Abstract：Common DIVA methods (differential interformational velocity analysis meth-ods) generally take interval velocity of one lithology as background velocity,thus resulting in lithologic multiple solution. Therefore they are not suitabIe to predic-tion of complicated lithology series. Double-critical DIVA method is put forward to do detailed lithology division- With the use of two critical conditions,this method not only determines whether a formation is bias-arenaceous or bias-argillaceous but also discovers the formation in which seismic velocity is superhigh or superlow. It is illustrated that this method predicts more reliable lithology than others do.
