A 3d basin modelling approach to the assessment of hydrocarbon potential of Lake Edward basin, western Uganda

Abstract

Lake Edward basin is a rift basin located in the extreme south of the Ugandan portion of the western arm of the East African Rift System (EARS), popularly known as the Albertine Graben. 3D basin modelling approach was applied to Lake Edward basin with the objective of gaining an understanding of its hydrocarbon potential. The approach utilized 2D Seismic data, well data, geochemical data and well completion reports from Lake Edward basin. 2D seismic data were integrated with well log data to define stratigraphic framework of the basin, onto which heat flow and geochemical characterization was undertaken to establish the possible potential source rocks of the basin.

The integrated 3D basin modelling revealed the burial history, including the development of potential entrapment and source rock maturation. The major structures responsible for the hydrocarbon migration and entrapment in the field as interpreted are fault structures especially tilted faults blocks and normal faults. PetroMod software (version 2018.2) produced hydrocarbon maturation and generation model of the Lake Edward basin.

The model shows that the source rock, Lower Ngaji Formation is currently at temperatures between 50oC-80oC. According to the model, the source rock, Lower Ngaji with typical characteristics of a mixture of Type II and III kerogen is immature with respect to petroleum generation.

The research has provided a better understanding of key controls on hydrocarbon potential of Lake Edward basin and has enhanced the understanding of the timing and extent of hydrocarbon generation in Lake Edward basin and so the petroleum exploration risk can be potentially reduced This is useful for the oil and gas industry in the country as the findings are helpful in setting the next drilling phase of future exploration activities.