Super Wide-angle Propagator In The Local Cosine Domain

With the development of the oil and gas industry,the technology and theory of exploration itself has been developing.One of the most important project of sesmic exploration technology is to calculate accurate wavefield in complex media,with high calculation efficiency.This requires for an accurate and efficient migration method.In this paper,we will propose the Superwide-angle Propagator in Local Angle Domain,based on the traditional Generalized Screen Propator and Superwide-angle Propagator,and optimize the accuracy and efficiency of traditional migration method.In this paper,chapter one introduces the research background and basic theory of sesmic migration,and different types of migration method.We state the theory of wave equation migration,and introduce two solving methods,whihc are intergral soulution and differential solution.Chapter two introduce the one-way migration,which is to calcluate the wavefield at each screen and apply the image condition,by differential approximation.We analyze different kinds of one-way propagator and the image con-dition,and explain how to implement it with coding program.Chapeter three shows the disadvantage of the calculation accuracy of one-way propagator,and gives a solution method,which is Superwide-angle Propagator.The core theory of Superwide-angle Proapgator is to calculate two wavefield with orthogonal propagation direction,and ap-ply weighted summation to gain the final wavefield.Besides this,we also give some detail of implement Superwide-angle Propagator in program.At the bases of Chapter two and Chapter three,chapter four proposes the Superwide-angle propagator in Angle Domain,to solve the problem of the inthat the traditional Superwide-angle Propagator can not gain credible propagation angle.By importing Local Cosin Domain as the angle domain,the weighting of wavefield is moved from space domain to angle domain,to achieve a more accurate final result.Then,we shows the result of pre-stack migration with BP 2D model,which indicate that compared with traditional one-way proagator and traditional Superwide-Angle Propagator,the Superwide-angle propagator in Angle Domain can model wavefield with large propagation angle more accurately,and deal with the media with large horizontal velocity inhomogeneity.