Predicting the transport properties of fractured rocks from seismic information: numerical experiments

The hydraulic properties including porosity and permeability of fractured rock masses are estimated from seismic velocities derived from controlled numerical experiments. Models of fractured media are developed to represent fractures embedded in an otherwise intact rock. Fracture porosity and permeability are computed using a hydraulic model that accounts for fracture length, aperture and orientation. Seismic attributes are used as a guide to detect the onset of reflections From the fractured medium. Seismic velocities of the fractured layers are computed from the transit times of seismic waves propagating through the layer. The study shows that the velocity ratio between the fractured and the intact rock correlates with the hydraulic properties. Low velocity ratios are associated with high fracture porosity and permeability. Empirical least-squares regression relationships are developed to describe the correlations for practical use. (C) 2000 Elsevier Science B.V. All rights reserved.