Abstract:There exist continental sandstone and mudstone formations in DZW area.AVO technique can be well used to predict gas reservoir in this area because of both the simple geological structures and the stable formations.First of all,single-interface AVO forward modeling based on Sh-uey's equation is made to obtain a series of reflection coefficient ver-sus incident angle under different parameter conditions.If Poisson's ratio difference between sandstone arid overlying mudstone is small.the reflection coefficient of mater-saturated sandstone increases slightly with the enlargement of incident angle while the reflection coefficient of gas-saturated sandstone inereasesgreatly with the broadening of inci-dent angle.In AVO data processing,we must do our best to remove the influ-ence of various surface factors.on reflection amplitude,and to obtain correct NMO correction velocity.It is necessary,hence,to conduct surface-consistent deconvolution,surface-consiste nt residual statics,surface-consistent amplitude processing and secondary velocity analysis.Furthermore,angular scanning is used to determine angle range for AVO analysis and to form stacked angular-trace gather.Gas reservoir distribution around well No.W21 was mapped and three possible gas reservoir areas were predicted by analysing angular-trace gathers·and other materials.