  The high accuracy on inferrring of rocks properties, such as permeability
($k$), is a very useful study in the analysis of wells. This has led to
development and use of empirical equations like Tixier, Timur, among others. In
order to improve the inference of permeability we used a hybrid Neuro-Fuzzy
System (NFS). The NFS allowed us to infer permeability of well, from data of
porosity ($\phi$) and water saturation ($Sw$). The work was performed with data
from wells VCL-1021 (P21) and VCL-950 (P50), Block III, Maracaibo Lake,
Venezuela. We evaluated the NFS equations ($k_{P50,i}(\phi_i,Sw_i)$) with
neighboring well data ($P21$), in order to verify the validity of the equations
in the area. We have used ANFIS in MatLab.
