起伏地表下基于抛物插值的最短路径射线追踪

基于射线理论的初至波走时层析静校正是解决复杂地表静校正问题的实用方法，其核心技术是射线追踪。基于抛物插值的最短路径射线追踪方法利用最短路径、动态网格和抛物旅行时插值实现了初至波射线路径的追踪和初至走时的准确求取，但起伏地表条件下起伏界面的存在给射线追踪带来了许多问题。为此，对基于抛物插值的最短路径射线追踪算法进行了改进，将起伏地表及地下界面精确地投影到部分网格节点上，实现了起伏地表下的初至波路径的射线追踪。通过模型和实际资料试算，证明了改进后的算法适用于起伏地表条件下的近地表层析速度建模和静校正量计算。

The first-arrival traveltime tomography static correction is a practical method to solve the problem of seismic data statics in complex near-surface.The core of the traveltime tomography basing on ray theory is raytracing.The shortest path raytracing based on parabolic traveltime interpolation uses shortest path,dynamic grid and parabolic interpolation to realize the first-arrival wave path raytracing and traveltime calculation.Under the irregular topography condition,the fluctuating interface causes many problems to raytracing.Firstly,we discuss how to modify the algorithm of raytracing to adapt the irregular topography.Then,we use the raytracing method for velocity modeling and calculating static correct value.Finally,tests on near-surface tomography of model and real data in irregular topography prove the effectiveness and feasibility of our approach.