Complex structure area VSP wave field separation method, system, equipment and medium

Abstract

The invention discloses a complex structure area VSP wave field separation method, system and device and a medium, and the method comprises the steps: taking actual VSP observation data as the basis, and precisely obtaining stratum velocity information; multi-source geological exploration information is utilized to construct a plurality of groups of possible forward models to comprehensively cover possible features of a complex structure, and a target model obtained through subsequent matching and screening can accurately reflect a real geological structure, so that the problems of single model data source and inaccurate representation in an existing method are solved, and the method is suitable for large-scale popularization and application. A reliable model basis is provided for wave field separation; according to the method, an optimally matched target model simulation wave field is taken as a reference basis, propagation paths and wave field characteristics of target waves such as reflected longitudinal waves and interference waves are determined, the target waves and the interference waves which are overlapped and confused in a complex structure area can be accurately distinguished, the influence of the interference waves is effectively eliminated, and the accuracy and the reliability of the complex structure area are improved. The technical problems of strong VSP wave field interference and low separation precision in a complex structure area are effectively solved.

Description

Technical Field

[0001] This application belongs to the field of seismic exploration data processing technology, specifically relating to a method, system, equipment, and medium for VSP wavefield separation in complex tectonic regions. Background Technology

[0002] Vertical seismic profiling (VSP) technology, as an important tool in seismic exploration, has been widely used in oil and gas resource exploration and development due to its advantages such as close proximity of observation points to the formation, high signal-to-noise ratio of received signals, and direct acquisition of formation wavefield information near the well. VSP wavefield separation is the core step in VSP data processing. Its purpose is to separate target waves (such as reflected P-waves and reflected S-waves) and interfering waves (such as direct waves, surface waves, and multiples) from the complex observed wavefield, providing a reliable data foundation for subsequent formation parameter inversion, structural interpretation, and reservoir prediction.

[0003] However, VSP wavefield separation faces severe challenges in complex tectonic zones (such as thrust zones, fold zones, and fault-developed areas). On the one hand, complex structures lead to variable stratigraphic attitudes and discontinuous lithological interfaces, resulting in complex wavefield propagation paths. The propagation characteristics of target waves and interfering waves overlap and become confused, making effective differentiation difficult. On the other hand, surface conditions in complex tectonic zones are often harsh, limiting the resolution and signal-to-noise ratio of surface seismic exploration data, making it difficult to provide accurate tectonic constraint information for VSP wavefield separation.

[0004] Existing VSP wavefield separation methods mainly include separation methods based on wavefield propagation characteristics (such as filtering methods and polarization separation methods) and separation methods based on wave equations (such as wave equation forward modeling). Among them, filtering methods and polarization separation methods mainly rely on the differences between the target wave and the interfering wave in terms of frequency, amplitude, polarization direction, etc. However, in complex tectonic regions, these differences are often not significant, resulting in low separation accuracy and problems such as target wave distortion or residual interfering waves. Although the wave equation forward modeling method introduces the constraint of the stratigraphic model, the forward modeling models constructed by existing methods are mostly based on a single data source (such as using only surface seismic data or well logging data), which is difficult to accurately represent the true characteristics of complex structures. This leads to a low degree of matching between the forward modeled wavefield and the actual wavefield, thus affecting the wavefield separation effect. Summary of the Invention

[0005] To address the problems existing in current VSP wavefield separation methods, this application proposes a VSP wavefield separation method, system, equipment, and medium for complex tectonic zones. Utilizing the multi-source nature of geological exploration data, multiple sets of possible forward modeling models are constructed. Through comparative analysis of the simulated wavefield and the actual wavefield, a target model that optimally matches the characteristics of the real wavefield is selected. This target model is then used to achieve high-precision, high-fidelity separation of the VSP wavefield in complex tectonic zones. This effectively solves the technical challenges of strong wavefield interference and low separation accuracy in complex tectonic zones, providing reliable technical support for subsequent seismic data interpretation and precise oil and gas resource exploration.

[0006] This application is achieved through the following technical solution:

[0007] A method for VSP wavefield separation in complex tectonic regions includes:

[0008] The zero-well-spacing VSP observation system based on the target well collects and processes actual VSP observation data in complex structural areas to obtain VSP velocities.

[0009] Based on the VSP velocity and combined with multi-source geological exploration data of the target well area, multiple sets of forward modeling models with differentiated structural characteristics are constructed.

[0010] The simulated wavefield obtained by each group of forward models is matched with the actual wavefield, and the optimal forward model is selected as the target model.

[0011] Using the simulated wavefield of the target model as a reference, the actual VSP wavefield is finely separated.

[0012] 2. The method for VSP wavefield separation in a complex structural region according to claim 1, characterized in that the process of obtaining the VSP velocity includes:

[0013] The actual VSP observation data collected is preprocessed to obtain preprocessed VSP data containing first arrival and reflected wave information; wherein, the actual VSP observation data refers to the original zero-bias and non-zero-bias VSP records that can cover a single well or multiple wells, and the data can cover the target exploration layer, and the record length meets the requirements for complete reception of first arrival.

[0014] Based on the preprocessed VSP data, the first arrival wave travel time is picked using a first arrival fitting method that combines automatic picking with manual correction.

[0015] Based on the initial arrival wave travel time, the velocity is calculated to obtain the VSP velocity.

[0016] In some embodiments, the method of picking the first arrival travel time using a combination of automatic picking and manual correction includes:

[0017] The energy ratio method is used to automatically locate the maximum position of the first arrival wave crest and obtain the initial first arrival travel time data;

[0018] By combining the wave field propagation law of the complex structure in the target well area, the initial first arrival travel time data is manually corrected to remove abnormal pick-up points caused by wave field interference, and finally the first arrival travel time data is obtained.

[0019] In some implementations, the construction process of multiple sets of forward models includes:

[0020] The VSP velocity information is fused with the ground seismic horizon interpretation results, and an initial forward model is constructed using stratigraphic data as the verification basis.

[0021] The multi-source geological exploration data is fused with the initial forward model, and different combinations of values ​​are set around the key parameters of the core structure. At the same time, the details of the deep strata occurrence are adjusted by combining well logging dip data to generate multiple sets of forward models with differentiated structural features, ensuring that the model can fully cover the possible features of complex structures.

[0022] The multi-source geological exploration data includes the analysis results of complex structural models, actual drilling engineering data, and well logging data.

[0023] In some implementations, the selection process for the target model includes:

[0024] Forward modeling simulation is performed using multiple sets of the aforementioned forward modeling models, and an observation system consistent with the actual VSP observation is set up to obtain the simulated wavefield corresponding to each set of the aforementioned forward modeling models.

[0025] Several reflection wave groups were selected for wave group feature comparison, and the reflection similarity between each simulated wave field and the actual wave field was calculated as the wave group feature similarity.

[0026] Calculate the travel time difference between each simulated wavefield and the actual wavefield in different wave groups, and sum the absolute values ​​of the travel time differences in different wave groups to obtain the travel time deviation.

[0027] The similarity of wave group features and travel time deviations between each simulated wavefield and the actual wavefield are weighted and summed to obtain the comprehensive matching degree between each simulated wavefield and the actual wavefield.

[0028] The forward model corresponding to the simulated wavefield with the highest comprehensive matching degree is selected as the target model.

[0029] In some implementations, the step of using the simulated wavefield of the target model as a reference for refining the actual VSP wavefield includes:

[0030] Based on the simulated wave field corresponding to the target model, the propagation paths and wave field characteristics of the target wave and the interference wave are determined. Using the target wave in the simulated wave field as a reference, the target wave characteristics of the actual wave field are determined.

[0031] The distribution characteristics of the target wave and the interference wave in the frequency-wavenumber domain are determined. Based on the distribution characteristics, an adaptive FK filter operator is designed. By dividing the FK domain boundary of the target wave and the interference wave, the actual wave field is filtered in the FK domain to complete the initial suppression of the strong interference wave.

[0032] The target wave field is obtained by performing secondary processing on the FK domain filtered wave field using median filtering.

[0033] Secondly, this application proposes a VSP wavefield separation system for complex tectonic regions, comprising:

[0034] The velocity acquisition module is configured to: acquire and process actual VSP observation data in complex structural areas using a target well-based zero-well-spacing VSP observation system to obtain VSP velocity;

[0035] The model building module is configured to: based on the VSP velocity and combined with multi-source geological exploration data of the target well area, construct multiple sets of forward models with differentiated structural features;

[0036] The matching and filtering module is configured to match the simulated wavefield obtained by each group of forward modeling models with the actual wavefield, and filter out the optimal forward modeling model as the target model.

[0037] Furthermore, the separation module is configured to perform fine separation of the actual VSP wavefield using the simulated wavefield of the target model as a reference.

[0038] In some implementations, the matching and filtering module includes:

[0039] The forward modeling unit is configured to: perform forward modeling simulation using multiple sets of the forward modeling models, set up an observation system consistent with the actual VSP observations, and obtain the simulated wavefield corresponding to each set of the forward modeling models;

[0040] The comparison and evaluation unit is configured to: select several reflection wave groups for wave group feature comparison, calculate the reflection similarity between each simulated wave field and the actual wave field as the wave group feature similarity; at the same time, calculate the travel time difference between each simulated wave field and the actual wave field in different wave groups, and sum the absolute values ​​of the travel time difference values ​​of different wave groups to obtain the travel time deviation.

[0041] Furthermore, the target selection unit is configured to: perform a weighted summation of the wave group feature similarity and travel time deviation corresponding to each simulated wavefield and the actual wavefield to obtain the comprehensive matching degree between each simulated wavefield and the actual wavefield; and select the forward model corresponding to the simulated wavefield with the highest comprehensive matching degree as the target model.

[0042] Thirdly, this application proposes an electronic device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement any of the above-described embodiments of the complex structure region VSP wavefield separation method.

[0043] Fourthly, this application proposes a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements any of the above-described methods for separating the wave field of the complex structure region VSP.

[0044] This application proposes a wavefield separation method for VSP (Very Spatial Probing) in complex structural regions. Based on actual VSP observation data, it accurately obtains formation velocity information. By utilizing multi-source information such as complex structural model analysis results, surface seismic exploration data, actual drilling engineering data, and well logging data, it constructs multiple sets of possible forward modeling models to comprehensively cover the possible characteristics of complex structures. The target model obtained through subsequent matching and screening accurately reflects the real geological structure, solving the problems of single model data source and inaccurate representation in existing methods, and providing a reliable model foundation for wavefield separation. This method uses the simulated wavefield of the optimally matched target model as a reference benchmark to clarify the propagation path and wavefield characteristics of target waves such as reflected P-waves and interfering waves, and can accurately distinguish between superimposed P-waves and interfering waves in complex structural regions. The method effectively eliminates the influence of interference waves by confusing the target wave and interfering waves, thus solving the technical challenges of strong interference and low separation accuracy in VSP wavefields in complex structural areas. This method is applicable to multiple complex structural scenarios, including thrust zones, fold zones, and fault-developed areas, overcoming the limitations of existing VSP wavefield separation methods in complex structural regions. This allows VSP technology to play a role in more complex exploration areas, providing high-quality data support for subsequent seismic data interpretation, reservoir prediction, and oil and gas resource evaluation. It helps improve the accuracy and efficiency of oil and gas resource exploration and reduce exploration costs. Furthermore, the method has clear steps, and the algorithms for each step have mature technical foundations, allowing implementation on existing seismic data processing software platforms, making it easy to apply and promote in engineering.

[0045] Correspondingly, the VSP wave field separation system, electronic device, and computer-readable storage medium proposed in this application also possess the same technical effects as described above. Attached Figure Description

[0046] The accompanying drawings, which are included to provide a further understanding of the embodiments of this application and form part of this application, do not constitute a limitation on the embodiments of this application. In the drawings:

[0047] Figure 1 This is a flowchart of the VSP wavefield separation method for complex structural regions proposed in this application.

[0048] Figure 2(a) shows the forward model of the target formation being a flat layer under the interpretation of dip logging;

[0049] Figure 2(b) shows the forward model of the target formation as an oblique layer under the interpretation of dip logging;

[0050] Figure 2(c) shows the forward model constructed based on the tectonic model as interpreted by geologists;

[0051] Figure 3 This is a block diagram illustrating the principle of the VSP wavefield separation system for complex structures proposed in this application.

[0052] Figure 4 This is a schematic diagram of the electronic device proposed in the embodiments of this application;

[0053] Figure 5 This is a schematic diagram of a computer-readable storage medium proposed in an embodiment of this application.

[0054] Figure reference numerals and corresponding component names:

[0055] 300 - Wave field separation system; 301 - Velocity acquisition module; 302 - Model building module; 303 - Matching and filtering module; 304 - Separation module; 400 - Electronic device; 410 - Memory; 420 - Processor; 411 - Computer program A; 500 - Computer-readable storage medium; 511 - Computer program B. Detailed Implementation

[0056] In the following, the terms “comprising” or “may include” as used in the various embodiments of this application indicate the presence of a function, operation, or element of the invention and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in the various embodiments of this application, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0057] In various embodiments of this application, the expression "or" or "at least one of A and / or B" includes any combination or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A and / or B" may include A, may include B, or may include both A and B.

[0058] The terms used in the various embodiments of this application (such as "first," "second," etc.) may modify various constituent elements in the various embodiments, but do not limit the corresponding constituent elements. For example, the above terms do not limit the order and / or importance of the elements. The above terms are only used for the purpose of distinguishing one element from other elements. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0059] It should be noted that if a description is made of "connecting" one component to another, then the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when a component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.

[0060] The terminology used in the various embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. The terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0061] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this application are only for explaining this application and are not intended to limit this application.

[0062] To address the shortcomings of existing technologies in VSP wavefield separation in complex structural regions, such as strong wavefield interference, low separation accuracy, and inaccurate forward model representation, this application proposes a method for VSP wavefield separation in complex structural regions. This method is based on actual VSP observation data to accurately obtain formation velocity information and fully utilizes multi-source geological exploration data, including analytical results of complex structural models, surface seismic exploration data, actual drilling data, and well logging data, to construct multiple sets of possible forward models. This solves the problems of single data source and inaccurate representation in existing forward models. Then, by comparing and matching the forward modeled wavefield with the actual observed wavefield, the optimal target model is selected. The simulated wavefield of the optimal target model is used as a benchmark to achieve refined wavefield separation, improving the accuracy and fidelity of VSP wavefield separation in complex structural regions. This effectively solves the problems of complex wavefield propagation paths and confusion between target and interfering waves in complex structural regions, providing reliable technical support for subsequent seismic data interpretation and precise oil and gas resource exploration.

[0063] like Figure 1 As shown, the wavefield separation method proposed in this application includes the following steps:

[0064] Step 1: Based on the zero-source-distance VSP observation system of the target well, collect and process the actual VSP observation data of the complex structural area to obtain the VSP velocity;

[0065] Step 2: Based on VSP velocity and combined with multi-source geological exploration data of the target well area, construct multiple sets of forward modeling models with differentiated structural characteristics;

[0066] Step 3: Match the simulated wavefield obtained by the forward modeling of each group with the actual wavefield, and select the optimal forward model as the target model.

[0067] Step 4: Using the simulated wavefield corresponding to the target model as a reference, perform fine separation of the actual VSP wavefield.

[0068] Furthermore, in the embodiments of this application, the actual VSP observation data in step 1 refers to the raw VSP records of single or multiple wells with zero bias and non-zero bias, ensuring that the data completely covers the target exploration layer and that the record length meets the requirements for complete reception of the first arrival wave; based on this, the VSP velocity acquisition process includes:

[0069] The actual VSP observation data collected is preprocessed to obtain preprocessed VSP data containing effective wavefield information such as first arrival wave and reflected wave. Specifically, the preprocessing method may include correcting the lead information of the collected raw VSP data to ensure that the basic information such as well depth and coordinates of each receiving point is accurate. Then, a combination algorithm of "power frequency notch filtering (50Hz) + linear interference removal" is used to suppress noise, eliminating the influence of industrial interference and linear interference on the identification of first arrival wave, thereby obtaining the preprocessed VSP data.

[0070] Based on the preprocessed VSP data, the first arrival travel time (i.e., the travel time of the first arrival wave to each receiving point) is obtained by a first arrival fitting method that combines automatic picking with manual correction. Specifically, the first arrival picking process includes: firstly, automatically locating the maximum position of the first arrival wave peak using the energy ratio method to obtain the initial first arrival travel time data; then, combining the wave field propagation law of the complex structure of the region, manually correcting the automatic picking results, eliminating abnormal picking points caused by wave field interference, and finally obtaining the first arrival travel time data of the effective receiving points to ensure the reliability of the first arrival travel time data.

[0071] Based on the picked first-arrival travel time, velocity calculations are performed to obtain accurate VSP velocities, including vertical layer velocities for each stratum, providing a precise velocity foundation for subsequent forward model construction. It is understood that calculating VSP velocities based on first-arrival travel time is a standard practice in this field and will not be elaborated upon here.

[0072] Furthermore, the multi-source geological exploration data in step 2 of this application embodiment includes: analytical results of complex structural models, obtained through methods such as surface seismic profiles and stratigraphic interpretation, and geological outcrop surveys, clarifying the structural type (such as thrust faults, folds, grabens, etc.); actual drilling engineering data, including stratigraphic layering data and lithological descriptions during the drilling process; and logging data, including sonic logging, dip logging, and other data. Based on this, the construction process of multiple sets of forward modeling models with differentiated structural characteristics includes:

[0073] The VSP velocity information was fused with the surface seismic horizon interpretation results, and an initial forward model was constructed using well stratification data as the verification basis.

[0074] Using the initial forward model as a framework, different combinations of values ​​are set around the core structural key parameters (stratum dip angle, fault strike, etc.). At the same time, the details of deep stratum attitude are adjusted by combining well logging dip angle data, generating multiple sets of forward models with differentiated structural characteristics to ensure that the model can fully cover the possible characteristics of complex structures.

[0075] Furthermore, in step 3 of this application embodiment, the target model selection process includes:

[0076] The multiple forward models constructed in step 2 are used to perform forward modeling, and an observation system consistent with the actual VSP observations is set up to obtain the simulated wavefield corresponding to each forward model. Setting up an observation system consistent with the actual VSP observations means that the parameters of the actual VSP observation system (i.e., the actual zero-source-distance observation system) are strictly matched during the simulation process, including the source location, excitation direction, excitation energy, receiving depth, detector spacing, and sampling spacing, all of which are consistent with the actual acquisition.

[0077] A multi-dimensional wavefield comparison and evaluation system was constructed, selecting wave group feature similarity and travel time deviation as two core evaluation indicators. A weighted summation method was used to calculate the comprehensive matching degree between each simulated wavefield and the actual wavefield. The forward model corresponding to the simulated wavefield with the highest comprehensive matching degree (i.e., the largest value) was determined as the target model. Wave group feature similarity refers to the comparison of wave group features of a certain number of important stratigraphic reflection wave groups. The similarity between the simulated and actual wavefields in these stratigraphic layers is calculated (i.e., the percentage of matches among several stratigraphic reflection wave group feature comparisons; for example, if four out of five important reflection wave groups match, the similarity is 80%), with a value range of 0 to 1. Travel time deviation refers to the calculation of the travel time difference between the simulated and actual wavefields for the same wave group (such as first arrival wave and main reflection wave). The absolute values ​​of the travel time differences of different wave groups are summed to obtain the travel time deviation. It should be noted that the travel time deviation is normalized before being included in the overall matching degree calculation. During the overall matching degree calculation, the weight coefficients of wave group feature similarity and travel time deviation can be set according to the actual data situation. For example, the weight of wave group feature similarity is 0.8 and the weight of travel time deviation is 0.2.

[0078] Furthermore, in step 4 of this application embodiment, the actual VSP wavefield refinement separation process includes:

[0079] Based on the simulated wave field corresponding to the target model, the propagation path and wave field characteristics of the target wave and the interference wave are determined. Using the target wave in the simulated wave field as a reference, the target wave characteristics (such as propagation direction) of the actual VSP observation wave field (i.e., the actual wave field) are determined.

[0080] The distribution characteristics of the target wave and interference wave in the frequency-wavenumber (FK) domain are determined. Based on these characteristics, an adaptive FK filter operator is designed. By dividing the FK domain boundaries between the target wave and the interference wave, the actual VSP observed wavefield (i.e., the actual wavefield) is filtered in the FK domain to remove the energy region corresponding to the interference wave and retain the energy of the target wave, thus completing the initial suppression of strong interference waves (surface waves, direct waves, etc.). Then, for the local pulse interference remaining in the wavefield after FK domain filtering, median filtering is used for secondary processing to eliminate interference while preserving the waveform characteristics of the target wave to the greatest extent, finally obtaining a high-precision, high-fidelity target wavefield.

[0081] To verify the effectiveness and practicality of the separation method proposed in this application, this application takes an oil and gas exploration project in a complex deep fold-fracture structure as the research object, and elaborates in detail the specific implementation process and effect verification of the classification method proposed in this application. The strata in this area are disordered, with intersecting faults and a target well depth of 7000m. The strata in this structural area are complex, with faults and the main target layer is buried at a depth of 5000-6800m.

[0082] A zero-source-distance VSP observation system was adopted, with the seismic source located on the ground directly above the wellhead. The excitation method was controlled source excitation (suitable for deep exploration needs), with an excitation energy of 30 kg and an excitation direction perpendicular to the structural strike. The receiving end used a high-temperature and high-pressure three-component geophone, arranged along the wellbore of the target well, with a receiving depth range of 20 m to 6800 m, a geophone spacing of 20 m, a sampling interval of 1 ms, and a recording length of 16 s to ensure complete reception of the first arrival wave and the reflected wave from the deep target layer. Zero-biased VSP raw records of the target well were collected, and multi-source geological exploration data of the area were collected, including: (1) analysis results of complex structural models; (2) actual drilling engineering data: stratigraphic data of the target well; (3) logging data: dip logging curves, lithological data; (4) surface seismic data: deep post-stack seismic profiles and stratigraphic interpretation results.

[0083] The model establishment and wavefield separation are performed using the separation method proposed in the embodiments of this application. The specific process is as follows:

[0084] S1, VSP velocity acquisition: The VSP velocity is calculated through step 1 above, and verified by logging lithology to finally obtain the vertical layer velocity of each stratum, providing an accurate velocity basis for the subsequent forward model construction.

[0085] S2. Construction of multiple possible forward modeling models: First, an initial forward model is constructed with a vertical depth range of 0-6800m and a horizontal range of 0m-3000m, with a grid precision of 16m×16m (to improve the accuracy of deep structural characterization). Then, the formation dip angle is set to 0-180°, and the fault strike is set to 0-90°. At the same time, the details of the deep strata's attitude are adjusted by combining well logging dip angle data to generate multiple sets of forward modeling models with differentiated structural characteristics, covering the main combination patterns of deep fold-fault structures in the region, ensuring that the model fully covers the possible characteristics of complex structures. This application example uses three sets of differentiated forward modeling models as examples: a forward model with a flat target stratum and a forward model with an oblique target stratum constructed based on dip logging interpretation results, and a forward model constructed based on the structural pattern interpreted by geologists, as shown in Figures 2(a), 2(b), and 2(c), respectively. In the figures, the horizontal axis represents the horizontal range in meters, and the vertical axis represents the depth in meters.

[0086] S3. Forward Model Matching and Screening: First, elastic wave forward modeling was performed on three sets of forward models. During the simulation, the parameters of the actual VSP observation system were strictly matched—source location, excitation energy, receiving depth, detector spacing, sampling interval, etc.—to ensure consistency with the actual acquisition, resulting in three sets of corresponding simulated wavefield data. Then, reflection wave groups from four important strata within the target layer covering 5000-6000m were selected for wave group characteristic comparison, and the reflection similarity between the simulated and actual wavefields in each wave group was calculated. Simultaneously, the travel time difference (TOT) values ​​of the first arrival waves of the simulated and actual wavefields, as well as the four reflection wave groups, were calculated. The absolute values ​​were then summed to obtain the travel time deviation. Finally, a weighted summation method was used to calculate the overall matching degree, setting a weight of 0.8 for wave group characteristic similarity and 0.2 for travel time deviation. The calculation results showed that the overall matching degree was highest (0.95) when the forward model was built using the tectonic model interpreted by geologists, and this model was selected as the target model. This target model can accurately characterize the real geological structural features and wavefield propagation laws of the fold-fault interweaving in the study area.

[0087] S4, Refined analysis of the actual VSP wave field: First, using the simulated wave field corresponding to the target model as a reference, the propagation paths of the target wave (reflected longitudinal wave of the target layer at 5000-6800m) and the interference waves (direct wave, surface wave, and multiple reflection wave) are clarified; then, FK filtering and median filtering are performed to remove noise and obtain the target wave field.

[0088] Finally, well-seismic matching verification was performed: the separated target wavefield was overlaid along a corridor and matched with the logging curves and drilling lithology data of the target well. The results showed that the error between the layer depth corresponding to the reflected wave group in the 5000-6800m target section and the drilling layer depth was less than one-thousandth. The wave group amplitude variation trend was consistent with the well logging porosity variation trend, with a matching degree of 90%, which can accurately reflect the lithological and physical property variation characteristics of deep strata. Therefore, the separation method proposed in this application can achieve high-precision and high-fidelity separation of VSP wavefields under complex structural conditions, effectively solving the technical problems of strong wavefield interference and low separation accuracy in complex structural areas, and providing reliable technical support for subsequent seismic data interpretation and precise exploration of oil and gas resources.

[0089] Based on the same technical concept described above, this application also proposes a VSP wavefield separation system for complex structural regions, such as... Figure 3 As shown, the wavefield separation system 300 includes:

[0090] The velocity acquisition module 301 is configured to: acquire and process actual VSP observation data in complex structural areas using a zero-well-spacing VSP observation system based on the target well, thereby obtaining the VSP velocity. The specific VSP velocity acquisition process is as described in step 1 above and will not be repeated here.

[0091] Model building module 302 is configured to construct multiple sets of forward models with differentiated structural characteristics based on VSP velocity and combined with multi-source geological exploration data of the target well area. The specific forward model construction process is as described in step 2 above, and will not be repeated here.

[0092] The matching and filtering module 303 is configured to match the simulated wavefield obtained from the forward modeling of each group with the actual wavefield, and select the optimal forward model as the target model. The specific matching and filtering process is as described in step 3 above, and will not be repeated here.

[0093] Furthermore, the separation module 304 is configured to perform refined separation of the actual VSP wavefield using the simulated wavefield corresponding to the target model as a reference. The specific wavefield separation process is as described in step 4 above, and will not be repeated here.

[0094] Furthermore, the speed acquisition module 301 in this embodiment includes:

[0095] The data preprocessing unit is configured to preprocess the actual VSP observation data to obtain preprocessed VSP data containing effective wavefield information such as first arrival wave and reflected wave; the specific preprocessing method is as described in step 1 above, and will not be repeated here.

[0096] The first arrival picking unit is configured to pick the first arrival wave travel time based on the preprocessed VSP data using a first arrival fitting method that combines automatic picking with manual correction; the specific first arrival picking process is as described in step 1 above, and will not be repeated here.

[0097] In addition, the speed calculation unit is configured to perform speed calculation based on the travel time of the picked-up first arrival wave to obtain the accurate VSP speed.

[0098] Furthermore, the matching and filtering module 303 in this embodiment includes:

[0099] The forward modeling unit is configured to: perform forward modeling simulation using multiple sets of forward modeling models constructed by the model building module 302, set up an observation system consistent with the actual VSP observation, and obtain the simulated wave field corresponding to each set of forward modeling models;

[0100] The comparison and evaluation unit is configured to: construct a comparison and evaluation system with wave group feature similarity and travel time deviation as the core; select a certain number of important strata reflections for wave group feature comparison; calculate the reflection similarity between each simulated wave field and the actual wave field on these strata; and calculate the travel time deviation between each simulated wave field and the actual wave field.

[0101] Furthermore, the target selection unit is configured to: perform weighted summation of the wave group feature similarity and travel time deviation between each simulated wave field and the actual wave field to obtain the comprehensive matching degree between each simulated wave field and the actual wave field, and select the forward model corresponding to the simulated wave field with the highest comprehensive matching degree as the target model.

[0102] Furthermore, the separation module 304 in this embodiment includes:

[0103] The wave field feature recognition unit is configured to: use the simulated wave field corresponding to the target model as a reference to determine the propagation path of the target wave and the interference wave.

[0104] Furthermore, the filtering unit is configured to: determine the distribution characteristics of the target wave and the interference wave in the frequency-wavenumber (FK) domain; based on these distribution characteristics, design an adaptive FK filtering operator; and perform FK domain filtering on the actual VSP observed wavefield (i.e., the actual wavefield) by dividing the FK domain boundary between the target wave and the interference wave, removing the energy region corresponding to the interference wave, retaining the energy of the target wave, and completing the initial suppression of strong interference waves (surface waves, direct waves, etc.); then, for the local pulse interference remaining in the wavefield after FK filtering, a median filter is used for secondary processing to eliminate interference while preserving the waveform characteristics of the target wave to the greatest extent, ultimately obtaining a high-precision, high-fidelity target wavefield.

[0105] Based on the same technical concept described above, this application also proposes an electronic device, such as... Figure 4 As shown, the electronic device 400 includes: a memory 410, a processor 420, and a computer program A411 stored in the memory 410 and executable on the processor 420. When the processor 420 executes the computer program A411, it performs the following steps:

[0106] The zero-well-spacing VSP observation system based on the target well collects and processes actual VSP observation data in complex structural areas to obtain VSP velocities.

[0107] Based on VSP velocity and combined with multi-source geological exploration data of the target well area, multiple sets of forward modeling models with differentiated structural characteristics were constructed.

[0108] The simulated wavefield obtained by the forward modeling of each group of forward models is matched with the actual wavefield, and the optimal forward model is selected as the target model.

[0109] Using the simulated wavefield corresponding to the target model as a reference, the actual VSP wavefield is refined and separated.

[0110] Optionally, when the processor 420 executes the computer program A411, it can implement any of the embodiments in the corresponding examples of the above-described wave field separation method.

[0111] It should be noted that the electronic device proposed in this application embodiment is a device used to implement the above-mentioned wave field separation method. Therefore, based on the above-mentioned wave field separation method proposed in this application embodiment, those skilled in the art can understand the specific implementation method and various variations of the electronic device in this application embodiment. Therefore, how the electronic device specifically implements the above-mentioned wave field separation method will not be described in detail here. Any electronic device used by those skilled in the art to implement the above-mentioned wave field separation method is within the scope of protection of this application.

[0112] Based on the same technical concept described above, embodiments of this application also propose a computer-readable storage medium, such as... Figure 5 As shown, the computer-readable storage medium 500 stores a computer program B511, which, when executed by a processor, performs the following steps:

[0113] The zero-well-spacing VSP observation system based on the target well collects and processes actual VSP observation data in complex structural areas to obtain VSP velocities.

[0114] Based on VSP velocity and combined with multi-source geological exploration data of the target well area, multiple sets of forward modeling models with differentiated structural characteristics were constructed.

[0115] The simulated wavefield obtained by the forward modeling of each group of forward models is matched with the actual wavefield, and the optimal forward model is selected as the target model.

[0116] Using the simulated wavefield corresponding to the target model as a reference, the actual VSP wavefield is refined and separated.

[0117] Optionally, when the computer program B511 is executed by the processor, it can implement any of the embodiments corresponding to the above-described wave field separation method.

[0118] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0119] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0120] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0121] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0122] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0123] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above description is only a specific embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for VSP wavefield separation in complex structural regions, characterized in that, include: The zero-well-spacing VSP observation system based on the target well collects and processes actual VSP observation data in complex structural areas to obtain VSP velocities. Based on the VSP velocity and combined with multi-source geological exploration data of the target well area, multiple sets of forward modeling models with differentiated structural characteristics are constructed. The simulated wavefield obtained by each group of forward models is matched with the actual wavefield, and the optimal forward model is selected as the target model. Using the simulated wavefield of the target model as a reference, the actual VSP wavefield is finely separated.

2. The method for VSP wavefield separation in complex structural regions according to claim 1, characterized in that, The process of obtaining the VSP speed includes: The actual VSP observation data collected is preprocessed to obtain preprocessed VSP data containing first arrival and reflected wave information; wherein, the actual VSP observation data refers to the original zero-bias and non-zero-bias VSP records that can cover a single well or multiple wells, and the data can cover the target exploration layer, and the record length meets the requirements for complete reception of first arrival. Based on the preprocessed VSP data, the first arrival wave travel time is picked using a first arrival fitting method that combines automatic picking with manual correction. Based on the initial arrival wave travel time, the velocity is calculated to obtain the VSP velocity.

3. The method for VSP wavefield separation in complex structural regions according to claim 2, characterized in that, The method of using a combination of automatic picking and manual correction to pick the first arrival travel time includes: The energy ratio method is used to automatically locate the maximum position of the first arrival wave crest and obtain the initial first arrival travel time data; By combining the wave field propagation law of the complex structure in the target well area, the initial first arrival travel time data is manually corrected to remove abnormal pick-up points caused by wave field interference, and finally the first arrival travel time data is obtained.

4. The method for VSP wavefield separation in complex structural regions according to claim 1, characterized in that, The construction process of the multiple sets of forward models includes: The VSP velocity information is fused with the ground seismic horizon interpretation results, and an initial forward model is constructed using stratigraphic data as the verification basis. The multi-source geological exploration data is fused with the initial forward model, and different combinations of values ​​are set around the key parameters of the core structure. At the same time, the details of the deep strata occurrence are adjusted by combining well logging dip data to generate multiple sets of forward models with differentiated structural features, ensuring that the model can fully cover the possible features of complex structures. The multi-source geological exploration data includes the analysis results of complex structural models, actual drilling engineering data, and well logging data.

5. A method for VSP wavefield separation in complex structural regions according to any one of claims 1-4, characterized in that, The selection process for the target model includes: Forward modeling simulation is performed using multiple sets of the aforementioned forward modeling models, and an observation system consistent with the actual VSP observation is set up to obtain the simulated wavefield corresponding to each set of the aforementioned forward modeling models. Several reflection wave groups were selected for wave group feature comparison, and the reflection similarity between each simulated wave field and the actual wave field was calculated as the wave group feature similarity. Calculate the travel time difference between each simulated wavefield and the actual wavefield in different wave groups, and sum the absolute values ​​of the travel time differences in different wave groups to obtain the travel time deviation. The similarity of wave group features and travel time deviation between each simulated wavefield and the actual wavefield are weighted and summed to obtain the comprehensive matching degree between each simulated wavefield and the actual wavefield. The forward model corresponding to the simulated wavefield with the highest comprehensive matching degree is selected as the target model.

6. The method for VSP wavefield separation in complex structural regions according to claim 5, characterized in that, The refinement of the actual VSP wavefield using the simulated wavefield of the target model as a reference includes: Based on the simulated wave field corresponding to the target model, the propagation paths and wave field characteristics of the target wave and the interference wave are determined. Using the target wave in the simulated wave field as a reference, the target wave characteristics of the actual wave field are determined. The distribution characteristics of the target wave and the interference wave in the frequency-wavenumber domain are determined. Based on the distribution characteristics, an adaptive FK filter operator is designed. By dividing the FK domain boundary of the target wave and the interference wave, the actual wave field is filtered in the FK domain to complete the initial suppression of the strong interference wave. The target wave field is obtained by performing secondary processing on the FK domain filtered wave field using median filtering.

7. A VSP wavefield separation system for complex structural regions, characterized in that, include: The velocity acquisition module is configured to: acquire and process actual VSP observation data in complex structural areas using a target well-based zero-well-spacing VSP observation system to obtain VSP velocity; The model building module is configured to: based on the VSP velocity and combined with multi-source geological exploration data of the target well area, construct multiple sets of forward models with differentiated structural features; The matching and filtering module is configured to match the simulated wavefield obtained by each group of forward modeling models with the actual wavefield, and filter out the optimal forward modeling model as the target model. Furthermore, the separation module is configured to perform fine separation of the actual VSP wavefield using the simulated wavefield of the target model as a reference.

8. A VSP wavefield separation system for complex structural regions according to claim 7, characterized in that, The matching and filtering module includes: The forward modeling unit is configured to: perform forward modeling simulation using multiple sets of the forward modeling models, set up an observation system consistent with the actual VSP observations, and obtain the simulated wavefield corresponding to each set of the forward modeling models; The comparison and evaluation unit is configured to: select several reflection wave groups for wave group feature comparison, calculate the reflection similarity between each simulated wave field and the actual wave field as the wave group feature similarity; at the same time, calculate the travel time difference between each simulated wave field and the actual wave field in different wave groups, and sum the absolute values ​​of the travel time difference values ​​of different wave groups to obtain the travel time deviation. Furthermore, the target selection unit is configured to: perform a weighted summation of the wave group feature similarity and travel time deviation corresponding to each simulated wavefield and the actual wavefield to obtain the comprehensive matching degree between each simulated wavefield and the actual wavefield; and select the forward model corresponding to the simulated wavefield with the highest comprehensive matching degree as the target model.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the VSP wavefield separation method for complex structural regions as described in any one of claims 1-6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the VSP wavefield separation method for complex structural regions as described in any one of claims 1-6.

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