The Ogaden basin is one of the largest sedimentary basins in east Africa. It is also the largest basin in Ethiopia which covers an area of 350,000 km2. Since the middle of the last century hydrocarbon exploration studies have been carried out in the basin the Calub formation and the Adigrat sandstone are identified to be the reservoir rocks of the most Calub wells. Although enough studies has not been conducted in the reservoir rocks, to assess the potentiality of the reservoir rocks this paper is focused on the determination of the observable porosity using petrographic methods and the estimation of the permeability and the hydrocarbon saturations using well logging data. The used core samples were from calub-4, calub-5, calub-7 and calub-9 wells from different intervals. A total of 24 core-cutting samples (Calub-4; six samples, Calub-5; six samples, Calub-7; six samples and Calub-9; six samples) were carefully chosen and the same number of thin sections were prepared from the core-cutting samples. The whole thin section samples collected from the laboratory were subjected to petrographic analysis and it was later interpreted. The maximum porosity and permeability observed in the reservoir Adigrat sandstone of Calub-4, Calub-5, Calub-7 and Calub-9 was 12.6% and 97.2x10-3µm2 respectively while the minimum porosity and permeability observed was 3.5% and 0.1x10-3µm2 respectively. The maximum porosity and permeability observed in the reservoir Calub sandstone of Calub-4, Calub-5, Calub-7 and Calub-9 were 11.3% and 18.5x10-3µm2 respectively as the minimum porosity and permeability observed was 2.2% and 0.1x10-3µm2 respectively. In conclusion it can be said that the Adigrat and Calub formations are highly hydrocarbon potential reservoirs. ORCID NO: 0000-0003-3953-781X, 0000-0002-1290-749X
Anahtar Kelimeler: Ogaden Basin, Adigrat Sandstone, Calub Formation, Reservoir rock properties
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