 Cuba has historically been dependent on oil imports.As of 2011, Cuba had proven reserves of a mere of crude oil and 2.5 trillion cubic feet of natural gas, and mostly used oil for power generation.In 2010, Cuba produced 51,000 barrels of crude oil a day (Kb/d) in 2010 in onshore or shallow near-shore development, "mostly heavy, sour (sulfur-rich) crude that requires advanced refining capacity to process."