Abstract：The calculation of primary and various multiple reflections in downhole-source SVSP data favours the identification and study of these reflections in real VSP data.Wyatt[1]method for calculating.primary and multiple reflections is improved so that it is applicable to anysource-depth case,The improved method finishes the calculation in twosteps:(1)calculating the primary and multiple reflections producedrespectively by source-generated upgoing and downgoing wavelets,and(2)stacking the corresponding reflections to obtain the primary andmultiple reflections in downhole-source SVSP data,Theoretical calcula-tion proves this method feasible.
