结合基准面重建的叠前时间偏移方法  

Prestack time migration incorporated with redatuming

作　　者：董春晖[1,2] 张剑锋[2] 

机构地区：[1]中国石油大学(北京)资源与信息学院,北京102249 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学报》2010年第10期2435-2441,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金重点项目(40930422);国家科技重大专项(2008ZX05008-006)资助

摘　　要：提出了一种结合虚拟界面、瑞利积分和相移法的混合的基准面重建方法.通过与叠前时间偏移方法结合,形成了针对起伏地表采集数据的叠前时间偏移方法和新流程.该方法能正确考虑波在近地表传播的实际路径,克服了高速层出露时静校正方法的误差;它也能自己确定虚拟层速度,避免了现行基于波场延拓的基准面重建方法需要准确近地表速度的困难.文中分别用近地表存在明显低速层和近地表有高速层出露这两类模型的理论数据,验证了所发展方法和流程的有效性.We present a new redatuming technique based on the virtual surface, Rayleigh integral, and phase-shift method. Combining the redatuming technique with the pre-stack time migration results in a pre-stack time migration scheme and workflow which can be applied to the dataset acquired at the irregular surface. The resulting scheme can correctly model seismic wave propagation in the complex near surface, thus avoiding the errors related to static correction when high speed media are exposed on the surface. Moreover, we give a method to determine the reasonable velocity of virtual medium. No prescribed near surface velocity model, which is key for the conventional redatuming technique, is needed. Two synthetic datasets from models with and without low speed media near the surface are used to test the proposed scheme.

关 键 词：叠前时间偏移 起伏地表 野外静校正 基准面重建 

分 类 号：P631[天文地球—地质矿产勘探]