阅读说明：本技术 Ovt域数据转换成方位角度域成像道集的方法及系统 (Method and system for converting OVT domain data into azimuth angle domain imaging gather ) 是由 曹丹平 朱兆林 梁锴 于 2020-06-11 设计创作，主要内容包括：本发明公开了一种OVT域数据转换成方位角度域成像道集的方法及系统,所述方法,首先,计算Dix层速度,并利用Dix层速度设置初始的深度域空间的层速度,并采用优化目标函数的方式,确定优化后的深度域空间的层速度；根据优化后的深度域空间的层速度,计算最大反射角,确定反射角范围；对方位角范围和反射角范围的区域进行网格划分,获得方位角度域网格；根据优化后的深度域空间的层速度和OVT域成像道集数据中的叠前时间偏移均方根速度,计算每个方位角对应的反射角,得到方位角域成像道集。本发明采用求解目标函数的方式,实现了横向变速介质中的OVT域数据转换成方位角域成像道集以提高AVA/AVAZ反演精度。(The invention discloses a method and a system for converting OVT domain data into an azimuth angle domain imaging gather, wherein the method comprises the steps of firstly, calculating Dix layer speed, setting layer speed of an initial depth domain space by using the Dix layer speed, and determining the layer speed of the optimized depth domain space by adopting a mode of optimizing a target function; calculating a maximum reflection angle according to the optimized layer speed of the depth domain space, and determining a reflection angle range; carrying out grid division on the regions of the azimuth angle range and the reflection angle range to obtain an azimuth angle domain grid; and calculating a reflection angle corresponding to each azimuth angle according to the optimized layer speed of the depth domain space and the pre-stack time migration root-mean-square speed in the OVT domain imaging gather data to obtain an azimuth angle domain imaging gather. The invention adopts a mode of solving the objective function, realizes the conversion of OVT domain data in the transverse variable speed medium into an azimuth domain imaging gather so as to improve the AVA/AVAZ inversion accuracy.)

1. A method for converting OVT domain data into an azimuthal angular domain imaging gather, the method comprising the steps of:

converting OVT domain data into an OVT domain imaging gather by adopting a time domain offset imaging method;

calculating Dix layer velocity according to the pre-stack time migration root-mean-square velocity in the OVT domain imaging trace set and the one-way travel time of the imaging ray in the OVT domain imaging trace set;

setting the layer velocity of the initial depth domain space by using the Dix layer velocity, and adopting an optimization objective functionDetermining the layer velocity of the optimized depth domain space; wherein v is_DIX-INTIs the Dix layer velocity, v_INTIs the layer velocity of depth domain space, r'₀An imaging exit point in a depth domain space;

calculating the maximum reflection angle according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, and determining the range (0, theta)_max) (ii) a Wherein, theta_maxIs the maximum reflection angle;

angle of azimuthThe range is (0, 360 DEG) and the reflection angle theta range is (0, theta)_max) Is subjected to gridding division to obtainAn azimuth angle domain grid;

and calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer speed of the depth domain space and the pre-stack time migration root-mean-square speed in the OVT domain imaging gather data to obtain a binning result which is used as the azimuth angle domain imaging gather.

2. The method for converting OVT domain data into an azimuthal angle domain imaging gather according to claim 1, wherein calculating Dix layer velocities according to pre-stack time migration root mean square velocity in the OVT domain imaging gather and imaging ray single-pass travel in the OVT domain imaging gather comprises:

according to the pre-stack time deviation root mean square velocity in the OVT domain imaging trace set and the imaging ray single-pass travel time in the OVT domain imaging trace set, using a formulaCalculating the Dix layer velocity v_DIX-INT(t); wherein t represents time, v_RMS(t,r₀) Pre-stack time migration root mean square velocity, r, in OVT domain imaging trace concentration₀And imaging ray emergent points in the OVT domain imaging channel set are obtained.

3. The method for converting OVT domain data into azimuth angle domain imaging gathers according to claim 2, wherein said using Dix layer velocities to set initial depth domain spatial layer velocities and using an optimization objective functionDetermining the optimized layer velocity of the depth domain space, specifically comprising:

using the formula v_INTSet the initial layer velocity v in depth domain space (z, r)_INTWherein, in the step (A),r＝r₀z represents the value of the z-axis of the (x, y, z) space,r represents a position value of an (x, y) plane of the (x, y, z) space;

layer velocity v using depth domain space_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂；

Imaging ray travel time τ from depth domain space₂Using the formulaCalculating an imaged exit point r 'of depth domain space'₀；

Calculating an objective function from imaged exit points of a depth domain spaceThe objective function value of (1);

judging whether the objective function value is smaller than an objective function threshold value or not to obtain a judgment result;

if the judgment result shows no, the layer velocity of the depth domain space is updated by using a conjugate gradient method, and the step is returned to_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂”；

And if the judgment result shows that the layer speed of the depth domain space is the same as the layer speed of the optimized depth domain space, outputting the updated layer speed of the depth domain space as the layer speed of the optimized depth domain space.

4. The method according to claim 3, wherein the calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer velocity in the depth domain space and the pre-stack time migration root-mean-square velocity in the OVT domain imaging gather data to obtain a binning result as the azimuth angle domain imaging gather specifically comprises:

according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, a formula is utilizedCalculating a reflection angle corresponding to each azimuth angle to obtain an azimuth angle domain imaging gather; where θ is the reflection angle.

5. The method of converting OVT domain data into an azimuth domain imaging gather according to claim 1, wherein the calculating a reflection angle corresponding to each azimuth angle in the azimuth domain grid according to the optimized layer velocity of the depth domain space and the pre-stack time migration root-mean-square velocity in the OVT domain imaging gather data to obtain a binning result as the azimuth domain imaging gather, further comprises:

and carrying out weighted interpolation and homogenization treatment on the binning result according to the distance between the seismic channel and the binning center of the binning result.

6. A system for converting OVT domain data into an azimuthal angular domain imaging gather, the system comprising:

the time domain offset imaging conversion module is used for converting the OVT domain data into an OVT domain imaging gather by adopting a time domain offset imaging method;

the Dix layer velocity calculating module is used for calculating the Dix layer velocity according to the pre-stack time migration root-mean-square velocity in the OVT domain imaging trace set and the imaging ray one-way travel time in the OVT domain imaging trace set;

a layer velocity optimization module of depth domain space for setting the initial layer velocity of depth domain space by using Dix layer velocity and adopting an optimization objective functionDetermining the layer velocity of the optimized depth domain space; wherein v is_DIX-INTIs a Dix layer velocityDegree, v_INTIs the layer velocity of depth domain space, r'₀An imaging exit point in a depth domain space;

a maximum reflection angle calculation module for calculating the maximum reflection angle according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, and determining the range (0, theta)_max) Wherein, theta_maxIs the maximum reflection angle;

a mesh division module for azimuth angleThe range is (0, 360 DEG) and the reflection angle theta range is (0, theta)_max) Carrying out grid division on the area to obtain an azimuth angle domain grid;

and the binning module is used for calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer speed of the depth domain space and the pre-stack time migration root-mean-square speed in the OVT domain imaging gather data to obtain a binning result which is used as the azimuth angle domain imaging gather.

7. The system for converting OVT domain data into an azimuthal angular domain imaging gather according to claim 6, wherein the Dix layer velocity calculating module specifically comprises:

a Dix layer velocity calculation submodule for using a formula according to the pre-stack time migration root mean square velocity in the OVT domain imaging trace set and the imaging ray one-way travel time in the OVT domain imaging trace setCalculating the Dix layer velocity v_DIX-INT(t); wherein t represents time, v_RMS(t,r₀) Pre-stack time migration root mean square velocity, r, in OVT domain imaging trace concentration₀And imaging ray emergent points in the OVT domain imaging channel set are obtained.

8. The system for converting OVT domain data into an azimuthal angular domain imaging gather according to claim 7, wherein the layer velocity optimization module of the depth domain space specifically comprises:

an initialization submodule for utilizing the formula v_INTSet the initial layer velocity v in depth domain space (z, r)_INTWherein, in the step (A),r＝r₀，r₀an imaging ray emergence point in an OVT domain imaging trace set is represented by t, time is represented by t, z represents a value of a z-axis of an (x, y, z) space, and r represents a position value of an (x, y) plane of the (x, y, z) space;

an imaging ray travel time solving submodule of the depth domain space for utilizing the layer velocity v of the depth domain space_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂；

An imaging exit point calculation submodule in the depth domain space for calculating the travel time τ according to the imaging ray in the depth domain space₂Using the formulaCalculating an imaged exit point r 'of depth domain space'₀；

An objective function value calculation submodule for calculating an objective function from the imaged exit point of the depth domain spaceThe objective function value of (1);

the judgment submodule is used for judging whether the objective function value is smaller than an objective function threshold value to obtain a judgment result;

a layer velocity updating submodule of the depth domain space, which is used for updating the layer velocity of the depth domain space by using a conjugate gradient method if the judgment result shows that the layer velocity is not the same as the layer velocity v of the depth domain space, and returning to the step of using the layer velocity v of the depth domain space_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂”；

And the optimized layer speed output submodule of the depth domain space is used for outputting the updated layer speed of the depth domain space as the optimized layer speed of the depth domain space if the judgment result shows that the layer speed of the depth domain space is positive.

9. The system for converting OVT domain data into an azimuthal angular domain imaging gather according to claim 8, wherein said binning module comprises:

a binning submodule for using a formula according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging channel set dataCalculating a reflection angle corresponding to each azimuth angle to obtain an azimuth angle domain imaging gather; where θ is the reflection angle.

10. The system for converting OVT domain data into an azimuthal angular domain imaging gather according to claim 6, further comprising:

and the weighted interpolation and homogenization processing module is used for carrying out weighted interpolation and homogenization processing on the binning result according to the distance between the seismic channel and the binning center of the binning result.

Technical Field

The invention relates to the technical field of seismic data processing, in particular to a method and a system for converting OVT domain data into an azimuth angle domain imaging gather.

Background

In the exploration of petroleum geoobjects, artificial earthquake is the most widely applied method, seismic waves generated by artificially exciting a seismic source are transmitted in an earth medium, seismic wave reflection signals are received by detectors arranged according to different geometric forms, data volumes of different dimensions are obtained, and the data volumes are further subjected to imaging processing by a modern computer software system to obtain the structural form and characteristics of the underground medium, namely seismic images. Seismic exploration can be divided into two-dimensional exploration and three-dimensional exploration according to different dimensionalities of seismic images; three-dimensional exploration has become the most common method of exploration in the industry due to the increased processing power of modern computers and the need to actually explore objects. The three-dimensional exploration observation system comprises four-dimensional coordinates of a seismic source point and a demodulator probe which are configured on a two-dimensional plane of the earth surface, and a travel time direction, so that the finally received seismic data has five dimensions; the five-dimensional coordinates have different space representation forms, the seismic source point, the demodulator probe and the travel time coordinate space data are transformed to obtain data under a central point, an offset and a travel time coordinate, wherein the central point represents the central position of a connecting line of the shot point and the demodulator probe, the offset represents a vector pointing to the demodulator probe from the seismic source point, and the azimuth and the absolute offset can be used for representation in a polar coordinate system. The relationship between Amplitude and Offset (AVO) or between Amplitude and reflection angle (AVA) is an important technical means for lithology and hydrocarbon characteristic analysis, and the prior AVA analysis and inversion do not consider azimuth characteristics (i.e. vector characteristics of Offset), so there is a certain limitation. Wide azimuth acquisition data is widely applied nowadays, and an azimuth AVA analysis technology is considered to be a relatively realistic requirement, but the advance of azimuth AVA inversion requires a data volume which changes with azimuth and offset (absolute offset), so that the five-dimensional OVT (offset vector Tile) data volume technology has an important significance for azimuth AVO/AVA inversion.

The five-dimensional OVT domain processing technology has become a wide azimuth seismic exploration technology (Yinxingyao and the like, 2018; Zhanshifan and the like, 2015) widely applied at home and abroad, and has important significance for the development of a technology of 'two widths and one height' in China. The OVT concept began to emerge at the end of the last century in the study of the design of wide-azimuth seismic data acquisition and observation systems (Vermeer, 1998; Cary,1999), and subsequently the practical application of the digital scientist (Jenner et al, 2001; Williams & Jenner,2001,2002) discovered that azimuth gathers have important advantages in studying azimuthal anisotropy velocity analysis and seismic amplitude variation characteristics with angle of incidence, azimuth (AVA/AVAZ). The five-dimensional OVT domain prestack gather data used for AVA/AVAZ analysis can fully utilize the azimuth characteristic of seismic data, effectively improve the analysis capability of underground complex media, for example, the attribute analysis of the OVT domain gather or AVA/AVAZ inversion estimation of fracture density and azimuth information and the like play an important role in reservoir prediction and reservoir description. The analysis and inversion technology based on the OVT domain gather enables the seismic interpretation to really enter a five-dimensional space to analyze and identify reservoir and oil reservoir characteristics, and obviously, the accurate azimuth angle domain imaging gather generation method is the basis of OVT domain prestack AVA/AVAZ inversion.

There are two ways to generate an azimuth domain imaging gather from OVT domain data: the method has the advantages that firstly, a direct method is adopted, namely OVT domain seismic data directly output azimuth angle domain imaging gathers through a depth domain or time domain migration imaging method, parallel design is difficult due to difference of input space and output space, the method is high in precision but low in efficiency, and especially wide application is difficult to realize in wide azimuth high-density seismic data; and the other is indirect method, namely OVT domain seismic data generates an OVT domain imaging gather by a time domain migration imaging method, then the imaging gather is projected from an azimuth offset space to an azimuth angle (reflection angle) space based on uniform or layered medium hypothesis to generate a final azimuth angle domain imaging gather. The offset-reflection angle conversion of the indirect method is based on the theories of Ostrander (1984), Todd & Backus (1985), Walden (2006) and Resnick (1993), and mainly contains information in several aspects: the medium is a homogeneous or laterally homogeneous (laminar) medium; the travel time formula meets the hyperbolic time difference formula; seismic data for a certain reflection angle is not from single offset reflection data, but from a superposition of reflection data for a range of offsets with a certain bandwidth. Bale (2001) and Mukhopadhyay and Mallick (2011) are used for obtaining a relevant mapping method based on a non-hyperbolic moveout or ray method in order to more accurately represent the offset-reflection angle conversion relation of a transverse isotropic medium with a vertical symmetry axis. In practical application, medium and small offset gather AVA/AVAZ analysis is still the mainstream, so that the consideration of large offset non-hyperbolic moveout or transverse isotropic media with vertical symmetric pumping is not a key problem, and the consideration of the transverse variable speed media problem can be more helpful to improve the AVA/AVAZ inversion accuracy. How to convert OVT domain data in a transverse variable speed medium into an azimuth domain imaging gather to improve AVA/AVAZ inversion accuracy becomes a technical problem to be solved urgently.

Disclosure of Invention

The invention aims to provide a method and a system for converting OVT domain data into an azimuth angle domain imaging gather, which are used for converting OVT domain data in a transverse variable speed medium into the azimuth angle domain imaging gather so as to improve AVA/AVAZ inversion accuracy.

In order to achieve the purpose, the invention provides the following scheme:

a method of converting OVT domain data to azimuth angle domain imaging gathers, the method comprising the steps of:

converting OVT domain data into an OVT domain imaging gather by adopting a time domain offset imaging method;

calculating Dix layer velocity according to the pre-stack time migration root-mean-square velocity in the OVT domain imaging trace set and the one-way travel time of the imaging ray in the OVT domain imaging trace set;

setting the layer velocity of the initial depth domain space by using the Dix layer velocity, and adopting an optimization objective functionDetermining the layer velocity of the optimized depth domain space; wherein v is_DIX-INTIs the Dix layer velocity, v_INTIs the layer velocity of the depth domain space,r₀' is an imaged exit point in depth domain space;

calculating the maximum reflection angle according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, and determining the range (0, theta)_max) Wherein, theta_maxIs the maximum reflection angle;

angle of azimuthThe range is (0, 360 DEG) and the reflection angle theta range is (0, theta)_max) Carrying out grid division on the area to obtain an azimuth angle domain grid;

and calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer speed of the depth domain space and the pre-stack time migration root-mean-square speed in the OVT domain imaging gather data to obtain a binning result which is used as the azimuth angle domain imaging gather.

Optionally, the calculating the Dix layer velocity according to the pre-stack time migration root-mean-square velocity in the OVT domain imaging trace set and the one-way travel time of the imaging ray in the OVT domain imaging trace set specifically includes:

according to the pre-stack time deviation root mean square velocity in the OVT domain imaging trace set and the imaging ray single-pass travel time in the OVT domain imaging trace set, using a formulaCalculating the Dix layer velocity v_DIX-INT(t); wherein t represents time, v_RMS(t,r₀) Pre-stack time migration root mean square velocity, r, in OVT domain imaging trace concentration₀And imaging ray emergent points in the OVT domain imaging channel set are obtained.

Optionally, the initial layer velocity of the depth domain space is set by using the Dix layer velocity, and an optimization objective function is adoptedDetermining the optimized layer velocity of the depth domain space, specifically comprising:

using the formula v_INTSet the initial layer velocity v in depth domain space (z, r)_INTWherein, in the step (A),r＝r₀，r₀an imaging ray emergence point in an OVT domain imaging trace set is represented by t, time is represented by t, z represents a value of a z-axis of an (x, y, z) space, and r represents a position value of an (x, y) plane of the (x, y, z) space;

layer velocity v using depth domain space_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂；

Imaging ray travel time τ from depth domain space₂Using the formulaCalculating an imaged exit point r of a depth domain space₀'；

Calculating an objective function from imaged exit points of a depth domain spaceThe objective function value of (1);

judging whether the objective function value is smaller than an objective function threshold value or not to obtain a judgment result;

if the judgment result shows no, the layer velocity of the depth domain space is updated by using a conjugate gradient method, and the step is returned to_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂”；

And if the judgment result shows that the layer speed of the depth domain space is the same as the layer speed of the optimized depth domain space, outputting the updated layer speed of the depth domain space as the layer speed of the optimized depth domain space.

Optionally, the calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer velocity of the depth domain space and the pre-stack time migration root-mean-square velocity in the OVT domain imaging gather data to obtain a binning result, and the binning result is used as the azimuth angle domain imaging gather, and specifically includes:

according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, a formula is utilizedAnd calculating a reflection angle corresponding to each azimuth angle to obtain an azimuth angle domain imaging gather.

Optionally, the calculating, according to the optimized layer velocity in the depth domain space and the pre-stack time migration root-mean-square velocity in the OVT domain imaging gather data, a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid to obtain a binning result, which is used as the azimuth angle domain imaging gather, and then further includes:

and carrying out weighted interpolation and homogenization treatment on the binning result according to the distance between the seismic channel and the binning center of the binning result.

A system for converting OVT domain data into an azimuth angle domain imaging gather, the system:

the time domain offset imaging conversion module is used for converting the OVT domain data into an OVT domain imaging gather by adopting a time domain offset imaging method;

the Dix layer velocity calculating module is used for calculating the Dix layer velocity according to the pre-stack time migration root-mean-square velocity in the OVT domain imaging trace set and the imaging ray one-way travel time in the OVT domain imaging trace set;

a layer velocity optimization module of depth domain space for setting the initial layer velocity of depth domain space by using Dix layer velocity and adopting an optimization objective functionDetermining the layer velocity of the optimized depth domain space; wherein v is_DIX-INTIs the Dix layer velocity, v_INTIs the layer velocity of the depth domain space, r₀Being' in depth spaceImaging an emergent point;

a maximum reflection angle calculation module for calculating the maximum reflection angle according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, and determining the range (0, theta)_max) Wherein, theta_maxIs the maximum reflection angle;

a mesh division module for azimuth angleThe range is (0, 360 DEG) and the reflection angle theta range is (0, theta)_max) Carrying out grid division on the area to obtain an azimuth angle domain grid;

and the binning module is used for calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer speed of the depth domain space and the pre-stack time migration root-mean-square speed in the OVT domain imaging gather data to obtain a binning result which is used as the azimuth angle domain imaging gather.

Optionally, the Dix layer velocity calculating module specifically includes:

a Dix layer velocity calculation submodule for using a formula according to the pre-stack time migration root mean square velocity in the OVT domain imaging trace set and the imaging ray one-way travel time in the OVT domain imaging trace setCalculating the Dix layer velocity v_DIX-INT(t); wherein t represents time, v_RMS(t,r₀) Pre-stack time migration root mean square velocity, r, in OVT domain imaging trace concentration₀And imaging ray emergent points in the OVT domain imaging channel set are obtained.

Optionally, the layer velocity optimization module in the depth domain space specifically includes:

an initialization submodule for utilizing the formula v_INTSet the initial layer velocity v in depth domain space (z, r)_INTWherein, in the step (A),r＝r₀，r₀an imaging ray emergence point in an OVT domain imaging trace set is represented by t, time is represented by t, z represents a value of a z-axis of an (x, y, z) space, and r represents a position value of an (x, y) plane of the (x, y, z) space;

an imaging ray travel time solving submodule of the depth domain space for utilizing the layer velocity v of the depth domain space_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂；

An imaging exit point calculation submodule in the depth domain space for calculating the travel time τ according to the imaging ray in the depth domain space₂Using the formulaCalculating an imaged exit point r of a depth domain space₀'；

An objective function value calculation submodule for calculating an objective function from the imaged exit point of the depth domain spaceThe objective function value of (1);

the judgment submodule is used for judging whether the objective function value is smaller than an objective function threshold value to obtain a judgment result;

a layer velocity updating submodule of the depth domain space, which is used for updating the layer velocity of the depth domain space by using a conjugate gradient method if the judgment result shows that the layer velocity is not the same as the layer velocity v of the depth domain space, and returning to the step of using the layer velocity v of the depth domain space_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂”；

And the optimized layer speed output submodule of the depth domain space is used for outputting the updated layer speed of the depth domain space as the optimized layer speed of the depth domain space if the judgment result shows that the layer speed of the depth domain space is positive.

Optionally, the binning module specifically includes:

a binning submodule for using a formula according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging channel set dataAnd calculating a reflection angle corresponding to each azimuth angle to obtain an azimuth angle domain imaging gather.

Optionally, the system further includes:

and the weighted interpolation and homogenization processing module is used for carrying out weighted interpolation and homogenization processing on the binning result according to the distance between the seismic channel and the binning center of the binning result.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the invention discloses a method and a system for converting OVT domain data into an azimuth angle domain imaging gather, wherein the method comprises the following steps: converting OVT domain data into an OVT domain imaging gather by adopting a time domain offset imaging method; calculating Dix layer velocity according to the pre-stack time migration root-mean-square velocity in the OVT domain imaging trace set and the one-way travel time of the imaging ray in the OVT domain imaging trace set; setting an initial layer speed of a depth domain space by using the Dix layer speed, and determining the layer speed of the optimized depth domain space by adopting a mode of optimizing an objective function; calculating a maximum reflection angle according to the optimized layer speed of the depth domain space and the pre-stack time migration root-mean-square speed in the OVT domain imaging gather data; in a range of azimuth angles ofAnd a reflection angle range of (0, theta)_max) Carrying out grid division on the area to obtain an azimuth angle domain grid; and calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer speed of the depth domain space and the pre-stack time migration root-mean-square speed in the OVT domain imaging gather data to obtain a binning result which is used as the azimuth angle domain imaging gather. The invention adopts the solution of the targetAnd the function mode realizes that OVT domain data in the transverse variable speed medium is converted into an azimuth domain imaging gather so as to improve the AVA/AVAZ inversion accuracy.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic ray diagram of a layered medium provided by the present invention;

FIG. 2 is a schematic view of an imaging beam of a laterally variable transmission medium provided by the present invention;

FIG. 3 is a flow chart of a method for converting OVT domain data into azimuth angle domain imaging gathers according to the present invention;

FIG. 4 is a schematic illustration of azimuth and reflection angle bins for AVA/AVAZ inversion provided by the present invention;

FIG. 5 is a trace set distribution in azimuth and reflection angle bins for AVA/AVAZ inversion provided by the present invention;

FIG. 6 is a schematic diagram of the distribution of the imaging gathers in the azimuthal offset space provided by the present invention;

fig. 7 is a schematic diagram of imaging gather conversion according to an embodiment of the present invention, where fig. 7(a) is an OVT domain prestack time migration imaging gather, fig. 7(b) is a schematic diagram of an azimuth angle domain imaging gather obtained by converting a conversion relationship from a migration distance to a reflection angle in a layered medium, and fig. 7(c) is a schematic diagram of an azimuth angle domain imaging gather obtained by using a method according to the present invention;

fig. 8 is a cross-sectional view of a single azimuth-angle azimuth-domain imaging gather according to an embodiment of the present invention, wherein fig. 8(a) is a cross-sectional view of a reflection angle of 4.5 ° at an azimuth angle of 30 °, fig. 8(b) is a cross-sectional view of a reflection angle of 4.5 ° at an azimuth angle of 90 °, fig. 8(c) is a cross-sectional view of a reflection angle of 13.5 ° at an azimuth angle of 30 °, and fig. 8(d) is a cross-sectional view of a reflection angle of 13.5 ° at an azimuth angle of 90 °.

Detailed Description

The invention aims to provide a method and a system for converting OVT domain data into an azimuth angle domain imaging gather, which are used for converting OVT domain data in a transverse variable speed medium into the azimuth angle domain imaging gather so as to improve AVA/AVAZ inversion accuracy.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

The invention aims to realize the conversion from OVT domain prestack time migration imaging gathers to azimuth angle domain imaging gathers in transversely variable-speed media. Firstly, researching a complex relation between accurate layer speed and prestack time migration speed in a transverse variable speed medium, and introducing a reflection angle and migration distance nonlinear conversion formula; then, the conversion from the OVT domain prestack time migration imaging gather to the azimuth angle domain imaging gather is realized; finally, the accurate azimuth angle domain imaging gather generation method obtained by the invention can provide effective input data for prestack AVA/AVAZ inversion.

The research content of the invention comprises: 1. researching a nonlinear conversion relation between the offset distance and the reflection angle in the transverse variable-speed medium from the conversion relation between the offset distance and the reflection angle in the traditional layered medium; 2. determining an objective function of an inversion problem of the OVT domain pre-stack time migration imaging gather at a known root mean square velocity by using the nonlinear conversion relation; 3. solving initial layer velocity by using a Dix formula according to the input root mean square velocity, solving a nonlinear equation system to obtain final layer velocity, and mapping the OVT domain pre-stack time migration gather to an azimuth angle domain imaging gather; 4. the invention adopts a binning algorithm in the azimuth angle domain imaging gather mapping process.

1. Conversion of offset to reflection angle in layered media:

the conversion relation of the offset distance to the reflection angle is the basic step of the traditional AVA/AVAZ inversion algorithm, and a simple derivation mode can be started from a uniform medium or a laminated medium (as shown in figure 1), and a solving formula of the reflection angle is gradually established based on the geometric relation of the snell's law. The formula for representing the reflection angle by ray parameters is as follows:

wherein, theta is an incident angle or a reflection angle, t is a two-way travel time, r is a horizontal distance from a shot point to a demodulator probe azimuth in the three-dimensional observation system,as a parameter of the radiation, v_INTThe layer velocity is indicated.

The invention is applied at a known root mean square velocity v_RMSAs the normal moveout correction speed, τ is the two-way travel time of zero offset self-excited self-collected according to the following hyperbolic travel time equation:

then obtain

Equation (1) is the most common basic equation for the conversion from offset to reflection angle. According to the method, a relatively complex formula (3) of a hyperbolic travel time equation (2) is obtained by solving a ray equation set of non-hyperbolic time difference by considering large offset distance or a reflection angle corresponding to anisotropy; considering that most of the AVA/AVAZ applications in practical production still focus on analyzing the characteristics of amplitude variation with offset corresponding to small offset, the following focuses on the problem of offset-angle conversion in the transverse velocity variation medium.

2. Conversion of offset to reflection angle in laterally variable media:

the conversion of offset distance-reflection angle by an indirect method relates to the problem of time-depth conversion, and imaging rays are the key for establishing the time-depth conversion; the imaging rays are seismic rays normal to the earth's surface. As shown in fig. 2, the imaging ray expresses a correspondence between the prestack time-shifted imaging gather space (X, Y, T) and the original model space (X, Y, Z). In the layer crossIn a uniform medium, imaging rays are straight lines vertical to the earth surface, so that the time-depth conversion and offset-angle conversion relation established on the basis of the imaging rays is relatively simple; whereas in a laterally variable medium the imaging radiation is a curved radiation, as shown in fig. 2, with a layer velocity v_INTRoot mean square velocity v used for pre-stack time migration_RMSThere is a very complex non-linear relationship between them. The Dix formula is a commonly used formula for converting the root mean square velocity and the layer velocity, and the generalized Dix formula describes the conversion relationship between the layer velocity and the root mean square velocity of the prestack time migration as follows:

wherein v is_DIX-INTIs the layer velocity, r, calculated by the Dix equation_CRepresenting the imaging ray surface location (x)₀，y₀),Representing the amount of geometric diffusion. Equation (4) illustrates that the Dix layer velocity does not fully represent the true layer velocity in the laterally variable medium, and the relationship with the true layer velocity needs to take into account the effects of geometric diffusion. The generalized Dix formula is different from the general Dix in that the derivative of the self-excited self-receiving double-pass travel becomes a partial derivative, Li&The Fome expresses the boundary value problem of the nonlinear partial differential equation of the imaging ray according to equation (4), a geometric diffusion expression and an equation of an engineering function. The non-thread equation set is a Cauchy problem of an elliptic equation and is ill-conditioned, the invention directly starts from equation (4) and changes the problem into an optimization problem, and the cost function is as follows:

the observed imaging ray body is present in the regular coordinate space of the prestack time migration imaging gather, and the Dix layer velocity can be obtained by the known prestack time migration root mean square velocity, then the objective function is obtained by the unknown real layer velocityDegree v_INTThe predicted imaging ray is compared to the observed imaging ray, the closer together the estimated v_INTThe more accurate. That is, if predicted r_CFailing to satisfy equation (5), v estimated at the previous time_INTReasonable updating needs to be carried out through an optimization algorithm, then the error of the objective function equation (5) is further reduced, and finally, reasonable layer velocity v is obtained through multiple times of iterative solution_INTThe value is obtained.

As mentioned above, the amplitude-preserved prestack time offset has been corrected for normal moveout and dip moveout, and compared to depth offset, the lateral shift problem of the medium is not fully considered, but the hyperbolic travel time equation (2) approximation is sufficient when only the reflection angle conversion problem corresponding to small and medium offsets is considered. Observing the formula (3), in the process of solving the reflection angle, the root mean square velocity v_RMSThe offset r and the time of travel t are known, then v_INTAnd sin θ is a linear mapping relationship. Transform equation (3) to obtain

Substituting equation (6) into equation (5) yields:

the above formula represents the cost function of the optimization problem solved by the reflection angle under the fixed offset, and as can be known from the formula, the geometric diffusion of the wavefront can be approximately expressed as

The geometric diffusion expression of equation (8) still has some physical meaning formally: tsin θ v_RMSThe horizontal propagation distance, r, the offset distance, and the geometric diffusion amount are approximated by a comparison of the horizontal propagation distance and the offset distance, plus a correction for the longitudinal-lateral velocity ratio (layer velocity and root-mean-square velocity). The approximation further weakens the nonlinear characteristics of the original formula (5), and is beneficial to the optimization of the cost function expression of the formula (7)And (5) solving the problem. Since the reflection angle is related to the offset, v is calculated by equation (5)_INTThe difference is that: if equation (7) is used directly to calculate the reflection angle, it is first necessary to fix the offset, at v_INTCalculating the size of the reflection angle of each grid point in the corresponding space (z, r), and remapping the grid points to (tau, r) according to the imaging ray₀) Space and the layer velocity field needs to be generated according to the formula (6), so that the direct solving of the reflection angle solving equation expressed by the equation (7) is complex, and v can be solved through the formula (5) firstly_INT(z, r) and then obtaining each sample point (tau, r) from the imaging radiation₀) Desired layer velocity v_INT(τ，r₀) And then obtaining corresponding reflection angles according to different offset distances by using a formula (3).

As shown in fig. 3, the method for converting OVT domain data into azimuth angle domain imaging gathers provided by the present invention comprises the following steps:

step 301, converting OVT domain data into an OVT domain imaging gather by using a time domain offset imaging method;

and step 302, calculating Dix layer velocity according to the pre-stack time migration root mean square velocity in the OVT domain imaging trace set and the one-way travel time of the imaging ray in the OVT domain imaging trace set.

Step 302 specifically includes: according to the pre-stack time deviation root mean square velocity in the OVT domain imaging trace set and the imaging ray single-pass travel time in the OVT domain imaging trace set, using a formulaCalculating the Dix layer velocity v_DIX-INT(t); wherein t represents time, v_RMS(t,r₀) Pre-stack time migration root mean square velocity, r, in OVT domain imaging trace concentration₀And imaging ray emergent points in the OVT domain imaging channel set are obtained.

Step 303, setting the layer velocity of the initial depth domain space by using the Dix layer velocity, and adopting an optimization objective functionDetermining the layer velocity of the optimized depth domain space(ii) a Wherein v is_DIX-INTIs the Dix layer velocity, v_INTIs the layer velocity of the depth domain space, r₀' is the imaged exit point of the depth domain space.

In the process of solving the layer speed in the transverse variable speed medium, a Fast Marching Method (FMM) method is used for solving a function equation and a conjugate gradient method is used for solving an optimization problem.

Step 303 specifically includes: using the formula v_INTSet the initial layer velocity v in depth domain space (z, r)_INTWherein, in the step (A),r＝r₀，r₀an imaging ray emergence point in an OVT domain imaging trace set is represented by t, time is represented by t, z represents a value of a z-axis of an (x, y, z) space, and r represents a position value of an (x, y) plane of the (x, y, z) space; layer velocity v using depth domain space_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂(ii) a Imaging ray travel time τ from depth domain space₂Using the formulaCalculating an imaged exit point r of a depth domain space₀'; calculating an objective function from imaged exit points of a depth domain spaceThe objective function value of (1); judging whether the objective function value is smaller than an objective function threshold value or not to obtain a judgment result; if the judgment result shows no, the layer velocity of the depth domain space is updated by using a conjugate gradient method, and the step is returned to_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂"; and if the judgment result shows that the layer speed of the depth domain space is the same as the layer speed of the optimized depth domain space, outputting the updated layer speed of the depth domain space as the layer speed of the optimized depth domain space.

Step 304, calculating the maximum reflection angle according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, and determining the range (0, theta)_max) Wherein, theta_maxIs the maximum reflection angle.

In particular, according to the formulaAnd a target layer tau to be analyzed, knowing the maximum offset distance | r |, the root mean square velocity and the layer velocity of the prestack time migration gather, calculating the maximum reflection angle theta_max。

Step 305, aligning the azimuth angleThe range is (0, 360 DEG) and the reflection angle theta range is (0, theta)_max) And carrying out grid division on the area to obtain an azimuth angle domain grid.

According to the range (0, theta)_max) And gather azimuth rangeAzimuthal-angular-domain grid required for distribution-case binning AVA/AVATypically the azimuthal angle is 60 ° and the reflection angles are 10-20 ° apart, and if the maximum reflection angle is 60 ° and the separation is 20 °, then the 6 × 3 binning format is typically used.

And step 306, calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer velocity of the depth domain space and the pre-stack time migration root-mean-square velocity in the OVT domain imaging gather data to obtain a binning result, and using the binning result as the azimuth angle domain imaging gather.

Azimuth angle gather binning algorithm:

after the OVT domain prestack time migration imaging gather is subjected to some processing corrections such as denoising and the like, the OVT domain prestack time migration imaging gather has some better characteristics, the OVT domain prestack time migration imaging gather carries azimuth and offset information, the offset distribution in a single imaging point gather is uniform, the integral amplitude energy distribution is relatively balanced, and the azimuth and offset distribution information between the imaging point gathers are basically the same; however, the OVT domain imaging point gather data volume is large, and the signal-to-noise ratio is not high. The OVT domain imaging gather facing AVA/AVAZ inversion analysis needs further processing: the OVT domain imaging gather is converted into an azimuth angle domain imaging gather, the original amplitude distribution characteristic needs to be kept at the moment, the azimuth is reasonably divided and kept, the difference in the amplitude azimuth is reduced, the inverted information redundancy is reduced, the convergence is improved, and meanwhile, the range from a shallow layer to a deep layer reflection angle is reduced due to the same offset distance, so that the consistency of the depth direction reflection angle division is kept according to the target horizon; after the azimuth and the reflection angle are reasonably divided and sampled, the inner related original gather of each surface element needs to be subjected to superposition or weighted interpolation.

Taking a 6 × 3 binning manner (as shown in fig. 4) in an azimuth angle domain coordinate system as an example, gather distribution detection is performed on the azimuth and reflection angle of a certain target layer of a certain imaging point gather (as shown in fig. 5).

Step 106 specifically includes: according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, a formula is utilizedAnd calculating a reflection angle corresponding to each azimuth angle to obtain an azimuth angle domain imaging gather.

Step 106 is followed by: and carrying out weighted interpolation and homogenization treatment on the binning result according to the distance between the seismic channel and the binning center of the binning result.

In fig. 5, although the azimuth data is wide, the distribution of the gathers in the vertical and horizontal line bins is not uniform, and the range of the reflection angle needs to be further reduced or the gathers need to be extrapolated to ensure the uniformity of the distribution of the AVA/AVAZ input data. The amplitude value of the center point of the surface element needs to be obtained through superposition or interpolation in the surface element, the problem relates to the problem of scattered point interpolation, and an inverse distance interpolation algorithm is selected to be used.

The inverse distance interpolation algorithm is a method for carrying out weighted interpolation by utilizing the difference between the distances of known data scatter and interpolation points, the weight sparseness is inversely proportional to the distances, and the problem of weight solving is emphasized. The inverse distance interpolation function and the weight values are represented as follows:

wherein the content of the first and second substances,is space of azimuth angle domainThe amplitude value of the frequency band,and A_nRespectively the weight and amplitude values of the nth scatter,is the nth scatter pointDistance d of points_nThe reciprocal of (a); amplitude and sin according to the approximate AVA formula²Theta is linear, let rho be sin²Theta, in polar coordinatesFinding the distance d in space_nThe formula is as follows:

the metric distance of equation (10) can be written in the form of a square, i.e.

Here, ρ ∈ [0, 1 ] is used]Since the inverse distance interpolation of equation (9) is still linear interpolation, the relationship model of amplitude and coordinate established in the polar coordinate space satisfies the linear form, and if the AVAZ approximate relationship of azimuth angle and amplitude is further considered, equation (11) includesAndthis relationship between amplitude and orientation can also be reflected.

The invention also provides a system for converting OVT domain data into an azimuth angle domain imaging gather, which comprises the following steps:

and the time domain offset imaging conversion module is used for converting the OVT domain data into the OVT domain imaging gather by adopting a time domain offset imaging method.

And the Dix layer velocity calculating module is used for calculating the Dix layer velocity according to the pre-stack time migration root-mean-square velocity in the OVT domain imaging trace set and the one-way travel time of the imaging ray in the OVT domain imaging trace set.

The Dix layer velocity calculating module specifically comprises: a Dix layer velocity calculation submodule for using a formula according to the pre-stack time migration root mean square velocity in the OVT domain imaging trace set and the imaging ray one-way travel time in the OVT domain imaging trace setCalculating the Dix layer velocity v_DIX-INT(t); wherein t represents time, v_RMS(t,r₀) Pre-stack time migration root mean square velocity, r, in OVT domain imaging trace concentration₀And imaging ray emergent points in the OVT domain imaging channel set are obtained.

A layer velocity optimization module of depth domain space for setting the initial layer velocity of depth domain space by using Dix layer velocity and adopting an optimization objective functionDetermining a layer of the optimized depth domain spaceSpeed; wherein v is_DIX-INTIs the Dix layer velocity, v_INTIs the layer velocity of the depth domain space, r₀' is the imaged exit point of the depth domain space.

The layer velocity optimization module of the depth domain space specifically comprises: an initialization submodule for utilizing the formula v_INTSet the initial layer velocity v in depth domain space (z, r)_INTWherein, in the step (A),r＝r₀z represents a value of a z-axis of the (x, y, z) space, and r represents a position value of an (x, y) plane of the (x, y, z) space; an imaging ray travel time solving submodule of the depth domain space for utilizing the layer velocity v of the depth domain space_INTUsing equation of solving equation of equationDetermine the imaging ray travel time τ of the depth domain space₂(ii) a An imaging exit point calculation submodule in the depth domain space for calculating the travel time τ according to the imaging ray in the depth domain space₂Using the formulaCalculating an imaged exit point r of a depth domain space₀'; an objective function value calculation submodule for calculating an objective function from the imaged exit point of the depth domain spaceThe objective function value of (1); the judgment submodule is used for judging whether the objective function value is smaller than an objective function threshold value to obtain a judgment result; a layer velocity updating submodule of the depth domain space, which is used for updating the layer velocity of the depth domain space by using a conjugate gradient method if the judgment result shows that the layer velocity is not the same as the layer velocity v of the depth domain space, and returning to the step of using the layer velocity v of the depth domain space_INTUsing equation of solving equation of equationOf a depth domain spaceImaging ray travel time τ₂"; and the optimized layer speed output submodule of the depth domain space is used for outputting the updated layer speed of the depth domain space as the optimized layer speed of the depth domain space if the judgment result shows that the layer speed of the depth domain space is positive.

A maximum reflection angle calculation module for calculating the maximum reflection angle according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging gather data, and determining the range (0, theta)_max) Wherein, theta_maxIs the maximum reflection angle.

A mesh division module for azimuth angleThe range is (0, 360 DEG) and the reflection angle theta range is (0, theta)_max) And carrying out grid division on the area to obtain an azimuth angle domain grid.

And the binning module is used for calculating a reflection angle corresponding to each azimuth angle in the azimuth angle domain grid according to the optimized layer speed of the depth domain space and the pre-stack time migration root-mean-square speed in the OVT domain imaging gather data to obtain a binning result which is used as the azimuth angle domain imaging gather.

The binning module specifically includes: a binning submodule for using a formula according to the optimized layer velocity of the depth domain space and the pre-stack time migration root mean square velocity in the OVT domain imaging channel set dataAnd calculating a reflection angle corresponding to each azimuth angle to obtain an azimuth angle domain imaging gather.

The system further comprises: and the weighted interpolation and homogenization processing module is used for carrying out weighted interpolation and homogenization processing on the binning result according to the distance between the seismic channel and the binning center of the binning result.

In order to illustrate the technical effects of the present invention, the present invention provides the following specific examples.

50 square kilometers of target imaging bins within a certain probe area: the horizontal line Inline number range 1751 and 2447 have a sampling interval of 12.5m, the horizontal line Crossline number range 2701 and 3623 have a sampling interval of 6.25m, the number of sampling points in longitudinal time is 2501, and the sampling interval is 2 ms. The target data volume is huge, if the azimuth angle domain imaging gather generated by the direct method is used for AVA/AVAZ, the smaller exploration area also needs longer seismic data processing time, and the azimuth angle domain imaging gather generated by the indirect method is more practical. The invention adopts the method to generate seismic data of different azimuths and different reflection angles required by AVA/AVAZ.

As shown in fig. 6, in the distribution of the OVT imaging gather in the azimuth-offset domain, firstly, an azimuth binning scheme in fig. 3 is considered, that is, in bins formed by dividing 360 ° at 60 ° intervals, seismic traces are extremely unevenly distributed, and reasonable angle gather data needs to be obtained by using an inverse distance interpolation method and a bin averaging method during binning; as shown in the offset direction in fig. 6, the gathers are not uniformly distributed in the offset direction between different azimuths, so that the reflection angles are not uniformly distributed after the reflection angles are obtained between different azimuths. In view of this, firstly, the method for converting the reflection angle by using the offset distance proposed herein is used to convert the reflection angle for each depth slice of each azimuth of each imaging gather, and then interpolation (equivalent to weighted superposition) is performed by using the amplitude scatter data distributed in each bin to obtain the final azimuth angle domain imaging gather.

As shown in fig. 7, the ordinate is time (time), and the ordinate is trace (data distribution) corresponding to the azimuth angle and the reflection angle. Fig. 7a shows an original OVT domain prestack time migration imaging gather, which can be obtained by a conventional offset-angle conversion method, such as formula (3), an azimuth angle domain imaging gather (such as fig. 7b), where 6 azimuths, i.e., 30 °, 90 °, 150 °, 210 °, 270 °, and 330 °, are selected, the reflection angle range of each azimuth is 0-72 °, and the sampling interval is 6 °; the input OVT field imaging gather is only 320 tracks, the distribution is extremely uneven, certain azimuth angle points (such as figure 6) lack the imaging gather, and the phenomenon of missing tracks in the azimuth angle field needs to be compensated by a bin homogenization lane borrowing method; FIG. 7c is a graph of an imaged gather obtained by mapping the offset distance to the angular domain space using the method of the present invention, i.e., based on the nonlinear relationship between the true layer velocity and the root mean square velocity used for prestack offset, the overall performance of the method results is more balanced and clearer than that of the conventional method, especially the shallow layer is better processed, and the distribution of the angular gathers is more reasonable.

In the actual AVA/AVAZ inversion, because the target layer has a certain depth, only the shallow reflection angle can reach the range of 0-72 degrees under a large enough offset distance, and in order to achieve the inversion stability, a larger reflection angle sampling interval is generally adopted, so that the difference of the reflection amplitude along with the angle change is effectively reflected, and the inversion redundant information is reduced. In fig. 7b and 7c, the angular gather data of a single azimuth still has a discontinuous phenomenon due to the sparseness of the original input gather, and can better meet the requirement of the AVA/AVAZ input data under the condition of a larger reflection angle sampling interval, and only a few sparseness tracks exist at the reflection angle sampling interval (for example, 3 tracks exist in each azimuth in a 6 × 3 scheme). FIG. 8 shows a slice of an azimuth angle domain imaging gather along the azimuth angle vector points, i.e., a section of a single azimuth angle vector point, to illustrate the processing of the actual data three-dimensional work area five-dimensional OVT seismic imaging gather data by the method of the present invention, where four azimuth angle vectors are shown, the azimuth angle vector coordinates being (30 °,4.5 °), (90 °,4.5 °), (30 °,13.5 °), and (90 °,13.5 °); each section is a three-dimensional data volume with a transverse slice above and two longitudinal slices below. Comparing fig. 8a with fig. 8b or fig. 8c with fig. 8d, respectively, the difference of amplitude is obtained when the reflection angle is the same and the orientation is different; comparing fig. 8a and 8c or 8b and 8d respectively, the difference of amplitude is more obvious when the azimuth is the same and the reflection angle is different, and in conclusion, the data can be used for AVA/AVAZ inversion analysis, and the inversion is more stable compared with the traditional azimuth-separated AVA inversion.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The principle and the implementation manner of the present invention are explained by applying specific examples, the above description of the embodiments is only used to help understanding the method of the present invention and the core idea thereof, the described embodiments are only a part of the embodiments of the present invention, not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.