The geology of the Sudan (see The geology map of the Sudan )is extremely diverse with a variety of metamorphic, igneous and sedimentary rocks. Tow metamorphic belts have been recognized, these are:

· Orth – and Paragneisses of high grade ; old basement .
· Juvenile crust of green schist facis ; Pan African.

The intensity of deformation and metamorphism varies from place to place. Extensive studies were carried out by several workers, proved that the central Sudan and Nile Valley metamorphic belt include relic structures of ancient basement which date back to Lower Proterozoic or even Archaean.
The oldest sedimentary basins encountered so far in Sudan are of Cambro - Ordovician age? . These occur within narrow grabens formed by rifting, which preceded consolidation of Pan African structures in north and northwestern Sudan, ( The geology map of the Sudan ) shows the distribution of sedimentary basins in Sudan. Much attention has been given to an already explored Mesozoic rift related basin systems, in the south and central Sudan, while the Paleozoic basins in the NW Sudan have not been explored . Data from these basins such as surface geology, regional gravity and magnetic which indicate that the basins are deep and filled by thick pile of marine and continental sediments during Paleozoic and Mesozoic times e.g Murdi basin (4.5 km depth) , and South Wadi Howar basin (5 – 6 km) .
The gravity, seismic and drilling data acquired in interior Mesozoic basins in the central and southern Sudan indicated that more than 30000 feet of clastic sediments occur within the deepest central trough of the three major rift basins.
Fig(3), shows generalized stratigraphic columns for the Kaikang trough, which runs along the western flank of the Muglad basin and that of Unity in the Eastern flank, whereas, ---------Fig---------(4) shows the stratigraphy of the Melut basin.
The sediments are interbedded sandstones, claystones, siltstones , mudstones and shales. Intrusive rocks (Sills) were encountered in some wells such as in
Garad – 1, Sobat – 1, Tabaldi - 1…etc.
Changes in lithofacies primarly reflect variations in the subsidence rates of various sub-basins. The lack of significant magmatism during active rifting is attributed to the shallow depth of fault detachments at a brittle – ductile transition zone.
Abu Gabra Formation is the main source rock, consists of dark lacustrine shales containing a typically waxy kerogen and proved to be a reservoir in block # 6. Bentiu formation, Darfur group sandstone members, Amal and Tendi formations are the principal reservoirs. Shales and claystones within
Darfur Group as well as shales and claystones within Abu Gabra Formation act as seal to underlying oil bearing horizons.
None of the wells drilled in the Melut basin, has encountered the source rocks, however, based on the crude oil biomarker distributions and characteristics, it is believed that the source rock in Melut basin is equivalent to the Abu Gabra Formation found in the Muglad basin. Yabous Formation is the main reservoir in Melut basin.
Time of oil migration is uncertain, but it seems to be during mid to late Tertiary in the Muglad basin and during mid – Cretaceous to Late Cretaceous time in the Melut basin.
The present temperature gradients over these basins are normal and no over pressure zones have been recorded so far.