A method for controlling frequency gain of seismic data

Abstract

The present invention relates to a method for controlling the frequency gain of seismic data. The method comprises: obtaining seismic data, performing spectrum analysis using Fourier transform, and obtaining an actual amplitude spectrum X1(f); selecting an expected frequency band range, and presetting an expected main frequency w of a target sub-wave according to the expected frequency band range. m , the expected octave band width and frequency w, and the octave wavelet method are used to obtain the expected amplitude spectrum X2(f); the ratio of the actual amplitude spectrum X1(f) to the expected amplitude spectrum X2(f) is calculated to obtain the frequency domain gain factor H(f); the amplitude spectrum of the target frequency band is selected, multiplied by the frequency domain gain factor, and the seismic data x2(t) after frequency gain control is obtained. The scheme provided in this application can highlight the target frequency band components of the target body (such as the division of large structural units, the detailed characterization of sand bodies, etc.) according to actual needs, so as to obtain the result profiles for different interpretation purposes, and further meet the more refined display needs in seismic data processing.

Description

Technical Field

[0001] The present application relates to the technical field of seismic data processing, and in particular to a method for controlling frequency gain of seismic data. Background Art

[0002] Seismic exploration technology is a technology that uses artificially stimulated seismic waves to propagate in the strata to explore the underground geological conditions. When seismic waves stimulated somewhere on the ground propagate underground, they will generate reflected waves or refracted waves returning to the ground when they encounter the interface of strata with different elasticity. These waves are recorded by seismic detectors to obtain seismic data. By analyzing the characteristics of the recorded waves (such as the propagation time of the waves and the vibration shape, etc.), the depth and shape of these interfaces can be determined more accurately, and the lithology of the strata can be judged.

[0003] The receiving record of a seismic detector is a seismic channel. The recording content of a seismic channel is mainly a seismic wave. A seismic wave is a curve of amplitude changing with time. Due to the geometric diffusion effect of seismic waves and the influence of stratum absorption attenuation under complex geological conditions, the amplitude of seismic waves decays with the increase of propagation distance or time, and the attenuation of amplitude also varies with different frequencies. High-frequency components decay faster than low-frequency components, which reduces the frequency of the main frequency in the seismic data, causing energy imbalance in the shot collection record, seriously affecting the imaging accuracy, and then reducing the resolution of seismic data. In order to improve the resolution of seismic data, seismic energy balance processing is required for seismic data.

[0004] In the related technology, there are two main energy balancing methods: one is true amplitude recovery, whose main processing steps include wavefront diffusion energy compensation, formation absorption energy compensation and surface consistency energy adjustment, etc. However, in actual engineering, the parameters such as the velocity and Q value of the underground medium are unknown, so the energy balancing effect of true amplitude recovery will be affected. The other is automatic gain control (AGC), which is based on statistical principles and counts the sampled amplitude in the tx domain according to a given time window, and reconstructs the sampled amplitude based on the statistical median, average or root mean square value to achieve the purpose of amplitude balancing. Although this method can make the data amplitude tend to be balanced, it will also destroy the relative properties of the amplitude.

[0005] The above energy balance methods all directly control the gain of the time domain amplitude and cannot consider the data display effect from the perspective of frequency component energy; that is, when processing and interpreting seismic data, it is impossible to highlight the target frequency band components of the interpretation target body (such as large structural unit division, sand body detail characterization, etc.) according to actual needs, so as to obtain result profiles for different interpretation purposes, and cannot meet the more refined display needs in seismic data processing work. Summary of the invention

[0006] In order to overcome the problems existing in the related art, the present application provides a seismic data frequency gain control method, which can highlight the target frequency band components of the interpretation target body (such as large structural unit division, sand body detail characterization, etc.) according to actual needs, thereby obtaining profiles of results for different interpretation purposes, and further meet the more refined display needs in seismic data processing work.

[0007] The first aspect of the present application provides a method for controlling frequency gain of seismic data, comprising the following steps:

[0008] Obtain seismic data, perform spectrum analysis using Fourier transform, and obtain the actual amplitude spectrum X1(f);

[0009] Select the expected frequency band range and preset the expected main frequency w of the target sub-wave according to the expected frequency band range m , the desired octave bandwidth σ1 and frequency w, and the desired amplitude spectrum X2(f) is obtained by using the octave wavelet method;

[0010] Calculate the ratio of the actual amplitude spectrum X1(f) to the expected amplitude spectrum X2(f) to obtain a frequency domain gain factor H(f);

[0011] The amplitude spectrum of the target frequency band is selected and multiplied by the frequency domain gain factor to obtain the seismic data x2(t) after frequency gain control.

[0012] In one embodiment, the method of using a frequency doubling wavelet method to obtain a desired amplitude spectrum X2(f) comprises:

[0013] The frequency w of the target sub-wave and the main frequency w m Convert the frequency w' and main frequency w' into logarithmic coordinate system m ,

[0014] With frequency w′ and main frequency w′ m Using the main frequency w′ m The symmetrical and smooth function curve constructs the amplitude spectrum curve, and obtains the amplitude spectrum curve in the logarithmic coordinate system;

[0015] The amplitude spectrum curve in the logarithmic coordinate system is converted into an amplitude spectrum curve in the non-logarithmic coordinate system to obtain the amplitude spectrum curve in the non-logarithmic coordinate system, and the amplitude spectrum curve in the non-logarithmic coordinate system is used as the expected amplitude spectrum X2(f).

[0016] In one embodiment, the frequency w of the target wavelet and the main frequency w m Convert the frequency w' and main frequency w' into logarithmic coordinate system m ,include:

[0017] The frequency w of the target sub-wave and the main frequency w mPerform logarithmic transformation to obtain the frequency w′ and main frequency w′ in the logarithmic coordinate system m .

[0018] In one embodiment, the seismic data includes: an effective frequency band range of [f min , f max 】, the actual main frequency is f m and the octave bandwidth σ.

[0019] In one implementation, the selecting the expected frequency band range includes: selecting a value range consistent with the effective frequency band range as the expected frequency band range.

[0020] In one embodiment, acquiring seismic data includes: acquiring a seismic stacking profile.

[0021] In one embodiment, before obtaining the seismic stacking profile, the process includes: obtaining a track gather, and stacking the track gather after dynamic correction to obtain the seismic stacking profile.

[0022] In one embodiment, the expected main frequency w of the preset target sub-wave is m Including: within the expected frequency band range, according to different interpretation requirements, presetting the expected main frequency w of the target sub-wave m The numerical value of .

[0023] In one embodiment, the selecting the amplitude spectrum of the target frequency band and multiplying it by the frequency domain gain factor to obtain the seismic data x2(t) after frequency gain control comprises:

[0024] The amplitude spectrum of the selected target frequency band is multiplied by the frequency domain gain factor to obtain a frequency domain amplitude spectrum;

[0025] The frequency domain amplitude spectrum is subjected to inverse Fourier transformation to obtain a time amplitude spectrum, and the time domain amplitude spectrum is used as the seismic data x2(t) after frequency gain control.

[0026] In one embodiment, the calculation formula of the frequency domain gain factor includes: H(f)=X2(f) / X1(f); wherein X1(f) is the actual amplitude spectrum and X2(f) is the expected amplitude spectrum.

[0027] The technical solution provided by the present application may include the following beneficial effects: after acquiring seismic data, the time domain display of the seismic wave curve is converted into the frequency domain display through Fourier transform, and the spectrum analysis is performed to obtain the actual amplitude spectrum, so as to know the amplitude of each frequency component; then the expected amplitude spectrum is constructed by presetting the expected main frequency and expected frequency band range of the target sub-wave; since the octave spectrum symmetric seismic wavelet can be obtained by adopting the octave wavelet method, it has the characteristics of rich low frequency and wide high frequency. When it is applied to seismic data processing as an ideal seismic wavelet, by setting the value of the expected main frequency, the energy of the target frequency band component can be highlighted in a targeted manner according to different interpretation requirements; the specific target frequency band can be adjusted by setting the main frequency of the expected amplitude spectrum, and the specific gain degree can be determined by the frequency domain gain factor. The amplitude spectrum of the seismic data is multiplied by the frequency domain gain factor to obtain the amplitude spectrum of the target result profile, and then it is transformed to the time domain through inverse Fourier transform, and the obtained time domain amplitude spectrum is used as the seismic data after frequency gain control, so as to meet the more refined display requirements in seismic data processing.

[0028] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0030] Figure 1 It is a flow chart of a method for controlling frequency gain of seismic data shown in an embodiment of the present application;

[0031] Figure 2 is an actual ocean seismic profile diagram shown in an embodiment of the present application;

[0032] Figure 3 is an actual ocean seismic profile amplitude spectrum shown in the embodiment of the present application;

[0033] Figure 4 It is the expected amplitude spectrum of the expected main frequency of the preset target sub-wave of 10 Hz shown in the embodiment of the present application;

[0034] Figure 5 It is the expected amplitude spectrum of the expected main frequency of the preset target sub-wave of 30 Hz shown in the embodiment of the present application;

[0035] Figure 6 It is the expected amplitude spectrum of the expected main frequency of the preset target sub-wave of 50 Hz shown in the embodiment of the present application;

[0036] Figure 7 It is a marine seismic profile with a main frequency of 10 Hz after applying the frequency domain gain factor shown in the embodiment of the present application;

[0037] Figure 8 It is an amplitude spectrum of a marine seismic profile with a main frequency of 10 Hz after applying a frequency domain gain factor as shown in the embodiment of the present application;

[0038] Fig. 9 It is a marine seismic profile with a main frequency of 30 Hz after applying the frequency domain gain factor shown in the embodiment of the present application;

[0039] Fig.10 It is an amplitude spectrum of a marine seismic profile with a main frequency of 30 Hz after applying a frequency domain gain factor as shown in the embodiment of the present application;

[0040] Fig.11 It is a marine seismic profile with a main frequency of 50 Hz after applying the frequency domain gain factor shown in the embodiment of the present application;

[0041] Fig.12 This is an amplitude spectrum of a marine seismic profile with a main frequency of 50 Hz after applying a frequency domain gain factor as shown in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0043] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0044] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0045] At present, the energy balance methods for seismic data all directly control the gain of the time domain amplitude, and are unable to consider the data display effect from the perspective of frequency component energy; that is, when processing and interpreting seismic data, it is impossible to highlight the target frequency band components of the interpretation target body according to actual needs, thereby obtaining result profiles for different interpretation purposes, and cannot meet the more refined display needs in seismic data processing work.

[0046] In response to the above problems, an embodiment of the present application provides a method for controlling the frequency gain of seismic data, which can highlight the target frequency band components of the interpretation target body (such as the division of large structural units, detailed characterization of sand bodies, etc.) according to actual needs, thereby obtaining profiles of results for different interpretation purposes, and further meet the more refined display needs in seismic data processing work.

[0047] The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0048] Embodiment 1

[0049] See also Figure 1 , Figure 1 It is a flow chart of the seismic data frequency gain control method shown in the embodiment of the present application.

[0050] A seismic data frequency gain control method of the present application comprises the following steps:

[0051] S1. Obtain seismic data, perform spectrum analysis using Fourier transform, and obtain the actual amplitude spectrum X1(f).

[0052] In S1, the acquisition of seismic data includes: acquiring a seismic stacked profile; before acquiring the seismic stacked profile, it includes: acquiring a track gather. Specifically, the reception record of a seismic detector is a seismic track, and the collection of reception records of multiple seismic detectors (i.e., the collection of multiple seismic tracks) is a track gather; the track gather is stacked after dynamic correction to obtain a seismic stacked profile.

[0053] According to the seismic stacking profile, seismic data can be analyzed and obtained, mainly including: the effective frequency band range is [f min, f max 】, the actual main frequency is f m And the octave bandwidth σ. Among them, the effective frequency band range refers to the frequency band width occupied by the signal, that is, the effective bandwidth. The larger the effective frequency band range, the better the effect; f min Indicates the lowest frequency in the effective frequency band, f max Indicates the highest frequency in the effective frequency band; the actual main frequency f m It refers to the frequency component corresponding to the strongest energy fluctuation on the seismic superposition section, which can reflect the level of seismic resolution. m The value range of f is: min ≤f m ≤f max .

[0054] The octave band width (octave band) σ is generally used to define the seismic wavelet band width, and its formula is σ = log2 (f max / f min ), where f min Indicates the lowest frequency in the effective frequency band, f max Indicates the highest frequency in the effective frequency band; the larger the value of the octave bandwidth σ, the better the effect; for example, for 5Hz and 10Hz with the same spectral component energy, although there is only a difference of 5Hz, the frequency difference is one octave. For 50Hz and 55Hz with the same spectral component energy, there is also a difference of 5Hz, but only 10% of the octave. For the two groups of data ((5Hz, 10Hz), (50Hz, 55Hz)), although the former and the latter groups differ by 5Hz, they are not comparable in terms of octave, while the comparison of the energy of the two groups of spectral components of 5Hz and 10Hz, 50Hz and 100Hz is more comparable. Therefore, in the sense of octave, examining the frequency energy relationship (spectral morphology) has better physical meaning.

[0055] Based on the seismic data, the Fourier transform is used to convert the time domain display of the seismic wave curve into the frequency domain display, and the spectrum analysis is performed to obtain the actual amplitude spectrum X1(f). The specific formula is X1(f)=FFT[x1(t)]. According to the actual amplitude spectrum, the frequency component can be obtained and the amplitude of each frequency component can be known.

[0056] S2. Select the expected frequency band range and preset the expected main frequency w of the target sub-wave according to the expected frequency band range. m , the expected octave bandwidth σ1 and frequency w, and the octave wavelet method are used to obtain the expected amplitude spectrum X2(f).

[0057] In S2, in order to avoid distortion of the seismic profile, the selecting of the expected frequency band range includes: selecting a value range consistent with the effective frequency band range as the expected frequency band range, specifically, the effective frequency band range [f min , f max 】is [6, 100], then the expected frequency band range [f min , f max 】 is also [6, 100]; the expected main frequency w m The value of f min ≤w m ≤f max ; Since the effective frequency band range is consistent with the expected frequency band range, the expected octave band width σ1 is consistent with the value of the octave band width σ; the target wavelet is an ideal seismic wavelet, and its frequency w is f min ≤w≤f max , the target wavelet is processed as input, and further, the frequency-doubling wavelet method is used to obtain the expected amplitude spectrum X2(f).

[0058] The method of using the frequency doubling wavelet method to obtain the expected amplitude spectrum X2(f) specifically includes:

[0059] The frequency w of the target sub-wave and the main frequency w m Convert the frequency w' and main frequency w' into logarithmic coordinate system m Specifically, the frequency w of the target sub-wave and the main frequency w m Perform logarithmic transformation to obtain the frequency w′ and main frequency w′ in the logarithmic coordinate system m For example, the logarithm with a base of 2 can be used for conversion, or the logarithm with a base of other positive integer values, for example, the logarithm with a base of 10 can be used for conversion; with frequency w′ and main frequency w′ m Using the main frequency w′ m A symmetrical and smooth function curve is used to construct an amplitude spectrum curve to obtain an amplitude spectrum curve in a logarithmic coordinate system. The amplitude spectrum curve in the logarithmic coordinate system is then converted into an amplitude spectrum curve in a non-logarithmic coordinate system to obtain an amplitude spectrum curve in a non-logarithmic coordinate system. The amplitude spectrum curve in the non-logarithmic coordinate system is used as the expected amplitude spectrum X2(f).

[0060] It should be noted that the present application uses the frequency-doubled wavelet method to construct the expected amplitude spectrum. Other methods can also be used to construct the expected amplitude spectrum, as long as a smooth amplitude spectrum can be obtained and the constructed expected amplitude spectrum must meet the spectral characteristics of the frequency-doubled wavelet.

[0061] S3. Calculate the ratio of the actual amplitude spectrum X1(f) to the expected amplitude spectrum X2(f) to obtain a frequency domain gain factor H(f).

[0062] In S3, the actual amplitude spectrum is divided by the expected amplitude spectrum in the frequency domain to obtain the frequency domain gain factor H(f). The specific calculation formula is H(f)=X2(f) / X1(f), where X1(f) is the actual amplitude spectrum and X2(f) is the expected amplitude spectrum. By calculating the frequency domain gain factor, the gain coefficient required for the actual amplitude spectrum to achieve the expected amplitude spectrum effect can be known.

[0063] S4. Select the amplitude spectrum of the target frequency band, multiply it by the frequency domain gain factor, and obtain the seismic data x2(t) after frequency domain gain control.

[0064] In S4, the amplitude spectrum of the target frequency band is selected and multiplied by the frequency domain gain factor to obtain the frequency domain amplitude spectrum; the frequency domain amplitude spectrum is subjected to inverse Fourier transform to obtain the time domain amplitude spectrum, and the time domain amplitude spectrum is used as the seismic data x2(t) after frequency gain control, wherein the calculation formula of x2(t) is: x2(t)=ifft[X1(f)H(f)]; wherein X1(f) is the actual amplitude spectrum, and H(f) is the frequency domain gain factor; it should be noted that the amplitude spectrum of the target frequency band can be the entire actual amplitude spectrum or any segment of the actual amplitude spectrum.

[0065] In the first embodiment, after acquiring the seismic data, the seismic wave curve time domain display is converted into frequency domain display through Fourier transform, and the spectrum analysis is performed to obtain the actual amplitude spectrum, so as to know the amplitude of each frequency component; then the expected amplitude spectrum is constructed by presetting the expected main frequency and expected frequency band range of the target wavelet; since the octave spectrum symmetric seismic wavelet can be obtained by adopting the octave wavelet method, it has the characteristics of rich low frequency and wide high frequency. When it is applied to seismic data processing as an ideal seismic wavelet, by setting the value of the expected main frequency, the energy of the target frequency band component can be highlighted in a targeted manner according to different interpretation requirements; the specific target frequency band can be adjusted by setting the main frequency of the expected amplitude spectrum, and the specific gain degree can be determined by the frequency domain gain factor. The amplitude spectrum of the seismic data is multiplied by the frequency domain gain factor to obtain the amplitude spectrum of the target result section, and then the inverse Fourier transform is performed to the time domain, and the obtained time domain amplitude spectrum is used as the seismic data after frequency gain control, so as to meet the more refined display requirements in the seismic data processing work.

[0066] Embodiment 2

[0067] In order to meet different geological interpretation needs and effectively improve the interpretation ability of seismic data, this application proposes a corresponding solution. Please refer to Figure 2-Figure 12 , specifically:

[0068] Based on the structure of the above embodiment 1, the expected main frequency w of the preset target sub-wave is mIncluding: within the expected frequency band range, according to different interpretation requirements, presetting the expected main frequency w of the target sub-wave m Specifically, in order to highlight the target frequency band components of the target body (such as the division of large structural units, the detailed characterization of sand bodies, etc.) according to actual needs, the expected main frequency w m The setting principle is: the expected main frequency w m The lower the value of, the more the frequency domain gain (FGC) processing can highlight the seismic data on the main stratigraphic interfaces and tectonic units. m The higher the value, the more the frequency domain gain (FGC) processing can enhance the seismic data's ability to depict local details of the formation.

[0069] like Figure 2-Figure 3 As shown in FIG. 1 , seismic data of a certain sea area is selected, and Fourier transform is used to perform spectrum analysis on the full-time window of the seismic data. The full-time window takes the record length of the seismic trace. For example, in this embodiment, the range of the full-time window is 0-12s. According to the acquired seismic data, its effective frequency band range is 6-90Hz. After spectrum analysis, the following is obtained: Figure 3 The actual amplitude spectrum is shown.

[0070] According to the effective frequency band range, the expected frequency band range can be obtained to be 6-90Hz, and the expected main frequency w of the target sub-wave is preset respectively. m The expected main frequency w is 10 Hz (low frequency), 30 Hz and 50 Hz (high frequency), and the frequency doubling wavelet method in step S2 is used to construct the expected main frequency w m is the expected amplitude spectrum of 10Hz, 30Hz and 50Hz, and the expected amplitude spectrum is as follows: Figure 4-Figure 6 shown.

[0071] Will Figure 3 The actual amplitude spectra shown are respectively Figure 4 , Figure 5 and Figure 6 The desired amplitude spectra shown are divided to obtain three frequency domain gain factors that highlight different main frequencies.

[0072] The entire actual amplitude spectrum is selected as the amplitude spectrum of the target frequency band, and three frequency domain gain factors that highlight different main frequencies are multiplied respectively to obtain frequency domain amplitude spectra of three different main frequencies; the frequency domain amplitude spectra of the three different main frequencies are respectively transformed by inverse Fourier transform, such as Figure 7-Figure 12 As shown, time domain amplitude spectra of three different main frequencies and frequency domain gain (FGC) profiles of three different main frequencies are obtained, which are the seismic data x2(t) after frequency gain control.

[0073] By comparison Figure 2 and Figure 7 , Figure 3 and Figure 8It can be seen that when the preset expected main frequency is 10Hz, Figure 7 As shown in Figure 2, the low-frequency component energy of the frequency domain gain (FGC) profile with an expected main frequency of 10 Hz is more prominent, which has a better display effect on the overall geological structure trend; Figure 2 and Fig.11 , Figure 3 and Fig.12 It can be seen that when the expected main frequency of the preset target sub-wave is 50Hz, Fig.11 As shown in the figure, the high-frequency component energy of the frequency domain gain (FGC) profile with the expected main frequency of 50Hz is more prominent, which has a better display effect for the local high-frequency detail characterization. Moreover, it can be seen from the amplitude spectrum of the seismic data after the application of the frequency domain gain (FGC) that the seismic data after the application of the frequency domain gain (FGC) can well highlight the energy of the expected main frequency, which can highlight the low-frequency components of the seismic data for the overall geological structure trend display; it can also highlight the high-frequency components of the seismic data for the local geological structure detail display.

[0074] It should be noted that the low frequency in this embodiment is a relative concept, which does not specifically mean that the frequency within a certain numerical range is low frequency, but means that in the amplitude spectrum curve of the seismic wavelet, the frequency range with relatively low frequency compared with the high frequency is low frequency. For example, relative to the high frequency of 50 Hz, the frequency of 10 Hz can be considered as low frequency.

[0075] In the embodiment of the present application, by setting the expected main frequency w m The target frequency band components of the target body can be highlighted and interpreted according to actual needs; when the overall geological structure trend needs to be interpreted, the expected main frequency w of the target sub-wave can be preset m The frequency domain gain (FGC) is low frequency, and the seismic data can highlight the display of the main stratigraphic interfaces and tectonic units after processing; when it is necessary to interpret the local details, the expected main frequency w of the target wavelet can be preset. m For high frequencies, frequency domain gain (FGC) processing can enhance the ability of seismic data to depict local details of the strata.

[0076] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated again here.

[0077] The scheme of the present application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. Those skilled in the art should also know that the steps in the method of the embodiment of the present application can be adjusted in order, combined and deleted according to actual needs.

[0078] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system and method according to multiple embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a part of a module, a program segment or a code, and the part of the module, the program segment or the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or the flow chart, and the combination of the square boxes in the block diagram and / or the flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0079] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for controlling frequency gain of seismic data, characterized in that: The steps include: Obtain seismic data, perform spectrum analysis using Fourier transform, and obtain the actual amplitude spectrum X1(f); Select the expected frequency band range and preset the expected main frequency w of the target sub-wave according to the expected frequency band range m , the desired octave bandwidth σ1 and frequency w, and the desired amplitude spectrum X2(f) is obtained by using the octave wavelet method; Calculate the ratio of the actual amplitude spectrum X1(f) to the expected amplitude spectrum X2(f) to obtain a frequency domain gain factor H(f); Selecting the amplitude spectrum of the target frequency band, multiplying it by the frequency domain gain factor, and obtaining the seismic data x2(t) after frequency gain control; The method of using the frequency doubling wavelet to obtain the expected amplitude spectrum X2(f) includes: The frequency w of the target sub-wave and the main frequency w m Convert the frequency w' and main frequency w' into logarithmic coordinate system m , With frequency w′ and main frequency w′ m Using the main frequency w′ m The symmetrical and smooth function curve constructs the amplitude spectrum curve, and obtains the amplitude spectrum curve in the logarithmic coordinate system; The amplitude spectrum curve in the logarithmic coordinate system is converted into an amplitude spectrum curve in the non-logarithmic coordinate system to obtain the amplitude spectrum curve in the non-logarithmic coordinate system, and the amplitude spectrum curve in the non-logarithmic coordinate system is used as the expected amplitude spectrum X2(f).

2. The seismic data frequency gain control method according to claim 1, characterized in that: The frequency w of the target sub-wave and the main frequency w m Convert the frequency w' and main frequency w' into logarithmic coordinate system m ,include: The frequency w of the target sub-wave and the main frequency w m Perform logarithmic transformation to obtain the frequency w′ and main frequency w′ in the logarithmic coordinate system m .

3. The seismic data frequency gain control method according to claim 1, characterized in that: The seismic data includes: effective frequency band range is [f min , f max 】, the actual main frequency is f m and the octave bandwidth σ.

4. The seismic data frequency gain control method according to claim 3, characterized in that: The selecting the expected frequency band range includes: selecting a value range consistent with the effective frequency band range as the expected frequency band range.

5. The seismic data frequency gain control method according to claim 1, characterized in that: The obtaining of seismic data includes: obtaining a seismic stacking profile.

6. The seismic data frequency gain control method according to claim 5, characterized in that: Before obtaining the seismic stacking profile, the method includes: obtaining a track gather, and stacking the track gather after dynamic correction to obtain the seismic stacking profile.

7. The seismic data frequency gain control method according to claim 1, characterized in that: The expected main frequency w of the preset target sub-wave m Including: within the expected frequency band range, according to different interpretation requirements, presetting the expected main frequency w of the target sub-wave m The numerical value of .

8. The seismic data frequency gain control method according to claim 1, characterized in that: The amplitude spectrum of the selected target frequency band is multiplied by the frequency domain gain factor to obtain the seismic data x2(t) after frequency gain control, including: Selecting an amplitude spectrum of a target frequency band, and multiplying it by the frequency domain gain factor to obtain a frequency domain amplitude spectrum; The frequency domain amplitude spectrum is subjected to inverse Fourier transformation to obtain a time domain amplitude spectrum, and the time domain amplitude spectrum is used as the seismic data x2(t) after frequency gain control.

9. The seismic data frequency gain control method according to claim 1, characterized in that: The calculation formula of the frequency domain gain factor is H(f)=X2(f) / X1(f); Among them, X1(f) is the actual amplitude spectrum, and X2(f) is the expected amplitude spectrum.

Images