Interface Waves along Fractures in Anisotropic Media

摘要

The detection of fractures in an anisotropic medium is complicated by discrete modes that are guided or confined by layers, as well as by fractures, and that travel with velocities close (~92%) to the shear wave velocity. For instance, fractures can "mask" the presence of textural anisotropy in a rock, and can change the apparent shear wave velocity anisotropy. In this study, we examine the effect of fracture interface waves on the interpretation of shear wave velocities for two orthogonal polarizations propagating through a layered medium with fractures. These experimental results demonstrate that competing textural and structural properties can affect the interpretati?n of rock properties from seismic data. Interpretation in the presence of fractures in isotropic or anisotropic media can be unambiguously interpreted if measurements are made as a function of stress, which eliminates many fracture-generated discrete modes.