GNGTS 2015 - Atti del 34° Convegno Nazionale

24 GNGTS 2015 S essione 3.1 Fig. 2 – Results of the synthetic inversion based on actual well-log measurements. a) The synthetic CMP, P-impedance, S-impedance and density are represented from left to right. For impedances and density the x-axes are represented with the same scale to better illustrate the increase of uncertainty that occurs passing from the Ip, to the Is and to the density estimates. In blue are represented the true elastic properties, in red the maximum a posteriori (MAP) solution, whereas the grey curves show Monte Carlo samples form the posterior probability distribution. The green arrows indicate the target gas-sand that generates a class III AVA anomaly in the synthetic seismogram. b) and c) Results of the petrophysical inversion that is the posterior conditional probability p(R|d obs ) (see Eq. 11). The water saturation, porosity and shaliness are represented from left to right, respectively. b) Results obtained applying the theoretical, non-linear, rock-physics model. c) Results obtained with the empirical, linear, rock-physics model.