Extracting petrophysical parameters from elastic impedance

摘要

Definition of elastic impedance (EI) is a nonlinear formulation proposed by Connolly's (1999) , which is made linear in this paper to extract the petrophysical parameters, so that the linear relationship is built up among EI and P-velocity, S-velocity and density. Using EI data near wells as a constrained condition, according to their relationship it is easy to estimate the angle constants and regress the basic petrophysical parameters, such as P-velocity, S-velocity and density. And then, by introducing the relationship among petrophysical parameters the other parameters, such as Poisson Ratio, P-impedance, S-impedance, Lambda * Rho, Mu * Rho and Lambda/Mu and so on, can be computed. These parameters are more accurate than those acquired by AVO inversion in account for lithology and liquid property, and can easily verify one another.