Three-dimensional vsp pre-stack time migration imaging method and related device

Abstract

The present disclosure provides a three-dimensional VSP pre-stack time migration imaging method and related device, the method comprising: determining the original seismic data of three-dimensional VSP, performing depth calculation based on the original seismic data to obtain imaging point depth information; performing segmented travel time calculation on the imaging point depth information to obtain total travel time data; performing offset expansion based on the total travel time data to obtain VSP imaging gathers; performing velocity analysis on the VSP imaging gathers to obtain migration imaging results. The present disclosure can effectively solve the problem of complex imaging gather time-distance relationship caused by the non-symmetry of the observation system in VSP data processing, and through segmented travel time calculation and offset expansion, the VSP imaging gathers approximately satisfy the hyperbolic time-distance relationship, thereby improving the velocity analysis precision and imaging quality.

Description

Technical Field

[0001] This disclosure relates to the field of seismic exploration technology, and in particular to a three-dimensional VSP pre-stack time migration imaging method and related apparatus. Background Technology

[0002] This section is intended to provide background or context for the embodiments of this disclosure as set forth in the claims. The description herein is not intended to be a prior art simply because it is included in this section.

[0003] Vertical seismic profile (VSP) technology, by placing a geophone in the well, can obtain seismic records with high signal-to-noise ratio and high resolution, providing valuable subsurface information for oil and gas exploration. Pre-stack time migration imaging, on the other hand, is a seismic processing technique that directly performs time-shift correction and migration realignment on unstacked single-shot seismic records, which can accurately reconstruct complex subsurface structures and improve imaging accuracy.

[0004] However, in related technologies, the asymmetry of the VSP observation system causes the time-distance relationship of the imaging gathers to no longer satisfy a simple hyperbolic law, which makes it difficult to directly apply conventional velocity analysis methods, thus affecting the effectiveness of VSP data in velocity analysis and imaging accuracy. Summary of the Invention

[0005] In view of this, the purpose of this disclosure is to propose a three-dimensional VSP pre-stack time-migrating imaging method, which at least partially solves one of the technical problems in the related art.

[0006] To achieve the above objectives, a first aspect of the exemplary embodiments of this disclosure provides a three-dimensional VSP pre-stack time migration imaging method, the method comprising: The original seismic data of the 3D VSP is determined, and depth calculation is performed based on the original seismic data to obtain the depth information of the imaging points; The total travel time data is obtained by segmenting the depth information of the imaging points; Based on the total travel time data, the shot-receiver distance is extended to obtain the VSP imaging gather; Velocity analysis was performed on the VSP imaging gather to obtain the offset imaging results.

[0007] Based on the same inventive concept, a second aspect of the exemplary embodiments of this disclosure provides a three-dimensional VSP pre-stack time-migrating imaging apparatus, comprising: The depth information determination module is configured to determine the original seismic data of the three-dimensional VSP, perform depth calculation based on the original seismic data, and obtain the depth information of the imaging points. The travel time data determination module is configured to perform segmented travel time calculation on the depth information of the imaging point to obtain total travel time data; The imaging gather determination module is configured to perform shot-receiver distance expansion based on the total travel time data to obtain the VSP imaging gather; The imaging result determination module is configured to perform velocity analysis on the VSP imaging gather to obtain the offset imaging result.

[0008] Based on the same inventive concept, a third aspect of the exemplary embodiments of this disclosure 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 as described in the first aspect.

[0009] Based on the same inventive concept, a fourth aspect of the exemplary embodiments of this disclosure provides a non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method as described in the first aspect.

[0010] Based on the same inventive concept, a fifth aspect of the exemplary embodiments of this disclosure provides a computer program product including computer program instructions that, when run on a computer, cause the computer to perform the method as described in the first aspect.

[0011] As can be seen from the above description, the three-dimensional VSP pre-stack time migration imaging method and related apparatus provided in this disclosure include: This method involves determining the original seismic data of a 3D VSP (Vibration Spectroscopic Pool), performing depth calculations based on the original seismic data to obtain imaging point depth information, calculating segmented travel times on the imaging point depth information to obtain total travel time data, expanding the shot-receiver offset based on the total travel time data to obtain VSP imaging gathers, and performing velocity analysis on the VSP imaging gathers to obtain migration imaging results. This disclosure effectively solves the problem of complex time-distance relationships in imaging gathers caused by the asymmetry of the observation system in VSP data processing. By using segmented travel time calculations and shot-receiver offset expansion, the VSP imaging gathers approximately satisfy a hyperbolic time-distance relationship, thereby improving the accuracy of velocity analysis and imaging quality. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in this disclosure or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 A schematic diagram of an application scenario of the three-dimensional VSP pre-stack time migration imaging method provided as an exemplary embodiment of the present disclosure; Figure 2 A schematic flowchart of a three-dimensional VSP pre-stack time migration imaging method provided for an exemplary embodiment of the present disclosure; Figure 3 A schematic diagram of a VSP observation system and ray path for a three-dimensional VSP pre-stack time migration imaging method provided as an exemplary embodiment of the present disclosure; Figure 4 A schematic diagram of a three-dimensional VSP single-shot recording provided as an exemplary embodiment of the present disclosure; Figure 5 A schematic diagram of a VSP imaging gather for a three-dimensional VSP pre-stack time-migrating imaging method provided as an exemplary embodiment of the present disclosure; Figure 6 A schematic diagram of VSP imaging gather velocity analysis for a three-dimensional VSP pre-stack time migration imaging method provided as an exemplary embodiment of the present disclosure; Figure 7 A schematic diagram of a VSP pre-stack time migration imaging profile provided as an exemplary embodiment of the present disclosure; Figure 8 A schematic diagram of a three-dimensional VSP pre-stack time migration imaging method provided as an exemplary embodiment of the present disclosure; Figure 9 A schematic diagram of the structure of electronic device hardware provided by an exemplary embodiment of this disclosure. Detailed Implementation

[0014] It is understood that before using the technical solutions disclosed in the various embodiments of this application, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in this application in an appropriate manner in accordance with relevant laws and regulations, and user authorization should be obtained.

[0015] For example, upon receiving a user's active request, a prompt message is sent to the user to explicitly inform them that the requested operation will require the acquisition and use of the user's personal information. This allows the user to independently choose whether to provide personal information to the software or hardware, such as the electronic device, application, server, or storage medium performing the operations of this application's technical solution, based on the prompt message.

[0016] As an optional but non-limiting implementation, in response to a user's active request, sending a prompt message to the user can be done via a pop-up window, where the prompt message can be presented in text format. Furthermore, the pop-up window can also include a selection control allowing the user to choose "agree" or "disagree" to provide personal information to the electronic device.

[0017] It is understood that the above notification and user authorization process are merely illustrative and do not constitute a limitation on the implementation of this application. Other methods that comply with relevant laws and regulations may also be applied to the implementation of this application.

[0018] It is understood that the data involved in this technical solution (including but not limited to the data itself, the acquisition or use of the data) shall comply with the requirements of relevant laws, regulations and related provisions.

[0019] To make the objectives, technical solutions, and advantages of this disclosure clearer, the principles and spirit of this disclosure will be described below with reference to several exemplary embodiments. It should be understood that these embodiments are provided merely to enable those skilled in the art to better understand and implement this disclosure, and are not intended to limit the scope of this disclosure in any way. Rather, these embodiments are provided to make this disclosure more thorough and complete, and to fully convey the scope of this disclosure to those skilled in the art.

[0020] In this article, it is important to understand that any number of elements in the accompanying figures is for illustrative purposes and not for limitation, and any naming is for distinction only and has no limiting meaning.

[0021] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar words used in the embodiments of this disclosure 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 following 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 used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. The article "a" or "an" preceding an element does not exclude the existence of multiple such elements.

[0022] The principles and spirit of this disclosure will be explained in detail below with reference to several representative embodiments.

[0023] As described in the background section, the asymmetry of VSP (Vacuum-Sinking Space) observation systems means that the time-distance relationship of imaging gathers no longer follows a simple hyperbolic law. This makes it difficult to directly apply conventional velocity analysis methods, thus affecting the effectiveness of VSP data in velocity analysis and imaging accuracy. Specifically, with the widespread adoption of 3D VSP technology, how to fully utilize its rich wavefield information to achieve accurate imaging and parameter inversion has become a core research focus. Especially in the pre-stack time migration processing stage, obtaining imaging gathers that can be effectively used for velocity analysis is a crucial step in achieving accurate velocity modeling and subsequent geological interpretation.

[0024] Although velocity analysis techniques based on hyperbolic time-distance relationships have become very mature in traditional ground seismic data processing, the VSP observation system has significant asymmetry, which causes the time-distance relationship of its imaging gathers to no longer follow a simple hyperbolic law, thus resulting in an essential difference from ground seismic data.

[0025] This difference is specifically reflected in the definition of shot-receiver distance and the asymmetry of wave propagation paths. If conventional ground seismic velocity analysis methods are directly applied to VSP data, significant errors will be introduced, severely restricting the application effect and accuracy of VSP data in the field of velocity analysis.

[0026] To address the aforementioned issues, this disclosure provides a three-dimensional VSP pre-stack time migration imaging method and related apparatus, the method specifically including: The original seismic data of the 3D VSP is determined, and depth calculation is performed based on the original seismic data to obtain the depth information of the imaging points; the travel time of the imaging point depth information is segmented to obtain the total travel time data; the shot-receiver offset is extended based on the total travel time data to obtain the VSP imaging gather; the velocity analysis of the VSP imaging gather is performed to obtain the migration imaging results.

[0027] In this disclosure, during pre-stack time migration, for each input seismic trace within the migration aperture, the position of the geophone in the well is extended along the up-wave ray path to the surface to construct a virtual geophone point based on the location of the subsurface imaging point. Then, for different ray path segments of the VSP, segmented travel times are calculated using different root-mean-square velocities to obtain the actual travel time and the total travel time including the virtual ray segment travel time. Next, the actual shot-receiver offset is extended to the virtual shot-receiver offset, and the amplitude of the actual travel time on the VSP input seismic trace is mapped one by one to the corresponding total travel time sampling point. The amplitudes of all mapped points within the aperture at the imaging point are interferometrically superimposed to generate the VSP imaging gather. Finally, velocity analysis is performed on the VSP imaging gather to obtain the migration imaging results. The VSP migration imaging gather obtained by this disclosure approximately satisfies the hyperbolic time-distance relationship of surface seismic data, is applicable to conventional velocity analysis techniques, and strongly promotes the development of VSP data in velocity analysis and imaging techniques.

[0028] After introducing the basic principles of this disclosure, various non-limiting embodiments of this disclosure will be described in detail below.

[0029] refer to Figure 1 This is a schematic diagram of an application scenario of the three-dimensional VSP pre-stack time migration imaging method provided in the exemplary embodiments of this disclosure.

[0030] This application scenario includes a terminal device 101 and a server 102. The terminal device 101 and the server 102 can be connected via a wired or wireless communication network to achieve data interaction.

[0031] Terminal device 101 may be an electronic device located close to the user side, possessing data transmission and multimedia input / output functions, including but not limited to desktop computers, mobile phones, portable computers, tablet computers, media players, smart wearable devices, personal digital assistants (PDAs), or other electronic devices capable of performing the aforementioned functions. This electronic device may include a processor and a display screen with touch input functionality. The display screen is used to present a graphical user interface (GUI), which can display an application interface. The processor is used to process application data, generate the GUI, and control the display of the GUI on the screen.

[0032] Server 102 can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN (Content Delivery Network), and big data and artificial intelligence platforms.

[0033] In some exemplary embodiments, the three-dimensional VSP pre-stack time-lapse imaging method can be run on terminal device 101 or server 102.

[0034] When the three-dimensional VSP pre-stack time migration imaging method is running on server 102, server 102 is used to provide three-dimensional VSP pre-stack time migration imaging services to users of terminal device 101.

[0035] Server 102 determines the original seismic data of the three-dimensional VSP, and performs depth calculation based on the original seismic data to obtain the depth information of the imaging points; Server 102 performs segmented travel time calculations on the depth information of the imaging points to obtain total travel time data; Server 102 performs shot-receiver distance expansion based on the total travel time data to obtain VSP imaging gathers; After performing velocity analysis on the VSP imaging gather and obtaining the offset imaging results, the server 102 transmits the offset imaging results to the terminal device 101.

[0036] It should be noted that the above application scenarios are shown only to facilitate understanding of the spirit and principles of this disclosure, and the implementation of this disclosure is not limited in any way. On the contrary, the implementation of this disclosure can be applied to any applicable scenario.

[0037] refer to Figure 2 A three-dimensional VSP pre-stack time-migrating imaging method, the method comprising the following steps: Step S210: Determine the original seismic data of the three-dimensional VSP, and perform depth calculation based on the original seismic data to obtain the depth information of the imaging points.

[0038] In practice, raw seismic data refers to seismic signal data acquired through a 3D VSP observation system. This data records the wavefield information received by detectors placed in wells after seismic waves generated from surface shot points propagate underground. Specifically, it includes characteristic information such as the amplitude, phase, frequency, and arrival time of the seismic waves, reflecting the physical properties and geological structure of the subsurface medium.

[0039] In practice, the imaging point depth information refers to the specific depth value of the imaging point in the subsurface medium calculated point by point, based on the imaging grid constructed from the geometric parameters of the original 3D VSP seismic data, combined with the root mean square velocity field of the P-wave in the original seismic data and the horizontal position information of the imaging grid.

[0040] In some embodiments, depth calculation is performed based on the original seismic data to obtain imaging point depth information, including: An imaging grid is constructed based on the geometric parameters of the original seismic data. Depth calculation is performed based on the root mean square velocity field of the P-waves in the original seismic data and the horizontal position information of the imaging grid to obtain the depth information of the imaging point.

[0041] In practice, the imaging grid is constructed based on the geometric parameters of the original seismic data in the following manner: First, based on the geometric information recorded in the raw seismic data, such as the shot point locations, borehole geophone locations, and the distribution characteristics of imaging points, the extent and spatial layout of the imaging area are determined. Then, combining the sampling interval and coverage area of ​​the seismic data with the characteristics of the target geological body, grid cells with a certain spatial resolution are created. These grid cells cover the entire imaging area, forming a three-dimensional grid system. The horizontal position information of each grid cell will serve as the basis for subsequent depth calculations and migration imaging, used to accurately determine the location of imaging points in the subsurface medium.

[0042] In specific implementation, the depth information of the imaging point is obtained by performing depth calculation based on the root mean square velocity field of the P-wave in the original seismic data and the horizontal position information of the imaging grid: The depth information of the imaging points is calculated by combining the root mean square velocity field of the P-wave (PP wave) (i.e., the P-wave root mean square velocity field) from the raw 3D VSP seismic data with the horizontal position information of the imaging grid. Specifically, using the velocity information provided by the PP wave root mean square velocity field, combined with the horizontal position coordinates of each imaging point in the imaging grid, the depth value of each imaging point in the subsurface medium is calculated point by point according to the relationship between the propagation time and velocity of the seismic wave. This embodiment can combine the propagation characteristics of seismic waves with the spatial layout of the imaging grid, thereby accurately determining the depth position of each imaging point in three-dimensional space.

[0043] Step S220: Perform segmented travel time calculation on the depth information of the imaging points to obtain total travel time data.

[0044] In practice, the total travel time data refers to the complete propagation time of a seismic wave from the shot point, after being reflected by the imaging point, to the virtual surface receiver point, obtained by segmented travel time calculation.

[0045] In some embodiments, the imaging point depth information is segmented for travel time calculation to obtain total travel time data, including: The geometric distribution characteristics of the original seismic data are determined to define the aperture, thus obtaining the imaging migration aperture. Based on the imaging offset aperture and the imaging point depth information, the root mean square velocity information of the strata corresponding to each ray path segment is obtained; Segmented travel time calculations are performed based on each of the root mean square velocity information to obtain downwave travel time data, upwave travel time data and virtual travel time data; The total travel time data is obtained based on the downwave travel time data, the upwave travel time data, and the virtual travel time data.

[0046] In practice, the imaging migration aperture refers to a spatial range determined based on the geometric distribution characteristics of the original seismic data in the three-dimensional VSP pre-stack time migration process, which is used to limit the seismic trace data participating in the imaging calculation.

[0047] In practice, root mean square velocity information refers to the formation velocity parameters calculated for different ray path segments in three-dimensional VSP (vertical seismic profile) data. This velocity information is based on the depth information of imaging points within the imaging migration aperture, combined with the geometric features and velocity model of the original seismic data, to calculate the root mean square velocity values ​​for the downlink band, uplink band, and virtual uplink band, respectively.

[0048] In practice, the geometric distribution characteristics of the original seismic data are determined to define the aperture, resulting in the imaging migration aperture: Based on the spatial relationships between shot points, borehole geophones, and imaging points in the seismic data, and considering the geological structure and seismic wave propagation characteristics of the target imaging area, a reasonable spatial range, namely the imaging migration aperture, is determined. This aperture is used to limit the range of seismic trace data involved in the calculation during migration imaging, ensuring that only seismic traces spatially correlated with the target imaging points are included in the calculation. This avoids errors introduced by seismic traces that are too far away, improves imaging accuracy, and optimizes computational efficiency.

[0049] In specific implementation, the root mean square velocity information of the strata corresponding to each ray path segment is obtained based on the imaging offset aperture and the imaging point depth information as follows: First, the range of seismic traces involved in the calculation is determined using the imaging migration aperture. Combined with the depth information of the imaging points, the specific location of each imaging point in the subsurface medium is clarified. Then, based on the depth of these imaging points and the wavefield characteristics in the seismic data, the root mean square velocity of each ray path segment is calculated: from the shot point to the imaging point (downward band), from the imaging point to the borehole geophone (upward band), and from the borehole geophone to the virtual surface geophone point (virtual upward band).

[0050] In specific implementation, the following method is used to obtain downwave travel time data, upwave travel time data, and virtual travel time data by performing segmented travel time calculations based on each of the aforementioned root mean square velocity information: refer to Figure 3 Actual VSP ray travel time data It consists of two parts:

[0051] Downward wave travel time data is as follows:

[0052] in, This is the travel time data from the shot point to the underground imaging point, using the root mean square velocity of this stratum. ; The excitation point, located on the Earth's surface, is the source of seismic waves; its location is usually expressed using coordinates. This indicates that seismic waves propagate downwards from the shot point and enter the underground medium.

[0053] The travel time data for the upward wave is as follows:

[0054] in, This is the travel time data from the imaging point to the geophone section in the well, using the root mean square velocity of this formation section. ; It is the reflection point of the underground target, located at a certain point within the imaging area, and its position is represented by coordinates. The imaging point is the point where seismic waves are reflected after propagating from the shot point into the subsurface medium. This is a receiver point located within the well, used to receive seismic waves reflected from the imaging point. Its location is indicated by coordinates. To express.

[0055] An additional virtual travel time from the borehole geophone to the virtual geophone point is added to the actual VSP ray travel time to approximate the travel time formula for the hyperbolic surface seismic curve. The additional virtual travel time is:

[0056] in, This is the travel time data from the in-well geophone to the virtual geophone point on the surface, using the root mean square velocity of this formation segment. ; It is a virtual point located on the Earth's surface, used to convert seismic wave data received by the borehole geophone into a form similar to surface seismic data. Its location is indicated by coordinates. This indicates that, by introducing virtual receivers, the hyperbolic time-distance relationship of ground earthquakes can be approximately constructed.

[0057] In specific implementation, the total travel time data is obtained based on the downwave travel time data, the upwave travel time data, and the virtual travel time data in the following way: Total travel time data can be obtained using the following formula: .

[0058] Step S230: Based on the total travel time data, perform shot-receiver distance expansion to obtain VSP imaging gathers.

[0059] In practice, VSP imaging gathers refer to a set of seismic data records generated through three-dimensional VSP pre-stack time migration processing, which reflects the seismic wave reflection characteristics of underground imaging points under different shot-receiver distances.

[0060] In some embodiments, shot-receiver distance extension is performed based on the total travel time data to obtain VSP imaging gathers, including: The shot location information, borehole geophone location information, and virtual surface geophone location information of the original seismic data are determined. Based on the shot location information, borehole geophone location information, and virtual surface geophone location information, the extended shot-receiver distance information is obtained. Based on the total travel time data and the extended shot-receiver distance information, amplitude mapping and interferometric superposition are performed to obtain the VSP imaging gather.

[0061] In specific implementation, the shot location information, borehole geophone location information, and virtual surface geophone location information of the original seismic data are determined. Based on the shot location information, borehole geophone location information, and virtual surface geophone location information, the extended shot-receiver distance information is obtained in the following way: refer to Figure 3 Considering a three-dimensional VSP observation system, let the shot point location be... On the surface, the location of the detector in the well is... The location of the imaging point is The PP wave path is from the shot point S down to the imaging point P, and then from the imaging point P up to the geophone R in the well.

[0062] To obtain imaging gathers suitable for ground seismic velocity analysis, a virtual surface receiver needs to be constructed. The virtual travel time from R to the virtual detector R' is added to the actual travel time from imaging point P to the geophone R in the well. Simultaneously, the shot-detector distance is adjusted from the shot-well distance. Extended to the distance from the shot point to the virtual receiver point .

[0063] The actual shot-receiver distance is the horizontal distance from the shot point to the geophone in the well:

[0064] The extended shot-receiver distance is the horizontal distance from the shot point to the virtual receiver point:

[0065] The location of the virtual detector point R' needs to meet the following condition: the travel time of the straight ray from the imaging point P to R' should be equal to the travel time of the refracted ray from P to R and then to R', that is:

[0066] Among them, the extended shot-receiver distance information refers to the distance from the shot point to the virtual surface receiver point calculated through geometric relationships. This distance It is based on the actual shot-receiver distance. Extended from the original borehole spacing This is to convert VSP data into a format suitable for ground seismic velocity analysis.

[0067] In some embodiments, amplitude mapping and interferometric superposition are performed based on the total travel time data and the extended shot-receiver distance information to obtain the VSP imaging gather, including: Amplitude is extracted based on the downwave travel time data and the upwave travel time data to obtain the actual travel time amplitude data; The actual travel time amplitude data is mapped to each sampling point corresponding to the total travel time data, and the amplitude data of each sampling point is interferometrically superimposed based on the extended shot-receiver distance information to obtain the VSP imaging gather.

[0068] In specific implementation, the actual travel time amplitude data is obtained by extracting amplitude based on the downwave travel time data and the upwave travel time data as follows: Amplitude extraction based on downwave and upwave travel time data involves analyzing waveform characteristics in the seismic trace to identify reflected wave signals associated with the imaging point and extracting the corresponding amplitude values. Specifically, this is achieved by utilizing waveform analysis techniques in seismic data processing, combined with the calculated downwave travel time... and rising wave travel time The reflected wave signal corresponding to the actual travel time is located on the corresponding seismic trace. Then, the amplitude information is extracted from these reflected wave signals to obtain the actual travel time amplitude data.

[0069] In specific implementation, the actual travel time amplitude data is mapped to each sampling point corresponding to the total travel time data, and the amplitude data of each sampling point are interferometrically superimposed based on the extended shot-receiver distance information to obtain the VSP imaging gather. First, based on the total running time data The time position of each sampling point is determined, and then the extracted actual travel-time amplitude data is mapped one by one to the corresponding sampling points according to these time positions. During this process, extended shot-receiver distance information is utilized. As a parameter for the shot-receiver distance, the amplitude data at each sampling point is ensured to correspond to the expanded shot-receiver distance. Finally, the amplitude data of all mapped waves within the aperture at the imaging point are subjected to interferometric superposition processing. By superimposing the amplitudes of reflected waves from different paths, the continuity of the phase axis and the clarity of the imaging are enhanced, thereby generating a VSP imaging gather suitable for conventional velocity analysis.

[0070] Step S240: Perform velocity analysis on the VSP imaging gather to obtain the offset imaging results.

[0071] Velocity analysis is performed on the VSP imaging gather to obtain the migration imaging results, including: Based on the hyperbolic time-distance relationship, velocity picking is performed on the VSP imaging gather to obtain the root mean square velocity information of the target. Based on the target root mean square velocity, the VSP imaging gather is dynamically corrected and cut off to obtain the corrected VSP imaging gather. The corrected VSP imaging gathers are stacked to obtain the offset imaging result.

[0072] In specific implementation, the target root mean square velocity information is obtained by velocity picking of the VSP imaging gather based on the hyperbolic time-distance relationship: Using VSP imaging gathers with extended shot-receiver offsets, the time-distance relationship approximately follows a hyperbolic law, similar to conventional surface seismic data. By analyzing the hyperbolic characteristics in the imaging gathers, velocity analysis techniques (such as hyperbolic fitting of common reflection point gathers) are employed to determine the optimal root-mean-square velocity. Specifically, based on the arrival time of reflected waves under different shot-receiver offsets, a velocity model that best fits the hyperbolic characteristics is fitted, thereby obtaining the target root-mean-square velocity information.

[0073] After travel time and shot-receiver distance expansion, the time-distance relationship of the imaging gathers can be expressed as:

[0074] In the formula The gun-receiver distance is h Two-way travel time; When the gun is at zero distance, ; h It is the extended gun-receiver distance. ; It is the root mean square velocity at the imaging point.

[0075] The specific derivation is as follows:

[0076] When the assumption of a homogeneous medium or a slowly changing medium is adopted, the above equation can be simplified to:

[0077] This expression is consistent with the hyperbolic time-distance relationship of conventional ground seismic data, enabling VSP imaging gathers to be used with conventional velocity analysis techniques.

[0078] In practice, the VSP imaging gather is dynamically corrected and clipped based on the target root mean square velocity to obtain the corrected VSP imaging gather in the following manner: First, using the root mean square velocity of the target obtained through velocity analysis, the theoretical reflection time delay for each seismic trace under different shot-receiver offsets is calculated. Then, based on these theoretical delays, time correction (dynamic correction) is performed on each seismic trace in the VSP imaging gather to eliminate the difference in reflected wave arrival time caused by different shot-receiver offsets, aligning the phase axes on the time axis. Next, redundant gather portions are removed according to imaging requirements, retaining only effective reflection information, thus obtaining the corrected VSP imaging gather.

[0079] In specific implementation, the offset imaging result is obtained by superimposing the corrected VSP imaging gathers as follows: After dynamic correction and shearing, the seismic traces are grouped according to the shot-receiver offset, and the amplitudes of the traces in each group are time-aligned and superimposed. This superposition process enhances the continuity of the phase axis and the signal-to-noise ratio of the reflected signal, while suppressing random noise, thus obtaining clear and accurate migration imaging results.

[0080] As a specific exemplary embodiment, the above embodiments are used with actual 3D VSP data to verify the effectiveness of the technology. (See reference...) Figure 4 This is the original single-shot record of the actual 3D VSP in the target work area, which, after necessary pre-stack preprocessing, yielded the VSP upflow wave field record. (Reference) Figure 5 By using the up-wave record and the corresponding root-mean-square velocity field as inputs for three-dimensional VSP pre-stack time migration calculation, VSP imaging gathers can be obtained. (Refer to...) Figure 6 For this imaging gather, velocity picking can be directly performed using conventional ground seismic velocity analysis methods. (Reference) Figure 7 The VSP pre-stack time-migrated profile can be obtained by performing dynamic correction and cut-off of the VSP imaging gathers by picking up the speed and then stacking them.

[0081] The final VSP imaging profile shows clear wave group characteristics, good wave group features, and excellent imaging effect, verifying the effectiveness and applicability of the three-dimensional VSP pre-stack time migration imaging method.

[0082] It should be noted that the method of this disclosure embodiment can be executed by a single device, such as a computer or server. The method of this embodiment can also be applied to 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 of this disclosure embodiment, and the multiple devices will interact with each other to complete the method described.

[0083] It should be noted that the above description describes some embodiments of this disclosure. 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.

[0084] Based on the same inventive concept, and corresponding to any of the above embodiments, this disclosure also provides a three-dimensional VSP pre-stack time-shift imaging device.

[0085] refer to Figure 8 The three-dimensional VSP pre-stack time-lapse imaging device includes: The depth information determination module 810 is configured to determine the original seismic data of the three-dimensional VSP, perform depth calculation based on the original seismic data, and obtain the depth information of the imaging point. The travel time data determination module 820 is configured to perform segmented travel time calculation on the depth information of the imaging point to obtain total travel time data; The imaging gather determination module 830 is configured to perform shot-receiver distance expansion based on the total travel time data to obtain the VSP imaging gather; The imaging result determination module 840 is configured to perform velocity analysis on the VSP imaging gather to obtain the offset imaging result.

[0086] In this exemplary embodiment, the depth information determination module 810 is specifically configured as follows: The original seismic data of the 3D VSP is determined, and an imaging grid is constructed based on the geometric parameters of the original seismic data. The depth information of the imaging points is obtained by calculating the depth based on the root mean square velocity field of the P-waves in the original seismic data and the horizontal position information of the imaging grid.

[0087] In this exemplary embodiment, the timekeeping data determination module 820 is specifically configured as follows: The geometric distribution characteristics of the original seismic data are determined to define the aperture, thus obtaining the imaging migration aperture. Based on the imaging offset aperture and the imaging point depth information, the root mean square velocity information of the strata corresponding to each ray path segment is obtained; based on each root mean square velocity information, segmented travel time calculation is performed to obtain downwave travel time data, upwave travel time data and virtual travel time data; based on the downwave travel time data, the upwave travel time data and the virtual travel time data, the total travel time data is obtained.

[0088] In this exemplary embodiment, the imaging gather determination module 830 is specifically configured as follows: The shot location information, borehole geophone location information, and virtual surface geophone location information of the original seismic data are determined. Based on the shot location information, borehole geophone location information, and virtual surface geophone location information, extended shot-receiver offset information is obtained. Amplitude is extracted based on the down-wave travel time data and the up-wave travel time data to obtain actual travel time amplitude data. The actual travel time amplitude data is mapped to each sampling point corresponding to the total travel time data, and the amplitude data of each sampling point is interferometrically superimposed based on the extended shot-receiver offset information to obtain the VSP imaging gather.

[0089] In this exemplary embodiment, the imaging gather determination module 830 is specifically configured as follows: Based on the hyperbolic time-distance relationship, velocity picking is performed on the VSP imaging gather to obtain the root mean square velocity information of the target; dynamic correction and clipping are performed on the VSP imaging gather based on the root mean square velocity of the target to obtain the corrected VSP imaging gather; the corrected VSP imaging gather is then stacked to obtain the offset imaging result.

[0090] For ease of description, the above apparatus is described in terms of its functions, divided into various modules. Of course, in implementing this disclosure, the functions of each module can be implemented in one or more software and / or hardware.

[0091] The apparatus of the above embodiments is used to implement the corresponding three-dimensional VSP pre-stack time migration imaging method in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0092] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this disclosure 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 three-dimensional VSP pre-stack time migration imaging method described in any of the above embodiments.

[0093] Figure 9 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.

[0094] 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.

[0095] 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.

[0096] The input / output interface 1030 is used to connect input / output modules to realize information input and output. The input / output modules can be configured as components in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touch screens, microphones, various sensors, etc., and output devices may include displays, speakers, vibrators, indicator lights, etc.

[0097] 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.).

[0098] 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.

[0099] 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.

[0100] The electronic devices described above are used to implement the corresponding three-dimensional VSP pre-stack time migration imaging method in any of the foregoing embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0101] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this disclosure also provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to execute the three-dimensional VSP pre-stack time-lapse imaging method as described in any of the above embodiments.

[0102] 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 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.

[0103] The aforementioned non-transitory computer-readable storage media can be any available medium or data storage device that a computer can access, including but not limited to magnetic storage (e.g., floppy disks, hard disks, magnetic tapes, magneto-optical disks (MOs), etc.), optical storage (e.g., CDs, DVDs, BDs, HVDs, etc.), and semiconductor storage (e.g., ROMs, EPROMs, EEPROMs, non-volatile memory (NAND flash), solid-state drives (SSDs)).

[0104] The computer instructions stored in the storage medium of the above embodiments are used to cause the computer to execute the three-dimensional VSP pre-stack time migration imaging method as described in any of the embodiments in the exemplary method section above, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0105] Based on the same inventive concept, corresponding to the three-dimensional VSP pre-stack time migration 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 three-dimensional VSP pre-stack time migration imaging method. Corresponding to the execution entity for each step in each embodiment of the three-dimensional VSP pre-stack time migration imaging method, the processor executing the corresponding step can belong to the corresponding execution entity.

[0106] The computer program product of the above embodiments is used to enable the computer and / or the processor to execute the three-dimensional VSP pre-stack time migration 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.

[0107] Those skilled in the art will recognize that embodiments of this disclosure can be implemented as a system, method, or computer program product. Therefore, this disclosure can be implemented as entirely hardware, entirely software (including firmware, resident software, microcode, etc.), or a combination of hardware and software, generally referred to herein as a "circuit," "module," or "system." Furthermore, in some embodiments, this disclosure can also be implemented as a computer program product contained in one or more computer-readable media, which includes computer-readable program code.

[0108] Any combination of one or more computer-readable media may be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example,, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (not exhaustive) of a computer-readable storage medium may include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device.

[0109] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0110] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0111] Computer program code for performing the operations of this disclosure can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0112] It should be understood that each block of a flowchart and / or block diagram, as well as combinations of blocks in a flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine that, when executed by a computer or other programmable data processing device, creates means for implementing the functions / operations specified in the blocks of the flowchart and / or block diagram.

[0113] These computer program instructions may also be stored in a computer-readable medium that enables a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce a product comprising an instruction apparatus that implements the functions / operations specified in the boxes of a flowchart and / or block diagram.

[0114] Computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, such that the instructions that execute on the computer or other programmable apparatus can provide a process for implementing the functions / operations specified in the boxes of a flowchart and / or block diagram.

[0115] Furthermore, although the operations of the methods of this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all of the operations shown must be performed to achieve the desired result. Rather, the steps depicted in the flowcharts may be executed in a different order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0116] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. Each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0117] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to the embodiments of this application, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] While the spirit and principles of this disclosure have been described with reference to several specific embodiments, it should be understood that this disclosure is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for convenience of expression. This disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the appended claims is to be interpreted in the broadest sense, thereby encompassing all such modifications and equivalent structures and functions.

Claims

1. A three-dimensional VSP pre-stack time migration imaging method, characterized in that, include: The original seismic data of the 3D VSP is determined, and depth calculation is performed based on the original seismic data to obtain the depth information of the imaging points; The total travel time data is obtained by segmenting the depth information of the imaging points; Based on the total travel time data, the shot-receiver distance is extended to obtain the VSP imaging gather; Velocity analysis was performed on the VSP imaging gather to obtain the offset imaging results.

2. The method according to claim 1, characterized in that, The process of calculating depth based on the original seismic data to obtain imaging point depth information includes: An imaging grid is constructed based on the geometric parameters of the original seismic data. Depth calculation is performed based on the root mean square velocity field of the P-waves in the original seismic data and the horizontal position information of the imaging grid to obtain the depth information of the imaging point.

3. The method according to claim 1, characterized in that, The step of segmenting the depth information of the imaging points to calculate the total travel time data includes: The geometric distribution characteristics of the original seismic data are determined to define the aperture, thus obtaining the imaging migration aperture. Based on the imaging offset aperture and the imaging point depth information, the root mean square velocity information of the strata corresponding to each ray path segment is obtained; Segmented travel time calculations are performed based on each of the root mean square velocity information to obtain downwave travel time data, upwave travel time data and virtual travel time data; The total travel time data is obtained based on the downwave travel time data, the upwave travel time data, and the virtual travel time data.

4. The method according to claim 3, characterized in that, The process of extending the shot-receiver distance based on the total travel time data to obtain the VSP imaging gather includes: The shot location information, borehole geophone location information, and virtual surface geophone location information of the original seismic data are determined. Based on the shot location information, borehole geophone location information, and virtual surface geophone location information, the extended shot-receiver distance information is obtained. Based on the total travel time data and the extended shot-receiver distance information, amplitude mapping and interferometric superposition are performed to obtain the VSP imaging gather.

5. The method according to claim 4, characterized in that, The process of performing amplitude mapping and interferometric superposition based on the total travel time data and the extended shot-receiver distance information to obtain the VSP imaging gather includes: Amplitude is extracted based on the downwave travel time data and the upwave travel time data to obtain the actual travel time amplitude data; The actual travel time amplitude data is mapped to each sampling point corresponding to the total travel time data, and the amplitude data of each sampling point is interferometrically superimposed based on the extended shot-receiver distance information to obtain the VSP imaging gather.

6. The method according to claim 1, characterized in that, The velocity analysis of the VSP imaging gather to obtain the migration imaging results includes: Based on the hyperbolic time-distance relationship, velocity picking is performed on the VSP imaging gather to obtain the root mean square velocity information of the target. Based on the target root mean square velocity, the VSP imaging gather is dynamically corrected and cut off to obtain the corrected VSP imaging gather. The corrected VSP imaging gathers are stacked to obtain the offset imaging result.

7. A three-dimensional VSP pre-stack time-lapse imaging device, characterized in that, include: The depth information determination module is configured to determine the original seismic data of the three-dimensional VSP, perform depth calculation based on the original seismic data, and obtain the depth information of the imaging points. The travel time data determination module is configured to perform segmented travel time calculation on the depth information of the imaging point to obtain total travel time data; The imaging gather determination module is configured to perform shot-receiver distance expansion based on the total travel time data to obtain the VSP imaging gather; The imaging result determination module is configured to perform velocity analysis on the VSP imaging gather to obtain the offset imaging result.

8. An electronic device, characterized in that, It includes 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 described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions for causing the computer to perform the method of any one of claims 1 to 6.

10. A computer program product, characterized in that, It includes computer program instructions that, when run on a computer, cause the computer to perform the method as described in any one of claims 1 to 6.

Images