The application of seismic first arrival ray tracing tomography static in the complicated near surface area.

在复杂地表和复杂构造地区,静校正问题突出。为此,根据目前静校正存在的问题和实际需要,进行了地震初至波射线层析成像方法的研究。给出了初至旅行时层析成像方法的基本原理,包括近地表模型的建立、射线路径和初至时间的计算、反演方程的建立以及共轭梯度反演方法等。其中提出的对复杂介质采用动态网络最短路径射线追踪方法,克服了同类方法得到的射线路径呈之字形、计算出的旅行时比实际旅行时系统偏大的缺陷。利用非线性共轭梯度优化方法来实现初至旅行时层析反演,反演过程稳定收敛。利用理论模型和实际资料对方法进行了验证,结果表明,采用上述方法求取复杂地区的静校正量,静校正效果很好,剖面的品质得到了较大的改善。Static technique plays a key role in seismic data pro- cessing,especially in complicated near surface area such as mountain,sand dune.Tomography imaging method from seismic first-arrival ray is studied on the problem in static and its development.The paper presents the fundamental principle of first arrival travel time tomography imaging, including establishment of the near surface model,ray trac- ing and calculation of the first arrival time,building of the inversion equation and conjugate gradient inversion meth- od.Of which based on the shortest path algorithm,a shor- test path ray tracing method with dynamic networks is de veloped.Nonlinear conjugate gradient optimize is used to realize the first arrival tomography inversion.The process of inversion is convergent.The real data shows that this al- gorithm is accurate in computing the velocity and the static value in complicated near surface area.The quality on the section has been improved