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Abstract The Gulf of Suez is the largest part of Egypt’s distinct oil provinces at oil production and reserves (Schlumberger, 1995). The Gulf of Suez-Red Sea basin is an excellent example of continental breakup and opening of new oceans (Moustafa, A. R. and Khalil, S.M., 2020). Zeit Bay field is located at the southwestern margin of the Gulf of Suez. It is located between longitudes 33° 32` and 33° 36`E and latitudes 27° 42` and 27° 47`N. It is mainly situated in shallow water of depth up to 65ft with a part of the field extends on land at Ras-El-Behar. The field was discovered in June, 1981 and the hydrocarbons are produced from all porous and permeable intervals from Hammam Faraun member of Belayim formation down to Precambrian Basement. The present study aims to evaluate the carbonate hydrocarbon reservoirs at Zeit Bay oil field through integrating the well logging and seismic data. About twenty 2D seismic lines and four wells (ZB-C3, ZB-A7, ZB-D1, ZB-B2) have been used for seismic interpretation by Petrel (2017.3) Software. The interpretation was limited to the area surrounding the wells. The main target of seismic section data interpretation involves the determination of the geologic significant features of the subsurface (Sheriff and Geldart, 1995). Depth structure contour maps are constructed to show the different structural features present in the area. Petrophysical evaluation was done for Rudies and Belayim Formations and the petrophysical parameters were estimated using Techlog (2015.3) Software. These logged data have been recorded, tabulated and prepared in (LAS) file formats to be ready for the petrophysical analysis. The logged data in these wells include various types of well logs as Caliper log (CAL), Gamma ray log (GR), Resistivity, Porosity logs (RHOB, NPHI, DT), Natural Gamma ray Spectrometry (NGS) and the photoelectric factor log (PEF). The Techlog (2015.3) Software was used to figure out the precise reservoir rock petrophysical parameters, which subsequently used for carbonate reservoir evaluation. Lithostratigraphically, the stratigraphic section of the Gulf of Suez includes three tectono-stratigraphic sequences (Hamimi, et al., 2020). These are pre-rift, synrift, and post-rift. The stratigraphic succession of Zeit bay field is similar to the sequences presented elsewhere in the southern part of Gulf of Suez basin. Zeit Bay stratigraphic column is ranging in age from Pre-Cambrian basement to Recent (Fig. 5) (SUCO, 1988), where reservoir units are ranging in age from Pre-Cambrian basement to Hammam Faraun (Middle Miocene). The Kareem/Rudeis carbonate reservoir overlies the Basal Miocene sand. It attains a maximum thickness of 600 ft. and pinches out laterally on the crestal part of the structure. The Belayim evaporites form the vertical seal of the carbonates. The Kareem/Rudeis strata show deep water shales on the flanks and carbonate on the crest (Darwish, et al. 2016) made a detailed chronostratigraphic, sedimentologic facies analysis and wireline log calibration to study the evolution of the Miocene oil-bearing syn-rift sequences in Zeit Bay Field. Depth structure contour map was constructed for top Rudies, top Belayim and basement wash , the maps show a NW-SE elongated dome intersected by semivertical normal clysmic faults, this elongated dome represents the structural trap in the field. Petrophysical evaluation showed that Rudies Formation is the main reservoir in the area. Petrophysical evaluation was done for Rudies Formation and the petrophysical parameters were estimated. According to the petrophysical analysis, Rudies Formation is subdivided into two main zones; the first has low (Gammma ray) GR value (Rudies 1), the second has high GR value (Rudies 2). Rudies1 has an effective porosity ranging from 15.9% to 20.3%, content of shale ranging from 2.5% to 8.1%, water saturation ranging from 4.1% to 15.6%, and net to gross value ranging from 73.9% to 97.4%, where Rudies2 has an effective porosity ranging from17.7% to 21.4%, content of shale ranging from 2.8% to 8.8%, water saturation ranging from 7.3% to 19.6%, and net to gross value ranging from 68.9% to 87.8%. The histrograms were made for the calculated petrophysical parameters (PHIE total and effective), water saturation, hydrocarbon saturation, and shale volume at three wells (ZB-L1, ZB-C3, and ZB-B7). These histrograms shows how the petrophysical parameters differ from point to another point and reveal the heterogenity of some zones, like Rudies 1 and Rudies 2. The lateral variation of the petrophysical parameters and the hydrocarbon occurrences can be presented and interpreted by iso- parameteric maps. These maps show the various distribution of a cumulative presentation of the areal extension of each of the petrophysical and fluid saturation parameters (Net pay, Effective porosity, Shaliness, Hydrocarbon and Water saturation) for Rudies 1 and Rudies 2 reservoirs. At last, Rudies1 and Rudies2 are very good reservoirs. In general, Rudies Formation seems to be a homogenous reservoir, however, it is a heterogeneous reservoir that differs both laterally and vertically at its petrophysical characteristics and lithology. |