Method, apparatus and machine readable storage medium for channel set correction

Abstract

The application provides a gather correction method and device and a machine readable storage medium, and relates to the technical field of geophysical exploration. The method comprises the following steps: determining a high-frequency static correction amount by matching analysis of a real underground model of a target work area, an initial near-surface velocity model, a smoothing model for pre-stack depth migration and travel time; and correcting CMP gathers of the target work area which have not undergone any static correction processing by using the high-frequency static correction amount. The above method is based on the matching of the model and the travel time, obtains the high-frequency static correction amount for matching the smoothing model and the travel time, and corrects the CMP gathers which have not undergone any static correction by using the high-frequency static correction amount, thereby improving the matching degree of the near-surface model and the travel time of the seismic wave field, and further improving the pre-stack depth migration velocity modeling and imaging quality.

Description

Technical Field

[0001] This application belongs to the field of geophysical exploration technology, specifically relating to a gather correction method, a pre-stack depth migration method, a full-depth-domain velocity modeling method, a gather correction device, a pre-stack depth migration device, a full-depth-domain velocity modeling device, a computer device, and a machine-readable storage medium. Background Technology

[0002] Complex exploration areas are crucial for future oil and gas discovery. The consensus among geophysical researchers is that "the target is deep, the problem is shallow, the core is velocity, the focus is on precision, and the key is innovation." Traditional migration surfaces (migration initiation surfaces) obtained through time-domain processing lack practical physical meaning. The assumptions based on hyperbolic curves and bedding distort the true travel time information of seismic wave fields. Modeling from these surfaces will misrepresent the true subsurface velocity structure, hindering velocity modeling and imaging in complex areas. Depth migration velocity modeling should begin with topographically relevant depth migration surfaces (depth migration initiation surfaces). These surfaces have practical physical meaning. Establishing near-surface velocity models from these surfaces can preserve the true travel time characteristics of seismic wave fields as much as possible, recovering the true subsurface velocity structure. This allows for better utilization of subsurface structures and velocity information obtained from zero-bias VSP and sonic logging, theoretically enabling the handling of more complex problems. Currently, the main focus of debate in academia and industry revolves around: which depth offset surface to use, the extent of smoothing, how to use near-surface velocity models, whether or not to smooth, how to correct gathers, and how to calculate high-frequency static corrections. At present, there are various approaches to these issues, and many of them are even erroneous. However, the most fundamental aspects of the debate are how to correct gathers and how to calculate high-frequency static corrections, requiring the establishment of a scientific theoretical framework, formula derivation, and practical application based on these principles. However, this work has not yet been adequately completed.

[0003] In summary, there is an urgent need to propose a reasonable and feasible gather correction scheme to meet the requirements of depth domain velocity modeling and pre-stack depth migration imaging in dual complex exploration areas. Summary of the Invention

[0004] The purpose of this application is to provide a gather correction method, a pre-stack depth migration method, a full-depth-domain velocity modeling method, a gather correction device, a pre-stack depth migration device, a full-depth-domain velocity modeling device, a computer device, and a machine-readable storage medium to meet the requirements of velocity modeling and imaging in dual-complex exploration areas.

[0005] To achieve the above objectives, a first aspect of this application provides a gather correction method, comprising:

[0006] By matching analysis of the underground real model of the target work area, the obtained initial near-surface velocity model, the smoothed model used for pre-stack depth migration, and the travel time, the difference between the static correction of the initial near-surface velocity model and the static correction of the smoothed model is determined. The sum of the initial arrival residual static correction after static correction using the initial near-surface velocity model and the difference is taken as the high-frequency static correction. The smoothed model is obtained by preprocessing the initial near-surface velocity model. The static correction calculation using the initial near-surface velocity model uses the real terrain surface of the target work area as the depth migration surface, and the static correction calculation using the smoothed model uses the target terrain surface as the depth migration surface. The type of the target terrain surface includes a smoothed real terrain surface and a smoothed terrain surface.

[0007] The high-frequency static correction amount is used to correct the CMP gather in the target work area that has not undergone any static correction treatment.

[0008] In a specific embodiment of this application, the static correction amount of the smoothing model is calculated using the following formula:

[0009] st S =tt SRD -tt model ;

[0010] Among them, st S This represents the static correction amount of the model for shot points or receiver points within the target work area; tt SRD HVI-SRD represents the distance between the high-velocity layer top interface and the fixed reference plane when the shot point or receiver point travels from a preset fixed reference plane to the high-velocity layer top interface. replace Indicates the replacement speed; tt model When representing the travel distance from the target terrain surface to the top interface of the high-velocity layer, dl and dv represent the depth direction mesh size and the wave velocity within the mesh in the smoothed model after meshing, respectively. This represents the integral from the target terrain surface to the top interface of the high-speed layer.

[0011] In a specific embodiment of this application, the initial near-surface velocity model is a near-surface velocity model obtained using a near-surface velocity inversion method.

[0012] In a specific embodiment of this application, the matching analysis of the underground real model, initial near-surface velocity model, smoothing model, and travel time of the target work area includes:

[0013] The travel time tt of the underground real model, the initial near-surface velocity model, and the smoothed model of the target work area from the fixed reference surface to the top interface of the high-velocity layer are determined respectively.T 、Time travel I 、Time travel S ;

[0014] According to the time tt T 、Time travel I 、Time travel S The formula for correcting the trace collection is derived.

[0015] Determine the expression for the high-frequency static correction amount used to correct CMP gathers that have not undergone any static correction processing.

[0016] in, Topo-SRD represents the distance between the actual terrain surface and the fixed reference surface; FD-SRD represents the distance between the target terrain surface and the fixed reference surface; This represents the integral from the real terrain surface to the top interface of the high-velocity layer; st I This represents the static correction value of the initial near-surface velocity model; data s This represents the CMP gather after high-frequency static correction; data T This indicates a CMP gather that has not undergone any static correction. This represents the initial arrival residual static correction amount after static correction using the initial near-surface velocity model; dv T dv I dv S These represent the wave velocities within the meshes of the actual underground model, the initial near-surface velocity model, and the smoothed model, respectively; st high This indicates the high-frequency static correction amount.

[0017] In a specific embodiment of this application, based on the time tt T 、Time travel I 、Time travel S The gather correction formula is derived, including:

[0018] Establish the first equation tt S -tt T =tt S -tt I +tt I -tt T ;

[0019] Add to both sides of the first equation Expanding the terms on the right side of the first equation, we obtain the second equation.

[0020]

[0021] Except for tt, the left side of the second equation S Move all other terms to the right to obtain the third equation.

[0022] Moving the shot receiver position from the fixed reference plane to the depth offset plane yields the fourth equation.

[0023] because Express the fourth equation as the fifth equation.

[0024] Simplifying the fifth equation yields the correction formula for the collection of passages.

[0025] Wherein, HVI-FD represents the distance between the high-velocity top interface and the target terrain surface; HVI-Topo represents the distance between the high-velocity top interface and the real terrain surface.

[0026] In a specific embodiment of this application, the type of the target terrain surface also includes the submersion of the terrain surface.

[0027] In a specific embodiment of this application, the preprocessing includes at least one of smoothing out velocity anomalies and velocity separation below a first lower limit value.

[0028] A second aspect of this application provides a pre-stack depth offset method, comprising:

[0029] A smoothing model of the target work area is constructed, which is obtained by preprocessing the initial near-surface velocity model.

[0030] Using the target terrain surface as the depth offset surface, pre-stack depth offset is performed using the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing based on the gather correction method according to any one of claims 1 to 7. The type of the target terrain surface includes a smooth real terrain surface and a smoothed terrain surface.

[0031] A third aspect of this application provides a full-depth-domain velocity modeling method, comprising:

[0032] A smoothing model of the target work area is constructed, which is obtained by preprocessing the initial near-surface velocity model.

[0033] Full-depth domain velocity construction of the target work area is performed using the corrected CMP gather and the smoothing model.

[0034] The corrected CMP gather is obtained by correcting the CMP gather in the target work area without any static correction treatment using the gather correction method according to any one of claims 1 to 7.

[0035] A fourth aspect of this application provides a road gather correction device, comprising:

[0036] The high-frequency static correction calculation module is used to determine the difference between the static correction of the initial near-surface velocity model and the static correction of the smoothed model by using the underground real model of the target work area, the obtained initial near-surface velocity model, the smoothed model used for pre-stack depth migration, and the travel time matching analysis. The module then uses the sum of the initial arrival residual static correction after static correction using the initial near-surface velocity model and the difference value as the high-frequency static correction. The smoothed model is obtained by preprocessing the initial near-surface velocity model. The static correction calculation using the initial near-surface velocity model uses the real terrain surface of the target work area as the depth migration surface, and the static correction calculation using the smoothed model uses the target terrain surface as the depth migration surface. The target terrain surface can be either a smoothed real terrain surface or a smoothed terrain surface.

[0037] The gather correction module is used to correct the CMP gathers in the target work area that have not undergone any static correction processing using the high-frequency static correction amount.

[0038] In a specific embodiment of this application, the static correction amount of the smoothing model is calculated using the following formula:

[0039] st S =tt SRD -tt model ;

[0040] Among them, st S This represents the static correction amount of the model for shot points or receiver points within the target work area; tt SRD HVI-SRD represents the distance between the high-velocity layer top interface and the fixed reference plane when the shot point or receiver point travels from a preset fixed reference plane to the high-velocity layer top interface. replace Indicates the replacement speed; tt model When representing the travel distance from the target terrain surface to the top interface of the high-velocity layer, dl and dv represent the depth direction mesh size and the wave velocity within the mesh in the smoothed model after meshing, respectively. This represents the integral from the target terrain surface to the top interface of the high-speed layer.

[0041] In a specific embodiment of this application, the initial near-surface velocity model is a near-surface velocity model obtained using a near-surface velocity inversion method.

[0042] In a specific embodiment of this application, the matching analysis of the underground real model, initial near-surface velocity model, smoothing model, and travel time of the target work area includes:

[0043] The travel time tt of the underground real model, the initial near-surface velocity model, and the smoothed model of the target work area from the fixed reference surface to the top interface of the high-velocity layer are determined respectively. T 、Time travel I 、Time travel S ;

[0044] According to the time tt T 、Time travel I 、Time travel S The formula for correcting the trace collection is derived.

[0045] Determine the expression for the high-frequency static correction amount used to correct CMP gathers that have not undergone any static correction processing.

[0046] in, Topo-SRD represents the distance between the actual terrain surface and the fixed reference surface; FD-SRD represents the distance between the target terrain surface and the fixed reference surface; This represents the integral from the real terrain surface to the top interface of the high-velocity layer; st I This represents the static correction value of the initial near-surface velocity model; data s This represents the CMP gather after high-frequency static correction; data T This indicates a CMP gather that has not undergone any static correction. This represents the initial arrival residual static correction amount after static correction using the initial near-surface velocity model; dv T dv I dv S These represent the wave velocities within the meshes of the actual underground model, the initial near-surface velocity model, and the smoothed model, respectively; st high This indicates the high-frequency static correction amount.

[0047] In a specific embodiment of this application, based on the time tt T 、Time travel I 、Time travel S The gather correction formula is derived, including:

[0048] Establish the first equation tt S -tt T =tt S -tt I +ttI -tt T ;

[0049] Add to both sides of the first equation Expanding the terms on the right side of the first equation, we obtain the second equation.

[0050] Except for tt, the left side of the second equation S Move all other terms to the right to obtain the third equation.

[0051] Moving the shot receiver position from the fixed reference plane to the depth offset plane yields the fourth equation.

[0052] because Express the fourth equation as the fifth equation.

[0053] Simplifying the fifth equation yields the correction formula for the collection of passages.

[0054] Wherein, HVI-FD represents the distance between the high-velocity top interface and the target terrain surface; HVI-Topo represents the distance between the high-velocity top interface and the real terrain surface.

[0055] In a specific embodiment of this application, the type of the target terrain surface also includes the submersion of the terrain surface.

[0056] In a specific embodiment of this application, the preprocessing includes at least one of smoothing out speed anomalies and separating speeds below a first lower limit.

[0057] The fifth aspect of this application provides a pre-stack depth offset device, comprising:

[0058] The first construction module is used to construct a smooth model of the target work area. The smooth model is obtained by preprocessing the initial near-surface velocity model.

[0059] The pre-stack depth migration module is used to perform pre-stack depth migration using the target terrain surface as the depth migration surface and the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing by the gather correction method based on the first aspect of this application. The type of the target terrain surface includes a smooth real terrain surface and a smoothed terrain surface.

[0060] The sixth aspect of this application provides a full-depth-domain velocity modeling apparatus, comprising:

[0061] The second construction module is used to construct a smoothing model of the target work area. The smoothing model is obtained by preprocessing the initial near-surface velocity model.

[0062] The velocity modeling module is used to perform full-depth domain velocity modeling of the target work area using the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing using the gather correction method described in the first aspect of this application.

[0063] The seventh aspect of this application provides a computer device, comprising:

[0064] The memory is configured to store instructions; and

[0065] The processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the gather correction method according to the first aspect of this application, the pre-stack depth migration method according to the second aspect of this application, or the full depth domain velocity modeling method according to the third aspect of this application.

[0066] An eighth aspect of this application provides a machine-readable storage medium storing instructions for causing a machine to perform a gather correction method according to a first aspect of this application, a pre-stack depth migration method according to a second aspect of this application, or a full-depth-domain velocity modeling method according to a third aspect of this application.

[0067] After collecting the initial near-surface velocity model, the static correction amount calculated using the initial near-surface velocity model, and the first-arrival residual static correction amount, the above technical solution, based on the technical concept of matching the near-surface velocity model and travel time, determines the difference between the static correction amount calculated using the smoothing model and the static correction amount calculated using the initial near-surface velocity model. Then, after considering the application of the first-arrival residual static correction amount pre-stack, it derives a high-frequency static correction amount for correcting CMP gathers that have not undergone any static correction processing, so as to match the smoothing model used in pre-stack depth migration imaging. This improves the matching degree between the seismic wavefield travel time and the near-surface velocity model when pre-stack depth migration or full-depth domain velocity modeling that can be used for pre-stack depth migration, thereby improving the quality of pre-stack depth migration velocity modeling and imaging.

[0068] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0069] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0070] Figure 1 A flowchart illustrating a gather correction method according to an embodiment of this application is shown schematically.

[0071] Figure 2 A flowchart illustrating a pre-stack depth offset method according to an embodiment of this application is shown schematically;

[0072] Figure 3 A flowchart illustrating a full-depth domain velocity modeling method according to an embodiment of this application is shown schematically.

[0073] Figure 4a This diagram illustrates a real-world model of the Earth's surface and subsurface.

[0074] Figure 4b A schematic diagram of the initial near-surface velocity model is shown.

[0075] Figure 4c A schematic diagram of the smoothing model is shown.

[0076] Figure 5 The flowchart of the pre-stack depth migration method in a specific application example is illustrated schematically;

[0077] Figure 6a The diagram illustrates the initial near-surface velocity model obtained by inversion in a specific application example.

[0078] Figure 6b Schematic illustration of the Figure 6a A schematic diagram of the smoothed model obtained after smoothing the initial near-surface velocity model shown.

[0079] Figure 7 A schematic diagram of a depth offset surface in a specific application example is shown;

[0080] Figure 8 The diagram illustrates a specific application example of the meshed high-speed layer top interface.

[0081] Figure 9a This diagram illustrates the synthesized static correction of the detector point in a specific application example of Model I.

[0082] Figure 9b This diagram illustrates the static correction of the detector point model in a specific application example.

[0083] Figure 9c This diagram illustrates the static correction of the detector point model in a specific application example.

[0084] Figure 10aThis schematically illustrates the two-way travel time from the fixed reference plane SRD to the depth offset plane FD at the S-model replacement velocity in a specific application example.

[0085] Figure 10b This illustration shows a two-way travel time diagram from the depth migration plane FD to the high-velocity top interface HVI in the S-model in a specific application example.

[0086] Figure 10c This illustration shows a two-way travel time diagram from the depth offset plane FD to the high-velocity top interface HVI at a specific application example.

[0087] Figure 11a The diagram illustrates a CMP gather in work area A without any static correction.

[0088] Figure 11b Schematic illustration Figure 11a The diagram shown is a schematic of the CMP gather after applying high-frequency static correction.

[0089] Figure 12 The diagram illustrates the high-frequency static correction amount used in a specific application example.

[0090] Figure 13a The image schematically illustrates the pre-stack depth migration results of a CMP gather without any static correction using the I-model.

[0091] Figure 13b The image schematically illustrates the pre-stack depth migration results of the CMP gather after high-frequency static correction using the S-model.

[0092] Figure 14a Schematic illustration Figure 13a A magnified view of the left side of the middle section;

[0093] Figure 14b Schematic illustration Figure 13b A magnified view of the left side of the middle section;

[0094] Figure 15 A schematic block diagram illustrating the composition of a gather correction apparatus according to an embodiment of this application is shown.

[0095] Figure 16 A schematic block diagram of a computer device according to an embodiment of this application is shown. Detailed Implementation

[0096] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the embodiments of this application.

[0097] If the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0098] Literature review and practical investigation revealed that some researchers directly smooth the composite static correction in the time domain when calculating high-frequency static corrections. One existing technique discloses a gather correction method that smooths the composite static correction at a preset spatial scale to obtain a low-frequency static correction, then subtracts the calculated low-frequency static correction from the total static correction to obtain the high-frequency static correction. However, this method of calculating high-frequency static corrections lacks physical meaning, and subsequent processing of near-surface models is difficult to maintain consistently, presenting numerous problems.

[0099] To overcome the above-mentioned defects, Figure 1 A flowchart illustrating a gather correction method according to an embodiment of this application is shown schematically. Figure 1 As shown, the gather correction method may include steps 102 to 104.

[0100] Step 102: Through matching analysis of the underground real model of the target work area, the initial near-surface velocity model, the smoothed model used for pre-stack depth migration, and the travel time, determine the difference between the static correction of the initial near-surface velocity model and the static correction of the smoothed model. The sum of the obtained first-arrival residual static correction of the initial near-surface velocity model and the difference as described above is taken as the high-frequency static correction. The smoothed model is obtained by preprocessing the initial near-surface velocity model. The static correction calculation using the initial near-surface velocity model uses the real terrain surface of the target work area as the depth migration surface, and the static correction calculation using the smoothed model uses the target terrain surface as the depth migration surface. The types of target terrain surfaces include smoothed real terrain surfaces and smoothed terrain surfaces.

[0101] As an example, preprocessing may include smoothing out speed anomalies, separating speeds below a first lower limit, such as ultra-low speed separation.

[0102] As an optional embodiment of this application, the type of target terrain surface also includes the submersion of the terrain surface.

[0103] As an example, the appropriate processing of the real terrain surface can be determined based on different levels of surface complexity to obtain the target terrain surface as a depth offset surface for the smoothing model. For example, if the real terrain surface is smooth, it can be used as the depth offset surface. If the real terrain surface is not smooth, small-scale smoothing of the real terrain surface can be performed. Depending on the surface condition, the subsidence of the real terrain surface can sometimes be used as the depth offset surface.

[0104] Step 104: Use the high-frequency static correction amount obtained in step 102 to correct the CMP gather (common center point gather) of the target work area that has not undergone any static correction processing, so as to use it for pre-stack depth migration or full depth domain velocity modeling of the target work area.

[0105] Specifically, in this application, the initial near-surface velocity model and the specific static corrections calculated using this model can be obtained through known and disclosed static correction calculation methods or procedures. Specifically, the model static corrections and first-arrival / residual static corrections calculated using the initial near-surface velocity model can both be obtained through these static correction calculation methods or procedures. As stated above, this application inherits and uses known and disclosed static correction calculation methods or procedures; that is, the high-frequency static corrections for the matched smoothing model and travel time calculated in this application inherit the calculation results of these known and disclosed static correction calculation methods or procedures.

[0106] To illustrate the differences between the actual underground model, the initial near-surface velocity model, and the smoothed model of the target work area, in one example, such as Figures 4a-4c As shown, Figure 4a A theoretical underground model of the target work area is shown. Figure 4b The initial near-surface velocity model of the target work area is shown. It can be seen that the initial near-surface velocity model can be obtained using near-surface velocity inversion methods. Different near-surface inversion methods have varying degrees of accuracy. Some inverted near-surface velocity models are close to the actual subsurface model, while others are far from it. However, all inverted near-surface velocity models show discrepancies with the actual subsurface model. Figure 4c The smoothing model of the target work area is shown. The smoothing model only takes the reasonable part of the initial near-surface velocity model. That is, the preprocessing of the initial near-surface velocity model should include at least the smoothing of velocity anomalies. Figures 4a-4c In this context, SRD represents the preset fixed reference surface, Topo represents the real terrain surface, FD represents the depth offset surface of the smooth model, and HVI represents the high-speed layer top interface.

[0107] As in the above embodiment, through matching analysis of the subsurface real model, the initial near-surface velocity model, the smoothed model, and travel time, the model static correction difference between the initial near-surface velocity model and the smoothed model is determined. That is, the difference between the model static correction of the initial near-surface velocity model and the model static correction of the smoothed model. Then, considering the pre-stack application of the first-arrival residual static correction, the high-frequency static correction for CMP gather correction is calculated. Applying this high-frequency static correction to correct CMP gathers that have not undergone any static correction improves the matching degree between the seismic wavefield travel time and the near-surface velocity model. Using the corrected CMP gathers and the smoothed model for pre-stack depth migration velocity modeling and imaging improves both the modeling and imaging quality. The improvement in pre-stack depth migration velocity modeling and imaging quality specifically refers to: using corrected CMP gathers and smoothed models for pre-stack depth migration near-surface imaging, resulting in improved near-surface imaging results; and linking mid- and deep velocity modeling and imaging based on this, that is, incorporating the smoothed model into full-depth pre-stack depth migration velocity modeling, leading to improvements in the near-surface velocity structure in the depth domain velocity model. Based on this, mid- and deep velocity modeling can better adapt to zero-bias VSP velocities, sonic logging velocities, etc., thus improving the overall rationality of the depth domain velocity model and the imaging effect of deep targets, resulting in a more reasonable full-depth velocity model and more accurate deep target imaging. It is known that the model static correction is the portion of static correction calculated using the model, that is, the static correction calculated from the model's depth migration surface to a preset fixed reference surface. For example, the model static correction of the smoothed model is the static correction of the shot point or receiver point in the target area from the target terrain surface, which is used as the depth migration surface, to the preset fixed reference surface.

[0108] In summary, this application, through the matching analysis of near-surface velocity model and travel time, utilizes the constructed initial near-surface velocity model, the model static correction amount calculated using the initial near-surface velocity model, and the first-arrival residual static correction amount to derive the high-frequency static correction amount when performing static correction using a smooth model. The high-frequency static correction amount calculated in this way has practical physical meaning. Applying this high-frequency static correction amount for CMP gather correction improves the matching degree between seismic wavefield travel time and near-surface model, thereby improving the pre-stack depth migration velocity modeling and imaging effect, which is particularly suitable for improving the imaging quality of deep geological targets in dual complex exploration areas.

[0109] As an example, the high-frequency static correction includes the high-frequency static correction of the shot point and the high-frequency static correction of the receiver point within the target work area.

[0110] As an optional embodiment of this application, the static correction amount of the smoothing model is determined by describing the travel time changes, and correspondingly, the static correction amount of the smoothing model is calculated by the following formula:

[0111] stS =tt SRD -tt model (Formula 1);

[0112] In formula 1, tt SRD This indicates the travel time of a shot point or receiver within the target work area from a preset fixed reference plane to the high-speed layer top interface; st S The static correction amount for the shot point model or receiver point model in the smoothing model; HVI-SRD represents the distance between the high-velocity layer top interface and the preset fixed reference plane, v replace Indicates the replacement speed; tt model When representing the travel distance from the target terrain surface (serving as a depth offset surface) to the top interface of the high-velocity layer, dl and dv represent the depth-direction mesh size and the wave velocity within the mesh in the smoothed model after meshing, respectively. This represents the integral from the target terrain surface, which serves as the depth offset surface, to the top interface of the high-velocity layer.

[0113] As an optional embodiment of this application, the matching analysis of the underground real model, initial near-surface velocity model, smoothing model, and travel time of the target work area is achieved in the following manner:

[0114] Determine the travel time tt from the preset fixed reference surface to the top interface of the high-velocity layer for the underground real model, the initial near-surface velocity model, and the smoothed model, respectively. T tt I tt S ,in,

[0115] According to the time tt T 、Time travel I 、Time travel S The formula for correcting the trace collection is derived.

[0116] Determine the expression for the high-frequency static correction amount used to correct CMP gathers that have not undergone any static correction processing.

[0117] Wherein, Topo-SRD represents the distance between the actual terrain surface and the preset fixed reference surface; FD-SRD represents the distance between the target terrain surface, which serves as the depth offset surface, and the preset fixed reference surface; This represents the integral from the real terrain surface to the top interface of the high-speed layer; This represents the travel time from the real terrain surface to the top of the high-velocity layer in the initial near-surface velocity model; This represents the travel time from the real terrain surface to the top interface of the high-speed layer in the underground realistic model; stI This represents the static correction of the initial near-surface velocity model; data s This represents the CMP gather after high-frequency static correction; data T This indicates a CMP gather that has not undergone any static correction. Indicates the initial and remaining static correction amount; dv T dv I dv S These represent the wave velocities within the meshes of the real subsurface model, the initial near-surface velocity model, and the smoothed model, respectively; st high This indicates the high-frequency static correction amount.

[0118] As an optional embodiment, based on the time tt T 、Time travel I 、Time travel S The gather correction formula is derived, including:

[0119] Establish the first equation tt S -tt T =tt S -tt I +tt I -tt T ;

[0120] Add to both sides of the first equation Expanding the terms on the right side of the first equation, we obtain the second equation.

[0121] Except for tt, the left side of the second equation S Move all other terms to the right to obtain the third equation.

[0122] Moving the shot receiver position from the fixed reference plane to the depth offset plane yields the fourth equation.

[0123] because Express the fourth equation as the fifth equation.

[0124] Simplifying the fifth equation yields the correction formula for the collection of passages.

[0125] Wherein, HVI-FD represents the distance between the high-velocity top interface and the target terrain surface; HVI-Topo represents the distance between the high-velocity top interface and the real terrain surface.

[0126] As in the above embodiments, for the underground real model and the initial near-surface velocity model, the shot point and receiver point are located on the actual terrain surface, that is, the shot point depth factor is not considered, and it is assumed that the low-velocity zone ray conforms to the plumb line incident characteristics. To achieve more refined considerations, such as considering the shot point depth and using lidar in the actual measurement of the initial near-surface velocity model to obtain more accurate terrain, the above embodiments can be improved, but these improved embodiments do not depart from the inventive concept of this application.

[0127] Based on the above gather correction method, this application also provides a pre-stack depth migration method, which achieves pre-stack depth migration in the following manner:

[0128] A smoothing model of the target work area is constructed. The smoothing model is obtained by preprocessing the initial near-surface velocity model of the target work area.

[0129] Using the target terrain surface as the depth migration surface, pre-stack depth migration is performed using the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing based on the gather correction method described in the previous embodiments. The types of target terrain surfaces include smooth real terrain surfaces and smoothed terrain surfaces.

[0130] As in the above embodiment, the imaging quality of pre-stack depth migration is improved by using CMP gathers and smoothing models with improved matching degree between seismic travel time and near-surface velocity models.

[0131] Figure 2 A flowchart illustrating a pre-stack depth offset method according to an embodiment of this application is shown schematically. Figure 2 As shown, the pre-stack depth migration method is based on the gather correction method described in the previous embodiments, specifically including steps 202 to 208.

[0132] Step 202: Construct a smoothing model for the target work area. The smoothing model is obtained by preprocessing the initial near-surface velocity model of the target work area.

[0133] Step 204: Through matching analysis of the underground real model, initial near-surface velocity model, smoothing model and travel time of the target work area, determine the difference between the static correction amount of the initial near-surface velocity model and the static correction amount of the smoothing model. The sum of the initial arrival residual static correction amount after static correction using the initial near-surface velocity model and the aforementioned difference value is taken as the high-frequency static correction amount. The static correction calculation using the initial near-surface velocity model uses the real terrain surface of the target work area as the depth offset surface, and the static correction calculation using the smoothing model uses the target terrain surface as the depth offset surface. The type of target terrain surface includes smoothed real terrain surface and smoothed terrain surface.

[0134] Step 206: Use the high-frequency static correction amount obtained in step 204 to correct the CMP gather in the target work area that has not undergone any static correction treatment.

[0135] Step 208: Using the target terrain surface as the depth migration surface, perform pre-stack depth migration using the corrected CMP gather and smoothing model.

[0136] Based on the above gather correction method, this application also provides a full-depth-domain velocity modeling method, which achieves full-depth-domain velocity modeling in the following way:

[0137] A smoothing model of the target work area is constructed. The smoothing model is obtained by preprocessing the initial near-surface velocity model.

[0138] The full depth domain velocity modeling of the target work area is carried out using the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing based on the gather correction method described in the previous embodiments.

[0139] As in the above embodiment, by using the CMP gather and smoothing model with improved matching degree between seismic travel time and near-surface velocity model, full-depth domain velocity modeling for pre-stack depth migration is performed. The near-surface velocity structure in the velocity modeling results is improved, and the zero-bias VSP velocity, sonic logging velocity, etc. are better adapted when modeling the mid-deep velocity, thus obtaining a more reasonable depth domain velocity model as a whole.

[0140] Figure 3 A flowchart illustrating a full-depth-domain velocity modeling method according to an embodiment of this application is shown schematically. Figure 3 As shown, the full depth domain velocity modeling method is based on the gather correction method described in the previous embodiments, specifically including steps 302 to 308.

[0141] Step 302: Construct a smoothing model for the target work area. The smoothing model is obtained by preprocessing the initial near-surface velocity model.

[0142] Step 304: Through matching analysis of the underground real model, initial near-surface velocity model, smoothing model and travel time of the target work area, determine the difference between the static correction amount of the initial near-surface velocity model and the static correction amount of the smoothing model. The sum of the initial arrival residual static correction amount after static correction using the initial near-surface velocity model and the aforementioned difference value is taken as the high-frequency static correction amount. The static correction calculation using the initial near-surface velocity model uses the real terrain surface of the target work area as the depth offset surface, and the static correction calculation using the smoothing model uses the target terrain surface as the depth offset surface. The type of target terrain surface includes smoothed real terrain surface and smoothed terrain surface.

[0143] Step 306: Use the high-frequency static correction amount obtained in step 304 to correct the CMP gather in the target work area that has not undergone any static correction treatment.

[0144] Step 308: Use the corrected CMP gather and smoothing model to perform full-depth domain velocity modeling of the target work area.

[0145] In a specific application example, combined with Figures 5 to 14b As shown, this application example provides a pre-stack depth offset method for work area A, which mainly includes steps B1 to B5.

[0146] Step B1, Data Preparation.

[0147] Specifically, it includes the following sub-steps:

[0148] Collect CMP gathers in work area A that have not undergone any static correction.

[0149] Collect the coordinates and elevation information of the shot points and receiver points in work area A;

[0150] Collect the initial near-surface velocity model and static correction information obtained from the inversion of work area A.

[0151] The near-surface velocity model and static corrections can be calculated using known methods or software programs for calculating the initial near-surface velocity model (I model) and static corrections. This application example does not specify which known method or software program to use. Collecting the initial near-surface velocity model and static correction information for work area A specifically refers to collecting the initial near-surface velocity model, replacement velocity, high-velocity top interface, receiver model static correction, receiver first-arrival residual static correction, shot point model static correction, and shot point first-arrival residual static correction.

[0152] After data preparation, all collected data are loaded into a publicly available pre-stack depth migration velocity modeling and imaging program. A fixed reference surface (SRD) is established, and a depth migration surface (FD) is created. The depth migration surface is the result of properly processing the real terrain surface of work area A. Depending on specific needs and different surface complexities, the properly processed terrain surface can be a smoothed real terrain surface (Topo), a small-scale smoothed terrain surface, or a terrain subsidence, etc. Next, the initial near-surface velocity model is processed. The processed near-surface velocity model serves as the smoothed model (S-model) as described above. It only takes the reasonable part of the I-model, that is, the velocity anomalies in the I-model need to be smoothed, etc. The method of obtaining the smoothed model through preprocessing can be determined according to the processing requirements of the work area. For example, in this application example, the smoothed model can be the originally imported I-model, the near-surface velocity model obtained after smoothing the I-model, or the near-surface velocity model after ultra-low velocity separation of the I-model, etc. Finally, the high-velocity top interface, shot point static correction, and receiver point static correction are loaded, and meshing is performed. Figure 6a This schematically illustrates a diagram of the initial near-surface velocity model obtained through inversion. Figure 6a It can be seen that the initial near-surface velocity model contains patchy anomalies close to the surface. Figure 6a The smoothed model obtained after smoothing the initial near-surface velocity model shown is as follows: Figure 6b As shown, the solid black lines on the smoothed model represent the terrain lines and the high-velocity layer top interface. This application example uses true surface migration, meaning the meshed terrain surface determined based on the shot point, receiver coordinates, and elevation information is directly used as the depth migration surface. This depth migration surface is shown below. Figure 7 As shown. The collected high-speed layer top interface, after meshing, is as follows. Figure 8 As shown. In this application example, the replacement velocity is set to 2000 m / s, and the fixed reference plane is set to -4000 m. The collected receiver point synthetic static correction values ​​of the I model are as follows. Figure 9a As shown, the collected receiver point model static correction values ​​of the I model are as follows: Figure 9b As shown, the collected static correction values ​​for the shot points of Model I (not shown in the figure) are similar to those for the receiver points.

[0153] Step B2, calculate the static correction of the S-model. Specifically, this means: calculating the static correction of the S-model using Equation 1 above. The static correction of the shot point model of the S-model is the static correction of the shot point from the depth offset plane to the fixed reference plane, and the static correction of the receiver point model of the S-model is the static correction of the receiver point from the depth offset plane to the fixed reference plane.

[0154] The calculation process for Equation 1 is as follows: First, calculate the two-way travel time from the fixed reference plane SRD to the depth offset plane FD at the replacement velocity. See [link to Equation 1] for details. Figure 10a As shown, the two-way travel time from the depth offset plane FD to the high-velocity layer top interface HVI at the replacement velocity is then calculated. See [link to details]. Figure 10c As shown, the two-way travel time from the depth migration plane FD to the high-velocity layer top interface HVI under the S-model is then calculated. See [link to details]. Figure 10b As shown, by replacing the two-way travel time in the above calculation results with the single-layer travel time, and then substituting it into Equation 1, the static correction of the S-model can be calculated. The calculation results are shown in [reference needed]. Figure 9c As shown.

[0155] Step B3: Calculate the high-frequency static correction. Specifically, in the true surface modeling process, static correction is used to match the model and travel time. Since subsequent pre-stack depth migration imaging uses the S-model, the CMP gathers acquired in step B1 without any static correction correspond to the actual underground model travel time. Since the travel time does not match the model, the calculated high-frequency static correction ensures that the CMP gathers, after correction, achieve travel time matching with the model. Specifically, the high-frequency static correction is calculated using the expression derived above: substituting the known static correction of the I-model, the static correction of the S-model calculated in step B2, and the known first-arrival residual static correction of the I-model into this expression yields the high-frequency static correction used for matching the model and travel time.

[0156] Step B4, apply high-frequency static correction. Specifically, this means applying high-frequency static corrections for the shot point and receiver point to the CMP gather in work area A that has not undergone any static correction, to obtain the CMP gather after applying the high-frequency static corrections. The CMP gather in work area A without any static correction is shown below. Figure 11a As shown, the CMP gather after applying high-frequency static correction is as follows: Figure 11b As shown, the applied high-frequency static correction amount is as follows: Figure 12 As shown.

[0157] Step B5, pre-stack depth migration imaging. Specifically, this refers to performing pre-stack depth migration imaging on the CMP gather obtained in step B4 after applying high-frequency static correction using an S-model. The imaging results are as follows: Figure 13b As shown in the figure, for comparison, pre-stack depth migration imaging was performed on a CMP gather without any static correction using the I model. The imaging results are as follows. Figure 13a As shown, Figure 14a for Figure 13a A magnified view of the details in the left-hand image. Figure 14b for Figure 13b A magnified view of the details in the left-hand image. Figure 13a , Figure 13b , Figure 14a and Figure 14b The solid black lines on the image shown are depth offset planes, and the profile positions are as follows: Figure 12 As shown by a medium-thick solid line. Combined with... Figure 13a , Figure 13b , Figure 14a and Figure 14b It can be seen that, through the calculation and application of high-frequency static correction, the near-surface imaging results of the CMP gather using the S-model for pre-stack depth migration imaging have been significantly improved.

[0158] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0159] Corresponding to the gather correction method in the above embodiments, such as Figure 15 As shown, this application embodiment also provides a pre-stack depth migration imaging device 500, including:

[0160] The high-frequency static correction calculation module 510 is used to determine the difference between the static correction of the initial near-surface velocity model and the static correction of the smoothed model by matching analysis of the underground real model of the target work area, the initial near-surface velocity model, the smoothed model used for pre-stack depth migration, and the travel time. The module uses the sum of the initial arrival residual static correction after static correction using the initial near-surface velocity model and the difference value as the high-frequency static correction. The smoothed model is obtained by preprocessing the initial near-surface velocity model. The static correction calculation using the initial near-surface velocity model uses the real terrain surface of the target work area as the depth migration surface, and the static correction calculation using the smoothed model uses the target terrain surface as the depth migration surface. The type of the target terrain surface includes a smoothed real terrain surface and a smoothed terrain surface.

[0161] The gather correction module 520 is used to correct the CMP gather in the target work area that has not undergone any static correction processing using the high-frequency static correction amount.

[0162] As one embodiment of this application, the gather correction device can achieve the following: Figure 1 The embodiments shown are as well as other related method embodiments in this application.

[0163] For details on how each module in the road gather correction device 500 provided in this application implements its respective function, please refer to the foregoing. Figure 1 The descriptions of the embodiments shown and other related method embodiments are not repeated here.

[0164] Corresponding to the pre-stack depth migration method in the above embodiments, this application also provides a pre-stack depth migration device, including:

[0165] The first construction module is used to construct a smooth model of the target work area. The smooth model is obtained by preprocessing the initial near-surface velocity model.

[0166] The pre-stack depth migration module is used to perform pre-stack depth migration using the target terrain surface as the depth migration surface and the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing based on the gather correction method described in the above embodiments of this application. The type of the target terrain surface includes a smooth real terrain surface and a smoothed terrain surface.

[0167] As an embodiment of this application, the pre-stack depth offset device can achieve the following: Figure 2 The embodiments shown are as well as other related method embodiments in this application.

[0168] The process by which each module in the pre-stack depth migration device provided in this application implements its respective function can be specifically referred to the foregoing. Figure 2 The descriptions of the embodiments shown and other related method embodiments are not repeated here.

[0169] Corresponding to the full-depth-domain velocity modeling method in the above embodiments, this application also provides a full-depth-domain velocity modeling apparatus, including:

[0170] The second construction module is used to construct a smoothing model of the target work area. The smoothing model is obtained by preprocessing the initial near-surface velocity model.

[0171] The velocity modeling module is used to perform full-depth domain velocity modeling of the target work area using the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area that has not undergone any static correction processing based on the gather correction method described in the above embodiments of this application.

[0172] As one embodiment of this application, the full-depth-domain velocity modeling device can achieve the following: Figure 3 The embodiments shown are as well as other related method embodiments in this application.

[0173] The process by which each module in the full-depth domain velocity modeling device provided in this application implements its respective function can be found in the foregoing. Figure 3 The descriptions of the embodiments shown and other related method embodiments are not repeated here.

[0174] It should be noted that the information interaction and execution process between the above modules are based on the same concept as the method embodiments of this application. Their specific functions and technical effects can be found in the method embodiments section, and will not be repeated here. Furthermore, all of the above modules can be applied to computing devices that include memory and a processor.

[0175] Figure 16 A schematic block diagram of a computer device according to an embodiment of the present application is shown. In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as shown below. Figure 16 As shown in the figure, the computer device includes a processor A01, a network interface A02, a display screen A04, an input device A05, and a memory (not shown) connected via a system bus. The processor A01 provides computing and control capabilities. The memory includes internal memory A03 and a non-volatile storage medium A06. The non-volatile storage medium A06 stores an operating system B01 and a computer program B02. The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 stored in the non-volatile storage medium A06. The network interface A02 is used for communication with external terminals via a network connection. When the computer program is executed by the processor A01, it implements a gather correction method, a pre-stack depth migration method, or a full-depth domain velocity modeling method. The display screen A04 can be a liquid crystal display (LCD) or an e-ink display. The input device A05 can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0176] Those skilled in the art will understand that Figure 16 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0177] In one embodiment, the gather correction device, pre-stack depth migration device, and full-depth-domain velocity modeling device provided in this application can be implemented as a computer program. The computer program can be implemented in various ways, such as... Figure 16 The computer device shown operates on this device. The computer device's memory can store various program modules that constitute the gather correction device, the pre-stack depth migration device, and the full-depth-domain velocity modeling device. The computer program, composed of these program modules, causes the processor to execute steps in the gather correction method, the pre-stack depth migration method, or the full-depth-domain velocity modeling method described in the various embodiments of this application.

[0178] In one embodiment, this application also provides a machine-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the gather correction method, the pre-stack depth migration method, or the full depth domain velocity modeling method in the above embodiments.

[0179] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0180] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0181] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0182] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for correcting road collections, characterized in that, include: By matching analysis of the underground real model of the target work area, the obtained initial near-surface velocity model, the smoothed model used for pre-stack depth migration, and the travel time, the difference between the static correction of the initial near-surface velocity model and the static correction of the smoothed model is determined. The sum of the initial arrival residual static correction after static correction using the initial near-surface velocity model and the difference is taken as the high-frequency static correction. The smoothed model is obtained by preprocessing the initial near-surface velocity model. The static correction calculation using the initial near-surface velocity model uses the real terrain surface of the target work area as the depth migration surface, and the static correction calculation using the smoothed model uses the target terrain surface as the depth migration surface. The type of the target terrain surface includes a smoothed real terrain surface and a smoothed terrain surface. The high-frequency static correction amount is used to correct the CMP gather in the target work area that has not undergone any static correction treatment.

2. The gather correction method according to claim 1, characterized in that, The static correction of the smoothed model is calculated using the following formula: pcs S =tt SRD -tt model ; Among them, st S This represents the static correction amount of the model for shot points or receiver points within the target work area; tt SRD HVI-SRD represents the distance between the high-velocity layer top interface and the fixed reference plane when the shot point or receiver point travels from a preset fixed reference plane to the high-velocity layer top interface. replace Indicates the replacement speed; tt model When representing the travel distance from the target terrain surface to the top interface of the high-velocity layer, dl and dv represent the depth direction mesh size and the wave velocity within the mesh in the smoothed model after meshing, respectively. This represents the integral from the target terrain surface to the top interface of the high-speed layer.

3. The gather correction method according to claim 1, characterized in that, The initial near-surface velocity model is a near-surface velocity model obtained using the near-surface velocity inversion method.

4. The gather correction method according to claim 2, characterized in that, Matching analysis of the target work area's underground real model, initial near-surface velocity model, smoothing model, and travel time, including: The travel time tt of the underground real model, the initial near-surface velocity model, and the smoothed model of the target work area from the fixed reference surface to the top interface of the high-velocity layer are determined respectively. T 、Time travel I 、Time travel S ; According to the time tt T 、Time travel I 、Time travel S The formula for correcting the trace collection is derived. Determine the expression for the high-frequency static correction amount used to correct CMP gathers that have not undergone any static correction processing. in, Topo-SRD represents the distance between the actual terrain surface and the fixed reference surface; FD-SRD represents the distance between the target terrain surface and the fixed reference surface; This represents the integral from the real terrain surface to the top interface of the high-speed layer; st I This represents the static correction value of the initial near-surface velocity model; data s This represents the CMP gather after high-frequency static correction; data T This indicates a CMP gather that has not undergone any static correction. This represents the initial arrival residual static correction amount after static correction using the initial near-surface velocity model; dv T dv I dv S These represent the wave velocities within the meshes of the actual underground model, the initial near-surface velocity model, and the smoothed model, respectively; st high This indicates the high-frequency static correction amount.

5. The gather correction method according to claim 4, characterized in that, According to the time tt T 、Time travel I 、Time travel S The gather correction formula is derived, including: Establish the first equation tt S -tt T =tt S -tt I +tt I -tt T ; Add to both sides of the first equation Expanding the terms on the right side of the first equation, we obtain the second equation. Except for tt, the left side of the second equation S Move all other terms to the right to obtain the third equation. Moving the shot receiver position from the fixed reference plane to the depth offset plane yields the fourth equation. because Express the fourth equation as the fifth equation. Simplifying the fifth equation yields the correction formula for the collection of passages. Wherein, HVI-FD represents the distance between the high-velocity top interface and the target terrain surface; HVI-Topo represents the distance between the high-velocity top interface and the real terrain surface.

6. The gather correction method according to claim 1, characterized in that, The type of target terrain surface also includes the submersion of the terrain surface.

7. The gather correction method according to claim 1, characterized in that, The preprocessing includes at least one of smoothing out velocity anomalies and velocity separation below a first lower limit.

8. A pre-stack depth migration method, characterized in that, include: A smoothing model of the target work area is constructed, which is obtained by preprocessing the initial near-surface velocity model. Using the target terrain surface as the depth offset surface, pre-stack depth offset is performed using the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing based on the gather correction method according to any one of claims 1 to 7. The type of the target terrain surface includes a smooth real terrain surface and a smoothed terrain surface.

9. A method for velocity modeling across the entire depth domain, characterized in that, include: A smoothing model of the target work area is constructed, which is obtained by preprocessing the initial near-surface velocity model. The full depth domain velocity modeling of the target work area is performed using the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing based on the gather correction method according to any one of claims 1 to 7.

10. A road convergence correction device, characterized in that, include: The high-frequency static correction calculation module is used to determine the difference between the static correction of the initial near-surface velocity model and the static correction of the smoothed model by using the underground real model of the target work area, the obtained initial near-surface velocity model, the smoothed model used for pre-stack depth migration, and the travel time matching analysis. The sum of the obtained initial arrival residual static correction after static correction using the initial near-surface velocity model and the difference value is used as the high-frequency static correction. The smoothed model is obtained by preprocessing the initial near-surface velocity model. The static correction calculation using the initial near-surface velocity model uses the real terrain surface of the target work area as the depth migration surface, and the static correction calculation using the smoothed model uses the target terrain surface as the depth migration surface. The type of the target terrain surface includes a smoothed real terrain surface and a smoothed terrain surface. The gather correction module is used to correct the CMP gathers in the target work area that have not undergone any static correction processing using the high-frequency static correction amount.

11. The road gather correction device according to claim 10, characterized in that, The static correction of the smoothed model is calculated using the following formula: pcs S =tt SRD -tt model ; Among them, st S This represents the static correction amount of the model for shot points or receiver points within the target work area; tt SRD HVI-SRD represents the distance between the high-velocity layer top interface and the fixed reference plane when the shot point or receiver point travels from a preset fixed reference plane to the high-velocity layer top interface. replace Indicates the replacement speed; tt model When representing the travel distance from the target terrain surface to the top interface of the high-velocity layer, dl and dv represent the depth direction mesh size and the wave velocity within the mesh in the smoothed model after meshing, respectively. This represents the integral from the target terrain surface to the top interface of the high-speed layer.

12. The road gather correction device according to claim 10, characterized in that, The initial near-surface velocity model is a near-surface velocity model obtained using the near-surface velocity inversion method.

13. The road gather correction device according to claim 11, characterized in that, Matching analysis of the target work area's underground real model, initial near-surface velocity model, smoothing model, and travel time, including: The travel time tt of the underground real model, the initial near-surface velocity model, and the smoothed model of the target work area from the fixed reference surface to the top interface of the high-velocity layer are determined respectively. T 、Time travel I 、Time travel S ; According to the time tt T 、Time travel I 、Time travel S The formula for correcting the trace collection is derived. Determine the expression for the high-frequency static correction amount used to correct CMP gathers that have not undergone any static correction processing. in, Topo-SRD represents the distance between the actual terrain surface and the fixed reference surface; FD-SRD represents the distance between the target terrain surface and the fixed reference surface; This represents the integral from the real terrain surface to the top interface of the high-speed layer; st I This represents the static correction value of the initial near-surface velocity model; data s This represents the CMP gather after high-frequency static correction; data T This indicates a CMP gather that has not undergone any static correction. This represents the initial arrival residual static correction amount after static correction using the initial near-surface velocity model; dv T dv I dv S These represent the wave velocities within the meshes of the actual underground model, the initial near-surface velocity model, and the smoothed model, respectively; st high This indicates the high-frequency static correction amount.

14. The road gather correction device according to claim 13, characterized in that, According to the time tt T 、Time travel I 、Time travel S The gather correction formula is derived, including: Establish the first equation tt S -tt T =tt S -tt I +tt I -tt T ; Add to both sides of the first equation Expanding the terms on the right side of the first equation, we obtain the second equation. Except for tt, the left side of the second equation S Move all other terms to the right to obtain the third equation. Moving the shot receiver position from the fixed reference plane to the depth offset plane yields the fourth equation. because Express the fourth equation as the fifth equation. Simplifying the fifth equation yields the correction formula for the collection of passages. Wherein, HVI-FD represents the distance between the high-velocity top interface and the target terrain surface; HVI-Topo represents the distance between the high-velocity top interface and the real terrain surface.

15. The road gather correction device according to claim 10, characterized in that, The type of target terrain surface also includes the submersion of the terrain surface.

16. The road gather correction device according to claim 10, characterized in that, The preprocessing includes at least one of smoothing out velocity anomalies and separating velocities below a first lower limit.

17. A pre-stack depth offset device, characterized in that, include: The first construction module is used to construct a smooth model of the target work area. The smooth model is obtained by preprocessing the initial near-surface velocity model. The pre-stack depth migration module is used to perform pre-stack depth migration using the target terrain surface as the depth migration surface and the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing based on the gather correction method according to any one of claims 1 to 7. The type of the target terrain surface includes a smooth real terrain surface and a smoothed terrain surface.

18. A velocity modeling device for the entire depth domain, characterized in that, include: The second construction module is used to construct a smoothing model of the target work area. The smoothing model is obtained by preprocessing the initial near-surface velocity model. The velocity modeling module is used to perform full-depth domain velocity modeling of the target work area using the corrected CMP gather and the smoothing model. The corrected CMP gather is obtained by correcting the CMP gather of the target work area without any static correction processing based on the gather correction method according to any one of claims 1 to 7.

19. A computer device, characterized in that, include: The memory is configured to store instructions; as well as The processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the gather correction method according to any one of claims 1 to 7, the pre-stack depth migration method according to claim 8, or the full depth domain velocity modeling method according to claim 9.

20. A machine-readable storage medium, characterized in that, The machine-readable storage medium stores instructions for causing the machine to perform the gather correction method according to any one of claims 1 to 7, the pre-stack depth migration method according to claim 8, or the full depth domain velocity modeling method according to claim 9.

Images