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Abstract The study aims to deduce the structural regime of the Miocene rocks and to evaluate the reservoir characteristics of Miocene formations in Belayim Marine oil Field, which cover an area of about 260 square kilometers southeast of Suez city in the Gulf of Suez, Egypt. The available data include forty seismic reflection section covering the study area which consist of twenty trace directed toward the NNE-SSW direction and twenty line directed toward the ENE-WSW direction, The composites and normal electric logs data of ten wells, which are used for subsurface, and petrophysical analysis. These wells named 113 - M - 13, 113 - M - 21, BM - 52, BMNE - 2, 113 - M - 56, 113 - M - 52, BM - 56, BM - 68, BM - 70 and BM - 85wells. The structural analysis involves the construction of structure contour maps, in term of time and depth, on the tops of Rudeis, Kareem, Belayim, South Gharib and Zeit formations that show five structural closures on the five tops as inferred from seismic data. These closures are dissected by faults of different trends. These faults constitute grabens, horsts and step-like structures. Statistical trend analysis of faults on tops of Rudeis, Kareem, Belayim, South Gharib and Zeit formations reveals that the area is affected by Suez trend while the other trends such as Aqaba, East African, Najd, Syrian arc, and Tethyan are affected the area but with a decreasing order. The subsurface geological studies are achieved for Rudeis, Kareem, Belayim, South Gharib and Zeit formations through constructing subsurface maps of sandstone isolith maps, sandstone percentage maps, shale isolith maps, shale percentage maps, , clastics percentage maps, salt isolith maps, salt percentage maps, anhydrite isolith maps, anhydrite percentage maps, limestone isolith maps, limestone percentage maps, non clastics percentage maps, sand / shale ratio maps, triangle facies maps and isopach maps. Six correlation charts and two panel diagrams, as well as, six structural cross sections are constructed to illustrate the thickness variation, lithofacies changes and structural elements that affected the study area. The study area reflects four widespread regional unconformity surfaces, the northeast dip regime of the pre Miocene strata and many normal faults forming grabens, horsts and step structures. The lithofaceis maps shows the presence of deep marine facies during lower Miocene deposits changed to lagoonal to deep marine condition during Middle Miocene. Isopach maps show the increasing thickness of the Miocene formations from the base to top. Petrophysical studies on the reservoir rocks play an important role in the discovery, evaluation and distribution of the productive zones. The petrophysical properties of rock depend mainly on depositional environment, mineralogy, geology and pore space framework. Well log data are interpreted for estimating the total gross thickness, net pay thickness, total porosity, effective porosity, shale volume, water saturation, hydrocarbon saturation, bulk pore volume and oil in place indicator. The petrophysical analysis of Rudeis, Kareem and Belayim formations concluded that the Rudeis and Kareem Formations are good reservoirs on the other hand; Belayim Formation contains good reservoirs and sealing rocks. Three-dimensional models constructed for Belayim Formation to illustrate the previously mentioned petrophysical parameters in the X, Y and Z directions across the Belayim reservoir. Matrix analysis for Rudeis and Kareem formations used to explain the different types of reservoir rocks through neutron-density, neutron-sonic and sonic-density crossplots that indicate the presence of sandstone, shale, limestone and dolomite rocks with different proportions. The mineral composition of the reservoirs were studied through the three log reading cross plot using M-N cross plots which illustrates the presence of quartz, calcite, dolomite and anhydrite minerals. Finally, the Miocene section considered as a good example of source, reservoir, and seal rocks of hydrocarbon. |