f Natural Fracture Characterization Using P-Wave Reflection and Multicomponent VSP

As part of a Department of Energy study, a 9C VSP and two crossing lines totaling ten miles of 9C surface seismic were acquired to study the fractured gas reservoir in the upper Green River formation at the Bluebell-Altamont field, Utah. An azimuth-dependent amplitude variation with offset (AVO) anomaly was observed in the P-wave reflection seismic, attributed to the anisotropy caused by the presence of gas-filled vertical oriented fractures. The presence of seismic anisotropy was substantiated by the 9-component (9C) VSP.