阅读说明：本技术 有效地震信号的提取方法、装置、设备和存储介质 (Method, device, equipment and storage medium for extracting effective seismic signals ) 是由 高少武 张少华 于 2020-05-18 设计创作，主要内容包括：本公开是关于一种有效地震信号的提取方法、装置、设备和存储介质,属于地震处理技术领域。该方法包括获取地震数据；对获取的地震数据进行噪声压制处理,得到预测地震信号和预测噪声干扰信号；获取预测地震信号的第一自相关函数、预测噪声干扰信号的第二自相关函数以及预测地震信号和预测噪声干扰信号的互相关函数；基于第一自相关函数、第二自相关函数以及互相关函数,确定有效地震信号的能量系数特征方程；基于有效地震信号的能量系数特征方程,确定有效地震信号的最佳有效地震信号能量系数；基于最佳有效信号能量系数和预测地震信号确定有效地震信号。(The disclosure relates to a method, a device, equipment and a storage medium for extracting effective seismic signals, and belongs to the technical field of seismic processing. The method includes acquiring seismic data; carrying out noise suppression processing on the acquired seismic data to obtain a predicted seismic signal and a predicted noise interference signal; acquiring a first autocorrelation function of a predicted seismic signal, a second autocorrelation function of a predicted noise interference signal and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal; determining an energy coefficient characteristic equation of the effective seismic signal based on the first autocorrelation function, the second autocorrelation function and the cross-correlation function; determining the optimal effective seismic signal energy coefficient of the effective seismic signals based on the energy coefficient characteristic equation of the effective seismic signals; an effective seismic signal is determined based on the optimal effective signal energy coefficient and the predicted seismic signal.)

1. A method of extracting significant seismic signals, the method comprising:

acquiring seismic data;

carrying out noise suppression processing on the acquired seismic data to obtain a predicted seismic signal and a predicted noise interference signal;

obtaining a first autocorrelation function of the predicted seismic signal, a second autocorrelation function of the predicted noise interference signal, and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal;

determining an energy coefficient characteristic equation of the effective seismic signal based on the first autocorrelation function, the second autocorrelation function and the cross-correlation function, wherein the energy coefficient characteristic equation of the effective seismic signal is used for expressing an equation of a relation between an energy coefficient of the effective seismic signal and a characteristic factor, and the characteristic factor expresses a relation among the first autocorrelation function, the second autocorrelation function and the cross-correlation function;

determining an optimal effective seismic signal energy coefficient of the effective seismic signals based on the energy coefficient characteristic equation of the effective seismic signals, wherein the optimal effective seismic signal energy coefficient of the effective seismic signals is the energy coefficient of the effective seismic signals when the energy value of the second autocorrelation function is minimum;

determining the effective seismic signal based on the optimal effective signal energy coefficient and the predicted seismic signal.

2. The method of extracting significant seismic signals of claim 1, wherein the second autocorrelation function is:

the first autocorrelation function is:

the cross-correlation function is:

wherein N is_iRepresenting the predicted noise interference signal at time i, N_i+kRepresenting the predicted noise interference signal at time i + k, S_iRepresenting the predicted seismic signal at time i, S_i+kRepresenting the predicted seismic signal at time i + k;

k represents the sequence number of the delayed sampling points of the autocorrelation function, k is 0,1,2, …, and L is an integer;

i represents the time sample sequence number, i is 1,2, …, M represents the total number of time samples, M is a positive integer, and L is less than or equal to M.

3. The method of claim 2, wherein determining an energy coefficient signature equation for the significant seismic signal based on the first autocorrelation function, the second autocorrelation function, and the cross-correlation function comprises:

the following formula is adopted as an energy coefficient characteristic equation of the effective seismic signals:

wherein the content of the first and second substances,

α denotes the energy coefficient of the effective seismic signal, f₁、f₂、f₃、f₄And f₅Respectively, representing the characteristic factors.

4. The method of extracting significant seismic signals of any of claims 1 to 3, wherein determining an optimal significant seismic signal energy coefficient for a significant seismic signal based on an energy coefficient signature equation for the significant seismic signal comprises:

determining a cubic characteristic equation based on an energy coefficient characteristic equation of the effective seismic signal;

determining a characteristic root of the cubic characteristic equation;

if the cubic characteristic equation has one characteristic root, determining an optimal effective seismic signal energy coefficient based on the one characteristic root;

if the cubic characteristic equation has a plurality of characteristic roots, determining a plurality of effective signal energy coefficients based on the plurality of characteristic roots; respectively determining corresponding second autocorrelation function energy values based on the plurality of effective signal energy coefficients; and comparing the determined energy values of the second autocorrelation function, and taking the effective seismic signal energy coefficient corresponding to the minimum energy value of the second autocorrelation function as the optimal effective seismic signal energy coefficient.

5. The method of extracting significant seismic signals of claim 4, wherein determining a cubic characteristic equation based on an energy coefficient characteristic equation for the significant seismic signals comprises:

determining a cubic characteristic equation based on an effective signal energy coefficient expression and an energy coefficient characteristic equation of the effective seismic signal;

wherein the effective signal energy coefficient expression is:

the cubic characteristic equation is as follows:

γ³+g₁γ+g₂＝0；

wherein:

the three characteristic roots of the cubic characteristic equation are respectively:

wherein:

ω denotes an imaginary constant factor, l denotes an imaginary unit, l²＝-1。

6. The method of claim 5, wherein determining the corresponding second autocorrelation function energy values based on the plurality of significant signal energy coefficients comprises:

calculating a second autocorrelation function energy value based on the following formula:

Q₁、Q₂and Q₃Representing the energy value of the second autocorrelation function, α₁、α₂And α₃Representing the effective signal energy coefficient.

7. The method of extracting significant seismic signals of any of claims 1 to 3, wherein determining significant seismic signals based on the optimal significant signal energy coefficient and the predicted seismic signals comprises:

determining a valid seismic signal based on the formula:

wherein β_best＝1+α_best；

Representing the effective seismic signal, S_iRepresenting predicted seismic signals, α_bestRepresenting the best effective signal energy coefficient.

8. An apparatus for extracting a significant seismic signal, the apparatus comprising:

a first acquisition module configured to acquire seismic data;

the processing module is configured to perform noise suppression processing on the acquired seismic data to obtain a predicted seismic signal and a predicted noise interference signal;

a second acquisition module configured to acquire a first autocorrelation function of the predicted seismic signal, a second autocorrelation function of the predicted noise interference signal, and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal;

a first determination module configured to determine an energy coefficient characteristic equation of the effective seismic signal based on the first autocorrelation function, the second autocorrelation function and the cross-correlation function, the energy coefficient characteristic equation of the effective seismic signal being an equation representing a relationship between an energy coefficient of the effective seismic signal and a characteristic factor representing a relationship between the first autocorrelation function, the second autocorrelation function and the cross-correlation function;

a second determination module configured to determine an optimal effective seismic signal energy coefficient for the effective seismic signal based on an energy coefficient characteristic equation for the effective seismic signal, the optimal effective seismic signal energy coefficient for the effective seismic signal being an energy coefficient for the effective seismic signal at which a second autocorrelation function energy value is minimum;

a third determination module configured to determine a valid seismic signal based on the optimal valid signal energy coefficient and the predicted seismic signal.

9. A computer device, characterized in that the computer device comprises:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to perform the method of extracting significant seismic signals of any of claims 1 to 7.

10. A storage medium having stored therein a computer program for execution by a processor to implement the method of extracting effective seismic signals according to any one of claims 1 to 7.

Technical Field

The present disclosure relates to the field of seismic processing technologies, and in particular, to a method, an apparatus, a device, and a storage medium for extracting effective seismic signals.

Background

And seismic data processing, namely removing noise interference signals in the seismic data and reserving effective seismic signals in the seismic data.

The frequency-space domain predictive filtering method is one of the most common seismic data processing methods at present. The frequency-space domain prediction filtering method is that a space prediction filter is arranged on a propagation path of an effective seismic signal along the propagation direction of the effective seismic signal, noise interference signals in seismic data are removed through the space prediction filter, and the effective seismic signal in the seismic data is reserved.

If the interference intensity is large and the signal-to-noise ratio is too low, the noise interference signal removed by the spatial prediction filter contains an effective seismic signal, that is, the effective seismic signal cannot be completely separated from the noise interference signal by the frequency-spatial domain prediction filtering, so that the fidelity of the processed effective seismic signal is poor.

Disclosure of Invention

The embodiment of the disclosure provides a method, a device, equipment and a storage medium for extracting effective signals in seismic data, which can effectively extract the effective signals in the seismic data. The technical scheme is as follows:

in one aspect, the present disclosure provides a method for extracting effective seismic signals, the method comprising:

acquiring seismic data;

carrying out noise suppression processing on the acquired seismic data to obtain a predicted seismic signal and a predicted noise interference signal;

obtaining a first autocorrelation function of the predicted seismic signal, a second autocorrelation function of the predicted noise interference signal, and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal;

determining an energy coefficient characteristic equation of the effective seismic signal based on the first autocorrelation function, the second autocorrelation function and the cross-correlation function, wherein the energy coefficient characteristic equation of the effective seismic signal is used for expressing an equation of a relation between an energy coefficient of the effective seismic signal and a characteristic factor, and the characteristic factor expresses a relation among the first autocorrelation function, the second autocorrelation function and the cross-correlation function;

determining an optimal effective seismic signal energy coefficient of the effective seismic signals based on the energy coefficient characteristic equation of the effective seismic signals, wherein the optimal effective seismic signal energy coefficient of the effective seismic signals is the energy coefficient of the effective seismic signals when the energy value of the second autocorrelation function is minimum;

an effective seismic signal is determined based on the optimal effective signal energy coefficient and the predicted seismic signal.

In an implementation manner of the embodiment of the present disclosure, the second autocorrelation function is:

the first autocorrelation function is:

the cross-correlation function is:

wherein N is_iRepresenting the predicted noise interference signal at time i, N_i+kRepresenting the predicted noise interference signal at time i + k, S_iRepresenting the predicted seismic signal at time i, S_i+kRepresenting the predicted seismic signal at time i + k;

k represents the sequence number of the delayed sampling points of the autocorrelation function, k is 0,1,2, …, and L is an integer;

i represents the time sample sequence number, i is 1,2, …, M represents the total number of time samples, M is a positive integer, and L is less than or equal to M.

In one implementation of the disclosed embodiment, determining an energy coefficient signature equation for the effective seismic signal based on the first autocorrelation function, the second autocorrelation function, and the cross-correlation function includes:

the following formula is adopted as an energy coefficient characteristic equation of the effective seismic signals:

wherein the content of the first and second substances,

α denotes the energy coefficient of the effective seismic signal, f₁、f₂、f₃、f₄And f₅Respectively, representing the characteristic factors.

In one implementation of the embodiments of the present disclosure, determining an optimal effective seismic signal energy coefficient of the effective seismic signal based on an energy coefficient feature equation of the effective seismic signal includes:

determining a cubic characteristic equation based on an energy coefficient characteristic equation of the effective seismic signal;

determining a characteristic root of the cubic characteristic equation;

if the cubic characteristic equation has one characteristic root, determining an optimal effective seismic signal energy coefficient based on the one characteristic root;

if the cubic characteristic equation has a plurality of characteristic roots, determining a plurality of effective signal energy coefficients based on the plurality of characteristic roots; respectively determining corresponding second autocorrelation function energy values based on the plurality of effective signal energy coefficients; and comparing the determined energy values of the second autocorrelation function, and taking the effective seismic signal energy coefficient corresponding to the minimum energy value of the second autocorrelation function as the optimal effective seismic signal energy coefficient.

In one implementation of the embodiments of the present disclosure, determining a cubic characteristic equation based on an energy coefficient characteristic equation of the significant seismic signals includes:

determining a cubic characteristic equation based on an effective signal energy coefficient expression and an energy coefficient characteristic equation of the effective seismic signal;

wherein the effective signal energy coefficient expression is:

the cubic characteristic equation is as follows:

γ³+g₁γ+g₂＝0，

wherein:

the three characteristic roots of the cubic characteristic equation are respectively:

wherein:

ω denotes an imaginary constant factor, l denotes an imaginary unit, l²＝-1。

In one implementation manner of the embodiment of the present disclosure, determining, based on the plurality of effective signal energy coefficients, corresponding second autocorrelation function energy values respectively includes:

calculating a second autocorrelation function energy value based on the following formula:

Q₁、Q₂and Q₃Representing the energy value of the second autocorrelation function, α₁、α₂And α₃Representing the effective signal energy coefficient.

In one implementation of the disclosed embodiment, the determining the effective seismic signal based on the optimal effective signal energy coefficient and the predicted seismic signal includes:

determining a valid seismic signal based on the formula:

wherein β_best＝1+α_best；

Representing the effective seismic signal, S_iRepresenting predicted seismic signals, α_bestRepresenting the best effective signal energy coefficient.

In another aspect, the present disclosure provides an effective seismic signal extraction device, including:

a first acquisition module configured to acquire seismic data;

the processing module is configured to perform noise suppression processing on the acquired seismic data to obtain a predicted seismic signal and a predicted noise interference signal;

a second acquisition module configured to acquire a first autocorrelation function of the predicted seismic signal, a second autocorrelation function of the predicted noise interference signal, and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal;

a first determination module configured to determine an energy coefficient characteristic equation of the effective seismic signal based on the first autocorrelation function, the second autocorrelation function and the cross-correlation function, the energy coefficient characteristic equation of the effective seismic signal being an equation representing a relationship between an energy coefficient of the effective seismic signal and a characteristic factor representing a relationship between the first autocorrelation function, the second autocorrelation function and the cross-correlation function;

a second determination module configured to determine an optimal effective seismic signal energy coefficient for the effective seismic signal based on an energy coefficient characteristic equation for the effective seismic signal, the optimal effective seismic signal energy coefficient for the effective seismic signal being an energy coefficient for the effective seismic signal at which a second autocorrelation function energy value is minimum;

a third determination module configured to determine a valid seismic signal based on the optimal valid signal energy coefficient and the predicted seismic signal.

In another aspect, the present disclosure provides a computer device comprising:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to perform any of the above methods of extracting significant seismic signals.

In another aspect, the present disclosure provides a storage medium having a computer program stored therein, the computer program being executed by a processor to implement the method of extracting effective seismic signals as described in any one of the above.

The technical scheme provided by the embodiment of the disclosure has the following beneficial effects:

in an embodiment of the disclosure, an energy coefficient signature equation for a valid seismic signal is determined by predicting a first autocorrelation function of the seismic signal, predicting a second autocorrelation function of the noise interference signal, and predicting a cross-correlation function of the seismic signal and the noise interference signal. The energy coefficient characteristic equation of the effective seismic signal is used for expressing the equation of the relation between the energy coefficient of the effective seismic signal and the characteristic factor, and the characteristic factor can express the relation among the first autocorrelation function, the second autocorrelation function and the cross-correlation function, so that the energy coefficient of the effective seismic signal when the energy value of the second autocorrelation function is minimum can be determined based on the energy coefficient characteristic equation of the effective seismic signal. Based on the energy coefficient of the effective seismic signal when the energy value of the second autocorrelation function is minimum, the effective seismic signal contained in the predicted noise interference signal can be extracted, the effective seismic signal is prevented from being removed as the noise interference signal, the finally determined effective seismic signal is more accurate, and the fidelity of the effective seismic signal is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic flow chart diagram of a method for extracting effective seismic signals according to an embodiment of the present disclosure;

FIG. 2 is a schematic flow chart diagram of a method for extracting effective seismic signals according to an embodiment of the present disclosure;

FIG. 3 illustrates a common midpoint gather seismic data containing noise;

FIG. 4 illustrates common midpoint gather data for a predicted seismic signal;

FIG. 5 illustrates a common midpoint gather data of a predicted noise interference signal;

FIG. 6 illustrates a common midpoint gather seismic data amplitude spectrum containing noise;

FIG. 7 illustrates a common midpoint gather data amplitude spectrum for a predicted seismic signal;

FIG. 8 illustrates a common midpoint gather data amplitude spectrum of a predicted noise interference signal;

FIG. 9 is common midpoint gather data for an effective seismic signal provided by embodiments of the present disclosure;

FIG. 10 is a common midpoint gather data of a noise interference signal provided by an embodiment of the present disclosure;

FIG. 11 is a common midpoint gather data amplitude spectrum of an effective seismic signal provided by an embodiment of the present disclosure;

FIG. 12 is a center gather data amplitude spectrum of a noise interference signal provided by an embodiment of the present disclosure;

FIG. 13 is a block diagram of an apparatus for extracting effective seismic signals provided by embodiments of the present disclosure;

fig. 14 is a block diagram of a computer device provided by an embodiment of the present disclosure.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic flow chart of an effective seismic signal extraction method provided by an embodiment of the present disclosure. Referring to fig. 1, the method includes:

step S11: seismic data are acquired.

In embodiments of the present disclosure, the seismic data may be artificially simulated seismic data. For example, the data may be data received by a receiving point after the wavelet excited by the air gun is reflected by the stratum, and the data is artificially simulated seismic data. Of course, the seismic data may also be real seismic data, which is not limited in this disclosure.

Step S12: and carrying out noise suppression processing on the acquired seismic data to obtain a predicted seismic signal and a predicted noise interference signal.

In the disclosed embodiments, the seismic data may be noise suppressed by a random noise attenuation method. For example, seismic data is noise suppressed by a frequency-space domain predictive filtering method.

Step S13: a first autocorrelation function of the predicted seismic signal, a second autocorrelation function of the predicted noise interference signal, and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal are obtained.

In the disclosed embodiment, a first autocorrelation function of the predicted seismic signal, a second autocorrelation function of the predicted noise interference signal, and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal are obtained, which facilitates subsequent determination of an effective seismic signal energy coefficient.

Wherein the first autocorrelation function represents the correlation of any two moments in the predicted seismic signal; the second autocorrelation function represents the correlation of any two moments in the predicted noise interference signal; the cross-correlation function represents the correlation of the predicted seismic signal and the predicted noise interference signal.

Step S14: and determining an energy coefficient characteristic equation of the effective seismic signals based on the first autocorrelation function, the second autocorrelation function and the cross-correlation function.

The energy coefficient characteristic equation of the effective seismic signals is used for expressing the relation between the energy coefficient of the effective seismic signals and characteristic factors, and the characteristic factors express the relation among the first autocorrelation function, the second autocorrelation function and the cross-correlation function.

In the embodiment of the disclosure, the energy coefficient characteristic equation of the effective seismic signal is determined, so that the energy coefficient of the effective seismic signal can be determined conveniently through the energy coefficient characteristic equation of the effective seismic signal.

Step S15: and determining the optimal effective seismic signal energy coefficient of the effective seismic signals based on the energy coefficient characteristic equation of the effective seismic signals.

Wherein the optimal effective seismic signal energy coefficient of the effective seismic signal is the energy coefficient of the effective seismic signal when the energy value of the second autocorrelation function is the smallest.

In the embodiment of the present disclosure, the energy of the second autocorrelation function may be represented by a sum of squares of the second autocorrelation function, and when the energy of the second autocorrelation function is the minimum, it is indicated that the proportion of the effective seismic signal in the predicted noise interference signal can be accurately reflected by using the energy coefficient of the effective seismic signal, and then the effective seismic signal in the predicted noise interference signal may be extracted based on the energy coefficient of the effective seismic signal.

Step S16: an effective seismic signal is determined based on the optimal effective signal energy coefficient and the predicted seismic signal.

In the embodiment of the disclosure, the energy coefficient of the effective seismic signal when the energy value of the second autocorrelation function is the minimum is taken as the energy coefficient of the optimal effective signal, and at this time, the effective seismic signal extracted from the predicted noise interference signal is more accurate, so that the fidelity of the effective seismic signal obtained by processing is improved.

In an embodiment of the disclosure, an energy coefficient signature equation for a valid seismic signal is determined by predicting a first autocorrelation function of the seismic signal, predicting a second autocorrelation function of the noise interference signal, and predicting a cross-correlation function of the seismic signal and the noise interference signal. The energy coefficient characteristic equation of the effective seismic signal is used for expressing the equation of the relation between the energy coefficient of the effective seismic signal and the characteristic factor, and the characteristic factor can express the relation among the first autocorrelation function, the second autocorrelation function and the cross-correlation function, so that the energy coefficient of the effective seismic signal when the energy value of the second autocorrelation function is minimum can be determined based on the energy coefficient characteristic equation of the effective seismic signal. Based on the energy coefficient of the effective seismic signal when the energy value of the second autocorrelation function is minimum, the effective seismic signal contained in the predicted noise interference signal can be extracted, the effective seismic signal is prevented from being removed as the noise interference signal, the finally determined effective seismic signal is more accurate, and the fidelity of the effective seismic signal is improved.

Fig. 2 is a schematic flow chart of an effective seismic signal extraction method provided by the embodiment of the disclosure. Referring to fig. 2, the method includes:

step S21: seismic data are acquired.

In the disclosed embodiment, the seismic data contains noise interference signals.

Step S22: and carrying out noise suppression processing on the acquired seismic data to obtain a predicted seismic signal and a predicted noise interference signal.

In the embodiment of the disclosure, the noise suppression processing may be performed on the seismic data by a frequency-space domain prediction filtering method to obtain a predicted seismic signal and a predicted noise interference signal.

In the disclosed embodiment, the seismic data is equal to a collection of predicted seismic signals and predicted noise interference signals. Namely:

T_i＝N_i+S_i(1)

in the formula (1), T_iSeismic data representing time i; n is a radical of_iA predicted noise interference signal representing time i; s_iRepresenting the predicted seismic signal at time i.

Due to energy and frequency leakage, the predicted noise interference signal contains valid seismic signals, and can be represented as:

α represents the energy coefficient of the effective seismic signal, namely the proportion of the effective seismic signal contained in the predicted noise interference signal;representing the noise interference signal at time i.

From equation (2), the noise interference signal in the seismic data is:

the seismic data, in turn, is equal to the collective set of valid seismic signals and noise interference signals, and the seismic data can be expressed as:

wherein:representing the valid seismic signal at time i.

From equations (3) and (4), it can be derived:

in equation (5), β is the effective signal energy coefficient in the predicted seismic signal.

β＝1+α (6)

The effective seismic signal can be finally determined by finding the value of alpha in the subsequent steps and then finding the value of beta through alpha.

FIG. 3 illustrates a Common Midpoint (CMP) gather seismic data containing noise. FIG. 4 illustrates common midpoint gather data for a predicted seismic signal. FIG. 5 illustrates a common midpoint gather data of a predicted noise interference signal. The data shown in fig. 5 is equal to the data shown in fig. 3 minus the data shown in fig. 4. Where the abscissa represents the number of common centers and the ordinate represents the time in milliseconds (ms) for the receiving point to receive data. The waveform change of the data in the figure indicates that the signal is received at the reception point at that time.

As can be seen from fig. 3, 4, and 5, the predicted noise interference signal obtained after the seismic data is processed by noise suppression still contains a strong effective seismic signal, which indicates that the energy leakage is serious and the fidelity of the obtained predicted seismic signal is poor.

The central point refers to the central point of the transmitting point and the receiving point when the seismic data are artificially simulated, and the seismic data of the central point obtained by each simulation experiment are called as central point gather data. The positions of the transmitting point and the receiving point can be adjusted in each experiment, the position of the central point is guaranteed to be unchanged, and the central point is called as a common central point.

FIG. 6 illustrates a common midpoint gather seismic data amplitude spectrum containing noise. FIG. 7 illustrates a common midpoint gather data amplitude spectrum for a predicted seismic signal. FIG. 8 illustrates a common midpoint gather data amplitude spectrum of a predicted noise interference signal. Wherein FIG. 6 represents the amplitude spectrum of the noise-containing common midpoint gather seismic data of FIG. 3, FIG. 7 represents the amplitude spectrum of the common midpoint gather data of the predicted seismic signal of FIG. 4, and FIG. 8 represents the amplitude spectrum of the common midpoint gather data of the predicted noise-interfering signal of FIG. 5. Wherein the abscissa represents frequency (f) in hertz (Hz), and the ordinate represents Amplitude (English: Amplitude)

As can also be seen from fig. 6, 7 and 8, the predicted noise interference signal obtained after processing the seismic data using noise suppression still contains part of the effective seismic signal.

Step S23: a first autocorrelation function of the predicted seismic signal, a second autocorrelation function of the predicted noise interference signal, and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal are obtained.

In the embodiment of the disclosure, the relationship between the predicted seismic signal and the predicted noise interference signal can be determined by the first autocorrelation function, the second autocorrelation function and the cross-correlation function, and the effective seismic signal in the predicted noise interference signal can be determined by the subsequent steps.

In an embodiment of the disclosure, the autocorrelation function of the noise interference signal in the seismic data is:

in equation (7): p (k) represents the autocorrelation function of the noise interference signal;representing the noise interference signal at time i + k.

Substituting equation (2) into equation (7) can yield:

from equation (8) it follows:

the second autocorrelation function is:

the first autocorrelation function is:

the cross-correlation function is:

wherein N is_iRepresenting the predicted noise interference signal at time i, N_i+kRepresenting the predicted noise interference signal at time i + k, S_iRepresenting the predicted seismic signal at time i, S_i+kRepresenting the predicted seismic signal at time i + k;

k represents the sequence number of the delayed sampling points of the autocorrelation function, k is 0,1,2, …, and L is an integer;

i denotes the time sample sequence number, i is 1,2, …, M denotes the total number of time samples, i.e. the time window parameter time sample number. M is a positive integer, and L is less than or equal to M.

Step S24: and determining an energy coefficient characteristic equation of the effective seismic signals based on the first autocorrelation function, the second autocorrelation function and the cross-correlation function.

The energy coefficient characteristic equation of the effective seismic signals is used for expressing the relation between the energy coefficient of the effective seismic signals and characteristic factors, and the characteristic factors express the relation among the first autocorrelation function, the second autocorrelation function and the cross-correlation function.

The process of determining the energy coefficient signature equation for a valid seismic signal is described below.

Substituting equations (9), (10), and (11) into equation (8) can yield:

P(k)＝a(k)-b(k)α+c(k)α²(12)

order the objective function

In equation (13), Q is the energy of the second autocorrelation function.

Let:

in the formula (14), f₁、f₂、f₃、f₄And f₅Respectively, representing the characteristic factors.

Substituting equation (14) into equation (13) yields:

Q＝f₁+f₂α+f₃α²+f₄α³+f₅α⁴(15)

the derivatives of α are simultaneously taken on both sides of equation (15), and let the derivatives be 0, the energy coefficient characteristic equation of the effective seismic signal can be obtained:

step S25: and determining a cubic characteristic equation based on the energy coefficient characteristic equation of the effective seismic signal.

In the embodiment of the disclosure, the cubic characteristic equation of the energy coefficient characteristic equation of the effective seismic signal is determined, so that the energy coefficient characteristic equation of the effective seismic signal is conveniently solved, and the energy coefficient of the effective seismic signal is further determined.

In the disclosed embodiment, the cubic characteristic equation may be expressed as:

γ³+g₁γ+g₂＝0 (17)

in formula (17), γ represents the characteristic root of the cubic characteristic equation, g₁And g₂Representing cubic eigen equation eigen coefficients.

Wherein:

step S26: the characteristic root of the cubic characteristic equation is determined.

Based on equation (17), three characteristic roots of the cubic characteristic equation can be determined as:

wherein:

in the formula (21), ω represents an imaginary constant factor, l represents an imaginary unit, and l represents an imaginary unit²＝-1。

Step S27: and determining the optimal effective seismic signal energy coefficient of the effective seismic signals based on the characteristic root of the cubic characteristic equation.

In the disclosed embodiment, if the cubic characteristic equation has one characteristic root, determining an optimal effective seismic signal energy coefficient based on the one characteristic root;

if the cubic characteristic equation has a plurality of characteristic roots, determining a plurality of effective signal energy coefficients based on the plurality of characteristic roots; respectively determining corresponding second autocorrelation function energy values based on the plurality of effective signal energy coefficients; and comparing the determined energy values of the second autocorrelation function, and taking the effective seismic signal energy coefficient corresponding to the minimum energy value of the second autocorrelation function as the optimal effective seismic signal energy coefficient.

How to determine the effective signal energy coefficient is described in detail below with reference to the following formula:

in the embodiment of the present disclosure, the effective signal energy coefficient expression is:

equation (16) has three solutions, α₁、α₂And α₃I.e. effective signal energy coefficient α₁、α₂And α₃Respectively as follows:

α will be mixed₁、α₂And α₃And respectively substituting the three values into the formula (15) to obtain three second autocorrelation function energy values.

Wherein Q is₁、Q₂And Q₃The minimum value α is the optimum effective signal energy coefficient α_best。

Namely:

how to determine the optimal effective signal energy coefficient is described below:

the eigenvalues of the cubic characteristic equation are:

(1) if the characteristic value D is>At 0, the cubic characteristic equation has only one real root γ₁，γ₁Corresponding α₁Is the optimum effective signal energy coefficient α_best：

α_best＝α₁(27)

(2) If the characteristic value D is<At 0, the cubic characteristic equation has three different real roots gamma₁、γ₂And gamma₃The corresponding effective signal energy coefficients are α respectively₁、α₂And α₃(ii) a Three second autocorrelation function energy values Q are calculated according to the following equation (24)₁、Q₂And Q₃。

Wherein Q is₁、Q₂And Q₃The minimum value α is the optimum effective signal energy coefficient α_bestAnd determines the optimum effective signal energy coefficient according to equation (25).

(3) If the characteristic value D is 0, and g₁＝g₂With 0, the characteristic equation has a triple zero, i.e. γ₁＝γ₂＝γ₃0, corresponding effective signal energy coefficient α₁＝α₂＝α₃Then the optimum effective signal energy coefficient α_best：

α_best＝α₁(28)

(4) If the characteristic value D is equal to 0, andthe characteristic equation has a single real root gamma₁One double root of solid Gamma₂＝γ₃The corresponding effective signal energy coefficients are α respectively₁And α₂(ii) a According to the formula (24), two noise autocorrelation function energy values Q are respectively₁And Q₂；Q₁And Q₂The α corresponding to the minimum value is the optimum effective signal energy coefficient α in the random noise attenuation processing noise_best：

Illustratively, the optimal effective signal energy coefficient α_bestSubstituting equation (30) to determine the effective signal energy coefficient β in the predicted seismic signal_best。

β_best＝1+α_best(30)

The effective seismic signal will then be determined from equation (31) for the effective seismic signal and the predicted seismic signal.

I.e. by means of which a valid seismic signal can be determined.

FIG. 9 is common midpoint gather data for an effective seismic signal provided by embodiments of the present disclosure. Fig. 10 is common midpoint gather data of a noise interference signal according to an embodiment of the disclosure. I.e., the data shown in fig. 9 is equal to the data shown in fig. 3 minus the data shown in fig. 10.

As can be seen from fig. 3, 9 and 10, after the seismic data is processed by using the method for extracting effective seismic signals of the present disclosure, fewer effective seismic signals are obtained from the noise interference signals, and the fidelity of the processed effective seismic signals is improved. The effective seismic signal energy is effectively recovered, and the energy of noise interference signals is very small.

FIG. 11 is a common midpoint gather data amplitude spectrum of an effective seismic signal provided by an embodiment of the disclosure. Fig. 12 is a center gather data amplitude spectrum of a noise interference signal provided by an embodiment of the present disclosure. FIG. 11 shows an amplitude spectrum of the common midpoint gather data for the effective seismic signal of FIG. 9, and FIG. 12 shows an amplitude spectrum of the common midpoint gather data for the noise interference signal of FIG. 10.

The amplitude spectra of fig. 11 and 8 are almost identical, which illustrates that the method provided by the present disclosure can extract the effective seismic signal from the predicted noise interference signal, and ensure the fidelity of the processed effective seismic signal. And as can be seen from fig. 12, after the seismic data is processed by using the method for extracting effective seismic signals of the present disclosure, the amount of effective seismic signals in the obtained noise interference signals is small, and the energy of the effective seismic signals is effectively recovered.

Fig. 13 is a block diagram of an effective seismic signal extraction device provided by an embodiment of the present disclosure. Referring to fig. 13, the effective seismic signal extraction apparatus includes:

a first acquisition module 101 configured to acquire seismic data;

a processing module 102 configured to perform noise suppression processing on the acquired seismic data to obtain a predicted seismic signal and a predicted noise interference signal;

a second obtaining module 103 configured to obtain a first autocorrelation function of the predicted seismic signal, a second autocorrelation function of the predicted noise interference signal, and a cross-correlation function of the predicted seismic signal and the predicted noise interference signal;

a first determining module 104 configured to determine an energy coefficient characteristic equation of the effective seismic signal based on the first autocorrelation function, the second autocorrelation function, and the cross-correlation function, the energy coefficient characteristic equation of the effective seismic signal being an equation representing a relationship between an energy coefficient of the effective seismic signal and a characteristic factor, the characteristic factor representing a relationship between the first autocorrelation function, the second autocorrelation function, and the cross-correlation function;

a second determination module 105 configured to determine an optimal effective seismic signal energy coefficient for the effective seismic signal based on an energy coefficient characteristic equation for the effective seismic signal, the optimal effective seismic signal energy coefficient for the effective seismic signal being an energy coefficient for the effective seismic signal at which the second autocorrelation function energy value is the smallest;

a third determination module 106 configured to determine a valid seismic signal based on the best valid signal energy coefficient and the predicted seismic signal.

Optionally, the second obtaining module 103 is configured to determine the first autocorrelation function, the second autocorrelation function and the cross-correlation function according to the following formulas.

The second autocorrelation function is:

the first autocorrelation function is:

the cross-correlation function is:

wherein N is_iRepresenting the predicted noise interference signal at time i, N_i+kRepresenting the predicted noise at time i + kInterference signal, S_iRepresenting the predicted seismic signal at time i, S_i+kRepresenting the predicted seismic signal at time i + k;

k represents the sequence number of the delayed sampling points of the autocorrelation function, k is 0,1,2, …, and L is an integer;

i represents the time sample sequence number, i is 1,2, …, M represents the total number of time samples, M is a positive integer, and L is less than or equal to M.

Optionally, the first determining module 104 is configured to adopt the following formula as an energy coefficient characteristic equation of the effective seismic signal:

wherein the content of the first and second substances,

α denotes the energy coefficient of the effective seismic signal, f₁、f₂、f₃、f₄And f₅Respectively, representing the characteristic factors.

Optionally, the second determining module 105 is configured to determine a cubic characteristic equation based on an energy coefficient characteristic equation of the effective seismic signal; the characteristic root of the cubic characteristic equation is determined.

If the cubic characteristic equation has one characteristic root, determining the optimal effective seismic signal energy coefficient based on the characteristic root; if the cubic characteristic equation has a plurality of characteristic roots, determining a plurality of effective signal energy coefficients based on the plurality of characteristic roots; respectively determining corresponding second autocorrelation function energy values based on a plurality of effective signal energy coefficients; and comparing the determined energy values of the second autocorrelation function, and taking the effective seismic signal energy coefficient corresponding to the minimum energy value of the second autocorrelation function as the optimal effective seismic signal energy coefficient.

Optionally, the second determining module 105 is configured to determine a cubic characteristic equation based on the effective signal energy coefficient expression and the energy coefficient characteristic equation of the effective seismic signal.

Wherein the effective signal energy coefficient expression is:

the cubic characteristic equation is:

γ³+g₁γ+g₂＝0；

wherein:

the three characteristic roots of the cubic characteristic equation are respectively:

wherein:

ω denotes an imaginary constant factor, l denotes an imaginary unit, l²＝-1。

Optionally, the second determining module 105 is configured to calculate the second autocorrelation function energy value based on the following formula:

Q₁、Q₂and Q₃Representing the energy value of the second autocorrelation function.

Optionally, the third determination module 106 is configured to determine the effective seismic signal based on the following formula:

wherein β_best＝1+α_best；

Representing the effective seismic signal, S_iRepresenting predicted seismic signals, α_bestRepresenting the best effective signal energy coefficient.

It should be noted that: in the above embodiment, when the effective seismic signal is extracted, only the division of the functional modules is used for illustration, and in practical applications, the function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules, so as to complete all or part of the functions described above. In addition, the effective seismic signal extraction device provided by the above embodiment and the effective seismic signal extraction method embodiment belong to the same concept, and the specific implementation process thereof is described in the method embodiment, and is not described herein again.

Fig. 14 is a block diagram of a computer device provided by an embodiment of the present disclosure. The computer device 400 may be a desktop computer, a server, or other type of device. Referring to fig. 14, computer device 400 may include one or more of the following components: a processing component 402, a memory 404, a power component 406, a multimedia component 408, an audio component 410, an interface for input/output (I/O) 412, a sensor component 414, and a communication component 416.

The processing component 402 generally controls overall operation of the computer device 400, such as operations associated with display, telephone calls, data communications, camera operations, and recording operations. The processing component 402 may include one or more processors 420 to execute instructions to perform all or a portion of the steps of the methods described above. Further, the processing component 402 can include one or more modules that facilitate interaction between the processing component 402 and other components. For example, the processing component 402 can include a multimedia module to facilitate interaction between the multimedia component 408 and the processing component 402.

The memory 404 is configured to store various types of data to support operations at the computer device 400. Examples of such data include instructions for any software program or method operating on computer device 400, contact data, phonebook data, messages, pictures, videos, and so forth. The memory 404 may be implemented by any type or combination of volatile or non-volatile memory devices such as Static Random Access Memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic or optical disks.

The power components 406 provide power to the various components of the computer device 400. Power components 406 may include a power management system, one or more power sources, and other components associated with generating, managing, and distributing power for computer device 400.

The multimedia component 408 includes a screen that provides an output interface between the computer device 400 and the user. In some embodiments, the screen may include a Liquid Crystal Display (LCD) and a Touch Panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive an input signal from a user. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor may not only sense the boundary of a touch or slide action, but also detect the duration and pressure associated with the touch or slide operation.

In some embodiments, the multimedia component 408 includes a front facing camera and/or a rear facing camera. The front-facing camera and/or the rear-facing camera may receive external multimedia data when the computer device 400 is in an operating mode, such as a shooting mode or a video mode. Each front camera and rear camera may be a fixed optical lens system or have a focal length and optical zoom capability.

The audio component 410 is configured to output and/or input audio signals. For example, the audio component 410 includes a Microphone (MIC) configured to receive external audio signals when the computer device 400 is in an operational mode, such as a call mode, a recording mode, and a voice recognition mode. The received audio signals may further be stored in the memory 404 or transmitted via the communication component 416. In some embodiments, audio component 410 also includes a speaker for outputting audio signals.

The I/O interface 412 provides an interface between the processing component 402 and peripheral interface modules, which may be keyboards, click wheels, buttons, etc. These buttons may include, but are not limited to: a home button, a volume button, a start button, and a lock button.

The sensor component 414 includes one or more sensors for providing various aspects of status assessment for the computer device 400. For example, the sensor component 414 can detect an open/closed state of the computer device 400, the relative positioning of components, such as a display and keypad of the computer device 400, the sensor component 414 can also detect a change in the position of the computer device 400 or a component of the computer device 400, the presence or absence of user contact with the computer device 400, the orientation or acceleration/deceleration of the computer device 400, and a change in the temperature of the computer device 400. The sensor assembly 414 may include a proximity sensor configured to detect the presence of a nearby object without any physical contact. The sensor assembly 414 may also include a light sensor, such as a CMOS or CCD image sensor, for use in imaging software. In some embodiments, the sensor assembly 414 may also include an acceleration sensor, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

The communication component 416 is configured to facilitate wireless communication between the computer device 400 and other devices. In the disclosed embodiment, the communication component 416 may access a wireless network based on a communication standard, such as 2G, 3G, 4G, or 5G, or a combination thereof, so as to implement the physical downlink control signaling detection. In an exemplary embodiment, the communication component 416 receives broadcast signals or broadcast related information from an external broadcast management system via a broadcast channel. Optionally, the communication component 416 further comprises an NFC module.

In an exemplary embodiment, the computer device 400 may be implemented by one or more software Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), controllers, micro-controllers, microprocessors or other electronic components for performing the above-described method of extracting effective seismic signals.

In an exemplary embodiment, a non-transitory computer-readable storage medium comprising instructions, such as the memory 404 comprising instructions, that may be executed by the processor 420 of the computer device 400 to perform the above-described method of extracting valid seismic signals is also provided. For example, the non-transitory computer readable storage medium may be a ROM, a Random Access Memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.

The above description is intended to be exemplary only and not to limit the present disclosure, and any modification, equivalent replacement, or improvement made without departing from the spirit and scope of the present disclosure is to be considered as the same as the present disclosure.