RESERVOIR CHARACTERIZATION AND HYDROCARBON POTENTIALS OF GEOZFIELD, WESTERN NIGER DELTA BASIN, NIGERIA

Abstract

Reservoir sand bodies were evaluated from log suites consisting of gamma ray, resistivity, density and neutron logs of three wells (Geoz 01, Geoz 02, and Geoz 04). The aim of the study was to determine the reservoir characteristics and hydrocarbon potential of the reservoirs, the objectives were to identify the lithology of the Geoz Field, evaluate the petrophysical properties, identify the hydrocarbon bearing zones and predict the reservoir quality. Based on the Gamma ray log evaluation, Geoz Field revealed the presence of sandstone and shale intercalations, three reservoir sand bodies were correlatable. The reservoirs were found to be
continuous across the wells with an average gross thickness of 300ft (91.1 m), 64ft(20 m) and 53ft(16 m) respectively. The fluid types in the reservoirs based on the neutron density log signatures were basically water, oil and gas, identified as hydrocarbon bearing zones. Based on their petrophysical properties, Reservoir A has an average Net to Gross (22.17 %),Porosity Ø (29.0 %),Permeability K (3894.47 md), Water Saturation Sw (9.0 %) Hydrocarbon Saturation Sh (91%); Reservoir B an average Net to Gross (36.23 %), Ø (31.0 %), K (4039.80 md), Sw (8.0 %) and Sh (92%) while Reservoir C has an average Net to Gross ( 27.65 %), Ø (29.0%), K(4015.61 mD), Sw (6.0%) and Sh(94%) respectively. The cross plots of the reservoirs A,B and C in the Geoz Field indicate compaction and primary mineralogy influenced by palaeodepositional environments. From this study, the reservoirs may be considered a good quality for hydrocarbon prospects