石油地球物理勘探2024，Vol.59Issue(3)：514-522,9.DOI:10.13810/j.cnki.issn.1000-7210.2024.03.014
基于变差分系数的变网格弹性波全波形反演
Full-waveform inversion of elastic waves in variable grids based on variable difference coefficients
摘要
Abstract
Full-waveform inversion fully utilizes all the information of seismic wave propagation,including am-plitude,phase,and travel time,which can obtain inversion results with higher resolution and accuracy com-pared with travel time tomography.When the velocity in the shallow layer of the medium is low,fine grids are usually used to sample the low-velocity layer,so as to ensure the accuracy of forward modeling.However,sub-dividing the entire model into finer grids will increase computational complexity and storage requirements,and oversampling will occur in the high-velocity regions of the model.These problems are further amplified in the process of full-waveform inversion.To address these issues,this study introduced a finite difference forward modeling method of the elastic wave equation in variable grids based on variable difference coefficients.Firstly,the difference coefficient of variable grid wave field simulation was derived based on Taylor expansion,and the variable grid wave field simulation was realized.Secondly,the forward modeling method of variable difference coefficients was applied to the forward modeling,residual backpropagation,and wave field reconstruction of the full-waveform inversion,and the full-waveform inversion of elastic waves in variable grids based on the variable difference coefficient was realized.In the full-waveform inversion,the multi-scale inversion strategy and the conventional conjugate gradient method were used for the iterative solution.The fine grids were used to divide shallow low-velocity layers,and coarser grids were used to divide the middle and deep layers with high ve-locity,which ensured the accuracy of inversion for the shallow layers while avoiding oversampling in the middle and deep layers.The inversion results of the model data demonstrate that the full-waveform inversion in variable grids based on variable difference coefficients can effectively characterize the low-velocity anomalies compared with full-waveform inversion in uniform coarse grids.The test of noisy data shows that the proposed full-waveform inversion method has strong noise resistance.关键词
弹性波/全波形反演/变差分系数/变网格正演/有限差分Key words
elastic wave/full-waveform inversion/variational difference coefficient/forward modeling of variable grids/finite difference分类
天文与地球科学引用本文复制引用
张红静,贺慧丽,孙文博,孙鹏远,李红辉,周辉..基于变差分系数的变网格弹性波全波形反演[J].石油地球物理勘探,2024,59(3):514-522,9.基金项目
本项研究受核资源与环境国家重点实验室开放基金项目"井震结合下基于谱蓝化—有色反演的松辽盆地南部姚家组砂岩型铀矿预测方法研究"(2022NRE16)、东华理工大学博士科研启动基金项目"可控震源扫描技术及高阶谐波消除方法研究"(DHBK2019083)和中国石油天然气集团公司前瞻性基础性项目"物探岩石物理与前沿储备技术研究"(2021DJ3506)联合资助. （2022NRE16）
