The concept of 4D seismic time-lapse generally involves acquisition of seismic data at different times over the same area to assess possible changes in the subsurface with time, such as fluid movement or effects of enhanced recovery.

This can only be achieved through a quantitative link between rock properties and seismic response. In order for seismic exploration to be more reliable in high-risk areas, one must understand the true geologic meaning of seismic amplitude. The final results were reported in terms of not only how reservoir fluids would interact under different conditions, but how the resulting impacts on the reservoir properties can be used as a reconnaissance tool to reveal important information prior to conventional 4D seismic survey.Īs exploration activities continue to shift offshore and towards more complex geologic settings, conventional seismic interpretation becomes increasingly ambiguous. Through fluid substitution based on Gassman's theory, 4D well-log and seismic effects were modeled from 4D attribute cross-plots with three variable parameters porosity, pressure and saturation, to aid the interpretation of time-lapse results. Dynamic rock physics templates were constructed to study the reservoir under different geologically plausible scenarios and to correlate relative changes in P-impedance and Vp/Vs to pore pressure, porosity, fluid contact changes and fluid saturation changes that may be anticipated in the reservoir production life history. First, static rock physics templates were generated from cross-plots of reservoir's elastic properties and rock physics attributes to characterize the reservoir in terms of lithology and pore fluid, as well as diagenetic factors. This integrated approach was applied to reservoir J1 of 'JAJA' field, offshore Niger Delta basin. Such a relationship is essential for reducing uncertainties during time-lapse interpretation and 4D monitoring. The aim was to create a quantitative link between pressure, saturation and seismic velocity, in order to clearly understand the dynamism within a reservoir during production. In this study, we incorporated rock physics techniques into seismic interpretation in the context of seismic time-lapse analysis.

Hampson russell fluid substitution