The Influences of Climate and Water-Level Changes on the Evolution of Sequence Stratigraphy and Sedimentary System of the Lower Cretaceous, in the Fula Sag, Muglad Basin, Sudan

Sequence stratigraphic and sedimentologic theories and methods were employed in the study of sequence stratigraphic features and sedimentary system distributions in the Cretaceous of the Jake oil field in Fula sag,Muglad Basin,Sudan.Data gathered through core,drilling and logging and seismic events,were resorted to establish sequence stratigraphic framework,determine the types and distribution of sedimentary facies and understand evolution pattern and controlling factors in Lower Cretaceous.The Cretaceous can be described as three second-order sequences, and Lower Cretaceous can be divided into seven three-order sequences.The result shows that sedimentary facies including fan delta,submarine fan,braided river deltas and rivers deposits were recognized in the Lower Cretaceous.Depositional facies varied vertically from fan delta to submarine fan and then to braided river delta in Abu Gabra Formation, and from braided river to meandering river and then to delta in the Bentiu Formation.The distribution of the sediments is controlled by multi-factors in Jake oil field. Vertically, tectonic activity is the main factor which control the facies change in Abu Gabra. However, climate change and coast recession mainly affect the facies distribution. Horizontally,sediment supply and local subsidence differences controlled the distribution of sand body.