平面波最小二乘逆时偏移方法的优化  

Optimization of plane wave least squares reverse time migration

作　　者：田文彬 张凯[1,2] 李振春 TIAN Wenbin;ZHANG Kai;LI Zhenchun(School of Geosciences China University of Petroleum (East China),Qingdao 266580 ,China;Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology ^Qingdao 266011 ,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]海洋国家实验室海洋矿产资源评价与探测技术功能实验室,山东青岛266071

出　　处：《石油物探》2019年第2期245-252,共8页Geophysical Prospecting For Petroleum

基　　金：国家油气重大专项(2017ZX05032-003-002);山东省自然科学基金(ZR2017MD014);山东省重点研发计划项目(2018GHY115016);中国石油大学(华东)自主创新科研计划项目(17CX02052)共同资助~~

摘　　要：基于平面波编码的最小二乘逆时偏移(PLSRTM)具有较高的计算效率,而且能够通过降低超道集之间的相干性压制串扰噪声,但其成像结果中存在偏移假象,影响了最终的成像精度和收敛速度。为此,对平面波最小二乘逆时偏移方法进行了优化,利用局部倾角获取构造信息计算构造导向滤波算子,并将其作为正则化算子引入平面波最小二乘逆时偏移,在不影响构造信息的前提下,压制每次迭代梯度的偏移假象,从而提高观测数据与计算数据的匹配程度,最终达到加快收敛速度和提高成像精度的目的。二维简单模型和HESS模型数据试算结果表明:该方法可以在提高计算效率的同时压制串扰噪声,消除偏移假象,加快收敛速度,提高复杂构造的成像精度。Plane wave least squares reverse time migration based on shot coding can improve computational efficiency and suppress crosstalk noise.However,some migration artifacts exist that could affect final imaging accuracy.A structure-oriented filter operator can suppress random noise using information about the structural dip. First, structural information is obtained by each iteration gradient from a local dip.Based on this,the structure-oriented filter operator is then established and introduced into the plane wave least squares reverse time migration as a regularization operator.This method can preserve information about structures and suppress migration artifacts in each iteration,thus improving the matching degree between the observation data and calculation data, accelerating the convergence,and improving the imaging accuracy.Tests on both a simple model and HESS model showed that this method can suppress crosstalk noise and migration artifacts,accelerate the convergence,and improve the computational efficiency and imaging accuracy of complex structures.

关 键 词：平面波编码 构造导向滤波算子 最小二乘逆时偏移 偏移假象 串扰噪声 成像精度 平面波分解滤波器 

分 类 号：P631[天文地球—地质矿产勘探]