Azimuthal anisotropy analysis to estimate the fracture orientation and the relative fracture density

Coal is an important source of energy, but releases a significant amount of carbon dioxide into the atmosphere. Consequently, developing efficient carbon capture and sequestration strategies to mitigate global warming is of great practical significance. The presence and orientation of fractures within a reservoir and its seal governs the long-term effectiveness of carbon dioxide storage. Fractures within a formation result from in-situ stress distributions and are characterized by an anisotropic behavior on the observed seismic responses. Wireline data provide information about factures at the well location, but away from the well one must rely on the seismic data. This work analyzed P-wave multiazimuth seismic data from a potential carbon sequestration site, located at the Rock Springs Uplift in Wyoming, USA. Using prestack waveform inversion, accurate azimuthal velocities were obtained for offset-to-angle transformation and to compute azimuthal angle gathers. These angle gathers were then stacked for each azimuth and analyzed for azimuthal anisotropy to estimate the fracture orientation and relative fracture density. Finally, the results of the seismic azimuthal analysis were corroborated with the well information and core data, demonstrating that the proposed work is effective in estimating the fracture orientation and relative fracture density from the P-wave seismic data. Presentation Date: Tuesday, September 26, 2017 Start Time: 2:40 PM Location: 360D Presentation Type: ORAL