Method, device and storage medium for determining a velocity model

Abstract

The application discloses a speed model determination method and device, equipment and a storage medium, and belongs to the technical field of seismic data. The method comprises the following steps: determining an adjusted speed value of a grid region based on prior information of a partial region and an interpolation algorithm; determining a first updated speed model based on an iterative weight value, the adjusted speed value and an initial speed model; determining a propagation distance of a first arrival wave in each target grid region; determining a speed update difference value of a target grid region based on a travel time of the first arrival wave, the propagation distance of the first arrival wave in the target grid region and the first updated speed value of the target grid region; updating the first updated speed model based on the speed update difference value of the target grid region to obtain a second updated speed model; and if a preset condition is met, determining the second updated speed model as the speed model, and if the preset condition is not met, determining the second updated speed model as the initial speed model. The application improves the accuracy of the speed model.

Description

Technical Field

[0001] This application relates to the field of seismic data technology, and in particular to a method, apparatus, device, and storage medium for determining a velocity model. Background Technology

[0002] Velocity models are an important component in seismic data processing, and their accuracy directly affects the processing results.

[0003] Currently, after establishing an initial velocity model, tomographic inversion is usually used to adjust the initial velocity values ​​in the initial velocity model to obtain a more accurate velocity model.

[0004] However, the accuracy of the velocity model obtained by the above method is still low. Summary of the Invention

[0005] This application provides a method for determining a velocity model, which can solve the problem of low accuracy of velocity models in the prior art.

[0006] Firstly, a method for determining a velocity model is provided, the method comprising:

[0007] Obtain the initial velocity model corresponding to the target area, wherein the initial velocity model includes multiple data channels with different position coordinates, and each data channel includes at least one grid region corresponding to a different depth and an initial velocity value corresponding to each grid region;

[0008] Based on prior information and interpolation algorithms for some regions within the target region, the adjustment speed values ​​corresponding to multiple grid regions within the target region are determined;

[0009] Based on the initial iteration weight value and the current iteration number, the iteration weight value corresponding to the current iteration number is determined, wherein the initial iteration weight value is the iteration weight value corresponding to the first iteration, and the iteration weight value corresponding to the current iteration number is negatively correlated with the current iteration number;

[0010] Based on the iteration weight value corresponding to the current iteration number, the adjustment speed value corresponding to the multiple grid regions, and the initial speed model, a first update speed model is determined, wherein the first update speed model includes the first update speed value corresponding to the initial speed value of the multiple grid regions;

[0011] The travel times of multiple first arrival waves corresponding to the target area are obtained, wherein the travel times of the multiple first arrival waves are obtained through seismic data corresponding to the target area;

[0012] Based on the ray tracing algorithm, the first update velocity model, and the source point coordinates and multiple receiver coordinates in the seismic data corresponding to the target area, the propagation distance of each first arrival wave in each target grid area is determined.

[0013] Based on the travel time of the multiple first arrival waves, the propagation distance of each first arrival wave in the target grid region it passes through, and the first update rate value of each target grid region corresponding to the multiple first arrival waves, the speed update difference corresponding to the first update rate value of each target grid region is determined.

[0014] Based on the speed update difference corresponding to the first update speed value of each target grid region, the first update speed model is updated to obtain a second update speed model, wherein the second update speed model includes the second update speed value corresponding to the first update speed value of the plurality of grid regions;

[0015] If the preset conditions are met, the iteration stops and the second update speed model is determined as the speed model. If the preset conditions are not met, the second update speed model is determined as the initial speed model.

[0016] In one possible implementation, the prior information of the partial region includes the layer information corresponding to each well logging in the partial region and the actual velocity value corresponding to each layer, wherein the layer information corresponding to the well logging includes the depth of at least one layer corresponding to the well logging.

[0017] The step of determining the adjustment speed values ​​corresponding to multiple grid regions in the target region based on prior information and interpolation algorithms of a portion of the target region includes:

[0018] Determine at least one logging grid area included in the data channel corresponding to each well log;

[0019] Based on the stratigraphic information corresponding to each well log and the depth corresponding to each well log grid area, the stratigraphic level to which each well log grid area belongs is determined;

[0020] For each logging grid area corresponding to each logging, the actual velocity value corresponding to the layer to which the logging grid area belongs is determined as the adjusted velocity value corresponding to the logging grid area;

[0021] Based on the adjustment velocity value corresponding to each logging grid area and the interpolation algorithm, the adjustment velocity values ​​corresponding to other grid areas in the target area besides the logging grid areas are determined.

[0022] In one possible implementation, determining the iteration weight value corresponding to the current iteration number based on the initial iteration weight value and the current iteration number includes:

[0023] The iteration weight value corresponding to the current iteration number is calculated based on the following formula:

[0024] m i -m1=b*(i-1)

[0025] Where i is the current iteration number, and m i is the iteration weight value corresponding to the current iteration number, m1 is the initial iteration weight value, and b is a preset positive value.

[0026] In one possible implementation, determining the first update speed model based on the iteration weight value corresponding to the current iteration number, the adjustment speed values ​​corresponding to the multiple grid regions, and the initial speed model includes:

[0027] For multiple grid regions with corresponding adjustment speed values, the first update speed value corresponding to the grid region is calculated based on the following formula:

[0028]

[0029] Where i is the current iteration number, j is the index of the grid region, and the... It is the first update speed value corresponding to the j-th grid region, where m i It is the iteration weight value corresponding to the current iteration number, where v tj It is the adjustment speed value corresponding to the j-th grid region, where v 0j It is the initial velocity value corresponding to the j-th grid region;

[0030] For multiple grid regions for which no corresponding adjustment speed value has been determined, the initial speed value corresponding to the grid region is determined as the first update speed value corresponding to the grid region.

[0031] In one possible implementation, determining the first update speed model based on the iteration weight value corresponding to the current iteration number, the adjustment speed values ​​corresponding to the multiple grid regions, and the initial speed model includes:

[0032] Based on the prior information and prior weight values ​​of the aforementioned regions, the initial velocity model is locally adjusted to obtain the locally adjusted velocity model corresponding to the initial velocity model.

[0033] Based on the iteration weight value corresponding to the current iteration number and the adjustment speed value corresponding to the multiple grid regions, the local adjustment speed model is globally adjusted to obtain the first update speed model.

[0034] In one possible implementation, determining the velocity update difference corresponding to the first update velocity value of each target grid region based on the travel time of the plurality of first arrival waves, the propagation distance of each first arrival wave in the target grid regions it passes through, and the first update velocity value of each target grid region corresponding to the plurality of first arrival waves includes:

[0035] For each first arrival wave, a reference propagation time for the first arrival wave in each target grid region is determined based on the propagation distance of the first arrival wave in each target grid region it passes through and the first update rate value of each target grid region corresponding to the first arrival wave.

[0036] The sum of the reference propagation times of the first arrival wave in each target grid region it passes through is calculated as the total reference propagation time of the first arrival wave;

[0037] Based on the reference total propagation time of the first arrival wave and the travel time of the first arrival wave, the propagation time update difference of the first arrival wave in each target grid region it passes through is determined;

[0038] Based on the propagation time update difference of the first arrival wave in each target grid region it passes through and the propagation distance of the first arrival wave in each target grid region it passes through, the velocity update difference corresponding to the adjustment velocity value of each target grid region is determined.

[0039] Secondly, a velocity model determining apparatus is provided, the apparatus comprising:

[0040] A module is established to obtain the initial velocity model corresponding to the target area. The initial velocity model includes multiple data channels with different position coordinates. Each data channel includes at least one grid area corresponding to a different depth and an initial velocity value corresponding to each grid area.

[0041] The first determining module is used to determine the adjustment speed values ​​corresponding to multiple grid regions in the target region based on prior information of some regions in the target region and an interpolation algorithm;

[0042] The second determining module is used to determine the iteration weight value corresponding to the current iteration number based on the initial iteration weight value and the current iteration number, wherein the initial iteration weight value is the iteration weight value corresponding to the first iteration, and the iteration weight value corresponding to the current iteration number is negatively correlated with the current iteration number;

[0043] The third determining module is used to determine a first update speed model based on the iteration weight value corresponding to the current iteration number, the adjustment speed value corresponding to the multiple grid regions, and the initial speed model, wherein the first update speed model includes the first update speed value corresponding to the initial speed value of the multiple grid regions;

[0044] The acquisition module is used to acquire the travel times of multiple first arrival waves corresponding to the target area, wherein the travel times of the multiple first arrival waves are acquired through seismic data corresponding to the target area;

[0045] The fourth determining module is used to determine the propagation distance of each of the multiple first arrival waves in each target grid region it passes through, based on the ray tracing algorithm, the first update velocity model, and the source point coordinates and multiple receiver coordinates in the seismic data corresponding to the target region.

[0046] The fifth determining module is used to determine the velocity update difference corresponding to the first update velocity value of each target grid region based on the travel time of the multiple first arrival waves, the propagation distance of each first arrival wave in the target grid region it passes through, and the first update velocity value of each target grid region corresponding to the multiple first arrival waves.

[0047] The update module is used to update the first update speed model based on the speed update difference corresponding to the first update speed value of each target grid region to obtain a second update speed model, wherein the second update speed model includes the second update speed value corresponding to the first update speed value of the plurality of grid regions;

[0048] The judgment module is used to stop the iteration if the preset conditions are met and determine the second update speed model as the speed model, and to determine the second update speed model as the initial speed model if the preset conditions are not met.

[0049] In one possible implementation, the prior information of the partial region includes the layer information corresponding to each well logging in the partial region and the actual velocity value corresponding to each layer, wherein the layer information corresponding to the well logging includes the depth of at least one layer corresponding to the well logging.

[0050] The first determining module is used for:

[0051] Determine at least one logging grid area included in the data channel corresponding to each well log;

[0052] Based on the stratigraphic information corresponding to each well log and the depth corresponding to each well log grid area, the stratigraphic level to which each well log grid area belongs is determined;

[0053] For each logging grid area corresponding to each logging, the actual velocity value corresponding to the layer to which the logging grid area belongs is determined as the adjusted velocity value corresponding to the logging grid area;

[0054] Based on the adjustment velocity value corresponding to each logging grid area and the interpolation algorithm, the adjustment velocity values ​​corresponding to other grid areas in the target area besides the logging grid areas are determined.

[0055] In one possible implementation, the second determining module is configured to:

[0056] The iteration weight value corresponding to the current iteration number is calculated based on the following formula:

[0057] m i -m1=b*(i-1)

[0058] Where i is the current iteration number, and m i is the iteration weight value corresponding to the current iteration number, m1 is the initial iteration weight value, and b is a preset positive value.

[0059] In one possible implementation, the third determining module is configured to:

[0060] For multiple grid regions with corresponding adjustment speed values, the first update speed value corresponding to the grid region is calculated based on the following formula:

[0061]

[0062] Where i is the current iteration number, j is the index of the grid region, and the... It is the first update speed value corresponding to the j-th grid region, where m i It is the iteration weight value corresponding to the current iteration number, where v tj It is the adjustment speed value corresponding to the j-th grid region, where v 0j It is the initial velocity value corresponding to the j-th grid region;

[0063] For multiple grid regions for which no corresponding adjustment speed value has been determined, the initial speed value corresponding to the grid region is determined as the first update speed value corresponding to the grid region.

[0064] In one possible implementation, the third determining module is configured to:

[0065] Based on the prior information and prior weight values ​​of the aforementioned regions, the initial velocity model is locally adjusted to obtain the locally adjusted velocity model corresponding to the initial velocity model.

[0066] Based on the iteration weight value corresponding to the current iteration number and the adjustment speed value corresponding to the multiple grid regions, the local adjustment speed model is globally adjusted to obtain the first update speed model.

[0067] In one possible implementation, the fifth determining module is configured to:

[0068] For each first arrival wave, a reference propagation time for the first arrival wave in each target grid region is determined based on the propagation distance of the first arrival wave in each target grid region it passes through and the first update rate value of each target grid region corresponding to the first arrival wave.

[0069] The sum of the reference propagation times of the first arrival wave in each target grid region it passes through is calculated as the total reference propagation time of the first arrival wave;

[0070] Based on the reference total propagation time of the first arrival wave and the travel time of the first arrival wave, the propagation time update difference of the first arrival wave in each target grid region it passes through is determined;

[0071] Based on the propagation time update difference of the first arrival wave in each target grid region it passes through and the propagation distance of the first arrival wave in each target grid region it passes through, the velocity update difference corresponding to the adjustment velocity value of each target grid region is determined.

[0072] Thirdly, a computer device is provided, the computer device including a processor and a memory, the memory storing at least one instruction, the instruction being loaded and executed by the processor to implement the operation performed by the method for determining the speed model.

[0073] Fourthly, a computer-readable storage medium is provided, wherein at least one instruction is stored in the storage medium, the instruction being loaded and executed by a processor to implement the operation performed by the method for determining the speed model.

[0074] The beneficial effects of the technical solution provided in this application embodiment are as follows: The solution mentioned in this application embodiment can first determine the adjustment velocity values ​​corresponding to multiple grid regions in the target region based on prior information and interpolation algorithms for a portion of the region. Based on the iteration weight value corresponding to the current iteration number, the adjustment velocity values ​​corresponding to multiple grid regions, and the initial velocity value model, a first update velocity model is determined. Then, the travel times of multiple first arrival waves corresponding to the target region are obtained. Based on the ray tracing algorithm, the first update velocity model, and the source point coordinates and multiple receiver coordinates in the seismic data corresponding to the target region, the travel times of each first arrival wave in the first update velocity model are determined. The propagation distance in the target grid region is determined. Then, based on the travel time of the first arrival wave, the propagation distance of each first arrival wave in the target grid region it passes through, and the first update velocity value of each target grid region corresponding to these multiple first arrival waves, the adjustment velocity difference corresponding to the first update velocity value of each target grid region is determined. Then, the first update velocity model is updated based on the adjustment velocity difference to obtain the second update velocity model. At this point, it can be determined whether the current condition is met. If the preset condition is met, the obtained second update velocity model is determined as the velocity model. If the preset condition is not met, the obtained second update velocity model is determined as the initial velocity model, and the next iteration is performed. By using this application, since the initial velocity value in the initial velocity model is adjusted using prior information, a more accurate first update velocity model is obtained. Therefore, after each iteration update, a more accurate first update velocity model can be obtained, thus making the final velocity model more accurate. Attached Figure Description

[0075] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0076] Figure 1 This is a flowchart of a method for determining a velocity model provided in an embodiment of this application;

[0077] Figure 2 This is a flowchart of a method for determining a velocity model provided in an embodiment of this application;

[0078] Figure 3 This is a schematic diagram of a first data structure provided in an embodiment of this application;

[0079] Figure 4 This is a schematic diagram of a first data structure provided in an embodiment of this application;

[0080] Figure 5 This is a schematic diagram of a second data structure provided in an embodiment of this application;

[0081] Figure 6 This is a schematic diagram of a second data structure provided in an embodiment of this application;

[0082] Figure 7 This is a schematic diagram of a second data structure provided in an embodiment of this application;

[0083] Figure 8 This is a visualization of a velocity model provided in an embodiment of this application;

[0084] Figure 9 This is a radiation density effect diagram provided in an embodiment of this application;

[0085] Figure 10 This is a visualization of a velocity model provided in an embodiment of this application;

[0086] Figure 11 This is a radiation density effect diagram provided in an embodiment of this application;

[0087] Figure 12 This is a schematic diagram of the structure of a velocity model determination device provided in an embodiment of this application;

[0088] Figure 13 This is a structural block diagram of a server provided in an embodiment of this application. Detailed Implementation

[0089] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0090] This application provides a method for determining a speed model, which can be implemented by a server. The server can be a single server or a server cluster consisting of multiple servers.

[0091] A server may include a processor, memory, communication components, etc., with the processor connected to the memory and communication components respectively.

[0092] The processor can be a central processing unit (CPU). The processor can be used to read instructions and process data. For example, it can determine the adjustment speed value corresponding to multiple grid regions in the target area, determine the iteration weight value corresponding to the current iteration number, determine the first update speed model, determine the propagation distance of multiple first arrival waves, determine the speed update difference corresponding to the first update speed value of each target grid region, adjust the first update speed model based on the speed update difference corresponding to each target grid region to obtain the second update speed model, and determine whether the current preset conditions are met, etc.

[0093] The memory can be various types of volatile or non-volatile memory, such as solid-state drives (SSDs) and dynamic random access memory (DRAM). The memory can be used for data storage, for example, storing data of the acquired initial velocity model, data of prior information for a portion of the region, data corresponding to interpolation algorithms, data of adjusted velocity values ​​corresponding to multiple determined grid regions, data of initial iteration weights and the current iteration count, data of the determined first updated velocity model, data of seismic data corresponding to the target region, data of the travel times of multiple first-arrival waves corresponding to the acquired target region, data corresponding to ray tracing algorithms, data of the propagation distances of multiple determined first-arrival waves, data of the determined velocity update differences, data of the determined second updated velocity model, data of preset conditions, and so on.

[0094] Communication components can be wired network connectors, wireless fidelity (WiFi) modules, Bluetooth modules, cellular communication modules, etc. These components can be used to transmit data with other devices; for example, they can acquire seismic data corresponding to a target area or the travel times of multiple first-arrival waves corresponding to a target area from other devices.

[0095] This application provides a method for determining a velocity model, which includes the following steps 101-109, see below. Figure 1In the embodiments of this application, the following steps 101-109 can be used for multiple iterations. Each iteration processes steps 101-109 sequentially to obtain a more accurate velocity model. For example, after processing steps 101-109 in the first iteration, an updated velocity model is obtained. This updated velocity model can be redefined as the initial velocity model corresponding to the target region, and the second iteration is entered. Steps 101-109 are processed again, and so on, to complete the iterative process. The updated velocity model obtained in the last iteration is the finally determined, more accurate velocity model.

[0096] See below Figure 1 and Figure 2 The following describes the processing steps 101-109:

[0097] 101. Obtain the initial velocity model corresponding to the target area.

[0098] The target area is the actual work area, and its scope can be set according to actual needs. For example, it could be the area where City A is located, or a certain area within City A, etc. This application embodiment does not limit this. The initial velocity model includes multiple data channels with different position coordinates. Each data channel includes at least one grid region corresponding to a different depth and an initial velocity value corresponding to each grid region.

[0099] In implementation, a corresponding three-dimensional model can be established based on the actual range of the target area. Then, the three-dimensional model can be divided according to the size of the preset grid area, and the space of the three-dimensional model can be divided into multiple grid areas. An initial velocity value is assigned to each grid area, thus obtaining the initial velocity model corresponding to the target area.

[0100] The mesh region can be cuboid, thus dividing the space of the 3D model into multi-row, multi-column mesh regions. Each column of mesh regions is a data trace, and each data trace corresponds to a different position coordinate, which is the position coordinate in the horizontal direction. For a data trace, it includes at least one mesh region, and each of the mesh regions has a different depth, that is, different coordinates in the vertical direction.

[0101] In one possible implementation, the initial velocity value for each grid area can be set based on known geological or geophysical information (such as small refraction or micrologging information) or the experience of the staff in the target area. This application embodiment does not limit this.

[0102] In one possible implementation, the size and number of grid areas can be set according to the location, extent, and geological information of the target area, or they can be set according to requirements. This application embodiment does not limit this.

[0103] 102. Based on prior information and interpolation algorithms for some regions in the target area, determine the adjustment speed values ​​corresponding to multiple grid regions in the target area.

[0104] In practice, prior information about a portion of the target area can be obtained. This prior information can be any reasonable information, such as geological information, well logging information, or gravity, magnetic, electromagnetic, and seismic exploration information for that portion of the area, or other reasonable information. This application does not limit this information.

[0105] Based on prior information of a partial region, the actual velocity values ​​corresponding to multiple grid regions corresponding to the partial region are obtained. For these multiple grid regions corresponding to the partial region (i.e., the grid regions contained in the data channels whose position coordinates are located inside the partial region), the actual velocity value corresponding to each grid region can be directly determined as the adjustment velocity value corresponding to that grid region, thereby obtaining the adjustment velocity value of each grid region corresponding to the partial region.

[0106] Then, based on the adjustment speed values ​​and interpolation algorithms corresponding to these obtained grid regions, the adjustment speed values ​​corresponding to other grid regions, excluding some regions, can be determined.

[0107] The interpolation algorithm can be any reasonable algorithm, such as the Kriging method or the inverse distance multiplication method, etc., and the embodiments of this application do not limit it.

[0108] It is understandable that, for all remaining grid regions in all grid regions corresponding to the target region except for the grid regions corresponding to some regions, the adjustment speed value corresponding to all remaining grid regions can be determined by the adjustment speed value of the grid regions corresponding to some regions and the interpolation algorithm. For example, if the number of all grid regions corresponding to the target region is 100 and the number of grid regions corresponding to some regions is 30, then the number of all remaining grid regions is 70. The adjustment speed value corresponding to these 70 remaining grid regions can be calculated based on the adjustment speed value of the 30 grid regions corresponding to some regions and the interpolation algorithm.

[0109] Alternatively, based on the adjustment speed values ​​of the grid regions corresponding to a portion of the remaining grid regions and the interpolation algorithm, the adjustment speed values ​​can be determined only for a portion of the remaining grid regions.

[0110] In summary, based on prior information and interpolation algorithms for a portion of the region, the grid region for determining the corresponding adjustment speed value can be all grid regions corresponding to the target region, or it can be a portion of the grid regions. Staff can set this according to their needs, and this application embodiment does not limit this.

[0111] 103. Based on the initial iteration weight value and the current iteration number, determine the iteration weight value corresponding to the current iteration number.

[0112] The initial iteration weight value is the iteration weight value corresponding to the first iteration, and the iteration weight value corresponding to the current iteration number is negatively correlated with the current iteration number.

[0113] In practice, after determining the adjustment velocity values ​​corresponding to multiple grid regions, the initial velocity values ​​in the initial velocity model can be adjusted using the corresponding iterative weight values ​​and adjustment velocity values, thereby making them more accurate.

[0114] The iteration weight value corresponding to each iteration can be the same or different. In the embodiments of this application, the iteration weight value can change with the number of iterations. Specifically, the iteration weight value corresponding to the current iteration number is negatively correlated with the current iteration number, that is, as the number of iterations increases, the value of the iteration weight value decreases.

[0115] The significance of this setting is that, in this embodiment, the iteration weight value is the proportion of the adjustment speed value in the first update speed value. As the initial speed value is adjusted using the adjustment speed value in each iteration, the first update speed value obtained in each iteration becomes more and more accurate. In this case, as the number of iterations increases, the impact of the adjustment speed value on the accuracy of the first update speed value becomes smaller and smaller. Therefore, as the number of iterations increases, the corresponding iteration weight value can be reduced. In this way, a more suitable iteration weight value is used to match the adjustment speed value to adjust the initial speed value, making the obtained first update speed value more accurate.

[0116] 104. Based on the iteration weight value corresponding to the current iteration number, the adjustment speed value corresponding to multiple grid regions, and the initial speed model, determine the first update speed model.

[0117] The first update rate model includes the first update rate value corresponding to the initial rate value of multiple grid regions.

[0118] In implementation, after determining the iteration weight value corresponding to the current iteration number, the initial velocity values ​​corresponding to multiple grid regions in the initial velocity model can be adjusted by combining the iteration weight value corresponding to the current iteration number and the adjustment velocity values ​​corresponding to multiple grid regions. This adjusts the initial velocity values ​​corresponding to these multiple grid regions to the first update velocity values ​​corresponding to these multiple grid regions, thus obtaining the first update velocity model.

[0119] Understandably, the size and the mesh area contained in the first update velocity model are the same as those in the initial velocity model.

[0120] 105. Obtain the travel time of multiple first arrival waves corresponding to the target area.

[0121] The travel time of many first-arrival waves was obtained from the seismic data corresponding to the target area.

[0122] During implementation, staff can set up multiple shot points in the target area and install multiple geophones at multiple locations around each shot point. When a shot is fired, the resulting seismic waves propagate underground and are reflected back by the underlying layers, thus being received by the geophones around the shot point, allowing the acquisition of seismic data corresponding to the target area.

[0123] Staff can obtain the travel times of multiple first arrival waves corresponding to the target area from the earthquake data. The first arrival wave is the data of the first seismic wave received by the detector.

[0124] Understandably, it is only necessary to obtain the travel times of multiple first arrival waves corresponding to the target area from the seismic data of the target area during the first iteration. In the second iteration or subsequent iterations, it is only necessary to obtain the travel times of multiple first arrival waves obtained in the first iteration, without having to obtain them from the seismic data again.

[0125] 106. Based on the ray tracing algorithm, the first update velocity model, and the source point coordinates and multiple receiver coordinates in the seismic data corresponding to the target area, determine the propagation distance of each first arrival wave in each target grid area it passes through.

[0126] In practice, the position coordinates of the shot point and the geophones in the first update velocity model can be determined first by using the position coordinates of the shot point and the position coordinates of multiple geophones in the seismic data corresponding to the target area. Then, the position coordinates of the shot point and the geophones in the first update velocity model and the first update velocity model are input into the ray tracing algorithm to simulate the propagation path of each first arrival wave from the shot point to the corresponding geophone in the first update velocity model.

[0127] If the grid region through which the first arrival wave passes in the first update velocity model is determined as the target grid region, then the target grid region through which each first arrival wave passes in the first update velocity model can be determined by the determined propagation path of each first arrival wave, and thus the propagation distance of each first arrival wave in each target grid region can be determined.

[0128] 107. Based on the travel time of multiple first arrival waves, the propagation distance of each first arrival wave in the target grid area it passes through, and the first update velocity value of each target grid area corresponding to multiple first arrival waves, determine the velocity update difference corresponding to the first update velocity value of each target grid area.

[0129] In practice, the travel time of the first arrival wave is obtained based on the actual detected earthquake data, which is relatively accurate and consistent with the actual situation. Therefore, the travel time of the first arrival wave can be converted into data that can be compared with the first update velocity value. This data can then be compared with the first update velocity values ​​corresponding to multiple target grid areas in the first update velocity model to determine the velocity update difference corresponding to the first update velocity values ​​of these multiple target grid areas. The velocity update difference is the adjustment value of the first update velocity value.

[0130] 108. Based on the speed update difference corresponding to the first update speed value of each target grid region, update the first update speed model to obtain the second update speed model.

[0131] The second update rate model includes the second update rate value corresponding to the first update rate value of multiple grid regions.

[0132] In practice, after determining the velocity update difference corresponding to multiple target grid regions, the velocity update difference can be used to adjust and update the first update velocity value corresponding to the target grid region, thereby obtaining the second update velocity model.

[0133] Understandably, the size and included mesh regions of the second update rate model are the same as those of the first update rate model. For all mesh regions included in the first update rate model, it is divided into multiple target mesh regions and other remaining mesh regions. For the multiple target mesh regions, their corresponding first update rate values ​​are adjusted and updated using their corresponding rate update differences to obtain the second update rate value corresponding to the target mesh region. For the remaining mesh regions, their corresponding first update rate values ​​can be directly determined as their corresponding second update rate values.

[0134] In one possible implementation, to improve the accuracy of the second update velocity model, multiple shot points can be uniformly set in the target area when acquiring seismic data. This allows the propagation path of the first arrival wave determined based on the seismic data corresponding to these multiple shot points to pass through each grid area corresponding to the target area, thereby obtaining the velocity update difference corresponding to each grid area, and adjusting and updating each grid area.

[0135] 109. If the preset conditions are met, the iteration stops and the second update speed model is determined as the speed model. If the preset conditions are not met, the second update speed model is determined as the initial speed model.

[0136] During implementation, staff can set preset conditions. Once the second update speed model is determined, it can be determined whether the preset conditions are met. If they are met, there is no need to perform the next iteration. The currently determined second update speed model can be directly determined as the final speed model. If the preset conditions are not met, the next iteration is required. The currently determined second update speed model is determined as the initial speed model, and steps 101-109 are performed again.

[0137] In implementation, the preset conditions can be any reasonable conditions. For example, it can be the target number of iterations. When the number of iterations reaches the target number of iterations, the second update speed model of the target number of iterations is determined as the final speed model. Of course, it can also be other preset conditions. This application embodiment does not limit this.

[0138] The following section provides a more detailed explanation of step 102, using prior information as well logging information as an example:

[0139] When the prior information is well logging information, the prior information for a certain area may include the layer information corresponding to each well logging in the certain area and the actual velocity value corresponding to each layer. The layer information corresponding to the well logging includes the depth (or thickness) of at least one layer corresponding to the well logging. For example, the depth of the first layer is 20m, the depth of the second layer is 40m, the depth of the third layer is 80m, and so on.

[0140] Based on the prior information obtained from the aforementioned partial regions, the following processing can be performed when determining the adjustment velocity values ​​corresponding to multiple grid regions in the target region:

[0141] Each well logging data channel is identified as including at least one logging grid region. Based on the stratigraphic information and depth of each logging grid region, the stratigraphic level to which each logging grid region belongs is determined. For each logging grid region corresponding to each well logging, the actual velocity value corresponding to the stratigraphic level to which the logging grid region belongs is determined as the adjusted velocity value corresponding to the logging grid region. Based on the adjusted velocity value and interpolation algorithm of each logging grid region, the adjusted velocity values ​​corresponding to other grid regions in the target area besides the logging grid regions are determined.

[0142] In practice, each well log can correspond to a data channel. Based on the location of the well log in the target area and the location coordinates of each data channel in the initial velocity model, the data channel corresponding to each well log is determined, and at least one grid area contained in the data channel corresponding to the well log is defined as the well log grid area.

[0143] For each well log, based on the stratigraphic information corresponding to the well log, the depth of each stratigraphic layer, and the depth of at least one well log grid area corresponding to the well log, the stratigraphic layer to which each well log grid area belongs is determined. For example, when the stratigraphic information corresponding to well A includes three stratigraphic layers, the depth of the first stratigraphic layer is 0-15m, the depth of the second stratigraphic layer is 15m-40m, and the depth of the third stratigraphic layer is 40m-120m, if the depth of the well log grid area is 26m, then the well log grid area belongs to the second stratigraphic layer.

[0144] After determining the layer to which each logging grid area belongs by each logging operation using the above method, the actual velocity value corresponding to that layer in the prior information can be assigned to the corresponding logging grid area, thereby obtaining the actual velocity value corresponding to each logging grid area, which is then determined as the adjustment velocity value corresponding to the logging grid area.

[0145] For all grid regions included in the initial velocity model, besides the well logging grid region, there are other grid regions. In this case, there are three processing methods:

[0146] The first method involves using interpolation algorithms and the stratigraphic information corresponding to each well logging in a certain area to determine the stratigraphic information corresponding to other data channels besides the well logging data channels. Then, based on the stratigraphic information corresponding to the other data channels, the stratigraphic level of each grid area included in it is determined, and the actual velocity value corresponding to that stratigraphic level is determined as the adjusted velocity value corresponding to that grid area.

[0147] The second method is to determine the adjustment rate value for grid areas other than the well logging grid area by using an interpolation algorithm and the adjustment rate value corresponding to the well logging grid area.

[0148] The third method is to combine the first and second methods. If there are still grid areas where the corresponding adjustment speed value cannot be determined after using the first method, the second method can be used to determine it.

[0149] It is understood that the other grid regions for determining the corresponding adjustment velocity value can be all remaining grid regions other than the well logging grid region in all grid regions included in the initial velocity model, or it can be a portion of the grid regions in all remaining grid regions. The number and range of other grid regions can be set according to actual needs, and this application embodiment does not limit this.

[0150] The following is a more detailed explanation of step 103:

[0151] In this embodiment, the iteration weight value corresponding to the current iteration number is negatively correlated with the current iteration number. That is, as the current iteration number increases, the corresponding iteration weight value gradually decreases, thereby gradually reducing the influence of the adjustment speed value on the initial speed value.

[0152] Furthermore, the iteration weight value corresponding to the current iteration number can be inversely proportional to the current iteration number. In one possible implementation, the iteration weight value corresponding to the current iteration number can be calculated based on the following formula (1):

[0153] m i -m1=b*(i-1) (1)

[0154] Where i is the current iteration number, m i is the iteration weight value corresponding to the current iteration number, m1 is the initial iteration weight value, and b is a preset positive value.

[0155] For example, if the initial iteration weight is 0.9 and b is 0.1, then the iteration weight for the second iteration is 0.8, the iteration weight for the third iteration is 0.7, the iteration weight for the fourth iteration is 0.6, and so on.

[0156] The following is a more detailed explanation of step 104:

[0157] In this application embodiment, there are multiple ways to determine the first update speed model, two of which are as follows:

[0158] The first type

[0159] In implementation, the iteration weight value corresponding to the current iteration number and the adjustment velocity values ​​corresponding to multiple grid regions can be used to adjust and update the initial velocity values ​​corresponding to these multiple grid regions in the initial velocity model, thereby obtaining the first updated velocity value corresponding to these multiple grid regions, i.e., obtaining the first updated velocity model. It can be understood that when calculating the first updated velocity value, for each grid region among the multiple grid regions with an adjustment velocity value, the adjustment velocity value corresponding to that grid region can be used to adjust and update the initial velocity value corresponding to that grid region, thereby obtaining the first updated velocity value corresponding to that grid region. For each grid region among the multiple grid regions without an adjustment velocity value, the initial velocity value corresponding to that grid region can be directly determined as the first updated velocity value corresponding to that grid region.

[0160] In one possible implementation, the first update rate model can be determined based on the following method:

[0161] 1. For multiple grid regions with corresponding adjustment rate values, the first update rate value corresponding to the grid region can be calculated based on the following formula (2):

[0162]

[0163] Where i is the current iteration number, and j is the index of the grid region. It is the first update speed value corresponding to the j-th grid region, m i It is the iteration weight value corresponding to the current iteration number, v tj It is the adjustment speed value corresponding to the j-th grid region, v 0j It is the initial velocity value corresponding to the j-th grid region.

[0164] For example, if the initial velocity value corresponding to the grid region is 5 km / s, the adjustment velocity value corresponding to the grid region is 5.6 km / s, and the iteration weight value corresponding to the current iteration number is 0.8, then the first update velocity value corresponding to the grid region is 0.8*5.6+(1-0.8)*5=5.48.

[0165] 2. For multiple grid regions for which the corresponding adjustment speed value has not been determined, the initial speed value corresponding to the grid region is determined as the first update speed value corresponding to the grid region.

[0166] The second type

[0167] Before adjusting the initial velocity values ​​in the initial velocity model using the adjusted velocity values, prior information can be used to locally adjust the initial velocity values ​​in the initial velocity model. This involves first using relatively accurate prior information to perform a more precise adjustment and update of a portion of the initial velocity model, and then using the calculated adjusted velocity values ​​corresponding to multiple grid regions to perform a comprehensive adjustment and update of the initial velocity model, resulting in a more accurate first updated velocity model. The corresponding processing can be as follows:

[0168] Based on prior information and prior weight values ​​of some regions, the initial velocity model is locally adjusted to obtain the locally adjusted velocity model corresponding to the initial velocity model; based on the iteration weight value corresponding to the current iteration number and the adjustment velocity values ​​corresponding to multiple grid regions, the locally adjusted velocity model is globally adjusted to obtain the first update velocity model.

[0169] For local adjustments: In implementation, in step 102 above, the actual velocity values ​​(or adjusted velocity values) corresponding to multiple grid regions corresponding to the partial region are obtained from the prior information of the partial region. In the multiple grid regions included in the initial velocity model, for each grid region corresponding to the partial region, the actual velocity value and prior weight value corresponding to the grid region are used to adjust and update the initial velocity value corresponding to the grid region, thereby obtaining the local adjusted velocity value corresponding to the grid region. For each other grid region in the initial velocity model other than the grid region corresponding to the partial region, the initial velocity value corresponding to the grid region can be directly determined as the local adjusted velocity value corresponding to the grid region, thereby obtaining the local adjusted velocity model. The local adjusted velocity model includes the local adjusted velocity values ​​corresponding to the initial velocity values ​​of multiple grid regions.

[0170] In one possible implementation, the local adjustment velocity model can be determined based on the following method:

[0171] 1. For multiple grid regions corresponding to a certain area, the local adjustment velocity value corresponding to the grid region can be calculated based on the following formula (3):

[0172]

[0173] Where i is the current iteration number, and j is the index of the grid region. v is the local adjustment velocity value corresponding to the j-th grid region, n is the prior weight value, and v uj It is the actual velocity value corresponding to the j-th grid region, v 0j It is the initial velocity value corresponding to the j-th grid region.

[0174] 2. For grid regions other than the grid regions corresponding to certain areas, the initial velocity value corresponding to the grid region is determined as the local adjustment velocity value corresponding to that grid region.

[0175] For global adjustment: After obtaining the local adjustment speed model through the above processing method, the local adjustment speed model can be globally adjusted based on the iteration weight value corresponding to the current iteration number and the adjustment speed value corresponding to multiple grid regions, thereby obtaining the first update speed model.

[0176] In one possible implementation, the first update rate model can be determined based on the following method:

[0177] 1. For multiple grid regions with corresponding adjustment speed values, the first update speed value corresponding to the grid region can be calculated based on the following formula (4):

[0178]

[0179] Where i is the current iteration number, and j is the index of the grid region. It is the first update speed value corresponding to the j-th grid region, m i It is the iteration weight value corresponding to the current iteration number, v tj It is the adjustment speed value corresponding to the j-th grid region. It is the local adjustment speed value corresponding to the j-th grid region.

[0180] 2. For multiple grid regions for which the corresponding adjustment speed value has not been determined, the initial speed value corresponding to the grid region is determined as the first update speed value corresponding to the grid region.

[0181] The following is a more detailed explanation of step 107:

[0182] In this embodiment of the application, the method for determining the velocity update difference corresponding to the first update velocity value of each target grid region can be as follows:

[0183] For each first-arrival wave, based on the propagation distance of the first-arrival wave in each target grid region it passes through and the first update velocity value of each target grid region corresponding to the first-arrival wave, the reference propagation time of the first-arrival wave in each target grid region it passes through is determined. The sum of the reference propagation times of the first-arrival wave in each target grid region it passes through is calculated as the total reference propagation time of the first-arrival wave. Based on the total reference propagation time of the first-arrival wave and the travel time of the first-arrival wave, the propagation time update difference of the first-arrival wave in each target grid region it passes through is determined. Based on the propagation time update difference of the first-arrival wave in each target grid region it passes through and the propagation distance of the first-arrival wave in each target grid region it passes through, the velocity update difference corresponding to the adjustment velocity value of each target grid region is determined.

[0184] In implementation, each first arrival wave is processed as follows:

[0185] For each target grid region corresponding to the first arrival wave, the ratio between the propagation distance of the first arrival wave in that target grid region and the first update velocity value corresponding to that target grid region is determined as the reference propagation time of the first arrival wave in that target grid region. This yields the reference propagation time of the first arrival wave in each target grid region it passes through. The sum of the reference propagation times of the first arrival wave in each target grid region it passes through is the total reference propagation time of the first arrival wave.

[0186] The total reference propagation time calculated above is based on the established first update velocity model. It is compared with the actual travel time of the first arrival wave obtained from seismic data to determine whether the first update velocity value in the first update velocity model is accurate. The corresponding processing can be as follows: The difference between the total reference propagation time of the first arrival wave and the travel time of the first arrival wave is determined as the total propagation time difference of the first arrival wave. Then, for each target grid area corresponding to the first arrival wave, the propagation distance of the first arrival wave in the target grid area can be calculated as the proportion of the propagation distance of the first arrival wave in the sum of the propagation distances of the first arrival wave in all target grid areas. Then, the total propagation time difference of the first arrival wave is multiplied by the proportion corresponding to each target grid area to obtain the propagation time update difference of the first arrival wave in each target grid area. The propagation time update difference of the first arrival wave in each target grid area can be calculated based on the following formula (5):

[0187]

[0188] Where k is the index of the target grid region, Δt k It is the difference in propagation time of the first arrival wave in the k-th target grid region, d k Δd is the propagation distance of the first arrival wave in the k-th target grid region, D is the sum of the propagation distances of the first arrival wave in all target grid regions, and Δd is the total difference in propagation time corresponding to the first arrival wave.

[0189] After calculating the propagation time update difference of each first arrival wave in each target grid region using the above formula (5), for each target grid region corresponding to each first arrival wave, the ratio of the propagation distance of the first arrival wave in the target grid region to the propagation time update difference of the first arrival wave in the target grid region is determined as the speed update difference corresponding to the adjustment speed value of the target grid region.

[0190] Correspondingly, after obtaining the velocity update difference corresponding to each target grid region, the first update velocity model can be updated based on the velocity update difference to obtain the second update model. The corresponding process can be: for each target grid region, add the velocity update difference corresponding to the target grid region to the first update velocity value corresponding to the target grid region to obtain the second update velocity value corresponding to the target region.

[0191] In one possible implementation, this application embodiment also provides a first data structure, which can be established as follows when adjusting the initial velocity model based on the iteration weight value or prior weight value corresponding to the current iteration number: Figure 3 The first data structure shown.

[0192] The first data structure consists of four units. From left to right, the first unit (r) represents the index number corresponding to the data track in the initial velocity model, the second unit (J) represents the index number of the data track in the initial velocity model, and the third unit (J) represents the index number of the data track in the initial velocity model. r The first cell represents the number of grid regions included in the data channel, and the second cell represents the iteration weight value (m) corresponding to the current iteration number. r ) or the prior weight value (n) corresponding to that data channel. r The fourth cell represents the initial velocity value of the multiple grid regions included in the data channel. Or adjust the speed value locally.

[0193] For example, if the 0th data channel includes 3 grid regions, when adjusting the initial velocity values ​​corresponding to the 3 grid regions based on the iteration weight value corresponding to the current iteration number, a system can be established as follows: Figure 4 The first data structure shown is from Figure 4 As can be seen, the index number of this data channel is 0, and it includes 3 grid regions. The initial velocity values ​​corresponding to these three grid regions are 459.7, 486.5, and 550.8, respectively, and the iteration weight value corresponding to the current iteration number is 0.8.

[0194] In the first data structure described above, the meanings represented by the third and fourth units can be divided into two cases:

[0195] The first type: the third cell represents the prior weight value, and the fourth cell represents the initial velocity value of the multiple grid regions included in the data channel.

[0196] The second approach: The third cell represents the iteration weight value corresponding to the current iteration number, and the fourth cell represents the initial velocity value or the locally adjusted velocity value of the multiple grid regions included in the data trace. In other words, when the initial velocity value is adjusted using the iteration weight value without prior weight values ​​for local adjustment, the fourth cell represents the initial velocity value of the multiple grid regions included in the data trace. Conversely, when the initial velocity value is locally adjusted using prior weight values ​​before adjusting the initial velocity value using the iteration weight value, the fourth cell represents the locally adjusted velocity value of the multiple grid regions included in the data trace.

[0197] The index number of the data channel recorded in the first unit above can be pre-set for each data channel included in the initial velocity model. The index number can start from 0. For example, as shown in the first data structure above, the data channel with index number 0 is the first data channel in the initial velocity model. Of course, the index number can also be set arbitrarily and reasonably according to actual needs, and this application embodiment does not limit it.

[0198] In the prior art, when adjusting matrix data (data in matrix form) using weights, it is necessary to generate weight data corresponding to the matrix data. This weight data also has a matrix form, and its number of rows, columns, and elements corresponds to the matrix data.

[0199] In the embodiments of this application, when adjusting the initial velocity value in the initial velocity model, the following method is used: Figure 3 The first data structure shown here, by establishing a corresponding first data structure for each data channel, makes the data more intuitive and makes it more convenient for staff to view the data.

[0200] Furthermore, staff can modify the iterative weight value or prior weight value corresponding to any data channel according to the actual situation or corresponding needs. That is, they can modify the third unit in the first data structure corresponding to different data channels to obtain the iterative weight value or prior weight value corresponding to the data channel recorded in the first unit of the first data structure, thereby improving the flexibility of operation.

[0201] Based on the first data structure, embodiments of this application provide a second data structure, which further includes the layer corresponding to each data channel, i.e., as shown below. Figure 5 As shown, the second data structure includes at least seven units. From left to right, the first unit (r) represents the index number corresponding to the data track in the initial velocity model, and the second unit (J) represents the index number corresponding to the data track in the initial velocity model. r The third cell (C) represents the number of grid regions included in the data channel. r The first element (a1) represents the number of layers included in the data channel, the second element (a1) represents the index number corresponding to the first layer included in the data channel, and the third element (a1) represents the index number corresponding to the first layer included in the data channel. The sixth cell represents the number of grid regions included in the layer recorded in the fourth cell of this data channel, and the sixth cell represents the iteration weight value corresponding to the layer recorded in the fourth cell of this data channel. Or prior weight values The seventh cell represents the initial velocity value of at least one grid region included in the layer recorded in the fourth cell of this data channel. Or adjust the speed value locally.

[0202] When the number of layers recorded in the third unit is 1, it indicates that the data channel includes only one layer. In this case, the second data structure corresponding to the data channel includes seven units, for example, as shown below. Figure 6 As shown, the 8th data channel includes only one layer, and this layer includes 2 grid areas.

[0203] When the number of layers recorded in the third unit is greater than 1, it indicates that the data channel includes multiple layers. In this case, the second data structure corresponding to the data channel not only includes seven units, but also includes an eighth unit, a ninth unit, or even more units after the seventh unit. Among them, the eighth unit (a2) represents the index number corresponding to the second layer included in the data channel, and the ninth unit... The tenth cell represents the number of grid regions included in the layer recorded in the eighth cell of this data channel, and the tenth cell represents the iteration weight value corresponding to the layer recorded in the eighth cell of this data channel. Or prior weight values The eleventh cell represents the initial velocity value of at least one grid region included in the layer recorded in the eighth cell of this data channel. Or adjust the speed value locally. The twelfth unit represents the index number corresponding to the third layer included in this data channel, and so on. The second data structure corresponding to this data channel can include all layers included in this data channel, the index number corresponding to each layer, the number of grid regions included in each layer, the iterative weight value or prior weight value corresponding to each layer, and the initial velocity value or local adjustment value of the grid regions included in each layer. For example, Figure 7 As shown, the 12th data channel includes 2 layers, each of which includes 3 grid regions. The prior weight value of the first layer (the index number of the layer is 0) is 0.8, and the prior weight value of the second layer (the index number of the layer is 1) is 0.82.

[0204] In the second data structure described above, the meanings represented by the sixth and seventh units can also be divided into two cases:

[0205] The first type: the sixth cell represents the prior weight value corresponding to the layer recorded in the fourth cell of the data channel, and the seventh cell represents the initial velocity value corresponding to at least one grid region included in the layer recorded in the fourth cell of the data channel.

[0206] The second approach: The sixth cell represents the iterative weight value corresponding to the layer recorded in the fourth cell of the data channel, and the seventh cell represents the initial velocity value or locally adjusted velocity value of at least one grid region included in the layer recorded in the fourth cell of the data channel. It can be understood that when the initial velocity value is adjusted using the iterative weight value, and no prior weight value is used for local adjustment of the initial velocity value, the seventh cell represents the initial velocity value of at least one grid region included in the layer recorded in the fourth cell of the data channel. Conversely, when the initial velocity value is locally adjusted using a prior weight value before adjusting iterative weight values, the seventh cell represents the locally adjusted velocity value of at least one grid region included in the layer recorded in the fourth cell of the data channel.

[0207] Similarly, the meanings represented by the tenth and eleventh units can also be divided in the same way as described above, and will not be repeated here.

[0208] Using this second data structure, a corresponding second data structure is established for each data channel. In the second data structure, the data channel is further divided by layer, which makes the data more intuitive and improves the convenience for staff to view the data.

[0209] Furthermore, staff can modify the iterative weight value or prior weight value corresponding to any layer in any data channel according to the actual situation or corresponding needs. That is, they can modify the values ​​in the sixth, tenth, fourteenth, etc. units of the second data structure corresponding to different data channels, thereby obtaining the iterative weight value or prior weight value corresponding to different layers in different data channels, which improves the flexibility of operation.

[0210] The following sections will introduce the visualization results of the velocity model obtained without adjusting for iterative and prior weight values, and the visualization results of the velocity model obtained after adjusting for iterative and prior weight values:

[0211] like Figure 8-11 As shown, Figure 8 This is a visualization of the velocity model obtained without adjusting for iterative and prior weight values. Figure 9 for Figure 8 The image shows the ray density effect corresponding to the velocity model. Figure 10 This is a visualization of the velocity model obtained after adjustments using iterative and prior weight values. Figure 11 for Figure 10 The image shows the ray density effect corresponding to the velocity model.

[0212] It can be seen that, Figure 8The velocity model shown contains many light-colored gaps within the dark areas. This means that the velocity values ​​corresponding to the light-colored gaps are inaccurate, resulting in a discontinuous velocity model. Figure 10 In the velocity model shown, the dark areas are relatively continuous, and the light-colored areas have fewer breaks, i.e. Figure 10 The velocity model shown is more accurate.

[0213] Similarly, in Figure 9 In the ray density diagram shown, it can be seen that the dark areas are somewhat discontinuous, with lighter-colored gaps between them. Figure 11 In the ray density rendering shown, the dark areas are relatively continuous, indicating that the velocity model is quite accurate. Workers can then... Figure 10 and Figure 11 More comprehensive and accurate information can be found in the corresponding speed model.

[0214] In summary, adjusting the initial velocity model using prior weights and then adjusting the locally adjusted velocity model using iterative weights can effectively improve the accuracy of the final determined velocity model.

[0215] All of the above-mentioned optional technical solutions can be combined in any way to form the optional embodiments of this application, and will not be described in detail here.

[0216] The scheme mentioned in this application embodiment can first determine the adjusted velocity values ​​corresponding to multiple grid regions in the target region based on prior information and interpolation algorithms for a portion of the region. Then, based on the iteration weight value corresponding to the current iteration number, the adjusted velocity values ​​corresponding to multiple grid regions, and the initial velocity value model, a first update velocity model is determined. Next, the travel times of multiple first-arrival waves corresponding to the target region are obtained. Finally, based on the ray tracing algorithm, the first update velocity model, and the source coordinates and multiple receiver coordinates in the seismic data corresponding to the target region, the propagation distance of each first-arrival wave in the target grid region traversed in the first update velocity model is determined. Then, based on the travel time of the first arrival wave, the propagation distance of each first arrival wave in the target grid region it passes through, and the first update velocity value of each target grid region corresponding to these multiple first arrival waves, the adjustment velocity difference corresponding to the first update velocity value of each target grid region is determined. Then, the first update velocity model is updated based on the adjustment velocity difference to obtain the second update velocity model. At this point, it can be determined whether the preset conditions are met. If the preset conditions are met, the obtained second update velocity model is determined as the velocity model; if the preset conditions are not met, the obtained second update velocity model is determined as the initial velocity model, and the next iteration is performed. Using this application, because the initial velocity value in the initial velocity model is adjusted using prior information, a more accurate first update velocity model is obtained. Therefore, after each iteration update, a more accurate first update velocity model can be obtained, thus making the final velocity model more accurate.

[0217] This application provides a device for determining a velocity model. This device can be the computer equipment described in the above embodiments, such as... Figure 12 As shown, the device includes:

[0218] A module 1210 is established to obtain an initial velocity model corresponding to the target area. The initial velocity model includes multiple data channels with different position coordinates. Each data channel includes at least one grid area corresponding to a different depth and an initial velocity value corresponding to each grid area.

[0219] The first determining module 1220 is used to determine the adjustment speed value corresponding to multiple grid regions in the target region based on prior information of some regions in the target region and an interpolation algorithm;

[0220] The second determining module 1230 is used to determine the iteration weight value corresponding to the current iteration number based on the initial iteration weight value and the current iteration number, wherein the initial iteration weight value is the iteration weight value corresponding to the first iteration, and the iteration weight value corresponding to the current iteration number is negatively correlated with the current iteration number;

[0221] The third determining module 1240 is used to determine a first update speed model based on the iteration weight value corresponding to the current iteration number, the adjustment speed value corresponding to the multiple grid regions, and the initial speed model, wherein the first update speed model includes the first update speed value corresponding to the initial speed value of the multiple grid regions;

[0222] The acquisition module 1250 is used to acquire the travel times of multiple first arrival waves corresponding to the target area, wherein the travel times of the multiple first arrival waves are acquired through seismic data corresponding to the target area;

[0223] The fourth determining module 1260 is used to determine the propagation distance of each of the multiple first arrival waves in each target grid region it passes through, based on the ray tracing algorithm, the first update velocity model, and the source point coordinates and multiple receiver coordinates in the seismic data corresponding to the target region.

[0224] The fifth determining module 1270 is used to determine the velocity update difference corresponding to the first update velocity value of each target grid region based on the travel time of the multiple first arrival waves, the propagation distance of each first arrival wave in the target grid region it passes through, and the first update velocity value of each target grid region corresponding to the multiple first arrival waves.

[0225] The update module 1280 is used to update the first update speed model based on the speed update difference corresponding to the first update speed value of each target grid region to obtain a second update speed model, wherein the second update speed model includes the second update speed value corresponding to the first update speed value of the plurality of grid regions;

[0226] The judgment module 1290 is used to stop the iteration if the preset conditions are met and determine the second update speed model as the speed model, and to determine the second update speed model as the initial speed model if the preset conditions are not met.

[0227] In one possible implementation, the prior information of the partial region includes the layer information corresponding to each well logging in the partial region and the actual velocity value corresponding to each layer, wherein the layer information corresponding to the well logging includes the depth of at least one layer corresponding to the well logging.

[0228] The first determining module 1220 is used for:

[0229] Determine at least one logging grid area included in the data channel corresponding to each well log;

[0230] Based on the stratigraphic information corresponding to each well log and the depth corresponding to each well log grid area, the stratigraphic level to which each well log grid area belongs is determined;

[0231] For each logging grid area corresponding to each logging, the actual velocity value corresponding to the layer to which the logging grid area belongs is determined as the adjusted velocity value corresponding to the logging grid area;

[0232] Based on the adjustment velocity value corresponding to each logging grid area and the interpolation algorithm, the adjustment velocity values ​​corresponding to other grid areas in the target area besides the logging grid areas are determined.

[0233] In one possible implementation, the second determining module 1230 is configured to:

[0234] The iteration weight value corresponding to the current iteration number is calculated based on the following formula:

[0235] m i -m1=b*(i-1)

[0236] Where i is the current iteration number, and m i is the iteration weight value corresponding to the current iteration number, m1 is the initial iteration weight value, and b is a preset positive value.

[0237] In one possible implementation, the third determining module 1240 is configured to:

[0238] For multiple grid regions with corresponding adjustment speed values, the first update speed value corresponding to the grid region is calculated based on the following formula:

[0239]

[0240] Where i is the current iteration number, j is the index of the grid region, and the... It is the first update speed value corresponding to the j-th grid region, where m i It is the iteration weight value corresponding to the current iteration number, where v tj It is the adjustment speed value corresponding to the j-th grid region, where v 0j It is the initial velocity value corresponding to the j-th grid region;

[0241] For multiple grid regions for which no corresponding adjustment speed value has been determined, the initial speed value corresponding to the grid region is determined as the first update speed value corresponding to the grid region.

[0242] In one possible implementation, the third determining module 1240 is configured to:

[0243] Based on the prior information and prior weight values ​​of the aforementioned regions, the initial velocity model is locally adjusted to obtain the locally adjusted velocity model corresponding to the initial velocity model.

[0244] Based on the iteration weight value corresponding to the current iteration number and the adjustment speed value corresponding to the multiple grid regions, the local adjustment speed model is globally adjusted to obtain the first update speed model.

[0245] In one possible implementation, the fifth determining module 1270 is configured to:

[0246] For each first arrival wave, a reference propagation time for the first arrival wave in each target grid region is determined based on the propagation distance of the first arrival wave in each target grid region it passes through and the first update rate value of each target grid region corresponding to the first arrival wave.

[0247] The sum of the reference propagation times of the first arrival wave in each target grid region it passes through is calculated as the total reference propagation time of the first arrival wave;

[0248] Based on the reference total propagation time of the first arrival wave and the travel time of the first arrival wave, the propagation time update difference of the first arrival wave in each target grid region it passes through is determined;

[0249] Based on the propagation time update difference of the first arrival wave in each target grid region it passes through and the propagation distance of the first arrival wave in each target grid region it passes through, the velocity update difference corresponding to the adjustment velocity value of each target grid region is determined.

[0250] It should be noted that the speed model determination device provided in the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the speed model determination device and the speed model determination method embodiments provided in the above embodiments belong to the same concept, and their specific implementation process can be found in the method embodiments, which will not be repeated here.

[0251] Figure 13This is a schematic diagram of a server structure provided in an embodiment of this application. The server 1300 can vary significantly due to different configurations or performance. It may include one or more central processing units (CPUs) 1301 and one or more memories 1302. The memories 1302 store at least one instruction, which is loaded and executed by the processor 1301 to implement the methods provided in the various method embodiments described above. Of course, the server may also have wired or wireless network interfaces, a keyboard, and input / output interfaces for input and output. The server may also include other components for implementing device functions, which will not be elaborated upon here.

[0252] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including instructions that can be executed by a processor in a terminal to complete the speed model determination method in the above embodiments. The computer-readable storage medium may be non-transitory. For example, the computer-readable storage medium may be ROM (read-only memory), RAM (random access memory), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

[0253] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0254] It should be noted that all information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.), and signals (including but not limited to signals transmitted between user terminals and other devices) involved in this application have been authorized by the user or fully authorized by all parties, and the collection, use, and processing of related data must comply with the relevant laws, regulations, and standards of the relevant countries and regions. For example, the "prior information of some areas" and "seismic data corresponding to the target area" involved in this application were obtained with full authorization.

[0255] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for determining a velocity model, characterized in that, The method includes: Obtain the initial velocity model corresponding to the target area, wherein the initial velocity model includes multiple data channels with different position coordinates, and each data channel includes at least one grid region corresponding to a different depth and an initial velocity value corresponding to each grid region; Based on prior information and interpolation algorithms for some regions within the target region, the adjustment speed values ​​corresponding to multiple grid regions within the target region are determined; Based on the initial iteration weight value and the current iteration number, the iteration weight value corresponding to the current iteration number is determined, wherein the initial iteration weight value is the iteration weight value corresponding to the first iteration, and the iteration weight value corresponding to the current iteration number is negatively correlated with the current iteration number; Based on the iteration weight value corresponding to the current iteration number, the adjustment speed value corresponding to the multiple grid regions, and the initial speed model, a first update speed model is determined, wherein the first update speed model includes the first update speed value corresponding to the initial speed value of the multiple grid regions; The travel times of multiple first arrival waves corresponding to the target area are obtained, wherein the travel times of the multiple first arrival waves are obtained through seismic data corresponding to the target area; Based on the ray tracing algorithm, the first update velocity model, and the source point coordinates and multiple receiver coordinates in the seismic data corresponding to the target area, the propagation distance of each first arrival wave in each target grid area is determined. Based on the travel time of the multiple first arrival waves, the propagation distance of each first arrival wave in the target grid region it passes through, and the first update rate value of each target grid region corresponding to the multiple first arrival waves, the speed update difference corresponding to the first update rate value of each target grid region is determined. Based on the speed update difference corresponding to the first update speed value of each target grid region, the first update speed model is updated to obtain a second update speed model, wherein the second update speed model includes the second update speed value corresponding to the first update speed value of the plurality of grid regions; If the preset conditions are met, the iteration stops and the second update speed model is determined as the speed model. If the preset conditions are not met, the second update speed model is determined as the initial speed model.

2. The method according to claim 1, characterized in that, The prior information of the partial area includes the layer information corresponding to each well logging in the partial area and the actual velocity value corresponding to each layer, wherein the layer information corresponding to the well logging includes the depth of at least one layer corresponding to the well logging; The step of determining the adjustment speed values ​​corresponding to multiple grid regions in the target region based on prior information and interpolation algorithms of a portion of the target region includes: Determine at least one logging grid area included in the data channel corresponding to each well log; Based on the stratigraphic information corresponding to each well log and the depth corresponding to each well log grid area, the stratigraphic level to which each well log grid area belongs is determined; For each logging grid area corresponding to each logging, the actual velocity value corresponding to the layer to which the logging grid area belongs is determined as the adjusted velocity value corresponding to the logging grid area; Based on the adjustment velocity value corresponding to each logging grid area and the interpolation algorithm, the adjustment velocity values ​​corresponding to other grid areas in the target area besides the logging grid areas are determined.

3. The method according to claim 1, characterized in that, The step of determining the iteration weight value corresponding to the current iteration number based on the initial iteration weight value and the current iteration number includes: The iteration weight value corresponding to the current iteration number is calculated based on the following formula: Among them, the It is the current iteration number, the It is the iteration weight value corresponding to the current iteration number, the These are the initial iteration weight values, the stated It is a preset positive value.

4. The method according to claim 1, characterized in that, The step of determining the first update speed model based on the iteration weight value corresponding to the current iteration number, the adjustment speed values ​​corresponding to the multiple grid regions, and the initial speed model includes: For multiple grid regions with corresponding adjustment speed values, the first update speed value corresponding to the grid region is calculated based on the following formula: Among them, the It is the current iteration number, the It is the index of the grid region, the It is the first The first update speed value corresponding to each grid region, the It is the iteration weight value corresponding to the current iteration number, the It is the first The adjustment speed value corresponding to each grid region, the It is the first The initial velocity values ​​corresponding to each grid region; For multiple grid regions for which no corresponding adjustment speed value has been determined, the initial speed value corresponding to the grid region is determined as the first update speed value corresponding to the grid region.

5. The method according to claim 1, characterized in that, The step of determining the first update speed model based on the iteration weight value corresponding to the current iteration number, the adjustment speed values ​​corresponding to the multiple grid regions, and the initial speed model includes: Based on the prior information and prior weight values ​​of the aforementioned regions, the initial velocity model is locally adjusted to obtain the locally adjusted velocity model corresponding to the initial velocity model. Based on the iteration weight value corresponding to the current iteration number and the adjustment speed value corresponding to the multiple grid regions, the local adjustment speed model is globally adjusted to obtain the first update speed model.

6. The method according to claim 1, characterized in that, The step of determining the velocity update difference corresponding to the first update rate value of each target grid region based on the travel time of the multiple first arrival waves, the propagation distance of each first arrival wave in the target grid region it passes through, and the first update rate value of each target grid region corresponding to the multiple first arrival waves includes: For each first arrival wave, a reference propagation time for the first arrival wave in each target grid region is determined based on the propagation distance of the first arrival wave in each target grid region it passes through and the first update rate value of each target grid region corresponding to the first arrival wave. The sum of the reference propagation times of the first arrival wave in each target grid region it passes through is calculated as the total reference propagation time of the first arrival wave; Based on the reference total propagation time of the first arrival wave and the travel time of the first arrival wave, the propagation time update difference of the first arrival wave in each target grid region it passes through is determined; Based on the propagation time update difference of the first arrival wave in each target grid region it passes through and the propagation distance of the first arrival wave in each target grid region it passes through, the velocity update difference corresponding to the adjustment velocity value of each target grid region is determined.

7. A device for determining a velocity model, characterized in that, The device includes: A module is established to obtain the initial velocity model corresponding to the target area. The initial velocity model includes multiple data channels with different position coordinates. Each data channel includes at least one grid area corresponding to a different depth and an initial velocity value corresponding to each grid area. The first determining module is used to determine the adjustment speed values ​​corresponding to multiple grid regions in the target region based on prior information of some regions in the target region and an interpolation algorithm; The second determining module is used to determine the iteration weight value corresponding to the current iteration number based on the initial iteration weight value and the current iteration number, wherein the initial iteration weight value is the iteration weight value corresponding to the first iteration, and the iteration weight value corresponding to the current iteration number is negatively correlated with the current iteration number; The third determining module is used to determine a first update speed model based on the iteration weight value corresponding to the current iteration number, the adjustment speed value corresponding to the multiple grid regions, and the initial speed model, wherein the first update speed model includes the first update speed value corresponding to the initial speed value of the multiple grid regions; The acquisition module is used to acquire the travel times of multiple first arrival waves corresponding to the target area, wherein the travel times of the multiple first arrival waves are acquired through seismic data corresponding to the target area; The fourth determining module is used to determine the propagation distance of each of the multiple first arrival waves in each target grid region it passes through, based on the ray tracing algorithm, the first update velocity model, and the source point coordinates and multiple receiver coordinates in the seismic data corresponding to the target region. The fifth determining module is used to determine the velocity update difference corresponding to the first update velocity value of each target grid region based on the travel time of the multiple first arrival waves, the propagation distance of each first arrival wave in the target grid region it passes through, and the first update velocity value of each target grid region corresponding to the multiple first arrival waves. The update module is used to update the first update speed model based on the speed update difference corresponding to the first update speed value of each target grid region to obtain a second update speed model, wherein the second update speed model includes the second update speed value corresponding to the first update speed value of the plurality of grid regions; The judgment module is used to stop the iteration if the preset conditions are met and determine the second update speed model as the speed model, and to determine the second update speed model as the initial speed model if the preset conditions are not met.

8. The apparatus according to claim 7, characterized in that, The third determining module is used for: Based on the prior information and prior weight values ​​of the aforementioned regions, the initial velocity model is locally adjusted to obtain the locally adjusted velocity model corresponding to the initial velocity model. Based on the iteration weight value corresponding to the current iteration number and the adjustment speed value corresponding to the multiple grid regions, the local adjustment speed model is globally adjusted to obtain the first update speed model.

9. A computer device, characterized in that, The computer device includes a processor and a memory, the memory storing at least one instruction, which is loaded and executed by the processor to perform the operation performed by the method for determining the speed model as described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, The storage medium stores at least one instruction, which is loaded and executed by a processor to perform the operation performed by the method for determining the speed model as described in any one of claims 1 to 6.

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