Hybrid gather ground-roll suppression

Abstract

This invention relates to the general subject of seismic exploration and, in particular, to seismic processing and methods for attenuating ground roll in land and ocean bottom seismic surveys. According to a first aspect of the instant invention, there is provided a method of attenuating non-primary reflection events such as ground roll in an unstacked gather. In the preferred embodiment, the collected seismic data will be analyzed to determine the approximate velocity at which the ground roll appears to travel through the section. As a next step, a single-velocity migration is performed on the seismic data at the selected velocity. Those seismic events that are moved by the migration past an “attenuation line” on the section are intentionally discarded or attenuated. Finally, a reverse single velocity migration is performed which places the reflectors—minus those events such as ground roll that have been attenuated—back at their original unmigrated times.