GNGTS 2015 - Atti del 34° Convegno Nazionale

16 GNGTS 2015 S essione 3.1 computed from the actual well-log data. A slightly lower match characterizes the SR and the GA estimates and, particularly, the TRPM results. The actual benefits and drawbacks of each method can be seen in Fig. 3. In Figs. 3a, 3b, 3c and 3d we show a graphical representation of the rock-physics models previously derived. SR, NN, TRPM and GA outcomes are depicted from Figs. 3a to 3d, respectively. For the lack of space, we restrict our attention to the Vs parameter and to the porosity-shaliness plane only. The great similarity between the SR and the GA results can be observed by comparing Figs. Fig. 2 – Rock-physic templates showing the influence of each petrophysical parameter on the P-impedance (Ip) and S-impedance (Is). Water saturation (Sw), porosity (φ) and shale content (Sh) are represented from left to right. Part (a) refers to the actual well-log data, whereas parts (b), (c), (d) and (e) refer to the elastic properties predicted by the SR, NN, TRPM and GA methods, respectively. In part a) the hydrocarbon trend is indicated by the black arrow.