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Abstract The present study deals with evaluation of the Surface and Subsurface structural framework and reservoir characteristics. This is to evaluate the hydrocarbon potentialities of the study area Qasr oil Field (Shushan basin) which is located at the north Western Desert of Egypt, about 7.5 Km south of the Mediterranean coast. The data include 2D and 3D seismic data, composite logs, electrical logs, cores and plugs results from the available exploration wells were utilized in this study. The AEB-3D rock unit is a part of the Lower Cretaceous Alam El Bueib Formation, and is considered as the main oil producing reservoir in the study area. The Lower Cretaceous Alam El Bueib sand (AEB) was interpreted, as stacked channel and point bar fluvio-deltaic sands, with interbedded shales and some limestones or dolomites. The oil is trapped in stratigraphic or structural three-way dip closures or a combination of both. This work aims to find new drilling sites for further field development in the future, where the reservoir compartmentalization model can be updated, based on the data available from new wells. Furthermore, the analysis of electric well logs, reservoir pressure measurements and sedimentological core descriptions can help in the detection of sand channels and to predict their directions. Lithological interpretation showed two sand zones, with average thickness of 30-50 ft. in most wells. They are separated by inter-zones layers of about 10-50 ft. (distance). The interpretation of well logs, coupled with the core descriptions, showed that, Alam El Bueib-3D rock unit is subdivided laterally into two sand channels. Both are deposited in a high energy tidal environment. Well correlations, mapping and analysis of the pressure measurements showed that, the directions of these channels are most probably northeast to southwest. In addition, the effect of stratigraphy and structures led to a number of reservoir compartments with varying pressure values, either vertically or horizontally. Picking and interpretation of the ten horizons from Lower Safa to Dabaa Formation which done by tying seismic data (time) with well data (depth). Seismic profiles illustrated the Surface and subsurface structural framework of the Lower Safa and Alam El Buieb reservoirs. It can be demonstrated that 3D structural modeling described the structural compartments of the study area by displaying cross sections along any direction and through any well location of the model’s data base. This can be used to propose locations for future exploration wells in the area. Structurally, Qasr oil field is represented by horsts and grabens. Large accumulations of hydrocarbons have been trapped along the NE-SW elongated, narrow and asymmetrical tilted fault blocks. The reservoir Petrophysics characteristics of the present study deals with the determination of the reservoir properties by using different log responses imply good reservoir quality. Petrophysical properties of Lower Safa and Alam El Buieb reservoirs are represented in the form of isoparametric maps which include shale volume (Vsh), gross sand, total porosity, effective porosity, water saturation (Sw), net pay, net/gross thickness, hydrocarbon saturation (Sh), residual hydrocarbon saturation (Shr) and movable hydrocarbon saturation (Shm) to show their horizontal distributions of the Lower Safa reservoir. The well log analysis of the Lower Safa and Alam El Buieb reservoirs using different types of the cross-plots such as density neutron that shows the Lower Safa reservoir is mainly sandstones with some calcareous cement. According to the pressure analysis, the hydrocarbon type of Lower Safa reservoir in Qasr oil Field field is mainly light hydrocarbon. The source and reservoir rocks are all sandstones, while the seal rocks are the local intra-formational shales. The oil in sandstones is of 22-35 API. Porosity, permeability and water saturation ranges of the reservoir pay zones are 15-30%, 100-300 md and 20- 50%, respectively Data integration of all input data with each other by the Petrel TM , Schlumberger’s software. The results of this study showed improve in the reservoir characterization of the Lower Safa and Alam El Buieb Formations, help to identify potential hydrocarbons present and hence will aid increasing the cumulative reserves in the concerning area. The integrated data has been used to support the exploration and development in the future field planning. |