Removal of frequency notches in marine seismic data acquired by a deeply towed source

Abstract

Summary We developed a processing method to separate and utilize long-period sea surface reflected waves by applying wavefield extrapolation processing. It would be possible to separate the sea surface reflection waves from the survey data with high accuracy using the pseudo sea surface reflection generated by downward wavefield extrapolation. In addition, it would also be possible to use the separated multiple to enhance the signal-to-noise ratio of the survey result by applying the upward wavefield extrapolation. We applied our method to the survey data obtained by the deep-towable marine seismic vibrator towed at 225 m depth to verify the effectiveness of our method. Our processing method could remove the effect of a long-period sea surface reflection, which has been a problem to realize a seismic survey with a deep-towed seismic source. In addition, our proposed method could use the decoupled reflection waves to enhance the signal strength by considering it as survey data from a mirrored source.