Azimuthal anisotropic first-arrival ray tracing method, device, equipment and medium
By performing grid discretization and wavefront scanning search on the HTI medium and tracing the azimuthally anisotropic first-arrival ray path, the problem of the inability to accurately characterize the azimuthally anisotropic velocity field in the existing technology is solved, and an accurate description of the near-surface velocity distribution is achieved.
Patent Information
- Application Number
- CN202311252532.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-26
- Publication Date
- 2025-09-12
- Estimated Expiration
- 2043-09-26
AI Technical Summary
Existing technologies are unable to accurately characterize the characteristics of azimuthally anisotropic velocity fields, resulting in large differences in tomographic inversion results in different azimuths, which affects the description of near-surface velocity distribution.
A method for tracing first-arrival ray with azimuthal anisotropy is provided. By performing grid discretization on the HTI medium, the ray group angle and length are determined. An azimuthal anisotropic velocity model is constructed based on the preset work area data, and the first-arrival ray path is traced using a wavefront scanning search algorithm.
The adaptability of first-arrival ray tracing technology has been improved, and it can accurately describe the ray path in large-offset and wide-azimuth data, eliminate the influence of surface anisotropy, and establish a more accurate near-surface velocity model.
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Figure CN119716994B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of first-arrival ray tracing, and in particular to a method for tracing first-arrival ray with azimuthally anisotropic first-arrival ray, a device for tracing first-arrival ray with azimuthally anisotropic top-arrival ray, an electronic device and a computer-readable storage medium. Background Art
[0002] With the continuous increase in exploration efforts, the exploration targets are getting deeper and deeper, the height difference in the work area is getting larger and larger, and the lateral changes in shallow velocity are becoming more and more dramatic; with the continuous development of new acquisition technologies, the proportion of three-dimensional seismic data collected with large offsets and wide azimuths is increasing.
[0003] The anisotropic characteristics are reflected in these data. In many work areas, it has been found that there are obvious differences in the shallow velocity models inverted from first arrivals at different azimuths. The differences in the low-velocity part are particularly obvious and directly affect the imaging effect.
[0004] However, in the existing technology, the ray path obtained only by isotropic first-arrival ray tracing cannot accurately characterize the characteristics of the azimuthally anisotropic velocity field, resulting in large differences in the results of tomographic inversion in different azimuths and an inability to better describe the near-surface velocity distribution.
[0005] How to better utilize large-offset, wide-azimuth seismic data to complete the anisotropy investigation and modeling of refraction waves, eliminate the influence of surface anisotropy, and establish a more accurate near-surface velocity model is an issue that needs to be addressed urgently. Summary of the Invention
[0006] The purpose of the present invention is to provide a method, device, equipment and medium for tracing azimuthally anisotropic first arrival rays, so as to at least solve the problem that the existing technology cannot accurately characterize the characteristics of the azimuthally anisotropic velocity field.
[0007] In order to achieve the above object, the present invention provides, on the one hand, a method for tracing azimuthally anisotropic first arrival rays, the method comprising:
[0008] Performing grid discretization processing on the HTI medium to obtain an HTI rectangular area, wherein the HTI rectangular area includes a plurality of rectangular units, and each rectangular unit includes a plurality of rays;
[0009] Determine the group angle and length of each ray within the rectangular unit of the receiving point;
[0010] The preset work area data and the group angle of each ray corresponding to the receiving point are input into a pre-built azimuthally anisotropic velocity initial model to obtain the ray group velocity of the rectangular unit of the receiving point. The preset work area data includes: HTI medium azimuth angle, symmetry axis axis, HTI medium anisotropy parameter and vertical velocity;
[0011] Determine the travel time of the rectangular unit at the receiving point based on the ray group velocity and the length of each ray at the receiving point;
[0012] Based on the wavefront scanning search algorithm, the first arrival ray path is traced according to the travel time of the rectangular unit of the receiving point.
[0013] Preferably, based on a wavefront scanning search algorithm, the path of the first arrival ray is tracked according to the travel time of the rectangular unit of the receiving point, including:
[0014] Perform wavefront scanning on the HTI rectangular area and determine the minimum travel time of all rectangular cells based on the travel time of the rectangular cells at the receiving point;
[0015] Search for the first arrival ray path based on the minimum travel time of all rectangular cells.
[0016] Preferably, the method further comprises: constructing an initial azimuthal anisotropic velocity model, comprising:
[0017] Determine the anisotropic Thomsen parameters of VTI media;
[0018] Performing coordinate axis transformation on the HTI medium and the VTI medium to obtain a transformation result, wherein the transformation result includes: anisotropic Thomsen parameters of the HTI medium and a transformation relationship between the HTI medium and the VTI medium;
[0019] An initial azimuthal anisotropic velocity model is constructed based on the conversion results.
[0020] Preferably, the azimuthal anisotropic velocity initial model for:
[0021] ;
[0022] Where, is the vertical velocity, is the conversion formula between HTI medium and VTI medium, is the first anisotropy parameter of the VTI medium, which is used to characterize the longitudinal anisotropy strength. is the second anisotropy parameter of VTI medium.
[0023] Preferably, the conversion relationship between the HTI medium and the VTI medium is:
[0024] ;
[0025] Where, is the axial direction of symmetry, is the azimuth angle of the HTI medium, is the angle between the incident ray and the vertical.
[0026] Preferably, the anisotropic Thomsen parameters of the HTI medium include: a first anisotropic parameter of the HTI medium, and the calculation expression of the first anisotropic parameter of the HTI medium is:
[0027] ;
[0028] Where, is the first anisotropic parameter of HTI medium, is the first anisotropy parameter of the VTI medium.
[0029] Preferably, the anisotropic Thomsen parameter of the HTI medium further includes: a second anisotropic parameter of the HTI medium, and the calculation expression of the second anisotropic parameter of the HTI medium is:
[0030] ;
[0031] Where, is the second anisotropy parameter of HTI medium, is the second anisotropy parameter of the VTI medium, f is the frequency;
[0032] in, , where is the shear wave velocity.
[0033] On the other hand, the present invention further provides an azimuthally anisotropic first-arrival ray tracing device for implementing the above-mentioned azimuthally anisotropic first-arrival ray tracing method, the device comprising:
[0034] a discrete processing module, configured to perform grid discrete processing on the HTI medium to obtain an HTI rectangular area, wherein the HTI rectangular area includes a plurality of rectangular units, and each rectangular unit includes a plurality of rays;
[0035] A ray determination module is used to determine the group angle and length of each ray within the rectangular unit of the receiving point;
[0036] A velocity determination module is configured to input preset work area data and the group angle of each ray corresponding to the receiving point into a pre-built azimuthally anisotropic velocity initial model to obtain the ray group velocity of the rectangular unit at the receiving point. The preset work area data includes: the HTI medium azimuth angle, the axial direction of the symmetry axis, the HTI medium anisotropy parameter, and the vertical velocity.
[0037] A travel time determination module, for determining the travel time of the rectangular unit at the receiving point based on the ray group velocity of the rectangular unit at the receiving point and the length of each ray;
[0038] The ray tracing module is used to trace the first arrival ray path according to the travel time of the rectangular unit of the receiving point based on the wavefront scanning search algorithm.
[0039] On the other hand, the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and runnable on the processor, wherein the processor implements the above-mentioned azimuthal anisotropic first-arrival ray tracing method when executing the computer program.
[0040] On the other hand, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which implements the above-mentioned azimuthally anisotropic first-arrival ray tracing method when executed by a processor.
[0041] Through the above technical solution, the present invention has at least the following technical effects:
[0042] The present invention can improve the adaptability of the first-arrival wave ray tracing technology. In the acquisition area of large offset and wide azimuth data, it has the characteristics of azimuthal anisotropy, can more accurately describe the ray path of the first-arrival wave, and plays a key role in the near-surface anisotropy modeling.
[0043] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:
[0045] Figure 1 This is a flow chart of an azimuthally anisotropic first-arrival ray tracing method provided by one embodiment of the present invention;
[0046] Figure 2 is a schematic diagram of an HTI rectangular area provided by one embodiment of the present invention;
[0047] Figure 3 This is a schematic diagram of moving from one node to another in a uniform medium within a HTI rectangular area provided by an embodiment of the present invention;
[0048] Figure 4 It is a block diagram of an azimuthally anisotropic first-arrival ray tracing device provided by one embodiment of the present invention. DETAILED DESCRIPTION
[0049] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.
[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.
[0051] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.
[0052] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.
[0053] Example 1
[0054] Figure 1 is a flow chart of an azimuthally anisotropic first-arrival ray tracing method provided by one embodiment of the present invention, such as Figure 1 As shown, this embodiment provides an azimuthally anisotropic first-arrival ray tracing method, the method comprising:
[0055] Step S101: performing grid discretization processing on the HTI medium to obtain an HTI rectangular area, wherein the HTI rectangular area includes a plurality of rectangular units, and each rectangular unit includes a plurality of rays.
[0056] In this embodiment, the HTI medium is discretized into (m*n*l) adjacent rectangular units of the same size through a grid, and the velocity in each unit is uniform, such as Figure 2 and Figure 3 shown.
[0057] In the subsequent azimuthal anisotropic ray tracing process, starting from a known travel time point (such as the source point), the minimum travel time and ray direction information are gradually calculated according to the Fermat principle; let Q be the set of known travel time points q, p be the unknown travel time point adjacent to it, t q , t p are the minimum travel times of points q and p, respectively, and t pqis the minimum travel time from q to p (local travel time), r is the position of the secondary source of p (the intersection of the ray passing through point p and the wavefront), then:
[0058] ;
[0059] According to Huygens' principle, q only needs to traverse the boundaries of Q (i.e., wavefront points). When the minimum travel times of all neighboring wavefront points are found, these points become new wavefront points.
[0060] Step S102: Determine the group angle and length of each ray within the rectangular unit of the receiving point.
[0061] exist Figure 3 In the geometric relationship of the ray path at the receiving point, the group angle corresponding to the ray path can be calculated ; The length of the ray is the length of the ray experienced in the current grid (the rectangular unit corresponding to the receiving point) .
[0062] Step S103: Input the preset work area data and the group angle of each ray corresponding to the receiving point into the pre-built azimuthal anisotropic velocity initial model to obtain the ray group velocity of the rectangular unit of the receiving point; wherein the preset work area data includes: HTI medium azimuthal angle, symmetry axis axial direction, HTI medium anisotropy parameter and vertical velocity.
[0063] In this embodiment, the method further includes: constructing an initial azimuthal anisotropic velocity model, including:
[0064] Step a01: Determine the anisotropic Thomsen parameters of the VTI medium;
[0065] Step a02: performing coordinate axis transformation on the HTI medium and the VTI medium to obtain a transformation result, wherein the transformation result includes: anisotropic Thomsen parameters of the HTI medium and a transformation relationship between the HTI medium and the VTI medium;
[0066] Step a03: Construct an initial azimuthal anisotropic velocity model based on the conversion results.
[0067] Among them, the initial model of azimuthal anisotropic velocity for:
[0068] (1);
[0069] Where, is the vertical velocity, is the conversion formula between HTI medium and VTI medium, is the first anisotropy parameter of the VTI medium, which is used to characterize the longitudinal anisotropy strength. is the second anisotropy parameter of VTI medium.
[0070] The conversion relationship between the HTI medium and the VTI medium is:
[0071] (2);
[0072] Where, is the axial direction of symmetry, is the azimuth angle of the HTI medium, is the angle between the incident ray and the vertical.
[0073] The anisotropic Thomsen parameters of the HTI medium include: a first anisotropic parameter of the HTI medium, and the calculation expression of the first anisotropic parameter of the HTI medium is:
[0074] (3);
[0075] Where, is the first anisotropic parameter of HTI medium, is the first anisotropy parameter of the VTI medium.
[0076] The anisotropic Thomsen parameter of the HTI medium further includes a second anisotropic parameter of the HTI medium. The calculation expression of the second anisotropic parameter of the HTI medium is:
[0077] (4);
[0078] Where, is the second anisotropy parameter of HTI medium, is the second anisotropy parameter of the VTI medium, f is the frequency;
[0079] in, , where is the shear wave velocity.
[0080] In this embodiment, the anisotropic parameters of the HTI medium include: the second anisotropic parameter of the HTI medium and the first anisotropic parameter of the HTI medium. Based on the actual working condition data of the receiving point, the preset working area data can be obtained, that is, the HTI medium azimuth angle, the axial direction of the symmetry axis, the anisotropic parameter of the HTI medium, and the vertical velocity.
[0081] When the anisotropy parameters of the HTI medium, the azimuth angle of the HTI medium, the axial direction of the symmetry axis, the anisotropy parameters of the HTI medium and the vertical velocity are known, the group angle corresponding to the ray path will be calculated. As , the group velocity of the current grid can be calculated according to formula (1). The group velocity of each ray in the same grid unit is the same.
[0082] Step S104: determining the travel time of the rectangular unit at the receiving point according to the ray group velocity of the rectangular unit at the receiving point and the length of each ray.
[0083] Therefore, according to the ray length experienced in the current grid (rectangular unit corresponding to the receiving point) Dividing by the group velocity of the current grid can be calculated according to formula (1), the travel time of all wavefront points on the current grid boundary can be obtained. Since the current grid takes into account the rectangular cells adjacent to the grid, the travel time of the wavefront neighbor corresponding to each wavefront point is the minimum travel time among the travel times of all wavefront points in the grid cells.
[0084] Step S105: Based on the wavefront scanning search algorithm, the first arrival ray path is tracked according to the travel time of the rectangular unit of the receiving point.
[0085] In this embodiment, based on the wavefront scanning search algorithm, the first arrival ray path is tracked according to the travel time of the rectangular unit of the receiving point, including:
[0086] Step b01: Perform wavefront scanning on the HTI rectangular area and determine the minimum travel time of all rectangular cells based on the travel time of the rectangular cells at the receiving point;
[0087] Step b02: Search for the first arrival ray path based on the minimum travel time of all rectangular cells.
[0088] The wavefront scanning of the HTI rectangular area is:
[0089] Let the source point (i.e. Figure 2 The travel time at the excitation location in the image is zero, while the travel time at all nodes except the source is infinite. First, select a scan center, O, and a square centered at O with r as half its side length as the scan square. Now, increase r by 1, gradually expanding the scan square across the entire HTI rectangular area. Nodes on the top, bottom, left, and right boundaries of each scan square are considered wavefront points. For each wavefront point, calculate the minimum travel time of its neighboring points. Then, narrow the scan square from the HTI rectangular area boundary toward the scan center, scanning from the outside inward to calculate the first-arrival travel time and ray paths at all nodes.
[0090] When searching for the first arrival ray path, since each rectangular unit has a certain wavefront point travel time and position on its edge, the ray path from any point to the source point can be found. If the receiving point (i.e. Figure 2), then take the receiving point as the starting point and find the corresponding secondary source coordinates in sequence until the source point ends. Since each secondary source coordinate records the minimum travel time, the searched path is the minimum travel time path, that is, the first arrival ray path.
[0091] In this embodiment, based on the group velocity at any position and the first arrival ray path, the minimum travel time of any shot pair traveling through the anisotropic velocity field and anisotropic field path can be calculated, thus preparing data for anisotropic multi-parameter inversion.
[0092] This embodiment can improve the adaptability of the first-arrival wave ray tracing technology. For the near-surface with azimuthal anisotropy in the collection area of large offset and wide azimuth data, it can more accurately describe the ray path of the first-arrival wave, and plays a key role in the near-surface anisotropy modeling.
[0093] Example 2
[0094] Figure 4 is a block diagram of an azimuthally anisotropic first-arrival ray tracing device provided by one embodiment of the present invention, such as Figure 4 As shown, based on the same inventive concept as in the first embodiment, this embodiment further provides an azimuthally anisotropic first-arrival ray tracing device for implementing the azimuthally anisotropic first-arrival ray tracing method of the first embodiment, the device comprising:
[0095] a discrete processing module, configured to perform grid discrete processing on the HTI medium to obtain an HTI rectangular area, wherein the HTI rectangular area includes a plurality of rectangular units, and each rectangular unit includes a plurality of rays;
[0096] A ray determination module is used to determine the group angle and length of each ray within the rectangular unit of the receiving point;
[0097] A velocity determination module is configured to input preset work area data and the group angle of each ray corresponding to the receiving point into a pre-built azimuthally anisotropic velocity initial model to obtain the ray group velocity of the rectangular unit at the receiving point. The preset work area data includes: the HTI medium azimuth angle, the axial direction of the symmetry axis, the HTI medium anisotropy parameter, and the vertical velocity.
[0098] A travel time determination module, for determining the travel time of the rectangular unit at the receiving point based on the ray group velocity of the rectangular unit at the receiving point and the length of each ray;
[0099] The ray tracing module is used to trace the first arrival ray path according to the travel time of the rectangular unit of the receiving point based on the wavefront scanning search algorithm.
[0100] Based on the same inventive concept as embodiment 1, this embodiment also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and runnable on the processor, wherein the processor implements the above-mentioned azimuthal anisotropic first-arrival ray tracing method when executing the computer program.
[0101] Based on the same inventive concept as in the first embodiment, this embodiment further provides a computer-readable storage medium storing a computer program, which implements the above-mentioned azimuthally anisotropic first-arrival ray tracing method when executed by a processor.
[0102] This embodiment can improve the adaptability of the first-arrival wave ray tracing technology. For the near-surface with azimuthal anisotropy in the collection area of large offset and wide azimuth data, it can more accurately describe the ray path of the first-arrival wave, and plays a key role in the near-surface anisotropy modeling.
[0103] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0104] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.
[0105] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.
[0106] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.
[0107] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.
[0108] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.
[0109] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can be implemented using any method or technology to store information. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change RAM (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media such as modulated data signals and carrier waves.
[0110] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.
[0111] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.
Claims
1. A method for tracing azimuthally anisotropic first arrival rays, characterized in that: The method comprises: Performing grid discretization processing on the HTI medium to obtain an HTI rectangular area, wherein the HTI rectangular area includes a plurality of rectangular units, and each rectangular unit includes a plurality of rays; Determine the group angle and length of each ray within the rectangular unit of the receiving point; The preset work area data and the group angle of each ray corresponding to the receiving point are input into a pre-built azimuthally anisotropic velocity initial model to obtain the ray group velocity of the rectangular unit of the receiving point. The preset work area data includes: HTI medium azimuth angle, symmetry axis axis, HTI medium anisotropy parameter and vertical velocity; Determine the travel time of the rectangular unit at the receiving point based on the ray group velocity and the length of each ray at the receiving point; Based on the wavefront scanning search algorithm, the first arrival ray path is traced according to the travel time of the rectangular unit of the receiving point.
2. The method according to claim 1, characterized in that Based on the wavefront scanning search algorithm, the first arrival ray path is tracked according to the travel time of the rectangular unit of the receiving point, including: Perform wavefront scanning on the HTI rectangular area and determine the minimum travel time of all rectangular cells based on the travel time of the rectangular cells at the receiving point; Search for the first arrival ray path based on the minimum travel time of all rectangular cells.
3. The method according to claim 1, characterized in that The method further includes: constructing an initial azimuthal anisotropic velocity model, including: Determine the anisotropic Thomsen parameters of VTI media; Performing coordinate axis transformation on the HTI medium and the VTI medium to obtain a transformation result, wherein the transformation result includes: anisotropic Thomsen parameters of the HTI medium and a transformation relationship between the HTI medium and the VTI medium; An initial azimuthal anisotropic velocity model is constructed based on the conversion results.
4. The method according to claim 3, characterized in that The initial model of azimuthal anisotropic velocity for: ; Where, is the vertical velocity, is the conversion formula between HTI medium and VTI medium, is the first anisotropy parameter of the VTI medium, which is used to characterize the longitudinal anisotropy strength. is the second anisotropy parameter of VTI medium.
5. The method according to claim 4, characterized in that The conversion relationship between the HTI medium and the VTI medium is: ; Where, is the axial direction of symmetry, is the azimuth angle of the HTI medium, is the angle between the incident ray and the vertical.
6. The method according to claim 4, characterized in that The anisotropic Thomsen parameters of the HTI medium include: a first anisotropic parameter of the HTI medium, and the calculation expression of the first anisotropic parameter of the HTI medium is: ; Where, is the first anisotropic parameter of HTI medium, is the first anisotropy parameter of the VTI medium.
7. The method according to claim 6, characterized in that The anisotropic Thomsen parameter of the HTI medium also includes: a second anisotropic parameter of the HTI medium. The calculation expression of the second anisotropic parameter of the HTI medium is: ; Where, is the second anisotropy parameter of HTI medium, is the second anisotropy parameter of the VTI medium, f is the frequency; in, , where is the shear wave velocity.
8. An azimuthally anisotropic first-arrival ray tracing device for implementing the azimuthally anisotropic first-arrival ray tracing method according to any one of claims 1 to 7, characterized in that: The device comprises: a discrete processing module, configured to perform grid discrete processing on the HTI medium to obtain an HTI rectangular area, wherein the HTI rectangular area includes a plurality of rectangular units, and each rectangular unit includes a plurality of rays; A ray determination module is used to determine the group angle and length of each ray within the rectangular unit of the receiving point; A velocity determination module is configured to input preset work area data and the group angle of each ray corresponding to the receiving point into a pre-built azimuthally anisotropic velocity initial model to obtain the ray group velocity of the rectangular unit at the receiving point. The preset work area data includes: the HTI medium azimuth angle, the axial direction of the symmetry axis, the HTI medium anisotropy parameter, and the vertical velocity. A travel time determination module, for determining the travel time of the rectangular unit at the receiving point based on the ray group velocity of the rectangular unit at the receiving point and the length of each ray; The ray tracing module is used to trace the first arrival ray path according to the travel time of the rectangular unit of the receiving point based on the wavefront scanning search algorithm.
9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the azimuthally anisotropic first-arrival ray tracing method according to any one of claims 1 to 7 is implemented.
10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the azimuthally anisotropic first-arrival ray tracing method according to any one of claims 1 to 7 is implemented.
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