Q-estimation from uncorrelated Vibroseis VSP model data

Arnim B. Haase

A known method for velocity dispersion estimation and Q-factor calculation from uncorrelated Vibroseis records is investigated. In this method pilot sweeps are partitioned into time segments by successive windowing, each with a different central frequency. These segments are cross-correlated with the entire received sweep at all VSP-stations allowing the automatic picking of frequency and depth dependent travel times and the calculation of velocity dispersion. The method is tested with two synthetic zero-offset VSPs. Q-factors can be recovered fairly accurately away from the near-field in the special case of a homogeneous earth. Velocity dispersion and the Q-factor derived from it are quite sensitive to stratigraphic effects.