OVT domain VSP and ground seismic data depth joint imaging method and equipment

Abstract

The invention provides an OVT domain VSP and ground seismic data depth joint imaging method and related equipment. Comprising the following steps: acquiring 3D VSP data and ground seismic data; performing pretreatment; carrying out OVT gather division processing; carrying out consistency correction processing on a reference surface and a well location sector; obtaining an isotropic depth domain interval velocity model after velocity updating according to earlier-stage pre-stack time migration; calculating initial migration of OVT domain joint prestack depth migration at an imaging point according to an isotropic depth domain interval velocity model; calculating the speed update quantity of each azimuth angle interval based on a residual curvature method; applying the average velocity model update quantity to the isotropic depth domain interval velocity model according to the azimuth, and performing iterative migration to obtain an OVT domain well-ground joint depth domain imaging gather after azimuth anisotropy correction; and obtaining an OVT domain well-ground joint imaging profile based on the OVT domain well-ground joint depth domain imaging gather after azimuth anisotropy correction. And the description precision of complex structures such as thin interbeds and small fault blocks is improved.

Description

Technical Field

[0001] The present application relates to the field of seismic exploration technology, and in particular to a method and device for deep joint imaging of OVT domain VSP and ground seismic data. Background Art

[0002] 3D VSP (Vertical Seismic Profiling) data provides high vertical resolution and rich azimuthal anisotropy information, but its illumination range is limited to the area surrounding the wellbore. Compared to 3D VSP data, surface seismic data, while lower in resolution, provides a wider illumination range. Combined imaging of 3D VSP and surface seismic data allows for mutual constraints, combining the strengths of both data types. This makes it more suitable for imaging complex formations and azimuthal anisotropic media, meeting the growing demand 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 data sets separately and then stitching them together. However, the resulting imaging data suffers from insufficient accuracy. Summary of the Invention

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

[0005] Based on the above objectives, this application provides a method for deep joint imaging of OVT domain VSP and ground seismic data, including:

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

[0007] performing a first preprocessing on the 3D VSP data to obtain first 3D VSP data; performing a second preprocessing on the surface seismic data to obtain first surface seismic data;

[0008] Performing a first division process on the first 3D VSP data to obtain gather data in the 3D VSP OVT domain at multiple azimuth angles; the gather data in the 3D VSP OVT domain has azimuth information; performing a second division process on the first ground seismic data to obtain gather data in the ground seismic OVT domain at multiple azimuth angles; the gather data in the ground seismic OVT domain has azimuth information;

[0009] performing correction processing on the gather data in the 3D VSP OVT domain and the gather data in the surface seismic OVT domain to obtain corrected gather data in the 3D VSP OVT domain and corrected gather data in the surface seismic OVT domain; the reference plane and amplitude magnitude of the corrected gather data in the 3D VSP OVT domain and the corrected gather data in the surface seismic OVT domain are the same;

[0010] Based on the pre-stack time migration performed in advance, the isotropic depth domain layer velocity model with updated velocity is obtained;

[0011] Calculating the initial offset of the OVT domain joint prestack depth migration of the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data at the imaging point based on the isotropic depth domain layer velocity model to obtain an initial OVT domain well-surface joint depth domain imaging gather;

[0012] Velocity updates for multiple azimuth intervals are calculated based on the residual curvature method to obtain average velocity model updates for the azimuth intervals; the average velocity model updates are applied to the initial depth-domain layer velocity model according to azimuth, and iterative migration is performed to obtain OVT-domain well-ground joint depth-domain imaging gathers corrected for azimuth anisotropy;

[0013] Based on the OVT domain well-ground joint depth domain imaging gathers after the azimuth anisotropy correction, an OVT domain well-ground joint imaging profile is obtained.

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

[0015] The azimuth sector consistency correction process includes: aligning the imaging point of the 3D VSP OVT domain gather with the bin center point of the ground seismic OVT domain gather, and performing azimuth merging on the ground seismic OVT gather according to the azimuth sector division of the 3D VSP OVT domain gather, so that the azimuth sectors of the imaging point of the 3D VSP OVT domain gather and the bin center point of the ground seismic OVT domain gather are consistent;

[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 offset of the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data combined with prestack depth migration at the imaging point includes:

[0018] Pass-through Calculate the offset of the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data combined with prestack depth migration at the imaging point; wherein W G (X i ,X s ,X r ) is the weighting function of the surface seismic OVT domain gather data; X s 、X i 、X r are the three-dimensional spatial positions of the earthquake source, imaging point and ground detector respectively; d G (X s ,X r ,t G (α)) is the ground seismic data; t G (α) is the differential form of the minimum travel time ray tracing of ground earthquakes that varies with the shot detection azimuth; α is the shot detection azimuth; ds is the differential length along the ray path; W V (X i ,X s ,X V ) is the weighting function of 3D VSP data; X V is the position of the 3D VSP detector; It is 3D VSP data; is the differential of the minimum travel time ray tracing of VSP; is the source-imaging point azimuth.

[0019] In some 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 the velocity update amount 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 Fitting the residual moveout curve; where z0(η) is the zero-offset theoretical depth of the azimuth interval η, and a(η) is the curvature parameter of the azimuth interval, which is used to reflect the azimuthal anisotropy error of the velocity model;

[0021] Pass-through Calculate the velocity update amount for each azimuth interval; where v0(x i ) is the isotropic velocity, h max is the maximum offset of the imaging gather.

[0022] In some embodiments, the first division processing of the first 3D VSP data includes: taking each imaging point as an origin and dividing the shot gather range according to the source-imaging point azimuth.

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

[0024] The time domain RMS initial velocity model is obtained based on the pre-stack time migration performed in advance;

[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] An embodiment of the present application further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any of the above methods when executing the program.

[0027] An embodiment of the present application further provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute any of the methods described above.

[0028] An embodiment of the present application further provides a computer program product, comprising computer program instructions, which, when executed on a computer, causes the computer to execute any of the methods described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 Schematic diagram of the process of the deep joint imaging method of OVT domain VSP and ground seismic data according to an embodiment of the present application;

[0031] Figure 2 Schematic diagram of the VSP and ground seismic OVT domain migration principle of the embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of ground seismic OVT gather sorting in an embodiment of the present application;

[0033] Figure 4Schematic diagram of the OVT division method of the VSP data wellside imaging point according to an embodiment of the present application;

[0034] Figure 5a Schematic diagram of the root mean square velocity model under the isotropy assumption of an embodiment of the present application;

[0035] Figure 5b For Figure 5a Schematic diagram of the initial layer velocity model obtained after conversion;

[0036] Figure 5c For Figure 5b Schematic diagram of the iterative layer velocity model obtained by tomographic velocity inversion;

[0037] Figure 6 Schematic diagram of the VSP data OVT partitioning method according to an embodiment of the present application;

[0038] Figure 7a This is the OVT domain well-ground joint depth domain gather before azimuthal anisotropy correction in the embodiment of the present application;

[0039] Figure 7b This is the OVT domain well-ground joint depth domain gather after azimuthal anisotropy correction in the embodiment of the present application;

[0040] Figure 8a This is a schematic diagram of a certain azimuthal layer velocity model before azimuthal anisotropy correction according to an embodiment of the present application;

[0041] Figure 8b This is a schematic diagram of a velocity model of a certain azimuthal layer after azimuthal anisotropy correction according to an embodiment of the present application;

[0042] Figure 9 A schematic diagram of the combination of OVT depth domain imaging profile and surface seismic well-ground according to an embodiment of the present application;

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

[0044] Figure 11 A spectrum comparison diagram of the ground seismic profile and the joint imaging profile in the depth range of 1600m to 6000m in the embodiment of the present application;

[0045] Figure 12 Schematic diagram of another process of the method for deep joint imaging of OVT domain VSP and ground seismic data according to an embodiment of the present application;

[0046] Figure 13 This is a schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0048] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like 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 often used to assist surface seismic data in migration imaging and seismic interpretation, or both data types are processed and imaged separately before being spliced together. Few cases have combined well-surface data for migration imaging. Even in cases where well-surface data is used for migration imaging, the impact of azimuthal anisotropy on imaging is not considered. However, due to the unique nature of its acquisition method, 3D-VSP contains rich azimuthal information on subsurface structures. Failure to consider azimuthal anisotropy results in the waste of this information. Therefore, current methods for combining 3D VSP data with surface seismic data suffer from insufficient imaging accuracy (low resolution).

[0050] Based on this, the present invention provides a method for joint imaging of OVT (Offset Vector Tile) domain VSP and surface seismic data in the depth domain. First, the pre-processed VSP and surface seismic data are sorted based on the shot-imaging point azimuth and shot-receiver point azimuth, respectively, using OVT gathers. The VSP and surface seismic gathers in the OVT domain are processed for azimuth sector consistency, amplitude consistency, and datum consistency. Then, the gathers in the two OVT domains are used to simultaneously perform OVT domain prestack depth migration. The OVT domain joint imaging gathers are corrected for azimuth anisotropy using the residual curvature method, and the velocity models of each azimuth layer are updated, ultimately obtaining joint well-ground depth domain imaging results. The imaging results improve the accuracy of depicting complex structures such as thin interbeds and small fault blocks, providing certain technical support for the exploration and development of complex oil and gas reservoirs.

[0051] See also Figure 1 and Figure 12, an embodiment of the present application provides a method for deep joint imaging of OVT domain VSP and ground seismic data, the method comprising:

[0052] S100, acquiring 3D VSP data and surface seismic data;

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

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

[0055] S400, performing correction processing on the gather data in the 3D VSP OVT domain and the gather data in the surface seismic OVT domain to obtain corrected gather data in the 3D VSP OVT domain and corrected gather data in the surface 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 surface seismic OVT domain are the same;

[0056] S500, obtaining an isotropic depth-domain layer velocity model after velocity update based on pre-stack time migration performed in advance;

[0057] S600, calculating the initial offset of the OVT-domain joint prestack depth migration of the corrected 3D VSP OVT-domain gather data and the corrected surface seismic OVT-domain gather data at the imaging point based on the aforementioned isotropic depth-domain interval velocity model, to obtain an initial OVT-domain well-surface joint depth-domain imaging gather;

[0058] S700, calculating velocity updates for multiple azimuth intervals based on a residual curvature method to obtain average velocity model updates for the azimuth intervals; applying the average velocity model updates to an initial depth-domain layer velocity model according to azimuth, and performing iterative migration to obtain an OVT-domain well-ground joint depth-domain imaging gather corrected for azimuth anisotropy;

[0059] S800: Obtain an OVT-domain well-ground joint depth-domain imaging profile based on the OVT-domain well-ground joint depth-domain imaging gathers after the azimuthal anisotropy correction.

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

[0061] In some embodiments, in step S100, 3D VSP data may be acquired in a VSP observation system. The acquired 3D VSP data typically contains rich information about the location of underground structures. Ground seismic data may be acquired in a ground seismic observation system. The 3D VSP data is typically calibrated to a fixed wellhead datum. Ground seismic data is typically calibrated to a certain altitude.

[0062] In some embodiments, such as Figure 2 As shown in the ground seismic observation system, the seismic wave is excited by the source S, scattered at the imaging point O, and propagated in the isotropic formation to the receiver R. The propagation time along the SOR path is t G (α), where v d (α) and v u (α) are the downgoing wave velocity and upgoing wave velocity respectively, which vary with the gun detection azimuth angle α; x d 、x u and z are the distances of SC, CR and CO respectively; C is the projection of O on the surface.

[0063] In some of these embodiments, continue to refer to Figure 2 ,The VSP observation system is different from the surface seismic observation system, its geophone is placed in the well, and the wave propagation path of VSP is as follows Figure 2 As shown in Figure 1, the SOR0 of the upgoing wave is shown. When 3D VSP downgoing waves from different azimuths propagate to the same imaging point O, the wave propagation path changes with the azimuth between the shot point and the imaging point, resulting in azimuthal anisotropy of the downgoing wave velocity. This is different from the azimuthal anisotropy of velocity caused by changes in the shot-detection azimuth in surface seismic data. However, the upgoing wave path OR0 is fixed in the perpendicular plane between the imaging point and the detector point, so the upgoing wave travel time has no azimuthal anisotropy. Based on the propagation time formula of the upgoing wave and the characteristics of the downgoing wave, the propagation time of the downgoing wave VSP data at each azimuth is determined: in is the propagation time along S1OR0, is the azimuth angle of the source-imaging point Varying down-wave speed, Z R is the receiver R0 and its surface projection point R w The vertical distance between d and x'u S1C and CR respectively w distance.

[0064] In some embodiments, in 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 an amplitude-preserving vector uplink PP wavefield. The second preprocessing of the surface seismic data may include performing amplitude compensation and multiple suppression on the surface seismic data to obtain preliminary preprocessed surface seismic data, and then applying the wavelet from the preprocessed 3D VSP data to the preliminary preprocessed surface seismic data to improve the resolution of the surface seismic data, thereby obtaining first surface seismic data.

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

[0066] In some embodiments, performing a first segmentation process on the first 3D VSP data may include: taking each imaging point as the origin and segmenting the shot gather range according to the shot point-imaging point azimuth. The segmentation result may serve as the basis for performing azimuth migration on subsequent VSP data. Specifically, Figure 3 As shown, the first 3D VSP data can be divided into four 45° azimuth sectors, including the diagonal sector (ie, each azimuth sector and the diagonal sector are the same azimuth sector). The intersection of all sectors is the imaging point (see Figure 3 (yellow triangles in the image above). Data within the same sector is considered to have the same azimuth. Thus, by dividing the first 3DVSP data into shot gathers based on the shot-to-image point azimuth, with each imaging point as the origin, this method can better reflect the azimuthal anisotropy of the formation compared to sorting by shot-check azimuth (because 3DVSP receivers are fixed vertically in the well, the shot-check azimuth and offset distance are very simple and cannot reflect azimuthal anisotropy). This ensures that the migrated azimuthal imaging gathers have good quality.

[0067] In some embodiments, performing the second segmentation process on the first surface seismic data may include: performing the second segmentation process on the first surface seismic data according to the shot detection azimuth and the offset. Figure 4 Figure 2 shows the OVT domain partitioning results for a set of orthogonal shot detection lines. Within an OVT domain, each set of orthogonal lines has nearly identical shot detection azimuths and offsets. By overlaying bins at the same position across all orthogonal lines within the work area, the overlaid bins at that position theoretically possess all the offsets and shot detection azimuths. It can be understood that a bin for a shot detection azimuth can theoretically be found at every location throughout the work area. These bins constitute the OVT domain gather of the first surface seismic data for that azimuth.

[0068] In some embodiments, in step S400, the correction process may include azimuth sector consistency correction process. The azimuth sector consistency correction process includes: first aligning the imaging point of the 3D VSP OVT gather with the bin center point of the ground seismic OVT gather, merging the ground seismic OVT gather with a finer azimuth division according to the azimuth sector division of the 3D VSP OVT gather, so that the azimuth sectors of the same imaging point (for ground seismic, it is the bin center point) of the well-surface OVT gather are consistent, so as to achieve accurate positioning of data from different observation systems when offset in a unified depth domain coordinate system. In this way, the problem of different offsets and azimuths of the depth domain imaging gathers obtained by the offset between the ground seismic OVT domain gather sorting method and the 3D VSP OVT domain gather sorting method can be solved.

[0069] In some embodiments, the correction process may also include a datum consistency correction process. The datums of the gather data in the 3D VSPOVT domain and the gather data in the ground seismic OVT domain are usually not the same, and there is a time difference in the same layer on the profile. Among them, the gather data in the 3D VSP OVT domain is usually corrected to a fixed datum at the wellhead, while the gather data in the ground seismic OVT domain is usually corrected to a datum with a certain altitude. The datum consistency correction process can correct the datum of the gather data in the 3D VSP OVT domain to the datum of the gather data in the ground seismic OVT domain; it can also correct the datum of the gather data in the ground seismic OVT domain to the datum of the gather data in the 3D VSP OVT domain, so that the time difference correction can be performed on the gather data in the 3D VSP OVT domain and the gather data in the ground seismic OVT domain, so that the datum of the gather data in the 3D VSP OVT domain and the gather data in the ground seismic OVT domain match. Correcting the datum plane of the surface seismic OVT domain gather data to the datum plane of the 3D VSP OVT domain gather data can be understood as correcting the datum plane of the surface seismic OVT domain gather data to the wellhead fixed datum plane.

[0070] In some embodiments, in step S500, calculating the offset of the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data combined with prestack depth migration at the imaging point may include:

[0071] Pass-through Calculate the offset of the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data combined with pre-stack depth migration at the imaging point (that is, the OVT domain well-ground combined pre-stack depth migration at the imaging point X i where W G (X i ,X s ,X r ) is the weighting function of the surface seismic data (such as the corrected surface seismic OVT domain gather data). s 、X i 、X r is the three-dimensional spatial position of the earthquake source, imaging point and ground detector. t is the propagation time. v is the wave velocity. α is the azimuth of the shot. θ is the incident angle of the seismic wave. G (α) is the differential form of the minimum travel time ray tracing of ground earthquakes that varies with the shot detection azimuth. is the ground (surface) seismic data (such as the corrected ground seismic OVT domain gather data). ds is the differential length along the ray path.

[0072] Among them, W V (X i ,X s ,X V ) is the weighting function of 3D VSP data (e.g., corrected 3D VSP OVT domain gather data). s 、X i are the earthquake source and imaging point data respectively. V is the position of the 3D VSP detector. t is the propagation time. v is the wave speed. is the azimuth between the source and the imaging point, and γ is the angle between the propagation direction of the reflected wave and the wellbore. is 3D VSP data (for example, corrected 3D VSP OVT domain gather data). 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, in step S600, obtaining the isotropic depth-domain layer velocity model after velocity update based on the pre-stack time migration performed previously includes:

[0074] The time domain RMS initial velocity model 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 interval velocity model, Kirchhoff depth migration can be performed to generate an initial depth-domain imaging profile (ie, the initial OVT-domain well-ground joint depth-domain imaging gather).

[0077] In some embodiments, in step S700, the OVT imaging gathers can be pre-divided into multiple azimuth intervals, for example, each 45° interval. This avoids the problem of directly using the velocity updates in each orientation to fit an ellipse, calculate azimuthal anisotropy parameters, and then use these azimuthal anisotropy parameters to constrain velocities in different orientations. This can lead to incomplete fitting of the ellipse model under complex underground structures, which can amplify errors.

[0078] The method of calculating the velocity update amount of 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 (i.e., a quadratic polynomial) fitting the residual moveout curve; where z0(η) is the theoretical zero-offset depth of the azimuth interval η, and a(η) is the curvature parameter of the azimuth interval, which is used to reflect the azimuthal anisotropy error of the velocity model;

[0079] The velocity update amount of each azimuth interval is calculated using the azimuth interval curvature parameter a(η), for example, the formula Calculate the velocity update value of each azimuth interval. i ) is the isotropic velocity, h max is the maximum offset of the imaging gather.

[0080] In this way, by calculating velocity updates for each azimuth interval using the residual curvature method and applying the updated velocities to the next migration, the azimuthal anisotropy of velocity in each azimuth interval is corrected. This fully accounts for the azimuthal anisotropy of velocity at the same depth, which occurs because strata are typically not completely horizontal. This avoids the problem of directly stacking data that has not been corrected for azimuthal anisotropy, which would result in incomplete elimination of the residual moveout in each azimuth caused by azimuthal anisotropy and a reduction in profile focus and resolution.

[0081] Example 1: Generation and iteration of velocity model

[0082] First, the well-ground data are preprocessed, including denoising, RT rotation, vector wavefield separation, etc. Then, the well-ground data amplitude consistency processing is performed to make the amplitudes of the two data at the same level.

[0083] Then prestack time migration is performed to obtain the RMS velocity model under the isotropy assumption (e.g. Figure 5a , convert it and get the initial layer velocity model (such as Figure 5b ). Perform tomographic velocity inversion on the initial layer velocity model to obtain the iterative layer velocity model ( Figure 5c ), the accuracy of this model is significantly improved compared with the initial model.

[0084] Example 2 OVT gather sorting

[0085] The OVT gathers of VSP data are sorted as follows: Figure 6 As shown in the figure, with the inline direction as 0°, counterclockwise rotation as the direction of increasing angle, and 45° as the azimuth interval, it is divided into four main azimuth intervals from 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 orientation is the imaging point position, as shown in the figure. Figure 4 As shown in the figure, 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 the mainstream method in the industry according to the above theory.

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

[0088] The more accurate interval velocity model obtained by tomographic inversion is used to generate the initial OVT domain well-ground joint depth domain imaging gathers, such as Figure 7a As shown. It can be seen that there is "jitter" in the event axis in the gather. This is the error in the calculation of travel time in each orientation caused by the velocity azimuth anisotropy. The residual curvature method is used to pick up the time difference on the gather, and the velocity model of each orientation layer is updated. The velocity model including the azimuth velocity update is used to re-perform the OVT domain pre-stack depth migration, and the OVT domain well-ground joint depth domain imaging gather after azimuth anisotropy correction is obtained, as shown below. Figure 7b shown.

[0089] Comparing the velocity models before and after the velocity update of a certain direction, we can see that the velocity changes slightly after the velocity update. The updated velocity model ( Figure 8b ) than before the update ( Figure 8a ) has more details.

[0090] Example 4 OVT combined with depth domain imaging effect

[0091] Figure 9 、 Figure 10 A comparison of an OVT domain surface seismic profile and an OVT domain well-to-ground migration profile is shown. The red dashed line indicates the effective migration range of the VSP data during well-to-ground migration. The same range is marked on the surface seismic profile for easy comparison. Compared to surface seismic data, the OVT domain well-to-ground migration profile exhibits better event continuity and improved resolution. As indicated by the yellow arrows, the profile exhibits virtually no splicing artifacts and a smooth transition. The OVT domain well-to-ground migration profile exhibits improved resolution and lateral continuity compared to the surface seismic profile.

[0092] Comparison of the full imaging range of 1600m to 6000m depth spectrum of the OVT domain surface seismic profile and the OVT domain well-ground joint depth domain imaging profile ( Figure 11 ), the blue and green curves are the frequency spectrum curves of surface seismic and OVT-domain well-ground combined depth-domain imaging profiles, respectively. It can be seen that the dominant frequency of the OVT-domain well-ground combined depth-domain imaging profile has slightly increased, the frequency band has significantly broadened, and the high-frequency portion has been significantly enhanced, indicating that well-ground combined depth-domain imaging has advantages over traditional surface seismic processing methods in fine-grained stratigraphic characterization.

[0093] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied in a distributed scenario and performed by multiple devices working together. In such a distributed scenario, one of the multiple devices may only perform one or more steps of the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the method.

[0094] It should be noted that the above description is limited to some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in an order different from that described in the above embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain 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-mentioned embodiments and methods, the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and runnable on the processor. When the processor executes the program, the OVT domain VSP and ground seismic data deep joint imaging method described in any of the above embodiments is implemented.

[0096] Figure 13 10 is a schematic diagram showing a more specific hardware structure of an electronic device provided in this embodiment. The device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are communicatively connected to each other within the device via the bus 1050.

[0097] The processor 1010 can be implemented using a general-purpose CPU (Central Processing Unit), a microprocessor, an 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 devices, dynamic storage devices, etc. The memory 1020 can store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through 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 implement information input and output. The input / output modules can be configured as components within the device (not shown in the figure) or can be externally connected to the device to provide corresponding functions. Input devices may include a keyboard, mouse, touch screen, microphone, various sensors, etc., and output devices may include a display, speaker, vibrator, indicator light, etc.

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

[0101] The bus 1050 comprises a path for transmitting information between the various components of the device (eg, the processor 1010 , the memory 1020 , the input / output interface 1030 , and the communication interface 1040 ).

[0102] It should be noted that although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040, and the bus 1050, in a specific implementation, the device may also include other components necessary for normal operation. In addition, it will be understood by those skilled in the art that the above device may only include the components necessary to implement the embodiments of this specification, and does not necessarily include all the components shown in the figure.

[0103] The electronic device of the above embodiment is used to implement the corresponding OVT domain VSP and ground seismic data deep joint imaging method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be repeated here.

[0104] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the OVT domain VSP and ground seismic data deep joint imaging method as described in any of the above embodiments.

[0105] The computer-readable media of this embodiment include permanent and non-permanent, removable and non-removable media that can be used to store information by any method or technology. The 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 technology, read-only compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0106] The computer instructions stored in the storage medium of the above embodiment are used to enable the computer to execute the OVT domain VSP and ground seismic data deep 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 method for deep joint imaging of OVT-domain VSP and surface seismic data described in any of the above embodiments, the present disclosure further provides a computer program product comprising 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 perform the method for deep joint imaging of OVT-domain VSP and surface seismic data. Corresponding to the execution entities corresponding to the steps in each embodiment of the method for deep joint imaging of OVT-domain VSP and surface seismic data, the processors executing the corresponding steps can belong to the corresponding execution entities.

[0108] The computer program product of the above embodiment is used to enable the computer and / or the processor to execute the OVT domain VSP and ground seismic data deep 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 illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. Within the scope of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0110] In addition, for simplicity of description and discussion, and in order not to make the embodiment of the application difficult to understand, the known power supply / ground connection with integrated circuit (IC) chip and other components may or may not be shown in the accompanying drawings provided. In addition, the device can be shown in the form of a block diagram to avoid making the embodiment of the application difficult to understand, and this also takes into account the following fact, that is, the details of the embodiment of these block diagram devices are highly dependent on the platform to be implemented in the embodiment of the application (that is, these details should be fully within the scope of understanding of those skilled in the art). When specific details (for example, circuit) are set forth to describe exemplary embodiments of the application, it will be apparent to those skilled in the art that the embodiment of the application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered to be illustrative rather than restrictive.

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

[0112] The embodiments of the present 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 the present application should be included in the scope of protection of this application.

Claims

1. A method for deep joint imaging of OVT domain VSP and ground seismic data, characterized in that: include: Acquire 3D VSP data and surface seismic data; performing a first preprocessing on the 3D VSP data to obtain first 3D VSP data; performing a second preprocessing on the surface seismic data to obtain first surface seismic data; Performing a first division process on the first 3D VSP data to obtain 3D VSP OVT domain gather data at multiple azimuth angles; performing a second division process on the first ground seismic data to obtain ground seismic OVT domain gather data at multiple azimuth angles; performing correction processing on the gather data in the 3D VSP OVT domain and the gather data in the surface seismic OVT domain to obtain corrected gather data in the 3D VSP OVT domain and corrected gather data in the surface 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 surface seismic OVT domain are the same; Based on the pre-stack time migration performed in advance, the isotropic depth domain layer velocity model with updated velocity is obtained; Calculating the initial offset of the OVT domain joint prestack depth migration of the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data at the imaging point based on the isotropic depth domain layer velocity model to obtain an initial OVT domain well-ground joint depth domain imaging gather; Velocity updates for multiple azimuth intervals are calculated based on the residual curvature method to obtain average velocity model updates for the azimuth intervals; the average velocity model updates are applied to the initial depth-domain layer velocity model according to azimuth, and iterative migration is performed to obtain OVT-domain well-ground joint depth-domain imaging gathers corrected for azimuth anisotropy; Based on the OVT domain well-ground joint depth domain imaging gathers after azimuth anisotropy correction, an OVT domain well-ground joint depth domain imaging profile is obtained.

2. The method for deep joint imaging of OVT domain VSP and surface seismic data according to claim 1, characterized in that: The first division process is different from the second division process; the correction process includes azimuth sector consistency correction process, reference plane consistency correction process and amplitude consistency correction process; The azimuth sector consistency correction process includes: aligning the imaging point of the 3D VSP OVT domain gather with the bin center point of the terrestrial seismic OVT domain gather, and merging the terrestrial seismic OVT domain gather in azimuth according to the azimuth sector division of the 3D VSP OVT domain gather, so that the azimuth sectors of the imaging point of the 3D VSP OVT domain gather and the bin center point of the terrestrial seismic OVT domain gather are consistent; 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 deep joint imaging of OVT domain VSP and surface seismic data according to claim 1, characterized in that: The calculating of the offset of the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data in combination with pre-stack depth migration at the imaging point comprises: Pass-through Calculate the offset of the corrected 3D VSP OVT domain gather data and the corrected surface seismic OVT domain gather data combined with prestack depth migration at the imaging point; wherein W G (X i ,X s ,X r ) is the weighting function of the surface seismic OVT domain gather data; X s 、X i 、X r are the three-dimensional spatial positions of the earthquake source, imaging point and ground detector respectively; d G (X s ,X r ,t G (α)) is the ground seismic data; t G (α) is the differential form of the minimum travel time ray tracing of ground earthquakes that varies with the shot detection azimuth; α is the shot detection azimuth; ds is the differential length along the ray path; W V (X i ,X s ,X V ) is the weighting function of 3D VSP data; X V is the position of the 3D VSP detector; It is 3D VSP data; is the differential of the minimum travel time ray tracing of VSP; is the source-imaging point azimuth.

4. The method for deep joint imaging of OVT domain VSP and surface seismic data according to claim 3, characterized in that: t is the propagation time; v is the wave speed; 5. The method for deep joint imaging of OVT domain VSP and surface seismic data according to claim 1, characterized in that: The method of calculating the velocity update amount of 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 Fitting the residual moveout curve; where z0(η) is the zero-offset theoretical depth of the azimuth interval η, and a(η) is the curvature parameter of the azimuth interval, which is used to reflect the azimuthal anisotropy error of the velocity model; Pass-through Calculate the velocity update amount for each azimuth interval; where v0(x i ) is the isotropic velocity, h max is the maximum offset of the imaging gather.

6. The method for deep joint imaging of OVT domain VSP and surface seismic data according to claim 1, characterized in that: The first division processing of the first 3D VSP data includes: taking each imaging point as an origin and dividing the shot gather range according to the shot point-imaging point azimuth angle.

7. The method for deep joint imaging of OVT domain VSP and surface seismic data according to claim 1, characterized in that: The method of obtaining an isotropic depth-domain layer velocity model after velocity update based on pre-stack time migration performed in advance includes: The time domain RMS initial velocity model is obtained based on the pre-stack time migration performed in advance; 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 implements the method according to any one of claims 1 to 7 when executing the program. 9 . A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the method according to claim 1 .

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

Images