摘要
OBS数据分析时,常通过正演计算来辅助识别数据上的震相,这就需要在给定的速度模型上计算指定炮检点的射线路径。本文基于层状均匀介质模型实现了一种简单快速,并且适用于任意纵波和横波路径的算法。该算法基于费马原理和最优化方法,首先给定炮检点射线旅行时的目标函数,由费马原理可知,该目标泛函的极小值对应的射线路径就是真实的路径。然后利用最优化方法来获得目标泛函的极小值。对于水平层状均匀介质模型,可通过令目标函数的梯度等于零来获得射线的路径;而对于倾斜界面以及界面为曲线的模型,则通过非线性最优化方法来极小化目标函数。结果表明,该方法实现简单,能够快速地计算出射线路径,数值例子证明了其有效性。同时,该方法不仅适用于纵波射线路径,还适用于横波射线路径。
Seismic forward modeling calculation is commonly used to help identifying the wave phase when analyzing OBS data,which needs to compute the ray path through the position of given sources and receivers in the given model.Based on the Fermat principle and the optimal method,the paper uses the simple and layered homogeneous model,and implements a simple and effective method which is proved to achieve easily and calculate the ray trace quickly.It can trace ray-path of compressional wave and converted wave.An objective function that defines the travel time is firstly defined in the method,and the path that corresponds to the minimal value of the function is the true ray path.Thus the minimal value of the function is attained by using optimal method.For horizontal layered homogeneous model,the minimal value can be obtained by letting the gradient equal zero.For other cases,nonlinear optimal method is used to obtain the minimal value.Consequently,numerical examples show the effectiveness of the method.The approach can be used to trace not only compressional wave ray path but also ray path of converted wave.
作者
秦越
刘斌
Qin Yue;Liu Bin(Key Laboratory of Marine Mineral Resources,Ministry of Natural Resources,Guangzhou Marine Geological Survey,Guangzhou Guangdong 511458,China;Southern Marine Science and Engineering Laboratory,Guangzhou Guangdong 511458,China)
出处
《工程地球物理学报》
2022年第3期376-385,共10页
Chinese Journal of Engineering Geophysics
基金
南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(编号:GML2019ZD0207)
中国地质调查局项目(编号:DD20221714,DD20191007)。
