Abstract: Based on the measured data of core porosity and the well logging acoustictravel time, the target plates of porosity and acoustic travel time in study area are presented, and determining the cut?off of porosity is 11%, that of acoustic travel travel time is 220 μs/m for the effective glutenite reservoirs. The study from sensitivity analysis of rock elastic parameters that S?wave velocity can be well used to distinguish the sandstone and mudstone in the first member of Dainan formation in Gaoyou sag, the density can be used to distinguish oil layer,water layer and dry layer. Using the prestack S?wave velocity inversion to predict the target zone’s lithology, the prestack P?wave velocity inversion to predict the effective reservoir’s porosity, and then making evaluation of rationality of those predicted results of net pay thickness and porosity, by which the effective reservoir’s net pay thickness and petrophysical property distribution regularities in the study area can be finally obtained