بررسي و مقايسه كوچ هاي زماني قبل و پس از برانبارش

A comparison of post-and pre-stack time migrations

Migration is a process that reconstructs an image of the earthʹs reflecting structure from elastic wavefield energy recorded at the surface in seismic traces. In seismic imaging, conventional processing is concentrates on producing a stacked section from common mid point gathers and is followed by a poststack migration, while in a prestack migration, first the events are migrated one by one, then those are stacked and the energy the common reflection point gathers goes to the surface of the earth. In this paper the effects of both post-and pre-stack time migration methods are compared by use of the Kirchhoff summation method on a seismic line in the central Iran area. The method of data collection is offend and the foldage is 48. The source of energy in acquisition is dynamite. The work is implemented by using PROMAX 6.0 software on ULTRA SUN system.The results are as follows: Continuity of reflectors will be improved after prestack migration. Velocity analysis after prestack migration is improved and provides a better harmony of the velocities. Because of the increasing of the reflectorʹs amplitudes continuity, some geology structures appeared after prestack migration.