Stratigraphic Architecture of the Devonian Succession in Awaynat Wanin Area - Ghadamis Basin, Western Libya

During Palaeozoic times, the structuration of North Gondwana induced the formation of sub-basins separated by tectonic arches on the N orth African platforms. The slowly subsiding sub-basins were fed by periodically emerging and eroded arches (uplift vs eustatic sea-level drops) that control sediment distribution in space and time. The Devonian successions, located at the boundary between the Qarqaf arch and the subsiding Ghadamis basins in western Libya, represent a good record of this evolution and then an opportunity to discuss the relative influences of parameters that control the sequence architecture and reservoir distribution. The Devonian formations (Tadrart, Ouan Kasa, Awaynat Wanin, and Tahara Formations) in western Libya consist of more than 1000m of siliciclastic sediments. The succession is Pragian (Early Devonian) to Strunian (Late Devonian) in age and lies on Llandoverian (Early Silurian) shales along the Caledonian unconformity. These rocks are among the largest oil reservoirs in N orthern Africa. Most them are stratigraphic rather than structural traps and require detailed sedimentologic and stratigraphic works to improve the results of the exploration activities.This study based on outcrop and subsurface data respectively collected along the arch in Awaynat Wanin area and into the Ghadamis basin can provide some guidelines to fulfil this perspective.