完全匹配层人工边界条件中的衰减因子分析

Analysis on attenuation factor in the processing of artificial boundary conditions of PML

(1.成都理工大学地球物理学院,四川成都610059;2.油气资源与勘探技术教育部重点实验室(长江大学),湖北荆州434023)

Gao Gang,College of Geophysics,Chengdu University of Technology,Chengdu 610059,China

为了得到地下地质体的地震波场响应特征，需要进行三维地震波场数值模拟，但其计算量很大。利用有限差分方法进行数值模拟时，减少
计算量的途径有两种：一是差分格式设计；另一种是边界条件的选择。从完全匹配层（PML）吸收边界条件的原理出发，总结了目前PML人工边
界条件中的常用衰减函数，说明了衰减函数设计的重要性。数值模拟结果表明，余弦型吸收衰减因子的波场模拟效果要优于其它吸收衰减因子
。

3D seismic numerical simulation can obtain the more realistic wavefield response of subsurface geologic bodies, but the
computation amount is huge.During numerical simulation by using finite difference method,there are two ways to reduce
computation amount,one is difference form design,the other is the selection of boundary condition.Starting from the
principles of Perfect Matched Layer (PML) absorption boundary condition,the conventional attenuation functions of the PML
artificial boundary conditions were summarized,and the importance of attenuation design was elaborated.Numerical simulation
results indicate that the wavefield simulation result of cosine absorption is better than other absorption attenuation
factors.

10.3969/j.issn.1000-1441.2001.05.002