Abstract:In order to more accurate petrophysical parameters data volume and reduce the accumulation effects of computed errors, the people want to directly pick up petrophysical parameters by some approach. Using Connolly elastic impedance (EI) formula to carry out inversion only directly yields the information of P-, S-waves velocities and density, and again yields corresponding elastic parameters by computation. The dimension of elastic impedance in different angles is non-uniform. In view of the shortage of Connolly approach and representing Zoeppritz's equation as the reflectivity being the function of shear modulus μ, Lame coefficient λ and density ρ by Gray approximation, the paper presented a new elastic wave impedance inversion formula based on Gray's AVO approximate equation, standardized the formula in order to uniform the dimension among the elastic wave impedances in different angles. The inversion was carried out for practical seismic data in A area by standardized elastic wave impedance inversion formula in the paper, shear modulus μ and Lame coefficient λ can be directly picked up from inverted elastic impedance data volume, which showed using the approach presented in the paper to pick up elastic parameters is more robust and accurate.