黏声TTI介质中纯qP波逆时偏移成像方法  

Reverse time migration in viscoacoustic TTI media based on pure qP wave equation

作　　者：慕鑫茹 黄建平[1,2] 黎国龙 毛强 MU Xinru;HUANG Jianping;LI Guolong;MAO Qiang(School of Geosciences in China University of Petroleum(East China),Qingdao 266580,China;Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266071,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：《中国石油大学学报（自然科学版）》2023年第2期44-52,共9页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：“十四五”重大项目(2021QNLM020001);国家重点研发计划(2019YFC0605503C);优秀青年科学基金项目(41922028);国家创新群体项目(41821002);中石油重大科技项目(ZD2019-183-003)。

摘　　要：地下介质广泛存在黏滞性及各向异性特征,使得地震波在传播过程中发生相位畸变和振幅衰减。若在偏移成像时不对这些黏滞性及各向异性影响进行校正,则会引入成像噪声而降低成像分辨率。针对上述问题,首先将黏滞性引入到TTI介质波动方程,得到一种黏声TTI介质纯qP波波动方程。然后,基于新推导的黏声TTI介质波动方程,发展相应的逆时偏移成像方法。由于黏滞性补偿过程中能量会被放大,波场中指数增加的高频噪声易造成波场传播不稳定。鉴于此,将正则化算子引入到逆时能量补偿过程,以压制波场中的高频噪声。结果表明:新提出的黏声TTI介质逆时偏移成像算法可校正相位畸变,补偿能量衰减,实现对含黏滞性及各向异性介质的高精度成像。During seismic wave propagation,phase distortion and amplitude attenuation occur due to the anisotropy and viscosity of the underground media.Failure to correct for these effects during migration imaging can lead to reduced imaging resolution and the introduction of imaging noise.To address this,we introduce viscosity into the anisotropic wave equation and obtain a pure qP wave equation in viscoacoustic TTI media.We then develop a reverse time migration imaging method based on the wave equation of viscoacoustic TTI media.The exponential increase of high-frequency noise in the wave field during viscosity compensation can cause wave propagation instability.To mitigate this issue,we introduce a stable regularization operator into the energy compensation process to suppress the high-frequency noise.Numerical tests show that the new wave equation accurately simulates wave propagation characteristics in viscous and anisotropic media.In addition,the proposed reverse time migration imaging algorithm for viscoacoustic TTI media corrects travel time error and phase distortion,compensates for energy attenuation,and achieves high-precision imaging of underground complex media with anisotropy and viscosity.

关 键 词：黏声TTI介质 有限差分-伪谱法 正则化算子 逆时偏移 

分 类 号：P631.4[天文地球—地质矿产勘探]