10 Facts About Seismic migration

Seismic migration is the process by which seismic events are geometrically re-located in either space or time to the location the event occurred in the subsurface rather than the location that it was recorded at the surface, thereby creating a more accurate image of the subsurface.

Need for migration has been understood since the beginnings of seismic exploration and the very first seismic reflection data from 1921 were migrated.

Computational Seismic migration algorithms have been around for many years but they have only entered wide usage in the past 20 years because they are extremely resource-intensive.

Seismic migration waves are elastic waves that propagate through the Earth with a finite velocity, governed by the elastic properties of the rock in which they are travelling.

Zero-offset data is important to a geophysicist because the Seismic migration operation is much simpler, and can be represented by spherical surfaces.

The significant advantage to this Seismic migration method is that it can be successfully used in areas with lateral velocity variations, which tend to be the areas that are most interesting to petroleum geologists.

Goal of migration is to ultimately increase spatial resolution and one of the basic assumptions made about the seismic data is that it only shows primary reflections and all noise has been removed.

Graphical Seismic migration assumes a constant velocity world and zero-offset data, in which a geophysicist draws spheres or circles from the receiver to the event location for all events.

Depth Seismic migration begins with time data converted to depth data by a spatial geological velocity profile.

Post-stack migration begins with seismic data which has already been stacked, and thus already lost valuable velocity analysis information.