History of hydrocarbon generation, migration and accumulation in the Fula sub-basin, Muglad Basin, Sudan: Implications of a 2D basin modeling study

Abstract

The Fula sub-basin is located in the northeastern part of the Muglad Basin. A 2D petroleum systems model of the Lower Cretaceous within the northern portion of the Fula Sub-basin was illustrated by integrating geological, geophysical and geochemical data. Timing of hydrocarbon generation, migration, and accumulation in the Fula Sub-basin are predicted from the model results. Based on reservoir distributions and common petroleum system events, the Fula Sub-basin petroleum system is considered to have three subsystems.In this petroleum system, deep lacustrine mudstones and shales in the Lower Cretaceous Abu Formation were known to be very good source rocks that possess more than 2.0 wt % TOC. Deltaic and turbidite sandstones within the Abu Gabra Formation and the thick fluvial sandstones of the upper Bentiu and fan-delta sandstones within the Aradeiba Formation are good reservoir bearing intervals. The mudstone in the Darfur Group acts as the regional seal. The petroleum system is considered to be effective and significant proportions of both oil and gas in these reservoirs can be preserved. The Abu Gabra Formation is considered to have entered the oil window approximately 120 Ma ago. Late oil generation continued for approximately 55 Ma. Gas generation took place in the mid-Eocene and probably continues to present-day. The results also show that the generated hydrocarbon is mainly oil with minor gas shows. In the main kitchen area, the migration and accumulation of hydrocarbon began at about 90 Ma. Migration is shown to be associated mainly with fault patterns controlling migration direction. Some migrated hydrocarbons escaped through the faults.