Three-dimensional Acoustic Numerical Simulation Method Based on pml Absorbing Boundary

Abstract

The invention discloses a three-dimensional acoustic wave numerical simulation method based on PML absorption boundary, which mainly includes the following steps: s1. Applying a regular grid in the internal calculation area, defining the wave field pressure only on the integer nodes of the regular grid; The staggered grid is applied in the area, the wave field pressure is defined on the integer nodes of the staggered grid, and the velocity component and medium density of the particle are defined on half the nodes of the staggered grid; s2, the second-order hyperbolic partial differential wave equation is used in the internal calculation area Update the wave field pressure value; use the first-order stress velocity-equation to calculate the velocity component of the particle and the wave field pressure value in the PML absorption region. The method of the invention not only reduces the memory requirement, expands the model scale that can be simulated, but also makes the PML boundary processing more concise. The method of the invention is especially suitable for numerical simulation of seismic wave field or reverse time migration in the field of oil and gas exploration.

Description

technical field [0001] The invention belongs to the field of oil and gas exploration, and relates to a three-dimensional acoustic wave numerical simulation method based on PML absorption boundaries. Background technique [0002] In the 3D acoustic wave simulation based on the PML absorption boundary, the calculation area is divided into two parts: one is the internal calculation area, and the other is the PML absorption area, such as figure 2 As shown in , the gray shaded part of the boundary represents the PML absorption area, and the internal blank is the internal calculation area. ① indicates the corner boundary of the PML absorption area, and ② indicates the edge boundary of the PML absorption area. [0003] Taking the model with N×N×N three-dimensional grid and PML boundary thickness as M grid points as an example, there are two simulation methods: [0004] Method 1: Use a regular grid, that is, all physical quantities and pressure values ​​are defined on the grid node...

AI Technical Summary

Problems solved by technology

[0009] It can be seen that the technical problem of the above method 1 is that too many auxiliary variables are introduced, and the PML boundary processing is more complicated;

[0010] Although the above method 2 is beneficial to the processing of the PML boundary, it needs to define the pressure value and particle velocity in the entire grid at the same time, and the memory usage increases significantly.

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