A method and device for establishing a near-surface grid velocity model and an electronic device

Abstract

Embodiments of the present application provide a method and device for establishing a near-surface grid velocity model and an electronic device. The method for establishing the near-surface grid velocity model comprises: using a tomographic inversion technique, and according to first arrival time data picked up by shot points arranged in a target work area, establishing a first near-surface grid velocity model; determining a range of a source excitation point of the target work area according to coordinates of the shot points; dividing the first near-surface grid velocity model into an effective area and a boundary area according to the range of the source excitation point; and adjusting a velocity value of a grid in the boundary area according to a velocity value of a grid in the effective area, to obtain a second near-surface grid velocity model.

Description

Technical Field

[0001] This application relates to the field of seismic exploration technology, and in particular to a method, apparatus and electronic device for establishing a near-surface grid velocity model. Background Technology

[0002] As exploration progresses, the requirements for the accuracy of exploration targets become increasingly stringent. In recent years, high-resolution tomographic inversion has made significant progress, as this method can invert the changing trends of velocity models. The establishment of an accurate velocity model is a prerequisite for all high-precision seismic imaging, inversion, and interpretation exploration techniques. At the same time, the accuracy of the near-surface velocity model also plays a crucial role in static correction problems in complex areas.

[0003] First-arrival tomographic near-surface inversion is currently the most common method for establishing near-surface velocity models. This method can obtain a time-equivalent velocity model, providing a relatively realistic near-surface velocity model for true surface depth migration. However, among related techniques, the near-surface grid velocity model established based on tomographic inversion calculation theory has lower inversion accuracy in the boundary regions.

[0004] Therefore, how to establish a high-precision near-surface grid velocity model is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This application provides a method, apparatus, and electronic device for establishing a near-surface grid velocity model, used to establish a high-precision near-surface grid velocity model.

[0006] One embodiment of this application provides a method for establishing a near-surface grid velocity model. The method includes: using tomographic inversion technology, establishing a first near-surface grid velocity model based on first arrival time data picked up from shot receivers located in a target work area; determining the range of the seismic source excitation point in the target work area based on the coordinates of the shot receivers; dividing the first near-surface grid velocity model into an effective region and a boundary region based on the range of the seismic source excitation point; and adjusting the velocity values ​​of the grids in the boundary region based on the velocity values ​​of the grids within the effective region to obtain a second near-surface grid velocity model.

[0007] In some embodiments, there are unfilled grids with empty velocity values ​​within the boundary region; adjusting the velocity values ​​of the grids within the boundary region based on the velocity values ​​of the grids within the effective region includes: for each unfilled grid, performing the following operations: determining the velocity values ​​of grids within the effective region that are far from the unfilled grid within a preset search range and whose elevation value is less than a preset threshold, to obtain a first reference velocity value; in response to the number of the first reference velocity values ​​being greater than 0, obtaining the velocity value of the unfilled grid based on the first reference velocity values.

[0008] In some embodiments, obtaining the velocity value of the grid to be filled based on the first reference velocity value includes: obtaining the velocity value of the grid to be filled based on the average value of the first reference velocity value.

[0009] In some embodiments, the method further includes: in response to the number of the first reference velocity values ​​being 0, determining the velocity values ​​of grids within a valid region that are within a preset search range of the grid to be filled and whose depth direction index is the same as that of the grid to be filled, to obtain a second reference velocity value; and using an inverse distance weighted interpolation algorithm to obtain the velocity value of the grid to be filled based on the second reference velocity value.

[0010] In some embodiments, the method further includes: performing mean smoothing on the velocity values ​​of the grid within the boundary region according to a preset smoothing radius.

[0011] In some embodiments, the method further includes: slicing the boundary region along the periphery of the effective region to obtain a transition region; and adjusting the velocity value of the grid in the transition region using a linear interpolation algorithm.

[0012] In some embodiments, adjusting the velocity value of the grid in the transition region using a linear interpolation algorithm includes: calculating the adjusted velocity value of any grid to be adjusted within the transition region using the following formula:

[0013] V cal =V0+(x cal -x0)(V1-V0) / (x1-x0)

[0014] Among them, V cal x is the adjusted velocity value of the mesh to be adjusted. cal V0 and x0 are the index values ​​of the grid to be adjusted along the slice direction perpendicular to the slice in which the grid to be adjusted is located; V0 and x0 are the velocity values ​​of the first grid in the effective region adjacent to the grid to be adjusted, and the index values ​​of the first grid along the slice direction perpendicular to the slice, respectively; V1 and x1 are the velocity values ​​of the second grid in the boundary region adjacent to the grid to be adjusted, and the index values ​​of the second grid along the slice direction perpendicular to the slice, respectively.

[0015] One embodiment of this application provides an apparatus for establishing a near-surface grid velocity model. The apparatus includes: an establishment module for establishing a first near-surface grid velocity model using tomographic inversion technology based on first arrival time data picked up from shot receivers located in a target work area; a determination module for determining the range of the seismic source excitation point of the target work area based on the coordinates of the shot receivers; a division module for dividing the first near-surface grid velocity model into an effective region and a boundary region based on the range of the seismic source excitation point; and an acquisition module for adjusting the velocity values ​​of the grids in the boundary region based on the velocity values ​​of the grids in the effective region to obtain a second near-surface grid velocity model.

[0016] This application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the method described above when running the program.

[0017] This application provides a storage medium for storing a computer-readable program, which, when run, performs the method described above.

[0018] Compared with the prior art, the technical solutions provided in this application have at least the following advantages:

[0019] In the embodiments provided in this application, a first near-surface grid velocity model is established using tomographic inversion technology based on the first arrival time data collected from shot receivers located in the target work area. The range of the seismic source excitation point in the target work area is determined based on the coordinates of the shot receivers. The first near-surface grid velocity model is divided into an effective region and a boundary region based on the range of the seismic source excitation point. The velocity values ​​of the grids within the effective region are adjusted to the velocity values ​​of the grids within the boundary region to obtain a second near-surface grid velocity model. This allows for the establishment of a high-precision near-surface grid velocity model. Attached Figure Description

[0020] This application will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0021] Figure 1 This is an exemplary flowchart of a method for establishing a near-surface grid velocity model according to some embodiments of this application;

[0022] Figure 2 This is an exemplary schematic diagram illustrating the interactive determination of the effective area and boundary area in a near-surface grid velocity model on a shot-receiver point plan view, according to some embodiments of this application.

[0023] Figure 3This is an exemplary schematic diagram of the effective region and boundary region of a first near-surface grid velocity model according to some embodiments of this application;

[0024] Figure 4 This is an exemplary schematic diagram illustrating a preset search range according to some embodiments of this application;

[0025] Figure 5 This is an exemplary schematic diagram showing, according to some embodiments of this application, the velocity value of the grid to be filled is obtained based on the average value of a first reference velocity value;

[0026] Figure 6 This is an exemplary schematic diagram of a transition region shown according to some embodiments of this application;

[0027] Figure 7 These are exemplary schematic diagrams showing the boundary region before and after processing, according to some embodiments of this application;

[0028] Figure 8 This is an exemplary schematic diagram of an apparatus for establishing a near-surface grid velocity model according to some embodiments of this application;

[0029] Figure 9 This is an exemplary structural diagram of an electronic device according to some embodiments of this application. Detailed Implementation

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0031] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other words can achieve the same purpose, they may be replaced by other expressions.

[0032] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0033] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed precisely in sequence. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0034] For ease of understanding, the technical solution of this application is described below with reference to the accompanying drawings and embodiments.

[0035] Figure 1 This is an exemplary flowchart illustrating a method for establishing a near-surface grid velocity model according to some embodiments of this application. Figure 1 As shown, the method for establishing the near-surface grid velocity model includes the following steps:

[0036] Step S110: Using tomographic inversion technology, a first near-surface grid velocity model is established based on the first arrival time data picked up by the shot receivers set in the target work area.

[0037] In the specific implementation process, the first near-surface grid velocity model is a three-dimensional model, including surface grid and stratum grid. The surface grid represents the grid at the surface location; the stratum grid represents the grid below the surface location.

[0038] Since tomographic inversion technology is based on the ray tracing method, the first near-surface grid velocity model established based on this technology has sparse rays at its boundaries, resulting in low inversion accuracy in the boundary region. This application's embodiments further optimize the boundary region of the first near-surface grid velocity model through the following steps to obtain a more accurate second near-surface grid velocity model, providing a reliable model foundation for amplitude-preserving processing, high-precision imaging, detailed interpretation, and parameter inversion of seismic data.

[0039] Step S120: Determine the range of the seismic source excitation point in the target work area based on the coordinates of the shot receiver.

[0040] In the specific implementation process, an interactive method can be used, such as... Figure 2 The range of the firing point is determined in the plan view of the shot-receiver point shown.

[0041] Step S130: Based on the range of the earthquake source excitation point, the first near-surface grid velocity model is divided into an effective region and a boundary region.

[0042] In practical implementation, the effective region and boundary region in the first near-surface grid velocity model can be determined based on the range of the excitation point. As an example, the region in the first near-surface grid velocity model corresponding to the range of the excitation point can be considered the effective region, and the remaining regions can be considered the boundary regions. For example... Figure 3The effective region and boundary region of the first near-surface grid velocity model shown can be expressed by the following formula:

[0043] V all =V in ∪V out (1)

[0044] Among them, V all V represents the velocity model of the first near-surface grid. in V represents the effective region in the first near-surface grid velocity model. out This represents the boundary region in the first near-surface grid velocity model.

[0045] Since the grid in the effective region of the first near-surface grid velocity model has high accuracy, while the grid in the boundary region has low accuracy and contains grids with empty velocity values, the velocity values ​​of the grids in the effective region can be used to adjust the velocity values ​​of the grids in the boundary region to meet the requirements of a high-precision near-surface grid velocity model.

[0046] Step S140: Based on the velocity values ​​of the grids within the effective area, adjust the velocity values ​​of the grids within the boundary area to obtain the second near-surface grid velocity model.

[0047] Within the boundary region, there are unfilled grids with empty velocity values. For each unfilled grid, the following operation can be performed to calculate its velocity value.

[0048] Determine the preset search range from the grid to be filled (e.g.) Figure 4 The velocity value of the grid within the effective area (shown as a dashed box) where the difference between the elevation value and the elevation value of the grid to be filled is lower than a preset threshold is obtained as the first reference velocity value.

[0049] The velocity values ​​of grids within the effective area where the difference between the elevation value and the elevation value of the grid to be filled is less than a preset threshold include the velocity values ​​of grids with the same elevation value as the grid to be filled, and the velocity values ​​of grids with similar elevation values ​​to the grid to be filled.

[0050] In the specific implementation process, the velocity value of the grid whose elevation value is the same as the elevation value of the grid to be filled can be searched first as the first reference velocity value; if there are few grids searched, the velocity value of the grid whose elevation value is similar to the elevation value of the grid to be filled can be searched as the first reference velocity value.

[0051] If the number of first reference velocity values ​​is greater than 0, the velocity value of the mesh to be filled can be obtained based on the first reference velocity value.

[0052] like Figure 5As shown, the velocity value of the mesh to be filled can be obtained based on the average value of the first reference velocity value. The calculation formula is as follows:

[0053]

[0054] Among them, V zt V represents the velocity value of the z-th mesh to be filled along the depth direction. zi Let be the i-th first reference velocity value with index z along the depth direction found from the effective region, and n be the number of first reference velocity values ​​found.

[0055] When the number of first reference velocity values ​​is 0, the velocity values ​​of the grids within the effective area that are within a preset search range of the grid to be filled and whose depth direction index is the same as that of the grid to be filled can be determined, thus obtaining the second reference velocity value; using the inverse distance weighted interpolation algorithm, the velocity value of the grid to be filled is obtained based on the second reference velocity value.

[0056] In some embodiments, if the elevation value of the grid to be filled is higher than the elevation values ​​of all grids within a preset search range, the maximum and minimum values ​​of the velocity of the grid to be filled can be calculated using an inverse distance weighted interpolation algorithm, and linear filling can be performed.

[0057] In some embodiments, if the elevation value of the grid to be filled is lower than the elevation values ​​of all grids within a preset search range, the velocity value of the grid to be filled can be calculated using an inverse distance weighted interpolation algorithm.

[0058] The formula for the inverse distance weighted interpolation algorithm is shown below:

[0059]

[0060] Among them, V zt V represents the velocity value of the z-th mesh to be filled along the depth direction. zi This refers to the i-th second reference velocity value with index z along the depth direction, found from the effective region. is the distance between the z-th grid to be filled and the grid containing the ith second reference velocity value, and k is the number of second reference velocity values ​​found.

[0061] In some embodiments, the velocity values ​​of the grid within the boundary region can also be smoothed by mean averaging based on a preset smoothing radius. The calculation formula is shown below:

[0062]

[0063] Among them, V new V represents the velocity value of any grid within the smoothed boundary region. iis the velocity value of the i-th grid within the smoothing radius, and n is the number of grids within the smoothing radius.

[0064] In some embodiments, the boundary region can be sliced ​​along the periphery of the effective region to obtain a transition region; the velocity value of the grid in the transition region can be adjusted using a linear interpolation algorithm.

[0065] like Figure 6 As shown, slicing operations can be performed along the x-axis and y-axis directions outside the effective region to obtain the transition region.

[0066] In practical implementation, the adjusted velocity value of any grid to be adjusted within the transition region can be calculated using the following formula:

[0067] V cal =V0+(x cal -x0)(V1-V0) / (x1-x0) (5)

[0068] Among them, V cal x represents the adjusted velocity value of the mesh to be adjusted. cal V0 and x0 are the index values ​​of the grid to be adjusted along the slice direction perpendicular to the slice containing the grid to be adjusted, respectively; V0 and x0 are the velocity values ​​of the first grid in the effective region adjacent to the grid to be adjusted, and the index values ​​of the first grid along the slice direction perpendicular to the slice, respectively; V1 and x1 are the velocity values ​​of the second grid in the boundary region adjacent to the grid to be adjusted, and the index values ​​of the second grid along the slice direction perpendicular to the slice, respectively.

[0069] like Figure 6 The grid to be adjusted shown has its slice orientation along the x-axis; therefore, x cal x0 is the index of the grid to be adjusted along the y-axis; x1 is the index of the first grid along the y-axis; x2 is the index of the second grid along the y-axis.

[0070] In the embodiments provided in this application, tomographic inversion technology is used to establish a first near-surface grid velocity model based on the first arrival time data collected by shot receivers located in the target work area; the range of the source excitation point in the target work area is determined based on the coordinates of the shot receivers; the first near-surface grid velocity model is divided into an effective region and a boundary region based on the range of the source excitation point; and the less accurate parts of the boundary region are adjusted based on the velocity values ​​of the grids within the effective region, such as... Figure 7 As shown, this makes the velocity variation pattern in the boundary area basically consistent with the velocity variation trend in the effective area, providing a more accurate second near-surface grid velocity model for migration imaging.

[0071] The following example, using 3D exploration data from a loess plateau region in western China, illustrates the process of establishing the high-precision near-surface grid velocity model provided in this application:

[0072] (1) Obtain the coordinates and elevation data of the shot and receiver points in the work area, establish the first near-surface grid velocity model using tomographic inversion technology, and determine the parameters of each grid in the model. The grid parameters include the origin coordinates, grid size, elevation value, and index along the x-axis and y-axis. As an example only, the grid size can be: 40 meters in the x-direction, 40 meters in the y-direction, and 10 meters in the z-direction. In the first near-surface grid velocity model, the number of grids in the x, y, and z directions are 968, 732, and 143, respectively.

[0073] (2) Based on the coordinates of the shot receiver, the range of the firing point is defined interactively, such as... Figure 2 As shown.

[0074] Based on the coordinates of the excitation point range, the first near-surface grid velocity model is divided into an effective region and a boundary region.

[0075] (3) For each grid to be filled with a velocity value that is empty in the boundary region, search within the preset search range for a grid with a velocity value that is the same as or similar to the elevation value of the grid to be filled.

[0076] (4) Based on the search results in step (4), use formula (2) and formula (3) to calculate the velocity value of the grid to be filled, ensuring that there are no grids with empty velocity values ​​in the first near-surface grid velocity model.

[0077] (5) Use formula (4) to smooth the velocity values ​​of the grid in the boundary region of the first near-surface grid velocity model to optimize the continuity of the model.

[0078] (6) At the junction of the effective area and the boundary area, a transition area is divided. Using formula (5), the velocity value of each grid in the transition area is optimized to finally obtain a high-precision second near-surface grid velocity model.

[0079] Figure 8 This is an exemplary schematic diagram of an apparatus for establishing a near-surface grid velocity model according to some embodiments of this application.

[0080] like Figure 8 As shown, the device for establishing the near-surface grid velocity model includes: a modeling module 810, a determination module 820, a division module 830, and an adjustment module 840.

[0081] Module 810 is established to use tomographic inversion technology to build a first near-surface grid velocity model based on the first arrival time data picked up by the shot receivers set in the target work area.

[0082] The determination module 820 is used to determine the range of the seismic source excitation point of the target work area based on the coordinates of the shot receiver.

[0083] The partitioning module 830 is used to divide the first near-surface grid velocity model into an effective region and a boundary region based on the range of the seismic source excitation point.

[0084] The adjustment module 840 is used to adjust the velocity values ​​of the grids in the boundary area based on the velocity values ​​of the grids in the effective area, so as to obtain a second near-surface grid velocity model.

[0085] In the embodiments of the above-mentioned near-surface grid velocity model establishment device, the specific processing of each module and the resulting technical effects can be referred to the relevant descriptions in the corresponding method embodiments, and will not be repeated here.

[0086] Figure 9 This is an exemplary structural diagram of an electronic device according to some embodiments of this application.

[0087] like Figure 9 As shown, the electronic device includes: at least one processor 901, at least one communication interface 902, at least one memory 903, and at least one communication bus 904. Optionally, the communication interface 902 can be an interface for a communication module, such as the interface for a GSM module. The processor 901 may be a CPU, an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The memory 903 may include high-speed RAM and may also include non-volatile memory, such as at least one disk storage device. The memory 903 stores a program, and the processor 901 calls the program stored in the memory 903 to execute some or all of the above-described method embodiments.

[0088] This application relates to a storage medium for storing a computer-readable program, which, when run, performs some or all of the above-described method embodiments.

[0089] Optionally, the storage medium may be a non-transitory computer-readable storage medium, such as a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device.

[0090] Based on the same inventive concept, this application also provides a computer program product, including a computer program that, when executed by a processor, implements some or all of the above-described method embodiments.

[0091] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0092] Furthermore, this application uses specific terms to describe its embodiments. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this application do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0093] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this application are not intended to limit the order of the processes and methods of this application. Although the foregoing disclosure has discussed some currently considered useful embodiments of the invention through various examples, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments; rather, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments of this application. For example, while the system components described above can be implemented using hardware devices, they can also be implemented solely through software solutions, such as installing the described system on existing servers or mobile devices.

[0094] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0095] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0096] For each patent, patent application, patent application publication, and other material such as articles, books, specifications, publications, and documents referenced in this application, the entire contents of that patent are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this application, as well as documents that limit the broadest scope of the claims in this application (currently or subsequently appended to this application). It should be noted that if there are any inconsistencies or conflicts between the descriptions, definitions, and / or terminology used in the supplementary materials of this application and the content of this application, the descriptions, definitions, and / or terminology used in this application shall prevail.

[0097] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other modifications may also fall within the scope of this application. Therefore, alternative configurations of the embodiments of this application are considered as examples and not limitations, and are regarded as consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly described and illustrated in this application.

Claims

1. A method for building a near-surface grid velocity model, characterized in that, The method comprises: A first near-surface grid velocity model is established by using tomographic inversion technology according to first arrival time data picked up by shot points arranged in a target work area; A source excitation point range of the target work area is determined according to coordinates of the shot points; The first near-surface grid velocity model is divided into an effective area and a boundary area according to the source excitation point range; Velocity values of grids in the boundary area are adjusted according to velocity values of grids in the effective area, to obtain a second near-surface grid velocity model; There are empty grids to be filled in the boundary area; The adjusting of the velocity values of the grids in the boundary area according to the velocity values of the grids in the effective area comprises: For each grid to be filled, the following operations are performed: Velocity values of grids in the effective area that are within a preset search range of the grid to be filled and have a difference between elevation values and an elevation value of the grid to be filled that is lower than a preset threshold are determined, to obtain first reference velocity values; In response to a number of the first reference velocity values being greater than 0, velocity values of the grid to be filled are obtained according to the first reference velocity values; In response to the number of the first reference velocity values being 0, velocity values of grids in the effective area that are within the preset search range of the grid to be filled and have a same depth direction index as a depth direction index of the grid to be filled are determined, to obtain second reference velocity values; Velocity values of the grid to be filled are obtained according to the second reference velocity values by using an inverse distance weighted interpolation algorithm; The boundary area is sliced along a periphery of the effective area, to obtain a transition area; For any grid to be adjusted in the transition area, an adjusted velocity value of the grid to be adjusted is calculated by using the following formula: wherein, is a speed value of the first grid adjacent to the to-be-adjusted grid in the effective region, is an index value of the first grid adjacent to the to-be-adjusted grid in the effective region along a slice direction perpendicular to a slice where the to-be-adjusted grid is located; V 0, x 0 respectively are a speed value of a first grid in the effective region adjacent to the to-be-adjusted grid, and an index value of the first grid along a direction perpendicular to the slice direction; V 1, x 1 respectively are a speed value of a second grid in the boundary region adjacent to the to-be-adjusted grid, and an index value of the second grid along a direction perpendicular to the slice direction.

2. The method of claim 1, wherein, The obtaining of the velocity values of the grid to be filled according to the first reference velocity values comprises: The velocity values of the grid to be filled are obtained according to an average value of the first reference velocity values.

3. The method of claim 1, wherein, The method further comprises: Velocity values of grids in the boundary area are subjected to mean value smoothing processing according to a preset smoothing radius.

4. An apparatus for building a near-surface grid velocity model, characterized by The device comprises: An establishing module is configured to establish a first near-surface grid velocity model by using tomographic inversion technology according to first arrival time data picked up by shot points arranged in a target work area; A determining module is configured to determine a source excitation point range of the target work area according to coordinates of the shot points; A dividing module is configured to divide the first near-surface grid velocity model into an effective area and a boundary area according to the source excitation point range; An adjusting module is configured to adjust velocity values of grids in the boundary area according to velocity values of grids in the effective area, to obtain a second near-surface grid velocity model; There are empty grids to be filled in the boundary area; The adjusting module is specifically configured to: For each grid to be filled, the following operations are performed: Velocity values of grids in the effective area that are within a preset search range of the grid to be filled and have a difference between elevation values and an elevation value of the grid to be filled that is lower than a preset threshold are determined, to obtain first reference velocity values; in response to the number of the first reference velocity values being greater than 0, obtaining the velocity value of the grid to be filled according to the first reference velocity values; in response to the number of the first reference velocity values being 0, determining the velocity value of a grid in an effective region within a preset search range from the grid to be filled and having the same depth direction index as the grid to be filled, to obtain a second reference velocity value; obtaining the velocity value of the grid to be filled according to the second reference velocity value by using an inverse distance weighted interpolation algorithm; slicing the boundary region along the periphery of the effective region to obtain a transition region; for any grid to be adjusted in the transition region, calculating the adjusted velocity value of the grid to be adjusted by using the following formula: wherein, is a speed value of the first grid adjacent to the to-be-adjusted grid in the effective region, is an index value of the first grid adjacent to the to-be-adjusted grid in the effective region along a slice direction perpendicular to a slice where the to-be-adjusted grid is located; V 0, x 0 respectively are a speed value of a first grid in the effective region adjacent to the to-be-adjusted grid, and an index value of the first grid along a direction perpendicular to the slice direction; V 1, x 1 respectively are a speed value of a second grid in the boundary region adjacent to the to-be-adjusted grid, and an index value of the second grid along a direction perpendicular to the slice direction. 5.An electronic device, comprising a memory and a processor, the memory storing a computer program, and the processor executing the program to perform the method of any one of claims 1 to 3. 6.A storage medium for storing a computer readable program, the computer readable program being executed to perform the method of any one of claims 1 to 3.

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