Application Study Of Reverse Time Migration Technique In TI Media

In recent years,with the development of seismic exploration,the targets become more and more complex,which leads to a huge challenge to the imaging techniques.So the imaging techniques must be developed so that they can be adapted to the anisotropy,violent velocity variations and complex reservoir,etc.Reverse time migration(RTM)based on the two-way wave equation is the most accurate imaging technique,which can handle several types of waves with different propagation paths,has no dip limitation and can be adapted to both vertical and lateral velocity variations.However,there exists several flaws,such as complex waves that can not focus in right place,low frequency noise,weak amplitude of deep structure etc.,using conventional acoustic RTM technique in anisotropic deep reservoir imaging.To solve these problems,the dissertation mainly do the following researches:(1)I implement finite-difference simulation for acoustic wave equation in time domain by using optimal first-order stagger grid difference operator.It lays the foundation for reverse time migration.(2)I do some research about four imaging conditions of acoustic RTM,using composition strategy,combine energy focusing imaging condition with amplitude-preserving imaging condition,put forward optimal amplitude-preserving imaging condition,and apply it to model test.(3)Comparing four qP wave equations,analyze their advantages and disadvantages in theory,then states their characteristics using model tests,focus on the research of pure qP wave equation and pure qP wave equation with elliptic decomposed operator,and implement qP wave numerical simulation in complex TI media using pure qP wave equation with elliptic decomposed operator.(4)Implement qP-wave amplitude-preserving RTM in TI media using optimal amplitude-preserving imaging condition and pure qP wave equation with elliptic decomposed operator.