Abstract：In conventional PP-PS wave inversion,time-travel single model is used to calculate the ratio of compress wave velocity and shear wave velocity(γ) in order to match compress wave and shear wave.This may cause serious error in complex structures and rough horizontal lithology variation.And conventional PP-PS wave inversion induced to inaccurate inversion due to the assumption of γ=2.This paper proposes a new method for prediction of fluid and lithology Using time-travel and amplitude energy to calculate dual γ models,this method obtain better matches of PP and PS waves.Then compress wave velocity,shear wave velocity and density and poisson ratio are inversed with three independence parameters named compress wave intercept,gradient and shear wave gradient.Simulated annealing provides a global optimization in inversion in order to avoid local extremum.This method gets a total forecasting coincidence rate above 80% in Sulige Gas field.
