URGENT: Chevron $CVX y other U.S. energy companies are close to an agreement to invest billions in Venezuela's oil fields

Chevron already operates three joint ventures with Venezuela's state oil company PDVSA and is close to adding two more heavy crude fields to its portfolio

Halliburton $HAL.US is also in talks, showing that the deal goes beyond crude ownership to include drilling work and infrastructure needed to restart production

The plan would lease specific fields to U.S. companies and send the oil they produce back to the U.S. market

Venezuela has the largest proven oil reserves in the world, bigger than those of Saudi Arabia, but years of underinvestment have left much of them undeveloped

Any production gains here would take years, since the old wells, pipelines, and export systems all need to be rebuilt first