CN115327622A - Imaging-oriented seismic data construction method - Google Patents

Abstract

The invention provides an imaging-oriented seismic data construction method, which comprises the following steps: step 1: designing a target observation system according to the imaging requirement of the underground geological target; step 2: transforming field-acquired seismic data from a time domain to a frequency domain; and step 3: transforming the frequency domain seismic data to a frequency wavenumber domain; and 4, step 4: obtaining a Fourier coefficient with the maximum frequency amplitude value for each frequency; and 5: obtaining an optimal reconstruction coefficient; step 6: and performing Fourier inverse transformation by using the optimal reconstruction coefficient to obtain the optimized construction seismic data which accord with the target observation system. The imaging-oriented seismic data construction method can well compensate the problems of seismic data loss, insufficient coverage times and the like caused by field acquisition and observation, improve the quality of seismic data, obtain optimized seismic data and improve the seismic imaging quality.

Description

Imaging-Oriented Seismic Data Construction Method

technical field

The invention relates to the field of oil and gas exploration seismic data processing, in particular to an imaging-oriented seismic data construction method.

Background technique

With the continuous deepening of oil and gas exploration and development, the types of oil and gas reservoirs gradually shift to complex and subtle oil and gas reservoirs, which put forward higher resolution and higher fidelity requirements for seismic technology. In this case, single-point high-density seismic technology Emerged as the times require, single-point reception, wide azimuth, and high shot density are required. This technology has been widely used in eastern China, improving imaging resolution and fidelity. However, favorable exploration areas are affected by surface obstacles, construction cannot be carried out in prohibited mining areas, and excitation and reception are restricted in restricted mining areas, resulting in a large number of gaps in seismic data, insufficient illumination of geological targets, and affecting imaging quality. At present, one of the conventional solutions is to use mathematical transformation-based algorithms to regularize seismic data or data interpolation, and then perform stacked imaging. This method does not consider the underground lighting of geological targets, and the improvement effect on missing seismic data imaging is not good. obvious. The other is to combine old data and then superimpose imaging, but due to differences in frequency, amplitude, phase, and time difference of old data, the consistency is poor, and the stitching effect is not ideal, so it is difficult to meet the needs of fine exploration.

In the Chinese patent application with application number: CN201510346548.6, it relates to a method of constructing a velocity model of seismic data, including: (A) obtaining the initial velocity model of seismic data; (B) using the initial velocity model to perform survey line (C) Obtain each reference velocity model with the initial velocity model under at least one percentage velocity factor; (D) Use each reference velocity model to obtain the common reflection point gather; (E) Collect the total The reflection point gathers are superimposed into multi-channel mini-profiles of velocity analysis points; (F) for each layer, the optimal mini-profile is determined, and the velocity of the velocity analysis point in the reference velocity model under the percentage velocity factor corresponding to the optimal mini-profile As the optimal migration velocity of the velocity analysis point in the corresponding horizon; (G) replace the corresponding velocity of each velocity analysis point in the original velocity model with the optimal migration velocity of each velocity analysis point in each horizon.

In the Chinese patent application with application number: CN202011229691.4, it involves a VIA dual-parameter imaging method for seismic data processing, including: arranging the seismic data acquisition and observation system, including setting the positions of shot points and receiver points and the arrangement relationship between them , use the seismic data acquisition and observation system to collect seismic data, and set the relevant parameters of seismic wave propagation; calculate the transformation equation of the VIA dual-parameter imaging method; through the above transformation equation, convert t to t0 to realize seismic data imaging.

In the Chinese patent application with application number: CN201410049621.9, it relates to a method and system for reverse time migration imaging applied to land seismic data. The method includes: collecting land seismic data; performing strong denoising processing on the land seismic data to obtain strong denoising data; performing weak denoising processing on the land seismic data to obtain weak denoising data; constructing broadband wavelets according to the land seismic data; Constructing a velocity model from the strong denoising data; performing reverse time migration imaging according to the weak denoising data, broadband wavelet, and velocity model to obtain an initial reverse time migration imaging result; The low-frequency noise attenuation is performed on the migration imaging results to obtain the reverse time migration imaging results.

The above existing technologies are quite different from the present invention, and cannot solve the technical problems we want to solve. Therefore, we have invented a new imaging-oriented seismic data construction method.

Contents of the invention

The purpose of the present invention is to provide an imaging-oriented seismic data construction method aiming at improving the imaging quality and compensating the quality reduction of seismic data caused by the acquisition variation of the surface obstacle area.

The object of the present invention can be achieved through the following technical measures: an imaging-oriented seismic data construction method, the imaging-oriented seismic data construction method comprising:

Step 1: Design the target observation system according to the imaging requirements of underground geological targets;

Step 2: Transform the seismic data collected in the field from the time domain to the frequency domain;

Step 3: Transform the seismic data in the frequency domain to the frequency wavenumber domain;

Step 4: Find the Fourier coefficient with the largest frequency amplitude value for each frequency;

Step 5: Obtain the optimal reconstruction coefficient;

Step 6: Inverse Fourier transform is performed using the optimal reconstruction coefficient to obtain the optimally constructed seismic data in line with the target observation system.

The purpose of the present invention can also be achieved through the following technical measures:

In step 1, the seismic data collected in the field is denoted as D, and the corresponding observation system is denoted as S; according to the imaging requirements of underground geological targets and considering the illumination of underground geological bodies, the target observation system M is designed.

In step 2, the seismic data D collected in the field is input, and Fourier transform is performed on each seismic trace to change the time domain data (t, x, y) into frequency domain data (f, x, y), where t represents Time, x and y represent the horizontal and vertical coordinates of the space, and f represents the frequency.

In step 3, two-dimensional discrete Fourier transform is performed on the frequency domain data (f, x, y) and converted into the frequency wavenumber domain (f, kx, ky), where kx and ky represent the correspondence between the x direction and the y direction wave number.

In step 4, the Fourier coefficient with the largest amplitude value of each frequency is obtained, and after the coefficient is inversely transformed back to the time domain, it is subtracted from the seismic data until the calculation of all frequencies is completed.

In step 4, for each frequency f, the Fourier coefficient with the largest amplitude value is selected as (kx, ky) _max , and after inverse transformation back to the time domain, it is subtracted from the collected seismic data; each frequency f All operate in this way.

In step 4, the frequency f is selected from 0 to 60 Hz.

In step 4, the frequency f is selected from 0 to 65 Hz.

In step 5, step 4 is repeated until the error is smaller than the set threshold, and the optimal reconstruction coefficient is obtained.

In step 6, using the optimal reconstruction coefficient and taking the target observation system M as the scale, inverse Fourier transform is performed to obtain the imaging optimally constructed seismic data R at the positions of each seismic source and receiving point in the target observation system M.

In the imaging-oriented seismic data construction method of the present invention, the target observation system is designed according to the imaging illumination of the underground geological body, the wave field construction of the seismic data is guided, the illumination degree of the surface obstacle area is compensated, and the imaging quality is improved. Compared with the prior art, the imaging-oriented seismic data construction method of the present invention has the following advantages:

First, the frequency, phase, and amplitude of the seismic data obtained by the invention have strong consistency, which can better compensate for the lack of seismic data and insufficient coverage times caused by field acquisition changes, and improve the quality of seismic data.

Second, the invention fully considers the imaging lighting of underground geological bodies, and designs a target observation system that is conducive to imaging, which can obtain optimized seismic data and improve the quality of seismic imaging.

Description of drawings

Fig. 1 is the flowchart of a specific embodiment of the imaging-oriented seismic data construction method of the present invention;

Fig. 2 is a schematic diagram of the actual position of the field acquisition shot point in a specific embodiment of the present invention;

Fig. 3 is a schematic diagram of a shot point target observation system set according to imaging requirements in a specific embodiment of the present invention;

Fig. 4 is a schematic diagram of a single-shot seismic record obtained by imaging optimization construction in a specific embodiment of the present invention;

Fig. 5 is a schematic diagram of a superposition section of imaging optimization construction data in a specific embodiment of the present invention;

Fig. 6 is a schematic diagram of a stacked profile of conventional method reconstruction data in a specific embodiment of the present invention;

Fig. 7 is a schematic diagram of the actual position of the shot point collected in the field in a specific embodiment of the present invention;

8 is a schematic diagram of a shot point target observation system set according to imaging requirements in a specific embodiment of the present invention;

Fig. 9 is a schematic diagram of a seismic single-shot record obtained by imaging optimization construction in a specific embodiment of the present invention;

Fig. 10 is a schematic diagram of a migration profile of imaging optimization construction data in a specific embodiment of the present invention;

FIG. 11 is a schematic diagram of a migration profile of data reconstructed by a conventional method in an embodiment of the present invention.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used here is only for describing specific embodiments, and is not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations and/or combinations thereof.

The imaging-oriented seismic data construction method of the present invention includes the following steps:

(1) According to the imaging requirements of underground geological targets, consider the lighting of underground geological bodies, and design the target observation system;

(2) Transform the seismic data collected in the field from the time domain to the frequency domain;

(3) Transform the seismic data in the frequency domain to the frequency wavenumber domain;

(4) Find the Fourier coefficient with the largest amplitude value for each frequency, and after inversely transforming this coefficient back to the time domain, subtract it from the collected seismic data until the calculation of all frequencies is completed;

(5) Repeat step 4 until the error is less than the set threshold, and obtain the optimal reconstruction coefficient;

(6) Inverse Fourier transform is performed by using the optimal reconstruction coefficient to obtain the seismic data constructed by imaging optimization conforming to the target observation system.

In a specific embodiment 1 of the application of the present invention, the imaging-oriented seismic data construction method of the present invention specifically includes the following steps:

(1) The seismic data collected in the field is marked as D, and the corresponding observation system is marked as S. According to the imaging requirements of underground geological targets, the target observation system M is designed considering the illumination of underground geological bodies.

(2) Input the seismic data D collected in the field, and perform Fourier transform on each seismic trace to change the time domain data (t, x, y) into frequency domain data (f, x, y), where t represents time, x and y represent the horizontal and vertical coordinates of the space, and f represents the frequency.

(3) Do a two-dimensional discrete Fourier transform on the frequency domain data (f, x, y) and convert it to the frequency wavenumber domain (f, kx, ky), where kx and ky represent the corresponding wavenumbers in the x direction and y direction .

(4) For each frequency f, select the Fourier coefficient with the largest amplitude value as (kx, ky) _max , inversely transform it back to the time domain, and subtract it from the collected seismic data; each frequency f is calculated according to This method operates.

(5) Repeat step 4 until the error is smaller than the set threshold, and obtain the optimal reconstruction coefficient.

(6) Using the optimal reconstruction coefficient and taking the target observation system M as the scale plate, inverse Fourier transform is performed to obtain the imaging optimal construction seismic data R at the positions of each source and receiver point in the target observation system M.

In a specific embodiment 2 of the present invention, as shown in FIG. 1 , FIG. 1 shows the operation steps of the imaging-oriented seismic data construction method.

In step 101, the actual observation system is collected in the field. Due to the influence of surface obstacles, the shot point of the observation system S is seriously missing (Fig. 2). According to the lighting requirements of geological bodies, the target observation system M for the shot point is set (Fig. 3). .

Step 102, input the seismic data D collected in the field, and perform Fourier transform on each seismic track to change the time domain data (t, x, y) into frequency domain data (f, x, y), where t represents time, x and y represent the horizontal and vertical coordinates of the space, and f represents the frequency.

Step 103, perform a two-dimensional discrete Fourier transform on the frequency domain data (f, x, y), and convert it into a frequency wavenumber domain (f, kx, ky), where kx and ky represent the wavenumbers corresponding to the x direction and the y direction .

Step 104, for each frequency f, select the Fourier coefficient with the largest amplitude value as (kx, ky) _max , inversely transform it back to the time domain, and subtract it from the collected seismic data. Each frequency f is calculated according to This method operates, and the frequency f here is selected from 0 to 60 Hz.

In step 105, step 4 is repeated until the error is smaller than the set threshold, and the optimal reconstruction coefficient is obtained.

Step 106, using the optimal reconstruction coefficient, taking the target observation system M as the scale, and performing inverse Fourier transform to obtain the imaging optimally constructed seismic data R at the positions of each seismic source and receiving point in the target observation system M (Fig. 4) .

In order to illustrate the advantages of the imaging-oriented seismic data construction method, the seismic data D of the field acquisition observation system S is reconstructed using conventional methods, and the seismic data R obtained by applying the target observation system M designed by the present invention to optimize the construction are respectively carried out. Superposition, it can be found that the superposition result of the optimally constructed seismic data ( FIG. 5 ) of the present invention is better than the superposition result ( FIG. 6 ) of reconstructed data by the conventional method, which verifies the practical effect of the present invention.

In a specific embodiment 3 of the application of the present invention, the imaging-oriented seismic data construction method of the present invention specifically includes the following steps:

In step 101, the actual observation system is collected in the field. Due to the influence of surface obstacles, the shot points of the observation system S are seriously missing (Fig. 7). According to the illumination requirements of geological bodies, the target observation system M of the shot points is set (Fig. 8).

Step 102, input the seismic data D collected in the field, and perform Fourier transform on each seismic track to change the time domain data (t, x, y) into frequency domain data (f, x, y), where t represents time, x and y represent the horizontal and vertical coordinates of the space, and f represents the frequency.

Step 103, perform a two-dimensional discrete Fourier transform on the frequency domain data (f, x, y), and convert it into a frequency wavenumber domain (f, kx, ky), where kx and ky represent the wavenumbers corresponding to the x direction and the y direction .

Step 104, for each frequency f, select the Fourier coefficient with the largest amplitude value as (kx, ky) _max , inversely transform it back to the time domain, and subtract it from the collected seismic data. Each frequency f is calculated according to This method operates, and the frequency f here is selected from 0 to 65Hz.

In step 105, step 4 is repeated until the error is smaller than the set threshold, and the optimal reconstruction coefficient is obtained.

Step 106, using the optimal reconstruction coefficient, taking the target observation system M as the scale, and performing inverse Fourier transform to obtain the imaging optimally constructed seismic data R at the positions of each seismic source and receiving point in the target observation system M (Fig. 9) .

In order to illustrate the advantages of the imaging-oriented seismic data construction method, the seismic data D of the field acquisition observation system S is reconstructed using conventional methods, and the seismic data R obtained by applying the target observation system M designed by the present invention to optimize the construction are respectively carried out. Pre-stack time migration, it can be found that the migration result (Fig. 10) of the present invention is better than the migration result (Fig. 11) of reconstructed data by the conventional method, which proves that the present invention improves the imaging quality of seismic data. Advantage.

Finally, it should be noted that: the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it can still The technical solutions described in the foregoing embodiments are modified, or some of the technical features are equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Except for the technical features described in the instructions, all are known technologies by those skilled in the art.

Claims (10)

1. The imaging-oriented seismic data construction method is characterized in that the imaging-oriented seismic data construction method comprises: Step 1: Design the target observation system according to the imaging requirements of underground geological targets; Step 2: Transform the seismic data collected in the field from the time domain to the frequency domain; Step 3: Transform the seismic data in the frequency domain to the frequency wavenumber domain; Step 4: Find the Fourier coefficient with the largest frequency amplitude value for each frequency; Step 5: Obtain the optimal reconstruction coefficient; Step 6: Inverse Fourier transform is performed using the optimal reconstruction coefficient to obtain the optimally constructed seismic data in line with the target observation system. 2. The imaging-oriented seismic data construction method according to claim 1, characterized in that, in step 1, the seismic data collected in the field is denoted as D, and the corresponding observation system is denoted as S; according to the underground geological target imaging requirements , considering the illumination of underground geological body, design the target observation system M. 3. the imaging-oriented seismic data construction method according to claim 1, is characterized in that, in step 2, input field acquisition seismic data D, do Fourier transform to time domain data (t, x, y) becomes frequency domain data (f, x, y), where t represents time, x and y represent the horizontal and vertical coordinates of space, and f represents frequency. 4. The imaging-oriented seismic data construction method according to claim 1 is characterized in that, in step 3, two-dimensional discrete Fourier transform is done to frequency domain data (f, x, y), converted into frequency wavenumber Domain (f, kx, ky), where kx and ky represent the corresponding wavenumbers in the x-direction and y-direction. 5. the imaging-oriented seismic data construction method according to claim 1, is characterized in that, in step 4, obtains the Fourier coefficient that each frequency amplitude value is maximum, after this coefficient inverse transformation is returned to time domain, Subtract from seismic data until all frequencies are calculated. 6. the imaging-oriented seismic data construction method according to claim 5, is characterized in that, in step 4, for each frequency f, the Fourier coefficient that chooses amplitude value maximum is denoted as (kx, ky) _max , After inverse transforming it back to the time domain, it is subtracted from the acquired seismic data; each frequency f is followed in this way. 7. The imaging-oriented seismic data construction method according to claim 6, characterized in that, in step 4, the frequency f is selected from 0 to 60 Hz. 8. The imaging-oriented seismic data construction method according to claim 6, characterized in that, in step 4, the frequency f is selected from 0 to 65 Hz. 9. The imaging-oriented seismic data construction method according to claim 1, characterized in that in step 5, step 4 is repeated until the error is smaller than a set threshold, and the optimal reconstruction coefficient is obtained. 10. The imaging-oriented seismic data construction method according to claim 1, characterized in that, in step 6, using the optimal reconstruction coefficient, taking the target observation system M as a scale, performing inverse Fourier transform to obtain Seismic data R is constructed by optimizing the imaging at each seismic source and receiving point in the target observation system M.

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