科研之友
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摘要
Bahariya Formation sandstones represent important Cretaceous oil and gas reservoirs for Egypt. The formation has been investigated by innumerable well logging activities. The previous focus of petrophysical research has been on Bahariya Oasis where the formation is exposed at the surface and serves as the type locality.
In this study, over one hundred core samples from a deep borehole located in the Abu Gharadig Basin within the Western Desert of Egypt have been investigated. From the 35 m thick section where samples have been taken, several logging curves were available to enable a complex core-log data comparison.
Owing to a conspicuous flaser bedding of these sandstones, an anisotropy effect was expected. Samples were collected in two different orientations for each sampling depth: perpendicular and parallel to foliation. From the core, the degree of anisotropy was determined for electrical resistivity, gas permeability, p-wave velocity and thermal conductivity. A novel definition of the coefficient of anisotropy of permeability is presented. Using this definition, the degree of anisotropy of electrical and hydraulic conductivity becomes comparable. Fractures in the direction of the flasered structures cause an increased horizontal permeability and consequently a considerable anisotropy. The anisotropy of p-wave velocity is less sensitive to the flasered structures.
- 出版日期2009-12
