Abstract:At present,the important parameters for evaluating the sealing ability of covering bed involve displacement pressure,porosity,permeability,density,mid-value semidiameter of pore,specific surface area and so on.Especially,displacement pressure is the most important one.Real data analysis leads to the conclusion:1)displacement pressure increases with the decrease of porosity,permeability and midvalue semidiameter of pore,but with the increase of density and specific surface area;2)acoustic velocity can be described by using porosity(Δt=Aψ+B),and the porosity is closely related to density;and 3)properly-corrected seismic interval velocity can be used as substitute for acoustic wave velocity.Consequently,people may get the relation between seismic interval velocity and displacement pressure.Then displacement pressure in an area may be derived from the relation.