Southeastern Onshore Tunisia
The Sidi Toui Block is located at the junction of the southern part of Jeffara Basin and the northern edge of Ghadames Basin.
The Jeffara Basin is part of the Paleozoic sag Basin and then evolved as a separate entity during the Carboniferous with a pronounced subsidence. During the Lower Paleozoic (Cambrian through Silurian), continental to marine clastic sedimentation were deposited in the area, including both some source rocks and reservoirs levels. The permo-carboniferous series, which is characterized by carbonate-dominated facies that unconformably overlies older sediments. This area was affected at the end of the Lower Paleozoic time by an intense folding followed by an erosion which generated the so-called “ Bou Nemcha high”
- Reservoirs and seals :
- The Ordovician Bir Ben Tartar sandstones are considered as the primary target in the block. This reservoir is producing oil in TT Oil Field located immediately south of the block. The intra- formational shales constitute an effective seals for this reservoir.
The Upper Silurian Acacus sandstones, only present south of the block are considered as secondary target with an Intraformational shales as an effective seals.
- The Upper Permian carbonates and the Cambrian Sidi Toui sandstones could be considered as additional targets in the block.
- Source Rocks
- The main source rock in the area is the Lower Silurian Tannezuft “hot shales”.
- Additional potential source rocks may be provided by Ordovician shales (Azel Equivalent in the Chotts Basin), and also by the carboniferous and the Upper Permian shales.
- The trapping system in the zone include tilted fault blocks and faulted anticlines