f Datuming and time migration

Before interpretation, data acquired over rough topography should be corrected to a horizontal reference surface or datum . This datuming is typically accomplished by statics and/or wave equation downwand continuation in depth. Common practice is to foren a stack to a smooth version of the actual surface (the floating datum) via stacks and then apply post-stack datuming . If the velocity of the neer surface is close to the subsurface velocity, static corrections can be inaccurate for dipping reflections and a wave equation method is needed .