A physical modelling study of time-lapse AVO signatures

Shahin Jabbari, Kristopher A. Innanen

Physical modeling can be used to validate the reflectivity predicted with different theoretical methods. We acquired a physical model experiment simulating a time lapse problem to investigate our theoretical results. The baseline survey has been modeled with plexiglass and PVC slabs resembling the cap rock and reservoir. The PVC slab has been replaced with a phenolic slab to resemble the monitor survey in which the reservoir had been gone under geological-geophysical changes during the time. Picked amplitudes from plexiglass-PVC and plexiglass-phenolic interfaces are corrected for geometrical spreading, emergence angle, free surface, transmission loss, and radiation patterns. The results for baseline survey, monitor survey, and their difference representing the difference data in time-lapse are analyzed. The linear and higher order approximations for difference data derived theoretically using perturbation theory and Zoeppritz equations were provided from the companion paper (Jabbari and Innanen 2012). These approximations are compared with the model data for validation. Results showed that the higher order approximations are more comparable with the model data which emphasize on including higher order terms for difference data calculations in time-lapse.