Efficient one-pass 3-D time migration

摘要

An efficient one-pass 3-D time migration algorithm is introduced as an alternative to Ristow's splitting approach. This algorithm extends Black and Leong's k_y-separation approach with a time-dependent Stolt stretch operation called dilation. Migration using k_y dilation consists of a single pass over the 3-D data volume after k_y slices are formed with each k_y slice downward continued independently. A number of downward continuation algorithms based upon the 3-D wave equation may be used. Dilation accommodates any lateral variations in velocity before the 3-D data volume is decomposed into k_y slices via a Fourier transform. An inverse dilation operation is performed after the downward-continuation operation and after the data volume have been inverse Fourier transformed subsequently along the k_y direction. Migration using the k_y -dilation approach yields a one-pass 3-D time migration algorithm that is practical and efficient where the medium velocity is smoothly varying.