|UGANDA EXPLORATION: AN OVERVIEW|
|Exploration Hot Spots|
1Tullow Oil Plc
This is the history of a frontier basin located in the Western arm of the East Africa Rift system in the Great Lakes area of Central Africa (Figure 1), that although known to contain oil seeps from the early 20th century has in the last few years delivered over 1BBO of resources in over 20 discoveries. This is the story of the Lake Albert Rift Basin and Tullow’s prolific exploration success from 2005 to the present day. In 1992 Energy Africa evaluated a farm-in to the then Fina held concession’s covering both the DRC and Ugandan side of Lake Albert but it was not until 2001 that Energy Africa farmed into the Heritage Oil operated Exploration Area 3 and entered Exploration Area 2 together with Hardman Oil & Gas. Energy Africa was in turn acquired by Tullow Oil in 2004 who then subsequently acquired Hardman Oil and Gas, our partner in Exploration Area 2. Tullow then entered EA1 in joint partnership with Heritage Oil. Tullow therefore had access to a regional understanding and database of the entire 200km long and 45km wide Lake Albert Rift.
A regionally based scientific approach supported by satellite mapping, gravity, full tensor gradiometry, 2D and 3D seismic and detailed fieldwork has under-pinned Tullow’s success. Early indications from outcrop and seep sampling and basin modeling demonstrated the presence of a world class source rock of Miocene to Pliocene age that was in the oil maturity window in the sub-surface. The question that was still un-resolved was were there seals, reservoirs and traps in the sub-surface.
The Mputa oil discovery was made in 2005 and un-locked the rift flank play. It was swiftly followed by the Waraga, Nzizi and Kingfisher discoveries all made in 2006. These discoveries were in themselves in-sufficient to commercialize the basin. Having established the petroleum system worked attention shifted to the northern end of the Lake Albert rift where Tullow acquired over 2700km of 2D seismic data in varied seismic campaigns from 2007-2008. The Butiaba wildcat campaign commenced in April 2008 with the Taitai oil and gas discovery over 80km from the nearest well penetration. The Victoria Nile Delta play was then tested at Kasamene-1. (Figure 3) resulting in the discovery of excellent quality fluvial reservoirs in a tilted fault block sealed by world-class lacustrine shales. Tullow then committed major capital expenditure to the Uganda business unit and launched a drill-out campaign following a ‘golden thread’ that resulted in 15 further discoveries in the play including the major Buffalo-Giraffe, Ngiri, Nsoga and Kasamene discoveries (Figure 3), all amplitude supported. In 2010 Tullow reached 1BBO (Figure 4) of discovered resources in the basin. Upside continues to be discovered as evidenced by more recent well results within the play.
The next phase of the basin development has now commenced with the re-alignment of interests in the three exploration licenses following the sale of Heritage Uganda to Tullow Oil Uganda and the subsequent farmdown of 33.3% interest to Total and 33.3% interest to Cnooc to prepare for a world class development capable of producing in excess of 200kbopd, delivering oil to an in-country refinery and exporting the remainder by pipeline to the Indian ocean. Tullow has had the patience and perseverance to build a regional position in a now perceived prolific East African rift basin. A collaborative team approach to playmaking, prospecting and well picking resulted in an exploration campaign that delivered over 20 discoveries in 5 years resulting in the discovery of in excess of 1BBO. This success story will truly change and is changing Uganda and East Africa.
It is a story of a successful independent explorer, challenging existing paradigms, overcoming significant challenges, discovering a completely new basin and changing the economies of an entire region.