Imaging method, system, electronic device and storage medium based on reflected wave

Abstract

The present disclosure relates to an imaging method, system, electronic device, and storage medium based on reflection waves. The imaging method includes: obtaining a first reflection wave, a second reflection wave, and a third reflection wave; determining the velocities of seismic shear waves and seismic longitudinal waves; reconstructing a downgoing wavefield and an upgoing wavefield of the reflection wave; imaging the downgoing wavefield and the upgoing wavefield of the reflection wave to generate an initial image; extracting an incident angle imaging gather of a seismic trace from the initial image, determining a critical reflection angle of the seismic trace based on the velocities of the seismic shear wave and the seismic longitudinal wave; comparing the incident angle of the seismic trace in the incident angle imaging gather with the critical reflection angle, determining noise in the incident angle imaging gather, removing the noise from the incident angle imaging gather, and performing stacking processing to obtain a stacked image. The incident angle gather of the shear-wave converted wave is processed by the critical angle to achieve efficient spatially varying constraint processing, exclude noise from the stacked image, and improve the imaging quality of the shear-wave converted wave migration.

Description

Technical Field

[0001] The present disclosure belongs to the field of geological exploration technology, and in particular relates to an imaging method, system, electronic device and storage medium based on reflection waves. Background Art

[0002] With the development of geophysical exploration technology, the use of multiple types of seismic waves to image underground media can effectively overcome the limitations of traditional methods that rely solely on longitudinal wave imaging. The Sanhu area is located in the eastern Qaidam Basin, with a surface elevation of 2680-2720 meters. The terrain is relatively flat, and the main landforms are hard alkaline and soft alkaline land. The underground target layer in this area is mainly Quaternary (Q1+2) loose sandstone with low structural amplitude structures. The target layer is buried at a depth of 800-2000 meters. The gas layer is relatively shallow. Due to the influence of gas absorption attenuation, the longitudinal wave profile generally shows "low speed, low frequency and phase axis pull-down" seismic anomalies, resulting in the low amplitude structure in the "gas cloud area" not being imaged.

[0003] When seismic waves propagate through interfaces with media of different densities and elastic moduli, shear waves can be converted into longitudinal waves, a phenomenon known as shear-wave conversion waves. These seismic waves can also be used for imaging, providing a more comprehensive understanding of the subsurface. However, in the process of converting waves, accurate wavefield separation is difficult because the three-component wave generators used for field data acquisition and the propagation direction of the seismic waves are not strictly aligned. This results in crosstalk noise in the imaging, affecting image quality. Summary of the Invention

[0004] To address these issues, the present disclosure provides a reflection-wave-based imaging method, system, electronic device, and storage medium. By processing the S-wave converted-wave incident angle gathers using the critical angle, efficient spatially varying constraint processing is achieved, noise is excluded from the stacked image, and the imaging quality of S-wave converted-wave migration is improved.

[0005] In order to solve the above technical problems, the first aspect of the present invention provides an imaging method based on reflected waves, the method comprising:

[0006] Acquire a shear wave reflection of a seismic shear wave in the area to be explored as a first reflection wave, a longitudinal wave reflection of the seismic shear wave as a second reflection wave, and a longitudinal wave reflection of the seismic longitudinal wave as a third reflection wave; and determine a velocity of the seismic shear wave based on the first reflection wave, and determine a velocity of the seismic longitudinal wave based on the third reflection wave;

[0007] reconstructing a downgoing wavefield based on the seismic shear wave and its velocity, and reconstructing an upgoing wavefield of the reflected wave based on the second reflected wave and its velocity, and performing imaging processing on the downgoing wavefield and the upgoing wavefield of the reflected wave using a prestack depth migration technique to generate an initial image;

[0008] Extracting an incident angle imaging gather of a seismic trace from the initial imaging, and determining a critical reflection angle of the seismic trace according to the wave velocity of the seismic shear wave and the wave velocity of the seismic longitudinal wave;

[0009] The incident angle of the seismic trace in the incident angle imaging gather is compared with the critical reflection angle, the noise in the incident angle imaging gather is determined according to the comparison result, and the noise is removed from the incident angle imaging gather; and the incident angle imaging gather after the noise removal is stacked to obtain a stacked imaging.

[0010] According to a preferred embodiment of the present invention, obtaining a shear wave reflection wave of a seismic shear wave in a to-be-explored area as a first reflection wave, a longitudinal wave reflection wave of a seismic shear wave as a second reflection wave, and a longitudinal wave reflection wave of a seismic longitudinal wave as a third reflection wave includes:

[0011] Exciting seismic shear waves through a shear wave excitation source to obtain first seismic data;

[0012] Acquiring a shear wave reflection wave of the first seismic data in a horizontal direction as a first reflection wave;

[0013] Acquiring a longitudinal wave reflection wave of the seismic data in a vertical direction as a second reflection wave;

[0014] Exciting seismic longitudinal waves through a longitudinal wave excitation source to obtain second seismic data;

[0015] A longitudinal wave reflection wave of the second seismic data in the vertical direction is obtained as a third reflection wave.

[0016] According to a preferred embodiment of the present invention, extracting the incident angle imaging gathers of the seismic traces from the initial imaging, and determining the critical reflection angle of the seismic traces according to the wave velocities of the seismic shear waves and the seismic longitudinal waves, comprises:

[0017] Acquire the seismic traces of the initial imaging and arrange them in the order of incident angles to form the incident angle imaging trace gather;

[0018] For each imaging point in the initial imaging, a critical reflection angle of a longitudinal wave reflection of the seismic shear wave in the seismic trace at the imaging point is calculated based on the seismic shear wave velocity and the longitudinal wave velocity of the seismic shear wave at the imaging point; wherein when the incident angle of the seismic shear wave is greater than the critical reflection angle, no longitudinal wave reflection wave is generated;

[0019] The critical angle distribution of the initial imaging is generated by integrating the reflection critical angles of various imaging points.

[0020] According to a preferred embodiment of the present invention, the method further comprises:

[0021] Static correction and denoising are performed on the second reflected wave to remove the secondary shear wave, the primary longitudinal wave reflected wave and the longitudinal wave converted wave in the second reflected wave.

[0022] In order to solve the above technical problems, the second aspect of the present invention provides an imaging system based on reflected waves, the imaging system comprising:

[0023] A seismic wave acquisition module, configured to acquire a shear wave reflection of a seismic shear wave in a to-be-explored area as a first reflection wave, a longitudinal wave reflection of a seismic shear wave as a second reflection wave, and a longitudinal wave reflection of a seismic longitudinal wave as a third reflection wave;

[0024] a wave velocity determination module, configured to determine the wave velocity of the seismic shear wave according to the first reflected wave, and determine the wave velocity of the seismic longitudinal wave according to the third reflected wave;

[0025] an imaging processing module, configured to reconstruct a downgoing wavefield based on the seismic shear wave and its velocity, and to reconstruct an upgoing wavefield of the reflected wave based on the second reflected wave and its velocity; and to perform imaging processing on the downgoing wavefield and the upgoing wavefield of the reflected wave using a prestack depth migration technique to generate an initial image;

[0026] A critical angle calculation module is used to extract the incident angle imaging gather of the seismic trace from the initial imaging, and determine the reflection critical angle of the seismic trace according to the wave velocity of the seismic shear wave and the wave velocity of the seismic longitudinal wave;

[0027] The imaging processing module is further used to compare the incident angle of the seismic trace in the incident angle imaging gather with the critical reflection angle, determine the noise in the incident angle imaging gather based on the comparison result, and remove the noise from the incident angle imaging gather; and obtain a stacked image by stacking the incident angle imaging gather after noise removal.

[0028] According to a preferred embodiment of the present invention, the imaging system further comprises: a shear wave excitation source module for exciting seismic shear waves; and a longitudinal wave excitation source module for exciting seismic longitudinal waves;

[0029] The seismic wave acquisition module is specifically used to acquire first seismic data; acquire a shear wave reflection wave of the first seismic data in the horizontal direction as a first reflection wave; and acquire a longitudinal wave reflection wave of the seismic data in the vertical direction as a second reflection wave;

[0030] The seismic wave acquisition module is specifically used to acquire second seismic data; and acquire a longitudinal wave reflection wave of the second seismic data in a vertical direction as a third reflection wave.

[0031] According to a preferred embodiment of the present invention, the critical angle calculation module is specifically used to obtain the seismic traces of the initial imaging and arrange them in the order of incident angle to form the incident angle imaging trace set; for each imaging point in the initial imaging, the reflection critical angle of the longitudinal wave reflection wave of the seismic shear wave in the seismic trace at the imaging point is calculated based on the wave velocity and longitudinal wave velocity of the seismic shear wave at the imaging point; wherein, when the incident angle of the seismic shear wave is greater than the reflection critical angle, the longitudinal wave reflection wave cannot be generated; and the critical angle distribution of the initial imaging is generated by integrating the reflection critical angles of each imaging point.

[0032] According to a preferred embodiment of the present invention, the system further includes: a data preprocessing module for performing static correction and denoising on the second reflected wave, and removing the secondary shear wave, the primary longitudinal wave reflected wave and the longitudinal wave converted wave in the second reflected wave.

[0033] In order to solve the above technical problems, the third aspect of the present invention provides an electronic device, comprising:

[0034] processor; and

[0035] A memory storing computer-executable instructions, wherein when the computer-executable instructions are executed, the processor is caused to perform the method described in any one of the above embodiments.

[0036] In order to solve the above technical problems, the fourth aspect of the present invention proposes a computer storage medium, wherein the computer storage medium stores one or more programs, and when the one or more programs are executed by a processor, the method described in any one of the above embodiments is implemented.

[0037] Compared with the prior art, the present invention has the following advantages: the present invention performs geological exploration by exciting seismic shear waves and seismic longitudinal waves, obtains shear wave reflection waves and longitudinal wave reflection waves of the seismic shear waves and seismic longitudinal waves, and thereby determines the velocity of the seismic shear waves and the velocity of the seismic longitudinal waves, reconstructs the downgoing wavefield by the velocity of the seismic shear waves, reconstructs the upgoing wavefield of the reflected waves by the velocity of the seismic longitudinal waves, and performs imaging based on the downgoing wavefield and the upgoing wavefield of the reflected waves, obtains the critical angle distribution of the imaging space by the velocity of the seismic shear waves and the velocity of the seismic longitudinal waves, determines the noise in the shear wave conversion wave incident angle gather by the critical angle, and re-superimposes the image after removing the noise in the gather. The shear wave conversion wave incident angle gather is processed by the critical angle to achieve efficient spatial variation constraint processing, exclude noise from the superimposed image, and improve the imaging quality of the shear wave conversion wave migration.

[0038] Other features and advantages of the present disclosure will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present disclosure. The purposes and other advantages of the present disclosure can be realized and obtained by the structures indicated in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 A schematic flow chart of an imaging method based on reflected waves according to an embodiment of the present disclosure is shown;

[0041] Figure 2 shows a schematic diagram of SS wave data according to an embodiment of the present disclosure;

[0042] Figure 3 shows a schematic diagram of SP wave data according to an embodiment of the present disclosure;

[0043] Figure 4 shows a schematic diagram of PP wave data according to an embodiment of the present disclosure;

[0044] Figure 5 shows a schematic diagram of longitudinal wave velocity and depth according to an embodiment of the present disclosure;

[0045] Figure 6 shows a schematic diagram of shear wave velocity and depth according to an embodiment of the present disclosure;

[0046] Figure 7 A schematic diagram of a rake gather applying a critical angle resection according to an embodiment of the present disclosure is shown;

[0047] Figure 8 A schematic diagram of a back-angle gather with critical angle removal according to an embodiment of the present disclosure is shown;

[0048] Figure 9 A schematic cross-sectional view of superimposed imaging before resection according to an embodiment of the present disclosure is shown;

[0049] Figure 10 A schematic cross-sectional view of superimposed imaging after application of resection according to an embodiment of the present disclosure is shown;

[0050] Figure 11 A block diagram of an imaging system based on reflected waves according to an embodiment of the present disclosure is shown;

[0051] Figure 12 A schematic structural diagram of an electronic device according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0053] The same reference numerals in the accompanying drawings represent the same or similar elements, components or parts, and thus repeated descriptions of the same or similar elements, components or parts may be omitted below. It should also be understood that although the first, second, third and other numbered adjectives may be used herein to describe various devices, elements, components or parts, these devices, elements, components or parts should not be limited by these adjectives. In other words, these adjectives are only used to distinguish one from another. For example, the first device may also be called the second device, but this does not deviate from the essential technical solution of the present invention. In addition, the terms "and / or" and "and / or" refer to all combinations including any one or more of the listed items.

[0054] See also Figure 1 , Figure 1 FIG. 1 is a flow chart of an imaging method based on reflected waves provided by the present invention, such as Figure 1 As shown, the method includes:

[0055] S11. Obtain the shear wave reflection wave of the seismic shear wave in the area to be explored as the first reflection wave, the longitudinal wave reflection wave of the seismic shear wave as the second reflection wave, and the longitudinal wave reflection wave of the seismic longitudinal wave as the third reflection wave; and determine the wave velocity of the seismic shear wave according to the first reflection wave, and determine the wave velocity of the seismic longitudinal wave according to the third reflection wave.

[0056] In this embodiment, field seismic data acquisition is based on a geological survey and observation system design. Seismic data acquisition is conducted in the field using a P-wave excitation source and a S-wave excitation source to artificially excite S- and P-wave seismic waves. Three-component seismometers are deployed on the surface to receive seismic data. A three-component seismometer is an instrument used to record and analyze ground vibrations. It can simultaneously detect seismic wave components in three different directions (typically the horizontal X- and Y-axes, and the vertical Z-axis).

[0057] In this embodiment, the collected seismic data is analyzed and processed, wherein the SV wave data and SH wave data of the shear wave are received in the X-axis component and the Y-axis component of the seismic shear wave data, and the SV wave data and the SH wave data constitute the SS wave data. The SV wave is a vertical shear shear wave, and the SV wave is a wave in which the particle vibration occurs in a plane perpendicular to the wave propagation plane. The SH wave is a horizontal shear shear wave, and the SH wave is a wave in which the particle vibration occurs in a plane parallel to the wave propagation plane. The SS wave data is a type of seismic wave, and generally refers to a specific form or path of a shear wave (S wave) propagating in an underground medium. The S wave is a shear wave, and its vibration direction is perpendicular to the propagation direction, as shown in FIG. Figure 2 As shown. Theoretically, there is no shear wave data in the Z-axis component, and what is received is the shear wave converted wave data. Figure 3 In the seismic longitudinal wave data, the Z-axis component is the longitudinal wave data, and the PP wave data refers to the seismic wave that is emitted from the earthquake source, propagates to the middle of the longitudinal wave, and then reflects once on the surface and propagates to the measurement point in the form of longitudinal wave. Figure 4 As shown, the X-axis component and the Y-axis component contain longitudinal wave conversion wave data, and the PS wave data refers to a converted wave among the reflected shear wave (S wave) and the transmitted shear wave, the reflected longitudinal wave and the transmitted longitudinal wave generated when the longitudinal wave (P wave) is obliquely incident on the elastic interface.

[0058] Specifically, a shear wave is excited by a shear wave excitation source to obtain the first seismic data; the shear wave reflection waves of the first seismic data in the horizontal and vertical directions are obtained as the first reflection wave; the longitudinal wave reflection waves of the seismic data in the vertical direction are obtained as the second reflection wave; the longitudinal wave is excited by a longitudinal wave excitation source to obtain the second seismic data; the longitudinal wave reflection waves of the second seismic data in the vertical direction are obtained as the third reflection wave.

[0059] In this embodiment, if Figure 5 、 Figure 6 As shown, based on the data processing of PP waves and SS waves, the P-wave and S-wave velocity models are established. By utilizing the arrival time information of the first arrival wave, the propagation velocities of the P-wave and S-wave can be preliminarily estimated. By comparing the arrival times of the first arrival waves at different shot offsets, the variation of velocity with depth can be further analyzed. The PP waves and SS waves are superimposed to improve the signal-to-noise ratio and resolution of the signal. By analyzing the waveforms and arrival time information after superposition, more accurate P-wave and S-wave velocities can be obtained. By using tomography technology or inversion methods, the P-wave and S-wave layer velocities at different depths can be obtained. According to the results of the velocity analysis, the relationship between the P-wave and S-wave velocities and depth can be established. These relationships are usually expressed as velocity-depth curves or velocity-depth models.

[0060] In this embodiment, after receiving the second reflected wave, static correction and noise removal are performed on the second reflected wave to remove the secondary shear wave, the primary longitudinal wave reflection wave and the longitudinal wave conversion wave in the second reflected wave.

[0061] S12. Reconstruct the downgoing wavefield based on the seismic shear wave and the velocity of the seismic shear wave, and reconstruct the upgoing wavefield of the reflected wave based on the velocity of the second reflected wave and the seismic longitudinal wave; image the downgoing wavefield and the upgoing wavefield of the reflected wave using the prestack depth migration technology to generate an initial image.

[0062] In this embodiment, pre-stack depth migration is a processing technology for achieving the spatial repositioning of geological structures. The pre-stack depth migration technology first requires the reconstruction of the wave field. This includes two main parts: the wave field of the downward propagation and the wave field of the reflected wave propagation upward. Downward wave field: This is the pressure or particle velocity field generated by the earthquake source and propagated underground. It represents the process of seismic waves propagating from the earthquake source to all directions underground. Upward wave field of reflected wave: This is the upward propagating reflected energy recorded by the ground. When seismic waves encounter the interface between different media underground, reflection and scattering will occur. These reflected waves will propagate toward the ground and be recorded by ground detectors.

[0063] In this embodiment, since this scheme performs superposition processing through PP waves and SS waves to improve the signal-to-noise ratio and resolution of the signal, more accurate longitudinal wave velocity and shear wave velocity can be obtained by analyzing the waveform and arrival time information after superposition. Based on the more accurate longitudinal wave velocity and shear wave velocity, more accurate downgoing wave field and reflected wave upgoing wave field can be established.

[0064] In this embodiment, prestack depth migration technology, based on wavefield reconstruction, applies imaging conditions such as cross-correlation to further process seismic data. Cross-correlation processing: Cross-correlation is a mathematical method used to measure the similarity between two signals. In seismic data processing, information about the subsurface model can be obtained by cross-correlating seismic data from different gathers. Imaging conditions: Cross-correlation imaging conditions state that when two wavefields (downgoing and upgoing) meet at a certain point underground and satisfy a certain phase relationship, that point can be considered a reflection point. By imaging all points that meet this condition, an image of the underground geological structure can be obtained. Finally, stacking is performed to achieve in-phase stacking of the reflection coefficients of the subsurface medium for imaging. Stacking: In seismic data processing, stacking is a common method used to improve the signal-to-noise ratio and resolution. By stacking seismic data from multiple gathers, signals from the same reflection point can be strengthened, while signals from different reflection points can be weakened or eliminated. In-phase stacking imaging: In prestack depth migration, in-phase stacking refers to stacking signals from the same reflection point with the same phase. This further improves imaging accuracy and resolution. Through in-phase stacking imaging, clearer and more accurate images of underground geological structures can be obtained.

[0065] Prestack depth migration first reconstructs the wavefields of the downgoing wavefield and the upgoing reflected wavefield. Using imaging conditions such as cross-correlation, the in-phase superposition of the reflection coefficients of the subsurface medium is achieved through superposition. Shear wave velocity is used to reconstruct the downgoing wavefield, while compressional wave velocity is used to reconstruct the upgoing reflected wavefield. This results in SP-wave conversion migration, as expressed by the following expression:

[0066]

[0067] d represents the downgoing wave field, u represents the upgoing wave field of the reflected wave, Vp and Vs represent the P-wave and S-wave velocities respectively, Δ represents the Laplace operator, g(t) represents the seismic S-wave, m(x) represents the second reflected wave, and t represents the time of wave field numerical calculation. Represents the sign of the partial derivative, x represents the spatial position, T represents the total duration of the seismic data, and I(x,z) represents imaging.

[0068] S13. Extracting the incident angle imaging gather of the seismic trace from the initial imaging, and determining the critical reflection angle of the seismic trace according to the wave velocity of the seismic shear wave and the wave velocity of the seismic longitudinal wave.

[0069] In this embodiment, the angle of incidence is defined as the angle between the wave field propagation and the formation normal. The incident angle track set arranges the imaged seismic traces in the order of the incident angle. Since the imaging of the same imaging point comes from the superposition of different seismic traces, the imaging traces arranged at different incident angles represent the contribution to the imaging point from the incident angle. The track set reflects the contribution of data in different incident angle ranges to the imaging point.

[0070] The critical reflection angle in this step is the critical reflection angle of the longitudinal wave reflection wave of the seismic shear wave at each imaging point in the initial imaging. This scheme performs imaging through the longitudinal wave reflection wave of the seismic shear wave. After determining the critical reflection angle of the seismic trace in this step, it can be determined that when the incident angle is greater than the critical reflection angle, no longitudinal wave reflection wave can be generated. Therefore, if the longitudinal wave reflection wave can still be detected, it can be explained that the longitudinal wave reflection wave is noise or abnormal data, and the abnormal data can be eliminated to improve the imaging quality.

[0071] Specifically, the seismic traces of the initial imaging can be obtained and arranged in the order of the incident angle to form an incident angle imaging trace set; for each imaging point in the initial imaging, the reflection critical angle of the longitudinal wave reflection wave of the seismic shear wave in the seismic trace at the imaging point is calculated based on the wave velocity and longitudinal wave velocity of the seismic shear wave at the imaging point; wherein, when the incident angle of the seismic shear wave is greater than the reflection critical angle, the longitudinal wave reflection wave cannot be generated; the critical angle distribution of the initial imaging is generated by combining the reflection critical angles of each imaging point.

[0072] In this embodiment, according to Snell's law, the magnitude of the incident angle and the reflection angle are related to the medium velocity, and the law is as follows:

[0073]

[0074] Since Vp>Vs, when the incident angle is greater than a certain value, θ2 will not exist. This angle is called the critical angle. Since the SP conversion wave is from a low-speed medium to a high-speed medium, when it is greater than the critical angle, there will be no SP conversion wave.

[0075] Using Vs and Vp, we can find the critical angle distribution of the imaging space. The critical angle satisfies the following formula:

[0076]

[0077] S14. Compare the incident angle of the seismic trace in the incident angle imaging gather with the critical reflection angle, determine the noise in the incident angle imaging gather based on the comparison result, and remove the noise from the incident angle imaging gather; perform stacking processing on the incident angle imaging gather after the noise is removed to obtain a stacked image.

[0078] In this embodiment, the imaging beyond the critical angle does not satisfy Snell's law and can be regarded as noise. For the angle domain gather of SP converted wave imaging, the critical angle distribution is used to perform excision processing on the imaging gather, such as Figure 7 As shown, the critical angle is applied to cut the rake angle gather, as Figure 8 The corner gathers are shown with critical angle removal applied.

[0079] In this embodiment, the gathers after critical angle removal are stacked to obtain the processed stacked image, such as Figure 9 As shown, the superimposed imaging section before resection is applied, such as Figure 10 Shown are superimposed imaging sections after resection.

[0080] In this embodiment, the present disclosure performs geological exploration by exciting seismic shear waves and seismic longitudinal waves, obtains shear wave reflections and longitudinal wave reflections of the seismic shear waves and seismic longitudinal waves, and thereby determines the velocity of the seismic shear waves and the velocity of the seismic longitudinal waves, reconstructs the downgoing wavefield by the velocity of the seismic shear waves, reconstructs the upgoing wavefield of the reflected waves by the velocity of the seismic longitudinal waves, and performs imaging based on the downgoing wavefield and the upgoing wavefield of the reflected waves, obtains the critical angle distribution of the imaging space by the velocity of the seismic shear waves and the velocity of the seismic longitudinal waves, determines the noise in the shear wave conversion wave incident angle gather by the critical angle, and re-superimposes the image after removing the noise in the gather. The shear wave conversion wave incident angle gather is processed by the critical angle to achieve efficient spatial variation constraint processing, exclude noise from the superimposed image, and improve the imaging quality of the shear wave conversion wave migration.

[0081] See also Figure 11 , Figure 11 The present invention provides an imaging system based on reflection waves, which includes: a seismic wave acquisition module 11, a wave velocity determination module 12, an imaging processing module 13 and a critical angle calculation module 14.

[0082] In this embodiment, the seismic wave acquisition module 11 is used to obtain the shear wave reflection wave of the seismic shear wave in the area to be explored as the first reflection wave, the longitudinal wave reflection wave of the seismic shear wave as the second reflection wave, and the longitudinal wave reflection wave of the seismic longitudinal wave as the third reflection wave.

[0083] In this embodiment, the wave velocity determination module 12 is used to determine the wave velocity of the seismic shear wave according to the first reflection wave, and to determine the wave velocity of the seismic longitudinal wave according to the third reflection wave.

[0084] In this embodiment, the imaging processing module 13 is used to reconstruct the downgoing wavefield based on the seismic shear wave and the wave velocity of the seismic shear wave, and to reconstruct the upgoing wavefield of the reflected wave based on the wave velocity of the second reflected wave and the seismic longitudinal wave; and the downgoing wavefield and the upgoing wavefield of the reflected wave are imaged and processed by the pre-stack depth migration technology to generate initial imaging.

[0085] In this embodiment, the critical angle calculation module 14 is used to extract the incident angle imaging gathers of the seismic traces from the initial imaging, and determine the reflection critical angle of the seismic traces according to the wave velocities of the seismic shear wave and the seismic longitudinal wave.

[0086] In this embodiment, the imaging processing module 13 is also used to compare the incident angle of the seismic trace in the incident angle imaging gather with the critical reflection angle, determine the noise in the incident angle imaging gather based on the comparison result, and remove the noise from the incident angle imaging gather; and perform stacking processing on the incident angle imaging gather after the noise is removed to obtain a stacked imaging.

[0087] In this embodiment, the imaging system further includes: a shear wave excitation source module for exciting seismic shear waves; and a longitudinal wave excitation source module for exciting seismic longitudinal waves.

[0088] In this embodiment, the seismic wave acquisition module 11 is specifically used to acquire first seismic data; acquire shear wave reflection waves of the first seismic data in the horizontal and vertical directions as first reflection waves; and acquire longitudinal wave reflection waves of the seismic data in the vertical direction as second reflection waves.

[0089] In this embodiment, the seismic wave acquisition module 11 is specifically configured to acquire the second seismic data; and acquire the longitudinal wave reflection wave of the second seismic data in the vertical direction as the third reflection wave.

[0090] In this embodiment, the critical angle calculation module 14 is specifically used to obtain the seismic traces of the initial imaging and arrange them in the order of the incident angle to form an incident angle imaging trace set; for each imaging point in the initial imaging, the reflection critical angle of the longitudinal wave reflection wave of the seismic shear wave in the seismic trace at the imaging point is calculated based on the wave velocity and longitudinal wave velocity of the seismic shear wave at the imaging point; wherein, when the incident angle of the seismic shear wave is greater than the reflection critical angle, the longitudinal wave reflection wave cannot be generated; and the critical angle distribution of the initial imaging is generated by integrating the reflection critical angles of each imaging point.

[0091] In this embodiment, the system further includes: a data preprocessing module for performing static correction and denoising on the second reflected wave, and removing the secondary shear wave, the primary longitudinal wave reflection wave and the longitudinal wave conversion wave in the second reflected wave.

[0092] like Figure 12 As shown, an embodiment of the present invention provides an electronic device, including a processor 1110, a communication interface 1120, a memory 1130 and a communication bus 1140, wherein the processor 1110, the communication interface 1120, and the memory 1130 communicate with each other through the communication bus 1140;

[0093] Memory 1130, for storing computer programs;

[0094] The processor 1110 is configured to implement any of the above imaging methods when executing the program stored in the memory 1130 .

[0095] The electronic device provided by the embodiment of the present invention, the processor 1110 obtains the shear wave reflection wave of the seismic shear wave in the area to be explored as the first reflection wave, the longitudinal wave reflection wave of the seismic shear wave as the second reflection wave, and the longitudinal wave reflection wave of the seismic longitudinal wave as the third reflection wave by executing the program stored in the memory 1130; and determines the velocity of the seismic shear wave according to the first reflection wave, and determines the velocity of the seismic longitudinal wave according to the third reflection wave; reconstructs the downlink wave field based on the seismic shear wave and the velocity of the seismic shear wave, and reconstructs the uplink wave field based on the velocity of the second reflection wave and the velocity of the seismic longitudinal wave. traveling wave field; imaging the downgoing wave field and the upgoing wave field of the reflected wave through the prestack depth migration technology to generate an initial image; extracting the incident angle imaging gather of the seismic trace from the initial image, and determining the reflection critical angle of the seismic trace according to the wave velocity of the seismic shear wave and the wave velocity of the seismic longitudinal wave; comparing the incident angle of the seismic trace in the incident angle imaging gather with the reflection critical angle, determining the noise in the incident angle imaging gather according to the comparison result, and removing the noise from the incident angle imaging gather; performing stacking processing on the incident angle imaging gather after removing the noise to obtain a stacked image.

[0096] The communication bus 1140 mentioned in the electronic device can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The communication bus 1140 can be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, the figure shows only one thick line, but this does not mean that there is only one bus or only one type of bus.

[0097] The communication interface 1120 is used for communication between the electronic device and other devices.

[0098] The memory 1130 may include a random access memory 1130 (RAM) or a non-volatile memory 1130, such as at least one disk storage 1130. Alternatively, the memory 1130 may be at least one storage device located away from the processor 1110.

[0099] The above-mentioned processor 1110 can be a general-purpose processor 1110, including a central processing unit 1110 (CPU), a network processor 1110 (NP), etc.; it can also be a digital signal processor 1110 (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0100] An embodiment of the present invention provides a computer-readable storage medium, which stores one or more programs. The one or more programs can be executed by one or more processors 1110 to implement the imaging method of any of the above embodiments.

[0101] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0102] Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. An imaging method based on reflected waves, characterized in that: The method comprises: Acquire a shear wave reflection of a seismic shear wave in the area to be explored as a first reflection wave, a longitudinal wave reflection of the seismic shear wave as a second reflection wave, and a longitudinal wave reflection of the seismic longitudinal wave as a third reflection wave; and determine a velocity of the seismic shear wave based on the first reflection wave, and determine a velocity of the seismic longitudinal wave based on the third reflection wave; reconstructing a downgoing wavefield based on the seismic shear wave and its velocity, and reconstructing an upgoing wavefield of the reflected wave based on the second reflected wave and its velocity, and performing imaging processing on the downgoing wavefield and the upgoing wavefield of the reflected wave using a prestack depth migration technique to generate an initial image; Extracting an incident angle imaging gather of a seismic trace from the initial imaging, and determining a critical reflection angle of the seismic trace according to the wave velocity of the seismic shear wave and the wave velocity of the seismic longitudinal wave; The incident angle of the seismic trace in the incident angle imaging gather is compared with the critical reflection angle, the noise in the incident angle imaging gather is determined according to the comparison result, and the noise is removed from the incident angle imaging gather; and the incident angle imaging gather after the noise removal is stacked to obtain a stacked imaging.

2. The imaging method according to claim 1, wherein The method of obtaining a shear wave reflection of a seismic shear wave in the area to be explored as a first reflection wave, a longitudinal wave reflection of a seismic shear wave as a second reflection wave, and a longitudinal wave reflection of a seismic longitudinal wave as a third reflection wave comprises: Exciting seismic shear waves through a shear wave excitation source to obtain first seismic data; acquiring a shear wave reflection wave of the first seismic data in a horizontal direction as a first reflection wave; Acquiring a longitudinal wave reflection wave of the seismic data in a vertical direction as a second reflection wave; Exciting seismic longitudinal waves through a longitudinal wave excitation source to obtain second seismic data; A longitudinal wave reflection wave of the second seismic data in the vertical direction is obtained as a third reflection wave.

3. The imaging method according to claim 1, wherein Extracting the incident angle imaging gather of the seismic trace from the initial imaging, and determining the critical reflection angle of the seismic trace according to the wave velocity of the seismic shear wave and the wave velocity of the seismic longitudinal wave, comprises: Acquire the seismic traces of the initial imaging and arrange them in the order of incident angles to form the incident angle imaging trace gather; For each imaging point in the initial imaging, a critical reflection angle of a longitudinal wave reflection of the seismic shear wave in the seismic trace at the imaging point is calculated based on the seismic shear wave velocity and the longitudinal wave velocity of the seismic shear wave at the imaging point; wherein when the incident angle of the seismic shear wave is greater than the critical reflection angle, no longitudinal wave reflection wave is generated; The critical angle distribution of the initial imaging is generated by integrating the reflection critical angles of various imaging points.

4. The imaging method according to any one of claims 1 to 3, characterized in that: The method further comprises: Static correction and denoising are performed on the second reflected wave to remove the secondary shear wave, the primary longitudinal wave reflected wave and the longitudinal wave converted wave in the second reflected wave.

5. An imaging system based on reflected waves, characterized in that: The imaging system comprises: A seismic wave acquisition module, configured to acquire a shear wave reflection of a seismic shear wave in a to-be-explored area as a first reflection wave, a longitudinal wave reflection of a seismic shear wave as a second reflection wave, and a longitudinal wave reflection of a seismic longitudinal wave as a third reflection wave; a wave velocity determination module, configured to determine the wave velocity of the seismic shear wave according to the first reflected wave, and determine the wave velocity of the seismic longitudinal wave according to the third reflected wave; an imaging processing module, configured to reconstruct a downgoing wavefield based on the seismic shear wave and its velocity, and to reconstruct an upgoing wavefield of the reflected wave based on the second reflected wave and its velocity; and to perform imaging processing on the downgoing wavefield and the upgoing wavefield of the reflected wave using a prestack depth migration technique to generate an initial image; A critical angle calculation module is used to extract the incident angle imaging gather of the seismic trace from the initial imaging, and determine the reflection critical angle of the seismic trace according to the wave velocity of the seismic shear wave and the wave velocity of the seismic longitudinal wave; The imaging processing module is further used to compare the incident angle of the seismic trace in the incident angle imaging gather with the critical reflection angle, determine the noise in the incident angle imaging gather based on the comparison result, and remove the noise from the incident angle imaging gather; and obtain a stacked image by stacking the incident angle imaging gather after noise removal.

6. The imaging system according to claim 5, characterized in that The imaging system further comprises: a shear wave excitation source module for exciting seismic shear waves; and a longitudinal wave excitation source module for exciting seismic longitudinal waves; The seismic wave acquisition module is specifically used to acquire first seismic data; acquire a shear wave reflection wave of the first seismic data in the horizontal direction as a first reflection wave; and acquire a longitudinal wave reflection wave of the seismic data in the vertical direction as a second reflection wave; The seismic wave acquisition module is specifically used to acquire second seismic data; and acquire a longitudinal wave reflection wave of the second seismic data in a vertical direction as a third reflection wave.

7. The imaging system according to claim 5, wherein: A critical angle calculation module is specifically used to obtain the seismic traces of the initial imaging and arrange them in the order of incident angle to form the incident angle imaging trace set; for each imaging point in the initial imaging, the reflection critical angle of the longitudinal wave reflection wave of the seismic shear wave in the seismic trace at the imaging point is calculated based on the wave velocity and longitudinal wave velocity of the seismic shear wave at the imaging point; wherein, when the incident angle of the seismic shear wave is greater than the reflection critical angle, the longitudinal wave reflection wave cannot be generated; and the critical angle distribution of the initial imaging is generated by comprehensively analyzing the reflection critical angles of each imaging point.

8. The imaging system according to any one of claims 5 to 7, characterized in that: The system further includes a data preprocessing module for performing static correction and denoising on the second reflected wave, and removing the secondary shear wave, the primary longitudinal wave reflected wave and the longitudinal wave converted wave from the second reflected wave.

9. An electronic device, characterized in that: include: processor; as well as A memory storing computer executable instructions which, when executed, cause the processor to perform the method according to any one of claims 1 to 4.

10. A computer storage medium, characterized in that in, The computer storage medium stores one or more programs, and when the one or more programs are executed by a processor, the method according to any one of claims 1 to 4 is implemented.

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