Petroleum Geologic Feature and Exploration Potential of Sufyan Depression,Muglad Basin

Sufyan Depression was a relatively independent depression,located in northwest of Muglad Basin,south of Sudan in Africa.With low exploration degree,there was still some controversy on basic petroleum geologic feature.The analysis shows that Sufyan Depression is a continental rift basin,developed during the Mesozoic-Cenozoic time under the dextral shears of the Central African Shear Zone.It can be divided into four structural units:south deep sag,center structural zone,north slope,northwest sag.Vertically,three sedimentary cycles are developed from Cretaceous to Quaternary.Lacustrine facies dark shale and claystone of Abu Gabra formation of early Cretaceous is main source rock with great oil-generating capacity.The development and evolution underwent three stages characterized by three-time rifting and sagging,which result in the formation of two assemblages of reservoir and seal in Cretaceous formation.Reservoir rock Bentiu sandstone and regional caprock Aradeiba claytone formed the best play in the whole area.Trap types are mainly faulted blocks,of which the tilted antithetic fault block is the most favorable to capture oil.Integrated study indicates that Sufyan Depression is of abundant hydrocarbon resources and has a great exploration potential.Central structural zone is the most favorable area for oil to accumulate and north slope is the second one.