层间多次波傅里叶有限差分偏移成像  

Fourier finite-difference migration of internal multiples

作　　者：黄建东 胡天跃[1] 王尚旭[2] HUANG JianDong;HU TianYue;WANG ShangXu(School of Earth and Space Sciences,Peking University,Beijing 100871,China;State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;Department of Mathematical Sciences,Tsinghua University,Beijing 100084,China)

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]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 [3]清华大学数学科学系,北京100084

出　　处：《地球物理学报》2022年第11期4394-4403,共10页Chinese Journal of Geophysics

基　　金：国家重点研发计划(2018YFA0702503);国家自然科学基金项目(41674122)联合资助.

摘　　要：传统地震偏移方法仅利用一次反射波进行偏移成像,多次波对其来说是一种噪声,在成像前需要将多次波去除.然而多次波偏移比一次反射波偏移拥有更高的照明度,可以提高地震成像的精度.通过修改传统傅里叶有限差分偏移方法,将层间多次波作为输入数据,可将层间多次波成像.本文提出的层间多次波傅里叶有限差分偏移方法,通过波场延拓和全波场方法获得上行波场和下行波场,利用层间多次波成像条件对不同阶数的层间多次波分别进行成像,正传波场和反传波场在零时刻进行互相关.数值实例验证了本文方法的正确性和实用性,表明层间多次波成像可以突出盐丘体的同相轴,恢复盐下的构造信息,弥补传统成像方法的不足,提高地震偏移成像分辨率,有效地为地下提供额外照明.The conventional seismic migration method employs primaries to perform migration imaging only and the multiples,regarded as a kind of noise,need to be removed before imaging.However,the migration of multiples has a higher illuminance than the imaging for primaries,which can improve the accuracy of seismic imaging.The modified Fourier finite-difference migration uses internal multiples as input data to image the internal multiple.The Fourier finite-difference migration method of internal multiples presented in this paper applies wavefield extrapolation and full-wavefield method to compute the upward and downward wavefields and then uses cross-correlation condition to image the internal multiples of different orders separately.The forward and reverse wavefields are cross-correlated at t=0.Numerical examples verify the correctness and practicability of the proposed method and show that internal multiples imaging can highlight the events of salt,restore the structural information under the salt,make up for the shortcomings of the conventional migration methods,significantly improve seismic imaging resolution,and effectively provides additional illumination for the underground.

关 键 词：层间多次波成像 傅里叶有限差分偏移 可控多次波场 单程波方程 

分 类 号：P631[天文地球—地质矿产勘探]