基于Poynting矢量和方向行波波场分离的逆时偏移成像条件  

Reverse-time migration imaging conditions based on Poynting vector and directional one-way wave field separating

作　　者：韩文功 王江川[2] 李振春[2] 孙小东[2] 陈静[2] 

机构地区：[1]中石化石油工程地球物理有限公司,北京10000 [2]中国石油大学(华东),青岛266580

出　　处：《地球物理学进展》2015年第6期2660-2665,共6页Progress in Geophysics

基　　金：国家自然科学基金(41204086);国家科技重大专项课题(2011ZX05006-002)联合资助

摘　　要：叠前逆时偏移在解决陡倾角构造和复杂速度模型成像上展示出了极佳的优越性,但是低频噪声的存在严重影响了成像的质量.Poynting矢量的方向代表了介质中地震波的传播方向,根据Poynting矢量可以计算出反射角并且可将地震波场分离成上行波、下行波.本文提出了一种新的成像条件,同方向上下行波互相关成像噪声和大角度成像噪声可以得到较好的压制.相比于常规的互相关成像条件,该方法简单易行,所需额外的计算量和存储量极小,将该成像条件应用在Marmousi模型上,偏移结果显示低频噪声得到很好的压制.Pre-stack reverse-time migration shows great superiority in dealing with steep dip angle structures and complex velocity models,but the low frequency noise seriously affects the quality of imaging. The reflect angle can be calculated by the Poynting vector,the direction of which indicates that of the propagation of seismic wave, and meanwhile seismic wave field can be separated into up-going one and down-going one.This paper proposes a new imaging condition,by using which the imaging noise caused by the cross-correlation of the up-going wavefield and the down-going one in the same direction,as well as wide angle noise can be well suppressed. Compared with the conventional crosscorrelation imaging conditions,the new imaging condition is easy to realize,the extra calculation and storage are both very small.The new imaging condition is applied in Marmousi model and the migration results shows that the low frequency noise is well suppressed.

关 键 词：逆时偏移 Poynting矢量 波场分离 成像条件 

分 类 号：P631[天文地球—地质矿产勘探]