Advancements in the Understanding of the Regional Geology and Hydrocarbon Prospectivity of the Lake Edward Area of Uganda and Democratic Republic of Congo

Bain, Ronald ¹; Nicholas, Chris ²; Copestake, Philip ³
(1)Dominion Petroleum Ltd., London, United Kingdom. (2) Trinity College, Dublin, Ireland. (3) Merlin Energy Resources Ltd, Ledbury, United Kingdom.

Following the drilling of the Ngaji-1 exploratory well in 2010 in Uganda Exploration Block 4B (EB4B), Dominion Petroleum continued its technical assessment program of EB4B and the adjacent Exploration Block 5, Democratic Republic of Congo (DRCB5), the latter in conjunction with the operator, SOCO. Although the Ngaji-1 well did not encounter hydrocarbons, it did confirm the presence of multiple high quality reservoirs within the objective Plio-Pleistocene interval. Lack of any hydrocarbon accumulation in the well has been attributed to the absence of effective source rock within the migration fetch area defined by the localized structural elements.

Gravity data suggest the presence of a very large, four-way dip-closed feature west of the Ngaji-1 well that could represent both a barrier to hydrocarbon migration into the drilled structure as well as a highly attractive exploration prospect with the confirmation of a likely kitchen west of, and immediately adjacent to, the structural feature. Based upon post-drill analyses of all currently available data, the geologic model envisioned for this overall area of Lake Edward is that of the Overfilled Lake Basin. This model would explain the lack of hydrocarbons in the Ngaji-1 well and is consistent with the presence of the structural high as described.

The additional technical assessment consists of integration of the Ngaji-1 well results with a freshly re-processed version of the existing 2D dataset, AVO modeling derived from the well log data, the acquisition of an additional ~500 km of new seismic across both EB4B and DRCB5 and regional integration of the seismic and well data with gravity data across both blocks. As appropriate, other supporting analyses such as basin modeling will be undertaken as well. All aspects of the additional technical evaluation program are expected to be completed in 2011.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.