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Mixing absorption boundary method based on transmission boundary

A technology for absorbing boundaries and boundaries, applied in the field of seismic exploration, can solve problems such as large computing memory and computing costs, and achieve the effects of improving accuracy, saving computing costs, and excellent absorption effects

Pending Publication Date: 2022-05-10
NORTHEAST GASOLINEEUM UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Liu and Sen (2018) proposed a weight function based on a single index, which can effectively reduce the inner boundary reflection, but there are still some outer boundary reflections
[0006] At present, most of the existing boundaries are for elastic media, and there is still no efficient and high-precision boundary processing method in viscous wave field simulation
And compared with elastic media, viscous wave field simulation requires larger computing memory and computing cost, especially in the three-dimensional case

Method used

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  • Mixing absorption boundary method based on transmission boundary
  • Mixing absorption boundary method based on transmission boundary
  • Mixing absorption boundary method based on transmission boundary

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0064] refer to Figure 1-Figure 5 , a hybrid absorption boundary method based on a transmission boundary, the hybrid absorption boundary method comprising the following steps:

[0065] Step 1. Set seismic source, receiver point and model size seismic record information;

[0066] Step 2, calculate the viscoacoustic wave field for the internal calculation area (area 1), the transition area (area 2) between the viscoacoustic wave field and the transmitted wave field, and obtain the two-way wave field value;

[0067] For the calculation of the two-way wave equation in the internal calculation area (physical domain) and the transition zone, the second-order constant-Q viscoacoustic equation is used to simulate the propagation of seismic waves in viscous media, which is expressed as:

[0068]

[0069] In the formula, p 1 and represent the two-way viscous wave field and the Laplacian operator, respectively, c 0 is defined at the reference frequency ω 0 The reference phase...

Embodiment 2

[0094] In order to verify the advantages of the self-adaptive weight function of this method, a model with a grid point size of 150×150×150 is tested, the intervals in the x, y, and z directions are all 10m, the absorption boundary is 30 layers, and the time step is 1ms. The background velocity of the model is 3000m / s, the quality factor Q is 50, the ricker wavelet with the main frequency of 30Hz is used as the source function, and the shot point is located in the center of the model. Figure 6-9 TRON snapshots of different weight functions at 600ms are shown, and all TRON snapshots are under the same color scale. Figure 6-9They are linear weight function, single-exponential weight function 1 (formula 8), single-exponential weight function 2 (formula 9), and adaptive weight function (formula 10). pass Figure 6-8 It can be seen that both the linear weight function and the single-exponential weight function have boundary reflections of different intensities, while Figure 9 ...

Embodiment 3

[0096] In order to prove that the absorbing boundary proposed by this method has better absorbing performance than the existing boundary conditions. The conventional PML boundary condition, the conventional hybrid boundary condition and the boundary condition proposed by this method are tested respectively. The wave field simulation parameters are the same as those in Embodiment 2, and both hybrid boundary conditions use adaptive weight functions. The wave field snapshots at 350ms and 500ms are as follows Figure 11-22 shown. exist Figure 11-14 The 3D wavefield snapshots at 350 ms of the non-absorbing boundary condition, the conventional PML boundary condition, the conventional mixed boundary condition and the boundary condition proposed by this method, respectively, Figure 15-18 3D wavefield snapshots at 500 ms for non-absorbing boundary conditions, conventional PML boundary conditions, conventional mixed boundaries, and boundary conditions proposed by this method, respec...

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Abstract

The invention belongs to the technical field of seismic exploration, and particularly relates to a transmission boundary-based mixed absorption boundary method, which comprises the following steps of: 1, setting information such as a seismic source, a detection point and a seismic record; 2, calculating an internal calculation region (region I) and a transition region (region II) of a viscous acoustic wave field and a transmission wave field to obtain a wave field value; 3, calculating the internal calculation area and the transmission boundary to obtain a transmission boundary wave field value; and 4, constructing a weight function of the two-way and transmission functions, and calculating a final wave field result. Compared with a traditional absorption boundary, the method has the advantages that a good absorption effect can be obtained by only needing fewer absorption layers; a self-adaptive weighting function is introduced at the boundary, so that boundary reflection at the inner boundary and the outer boundary can be suppressed at the same time, and the absorption effect is further improved; the wave field value of the absorption area at the next moment can be obtained only by using the wave fields at the current moment and the previous moment at the boundary, simultaneous calculation of multiple threads is facilitated, and the time complexity is reduced.

Description

technical field [0001] The invention belongs to the technical field of seismic exploration, and in particular relates to a mixed absorbing boundary method for numerical simulation of viscous media in time domain. Background technique [0002] Seismic wave numerical simulation is to use computer to simulate the propagation of seismic wave in underground medium, which is helpful to correctly understand the shape and properties of underground medium. This technology is widely used in natural earthquake prediction and mineral resource survey, especially one of the most crucial links in seismic data processing. Since the underground medium is an inelastic medium, the viscous wave field simulation technique considering formation absorption and attenuation is more in line with the real situation. Among them, the wave field simulation technology (Zhu 2014) for solving fractional Lagrangian equations in the time domain is one of the most widely used technologies at present. However...

Claims

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Application Information

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IPC IPC(8): G01V1/28
CPCG01V1/28
Inventor 王宁石颖李松龄王维红宋利伟王银凤
Owner NORTHEAST GASOLINEEUM UNIV
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