Seismic data construction method for imaging

Abstract

The present invention provides a method for constructing seismic data for imaging. The method comprises the following steps: step 1: designing a target observation system based on the requirements for imaging underground geological targets; step 2: transforming field-collected seismic data from the time domain to the frequency domain; step 3: transforming the frequency-domain seismic data to the frequency wavenumber domain; step 4: obtaining the Fourier coefficient with the maximum frequency amplitude for each frequency; step 5: obtaining the optimal reconstruction coefficient; and step 6: performing an inverse Fourier transform using the optimal reconstruction coefficient to obtain optimized seismic data that conforms to the target observation system. This method can effectively compensate for problems such as missing seismic data and insufficient coverage caused by field acquisition variations, thereby improving the quality of seismic data, obtaining optimized seismic data, and enhancing the quality of seismic imaging.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas exploration seismic data processing, and in particular to an imaging-oriented seismic data construction method. Background Art

[0002] With the continuous advancement of oil and gas exploration and development, reservoir types are gradually shifting towards complex and subtle reservoirs, placing greater demands on seismic technology for higher resolution and fidelity. Consequently, single-point high-density seismic technology has emerged, requiring single-point reception, wide azimuth angles, and high shot density. This technology has been widely deployed in exploration areas in eastern China, improving imaging resolution and fidelity. However, favorable exploration areas are hampered by surface obstacles. Construction is prohibited in prohibited areas, and both excitation and reception are restricted in restricted areas. This results in significant gaps in seismic data, insufficient illumination of geological targets, and poor imaging quality. Currently, conventional solutions use algorithms based on mathematical transformations to regularize or interpolate seismic data before stacking. This approach fails to account for subsurface illumination of geological targets and is ineffective in improving the imaging of missing seismic data. Another approach involves splicing older data for stacking. However, due to variations in frequency, amplitude, phase, and time difference, the consistency of older data is poor, resulting in suboptimal splicing and unsatisfactory results, making it difficult to meet the requirements of detailed exploration.

[0003] In the Chinese patent application with application number: CN201510346548.6, a method for constructing a velocity model of seismic data is involved, including: (A) obtaining an initial velocity model of the seismic data; (B) using the initial velocity model to offset the survey line to obtain an original offset profile; (C) obtaining each reference velocity model of the initial velocity model under at least one percentage velocity factor; (D) using each reference velocity model to obtain a common reflection point gather; (E) superimposing the common reflection point gather into a multi-channel mini-profile of the velocity analysis point; (F) for each layer, determining a preferred mini-profile, and using the velocity of the velocity analysis point in the reference velocity model under the percentage velocity factor corresponding to the preferred mini-profile as the preferred offset velocity of the velocity analysis point in the corresponding layer; (G) replacing the corresponding velocity of each velocity analysis point in the original velocity model with the preferred offset velocity of each velocity analysis point in each layer.

[0004] In the Chinese patent application with application number: CN202011229691.4, a VIA dual-parameter imaging method for seismic data processing is involved, including: arranging a seismic data acquisition and observation system, including setting the positions of shot points and detection points and the arrangement relationship between the two, using the seismic data acquisition and observation system to collect seismic data, and setting parameters related to seismic wave propagation; calculating the transformation equation of the VIA dual-parameter imaging method; through the above transformation equation, converting t into t0 to realize seismic data imaging.

[0005] Chinese patent application number CN201410049621.9 discloses a method and system for reverse time migration imaging of onshore seismic data. The method comprises: acquiring onshore seismic data; performing strong denoising on the onshore seismic data to obtain strongly denoised data; performing weak denoising on the onshore seismic data to obtain weakly denoised data; constructing a broadband wavelet based on the onshore seismic data; constructing a velocity model based on the strongly denoised data; performing reverse time migration imaging based on the weakly denoised data, broadband wavelet, and velocity model to obtain an initial reverse time migration imaging result; and performing low-frequency noise attenuation on the initial reverse time migration imaging result to obtain a reverse time migration imaging result.

[0006] The above existing technologies are all significantly different from the present invention and fail to solve the technical problem we want to solve. Therefore, we have invented a new imaging-oriented seismic data construction method. Summary of the Invention

[0007] The purpose of the present invention is to provide an imaging-oriented seismic data construction method with the goal of improving imaging quality and compensating for the reduction in seismic data quality caused by acquisition distortion in surface obstacle areas.

[0008] The object of the present invention can be achieved by the following technical measures: a method for constructing seismic data for imaging, the method comprising:

[0009] Step 1: Design the target observation system according to the underground geological target imaging requirements;

[0010] Step 2: transform the field collected seismic data from the time domain to the frequency domain;

[0011] Step 3: transform the frequency domain seismic data into the frequency wavenumber domain;

[0012] Step 4: For each frequency, find the Fourier coefficient with the maximum frequency amplitude value;

[0013] Step 5: Obtain the optimal reconstruction coefficient;

[0014] Step 6: Use the optimal reconstruction coefficients to perform inverse Fourier transform to obtain optimized constructed seismic data that meets the target observation system.

[0015] The purpose of the present invention can also be achieved by the following technical measures:

[0016] 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 the underground geological target and considering the illumination of the underground geological body, the target observation system M is designed.

[0017] In step 2, the field collected seismic data D is input, and a Fourier transform is performed on each seismic trace to convert 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 space, and f represents frequency.

[0018] In step 3, a two-dimensional discrete Fourier transform is performed on the frequency domain data (f, x, y) to convert it into the frequency wavenumber domain (f, kx, ky), where kx and ky represent the wavenumbers corresponding to the x direction and y direction.

[0019] In step 4, the Fourier coefficient with the maximum amplitude value of each frequency is obtained, and this coefficient is inversely transformed back to the time domain and subtracted from the seismic data until the calculation of all frequencies is completed.

[0020] In step 4, for each frequency f, select the Fourier coefficient with the largest amplitude value and record it 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 operated according to this method.

[0021] In step 4, the frequency f is selected from 0 to 60 Hz.

[0022] In step 4, the frequency f is selected from 0 to 65 Hz.

[0023] In step 5, step 4 is repeated until the error is less than the set threshold, and the optimal reconstruction coefficient is obtained.

[0024] In step 6, the optimal reconstruction coefficient is used to perform inverse Fourier transform with the target observation system M as the measurement plate to obtain the imaging optimized constructed seismic data R at each source and receiving point position in the target observation system M.

[0025] The imaging-oriented seismic data construction method of the present invention designs a target observation system based on the imaging illumination of the underground geological body, guides the construction of the seismic data wave field, compensates for the illumination of the surface obstruction area, and improves the imaging quality. Compared with the existing technology, the imaging-oriented seismic data construction method of the present invention has the following advantages:

[0026] First, the seismic data obtained by this invention has strong consistency in frequency, phase, and amplitude, which can better compensate for the problems of missing seismic data and insufficient coverage caused by field acquisition variations, thereby improving the quality of seismic data.

[0027] Second, the invention fully considers the imaging illumination 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flowchart of a specific embodiment of the imaging-oriented seismic data construction method of the present invention;

[0029] Figure 2 A schematic diagram of the actual location of a shot point collected in the field in a specific embodiment of the present invention;

[0030] Figure 3 A schematic diagram of a shot point target observation system configured according to imaging requirements in a specific embodiment of the present invention;

[0031] Figure 4 A schematic diagram of a seismic single shot record obtained by imaging optimization construction in a specific embodiment of the present invention;

[0032] Figure 5 A schematic diagram of a superimposed cross section of imaging optimization construction data in a specific embodiment of the present invention;

[0033] Figure 6 A schematic diagram of superimposed cross sections of data reconstructed using a conventional method in one embodiment of the present invention;

[0034] Figure 7 A schematic diagram of the actual location of a shot point collected in the field in a specific embodiment of the present invention;

[0035] Figure 8 A schematic diagram of a shot point target observation system configured according to imaging requirements in a specific embodiment of the present invention;

[0036] Figure 9 A schematic diagram of a seismic single shot record obtained by imaging optimization construction in a specific embodiment of the present invention;

[0037] Figure 10 A schematic diagram of a migration profile of imaging optimization construction data in a specific embodiment of the present invention;

[0038] Figure 11 Schematic diagram of a migration profile of data reconstructed using a conventional method in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0039] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0041] The imaging-oriented seismic data construction method of the present invention includes the following steps:

[0042] (1) Design the target observation system based on the imaging requirements of underground geological targets and considering the illumination of underground geological bodies;

[0043] (2) transforming field-collected seismic data from the time domain to the frequency domain;

[0044] (3) transforming frequency domain seismic data into frequency wavenumber domain;

[0045] (4) Obtain the Fourier coefficient with the largest amplitude value for each frequency, transform this coefficient back to the time domain, and subtract it from the acquired seismic data until the calculation of all frequencies is completed;

[0046] (5) Repeat step 4 until the error is less than the set threshold, and the optimal reconstruction coefficient is obtained;

[0047] (6) Using the optimal reconstruction coefficients to perform inverse Fourier transform, we can obtain the imaging optimization and construction seismic data that conforms to the target observation system.

[0048] In a specific embodiment 1 of the present invention, the imaging-oriented seismic data construction method of the present invention specifically includes the following steps:

[0049] (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 the underground geological target and considering the illumination of the underground geological body, the target observation system M is designed.

[0050] (2) Input the seismic data D collected in the field, and perform Fourier transform on each seismic trace to convert 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 space, and f represents frequency.

[0051] (3) Perform a two-dimensional discrete Fourier transform on the frequency domain data (f, x, y) and convert it into the frequency wavenumber domain (f, kx, ky), where kx and ky represent the wavenumbers corresponding to the x direction and y direction.

[0052] (4) For each frequency f, select the Fourier coefficient with the largest amplitude value and record it 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 operated according to this method.

[0053] (5) Repeat step 4 until the error is less than the set threshold, and obtain the optimal reconstruction coefficient.

[0054] (6) Using the optimal reconstruction coefficient and taking the target observation system M as the measurement plate, the inverse Fourier transform is performed to obtain the imaging optimization constructed seismic data R at each source and receiving point position in the target observation system M.

[0055] In a specific embodiment 2 of the present invention, as Figure 1 As shown, Figure 1 Shown are the operating steps of the imaging-oriented seismic data construction method.

[0056] In step 101, the actual observation system is collected in the field. Due to the influence of surface obstacles, the observation system S shot points are seriously missing ( Figure 2 ), according to the geological body lighting requirements, a target observation system M for the shot point is set up ( Figure 3 ).

[0057] Step 102: Input the seismic data D collected in the field, and perform Fourier transform on each seismic trace to convert 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 space, and f represents frequency.

[0058] Step 103: Perform a two-dimensional discrete Fourier transform on the frequency domain data (f, x, y) to convert it into the frequency wave number domain (f, kx, ky), where kx and ky represent the wave numbers corresponding to the x direction and y direction.

[0059] Step 104: For each frequency f, select the Fourier coefficient with the largest amplitude value and record it as (kx, ky) max , after inversely transforming it back to the time domain, it is subtracted from the acquired seismic data. Each frequency f is operated according to this method. The frequency f here is selected from 0 to 60 Hz.

[0060] Step 105: Repeat step 4 until the error is less than the set threshold, and obtain the optimal reconstruction coefficient.

[0061] Step 106: Using the optimal reconstruction coefficient and the target observation system M as the measurement plate, perform inverse Fourier transform to obtain the imaging optimization reconstruction seismic data R ( Figure 4 ).

[0062] 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 superimposed with the seismic data R obtained by optimizing the target observation system M designed by the present invention. It can be found that the superposition results of the optimized seismic data of the present invention ( Figure 5 ) is better than the superposition result of the conventional method to reconstruct the data ( Figure 6 ), verifying the practical effect of the present invention.

[0063] In a third specific embodiment of the present invention, the imaging-oriented seismic data construction method of the present invention specifically includes the following steps:

[0064] In step 101, the actual observation system is collected in the field. Due to the influence of surface obstacles, the observation system S shot points are seriously missing ( Figure 7 ), according to the geological body lighting requirements, a target observation system M( Figure 8 ).

[0065] Step 102: Input the seismic data D collected in the field, and perform Fourier transform on each seismic trace to convert 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 space, and f represents frequency.

[0066] Step 103: Perform a two-dimensional discrete Fourier transform on the frequency domain data (f, x, y) to convert it into the frequency wave number domain (f, kx, ky), where kx and ky represent the wave numbers corresponding to the x direction and y direction.

[0067] Step 104: For each frequency f, select the Fourier coefficient with the largest amplitude value and record it as (kx, ky) max , after inversely transforming it back to the time domain, it is subtracted from the acquired seismic data. Each frequency f is operated according to this method. The frequency f here is selected from 0 to 65 Hz.

[0068] Step 105: Repeat step 4 until the error is less than the set threshold, and obtain the optimal reconstruction coefficient.

[0069] Step 106: Using the optimal reconstruction coefficient and the target observation system M as the measurement plate, perform inverse Fourier transform to obtain the imaging optimization reconstruction seismic data R ( Figure 9 ).

[0070] 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 the optimized construction of the target observation system M designed by the present invention are respectively subjected to pre-stack time migration. It can be found that the migration results of the seismic data optimized by the present invention ( Figure 10 ) is better than the migration result of the conventional method to reconstruct the data ( Figure 11 ), which verifies the advantages of the present invention in improving the imaging quality of seismic data.

[0071] Finally, it should be noted that the above description is merely 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 aforementioned embodiments, those skilled in the art may modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0072] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. A method for constructing seismic data for imaging, characterized in that: The imaging-oriented seismic data construction method includes: Step 1: Design the target observation system according to the underground geological target imaging requirements; Step 2: transform the field collected seismic data from the time domain to the frequency domain; Step 3: transform the frequency domain seismic data into the frequency wavenumber domain; Step 4: For each frequency, find the Fourier coefficient with the maximum frequency amplitude value; Step 5: Obtain the optimal reconstruction coefficient; Step 6: Use the optimal reconstruction coefficients to perform inverse Fourier transform to obtain optimized seismic data that meets the target observation system; 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 underground geological body illumination, the target observation system M is designed; In step 2, the field collected seismic data D is input, and a Fourier transform is performed on each seismic trace to convert 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 space, and f represents frequency; In step 3, a two-dimensional discrete Fourier transform is performed on the frequency domain data (f, x, y) to convert it into the frequency wavenumber domain (f, kx, ky), where kx and ky represent the wavenumbers corresponding to the x-direction and y-direction; In step 4, the Fourier coefficient with the maximum amplitude value of each frequency is obtained, and this coefficient is inversely transformed back to the time domain and subtracted from the seismic data until all frequencies are calculated; the frequency f is selected from 0 to 65 Hz; In step 5, step 4 is repeated until the error is less than the set threshold, and the optimal reconstruction coefficient is obtained; In step 6, the optimal reconstruction coefficient is used to perform inverse Fourier transform with the target observation system M as the measurement plate to obtain the imaging optimized constructed seismic data R at each source and receiving point position in the target observation system M.

2. The imaging-oriented seismic data construction method according to claim 1, characterized in that: In step 4, for each frequency f, select the Fourier coefficient with the largest amplitude value and record it 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 operated according to this method.

3. The imaging-oriented seismic data construction method according to claim 1, characterized in that: In step 4, the frequency f is selected from 0 to 60 Hz.

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