Water saturation is a key parameter in evaluating oil and gas reservoirs and calculating OIIP and GIIP for petroleum fields. The late Cretaceous Bahariya reservoir contains variable amounts of clay minerals. Bore hole logs are affected with those clay minerals particularly the density and resistivity logs. Several methods are acknowledged to determine the true water saturation from well logs in shaley sand reservoirs. Each method assumes a sort of corrections to amount of shale distributed in the reservoir. The scope of this petrophysical study is to integrate core analysis and bore hole logs to investigate the characteristics of water saturation in the Bahariya reservoirs. Comparison between most of the significant shaley sand methods is presented in this research. Reservoir lithology and mineralogy are explained by Elan-model while bore hole images are used for fine-tuning the electrofacies. Siltstone, shaley sand and clean sandstones are the main electrofacies that is characterizing the Bahariya reservoir rocks. For accurate saturation results, some core samples have been used for validating the log-derived water saturation. Dean stark and cation exchange capacity experiments are integrated with bore hole logs to calculate the error in water saturation for each method for best calibration. The successful integration between logs and core measurements led to convenient log evaluation and accurate understanding for the Bahariya reservoir in the prospective part of Abu Gharadig basin.

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In this research an integrated reservoir study was performed on one of the successful water flood projects in Bapetco; The NE-Abu Gharadig-1 field which passes through a several phases of development started with appraisal and delineation, initial development (fast track), re-development phase and last phase of reservoir simulation. The conducted field re-development activities increase the EOR expectations and tackle the remaining reservoir potential. Until the moment 58 wells were drilled in this field 29 oil producer, 26 water injector and 3 water source wells. Different accumulations and segments were interpreted; these segments did not indicate full communication as the thinly bedded Bahariya sequence of 200 meter thickness shows a wide range of reservoir properties and heterogeneity including porosity, permeability and hydrocarbon saturation. Geo-cellar modeling approach was beneficial in this field in order to link the static and dynamic data until reaching a certain level of match and harmony. Twelve productive zones were interrelated through an attempt to construct structural and stratigraphic facies distribution framework guided by cores and BHI. The 3D geo-cellar modeling was applied to the probable cases and prospective blocks. Petrel data analysis tool was activated in order to control the probability distribution in property modeling. Further reservoir simulator was used to incorporate the engineering data as pressure and production; therefore optimal development strategies are aligned with the findings and forecasts of each reservoir sector. The results indicate a massive variation in vertical and lateral OIIP distribution and URF which is ranging from 16 % to 40 % on the best chances; this variance controlled by the reservoir architecture, compartmentalization, reservoir rock types, relative permeability curves, minor faults and fractures associated with different stress regimes. The WF pattern fitting and placement were optimized to overcome the geological constrains by additional two phases of infill wells. The results provides a robust reserves stair case through a multi-phases of development and modeling to increase the field production life, improve pattern flood, optimize enhanced recovery and smooth operation.

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