Venturing into Unconventional Hydrocarbons Exploration: A case of the Albertine Graben in Uganda, East Africa
The Albertine Graben lies within the western arm of the East African Rift System. The graben has been the center of intensive exploration for conventional hydrocarbons during the past decade with over 20 oil and gas discoveries made to date at a success rate of over 90%. Data and samples collected from this exploration programs have provided insights into the potential for unconventional hydrocarbons in the graben. In this paper, data from surface field mapping, well data including core analysis, geochemical and 3D seismic collected from the graben has been used to demonstrate the possibility of potential unconventional hydrocarbon resources in Uganda. Some of the wells drilled in the Albertine Graben have penetrated substantially thick, thermally mature, low permeability, organic rich shale sequences which could be potential source rocks and reservoirs for unconventional hydrocarbons.
In some basins within the graben, well log interpretations show very high gamma and resistivity activity, and low bulk densities with variable gas/hydrocarbon accumulations. With some of the accumulations being observed within the shale sections. Analysis of oil shale samples from some of the drilled wells show that they are highly organic rich with TOC of up to 9%, mature, oil prone with unique mineralogy. Within the Albertine Graben therefore, despite the fact that these plays have not been given significant consideration in the recent past, evidence exists from surface studies, seismic and well data that point to potential for unconventional hydrocarbons. The country’s plan currently therefore is to carry out advanced studies on the thick shale sections to confirm their potential for shale gas reservoirs.
AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013