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A Subsurface Study on BED-1 and BED-4 Oil Fields, Abu El Gharadig Basin, Western Desert, Egypt, Based on Seismic and Well Logging Analyses

Lamees Mohamed

The main objective of this study is to shed more light and gain information on the geologic and tectonic setting of the area under study. This work also includes innovation approaches for interpretation and combination between seismic reflection and well logging data that directed mainly to subsurface structural setting and reservoir petrophysical characterization. In order to study the structures affecting Abu El Gharadig basin, four subsurface geological cross sections are constructed along four profiles extending W-E, NW-SE and SW-NE based on the available subsurface data gathered from the deep wells in the study area. These cross sections show that the studied area is affected by sets of normal faults. Most of these faults dissected the Cretaceous sequences and die out in Khoman Formation. New faults, however, affect Khoman and Apollonia formations. This indicates that the major tectonic movements, which affected Abu El Gharadig basin were took place near the Late Cretaceous. The Bahariya sandstone is subdivided from the reservoir point of view into three zones (Upper, Middle and Lower). The Bahariya is generally characterized by interbedded glauconitic shales, siltstones and sandstones. The sands appear to form thick and horizontally discontinuous bodies. The reservoir quality, distribution, continuity and thickness of the sands are best developed in the lower Bahariya zone and upper part of Kharita Formation which directly underlies Bahariya Formation. The mineral composition of the Bahariya sandstone is very complex due to the presence of heavy minerals such as sidrite. The presence of siderite, hematite, glauconite and pyrite resulted in low resistivity readings. The presence of glauconite in this formation shows high gamma ray readings which mask the clean sand. This problem appears in all the studied wells.

AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013