时限时移相关法叠前逆时成像条件及其应用

Time-limited time-shift correlation pre-stack reverse-time imaging condition and its application.

(中国石油天然气股份有限公司大庆油田有限责任公司勘探开发研究院，黑龙江大庆163712)

Chen Keyang,Exploration and Development Research Institute,Daqing Oilfield Company Limited,Daqing 163712;China

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。

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.