基于归一化波场拆分互相关成像条件的叠前逆时偏移方法  

Pre-stack reverse-time migration based on normalized wavefield decomposition cross-correlation imaging condition

作　　者：丁亮[1,2] 刘洋[1,2] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)CNPC物探重点实验室,北京102249

出　　处：《石油地球物理勘探》2012年第3期411-417,355+518,共7页Oil Geophysical Prospecting

基　　金：国家自然基金项目(40839901);国家科技重大专项课题(2011ZX05024-001)

摘　　要：本文基于高阶精度有限差分算法实现了声波方程叠前逆时偏移,并引入完全匹配层吸收边界来消除边界反射能量。基于模拟数据,通过对波场拆分互相关成像条件与震源能量归一化互相关成像条件进行分析,尝试结合两者分别在噪声消除以及改善成像振幅方面的优势对现有成像条件做进一步改进。通过模拟数据和实际资料的试处理,表明改进后的成像条件有效地消除了偏移噪声,同时获取的成像振幅能够提供相对于常规方法更为准确的界面反射系数信息。Reverse-time migration(RTM) based on two-way wave equation,has many advantages.Comparing with the Kirchhoff migration and one-way wave equation migration which are widely used in practice,RTM has a simple principle,it obtains imaging accurately with no angle constraints,and it can be adapted to arbitrary velocity model and able to handle imaging point with multi travel time etc.Recently,along with the rapid development of computer technology,RTM has drawn a lot of attentions.In this article,acoustic wave equation pre-stack RTM based on high-order finite difference algorithm is implemented.Perfectly matched layer(PML) absorbing boundary condition is used to absorb boundary reflections.According to analyses of the wavefield decomposition cross-correlation imaging condition and the source-normalized cross-correlation imaging condition,we attempt to improve the imaging condition by combining with the advantages of both.At last,theoretical and real data validate that this method can eliminate noises better and provide more relatively accurate information of reflection coefficients.

关 键 词：声波方程 逆时偏移 有限差分 完全匹配层 波场拆分 归一化 成像振幅 

分 类 号：P631[天文地球—地质矿产勘探]