Northern Tunisia Thrust Belt – Deformation Model and Hydrocarbon Systems

Abstract

The integrated use of the geological, geophysical, and geochemical data of northern Tunisia onshore and offshore led to an inversion model from the Tethyan rifting and subsequent evolution of the North African passive margin to the Late Cretaceous–Tertiary orogeny, inducing the fold and thrust belt and associated foreland deformations. Respective deposits characterize each tectonic cycle; Triassic synrift and Jurassic–Cretaceous open-marine series are related to the Mesozoic opening, and Paleogene–Neogene clastic sequences are closely controlled by the Tertiary shortening. For hydrocarbon prospectivity and despite its early stage of exploration, this domain could be considered as an emerging area with encouraging ingredients, particularly three fractured carbonate reservoirs, two sandy reservoirs, five source rocks, and numerous potential structural and stratigraphic traps. The main feature in this area is the close relationship between the Tertiary tectonics and the evolution of the petroleum systems. Hence, the Numidian turbidites identified both as reservoir and source rock were deposited in a foredeep directly generated by the Paleogene thrusting and later displaced as far-traveled nappes above the Ypresian fractured limestones defined also as a source rock and reservoir. The maturity of these source rocks is closely related to the nappes displacement, which assumes the overburden and increases the heat flow. Fracturing is also generated by these events.