各向同性弹性波随机边界逆时偏移  

Elastic reverse time migration in isotropic medium based on random boundary

作　　者：吴国忱 秦海旭 

机构地区：[1]中国石油大学地球科学与技术学院,青岛266580

出　　处：《地球物理学进展》2014年第4期1815-1821,共7页Progress in Geophysics

基　　金：国家973项目多元多尺度地球物理信息映射关系及反演(2013CB228604)资助

摘　　要：叠前地震逆时偏移是目前公认地震成像的有效途径.声学介质逆时偏移已经成熟,弹性波逆时偏移研究相对较少,本文研究了各向同性介质弹性波逆时偏移.传统逆时偏移由于存储量的巨大不便于实际应用.本文针对逆时偏移存储量大的缺点,采用随机边界条件,用计算换存储减少了存储量.首先从波动方程出发,推导了各向同性介质弹性波逆时偏移高阶有限差分算子;其次运用随机边界逆时偏移的流程进行逆时偏移;最后采用传统的拉普拉斯滤波的方法消除低频噪音.模型试算表明,采用随机边界得到逆时偏移结果与常规有限差分得到的逆时偏移结果差别较小,证明了该方法的正确性.Pre-stack reverse time migration is a very useful tool for seismic imaging.Acoustic medium reverse time migration has been matured,but elastic wave reverse time migration is just beginning,so this paper studies the isotropic medium elastic wave reverse time migration.Traditional reverse time migration is not convenient to practical application because it is need lager storage.Aiming at the problem of massy memory demand,we adopt the random boundary condition which reduces the memory demand but sacrifice the computation cost.First,isotropic medium elastic reverse time migration of high order finite difference operator from the wave equation is deduced.Then using random boundary reverse time migration processing to do reverse time migration.Last using the traditional method of Laplace filter to eliminate the low frequency noise. Model trial showed that the difference between the migration result from the method of random boundary condition and from the traditional reverse time migration is very small and could be overlooked,which proved the method is correct.

关 键 词：弹性波逆时偏移 随机边界 有限差分 拉普拉斯滤波 各向同性介质 

分 类 号：P631[天文地球—地质矿产勘探]