A Rock Physics and Attenuation Analysis of a Well from the Gulf of Mexico Gary. Mavko, Stanford University, Jack Dvorkin*, Stanford University and Rock Solid Images, Joel Walls, Rock Solid Images Abstract The well selected for the application of our attenuation theory and extraction of attenuation attributes from seismic data is the Texaco well (API 177104132700) in Block 313 of Eugene Island in the Gulf of Mexico (Well 2700). The rock physics diagnostics indicates that the rock can be described by the uncemented (soft-sand) model. This model is used to predict the S-wave velocity that was missing in the original well data. The P- and S-wave inverse quality factors are computed according to our theoretical model. The ratio of these inverse quality factors (P-to-S) is small (on the order of one) in wet rock and large in the gas zone. The seismically-measured attenuation ratio may serve, therefore, as an indicator of hydrocarbons. The synthetic seismic traces computed using the well data and the ray-tracer with attenuation, specifically developed for this project, indicate that attenuation affects the seismic response and, therefore, can be extracted from real seismic data, including the P-to-P and P-to-S reflection amplitude.
