Speakers

Dozith Abeinomugisha

Dozith Abeinomugisha

Assistant Commissioner

Directorate of Petroleum, Ministry of Energy and Mineral Development, Uganda

Dozith Abeinomugisha is an Assistant Commissioner in the Directorate of Petroleum, Ministry of Energy and Mineral Development of the Uganda Government. He has worked for the Government of Uganda for the last 16 years in the oil and gas industry, having worked for 4 years in the mining sector.  Mr. Dozith Abeinomugisha obtained a Bachelor of Science Degree at Makerere University in Uganda and later obtained a Master of Science Degree in Petroleum Structural Geology from Royal Holloway College, University of London, in the United Kingdom. He has since obtained several certificates and Diplomas in Petroleum related disciplines. In addition to the Society of Petroleum Engineers, he is an Active member of the American Association of Petroleum Geologists (AAPG), a member of the Society of Exploration Geophysicists (SEG) and former President of the Geological Society of Uganda (GSU). He has authored several publications, reports and presentations. The latest being Chapter 9 of Memoir 100 of the American Association of Petroleum Geologists.


ABSTRACT

SESSION 4:  Transfer Zones in the Albertine Graben, East African Rift System, Uganda – Which type has been most successful?

The Albertine Graben forms the northernmost termination of the western arm of the East African Rift System. Rifting was initiated during the Miocene and thick sediments have accumulated in asymmetric basins along strike of the rift system. The rift is highly segmented and bordered by en–echelon linked border faults typically ten to twenty kilometers long. These faults are separated by transfer zones.

The Albertine Graben comprises a number of structural and topographic basins, lying in a general north-easterly trend in en–echelon pattern. These basins are shouldered to the east and west by Precambrian rocks, which are filled by sediments of Cenozoic age. The regional basement topography in the Albertine Graben as inferred from gravity and seismic data defines a series of depocentres, highs and fault systems. The depocentres are 5-6 km deep.

This rift has a number of transfer zones that include relay ramps and accommodation zones. The accommodation zones have been classified into two types namely; (i) the High Relief Extension Parallel and (ii) the Low Relief Oblique.

Accommodation Zone 1; the High Relief Extension Parallel occurs in the Semlik basin where the sharply upstanding mass of the Rwenzori Mountains lies centrally along the rift. Extension in this part of Albertine Graben is almost orthogonal leading to creation of linear and parallel fault systems.

Accommodation Zone 2 referred to as the Low Relief Oblique occurs in between Pakwach and Rhino Camp basins where there is a change in fault polarity. Mapping undertaken in this part of the Albertine Graben has pointed to oblique extension due to a change in stress application during Late Pleistocene.
On the other hand, relay ramps are a common feature formed during the growth of normal fault systems. Two synthetic fault segments create a dipping gap (in the past referred to as a fault bridge e.g Ramsay and Huber, 1987). This gap may be faulted by transverse faults leading to breaching; many times which enhances hydrocarbon migration.

In addition to the accommodation zones as areas of hydrocarbon importance in the Albertine Graben, we will discuss the role of fault spacing and relay ramps to the Petroleum System of this young rift. We will finally, point out the most successful transfer zones in terms of developed Petroleum Systems.