Abstract:A fast ray-tracing algorithm is recommended here. The algoritram is characterized by special model dissection and simple raypath searching. A series of vertical parallel lines dissect the layered model to form a special grid, where the crosspoints made by each interface and all parallel lines are the knots which can approximately represent the interface. Assuming that rays go through the knots, we can use Fermat principle and simple three-point comparison method to iteratively derive reasonable raypaths, from which we can calculate corresponding travel-times and then generate synthetic seismic records. This algorithm is simple in princple, fast for computation and versatile. It is applicable to varied complicated geological structures and many kinds of field layouts. Furthermore, it can be used to calculate synthetic record, travel time in travel time inversion, and image time in migration processing. Some computation results are given to show the feasibility of the algorithm, and the accuracy of the model dissection.