CN108387926B - Method and device for determining far-field wavelets of air gun array - Google Patents

Method and device for determining far-field wavelets of air gun array Download PDF

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CN108387926B
CN108387926B CN201810104599.1A CN201810104599A CN108387926B CN 108387926 B CN108387926 B CN 108387926B CN 201810104599 A CN201810104599 A CN 201810104599A CN 108387926 B CN108387926 B CN 108387926B
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CN108387926A (en
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曹明强
丁冠东
陈浩林
毛贺江
张小明
霍立锋
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China National Petroleum Corp
BGP Inc
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
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    • G01V1/133—Generating seismic energy using fluidic driving means, e.g. highly pressurised fluids; using implosion
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    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
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    • G01V1/38—Seismology; Seismic or acoustic prospecting or detecting specially adapted for water-covered areas
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    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V2210/00—Details of seismic processing or analysis
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    • G01V2210/12—Signal generation
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    • G01V2210/1293—Sea
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V2210/00—Details of seismic processing or analysis
    • G01V2210/30—Noise handling
    • G01V2210/32—Noise reduction
    • G01V2210/324—Filtering

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Abstract

The embodiment of the application discloses a method and a device for determining far-field wavelets of an air gun array. The method provides an initial near-field wavelet excited by an air-gun source in an air-gun array and recorded at a receiving point of a near-field detector in a near-field detector set; the method comprises the following steps: determining a filter factor according to the distance between the air gun seismic source and a near-field detector in the near-field detector group and the distance between a virtual image of the air gun seismic source and the near-field detector in the near-field detector group; filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet; and determining the far-field wavelet corresponding to the air gun array according to the target near-field wavelet. The technical scheme provided by the embodiment of the application can improve the precision of the determined far-field wavelet of the air gun array.

Description

Method and device for determining far-field wavelets of air gun array
Technical Field
The application relates to the technical fields of seismic exploration and acquisition of air gun sources, geological survey and the like in marine environments and inland lakes, in particular to a method and a device for determining far-field wavelets of an air gun array.
Background
The air gun seismic source has the characteristics of stable and reliable performance, safety, environmental protection and the like, and is the most widely applied seismic source in marine seismic exploration at present. When the air gun seismic source is excited, high-pressure gas in the air gun is instantaneously released and generates a large-volume bubble, and along with the damping type periodic motion of the bubble, far-field wavelets of the air gun array are formed and spread to the periphery. The designed air gun array is limited by field construction conditions and is difficult to achieve circular symmetry in a strict sense but has a certain length and width, so that the air gun array does not meet the assumed conditions of a point source, namely far-field wavelets of the air gun array do not spread to the periphery in a spherical mode, the energy of the far-field wavelets of the air gun array changes along with the changes of a horizontal azimuth angle and a vertical azimuth angle, and the far-field wavelets are generally called as the directional characteristics of the far-field wavelets of the air gun array. The directivity of the far-field wavelet of the air gun array is analyzed, the distribution condition of the far-field wavelet energy in different frequency ranges in a three-dimensional space can be determined, the air gun array for marine seismic exploration is designed and optimized according to the distribution condition, and obviously, the research is also significant for recovering the true amplitude in the processing of marine seismic exploration data.
At present, researchers usually directly determine the far-field wavelet of the air gun array by using the simulated wavelet and analyze the directivity of the far-field wavelet of the air gun array, however, the simulated wavelet is often different from the actual far-field wavelet of the air gun array, and therefore a method for determining the far-field wavelet of the air gun array with higher precision is urgently needed.
Disclosure of Invention
An object of the embodiments of the present application is to provide a method and an apparatus for determining far-field wavelets of an airgun array, so as to improve the accuracy of the determined far-field wavelets of the airgun array.
To solve the above technical problem, an embodiment of the present application provides a method and an apparatus for determining far-field wavelets of an airgun array, which are implemented as follows:
a method of determining a far-field wavelet for an airgun array, the method providing an initial near-field wavelet excited by an airgun source in the airgun array and recorded at a receiving point of a near-field detector in a near-field detector set; the method comprises the following steps:
determining a filter factor according to the distance between the air gun seismic source and a near-field detector in the near-field detector group and the distance between a virtual image of the air gun seismic source and the near-field detector in the near-field detector group;
filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet;
and determining the far-field wavelet corresponding to the air gun array according to the target near-field wavelet.
In a preferred embodiment, the filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet includes:
converting the initial near-field wavelet from a time domain to a frequency domain to obtain an initial near-field wavelet of the frequency domain, and establishing an initial near-field wavelet spectrum matrix according to the initial near-field wavelet of the frequency domain; the initial near-field wavelet spectrum matrix is used for representing an initial near-field wavelet set of a frequency domain recorded by the near-field detector group correspondingly;
and filtering the initial near-field wavelet set represented by the initial near-field wavelet spectrum matrix by using the filtering factor to obtain a filtered initial near-field wavelet set of the frequency domain, and taking the filtered initial near-field wavelet set of the frequency domain as the target near-field wavelet.
In a preferred embodiment, the filter factor is determined by the following formula:
Figure BDA0001567431200000021
wherein A represents the filter factor, rmnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the nth air gun seismic source in the air gun array, (r)g)mnA receiving point representing the mth near-field detector in the near-field detector group and the nth near-field detector in the airgun arrayDistance between virtual images of air gun seismic source, C represents speed of sound wave in water, omega represents angular frequency, i represents imaginary number, i represents angular frequency2＝-1；
Obtaining a target near-field wavelet spectrum matrix for characterizing the initial near-field wavelet set of the filtered frequency domain using the following formula:
X(ω)＝(ATA+λI)-1ATB
wherein X (ω) represents the target near-field wavelet spectral matrix, ATDenotes the transposed matrix of A, λ denotes the stability factor, Nm(ω) represents an initial near-field wavelet of a frequency domain recorded at a receiving point of an mth near-field detector in the near-field detector set, m represents the number of near-field detectors in the near-field detector set, and n represents the number of air gun vibration sources in an air gun array.
In a preferred embodiment, the value of the stability factor is 10-8。
In a preferred scheme, the far-field wavelet corresponding to the air gun array is determined by adopting the following formula:
Figure BDA0001567431200000031
Figure BDA0001567431200000032
wherein the content of the first and second substances,
Figure BDA0001567431200000033
the propagation distance of the far field sub-wave corresponding to the air gun array is R, the vertical azimuth angle is theta, and the horizontal azimuth angle is theta
Figure BDA0001567431200000034
And a far-field wavelet with an angular frequency omega, the vertical azimuth angle theta representing the clip of the propagation direction of the far-field wavelet in a Cartesian coordinate system and the z-axis of the Cartesian coordinate systemAngle, said horizontal azimuth angle is
Figure BDA0001567431200000035
Representing the included angle between the projection of the far-field wavelet propagation direction in the plane xoy of the Cartesian coordinate system and the x axis in the Cartesian coordinate system; r isn(r) represents the distance between the detection point of the far-field wavelet and the nth air gun source in the air gun arrayg)nRepresenting a distance between a detection point of the far-field wavelet and a virtual image of an nth airgun source in the airgun array.
In a preferred scheme, the distance r between the detection point of the far-field wavelet and the kth air gun seismic source in the air gun array is calculated by adopting the following formulak：
Figure BDA0001567431200000036
Wherein x isk、ykAnd zkRespectively representing the coordinates of the k-th air gun source in the directions of an x-axis, a y-axis and a z-axis in a Cartesian coordinate system.
In a preferred scheme, the distance (r) between the detection point of the far-field wavelet and the virtual image of the kth air gun seismic source in the air gun array is calculated by adopting the following formulag)k：
Figure BDA0001567431200000037
Wherein x isk、ykAnd zkRespectively representing the coordinates of the k-th air gun source in the directions of an x-axis, a y-axis and a z-axis in a Cartesian coordinate system.
An apparatus for determining a far-field wavelet for an airgun array, said apparatus providing an initial near-field wavelet excited by an airgun source in the airgun array and recorded at a receiving point of a near-field detector in a near-field detector set; the device comprises: the device comprises a filtering factor determining module, a target near-field wavelet determining module and a far-field wavelet determining module; wherein the content of the first and second substances,
the filter factor determination module is used for determining a filter factor according to the distance between the air gun seismic source and a near-field detector in the near-field detector group and the distance between a virtual image of the air gun seismic source and the near-field detector in the near-field detector group;
the target near-field wavelet determining module is used for filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet;
and the far-field wavelet determining module is used for determining the far-field wavelet corresponding to the air gun array according to the target near-field wavelet.
In a preferred embodiment, the target near-field wavelet determining module is configured to convert the initial near-field wavelet from a time domain to a frequency domain to obtain an initial near-field wavelet of the frequency domain, and establish an initial near-field wavelet matrix according to the initial near-field wavelet of the frequency domain, where the initial near-field wavelet matrix is used to represent an initial near-field wavelet set of the frequency domain recorded by the near-field detector set, and the initial near-field wavelet set represented by the initial near-field wavelet matrix is filtered by using the filtering factor to obtain a filtered initial near-field wavelet set of the frequency domain, and the filtered initial near-field wavelet set of the frequency domain is used as the target near-field wavelet.
In a preferred embodiment, the filtering factor determining module is configured to determine the filtering factor by using the following formula:
Figure BDA0001567431200000041
wherein A represents the filter factor, rmnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the nth air gun seismic source in the air gun array, (r)g)mnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the virtual image of the nth air gun seismic source in the air gun array, C representing the speed of sound waves in water, omega representing angular frequency, i representing an imaginary number2＝-1；
The target near-field wavelet determining module is used for obtaining a target near-field wavelet spectrum matrix of the initial near-field wavelet set for representing the filtered frequency domain by adopting the following formula:
X(ω)＝(ATA+λI)-1ATB
Figure BDA0001567431200000042
wherein X (ω) represents the target near-field wavelet spectral matrix, ATDenotes the transposed matrix of A, λ denotes the stability factor, Nm(ω) represents an initial near-field wavelet of a frequency domain recorded at a receiving point of an mth near-field detector in the near-field detector set, m represents the number of near-field detectors in the near-field detector set, and n represents the number of air gun vibration sources in an air gun array.
According to the technical scheme provided by the embodiment of the application, the method and the device for determining the far-field wavelet of the air gun array in the embodiment of the application can determine the filter factor according to the distance between the air gun seismic source and the near-field detector in the near-field detector group and the distance between the virtual image of the air gun seismic source and the near-field detector in the near-field detector group; filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet; the far-field wavelet corresponding to the airgun array may be determined based on the target near-field wavelet. Compared with the prior art, the method provided by the embodiment of the application utilizes the actually measured near-field wavelet to simulate the far-field wavelet of the air gun array, the simulation result has scientific basis, and meanwhile, the near-field wavelet is subjected to filtering processing through the determined filtering factor so as to eliminate the virtual reflection of the air gun seismic source and the influence of other air gun seismic sources in the air gun array except the air gun seismic source, and therefore the precision of the determined air gun array far-field wavelet is improved.
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In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without any creative effort.
FIG. 1 is a schematic diagram of the distribution of an air gun array and detector array in an embodiment of the present application;
FIG. 2 is a flow diagram of an embodiment of a method of determining far-field wavelets for an airgun array according to the present application;
FIG. 3 is a schematic diagram of an initial near-field wavelet recorded at a receiving point of each near-field detector in a near-field detector group in an embodiment of the present application;
FIG. 4 is a schematic diagram of far-field wavelets with different vertical azimuths in an embodiment of the present application;
FIG. 5 is a block diagram illustrating the components of one embodiment of the apparatus for determining far-field wavelets for an airgun array of the present application;
FIG. 6 is a block diagram illustrating the components of another embodiment of the apparatus for determining far-field wavelets for an airgun array according to the present application.
Detailed Description
The embodiment of the application provides a method and a device for determining far-field wavelets of an air gun array.
In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The embodiment of the application provides a method for determining far-field wavelets of an air gun array. The method of determining the far-field wavelet of an airgun array provides an initial near-field wavelet that is excited by an airgun source in the airgun array and recorded at a receiving point of a near-field detector in a near-field detector set.
In this embodiment, the airgun array may include a plurality of airgun sources, and the near-field detector may include a plurality of near-field detectors. Wherein the near-field detector may be disposed at a position 1 meter directly above the air gun seismic source. For example, FIG. 2 is a schematic diagram of the distribution of air gun arrays and detector arrays in an embodiment of the present application. N1, N2, N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16, and N17 in fig. 1 respectively denote near-field detectors in the near-field detector group. As shown in fig. 1, 29 air gun sources are included in the air gun array, and 17 near field detectors are included in the near field detector group.
In this embodiment, the initial near-field wavelet at the receiving point of each near-field detector in the near-field detector group may be a result of superposition of near-field wavelets excited by each air-gun source in the air-gun array and recorded at the receiving point of the near-field detector.
FIG. 2 is a flow chart of an embodiment of a method of determining far-field wavelets for an airgun array according to the present application. As shown in FIG. 2, the method for determining far-field wavelets of an airgun array comprises the following steps.
Step S101: and determining a filter factor according to the distance between the air gun seismic source and the near-field detector in the near-field detector group and the distance between a virtual image of the air gun seismic source and the near-field detector in the near-field detector group.
In this embodiment, the filter factor may be determined using the following equation:
Figure BDA0001567431200000061
wherein A represents the filter factor, rmnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the nth air gun seismic source in the air gun array, (r)g)mnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the virtual image of the nth air gun seismic source in the air gun array, C representing the speed of sound waves in water, omega representing angular frequency, i representing an imaginary number2＝-1。
Step S102: and carrying out filtering processing on the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet.
In this embodiment, the filtering processing is performed on the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet, and specifically, the method may include converting the initial near-field wavelet from a time domain to a frequency domain by using a fourier transform method to obtain an initial near-field wavelet of the frequency domain, and establishing an initial near-field wavelet spectrum matrix according to the initial near-field wavelet of the frequency domain; and the initial near-field wavelet spectrum matrix is used for representing an initial near-field wavelet set of a frequency domain recorded correspondingly by the near-field detector group. The initial near-field wavelet set represented by the initial near-field wavelet spectrum matrix can be filtered by using the filtering factor to obtain a filtered initial near-field wavelet set of the frequency domain, and the filtered initial near-field wavelet set of the frequency domain is used as the target near-field wavelet.
In this embodiment, the following formula may be used to obtain a target near-field wavelet spectrum matrix for characterizing the initial near-field wavelet set of the filtered frequency domain:
X(ω)＝(ATA+λI)-1ATB
wherein X (ω) represents the target near-field wavelet spectral matrix, A represents the filter factor, ATDenotes the transposed matrix of A, λ denotes the stability factor, Nm(ω) represents an initial near-field wavelet of a frequency domain recorded at a receiving point of an mth near-field detector in the near-field detector set, m represents the number of near-field detectors in the near-field detector set, and n represents the number of air gun vibration sources in an air gun array.
In this embodiment, the value of the stability factor may be 10-8。
Step S103: and determining the far-field wavelet corresponding to the air gun array according to the target near-field wavelet.
In this embodiment, the far-field wavelet corresponding to the airgun array may be determined using the following formula:
Figure BDA0001567431200000072
Figure BDA0001567431200000073
wherein the content of the first and second substances,
Figure BDA0001567431200000074
the propagation distance of the far field sub-wave corresponding to the air gun array is R, the vertical azimuth angle is theta, and the horizontal azimuth angle is theta
Figure BDA0001567431200000075
And far-field wavelets with angular frequency ω; the resulting far-field wavelet is now in the frequency domain. The vertical azimuth angle theta represents an included angle between the far-field wavelet propagation direction in the Cartesian coordinate system and the z axis of the Cartesian coordinate system, and the horizontal azimuth angle theta is
Figure BDA0001567431200000076
Representing the included angle between the projection of the far-field wavelet propagation direction in the plane xoy of the Cartesian coordinate system and the x axis in the Cartesian coordinate system; r isn(r) represents the distance between the detection point of the far-field wavelet and the nth air gun source in the air gun arrayg)nRepresenting a distance between a detection point of the far-field wavelet and a virtual image of an nth airgun source in the airgun array.
In this embodiment, the following formula may be used to calculate the distance r between the detection point of the far-field wavelet and the kth air gun seismic source in the air gun arrayk：
Figure BDA0001567431200000077
Wherein x isk、ykAnd zkRespectively representing the x-axis, y-axis and k-th air gun seismic source in a Cartesian coordinate systemCoordinates in the z-axis direction.
In this embodiment, the distance (r) between the detection point of the far-field wavelet and the virtual image of the kth air-gun seismic source in the air-gun array can be calculated by using the following formulag)k：
Figure BDA0001567431200000081
Wherein x isk、ykAnd zkRespectively representing the coordinates of the k-th air gun source in the directions of an x-axis, a y-axis and a z-axis in a Cartesian coordinate system.
In this embodiment, the propagation distance of the far-field sub-wave corresponding to the air gun array may be R, the vertical azimuth may be θ, and the horizontal azimuth may be θ by an inverse fourier transform method
Figure BDA0001567431200000082
Far-field wavelet with sum angular frequency omega
Figure BDA0001567431200000083
And converting from the frequency domain to the time domain to obtain the corresponding far-field wavelet of the time domain.
For example, FIG. 3 is a schematic illustration of an initial near-field wavelet recorded at the receiving point of each near-field detector in the near-field detector set of FIG. 1. The abscissa and ordinate in fig. 3 are the number and sampling time of the near-field detector, respectively, and the unit of the sampling time is milliseconds (ms). FIG. 4 is a schematic diagram of far-field wavelets with different vertical azimuth angles in an embodiment of the present application. The abscissa and the ordinate in fig. 3 are the vertical azimuth and the sampling time of the far-field wavelet, respectively, the value range of the vertical azimuth is 0 to 90 °, and the unit of the sampling time is millisecond (ms). FIG. 4 is a schematic diagram of far-field wavelets with different vertical azimuth angles obtained using the method of the present application based on the initial near-field wavelets in FIG. 3.
In the embodiment of the method for determining the far-field wavelet of the air gun array, the filter factor can be determined according to the distance between the air gun seismic source and the near-field detector in the near-field detector group and the distance between the virtual image of the air gun seismic source and the near-field detector in the near-field detector group; filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet; the far-field wavelet corresponding to the airgun array may be determined based on the target near-field wavelet. Compared with the prior art, the method provided by the embodiment of the application utilizes the actually measured near-field wavelet to simulate the far-field wavelet of the air gun array, the simulation result has scientific basis, and meanwhile, the near-field wavelet is subjected to filtering processing through the determined filtering factor so as to eliminate the virtual reflection of the air gun seismic source and the influence of other air gun seismic sources in the air gun array except the air gun seismic source, and therefore the precision of the determined air gun array far-field wavelet is improved.
FIG. 5 is a block diagram illustrating the components of one embodiment of the apparatus for determining far-field wavelets for an airgun array according to the present application. The means for determining the far field wavelet of the airgun array provides a near field wavelet that is excited by an airgun source in the airgun array and recorded at a receiving point in a near field detector bank. As shown in fig. 5, the apparatus for determining far-field wavelets for an airgun array may comprise: a filter factor determination module 100, a target near-field wavelet determination module 200, and a far-field wavelet determination module 300.
The filter factor determination module 100 may be configured to determine a filter factor according to a distance between the air gun seismic source and a near-field detector in the near-field detector set, and a distance between a virtual image of the air gun seismic source and a near-field detector in the near-field detector set.
The target near-field wavelet determining module 200 may be configured to perform filtering processing on the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet.
The far-field wavelet determining module 300 may be configured to determine a far-field wavelet corresponding to the air gun array according to the target near-field wavelet.
In this embodiment, the target near-field wavelet determining module 200 may be configured to convert the initial near-field wavelet from a time domain to a frequency domain to obtain an initial near-field wavelet of the frequency domain, and establish an initial near-field wavelet spectrum matrix according to the initial near-field wavelet of the frequency domain, where the initial near-field wavelet spectrum matrix is used to represent an initial near-field wavelet set of the frequency domain recorded by the near-field detector set correspondingly, and perform filtering processing on the initial near-field wavelet set represented by the initial near-field wavelet spectrum matrix by using the filtering factor to obtain a filtered initial near-field wavelet set of the frequency domain, and use the filtered initial near-field wavelet set of the frequency domain as the target near-field wavelet.
In this embodiment, the filter factor determining module 100 may be configured to determine the filter factor by using the following formula:
Figure BDA0001567431200000091
wherein A represents the filter factor, rmnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the nth air gun seismic source in the air gun array, (r)g)mnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the virtual image of the nth air gun seismic source in the air gun array, C representing the speed of sound waves in water, omega representing angular frequency, i representing an imaginary number2＝-1；
The target near-field wavelet determination module 200 may be configured to derive a target near-field wavelet spectral matrix for characterizing the initial near-field wavelet set of the filtered frequency domain using the following equation:
X(ω)＝(ATA+λI)-1ATB
Figure BDA0001567431200000092
wherein X (ω) represents the target near-field wavelet spectral matrix, ATDenotes the transposed matrix of A, λ denotes the stability factor, Nm(ω) represents an initial near-field wavelet of a frequency domain recorded at a receiving point of an mth near-field detector in the near-field detector group, m represents the number of near-field detectors in the near-field detector group, and n represents an air gun seismic source in an air gun arrayThe number of the cells.
FIG. 6 is a block diagram illustrating the components of another embodiment of the apparatus for determining far-field wavelets for an airgun array according to the present application. As shown in fig. 6, the apparatus for determining far-field wavelets for an airgun array may include a memory, a processor, and a computer program stored on the memory. The memory also stores initial near-field wavelets excited by an air gun seismic source in the air gun array and recorded at the receiving points of near-field detectors in the near-field detector group; the computer program when executed by the processor performs the steps of:
determining a filter factor according to the distance between the air gun seismic source and a near-field detector in the near-field detector group and the distance between a virtual image of the air gun seismic source and the near-field detector in the near-field detector group;
filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet;
and determining the far-field wavelet corresponding to the air gun array according to the target near-field wavelet.
The device embodiment for determining the far-field wavelet of the air gun array corresponds to the method embodiment for determining the far-field wavelet of the air gun array, the technical scheme of the method embodiment for determining the far-field wavelet of the air gun array can be realized, and the technical effect of the method embodiment can be obtained.
In the 90 s of the 20 th century, improvements in a technology could clearly distinguish between improvements in hardware (e.g., improvements in circuit structures such as diodes, transistors, switches, etc.) and improvements in software (improvements in process flow). However, as technology advances, many of today's process flow improvements have been seen as direct improvements in hardware circuit architecture. Designers almost always obtain the corresponding hardware circuit structure by programming an improved method flow into the hardware circuit. Thus, it cannot be said that an improvement in the process flow cannot be realized by hardware physical modules. For example, programmable logic devices
A Programmable Logic Device (PLD), such as a Field Programmable Gate Array (FPGA), is an integrated circuit whose Logic functions are determined by a user programming the Device. A digital system is "integrated" on a PLD by the designer's own programming without requiring the chip manufacturer to design and fabricate application-specific integrated circuit chips. Furthermore, instead of manually manufacturing the integrated circuit chip, the programming is mostly implemented by "logic compiler" software, which is similar to the software compiler used in the program development and writing, and the original code before compiling is written by a specific programming language, which is called hardware description language
(HDL), but HDL is not only one, but many, such as ABEL (advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Central University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, LASPAM, RHDL (Ruby Hardware Description Language), etc., and VHDL (Very-High-speed-Language) and Verilog2 are currently most commonly used. It will also be apparent to those skilled in the art that hardware circuitry that implements the logical method flows can be readily obtained by merely slightly programming the method flows into an integrated circuit using the hardware description languages described above.
Those skilled in the art will also appreciate that, in addition to implementing the controller as pure computer readable program code, the same functionality can be implemented by logically programming method steps such that the controller is in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Such a controller may thus be considered a hardware component, and the means included therein for performing the various functions may also be considered as a structure within the hardware component. Or even means for performing the functions may be regarded as being both a software module for performing the method and a structure within a hardware component.
The apparatuses and modules illustrated in the above embodiments may be implemented by a computer chip or an entity, or by a product with certain functions.
For convenience of description, the above devices are described as being divided into various modules by functions, and are described separately. Of course, the functionality of the various modules may be implemented in the same one or more software and/or hardware implementations as the present application.
From the above description of the embodiments, it is clear to those skilled in the art that the present application can be implemented by software plus necessary general hardware platform. With this understanding in mind, the present solution, or portions thereof that contribute to the prior art, may be embodied in the form of a software product, which in a typical configuration includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory. The computer software product may include instructions for causing a computing device (which may be a personal computer, a server, or a network device, etc.) to perform the methods described in the various embodiments or portions of embodiments of the present application. The computer software product may be stored in a memory, which may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium. Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, 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 disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include transitory computer readable media (transient media), such as modulated data signals and carrier waves.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, as for the apparatus embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The application is operational with numerous general purpose or special purpose computing system environments or configurations. For example: personal computers, server computers, hand-held or portable devices, tablet-type devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.
The application may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The application may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.
While the present application has been described with examples, those of ordinary skill in the art will appreciate that there are numerous variations and permutations of the present application without departing from the spirit of the application, and it is intended that the appended claims encompass such variations and permutations without departing from the spirit of the application.

Claims (10)

1. A method of determining far field wavelets for an airgun array, the method providing an initial near field wavelet excited by an airgun source in the airgun array and recorded at a receiving point of a near field detector in a near field detector bank; the method comprises the following steps:
determining a filter factor according to the distance between the air gun seismic source and a near-field detector in the near-field detector group and the distance between a virtual image of the air gun seismic source and the near-field detector in the near-field detector group;
filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet;
determining a far-field wavelet corresponding to the air gun array according to the target near-field wavelet;
wherein, the filtering processing is carried out on the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet, and the method comprises the following steps:
obtaining a target near-field wavelet spectrum matrix for characterizing the initial near-field wavelet set of the filtered frequency domain using the following formula:
X(ω)＝(ATA+λI)-1ATB
wherein X (ω) represents the target near-field wavelet spectral matrix, ω represents angular frequency, A represents the filter factor, A representsTDenotes the transposed matrix of a and λ denotes the stability factor.
2. The method of claim 1, wherein said filtering said initial near-field wavelet with said filter factor to obtain a target near-field wavelet comprises:
converting the initial near-field wavelet from a time domain to a frequency domain to obtain an initial near-field wavelet of the frequency domain, and establishing an initial near-field wavelet spectrum matrix according to the initial near-field wavelet of the frequency domain; the initial near-field wavelet spectrum matrix is used for representing an initial near-field wavelet set of a frequency domain recorded by the near-field detector group correspondingly;
and filtering the initial near-field wavelet set represented by the initial near-field wavelet spectrum matrix by using the filtering factor to obtain a filtered initial near-field wavelet set of the frequency domain, and taking the filtered initial near-field wavelet set of the frequency domain as the target near-field wavelet.
3. The method of claim 2, wherein the filter factor is determined using the following equation:
wherein A represents the filter factor, rmnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the nth air gun seismic source in the air gun array, (r)g)mnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the virtual image of the nth air gun seismic source in the air gun array, C representing the speed of sound waves in water, i representing an imaginary number, i2-1; determining the initial near-field wavelet spectrum matrix using the following formula:
Figure FDA0002230980800000021
wherein N ism(ω) represents an initial near-field wavelet of a frequency domain recorded at a receiving point of an mth near-field detector in the near-field detector group, and m represents the number of near-field detectors in the near-field detector group.
4. The method of claim 3, wherein the stability factor has a value of 10-8。
5. The method of claim 3, wherein the far-field wavelet corresponding to the airgun array is determined using the following equation:
Figure FDA0002230980800000022
Figure FDA0002230980800000023
wherein the content of the first and second substances,
Figure FDA0002230980800000024
representing that the far-field wavelet corresponding to the air gun array has a propagation distance of R, a vertical azimuth angle of theta and a horizontal azimuth angle of theta
Figure FDA0002230980800000025
And far-field wavelets with angular frequency omega, wherein the vertical azimuth angle theta represents an included angle between the propagation direction of the far-field wavelets in a Cartesian coordinate system and the z-axis of the Cartesian coordinate system, and the horizontal azimuth angle is
Figure FDA0002230980800000026
Representing the included angle between the projection of the far-field wavelet propagation direction in the plane xoy of the Cartesian coordinate system and the x axis in the Cartesian coordinate system; r isn(r) represents the distance between the detection point of the far-field wavelet and the nth air gun source in the air gun arrayg)nRepresenting a distance between a detection point of the far-field wavelet and a virtual image of an nth airgun source in the airgun array.
6. The method of claim 5, wherein the distance r between the detection point of the far-field wavelet and the kth air-gun source in the air-gun array is calculated using the following equationk：
Figure FDA0002230980800000027
Wherein x isk、ykAnd zkRespectively representing the detection point of the far-field wavelet and the coordinates of the kth air gun seismic source in the cartesian coordinate system in the directions of an x axis, a y axis and a z axis.
7. The method of claim 5, wherein the distance (r) between the detection point of the far-field wavelet and the virtual image of the kth air-gun source in the air-gun array is calculated using the following equationg)k：
Figure FDA0002230980800000031
Wherein x isk、ykAnd zkRespectively representing the detection point of the far-field wavelet and the coordinates of the kth air gun seismic source in the cartesian coordinate system in the directions of an x axis, a y axis and a z axis.
8. An apparatus for determining far field wavelets for an airgun array, said apparatus providing an initial near field wavelet excited by an airgun source in the airgun array and recorded at a receiving point of a near field detector in a near field detector bank; the device comprises: the device comprises a filtering factor determining module, a target near-field wavelet determining module and a far-field wavelet determining module; wherein the content of the first and second substances,
the filter factor determination module is used for determining a filter factor according to the distance between the air gun seismic source and a near-field detector in the near-field detector group and the distance between a virtual image of the air gun seismic source and the near-field detector in the near-field detector group;
the target near-field wavelet determining module is used for filtering the initial near-field wavelet by using the filtering factor to obtain a target near-field wavelet;
the far-field wavelet determining module is used for determining the far-field wavelet corresponding to the air gun array according to the target near-field wavelet;
the target near-field wavelet determining module is used for obtaining a target near-field wavelet spectrum matrix for representing the initial near-field wavelet set of the filtered frequency domain by adopting the following formula:
X(ω)＝(ATA+λI)-1ATB
wherein X (ω) represents the target near-field wavelet spectral matrix, ω represents angular frequency, A represents the filter factor, A representsTDenotes the transposed matrix of a and λ denotes the stability factor.
9. The apparatus of claim 8, wherein the target near-field wavelet determining module is configured to convert the initial near-field wavelet from a time domain to a frequency domain to obtain an initial near-field wavelet of the frequency domain, and establish an initial near-field wavelet spectrum matrix according to the initial near-field wavelet of the frequency domain, where the initial near-field wavelet spectrum matrix is used to represent an initial near-field wavelet set of the frequency domain recorded by the near-field detector set, and perform filtering processing on the initial near-field wavelet set represented by the initial near-field wavelet spectrum matrix by using the filtering factor to obtain a filtered initial near-field wavelet set of the frequency domain, and use the filtered initial near-field wavelet set of the frequency domain as the target near-field wavelet.
10. The apparatus of claim 9, wherein the filter factor determining module is configured to determine the filter factor using the following equation:
Figure FDA0002230980800000041
wherein A represents the filter factor, rmnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the nth air gun seismic source in the air gun array, (r)g)mnRepresenting the distance between the receiving point of the mth near-field detector in the near-field detector group and the virtual image of the nth air gun seismic source in the air gun array, C representing the speed of sound waves in water, i representing an imaginary number, i2-1; determining the initial near-field wavelet spectrum matrix using the following formula:
Figure FDA0002230980800000042
wherein N ism(ω) represents an initial near-field wavelet of a frequency domain recorded at a receiving point of an mth near-field detector in the near-field detector group, and m represents the number of near-field detectors in the near-field detector group.
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