基于Poynting矢量分解成像条件的最小二乘逆时偏移  

Least-squares reverse time migration based on Poynting vector decomposition imaging condition

作　　者：向晨 XIANG Chen(SINOPEC Geophysical Research Institute,Nanjing 211103,China)

机构地区：[1]中国石化石油物探技术研究院,南京211103

出　　处：《物探化探计算技术》2023年第2期169-176,共8页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：国家自然科学基金企业创新发展联合基金(U19B6003)。

摘　　要：最小二乘逆时偏移在实现复杂介质高精度成像中有着巨大优势,利用梯度引导方法进行迭代求解可以获取高分辨率的地震成像结果。然而由于梯度中含有严重的低频噪音,影响着迭代收敛速度和最终的成像效果,其实用性仍然存在挑战。这里利用Poynting矢量可以表示波的传播方向,将地震波分离成上、下、左、右行波,去除梯度中的低频噪音项,构建一个新的梯度。相比于常规的最小二乘逆时偏移,其计算增加量几乎可以忽略,但是改善了梯度的质量和最后的成像效果,模型试算结果也表明本文方法具有更好的保幅特性,同时加快了收敛速度。Least-squares reverse time migration(LSRTM)has great advantages in realizing high-precision imaging of complex media.In the iterative solution process using the gradient guidance method,the gradient has low-frequency severe noise,which affects the quality and efficiency of the final imaging.Poynting vector can represent the propagation direction of the wave and separate the seismic wave into up-going,down-going,left-going,and right-going waves.In this abstract,the separated up-going,down-going,left-going,and right-going waves are used to remove the low-frequency noise items in the gradient and construct a new gradient.Compared to the conventional least-squares reverse time migration,the increase in calculation amount is almost negligible.However,the quality of the gradient and the effect of the final imaging are improved,and the convergence speed is accelerated at the same time.

关 键 词：Poynting矢量分解 最小二乘 逆时偏移 低频噪音 

分 类 号：P631.4[天文地球—地质矿产勘探]