A Comparison of the Fluid Factor With λ And μ In AVO Analysis

Smith and Gidlow (1987) introduced the fluid factor in amplitude versus offset (AVO) analysis. It was designed to be a direct hydrocarbon indicator. Goodway et al. (1997) suggested that Lamé’s elastic parameters ? and µ, and their products with density, could be useful tools in AVO analysis. They suggested in particular that ?, or its product with density, ??, can be a direct hydrocarbon indicator. Gray et al. (1999) gave a method of estimating these parameters more directly, as does Chen (1999). Castagna and Smith (1994) presented a set of 25 worldwide measurements of P- and S-wave velocities and densities in associated shales, brine-saturated sands and gas-saturated sands and compared various commonly used AVO parameters. They concluded that the indicator Rp - Rs (the difference between P- and S-wave reflectivities) satisfy the conditions desirable for a hydrocarbon indicator.