The Research Of Seismic Controlled Beam Migration Method By Multi-Strategy

In the exploration and development of oil and gas source,seismic data always plays a significant role.The high-quality seismic profile not only can be used for the interpretation of geological layers and faults.Digital processing for seismic data is a bridge between the acquired field data and the final interpretation results,and the revolution of its theory and techniques marks the overall progress and development of seismic exploration industry.One of the critical technologies,migration processing,is to map the common-shot or common-offset data to imaging domain according to seismic propagation law,which is after the processing of removing direct wave,static,denoising,deconvolution,compensation,nmo,velocity spectrum,migration and other modues.This can help us restore the spatial shapes and distribution patterns of geological structures,which reflect the thousand meters of underground geometric information for the oil and gas reservoir prediction.Recently,the commonly used migration method in practical production is Kirchhoff method,but in order to solve this defect of imaging by caustics,shadow zones,the Gaussian beam migration comes into being,can be viewed as a combination of wave equation migration and ray-based methods,which not only retains the high efficiency and flexibility of ray-based methods,but also can define the complex fault blocks and high steep structures and has a comparative imaging accuracy to wave equation migration.It can be used for complex fault block,high and steep structure.The aiming at the fact that there is some background noise and random noise in the actual data,the effective signal and the interference noise can not be effectively distinguished in the taup-p domain.Therefore,the research of seismic Controlled beam migration method by Multi-strategy are proposed.The research content mainly includes the following aspects:(1)Based on the wave equation migration,the asymptotic ray theory solution into the wave field is obtained,beginning from the zero-order Ray theory,we derived the kinematic and dynamic ray tracing equations of paraxial ray theory,and then used its complex form to construct Gaussian beam and discussed the features of its beam width,wave front curve and central ray amplitude;(2)Due to the difference between the effective energy and the interference noise on the taup-p coordinate graph,the threshold of controlled beam expression is derived,and the threshold of controlled beam migration imaging method is developed.(3)On account of the taup-p domain coherence control for effective energy constraints,derived the formula of the coherent of controlled beam,developed based on coherent of controlled beam migration imaging method;(4)In view of the computational efficiency and adaptability in the time domain by Gaussian beam,which can be applied to the irregular data on the land and sea,the imaging formula of the time domain by Gaussian beam is deduced,and the Hanning window is added to filter,therefore,the filtering window of controlled beam migration in the time domain is implemented.On the basis of the programming algorithm,the above methods are applied to the processing of the model test and the real data,which verify the correctness and adaptability of the method.