Azimuth gather extraction method and system based on geophone offset vector sheets

A technology of offset vector slices and extraction methods, which is applied in the field of seismic exploration, can solve problems such as high hardware requirements and difficult computers, and achieve the effects of reducing the range of variation, reducing computing memory, and improving computing efficiency

Active Publication Date: 2020-07-31
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the rapid development of current seismic data acquisition technology, pre-stack seismic data are usually calculated on the order of T (1000G), which requires high computer hardware conditions, and ordinary computers cannot bear it.

Method used

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  • Azimuth gather extraction method and system based on geophone offset vector sheets
  • Azimuth gather extraction method and system based on geophone offset vector sheets
  • Azimuth gather extraction method and system based on geophone offset vector sheets

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Embodiment 1

[0027] This embodiment provides a method for extracting azimuth gathers based on offset vector slices, including the following steps:

[0028] S1 divides the seismic data into several offset vector slices.

[0029] S2 calculates the ground azimuth of each offset vector sheet, the method for calculating the ground azimuth in this step is calculated according to the method of the offset vector sheet (OVT) gather, because this method is a method known in the art , so it will not be repeated here.

[0030] S3 performs three-dimensional Kirchhoff integral pre-stack time migration on the seismic data in each offset vector slice, and calculates the corresponding subsurface scattering azimuth and reflection angle.

[0031] S4 retains the underground scattering azimuth that is consistent with the ground azimuth angle. It should be noted that the consistency with the ground azimuth angle here does not mean that it must be completely consistent. For example, the ground azimuth angle is ...

Embodiment 2

[0046] In order to facilitate and better explain the solution in the first embodiment, this embodiment selects typical SEG-3D-anisotropy model data for testing to verify the accuracy of the method in the first embodiment.

[0047] image 3 It is a schematic diagram of the P-wave velocity of the SEG-3D-anisotropy model in an embodiment of the present invention, image 3 (a) is the vertical P-wave velocity of the model, image 3 (b) is the P-wave velocity in the direction of the anisotropy parameter e of the model, image 3 (c) is the P-wave velocity in the direction d of the anisotropy parameter of the model. Figure 4 It is a structural schematic diagram of the observation system of the SEG-3D-anisotropic model in an embodiment of the present invention; the observation system is 33 shot lines, each shot line has 101 shots, a total of 3333 shots (0000-3332), each shot 401 * 401 (160801) channels receive, the shot distance is 120m, the shot line distance is 360m, and the long...

Embodiment 3

[0049] Based on the same inventive concept, this embodiment discloses that the present invention also provides a system for extracting azimuth gathers based on offset vector slices, including:

[0050] The reflection angle distribution map module is used to select several x-axes in a plane according to the preserved subsurface scattering azimuth, the x-axis is used to represent the angle change of the emission angle, the normal direction of the plane is the z-axis, and the z-axis is used to represent the formation Depth change, the reflection angle is marked in the x-z coordinate system to obtain the reflection angle distribution map; the azimuth angle gather acquisition module is used to obtain the azimuth angle gather according to the reflection angle distribution map.

[0051] Among them, the formula for calculating the scattering azimuth angle is:

[0052]

[0053] Among them, P M is the sum of the incident slowness vector and the scattered slowness vector; P R is the...

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Abstract

The invention provides an azimuth gather extraction method and system based on geophone offset vector sheets. The method comprises the following steps: dividing seismic data into a plurality of geophone offset vector sheets; calculating a ground azimuth angle of each geophone offset vector sheet; performing three-dimensional Kirchhoff integral pre-stack time migration on the acquired seismic data,and calculating an underground scattering azimuth angle and a reflection angle; reserving an underground scattering azimuth angle consistent with the ground azimuth angle; selecting a plurality of xaxes in a plane according to the reserved underground scattering azimuth angles, wherien the x axes are used for representing angle changes of emission angles, the normal direction of the plane is a zaxis, the z axis is used for representing stratum depth changes, and the obtained reflection angles are marked in an x-z coordinate system to obtain a reflection angle distribution map; and obtainingan azimuth gather according to the reflection angle distribution map. The change range of the scattering field angle gamma and the scattering azimuth angle is effectively reduced, memory and hard disk resources can be greatly saved, and the calculation period is shortened.

Description

technical field [0001] The invention relates to a method and system for extracting azimuth gathers based on offset vector slices, and belongs to the technical field of seismic exploration. Background technique [0002] In 3D seismic exploration, azimuth gathers have extremely important application value. The existing azimuth gathers are usually extracted by the method of three-dimensional Kirchhoff integral pre-stack time migration. When extracting the migration azimuth gather, it is necessary to take a sample point in the imaging space according to its seven The feature parameters are placed in a seven-dimensional space. The seven dimensions are the three-dimensional coordinates X, Y, Z of the imaging point, the scattering angle γ, and the scattering azimuth Illumination inclination Θ and illumination azimuth ψ. Therefore, there are huge challenges both in terms of hard disk memory and computational cost. Due to the rapid development of current seismic data acquisition...

Claims

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Application Information

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IPC IPC(8): G01V1/30
CPCG01V1/302G01V1/307G01V2210/63
Inventor 刘春成杨锴陈宝书刘守伟薛冬叶云飞陶杰管西竹
Owner CHINA NAT OFFSHORE OIL CORP
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