الفهرس 
REGIONAL GEOLOGIC SETTINGOnly 14 pages are availabe for public view
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Abstract
Abstract
This thesis represents an integrated seismic and well logging study for Yomna Field. This area is located in the north western part of East Bahariya concession which is located in the northern part of the Western Desert of Egypt. It covers an area of about 247 Km2 and is bounded by latitudes 29º 42’ and 29º 48’ N and by longitudes 29º 24’ and 29º 36’ E. This area was affected by tectonic deformational systems cause regional uplift, leads to lateral variation in the thickness of Khoman Formation and that in turn affects greatly the imaging of pre-Khoman; Bahariya and Abu Roash succession. The main purpose of this study is to overcome this imaging problem and delineate the structure style and hydrocarbon trapping in the study area using the 3D seismic and the available well data.
To achieve this target, the current study started with the description of the geological setting of the area, including the stratigraphic sequence and the dominating structures through a review for the previous geological studies. Then, 3D seismic data has been interpreted to construct time and depth structure contour maps on the top of Khoman, Abu Roash ”A”, Abu Roash ”D”, Abu Roash ”G”, Bahariya, and Alamein Formations aiding by the available well velocity data, to figure out the structural geometry in the area. 3D seismic data interpretation has been carried out using Petrel® 3D Seismic Interpretation Software. Fault patterns play an important role in the hydrocarbon potentialities of the area; therefore, 3D seismic coherence has been obtained and used for imaging discontinuities and following faults, dissecting the studied formation tops, laterally. Also, 3D structural modeling has been conducted to resolve the structural setting and hydrocarbon trapping in the study area.
Moreover, a comprehensive analytical formation evaluation system has been established for the available wells in the area to interpret the basic logging data for the deduction of the petrophysical parameters of the main reservoir rocks; Bahariya and Abu Roash ”G” Formations, such as porosity, shale content, water and hydrocarbon saturation based on a number of equations and empirical formulae. The bore-hole data analysis has been done using Interactive Petrophysics® (IP) Software.
The structure contour maps which were constructed from seismic data interpretation show that the area is affected by a set of northwest-southeast trending normal faults lead to uplift in the study area, represented by the low and high anomalies on the produced maps. Some of these faults die out at the top of Alamein Formation. However, there are some additional deep-seated faults present in Alamein. The structure contour map which was constructed on top Khoman shows that most of the above mentioned faults did not affect it. Thus, the flat lying Khoman layers are on-lapping onto the underlying, relatively steeply dipping, Abu Roash succession. This in-turn suggests that the structure has been formed pre-Khoman time of deposition. This illustrates the lateral variation in Khoman thickness all over the study area.
The obtained 3D structural model confirms the interpreted structure from the seismic. The major set of the northwest-southeast trending normal faults affect the study area, is believed to be produced as a result of the tectonics of the Paleozoic age. A major three-way dip closure appears on the top of Bahariya and Abu Roash ”G” Formations; the main reservoirs in the study area, in the northern part at East Bahariya-32A well. Also, East Bahariya-34 well having horst trapping style in the southwestern part of the study area. These closures reveal probable prospects. The depth structural contour map of Alamein Formation shows positive structure in the southwestern corner at East Bahariya-34 well, which indicate probable positive structure in the deeper formations, thus, more investigation is needed for the trapping style at deeper depths.
The pay zones have been identified through these reservoirs in the studied wells as a result of the quantitative interpretation. Bahariya reservoir represents the productive zone in the studied wells in the area and the most favorable areas for hydrocarbon accumulation are the northern and the south western parts of the study area. Abu Roash ”G” reservoir is considered as a non-productive zone, due to the sealing of the fault that control the major structural trap.