Abstract

Presence of obliquely dipping fractures in an otherwise isotropic medium reduces the symmetry of the elastic coefficient tensor, with the resulting medium behaving as transversely isotropic with a tilted axis of symmetry. The amplitude variation with offset and azimuth (AVOA) response exhibits sinusoidal variation with respect to the azimuth with peak/ trough oriented along the fracture strike direction, except for near vertical incidences. We have developed a scheme to estimate the dip of arbitrarily dipping fractures from the analysis of AVO along and perpendicular to the strike of the dipping fractures. Results from simulated examples show that the present method yields satisfactory values of the dip estimates for dilute fractures either fully or partially saturated with gas