Sequence Stratigraphy and Sedimentary Facies of Fula Subbasin, Muglad Basin (Sudan)

Abstract

Sedimentary analysis and Facies Associations may enhance accuracy of sequence stratigraphic correlation of Fula Subbasin, Muglad Basin, Sudan. According to core (very little) and log data, stratigraphic correlation was set. Abu Gabra Formation, Bentiu Formation, and Aradeiba Formation were subdivided into units. Essential depositional systems were recognized in the study area on the basis of the evolution of sedimentary facies. The origin of Fula Subbasin is related to the first rifting cycle (+ synrifting cycle?) that took place during the Early Cretaceous associated with an increase in tectonic activity and the opening of the Central African rift system (Late Jurassic- Middle Miocene). Synsedimentary tectonic activity and succeeding restructural regime of the subbasin were clearly reflected in the sedimentary records. Two sets of faulting in Fula oil field were detected. The first set was striking NW-SE, as in five zones the Fula 1 fault, Fula 2 fault, Fula 3 fault, eastern fault of well Fula 1 and the western fault of well Fula North 2, which dominate the evolution and sediments of the Fula structure. The second set was striking EW, as the north fault of well Fula 1, which controls the evolution of the trap. Three seismic horizons, i.e. the top of Aradeiba, the top of Bentiu and the top of Abu Gabra formations were chosen for interpretation according to their geological significance. Infill of that Early Cretaceous subbasin began with continental deposits that were alluvial and lacustrine in origin.