for predicted converted-wave component data, is the input converted wave component data, is the free interface multiple wave prediction factor, x s and y s represents the spatial coordinates of the shot point, x r and y r represents the spatial coordinates of the receiving point, f is the frequency, x k and y k Indicates the wave field involved in the summation operation X The receiving point and H The spatial coordinates of the hit point.

[0062] The free interface factor calculated by introducing equation (9) is , then formula (10) can further obtain the free interface multiple wave prediction model, which is:

[0063] (11);

[0064] Formula (11) is a multiple wave prediction model that introduces the free interface multiple wave prediction factor and the free interface factor. This process is carried out in the frequency domain. After obtaining the multiple wave records based on Formula (11), the multiple waves in the converted wave component data X can be eliminated by the adaptive attenuation method.

[0065] As a further optimization of this embodiment, the method further includes: Step e01: obtaining the converted wave component data to be predicted; Step e02: Input the converted wave component data to be predicted into the free interface multiple wave prediction model to obtain the multiple wave record.

[0066] by Figure 8 The converted wave component data shown in the figure is taken as input (as the converted wave component data to be predicted), and the free interface multiple wave prediction of the converted wave component of the OBN data is realized based on formula (11), and the following is obtained: Fig. 9 The multiple wave records shown in Figure 2 contain rich multiple wave information. By comparison, we can see that Figure 8 and Fig. 9 The travel times of the multiple wave events in the two records are basically consistent, which proves the effectiveness of the converted wave free interface multiple wave prediction method.

[0067] The prediction method of this embodiment realizes the prediction of three-dimensional free interface multiple waves of the converted wave component of OBN data, effectively solves the problem that the conventional streamer SRME method cannot be applied to such data, and can significantly improve the multiple wave suppression effect of the converted wave component data of OBN data. Compared with the multiple wave prediction technology based on wave field continuation, this method has obvious accuracy advantages. This is because the former can only predict part of the free interface multiple waves - ghost waves and seabed multiple waves (full-range multiple waves of the seabed and slightly bent multiple waves related to the seabed), while this method can predict all free interface multiple wave components in the converted wave data, so it will inevitably further improve the accuracy of multiple wave removal.

[0068] Embodiment 2 Fig.10 is a block diagram of a multiple wave prediction device for a converted wave free interface provided by an embodiment of the present invention, such as Fig.10 As shown, based on the same inventive concept as in the first embodiment, this embodiment further provides a multiple wave prediction device for a converted wave free interface, the device is used to implement the multiple wave prediction method for a converted wave free interface in the first embodiment, and the device comprises: A down-going wave extraction module is used to obtain seismic signals and extract down-going wave records of longitudinal wave components of seismic signals; A longitudinal wave migration processing module is used to determine a downgoing wave imaging data volume based on the downgoing wave record of the longitudinal wave component based on Kirchhoff migration; The first factor determination module is used to determine the P-wave component de-migration seismic record based on Kirchhoff de-migration and the down-going wave imaging data volume, and use the P-wave component de-migration seismic record as a free interface multiple wave prediction factor; A second factor determination module is used to determine the free interface factor based on the P-wave component back-migration seismic record and the preset reflection coefficient of the free interface; The prediction model building module is used to build a free interface multiple wave prediction model based on a free interface factor and a free interface multiple wave prediction factor.

[0069] Based on the same inventive concept as in the first embodiment, this embodiment further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for predicting multiple waves of a converted wave free interface when executing the computer program.

[0070] Based on the same inventive concept as the first embodiment, this embodiment further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the above-mentioned method for predicting multiple waves of a converted wave free interface is implemented.

[0071] The prediction method of this embodiment realizes the prediction of three-dimensional free interface multiple waves of the converted wave component of OBN data, effectively solves the problem that the conventional streamer SRME method cannot be applied to such data, and can significantly improve the multiple wave suppression effect of the converted wave component data of OBN data. Compared with the multiple wave prediction technology based on wave field continuation, this method has obvious accuracy advantages. This is because the former can only predict part of the free interface multiple waves - ghost waves and seabed multiple waves (full-range multiple waves of the seabed and slightly bent multiple waves related to the seabed), while this method can predict all free interface multiple wave components in the converted wave data, so it will inevitably further improve the accuracy of multiple wave removal.

[0072] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt 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 codes.

[0073] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the 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 generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0074] 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, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0075] These computer program instructions can 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, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0076] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0077] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0078] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. 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 technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0079] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0080] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for predicting multiple waves of a converted wave free interface, characterized in that: The method comprises: Acquire seismic signals and extract down-going wave records of longitudinal wave components of seismic signals; Based on Kirchhoff migration, the downgoing wave imaging data volume is determined according to the downgoing wave record of the longitudinal wave component; Based on Kirchhoff de-migration, the P-wave component de-migration seismic record is determined according to the down-going wave imaging data volume, and the P-wave component de-migration seismic record is used as the free interface multiple wave prediction factor; Determine the free interface factor based on the P-wave component back-migration seismic record and the preset reflection coefficient of the free interface; Based on the free interface factor and the free interface multiple wave prediction factor, a free interface multiple wave prediction model is constructed, and the free interface multiple wave prediction model is used to output corresponding multiple wave records according to the input converted wave component data.

2. The method according to claim 1, characterized in that The method further comprises: Acquiring converted wave component data to be predicted; The converted wave component data to be predicted is input into the free interface multiple wave prediction model to obtain the multiple wave records.

3. The method according to claim 1, characterized in that Extract the downgoing wave record of the longitudinal component of the seismic signal, including: Extract P component data and Z component data from seismic signals; Determine a matching factor according to the P component data and the Z component data; The downgoing wave record of the longitudinal wave component is determined based on the P component data, the Z component data and the matching factor.

4. The method according to claim 1, characterized in that: Based on Kirchhoff migration and the downgoing wave record of the longitudinal wave component, the downgoing wave imaging data volume is determined, including: Based on Kirchhoff migration, a computational model for downlink wave imaging data volume is constructed; The downgoing wave record of the longitudinal wave component is input into the downgoing wave imaging data volume calculation model to obtain the downgoing wave imaging data volume.

5. The method according to claim 1, characterized in that Based on Kirchhoff de-migration, the P-wave component de-migration seismic records are determined according to the down-going wave imaging data volume, including: Based on Kirchhoff de-migration, a calculation model for de-migration seismic records is constructed; The downlink wave imaging data volume is input into the anti-migration seismic record calculation model to obtain the longitudinal wave component anti-migration seismic record.

6. The method according to claim 1, characterized in that Based on the P-wave component back-migration seismic records and the preset reflection coefficient of the free interface, the free interface factor is determined, including: Extract seismic wavelets from the P-wave component back-migration seismic records; Transform the seismic wavelet from the time domain to the frequency domain to obtain the frequency domain seismic wavelet; Phase correction is performed based on the frequency-domain seismic wavelet and the preset reflection coefficient of the free interface to obtain the free interface factor.

7. The method according to claim 2, characterized in that: The expression of the free interface multiple wave prediction model is: ； In the formula, Free-interface multiple records for predicted converted-wave component data, is the input converted wave component data, is the free interface factor, is the free interface multiple wave prediction factor, x s and y s represents the spatial coordinates of the shot point, x r and y r represents the spatial coordinates of the receiving point, f is the frequency, x k and y k Indicates the wave field involved in the summation operation X The receiving point and H The spatial coordinates of the hit point.

8. A multiple wave prediction device for a converted wave free interface, used to implement the multiple wave prediction method for a converted wave free interface according to any one of claims 1 to 7, characterized in that: The device comprises: A down-going wave extraction module is used to obtain seismic signals and extract down-going wave records of longitudinal wave components of seismic signals; A longitudinal wave migration processing module is used to determine a downgoing wave imaging data volume based on the downgoing wave record of the longitudinal wave component based on Kirchhoff migration; The first factor determination module is used to determine the P-wave component de-migration seismic record based on Kirchhoff de-migration and the down-going wave imaging data volume, and use the P-wave component de-migration seismic record as a free interface multiple wave prediction factor; A second factor determination module is used to determine the free interface factor based on the P-wave component back-migration seismic record and the preset reflection coefficient of the free interface; The prediction model building module is used to build a free interface multiple wave prediction model based on a free interface factor and a free interface multiple wave prediction factor.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method for predicting multiple waves of a converted wave free interface according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method for predicting multiple waves of a converted wave free interface according to any one of claims 1 to 7 is implemented.

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