An improved LTI algorithm for multiphase raytracing in undulating surface model

Abstract Based on the linear traveltime interpolation (LTI) algorithm, we propose an improved LTI (referred as ILTI) algorithm for multiphase seismic ray tracing, which uses a velocity node in model parameterization and introduces secondary nodes between adjacent nodes. To better fit undulating surface model, irregular is used near interface, regular are still region far away from interface. We derive iterative fixed-point formula calculating traveltime. By combining multistage computational technology wavefront narrowband expansion technology, proposed ILTI can efficiently trace raypath compute corresponding field. Through comparison analysis with traditional its accuracy be highlighted by at least one order of magnitude. Compared popular fast marching method (FMM) shortest-path (ISPM) algorithms, it also has advantages terms efficiency. Numerical simulations Marmousi show that suitable tracking rays complex model.