| Abstract: |
The Gulf of Suez region represents one of the most prolific and prospective oil provinces in Egypt. It has a long history of hydrocarbons production. The study area comprises the extreme northern offshore portion of the Gulf of Suez and lies between LatitThe main targets of the present study are; (a) Definition of the subsurface geological and structural framework which controlling the hydrocarbon generation and accumulation in the study area, (b) delineation of the structural elements and the thickness vThe available data include geological and geophysical information. The geological data consist of seven composite well logs drilled in the area. Meanwhile, the geophysical data include; the Bouguer gravity and total field intensity aeromagnetic maps (scalThe stratigraphic sequence of the sedimentary rocks of the area as deduced from the subsurface composite well logs, ranges in age from the Permo-Carboniferous to Recent. This sequence is unconformably overlying the basement rocks, and it is variable in bo(i) Basement_ Permo- Carboniferous ,(ii) Permo- Carboniferous _ Triassic,(iii) Lower Cretaceous _ Eocene,(iv) Pre Miocene _ Lower Miocene and(v) Middle Miocene _ Pliocene unconformities.The sedimentary sequence of the Permo-Carboniferous age was deposited unconformably underlies a thin Triassic sediments. The Jurassic sediments are represented by Masajid Formation underlying the Lower Cretaceous continental Nubian sandstone (A series). TForty one seismic profiles are interpreted to delineate the tectonic framework of the selected area. Twenty four seismic lines termed GS202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, 236, 238, 240, 242, 244,246 and 24The interpreted seismic sections display well the subsurface structural configuration of the study area. Close investigation of these sections show that the area is affected by a group of normal faults of different extensions and throws, these faults formThree two-way time (isochronous) maps are constructed on the tops of the Lower Miocene formations (Nukhul, Rudeis and Kareem) because of their productivity importance in the Gulf of Suez oil province. In addition, three average velocity gradient maps on tIn addition, the structure contour maps indicate that the folding plays a minor role in the structure setting of the Lower Miocene (Nukhul, Rudeis and Kareem) formations, except in the northeastern parts. This may be due to the Syrian Arc tectonics which The potential field data on which the present work based on include the Bouguer gravity and the total field intensity aeromagnetic maps. These data were interpreted to execute the previously mentioned tasks.Before applying the qualitative and quantitative interpretations, the total field intensity aeromagnetic map is reduced to the north magnetic pole (RTP) to locate the magnetic anomalies directly above their causative bodies. Moreover, reduction to the ZerThe qualitative interpretation of the Bouguer gravity map includes the visual inspection to get rapid and rough concepts about the geological structure of the investigated area. It shows that there are two negative anomalies (the larger one is located in The qualitative interpretation of the reduced to the north magnetic pole (RTP) map shows alternated positive and negative anomalies trending mainly in the E-W, ENE and WNW directions. These anomalies may be indicating the structural pattern and/or the rapIn addition, three qualitative techniques of interpretation are applied to the potential field data (maps) to enhance the anomalies, by condensing the trends and make them sharper. These techniques are considered to be directional filtering techniques. ThThe edge enhancement technique is concerned with the edge of the anomalies, where it becomes sharper and easily to be defined in shapes, sizes, extensions and trends. Thus, the particular illustration of the edge enhancement of the Bouguer and RTP maps reThe sun shading technique is employed in order to enhance the directional features of the potential maps data, and to evaluate them as if they are a three-dimensional topographic surface. The filter tends to exaggerate and enhance the anomaly shapes and tThe strike filter technique is applied after the application of edge enhancement and the sun shading techniques. This technique reflects that the area is affected mainly by Suez, Syrian Arc and Najd trends, as deduced from Gravity data and by Tethyan, SyrThe quantitative interpretation includes:1-The trend analysis technique is applied on both Bouguer and RTP relative to zero level maps using the first horizontal gradient (Vxz) for 46 and 51 profiles, taken form the Bouguer and RTP maps respectively in a grid pattern with spacing of 2 km apart iDetected trends interpreted from both Bouguer and RTP aeromagnetic maps were used to visualize the tectonic history of the area by reasonable model explaining the tectonism in the Red Sea region during its entire geologic history. This suggestion is to ex2- The regional - residual separation: different methods of regional – residual separation are applied on both the Bouguer gravity and the RTP magnetic maps in order to separate and bring the shallow anomalies (structures) from the deeper ones. These methThe residual gravity maps indicate that there are new negative and positive anomalies with increasing depth within the Gulf of Suez and the area can be considered as two main basins. The northern basin is located around GS56-1A well (Darag Basin), while tThe residual RTP aeromagnetic maps show a great numbers of positive and negative anomalies. These anomalies may reveal the variation in the chemical and mineralogical composition of the basement rocks. The positive anomalies may associated with the basic The positive and negative anomalies, deduced from the application of the SVD method on the gravity and magnetic data using Rosenbach’s and Gunn’s techniques, are correlated with the productive and dry wells drilled in the study area.. there are many posit3-The depths to the basement rocks are calculated along twenty two magnetic profiles covering almost of the study area using different techniques of depth estimation such as straight slope, peterיs, half width and tangent methods, besides, the spectral anIn addition, a near-surface intrusion depths are also calculated. they show that the maximum near-surface intrusion is about 2 km in the northern parts, while the minimum depths are located in the southern parts and have a depth of about 0.34 km.4- Euler deconvolution are used to locate the step-faults and estimate their depth allover the area using both Bouguer and RTP magnetic map. To give an idea about the boundaries of the sedimentary basins and the configuration evaluation of the sedimentary5- Two and half dimensions (2.5-D) magnetic modeling is applied on the RTP magnetic map along seven magnetic profiles trending in the dip (SW) direction. The theoretical (calculated) curves are computed and compared with the observed ones to get the real The magnetic susceptibilities map is constructed from the digitizing of the different stations along the profiles corresponding different susceptibility values. It shows small magnetic susceptibilities in the northern area (between Ras Misalla and Ras MatA tentative basement relief map is constructed using the average depth estimated from traditional methods and spectral analysis technique as well as the values digitized from the 2.5-D modeling profiles. It illustrates that the depth to basement is varied6- Two geologic structural cross-sections are constructed in the N-S and NE-SW directions depending on the available drilled wells to delineate the subsurface structural features along them. They show that the area is subjected to several tectonic movemenTentative basement structure map is constructed using integrations of all results obtained from the previous analytical and interpretation techniques on both gravity and magnetic data. It shows two highs parallel to the Gulf of Suez shoreline alternating Although, the study area has suitable conditions for hydrocarbon generation and accumulation, most wells drilled in the area are considered to be dry or not productive. Since the area have great thickness of sedimentary rocks (about 6000 m in Darag Basin)These reasons may be aided to the migration of hydrocarbons from the area to outside and to the adjacent oil fields, lies to the (onshore or up dip area) NE of the northern part of the Gulf of Suez, such as North Darag, Sudr, Matarma, Asl and other oil fiFinally, the study indicates that the area contains promising sites for the hydrocarbon accumulations, where it contains different geological structures, great thickness of the Miocene sediments with different depositional environments. Consequently, it i
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