The country with the largest crude oil reserves in the world is:

Venezuela has the largest proven oil reserves in the world, estimated at 303 billion barrels, mostly found in the Orinoco Belt. This reserve constitutes about 17% of the total global reserves, exceeding the reserves of Saudi Arabia (267-297 billion barrels) and Canada (168 billion barrels). Venezuela has the largest reserves but faces challenges in extracting oil due to the heavy and dense nature of the oil.