Abstract

Electrofacies and depositional systems of sequence penetrated in ‘Ray’ Field, Niger Delta were analyzed, using well log and 3-D seismic data, with a view to enable accurate prediction of source and reservoir rocks in the study area. Lithofacies were delineated through analysis of well logs using signatures of gamma ray, cross-plot of neutron-density logs and seismic facies analysis. The identified lithofacies were subjected to electrofacie analysis through diagnostic characteristics of gamma ray log indicative of a given depositional environment. Sands of different environments were subjected to seismic attribute and petrophysical analyses to assess the hydrocarbon potentials of such reservoirs. Results showed the presence of four lithofacies: Shale, Heterolithic, Shaly-Sandstone and Sandstone Facies. The electrofacies analysis revealed five depositional systems of Shoreface, prodelta, distributary, tidal and fluvial systems. Lateral variations of lithology and facies distribution, as well as presence of channels were imaged by seismic attribute. The sand units of the distributaries and tidal channels having thickness of 70 m and 65 m, and porosity of 16% and 24% respectively were viewed to have good quality for hydrocarbon reservoir.