The Potential of Estimating Fracture Sizes from the Frequency Dependence of Anisotropy

C-24 THE POTENTIAL OF ESTIMATING FRACTURE SIZES FROM THE FREQUENCY DEPENDENCE OF ANISOTROPY Summary 1 Frequency-dependent anisotropy has been observed in seismic data and it can be explained by fluid flow in fractured porous rock. In this study we use a new equivalent medium theory that considers fluid movement due to a squirt-flow mechanism at two scales: the grain scale where the pore space consists of micro-cracks and equant matrix porosity and formation-scale fractures. The theory models velocity dispersion and frequency dependence of anisotropy with the fracture length being one of the key parameters. The model is first tested and