Poisson Impedance : A promising tool for determination of sand quality

We demonstrate the separation of sand stone reservoir from shale where gas sand and shale have almost similar P-, S-impedance contrast using Poisson Impedance (PI). The correlation coefficients between PI curve (with different c values) versus Gamma ray and Water saturation curve are computed. The c value corresponding to maximum correlation coefficient for GR is used to compute another attribute namely lithology impedance (LI). Similarly, fluid impedance (FI) is computed using c value that corresponds to maximum correlation coefficient for Sw curve. The cross-plot between LI and GR shows the advantages of LI in distinguishing sandstone from shale. Fluid content is predicted using the linear relationship exhibited on the cross-plot of FI versus Sw.