Dip-angle domain pre-stack time migration method, device and equipment for two-dimensional curved wide line

Abstract

The application provides a two-dimensional curved wide-line dip-angle domain stable-phase pre-stack time migration method, device and equipment, and relates to the technical field of seismic exploration data processing. The method comprises the following steps: obtaining original two-dimensional curved wide-line seismic data; determining common midpoint distribution and migration velocity field according to the original two-dimensional curved wide-line seismic data. For each common midpoint, the tangential azimuth of the common midpoint is calculated according to the common midpoint distribution and the migration velocity field, and a dip-angle gather distributed along the tangential azimuth is constructed. According to the dip-angle gather, the corresponding dip-angle domain Fresnel zone at each imaging point is determined. According to the dip-angle domain Fresnel zone, two-dimensional curved wide-line dip-angle domain stable-phase pre-stack time migration is performed, migration results under different migration distances are generated, and the migration results are stacked to generate a migration profile. The method is used to achieve the effect of effectively balancing imaging integrity and signal-to-noise ratio when pre-stack time migration processing of two-dimensional curved line data is performed.

Description

Technical Field

[0001] This application relates to the field of seismic exploration data processing technology, and more specifically, to a method, apparatus, and equipment for pre-stack time migration of a two-dimensional curved width line in the dip domain of a stable phase. Background Technology

[0002] Currently, in the field of seismic exploration, two-dimensional wide-line acquisition technology is widely used in complex work areas such as mountains and hills due to its ability to effectively adapt to complex surface and subsurface structural conditions. This technology avoids surface obstacles through flexible observation system design and significantly increases coverage by utilizing a wide-line observation system composed of multiple receiver lines, thereby effectively suppressing random noise and greatly improving the signal-to-noise ratio of the raw data. Therefore, two-dimensional wide-line acquisition can maximize the acquisition of valuable seismic information in complex areas while ensuring construction feasibility and cost control.

[0003] In existing technologies, pre-stack time migration processing for two-dimensional curved line data still mostly adopts the conventional Kirchhoff migration algorithm, whose migration aperture is usually set to a fixed value based on human experience or simply achieves "time variation".

[0004] However, the existing technology has obvious limitations: in order to take into account the imaging of steep diagonal structures, a larger aperture is often forced, which leads to the introduction of a large amount of offset noise and a decrease in the signal-to-noise ratio of the final profile; if the aperture is reduced in order to suppress noise, the effective signal of the steep diagonal angle is easily lost, making it difficult to achieve an effective balance between "imaging integrity" and "signal-to-noise ratio". Summary of the Invention

[0005] The purpose of this application is to provide a method, apparatus, and device for pre-stack time migration of two-dimensional curved line data in the tilt domain, which solves the above-mentioned problems existing in the prior art and can effectively balance imaging integrity and signal-to-noise ratio when processing pre-stack time migration data of two-dimensional curved lines.

[0006] Firstly, a method for pre-stack time migration of a two-dimensional curved line in the dip domain is provided, which may include:

[0007] Obtain the raw two-dimensional bend width line seismic data; determine the common center point distribution and migration velocity field based on the raw two-dimensional bend width line seismic data;

[0008] For each common center point, the tangential azimuth angle of the common center point is calculated based on the distribution of the common center points and the offset velocity field, and an inclination gather is constructed along the distribution of the tangential azimuth angle; wherein, each common center point corresponds to an imaging point, and the inclination gather is a dataset describing the imaging point;

[0009] Based on the tilt gather, determine the corresponding tilt domain Fresnel zone at each imaging point;

[0010] Based on the Fresnel zone of the tilt domain, perform a two-dimensional curved width line tilt domain steady phase pre-stack time migration to generate migration results at different offset distances, and then superimpose the migration results to generate a migration profile.

[0011] Secondly, a pre-stack time migration device for a two-dimensional curved line with an angle-domain stable phase is provided, the device comprising:

[0012] The first determining module is used to acquire the original two-dimensional bend width line seismic data; and to determine the common center point distribution and the migration velocity field based on the original two-dimensional bend width line seismic data.

[0013] The calculation module is used to calculate the tangential azimuth angle of each common center point based on the distribution of the common center points and the offset velocity field, and to construct an inclination gather along the tangential azimuth angle distribution; wherein, each common center point corresponds to an imaging point, and the inclination gather is a dataset describing the imaging point;

[0014] The second determining module is used to determine the Fresnel zone of the tilt domain at each imaging point based on the tilt gather.

[0015] The generation module is used to perform a two-dimensional curved width line dip angle domain steady phase pre-stack time migration according to the dip angle domain Fresnel zone, generate migration results at different migration distances, and superimpose the migration results to generate a migration profile.

[0016] Thirdly, an electronic device is provided, which includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0017] Memory, used to store computer programs;

[0018] When a processor executes a program stored in memory, it implements any of the steps described in the first aspect above.

[0019] Fourthly, a computer-readable storage medium is provided, wherein a computer program is stored therein, and when executed by a processor, the computer program implements the steps of any of the methods described in the first aspect above.

[0020] This application provides a dip-domain stable-phase pre-stack time migration method, apparatus, and device for two-dimensional bend-width lines. The method acquires raw two-dimensional bend-width line seismic data. Based on the raw two-dimensional bend-width line seismic data, it determines the common midpoint distribution and migration velocity field. For each common midpoint, based on the common midpoint distribution and migration velocity field, the tangential azimuth of the common midpoint is calculated, and a dip gather distributed along the tangential azimuth is constructed. Each common midpoint corresponds to an imaging point, and the dip gather is a dataset describing the imaging point. Based on the dip gather, the corresponding dip-domain Fresnel zone at each imaging point is determined. Based on the dip-domain Fresnel zone, a two-dimensional bend-width line dip-domain stable-phase pre-stack time migration is performed, generating migration results at different migration distances. The migration results are then superimposed to generate a migration profile. This scheme acquires raw 2D bend-width seismic data, determines the common midpoint distribution and migration velocity field; based on the raw 2D bend-width seismic data and migration velocity field, it constructs travel-time-dependent dip gathers along the tangential distribution of the common midpoints of the bend; based on the dip gathers, it extracts the corresponding dip domain Fresnel zones at each common midpoint; based on the Fresnel zone range, it performs 2D bend pre-stack time migration, generating migration results at different migration distances, ultimately forming a 2D bend stable-phase pre-stack time migration profile. Therefore, it solves the problem of selecting the optimal migration aperture based on Fresnel zone stacking in 2D bend-width seismic data pre-stack time migration imaging technology, and solves the problem of balancing steep-dipping structural imaging and signal-to-noise ratio in bend-width seismic data processing. Thus, it can achieve accurate estimation of dip gather construction and dip domain Fresnel zones in 2D bend-width seismic data, significantly suppressing migration noise while maintaining the integrity of steep-dipping structural imaging, and is well-suited to the irregular CMP distribution of bend-width observation systems, making it particularly suitable for seismic imaging processing in complex surface areas such as mountains and hills. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A flowchart illustrating a two-dimensional bend width line tilt domain stable phase pre-stack time migration method provided in an embodiment of this application;

[0023] Figure 2 A flowchart illustrating a two-dimensional bend width line tilt domain stable phase pre-stack time migration method provided in an embodiment of this application;

[0024] Figure 3A schematic diagram of tangential dip angle gather generation at the CMP point of a bend width line is provided for the example of this application;

[0025] Figure 4 A CMP point distribution diagram of actual curve width data provided in this application embodiment;

[0026] Figure 5 A pre-stack time-off local imaging profile of conventional commercial software for bend width line data provided in this application embodiment;

[0027] Figure 6 A tangential tilt angle gather for the CMP point of a bend width line provided in this application embodiment;

[0028] Figure 7 This application provides a local imaging profile of pre-stack time migration of two-dimensional bend width line dip angle domain stable phase for bend width line data in an embodiment of the present application.

[0029] Figure 8 A schematic diagram of the structure of a two-dimensional curved line tilt domain stable phase pre-stack time offset device provided in an embodiment of this application;

[0030] Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art. The words "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are only used to distinguish different components. The words "comprising" or "including," etc., mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but do not exclude other elements or objects. The words "connected," "coupled," or "connected," etc., are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] Currently, in the field of seismic exploration, two-dimensional wide-line acquisition technology is widely used in complex work areas such as mountains and hills due to its ability to effectively adapt to complex surface and subsurface structural conditions. This technology avoids surface obstacles through flexible observation system design and significantly increases coverage by utilizing a wide-line observation system composed of multiple receiver lines, thereby effectively suppressing random noise and greatly improving the signal-to-noise ratio of the raw data. Therefore, two-dimensional wide-line acquisition can maximize the acquisition of valuable seismic information in complex areas while ensuring construction feasibility and cost control.

[0033] In one example, pre-stack time migration processing for 2D curved line data still largely employs the conventional Kirchhoff migration algorithm, whose migration aperture is typically set to a fixed value based on manual experience or only achieves simple "time-varying". However, in existing technologies, this algorithm has significant limitations: to accommodate imaging of steep-dipping structures, a larger aperture is often forced, leading to the introduction of a large amount of migration noise and a decrease in the signal-to-noise ratio of the final profile; if the aperture is reduced to suppress noise, the effective signal of the steep dipping angle is easily lost, making it difficult to achieve an effective balance between "imaging integrity" and "signal-to-noise ratio".

[0034] In one example, the dip-domain phase-stabilized migration technique constructs a migration dip gather, visually identifying Fresnel zone regions where reflected wave energy is concentrated at each imaging point within the gather. It then superimposes energy only within these regions, achieving truly "space-varying" and "time-varying" optimal aperture selection, significantly improving migration imaging quality. However, applying this technique to curved data faces unique challenges: First, the common center point (CMP) acquired in curved data is not distributed along a straight line but is scattered across a banded area. Preprocessing is required to properly reposition it to the virtual CMP centerline, which is fundamental for velocity analysis and migration imaging. Second, curved survey lines result in variable azimuth angles on the shot-receiver ray paths, significantly different from the single azimuth angle of traditional two-dimensional straight survey lines. Therefore, the dip angle calculation formula based on the straight-line assumption cannot be directly applied. Existing three-dimensional phase-stabilized migration methods typically construct rectangular dip-domain Fresnel zones by generating a pair of orthogonal dip gathers (such as Inline and Crossline directions) and picking Fresnel zone boundaries separately. However, two-dimensional bending width line observation is essentially a "pseudo-three-dimensional" method. Directly applying three-dimensional methods not only makes the processing process complex and cumbersome, but also easily leads to a large energy blank area in the tilt gather, which is not conducive to the robust estimation of Fresnel zones and the improvement of actual imaging effect.

[0035] The tilt domain steady-state phase-over-time migration method for two-dimensional bend width lines provided in this application embodiment can be applied to electronic devices, terminal devices, tilt domain steady-state phase-over-time migration devices or equipment for two-dimensional bend width lines, or other devices or equipment that can execute this embodiment, and there are no limitations on this.

[0036] Terminal equipment can be user equipment (UE) such as mobile phones, smartphones, laptops, digital broadcast receivers, personal digital assistants (PDAs), and tablet computers (PADs), handheld devices, in-vehicle devices, wearable devices, computing devices or other processing devices connected to a wireless modem, mobile stations (MS), mobile terminals, etc. This terminal has the ability to communicate with one or more core networks via a radio access network (RAN).

[0037] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application. Furthermore, the embodiments and features in the embodiments of this application can be combined with each other without conflict.

[0038] Figure 1 This is a flowchart illustrating a pre-stack time migration method for a two-dimensional curved line with a stable phase in the tilt region, provided in an embodiment of this application. Figure 1 As shown, the method may include:

[0039] Step S101: Obtain the original two-dimensional flexural width seismic data; based on the original two-dimensional flexural width seismic data, determine the common center point distribution and the migration velocity field.

[0040] For example, raw two-dimensional 2D angular width line seismic data is acquired, and preprocessing is performed on the raw 2D angular width line seismic data before migration to obtain pre-stack 2D angular width line seismic data. Based on the pre-stack 2D angular width line seismic data, the common midpoint distribution and migration velocity field are determined. The common midpoint (hereinafter referred to as CMP point) is located on the Earth's surface.

[0041] Step S102: For each common center point, calculate the tangential azimuth angle of the common center point based on the common center point distribution and the offset velocity field, and construct an inclination gather along the tangential azimuth angle distribution; wherein, each common center point corresponds to an imaging point, and the inclination gather is a dataset describing the imaging point.

[0042] For example, for each common center point, the tangential azimuth angle of the common center point is calculated based on the common center point distribution and the offset velocity field, and a tilt gather is constructed along the tangential azimuth angle distribution. Each common center point corresponds to an imaging point located in the underground three-dimensional space, which is the location from which the reflected signal is to be determined; the tilt gather is a dataset describing the imaging point.

[0043] Step S103: Determine the Fresnel zone corresponding to each imaging point based on the tilt angle gather.

[0044] For example, firstly, based on preset indicators, the steady-state point of the tilt channel is determined. Starting from the steady-state point, the boundary where the energy decays to the threshold is searched to the left and right, respectively, as the left and right boundaries of the tilt domain Fresnel zone. The left and right boundaries of the tilt domain Fresnel zone at the steady-state point are extended to each imaging point by interpolation to obtain the tilt domain Fresnel zone at each imaging point.

[0045] Step S104: Based on the Fresnel zone of the dip angle domain, perform a two-dimensional curved width line dip angle domain steady phase pre-stack time migration to generate migration results at different migration distances, and superimpose the migration results to generate a migration profile.

[0046] For example, the original two-dimensional slant width seismic data is divided into multiple groups according to a preset offset interval. Based on the dip domain Fresnel zone at each imaging point and the multiple groups, a two-dimensional slant width seismic data stable phase pre-stack time migration calculation is performed to generate a migration gather; wherein the migration gather includes migration results at different offsets. Finally, the migration results at different offsets are stacked to generate a migration profile.

[0047] The method provided in this application embodiment acquires raw two-dimensional bend-width seismic data; based on the raw two-dimensional bend-width seismic data, it determines the common midpoint distribution and migration velocity field. For each common midpoint, based on the common midpoint distribution and migration velocity field, the tangential azimuth of the common midpoint is calculated, and a dip gather distributed along the tangential azimuth is constructed; wherein, each common midpoint corresponds to an imaging point, and the dip gather is a dataset describing the imaging point. Based on the dip gather, the dip domain Fresnel zone corresponding to each imaging point is determined. Based on the dip domain Fresnel zone, a two-dimensional bend-width dip domain stable phase pre-stack time migration is performed, generating migration results at different migration distances, and the migration results are superimposed to generate a migration profile. This scheme acquires raw 2D bend-width seismic data, determines the common midpoint distribution and migration velocity field; based on the raw 2D bend-width seismic data and migration velocity field, it constructs travel-time-dependent dip gathers along the tangential distribution of the common midpoints of the bend; based on the dip gathers, it extracts the corresponding dip domain Fresnel zones at each common midpoint; based on the Fresnel zone range, it performs 2D bend pre-stack time migration, generating migration results at different migration distances, ultimately forming a 2D bend stable-phase pre-stack time migration profile. Therefore, it solves the problem of selecting the optimal migration aperture based on Fresnel zone stacking in 2D bend-width seismic data pre-stack time migration imaging technology, and solves the problem of balancing steep-dipping structural imaging and signal-to-noise ratio in bend-width seismic data processing. Thus, it can achieve accurate estimation of dip gather construction and dip domain Fresnel zones in 2D bend-width seismic data, significantly suppressing migration noise while maintaining the integrity of steep-dipping structural imaging, and is well-suited to the irregular CMP distribution of bend-width observation systems, making it particularly suitable for seismic imaging processing in complex surface areas such as mountains and hills.

[0048] Figure 2 A flowchart illustrating a two-dimensional bend width line dip-domain pre-stack time migration method provided in this application is shown below. Figure 2 As shown, in this embodiment... Figure 1 Based on the embodiments, the method is described in detail below, and the method includes:

[0049] Step S201: Obtain the original two-dimensional flexural width seismic data; based on the original two-dimensional flexural width seismic data, determine the common center point distribution and the migration velocity field.

[0050] In one example, S201 includes: acquiring raw two-dimensional 2D flexural seismic data; preprocessing the raw two-dimensional flexural seismic data to obtain pre-stack two-dimensional flexural seismic data; determining the common midpoint distribution based on the raw two-dimensional flexural seismic data; wherein the common midpoint distribution includes multiple common midpoints; extracting common midpoint gathers from the pre-stack two-dimensional flexural seismic data at preset intervals; performing velocity iteration processing on the extracted common midpoint gathers to generate a migration velocity field.

[0051] In one example, “preprocessing the original two-dimensional slant width seismic data to obtain two-dimensional slant width prestack seismic data” includes: if the preprocessing is defined by the observation system, then calculating the common midpoint centerline based on the original two-dimensional slant width seismic data; in response to manual intervention operations on the common midpoint centerline, generating an adjusted common midpoint centerline; wherein the adjusted common midpoint centerline coincides with the center of the reflected wave scatter points in the original two-dimensional slant width seismic data.

[0052] For example, raw 2D flexural line seismic data is acquired and preprocessed. The preprocessing workflow for 2D flexural line pre-stack seismic data mainly includes raw seismic data decoding, observation system definition, static correction, pre-stack denoising, amplitude compensation, deconvolution, and velocity analysis. Through the above preprocessing, 2D flexural line pre-stack seismic data suitable for Kirchhoff time migration can be obtained. Then, based on the raw 2D flexural line seismic data, the CMP point distribution is determined, which includes multiple CMP points. At preset intervals, common center point gathers are extracted from the 2D flexural line pre-stack seismic data. Velocity iteration processing is performed on the extracted CMP point gathers to generate a migration velocity field.

[0053] Optionally, compared to 2D straight-line seismic data, the key to the pre-processing workflow of 2D curved-width-line pre-stack seismic data lies in the proper positioning of the CMP points along the curved-width line. The processing first automatically calculates the CMP centerline, then manually intervenes in sections with significant line curvature to adjust the CMP centerline orientation, ensuring a better match between the CMP centerline and the reflected wave scatter points, thus laying the geometric foundation for subsequent processing. In the velocity analysis stage, a portion of the curved-width-line CMP point gathers are extracted at preset intervals. Conventional dynamic correction velocity picking and smoothing are performed on the extracted gathers to establish an initial migration velocity field. Subsequently, conventional pre-stack time migration techniques are used to iteratively update the migration velocity, gradually optimizing and obtaining the final migration velocity field.

[0054] Step S202: Based on the original two-dimensional curved-width seismic data, determine the offset gather characteristics at each common center point; based on the offset gather characteristics at each common center point, determine the stretching shear parameters.

[0055] For example, based on the original two-dimensional curve width line seismic data, the offset gather characteristics at each CMP point are determined. Based on the offset gather characteristics at each CMP point, the stretching cut parameters are reasonably determined, laying the foundation for subsequent dip domain stable phase migration processing.

[0056] Step S203: For each common center point, calculate the tangential azimuth angle of the common center point based on the common center point distribution and the offset velocity field, and construct an inclination gather along the tangential azimuth angle distribution; wherein, each common center point corresponds to an imaging point, and the inclination gather is a dataset describing the imaging point.

[0057] In one example, S203 includes: for each common center point, calculating the tangential azimuth at the current common center point based on the coordinates of the common center points adjacent to the current common center point in the common center point distribution; calculating the dip angle of each imaging point along the tangential azimuth based on the migration velocity field and the seismic traces in the original two-dimensional curved-width seismic data; and calculating the migration result of the seismic traces at the imaging point; and sorting, arranging and stacking the migration results based on the dip angle to construct a dip angle gather distributed along the tangential azimuth.

[0058] For example, based on the migration velocity field and seismic data, a dip gather with travel time correlation is constructed along the tangential distribution of the CMP point on the curve. Figure 3 A schematic diagram of tangential dip angle gather generation at the CMP point of a bend width line is provided as an example of this application. Figure 3 As shown, 0 is the origin, the curved solid line is the CMP line, points S and G are the shot and receiver points, point I is the imaging point, point M is the projection of point I onto the ground, and the straight line... The tangent to the CMP line at point M. It is a straight line The plane relative to the azimuth angle of the x-axis For the virtual reflection interface corresponding to the shot-receiver points S and G, the plane It is a straight line And the vertical plane defined by MI, the straight line For plane With plane The angle, , planes The apparent tilt angles in the x and y directions, For plane At an azimuth angle relative to the x-axis The apparent tilt angle in the direction, that is, the tangential apparent tilt angle at the CMP point of the curve width line. They can be expressed as the following formula (1), It can be expressed as the following formula (2):

[0059] ,

[0060] in, Let S be the surface coordinates of the shot point. Let G be the surface coordinates of the receiver point. Let be the coordinates of the i-th CMP point (M point). Let I be the coordinates of the imaging point. Let be the stacking velocity of imaging point I, and T be the vertical one-way travel time of imaging point I. , These are the travel times from the shot point S and the receiver point G to the imaging point I, respectively. , They can be represented as follows:

[0061] ,

[0062] flat At an azimuth angle relative to the x-axis Inclination angle in direction It can be expressed as the following formula (5):

[0063] —(5)

[0064] Among them, azimuth angle The range of values ​​is It can be expressed as the following formula (6):

[0065] —(6)

[0066] in, and The coordinates of the (i+1)th and (i-1)th CMP points are respectively. Under the curve width line observation system, before calculating the dip angle gather along the tangential direction of the CMP point, it is necessary to calculate the tangential azimuth angle at each CMP point according to equation (6).

[0067] Based on equations (1)-(5), under the curve width observation system, the dip angle gather along the tangential direction of the CMP point can be expressed as the following formula (7):

[0068] —(7)

[0069] in, For the i-th CMP point Tangential angle gathers, This represents the total number of traces used in two-dimensional curved-width line stable-phase pre-stack time-migrating seismic data. This represents the semi-derivative of the m-th seismic trace.

[0070] In the curved width line observation system, when calculating the dip gather along the tangent of the CMP point, for any seismic trace in the pre-stack seismic data, firstly, according to the dip calculation formula (5), the dip angle along the tangent of the CMP point is calculated at any imaging point, and at the same time, the offset result of the seismic trace at the imaging point is calculated; secondly, according to the formula (7), the seismic trace is cyclically processed, and according to the dip angle interval along the tangent of the CMP point calculated above, regardless of the size of the data offset distance, the above offset results are sorted, arranged and superimposed to obtain the dip gather along the tangent of the CMP point.

[0071] Step S204: Determine the Fresnel zone corresponding to each imaging point based on the tilt angle gather.

[0072] In one example, S204 includes: identifying a stable phase point in the tilt channel set based on a preset index; starting from the stable phase point, searching for the boundary where the energy decays to a threshold to the left and right sides, respectively, as the left and right boundaries of the tilt domain Fresnel zone; extending the left and right boundaries of the tilt domain Fresnel zone at the stable phase point to each imaging point through interpolation to obtain the tilt domain Fresnel zone at each imaging point.

[0073] In one example, “Identifying stable phase points in the tilt channel based on preset indicators” includes: if the flatness index and amplitude ratio index of the determined imaging point are both greater than preset thresholds, the imaging point is determined to be a stable phase point.

[0074] For example, in a bend-width line observation system, the dip angle in the dip angle gather along the tangent of the CMP point is not the true formation dip angle, but a dip angle related to travel time. However, the reflection wave phase axis exhibits a similar downward convex curve shape in both the travel-related dip angle gather and the true dip angle gather, and the travel-related dip angle of the reflection interface corresponds to the vertex of the bend phase axis. The stacking result of the dip-domain migration gather along the dip direction is the Kirchhoff stack migration result. From the perspective of stacking, this vertex is the stable phase point, and the neighborhood of the vertex is the dip-domain Fresnel zone. Therefore, before determining the dip-domain Fresnel zone, it is necessary to first obtain the target CMP point, i.e., the stable phase point.

[0075] The first step, based on preset indices, is to determine some potential stable phase point values ​​of in-phase axes by utilizing the relationship between the tilt angle gather along the tangential direction of the CMP point and the offset profile. Two indices are first defined regarding the Fresnel zone in the tilt angle domain: flatness index and amplitude ratio index. The flatness index can be expressed as the following formula (8):

[0076] —(8)

[0077] In equation (8), D represents the tilt angle convergence imaging point I. Fresnel bands for stable phase points, For the imaging point I, the first Vertical one-way travel time corresponding to each time sampling point. Indicates the first inclination angle concentration Tao Zhong Yi The maximum amplitude value (positive or negative) within a small time window centered on the CMP point. In the dip zone set along the tangential direction of the CMP point, the left and right boundaries of the dip zone Fresnel zone D can be approximately expressed as the following formula (9):

[0078] —(9)

[0079] In equation (9), Let I be the left and right boundaries of the Fresnel zone boundary in the tilt region of the imaging point I. The dominant frequency of the seismic data. The amplitude ratio index can be expressed as follows (10):

[0080] —(10)

[0081] In equation (10), Indicates the tilt channel convergence imaging point I. The amplitude value of the Dao, This represents the amplitude value of the offset profile at the imaging point.

[0082] For all time-series sampling points of the cyclic CMP points, if the flatness index of the sampling points... Amplitude ratio index If all values ​​are greater than a preset threshold (for example, a preset threshold of 0.8, this is just an example), then the sampling point is a potential stable phase point, and the potential stable phase point angle value of the sampling point is... If the first If multiple potential stable phase points exist for a given time sampling point, then the average value of all potential stable phase points is taken as the final stable phase point angle value. Finally, the time-depth sequence of the in-phase axis of the CMP is obtained. and the corresponding stable phase point sequence ,in , The number of in-phase axes of the picked-up reflected waves.

[0083] The second step involves searching for boundaries where energy decays to a threshold on both sides of the target CMP point, starting from the stable phase point, based on the tilt gather at the target CMP point and the corresponding stable phase point sequence. These boundaries are then used as the left and right boundaries of the tilt domain Fresnel zone, respectively. The tilt domain Fresnel zone at the target CMP point is calculated, which is the tilt domain Fresnel zone of the imaging point corresponding to the target CMP point. Optionally, it is not necessary to directly calculate the left and right boundaries of the tilt domain Fresnel zone using Equation (9) based on the stable phase point sequence. This is because the implementation of two-dimensional curved-width tilt domain stable phase pre-stack time migration requires imaging not only the reflected waves within the Fresnel zone but also the diffraction waves generated by diffracting bodies such as faults, beaded structures, and cracks. Otherwise, the faults and other features on the migration profile will be poorly depicted. Therefore, on the tilt gather along the tangent of the CMP point, starting from the stable phase point, the corresponding left and right boundaries of the Fresnel zone are obtained by searching along the left and right sides respectively.

[0084] make Indicates the inclination angle range ,here Indicates the stable phase point, Let k represent the angle sampling interval of the tilt gather, and k be an integer search step size. The left and right boundaries of the Fresnel zone in the tilt domain are searched using equation (11):

[0085] —(11)

[0086] in, Indicates the right boundary of the Fresnel zone. Indicates the left boundary of the Fresnel zone. For the imaging point I, the first Vertical one-way travel time corresponding to each time sampling point For the angle of inclination, the first Daozhongdi The amplitude values ​​corresponding to each time sampling point. The left and right boundaries of the Fresnel zone in the tilt domain determined by the energy search method of Equation (11) not only include the reflected wave energy within the Fresnel zone concentrated in the tilt channel, but also the diffracted wave energy of the straight diffracted wave concentrated in the tilt channel, which is beneficial for imaging diffracted bodies such as faults, beaded structures, and cracks.

[0087] The third step involves linearly interpolating and smoothing the Fresnel zone boundaries of the tilt gather at the target CMP point obtained in the second step along the time-depth direction and the CMP survey line direction, respectively, to obtain the left and right boundaries of the tilt domain Fresnel zone for all imaging points.

[0088] Step S205: Based on the Fresnel zone of the dip angle domain, perform a two-dimensional curved width line dip angle domain steady phase pre-stack time migration to generate migration results at different migration distances, and superimpose the migration results to generate a migration profile.

[0089] In one example, S205 includes: dividing the original two-dimensional wavy-width seismic data into multiple groups according to a preset offset interval; calculating the dip domain Fresnel zone weighting coefficient for each imaging point based on the dip domain Fresnel zone at each imaging point; performing two-dimensional wavy-width seismic data stable phase pre-stack time migration calculation based on the dip domain Fresnel zone weighting coefficient and the grouping to generate a migration gather; wherein the migration gather includes migration results at different offsets; and stacking the migration results at different offsets to generate a migration profile.

[0090] In one example, S205 includes: performing a two-dimensional curved width line dip domain steady phase pre-stack time migration based on the dip domain Fresnel band, generating migration results at different migration distances; and removing the stretch distortion portion in the migration results based on the stretch cut-off parameters, and superimposing the removed migration results to generate a migration profile.

[0091] For example, in order to facilitate the formation of CRP (Common Reflection Point) migration gathers for pre-stack time migration of two-dimensional curved lines, the pre-stack seismic data of two-dimensional curved lines are first grouped according to a preset offset interval to obtain multiple groups. The two-dimensional curved line stable phase pre-stack time migration can be expressed as the following formula (12):

[0092] -(12),

[0093] in, Let H be the i-th CMP point, and H be the offset distance. This can be expressed as: , For imaging points The offset magnitude corresponding to the offset distance H, This represents the total number of traces used in two-dimensional curved-width line stable-phase pre-stack time-migrating seismic data. These are the amplitude-preserving weighting coefficients for two-dimensional pre-stack time migration. This represents the semi-derivative of the m-th seismic trace. The Fresnel zone weighting coefficients in the tilt domain can be calculated based on the Fresnel zone in the tilt domain at each imaging point. The Fresnel zone weighting coefficients in the tilt domain are expressed as follows (13):

[0094] -(13),

[0095] in, The inclination angle of the tangential azimuth at each imaging point along the CMP line is given by equation (5). and These are the left and right boundaries of the Fresnel zone in the tilt region at each imaging point, in sequence. This represents the width of the tilt attenuation band.

[0096] Based on the Fresnel zone weighting coefficients in the tilt domain and the grouping, a two-dimensional curved-width line pre-stack time migration is performed according to Equation (13) to obtain the migration gather of the imaging point (CRP). The migration gather includes migration results at different offset distances. During or after the migration, the stretched and distorted parts of the reflected wave phase axis on the migration gather need to be removed. Then, the migration results at different offset distances are superimposed along the offset distance to obtain the two-dimensional curved-width line pre-stack time migration profile.

[0097] The method provided in this application embodiment acquires raw two-dimensional bend-width seismic data; determines the common midpoint distribution and migration velocity field based on the raw two-dimensional bend-width seismic data; determines the migration distance gather characteristics at each common midpoint based on the raw two-dimensional bend-width seismic data; and determines the stretch cut parameters based on the migration distance gather characteristics at each common midpoint. For each common midpoint, the tangential azimuth angle of the common midpoint is calculated based on the common midpoint distribution and migration velocity field, and a dip angle gather distributed along the tangential azimuth angle is constructed; wherein each common midpoint corresponds to an imaging point, and the dip angle gather is a dataset describing the imaging point. Based on the dip angle gather, the corresponding dip-domain Fresnel zone at each imaging point is determined. Based on the dip-domain Fresnel zone, a two-dimensional bend-width dip-domain stable phase pre-stack time migration is performed to generate migration results at different migration distances, and the migration results are superimposed to generate a migration profile. Therefore, this method solves the problem of selecting the optimal migration aperture based on Fresnel zone stacking in pre-stack time migration imaging technology for 2D wavy seismic data. It also addresses issues in wavy seismic data processing such as the difficulty in balancing steep-dipping structural imaging with signal-to-noise ratio, inaccurate dip-domain Fresnel zone estimation, and low imaging accuracy due to irregular observation systems. Consequently, it enables the construction of dip gathers and accurate estimation of dip-domain Fresnel zones for 2D wavy seismic data, significantly suppressing migration noise while maintaining the integrity of steep-dipping structural imaging, and effectively adapting to the irregular CMP distribution of wavy seismic observation systems. This method is particularly suitable for seismic imaging processing in complex surface areas such as mountains and hills.

[0098] In one example, based on the above embodiments, this application uses two-dimensional bend width line data acquired on a loess plateau as an example to illustrate the application effect of the dip-domain stable phase pre-stack time migration method for this two-dimensional bend width line. The data, after undergoing the pre-processing workflow of two-dimensional bend width line pre-stack seismic data migration, has a total data volume of approximately 1.1 GB, a maximum migration distance of 3903 meters, a data sampling interval of 2 milliseconds, and 2501 data sampling points. Figure 4 A CMP point distribution map of actual bend width line data provided in this application embodiment, such as... Figure 4 As shown, the CMP points are distributed along a curved line. This distribution of CMP points corresponds to... Figure 3 Medium-curved solid line (i.e., CMP line). Figure 5 A pre-stack time-migrated local imaging profile of existing conventional commercial software for bending width line data provided in this application embodiment, such as... Figure 5 As shown, due to the influence of various interference waves, the seismic data of the Loess Plateau mountainous terrain has poor data quality. Figure 5 The imaging profile has a low signal-to-noise ratio, and commercial software migration can only provide a large, laterally invariant migration aperture based on geological experience, which introduces a lot of migration noise. Figure 6This application provides a tangential tilt angle gather for the CMP point of a bend width line. Figure 5 Data at a point on the horizontal axis, such as Figure 6 As shown, the two white lines represent the boundaries of the Fresnel zone in the tilt region at this CMP. Figure 7 This application provides a local imaging profile of pre-stack time migration of two-dimensional bend width line dip angle domain steady phase data, as provided in an embodiment of the present application. Figure 5 compared to, Figure 7 While maintaining correct imaging construction, the signal-to-noise ratio is significantly improved, and the continuity of the phase axis is enhanced. Therefore, the tilt-domain steady-state pre-stack time migration method for two-dimensional curved lines provided in this application can solve the problem of optimal migration aperture selection based on tilt-domain Fresnel zone stacking, and can significantly improve the signal-to-noise ratio of the migration profile while maintaining correct imaging construction.

[0099] Corresponding to the above method, this application also provides a time migration device for pre-stack phase stability in the tilt region of a two-dimensional curved width line, such as... Figure 8 As shown, the device includes:

[0100] The first determining module 41 is used to acquire the original two-dimensional bend width line seismic data; and to determine the common center point distribution and the offset velocity field based on the original two-dimensional bend width line seismic data.

[0101] The calculation module 42 is used to calculate the tangential azimuth angle of each common center point based on the distribution of the common center points and the offset velocity field, and to construct an inclination gather distributed along the tangential azimuth angle; wherein, each common center point corresponds to an imaging point, and the inclination gather is a dataset describing the imaging point;

[0102] The second determining module 43 is used to determine the Fresnel zone corresponding to each imaging point based on the tilt angle gather.

[0103] The generation module 44 is used to perform a two-dimensional curved width line dip angle domain steady phase pre-stack time migration according to the dip angle domain Fresnel zone, generate migration results at different migration distances, and superimpose the migration results to generate a migration profile.

[0104] The functions of each functional unit of the two-dimensional curved line tilt domain stable phase pre-overlap time migration device provided in the above embodiments of this application can be implemented through the above-described method steps. Therefore, the specific working process and beneficial effects of each unit in the two-dimensional curved line tilt domain stable phase pre-overlap time migration device provided in the embodiments of this application will not be repeated here.

[0105] This application also provides an electronic device, such as... Figure 9As shown, it includes a processor 510, a communication interface 520, a memory 530, and a communication bus 540, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other through the communication bus 540.

[0106] Memory 530 is used to store computer programs;

[0107] The processor 510 performs the above steps when executing the program stored in the memory 530.

[0108] The communication bus mentioned above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0109] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0110] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0111] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0112] The implementation methods and beneficial effects of the various components of the electronic device in the above embodiments for solving the problem can be found in [reference needed]. Figure 1 The steps in the illustrated embodiments are used to implement the electronic device. Therefore, the specific working process and beneficial effects of the electronic device provided in this application will not be repeated here.

[0113] In another embodiment provided in this application, a computer-readable storage medium is also provided, which stores instructions that, when executed on a computer, cause the computer to perform the pre-stack time migration method for the tilt domain of the two-dimensional curved width line described in any of the above embodiments.

[0114] In another embodiment provided in this application, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to execute the pre-stack time migration method for the tilt domain of two-dimensional curved width lines as described in any of the above embodiments.

[0115] Those skilled in the art will understand that the embodiments in this application can be provided as methods, systems, or computer program products. Therefore, the embodiments in this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the embodiments in this application can take the form of a computer program product implemented 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.

[0116] This application describes embodiments of methods, apparatus (systems), and computer program products according to embodiments of this application with reference to flowchart illustrations and / or block diagrams. 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 illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0117] 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.

[0118] 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.

[0119] Although preferred embodiments have been described in this application, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of this application.

[0120] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims in this application and their equivalents, then this application also intends to include these modifications and variations.

Claims

1. A method for time migration before phase stacking in the dip region of a two-dimensional curved line, characterized in that, The method includes: Obtain the raw two-dimensional bend width line seismic data; determine the common center point distribution and migration velocity field based on the raw two-dimensional bend width line seismic data; For each common center point, the tangential azimuth angle of the common center point is calculated based on the distribution of the common center points and the offset velocity field, and an inclination gather is constructed along the distribution of the tangential azimuth angle; wherein, each common center point corresponds to an imaging point, and the inclination gather is a dataset describing the imaging point; Based on the tilt gather, determine the corresponding tilt domain Fresnel zone at each imaging point; Based on the Fresnel zone of the dip angle domain, perform a two-dimensional curved width line dip angle domain steady phase pre-stack time migration to generate migration results at different migration distances, and superimpose the migration results to generate a migration profile; For each common midpoint, based on the common midpoint distribution and the offset velocity field, the tangential azimuth angle of the common midpoint is calculated, and an inclination gather along the tangential azimuth angle distribution is constructed, including: For each common center point, the tangential azimuth angle at the current common center point is calculated based on the coordinates of the common center points adjacent to the current common center point in the distribution of common center points. Based on the migration velocity field and the seismic traces in the original two-dimensional curved line seismic data, the dip angle of each imaging point along the tangential azimuth is calculated; and the migration result of the seismic trace at that imaging point is calculated. Based on the tilt angle, the offset results are sorted, arranged, and superimposed to construct a tilt angle gather distributed along the tangential azimuth angle; Based on the tilt gather, determine the corresponding tilt-domain Fresnel zone at each imaging point, including: Based on preset indicators, stable phase points are identified in the tilt track cluster; Starting from the stable phase point, search for the boundaries where the energy decays to the threshold to the left and right, respectively, which are taken as the left and right boundaries of the Fresnel zone in the tilt domain; The left and right boundaries of the tilt domain Fresnel zone at the stable phase point are extended to each imaging point by interpolation to obtain the tilt domain Fresnel zone at each imaging point.

2. The method as described in claim 1, characterized in that, Based on preset indicators, the stable phase point is identified in the tilt track cluster, including: If both the flatness index and amplitude ratio index of the imaging point are greater than the preset threshold, the imaging point is determined to be a stable phase point.

3. The method as described in claim 1, characterized in that, Based on the Fresnel zone in the dip angle domain, a two-dimensional curved width line dip angle domain pre-stack time migration is performed to generate migration results at different migration distances. These migration results are then superimposed to generate a migration profile, including: The original two-dimensional curved line seismic data is divided into multiple groups according to a preset offset interval; Calculate the tilt domain Fresnel zone weighting coefficients for each imaging point based on the tilt domain Fresnel zone at each imaging point. Based on the dip angle domain Fresnel zone weighting coefficients and the grouping, a two-dimensional bend width line stable phase pre-stack time migration calculation is performed to generate a migration gather; wherein, the migration gather includes migration results with different offset distances; The offset results at different offset distances are superimposed to generate an offset profile.

4. The method as described in claim 1, characterized in that, Acquire raw two-dimensional 2D flexural width seismic data; based on the raw two-dimensional flexural width seismic data, determine the common midpoint distribution and migration velocity field, including: Obtain raw two-dimensional bend width line seismic data; preprocess the raw two-dimensional bend width line seismic data to obtain two-dimensional bend width line prestack seismic data. Based on the original two-dimensional curve width line seismic data, the common midpoint distribution is determined; wherein, the common midpoint distribution includes multiple common midpoints; According to a preset interval, common midpoint gathers are extracted from the two-dimensional curved-width pre-stack seismic data; velocity iteration processing is performed on the extracted common midpoint gathers to generate a migration velocity field.

5. The method as described in claim 4, characterized in that, The original two-dimensional bend width seismic data is preprocessed to obtain two-dimensional bend width pre-stack seismic data, including: If the preprocessing is defined by the observation system, then the common centerline is calculated based on the original two-dimensional curve width line seismic data; In response to manual intervention on the common centerline, an adjusted common centerline is generated; wherein the adjusted common centerline coincides with the center of the reflected wave scatter points in the original two-dimensional curved-width seismic data.

6. The method according to any one of claims 1-5, characterized in that, After acquiring the raw two-dimensional curve width seismic data, the method further includes: Based on the original two-dimensional curved-width seismic data, the offset gather characteristics at each common center point are determined; based on the offset gather characteristics at each common center point, the stretching shear parameters are determined. Based on the Fresnel zone in the dip angle domain, a two-dimensional curved width line dip angle domain pre-stack time migration is performed to generate migration results at different migration distances. These migration results are then superimposed to generate a migration profile, including: Based on the Fresnel zone of the tilt domain, perform a two-dimensional curved line tilt domain steady phase pre-stack time migration to generate migration results at different offset distances; Based on the stretching cut parameters, the stretching distortion portion in the offset result is cut off, and the offset result after cut-off is superimposed to generate an offset profile.

7. A time migration device for pre-stacked phase stability in the tilt region of a two-dimensional curved line, characterized in that, The device includes: The first determining module is used to acquire the original two-dimensional bend width line seismic data; and to determine the common center point distribution and the migration velocity field based on the original two-dimensional bend width line seismic data. The calculation module is used to calculate the tangential azimuth angle of each common center point based on the distribution of the common center points and the offset velocity field, and to construct an inclination gather along the tangential azimuth angle distribution; wherein, each common center point corresponds to an imaging point, and the inclination gather is a dataset describing the imaging point; The second determining module is used to determine the Fresnel zone of the tilt domain at each imaging point based on the tilt gather. The generation module is used to perform a two-dimensional curved width line dip domain steady phase pre-stack time migration based on the dip domain Fresnel zone, generate migration results at different migration distances, and superimpose the migration results to generate a migration profile. The calculation module includes: For each common center point, the tangential azimuth angle at the current common center point is calculated based on the coordinates of the common center points adjacent to the current common center point in the distribution of common center points. Based on the migration velocity field and the seismic traces in the original two-dimensional curved line seismic data, the dip angle of each imaging point along the tangential azimuth is calculated; and the migration result of the seismic trace at that imaging point is calculated. Based on the tilt angle, the offset results are sorted, arranged, and superimposed to construct a tilt angle gather distributed along the tangential azimuth angle; The second determining module includes: Based on preset indicators, stable phase points are identified in the tilt track cluster; Starting from the stable phase point, search for the boundaries where the energy decays to the threshold to the left and right, respectively, which are taken as the left and right boundaries of the Fresnel zone in the tilt domain; The left and right boundaries of the tilt domain Fresnel zone at the stable phase point are extended to each imaging point by interpolation to obtain the tilt domain Fresnel zone at each imaging point.

8. An electronic device, characterized in that, The electronic device includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, when executing a program stored in memory, implements the method of any one of claims 1-6.

Images