Method for distinguishing between total formation permeability and fracture permeability

摘要

A borehole logging tool traverses a subsurface formation known to contain naturally occurring fractures. Acoustic wave energy through the naturally fractured formations is measured by a pair of spaced-apart receivers in the logging tool. The ratio of the tube wave amplitudes measured by the pair of receivers identifies total formation permeability. The differences in the tube wave travel times measured by the pair of receivers identifies matrix permeability. The difference between total formation permeability and matrix permeability is attributable to the naturally occurring fractures in the formation.