Tullow Oil is to buy a half-share in five licences in the East African rift basins of Kenya and Ethiopia.Africa Oil Corp has sold Tullow 50% stakes in blocks 10BB, 10A, 12A and 13T in Kenya and the South Omo block in Ethiopia, an area covering 97,000 square kilometres.Under the terms of the agreements with Africa Oil Tullow will reimburse pro-rata past costs in each of these blocks and will carry Africa Oil for future net expenditures up to US$23.75m.The East African Rift Basin acreage shares many geological attributes with Tullow's Lake Albert rift basin position in Uganda but is some ten times larger, the company said. The acreage, which is located 500 kilometres to the east of Lake Albert, has good evidence of a live oil system. The Loperot-1 well drilled in 1992 recovered 29 degree API (American Petroleum Institute) waxy crude from Miocene sandstones, Tullow added. Seismic programmes are planned for the acreage in 2010 and 2011 and the first wells are expected to be drilled next year."Rift basins are a core play for Tullow and to date we have discovered and identified resources in excess of 2.5 billion barrels in the Lake Albert Rift Basin in Uganda," said Angus McCoss, exploration director of Tullow.