浅论真振幅权函数的数值计算  

Elementary discussion on numerical calculation of true amplitude weight function

作　　者：付利敏[1,2] 孙建国[1,2] 张东良[1,2] 

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026 [2]国土资源部应用地球物理综合解释理论开放研究实验室,长春130026

出　　处：《世界地质》2011年第4期682-689,共8页World Geology

基　　金：国家重点基础研究发展计划(973)课题(2007CB209603);国家自然科学基金项目(40574052);国家十二五重大研究专项(2011ZX05025-001-05)联合资助

摘　　要：真振幅权函数是Kirchhoff偏移的核函数,数值计算方案与其表达形式有关。为探讨Kirchhoff型真振幅加权函数的最优计算方案,对出现在文献中典型的3种表达形式的权函数的数值实现流程进行了对比分析。结果表明:基于格林函数振幅的计算方案需要进行动力学射线追踪,最为耗时;基于旅行时和基于坐标与慢度的计算方案仅需运动学射线追踪;基于旅行时的计算方案把权函数完全表述成旅行时导数的形式,方便易行,但算法的稳定性对旅行时的依赖度很高;而基于坐标与慢度的计算方案对复杂模型有很好地适应性。此外,文中还特别讨论了2.5D介质下基于旅行时的权函数数值计算方案并进行了实现。True amplitude weight function is the kernel function of Kirchhoff-type migration, its numerical so- lution relies on its expression form. In order to explore the optimal scheme of Kirchhoff-type true amplitude weight function, the authors compare the numerical realization flow of three typical forms of weight function in relevant lit- eratures. The result shows that, the approach based on Green function amplitude needs dynamic ray tracing, which is the most time-consuming; the approaches based on travel time and coordinate together with slowness vector only need kinematic ray tracing. The approach based on travel time expresses the weight function to travel time deriva- tive, which is convenient and simple, but the stability relies on travel time; the approach based on coordinate to- gether with slowness vector has a good adaptability to the complex model. Besides, the authors discuss and carry out the weight function calculation based on travel time in 2. 5D media.

关 键 词：真振幅 权函数 Kirchhoff偏移 旅行时 

分 类 号：P631.4[天文地球—地质矿产勘探]