American motorists rely on Petróleos de Venezuela S.A. (PDVSA), one of the top exporters of oil to the US. The state-owned company is a global oil giant. It has proved reserves of more than 78 billion barrels of oil -- the most outside the Middle East -- and about 4.7 trillion cu. meters of natural gas. PDVSA's exploration and production take place in Venezuela, but the company also has refining and marketing operations in the Caribbean, Europe, and the US. Subsidiary CITGO Petroleum supplies gasoline to some 8,000 US retail outlets. PDVSA also makes Orimulsión, a heavy fuel alternative made from bitumen.