基于波前构建法的TTI介质射线追踪  

Raytracing in TTI media using wavefront construction

作　　者：白海军[1,2] 孙赞东[1] 王学军 

机构地区：[1]中国石油大学(北京)地质地球物理综合研究中心,北京昌平102249 [2]中海油深圳分公司研究院,广东广州510240 [3]东方地球物理公司研究院,河北涿州072751

出　　处：《石油地球物理勘探》2011年第A01期1-6,163+166,共6页Oil Geophysical Prospecting

基　　金：国家重点基础研究发展规划973项目(2011CB201103)"中国西部叠合盆地深部有效碳酸盐岩储层形成机制与分布预测";国家油气重大专项(2011ZX05004003)"海相碳酸盐岩储层地震描述与油气藏有效预测技术研究"资助

摘　　要：射线(群速度)方向与旅行时梯度(相速度)方向不一致,使得TTI介质的射线追踪变得非常困难。传统的以弹性参数表示的各向异性射线追踪系统比各向同性条件下要复杂得多,而且在每一步都要求通过解特征值问题来计算极化矢量,使得整个射线追踪过程相当耗时。鉴于此,本文引入一种用相速度和群速度重构的射线追踪系统,该射线追踪系统与各向同性条件下的完全相似,从而简化了TTI介质的射线追踪问题。在综合考虑多种走时计算方法的优劣后,选择波前构建法进行射线追踪和波前传播的计算。将简化的射线追踪系统与波前构建法的优势相结合,得到了简单、高效的TTI介质射线追踪方法,并通过模型试算验证了此法的可行性。The direction of ray(group velocity) and that of traveltime gradient(phase velocity) are not the same,making raytracing in TTI media rather difficult.The traditional raytracing system formulated in terms of elastic parameters in the anisotropiy is more complicated than that in the isotropic case.Furthermore,an eigenvalue problem for polarization vectors has to be solved at every ray step.As a result,raytracing in TTI media is always time consuming.Considering all the difficulties mentioned above,a kind of raytracing system formulated in terms of phase velocity and group velocity,which is similar to the expressions for isotropic media,is introduced in this paper and raytracing in TTI media is largely simplified consequently.After a comprehensive consideration for many traveltime calculation algorithms,the wavefront construction method is chosen to trace rays and propagate wavefront.By combination of simplified raytracing system and the merits of wavefront construction method,a simple and efficient method for raytracing in TTI media is realized and several numerical models are used to demonstrate its feasibility.

关 键 词：TTI介质 射线追踪 射线追踪系统 波前构建法 

分 类 号：P631[天文地球—地质矿产勘探]