OVT Domain VSP and Ground Seismic Data Depth Joint Imaging Method and Equipment

Abstract

This application provides a method and related equipment for joint depth imaging of OVT domain VSP and surface seismic data. It includes: acquiring 3D VSP data and surface seismic data; preprocessing; OVT gather segmentation; datum and well-side azimuth sector consistency correction; obtaining an isotropic depth domain layer velocity model updated with velocity based on previous pre-stack time migration; calculating the initial migration of the OVT domain joint pre-stack depth migration at the imaging point based on the isotropic depth domain layer velocity model; calculating the velocity update amount in each azimuth interval based on the residual curvature method; applying the average velocity model update amount to the isotropic depth domain layer velocity model according to azimuth, iteratively migrating to obtain an azimuth anisotropy-corrected OVT domain well-side joint depth domain imaging gather; and obtaining the OVT domain well-side joint imaging profile based on the azimuth anisotropy-corrected OVT domain well-side joint depth domain imaging gather. This improves the characterization accuracy of complex structures such as thin interbedded layers and small fault blocks.

Description

Technical Field

[0001] This application relates to the field of seismic exploration technology, and in particular to a method and device for joint imaging of depth using OVT domain VSP and ground seismic data. Background Technology

[0002] 3D VSP (Vertical Seismic Profiling) data offers high vertical resolution and rich azimuth anisotropy information; however, its illumination range is limited to the well perimeter area. Compared to 3D VSP data, surface seismic data, while having lower resolution, provides a wider illumination range. Combined imaging of 3D VSP and surface seismic data allows for mutual constraint, integrating the advantages of both data types. This approach is more suitable for imaging complex formations and azimuthally anisotropic media, meeting the growing demands for complex reservoir exploration.

[0003] Current imaging methods mostly focus on using VSP data to assist ground seismic data in migration imaging and seismic interpretation, or processing the two types of data separately before stitching them together. This results in insufficient accuracy of the obtained imaging data. Summary of the Invention

[0004] In view of this, the purpose of this application is to propose a method and related equipment for joint imaging of depth using OVT domain VSP and ground seismic data.

[0005] To achieve the above objectives, this application provides a method for joint depth imaging of OVT domain VSP and ground seismic data, comprising:

[0006] Acquire 3D VSP data and ground seismic data;

[0007] The 3D VSP data undergoes a first preprocessing step to obtain first 3D VSP data; the ground seismic data undergoes a second preprocessing step to obtain first ground seismic data.

[0008] The first 3D VSP data is subjected to a first partitioning process to obtain gather data of the 3D VSP OVT domain with multiple azimuth angles; the gather data of the 3D VSP OVT domain has azimuth angle information; the first ground seismic data is subjected to a second partitioning process to obtain gather data of the ground seismic OVT domain with multiple azimuth angles; the gather data of the ground seismic OVT domain has azimuth angle information.

[0009] The gather data in the 3D VSP OVT domain and the gather data in the ground seismic OVT domain are corrected to obtain corrected gather data in the 3D VSP OVT domain and corrected gather data in the ground seismic OVT domain; the reference plane and amplitude order of the corrected gather data in the 3D VSP OVT domain and the corrected gather data in the ground seismic OVT domain are the same.

[0010] Based on the pre-stack time offset, the velocity model of the isotropic depth domain layer after velocity update is obtained;

[0011] Based on the isotropic depth domain layer velocity model, the initial offset of the OVT domain joint pre-stack depth migration of the OVT domain gather data of the corrected 3D VSP OVT domain and the OVT domain gather data of the corrected ground seismic OVT domain at the imaging point is calculated to obtain the initial OVT domain well-to-surface joint depth domain imaging gather.

[0012] The velocity update amount of multiple azimuth intervals is calculated based on the residual curvature method to obtain the average velocity model update amount of the azimuth interval; the average velocity model update amount is applied to the initial depth domain layer velocity model according to the azimuth and iteratively offset to obtain the OVT domain well-ground joint depth domain imaging gather after azimuth anisotropy correction.

[0013] Based on the azimuth anisotropy-corrected OVT domain well-to-surface joint depth domain imaging gather, an OVT domain well-to-surface joint imaging profile is obtained.

[0014] In some embodiments, the first partitioning process is different from the second partitioning process; the correction process includes azimuth sector consistency correction process and reference plane consistency correction process.

[0015] The azimuth sector consistency correction process includes: aligning the imaging points of the 3D VSP OVT domain gathers with the center points of the surface elements of the ground seismic OVT domain gathers, and merging the azimuth angles of the ground seismic OVT gathers according to the azimuth sector division of the 3D VSP OVT gathers, so that the azimuth sectors of the imaging points of the 3D VSP OVT domain gathers are consistent with the center points of the surface elements of the ground seismic OVT domain gathers.

[0016] The reference plane consistency correction process includes correcting the reference plane of the 3D VSP OVT domain gather data and the reference plane of the ground seismic OVT domain gather data to the same reference plane.

[0017] In some embodiments, calculating the pre-stack depth migration of the corrected 3D VSP OVT domain gather data and the corrected ground seismic OVT domain gather data at the imaging point includes:

[0018] Through Calculate the pre-stack depth migration at the imaging point using the combined pre-stack depth migration of the corrected 3D VSP OVT domain gather data and the corrected ground seismic OVT domain gather data; where W G (X i ,X s ,X r X is the weighting function for gather data in the OVT domain of ground seismic earthquakes; s X i X r These represent the three-dimensional spatial locations of the seismic source, imaging point, and ground detector, respectively; d G (X s ,X r ,t G (α) represents ground seismic data; t G (α) represents the differential form of the minimum travel time ray tracing of a ground seismic event varying with the shot-receiver azimuth; α is the shot-receiver azimuth; ds is the differential length along the ray path; W V (X i ,X s ,X V ) is the weighting function for 3D VSP data; X V Position of the 3D VSP detector; For 3D VSP data; The derivative of the minimum travel time ray tracing for VSP; This represents the azimuth of the seismic source and the imaging point.

[0019] In some of these embodiments, t G (α)=t s +t r ; t is the propagation time; v is the wave speed;

[0020] In some embodiments, the calculation of velocity updates for multiple azimuth intervals based on the residual curvature method includes: for each azimuth interval, using the formula z(h,η)=z0(η)+a(η)h 2 Fit the residual time difference curve; where z0(η) is the theoretical depth of zero offset in the azimuth interval η, and a(η) is the curvature parameter of the azimuth interval, used for the azimuth anisotropy error of the reaction velocity model;

[0021] Through Calculate the velocity update in each azimuth angle interval; where v0(x i ) represents the isotropic velocity, h max This represents the maximum offset of the imaging gather.

[0022] In some embodiments, the first division process of the first 3D VSP data includes: dividing the shot collection range separately according to the source-image point azimuth angle, with each imaging point as the origin.

[0023] In some embodiments, obtaining the velocity-updated isotropic depth domain layer velocity model based on a pre-performed pre-stack time offset includes:

[0024] The root mean square initial velocity model in the time domain is obtained based on the pre-stack time offset.

[0025] The time-domain root mean square initial velocity model is converted and tomographic velocity inversion is performed to obtain an isotropic depth-domain layer velocity model.

[0026] This application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described in any of the preceding claims.

[0027] This application also provides a non-transitory computer-readable storage medium that stores computer instructions for causing a computer to perform any of the methods described above.

[0028] This application also provides a computer program product, including computer program instructions that, when run on a computer, cause the computer to perform the method described in any of the preceding claims. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic flowchart of the OVT domain VSP and ground seismic data depth joint imaging method according to an embodiment of this application;

[0031] Figure 2 This is a schematic diagram illustrating the principle of VSP and ground seismic OVT domain migration in an embodiment of this application;

[0032] Figure 3 This is a schematic diagram of ground seismic OVT gather sorting according to an embodiment of this application;

[0033] Figure 4This is a schematic diagram of the OVT division method for VSP data well-side imaging points according to an embodiment of this application;

[0034] Figure 5a This is a schematic diagram of the root mean square velocity model under the isotropic assumption of an embodiment of this application.

[0035] Figure 5b To Figure 5a A schematic diagram of the initial layer velocity model obtained after conversion;

[0036] Figure 5c To Figure 5b A schematic diagram of the iterative layer velocity model obtained by performing tomographic velocity inversion;

[0037] Figure 6 This is a schematic diagram of the VSP data OVT partitioning method according to an embodiment of this application;

[0038] Figure 7a This is the OVT domain well-to-surface combined depth domain gather before azimuth anisotropy correction in this application embodiment;

[0039] Figure 7b This is the OVT domain well-to-surface combined depth domain gather after azimuth anisotropy correction in this application embodiment;

[0040] Figure 8a This is a schematic diagram of a certain azimuth layer velocity model in an embodiment of this application before azimuth anisotropy correction.

[0041] Figure 8b This is a schematic diagram of a certain azimuth layer velocity model after azimuth anisotropy correction according to an embodiment of this application.

[0042] Figure 9 This is a schematic diagram of an OVT depth domain imaging profile combined with ground seismic well-to-surface analysis according to an embodiment of this application.

[0043] Figure 10 This is another schematic diagram of the OVT depth domain imaging profile combined with ground seismic well-to-surface analysis according to an embodiment of this application;

[0044] Figure 11 This is a spectral comparison diagram of the ground seismic profile and the combined imaging profile in the depth range of 1600m to 6000m, according to an embodiment of this application.

[0045] Figure 12 This is another schematic diagram of the OVT domain VSP and ground seismic data depth joint imaging method according to an embodiment of this application;

[0046] Figure 13 This is a schematic diagram of an electronic device according to an embodiment of this application. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0048] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0049] In related technologies, VSP data is typically used to assist surface seismic data in migration imaging and seismic interpretation, or the two types of data are processed separately and then stitched together. There are few cases of using combined well-to-surface data migration imaging. Even in cases where well-to-surface data migration imaging is used simultaneously, the impact of azimuth anisotropy on the imaging results is not considered. 3D-VSP, due to its acquisition method, contains rich azimuth information about subsurface structures; neglecting azimuth anisotropy would result in the waste of this information. Therefore, current methods combining 3D VSP data and surface seismic data suffer from insufficient imaging accuracy (insufficient resolution).

[0050] Based on this, this application provides a method for joint imaging of OVT (Offset Vector Tile) domain VSP and surface seismic data in the depth domain. First, the preprocessed VSP and surface seismic data are sorted using OVT gathers based on the shot-to-image point azimuth and shot-to-receiver azimuth, respectively. The gathers from the VSP and surface seismic OVT domains are then processed for azimuth sector consistency, amplitude consistency, and reference plane consistency. Next, pre-stack depth migration is performed simultaneously using the gathers from both OVT domains. The joint imaging gathers in the OVT domain are then corrected for azimuth anisotropy using the residual curvature method, and the layer velocity models in each azimuth are updated, ultimately yielding the joint well-to-surface depth domain imaging results. The imaging results improve the characterization accuracy of complex structures such as thin interbedded layers and small fault blocks, providing technical support for the exploration and development of complex oil and gas reservoirs.

[0051] Please see Figure 1 and Figure 12This application provides a method for joint depth imaging of OVT domain VSP and ground seismic data, the method comprising:

[0052] S100, acquires 3D VSP data and ground seismic data;

[0053] S200, perform a first preprocessing on the 3D VSP data to obtain first 3D VSP data; perform a second preprocessing on the ground seismic data to obtain first ground seismic data;

[0054] S300, perform a first partitioning process on the first 3D VSP data to obtain gather data of the 3D VSP OVT domain in multiple azimuth angles; perform a second partitioning process on the first ground seismic data to obtain gather data of the ground seismic OVT domain in multiple azimuth angle intervals;

[0055] S400, the gather data of the 3D VSP OVT domain and the gather data of the ground seismic OVT domain are corrected to obtain corrected gather data of the 3D VSP OVT domain and corrected gather data of the ground seismic OVT domain; the reference plane, amplitude magnitude and azimuth sector of the corrected gather data of the 3D VSP OVT domain and the corrected gather data of the ground seismic OVT domain are the same.

[0056] S500, based on the pre-stack time offset, obtains the velocity model of the isotropic depth domain layer after velocity update;

[0057] S600, based on the aforementioned isotropic depth domain layer velocity model, calculate the initial offset of the OVT domain joint pre-stack depth migration of the corrected 3D VSP OVT domain gather data and the corrected ground seismic OVT domain gather data at the imaging point, and obtain the initial OVT domain well-to-surface joint depth domain imaging gather.

[0058] S700, calculate the velocity update amount of multiple azimuth intervals based on the residual curvature method to obtain the average velocity model update amount of the azimuth interval; apply the average velocity model update amount to the initial depth domain layer velocity model according to the azimuth and perform iterative offset to obtain the OVT domain well-ground joint depth domain imaging gather after azimuth anisotropy correction.

[0059] S800, based on the OVT domain well-to-surface combined depth domain imaging gather after azimuth anisotropy correction, an OVT domain well-to-surface combined depth domain imaging profile is obtained.

[0060] The method in this application provides a method for joint pre-stack depth migration of VSP and ground seismic data OVT domain well-to-surface data; it also provides a method for correcting the azimuth anisotropy of well-to-surface imaging gathers, so that the phase axis of the joint imaging gathers can be correctly aligned and the influence of azimuth anisotropy on imaging can be eliminated, thereby achieving high-resolution, wide-coverage joint imaging of VSP and ground seismic OVT.

[0061] In some embodiments, in step S100, 3D VSP data can be acquired from a VSP observation system. Typically, the acquired 3D VSP data contains rich information on the azimuth of subsurface structures. Surface seismic data can be acquired from a surface seismic observation system. The 3D VSP data is typically corrected to a fixed reference surface at the wellhead, while the surface seismic data is typically corrected to a certain elevation.

[0062] In some of these embodiments, such as Figure 2 As shown, under the ground-based seismic observation system, seismic waves are excited by the source S, scattered at the imaging point O, and propagate through isotropic strata to the receiver R. The propagation time along the SOR path is t. G (α), Where v d (α) and v u (α) represents the down-going wave velocity and up-going wave velocity, respectively, as a function of the shot-receiver azimuth angle α; x d x u z and z are the distances of SC, CR and CO, respectively; C is the projection of O onto the surface.

[0063] In some of these embodiments, reference continues. Figure 2 Unlike surface seismic systems, VSP (Voice over Space) observation systems have their detectors installed in wells. The wave propagation path of a VSP is as follows: Figure 2 As shown in SOR0, when 3D VSP downlink waves from different azimuths propagate to the same imaging point O, the wave propagation path changes with the azimuth angle between the shot point and the imaging point, resulting in azimuth anisotropy of the downlink wave velocity. This differs from the velocity azimuth anisotropy caused by changes in shot-receiver azimuth in ground seismic data. However, the uplink wave path OR0 is fixed in the vertical plane between the imaging point and the receiver point, therefore the uplink wave travel time does not exhibit azimuth anisotropy. Based on the uplink wave propagation time formula and the characteristics of downlink waves, the propagation time of the downlink wave VSP data in each azimuth is determined as follows: in For the propagation time along S1OR0, As the azimuth of the seismic source-imaging point The changing downward wave speed, Z R For the receiver R0 and its surface projection point R w The vertical distance between them, x' d and x'u S1C and CR respectively w The distance.

[0064] In some embodiments, step S200, the first preprocessing of the 3D VSP data may include: performing RT rotation, wavefield separation, and static correction on the 3D VSP data, and then extracting the amplitude-preserving uplink PP wavefield. The second preprocessing of the ground seismic data may include amplitude compensation and multiple suppression on the ground seismic data to obtain pre-processed ground seismic data. Then, the wavelets from the aforementioned pre-processed 3D VSP data are applied to the pre-processed ground seismic data to improve its resolution, thus obtaining the first ground seismic data.

[0065] In some embodiments, in step S300, the first 3D VSP data can be subjected to OVT gather sorting based on shot-to-receiver azimuth and offset (i.e., first segmentation processing) to obtain gather data in the 3D VSP OVT domain with multiple azimuth angles. Typically, the gather data in the 3D VSP OVT domain has azimuth information, for example, it may have four azimuth intervals. The first ground seismic data can be subjected to OVT gather sorting based on shot-to-receiver azimuth and offset (i.e., second segmentation processing) to obtain gather data in the ground seismic OVT domain with multiple azimuth angles. Typically, the gather data in the ground seismic OVT domain has azimuth information, for example, it may have finer offset and azimuth angles compared to the gather data in the 3D VSP OVT domain.

[0066] In some embodiments, performing a first segmentation process on the first 3D VSP data may include: dividing the shot gather range separately according to the azimuth angle between the shot point and the image point, with each imaging point as the origin. The resulting segmentation can serve as the basis for subsequent azimuth-shifting of the VSP data. Specifically, as... Figure 3 As shown, the first 3D VSP data can be divided into four 45° azimuth sectors, including the diagonal sectors (i.e., each azimuth sector and the diagonal sector are of the same azimuth). The intersection of all sectors is the imaging point (see [reference]). Figure 3 (The yellow triangle in the image) Data within the same sector is considered to have the same azimuth. In this way, by dividing the first 3DVSP data into shot gather ranges separately according to the azimuth of the shot point and the image point, with each imaging point as the origin, the azimuth anisotropy of the formation can be reflected compared to shot-receiver azimuth sorting (because the 3DVSP detector is vertically fixed in the well, the shot-receiver azimuth and offset are very uniform and cannot reflect azimuth anisotropy), resulting in good quality of each azimuth imaging gather after offset.

[0067] In some embodiments, performing a second partitioning process on the first ground seismic data may include: performing a second partitioning process on the first ground seismic data based on the shot-receiver azimuth and offset. Specifically, as shown... Figure 4 The image shows the OVT (Out-of-Video) domain partitioning results for a set of orthogonal shot-receiver lines. Within an OVT domain of a set of orthogonal lines, there are almost identical shot-receiver azimuths and distances. By overlaying the surface cells at the same location along all orthogonal lines within the work area, the overlaid surface cells at that location theoretically contain all shot-receiver distances and azimuths. It can be understood that, theoretically, a shot-receiver azimuth can be found at every location throughout the entire work area; these surface cells constitute the OVT domain gather of the first surface seismic data for that azimuth.

[0068] In some embodiments, step S400 may include azimuth sector consistency correction. This azimuth sector consistency correction includes: firstly, aligning the imaging points of the 3D VSP OVT gather with the center points of the surface seismic OVT gathers; then, merging the azimuth sectors of the surface seismic OVT gathers with finer azimuth divisions according to the azimuth sector divisions of the 3D VSP OVT gathers, ensuring consistency in the azimuth sectors of the same imaging point (the center point of the surface seismic gathers), thus achieving accurate repositioning of data from different observation systems when offset in a unified depth domain coordinate system. This solves the problem of different offset distances and azimuth angles in the depth domain imaging gathers obtained from the different sorting methods of surface seismic OVT gathers and 3D VSP OVT gathers.

[0069] In some embodiments, the correction process may further include a reference plane consistency correction process. The reference planes of the 3D VSP OVT domain gather data and the surface seismic OVT domain gather data are typically not the same, exhibiting time differences at the same layer in the profile. Specifically, the 3D VSP OVT domain gather data is usually corrected to a fixed wellhead reference plane, while the surface seismic OVT domain gather data is typically corrected to a reference plane with a certain elevation. The reference plane consistency correction process can either correct the reference plane of the 3D VSP OVT domain gather data to match that of the surface seismic OVT domain gather data, or it can correct the reference plane of the surface seismic OVT domain gather data to match that of the 3D VSP OVT domain gather data. This allows for time difference correction between the 3D VSP OVT domain gather data and the surface seismic OVT domain gather data, ensuring that the reference planes of the 3D VSP OVT domain gather data and the surface seismic OVT domain gather data are matched. In this context, correcting the reference surface of the surface seismic OVT domain gather data to the reference surface of the 3D VSP OVT domain gather data can be understood as correcting the reference surface of the surface seismic OVT domain gather data to the wellhead fixed reference surface.

[0070] In some embodiments, step S500, calculating the offset of the joint pre-stack depth migration of the corrected 3D VSP OVT domain gather data and the corrected ground seismic OVT domain gather data at the imaging point may include:

[0071] Through Calculate the pre-stack depth migration (PSM) at the imaging point using the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data (i.e., the PSM at the imaging point X). i (the offset). Where, W G (X i ,X s ,X r ) is a weighting function for surface seismic data (e.g., corrected surface seismic OVT domain gather data). Where X s X i X r This represents the three-dimensional spatial location of the seismic source, imaging point, and ground detector. t is the propagation time. v is the wave velocity. α is the source-receiver azimuth. θ is the seismic wave incident angle. G (α) is the differential form of the minimum travel time ray tracing of ground seismic azimuth that varies with the shot-receiver azimuth. This refers to ground (surface) seismic data (e.g., gather data from the corrected surface seismic OVT domain). ds is the differential length along the ray path.

[0072] Among them, W V (X i ,X s ,X V X is a weighting function for 3D VSP data (e.g., gather data from the corrected 3D VSP OVT domain). s X i These are the data for the seismic source and the imaging point, respectively. X V This indicates the location of the 3D VSP detector. t is the propagation time. v is the wave speed. γ is the azimuth angle between the source and the imaging point, and γ is the angle between the direction of the reflected wave propagation and the wellbore. For 3DVSP data (e.g., gather data of the corrected 3D VSP OVT domain). ds is the differential of the minimum travel time ray tracing of the VSP. ds is the differential length along the ray path.

[0073] In some embodiments, step S600, obtaining the velocity-updated isotropic depth domain layer velocity model based on a pre-performed pre-stack time offset, includes:

[0074] The root mean square initial velocity model in the time domain is obtained based on previous work (such as pre-stack time migration).

[0075] The time-domain root mean square initial velocity model is converted and tomographic velocity inversion is performed to obtain an isotropic depth-domain layer velocity model.

[0076] Typically, after obtaining the isotropic depth domain layer velocity model, Kirchhoff depth migration can be performed to generate an initial depth domain imaging profile (i.e., the initial OVT domain well-to-surface combined depth domain imaging gather).

[0077] In some embodiments, in step S700, the OVT imaging gather can be pre-divided into multiple azimuth intervals, for example, each azimuth interval is 45°. This avoids the problem of directly using the velocity update values ​​in each azimuth to perform ellipse fitting, obtaining azimuth anisotropy parameters, and then using the azimuth anisotropy parameters to constrain the velocity in different azimuths. Under conditions with complex underground structures, this method cannot completely fit the ellipse model, thus amplifying the error.

[0078] The calculation of velocity updates for multiple azimuth intervals based on the residual curvature method may include: for each azimuth interval, using the formula z(h,η)=z0(η)+a(η)h 2 (That is, a quadratic polynomial) fits the residual time difference curve; where z0(η) is the theoretical depth of zero offset in the azimuth interval η, and a(η) is the curvature parameter of the azimuth interval, which is used for the azimuth anisotropy error of the reaction velocity model.

[0079] The velocity update for each azimuth interval can be calculated using the azimuth interval curvature parameter a(η), for example, through the formula... Calculate the velocity update for each azimuth angle interval. Where v0(x) i ) represents the isotropic velocity, h max This represents the maximum offset of the imaging gather.

[0080] In this way, by calculating the velocity update using the residual curvature method for each azimuth interval, and applying the updated velocity to the new migration, the azimuth anisotropy of velocity in each azimuth interval is corrected. This fully considers the azimuth anisotropy of velocity at the same depth due to the fact that the formation is usually not perfectly horizontal. It avoids directly superimposing data without correcting the azimuth anisotropy, which would lead to incomplete elimination of residual time differences in each azimuth caused by the azimuth anisotropy, resulting in reduced focus and resolution of the profile.

[0081] Example 1: Generation and Iteration of the Velocity Model

[0082] First, the well-to-surface data is preprocessed, including noise reduction, RT rotation, and vector wave field separation. Then, amplitude consistency processing is performed on the well-to-surface data to ensure that the amplitudes of the two datasets are on the same order of magnitude.

[0083] Then, a pre-stack time migration is performed to obtain the root mean square velocity model under the isotropic assumption (e.g.) Figure 5a After conversion, the initial layer velocity model is obtained (e.g.) Figure 5b The initial layer velocity model is subjected to tomographic velocity inversion to obtain the iterative layer velocity model. Figure 5c The accuracy of this model is significantly improved compared to the initial model.

[0084] Example 2: OVT gather sorting

[0085] OVT collection sorting of VSP data, such as Figure 6 As shown, with the Inline direction as 0° and counterclockwise rotation as the direction of increasing angle, and 45° intervals for azimuth, the system is divided into four main azimuth zones: Region I to Region IV (I: -22.5° to 22.5° and its diagonal azimuth; II: 22.5° to 67.5° and its diagonal azimuth; III: 67.5° to 112.5° and its diagonal azimuth; IV: 112.5° to 157.5° and its diagonal azimuth). The intersection of each azimuth zone marks the location of the imaging point, as shown below. Figure 4 As shown. The imaging point spacing is 25m. The preset imaging gather offset range is 0-5000m, and the offset interval is 50m.

[0086] For ground seismic data, OVT gather sorting is performed using mainstream industry methods based on the aforementioned theory.

[0087] Example 3: Generation and Azimuth Anisotropy Correction of OVT Joint Imaging Gathers

[0088] An initial OVT domain well-to-surface combined depth domain imaging gather is generated using a more accurate layer velocity model obtained from tomographic inversion, such as... Figure 7a As shown, "jitter" can be seen in the in-phase axis of the gather, which is caused by travel time calculation errors in each direction due to velocity azimuth anisotropy. The residual curvature method is used to pick up the time difference on the gather, and the layer velocity model in each direction is updated. The OVT domain pre-stack depth migration is then performed again using the velocity model including the azimuth velocity update, resulting in the azimuth anisotropy-corrected OVT domain well-to-surface combined depth domain imaging gather, as shown. Figure 7b As shown.

[0089] Comparing the velocity models before and after the update at a specific location, we can see that the velocity changes slightly after the update. The updated velocity model ( Figure 8b Compared to the previous version () Figure 8a (It has more details.)

[0090] Example 4: OVT Combined Depth Domain Imaging Effect

[0091] Figure 9 , Figure 10 A comparison was made between surface seismic profiles and well-to-surface migration profiles in the OVT domain. The red dashed line indicates the range within which VSP data participated in the effective migration during well-to-surface migration, and the same range is marked on the surface seismic profiles for comparison. It can be seen that, compared to surface seismic profiles, the OVT domain well-to-surface migration profiles exhibit better continuity of phase axes and improved resolution, as shown by the yellow arrows. The profiles show almost no stitching artifacts and a natural transition. The resolution and lateral continuity of the OVT domain well-to-surface migration profiles are improved compared to surface seismic profiles.

[0092] Comparison of the full imaging range (1600m–6000m) of the surface seismic profile in the OVT domain and the combined well-surface imaging profile in the OVT domain. Figure 11 The blue and green curves represent the spectral curves of surface seismic and OVT-domain well-surface combined depth domain imaging profiles, respectively. It can be seen that the dominant frequency of the OVT-domain well-surface combined depth domain imaging profile is slightly increased, the frequency band is significantly broadened, and the high-frequency portion is greatly enhanced, indicating that well-surface combined polarization has a greater advantage than traditional surface seismic processing methods in terms of detailed stratigraphic characterization.

[0093] It should be noted that the method in this embodiment can be executed by a single device, such as a computer or server. The method can also be applied in a distributed scenario, where multiple devices cooperate to complete the task. In such a distributed scenario, one of these devices may execute only one or more steps of the method in this embodiment, and the multiple devices will interact with each other to complete the method described.

[0094] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0095] Based on the same inventive concept, corresponding to any of the above embodiments, this application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the OVT domain VSP and ground seismic data depth joint imaging method described in any of the above embodiments.

[0096] Figure 13 This embodiment illustrates a more specific hardware structure of an electronic device, which may include a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, memory 1020, input / output interface 1030, and communication interface 1040 are interconnected internally via the bus 1050.

[0097] The processor 1010 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0098] The memory 1020 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0099] The input / output interface 1030 is used to connect input / output modules to realize information input and output. Input / output modules can be configured as components within the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touchscreens, microphones, various sensors, etc., while output devices may include displays, speakers, vibrators, indicator lights, etc.

[0100] The communication interface 1040 is used to connect a communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0101] Bus 1050 includes a pathway for transmitting information between various components of the device, such as processor 1010, memory 1020, input / output interface 1030, and communication interface 1040.

[0102] It should be noted that although the above-described device only shows the processor 1010, memory 1020, input / output interface 1030, communication interface 1040, and bus 1050, in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the embodiments of this specification, and not necessarily all the components shown in the figures.

[0103] The electronic devices described above are used to implement the corresponding OVT domain VSP and ground seismic data depth joint imaging method in any of the foregoing embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0104] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this application also provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to execute the OVT domain VSP and ground seismic data depth joint imaging method as described in any of the above embodiments.

[0105] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0106] The computer instructions stored in the storage medium of the above embodiments are used to cause the computer to execute the OVT domain VSP and ground seismic data depth joint imaging method as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0107] Based on the same inventive concept, corresponding to the OVT domain VSP and ground seismic data depth co-imaging method described in any of the above embodiments, this disclosure also provides a computer program product, which includes computer program instructions. In some embodiments, the computer program instructions can be executed by one or more processors of a computer to cause the computer and / or the processor to execute the OVT domain VSP and ground seismic data depth co-imaging method. Corresponding to the execution entity for each step in each embodiment of the OVT domain VSP and ground seismic data depth co-imaging method, the processor executing the corresponding step can belong to the corresponding execution entity.

[0108] The computer program product of the above embodiments is used to enable the computer and / or the processor to execute the OVT domain VSP and ground seismic data depth joint imaging method as described in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0109] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0110] Additionally, to simplify the description and discussion, and to avoid obscuring the embodiments of this application, the well-known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided drawings. Furthermore, the apparatus may be shown in block diagram form to avoid obscuring the embodiments of this application, and this also takes into account the fact that the details of the implementation of these block diagram apparatuses are highly dependent on the platform on which the embodiments of this application will be implemented (i.e., these details should be fully understood by those skilled in the art). While specific details (e.g., circuits) have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that the embodiments of this application can be implemented without these specific details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0111] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0112] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A method for joint depth imaging of OVT domain VSP and ground seismic data, characterized in that, include: Acquire 3D VSP data and ground seismic data; The 3D VSP data is subjected to a first preprocessing step to obtain the first 3D VSP data; The ground seismic data is subjected to a second preprocessing step to obtain the first ground seismic data; The first 3D VSP data is subjected to a first partitioning process to obtain gather data of the 3D VSP OVT domain at multiple azimuth angles; the first ground seismic data is subjected to a second partitioning process to obtain gather data of the ground seismic OVT domain at multiple azimuth angles. The gather data in the 3D VSP OVT domain and the gather data in the ground seismic OVT domain are corrected to obtain corrected gather data in the 3D VSP OVT domain and corrected gather data in the ground seismic OVT domain. The reference plane, amplitude magnitude, and azimuth sector of the corrected gather data in the 3D VSP OVT domain and the corrected gather data in the ground seismic OVT domain are the same. Based on the pre-stack time offset, the velocity model of the isotropic depth domain layer after velocity update is obtained; Based on the isotropic depth domain layer velocity model, the initial offset of the OVT domain joint pre-stack depth migration of the corrected 3D VSP OVT domain gather data and the corrected ground seismic OVT domain gather data at the imaging point is calculated to obtain the initial OVT domain well-to-surface joint depth domain imaging gather. The velocity update amount of multiple azimuth intervals is calculated based on the residual curvature method to obtain the average velocity model update amount of the azimuth interval; the average velocity model update amount is applied to the initial depth domain layer velocity model according to the azimuth and iteratively offset to obtain the OVT domain well-ground joint depth domain imaging gather after azimuth anisotropy correction. Based on the azimuth anisotropy-corrected OVT domain well-to-surface joint depth domain imaging gather, the OVT domain well-to-surface joint depth domain imaging profile is obtained.

2. The method for joint imaging of OVT domain VSP and ground seismic data depth according to claim 1, characterized in that, The first division process differs from the second division process; the correction process includes azimuth sector consistency correction process, reference plane consistency correction process, and amplitude consistency process. The azimuth sector consistency correction process includes: aligning the imaging points of the 3D VSP OVT domain gathers with the center points of the surface elements of the ground seismic OVT domain gathers; and merging the azimuth angles of the ground seismic OVT domain gathers according to the azimuth sector division of the 3D VSP OVT domain gathers, so that the azimuth sectors of the imaging points of the 3D VSP OVT domain gathers are consistent with the center points of the surface elements of the ground seismic OVT domain gathers. The reference plane consistency correction process includes correcting the reference plane of the 3D VSP OVT domain gather data and the reference plane of the ground seismic OVT domain gather data to the same reference plane.

3. The method for joint imaging of OVT domain VSP and ground seismic data depth according to claim 1, characterized in that, The calculation of the pre-stack depth migration at the imaging point, combining the corrected 3D VSP OVT domain gather data and the corrected ground seismic OVT domain gather data, includes: Through Calculate the pre-stack depth migration at the imaging point using the combined pre-stack depth migration of the corrected 3D VSP OVT domain gather data and the corrected ground seismic OVT domain gather data; where W G (X i ,X s ,X r X is the weighting function for gather data in the OVT domain of ground seismic earthquakes; s X i X r These represent the three-dimensional spatial locations of the seismic source, imaging point, and ground detector, respectively; d G (X s ,X r ,t G (α) represents ground seismic data; t G (α) represents the differential form of the minimum travel time ray tracing of a ground seismic event varying with the shot-receiver azimuth; α is the shot-receiver azimuth; ds is the differential length along the ray path; W V (X i ,X s ,X V ) is the weighting function for 3D VSP data; X V Position of the 3D VSP detector; For 3D VSP data; The derivative of the minimum travel time ray tracing for VSP; This represents the azimuth of the seismic source and the imaging point.

4. The method for joint imaging of OVT domain VSP and ground seismic data depth according to claim 3, characterized in that, θ is the incident angle of the seismic wave; t G (α)=t s +t r ; t is the propagation time; v is the wave speed; γ is the angle between the direction of the reflected wave propagation and the wellbore; 5. The method for joint imaging of OVT domain VSP and ground seismic data depth according to claim 1, characterized in that, The calculation of velocity updates for multiple azimuth intervals based on the residual curvature method includes: for each azimuth interval, using the formula z(h,η)=z0(η)+a(η)h 2 Fit the residual time difference curve; where z0(η) is the theoretical depth of zero offset in the azimuth interval η, and a(η) is the curvature parameter of the azimuth interval, used for the azimuth anisotropy error of the reaction velocity model; Through Calculate the velocity update in each azimuth angle interval; where v0(x i ) represents the isotropic velocity, h max This represents the maximum offset of the imaging gather.

6. The method for joint imaging of OVT domain VSP and ground seismic data depth according to claim 1, characterized in that, The first division process of the first 3D VSP data includes: dividing the shot collection range separately according to the azimuth angle of the shot point and the image point, with each imaging point as the origin.

7. The method for joint imaging of OVT domain VSP and ground seismic data depth according to claim 1, characterized in that, The process of obtaining the velocity-updated isotropic depth domain layer velocity model based on the pre-stack time offset includes: The root mean square initial velocity model in the time domain is obtained based on the pre-stack time offset. The time-domain root mean square initial velocity model is converted and tomographic velocity inversion is performed to obtain an isotropic depth-domain layer velocity model.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the method as claimed in any one of claims 1 to 7.

9. A non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method of any one of claims 1 to 7.

10. A computer program product comprising computer program instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1 to 7.

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