Reflected wave-based imaging method and system, electronic equipment and storage medium

Abstract

The invention relates to an imaging method and system based on reflected waves, electronic equipment and a storage medium. The imaging method comprises the following steps: acquiring a first reflected wave, a second reflected wave and a third reflected wave; the wave velocities of the seismic transverse waves and the seismic longitudinal waves are determined; reconstructing a downlink wave field and a reflected wave uplink wave field; performing imaging processing on the downlink wave field and the reflected wave uplink wave field to generate an initial image; extracting an incident angle imaging gather of the seismic trace from the initial image, and determining a reflection critical angle of the seismic trace according to the wave velocity of the seismic transverse wave and the wave velocity of the seismic longitudinal wave; and 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, cutting off the noise from the incident angle imaging gather, and then carrying out superposition processing to obtain a superposition image. A transverse wave converted wave incident angle gather is processed through a critical angle, efficient constraint processing of space change is achieved, noise is eliminated outside a superposed image, and the imaging quality of transverse wave converted wave migration is improved.

Description

Technical Field

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

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

[0003] When encountering a medium interface with different density and elastic modulus during the propagation of seismic waves, shear waves may also be converted into longitudinal waves, which are called shear wave conversion waves. These seismic waves can also be used for imaging, providing more comprehensive information for a comprehensive understanding of underground media. However, in the process of realizing conversion wave imaging, it is difficult to achieve accurate wave field separation because the three-component wave generator used for field data collection and the propagation direction of seismic waves are not strictly consistent, which causes crosstalk noise in the imaging and affects the imaging quality. Summary of the invention

[0004] To solve the above problems, the present invention provides an imaging method, system, electronic device and storage medium based on reflection waves. The incident angle gathers of shear-wave conversion waves are processed by critical angle to achieve efficient spatial variation constraint processing, exclude noise from the stacked image, and improve the imaging quality of shear-wave conversion wave migration.

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

[0006] Acquire 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 velocity of the seismic shear wave according to the first reflection wave, and determine the velocity of the seismic longitudinal wave according to the third reflection wave;

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

[0008] Extracting incident angle imaging gathers of 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;

[0009] The incident angle of the seismic trace in the incident angle imaging gather is compared with the reflection critical 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, the method of obtaining 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 includes:

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

[0012] Acquire 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 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:

[0017] The seismic traces obtained from the initial imaging are arranged in the order of incident angles to form the incident angle imaging trace gathers;

[0018] For each imaging point in the initial imaging, a critical reflection angle of a 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 critical reflection angle, no longitudinal wave reflection wave can be 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, used for acquiring 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;

[0024] A wave velocity determination module, used 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 is used to reconstruct a downgoing wave field based on the seismic shear wave and the wave velocity of the seismic shear wave, and to reconstruct an upgoing wave field of the reflected wave based on the second reflected wave and the wave velocity of the seismic longitudinal wave; and to perform imaging processing on the downgoing wave field and the upgoing wave field of the reflected wave by using a prestack depth migration technique to generate an initial image;

[0026] A critical angle calculation module, used for extracting the incident angle imaging gather of the seismic trace from the initial imaging, 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;

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

[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 a horizontal direction as a first reflection wave; and acquire a longitudinal wave reflection wave of the seismic data in a vertical direction as a second reflection wave;

[0030] The seismic wave acquisition module is specifically used 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.

[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 according to 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 combining the reflection critical angles of each imaging point.

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

[0033] In order to solve the above technical problem, 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 executes 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 seismic shear waves and seismic longitudinal waves, and thereby determines the velocity of seismic shear waves and the velocity of seismic longitudinal waves, reconstructs the downgoing wave field by the velocity of seismic shear waves, reconstructs the upgoing wave field of reflection waves by the velocity of seismic longitudinal waves, and performs imaging based on the downgoing wave field and the upgoing wave field of reflection waves, obtains the critical angle distribution of the imaging space by the velocity of seismic shear waves and the velocity of seismic longitudinal waves, determines the noise in the incident angle gather of shear wave conversion waves by the critical angle, and re-superimposes the image after removing the noise in the gather. The incident angle gather of shear wave conversion waves is processed by the critical angle, so as to realize efficient spatial variation constraint processing, exclude noise from the superimposed image, and improve the imaging quality of shear wave conversion wave migration.

[0038] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. The purpose and other advantages of the present disclosure can be realized and obtained by the structures pointed out 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 diagram of a process flow 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 A schematic diagram of longitudinal wave velocity and depth according to an embodiment of the present disclosure is shown;

[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 front angle gather applying a critical angle cut according to an embodiment of the present disclosure is shown;

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

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

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

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

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

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0053] The same reference numerals in the drawings represent the same or similar elements, components or parts, and thus the repeated description 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 attributives representing the numbers may be used herein to describe various devices, elements, components or parts, these devices, elements, components or parts should not be limited by these attributives. In other words, these attributives are only used to distinguish one from another. For example, the first device may also be called the second device, but it 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. 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 carried out in the field based on geological survey and observation system design, and longitudinal wave excitation source and transverse wave excitation source are successively used to artificially excite transverse seismic waves and longitudinal seismic waves, and a three-component seismograph is arranged on the surface to receive seismic data. A three-component seismograph is an instrument for recording and analyzing ground vibrations, which can simultaneously detect components of seismic waves in three different directions (usually the horizontal X-axis, Y-axis 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, SV wave, vertical shear shear wave, SV wave is a wave in which the particle vibration occurs in a plane perpendicular to the wave propagation plane, SH wave, horizontal shear shear wave, SH wave is a wave in which the particle vibration occurs in a plane parallel to the wave propagation plane, and SS wave data is a type of seismic wave, usually referring to a certain specific form or path of shear wave (S wave) propagating in underground media. S wave is a shear wave, and its vibration direction is perpendicular to the propagation direction, as shown in FIG. Figure 2 Theoretically, there is no shear wave data in the Z-axis component. What is received is the shear wave conversion 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 after reflecting once on the surface, it still propagates to the measurement point in the form of longitudinal waves. 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 conversion wave among reflected shear wave (S wave) and transmitted shear wave, reflected longitudinal wave and 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. The propagation velocities of P-waves and S-waves can be preliminarily estimated by utilizing the arrival time information of the first arrival wave. The variation of velocity with depth can be further analyzed by comparing the arrival time of the first arrival wave at different shot offsets. The PP waves and SS waves are superimposed to improve the signal-to-noise ratio and resolution of the signal. More accurate P-wave and S-wave velocities can be obtained by analyzing the waveforms and arrival time information after superposition. The P-wave and S-wave layer velocities at different depths can be obtained by using tomography technology or inversion methods. According to the results of velocity analysis, the variation relationship between 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 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.

[0061] S12. Reconstruct the downgoing wave field based on the seismic shear wave and the velocity of the seismic shear wave, and reconstruct the upgoing wave field of the reflected wave based on the velocity of the second reflected wave and the seismic longitudinal wave; perform imaging processing on the downgoing wave field and the upgoing wave field of the reflected wave through the prestack depth migration technology to generate initial imaging.

[0062] In this embodiment, pre-stack depth migration is a processing technology to achieve the spatial relocation 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 wavefield: 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. Reflection wave upward wavefield: This is the reflected energy propagating upward recorded by the ground. When seismic waves encounter the interface of different underground media, reflection and scattering will occur. These reflected waves will propagate to 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, and more accurate downlink wave field and reflected wave uplink wave field can be established based on the more accurate longitudinal wave velocity and shear wave velocity.

[0064] In this embodiment, on the basis of wave field reconstruction, the prestack depth migration technology 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 of the underground model can be obtained by cross-correlation processing of seismic data of different gathers. Imaging condition: The cross-correlation imaging condition means that when two wave fields (downgoing wave field and upgoing wave field) meet at a certain point underground and meet a certain phase relationship, the point can be considered as a reflection point. By imaging all points that meet this condition, an image of the underground geological structure can be obtained. Finally, the in-phase superposition of the reflection coefficient of the underground medium is achieved by superposition for imaging. Superposition: In seismic data processing, superposition is a commonly used method for improving the signal-to-noise ratio and resolution of the signal. By superimposing seismic data of multiple gathers, the signal from the same reflection point can be strengthened, while the signal from different reflection points can be weakened or eliminated. In-phase stacking imaging: In prestack depth migration, in-phase stacking refers to superimposing signals from the same reflection point with the same phase. This can further improve the accuracy and resolution of imaging. Through in-phase stacking imaging, clearer and more accurate images of underground geological structures can be obtained.

[0065] Prestack depth migration first reconstructs the wave field of the downward propagation of the wave field and the upward propagation of the reflected wave, and applies imaging conditions such as cross-correlation to achieve in-phase superposition of the reflection coefficient of the underground medium for imaging. The shear wave velocity is used in the process of reconstructing the downward wave field, and the longitudinal wave velocity is used in the process of reconstructing the upward wave field of the reflected wave, that is, SP wave conversion wave migration is achieved, and its expression is as follows:

[0066]

[0067] d represents the downgoing wave field, u represents the upgoing wave field of the reflected wave, Vp and Vs represent the longitudinal and shear wave velocities respectively, Δ represents the Laplace operator, g(t) represents the seismic shear wave, m(x) represents the second reflected wave, and t represents the time of numerical calculation of the wave field. 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 track 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 definition of the incident angle is the angle between the wave field propagation and the formation normal. The incident angle track gather arranges the imaged seismic tracks in the order of the incident angle. Since the imaging of the same imaging point comes from the superposition of different seismic tracks, the imaging tracks arranged at different incident angles represent the contribution to the imaging point from the incident angle. The track gather reflects the contribution of data in different incident angle ranges to the imaging point.

[0070] The reflection critical angle in this step is the reflection critical 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 this step determines the reflection critical angle of the seismic trace, it can be determined that when the incident angle is greater than the reflection critical 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 according to 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, and this angle becomes the critical angle. Since the SP conversion wave belongs to the entry from the low-speed medium into the 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, comparing the incident angle of the seismic trace in the incident angle imaging gather with the critical reflection 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 stacked imaging.

[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 The critical angle is applied to cut the front angle gather as shown in Figure 8 The back-angle gather is shown with critical angle cutoff applied.

[0079] In this embodiment, the gathers after critical angle removal are stacked to obtain the processed stacked images, such as Fig. 9 The application of pre-resection superimposed imaging sections is shown, such as Fig.10 Shown are superimposed imaging sections after resection.

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

[0081] See also Fig.11 , Fig.11 The present invention provides an imaging system based on reflection waves, and the imaging system comprises: 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 acquire 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 to perform imaging processing on the downgoing wavefield and the upgoing wavefield of the reflected wave through 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 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.

[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 according to 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 the first seismic data; acquire the shear wave reflection waves of the first seismic data in the horizontal direction and the vertical direction as the first reflection wave; acquire the longitudinal wave reflection waves of the seismic data in the vertical direction as the second reflection wave.

[0089] In this embodiment, the seismic wave acquisition module 11 is specifically used 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 according to 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.

[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 reflected wave and the longitudinal wave converted wave in the second reflected wave.

[0092] like Fig.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, used for storing computer programs;

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

[0095] In 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 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; comparing the incident angle of the seismic trace in the incident angle imaging gather with the critical reflection 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 above electronic device can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The communication bus 1140 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or 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 may include a non-volatile memory 1130 (non-volatile memory), such as at least one disk memory 1130. Optionally, the memory 1130 may also 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 gates 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, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part 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, the process or function according to the embodiment of the present invention is generated in whole or in part. 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 a website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or a data center that includes one or more available media integrated. 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 hard disk SolidStateDisk (SSD)), etc.

[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 make the essence of the corresponding technical solutions 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 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 velocity of the seismic shear wave according to the first reflection wave, and determine the velocity of the seismic longitudinal wave according to the third reflection wave; Reconstructing a downgoing wave field based on the seismic shear wave and the wave velocity of the seismic shear wave, and reconstructing an upgoing wave field of the reflected wave based on the second reflected wave and the wave velocity of the seismic longitudinal wave; performing imaging processing on the downgoing wave field and the upgoing wave field of the reflected wave by using a prestack depth migration technique to generate an initial image; Extracting incident angle imaging gathers of 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; The incident angle of the seismic trace in the incident angle imaging gather is compared with the reflection critical 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, characterized in that: The method of obtaining 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 comprises: Exciting seismic shear waves through a shear wave excitation source to obtain first seismic data; Acquire 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, characterized in that: The step of 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: The seismic traces obtained from the initial imaging are arranged in the order of incident angles to form the incident angle imaging trace gathers; For each imaging point in the initial imaging, a critical reflection angle of a 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 critical reflection angle, no longitudinal wave reflection wave can be 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, used for acquiring 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; A wave velocity determination module, used 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 is used to reconstruct a downgoing wave field based on the seismic shear wave and the wave velocity of the seismic shear wave, and to reconstruct an upgoing wave field of the reflected wave based on the second reflected wave and the wave velocity of the seismic longitudinal wave; and to perform imaging processing on the downgoing wave field and the upgoing wave field of the reflected wave by using a prestack depth migration technique to generate an initial image; A critical angle calculation module, used for extracting the incident angle imaging gather of the seismic trace from the initial imaging, 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; The imaging processing module is also used to compare the incident angle of the seismic trace in the incident angle imaging gather with the reflection critical angle, determine the noise in the incident angle imaging gather according to the comparison result, and remove the noise from the incident angle imaging gather; and obtain a stacked imaging by stacking the incident angle imaging gather after removing the noise.

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

7. The imaging system according to claim 5, characterized in that: 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 according to 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 considering 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 comprises: a data preprocessing module, which is used 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.

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 1-4.

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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