CN111323819B - Earthquake fracture position detection method and device - Google Patents
Earthquake fracture position detection method and device Download PDFInfo
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Abstract
The invention provides a method and a device for detecting a seismic fracture position, wherein the method comprises the steps of obtaining a three-dimensional post-stack seismic data volume of a target area, wherein the three-dimensional post-stack seismic data volume comprises a plurality of seismic records, and each seismic record comprises a plurality of sampling points; determining a sub data body of each sampling point in the three-dimensional post-stack seismic data body, wherein the sub data body of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record; for each seismic record in the subdata body of each sampling point, acquiring the frequency spectrum of the seismic record; for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of the sampling point to the frequency spectrums of other seismic records, and obtaining the difference value of the sampling point according to the ratio; and determining the earthquake fracture position according to the difference value of each sampling point. The invention can eliminate the influence of seismic wavelets and improve the accuracy of the detection of the seismic fracture position.
Description
Technical Field
The invention relates to the field of oil and gas exploration, in particular to a method and a device for detecting a seismic fracture position.
Background
In oil and gas exploration, geological data such as geological structures, sedimentary reservoirs, special geologic bodies and the like are often required to be obtained, at present, a coherent technology is a method commonly used for obtaining the geological data, a section display, a horizontal slice and a three-dimensional display can be carried out on a difference body in the geological data so as to highlight the characteristics of discontinuity, pressing continuity and the like of a seismic data body, the slice is clearer and more visual than the slice of a conventional data body, and various geological phenomena can be more clearly displayed, so that the coherent technology is widely applied to the oil and gas exploration.
Since the first proposal by Bahorich et al in 1995 of a coherent algorithm, the coherent algorithm has appeared in three generations, the first generation is a cross-correlation based coherent algorithm (abbreviated as C1 algorithm), which uses a conventional normalization algorithm to perform a cross-correlation operation between a reference trace and an adjacent trace, and calculates the difference trace by trace. The first generation of coherent algorithm has the advantages of easy realization and high calculation speed. The second generation is a coherent algorithm based on multi-channel similarity measurement (abbreviated as C2 algorithm), which was proposed by Marfurt et al in 1998, and calculates the similarity between seismic channels to obtain a difference matrix by constructing a covariance matrix. The second generation of coherent algorithm considers the dip angle and the azimuth of the stratum, enhances the anti-noise capability and the stability and can calculate the thin layer coherence. The third generation is an eigenstructure-based coherence algorithm (C3 algorithm for short) proposed by Gersztenkorn and Marfurt, which describes the coherence of seismic data by the eigenstructure of a matrix, i.e., by the eigenvalues of a covariance matrix. The third generation coherent algorithm has the advantages of high transverse resolution and strong anti-noise capability, but the calculation amount of the method is greatly increased.
When the earthquake fracture position is detected, the difference value of sampling points of a reflection interface needs to be analyzed, seismic waves and seismic wavelets have influence on the reflection interface of a stratum, a seismic data volume is obtained by convolution of the seismic waves and the reflection interface, the three generations of coherent algorithms adopt the seismic data volume for direct calculation, but the influence of the seismic wavelets is not considered, and the accuracy of detection of the earthquake fracture position is low.
Disclosure of Invention
The embodiment of the invention provides a method for detecting an earthquake fracture position, which is used for improving the accuracy of detection of the earthquake fracture position and comprises the following steps:
acquiring a three-dimensional post-stack seismic data volume of a target area, wherein the three-dimensional post-stack seismic data volume comprises a plurality of seismic records, and each seismic record comprises a plurality of sampling points;
determining a sub data body of each sampling point in the three-dimensional post-stack seismic data body, wherein the sub data body of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record;
for each seismic record in the subdata body of each sampling point, acquiring the frequency spectrum of the seismic record;
for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of the sampling point to the frequency spectrums of other seismic records, and obtaining the difference value of the sampling point according to the ratio;
and determining the earthquake fracture position according to the difference value of each sampling point.
The embodiment of the invention provides a seismic fracture position detection device, which is used for improving the accuracy of seismic fracture position detection and comprises:
the earthquake data volume acquisition module is used for acquiring a three-dimensional post-stack earthquake data volume of a target area, wherein the three-dimensional post-stack earthquake data volume comprises a plurality of earthquake records, and each earthquake record comprises a plurality of sampling points;
the sampling point data volume determining module is used for determining a sub data volume of each sampling point in the three-dimensional post-stack seismic data volume, wherein the sub data volume of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record;
the seismic record frequency spectrum obtaining module is used for obtaining the frequency spectrum of each seismic record in the subdata body of each sampling point;
the difference value calculation module is used for calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of each sampling point to the frequency spectrums of other seismic records, and obtaining the difference value of the sampling point according to the ratio;
and the earthquake fracture position determining module is used for determining the earthquake fracture position according to the difference value of each sampling point.
The embodiment of the invention also provides computer equipment which comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, wherein the processor realizes the earthquake fracture position detection method when executing the computer program.
An embodiment of the present invention further provides a computer-readable storage medium, where a computer program for executing the above-mentioned method for detecting a seismic fracture position is stored in the computer-readable storage medium.
In the embodiment of the invention, a three-dimensional post-stack seismic data volume of a target area is obtained, wherein the three-dimensional post-stack seismic data volume comprises a plurality of seismic records, and each seismic record comprises a plurality of sampling points; determining a sub data body of each sampling point in the three-dimensional post-stack seismic data body, wherein the sub data body of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record; for each seismic record in the subdata body of each sampling point, acquiring the frequency spectrum of the seismic record; for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of the sampling point to the frequency spectrums of other seismic records, obtaining the difference value of the sampling point according to the ratio, and determining the seismic fracture position according to the difference value of each sampling point. The ratio of the frequency spectrum of the central seismic record to the frequency spectrums of other seismic records can eliminate the seismic wavelet function in the frequency spectrum of the central seismic record and the frequency spectrums of other seismic records, so that the calculation precision of the difference value of each sampling point is improved, and the detection precision of the seismic fracture position is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:
FIG. 1 is a flow chart of a method of seismic fracture location detection in an embodiment of the invention;
FIG. 2 is a schematic diagram of sub-data volumes for determining sampling points in an embodiment of the present invention;
FIG. 3 is a schematic illustration of 5 seismic records selected in an embodiment of the present invention;
FIG. 4 is a spectrum corresponding to the seismic record of FIG. 3;
FIG. 5 is a stacked spectrum corresponding to the seismic record of FIG. 4;
FIG. 6 is a seismic section of a target area in an embodiment of the invention;
FIG. 7 is a schematic view of a seismic slab along the target area shown in FIG. 6;
fig. 8 is a schematic structural diagram of a seismic fracture position detection apparatus in an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.
Fig. 1 is a flowchart of a method for detecting a seismic fracture location according to an embodiment of the present invention, and as shown in fig. 1, the method includes:
103, acquiring the frequency spectrum of each seismic record in the subdata body of each sampling point;
104, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of each sampling point to the frequency spectrums of other seismic records, and obtaining the difference value of the sampling point according to the ratio;
and 105, determining the earthquake fracture position according to the difference value of each sampling point.
As can be seen from the flowchart of fig. 1, in the embodiment of the present invention, a three-dimensional post-stack seismic data volume of a target area is obtained, where the three-dimensional post-stack seismic data volume includes a plurality of seismic records, and each seismic record includes a plurality of sampling points; determining a sub data body of each sampling point in the three-dimensional post-stack seismic data body, wherein the sub data body of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record; for each seismic record in the subdata body of each sampling point, acquiring the frequency spectrum of the seismic record; for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of the sampling point to the frequency spectrums of other seismic records, obtaining the difference value of the sampling point according to the ratio, and determining the seismic fracture position according to the difference value of each sampling point. The ratio of the frequency spectrum of the central seismic record to the frequency spectrums of other seismic records can eliminate the seismic wavelet function in the frequency spectrum of the central seismic record and the frequency spectrums of other seismic records, so that the calculation precision of the difference value of each sampling point is improved, and the detection precision of the seismic fracture position is improved.
In specific implementation, a three-dimensional post-stack seismic data volume of a target area needs to be acquired, wherein the three-dimensional post-stack seismic data volume comprises a three-dimensional pre-stack seismic data volume and a three-dimensional post-stack seismic data volume, the three-dimensional post-stack seismic data volume comprises a plurality of seismic records, such as 9 seismic records, each seismic record is a continuous wave line, in order to facilitate digital storage, discrete sampling is performed on the curve, the sampling interval is 1ms or 2ms, namely, a sampling point is arranged at every 1ms or 2ms, and therefore each seismic record comprises a plurality of sampling points, such as 3 sampling points.
And then, for each sampling point in the three-dimensional post-stack seismic data volume, determining a sub data volume of the sampling point, wherein the sub data volume of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record.
In specific implementation, a two-dimensional plane window and a one-dimensional time window are adopted for each sampling point in the three-dimensional post-stack seismic data volume, and a data volume taking the sampling point as the center is obtained. The two-dimensional plane window can be a rectangle or an ellipse and the like.
In one embodiment, for each seismic record in the sub data volume of each sample point, obtaining a frequency spectrum of the seismic record may include:
stacking a window function for each seismic record in the subdata body of each sampling point;
and obtaining the frequency spectrum of the seismic record for each seismic record in the subdata body of each sampling point of the superposition window function.
In specific implementation, any one of the following window functions can be superimposed on each seismic record in the sub data body of each sampling point to reduce the leakage of spectral energy.
Gaussian window (Gauss window), Hamming window (Hamming window), or Hanning window (Hanning window).
The gaussian window function can be expressed as:
wherein a is a constant and determines the attenuation speed of the function curve;
m is a discrete moment;
m is the length of the Gaussian window, the length value M is equal to L, and L is the length of the time window.
The hamming window function can be expressed as:
wherein m is a discrete time;
m is the length of the Hamming window, the length value of M is L-1, and L is the length of the time window.
The Hanning window function can be expressed as:
wherein m is a discrete time;
m is the length of the Hanning window, the length value is M-L-1, and L is the length of the time window.
Of course, it should be understood that the gaussian window, hamming window or hanning window is used as an example, and other window functions may be used to stack each seismic record in the sub data volume of each sampling point, and the related variations are all within the protection scope of the present invention.
In specific implementation, fourier transform can be performed on each seismic record in the sub data volume of each sampling point of the superimposed window function, so as to obtain the frequency spectrum of the seismic record.
In an embodiment, before calculating, for each sampling point, a ratio of a frequency spectrum of a central seismic record in the sub data volume of the sampling point to frequency spectrums of other seismic records, and obtaining a difference value of the sampling point according to the ratio, the method may further include:
and determining the effective frequency band of the three-dimensional post-stack seismic data volume.
In one embodiment, determining the effective frequency band of the three-dimensional post-stack seismic data volume may include:
selecting a plurality of seismic records from the three-dimensional post-stack seismic data volume;
for each selected seismic record, obtaining the frequency spectrum of the seismic record;
stacking the frequency spectrums of the multiple seismic records to obtain stacked frequency spectrums of the multiple seismic records;
and determining the effective frequency band according to the preset starting frequency, the preset terminating frequency, the preset amplitude threshold value and the superposed frequency spectrum.
In specific implementation, a plurality of discrete seismic records far away from the boundary can be randomly selected from the three-dimensional post-stack seismic data volume;
in one embodiment, for each selected seismic record, a fourier transform method may be used to perform spectral analysis to obtain a frequency spectrum of the seismic record, and then, the frequency spectrums of the multiple seismic records are stacked to obtain a stacked frequency spectrum of the multiple seismic records.
In an embodiment, determining the effective frequency band according to the preset start frequency, the preset end frequency, the preset amplitude threshold and the superimposed spectrum may include:
determining a first amplitude value larger than a preset amplitude threshold value in the superposed frequency spectrum along a preset starting frequency to a high frequency direction, and determining a frequency value corresponding to the amplitude value as the minimum frequency of the effective frequency band;
and determining the first amplitude value which is larger than a preset amplitude threshold value in the superposed frequency spectrum along the direction from the preset termination frequency to the low frequency, and determining the frequency value corresponding to the amplitude value as the maximum frequency of the effective frequency band.
In specific implementation, the preset starting frequency is 5Hz, the preset terminating frequency is 100Hz, and the preset amplitude threshold value can be obtained by the following method:
searching the maximum amplitude value in the range from a preset starting frequency to a preset ending frequency in the superposed frequency spectrum;
and multiplying the maximum amplitude value by a certain coefficient (the coefficient range is 0.0-1.0) to obtain a preset amplitude threshold value.
In an embodiment, for each sampling point, calculating a ratio of a frequency spectrum of a central seismic record in the sub data volume of the sampling point to frequency spectrums of other seismic records, and obtaining a difference value of the sampling point according to the ratio may include:
calculating the frequency spectrum of the seismic record in the sub data body of each sampling point in the effective frequency band;
for each sampling point, calculating the ratio of the frequency spectrum of the central earthquake record in the effective frequency band in the sub data body of the sampling point to the frequency spectrum of other earthquake records in the effective frequency band, and obtaining the difference value of the sampling point according to the ratio.
In one embodiment, calculating the spectrum of the seismic records in the sub data volume of each sampling point within the effective frequency band may include:
according to the effective frequency band, for each seismic record in the subdata body of each sampling point, determining the frequency spectrum of the seismic record in the effective frequency band by adopting the following formula:
Aj(x,y,t)＝(aj1,aj2,…,ajn)；j＝1,2,…,J；n＝1,2,…,N
wherein A isj(x, y, t) is the frequency spectrum of the jth seismic record in the sub data body of each sampling point in the effective frequency band;
ajnrecording the frequency spectrum of the nth data in the effective frequency band for the jth earthquake in the subdata body of each sampling point;
n is the number of the data of the jth seismic record in the sub data body of each sampling point in the effective frequency band;
j is the number of seismic records in the subdata body of each sampling point.
In an embodiment, for each sampling point, calculating a ratio of a frequency spectrum of a central seismic record in an effective frequency band to frequency spectrums of other seismic records in the effective frequency band in sub data volumes of the sampling point, and obtaining a difference value of the sampling point according to the ratio may include:
for each sampling point, calculating the ratio of the frequency spectrum of the central earthquake record in the effective frequency band in the sub data body of the sampling point to the frequency spectrum of other earthquake records in the effective frequency band by adopting the following formula:
wherein, ajnRecording the frequency spectrum of the nth data in the effective frequency band for the jth earthquake in the subdata body of each sampling point;
acnrecording the frequency spectrum of the nth data in the effective frequency band for the central earthquake in the subdata body of each sampling point;
djnthe ratio of the frequency spectrum of the nth data of the jth seismic record and the central seismic record in the effective frequency band in the subdata body of each sampling point is obtained;
according to the ratio, the difference value of the sampling points is obtained by adopting the following formula:
wherein d (x, y, t) is the difference value of each sampling point;
n is the number of the data of the jth seismic record in the sub data body of each sampling point in the effective frequency band;
j is the number of seismic records in the subdata body of each sampling point.
The seismic record can be regarded as convolution of wavelet function and reflection coefficient sequence, and the seismic wavelet function is assumed to be s (t), and the two reflection coefficient sequences are respectively r1(t) and r2(t), then two seismic records f can be obtained1(t)＝s(t)*r1(t) and f2(t)＝s(t)*r2(t); and respectively carrying out time-frequency transformation on the two seismic records to obtain frequency spectrums of the two seismic records, and obtaining: f1(ω)＝S(ω)·R1(omega) and F2(ω)＝S(ω)·R2(ω), calculating the ratio of the two seismic recording spectra:
it can be seen that the ratio of the two seismic record frequency spectrums does not contain the frequency spectrum of the seismic wavelet function, so that the method for detecting the seismic fracture position provided by the embodiment of the invention obtains the difference value of the sampling point by calculating the ratio of the frequency spectrum of the central seismic record in the effective frequency band in the sub data body of the sampling point to the frequency spectrum of other seismic records in the effective frequency band according to the ratio, namely, eliminating the influence of the seismic wavelet on the difference value of the sampling point, and determining the seismic fracture position through the difference value of each sampling point, thereby improving the accuracy of detecting the seismic fracture position.
A specific example is given below to illustrate a specific application of the method for detecting a seismic fracture location according to the present invention.
The method comprises the steps of firstly obtaining a three-dimensional post-stack seismic data volume of a target area, and then determining a sub data volume of each sampling point in the three-dimensional post-stack seismic data volume. Fig. 2 is a schematic diagram of a sub-data volume for determining a sampling point in the implementation of the present invention, and as shown in fig. 2, a data volume with a sampling point a as a center is obtained by using a two-dimensional planar window and a one-dimensional time window, where the two-dimensional planar window is a square, the one-dimensional time window is 50 milliseconds, the data volume includes 9 seismic records and 25 sampling points, and the seismic record with the sampling point a is the central seismic record;
and (3) zero padding the tail part of the seismic record of the sampling point A, stacking the Gaussian window function, and then obtaining the frequency spectrum of the seismic record by adopting a Fourier transform method for each seismic record in the subdata body of each sampling point of the stacked Gaussian window function, wherein the number NFFT of the calculation points of the Fourier transform is 64.
In this embodiment, an effective frequency band of a three-dimensional post-stack seismic data volume needs to be determined, 5 seismic records which are as discrete as possible and far from a boundary are randomly selected from the three-dimensional post-stack seismic data volume, and fig. 3 is a schematic diagram of the 5 seismic records selected in the embodiment of the present invention, where the number of sampling points of the three-dimensional post-stack seismic data volume is 1001, the sampling interval is 2 milliseconds, and the number of calculation points NFFT of fourier transform is 1024.
Fig. 4 is a frequency spectrum corresponding to the seismic record in fig. 3, in this embodiment, a fourier transform is used to obtain a frequency spectrum of 5 seismic records, and then the frequency spectrums of the above 5 seismic records are stacked to obtain a stacked frequency spectrum of the 5 seismic records, and fig. 5 is a stacked frequency spectrum corresponding to the seismic record in fig. 4.
Determining an effective frequency band according to a preset starting frequency, a preset terminating frequency, a preset amplitude threshold and a superposed frequency spectrum, wherein the preset starting frequency is 5Hz, the preset terminating frequency is 100Hz, searching a maximum amplitude value in a range from the preset starting frequency to the preset terminating frequency in the superposed frequency spectrum, and multiplying the maximum amplitude value by a coefficient of 0.08 to obtain the preset amplitude threshold.
Then, determining an amplitude value of which the first amplitude value is larger than a preset amplitude threshold value in the superposed frequency spectrum along a preset starting frequency to a high frequency direction, and determining a frequency value corresponding to the amplitude value as the minimum frequency of the effective frequency band; and determining the first amplitude value larger than a preset amplitude threshold value in the superposed frequency spectrum along the direction of the preset termination frequency to the low frequency, determining the frequency value corresponding to the amplitude value as the maximum frequency of the effective frequency band, and finally determining the effective frequency band to be 4.8 Hz-62.5 Hz.
In this embodiment, according to the effective frequency band of 4.8Hz to 62.5Hz, for each of 9 seismic records in the data volume of the sampling point a, the following formula is adopted to determine the frequency spectrum of the seismic record in the effective frequency band:
Aj(x,y,t)＝(aj1,aj2,…,ajn)；j＝1,2,…,J；n＝1,2,…,N
wherein A isj(x, y, t) is the frequency spectrum of the jth seismic record in the data body of the sampling point A in the effective frequency band;
ajnrecording the frequency spectrum of the nth data in the effective frequency band for the jth earthquake in the data body of the sampling point A;
n is the number of data of the jth seismic record in the effective frequency band in the data volume of the sampling point a, and in this embodiment, N is 25;
j is the number of seismic records in the data volume of sample point a, and in the present embodiment, J is 9.
In the above 9 seismic records, the central seismic record is the 5 th seismic record, and the frequency spectrum of the central seismic record in a segmented frequency band is:
A5(x,y,t)＝(a51,a52,…,a5n)；n＝1,2,…,N
wherein, a5nRecording the frequency spectrum of the nth data in the effective frequency band for the central earthquake;
n is the number of data recorded in the effective frequency band by the central seismic, and in this embodiment, N is 25.
For the sampling point A, the ratio of the frequency spectrum of the central earthquake record in the effective frequency band in the sub data body of the sampling point to the frequency spectrum of other earthquake records in the effective frequency band is calculated by adopting the following formula:
wherein, ajnRecording the frequency spectrum of the nth data in the effective frequency band for the jth earthquake in the data body of the sampling point A;
djnthe ratio of the frequency spectrum of the jth seismic record in the data volume of the sampling point A and the frequency spectrum of the nth data of the central seismic record in the effective frequency band is obtained;
according to the ratio, the difference value of the sampling points is obtained by adopting the following formula:
wherein d (x, y, t) is the difference value of the sampling point A;
n is the number of data of the jth seismic record in the effective frequency band in the data volume of the sampling point a, and in this embodiment, N is 25;
j is the number of seismic records in the data volume of sample point a, and in the present embodiment, J is 9.
And obtaining the difference value of each sampling point in the three-dimensional post-stack seismic data body by using the difference value obtaining method of the sampling point A.
Determining the seismic fracture position according to the difference value of each sampling point, wherein fig. 6 is a seismic section of a target area in the embodiment of the invention, fig. 7 is a schematic diagram of a seismic section along a layer of the target area shown in fig. 6, as shown in fig. 6 and fig. 7, three fracture positions can be seen, wherein the fracture positions are the boundaries of concentric annular faults at positions A1 and A2, and B1 is a fault.
In the embodiment of the invention, a three-dimensional post-stack seismic data volume of a target area is obtained, wherein the three-dimensional post-stack seismic data volume comprises a plurality of seismic records, and each seismic record comprises a plurality of sampling points; determining a sub data body of each sampling point in the three-dimensional post-stack seismic data body, wherein the sub data body of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record; for each seismic record in the subdata body of each sampling point, acquiring the frequency spectrum of the seismic record; for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of the sampling point to the frequency spectrums of other seismic records, obtaining the difference value of the sampling point according to the ratio, and determining the seismic fracture position according to the difference value of each sampling point. The ratio of the frequency spectrum of the central seismic record to the frequency spectrums of other seismic records can eliminate the seismic wavelet function in the frequency spectrum of the central seismic record and the frequency spectrums of other seismic records, so that the calculation precision of the difference value of each sampling point is improved, and the detection precision of the seismic fracture position is improved.
Based on the same inventive concept, the embodiment of the present invention further provides a seismic fracture position detection apparatus, as described in the following embodiments. Because the principle of solving the problems of the system is similar to the method for detecting the earthquake fracture position, the implementation of the system can refer to the implementation of the method, and repeated details are not repeated.
Fig. 8 is a schematic structural diagram of an earthquake fracture position detection apparatus in an embodiment of the present invention, and as shown in fig. 8, the apparatus includes:
a seismic data volume obtaining module 801, configured to obtain a three-dimensional post-stack seismic data volume of a target area, where the three-dimensional post-stack seismic data volume includes multiple seismic records, and each seismic record includes multiple sampling points;
a sampling point data volume determining module 802, configured to determine, for each sampling point in the three-dimensional post-stack seismic data volume, a sub-data volume of the sampling point, where the sub-data volume of the sampling point includes multiple seismic records that take the seismic record where the sampling point is located as a central seismic record;
a seismic record spectrum obtaining module 803, configured to obtain a spectrum of each seismic record in the sub data volume of each sampling point;
a difference value calculating module 804, configured to calculate, for each sampling point, a ratio of a frequency spectrum of a central seismic record in the sub data volume of the sampling point to frequency spectrums of other seismic records, and obtain a difference value of the sampling point according to the ratio;
and a seismic fracture position determining module 805, configured to determine a seismic fracture position according to the difference value of each sampling point.
In one embodiment, the seismic recording spectrum acquisition module 803 may be specifically configured to:
for each seismic record in the data volume for each sample point, stacking a window function:
for each seismic record in the data volume for each sample point of the superimposed window function, the frequency spectrum for that seismic record is obtained.
In an embodiment, the apparatus for detecting a seismic fracture position may further include:
an effective frequency band determination module 806, configured to determine an effective frequency band of the three-dimensional post-stack seismic data volume;
the difference value calculating module may be further configured to:
calculating the frequency spectrum of the seismic record in the data body of each sampling point in the effective frequency band;
for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the effective frequency band of the data body of the sampling point to the frequency spectrum of other seismic records in the effective frequency band, and obtaining the difference value of the sampling point according to the ratio.
In an embodiment, the effective frequency band determining module 806 may be specifically configured to:
selecting a plurality of seismic records from the three-dimensional post-stack seismic data volume;
for each selected seismic record, obtaining the frequency spectrum of the seismic record;
stacking the frequency spectrums of the multiple seismic records to obtain stacked frequency spectrums of the multiple seismic records;
and determining the effective frequency band according to the preset starting frequency, the preset terminating frequency, the preset amplitude threshold value and the superposed frequency spectrum.
In summary, in the embodiment of the present invention, a three-dimensional post-stack seismic data volume of a target area is obtained, where the three-dimensional post-stack seismic data volume includes multiple seismic records, and each seismic record includes multiple sampling points; determining a sub data body of each sampling point in the three-dimensional post-stack seismic data body, wherein the sub data body of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record; for each seismic record in the subdata body of each sampling point, acquiring the frequency spectrum of the seismic record; for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of the sampling point to the frequency spectrums of other seismic records, obtaining the difference value of the sampling point according to the ratio, and determining the seismic fracture position according to the difference value of each sampling point. The ratio of the frequency spectrum of the central seismic record to the frequency spectrums of other seismic records can eliminate the seismic wavelet function in the frequency spectrum of the central seismic record and the frequency spectrums of other seismic records, so that the calculation precision of the difference value of each sampling point is improved, and the detection precision of the seismic fracture position is improved.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (13)
1. A seismic break location detection method, comprising:
acquiring a three-dimensional post-stack seismic data volume of a target area, wherein the three-dimensional post-stack seismic data volume comprises a plurality of seismic records, and each seismic record comprises a plurality of sampling points;
determining a sub data body of each sampling point in the three-dimensional post-stack seismic data body, wherein the sub data body of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record;
for each seismic record in the subdata body of each sampling point, acquiring the frequency spectrum of the seismic record;
for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of the sampling point to the frequency spectrums of other seismic records, and obtaining the difference value of the sampling point according to the ratio;
determining the earthquake fracture position according to the difference value of each sampling point;
wherein, according to the ratio, the difference value of the sampling point is obtained by adopting the following formula:
wherein d (x, y, t) is the difference value of each sampling point;
n is the number of the data of the jth seismic record in the sub data body of each sampling point in the effective frequency band;
j is the number of seismic records in the subdata body of each sampling point.
2. The method of detecting a seismic break location of claim 1, wherein obtaining a frequency spectrum of each seismic record in the sub data volume for each sample point comprises:
stacking a window function for each seismic record in the subdata body of each sampling point;
and obtaining the frequency spectrum of the seismic record for each seismic record in the subdata body of each sampling point of the superposition window function.
3. The method for detecting the earthquake fracture position according to claim 1, wherein before calculating the ratio of the frequency spectrum of the central earthquake record to the frequency spectrums of other earthquake records in the sub data body of each sampling point, and obtaining the difference value of the sampling point according to the ratio, the method further comprises:
determining an effective frequency band of the three-dimensional post-stack seismic data volume;
for each sampling point, calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of the sampling point to the frequency spectrums of other seismic records, and obtaining the difference value of the sampling point according to the ratio, wherein the difference value comprises the following steps:
calculating the frequency spectrum of the seismic record in the sub data body of each sampling point in the effective frequency band;
for each sampling point, calculating the ratio of the frequency spectrum of the central earthquake record in the effective frequency band in the sub data body of the sampling point to the frequency spectrum of other earthquake records in the effective frequency band, and obtaining the difference value of the sampling point according to the ratio.
4. The method of seismic fracture location detection according to claim 3, wherein determining the effective frequency band of the three-dimensional post-stack seismic data volume comprises:
selecting a plurality of seismic records from the three-dimensional post-stack seismic data volume;
for each selected seismic record, obtaining the frequency spectrum of the seismic record;
stacking the frequency spectrums of the multiple seismic records to obtain stacked frequency spectrums of the multiple seismic records;
and determining the effective frequency band according to the preset starting frequency, the preset terminating frequency, the preset amplitude threshold value and the superposed frequency spectrum.
5. The method of detecting seismic break locations according to claim 4, wherein determining an effective frequency band based on a preset start frequency, a preset stop frequency, a preset amplitude threshold and a superposition spectrum comprises:
determining a first amplitude value larger than a preset amplitude threshold value in the superposed frequency spectrum along a preset starting frequency to a high frequency direction, and determining a frequency value corresponding to the amplitude value as the minimum frequency of the effective frequency band;
and determining the first amplitude value which is larger than a preset amplitude threshold value in the superposed frequency spectrum along the direction from the preset termination frequency to the low frequency, and determining the frequency value corresponding to the amplitude value as the maximum frequency of the effective frequency band.
6. The method of detecting a seismic break location according to claim 3, wherein calculating a spectrum of seismic records in the sub data volume of each sample point within an effective frequency band comprises:
according to the effective frequency band, for each seismic record in the subdata body of each sampling point, determining the frequency spectrum of the seismic record in the effective frequency band by adopting the following formula:
Aj(x,y,t)＝(aj1,aj2,…,ajn)；j＝1,2,…,J；n＝1,2,…,N
wherein A isj(x, y, t) is the frequency spectrum of the jth seismic record in the sub data body of each sampling point in the effective frequency band;
ajnrecording the frequency spectrum of the nth data in the effective frequency band for the jth earthquake in the subdata body of each sampling point;
n is the number of the data of the jth seismic record in the sub data body of each sampling point in the effective frequency band;
j is the number of seismic records in the subdata body of each sampling point.
7. The method for detecting the earthquake fracture position according to claim 3, wherein for each sampling point, the ratio of the frequency spectrum of the central earthquake record in the effective frequency band in the sub data body of the sampling point to the frequency spectrum of other earthquake records in the effective frequency band is calculated, and the difference value of the sampling point is obtained according to the ratio, and the method comprises the following steps:
for each sampling point, calculating the ratio of the frequency spectrum of the central earthquake record in the effective frequency band in the sub data body of the sampling point to the frequency spectrum of other earthquake records in the effective frequency band by adopting the following formula:
wherein, ajnRecording the frequency spectrum of the nth data in the effective frequency band for the jth earthquake in the subdata body of each sampling point;
acnrecording the frequency spectrum of the nth data in the effective frequency band for the central earthquake in the subdata body of each sampling point;
djnand the ratio of the frequency spectrum of the jth seismic record in the sub data body of each sampling point to the frequency spectrum of the nth data of the central seismic record in the effective frequency band is obtained.
8. A seismic break location detection device, comprising:
the earthquake data volume acquisition module is used for acquiring a three-dimensional post-stack earthquake data volume of a target area, wherein the three-dimensional post-stack earthquake data volume comprises a plurality of earthquake records, and each earthquake record comprises a plurality of sampling points;
the sampling point data volume determining module is used for determining a sub data volume of each sampling point in the three-dimensional post-stack seismic data volume, wherein the sub data volume of the sampling point comprises a plurality of seismic records taking the seismic record where the sampling point is as a center seismic record;
the seismic record frequency spectrum obtaining module is used for obtaining the frequency spectrum of each seismic record in the subdata body of each sampling point;
the difference value calculation module is used for calculating the ratio of the frequency spectrum of the central seismic record in the sub data body of each sampling point to the frequency spectrums of other seismic records, and obtaining the difference value of the sampling point according to the ratio;
the earthquake fracture position determining module is used for determining the earthquake fracture position according to the difference value of each sampling point;
the difference value calculation module is specifically configured to:
according to the ratio, the difference value of the sampling points is obtained by adopting the following formula:
wherein d (x, y, t) is the difference value of each sampling point;
n is the number of the data of the jth seismic record in the sub data body of each sampling point in the effective frequency band;
j is the number of seismic records in the subdata body of each sampling point.
9. The seismic break location detection apparatus of claim 8, wherein the seismic recording spectrum acquisition module is specifically configured to:
and for each seismic record in the subdata body of each sampling point, stacking a window function:
and obtaining the frequency spectrum of the seismic record for each seismic record in the subdata body of each sampling point of the superposition window function.
10. The seismic break location detection apparatus of claim 8, further comprising:
the effective frequency band determining module is used for determining the effective frequency band of the three-dimensional post-stack seismic data volume;
the difference value calculation module is further configured to:
calculating the frequency spectrum of the seismic record in the sub data body of each sampling point in the effective frequency band;
for each sampling point, calculating the ratio of the frequency spectrum of the central earthquake record in the effective frequency band in the sub data body of the sampling point to the frequency spectrum of other earthquake records in the effective frequency band, and obtaining the difference value of the sampling point according to the ratio.
11. The seismic break location detection device of claim 10, wherein the active frequency band determination module is specifically configured to:
selecting a plurality of seismic records from the three-dimensional post-stack seismic data volume;
for each selected seismic record, obtaining the frequency spectrum of the seismic record;
stacking the frequency spectrums of the multiple seismic records to obtain stacked frequency spectrums of the multiple seismic records;
and determining the effective frequency band according to the preset starting frequency, the preset terminating frequency, the preset amplitude threshold value and the superposed frequency spectrum.
12. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the method of any one of claims 1 to 7 when executing the computer program.
13. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for executing the method of any one of claims 1 to 7.
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