The Exploration History of the East Africa Rift System: A Tullow Oil Perspective

Cloke, Ian ¹
(1)Tullow Oil, London, United Kingdom.

The East African Rift System is now an exploration hotspot following the prolific exploration success of Tullow Oil and Heritage Oil in the Lake Albert Rift basin from 2006 to the present day. Conventional wisdom and paradigms have been challenged and overcome by the success in this basin and the question now asked by many is 'where is the next Lake Albert?'

Exploration in the East Africa Rift System is not new with oil seeps known for almost 100 years around Lake Albert and sampled by early field geologists mapping the African continent. The Tertiary rifts were tested by shallow wells in the 30's (Waki-1; Lake Albert) and 40's. Interest then waned until the 80's and 90's when the rifts were re-licensed. Amoco was a pioneer and jointly with Shell drilled a number of wildcat's with little success (Loperot-1 & Eliye Springs-1 Lake Turkana). It was only in the early 21st Century that interest re-turned to the rift's with Lake Albert being the focus for Heritage, Energy Africa and Hardman, now all acquired by Tullow Oil.

In excess of 1BBO has now been discovered in Lake Albert and the major >300MBO Jobi-Rii discovery in 2008-2009 was the largest discovery in onshore Sub-Saharan Africa for over 20 years. Significant resource potential still exists with the potential to easily double or triple the basin resource estimate. The record of 38 successes out of 39 drilled wells has highlighted the East Africa Rifts significant hydrocarbon potential if the golden thread linking source, reservoir, seal and trap can be identified. Where the independents once roamed alone the majors now follow and a number of keys wells will be drilled in differing Tertiary Rifts in 2011.

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