Bentiu Fm

Muglad Basin -- SW Sudan and the northwestern part of South Sudan

Reference: Dou et al., 2023; Yagoub and Babiker, 2016

[Fig. 1: Western and Central African rift system. West African rift subsystem and Central African]

[Fig. 2: General stratigraphic column - Muglad Basin, Sudan, showing three geological cycles – Neocomian to Barremian, Aptian to Maastrichtian, and Paleocene to Pliocene - Miocene, or Quaternary and Petroleum Systems (from Ahmed and Ozumba, 2017)]

[Fig. 3: Comprehensive stratigraphic columns in the Muglad Basin (from Dou et al., 2023)]

[Fig. 4: Regional stratigraphy of the Muglad basin, SW Sudan (after Schull 1988; Dou Lirong et al. 2013 – extracted from Makeen et al., 2013)]

[Fig. 5: Location map of the Fula sub-basin in the Muglad basin including oilfields (study area) (after Dou Lirong et al. 2013 – extracted from Makeen et al., 2013)]

Medium to coarse-grained sandstone. The Bentiu Formation was deposited during a thermal subsidence stage when a set of fluvial sandstones developed in which thin layers of mudstone are intercalated (Dou et al., 2023). The upper section of Bentiu formation is sandstone and shale interbedded, and the lower section is considerably sandstone with interbedded shale (Yagoub and Babiker, 2016). Bentiu formation shows the maximum thickness in Rabah-1 well (886m) and minimum thickness Falah1 well (546m). But according to Jingyao (2015), the formation is about 1550m in thickness.

Ostracods (Babikir, 1997)

late Albian through early Cenomanian

Braided and meandering streams (Ramses, 1997). The massive unconsolidated and consolidated sands with low organic content suggest that deposition occurred in a relatively high energy fluviatile environment. The siltstones and claystones with high organic content and fresh water ostracods indicate a lacustrine environment (Babikir, 1997).