Standard Global Journal of Geology and Explorational Research (SGJGER)

001- 008

Authors: Marzouk Lazzez, Ramla Ben Rabah and Abdallah Maazaoui

In the Jeffara area, the Upper Jurassic M'rabtine member is constituted by platform carbonates interbedded with sand and shale. The sand levels form a good reservoir with a porosity of 17 % and a permeability of 130 md. The Lower Cretaceous reservoirs are hydrocarbon producer in the northeastern part of the Jeffara basin. Barremian sandstones (Sidi Aïch Fm.) have tested oil in some wells. Cenomanian Zebbag carbonates are hydrocarbon bearing in the Ezzaouia field and tested oil in El Bibane. The latter and also in some adjacent wells tested oil in the Aptian Orbata carbonates. Commonly, the Jeffara Basin has proven / moderate hydrocarbon play. In the central and northwest part of the basin, based on some control points, the area prospectivity is likely to moderate. Outcrop data as well as petrographical studies, tectono-stratigraphic overview and sedimentological investigation were used to exhibit exploration targets for hydrocarbons and form the proven reservoirs of significant oil-fields (e.g. Ezzaouia, El Bibane and Robbana). The Jaffara basin displays variety of siliciclastic and carbonate reservoirs, most likely extending from Ordovician to Cretaceous time. Source rock kitchens, regionally known within the Ordovician, Silurian, Carboniferous, Permian, Jurassic and Cretaceous successions, are locally deeply buried and fully mature in various parts of the basin. Traps are mainly structural; anticlines at Jurassic and Cretaceous level, forming the hydrocarbon pool in the Ezzaouia oil field. The siliciclastic deposits display substantial heterogeneity resulting from depositional environment and may hold basin-ward structural / stratigraphic traps. These lithofacies are showing hydrocarbon potential and could promote the poorly explored zone where locally several objectives within Jurassic and Cretaceous series are penetrated. Key words: Cretaceous, Jeffara Basin, wells tested, prospectivity