基于三角域快速行进法的地震波走时计算

Seismic Travel-time Computation Using Triangulated Fast Marching Method

地震波走时计算是地震资料解释处理技术的重要组成部分,本文根据复杂地层构造中速度场分布的特点,设计了一种采用快速行进法基于三角网格的走时计算方法,针对计算效率优化和快速行进法在三角域上的计算格式进行了重点的研究,并根据地层限定条件对速度场进行网格剖分,在三角网格上用快速行进算法计算各点走时。与基于矩形网格的差分方法相比,该方法不需要对速度场边界进行任何平滑,无须通过细分网格来提高计算精度;可根据不同地质构造的复杂度进行变网格大小的剖分,网格剖分数目相对较少。最后通过计算实例进行了验证。

Travel-time computation is an important technique of seismic data process. According to the traits of complex velocity model, we present a travel-time computation using triangulated fast marching method. First, we get a triangulated mesh using 2d con- strained triangulation. Then the triangulated fast marching method is introduced to compute travel-time. Compared to other finite difference wavefront computation method based on rectangle cell parameteration, this method based on triangle cell parameteration doesn＇t need any flatness on the interface of velocity model to improve the precision. It presents the complex velocity model with less cells through control the size of triangle on different part. The results of computation on Marmousi model demonstrate correctness of the proposed methods.