Geological mode and hydrocarbon accumulation mode in Muglad passive rift basin of Sudan

Muglad Basin in Sudan is a passive rift basin.It was resulted from the extensional tectonics of the dextral shear stress field in the shear zone of middle Africa.It is different from the active rift basin formed by the uplift of mantle convection.The multi-phase rifting and sagging cycles are obvious in the basin.In the vertical direction,there are three phases of rifts with the strong-weak-strong pattern,respectively.The geothermal gradient in Muglad Basin is lower than that in active rift basin and higher than that in cratonic basin.The main structure stale is half graben.In generally,the basin (mainly in Block 1/2/4) can be characterized by an uplift,two depressions and two slopes.The depressions and uplifts arranged in alternative pattern and have different characteristics in the east and the west parts.There developed many sets of oil source rocks.The Abu Gabra Formation generated in the first rift phase is the principle oil source bed in the basin.The assemblage of Bentiu reservoir rock and Aradeiba regional cap rock formed the chief oil-bearing beds.The tilted antithetic normal fault blocks are the main traps,where the enclose ability of the reservoir and the height of oil column were decided by the throw of the fault and lithology in both sides of the fault.The Muglad Basin has predominant hydrocarbon forming conditions and a great exploration potential.