That is not debt, it’s cost recovery which Exxon’s will recoup through their own production. So it’s in Exxon’s interest to harvest the oil to recoup their costs. Guyana owes them nothing unless Guyana cancel out.
Given the type of industry being spawned and the potential rewards, $1 bil is not that high a price. Bear in mind, this is all Exxon’s money invested, not Guyanese! Guyanese have virtually -0- capital at risk.