CN116859462A - Method for suppressing noise of controllable vibration source by energy spectrum correlation method - Google Patents
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Abstract
The invention provides a method for suppressing the noise of a controllable vibration source by an energy spectrum correlation method, which comprises the following steps: step 1, dividing data into a trapezoid with multiple time zones for analysis and research; step 2, obtaining amplitude and phase spectrums by utilizing Fourier transformation; step 3, pressing abnormal amplitude scattering noise by adopting a correlation method; and step 4, judging whether the multi-time zone three-trapezoid division is reasonable or not, namely whether the noise and the signal part can be sufficiently distinguished or not. The method for suppressing the noise of the controllable vibration source by the energy spectrum correlation method avoids the phenomenon that the CMP gather data or shot gather data are clearly and abnormally limited after the noise of the noise trapezoid area is suppressed by the high-energy black triangle, can obviously recover and strengthen effective reflected waves under the shielding of the igneous rock mass, and has great significance for improving the quality of seismic imaging.
Description
Technical Field
The invention relates to the technical field of oilfield development, in particular to a method for suppressing controllable source noise by an energy spectrum correlation method.
Background
After the efficient acquisition method of the controllable seismic source (Crawford, 1960) is proposed, a plurality of new technologies for improving the acquisition efficiency and the acquisition data quality are developed in the later period successively. The most widely used sliding scanning technique is currently the most mature. Although the production efficiency of the controllable seismic source is far higher than that of a well cannon; the cost of well digging and explosive is saved, and the management cost of explosive is saved, so that the construction cost of the controllable seismic source is far lower than that of a well gun; however, due to the special field acquisition mode of the technique, adjacent scan intervals are subject to harmonic effects, which increase with decreasing sliding time. Meanwhile, because the harmonic interference is complex and changeable in the same detection area and the acquired data volume is large, the harmonic interference must be effectively suppressed in order to improve the operation efficiency and the data quality.
Along with the technical development, the method for processing the seismic noise of the controllable earthquake focus is increasingly diversified, such as F-K coherent noise elimination, channel combination noise elimination, high-precision radial channel scanning method, correlation method, PPSF (Pure Phase Shift Filter) method and deconvolution method, the method for improving coverage times and suppressing regular interference, acoustic wave denoising, optimizing dynamic scanning parameters and reducing channel set interference, harmonic interference suppression technology and model method, and provides an effective way for suppressing the seismic noise of the controllable earthquake focus.
Although there are many advantages of the controlled seismic source over the explosive seismic source, there are still many disadvantages in noise interference, bandwidth, phase, etc: the strong energy of the surface wave and the nonlinear strong interference noise generated by the excitation of the controllable vibration source are shown as strong development full-band noise on the gather, which is commonly called as 'black triangle'.
PPSF (Pure Phase Shift Filter) is to combine deterministic deconvolution, design a pure phase shift factor according to scan parameters, then use it to divide and time shift the seismic record before cross correlation, and then combine low-pass filtering to suppress the harmonics in the seismic record shifted to the negative time axis in a large range. The method has the defects that the method can only be used for suppressing the harmonic waves at strong energy signals such as first arrival or shallow reflection of the up-conversion scanning data, the application range is reduced due to up-conversion scanning, the residual is more due to the fact that the harmonic waves among different vibration signals cannot be completely suppressed, and the processing efficiency is low due to the fact that time-frequency domain processing is adopted in the implementation method.
The deconvolution method is to deconvolute the record before cross-correlation by utilizing the controllable seismic source signal actually transmitted into the ground, and has the advantages that the reflection coefficient sequence can be directly obtained; the disadvantage is that the signals transmitted into the subsurface are known, and if the data used is a splice of the source with other source types (such as explosives), the splice and subsequent processing is difficult because the source has been processed to obtain a sequence of reflection coefficients, and the data from other sources is still in the seismic wavelet phase.
The model rule is to design a harmonic predictor based on the source force signal, calculate the harmonic interference in the related record, and finally remove the calculated harmonic interference from the interfered area. However, in actual seismic data acquisition, the source force signals are not easily obtained due to equipment and the like, so that a model method cannot be applied to suppress harmonic waves.
The method comprises the steps of carrying out convolution on signals of different types, such as scanning signals, force signals, bottom plate signals and the like, and stratum reflection coefficient sequences to obtain a pre-correlation seismic record, and carrying out cross-correlation on the signals and the pre-correlation seismic record to obtain a post-correlation seismic trace. The method only has less high-frequency interference of the related post-seismic record channel when the scanning signal only containing the fundamental wave is used, and the high-frequency interference obtained when the actual signal is used is serious, so that the post-processing result is not ideal.
The article reduces noise interference of the controllable vibration source high-efficiency acquisition data, and the author; li Xuegang, publication: in the interior river science and technology, in 2014, 5 th period 46-47, a controllable focus noise is suppressed by adopting a suppression technology for improving coverage times to suppress regular interference, removing noise by sound waves and reducing intersection interference by optimizing dynamic scanning parameters; article "method for eliminating coherent noise of vibroseis data", author: ge Chuanqing et al, publication: jiang Han university of petroleum staff report, 2009,22 (4), in which three methods of F-K coherent noise cancellation, channel combination cancellation and high-precision radial channel scanning cancellation are mentioned for denoising, these filtering methods, due to the limitation of theory itself, do not make full use of the characteristic of strong energy of the "black triangle" region, inevitably produce some artificial artifacts or cancel the phenomenon of uncleanness or loss of effective waves.
By researching the formation mechanism of abnormal amplitude of the black triangle, the explosive source excites the elastic wave energy generated by explosion in the explosive source well below the diving surface to reduce the intensity of the surface wave. The controllable vibration source is excited on loose ground surface, a strong wave impedance interface is formed between a low-speed layer and a high-speed layer, the controllable vibration source is excited by continuous energy for a long time, and energy scanned at different moments oscillates back and forth in a low-speed band, so that harmonic distortion is easy to generate. The main reason is that the special surface layer structure of the desert terrain causes (a great amount of gas exists in the sand dune, the unsaturated moisture density is uneven, and scattering is easy to form). Harmonic distortion mainly develops in a near shot triangle area, presents abnormal 'black triangle' amplitude noise, and presents strong full-band nonlinear scattering noise on a gather. The noise interference of the 'black triangle' area in the controllable vibration source noise development area is serious, so that the imaging quality of a target layer is influenced, and therefore, the recognition and suppression of the 'black triangle' area noise are key problems of research. It appears necessary to distinguish and suppress the strong energy noise.
In application number: in the chinese patent application CN201810802534.4, a method for suppressing noise in black triangle of seismic data excited by a controllable seismic source is related to the method, wherein all data in any set are divided into data in black triangle and data outside black triangle, the data in black triangle is mainly noise, the data outside black triangle is mainly signal, and the correlation coefficient of the two reflects the correlation degree of noise and signal. Noise in the black triangle is mainly used for destroying the amplitude of a signal, the influence of the noise on the phase of the signal is small, the amplitude spectrum of the data in the black triangle is suppressed by utilizing the cross-correlation coefficient of the data in the black triangle and the data outside the black triangle, the characteristic of strong energy of the black triangle is fully considered, and the noise is eliminated, and the loss of effective waves is greatly reduced. The method does not distinguish how to identify and how to partition specific noise with respect to 'black triangle' noise. Whether the energy boundary is processed or not easily causes the problem of energy boundary distortion after noise suppression, and in addition, from the effect, a certain amount of noise still remains in an overlapping area of a black triangle area and an effective signal area.
In application number: in chinese patent application No. cn201910817079.X, a ground microseism noise suppression method is related, comprising: performing time difference correction on the input microseism data to obtain correction data; randomly disturbing the sequence of the correction data to obtain data to be processed; performing time window division and frequency band division on the data to be processed to obtain division data; carrying out noise attenuation treatment on the divided data according to a threshold value to obtain noise attenuated data; and recovering the sequence of the data after noise attenuation based on the random scrambling mode to obtain final microseism data. The ground microseism noise suppression method provided by the embodiment of the invention has the advantages of multiple attenuation noise types, stronger applicability and remarkable noise attenuation effect.
In application number: in the chinese patent application CN201510278789.1, a method for suppressing the harmonic of a controllable seismic source based on a predictive filtering method and a pure phase shift method is related, and the method for suppressing the harmonic of the controllable seismic source based on the predictive filtering method and the pure phase shift method includes: step 1, inputting a cross-correlation seismic record and a corresponding ground force signal after pure phase shift processing; step 2, suppressing the harmonic interference of the gun by using a pure phase shift method; step 3, suppressing the adjacent gun harmonic interference by using a prediction filtering method: and 4, obtaining the whole continuous controllable seismic source scanning data after suppressing harmonic interference. The method for suppressing the controllable focus harmonic wave based on the prediction filtering method and the pure phase shift method provides a method for suppressing the harmonic wave of mass seismic data of the controllable focus, which can suppress the adjacent gun interference noise well and can partially eliminate the gun internal harmonic wave interference.
The prior art is greatly different from the invention, the technical problem which is needed to be solved by the invention is not solved, and a novel energy spectrum correlation method controlled source noise suppression method is invented for the purpose.
Disclosure of Invention
The invention aims to provide a method for suppressing the noise of a controllable vibration source by an energy spectrum correlation method, which can recover the effective wave signal of a region and suppress the black triangle of the controllable vibration source.
The aim of the invention can be achieved by the following technical measures: the method for suppressing the noise of the controllable vibration source by the energy spectrum correlation method comprises the following steps of:
step 1, dividing data into a trapezoid with multiple time zones for analysis and research;
step 2, obtaining amplitude and phase spectrums by utilizing Fourier transformation;
step 3, pressing abnormal amplitude scattering noise by adopting a correlation method;
and step 4, judging whether the multi-time zone three-trapezoid division is reasonable or not, namely whether the noise and the signal part can be sufficiently distinguished or not.
The aim of the invention can be achieved by the following technical measures:
in the step 1, SHOT set SHOT or common center point gather CMP data of the vibroseis noise still remained after the surface pressing is divided into a plurality of trapezoid parts; equally dividing a plurality of time zones from top to bottom in the time direction; dividing each time zone into three trapezoids, wherein the noise trapezoids are positioned on two sides of the signal trapezoids; such a data is divided into a plurality of time zones, each of which has three data portions of three trapezoids, namely, a noise trapezoid region, a signal trapezoid region and all data.
In step 2, amplitude and phase spectra are obtained by fourier transform; and respectively carrying out Fourier FFT positive transformation on the three data aiming at the noise trapezoidal region, the signal trapezoidal region and all the data to obtain three energy spectrums and three phase spectrums.
In step 2, for the signal trapezoidal region, the data energy spectrum and the phase spectrum are:
P s (ω)＝arctan(I s (ω)/R s (ω)) (2)
the formula (1) and the formula (2) are respectively the data energy spectrum and the phase spectrum of the trapezoidal region of the signal. I A s (ω) i is the signal trapezoidal section data energy spectrum; r is R s (ω) is the real part of the data energy spectrum of the trapezoidal region of the signal after the fourier positive transform; i s (ω) is the imaginary part of the data energy spectrum of the signal trapezoidal section after the fourier positive transform; p (P) s And (omega) is the data phase spectrum of the trapezoidal region of the signal.
In step 2, for the noise trapezoidal region, the data energy spectrum and the phase spectrum are:
P n (ω)＝arctan(I n (ω)/R n (ω)) (4)
the formula (3) and the formula (4) are respectively a noise trapezoid data energy spectrum and a phase spectrum. I A n (ω) is the noise trapezoidal section data energy spectrum; r is R n (ω) is the real part of the data energy spectrum of the noise trapezoidal region after the fourier positive transform; i n (ω) is the imaginary part of the data energy spectrum of the noise trapezoidal region after the fourier positive transform; p (P) n And (omega) is the data phase spectrum of the noise trapezoidal region.
In step 2, for all data, the data energy spectrum and the phase spectrum are:
P a (ω)＝arctan(I a (ω)/R a (ω)) (6)
the formula (5) and the formula (6) are all data (signal+noise)) Energy spectrum and phase spectrum; i A a (ω) is the overall data energy spectrum; r is R a (ω) is the real part of the energy spectrum of the whole trapezoidal region data after fourier positive transformation; i a (omega) is the imaginary part of the energy spectrum of the data of the whole trapezoid area after Fourier positive transformation; p (P) a And (omega) is the data phase spectrum of the whole trapezoid area.
In the step 3, the noise trapezoid area mainly has destroyed signal amplitude, but the signal phase is less affected, the data in the noise trapezoid is reserved with the phase spectrum, and the amplitude is suppressed; the correlation degree is obtained on the energy spectrums of the three trapezoidal data, and the correlation similarity is too high, so that the noise trapezoidal amplitude is not easy to distinguish and suppress.
In step 3, the energy spectrum frequency direction derivatives of the three data are calculated:
C sa (m)＝∑A sd (ω)*A ad (ω+m) (10)
C na (m)＝∑A nd (ω)*A ad (ω+m) (11)
C ns (m)＝∑A nd (ω)*A sd (ω+m) (12)
(7) The formulas (8) and (9) are three data derivative formulas; a is that sd (ω) is the data energy spectrum derivative of the signal trapezoidal section; a is that nd (ω) is the energy spectrum derivative of the noise trapezoidal region; a is that ad (ω) is the total data energy spectrum derivative.
(10) Equations (11) and (12) are respectively the formulas of the mutual correlation of the three groups of energy spectrum derivatives. C (C) sa (m) the derivative and the whole of the energy spectrum of the data in the trapezoidal region of the signalPerforming cross correlation on the data energy spectrum derivative; c (C) na (m) cross-correlating the energy spectrum derivative of the noise trapezoidal region with the energy spectrum derivative of all the data; c (C) ns (m) cross-correlating the energy spectrum derivative of the noise trapezoidal region with the energy spectrum derivative of the data trapezoidal region.
In the step 3, the correlation degree between all data and a signal trapezoidal area is highest; and the correlation degree between the noise trapezoid area and all data is inferior; the correlation degree between the noise trapezoid area and the signal trapezoid area is the lowest; the amplitudes of different channels of the signal trapezoidal data are utilized to carry out data weighting on the amplitudes of the data in the noise trapezoidal data in different frequency segments so as to match the amplitudes of the data in the signal trapezoidal region, and the amplitudes of the noise trapezoidal region are basically consistent with the amplitudes of the signal trapezoidal region; then, data information of different frequency segments is overlapped to complete normalization; and after the amplitude matching is completed, combining the energy spectrum and the phase spectrum to perform Fourier inverse transformation, so as to obtain pressed single shot or common center point gather data.
In step 4, outputting a calculation and analysis result of a pressed single shot or common center point gather for a user to perform effect inspection QC, and inspecting whether the area division is reasonable or not according to actual data conditions; in addition, it is checked whether the fourier transform is normal.
The data needs to be divided into a number of areas from top to bottom, the parameter being the time direction, the size of the window, i.e. the number of window points. This parameter is very important, too little to consume much computer time, and too much data amplitude remains lost. The sampling rate according to the input data can be flexibly selected. The size of the trapezoid is adjusted by using the linear surface wave velocity. The greater the speed, the greater the "noise trapezium" chosen, and vice versa. The large division of the noise trapezoid area easily causes the small signal trapezoid area, and causes the loss of effective signals. The trapezoid area of noise is too small, and the "black triangle noise" is not completely pressed. In the actual operation process, the technicians need to test in detail.
Compared with the prior art, the method for pressing the noise of the controllable vibration source by using the energy spectrum correlation method has the following main advantages:
(1) Aiming at SHOT Set (SHOT) or common center point gather (CMP) data of residual 'black triangle' noise, different trapezoid division and time window division of multiple time zones can be adjusted according to different development degrees of 'black triangle' noise in different areas, and the size parameters can be adjusted to achieve the optimal pressing effect; the amplitude of the noise area is subjected to data edging soft processing after pressing, so that the phenomenon that the data limit of the CMP gather is clearly deformed after the noise area is pressed due to the high-energy black triangle is avoided.
(2) Compared with the traditional denoising method, which can not thoroughly press the 'black triangle' noise and hurt the effective signal, the method is advanced in theory, flexible and convenient to apply, has very ideal application effect in the denoising process of the actual trace set of the Tarim blocks, can obviously recover and strengthen the effective reflected wave under the shielding of the igneous rock mass, and has great significance for improving the seismic imaging quality.
Drawings
FIG. 1 is a schematic diagram of an original single shot in an embodiment of the present invention;
FIG. 2 is a graph illustrating the correlation analysis of energy spectrum according to an embodiment of the present invention;
FIG. 3 is a graph showing the comparison of the energy spectrum correlation method noise suppression before and after the common center point trace (CMP) in accordance with one embodiment of the present invention;
FIG. 4 is a cross-sectional view of the energy spectrum correlation method noise suppression before and after superposition in accordance with an embodiment of the present invention;
FIG. 5 is a graph showing a comparison of single shots before and after noise suppression by an energy spectrum correlation method according to another embodiment of the present invention;
FIG. 6 is a cross-sectional view of the energy spectrum correlation method noise suppression before and after superposition in another embodiment of the invention;
FIG. 7 is a graph comparing the trace of the common center point before and after noise suppression by the energy spectrum correlation method according to another embodiment of the present invention;
FIG. 8 is a flow chart of a method for vibroseis noise suppression using the energy spectrum correlation method of the present invention.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular forms also are intended to include the plural forms unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, and/or combinations thereof.
According to the method for pressing the noise of the controllable vibration source by using the energy spectrum correlation method, the data of the noise of the controllable vibration source still remained after the surface pressing is divided into a trapezoid with multiple time zones; and carrying out Fourier transform on trapezoid data of different multi-time areas of noise in the black triangle area to obtain different energy spectrums, and suppressing abnormal amplitude scattered noise by using an energy spectrum correlation method to recover the effective signal amplitude in the black triangle area. The method for suppressing the controllable source noise by the energy spectrum correlation method mainly comprises the following steps of:
(1) The data is divided into three trapezoids of a multi-time zone;
(2) Spectral correlation method rationale;
(3) Suppressing abnormal amplitude scattering noise by a spectrum correlation method;
(4) QC monitoring and recovering signals;
the following are several specific examples of the application of the present invention.
Example 1
In a specific embodiment 1 to which the present invention is applied, as shown in fig. 5, fig. 5 is a flowchart of a method for suppressing vibroseis noise by using the energy spectrum correlation method of the present invention. The method for suppressing the controllable source noise by using the energy spectrum correlation method comprises the following steps of:
step 101, dividing the data into analysis and research of trapezoids in multiple time zones; CMP data, which still has vibroseis noise after pressing the face, is divided into multiple trapezoidal sections, as shown in FIG. 1: equally dividing a plurality of time zones from top to bottom in the time direction; each time zone is subdivided into three noise trapezoids, i.e. irregular abnormal amplitude zones, signal trapezoids (signal zones). Such a CMP has a plurality of time zones, each time zone having three data portions of three trapezoids, namely a "noise trapezoids" region, a "signal trapezoids" region and all data.
102, obtaining amplitude and phase spectrums by utilizing Fourier transformation; and respectively carrying out FFT positive conversion on three data of different partitions of the multi-region trapezoid to obtain three energy spectrums and three phase spectrums.
And carrying out FFT positive conversion on the three data respectively to obtain three energy spectrums and three phase spectrums in the noise trapezoid area, the signal trapezoid area and all data. They are respectively:
P s (ω)＝arctan(I s (ω)/R s (ω)) (2)
the formula (1) and the formula (2) are respectively a data energy spectrum and a phase spectrum of a signal trapezoid area;
P n (ω)＝arctan(I n (ω)/R n (ω)) (4)
the formula (3) and the formula (4) are respectively a noise trapezoid data energy spectrum and a phase spectrum;
P a (ω)＝arctan(I a (ω)/R a (ω)) (6)
the formula (5) and the formula (6) are the energy spectrum and the phase spectrum of all data (signal+noise);
step 103, researching an abnormal amplitude scattering noise suppression method by a correlation method; the "noise trapezoid" region is mainly where the signal amplitude is corrupted, but the signal phase is less affected. We hold the data in the "noise trapezoids" to preserve its phase spectrum, suppressing the amplitude. The correlation degree is obtained on the energy spectrums of the three trapezoidal data, and the mutual correlation similarity is too high, so that the method is not beneficial to distinguishing and suppressing the amplitude of the noise trapezoids. And then the derivative of the energy spectrum frequency direction of the three data is obtained,
C sa (m)＝∑A sd (ω)*A ad (ω+m) (10)
C na (m)＝∑A nd (ω)*A ad (ω+m) (11)
C ns (m)＝∑A nd (ω)*A sd (ω+m) (12)
(7) The formulas (8) and (9) are three data derivative formulas; (10) Equations (11) and (12) are respectively the formulas of the mutual correlation of three groups of energy spectrum derivatives; the correlation degree between all data and a signal trapezoid area is highest; and the correlation between the noise trapezoid area and the whole data is inferior; the "noise trapezoid" region has the lowest correlation with the "signal trapezoid" region, as shown in fig. 2. Fig. 2 shows the correlation between all data and the "signal trapezoid" region, and the correlation between the "noise trapezoid" region and all data. The amplitudes of different channels of the noise trapezium are overlapped and normalized at different frequencies by utilizing the amplitude of different channels of the noise trapezium, namely the signal trapezium, and the amplitude and the phase spectrum of the data in the noise trapezium are multiplied by a coefficient at different frequencies. The Fourier transform (FFT) is carried out to form an energy spectrum and a phase spectrum, and the Fourier transform (FFT) is carried out by combining the energy spectrum and the phase spectrum to obtain the original data. If only the energy spectrum or the phase spectrum is used, it is difficult to obtain the original data, but the phase spectrum is more similar to the original data than the energy spectrum.
Step 104, judging whether the multi-time zone three-trapezoid division is reasonable, namely whether the noise and the signal part can be sufficiently distinguished. Meanwhile, the software outputs a calculation and analysis result of a common center point gather (CMP) for the user to perform QC. Through the analysis, whether the division of the three trapezoid areas in multiple time zones is reasonable or not, namely whether noise and signal parts can be sufficiently distinguished or not can be recognized.
The data needs to be divided into a number of areas from top to bottom, the parameter being the time direction, the size of the window, i.e. the number of window points. This parameter is very important, too little to consume much computer time, and too much data amplitude remains lost. The sampling rate according to the input data can be flexibly selected. The size of the trapezoid is adjusted by using the linear surface wave velocity. The greater the speed, the greater the "noise trapezium" chosen, and vice versa. The large division of the noise trapezoid area easily causes the small signal trapezoid area, and causes the loss of effective signals. The trapezoid area of noise is too small, and the "black triangle noise" is not completely pressed. In the actual operation process, the technicians need to test in detail.
Example 2
In a specific embodiment 2 to which the present invention is applied, the noise within the noise ladder is dominant and the signal is masked. In general, mainly the signal amplitude is destroyed, but the signal phase is less affected. The data in the noise trapezium is subjected to Fourier transformation, the phase spectrum of the data is reserved, and the amplitude is suppressed. The effective signal recovery is realized by using the technology of the technology for suppressing the noise of the controllable vibration source by using the actual earthquake data and adopting an energy spectrum correlation method to suppress the strong energy noise of the controllable vibration source data (figures 3 and 4).
The invention uses the characteristic of controllable source noise, adopts FFT conversion, energy spectrum correlation method and inverse conversion to identify and suppress the strong energy noise in the 'black triangle' area, and recovers the effective wave signal in the area, and can also be realized by other mathematical algorithms.
Example 3:
in a specific embodiment 3 of the present invention, the noise in the shot gather is the main noise in the trapezoid, and the signal is masked. In general, mainly the signal amplitude is destroyed, but the signal phase is less affected. The data in the noise trapezium is subjected to Fourier transformation, the phase spectrum of the data is reserved, and the amplitude is suppressed. The method is characterized in that the technology for suppressing the noise of the controllable seismic source by using the energy spectrum correlation method is adopted to suppress the strong energy noise of the controllable seismic source data through actual seismic data, and the selection 300 of the noise range parameters of the black triangle is adopted in the example. Effective signal recovery is achieved (fig. 5, 6).
Example 4:
in an embodiment 4 of the present invention, noise in the common-center-point gather (CMP) is dominant in noise in the trapezoid, and shallow first-arrival refraction interference is severe. The technology for suppressing the noise of the controllable vibration source by adopting the energy spectrum correlation method is used for suppressing the data strong energy noise of the controllable vibration source, the parameter of the noise range of the black triangle in the example is selected to be 500, and the output mode is selected to be the first arrival and refraction interference. Effective signal recovery is achieved (fig. 7).
The invention relates to an energy spectrum correlation method controllable seismic source noise suppression method, which divides residual black triangle into trapezoids with multiple time zones for energy spectrum correlation analysis by noise datamation and utilizes the difference of correlation between signals and noise amplitude in a frequency domain: the noise trapezium and the signal trapezium have poor correlation, so that the suppression of the scattered noise with abnormal amplitude can be identified; and then combining the amplitude spectrum and the phase spectrum to perform FFT inverse transformation to obtain data after suppressing the 'black triangle' noise, and recovering effective signals.
Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but although the present invention has been described in detail with reference to the foregoing embodiment, it will be apparent to those skilled in the art that modifications may be made to the technical solution described in the foregoing embodiment, or equivalents may be substituted for some of the technical features thereof. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Other than the technical features described in the specification, all are known to those skilled in the art.
Claims (10)
1. The method for suppressing the noise of the controllable vibration source by the energy spectrum correlation method is characterized by comprising the following steps of:
step 1, dividing data into a trapezoid with multiple time zones for analysis and research;
step 2, obtaining amplitude and phase spectrums by utilizing Fourier transformation;
step 3, pressing abnormal amplitude scattering noise by adopting a correlation method;
and step 4, judging whether the multi-time zone three-trapezoid division is reasonable or not, namely whether the noise and the signal part can be sufficiently distinguished or not.
2. The method for suppressing vibroseis noise by energy spectrum correlation as recited in claim 1, wherein in step 1, SHOT set SHOT or common center point gather CMP data of vibroseis noise remaining after the pressing of the surface is divided into a plurality of trapezoid parts; equally dividing a plurality of time zones from top to bottom in the time direction; dividing each time zone into three trapezoids, wherein the noise trapezoids are positioned on two sides of the signal trapezoids; such a data is divided into a plurality of time zones, each of which has three data portions of three trapezoids, namely, a noise trapezoid region, a signal trapezoid region and all data.
3. The method for vibroseis noise suppression by energy spectrum correlation according to claim 1, characterized in that in step 2, amplitude and phase spectra are obtained by fourier transform; and respectively carrying out Fourier positive transformation on the three data aiming at the noise trapezoidal region, the signal trapezoidal region and all the data to obtain three energy spectrums and three phase spectrums.
4. The method for suppressing noise of a vibroseis by using an energy spectrum correlation method according to claim 3, wherein in step 2, for a signal trapezoidal region, the data energy spectrum and the phase spectrum are as follows:
P s (ω)＝arctan(I s (ω)/R s (ω)) (2)
the formula (1) and the formula (2) are respectively the data energy spectrum and the phase spectrum of the trapezoidal region of the signal; i A s (ω) i is the signal trapezoidal section data energy spectrum; r is R s (ω) is the real part of the data energy spectrum of the trapezoidal region of the signal after the fourier positive transform; i s (ω) is the imaginary part of the data energy spectrum of the signal trapezoidal section after the fourier positive transform; p (P) s And (omega) is the data phase spectrum of the trapezoidal region of the signal.
5. The method for vibroseis noise suppression according to claim 4, wherein in step 2, for the noise trapezoidal region, the data energy spectrum and the phase spectrum are:
P n (ω)＝arctan(I n (ω)/R n (ω)) (4)
the formula (3) and the formula (4) are respectively noise trapezoid data energy spectrum and phase spectrum; i A n (ω) is the noise trapezoidal section data energy spectrum; r is R n (ω) is the real part of the data energy spectrum of the noise trapezoidal region after the fourier positive transform; i n (ω) is the imaginary part of the data energy spectrum of the noise trapezoidal region after the fourier positive transform; p (P) n And (omega) is the data phase spectrum of the noise trapezoidal region.
6. The method for vibroseis noise suppression according to claim 5, wherein in step 2, for all data, the data energy spectrum and the phase spectrum are:
P a (ω)＝arctan(I a (ω)/R a (ω)) (6)
the formula (5) and the formula (6) are all data energy spectrums and phase spectrums respectively; i A a (ω) is the overall data energy spectrum; r is R a (ω) is the real part of the energy spectrum of the total data after fourier positive transformation; i a (ω) is the imaginary part of the total data energy spectrum after the fourier positive transform; p (P) a (ω) is the overall data phase spectrum.
7. The method of claim 6, wherein in step 3, the noise ladder region is mainly where the signal amplitude is destroyed, but the signal phase is less affected, the data in the noise ladder is kept with its phase spectrum, and the amplitude is suppressed; the correlation degree is obtained on the energy spectrums of the three trapezoidal data, and the correlation similarity is too high, so that the noise trapezoidal amplitude is not easy to distinguish and suppress.
8. The method of energy spectrum correlation vibroseis noise suppression according to claim 7, wherein in step 3, the energy spectrum frequency direction derivatives of the three data are obtained:
C sa (m)＝∑A sd (ω)*A ad (ω+m) (10)
C na (m)＝∑A nd (ω)*A ad (ω+m) (11)
C ns (m)＝∑A nd (ω)*A sd (ω+m) (12)
(7) The formulas (8) and (9) are three data derivative formulas; a is that sd (ω) is the data energy spectrum derivative of the signal trapezoidal section; a is that nd (ω) is the data energy spectrum derivative of the noisy trapezoidal region; a is that ad (ω) is the total data energy spectrum derivative;
(10) Equations (11) and (12) are respectively the formulas of the mutual correlation of three groups of energy spectrum derivatives; c (C) sa (m) cross-correlating the data energy spectrum derivatives of the trapezoidal region of the signal with the energy spectrum derivatives of all the data; c (C) na (m) cross-correlating the data energy spectrum derivatives for the noise trapezoidal region with the total data energy spectrum derivatives; c (C) ns (m) cross-correlating the data energy spectrum derivative in the noise trapezoidal region with the data energy spectrum derivative in the signal trapezoidal region.
9. The method for suppressing noise of a vibroseis by using an energy spectrum correlation method according to claim 8, wherein in the step 3, the correlation degree between all data and a signal trapezoidal region is the highest; and the correlation degree between the noise trapezoid area and all data is inferior; the correlation degree between the noise trapezoid area and the signal trapezoid area is the lowest; the amplitudes of different channels of the signal trapezoidal data are utilized to carry out data weighting on the amplitudes of the data in the noise trapezoidal data in different frequency segments so as to match the amplitudes of the data in the signal trapezoidal region, and the amplitudes of the noise trapezoidal region are basically consistent with the amplitudes of the signal trapezoidal region; then, data information of different frequency segments is overlapped to complete normalization; and after the amplitude matching is completed, combining the energy spectrum and the phase spectrum to perform Fourier inverse transformation, so as to obtain pressed single shot or common center point gather data.
10. The method for suppressing noise of a controllable vibration source according to claim 1, wherein in step 4, a result of calculation and analysis of a pressed single shot or common center point gather is outputted for a user to perform effect inspection QC, and the user inspects whether the area division is reasonable according to the actual data situation; in addition, it is checked whether the fourier transform is normal.
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