Abstract:In cross-hole seismic data acquisition on Ken-71 block of Shengli Oilfield, the radiation energy of piezocrystal used for vibroseis mainly concentrated into horizontal direction, leading seismic reflections to have both normal reflections less than critical angle and wide-angle reflections greater than critical angle. In order to remove the influence of these wide-angle reflections on imaging of up-going reflections, the paper uses VSP-CDP approach to map the reflections from Z-T domain to Z-X domain; then sorts and forms CDP angle gathers according to incident angles on CDP gathers; and again computes the size of critical angle based on Snell law; finally, defines the angle range of stack imaging by reference to angle gathers of real data. The maximum critical angle in the region is 70°. The approach presented in the paper can overcome the influence of wide-angle reflections on imaging.