The Least-squares Reverse-time Migration

Migration imaging technique is one of the important parts of seismic exploration,and the migration's result is directly related to the success or failure of seismic exploration.Migration imaging is the process to get the imaging profile of reflection coefficient of the underground medium,through processing seismic records with known underground medium model.Nowadays,the exploration targets are getting more and more complex,and the requirement of migration imaging technology is more and more high.Reverse time migration is the technique of migration imaging for pre-stack data with high precision,using the full wave equation to carry out the wave field continuation,which can be suitable for any change of speed,so it is well applied for complex structures.But the operator of inverse time migration does not equal the inverse one of seismic wave propagation,so the result of imaging does not equal reflection coefficient of underground medium which needs further processing,that is the category of least-squares inverse-time migration.Least-squares inverse-time migration is a better migration method,because its operator is the generalized inverse operator of wave propagation forward,and the result obtained is more close to the reflection coefficient of the underground medium.This paper studies the phenomenon of forward propagation of wave equation and inverse-time imaging,and the least-squares inverse-time migration based on the Born approximation.By testing the model data,comparing with the results of least-squares inverse-time migration and conventional inverse-time migration,it verifies the excellent performance of the least-squares inverse-time migration using GPU high performance computing technology to accelerate the above processes in terms of computational efficiency.