CN113341456B

CN113341456B - Seismic migration method and device based on irregular grid and electronic equipment

Info

Publication number: CN113341456B
Application number: CN202110774494.9A
Authority: CN
Inventors: 仇楚钧; 杨顶辉
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2021-07-08
Filing date: 2021-07-08
Publication date: 2024-02-02
Anticipated expiration: 2041-07-08
Also published as: CN113341456A

Abstract

The embodiment of the invention discloses a seismic migration method and device based on an irregular grid and electronic equipment, wherein the method comprises the following steps: determining a target background speed parameter of each irregular grid in a target imaging area based on interpolation and the background speed parameter of the target imaging area; determining an accompanying wave field of the target imaging area based on the target background speed parameter, the first slowness disturbance, the medium density, the background wave field and the observed wave field data of the irregular grid by a discontinuous finite element method; determining a first gradient for updating the first slowness disturbance based on the satellite wave field and the background wave field; updating the first slowness disturbance based on a preset gradient descent method and the first gradient to obtain a target slowness disturbance; and performing offset imaging on the target imaging area based on the target slowness disturbance. By the method, imaging accuracy of a target imaging area can be improved.

Description

Seismic migration method and device based on irregular grid and electronic equipment

Technical Field

The present invention relates to the field of computer technologies, and in particular, to a seismic migration method and apparatus based on an irregular grid, and an electronic device.

Background

Seismic exploration methods are an important means of human acquisition of subsurface space information, where seismic migration imaging is a key step in seismic data processing. The offset can accurately return the reflected wave, has the characteristics of high imaging precision and wide adaptability, and can intuitively display the real form of the underground structure.

At present, an imaging area with complex terrain structure and large surface fluctuation can be subjected to offset imaging by a least square reverse time offset method based on an inversion idea through regular grid subdivision.

However, when an imaging region with a large processed surface fluctuation is subjected to offset imaging, the trapezoidal approximation causes scattered waves to be generated, which affect the imaging, resulting in poor imaging accuracy of the imaging region.

Disclosure of Invention

The embodiment of the invention aims to provide an earthquake migration method and device based on an irregular grid and electronic equipment, so as to solve the problem of poor imaging accuracy in the prior art when an imaging area with a complex structure is subjected to migration imaging.

In order to solve the technical problems, the embodiment of the invention is realized as follows:

in a first aspect, an embodiment of the present invention provides a seismic migration method based on an irregular grid, where the method includes:

determining a target background speed parameter of each irregular grid in a target imaging area based on interpolation and the background speed parameter of the target imaging area;

determining an accompanying wave field of the target imaging area based on the target background speed parameter, the first slowness disturbance, the medium density, the background wave field and the observed wave field data of the irregular grid by a discontinuous finite element method;

determining a first gradient for updating the first slowness disturbance based on the satellite wave field and the background wave field;

updating the first slowness disturbance based on a preset gradient descent method and the first gradient to obtain a target slowness disturbance;

and performing offset imaging on the target imaging area based on the target slowness disturbance.

Optionally, the determining the target background velocity parameter of each irregular grid in the target imaging region based on interpolation and the background velocity parameter of the target imaging region includes:

Based on a preset relevant point selection rule, four relevant points corresponding to the central points of the irregular grid are selected;

acquiring position coordinates and background speed parameters of each relevant point in the depth and horizontal directions;

substituting the position coordinates of each of the four related points in the depth and horizontal directions and the background speed parameters into a formula

Obtaining a background velocity parameter of a center point of the irregular grid, wherein,c, a background speed parameter for the central point of the irregular grid _i,j 、c _i+1,j 、c _i,j+1 And c _i+1,j+1 Background velocity parameters of the four related points, (x) _i ，z _j )、(x _i+1 ，z _j )、(x _i ，z _j+1 ) And (x) _i+1 ，z _j+1 ) The position coordinates of the four related points are respectively;

and determining the background speed parameter of the central point of the irregular grid as the target background speed parameter of the irregular grid.

Optionally, the determining, by the intermittent finite element method, the concomitant wavefield of the target imaging region based on the target background velocity parameter, the first slowness disturbance, the medium density, the background wavefield and the observed wavefield data of the irregular grid, includes:

determining the background slowness of the irregular grid based on the target background speed parameter of the irregular grid;

Acquiring position coordinates of the central point of each irregular grid in the depth and horizontal directions;

determining a disturbance wave field of the target imaging area based on the background slowness of the irregular grid, the position coordinates of the center points of the irregular grid, the first slowness disturbance, the medium density and the background wave field by the intermittent finite element method;

a concomitant wavefield of the target imaging region is determined based on the position coordinates of the irregular grid center points, the perturbed wavefield, the medium density, the observed wavefield data.

Optionally, determining a concomitant wave field of the target imaging region based on the perturbed wave field and the observed wave field data further comprises:

acquiring first observed wave field data acquired by a receiver after each of a plurality of seismic sources emits a shot of seismic waves;

acquiring Gaussian distribution random numbers corresponding to each seismic source;

substituting the Gaussian distribution random number corresponding to each seismic source and the first observed wave field data into a formula

Obtaining the observed wavefield data, wherein d _super Omega for the observed wavefield data _i For the Gaussian distribution random number corresponding to the ith seismic source, d _i And (3) the first observed wave field data corresponding to the ith seismic source is obtained, and N is the number of the seismic sources.

Optionally, the determining, by the intermittent finite element method, a disturbance wave field of the target imaging region based on a background slowness of the irregular grid, a position coordinate of a center point of the irregular grid, the first slowness disturbance, the medium density, and the background wave field includes:

substituting the background slowness of the irregular grid, the position coordinates of the center points of the irregular grid, the first slowness disturbance, the medium density and the background wave field into a formula

Obtaining a perturbed wavefield of the target imaging region, wherein (p) _s ，u _s ，w _s ) For the perturbed wavefield, ρ is the medium density, Δs ² For the first slowness disturbance, p ₀ S is the background wave field ₀ For the background slowness of the irregular grid,the target background speed parameter of the irregular grid is t is time, and (x, z) is the position coordinate of the center point of the irregular grid;

the determining a concomitant wave field of the target imaging region based on the position coordinates of the irregular grid center points, the perturbed wave field, the medium density, the observed wave field data, comprising:

Substituting the position coordinates of the center points of the irregular grid, the disturbed wave field, the medium density and the observed wave field data into a formula

Obtaining the wavefield, wherein (p) ^* ，u ^* ，w ^* ) For the satellite wave field, (p) _obs ，u _obs ，w _obs ) For the observed wave fieldData.

Optionally, the determining a first gradient for updating the first slowness disturbance based on the satellite wavefield and the background wavefield comprises:

substituting the adjoint wave field and the background wave field into a formula

And obtaining the first gradient, wherein g is the first gradient, and T is the maximum recording duration.

Optionally, the performing offset imaging on the target imaging area based on the target slowness disturbance includes:

determining, by the discontinuous finite element method, a first wavefield based on a target background velocity parameter of the irregular grid, the target slowness disturbance, the medium density, the background wavefield and the observed wavefield data;

determining a second gradient for updating the target slowness disturbance based on the first satellite wave field and the background wave field;

correcting the second gradient based on the second gradient, the first gradient and a preset attenuation coefficient;

Updating the target slowness disturbance based on the preset gradient descent method and the corrected second gradient to obtain a second slowness disturbance;

and performing offset imaging on the target imaging area based on the second slowness disturbance.

In a second aspect, embodiments of the present invention provide a seismic migration apparatus based on an irregular grid, the apparatus comprising:

the parameter determining module is used for determining a target background speed parameter of each irregular grid in the target imaging area based on an interpolation method and the background speed parameter of the target imaging area;

a wavefield determination module for determining, by a discontinuous finite element method, an accompanying wavefield of the target imaging region based on a target background velocity parameter, a first slowness disturbance, a medium density, a background wavefield and observed wavefield data of the irregular grid;

a gradient determination module for determining a first gradient for updating the first slowness disturbance based on the satellite wavefield and the background wavefield;

the updating module is used for updating the first slowness disturbance based on a preset gradient descent method and the first gradient to obtain a target slowness disturbance;

And the imaging module is used for carrying out offset imaging on the target imaging area based on the target slowness disturbance.

Optionally, the parameter determining module is configured to:

Optionally, the wave field determining module is configured to:

Optionally, the apparatus further comprises:

the data acquisition module is used for acquiring first observation wave field data acquired by a receiver after each of a plurality of seismic sources emits a shot of seismic waves;

the data acquisition module is used for acquiring Gaussian distribution random numbers corresponding to each seismic source;

a determining module for substituting the Gaussian distribution random number corresponding to each seismic source and the first observed wave field data into a formula

Optionally, the wave field determining module is configured to:

Obtaining the wavefield, wherein (p) ^* ，u ^* ，w ^* ) For the satellite wave field, (p) _obs ，u _obs ，w _obs ) For the observed wavefield data.

Optionally, the gradient determining module is configured to:

Optionally, the imaging module is configured to:

In a third aspect, an embodiment of the present invention provides an electronic device, including a processor, a memory, and a computer program stored on the memory and executable on the processor, the computer program implementing the steps of the seismic migration method based on an irregular grid provided in the first aspect when executed by the processor.

In a fourth aspect, embodiments of the present invention provide a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the irregular grid-based seismic migration method provided in the first aspect above.

As can be seen from the technical solutions provided in the embodiments of the present invention, the embodiments of the present invention determine, based on an interpolation method and a background velocity parameter of a target imaging area, a target background velocity parameter of each irregular grid in the target imaging area, determine, by a discontinuous finite element method, an accompanying wave field of the target imaging area based on the target background velocity parameter, a first slowness disturbance, a medium density, a background wave field and observed wave field data of the irregular grid, determine, based on the accompanying wave field and the background wave field, a first gradient for updating the first slowness disturbance, update the first slowness disturbance based on a preset gradient descent method and the first gradient, obtain a target slowness disturbance, and perform offset imaging on the target imaging area based on the target slowness disturbance. In this way, the irregular mesh subdivision is carried out on the target imaging area, the undulating structure of the earth surface can be well approximated, the offset imaging is carried out on the target program area under the condition of the target slowness disturbance obtained by the intermittent finite element method, the influence of scattered waves caused by trapezoidal approximation can be reduced, and the imaging accuracy of the target imaging area with a complex structure is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a seismic migration method based on an irregular grid according to the present invention;

FIG. 2 is a schematic illustration of initial velocity data for a target imaging region;

FIG. 3 is a schematic representation of the result of an irregular triangulation of a target imaging region according to the present invention;

FIG. 4 is a flow chart of another seismic migration method based on an irregular grid according to the present invention;

FIG. 5 is a schematic illustration of the imaging result of a target imaging region according to the present invention;

FIG. 6 is a schematic diagram of an error curve comparison of the present invention;

FIG. 7 is a schematic diagram of a seismic migration apparatus based on an irregular grid according to the present invention;

fig. 8 is a schematic structural diagram of an electronic device according to the present invention.

Detailed Description

The embodiment of the invention provides a seismic migration method and device based on an irregular grid and electronic equipment.

In order to make the technical solution of the present invention better understood by those skilled in the art, the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, shall fall within the scope of the invention.

Example 1

As shown in fig. 1, the embodiment of the present disclosure provides a seismic migration method based on an irregular grid, where the implementation subject of the method may be a server, and the server may be an independent server or a server cluster formed by a plurality of servers. The method specifically comprises the following steps:

in S102, a target background velocity parameter for each irregular grid in the target imaging region is determined based on the interpolation and the background velocity parameters for the target imaging region.

The background speed parameter may be a field acquired area, the background speed parameter may be determined based on initial speed data of the target imaging area, for example, the initial speed data of the target imaging area may be obtained, filtering processing may be performed on the initial speed data through a preset filtering algorithm (such as a gaussian smoothing filtering algorithm) to obtain a background speed parameter of the target imaging area, a method for determining the background speed parameter may be various, the background speed parameter may be different according to different practical application scenarios (such as a ground geometry of the target imaging area), the irregular grid may be obtained by performing grid subdivision on the target imaging area based on a preset irregular grid subdivision algorithm, for example, a processing mechanism of a Delaunay triangulation algorithm may be preset in a server, and an irregular triangular grid subdivision may be performed on the target imaging area through the Delaunay triangulation algorithm.

In practice, seismic exploration methods are an important tool for human acquisition of subsurface space information, where seismic offset imaging is a key step in seismic data processing. The offset can accurately return the reflected wave, has the characteristics of high imaging precision and wide adaptability, and can intuitively display the real form of the underground structure.

At present, an imaging area with complex terrain structure and large surface fluctuation can be subjected to offset imaging by a least square reverse time offset method based on an inversion idea through regular grid subdivision. However, when an imaging region with a large relief of the processed surface is offset imaged, the trapezoidal approximation causes scattered waves to be generated, which may cause poor imaging accuracy of the imaging region. Therefore, the embodiment of the present invention provides a technical solution capable of solving the above problems, and specifically can be seen in the following:

a plurality of different seismic sources and receivers can be placed at different positions in the target imaging area, the seismic sources can be excited to emit seismic waves, and the receivers can acquire corresponding waveform record data to obtain the waveform record data corresponding to each seismic source.

The initial velocity data of the target imaging region (as shown in fig. 2) can be acquired for the actual exploration data of the target imaging region, the initial velocity data of the target imaging region is input into the server, and the server can process the initial velocity data based on a preset filtering algorithm to obtain the background velocity parameter of the target imaging region.

The server may determine a target background velocity parameter for each irregular grid based on the irregular grid subdivision results as shown in fig. 3, and the background velocity parameter for the target imaging area. As can be seen from fig. 3, the split irregular grid can better approximate the undulating configuration of the earth's surface.

The target background velocity parameter of each irregular grid may be determined based on the interpolation method and the background velocity parameter of the target program area corresponding to each irregular grid, for example, taking the irregular grid as an example of the irregular triangular grid as shown in fig. 3, and the target background velocity parameter of the irregular triangular grid may be determined based on the background velocity parameters of three vertices of the irregular triangular grid and the interpolation method.

The method for determining the target background speed parameter of the irregular grid may be various, and may be different according to different practical application scenarios, which is not particularly limited in the embodiment of the present disclosure.

In S104, a concomitant wavefield of the target imaging region is determined by a discontinuous finite element method based on the target background velocity parameter, the first slowness disturbance, the medium density, the background wavefield and the observed wavefield data of the irregular grid.

In practice, the server may forward model the irregular grid's target background velocity parameters, first slowness disturbance, medium density, background wavefield and observed wavefield data by a discontinuous finite element method to determine the concomitant wavefield of the target imaging region.

In S106, a first gradient for updating the first slowness disturbance is determined based on the satellite wave field and the background wave field.

In practice, the server may determine the first gradient for updating the first slowness disturbance by the satellite wavefield and the background wavefield corresponding to each time in the maximum recording duration.

In S108, the first slowness disturbance is updated based on the preset gradient descent method and the first gradient to obtain a target slowness disturbance.

In implementations, for example, the server may update the first slowness disturbance based on a preset search step size and the first gradient to obtain the target slowness disturbance.

In S110, offset imaging is performed on the target imaging region based on the target slowness disturbance.

In practice, the server may perform offset imaging of the target imaging region based on the obtained target slowness disturbance, which may improve imaging accuracy of the target imaging region having a complex configuration (particularly, severe surface fluctuations), and improve imaging definition of near-surface structures and mid-depth structures.

The embodiment of the invention provides a seismic migration method based on irregular grids, which is characterized in that the method is based on an interpolation method and background speed parameters of a target imaging area, the target background speed parameters of each irregular grid in the target imaging area are determined, the accompanying wave field of the target imaging area is determined based on the target background speed parameters, first slowness disturbance, medium density, background wave field and observed wave field data of the irregular grid by a discontinuous finite element method, a first gradient for updating the first slowness disturbance is determined based on the accompanying wave field and the background wave field, the first slowness disturbance is updated based on a preset gradient descent method and the first gradient, the target slowness disturbance is obtained, and migration imaging is performed on the target imaging area based on the target slowness disturbance. In this way, the irregular mesh subdivision is carried out on the target imaging area, the undulating structure of the earth surface can be well approximated, the offset imaging is carried out on the target program area under the condition of the target slowness disturbance obtained by the intermittent finite element method, the influence of scattered waves caused by trapezoidal approximation can be reduced, and the imaging accuracy of the target imaging area with a complex structure is improved.

Example two

As shown in fig. 4, an embodiment of the present invention provides a seismic migration method based on an irregular grid, where an execution body of the method may be a server, and the server may be an independent server or a server cluster formed by a plurality of servers. The method specifically comprises the following steps:

in S402, four related points corresponding to the center point of the irregular grid are selected based on a preset related point selection rule.

In practice, the user may obtain location information of a plurality of sources and receivers for the target imaging area, the user may input the location information of the plurality of sources and receivers into the server, i.e., the server may obtain location information of a plurality of sources and receivers for the target imaging area, e.g., based on actual survey data, the user may input location information of N sources and M receivers (e.g., location coordinates) for the target imaging area into the server.

After the server obtains the result of the irregular grid subdivision of the target imaging area, the position information of each of the N seismic sources input by the user may be matched with the result of the irregular grid subdivision of the target imaging area to determine the corresponding position of the position information of each seismic source in the irregular grid of the target imaging area (i.e., determine the corresponding position of the seismic source in the irregular grid), and similarly, the server may also match the position information of each of the M receivers with the result of the irregular grid subdivision of the target imaging area to determine the corresponding position of each receiver in the irregular grid of the target imaging area. Wherein, the corresponding position of the seismic source (or receiver) in the irregular grid may include a grid number in the irregular grid corresponding to the position information of the seismic source (or receiver), corresponding grid coordinates, and the like.

After matching, four correlation points corresponding to the center point of each irregular grid in the location information of the source or receiver may be obtained.

In S404, the position coordinates of each relevant point in the depth and horizontal directions and the background speed parameter are acquired.

In practice, the irregular grid may be matched with the location information of the seismic source to obtain the location coordinates of the center point of the irregular grid and the four related points in the depth and horizontal directions, as well as the background velocity parameters. The obtained position coordinates may be actual exploration position information of the seismic source and the receiver when seismic wave acquisition is performed on the target imaging area, and the position information may be known data obtained through exploration data.

In S406, the position coordinates of each of the four related points in the depth and horizontal directions and the background speed parameters are substituted into the formula

And obtaining the background speed parameter of the central point of the irregular grid.

Wherein,c is a background speed parameter of the center point of the irregular grid _i,j 、c _i+1,j 、c _i,j+1 And c _i+1,j+1 Background velocity parameters for four related points, respectively, (x) _i ，z _j )、(x _i+1 ，z _j )、(x _i ，z _j+1 ) And (x) _i+1 ，z _j+1 ) The position coordinates of the four relevant points, respectively.

In S408, the background speed parameter of the center point of the irregular grid is determined as the target background speed parameter of the irregular grid.

In S410, first observed wavefield data acquired by a post-shot seismic wave receiver of each of a plurality of sources is acquired.

In S412, a gaussian distribution random number corresponding to each source is acquired.

In S414, the Gaussian distribution random number and the first observed wavefield data corresponding to each source are substituted into the formula

Observed wavefield data is obtained.

Wherein d _super To observe wave field data, ω _i For the Gaussian distribution random number corresponding to the ith seismic source, d _i And the first observed wave field data corresponding to the ith seismic source is obtained, and N is the number of the seismic sources.

In S416, a background slowness of the irregular grid is determined based on the target background velocity parameters of the irregular grid.

In implementations, the background slowness of the irregular grid may be the inverse of the target background velocity parameter.

In S418, the position coordinates of the center point of each irregular grid in the depth and horizontal directions are acquired.

In S420, a perturbed wavefield of the target imaging region is determined by a discontinuous finite element method based on the background slowness of the irregular grid, the position coordinates of the center points of the irregular grid, the first slowness perturbation, the medium density, the background wavefield.

In practice, the background slowness of the irregular grid, the position coordinates of the center points of the irregular grid, the first slowness disturbance, the medium density, the background wavefield may be substituted into the formula

Obtaining a disturbance wave field of the target imaging area. Wherein, (p) _s ，u _s ，w _s ) For a disturbed wave field, ρ is the medium density, Δs ² For the first slowness disturbance, p ₀ S is the background wave field ₀ As a background slowness of the irregular grid,the target background speed parameter of the irregular grid is t is time, and (x, z) is the position coordinate of the center point of the irregular grid.

In S422, a concomitant wavefield of the target imaging region is determined based on the position coordinates of the irregular grid center points, the perturbed wavefield, the medium density, the observed wavefield data.

In practice, the residual of the observed wavefield data and the disturbed wavefield may be propagated in reverse time as the source term to obtain the accompanied wavefield, e.g., the position coordinates of the center points of the irregular grid, the disturbed wavefield, the medium density, and the observed wavefield data may be substituted into the formula

Obtaining a concomitant wavefield, wherein (p) ^* ，u ^* ，w ^* ) Is a satellite wave field, (p) _obs ，u _obs ，w _obs ) To observe wave field data d _super Three physical quantities are included.

In S424, a first gradient for updating the first slowness disturbance is determined based on the satellite wave field and the background wave field.

In practice, the satellite wave field and the background wave field may be substituted into the formula

A first gradient is obtained, wherein g is the first gradient and T is the maximum recording duration.

In S426, the first slowness disturbance is updated based on the preset gradient descent method and the first gradient to obtain a target slowness disturbance.

In S428, a first wavefield is determined by the intermittent finite element method based on the irregular grid' S target background velocity parameter, target slowness disturbance, medium density, background wavefield and observed wavefield data.

In S430, a second gradient for updating the target slowness disturbance is determined based on the first satellite wave field and the background wave field.

In S432, the second gradient is corrected based on the second gradient, the first gradient, and the preset attenuation coefficient.

In practice, since the first observed wavefield data for each source is aliased based on the gaussian distributed random numbers in S414 to obtain observed wavefield data, the second gradient may be modified to reduce the effect of randomness due to the gaussian distributed random numbers to improve imaging accuracy.

The second gradient, the first gradient and the preset attenuation coefficient can be substituted into the formula

A modified second gradient is obtained, wherein,g for the modified second gradient _k For the second gradient->For the first gradient, λ is a preset attenuation coefficient (may be a constant less than 1, such as 0.7, etc.).

In S434, the target slowness disturbance is updated based on the preset gradient descent method and the corrected second gradient to obtain a second slowness disturbance.

In S436, the target imaging region is offset imaged based on the second slowness disturbance.

In implementation, before the offset imaging is performed on the target imaging area based on the second slowness disturbance, it may be determined whether the second slowness disturbance meets a preset update requirement, for example, whether a variation amplitude of the second slowness disturbance (i.e., a ratio between a difference value between the second slowness disturbance and the target slowness disturbance and the second slowness disturbance) is smaller than a preset threshold, and if the variation amplitude of the second slowness disturbance is smaller than the preset threshold, offset imaging may be performed on the target imaging area based on the second slowness disturbance.

If the second slowness does not meet the preset update requirement (e.g., the variation amplitude of the second slowness disturbance is not less than the preset threshold), the second slowness disturbance may be determined as the target slowness disturbance, and S428-S436 are executed again to obtain the second slowness disturbance again, and a determination is made as to whether the variation amplitude of the second slowness disturbance meets the preset update requirement.

Further, before performing S428 to S436, S414 may be performed again to determine observed wavefield data based on the regenerated gaussian distribution random numbers, and then S428 to S436 are performed.

In addition, in S426, the first slowness disturbance may be updated based on a preset search step, where the preset search step may be determined based on the disturbance wave field and the observed wave field data in S420, for example, the disturbance wave field may be calculated based on different search steps, and a search step corresponding to the disturbance wave field with the smallest difference between the disturbance wave field and the observed wave field data may be determined as the preset search step.

After the imaging of the target imaging area shown in fig. 2 is performed based on the steps, the imaging result shown in fig. 5 can be obtained, and the imaging result of fig. 5 shows that each reflection interface can be imaged clearly, the velocity discontinuities near the surface are accurate, the continuity is good, the image resolution is high, and the imaging amplitude is balanced.

In addition, fig. 6 is a graph showing a least-squares reverse time shift error drop curve (i.e., curve 2) obtained by imaging based on the corrected second gradient, compared with a least-squares reverse time shift error drop curve (i.e., curve 1) obtained by imaging based on the original gradient (i.e., the preset gradient), and it can be seen that the error drop of imaging based on the corrected second gradient is faster.

In summary, the embodiment of the present disclosure may perform least square inverse time shift on a complex structural region by using an irregular mesh subdivision and an intermittent finite element method, so as to improve imaging accuracy for a region having a complex structure (particularly, a region having severe surface fluctuation), and improve imaging definition of a near-surface structure and a mid-deep structure. Meanwhile, the first observation data of the seismic source are aliased through Gaussian distribution random numbers, and the first gradient calculated before is used for correcting the current second gradient, so that the calculation efficiency can be improved.

Example III

The seismic migration method based on the irregular grid provided in the embodiment of the present disclosure is based on the same concept, and the embodiment of the present disclosure further provides a seismic migration device based on the irregular grid, as shown in fig. 7.

The seismic migration apparatus based on an irregular grid includes: a parameter determination module 701, a wavefield determination module 702, a gradient determination module 703, an update module 704, and an imaging module 705, wherein:

a parameter determining module 701, configured to determine a target background velocity parameter of each irregular grid in a target imaging area based on interpolation and the background velocity parameter of the target imaging area;

a wavefield determination module 702 for determining, by a discontinuous finite element method, a concomitant wavefield of the target imaging region based on a target background velocity parameter, a first slowness disturbance, a medium density, a background wavefield and observed wavefield data of the irregular grid;

a gradient determination module 703 for determining a first gradient for updating the first slowness disturbance based on the satellite wave field and the background wave field;

an updating module 704, configured to update the first slowness disturbance based on a preset gradient descent method and the first gradient to obtain a target slowness disturbance;

And the imaging module 705 is used for performing offset imaging on the target imaging area based on the target slowness disturbance.

In the embodiment of the present invention, the parameter determining module 701 is configured to:

In an embodiment of the present invention, the wavefield determination module 702 is configured to:

In an embodiment of the present invention, the apparatus further includes:

Obtaining the observed wave fieldData, where d _super Omega for the observed wavefield data _i For the Gaussian distribution random number corresponding to the ith seismic source, d _i And (3) the first observed wave field data corresponding to the ith seismic source is obtained, and N is the number of the seismic sources.

/>

In an embodiment of the present invention, the gradient determination module 703 is configured to:

In an embodiment of the present invention, the imaging module 705 is configured to:

Example IV

Figure 8 is a schematic diagram of a hardware architecture of an electronic device implementing various embodiments of the invention,

the electronic device 800 includes, but is not limited to: radio frequency unit 801, network module 802, audio output unit 803, input unit 804, sensor 805, display unit 806, user input unit 807, interface unit 808, memory 809, processor 810, and power supply 811. It will be appreciated by those skilled in the art that the electronic device structure shown in fig. 8 is not limiting of the electronic device and that the electronic device may include more or fewer components than shown, or may combine certain components, or a different arrangement of components. In the embodiment of the invention, the electronic equipment comprises, but is not limited to, a mobile phone, a tablet computer, a notebook computer, a palm computer, a vehicle-mounted terminal, a wearable device, a pedometer and the like.

Wherein the processor 810 is configured to determine a target background velocity parameter for each irregular grid in the target imaging area based on interpolation and the background velocity parameter of the target imaging area;

the processor 810 is further configured to determine, by a discontinuous finite element method, a concomitant wavefield of the target imaging region based on a target background velocity parameter, a first slowness disturbance, a medium density, a background wavefield and observed wavefield data of the irregular grid;

The processor 810 is further configured to determine a first gradient for updating the first slowness disturbance based on the satellite wavefield and the background wavefield;

the processor 810 is further configured to update the first slowness disturbance based on a preset gradient descent method and the first gradient to obtain a target slowness disturbance;

the processor 810 is further configured to offset image the target imaging region based on the target slowness disturbance.

In addition, the processor 810 is further configured to select four relevant points corresponding to the center point of the irregular grid based on a preset relevant point selection rule;

in addition, the processor 810 is further configured to obtain a position coordinate of each of the relevant points in a depth direction and a horizontal direction, and a background velocity parameter;

in addition, the processor 810 is further configured to substitute the position coordinates of each of the four related points in the depth and horizontal directions and the background velocity parameter into a formula

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in addition, the processor 810 is further configured to determine a background velocity parameter of a center point of the irregular grid as a target background velocity parameter of the irregular grid.

In addition, the processor 810 is further configured to determine a background slowness of the irregular grid based on a target background velocity parameter of the irregular grid;

in addition, the processor 810 is further configured to obtain a position coordinate of a center point of each of the irregular grids in a depth direction and a horizontal direction;

further, the processor 810 is further configured to determine, by the discontinuous finite element method, a disturbance wavefield of the target imaging region based on a background slowness of the irregular grid, a position coordinate of a center point of the irregular grid, the first slowness disturbance, the medium density, the background wavefield;

additionally, the processor 810 is further configured to determine a concomitant wavefield of the target imaging region based on the position coordinates of the irregular grid center points, the perturbed wavefield, the medium density, the observed wavefield data.

In addition, the processor 810 is further configured to obtain first observed wavefield data acquired by a receiver after each of the plurality of seismic sources emits a shot of seismic waves;

In addition, the processor 810 is further configured to obtain a gaussian distribution random number corresponding to each of the seismic sources;

in addition, the processor 810 is further configured to substitute the gaussian distribution random number corresponding to each of the seismic sources and the first observed wavefield data into a formula

In addition, the processor 810 is further configured to substitute the background slowness of the irregular grid, the position coordinates of the center points of the irregular grid, the first slowness disturbance, the medium density, the background wavefield into a formula

Obtaining the target imaging regionWherein, (p) _s ，u _s ，w _s ) For the perturbed wavefield, ρ is the medium density, Δs ² For the first slowness disturbance, p ₀ S is the background wave field ₀ For the background slowness of the irregular grid,the target background speed parameter of the irregular grid is t is time, and (x, z) is the position coordinate of the center point of the irregular grid;

in addition, the processor 810 is further configured to substitute the position coordinates of the irregular grid center points, the perturbed wavefield, the medium density, and the observed wavefield data into a formula

Furthermore, the processor 810 is further configured to substitute the satellite wave field and the background wave field into a formula

Additionally, the processor 810 is further configured to determine, by the intermittent finite element method, a first wavefield based on the target background velocity parameter, the target slowness disturbance, the media density, the background wavefield and the observed wavefield data of the irregular grid;

furthermore, the processor 810 is further configured to determine a second gradient for updating the target slowness disturbance based on the first satellite wave field and the background wave field;

in addition, the processor 810 is further configured to correct the second gradient based on the second gradient, the first gradient, and a preset attenuation coefficient;

in addition, the processor 810 is further configured to update the target slowness disturbance based on the preset gradient descent method and the modified second gradient to obtain a second slowness disturbance;

Additionally, the processor 810 is further configured to offset image the target imaging region based on the second slowness disturbance.

The embodiment of the invention provides electronic equipment, which is characterized in that the background speed parameter of each irregular grid in a target imaging area is determined based on an interpolation method and the background speed parameter of the target imaging area, the accompanying wave field of the target imaging area is determined based on the target background speed parameter, first slowness disturbance, medium density, background wave field and observed wave field data of the irregular grid through a discontinuous finite element method, a first gradient for updating the first slowness disturbance is determined based on the accompanying wave field and the background wave field, the first slowness disturbance is updated based on a preset gradient descent method and the first gradient, the target slowness disturbance is obtained, and offset imaging is performed on the target imaging area based on the target slowness disturbance. In this way, the irregular mesh subdivision is carried out on the target imaging area, the undulating structure of the earth surface can be well approximated, the offset imaging is carried out on the target program area under the condition of the target slowness disturbance obtained by the intermittent finite element method, the influence of scattered waves caused by trapezoidal approximation can be reduced, and the imaging accuracy of the target imaging area with a complex structure is improved.

It should be understood that, in the embodiment of the present invention, the radio frequency unit 801 may be used for receiving and transmitting signals during the process of receiving and transmitting information or communication, specifically, receiving downlink data from a base station, and then processing the received downlink data by the processor 810; and, the uplink data is transmitted to the base station. In general, the radio frequency unit 801 includes, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, and the like. In addition, the radio frequency unit 801 may also communicate with networks and other devices through a wireless communication system.

The electronic device provides wireless broadband internet access to the user through the network module 802, such as helping the user to send and receive e-mail, browse web pages, access streaming media, and the like.

The audio output unit 803 may convert audio data received by the radio frequency unit 801 or the network module 802 or stored in the memory 809 into an audio signal and output as sound. Also, the audio output unit 803 may also provide audio output (e.g., a call signal reception sound, a message reception sound, etc.) related to a specific function performed by the electronic device 800. The audio output unit 803 includes a speaker, a buzzer, a receiver, and the like.

The input unit 804 is used for receiving an audio or video signal. The input unit 804 may include a graphics processor (Graphics Processing Unit, GPU) 8041 and a microphone 8042, the graphics processor 8041 processing image data of still pictures or video obtained by an image capturing apparatus (such as a camera) in a video capturing mode or an image capturing mode. The processed image frames may be displayed on the display unit 806. The image frames processed by the graphics processor 8041 may be stored in the memory 809 (or other storage medium) or transmitted via the radio frequency unit 801 or the network module 802. The microphone 8042 can receive sound, and can process such sound into audio data. The processed audio data may be converted into a format output that can be transmitted to the mobile communication base station via the radio frequency unit 801 in case of a telephone call mode.

The electronic device 800 also includes at least one sensor 805 such as a light sensor, a motion sensor, and other sensors. Specifically, the light sensor includes an ambient light sensor and a proximity sensor, wherein the ambient light sensor can adjust the brightness of the display panel 8061 according to the brightness of ambient light, and the proximity sensor can turn off the display panel 8061 and/or the backlight when the electronic device 800 moves to the ear. As one of the motion sensors, the accelerometer sensor can detect the acceleration in all directions (generally three axes), and can detect the gravity and direction when stationary, and can be used for recognizing the gesture of the electronic equipment (such as horizontal and vertical screen switching, related games, magnetometer gesture calibration), vibration recognition related functions (such as pedometer and knocking), and the like; the sensor 805 may also include a fingerprint sensor, a pressure sensor, an iris sensor, a molecular sensor, a gyroscope, a barometer, a hygrometer, a thermometer, an infrared sensor, etc., which are not described herein.

The display unit 806 is used to display information input by a user or information provided to the user. The display unit 806 may include a display panel 8061, and the display panel 8061 may be configured in the form of a liquid crystal display (Liquid Crystal Display, LCD), an Organic Light-Emitting Diode (OLED), or the like.

The user input unit 807 is operable to receive input numeric or character information and to generate key signal inputs related to user settings and function controls of the electronic device. In particular, the user input unit 807 includes a touch panel 8071 and other input devices 8072. Touch panel 8071, also referred to as a touch screen, may collect touch operations thereon or thereabout by a user (e.g., operations of the user on touch panel 8071 or thereabout using any suitable object or accessory such as a finger, stylus, etc.). The touch panel 8071 may include two parts, a touch detection device and a touch controller. The touch detection device detects the touch azimuth of a user, detects a signal brought by touch operation and transmits the signal to the touch controller; the touch controller receives touch information from the touch detection device, converts it into touch point coordinates, sends the touch point coordinates to the processor 810, and receives and executes commands sent from the processor 810. In addition, the touch panel 8071 may be implemented in various types such as resistive, capacitive, infrared, and surface acoustic wave. In addition to the touch panel 8071, the user input unit 807 can include other input devices 8072. In particular, other input devices 8072 may include, but are not limited to, physical keyboards, function keys (e.g., volume control keys, switch keys, etc.), trackballs, mice, joysticks, and so forth, which are not described in detail herein.

Further, the touch panel 8071 may be overlaid on the display panel 8061, and when the touch panel 8071 detects a touch operation thereon or thereabout, the touch operation is transmitted to the processor 810 to determine a type of touch event, and then the processor 810 provides a corresponding visual output on the display panel 8061 according to the type of touch event. Although in fig. 8, the touch panel 8071 and the display panel 8061 are two independent components for implementing the input and output functions of the electronic device, in some embodiments, the touch panel 8071 and the display panel 8061 may be integrated to implement the input and output functions of the electronic device, which is not limited herein.

The interface unit 808 is an interface to which an external device is connected to the electronic apparatus 800. For example, the external devices may include a wired or wireless headset port, an external power (or battery charger) port, a wired or wireless data port, a memory card port, a port for connecting a device having an identification module, an audio input/output (I/O) port, a video I/O port, an earphone port, and the like. The interface unit 808 may be used to receive input (e.g., data information, power, etc.) from an external device and transmit the received input to one or more elements within the electronic apparatus 800 or may be used to transmit data between the electronic apparatus 800 and an external device.

The memory 809 can be used to store software programs as well as various data. The memory 809 may mainly include a storage program area that may store an operating system, application programs required for at least one function (such as a sound playing function, an image playing function, etc.), and a storage data area; the storage data area may store data (such as audio data, phonebook, etc.) created according to the use of the handset, etc. In addition, memory 409 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage device.

The processor 810 is a control center of the electronic device, connects various parts of the entire electronic device using various interfaces and lines, and performs various functions of the electronic device and processes data by running or executing software programs and/or modules stored in the memory 809, and invoking data stored in the memory 809, thereby performing overall monitoring of the electronic device. The processor 810 may include one or more processing units; preferably, the processor 810 may integrate an application processor that primarily handles operating systems, user interfaces, applications, etc., with a modem processor that primarily handles wireless communications. It will be appreciated that the modem processor described above may not be integrated into the processor 810.

The electronic device 800 may also include a power supply 811 (e.g., a battery) for powering the various components, and the power supply 811 may preferably be logically coupled to the processor 810 through a power management system that provides for managing charge, discharge, and power consumption.

Preferably, the embodiment of the present invention further provides an electronic device, including a processor 810, a memory 809, and a computer program stored in the memory 809 and capable of running on the processor 810, where the computer program when executed by the processor 810 implements each process of the embodiment of the seismic migration method based on the irregular grid, and the process can achieve the same technical effect, and for avoiding repetition, a detailed description is omitted herein.

Example five

The embodiment of the invention also provides a computer readable storage medium, on which a computer program is stored, which when executed by a processor, implements the processes of the embodiment of the seismic migration method based on the irregular grid, and can achieve the same technical effects, and in order to avoid repetition, the description is omitted here. Wherein the computer readable storage medium is selected from Read-Only Memory (ROM), random access Memory (Random Access Memory, RAM), magnetic disk or optical disk.

The embodiment of the invention provides a computer readable storage medium, which is used for determining a target background speed parameter of each irregular grid in a target imaging area based on an interpolation method and a background speed parameter of the target imaging area, determining an accompanying wave field of the target imaging area based on the target background speed parameter, first slowness disturbance, medium density, a background wave field and observed wave field data of the irregular grids through a discontinuous finite element method, determining a first gradient for updating the first slowness disturbance based on the accompanying wave field and the background wave field, updating the first slowness disturbance based on a preset gradient descent method and the first gradient to obtain the target slowness disturbance, and performing offset imaging on the target imaging area based on the target slowness disturbance. In this way, the irregular mesh subdivision is carried out on the target imaging area, the undulating structure of the earth surface can be well approximated, the offset imaging is carried out on the target program area under the condition of the target slowness disturbance obtained by the intermittent finite element method, the influence of scattered waves caused by trapezoidal approximation can be reduced, and the imaging accuracy of the target imaging area with a complex structure is improved.

It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may 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, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may 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, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of computer-readable media.

Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element.

The foregoing is merely exemplary of the present invention and is not intended to limit the present invention. Various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are to be included in the scope of the claims of the present invention.

Claims

1. An offset imaging method, comprising:

performing offset imaging on the target imaging region based on the target slowness disturbance;

wherein the determining the target background velocity parameter of each irregular grid in the target imaging region based on interpolation and the background velocity parameter of the target imaging region comprises:

Obtaining a background velocity parameter of a center point of the irregular grid, wherein，C, a background speed parameter for the central point of the irregular grid _i,j 、c _i+1,j 、c _i,j+1 And c _i+1,j+1 Background velocity parameters of the four related points, (x) _i ，z _j )、(x _i+1 ，z _j )、(x _i ，z _j+1 ) And (x) _i+1 ，z _j+1 ) The position coordinates of the four related points are respectively;

determining a background speed parameter of a central point of the irregular grid as a target background speed parameter of the irregular grid;

the determining, by a discontinuous finite element method, an associated wavefield of the target imaging region based on the target background velocity parameter, the first slowness disturbance, the medium density, the background wavefield and the observed wavefield data of the irregular grid, comprising:

Determining a concomitant wave field of the target imaging region based on the position coordinates of the irregular grid center points, the perturbed wave field, the medium density, the observed wave field data;

before said determining a concomitant wavefield of said target imaging region based on said perturbed wavefield and said observed wavefield data, further comprising:

Obtaining the observed wavefield data, wherein d _super Omega for the observed wavefield data _i For the Gaussian distribution random number corresponding to the ith seismic source, d _i The first observed wave field data corresponding to the ith seismic source is obtained, and N is the number of the seismic sources;

the determining, by the discontinuous finite element method, a disturbance wave field of the target imaging region based on a background slowness of the irregular grid, a position coordinate of a center point of the irregular grid, the first slowness disturbance, the medium density, and the background wave field, includes:

Obtaining a disturbance of the target imaging regionA dynamic field, wherein (p) _s ，u _s ，w _s ) For the perturbed wavefield, ρ is the medium density, Δs ² For the first slowness disturbance, p ₀ S is the background wave field ₀ For the background slowness of the irregular grid,the target background speed parameter of the irregular grid is t is time, and (x, z) is the position coordinate of the center point of the irregular grid;

2. The method of claim 1, wherein the determining a first gradient for updating the first slowness disturbance based on the satellite wavefield and the background wavefield comprises:

3. The method of claim 2, wherein the offset imaging the target imaging region based on the target slowness disturbance comprises:

4. An offset imaging apparatus, comprising:

the imaging module is used for performing offset imaging on the target imaging area based on the target slowness disturbance;

wherein, the parameter determining module is used for:

Obtaining a background velocity parameter of a center point of the irregular grid, wherein, C, a background speed parameter for the central point of the irregular grid _i,j 、c _i+1,j 、c _i,j+1 And c _i+1,j+1 Respectively isBackground velocity parameters of the four related points, (x) _i ，z _j )、(x _i+1 ，z _j )、(x _i ，z _j+1 ) And (x) _i+1 ，z _j+1 ) The position coordinates of the four related points are respectively;

the wave field determination module is used for:

the device further comprises:

the wave field determination module is used for:

5. An electronic device comprising a processor, a memory and a computer program stored on the memory and executable on the processor, which when executed by the processor implements the steps of the offset imaging method of any one of claims 1 to 3.

6. A computer readable storage medium, characterized in that it has stored thereon a computer program which, when executed by a processor, implements the steps of the offset imaging method according to any of claims 1 to 3.