Speed modeling method and device, electronic equipment and storage medium

Abstract

Embodiments of the present application provide a speed modeling method and device, electronic equipment and storage medium; the method comprises determining the actual horizon data of the i iteration cycle interpretation according to the pre-stack depth migration data of the i iteration cycle through horizon interpretation; determining the expected horizon data of the seismic interpretation of the i+1 iteration cycle according to the prior geological information of the target complex structure region, the geological understanding of the adjacent work area and the interpretation results of the previous processing link; determining the i+1 iteration velocity model according to the expected horizon data, the actual horizon data and the isotropic depth domain velocity model based on the tomographic inversion mode of ray tracing; determining whether to output the i+1 iteration velocity model as the velocity modeling result according to the pre-stack depth migration data corresponding to the i+1 iteration velocity model of the i+1 iteration cycle and the iteration end condition. The method obtains the velocity model conforming to the geological understanding, effectively solves the pre-stack depth migration in the mountain complex structure region, and improves the imaging effect of the seismic data.

Description

Technical Field

[0001] This invention relates to the field of seismic exploration technology for oil and gas in complex structural areas, specifically to a velocity modeling method, apparatus, electronic device, and storage medium. Background Technology

[0002] Similar to how CT scans reveal the internal structure of the human body, seismic data processing requires imaging to obtain information about subsurface structures. Imaging relies on CMP gathers and velocity models, and the accuracy of the velocity model determines the accuracy of the obtained stratigraphic information. Currently, commonly used depth-domain velocity modeling methods include model tomography inversion and grid tomography inversion. Model tomography inversion, based on interpreted horizon control, mainly involves velocity inversion by obtaining ray paths and residual delays at multiple velocity interfaces in a simple layered model. Its advantages are: it can simplify complex geological models into seismic horizon models under the constraints of geological structures, and the model has geological significance; its disadvantages are: it requires the interpretation of geological horizons, which is difficult in low signal-to-noise ratio areas, resulting in low accuracy of the delineated velocity interface model, and this simplified model can only invert the trend velocity field, lacking detailed information about inter-layer velocities. Grid tomography inversion method: Velocity inversion is performed by obtaining ray paths and residual delays in global grid space. It does not require interpretation of stratigraphy, is purely data-driven, and overcomes the shortcomings of layered models in failing to depict the details of inter-layer velocity. The inversion accuracy is relatively high, and it can obtain relatively accurate high-frequency components of the velocity field. However, the inversion model does not have the constraint of geological stratigraphy, and it is not easy to converge to the actual velocity model. It may even produce inversion results that do not conform to geological laws.

[0003] Therefore, simple underground structures can be accurately imaged using conventional velocity modeling methods; however, for complex tectonic regions, relying directly on automated calculations may increase the uncertainty of the inversion and introduce false tectonic information.

[0004] Therefore, current technology has the technical problem that the velocity modeling method is unreasonable for complex structural regions. Summary of the Invention

[0005] To alleviate the technical problem of unreasonable velocity modeling methods for complex structural regions in current technologies, embodiments of the present invention provide a velocity modeling method, apparatus, electronic device, and storage medium.

[0006] In a first aspect, embodiments of the present invention provide a velocity modeling method for seismic data in complex tectonic regions, comprising:

[0007] Based on the pre-stack depth migration data of the i-th iteration cycle, the actual stratigraphic data interpreted in the i-th iteration cycle is determined through stratigraphic interpretation.

[0008] Based on prior geological information of the target complex tectonic region, geological understanding of adjacent work areas, and interpretation results from the preliminary processing stage, the expected stratigraphic data for the seismic interpretation in the (i+1)th iteration cycle are determined; the prior geological information includes well logging and drilling information, and the preliminary processing stage includes pre-stack time migration.

[0009] The tomographic inversion model based on ray tracing determines the velocity model for the (i+1)th iteration based on the expected layer data interpreted by the seismic interpretation in the (i+1)th iteration cycle, the actual layer data interpreted in the (i)th iteration cycle, and the isotropic depth domain velocity model.

[0010] Based on the pre-stack depth migration data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition, determine whether to output the (i+1)th iteration velocity model as the velocity modeling result of the seismic data corresponding to the target complex tectonic region.

[0011] In some implementations, determining whether to output the (i+1)th iteration velocity model as a velocity modeling result based on the pre-stack depth offset data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition includes:

[0012] Determine whether the pre-stack depth migration data of the (i+1)th iteration period matches the prior geological information;

[0013] Determine whether the common imaging point gather of the pre-stack depth offset data in the (i+1)th iteration period is flattened;

[0014] Determine whether the wavegroup characteristics of the pre-stack depth migration data in the (i+1)th iteration period are reasonable;

[0015] If the pre-stack depth migration data of the (i+1)th iteration period matches the prior geological information, the common imaging point gather is flattened, and the wave group characteristics are reasonable, then the (i+1)th iteration velocity model is output as the velocity modeling result.

[0016] In some implementations, before the step of determining the actual stratigraphic data interpreted in the i-th iteration period based on the pre-stack depth migration data of the i-th iteration period through stratigraphic interpretation, the method further includes:

[0017] Obtain the seismic imaging data volume corresponding to the mountain earthquake data;

[0018] Based on the stratigraphic interpretation data on the seismic imaging data volume, determine a preset number of phase axes of marker strata;

[0019] Stratigraphic tracking is performed on the phase axis of the marker strata to obtain the actual stratigraphic data interpreted in the i-th iteration cycle.

[0020] In some implementations, based on prior geological information and seismic data of the target complex tectonic region, the expected stratigraphic data for the seismic interpretation in the (i+1)th iteration period are determined, including:

[0021] Based on the seismic data of the target complex tectonic region, pre-stack time migration data are determined;

[0022] The pre-stack time offset data is converted into depth domain data;

[0023] Based on the prior geological information, stratigraphic interpretation is performed on the depth domain data transformed by the pre-stack time migration to determine the desired stratigraphic data.

[0024] In some implementations, before the step of determining the desired layer data for the (i+1)th iteration period based on the pre-stack depth offset data for the i-th iteration period, the method further includes:

[0025] A preset tomographic inversion mode is determined, which includes a model tomographic inversion mode or a grid tomographic inversion mode;

[0026] The isotropic depth domain velocity model is determined based on the preset tomographic inversion mode.

[0027] In some implementations, the velocity model for the (i+1)th iteration is determined using a ray-tracing-based tomographic inversion mode, based on the expected horizon data interpreted in the seismic interpretation of the (i+1)th iteration cycle, the actual horizon data interpreted in the i-th iteration cycle, and the isotropic depth domain velocity model. This includes:

[0028] Based on the actual stratigraphic data and the expected stratigraphic data of the seismic interpretation in the (i+1)th iteration period, determine the residual for the i-th iteration period;

[0029] The tomographic inversion mode based on ray tracing determines the velocity model for the (i+1)th iteration based on the residual of the i-th iteration cycle, the isotropic depth domain velocity model, and the layer interpretation data.

[0030] In some implementations, the velocity model for the (i+1)th iteration is determined using a ray-tracing-based tomographic inversion mode, based on the residual of the i-th iteration cycle, the isotropic depth-domain velocity model, and the stratigraphic interpretation data. This includes:

[0031] The update variables for the anisotropic parameters of each target point are determined based on the isotropic depth domain velocity model; the target points include the target points between the three-dimensional mesh and the ray pair of the i-th iteration velocity model;

[0032] Based on the residual of the i-th iteration cycle and the layer interpretation data, determine the update variables for the P-wave velocity and the depth value of each target point;

[0033] Based on the update variables of the anisotropy parameters, the update variables of the P-wave velocity, and the update variables of the depth values, the travel time variables of each ray pair for the model parameters are determined.

[0034] Based on the travel time variables and the target matrix vector, the (i+1)th iteration velocity model is obtained.

[0035] Secondly, embodiments of the present invention provide a velocity modeling apparatus for seismic data in complex tectonic regions, the apparatus comprising:

[0036] The first module is used to determine the actual stratigraphic data interpreted in the i-th iteration cycle based on the pre-stack depth migration data in the i-th iteration cycle through stratigraphic interpretation.

[0037] The second module is used to determine the expected stratigraphic data for the seismic interpretation in the (i+1)th iteration period based on the prior geological information of the target complex structural area, the geological understanding of adjacent work areas, and the interpretation results of the pre-processing stage; the prior geological information includes well logging and drilling information, and the pre-processing stage includes the pre-stack time migration.

[0038] The third module is used for the tomographic inversion mode based on ray tracing. It determines the velocity model for the (i+1)th iteration based on the expected layer data of the seismic interpretation in the (i+1)th iteration cycle, the actual layer data interpreted in the (i)th iteration cycle, and the isotropic depth domain velocity model.

[0039] The fourth module is used to determine whether to output the (i+1)th iteration velocity model as the velocity modeling result of the seismic data corresponding to the target complex tectonic region, based on the pre-stack depth migration data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition.

[0040] Thirdly, embodiments of the present invention provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the computer program, when executed by the processor, implements the method described in the first aspect.

[0041] Fourthly, embodiments of the present invention provide a storage medium storing a computer program, which, when executed by one or more processors, implements the method described in the first aspect.

[0042] Compared with the prior art, one or more embodiments of the present invention can bring at least the following beneficial effects:

[0043] This invention provides a velocity modeling method, apparatus, electronic device, and storage medium. The method includes determining the actual stratigraphic data interpreted in the i-th iteration cycle based on pre-stack depth migration data and stratigraphic interpretation; determining the expected stratigraphic data for seismic interpretation in the (i+1)-th iteration cycle based on prior geological information of the target complex tectonic region, geological understanding of adjacent work areas, and interpretation results from the pre-processing stage; the prior geological information includes well logging and drilling information, and the pre-processing stage includes previous pre-stack time migration; determining the (i+1)-th iteration velocity model based on a ray-tracing tomographic inversion mode, using the expected stratigraphic data, the actual stratigraphic data, and an isotropic depth domain velocity model for the (i+1)-th iteration cycle; and determining whether to output the (i+1)-th iteration velocity model as the velocity modeling result for the seismic data corresponding to the target complex tectonic region based on the pre-stack depth migration data corresponding to the (i+1)-th iteration cycle of the (i+1)-th iteration velocity model and the iteration termination condition. In the method provided in this scheme, velocity modeling is performed under the constraints of prior geological information to obtain a velocity model that conforms to geological understanding. Prestack depth migration is then performed using this velocity model. The processed results have clear wave group characteristics, clear stratigraphic contact relationships, and stratigraphic distribution characteristics and structures that conform to the geological understanding of this area and adjacent areas. The common imaging point gathers have good flattening effect, effectively solving the problem of prestack depth migration in complex tectonic areas and improving the imaging effect of seismic data. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of a first flowchart of the velocity modeling method provided in an embodiment of this application;

[0046] Figure 2 This is a second flowchart illustrating the velocity modeling method provided in the embodiments of this application;

[0047] Figure 3 A pre-stack depth migration imaging profile of adjacent work areas provided in an embodiment of this application;

[0048] Figure 4 The imaging data profiles before and after using the velocity modeling method of the present invention are provided in the embodiments of this application.

[0049] Figure 5 This is a schematic diagram of the speed modeling device provided in an embodiment of this application.

[0050] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation

[0051] The following detailed description of the embodiments of this application, in conjunction with the accompanying drawings, will provide a thorough understanding of how this application uses technical means to solve technical problems and achieve corresponding technical effects, enabling its implementation. The embodiments of this application and the various features within them can be combined with each other without conflict, and all resulting technical solutions are within the protection scope of this application.

[0052] Furthermore, numerous specific details are set forth in the following description for purposes of explanation, in order to provide a thorough understanding of the embodiments of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without the specific details herein or the particular methods described.

[0053] Example 1

[0054] Figure 1 For a first flowchart illustrating the velocity modeling method provided in this application embodiment, please refer to [link / reference]. Figure 1 The velocity modeling method provided in this embodiment includes:

[0055] Step S110: Based on the pre-stack depth offset data of the i-th iteration cycle, determine the actual stratigraphic data interpreted in the i-th iteration cycle through stratigraphic interpretation.

[0056] In some implementations, before the step of determining the actual stratigraphic data interpreted in the i-th iteration period based on the pre-stack depth migration data of the i-th iteration period through stratigraphic interpretation, the method further includes: acquiring the seismic imaging data volume corresponding to the seismic data of the complex tectonic region; determining a preset number of phase axes of marker strata based on the stratigraphic interpretation data on the seismic imaging data volume; and performing stratigraphic tracking on the phase axes of the marker strata to obtain the actual stratigraphic data interpreted in the i-th iteration period.

[0057] Specifically, by interpreting the stratigraphic data on the seismic imaging data volume, stratigraphic tracking is performed on the phase axes of several sets of marker strata to obtain actual stratigraphic data.

[0058] In some implementations, before determining the desired layer data for the (i+1)th iteration period based on the pre-stack depth offset data for the i-th iteration period, the method further includes: determining a preset tomographic inversion mode, wherein the preset tomographic inversion mode includes a model tomographic inversion mode or a grid tomographic inversion mode; and determining the isotropic depth domain velocity model based on the preset tomographic inversion mode.

[0059] Specifically, an isotropic depth domain velocity model is obtained through model tomography inversion or network tomography inversion; based on this, subsequent work is carried out.

[0060] Step S120: Based on the prior geological information of the target complex structural area, the geological understanding of adjacent work areas, and the interpretation results of the previous processing, determine the expected stratigraphic data for the seismic interpretation in the (i+1)th iteration cycle.

[0061] In this application, the prior geological information includes well logging and drilling information, such as well logging curves and drilling depth values; the geological understanding includes stratigraphic interpretation; and the preprocessing stage includes pre-stack time migration. In this embodiment, the richness of geological information directly determines the reliability of subsequent velocity model inversion. Well logging and drilling information can finely control the vertical velocity and depth values ​​near the well point in the vertical direction, while stratigraphic interpretation data can constrain and control them in the horizontal direction.

[0062] In some implementations, determining the expected stratigraphic data for the seismic interpretation of the (i+1)th iteration period based on prior geological information and seismic data of the target complex tectonic region includes: determining pre-stack time migration data based on the seismic data of the target complex tectonic region; converting the pre-stack time migration data into depth domain data; and determining the expected stratigraphic data based on the prior geological information, according to the stratigraphic interpretation of the seismic imaging data volume and the stratigraphic interpretation of the depth domain data.

[0063] Specifically, the geological understanding and pre-stack time migration results of this work area and adjacent work areas can provide global guidance for the interpretation of stratigraphic layers on the depth-domain seismic imaging data volume. If there are local areas on the seismic imaging data volume that do not conform to the geological understanding, the stratigraphic interpretation can be performed according to the geological understanding. Alternatively, stratigraphic interpretation can be tested on the data converted from pre-stack time migration to the depth domain to obtain the expected stratigraphic data for the (i+1)th iteration period.

[0064] Step S130: Based on the ray tracing tomographic inversion mode, determine the velocity model for the (i+1)th iteration according to the expected layer data of the seismic interpretation in the (i+1)th iteration cycle, the actual layer data interpreted in the (i)th iteration cycle, and the isotropic depth domain velocity model.

[0065] In some implementations, the velocity model for the (i+1)th iteration is determined using a ray-tracing-based tomographic inversion mode, based on the expected horizon data interpreted in the seismic interpretation of the (i+1)th iteration period, the actual horizon data interpreted in the (i)th iteration period, and the isotropic depth domain velocity model. This includes: determining the residual for the (i)th iteration period based on the expected horizon data interpreted in the seismic interpretation of the (i+1)th iteration period; and determining the velocity model for the (i+1)th iteration using the ray-tracing-based tomographic inversion mode, based on the residual for the (i)th iteration period, the isotropic depth domain velocity model, and the horizon interpretation data.

[0066] In this embodiment, the residual between the actual stratum data and the expected stratum data is calculated.

[0067] In some implementations, the (i+1)th iteration velocity model is determined using a ray-tracing-based tomographic inversion mode, based on the residual of the i-th iteration cycle, the isotropic depth domain velocity model, and the stratigraphic interpretation data. This includes: determining update variables for the anisotropic parameters of each target point based on the isotropic depth domain velocity model; the target point includes the target point between the 3D mesh of the i-th iteration velocity model and the ray pair; determining update variables for the P-wave velocity and the depth value of each target point based on the residual of the i-th iteration cycle and the stratigraphic interpretation data; determining travel time variables for the model parameters of each ray pair based on the update variables for the anisotropic parameters, the P-wave velocity, and the depth value; and obtaining the (i+1)th iteration velocity model based on the travel time variables and the target matrix vector.

[0068] Specifically, combining residual and stratigraphic interpretation data with an isotropic depth-domain velocity model, the velocity model is updated using ray-tracing-based tomographic inversion. During tomographic inversion, the target points formed by the model's 3D mesh and ray pairs are regular in the horizontal direction but irregular in the vertical direction; these mesh points correspond to the structural interfaces of the interpreted stratigraphic layers. The updated model parameters are displayed as a sparse mesh, with rays emanating from a finer horizontal mesh. The travel-time variables of the model parameters for each ray pair are given by the following equation:

[0069]

[0070] Where i can be considered as the index number of the target point launched onto the structural interface of the velocity model. ΔV, Δε, Δδ, and Δz represent the update variables for the P-wave velocity, the two anisotropic parameters, and the depth value, respectively. Represents the following matrix parts:

[0071]

[0072] Where t is the total travel time of the ray pairs, and m = V, ε, δ, z; each ray pair generates an equation, which together define an overdetermined system of linear equations (the number of rays is much greater than the number of model nodes). This can be written as a matrix-vector expression:

[0073] A V ΔV+A ε Δε+A δ Δδ+A z Δz=0 (3)

[0074] By solving this matrix, an updated velocity model can be obtained, and the pre-stack depth migration result of this velocity model approximates the prior geological information.

[0075] Step S140: Based on the pre-stack depth migration data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition, determine whether to output the (i+1)th iteration velocity model as the velocity modeling result of the seismic data corresponding to the target complex tectonic region.

[0076] In some implementations, determining whether to output the (i+1)th iteration velocity model as a velocity modeling result based on the (i+1)th iteration velocity model corresponding to the (i+1)th iteration period pre-stack depth migration data and the iteration termination condition includes: determining whether the (i+1)th iteration period pre-stack depth migration data matches the prior geological information; determining whether the common imaging point gathers of the (i+1)th iteration period pre-stack depth migration data are flattened; determining whether the wave group characteristics of the (i+1)th iteration period pre-stack depth migration data are reasonable; if the (i+1)th iteration period pre-stack depth migration data matches the prior geological information, the common imaging point gathers are flattened, and the wave group characteristics are reasonable, then the (i+1)th iteration velocity model is output as a velocity modeling result; if the (i+1)th iteration period pre-stack depth migration data does not match the prior geological information, the common imaging point gathers are not flattened, and the wave group characteristics are unreasonable, then it is necessary to re-determine the actual stratigraphic data for the next iteration period based on the (i+1)th iteration period pre-stack depth migration data, and then execute steps S130 and S140.

[0077] Specifically, if the pre-stack depth migration results of the newly determined velocity modeling are consistent with prior geological knowledge, the CIP gathers (i.e., common imaging point gathers) after migration have good flattening effects, and the wave group characteristics on the pre-stack depth migration data volume are normal, and there is no abnormal cross-layer phenomenon of the same phase axis, then the velocity modeling is completed.

[0078] Figure 2 For a second flowchart illustrating the velocity modeling method provided in this application embodiment, please refer to [link / reference]. Figure 2 The velocity modeling method provided in this embodiment includes:

[0079] S210: Layer interpretation, obtaining the desired layer.

[0080] In this application, the prior geological information includes well logging curves, drilling depth values ​​(i.e., well logging and drilling data) and the geological understanding of adjacent similar work areas (i.e., the geological understanding of the structural distribution in adjacent work areas); among which, the geological understanding includes stratigraphic interpretation.

[0081] In this embodiment, the richness of geological information directly determines the reliability of subsequent velocity model inversion. Well logging and drilling information can finely control the vertical velocity and depth values ​​near the well point in the vertical direction, and stratigraphic interpretation data can constrain and control in the horizontal direction.

[0082] In this embodiment, by interpreting the seismic imaging data volume, stratigraphic tracking is performed on the phase axes of several marker strata to obtain actual stratigraphic data. Based on the geological understanding and pre-stack time migration results of this and adjacent work areas, the stratigraphic interpretation on the depth-domain seismic imaging data volume can be guided globally. If there are local areas on the seismic imaging data volume that do not conform to geological understanding, stratigraphic interpretation can be performed according to geological understanding. Alternatively, stratigraphic interpretation can be experimentally performed on the pre-stack time migration converted to depth-domain data to obtain the desired stratigraphic position.

[0083] S220: Determine the actual stratigraphic data.

[0084] In this embodiment, determining the actual stratum data includes:

[0085] S220a1: The i-th iteration cycle, obtain the velocity model for the i-th iteration cycle.

[0086] S220a2: Pre-stack depth offset.

[0087] S220a3: Actual stratigraphic data interpreted from pre-stack depth migration data.

[0088] S230: Find the difference between the two (obtain the residual).

[0089] In this embodiment, the residual between the actual stratum data and the expected stratum data is calculated.

[0090] S240: Tomographic inversion.

[0091] In this embodiment, the velocity model is updated using ray-tracing-based tomographic inversion technology, combining residuals, stratigraphic interpretation data, and an isotropic depth domain velocity model. During tomographic inversion, the target points formed by the model's 3D mesh and ray pairs are regular in the horizontal direction but irregular in the vertical direction; these mesh points correspond to the structural interfaces of the interpreted stratigraphic layers. The updated model parameters are displayed as a sparse mesh, with rays emanating from a finer horizontal mesh. The travel-time variables of the model parameters for each ray pair are given by the following equation:

[0092]

[0093] Where i can be considered as the index number of the target point launched onto the structural interface of the velocity model. ΔV, Δε, Δδ, and Δz represent the update variables for the P-wave velocity, the two anisotropic parameters, and the depth value, respectively. Represents the following matrix parts:

[0094]

[0095] Where t is the total travel time of the ray pairs, and m = V, ε, δ, z; each ray pair generates an equation, which together define an overdetermined system of linear equations (the number of rays is much greater than the number of model nodes). This can be written as a matrix-vector expression:

[0096] A V ΔV+A ε Δε+A δ Δδ+A z Δz=0 (3)

[0097] S250: New speed model.

[0098] In this embodiment, by solving the matrix-vector expression (3) in the previous step, the updated velocity model can be obtained. The pre-stack depth migration result of the velocity model approximates the prior geological information.

[0099] S260: Pre-stack depth offset.

[0100] In this embodiment, pre-stack depth migration is performed using the new velocity model obtained in the previous step.

[0101] S270: Determine whether the underground structure conforms to geological understanding (whether the offset CIP gather is flattened; whether the wave group characteristics of the offset profile are reasonable).

[0102] In this embodiment, if the pre-stack depth migration results of the new velocity model are consistent with prior geological knowledge, the CIP gathers after migration have good flattening effect, and the wave group characteristics on the pre-stack depth migration data volume are normal, and there is no abnormal cross-layer phenomenon of the same phase axis, then the velocity modeling is completed; otherwise, it is necessary to re-interpret the stratigraphic level on the newly migrated depth domain data volume to obtain the new actual stratigraphic level, and then iterate through steps S230 and S240.

[0103] S280: Output the final result.

[0104] In this embodiment, following the previous step, after completing the velocity modeling, the final velocity modeling result is output.

[0105] In summary, this embodiment performs velocity modeling under the constraints of prior geological information, resulting in a velocity model that conforms to geological understanding. Prestack depth migration is then performed using this velocity model. The processed results show clear wave group characteristics, well-defined stratigraphic contact relationships, and stratigraphic distribution and structure that are consistent with geological understanding of this and adjacent areas. The common imaging point gathers have good flattening effects, effectively solving the problem of prestack depth migration in mountainous and complex tectonic areas and improving the imaging effect of seismic data.

[0106] Example 2

[0107] Figure 5 For a schematic diagram of the velocity modeling device provided in the embodiments of this application, please refer to [link / reference]. Figure 5 The velocity modeling device provided in this embodiment includes:

[0108] The first module 510 is used to determine the actual stratigraphic data interpreted in the i-th iteration cycle based on the pre-stack depth offset data in the i-th iteration cycle through stratigraphic interpretation.

[0109] The second module 520 is used to determine the expected stratigraphic data for the seismic interpretation in the (i+1)th iteration period based on the prior geological information of the target complex structural area, the geological understanding of adjacent work areas, and the interpretation results of the pre-processing stage; the prior geological information includes well logging and drilling information, and the pre-processing stage includes the pre-stack time migration.

[0110] The third module 530 is used for the tomographic inversion mode based on ray tracing, and determines the velocity model for the (i+1)th iteration based on the expected layer data of the seismic interpretation in the (i+1)th iteration cycle, the actual layer data interpreted in the (i)th iteration cycle, and the isotropic depth domain velocity model.

[0111] The fourth module 540 is used to determine whether to output the (i+1)th iteration velocity model as the velocity modeling result of the seismic data corresponding to the target complex tectonic region, based on the pre-stack depth migration data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition.

[0112] Specific implementation methods based on the above modules have been detailed in Implementation 1 and will not be repeated here.

[0113] Based on the foregoing description, this application will now be explained in detail in conjunction with specific scenarios.

[0114] The velocity modeling method of this application yielded a velocity model consistent with geological understanding, effectively solving the problem of pre-stack depth migration in complex structures and improving the imaging effect of seismic data. Specific results are described in the research examples below.

[0115] The work area is located in the high and steep fold belt of the X Basin. The terrain has the characteristics of both hills and mountains, with an elevation between 300m and 1300m. The mountains are high and the slopes are steep, with many ravines, cliffs and steep ridges. The terrain is highly undulating. Surface conditions such as surface collapse, steep cliffs, steep ridges, steep slopes, half-mountains, piedmont fracture zones, landslides, exposed rocks and fractured areas are distributed throughout the area, making the surface seismic geological conditions of the work area quite complex.

[0116] The geological structure of the steep structures and limestone areas in the study area is complex, with well-developed faults and large variations in strata dip angles, which have a significant impact on the propagation of seismic waves and result in a complex wave field. In particular, the reflected wave field is complex, with a low signal-to-noise ratio, poor continuity, and difficulty in imaging, especially in the steep structural parts. Further investigation is needed to determine the structural details and fault distribution characteristics through pre-stack depth migration.

[0117] like Figure 3 This is a profile of pre-stack depth migration imaging data from an adjacent work area. The eastern flank of the fault in the O3w stratum is an anticline structure, consistent with geological findings from drilling and imaging logging. In similar surface and subsurface conditions within this work area, pre-stack time migration imaging results indicate that the eastern flank of the fault in this stratum is an anticline structure. However, based on pre-stack depth migration data obtained using conventional modeling methods, the eastern flank of the fault in this stratum appears to be a monoclinic stratum, potentially indicating an inappropriate depth-domain velocity model.

[0118] The pre-stack time-migration data volume is scaled down to the depth domain. The O3w layer interpreted in the depth domain is taken as the desired layer, and the O3w layer interpreted in the current pre-stack depth-migration data volume is taken as the actual layer. The difference between the two is calculated. This difference is input, and the current depth-domain velocity model and the actual layer are used to obtain the updated velocity model through the ray tracing inversion algorithm described above. The pre-stack depth-migration data volumes corresponding to the velocity models before and after the update are shown below. Figure 4 As shown, the velocity model obtained by the velocity modeling method of this application makes the imaging structure more consistent with geological understanding (this is a qualitative evaluation; in addition, it is still necessary to combine the offset CIP gather flattening, whether it conforms to well logging data, and other criteria to judge the reliability of the imaging results).

[0119] Example 3

[0120] This embodiment provides an electronic device, including a memory and a processor. The memory stores a calculator program, which, when executed by the processor, implements the speed modeling method described in Embodiment 1. It is understood that the electronic device may further include an input / output (I / O) interface and communication components.

[0121] The processor is used to execute all or part of the steps in the speed modeling method as described in Embodiment 1. The memory is used to store various types of data, which may include, for example, instructions for any application or method in the terminal device, as well as application-related data.

[0122] The processor may be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic components, and is used to execute the speed modeling method in Embodiment 1 above.

[0123] The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0124] Example 4

[0125] This embodiment also provides a computer-readable storage medium, such as flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disk, optical disk, server, app store, etc., on which a computer program is stored. When the computer program is executed by a processor, it can implement the following method steps:

[0126] Based on the pre-stack depth migration data of the i-th iteration cycle, the actual stratigraphic data interpreted in the i-th iteration cycle is determined through stratigraphic interpretation.

[0127] Based on prior geological information of the target complex tectonic region, geological understanding of adjacent work areas, and interpretation results from the preliminary processing stage, the expected stratigraphic data for the seismic interpretation in the (i+1)th iteration cycle are determined; the prior geological information includes well logging and drilling information, and the preliminary processing stage includes pre-stack time migration.

[0128] The tomographic inversion model based on ray tracing determines the velocity model for the (i+1)th iteration based on the expected layer data interpreted by the seismic interpretation in the (i+1)th iteration cycle, the actual layer data interpreted in the (i)th iteration cycle, and the isotropic depth domain velocity model.

[0129] Based on the pre-stack depth migration data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition, determine whether to output the (i+1)th iteration velocity model as the velocity modeling result of the seismic data corresponding to the target complex tectonic region.

[0130] For a detailed description of the above method steps, please refer to Example 1. This example will not be repeated here.

[0131] In summary, this application provides a velocity modeling method, apparatus, electronic device, and storage medium. The method includes determining the actual stratigraphic data interpreted in the i-th iteration cycle based on the pre-stack depth migration data of the i-th iteration cycle through stratigraphic interpretation; determining the expected stratigraphic data for the seismic interpretation of the (i+1)-th iteration cycle based on prior geological information of the target complex tectonic region, geological understanding of adjacent work areas, and interpretation results from the pre-processing stage; the prior geological information includes well logging and drilling information, and the pre-processing stage includes previous pre-stack time migration; determining the (i+1)-th iteration velocity model based on a ray-tracing tomographic inversion mode, according to the expected stratigraphic data of the seismic interpretation of the (i+1)-th iteration cycle, the actual stratigraphic data interpreted in the i-th iteration cycle, and an isotropic depth domain velocity model; and determining whether to output the (i+1)-th iteration velocity model as the velocity modeling result of the seismic data corresponding to the target complex tectonic region based on the pre-stack depth migration data of the i+1-th iteration cycle corresponding to the (i+1)-th iteration velocity model and the iteration termination condition. In the method provided in this scheme, velocity modeling is performed under the constraints of prior geological information to obtain a velocity model that conforms to geological understanding. Prestack depth migration is then performed using this velocity model. The processed results have clear wave group characteristics, clear stratigraphic contact relationships, and stratigraphic distribution characteristics and structures that conform to the geological understanding of this area and adjacent areas. The common imaging point gathers have good flattening effect, effectively solving the problem of prestack depth migration in mountainous complex tectonic areas and improving the imaging effect of seismic data.

[0132] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0133] Although the embodiments disclosed in this application are as described above, the content is merely for the purpose of facilitating understanding of this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A velocity modeling method for seismic data in complex tectonic regions, characterized in that, include: Based on the pre-stack depth migration data of the i-th iteration cycle, the actual stratigraphic data interpreted in the i-th iteration cycle is determined through stratigraphic interpretation. Based on prior geological information of the target complex tectonic region, geological understanding of adjacent work areas, and interpretation results from the preliminary processing stage, the expected stratigraphic data for the seismic interpretation in the (i+1)th iteration cycle are determined; the prior geological information includes well logging and drilling information, and the preliminary processing stage includes pre-stack time migration. The tomographic inversion model based on ray tracing determines the velocity model for the (i+1)th iteration based on the expected layer data interpreted by the seismic interpretation in the (i+1)th iteration cycle, the actual layer data interpreted in the (i)th iteration cycle, and the isotropic depth domain velocity model. Based on the pre-stack depth migration data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition, determine whether to output the (i+1)th iteration velocity model as the velocity modeling result of the seismic data corresponding to the target complex tectonic region. The geological understanding of the adjacent work areas includes pre-stack depth migration imaging data profiles of the adjacent work areas; The step of determining whether to output the (i+1)th iteration velocity model as a velocity modeling result based on the pre-stack depth offset data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition includes: Determine whether the pre-stack depth migration data of the (i+1)th iteration period matches the prior geological information; Determine whether the common imaging point gather of the pre-stack depth offset data in the (i+1)th iteration period is flattened; Determine whether the wavegroup characteristics of the pre-stack depth migration data in the (i+1)th iteration period are reasonable; If the pre-stack depth migration data of the (i+1)th iteration period matches the prior geological information, the common imaging point gather is flattened, and the wave group characteristics are reasonable, then the (i+1)th iteration velocity model is output as the velocity modeling result. The method further includes: correcting the desired stratigraphic data by comparing the pre-stack depth migration imaging profile of the adjacent work area with the structural morphology of the data in the current work area; The step of determining whether the wave group characteristics of the pre-stack depth migration data in the (i+1)th iteration period are reasonable includes: detecting whether there is an abnormal cross-layer phenomenon of the same phase axis in the pre-stack depth migration data volume; if not, the wave group characteristics are considered reasonable.

2. The velocity modeling method according to claim 1, characterized in that, Before the step of determining the actual stratigraphic data interpreted in the i-th iteration period based on the pre-stack depth migration data of the i-th iteration period through stratigraphic interpretation, the following steps are also included: Obtain the seismic imaging data volume corresponding to the seismic data of the complex tectonic region; Based on the stratigraphic interpretation data on the seismic imaging data volume, determine a preset number of phase axes of marker strata; Stratigraphic tracking is performed on the phase axis of the marker strata to obtain the actual stratigraphic data interpreted in the i-th iteration cycle.

3. The velocity modeling method according to claim 2, characterized in that, Based on prior geological information and seismic data of the target complex tectonic region, the expected stratigraphic data for seismic interpretation in the (i+1)th iteration period are determined, including: Based on the seismic data of the target complex tectonic region, pre-stack time migration data are determined; The pre-stack time offset data is converted into depth domain data; Based on the prior geological information, the desired stratigraphic data is determined according to the stratigraphic interpretation of the seismic imaging data volume and the stratigraphic interpretation of the depth domain data.

4. The velocity modeling method according to claim 1, characterized in that, Before the step of determining the expected stratigraphic data for the (i+1)th iteration period based on the pre-stack depth migration data for the i-th iteration period, the following steps are also included: A preset tomographic inversion mode is determined, which includes a model tomographic inversion mode or a grid tomographic inversion mode; The isotropic depth domain velocity model is determined based on the preset tomographic inversion mode.

5. The velocity modeling method according to any one of claims 1 to 4, characterized in that, Using a ray-tracing-based tomographic inversion model, based on the expected horizon data interpreted in the (i+1)th iteration cycle, the actual horizon data interpreted in the i-th iteration cycle, and the isotropic depth domain velocity model, the velocity model for the (i+1)th iteration cycle is determined, including: Based on the actual stratigraphic data and the expected stratigraphic data of the seismic interpretation in the (i+1)th iteration period, determine the residual for the i-th iteration period; The tomographic inversion mode based on ray tracing determines the velocity model for the (i+1)th iteration based on the residual of the i-th iteration cycle, the isotropic depth domain velocity model, and the layer interpretation data.

6. The velocity modeling method according to claim 5, characterized in that, Using a ray-tracing-based tomographic inversion model, based on the residual of the i-th iteration cycle, the isotropic depth-domain velocity model, and the stratigraphic interpretation data, the (i+1)-th iteration velocity model is determined, including: The update variables for the anisotropic parameters of each target point are determined based on the isotropic depth domain velocity model; the target points include the target points between the three-dimensional mesh and the ray pair of the i-th iteration velocity model. Based on the residual of the i-th iteration cycle and the layer interpretation data, determine the update variables for the P-wave velocity and the depth value of each target point; Based on the update variables of the anisotropy parameters, the update variables of the P-wave velocity, and the update variables of the depth values, the travel time variables of each ray pair for the model parameters are determined. Based on the travel time variables and the target matrix vector, the (i+1)th iteration velocity model is obtained.

7. A velocity modeling device for seismic data in complex tectonic zones, characterized in that, include: The first module is used to determine the actual stratigraphic data interpreted in the i-th iteration cycle based on the pre-stack depth migration data in the i-th iteration cycle through stratigraphic interpretation. The second module is used to determine the expected stratigraphic data for the seismic interpretation in the (i+1)th iteration period based on the prior geological information of the target complex structural area, the geological understanding of adjacent work areas, and the interpretation results of the pre-processing stage; the prior geological information includes well logging and drilling information, and the pre-processing stage includes the pre-stack time migration. The third module is used for the tomographic inversion mode based on ray tracing. It determines the velocity model for the (i+1)th iteration based on the expected layer data of the seismic interpretation in the (i+1)th iteration cycle, the actual layer data interpreted in the (i)th iteration cycle, and the isotropic depth domain velocity model. The fourth module is used to determine whether to output the (i+1)th iteration velocity model as the velocity modeling result of the seismic data corresponding to the target complex tectonic region, based on the pre-stack depth migration data of the (i+1)th iteration period corresponding to the (i+1)th iteration velocity model and the iteration termination condition. The geological understanding of the adjacent work areas includes pre-stack depth migration imaging data profiles of the adjacent work areas; The fourth module is further configured to: Determine whether the pre-stack depth migration data of the (i+1)th iteration period matches the prior geological information; Determine whether the common imaging point gather of the pre-stack depth offset data in the (i+1)th iteration period is flattened; Determine whether the wavegroup characteristics of the pre-stack depth migration data in the (i+1)th iteration period are reasonable; If the pre-stack depth migration data of the (i+1)th iteration period matches the prior geological information, the common imaging point gather is flattened, and the wave group characteristics are reasonable, then the (i+1)th iteration velocity model is output as the velocity modeling result. The second module is further configured to: correct the desired layer data by comparing the pre-stack depth migration imaging profile of the adjacent work area with the structural morphology of the data in the current work area; The fourth module is also used to detect whether there is an abnormal cross-layer phenomenon of the same phase axis in the pre-stack depth offset data volume. If there is no such phenomenon, it is considered that the wave group characteristics are reasonable.

8. An electronic device, characterized in that, It includes a memory and a processor; the memory stores a computer program that, when executed by the processor, implements the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by one or more processors, implements the method as described in any one of claims 1 to 6.

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