Sedimentary facies analysis of the subsurface triassic and hydrocarbon potential in the United Arab Emirates
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The Triassic sediments in the subsurface of the United Arab Emirates has been divided into three formations (from bottom to top): Sudair, Jilh (Gulailah) and Minjur. The Sudair Formation consists of four lithofacies units composed mainly of limestones and minor dolomites interbedded with terrigenous shaley mudstones and anhydritic dolomitic limestones. These were deposited in shallow marine supratidal to subtidal settings. The Jilh (Gulailah) Formation has five lithofacies units dominated by anhydritic dolomitic limestone, fine terrigenoclastic sediments and bioclastic and intraclastic limestones. The formation was laid down under lagoonal to supratidal sabkha conditions with little normal marine influence. The Minjur Formation is composed of three lithofacies units characterized by argillaceous quartzitic sandstones, shales, mudstones, dolomitic and ferruginous limestones with thin coal seams. These facies represent deposition in prograding delta lobes, reflecting humid continental to marginal-marine conditions.
Diagenesis plays a major role in the reservoir development in the Triassic sediments, the pores are occluded by dolomite and anhydrite. The grains are compacted, leached or cemented by marine cements. Porosity generally ranges from fair to poor with values from 6% to 9% in the carbonates and from 6% to 15% in the clastics. Interparticle and vuggy porosities are the main pore types. The porosity was controlled by diagenesis, depth of burial and lithology.
No oil has been discovered so far in the Triassic sediments of the United Arab Emirates but pronounced gas shows have been reported from offshore fields. Western offshore United Arab Emirates is a promising area for potential hydrocarbon accumulations. The Triassic sediments have low to moderate source rock potential; the organic matter is mainly sapropelic kerogen, and the degree of thermal alteration ranges between mature to highly mature stages.
KeywordsSedimentary lithofacies Hydrocarbon Potential United Arab Emirates Triassic
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- Alsharhan, A.S. (1989): Petroleum Geology of the United Arab Emirates.—J. Petrol. Geol.,12, 253–288.Google Scholar
- Alsharhan, A.S. &Kendall, C.G.ST.C. (1986): Precambrian to Jurassic rocks of the Arabian Gulf and adjacent areas; their facies, depositional setting and hydrocarbon habitat.—Amer. Ass. Petrol. Geol. Bull.,70, 977–1002, TulsaGoogle Scholar
- Beydoun, Z.R. (1988): The Middle East: Regional Geology and petroleum Resources.—292 p. (Scientific Press)Google Scholar
- Buday, T. (1980): The regional geology of Iraq, v.1: Stratigraphy and paleogeography.—Baghdad, State Organization for Minerals, 445 p.Google Scholar
- Loutfi, G. & Sattar, A.M.M. (1987): Geology and hydrocarbon potential of the Triassic succession in Abu Dhabi, U.A.E.-Paper presented at the 5th Middle East Oil Show (Bahrain) March 9–12, 1987. SPE 15698, 717–735, BahrainGoogle Scholar
- Murris, R.J. (1980): Middle East: stratigraphic evolution and oil habitat.—Amer. Ass. Petrol. Geol. Bull.,64, 597–618, TulsaGoogle Scholar
- Powers, R.W. (1968): Arabie Saoudite (excluding Arabian Shield). —Lexique Stratigraphie Int., Centre Nat. Rech. Sci., Paris III, 177 p, ParisGoogle Scholar
- Powers, R.W., Ramirez, L.R., Redmond C.D. & Elberg, L.R. (1966): Sedimentary geology of Saudi Arabia.—In: Geology of the Arabian Peninsula.—US Geol. Surv., Prof. paper 560D, 150 p, Washington D.C.Google Scholar
- Sharief, F.A.M. (1982): Lithofacies distribution of the Permian-Triassic Period in the Middle East.—J. Petrol. Geol.,4, 299–310Google Scholar
- — (1983): Permian and Triassic geological history and tectonics of the Middle East.—J. Petrol. Geol.,6, 95–102Google Scholar
- Steineke, M., Bramkamp, R.A. & Sander, N.J. (1958): Stratigraphic relations of Arabian Jurassic oil.—In:Weeks L.G. (ed.): Habitat of Oil.—Amer. Ass. Petrol. Geol. Symposium, 1294–1329, TulsaGoogle Scholar
- Sugden, W. &Standring, A.J. (1975): Qatar Peninsula.—Lexique Stratigraphique Internat., Centre Nat. Rech. Scientifique, Paris, v.111, Asie, fasc. 10b3, 120 p, ParisGoogle Scholar
- United States Geological Survey-arabian American Oil Company (1963): Geologic Map of the Arabian Peninsula.—U.S. Geol. Survey, Misc. Geol Invest. Map 1–270 A, scale 1∶2,000,000, Washington D.C.Google Scholar