f Fracture detection using reverse vertical seismic profiles and cross-hole surveys

Previous observations have suggested that the effects of fractured-related seismic anisotropy is observabIe, particularly in vertical seismic profiles (VSPs) (Crampin et al. 1986; Johnston 1986, and among many others). Fractures can be a significant feature of hydrocarbon reserviors where their presence (either natural or .induced) may increase the productive capacity. Many reserviors with a low matrix permeability would not be commercially attractive without a natural or induced fracture system. Fractures at the shallow depths are also important for the fluid flow in engineering and hydrological applications.