This thesis introduces new software to interactively construct multi-layer models and bedding sequences, populate layer-by-layer properties, and enable the fast simulation of nuclear logs. The method consists of modifying simultaneously layer thicknesses and properties to rapidly simulate the outcome (nuclear logs) for comparison to field logs. I include applications which appraise the numerical simulation of gamma-ray, density, compensated neutron, and photoelectric factor logs. An analogous application for sonic modeling is considered as well which uses a modified version of Wyllie’s slowness averaging equation. The procedure is tested for the case of vertical wells and horizontal layers. Examples of application include 6 synthetic and 5 field cases. Additionally, the software is implemented in combination with other formation-evaluation procedures to interpret resistivity and nuclear logs. Simulations of nuclear logs for synthetic models can be used to improve the assessment and interpretation of field data. Interactive modeling and simulation of nuclear logs provides a very good agreement with field logs with an average error of 3.9%. The order of logs to be matched as well as the data available are significant factors in the accuracy of the match. Numerical simulation and matching of field logs using fast modeling procedures is a reliable method to improve the inference of static and dynamic petrophysical properties of rock formations. / text