Just a week ago, ExxonMobil announced a huge new oil find at its Ranger-1 well, around 200 km offshore from Guyana.
That makes six big hits, starting with Liza-1 in May 2015. The first five totalled around 3.2 billion barrels.
Ranger-1 looks even bigger than its predecessors. So it's a fair bet we're talking at least four billion barrels of Guyanese reserves. And that's before ExxonMobil drills its next in line, the Pacora prospect—and a good few other wells planned for later in 2018.