Attenuation of Seismic P-Waves in Multilayered Gas Hydrate-Bearing Sediments

We present an analysis of a time lapse walkaround, multilevel vertical seismic profile (VSP) data set from a carbonate field in Oman which has a long history of steam injection and production. The aim of this study is to compare changes in traveltime and attenuation variations in response to fracture orientation. The method used for calculating the attenuation factor Q, is based on the instantaneous frequency technique. Velocities and attenuation are sensitive to the fractures, presenting shorter travel times and lower attenuation in the direction of the fracture plane. We show through the case study the effectiveness of the method and the potential of azimuthal attenuation and travel-time studies of P-waves for fracture characterization.