Reservoir Characterization of the Upper Cretaceous Abu Roash and Bahariya Reservoirs, Main Abu El-Gharadig Oil Field, North Western Desert, Egypt

Abstract

T HE study area is located in Abu El-Gharadig basin, between 29° 40’ and 29° 45’ N latitudes and 28° 25’ and 28° 32’ E longitudes. The study aims to evaluate four formations that are located in the middle part of Abu El-Gharadig Basin, North Western Desert, Egypt. This is carried out by conducting petrophysical analysis, to investigate the late Cretaceous hydrocarbon-bearing reservoirs of the Abu Roash “D” and “E” Members, and the Bahariya Formations. To achieve the aim, Interactive Petrophysics software (IP) version 3.5 helped in well-logging evaluation providing the density-neutron and the M-N cross_plot, to characterize the porosity and lithology of the reservoirs and the effect of shale and secondary porosity on the potentials of these reservoirs. In addition, the software presents analogs indicating the vertical distribution of petrophysical parameters for the studied well and to show the distribution of shale volume, porosity, water saturation and hydrocarbon saturation and identify the oil-bearing zones. Analysis of the petrophysical parameters report that, the Abu Roash “D” reservoir is mostly limestone with sandstone and shale lithology, while the Abu Roash “E” reservoir is primarily sandstone, with shale, limestone and dolomite lithology. The reservoirs in the Upper and Lower Bahariya are mostly sandstones, with argillaceous and calcareous types of cement. The shale volumes in the Abu Roash ( D and E ) Members and Upper and Lower Bahariya Formation are 0.9 – 3.8 %, 8.2 – 13.7, 7.2 – 15.2, and 9 – 15.5 %, respectively, and the effective porosities are 6.7 – 14.7 %, 13.9 – 18.1 %, 13.1 – 15.5 % and 11.4 – 15.5 %, expressing a good reservoir quality of the zones. Petrophysical data from the Abu Roash and Bahariya reservoirs are shown on analogs, to identify the most effective thicknesses with good hydrocarbon potential.