SUBSURFACE STRUCTURAL AND PETROPHYSICAL STUDY ON KARAMA FIELD, EAST BAHARIYA CONCESSION, WESTERN DESERT, EGYPT.

Document Type : Original Article

Authors

1 Geology Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.

2 Geology Department, Faculty of Science, Al-Azhar University (Assiut branch), Assiut, Egypt.

3 TPS Lead Geologist and Business Development Manager, Cairo, Egypt.

4 Baker Hughes Company, Cairo, Egypt.

Abstract

Geophysical information in the form of seismic and well logging data are used to understand the structural elements, tectonic setting, stratigraphy and petrophysical  characteristics of the upper Cretaceous rock units (Bahariya, Abu Roash and Khoman Formations) in the Karama field, northern part of the Western Desert. The interpretation of the available seismic data led to the identification of the reflectors under investigation as well as to map and determine the structural elements on the tops of the evaluated lithostratigraphic units. Seismic lines were used to make Four Two Way Time (TWT) structural contour map, reflection and four depth maps on the top of Khoman, Abu Roash "A", Abu Roash "G" and Upper Bahariya Formations reflecting the occurrence of major 11 normal faults in various directions (mainly NW-SE) forming different types of horst and graben structures. The structure of Karama-2 to Karama-4 wells is a stretched shoestring/oval shape E-W dipping against the dipping fault "F1", the resulting fold axis; however, is ENE-WSW with downthrown toward the southern part of the study area. The wire line log interpretations in 6 wells distributed in the study area have been used to evaluate the petrophysical parameters of the Abu Roash "G" Member, which is considered as an important reservoir in the study area. Computer-assisted log analyses have been used to evaluate all petrophysical interpretation such as effective porosity (ΦE), water saturation (Sw), hydrocarbon saturation (Sh). Horizontal distributions in forms of contour maps were constructed using computer software. Some vertical sections have been illustrated using IP (Interactive Petrophysics) program software output in order to show the vertical and lateral variations in reservoirs characteristics.  The average values of effective porosity recorded among the studied wells range from 13% to 25% in the southern area toward the northeastern part of the study area. The shale volume generally is ranging from 24% at the southern part to 2% at the northeastern part of the area. The sand thickness of the net pay is ranging from 7% at the southern part to 25% at the eastern part of the study area.

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Al-Azhar Bulletin of Science
Volume 22, Issue 2-D
December 2011
Pages 61-79

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