Poroelasticity and Rock Physics Templates for Faster and More Accurate EEI/EPI Inversion

In this talk, Brian Russell (Vice President, GeoSoftware) will propose a link between rock physics templates (RPTs) and the theory of poroelasticity. The most well-known RPT is a cross-plot of V_P/V_S ratio vs P-impedance (I_P), on which both facies and rock physics models can be superimposed. A second common RPT is a cross-plot of vs , using the Lambda-Mu-Rho, or LMR, approach. Brian will first show how curves of constant LMR values can be superimposed onto a V_P/V_S versus I_P cross-plot. We will then discuss the K-Mu-Rho, or KMR, approach and show how curves of constant KMR values can be superimposed onto a V_P/V_S versus I_P cross-plot. Brian will then generalize the LMR and KMR approaches using poroelasticity theory, proposing the FMR, or Fluid-Mu-Rho approach. This introduces a new fitting parameter, the dry rock V_P/V_S ratio, or d, which allows us to superimpose realistic rock trends on V_P/V_S versus I_P cross-plots. Finally, we will show how the optimization of the dry rock V_P/V_S ratio parameter d allows us to produce more accurate poroelastic AVO, poroelastic pre-stack inversion, and Extended Poroelastic Impedance (EPI) inversion results.

Presenter: Brian Russell, Vice President, GeoSoftware