摘要
Abstract
Seismic migration started out with a humble goal:trying to position lateral subsurface reflectors accurately enough for exploration with a drill bit.Over time,migration became more ambitious.With the advent of prestack depth migration,we began to think of seismic imaging as a process to provide a picture of the interior of the earth.We give an overview of prestack depth migra-tion,its theoretical foundations,application status,and technological evolution in response to production demands.Based on true amplitude migration theory,we review all the main trends of depth imaging techniques,such as Kirchhoff migration,beam migra-tion,and one-way wave equation migration.Particularly,we focus on reverse time migration (RTM),introducing its theory and ap-plications.We address a few important topics in RTM development,such as common imaging gather output,anisotropic migration, anelastic attenuation compensation,migrating simultaneous shooting records,ghost compensation within an RTM,and the imaging of multiples.We then discuss the theory of least-squares migration (LSM),its implementations,and the main practical issues,and compare migration deconvolution with LSM.Full waveform inversion (FWI)has been a hot topic in exploration geophysics in the past decade.We show that true amplitude migration theory plays an important role in building up the connection between imaging and inversion,and an inversion-based true amplitude RTM stays as the kernel of a FWI.We discuss several challenging topics in FWI implementation,such as cycle skipping caused by missing low frequencies in data,FWI based on only travel-time information, reflection-based FWI,and multi-parameter FWI.Much progress has been made to solve those problems.A fully automated FWI will significantly simplify processing workflow,greatly reduce production cost,and improve imaging resolution.More importantly,it will help geophysicists to approach the ultimate goal:rendering quantitatively accurate earth models with high resolution.关键词
叠前深度偏移/真振幅偏移/逆时偏移/Kirchhoff偏移/共成像点道集/各向异性偏移/非弹性衰减补偿/多次波偏移/鬼波/最小二乘偏移/偏移反褶积/全波形反演/跳周现象/多参数反演分类
天文与地球科学
