Patent ID: 8682587

Claim:
A method of determining the permeability of a downhole earth formation executed by a computing processor, comprising the steps of: generating an acoustic signal at a first point in a borehole; detecting, as an acoustic response at a second point in the borehole, variations in pressure resulting from the acoustic signal; detecting as an electric response at the second point in the borehole, variations in an electric field resulting from the acoustic signal; and determining, using the processor, the permeability of the earth formation using the detected acoustic and electric responses by solving a Biot equation and an expression for a streaming potential given in terms of the fluid and solid displacement to yield an expected pressure waveform and an expected electrokinetic waveform, each based on estimated earth formation properties, and using the processor for comparing the acoustic response and the electric response with each of the expected pressure and electrokinetic waveforms to determine an actual permeability of the downhole earth formation.