PETROPHYSICAL EVALUATION AND DETERMINING THE DEPOSITIONAL ENVIRONMENT OF OBAMA FIELD SOUTH-WEST NIGER DELTA

ABSTRACT
The logs from three wells of Obama Field, offshore south-west of Niger Delta Basin were studied for the purpose of evaluating the petrophysical properties and interpreting the depositional environments. The analyses carried out involve delineation of lithologies, identification of reservoirs and fluid types, wells correlation and determination of petrophysical parameters of identified reservoirs and interpreting their environment of deposition. A suite of wire-line logs comprising gamma ray, resistivity, density and neutron logs for three wells from Obama field were analysed for reservoir characterisation of the field. Interactive Petrophysics software (IP 3.6) was used for well Log analysis and Petrel software for the reservoir correlation. In addition, the depositional environments were interpreted using gamma ray log. Four reservoirs namely: A, B, C and D were delineated with their tops and bases in all the wells. The analysis indicates the presence of oil and gas in the reservoirs. The computed petrophysical parameters across the reservoirs in the field gave porosity as ranging from 18.880% to 35.225%; permeability 85.08md to 2179.21md and hydrocarbon saturation 63.4% to 92.6%. The environment of deposition inferred from the gamma ray log ranges from barrier bar, distributary channel fill, fluvio deltaic plain and tidal flat to tidal channel fill.