【摘要】 地震波逆时偏移法是目前成像精度最高的成像技术。分析了相关法叠前逆时成像的基本原理,提出了时限时移相关法叠前逆时成像条件。运用高阶交错网格有限差分法,按照一定的观测方式合成了基于Marmousi模型的123个炮集记录,并应用时限时移相关法叠前逆时成像条件进行了叠前逆时深度偏移,将获得的剖面与反射系数深度剖面进行了对比。数值计算结果表明,应用时限时移相关法叠前逆时成像条件获得的偏移剖面准确反映了Marmousi模型中的各个地质反射界面及其反射系数的变化特征。与时空移相关法叠前逆时成像条件相比,时限时移相关法叠前逆时成像条件能够大大减少计算量和存储量,提高了计算效率。更多还原

【Abstract】 Seismic wave reverse-time migration is one of the methods with higher imaging accuracy.We analyzed the basic principles of the correlation pre-stack reverse-time migration,and presented time-limited time-shift correlation pre-stack reverse-time imaging condition.By using high-order staggered-grid finite-difference method and following a certain survey,123 shot gather records based on Marmousi model were generated.Then the time-limited time-shift correlation pre-stack reverse-time imaging condition was applied to carry out pre-stack reverse-time depth migration,and the obtained seismic profiles were compared to the reflection coefficient depth profile.The numerical computational result shows that the profile of time-limited time-shift pre-stack reverse-time imaging condition accurately reflects each geologic reflection interface and its variation characteristics of the reflection coefficient in the Marmousi model.Compared to space-time shift correlation pre-stack reverse time imaging condition,our imaging condition largely reduces computational and storage amount,and improves the computational efficiency.更多还原