Abstract: The invention relates to the methods for determining the permeability of a geological formation saturated with a liquid and provides for a method, a system and a logging tool for estimating permeability. The method comprises exciting a formation with acoustic energy pulses propagating into the formation, measuring the acoustic response signals produced by the acoustic exciting and the electromagnetic signals produced by said acoustic energy pulses within the formation and separating components from said measured acoustic response signals and said measured electromagnetic signals representing Stoneley waves propagating through the formation. The acoustic response signals and electromagnetic signals representing Stoneley waves propagating through the formation are synthesized. The separated acoustic response signal and electromagnetic signal components and the synthesized Stoneley wave signals are compared.