%0 Journal Article
%T Hydrocarbons Migration through Groundwater Convergence toward Saline Depressions: A Case Study, Sidi El Hani Discharge Playa, Tunisian Sahel
%A Elhoucine Essefi
%A Mohamed Ali Tagorti
%A Jamel Touir
%A Chokri Yaich
%J ISRN Environmental Chemistry
%D 2013
%R 10.1155/2013/709190
%X This paper aims to provide proofs of hydrocarbons migration from petroleum reservoirs towards the surface of discharge playas. This is a case study of the discharge playa of Sidi El Hani, eastern Tunisia. The geochemistry of water of some hydrological drills in the Sahel area and of water from the discharge playa proves relatedness between the deep aquifer and the water of the discharge playa. Thus, the hydrology is now more than likely converging from the subsurface. This convergence may be an agent of transport of hydrocarbons. Concerning the organic matter within the discharge playa, high percentages of different fractions seem abnormal in such a saline context. This maturated organic matter should be viewed in the widest context of a multidisciplinary study taking into account the presence of petroleum potentials in the subsurface, the converging hydrogeology, and the tectonised region. The high percentage of Aromatic Polycyclic Hydrocarbon (APH) may be the result of hydrocarbons migration rather than anthropogenic pollution. As for the reinterpretation of previous works about the organic matter in playas done in sebkha Moknine, the contaminated organic matter, which was interpreted as a human induced activity, may have another origin from a reservoir located in the subsurface of the Sahel area. 1. Introduction Since the study of the petroleum system alone is not enough to achieve a more precise exploration, petroleum migration has recently become an important duty for petroleum exploration and assessment in petroleum basins (e.g., [1]). Over the last decades, several authors [2¨C7] have presented convincing evidences showing the integration of geological, geophysical, geochemical, hydrodynamic, and geothermal data as a powerful tool for understanding the relationships between groundwater and oil movement in sedimentary basins. As for the Tunisian context, some studies (e.g., [5, 8¨C16]) have revealed significant correlations between aquifers hydrodynamics and major conventional petroleum accumulations. Nevertheless, to satisfy this combination between the hydrogeological approach and the petroleum exploration, it is necessary first to prove the existence of a petroleum potential. Subsequently, the mechanism of migration of hydrocarbons by groundwater convergence may be discussed according to the geological context of the region. Concerning the case of the Tunisian Sahel, previous studies proved that these two conditions are quite satisfied. On the one hand, numerous geological studies and seismic investigations of the Sahel area have greatly
%U http://www.hindawi.com/journals/isrn.environmental.chemistry/2013/709190/