Petrophysical Evaluation and Depositional Environments of Reservoir Sands in an Oil Producing Field, Onshore Niger Delta, Nigeria

Abstract

Optimal hydrocarbon recovery depends strongly on predicting the reservoir quality and reservoir drive mechanism, and this could be achieved by petrophysical analysis. This research evaluated the petrophysical properties of reservoir sands in an Oil producing Field, onshore Niger delta, Nigeria using petrophysical techniques. Results from the Petrophysical evaluation, showed that the average porosity values of the reservoirs ranged between 0.15 and 0.24 while average water saturation for the three reservoirs ranged from 19% to 44%. Reservoir D_3000 has the largest accumulation of about 952 MMSTB while reservoir D_1000 gave the least accumulation of about 727MMSTB. The environment of deposition was interpreted using gamma-ray log motif. Reservoir D_1000 shows a blocky gamma ray motif that suggests deposition from a steady energy, which can likely be a channel deposits. Reservoir D_2000 sands showed an obvious funnel shape gamma ray log motif by it coarsening upward attribute, which can likely be interpreted as a shore face environment. Reservoir D_3000 is the deepest and the thickest of the three reservoir sands, the gamma ray log motif displayed a blocky shape which can likely be interpreted as bar deposits and channel sands. This study reveals that Channel Sands, Bars and Shore face are good sites for exploration and production of hydrocarbon.