An unprecedented deal for the U.S. to gain access to a fifth of Venezuela's oil reserves - and the central role a Venezuelan businessman will play - is prompting questions and hesitation from some oil companies evaluating potential investments in the country, sources familiar with the situation told Reuters. A White House fact sheet released late on Monday outlined an arrangement under which private oil firm North American Blue Energy Partners (NABEP) would receive a 100-year lease for 17 oilfields in Venezuela holding some 65 billion barrels of oil reserves.