Stephan Gelinsky

US Patent:

57843333, Jul 21, 1998

Filed:

May 21, 1997

Appl. No.:

8/861263

Inventors:

Xiaoming Tang - Sugar Land TX
Stephan Gelinsky - Houston TX
Raghu K. Chunduru - Webster TX
Arthur C. H. Cheng - Houston TX

Assignee:

Western Atlas International, Inc. - Houston TX

International Classification:

G01V 140
E21B 4900

US Classification:

367 30

Abstract:

A method for determining the permeability of earth formations penetrated by a wellbore from acoustic signals measured by an acoustic wellbore logging instrument. The method includes separating components from the measured acoustic signals which represent Stoneley waves propagating through the earth formations. Signals representing Stoneley waves propagating through the same earth formations are synthesized. The separated acoustic signal components and the synthesized Stoneley wave signals are compared. The permeability is determined from differences between the synthesized Stoneley wave signals and the separated acoustic signal components. In a preferred embodiment, the step of calculating the permeability includes inversion processing a wave center frequency shift and a wave travel time delay with respect to the permeability of the earth formations.