Abstract：The ordinary 3-D seismic data migration is often finished by two-step approach. However,correct migration of 3-D seismic data can hardly be achieved because crossline and inline are usually not along true dip direction of geological body.Unfortunately,true 3-D seismic migration has not found its wide application because of big internal storage need and heavy computation. Pseudo-true 3-D projective migration is thus advanced,and it includes following essential steps:·Obtain a series of radial sections by making Radon projection of time slices of stacked 3-D data volume.·Conduct forward and inversive Radon transforms of each radial section to produce radial migration section.·Achieve a true=dip migration by doing Radon inverse projection of time slice.The method offers good migration of 3-D data volume,improved signal/noise ratio of seismic section,desirable continuity of seismic events,satisfactory images of various geological structures. What is more,it needs as much internal storage and computations as two-step approach does;and it brings the seismic resolution which is equivalent to that other methods creat. It has been shown in practice that this method is an ef1ective 3-D poststack migration technique.
