Time-Lapse Seismic Amplitude Analysis for Enhanced Prospect Definition. – C.A. Edoja, J.O. Ebeniro, C. N. Ehirim, W. S. Ajiduah and T. Dagogo
Time-lapse seismic amplitude analysis were carried out on HD2000 reservoir located in the land/swampy field of Nembe creek, Niger Delta by integrating AVO modeling from well and horizon attribute analysis from 4D seismic. The aim of the study was to monitor water flooding, map reservoir compartmentalization, and detect by-passed oil zones. Initial fluid sensitivity analysis revealed seismic amplitude to be robust in characterizing fluids. In effect, RMS seismic amplitudes were extracted along two time horizons (HD2_version2 and HD2 respectively) tracking the top and base of the reservoir, from the baseline, monitor and difference volumes. RMS amplitude slices generated along HD2_version2 showed that the existing wells are located within low amplitude environment, an effect that is indicative of hydrocarbon extraction. HD2 horizon RMS amplitude slices revealed some elements of high amplitude around two wells in both baseline and monitor data, and the 4D effects associated with production were evident on the difference slice. The results of the 4D seismic analyses revealed four probable by-passed oil zones; one in HD2_version2 horizon slice and three in HD2 horizon slice. These zones are considered as new development targets.