Study On The Parameters Optimization And Velocity Model Smoothing Of Gaussian Beam Migration

Gaussian beam prestack depth migration rose in the 1990 s.As an important seismic exploration method,it plays an important role in the process of oil and gas exploration.However,it is still difficult to consider both imaging accuracy and computational efficiency in conventional Gaussian beam prestack migration.Aiming at the problem of imaging accuracy and computational efficiency of Gaussian beam migration,the parameter optimization and velocity model smoothing of Gaussian beam migration method are studied,and the existing Gaussian beam migration methods are further optimized.Firstly,this paper deduces the Gaussian beam prestack depth migration imaging method,analyzes and discusses the imaging effect in complex media,and uses different velocity models for model trial calculation to prove the rationality of this method.Secondly,the parameters affecting the imaging accuracy and efficiency of Gaussian beam migration are analyzed.Aiming at the influence of various parameters of Gaussian beam migration on migration imaging,the optimal parameter combination of Gaussian beam migration is obtained by optimizing the parameter selection.Then,the influence of smoothing strategy on migration imaging accuracy is analyzed.In view of the influence of velocity model smoothing on migration imaging accuracy,the convolution smoothing operator is used to smooth the velocity model,and different smoothing strategies are numerically simulated to obtain the optimal velocity model smoothing strategy.Finally,the defects of conventional Gaussian beam offset are analyzed.Aiming at the problem of insufficient imaging accuracy of conventional Gaussian beam migration at the far end of the ray,a Gaussian beam migration method based on non smooth ray travel time is proposed,and the feasibility of the method is verified by model trial calculation.Through the above research,we draw the following conclusions:(1)the core parameters of Gaussian beam migration greatly affect the quality and efficiency of migration imaging.Reasonable selection of migration parameters can give consideration to both imaging quality and computational efficiency.(2)Using a reasonable smoothing strategy to smooth the velocity model can greatly improve the imaging quality of migration imaging.(3)Gaussian beam migration based on non smooth ray travel time can effectively improve the imaging accuracy of Gaussian beam migration.