A wide-azimuth wide-frequency seismic data statics correction method and device
By dividing seismic data into azimuth sections and performing frequency-based residual static correction, the differences in static correction accuracy between different azimuth sectors and frequency components in wide-azimuth broadband seismic data were resolved, enabling high-resolution imaging of thin reservoirs and small faults and improving seismic imaging quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2022-08-09
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies fail to fully consider the different requirements of different azimuth sectors and different frequency components of wide-azimuth broadband seismic data for residual static correction accuracy, making it difficult to meet the high-resolution imaging accuracy requirements of thin reservoirs and small fractures.
By dividing the seismic data into azimuths based on the number of times the seismic data is covered, azimuth-specific seismic data and weighting coefficients are obtained. Inversion of near-surface velocity models and reference surface static correction are performed for each azimuth. Combined with pre-stack noise attenuation and wavelet processing, residual static correction is performed for ordinary and dominant azimuths. Spectral analysis is then performed to obtain frequency-divided residual static correction data for the dominant azimuths. Finally, wide-azimuth broadband seismic data static correction is performed.
It improves the accuracy of near-surface velocity models, enhances the signal-to-noise ratio of seismic data, and improves the high-resolution imaging accuracy of thin reservoirs and small fractures, thus meeting the high-precision imaging requirements of thin reservoirs and small fractures.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of geophysical exploration technology, and in particular to a method and apparatus for static correction of wide-azimuth broadband seismic data. Background Technology
[0002] As oil and gas exploration targets gradually shift towards deep-to-ultra-deep, deep-water, and unconventional oil and gas reservoirs, higher requirements are placed on the resolution and imaging accuracy of seismic data.
[0003] In recent years, broadband, wide-azimuth, small-area seismic acquisition techniques have achieved significant practical results. Wide-azimuth seismic data, due to increased illumination and reduced blind spots, provides a more complete seismic wavefield and offers significant advantages in static correction calculations, high-precision velocity analysis, multiple attenuation, and anisotropy analysis. This facilitates the detailed identification of complex structures, thin reservoirs, faults, fractures, and lithological variations. Broadband seismic data, with its wider octave bands, significantly improves data fidelity, resolution, and signal-to-noise ratio, resulting in clearer characterization of thin sand bodies and faults with stronger resolution. Simultaneously, low-frequency signals exhibit resistance to attenuation and strong penetration; lower frequency components allow for deeper energy propagation, improving high-resolution imaging of deep, thin reservoirs, high-precision imaging of small faults, and interpretation accuracy. The increase in high-frequency bands improves inversion resolution, while the increase in low-frequency bands reduces inversion ambiguity, significantly lowering exploration risks. In conclusion, broadband, wide-azimuth, high-density, small-area seismic data places higher demands on seismic data processing.
[0004] Static correction is a crucial step in seismic data processing and forms the foundation for processing high-resolution seismic data with thin interbedded layers. Static correction can be divided into long-wavelength component static correction and short-wavelength component static correction. Long-wavelength component static correction is also known as low-frequency component static correction, while short-wavelength component static correction is known as high-frequency component static correction. The terms "long-wavelength" and "short-wavelength" refer to the length of the field observation array. Static correction caused by changes in low-velocity layers exceeding one array length is called the long-wavelength component. Generally, it has little impact on the seismic profile and mainly affects the morphology of geological structures. Static correction caused by changes in low-velocity layers within a shorter array length is called the short-wavelength component. It affects the signal-to-noise ratio of the seismic profile, as well as the identification and description of micro-amplitude structures and thin interbedded lithologies.
[0005] Current near-surface modeling methods all assume that near-surface velocity does not change with azimuth, i.e., near-surface velocity is isotropic. However, in complex surface areas, due to the acquisition of wide-azimuth seismic data, the azimuth anisotropy of near-surface velocity is more severe. Therefore, in the static calibration process of the reference surface, the characteristics of wide-azimuth seismic data should be fully considered and utilized to improve the accuracy of near-surface velocity model inversion and static calibration calculation.
[0006] In high-resolution seismic data processing, residual static correction is crucial and has become a major factor affecting the quality of seismic profile imaging. Since different azimuth sectors and frequency components have varying effects on residual static correction—for example, high-frequency signals in seismic data are more sensitive to it—poor residual static correction can destroy the details of subsurface structures and the characteristics of stratigraphic reflection wave groups in the seismic profile. This can cause incoherent superposition of reflection signals between seismic traces, reduce the accuracy of velocity analysis, and ultimately destroy the wavelet characteristics of the superimposed profile, thus lowering its resolution.
[0007] Existing technologies for static correction of wide-azimuth broadband seismic data do not consider the different requirements of different azimuth sectors and different frequency components for the accuracy of residual static correction, making it difficult to meet the high-resolution imaging accuracy requirements of thin reservoirs and small fractures. Summary of the Invention
[0008] The limitations of conventional static correction and residual static correction methods for reference planes in seismic data, which do not fully consider the drawbacks of wide azimuth and broadband data, make it difficult to meet the high-resolution imaging requirements of thin reservoirs and small fractures. The purpose of this invention is to provide a static correction method and apparatus for wide azimuth and broadband seismic data to improve the imaging accuracy and resolution of thin reservoirs and small fractures.
[0009] To achieve the above objectives, the present invention provides a method for static correction of wide-azimuth broadband seismic data, the method comprising:
[0010] Based on the seismic data, the azimuth is divided into sub-azimuths, and the sub-azimuth seismic data and the sub-azimuth seismic data weighting coefficients are obtained.
[0011] Surface velocity model inversion is performed based on azimuth seismic data. By combining the weighting coefficients of azimuth seismic data, near-surface velocity model of wide-azimuth seismic data is obtained, and wide-azimuth reference surface static correction is performed.
[0012] Based on the static correction of the broad azimuth reference plane, perform residual static correction for each azimuth. Divide the azimuth into ordinary azimuth and dominant azimuth, and obtain the residual static correction seismic data of ordinary azimuth and dominant azimuth.
[0013] Spectral analysis is performed on the seismic data with dominant azimuth residual static correction, frequency bands are divided for dominant azimuth frequency-based residual static correction, and dominant azimuth frequency-based residual static correction seismic data is obtained.
[0014] Wide-azimuth broadband seismic data static correction is performed based on the dominant azimuth frequency residual static correction seismic data, the ordinary azimuth residual static correction seismic data, and the weighting coefficients of the azimuth seismic data.
[0015] Furthermore, based on the seismic data, azimuth angles are divided into component azimuths, and azimuth-specific seismic data and weighting coefficients for each azimuth are obtained.
[0016] Based on the total number of seismic data coverage times for the target reservoir, azimuth angles are divided to obtain sub-azimuths, and the number of seismic data coverage times for each sub-azimuth is obtained.
[0017] The weighting coefficients for seismic data by azimuth are obtained based on the number of times the seismic data is covered by each azimuth and the total number of times the seismic data is covered.
[0018] Furthermore, the weighting coefficients for the azimuth-specific seismic data are obtained based on the number of times the seismic data is covered by each azimuth and the total number of times the seismic data is covered.
[0019]
[0020] Where i represents the orientation, W azimuth(i) For the weighting coefficients of the i-axis seismic data, fold azimuth(i) For i-axis azimuth seismic data coverage times, fold wide-azimuth This represents the total number of earthquake data coverage events.
[0021] Furthermore, surface velocity model inversion is performed based on azimuth-based seismic data. Combined with weighting coefficients from the azimuth-based seismic data, a near-surface velocity model for wide-azimuth seismic data is obtained, and wide-azimuth reference surface static correction is performed, including...
[0022] Prestack shot gather data are extracted from azimuth seismic data, and first arrival picking of azimuth seismic data is performed.
[0023] Tomographic inversion was performed on the first arrivals of the seismic data by azimuth to obtain the near-surface velocity models by azimuth.
[0024] Near-surface velocity models for wide-azimuth seismic data are obtained based on near-surface velocity models for each azimuth and weighting coefficients for each azimuth seismic data.
[0025] Furthermore, based on the near-surface velocity model for each azimuth and the weighting coefficients of the azimuth seismic data, the near-surface velocity model for wide-azimuth seismic data is obtained as follows:
[0026]
[0027] Where i represents the direction, n represents the number of directions, and W azimuth(i) The weighting coefficients for the i-axis seismic data, Velocity azimuth(i) Velocity is a near-surface velocity model for the i-th azimuth. wide-azimuth A near-surface velocity model for wide-azimuth seismic data;
[0028] Based on the near-surface velocity model of wide-azimuth seismic data, static correction of the wide-azimuth reference plane is performed.
[0029] Furthermore, residual static correction is performed on each azimuth based on the wide azimuth reference surface static correction. Within each azimuth, ordinary azimuths and dominant azimuths are divided, and residual static corrected seismic data for both are obtained.
[0030] Pre-stack noise attenuation and wavelet processing are performed based on static correction of the wide azimuth reference plane.
[0031] Perform high-precision velocity analysis by azimuth of the azimuth gather data;
[0032] Perform residual static correction based on high-precision velocity analysis of each azimuth;
[0033] Based on the subsurface target reservoir structure and fault strike, the subsurface target is divided into ordinary subsurface target and dominant subsurface target. Among them, the subsurface target reservoir structure and fault strike are abundant and the subsurface target reservoir structure and fault strike are infertile and ordinary subsurface target.
[0034] Obtain seismic data with residual static correction for ordinary and dominant azimuth sub- ...
[0035] Furthermore, spectral analysis is performed on the seismic data with dominant azimuth residual static correction, frequency bands are divided for dominant azimuth frequency-based residual static correction, and the resulting dominant azimuth frequency-based residual static correction seismic data includes...
[0036] Spectral analysis was performed on the direct and reflected waves of the seismic data with dominant azimuth residual static correction.
[0037] Based on spectral analysis, the seismic data with dominant azimuth residual static correction are divided into low-frequency, mid-frequency, and high-frequency bands.
[0038] Frequency-divided residual static correction is performed on the low-frequency, mid-frequency, and high-frequency bands of the seismic data with dominant azimuth residual static correction to obtain dominant azimuth frequency-divided residual static correction seismic data.
[0039] Furthermore, the low-frequency band, mid-frequency band, and high-frequency band overlap, with overlap between the low-frequency band and the mid-frequency band, and overlap between the mid-frequency band and the high-frequency band.
[0040] The present invention also provides a wide-azimuth broadband seismic data static correction device, the device comprising:
[0041] The azimuth division unit is used to divide seismic data into azimuth components, obtain azimuth-based seismic data and weighting coefficients for each azimuth component.
[0042] The wide-azimuth reference surface static correction unit is used to perform surface velocity model inversion based on azimuth seismic data, and to obtain the near-surface velocity model of wide-azimuth seismic data by combining the weighting coefficients of the azimuth seismic data, and to perform wide-azimuth reference surface static correction.
[0043] The azimuth residual static correction unit is used to perform azimuth residual static correction based on the wide azimuth reference surface static correction. It divides the azimuth into ordinary azimuth and dominant azimuth and obtains the residual static correction seismic data of ordinary azimuth and dominant azimuth.
[0044] The azimuth-frequency residual static correction unit is used to perform spectral analysis on the seismic data with dominant azimuth residual static correction, divide the frequency bands for dominant azimuth-frequency residual static correction, and obtain dominant azimuth-frequency residual static correction seismic data.
[0045] The wide-azimuth broadband static correction unit is used to perform wide-azimuth broadband seismic data static correction based on the dominant azimuth frequency-divided residual static correction seismic data, the ordinary azimuth residual static correction seismic data, and the weighting coefficients of the azimuth seismic data.
[0046] Furthermore, the azimuth division unit is used to divide the seismic data into azimuth components, obtain the azimuth-specific seismic data and the weighting coefficients for the azimuth-specific seismic data, including...
[0047] Based on the total number of seismic data coverage times for the target reservoir, azimuth angles are divided to obtain sub-azimuths, and the number of seismic data coverage times for each sub-azimuth is obtained.
[0048] The weighting coefficients for seismic data by azimuth are obtained based on the number of times the seismic data is covered by each azimuth and the total number of times the seismic data is covered.
[0049] Furthermore, the wide-azimuth reference surface static correction unit is used to perform surface velocity model inversion based on azimuth-based seismic data, combine the weighting coefficients of the azimuth-based seismic data to obtain the near-surface velocity model of the wide-azimuth seismic data, and perform wide-azimuth reference surface static correction, including...
[0050] Prestack shot gather data are extracted from azimuth seismic data, and first arrival picking of azimuth seismic data is performed.
[0051] Tomographic inversion was performed on the first arrivals of the seismic data by azimuth to obtain the near-surface velocity models by azimuth.
[0052] Near-surface velocity models for wide-azimuth seismic data are obtained based on near-surface velocity models for each azimuth and weighting coefficients for each azimuth seismic data.
[0053] Furthermore, the azimuth residual static correction unit is used to perform azimuth residual static correction based on the wide azimuth reference plane static correction, dividing the azimuth into ordinary azimuth and dominant azimuth, and acquiring residual static corrected seismic data for the ordinary azimuth and dominant azimuth, including...
[0054] Pre-stack noise attenuation and wavelet processing are performed based on static correction of the wide azimuth reference plane.
[0055] Perform high-precision velocity analysis by azimuth of the azimuth gather data;
[0056] Perform residual static correction based on high-precision velocity analysis of each azimuth;
[0057] Based on the subsurface target reservoir structure and fault strike, the subsurface target is divided into ordinary subsurface target and dominant subsurface target. Among them, the subsurface target reservoir structure and fault strike are abundant and the subsurface target reservoir structure and fault strike are infertile and ordinary subsurface target.
[0058] Obtain seismic data with residual static correction for ordinary and dominant azimuth sub- ...
[0059] Furthermore, the azimuth-frequency residual static correction unit is used to perform spectral analysis based on the seismic data with dominant azimuth residual static correction, divide frequency bands for dominant azimuth-frequency residual static correction, and obtain the dominant azimuth-frequency residual static correction seismic data, including...
[0060] Spectral analysis was performed on the direct and reflected waves of the seismic data with dominant azimuth residual static correction.
[0061] Based on spectral analysis, the seismic data with dominant azimuth residual static correction is divided into low-frequency, mid-frequency, and high-frequency bands. The low-frequency and mid-frequency bands overlap, and the mid-frequency and high-frequency bands overlap.
[0062] Frequency-division residual static correction is performed on the low-frequency, mid-frequency, and high-frequency bands of seismic data based on the dominant azimuth residual static correction.
[0063] This invention provides a wide-azimuth broadband seismic data static correction system, including a memory and a processor.
[0064] Memory, used to store programs.
[0065] The processor runs a stored program in memory to perform the above-described wide-azimuth broadband seismic data static correction method.
[0066] Compared with the prior art, the present invention has the following beneficial effects:
[0067] This invention proposes a wide-azimuth broadband seismic data static correction method. Based on the azimuth division of seismic data coverage times, it performs azimuth-specific first arrival picking and azimuth-specific near-surface velocity model inversion, solving the problem of near-surface azimuth anisotropy in velocity models, improving the accuracy of near-surface velocity models, and obtaining more accurate basic static corrections. Building upon the above reference surface static correction, pre-stack noise attenuation and wavelet processing significantly improve the signal-to-noise ratio of seismic data. Then, gathers are extracted based on the divided azimuth angles, and high-precision velocity analysis is performed on gathers from different azimuth angles. In the residual static correction stage, the different requirements of different azimuth sectors and different frequency components for residual static correction accuracy are fully considered, improving the high-resolution imaging accuracy of thin reservoirs and small fractures. This has important guiding significance for the fine interpretation of thin reservoirs and high-precision reservoir prediction. Attached Figure Description
[0068] Figure 1 A flowchart of a wide-azimuth broadband seismic data static correction method according to an embodiment of the present invention is shown;
[0069] Figure 2 This illustration shows a schematic diagram of azimuth division based on seismic data of the target reservoir in an embodiment of the present invention;
[0070] Figure 3a This diagram illustrates a comprehensive pre-stack time migration profile in an embodiment of the present invention. Figure 3b , Figure 3c and Figure 3d The following are schematic diagrams of pre-stack time migration profiles in embodiments of the present invention, with azimuths of 0°–33°, 90°–111°, and 145°–180° respectively.
[0071] Figure 4a A schematic diagram of seismic data in an embodiment of the present invention is shown. Figure 4b This diagram illustrates seismic data after conventional residual static correction in an embodiment of the present invention. Figure 4c This diagram illustrates seismic data with residual static correction at the dominant azimuth of 0° to 33° in an embodiment of the present invention.
[0072] Figure 5a This diagram shows a horizontally stacked cross-section before residual static correction for the dominant azimuth frequency division from 0° to 33° in an embodiment of the present invention. Figure 5b , Figure 5c and Figure 5d The following are schematic diagrams of horizontal superimposed static corrections for the dominant azimuth 0° to 33° in the low-frequency band of 4 to 35 Hz, the mid-frequency band of 30 to 65 Hz, and the high-frequency band of 55 to 110 Hz, respectively.
[0073] Figure 6aThis diagram illustrates a horizontally stacked profile of the initial seismic data in an embodiment of the present invention. Figure 6b This shows a schematic diagram of a horizontally stacked profile of seismic data after wide azimuth broadband static correction in an embodiment of the present invention;
[0074] Figure 7 A schematic diagram of a wide-azimuth broadband seismic data static correction device is shown in an embodiment of the present invention. Detailed Implementation
[0075] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0076] One embodiment of the present invention provides a method for static correction of wide-azimuth broadband seismic data, the flowchart of which is shown below. Figure 1 As shown, the method includes:
[0077] S101 divides the seismic data into azimuth components, obtains the azimuth-based seismic data and the weighting coefficients of the azimuth-based seismic data.
[0078] Based on the total number of seismic data coverages of the target reservoir, azimuth subdivisions are performed to obtain sub-azimuths, and the number of seismic data coverages for each sub-azimuth is obtained. The weighting coefficients for the sub-azimuth seismic data are obtained based on the number of seismic data coverages for each sub-azimuth and the total number of seismic data coverages.
[0079] Specifically, Figure 2 A schematic diagram illustrating azimuth division based on seismic data of the target reservoir is shown. Figure 2 The scales on the left and bottom indicate the target reservoir area with the seismic data statistics points as the origin, in meters; Figure 2 The labels on the right indicate the amplitude of the seismic data. It should be noted that... Figure 2 In the diagram, 0, 5, 10, ..., 350, 355 represent angles, omitting the angle unit (°). The 0 in the diagram can also represent 360 degrees. Figure 2As can be seen, due to the symmetry of seismic data, the sub-azimuths divided from 0° to 180° can also correspond to a certain sub-azimuth data from 180° to 360°. For example, assuming the sub-azimuth is 0° to 33°, it can also represent the sub-azimuths from 180° to 213°. Therefore, seismic data from 180° to 360° can be categorized into the 0° to 180° range. In the target reservoir studied in this embodiment, to ensure that the number of seismic data coverages for each azimuth meets the accuracy requirements for first-arrival picking and velocity analysis, the seismic data from 0° to 180° is divided into 6 azimuths: 0°–33°, 33°–65°, 65°–90°, 90°–111°, 111°–145°, and 145°–180°. The corresponding seismic data from 180° to 360° is also divided into 6 azimuths: 180°–213°, 213°–245°, 245°–270°, 270°–291°, 291°–325°, and 325°–360°. It should be noted that if the reservoir's seismic data can meet the first-arrival picking and velocity analysis accuracy requirements for *a* azimuths, the azimuths can be divided into *a* azimuths, where *a* ranges from 1, 2, 3, ..., n.
[0080] The weighting coefficients for seismic data by azimuth are obtained based on the number of times the seismic data covers each azimuth and the total number of times the seismic data covers each azimuth.
[0081]
[0082] Where i represents the orientation, W azimuth(i) For the weighting coefficients of the i-axis seismic data, fold azimuth(i) For i-axis azimuth seismic data coverage times, fold wide-azimuth This represents the total number of earthquake data coverage events.
[0083] The number of seismic data coverages for azimuths 0°–33°, 33°–65°, 65°–90°, 90°–111°, 111°–145°, and 145°–180° are compared with the total number of seismic data coverages. The weighting coefficients for the seismic data for azimuths 0°–33°, 33°–65°, 65°–90°, 90°–111°, 111°–145°, and 145°–180° are then calculated using the formula above.
[0084] S102 performs surface velocity model inversion based on azimuth-based seismic data, and combines the weighting coefficients of the azimuth-based seismic data to obtain the near-surface velocity model of the wide-azimuth seismic data, and performs wide-azimuth reference surface static correction.
[0085] Prestack shot gather data are extracted from azimuth seismic data, and first arrival picking of azimuth seismic data is performed.
[0086] Tomographic inversion was performed on the first arrivals of the seismic data by azimuth to obtain the near-surface velocity models by azimuth.
[0087] Near-surface velocity models for wide-azimuth seismic data are obtained based on near-surface velocity models for each azimuth and weighting coefficients for each azimuth seismic data.
[0088] Specifically, according to the sub-azimuths divided in step S101, the pre-stack shot gather data of each sub-azimuth are extracted, and the first arrivals of the seismic data of different sub-azimuths are picked.
[0089] Figure 3a This diagram illustrates a full-range pre-stack time migration profile. For example, Figure 3b , Figure 3c and Figure 3d Schematic diagrams of pre-stack time migration profiles at azimuths of 0°–33°, 90°–111°, and 145°–180° are shown respectively. It can be seen that the accuracy of small fault characterization and thin reservoir imaging by azimuth pre-stack time migration is significantly higher than that by omnidirectional pre-stack time migration. These results indicate that the accuracy can be significantly improved by carrying out azimuth first arrival picking and azimuth near-surface velocity model inversion.
[0090] Based on the first arrivals of seismic data in the azimuth ranges of 0°–33°, 33°–65°, 65°–90°, 90°–111°, 111°–145°, and 145°–180°, tomographic inversion was performed to obtain near-surface velocity models for the azimuth ranges of 0°–33°, 33°–65°, 65°–90°, 90°–111°, 111°–145°, and 145°–180°.
[0091] Based on the near-surface velocity models for azimuths 0°–33°, 33°–65°, 65°–90°, 90°–111°, 111°–145°, and 145°–180°, and the weighting coefficients of the azimuth-specific seismic data obtained in step S101, the near-surface velocity model for the wide-azimuth seismic data is obtained, specifically as follows:
[0092]
[0093] Where i represents the sub-direction, and n represents the number of sub-directions. In this embodiment, 6 sub-directions are defined, so n = 6. azimuth(i) The weighting coefficients for the i-axis seismic data, Velocity azimuth(i) Velocity is a near-surface velocity model for the i-th azimuth. wide-azimuth This is a near-surface velocity model for wide-azimuth seismic data.
[0094] Based on the near-surface velocity model of wide-azimuth seismic data, static correction of the wide-azimuth reference plane is performed.
[0095] S103 performs residual static correction by azimuth based on the wide azimuth reference surface static correction, and divides the azimuth into ordinary azimuth and dominant azimuth, and obtains residual static correction seismic data for ordinary azimuth and dominant azimuth.
[0096] Based on step S102 wide azimuth reference plane static correction, pre-stack noise attenuation and wavelet processing are performed to improve the signal-to-noise ratio of wide azimuth reference plane static correction seismic data.
[0097] Perform high-precision velocity analysis by azimuth from gather data of different azimuth directions;
[0098] Perform residual static correction based on high-precision velocity analysis of each azimuth;
[0099] Based on the subsurface target reservoir structure and fault strike of each azimuth, the azimuths are divided into ordinary azimuths and dominant azimuths. Among them, the azimuths with abundant subsurface target reservoir structure and fault strike are dominant azimuths, while the azimuths with poor subsurface target reservoir structure and fault strike are ordinary azimuths. It should be noted that the abundance and poverty of subsurface target reservoir structure and fault strike in each azimuth are relative. Generally speaking, 3 to 5 dominant azimuths are selected from the divided azimuths, that is, 3 to 5 azimuths with relatively abundant subsurface target reservoir structure and fault strike are selected as dominant azimuths.
[0100] Obtain seismic data with residual static correction for ordinary and dominant azimuth sub- ...
[0101] Specifically, in the target reservoir of this embodiment, based on the fault strike of each azimuth, azimuths 0°–33°, 90°–111°, and 145°–180° are classified as dominant azimuths, and seismic data with residual static correction for the dominant azimuths are obtained; azimuths 33°–65°, 65°–90°, and 111°–145° are classified as ordinary azimuths, and seismic data with residual static correction for the ordinary azimuths are obtained. Figure 4a A schematic diagram of the seismic data is shown; Figure 4b A schematic diagram of seismic data after conventional residual static correction is shown; exemplarily, Figure 4c This diagram illustrates seismic data with residual static correction applied to the dominant azimuth from 0° to 33°. From... Figure 4a As can be seen from the elliptical region indicated by the arrow in ~c, the azimuth residual static correction step of the present invention can improve the accuracy of residual static correction amount calculation and improve the imaging accuracy of thin reservoirs and small fractures.
[0102] S104 performs spectral analysis on the seismic data with dominant azimuth residual static correction, divides the frequency bands for dominant azimuth frequency-based residual static correction, and obtains dominant azimuth frequency-based residual static correction seismic data.
[0103] Spectral analysis was performed on the direct and reflected waves of the seismic data with dominant azimuth residual static correction.
[0104] Based on spectral analysis, the seismic data with dominant azimuth residual static correction are divided into low-frequency, mid-frequency, and high-frequency bands. Among these, there is overlap between the low-frequency and mid-frequency bands, and between the mid-frequency and high-frequency bands.
[0105] Frequency-divided residual static correction is performed on the low-frequency, mid-frequency, and high-frequency bands of the seismic data with dominant azimuth residual static correction to obtain dominant azimuth frequency-divided residual static correction seismic data.
[0106] Specifically, the low-frequency band has a frequency range of 4–35 Hz, the mid-frequency band has a frequency range of 30–65 Hz, and the high-frequency band has a frequency range of 55–110 Hz. Frequency-division residual static correction ensures the accuracy of residual static correction in each frequency band, enabling all frequency components to be superimposed in phase, thereby improving the resolution and signal-to-noise ratio of seismic data with azimuth residual static correction.
[0107] Residual static correction is performed on the frequency bands of 4–35 Hz (low frequency band), 30–65 Hz (mid frequency band), and 55–110 Hz (high frequency band) at the dominant azimuth angles of 0°–33°, 90°–111°, and 145°–180°. Exemplary horizontal superimposed profile diagrams of the dominant azimuth angles of 0°–33° at the dominant azimuth angles of 4–35 Hz (low frequency band), 30–65 Hz (mid frequency band), and 55–110 Hz (high frequency band) are shown below. Figure 5b , Figure 5c and Figure 5d As shown. Figure 5a A schematic diagram of the horizontally stacked profile before residual static correction is also shown, representing the dominant azimuth from 0° to 33°. These results demonstrate that the method of this invention fully considers the waveform differences of different spectra and the varying requirements of different spectral components on the accuracy of residual static correction, thus meeting the high-resolution imaging accuracy requirements of thin reservoirs.
[0108] S105 performs wide-azimuth broadband seismic data static correction based on the dominant azimuth frequency residual static correction seismic data, the ordinary azimuth residual static correction seismic data, and the weighting coefficients of the azimuth seismic data.
[0109] Specifically, based on the dominant azimuth residual static correction seismic data obtained in step S104 (0°–33°, 90°–111°, and 145°–180°), the ordinary azimuth residual static correction seismic data obtained in step S103 (33°–65°, 65°–90°, and 111°–145°), and the weighting coefficients of the azimuth seismic data obtained in step S101 (0°–33°, 33°–65°, 65°–90°, 90°–111°, 111°–145°, and 145°–180°), wide-azimuth broadband seismic data static correction data are calculated.
[0110] Figure 6a A schematic diagram of the horizontal stacked profile of the initial seismic data is shown. Figure 6b This shows a schematic diagram of a horizontally stacked profile of seismic data after wide-azimuth broadband static correction. From Figure 6a and Figure 6b As can be seen from the dashed box, the wide-azimuth broadband seismic data static correction method of the present invention can improve the high-resolution imaging accuracy of thin reservoirs and small fractures.
[0111] In summary, the wide-azimuth broadband seismic data static correction method of this invention comprehensively considers the different requirements for static correction accuracy from different azimuth sectors and different frequency components. Furthermore, based on pre-stack noise attenuation and wavelet processing, it extracts different azimuth gathers according to the divided azimuths and conducts fine velocity analysis on each of these gathers. This method improves the high-resolution imaging accuracy of thin reservoirs and small fractures, and has significant guiding significance for high-resolution interpretation and high-precision reservoir prediction of thin reservoirs.
[0112] Another embodiment of the present invention provides a wide-azimuth broadband seismic data static correction device, the structural schematic diagram of which is shown below. Figure 7 As shown, the device includes:
[0113] The azimuth division unit is used to divide seismic data into azimuth components, obtain azimuth-based seismic data and weighting coefficients for each azimuth component.
[0114] The wide-azimuth reference surface static correction unit is used to perform surface velocity model inversion based on azimuth seismic data, and to obtain the near-surface velocity model of wide-azimuth seismic data by combining the weighting coefficients of the azimuth seismic data, and to perform wide-azimuth reference surface static correction.
[0115] The azimuth residual static correction unit is used to perform azimuth residual static correction based on the wide azimuth reference surface static correction. It divides the azimuth into ordinary azimuth and dominant azimuth and obtains the residual static correction seismic data of ordinary azimuth and dominant azimuth.
[0116] The azimuth-frequency residual static correction unit is used to perform spectral analysis on the seismic data with dominant azimuth residual static correction, divide the frequency bands for dominant azimuth-frequency residual static correction, and obtain dominant azimuth-frequency residual static correction seismic data.
[0117] The wide-azimuth broadband static correction unit is used to perform wide-azimuth broadband seismic data static correction based on the dominant azimuth frequency-divided residual static correction seismic data, the ordinary azimuth residual static correction seismic data, and the weighting coefficients of the azimuth seismic data.
[0118] Regarding the apparatus in the above embodiments, the specific manner in which each unit performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.
[0119] An embodiment of the present invention also provides a wide-azimuth broadband seismic data static correction system, including a memory and a processor.
[0120] Memory, used to store programs.
[0121] The processor runs a stored program in memory to perform the above-described wide-azimuth broadband seismic data static correction method.
[0122] Finally, it should be noted that the above description 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, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for static correction of wide-azimuth broadband seismic data, characterized in that, The method includes: Based on the seismic data, the azimuth is divided into sub-azimuths, and the sub-azimuth seismic data and the sub-azimuth seismic data weighting coefficients are obtained. Surface velocity model inversion is performed based on azimuth seismic data. By combining the weighting coefficients of azimuth seismic data, near-surface velocity model of wide-azimuth seismic data is obtained, and wide-azimuth reference surface static correction is performed. Based on the static correction of the broad azimuth reference plane, perform residual static correction for each azimuth. Divide the azimuth into ordinary azimuth and dominant azimuth, and obtain the residual static correction seismic data of ordinary azimuth and dominant azimuth. Spectral analysis is performed on the seismic data with dominant azimuth residual static correction, frequency bands are divided for dominant azimuth frequency-based residual static correction, and dominant azimuth frequency-based residual static correction seismic data is obtained. Broad-azimuth broadband seismic data static correction is performed based on the dominant azimuth frequency residual static correction seismic data, ordinary azimuth residual static correction seismic data, and the weighting coefficients of the azimuth seismic data. The process of dividing seismic data into azimuth components, obtaining azimuth-specific seismic data and weighting coefficients for each azimuth includes... Based on the total number of seismic data coverage times for the target reservoir, azimuth angles are divided to obtain sub-azimuths, and the number of seismic data coverage times for each sub-azimuth is obtained. The weighting coefficients for seismic data by azimuth are obtained based on the number of times the seismic data is covered by each azimuth and the total number of times the seismic data is covered. The weighting coefficients for the azimuth-based seismic data are: in, i Indicates direction. W azimuth(i) for i Weighting coefficients for seismic data by azimuth. fold azimuth(i) for i Number of times seismic data coverage by azimuth fold wide-azimuth This represents the total number of earthquake data coverage events. The step of inverting the surface velocity model based on azimuth-based seismic data, combining the weighting coefficients of the azimuth-based seismic data to obtain the near-surface velocity model of the wide-azimuth seismic data, and performing wide-azimuth reference surface static correction includes... Prestack shot gather data are extracted from azimuth seismic data, and first arrival picking of azimuth seismic data is performed. Tomographic inversion was performed on the first arrivals of the seismic data by azimuth to obtain the near-surface velocity models by azimuth. Near-surface velocity models for wide-azimuth seismic data are obtained based on near-surface velocity models for each azimuth and weighting coefficients for the azimuth seismic data. The near-surface velocity model is as follows: in, i Indicates direction. n Indicates the number of directions. W azimuth(i) for i Weighting coefficients for seismic data by azimuth. Velocity azimuth(i) for i Near-surface velocity model in different directions Velocity wide-azimuth A near-surface velocity model for wide-azimuth seismic data; Based on the near-surface velocity model of wide-azimuth seismic data, static correction of the wide-azimuth reference plane is performed.
2. The method according to claim 1, characterized in that, Based on the wide-azimuth reference surface static correction, azimuth residual static correction is performed. Within each azimuth, ordinary azimuth and dominant azimuth are divided. Residual static corrected seismic data for both ordinary and dominant azimuths are obtained. Pre-stack noise attenuation and wavelet processing are performed based on static correction of the wide azimuth reference plane. Perform high-precision velocity analysis by azimuth of the azimuth gather data; Perform residual static correction based on high-precision velocity analysis of each azimuth; Based on the subsurface target reservoir structure and fault strike, the subsurface target is divided into ordinary subsurface target and dominant subsurface target. Among them, the subsurface target reservoir structure and fault strike are abundant and the subsurface target reservoir structure and fault strike are infertile and ordinary subsurface target. Obtain seismic data with residual static correction for ordinary and dominant azimuth sub- ...
3. The method according to claim 2, characterized in that, Spectral analysis is performed on the seismic data with dominant azimuth residual static correction. Frequency bands are divided for dominant azimuth frequency-based residual static correction. The resulting seismic data with dominant azimuth frequency-based residual static correction includes... Spectral analysis was performed on the direct and reflected waves of the seismic data with dominant azimuth residual static correction. Based on spectral analysis, the seismic data with dominant azimuth residual static correction are divided into low-frequency, mid-frequency, and high-frequency bands. Frequency-divided residual static correction is performed on the low-frequency, mid-frequency, and high-frequency bands of the seismic data with dominant azimuth residual static correction to obtain dominant azimuth frequency-divided residual static correction seismic data.
4. The method according to claim 3, characterized in that, The low-frequency band, mid-frequency band, and high-frequency band overlap. There is overlap between the low-frequency band and the mid-frequency band, and between the mid-frequency band and the high-frequency band.
5. A wide-azimuth broadband seismic data static correction device, characterized in that, The device includes: Azimuth division unit is used to divide seismic data into azimuth components, obtain seismic data of each azimuth component and weighting coefficients of the seismic data of each azimuth component; The wide-azimuth reference surface static correction unit is used to perform surface velocity model inversion based on azimuth seismic data, and to obtain the near-surface velocity model of wide-azimuth seismic data by combining the weighting coefficients of the azimuth seismic data, and to perform wide-azimuth reference surface static correction. The azimuth residual static correction unit is used to perform azimuth residual static correction based on the wide azimuth reference surface static correction. It divides the azimuth into ordinary azimuth and dominant azimuth and obtains the residual static correction seismic data of ordinary azimuth and dominant azimuth. The azimuth-frequency residual static correction unit is used to perform spectral analysis on the seismic data with dominant azimuth residual static correction, divide the frequency bands for dominant azimuth-frequency residual static correction, and obtain dominant azimuth-frequency residual static correction seismic data. The wide azimuth broadband static correction unit is used to perform wide azimuth broadband seismic data static correction based on the dominant azimuth frequency residual static correction seismic data, the ordinary azimuth residual static correction seismic data, and the weighting coefficients of the azimuth seismic data. The azimuth division unit is used to divide the seismic data into azimuth components, obtain the azimuth-specific seismic data and the weighting coefficients for the azimuth-specific seismic data, including... Based on the total number of seismic data coverage times for the target reservoir, azimuth angles are divided to obtain sub-azimuths, and the number of seismic data coverage times for each sub-azimuth is obtained. The weighting coefficients for seismic data by azimuth are obtained based on the number of times the seismic data is covered by each azimuth and the total number of times the seismic data is covered. The wide-azimuth reference surface static correction unit is used to perform surface velocity model inversion based on azimuth-based seismic data, and, combined with the weighting coefficients of the azimuth-based seismic data, to obtain the near-surface velocity model of the wide-azimuth seismic data, and to perform wide-azimuth reference surface static correction, including... Prestack shot gather data are extracted from azimuth seismic data, and first arrival picking of azimuth seismic data is performed. Tomographic inversion was performed on the first arrivals of the seismic data by azimuth to obtain the near-surface velocity models by azimuth. Near-surface velocity models for wide-azimuth seismic data are obtained based on near-surface velocity models for each azimuth and weighting coefficients for each azimuth seismic data.
6. The apparatus according to claim 5, characterized in that, The azimuth residual static correction unit is used to perform azimuth residual static correction based on the wide azimuth reference plane static correction. Within the azimuth sub-azimuth, ordinary azimuth and dominant azimuth sub-azimuth are divided, and residual static correction seismic data for the ordinary azimuth and dominant azimuth sub-azimuth are obtained. Pre-stack noise attenuation and wavelet processing are performed based on static correction of the wide azimuth reference plane. Perform high-precision velocity analysis by azimuth of the azimuth gather data; Perform residual static correction based on high-precision velocity analysis of each azimuth; Based on the subsurface target reservoir structure and fault strike, the subsurface target is divided into ordinary subsurface target and dominant subsurface target. Among them, the subsurface target reservoir structure and fault strike are abundant and the subsurface target reservoir structure and fault strike are infertile and ordinary subsurface target. Obtain seismic data with residual static correction for ordinary and dominant azimuth sub- ...
7. The apparatus according to claim 6, characterized in that, The azimuth-frequency residual static correction unit is used to perform spectral analysis based on the seismic data with dominant azimuth residual static correction, divide frequency bands for dominant azimuth-frequency residual static correction, and obtain the seismic data with dominant azimuth-frequency residual static correction. Spectral analysis was performed on the direct and reflected waves of the seismic data with dominant azimuth residual static correction. Based on spectral analysis, the seismic data with dominant azimuth residual static correction is divided into low-frequency, mid-frequency, and high-frequency bands. The low-frequency and mid-frequency bands overlap, and the mid-frequency and high-frequency bands overlap. Frequency-division residual static correction is performed on the low-frequency, mid-frequency, and high-frequency bands of seismic data based on the dominant azimuth residual static correction.
8. A wide-azimuth broadband seismic data static correction system, characterized in that, Including memory and processor, Memory, used to store programs. The processor executes a stored program in memory to perform the method described in any one of claims 1 to 4.