ExxonMobil added 2.7 billion barrels of reserves in 2017

Image: CHARLY TRIBALLEAU / AFP / Getty Images

Breaking out of a debilitating two-year slump with spectacular discoveries in Guyana, ExxonMobil announced today that it added 2.7 billion barrels of proven oil and gas reserves in 2017, replacing 183% of its production.

Why it matters: The result is relief for ExxonMobil which, for decades the standard of Big Oil, has suffered black eye after black eye for performance failures, and begun being treated by Wall Street as a mere mortal on the oil patch.