Viscous sound medium angle gather extraction method based on adaptive beam reverse time migration

Abstract

The invention relates to the technical field of geological exploration in the petroleum industry, in particular to a viscous-acoustic medium angle gather extraction method based on self-adaptive wave beam reverse time migration. According to the method, the self-adaptive beam operator depending on local space velocity change is introduced to realize automatic focusing of the seismic beam, and the absorption attenuation effect caused by the viscosity is compensated through the viscous sound medium during complex value travel; slowness information of a shot point is extracted based on travel time information of a self-aggregation seismic beam, a reflection field angle at an imaging point position is further calculated, an imaging value is located at a correct position according to the range and interval of the reflection field angle, and direct extraction of a viscous sound medium angle gather is achieved. According to the method, the absorption attenuation effect caused by the viscosity of the medium can be effectively compensated, the high-quality angle gather can be output, the calculation efficiency and the calculation precision are both achieved, and powerful support is provided for migration velocity analysis and oil reservoir description work of the viscous medium.

Description

Technical Field

[0001] This invention relates to the field of geological exploration technology in the petroleum industry, specifically to a method for extracting angle gathers of viscous acoustic media based on adaptive beamback time-shifting. Background Technology

[0002] As an effective tool for imaging complex structures and regions with strong lateral velocity variations, pre-stack depth migration can output imaging results and also obtain incompletely stacked imaging gathers. Unstacked seismic gathers contain rich information on subsurface lithology and velocity. Angled gathers, as artifact-free gathers, map the relationship between local incident angles and the spatial location of imaging points. They can be used for AVO and AVA analyses and provide strong support for migration velocity analysis and stacked imaging. Numerous studies have shown that viscosity is widespread in subsurface media; ignoring its influence can lead to problems such as imaging position deviation, underestimation of amplitude, and reduced resolution, seriously affecting subsequent interpretation. Therefore, researching angled gather extraction algorithms suitable for viscous acoustic media is of great significance for obtaining high-precision imaging profiles and tomographic velocity modeling.

[0003] Currently, mainstream angle gather extraction algorithms are mainly based on ray theory. They calculate travel time, amplitude, and phase information through kinematic and dynamic ray tracing, which is well-suited for complex observation systems and features flexibility, efficiency, and high angular resolution. The Kirchhoff algorithm is a representative example in the industry. However, due to the limitations of asymptotic ray theory, it suffers from insufficient adaptability to complex structures.

[0004] Seismic beamforming algorithms are an improved type of ray-based algorithm that uses independent seismic beams to characterize seismic wave propagation, incorporating richer dynamic information and handling multiple arrivals. Wave-based algorithms, based on numerical solutions to the wave equation, can not only handle multiple arrivals but also preserve amplitude information well; a representative example is reverse time migration imaging. However, due to limitations in the accuracy, computational load, and storage requirements of complex wavefield calculations, research on angle gather extraction algorithms is relatively limited, especially for complex media such as anisotropic and viscous media.

[0005] Invention patent CN103472481B discloses a method for extracting angle gathers using GPU inverse time migration. The method includes the following steps: (1) forward extension of the shot point wave field; (2) parallel execution of inverse time migration and angle information statistics; (3) angle gather extraction. This method is mainly used for fast and stable extraction of angle gathers.

[0006] Patent application CN107329169A discloses a method for extracting angle gathers. The method includes: acquiring seismic data and velocity data, and determining the incident angle of a ray based on the seismic data and the velocity data; determining the Fresnel band width of the ray based on the velocity data and preset ray parameters; interpolating and weighting the seismic data within the Fresnel band width, and using the interpolation and weighting result as the angle gather corresponding to the incident angle. This method can improve the extraction quality of angle gathers, thereby improving the imaging effect of angle overlay profiles and increasing the analysis accuracy of AVA (Advanced Visual Aspect Ratio).

[0007] Invention patent CN103472481B discloses a method for extracting angle gathers by performing reverse time migration using a GPU. The method includes the following steps: (1) forward extension of the shot point wavefield; (2) parallel execution of reverse time migration and angle information statistics; (3) angle gather extraction; Step (1) includes the following steps: (A1) placing an artificial wavelet source at the shot point location; (A2) using the finite difference method to perform forward extension of the wavefield of the seismic wave excited by the artificial wavelet source in step (A1) along the time direction to obtain the shot point wavefield at different times; Step (A2) is completed on a GPU; In step (2), the reverse time migration includes the following steps: (B1) storing the shot point wavefields obtained in step (A2) at different times in a wavefield data buffer pool; (B2) extending the shot point wavefields obtained in step (A2) forward along the time direction to the maximum time to obtain the wavefield at the maximum time of the shot point; forward extension refers to extending the wavefield along the direction of increasing time; (B3) reading the wavefield at the maximum time of the receiver from the seismic data collected in the field, and then starting from the maximum time, extending the shot point wavefield and the receiver wavefield backward along the time direction to obtain the wavefields at different times of the shot point and the receiver; backward extension Topography refers to extending the wavefield along the direction of decreasing time; (B4) Multiply the wavefield at the shot point and the wavefield at the receiver point at each time step to obtain the imaging result; (B5) Each shot point corresponds to a single shot, and the imaging result described in step (B4) for each single shot is stored separately on the disk as a single-shot migration imaging result; (B6) Each seismic data acquired from the field contains many single shots, and the imaging result described in step (B4) for each single shot is used to perform multi-shot stacking to obtain a multi-shot stacked migration imaging result; the multi-shot stacking refers to accumulating the imaging values ​​of multiple single-shot imaging results at the same location underground. In step (2), the angle information statistics include the following steps: (C1) Angle information statistics: the shot point wavefields in the wavefield data buffer are stored in chronological order, and the amplitude and propagation angle at each spatial location at each moment are extracted; (C2) After completing step (A2), the propagation angle at the moment of maximum amplitude of the shot point wavefield at each spatial location obtained in step (C1) is stored on the disk as an angle information data body; (C3) On the multi-shot superimposed migration imaging results obtained in step (B6), the dip angle is extracted as a dip angle information data body and stored on the disk. This method is mainly used for fast and stable extraction of angle gathers.

[0008] There are few reports on improving the accuracy of angle gather extraction in viscous acoustic media in the current technology. Summary of the Invention

[0009] The main objective of this invention is to provide a method for extracting angle gathers in viscous acoustic media based on adaptive beamback time-shifting. This method effectively combines the high efficiency of ray-based algorithms with the high precision of wave-based algorithms, providing strong support for subsequent velocity analysis and angle-by-angle superposition imaging of viscous acoustic media.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] This invention provides a method for extracting angle gathers in viscous acoustic media based on adaptive beamback time migration. The method includes the following steps: acquiring preprocessed shot records, migration velocity fields, and Q-value parameter fields; determining the frequency band range, maximum ray exit angle, reflection angle range, and interval, and constructing an angle gather index; calculating seismic wave travel time, path, and amplitude using ray tracing; constructing an adaptive seismic beam to achieve automatic beamwidth focusing; compensating for absorption attenuation effects and constructing Green's function and forward and reverse extended wavefields; obtaining single-shot imaging values ​​based on cross-correlation conditions; calculating the reflection angle of the imaging point based on adaptive beamback time and reducing the imaging values; performing iterative calculations on all shot records and superimposing them to obtain the final migration profile and angle gathers.

[0012] Furthermore, it is necessary to obtain the observation system, total number of shots, recording duration and interval of the preprocessed shot records, and select scaling operators in the horizontal and vertical directions for smoothing based on the offset velocity field grid information.

[0013] Furthermore, at the shot point and receiver point, the fourth-order Runge-Kunta method is used to solve the partial differential equations of kinematic and dynamic ray tracing of the isotropic medium based on the maximum ejection angle and ray parameter interval, so as to obtain the seismic wave travel time, path and amplitude.

[0014] Among them, the ray parameter interval is calculated based on the frequency band range and the average velocity of the velocity field:

[0015]

[0016] Where f min and f max These are the lowest and highest frequencies, respectively, v avg The average velocity of the velocity field;

[0017] Furthermore, an adaptive beam operator is constructed based on the plane wave and spherical wave solutions obtained from dynamic ray tracing and the local spatial velocity, as shown in the following equation:

[0018]

[0019] Where [p1,q1] and [p2,q2] are the plane wave and spherical wave solutions of the dynamic ray tracing equation, L(s) is the waist width of the seismic wave beam, and v(s) is the seismic wave velocity;

[0020] Substituting the above adaptive beamforming operator into the Gaussian beam expression, we obtain the expression for adaptive seismic beamforming to achieve automatic seismic beam focusing:

[0021] U(s,n,ω)=Aexp(iωT) (3)

[0022]

[0023] Where ε(s0) and v(s0) are the initial point adaptive beam operator and velocity, respectively, and A and T are the complex amplitude and travel time of the adaptive beam, respectively.

[0024] Furthermore, the complex travel time of the viscous acoustic medium is used to replace the complex travel time of the adaptive seismic beam, and the relevant imaginary terms are negatively evaluated for absorption attenuation compensation.

[0025] At the shot point and receiver point, adaptive seismic beams with different ray parameters are used to extend downwards, and weighted superposition integration is performed based on the energy contribution of different beams to construct the Green function.

[0026] The forward extended wavefield can be obtained by superimposing and integrating the Green's functions at the shot point; at the receiver point, the reverse extended wavefield can be obtained by superimposing and integrating Green's functions with different ray parameters through Kirchhoff integration.

[0027] Furthermore, the complex travel time of the viscous acoustic medium is as follows:

[0028]

[0029] Where t(s) is the travel time of the acoustic medium, t Q For travel time dependent on the Q-value field; and for t Q The relevant items are negative.

[0030] Furthermore, the constructed Green's function is shown in the following equation:

[0031]

[0032] Where θ is the emission angle and p is the slowness vector.

[0033] Furthermore, the positively extended wave field at the shot point is shown in the following equation:

[0034]

[0035] Where f(ω) is the Fourier transform of the seismic wavelet;

[0036] Reverse extended wave field at the receiver point:

[0037]

[0038] Where U(x,t) is the seismic record at the receiving point.

[0039] Furthermore, the single-shot imaging value is calculated based on the cross-correlation condition of the forward extended wavefield at the shot point and the reverse extended wavefield at the receiver point in the time direction:

[0040] I(x0,x s )=∫U B (x0,t0)U F (x0,t;x s )dt0 (9).

[0041] Furthermore, the method for calculating the reflection angle of the imaging point:

[0042] The travel time of a point R near the ray can be expressed by the travel time of a point X on the ray:

[0043]

[0044] Where n is the distance from point R to point X, it has the following form:

[0045] n = (xx X )t z -(zz X )t x (11)

[0046] Where t x and t z These are the horizontal and vertical components of the tangent vector under the coordinates of the ray center;

[0047] Take the partial derivatives of both sides of equation (10) for x and z respectively, and denote them as follows: At this point:

[0048]

[0049] The reflection angle can be obtained from the aforementioned slowness component.

[0050]

[0051] By assigning the imaging value to the correct position in the angle gather based on the location of the underground imaging point and the gather index information corresponding to the reflection angle, the extraction of the single-shot angle gather can be achieved.

[0052] The present invention also provides an apparatus for extracting angle gathers of adhesive acoustic media based on adaptive beamback time-shifting. The apparatus includes at least one processor and a memory communicatively connected to the at least one processor. The memory stores instructions which are executed by the at least one processor to enable the at least one processor to implement the method for extracting angle gathers of adhesive acoustic media based on adaptive beamback time-shifting as described in claim 1.

[0053] The present invention also provides a readable storage medium storing computer-executable instructions for causing a computer to perform the method for extracting angle gathers of viscous acoustic media based on adaptive beam time-shifting as described in claim 1.

[0054] Compared with the prior art, the present invention has the following advantages:

[0055] This invention achieves automatic focusing of seismic beams by introducing an adaptive beam operator that depends on local spatial velocity changes, and compensates for the absorption attenuation effect caused by viscosity by using the complex travel time of the viscous acoustic medium. Furthermore, it extracts the slowness information of the shot receiver based on the travel time information of the self-aggregated seismic beams, calculates the reflection angle at the imaging point, and repositions the imaging values ​​to the correct position according to the range and interval of the reflection angle, thus realizing the direct extraction of the angle gather of the viscous acoustic medium.

[0056] The method described in this invention can not only effectively compensate for the absorption attenuation effect caused by the viscosity of the medium, but also output high-quality angle gathers, combining computational efficiency and accuracy, providing strong support for the migration velocity analysis of viscous media and reservoir characterization. Attached Figure Description

[0057] Figure 1 The following are the operational steps of a method for extracting angle gathers from adhesive acoustic media;

[0058] Figure 2 Schematic diagram of the model's velocity field and Q-value parameter field (left: velocity field; right: Q-value field);

[0059] Figure 3 This is a schematic diagram of a single-shot seismic record.

[0060] Figure 4 The following is a comparative diagram of the imaging results (left: acoustic adaptive beam reverse time migration imaging result; right: acoustic adaptive beam reverse time migration imaging result of Example 2).

[0061] Figure 5 A comparative diagram of the angle gather at CDP 925 (left: acoustic adaptive beam time-shift extraction gather; right: adaptive beam time-shift extraction gather after absorption attenuation compensation in Example 2). Detailed Implementation

[0062] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0063] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0064] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0065] Example 1

[0066] A method for extracting angle gathers in viscous acoustic media based on adaptive beamback time-shifting, the method comprising the following steps:

[0067] (1) Obtain the preprocessed shot record, offset velocity field and Q-value parameter field;

[0068] The observation system, total number of shots, recording duration and interval of the shot record are obtained, and scale operators are selected in the horizontal and vertical directions for smoothing based on the offset velocity field grid information.

[0069] (2) Determine the frequency band, maximum emission angle of the ray, reflection angle range and interval, and construct an angle gather index; the frequency band range is 5Hz to 50Hz, the maximum emission angle of the ray is 60°, the reflection angle range is 0° to 60°, with an interval of 2°. Determine the number of reflection angles based on the reflection angle range and interval, and construct an angle gather index by combining the horizontal and vertical grid points of the velocity field.

[0070] (3) At the shot point and receiver point, ray tracing is performed to calculate the seismic wave travel time, path and amplitude based on the maximum ray exit angle and parameter interval;

[0071] First, calculate the ray parameter interval based on the frequency band range and the average velocity of the velocity field:

[0072]

[0073] Where f min and f max These are the lowest and highest frequencies, respectively, v avg The average velocity of the velocity field.

[0074] At the shot point and receiver point, the fourth-order Runge-Kunta method is used to solve the partial differential equations of kinematic and dynamic ray tracing for isotropic media based on the maximum ejection angle and ray parameter interval, so as to obtain the seismic wave travel time, path and amplitude.

[0075] (4) Based on local spatial seismic wave velocity, construct adaptive seismic beams to achieve automatic beamwidth focusing;

[0076] Based on the plane wave and spherical wave solutions and local spatial velocities derived from dynamic ray tracing, the following adaptive beam operator is constructed:

[0077]

[0078] Where [p1,q1] and [p2,q2] are the plane wave and spherical wave solutions of the dynamic ray tracing equation, L(s) is the waist width of the seismic wave beam, and v(s) is the seismic wave velocity.

[0079] Substituting the above adaptive beam operator into the Gaussian beam expression, we obtain the adaptive seismic beam expression:

[0080] U(s,n,ω)=Aexp(iωT) (3)

[0081]

[0082] Where ε(s0) and v(s0) are the initial point adaptive beam operator and velocity, respectively, and A and T are the complex amplitude and travel time of the adaptive beam, respectively.

[0083] The adaptive seismic beamwidth automatically focuses according to changes in local spatial velocity, effectively improving the imaging accuracy of complex structures while ensuring the propagation pattern of seismic waves.

[0084] (5) The absorption attenuation effect is compensated based on the complex travel time of the viscoacous medium, and the weighted integral of the adaptive seismic beam with different exit angles is used to construct the Green function and the forward and reverse extended wave fields.

[0085] The complex travel time of the viscous acoustic medium is used to replace the complex travel time of the adaptive seismic beam, and the relevant imaginary terms are negative to compensate for the attenuation effect caused by the viscosity of the underground medium.

[0086] The complex travel time of the adhesive acoustic medium is shown in the following equation:

[0087]

[0088] Where t(s) is the travel time of the acoustic medium, t Q For the travel time dependent on the Q-value field; replace the complex travel time in equation (4) with the above equation, and for tQ By taking the negative sign of the relevant terms, viscosity can be compensated.

[0089] At the shot and receiver locations, adaptive seismic beams with different ray parameters are used for downward extension, and a weighted superposition integration is performed based on the energy contributions of different beams to construct the Green's function.

[0090]

[0091] Where θ is the emission angle and p is the slowness vector.

[0092] The positively extended wavefield can be obtained by superimposing and integrating the Green's function at the shot point:

[0093]

[0094] Where f(ω) is the Fourier transform of the seismic wavelet.

[0095] At the receiver point, the reverse extended wavefield is obtained by superimposing and integrating Green's functions with different ray parameters using Kirchhoff integrals:

[0096]

[0097] Where U(x,t) is the seismic record at the receiving point.

[0098] (6) Obtain single-shot imaging values ​​based on the cross-correlation between the forward extended wave field at the shot point and the reverse extended wave field at the receiver point;

[0099] I(x0,x s )=∫U B (x0,t0)U F (x0,t;x s )dt0 (9)

[0100] (7) Calculate the reflection angle of the imaging point based on the real-valued travel time of the adaptive seismic beam, and reduce the imaging value according to the index;

[0101] The travel time of a point R near the ray can be expressed by the travel time of a point X on the ray:

[0102]

[0103] Where n is the distance from point R to point X, it has the following form:

[0104] n = (xx X )t z -(zz X )t x (11)

[0105] Where tx and t z These are the horizontal and vertical components of the tangent vector at the coordinates of the ray center.

[0106] Take the partial derivatives of both sides of equation (10) for x and z respectively, and denote them as follows: At this point:

[0107]

[0108] The reflection angle can be obtained from the aforementioned slowness component.

[0109]

[0110] By assigning the imaging value to the correct position in the angle gather based on the location of the underground imaging point and the gather index information corresponding to the reflection angle, the extraction of the single-shot angle gather can be achieved.

[0111] (8) Perform cyclic calculations on all shot records and superimpose them to obtain the final offset profile and angle gather.

[0112] Example 2

[0113] Using the Hess model, angle gather extraction processing for adhesive acoustic media was performed according to the method described in Example 1:

[0114] In step (1), the input velocity field and Q-value parameter field are... Figure 2 ) and gun records ( Figure 3 The model has 1501 horizontal and 351 vertical grid points, with a spacing of 10m. The seismic records are synthesized by the pseudospectral method, using a full reception method, with 3001 time sampling points and an interval of 1ms.

[0115] Step (2): Based on the information such as the shot record and velocity field grid, determine that the frequency band range used for offset is 5Hz to 50Hz, the maximum emission angle of the ray is 60°, the reflection angle range is 0° to 60°, the interval is 1°, and the memory required for the angle gather is 4*1501*351*60 / 10243GB.

[0116] Step (3): The ray parameter interval calculated according to Equation (1) is 0.0000395. Combined with the maximum ray emission angle, the kinematic and dynamic ray tracing equations are solved at the shot point and receiver point using the fourth-order Runge-Kunta method to calculate the travel time, path and amplitude of the seismic wave.

[0117] Step (4): Based on the plane wave and spherical wave solutions of the dynamic ray equation and the local spatial velocity, construct an adaptive beam operator and substitute it into the Gaussian beam expression to construct an adaptive seismic beam, thereby achieving automatic focusing of the beamwidth;

[0118] Step (5): The complex travel time of the viscous acoustic medium in equation (5) is used to replace the complex travel time in equation (4), and t is calculated. Q The relevant terms are negative to compensate for the absorption attenuation effect, and on this basis, the Green function and the forward and reverse extended wave fields are constructed;

[0119] Step (6): Calculate the cross-correlation between the forward propagation wave field at the shot point and the reverse extension wave field at the receiver point according to equation (9) to obtain the single-shot imaging value.

[0120] Step (7): Calculate the horizontal and vertical slowness shown in Equation (11) based on the adaptive beam real-value travel time relationship between the center ray point and nearby points shown in Equation (10). Then, calculate the reflection angle based on Equation (12). Finally, construct an index using the imaging point position and the reflection angle to locate the imaging value at the correct position in the angle gather.

[0121] Step (8) involves iteratively calculating the 240 shot data, superimposing the imaging values ​​and angle gathers, and finally obtaining the offset profile and angle gathers.

[0122] Depend on Figure 4 As can be seen, due to neglecting the influence of viscosity, the energy in the subsalt region is weak, and the continuity and focusing of the phase axis are also poor in the acoustic adaptive beamback imaging results. However, in the imaging results of this invention, the deep energy is effectively recovered, and the continuity and focusing of the phase axis are also greatly improved. Figure 5 The image shows the angle gather extracted at the CDP925 location. Comparison reveals that the angle gather extracted by this invention is generally flattened, with a more uniform deep energy distribution and more focused and continuous in-phase axes.

[0123] in, Figure 4 The adaptive beamback time migration profile of the medium acoustic wave is obtained by constructing the Green function and the forward and reverse extended wave fields based on the complex travel time of Equation (4), and then performing cross-correlation imaging. Figure 5 The angle gather extracted by the adaptive beamback time-shifting of the medium acoustic wave is obtained by calculating the propagation angle based on the real-valued travel time information of Equation (4) and reducing the imaging value, without compensating for the absorption attenuation effect caused by viscosity.

[0124] Example 3

[0125] An apparatus for extracting angle gathers of adhesive acoustic media based on adaptive beamback time-shifting is disclosed. The apparatus includes at least one processor and a memory communicatively connected to the at least one processor. The memory stores instructions which are executed by the at least one processor to enable the at least one processor to implement the angle gather extraction method for adhesive acoustic media based on adaptive beamback time-shifting as described in Embodiment 1.

[0126] A readable storage medium storing computer-executable instructions for causing a computer to perform the adhesive acoustic medium angle gather extraction method based on adaptive beamback time-shifting as described in Embodiment 1.

[0127] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for extracting angle gathers in viscous acoustic media based on adaptive beamback time-shifting, characterized in that, include: The process involves acquiring preprocessed shot records, migration velocity fields, and Q-value parameter fields; determining the frequency band range, maximum ray exit angle, reflection angle range, and interval; constructing an angle gather index; calculating seismic wave travel time, path, and amplitude using ray tracing; constructing an adaptive seismic beam to achieve automatic beamwidth focusing; compensating for absorption attenuation effects; constructing Green's function and forward and reverse extended wavefields; obtaining single-shot imaging values ​​based on cross-correlation conditions; calculating the reflection angle of imaging points based on adaptive beam travel time and reducing the imaging values; performing iterative calculations on all shot records and superimposing them to obtain the final migration profile and angle gather.

2. The method according to claim 1, characterized in that, It is necessary to obtain the observation system, total number of shots, recording duration and interval of the preprocessed shot records, and select scale operators in the horizontal and vertical directions for smoothing based on the offset velocity field grid information.

3. The method according to claim 1, characterized in that, At the shot point and receiver point, the fourth-order Runge-Kunta method is used to solve the partial differential equations of kinematic and dynamic ray tracing of the isotropic medium based on the maximum ejection angle and ray parameter interval, so as to obtain the seismic wave travel time, path and amplitude. Among them, the ray parameter interval is calculated based on the frequency band range and the average velocity of the velocity field: Where f min and f max These are the lowest and highest frequencies, respectively, v avg The average velocity of the velocity field.

4. The method according to claim 1, characterized in that, An adaptive beam operator is constructed based on the plane wave and spherical wave solutions and local spatial velocities using dynamic ray tracing, as shown in the following equation: Where [p1,q1] and [p2,q2] are the plane wave and spherical wave solutions of the dynamic ray tracing equation, L(s) is the waist width of the seismic wave beam, and v(s) is the seismic wave velocity; Substituting the above adaptive beamforming operator into the Gaussian beam expression, we obtain the expression for adaptive seismic beamforming to achieve automatic seismic beam focusing: U(s,n,ω)=Aexp(iωT) (3) Where ε(s0) and v(s0) are the initial point adaptive beam operator and velocity, respectively, and A and T are the complex amplitude and travel time of the adaptive beam, respectively.

5. The method according to claim 1, characterized in that, The complex travel time of the viscous acoustic medium is used to replace the complex travel time of the adaptive seismic beam, and the relevant imaginary terms are negative to compensate for absorption attenuation. At the shot point and receiver point, adaptive seismic beams with different ray parameters are used to extend downwards, and weighted superposition integration is performed based on the energy contribution of different beams to construct the Green function. The forward extended wavefield can be obtained by superimposing and integrating the Green's functions at the shot point; at the receiver point, the reverse extended wavefield can be obtained by superimposing and integrating Green's functions with different ray parameters through Kirchhoff integration.

6. The method according to claim 5, characterized in that, The complex travel time of the adhesive acoustic medium is shown in the following equation: Where t(s) is the travel time of the acoustic medium, t Q For travel time dependent on the Q-value field; and for t Q The relevant items are negative.

7. The method according to claim 5, characterized in that, The constructed Green's function is shown in the following equation: Where θ is the emission angle and p is the slowness vector.

8. The method according to claim 5, characterized in that, The positively extended wave field at the shot point is shown in the following equation: Where f(ω) is the Fourier transform of the seismic wavelet; Reverse extended wave field at the receiver point: Where U(x,t) is the seismic record at the receiving point.

9. The method for extracting angle gathers from adhesive acoustic media according to claim 1, characterized in that, The single-shot imaging value is calculated based on the cross-correlation condition of the forward extended wavefield at the shot point and the reverse extended wavefield at the receiver point in the time direction: I(x0,x s )=∫U B (x0,t0)U F (x0,t;x s )dt0 (9)。 10. The method for extracting angle gathers from adhesive acoustic media according to claim 1, characterized in that, Method for calculating the reflection angle of the imaging point: The travel time of a point R near the ray can be expressed by the travel time of a point X on the ray: Where n is the distance from point R to point X, it has the following form: n=(x-x X )t z -(z-z X )t x (11) Where t x and t z These are the horizontal and vertical components of the tangent vector under the coordinates of the ray center; Take the partial derivatives of both sides of equation (10) for x and z respectively, and denote them as follows: At this point: The reflection angle can be obtained from the aforementioned slowness component. By assigning the imaging value to the correct position in the angle gather based on the location of the underground imaging point and the gather index information corresponding to the reflection angle, the extraction of the single-shot angle gather can be achieved.

11. A device for extracting angle gathers in viscous acoustic media based on adaptive beamback time-shifting, characterized in that, It includes at least one processor and a memory communicatively connected to the at least one processor; wherein the memory stores instructions that are executed by the at least one processor to enable the at least one processor to implement the adhesive acoustic medium angle gather extraction method based on adaptive beam counter-time offset as described in claim 1 when executing the instructions.

12. A readable storage medium, characterized in that, The readable storage medium stores computer-executable instructions for causing a computer to perform the adhesive acoustic medium angle gather extraction method based on adaptive beam counter-time offset as described in claim 1.

Images