程函方程差分法层析成像

Crosshole seismic tomography based on a finite difference solution of the eikonal equation

地质矿产部南京石油物探研究所, 南京210014

Research Institute of Geophysical Prospecting for Pctrolcum, Nanjing 210014

在程函方程差分解法的基础上, 本人曾给出了在已知二维空间网格点上的初至走时来一次求出所有接收点至激发点之间的地震初至波射线路径, 从而利用瞬时迭代重建技术(SIRT)实现了任意两维地下介质速度分布情况下的弯曲射线法层析成像反演算法。利用这种方法通过对大量数学模型资料、物理模型资料及吉林地区野外井间地震资料的处理, 取得了较好的实际效果, 证明这种先由差分法求解程函方程, 再由得出的时间场做炮点－检波点射线追踪, 进而应用SIRT技术反演是层析成像反演方法中行之有效的手段之一。

Based on finite difference solution of the two dimensional eikonal cquation, the author has presented a paper on a fast raytracing method of seismic first arrival raypaths for all rcceivers to its source from first arrival times on discrete grids. A bend ray seismic tomographic invcrsion method suitablc to any velocity distribution has beon foundcd by using a simultaneous image reconstruction technique (SIRT). By this method,we have processed many mathematical model data, physical laboratory model data and field crosshole seismic data from Jilin province in northcast China,and obtaincd very good resulis,These results have shown that firstly solving the 2-D eikonal equation,then tracing the raypath from known times and finally invcrsion by SIRT technique is an effective means for seismie tomography.