Central-western onshore Tunisia.
The Selja block is located in the Atlassic zone and includes the central and the southern portion of the Tunisian Atlas. It could be subdivided into two principles provinces:
- The Northern area is characterized by NE-SW trending fold belt being locally oriented NNE-SSW and E-W (Kasserine and Feriana areas).
- The southern area is dominated to the East by the structures related to the Gafsa Fault corridor(WNW-ESE)( Jbel Bouramli-Jbel Ben Younes) and by the structures related to deep – seated E-W strike slip faults in the North (Moulares area) and in the South (Metlaoui E-W ’’en echelon’’ folds).
These structures consist of an asymmetric anticlines made of Cretaceous sequence showing a steep to overturned SE/S flanks and separated by large and flat synclines with more or less thick Paleogene to Neogene continental to shallow marine series.
The area has recorded a multistage tectonic history that started by the Tethyan Rifting and continued until the Pliocene- Quaternary phases, which result in the current reliefs.
The block includes the Central and Southern portions of the Tunisian Atlas and is lying in proven hydrocarbon province; Douleb, Semmama and Tamesmida Fields in the Northern border, still producing oil from Aptian Carbonates, since 1968 and numerous other oil and gas fields located west of the permit in the Algerian side, and producing from Albian, Turonian and Coniacian carbonate reservoirs (Jebel Onk/Jebel Foua and Guerguit EL Kehal/Ras Toumb).
- Reservoirs and seals :
The Aptian Serdj dolomites and sandstones, the Upper Albian (Vraconian) F2B Carbonate Reservoir and the Jurassic lower and Upper Nara carbonates are the primary reservoirs in the block.
Lower Cretaceous Sidi Aïch, Boudinar and Meloussi sandstones are considered as potential reservoirs.
- Source Rocks
The Toarcian middle Nara black shales and the Upper Albian Fahdene organic-rich shales are the primary source rocks in the area.
The Upper Triassic (Carnian)locally organic-rich shales and carbonates are additional potential source rocks.
The Trapping system in the block includes faulted and tilted blocks and faulted anticlines.