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EL-DAIRY, M., Sagazig University of Egypt, no city listed, Egypt, and J. M. PEREZ* and J. M. POSTON, Texas A&M University, College Station, TX

ABSTRACT: Petrophysical Analysis of Sandstones Using CT Scanning and Conventional Methods

Computer assisted tomography (CT) scanning, standard thin section, electron microscopy (EM), micromorphology, x-ray diffraction (XRD), and grain size mechanical analyses were combined to study Paleozoic sandstone rocks. The samples investigated are oil reservoir and aquifer formations in the Gulf of Suez hydrocarbon province at the southern part of Sinai in Egypt. Samples were collected from three exposures: (1) at the East Gebel Musabaa Salama, (2) west-central Sinai at Wadi Soal, and (3) Wadi Dahab located in the eastern part of the Gulf of Aquaba region.

The study correlates results obtained from the mentioned conventional analyses to CT results. The obtained correlations attempted to demonstrate that some of the expensive and time consuming conventional analyses can be substituted by this rapid and inexpensive imaging technique. Results indicate that CT images yield two important parameters: (1) mean value of CT numbers (CTm) over a given area of the obtained images, and (2) standard deviation of CT numbers (CTs) within the selected part of the images.

CTm numbers are directly correlated to grain density, and CTs values give a quantitative value that represents the degree of heterogeneity-homogeneity of the rock. An accurate analysis of rock samples can be obtained by a fast study of these two parameters. CTs values were used to determine depositional environments of the studied rocks. This classification was later confirmed using grain-size statistical parameters.

Classification of rock samples using CT scanning also detected difficult-to-note properties, such as the presence of formation fines. Furthermore, we also discuss the roles of bulk and grain densities, amount of formation fines or clay content, pore geometry, and porosity.

AAPG Search and Discovery Article #90989©1993 GCAGS and Gulf Coast SEPM 43rd Annual Meeting, Shreveport, Louisiana, October 20-22, 1993.