f Fracture-related seismic velocity and attenuation anisotropy at the Conoco borehole test facility, Oklahoma

Shear-wave splitting and fracture-related seismic anisotropy have already been reported from numerous VSPs, crosshole and reverse VSP (RVSP) datasets at the Conoco Borehole Test Facility (CBTF) with an aim of investigating the use of seismic waves to map subsurface fracture systems (Queen & Rizer 1990; Liu et al . 1991). In this paper, we further analyse shear-wave data recorded from the multi-azimuthal reverse VSPs. Fracture-related seismic velocity and attenuation anisotropy can be clearly identified based on the analysis of amplitude and travel times. Our interpretations are supported by comparison with the theoretical prediction of velocity and attenuation variations in fractured media and by calculation of synthetic seismograms.