This paper presents a method to estimate permeability using time-lapse log data. The reservoir permeability values are also obtained by history matching production data and analyzing core data. These permeability values are in agreement with the estimates derived from logs. When a well is drilled, mud filtrate invades the formation around the borehole. The volume of mud-filtrate invasion is related to time, formation permeability, and other wellbore and formation parameters. As mud-filtrate invasion progresses, unique saturation profiles and, thus, unique profiles of resistivity and water saturation, are created in the formation surrounding the borehole. Therefore, the data from well fogs change with time. By observing and analyzing the changes in log data vs. time, one can estimate formation permeability.