This study identified and correlated hydrocarbon bearing reservoirs, interpreted geological structures and petrophysical parameters and described facies and environment of deposition using seismic and well log data. These were with a view to assessing the impact of reservoir heterogeneity on petrophysical parameters and to determine the hydrocarbon potential of “Devo” Field, Niger Delta. Porosity, permeability, water saturation, net-to-gross, and hydrocarbon saturation with values
ranging between 25.0 and 26.2%, 735.0 mD and 9019.4 mD, 15.3 and 67.5%, 49.6 and 57.3%, and 32.1 and 84.7% respectively. The Thomas-Steiber shaly-sand model analysis revealed that laminated shale was widely distributed all through the “DEVO” Field reservoirs. Despite the dominance of laminated shale, the reservoir quality from porosities (26.0%, 26.2%, and 25.4%), permeability (5264 mD, 4419.8 mD, and 3658.8 mD) values revealed very good to excellent qualities according to classifications made by Levorsen. Structural framework interpretation showed that sealing fault closure which includes the growth faults F12, F13, and F17 with antithetic faults F18 and F22 constitute the structural heterogeneity influencing oil trapping. Utilizing Amaefule's technique, the crossplots of Reservoir Quality Index and Normalized Porosity indicated
increasing reservoir quality in relation to the normalized porosity. Facies description demonstrated that five different facies (channel, tidal channel, mouth bar, shoreface, and tidal flat) were associated with the reservoirs and their environments of deposition were categorized as fluvial and shallow marine environments. The volumetric estimations showed that Reservoir 1 closures have Prospects 1 (241.6 Million of Stock Tank Barrels, MMSTB) and 2 (78.1 MMSTB) in terms of calculated Stock Tank Original Oil-In-Place (STOOIP). Reservoir 2 closures have Prospects 1 (250.6 MMSTB) and 2 of (127.7 MMSTB), while Reservoir 3 closures have Prospects 1 (48.8 MMSTB) and 2 (63.2 MMSTB) in terms of the calculated STOOIP.