Intrinsic and apparent seismic attenuation in VSP data

Abstract

This paper investigates transmission loss contributions to seismic attenuation in VSP data from the Ross Lake heavyoil field, Saskatchewan. We compensate for transmission losses when estimating seismic attenuation (Q) by the analytic signal method. Major Q-estimate changes are not observed when compared to results obtained from the analytical signal method without this compensation. 1D scattering is not a major contributor to apparent attenuation. 2D scattering shows offset dependent stratigraphic "attenuation/amplification". Stratigraphic "amplification" is one possible explanation for the peaking of shallow depth Q-estimates from actual VSP data.