--> Petroleum System Modeling and Exploration Potentiality in Abu Sufyan Sub-Baisn, Muglad Basin, the Republic of Suda

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Petroleum System Modeling and Exploration Potentiality in Abu Sufyan Sub-Baisn, Muglad Basin, the Republic of Suda

Abstract

Abstract

Abu Sufyan Sub-basin is located in the Northwest of Muglad Basin, the Republic of Sudan, which is an intra-Craton rift basin related to Central Africa Shear Zone. The hydrocarbon potentiality and favorable exploration trends are unclear due to complicate geological condition caused by the Central Africa Shear Zone. The geological models of stratigraphical framework, structure, sedimentary facies, source rock, reservoir rock and cap rock were built based on the available seismic data, well data, Rock-Eval data of shale cuttings and GC-MS analysis data of cutting and oil samples in the sub-basin and nearby area, and 1D/2D/3D petroleum system modeling were carried out and analyzed with IES PetroMod software. The study proved that the major source rock in the sub-basin was the lacustrine shale in AG formation formed during early Cretaceous, and mainly developed in the AG-2 and AG-4 sections. Three heat flow history scenarios, such as high, middle and low cases were assumed to model the hydrocarbon generation history due to the data limitation and uncertainty of the paleo-thermal history. The middle case of heat flow model, which was 35mW/m2 in early Cretaceous, 54mW/m2 in Paleocene, and 40mW/m2 in the present, was considered to be reasonable. The hydrocarbon generation and expulsion history modeling results indicated that the source rock in AG-4 section entered the oil window in the end of early Cretaceous, and the major expulsion period was late Cretaceous, while the source rock in AG-2 section entered the oil window in the end of late Cretaceous, and major expulsion period was Paleocene. The major migration pathway was from the western active source kitchens to the Central Structure Belt and the North Flank. Vertically, hydrocarbons were mainly accumulated in reservoir-cap assemblages under AG-2 and within AG-2 sections. There were two petroleum systems developed in the sub-basin, such as AG-2 and AG-4 systems. 43% volume of total resources generated from the source rock of AG-2 which mainly accumulated in within AG-2 assemblage, while 57% volume of total resources generated from the source rock of AG-4 which mainly accumulated under AG-2 assemblage. The favorable exploration trends are the Central Structure Belt and the North Flank, and the main targets should be reservoirs within AG-2 and under AG-2 assemblages.