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Отправлено: 18.08.14 11:43. Заголовок: The Lamja sandstone in Northeast Nigeria: Sedimentology and reservoir quality
The Lamja sandstone in Northeast Nigeria: Sedimentology and reservoir quality Uzoegbu MU1* and Uchebo UA2 Department of Geology, University of Port Harcourt, PMB 5323, Port Harcourt, Nigeria. Tel: (+234) 08030715958; Abubakar Tafawa Balewa University, P.M.B 0248, Bauchi, Nigeria. The Lamja Sandstone conformably overlies the Numanha Shale. The exposures of the formation occur on the eastern and southern fringes of the Tertiary Lunguda Basalt Plateau. The Lamja Sandstone consists of shale, coal, siltstone, sandstone, sandy limsestone and carbonaceous sandstone. The dominant sedimentary structures are parallel lamination, cross bedding, cross lamination, cross stratification, planar bedding and bedding planes. Petrographic studies show that the sandstone is poorly-moderately sorted, very fine-fine grained and sub-angular-sub-rounded. Granolumetric data show a graphic mean size of 2.82©Є (fine grained sandstone), mean standard deviation of 1.62 (poorly sorted) while the skewness values are positively fine skewed, and kurtosis; showing an average value of 0.860 (mesokurtic). Bivariate plots standard deviation versus skewness, standard deviation versus mean; and standard deviation versus first percentile for sample studied cluster within the river environment. The cumulative probability curves plotted, showed that most of the samples are characteristics of fluvial. Keywords: Lamja sandstone, sedimentology, depositional environment, reservoir quality, poorly sorted. ................................................................... ¬Ј¬а¬д ¬Ј¬С¬Ю ¬Ъ ¬Я¬Ї¬Ъ¬Ф¬Ц¬в¬Ъ¬с!
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