Venezuela holds the world’s largest proven oil reserves, controlling more of the vitally important natural resource than any other nation, according to recent data.

Realizing President Donald Trump’s plan for a US-led revival of Venezuela’s beleaguered oil industry could be a years-long and challenging process costing upwards of $100 billion.

During a press conference Saturday at his Mar-a-Lago estate in Florida, Trump described an ambitious vision to use US financial resources and industry knowhow to restore the South American nation’s oi...