Implementation method for mixed absorbing boundary condition applied to variable density acoustic wave equation

A technology of absorbing boundary conditions and absorbing boundaries, which is applied in the field of realization of mixed absorbing boundary conditions, can solve the problems of unsatisfactory and inapplicable effects of large-angle incident waves and corner-point incident waves

Active Publication Date: 2014-04-02
CHINA NAT OFFSHORE OIL CORP +1
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Problems solved by technology

The existing mixed absorbing boundary conditions use low-order one-way wave equations, and the effect of absorbing large-angle incident waves and corner incident waves is still not ideal. At the same time, the existing mixed absorbing boundaries are based on the assumption of constant density, which is not suitable for variable density. The sound wave equation

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  • Implementation method for mixed absorbing boundary condition applied to variable density acoustic wave equation
  • Implementation method for mixed absorbing boundary condition applied to variable density acoustic wave equation
  • Implementation method for mixed absorbing boundary condition applied to variable density acoustic wave equation

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[0101] Example: Figure 4 is a schematic diagram of the absorption effect of the combined strategy of single-layer AWWE and the modified 15° one-way wave equation for the numerical simulation of the acoustic wave field in a 2D homogeneous medium, Figure 4 (a) and Figure 4 (b) is a slice of the acoustic wavefield at the same moment in a homogeneous medium, and is shown on the same color scale, both using a single absorbing boundary layer. Figure 4 (a) Use AWWE to process edges, take 5 reference velocities equal to background velocities, and use 15° one-way wave equation to process angles, see step 1 for the implementation method; Figure 4 (b) A modified 15° one-way wave equation for edges and a 5° one-way wave equation for angles. It is clear that the combination of AWWE and the modified 15° one-way wave equation suppresses boundary and corner reflections more effectively than Figure 4 (b) A combination of middle and lower order one-way wave equations is better, Figur...

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Abstract

The invention relates to an implementation method for a mixed absorbing boundary condition applied to a variable density acoustic wave equation. The implementation method comprises the steps of dividing a whole simulation region into an internal region and a boundary region, calculating the wave field value of a sound wave of each absorbing boundary layer by using the variable density acoustic wave equation and a variable density AWWE (Arbitrary Wide-angle wave equation) respectively, and performing linear weighting on the two calculation results to obtain the wave field value of the sound wave of each absorbing boundary layer. On the basis of realizing a single variable density AWWE absorbing boundary layer and in 2D (2 dimensional) and 3D (3 dimensional) space coordinate systems, the wave field value of the sound wave of each absorbing boundary layer is calculated by respectively adopting a combination mode of processing edges of the variable density AWWE and processing angles of a modified 15-degree one-way wave equation, and a combination mode of processing faces of the variable density AWWE, the processing edges of the modified 15-degree one-way wave equation and the processing angles of a 5-degree one-way wave equation, and the mixed absorbing boundary condition of the variable density AWWE is realized. The implementation method can be widely applied to the numerical simulation of constant density and variable density acoustic wave equations.

Description

technical field [0001] The invention relates to a method for realizing a mixed absorption boundary condition, in particular to a method for realizing a mixed absorption boundary condition for a variable density acoustic wave equation. Background technique [0002] In the field of seismic exploration, wave equation numerical simulation technology is an important means to understand the law of seismic wave propagation. It can not only guide the interpretation of seismic data and the design of observation system, but also the basis of current popular processing technologies reverse time migration and full waveform inversion. The numerical simulation of the wave equation is usually carried out in a limited area, and there are artificial truncation boundaries outside the simulation area. If no special treatment is carried out, the boundary reflection will occur when the wave propagates to the truncated boundary, which will interfere with the normal reflection information of the s...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V1/28
Inventor 范廷恩李绪宣周辉马淑芳余连勇明君井涌泉董建华陈汉明张会来
Owner CHINA NAT OFFSHORE OIL CORP
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