Numerical Simulation Of 3D Seismic Wavefield Based On Traveltime Bilinear Interpolation

The increasing complexity of geological targets puts forward higher requirements on geophysical exploration technology,which has promoted seismic exploration into a highprecision and high-resolution stage.Wide-azimuth(omnidirectional)and broadband 3D seismic exploration has become the way to obtain fine underground structure imaging.The main methods,especially in offshore oil and gas exploration,are more widely used.Therefore,the study of numerical simulation and propagation laws of seismic waves in three-dimensional media has become an indispensable method for understanding seismic wave fields,testing data processing,and realizing seismic tomography.The ray tracing research on the 3D seismic model has important practical significance for the optimization design of data acquisition and observation system,seismic illumination analysis,tomography,seismic inversion,etc.In the travel time linear interpolation(LTI)ray tracing process,there are two core processes including forward processing to calculate the minimum travel time and backward processing to reverse tracing the ray path.Many scholars have studied these two processes,greatly improving the computational efficiency The calculation accuracy enhances the calculation of the reverse ray,making the linear interpolation method a ray tracing method with unique advantages.Bilinear interpolation during travel is a form in which two-dimensional LTI ray tracing is extended to three-dimensional seismic models,and it is an important method to realize three-dimensional seismic ray tracing.Compared with the two-dimensional LTI method,the bilinear interpolation ray tracing is more complicated in local travel time calculation,tracking strategy and implementation method.This paper focuses on the numerical simulation method of 3D ray tracing seismic wave field based on travel time bilinear interpolation,and realizes the travel time calculation and ray path tracing of 3D seismic model.First,improve the two-dimensional LTI cyclic scanning method in the forward processing process,and propose an omni-directional cyclic scanning method adapted to the three-dimensional model,which more comprehensively considers the problem of ray back propagation,and ensures the accuracy of the minimum travel time calculation in the forward processing process Sex.Secondly,on the basis of the threedimensional LTI calculation of the first arrival wave information,the travel time bilinear interpolation method is further combined with the partitioned multi-step calculation strategy to realize the reflected longitudinal wave,converted wave and multiple wave arrival of the threedimensional medium.Tracking calculations.Finally,through the calculation and ray path tracing of the first arrival wave,reflected wave,converted wave and multiple wave travel time of different three-dimensional theoretical models,the reliability and correctness of this method are verified.