Depth domain velocity modeling method and device, electronic equipment and storage medium

Abstract

The embodiment of the invention provides a depth domain velocity modeling method and device, electronic equipment and a storage medium, and the method comprises the steps: carrying out the standardized time domain processing of seismic data of a target region, and preliminarily determining the distribution range of a local low-speed geologic body; performing chromatography velocity modeling on a stratum above a local low-speed geologic body in the initial depth domain velocity model of the target area to obtain a first updated depth domain velocity model; determining the spatial position of the local low-speed geologic body according to the first updated depth domain speed model; calculating a new speed corresponding to the spatial position of the local low-speed geologic body; updating the initial speed corresponding to the spatial position of the local low-speed geologic body by adopting the new speed corresponding to the spatial position of the local low-speed geologic body to obtain a second updated depth domain speed model; and performing chromatography velocity modeling on the stratum under the local low-speed geologic body in the second updated depth domain velocity model to obtain a final depth domain velocity model.

Description

Technical Field

[0001] The present application relates to the field of geological exploration technology, and in particular to a depth domain velocity modeling method, device, electronic equipment and storage medium. Background Art

[0002] In oil and gas seismic exploration, karst, caves, goaf or other local low-velocity geological bodies are often encountered. For seismic exploration time migration imaging, the horizontal layered medium assumption is usually adopted. Therefore, using a smooth velocity model, these low-velocity bodies cannot be imaged in the end. At the same time, the imaging of the lower strata of the local low-velocity geological body will also be seriously affected, resulting in many geological illusions.

[0003] The size of these local low-velocity geological bodies is usually tens to hundreds of meters, and their longitudinal wave propagation speed is significantly lower than that of the surrounding rock. In addition, these local low-velocity geological bodies are usually buried deep in space, and their size and shape are irregular, so they are also a difficulty in seismic depth migration imaging.

[0004] The commonly used depth domain velocity modeling method is grid tomography, which adjusts the velocity model by flattening the common imaging point gathers output by the ray method depth migration. However, near these local low-velocity geological bodies, due to their irregular reflections, clear seismic reflection event axes are usually not generated, so accurate common imaging point seismic event axes cannot be picked up. In addition, the assumption of conventional seismic migration grid tomography is that the initial depth domain velocity model is smooth, which is also inconsistent with the actual situation of local low-velocity geological bodies. Summary of the invention

[0005] In view of this, the present application provides a depth domain velocity modeling method, device, electronic device and storage medium, so as to solve the problem of inaccurate depth domain velocity model of local low-velocity geological bodies in the prior art.

[0006] In a first aspect, an embodiment of the present application provides a method for depth domain velocity modeling of a local low-velocity geological body, comprising:

[0007] Perform standardized time domain processing on the seismic data in the target area to preliminarily determine the distribution range of local low-velocity geological bodies;

[0008] Performing tomographic velocity modeling on the strata above the local low-velocity geological body in the initial depth-domain velocity model of the target area to obtain a first updated depth-domain velocity model;

[0009] Determining the spatial position of the local low-velocity geological body according to the first updated depth-domain velocity model;

[0010] Calculating a new velocity corresponding to the spatial position of the local low-velocity geological body;

[0011] Using the new velocity corresponding to the spatial position of the local low-velocity geological body, the initial velocity corresponding to the spatial position of the local low-velocity geological body is updated to obtain a second updated depth-domain velocity model;

[0012] The strata below the local low-velocity geological body in the second updated depth-domain velocity model are subjected to tomographic velocity modeling to obtain a final depth-domain velocity model.

[0013] In some possible implementations, the process of performing standardized time domain processing on the seismic data of the target area to preliminarily determine the distribution range of the local low-velocity geological body includes:

[0014] Perform standardized time domain processing on the seismic data of the target area to obtain a time domain seismic migration stacking section;

[0015] On the time-domain seismic migration stacking section, the distribution range of the local low-velocity geological body is preliminarily determined.

[0016] In some possible implementations, before performing tomographic velocity modeling on the strata above the local low-velocity geological body in the initial depth-domain velocity model of the target area to obtain a first updated depth-domain velocity model, the method further includes:

[0017] The time-domain time migration velocity volume of the target area is converted into the depth domain to obtain an initial depth-domain velocity model of the target area.

[0018] In some possible implementations, determining the spatial position of the local low-velocity geological body according to the first updated depth-domain velocity model includes:

[0019] Performing pre-stack depth volume migration on the first updated depth domain velocity model, wherein the lateral range of the pre-stack depth volume migration completely includes the local low-velocity geological body;

[0020] Pre-processing the common imaging point gathers output by the pre-stack depth volume migration to output a stacked section;

[0021] The 3D coherent attributes are calculated based on the stacked sections to determine the starting depth and lateral distribution range of the local low-velocity geological body.

[0022] In some possible implementations, the fine preprocessing includes filtering, cutting off and / or removing multiple waves.

[0023] In some possible implementations, the calculating a new velocity corresponding to the spatial position of the local low-velocity geological body includes:

[0024] A seismic event is searched below the local low-velocity geological body, and the depth domain d of the seismic event is obtained. 0 ;

[0025] Estimate the correct depth d of the seismic event axis based on the far-offset stacked profile m ;

[0026] According to the depth domain d of the seismic phase axis 0 and the correct depth d m , calculate the depth error Δd of the seismic event axis, where Δd=d 0 -d m ;

[0027] According to the depth error Δd, the longitudinal scale h of the local low-velocity geological body and the initial velocity V corresponding to the spatial position of the local low-velocity geological body 0 , calculate the new velocity V corresponding to the spatial position of the local low-speed geological body new .

[0028] In some possible implementations, the new velocity V corresponding to the spatial position of the local low-velocity geological body is new The calculation formula is: V new =V 0 ×(1-Δd / h).

[0029] In a second aspect, an embodiment of the present application provides a depth domain velocity modeling device for a local low-velocity geological body, comprising:

[0030] The time domain processing module is used to perform standardized time domain processing on the seismic data of the target area and preliminarily determine the distribution range of the local low-velocity geological body;

[0031] An upper stratum tomographic velocity modeling module is used to perform tomographic velocity modeling on the stratum above the local low-velocity geological body in the initial depth-domain velocity model of the target area to obtain a first updated depth-domain velocity model;

[0032] A local low-velocity geological body spatial position determination module, used to determine the spatial position of the local low-velocity geological body according to the first updated depth domain velocity model;

[0033] A new velocity calculation module, used for calculating a new velocity corresponding to the spatial position of the local low-velocity geological body;

[0034] A velocity updating module, for updating the initial velocity corresponding to the spatial position of the local low-velocity geological body by adopting the new velocity corresponding to the spatial position of the local low-velocity geological body, to obtain a second updated depth domain velocity model;

[0035] The lower stratum tomographic velocity modeling module is used to perform tomographic velocity modeling on the stratum below the local low-velocity geological body in the second updated depth-domain velocity model to obtain a final depth-domain velocity model.

[0036] In a third aspect, an embodiment of the present application provides an electronic device, including:

[0037] processor;

[0038] Memory;

[0039] And a computer program, wherein the computer program is stored in the memory, and the computer program includes instructions, and when the instructions are executed by the processor, the electronic device executes any one of the methods described in the first aspect.

[0040] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute any one of the methods described in the first aspect.

[0041] In the embodiment of the present application, an accurate depth domain velocity model of the local low-velocity geological body can be established, and then in the subsequent depth migration imaging, the real stratigraphic structure of the lower part of the local low-velocity geological body can be accurately restored, eliminating various messy reflections and structural illusions such as pull-down of the lower stratigraphic reflection sync axes of the local low-velocity geological body on the depth domain migration imaging section. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0043] Figure 1 A schematic flow chart of a method for depth-domain velocity modeling of a local low-velocity geological body provided in an embodiment of the present application;

[0044] Figure 2 A schematic diagram of longitudinal scale picking of a local low-velocity geological body provided in an embodiment of the present application;

[0045] Figure 3 A schematic diagram of a depth domain velocity model provided in an embodiment of the present application;

[0046] Figure 4 A schematic diagram of a prestack depth migration imaging result provided in an embodiment of the present application;

[0047] Figure 5 This is a structural block diagram of a depth domain velocity modeling device for a local low-velocity geological body provided in this application;

[0048] Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0050] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0051] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0052] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0053] In view of the problems existing in the prior art, the embodiment of the present application provides a method for modeling the depth domain velocity of a local low-velocity geological body, which can establish an accurate depth domain velocity model of the local low-velocity geological body, and then accurately restore the real stratigraphic structure of the lower part of the local low-velocity geological body in the subsequent depth migration imaging, and eliminate various chaotic reflections and structural illusions such as pull-down of the lower stratigraphic reflection event axis of the local low-velocity geological body on the depth domain migration imaging section. The following is a detailed description in conjunction with the accompanying drawings.

[0054] See also Figure 1 , is a flow chart of a method for depth-domain velocity modeling of a local low-velocity geological body provided in an embodiment of the present application. Figure 1 As shown, it mainly includes the following steps.

[0055] Step S101: Perform standardized time domain processing on the seismic data of the target area to preliminarily determine the distribution range of the local low-velocity geological body.

[0056] In the specific implementation, before fine-grained depth-domain velocity modeling of local low-velocity geological bodies is performed, conventional standardized time-domain processing of seismic data collected during field construction is first required. The main purpose is to calculate the root mean square velocity of the underground strata, and at the same time, the seismic migration stacking section in the time domain can be obtained. On the time-domain seismic migration section, the distribution range of the local low-velocity geological body can be roughly determined.

[0057] Therefore, the above step S101 specifically includes: performing standardized time domain processing on the seismic data of the target area to obtain a time domain seismic migration stacking section; and preliminarily determining the distribution range of the local low-velocity geological body on the time domain seismic migration stacking section.

[0058] Step S102: performing tomographic velocity modeling on the strata above the local low-velocity geological body in the initial depth-domain velocity model of the target area to obtain a first updated depth-domain velocity model.

[0059] Usually, local low-velocity geological bodies are developed in strata of a certain geological age, so the depth domain velocity modeling of local low-velocity geological bodies can be realized by vertical division. First, conventional tomographic velocity modeling is performed on the strata above the local low-velocity geological body to ensure that the distortion and error of the lower strata are caused by the velocity error of the local low-velocity geological body.

[0060] In a specific implementation, before modeling a local low-velocity geological body, an initial depth domain velocity model is first required, which can be obtained by converting the time-domain time-migrated velocity body to the depth domain. In other words, the time-domain time-migrated velocity body of the target area can be converted to the depth domain to obtain the initial depth domain velocity model of the target area.

[0061] After obtaining the initial depth domain velocity model of the target area, conventional tomographic velocity modeling can be performed on the strata above the local low-velocity geological body in the initial depth domain velocity model of the target area to obtain an optimized depth domain velocity model. For the sake of distinction, the depth domain velocity model is referred to as the first updated depth domain velocity model. The conventional tomographic velocity modeling method can be found in the description of the prior art, and for the sake of brevity, it will not be repeated here.

[0062] Step S103: Determine the spatial position of the local low-velocity geological body according to the first updated depth-domain velocity model.

[0063] Specifically, after obtaining the first updated depth domain velocity model, the first updated depth domain velocity model can be used to perform a small-scale pre-stack depth body migration, requiring the lateral range to completely contain the local low-velocity geological body. The common imaging point gather output by the pre-stack depth body migration is finely preprocessed, including filtering, cutting and removing multiple waves, etc. Then the stacked section is stacked and output as the basis for determining the spatial position of the local low-velocity geological body in the depth domain. Since the local low-velocity geological body should be closely related to the starting point of the noise area, the corresponding starting depth and lateral distribution range of the local low-velocity geological body can be determined by calculating the 3D coherence attribute, that is, the spatial position of the local low-velocity geological body is determined.

[0064] Since the initial velocity V of the local low-speed geological body is required in the subsequent steps 0 Therefore, after determining the spatial position of the local low-velocity geological body, the initial velocity V corresponding to the spatial position of the local low-velocity geological body can be obtained in the first updated depth domain velocity model. 0 (In other parts of this article, it may also be simply referred to as the initial velocity V of the local low-velocity geological body. 0 ).

[0065] Step S104: Calculate the new velocity corresponding to the spatial position of the local low-velocity geological body.

[0066] Since the size of the local low-velocity geological body is usually tens to hundreds of meters, the shape is irregular, and the reflection of its lower part is usually chaotic, it is usually impossible to pick up its accurate lower boundary. Through research, it is found that the influence of the local low-velocity geological body on the seismic reflection wave is a comprehensive effect. Therefore, the reflection seismic phase axis of the continuous stratum affected below the geological body can be found, and the depth error of the seismic reflection phase axis of the stratum can be used to infer the velocity of the local low-velocity geological body. Specifically, it includes the following steps.

[0067] First, find a relatively continuous seismic phase axis below the local low-velocity geological body and pick up the corresponding depth domain d 0 , because the velocity of the local low-velocity geological body is low, the phase axis at its lower part will have an obvious downward pull phenomenon, such as Figure 2 As shown. Using the far-biased stacked profile, the correct depth d of the lower stratum can be inferred m , and use Formula 1 to calculate the corresponding depth error.

[0068] Formula 1:

[0069] Δd=d 0 -d m

[0070] Secondly, by transmitting the depth error upward, the Δd obtained by picking up the calculation is used as the calculation basis of the local low-speed geological body. After mathematical derivation and theoretical simplification, the new velocity of the local low-speed geological body is calculated using Formula 2.

[0071] Formula 2:

[0072] V new =V 0 ×(1-Δd / h)

[0073] Among them, V new is the new velocity of the local low-velocity geological body, and h is the estimated longitudinal scale of the local low-velocity geological body.

[0074] Step S105: using the new velocity corresponding to the spatial position of the local low-velocity geological body, the initial velocity corresponding to the spatial position of the local low-velocity geological body is updated to obtain a second updated depth-domain velocity model.

[0075] Specifically, after obtaining the new velocity V of the local low-velocity geological body new After that, the new speed V new The original initial velocity is edited as the velocity of the local low-velocity geological body, thereby obtaining an optimized depth-domain velocity model. For the sake of distinction, the depth-domain velocity model is referred to as the second updated depth-domain velocity model.

[0076] In addition, after obtaining the second updated depth domain velocity model, the second updated depth domain velocity model can also be used as the first updated depth domain velocity model, returning to step S103, and re-performing steps S103-S105. Then, the second updated depth domain velocity models obtained twice are compared, and the second updated depth domain velocity model is quality-controlled based on the comparison result to determine whether it is reasonable. If the second updated depth domain velocity model still has room for improvement, steps S103-S105 can be re-performed.

[0077] Step S106: performing tomographic velocity modeling on the strata below the local low-velocity geological body in the second updated depth-domain velocity model to obtain a final depth-domain velocity model.

[0078] Specifically, after obtaining the second updated depth domain velocity model, conventional tomographic velocity modeling can be performed on the strata below the local low-velocity geological body in the second updated depth domain velocity model to obtain the final depth domain velocity model. The conventional tomographic velocity modeling method can be referred to the description in the prior art, and will not be described here for the sake of brevity.

[0079] Furthermore, after obtaining the final depth-domain velocity model, wave equation reverse time migration can be used to obtain better local low-velocity geological body imaging results.

[0080] By adopting the technical solution provided in the embodiment of the present application, an accurate depth domain velocity model of the local low-velocity geological body can be established, and then in the subsequent depth migration imaging, the real stratigraphic structure of the lower part of the local low-velocity geological body can be accurately restored, eliminating various messy reflections and structural illusions such as pull-down of the lower stratigraphic reflection sync axis of the local low-velocity geological body on the depth domain migration imaging section.

[0081] For ease of understanding, the technical solution provided in the embodiment of the present application is described in detail below in conjunction with a specific application scenario.

[0082] During the time domain processing of the seismic data collected in the area, the applicant found that the seismic event axes at certain locations were pulled down, the signal-to-noise ratio of the time domain seismic signal in the lower strata was reduced, the event axes were also distorted, and vertical false faults appeared in the most serious places. Geologists initially believed that the event axis was misaligned due to a large stratum fault, but no large-scale faults were found to extend horizontally on the stratum coherent slices, so they believed that it was caused by the local development of low-speed geological bodies. In order to eliminate the event axis misalignment caused by the velocity error of the low-speed geological body, this method was used to perform fine velocity modeling of the local low-speed geological body in the depth domain.

[0083] See also Figure 3 , is a schematic diagram of a depth domain velocity model provided in an embodiment of the present application. Among them, Figure 3 The left figure in the figure is the depth domain velocity model before adding the local low-velocity geological body; Figure 3 The figure on the right is the depth domain velocity model after adding the local low-velocity geological body.

[0084] See also Figure 4 , is a schematic diagram of a prestack depth migration imaging result provided in an embodiment of the present application. Among them, Figure 4 The left side figure is the prestack depth migration imaging result without using the method provided in the embodiment of the present application for accurate velocity modeling. Figure 4 As can be seen in the left figure, since the initial velocity model of the low-speed geological body did not take the internal low velocity into consideration, a series of strata below were affected. The impact became greater as one went downwards, from local pull-down to faulting and chaotic reflection. Figure 4 The figure on the right side of the figure is the pre-stack depth migration imaging result of accurate velocity modeling using the method provided in the embodiment of the present application. Figure 4 As can be seen in the right figure, the imaging of the lower strata has been significantly improved, restoring the true layered reflection structure, eliminating the previous reflection illusion, and avoiding potential drilling risks. In addition, it was confirmed in the subsequent drilling process that there was indeed no development of faults.

[0085] Corresponding to the above-mentioned embodiments, the present application also provides a depth domain velocity modeling device for a local low-velocity geological body.

[0086] See also Figure 5 , is a structural block diagram of a depth domain velocity modeling device for a local low-velocity geological body provided in this application. Figure 5 As shown, it mainly includes the following modules.

[0087] The time domain processing module 501 is used to perform standardized time domain processing on the seismic data of the target area and preliminarily determine the distribution range of the local low-velocity geological body;

[0088] An upper stratum tomographic velocity modeling module 502 is used to perform tomographic velocity modeling on the stratum above the local low-velocity geological body in the initial depth-domain velocity model of the target area to obtain a first updated depth-domain velocity model;

[0089] A local low-velocity geological body spatial position determination module 503 is used to determine the spatial position of the local low-velocity geological body according to the first updated depth domain velocity model;

[0090] A new velocity calculation module 504 is used to calculate a new velocity corresponding to the spatial position of the local low-velocity geological body;

[0091] The velocity updating module 505 is used to update the initial velocity corresponding to the spatial position of the local low-velocity geological body by using the new velocity corresponding to the spatial position of the local low-velocity geological body to obtain a second updated depth domain velocity model;

[0092] The lower stratum tomographic velocity modeling module 506 is used to perform tomographic velocity modeling on the stratum below the local low-velocity geological body in the second updated depth-domain velocity model to obtain a final depth-domain velocity model.

[0093] It should be pointed out that the specific contents involved in the embodiments of the present application can be found in the description of the above method embodiments, and for the sake of brevity, they will not be repeated here.

[0094] Corresponding to the above embodiment, an embodiment of the present application further provides an electronic device.

[0095] See also Figure 6 , is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 6 As shown, the electronic device 600 may include: a processor 601, a memory 602 and a communication unit 603. These components communicate via one or more buses. Those skilled in the art will appreciate that the electronic device structure shown in the figure does not limit the embodiments of the present application, and it may be a bus structure or a star structure, and may include more or fewer components than shown in the figure, or combine certain components, or arrange components differently.

[0096] The communication unit 603 is used to establish a communication channel so that the electronic device can communicate with other devices.

[0097] The processor 601 is the control center of the electronic device. It uses various interfaces and lines to connect various parts of the entire electronic device. It runs or executes software programs and / or modules stored in the memory 602, and calls data stored in the memory to perform various functions of the electronic device and / or process data. The processor can be composed of an integrated circuit (IC), for example, it can be composed of a single packaged IC, or it can be composed of multiple packaged ICs with the same or different functions. For example, the processor 601 can include only a central processing unit (CPU). In the embodiment of the present application, the CPU can be a single computing core or multiple computing cores.

[0098] Memory 602 is used to store execution instructions of processor 601. Memory 602 can be implemented by any type of volatile or non-volatile storage device or a combination of them, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0099] When the execution instructions in the memory 602 are executed by the processor 601 , the electronic device 600 is enabled to execute part or all of the steps in the above method embodiment.

[0100] Corresponding to the above embodiment, the embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium may store a program, wherein when the program is running, the device where the computer-readable storage medium is located may be controlled to perform some or all of the steps in the above method embodiment. In a specific implementation, the computer-readable storage medium may be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM).

[0101] Corresponding to the above-mentioned embodiment, the embodiment of the present application further provides a computer program product, which includes executable instructions. When the executable instructions are executed on a computer, the computer executes some or all of the steps in the above-mentioned method embodiment.

[0102] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0103] Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0104] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0105] In several embodiments provided in the present application, any function can be stored in a computer-readable storage medium if it is implemented in the form of a software functional unit and sold or used as an independent product. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., and other media that can store program codes.

[0106] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for depth domain velocity modeling of a local low-velocity geological body, characterized in that: include: Perform standardized time domain processing on the seismic data in the target area to preliminarily determine the distribution range of local low-velocity geological bodies; Performing tomographic velocity modeling on the strata above the local low-velocity geological body in the initial depth-domain velocity model of the target area to obtain a first updated depth-domain velocity model; Determining the spatial position of the local low-velocity geological body according to the first updated depth-domain velocity model; Calculating a new velocity corresponding to the spatial position of the local low-velocity geological body; Using the new velocity corresponding to the spatial position of the local low-velocity geological body, the initial velocity corresponding to the spatial position of the local low-velocity geological body is updated to obtain a second updated depth-domain velocity model; The strata below the local low-velocity geological body in the second updated depth-domain velocity model are subjected to tomographic velocity modeling to obtain a final depth-domain velocity model.

2. The method according to claim 1, characterized in that The standardized time domain processing of the seismic data of the target area is performed to preliminarily determine the distribution range of the local low-velocity geological body, including: Perform standardized time domain processing on the seismic data of the target area to obtain a time domain seismic migration stacking section; On the time-domain seismic migration stacking section, the distribution range of the local low-velocity geological body is preliminarily determined.

3. The method according to claim 1, characterized in that Before performing tomographic velocity modeling on the strata above the local low-velocity geological body in the initial depth-domain velocity model of the target area to obtain a first updated depth-domain velocity model, the method further includes: The time-domain time migration velocity volume of the target area is converted into the depth domain to obtain an initial depth-domain velocity model of the target area.

4. The method according to claim 1, characterized in that Determining the spatial position of the local low-velocity geological body according to the first updated depth-domain velocity model includes: Performing pre-stack depth volume migration on the first updated depth domain velocity model, wherein the lateral range of the pre-stack depth volume migration completely includes the local low-velocity geological body; Pre-processing the common imaging point gathers output by the pre-stack depth volume migration to output a stacked section; The 3D coherent attributes are calculated based on the stacked sections to determine the starting depth and lateral distribution range of the local low-velocity geological body.

5. The method according to claim 4, characterized in that The detailed pre-processing includes filtering, cutting off and / or removing multiple waves.

6. The method according to claim 1, characterized in that The calculating of the new velocity corresponding to the spatial position of the local low-velocity geological body comprises: Finding a seismic event below the local low-velocity geological body and obtaining a depth domain d0 of the seismic event; Estimate the correct depth d of the seismic event axis based on the far-offset stacked profile m ; According to the depth domain d0 of the seismic phase axis and the correct depth d m , calculate the depth error Δd of the seismic event axis, where Δd = d0-d m ; According to the depth error Δd, the longitudinal scale h of the local low-velocity geological body and the initial velocity V0 corresponding to the spatial position of the local low-velocity geological body, a new velocity V corresponding to the spatial position of the local low-velocity geological body is calculated. new .

7. The method according to claim 6, characterized in that The new velocity V corresponding to the spatial position of the local low-speed geological body new The calculation formula is: V new =V0×(1-Δd / h).

8. A depth domain velocity modeling device for a local low-velocity geological body, characterized in that: include: The time domain processing module is used to perform standardized time domain processing on the seismic data of the target area and preliminarily determine the distribution range of the local low-velocity geological body; An upper stratum tomographic velocity modeling module is used to perform tomographic velocity modeling on the stratum above the local low-velocity geological body in the initial depth-domain velocity model of the target area to obtain a first updated depth-domain velocity model; A local low-velocity geological body spatial position determination module, used to determine the spatial position of the local low-velocity geological body according to the first updated depth domain velocity model; A new velocity calculation module, used for calculating a new velocity corresponding to the spatial position of the local low-velocity geological body; A velocity updating module, configured to update an initial velocity corresponding to the spatial position of the local low-velocity geological body by adopting a new velocity corresponding to the spatial position of the local low-velocity geological body, so as to obtain a second updated depth domain velocity model; The lower stratum tomographic velocity modeling module is used to perform tomographic velocity modeling on the stratum below the local low-velocity geological body in the second updated depth-domain velocity model to obtain a final depth-domain velocity model.

9. An electronic device, characterized in that: include: processor; Memory; And a computer program, wherein the computer program is stored in the memory, and the computer program includes instructions, and when the instructions are executed by the processor, the electronic device executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method according to any one of claims 1 to 7.

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