Multiple removal based on detection and estimation of localized coherent signal

The removal of multiples without simultaneously distorting primaries is a difficult aspect of demultiple techniques. We present a new demultiple approach based on detecting and estimating localized coherent signals (multiples and primaries) on stacking velocity spectra. ne trajectories of localized coherent signals are determined from the velocity and zero-offset traveltime; amplitude variations with offset (AVO) are modeled from known AVO properties. We estimate primaries and multiples from stacking velocities by polynomial approximation of the amplitude along the hyperbolic path. This procedure lets us predict multiples on near-offsets using the multiples on other offsets. To further preserve the amplitude of the rebuilt primaries, stronger multiples, which are detected according to a multiple-to-primary energy ratio, are estimated and subtracted from the seismic data before estimating the primaries. Because the estimation of primaries and multiples is done locally in the time-space domain, our method is efficient. Comparisons are made between our method and conventional Radon filters. The results of both synthetic and field seismic data show that our method is very promising in practical applications because it can suppress the multiples efficiently while preserving the primary amplitudes well.