The Research Of Prestack Reverse Time Migration Method Based On Poynting Vector

In the field of seismic exploration,seismic migration imaging is an important technique for accurately obtaining the image of underground structure,and the reverse time migration(RTM)technique shows superior performance in improving the quality of complex medium imaging compared with other migration techniques.RTM is not restricted by the dip angle of the formation.It has better amplitude fidelity and high imaging accuracy.Therefore,it has attracted the attention of the academic community.But at the same time,it is also limited by its own shortcomings,including large amount of computation,large storage capacity,low frequency noise interference and so on.In order to solve the problem of large storage,this paper compares several different storage strategies.After comparison and verification,it is found that the efficient boundary storage strategy can effectively solve the problem of storage capacity at the expense of small amount of computation.The Marmousi model is applied to the computation and simulation,which proves that the application of this method in RTM is very significant.There are a lot of low frequency noise interference in RTM.Aiming at the problem of low frequency noise,this paper develops a study if low frequency noise is suppressed.By comparing and analyzing several kinds of denoising methods,the advantages and disadvantages of all kinds of denoising methods are summarized.The Poynting vector can describe the characteristics of the propagation direction of the wave field and the agreement with the first order stress velocity wave equation.The wave field decomposition denoising method and the angle attenuation factor denoising method are realized.The two methods are applied in the imaging conditions to obtain the new wave field decomposition angle to screen the cross correlation imaging conditions.A simple model and a Marmousi model are used to simulate the numerical experiments.The final results show that the new imaging conditions can better suppress low frequency noise and improve the imaging results of RTM.The Poynting vector can describe the direction of wave field propagation.Using the feature of Poynting vector,the reflection angle information can be obtained by using the vector angle formula,and the extraction of common imaging point set in diagonal domain is realized.In the process of extracting corner sets,the extra amount of calculation and storage is very small,and the effective and RTM steps are combined.The principle is simple and easy to be realized.Experiments on simple models and Marmousi models are carried out,and the result of corner gathers is successfully obtained,which proves the effectiveness of the method.