الفهرس 
Geology of The AreaOnly 14 pages are availabe for public view
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Abstract
The study is dealing with geological and geophysical studies for the Miocene reservoir in El Tamad oil Field, onshore Nile Delta. This study is performed on Qawasim reservoir, as it is include oil and gas bearing reservoir in El Tamad Field. The area under study lies in the eastern part of the Nile Delta, east of Dimmetta branch. It extends between latitudes 30º 55’ to 30º 57’ N. and longitudes 31º 27’ to 31º 28’ E. The study area includes El Tamad Field, which lies south of Abu Madi, East Delta and Mansoura development leases, close to the boundary of SE Mansoura concession in the onshore Nile Delta, Egypt. This field, was discovered in 2005 with a reservoir sequence dated as Messinian in age and considered the firstly proven field for the presence of oil in the onshore Nile Delta. This discovery reoriented the hydrocarbon exploration strategy in the Nile Delta, changed the philosophy of Messinian entrapment and petroleum system, so, starting a campaign between all petroleum companies for oil seeking. This study includes five chapters as follows:
The first chapter deals with geology of the area
This part considers a general overview for the geology of the area; the general stratigraphic setting of the Nile Delta, in some details the stratigraphic framework for the study area and listed the obvious lithological criteria for the zone of interest. On the other hand, highlight the major structural elements, that affected on the Nile Delta in general and particularly El Tamad Field.
The second chapter deals with structure studies
This chapter focusing on the Hinge Zone “main structural lineament” that affected on Nile Delta, particular El Tamad Field. Delineation the structure for the study area had been done, in order to highlight the best locations for hydrocarbon accumulations by picking the seismic reflectors of the top Messinian reservoir. The interpreted seismic horizons are controlled by the well data (Vertical Seismic Profile ”VSP”).
On the other hand, geological structures that affected on El Tamad reservoir had been traced, where the impact of these structures is clear on facies distribution, sedimentation pattern and hydrocarbon occurrence. This impact had been reflected through several plane views and vertical views (i.e. maps and cross sections).
The interpretation is verified the presence of favorable thickness of Messinian deposits, which has prospective hydrocarbon potentiality. This vision is confirmed by solid evidences, despite of the structural effect of the Hinge Zone and erosion process, which had been reported through the recent published papers. The structural interpretation for Messinian level indicates the presence of northern and southern culminations, where the southern one is confirmed its potentiality by El Tamad discovery, while the northern closure represents prospect location for hydrocarbon accumulation. The Messinian sediments in the study area are seen as wedged shape towards north, resulted from rotation on faults planes.
The third chapter deals with Sequence Stratigraphy studies
This part carried out by utilizing the biostratigraphic data, which allowed for detecting Maximum Flooding surface in the study area and precise identification for the age of El Tamad reservoir to be Early Messinian. Also through this chapter, Cyclostratigrapic curve had been used for better understating the sedimentation history for the penetrated section, in which shows, the Messinian section is capped by Maximum Flooding Surface, in addition to Highstand system tract of Kafr El Sheikh Formation and underlies by Highstand system tract of Tortonian section. Qawasim reservoir had been interpreted to be Lowstand system tract and situated between Trangrassive system tract “upper boundary” and Highstand system tract “lower boundary”. More details, Qawasim reservoir is consists of three sequential Lowstand Parasequences, that are distributed allover the study area and each one had a distinguishable facies.
On the other hand, detailed seismic stratigraphic analysis had been done for the available seismic reflection profiles that integrated with lithological data. Facies delineation across the study area had been performed for the Qawasim reservoir Parasequence zones, which are described seismically through several seismic sections and detecting the internal reflection configuration pattern for Messinian sedimentary package.
The fourth chapter deals with petrophysical analysis
The main target of this chapter is to constructing the petrophysical model for the studied reservoir. This had been done by defining basic information needed for reservoir evaluations, such as cementation factor “Archie constant”, saturation exponent, cementation exponent and water resistivity. Core analysis–electric logs integration had been performed for all model volumetric outputs. Staring with establish the clay volume qualitative and quantitative analysis. Untraditionally, the clay volume calculations had been checked by using Nuclear Magnetic Resonance log. On the other hand, determinate clay type occurrence within the reservoir, which affected on the reservoir quality and the selection of calculation method of water saturation. The same qualitative and quantitative analysis were done for porosity, permeability and water saturation (Sw).
Hydrocarbon zones and fluid type detection for the reservoir interval had been done through the acoustic and nuclear logs responses. In addition to, the pressure depth gradients and confirmed by fluid sampling; where through this study, the pressure depth gradient for defining oil fluid had been updated. Another application of pressures versus depth plots relationships for all drilled wells is monitoring the reservoir behavior through production; where by the comparison of pressure and the fluids contacts through each well in the study area, the reservoir depletion had been clarified from the fluctuation of average reservoir pressure against time.
The important reservoir petrophysical properties (clay volume, effective porosity & permeability) had been plotted in vertical views, in addition to contouring the average values of each one of these properties for better display its lateral distribution allover the study area.
The fifth chapter deals with well data analysis and integration with the reservoir characterization for building depositional model
This chapter includes all interpretations for the results of data integration from core description with electric logs, particularly, Formation Micro Image” and Biostratigraphy. Which indicated that, the reservoir is deposited under shallow marine environment; the shoreface deposits represent the major facies in El Tamad area and dissected with oscillated tidal effect localized in certain parts of the field, in addition to, lagoonal sediments.
Sedimentary model for El Tamad reservoir had been constructed using distinctive studies, as integration of reservoir characteristics, sedimentary features and texture analysis. where the shoreline direction had been defined to be in east–west direction and the tidal current is detected to be NNW–SSE direction (i.e. perpendicular to this shoreline). It is worth to be mentioned that, the depositional facies had been identified with the assessment of rock physics
Several sketchmatic diagrams are display the depositional stages in the study area and implications for reservoir characterization and simulation. The process that controlled reservoir characterization are the tectonic, sea level change, tidal effect, biological activity and diagensis (processes of porosity loss and gain), in which through all these factors, the definition for the direction of reservoir quality enhancement is detected.
Finally, the petroleum system elements for the study area is defined through the geochemical analysis, which suggest that the oil has been generated from Late Cretaceous to Oligocene rocks at the early stage of the mid-oil window maturity. The source rock deposited in shallow marine environment under oxic to sub-oxic conditions contains mainly terrigenous organic matter of mixed type II/III kerogen. The Pliocene shale is an ideal vertical seal in addition to, intra-formational Messinian shale, while lateral seal is controlled by downdip, facies variation and fault sealing.