BUSINESS Big Oil could see proven reserves run out in less than 15 years as output is not replaced by discoveries May 13, 2021 OSLO — The proven oil and gas reserves of the group of major companies called “Big Oil” are falling at an alarming rate, as produced volumes are not being fully replaced with new discoveries. A Rystad Energy analysis shows that Big Oil lost 15% of its stock levels in the ground last year, with remaining reserves set to run out in less than 15 years — unless the group makes more commercial discoveries, and fast. The task is becoming more and more challenging as investments in exploration shrink and success rates slump. The declining proven reserves could create serious challenges for Big Oil (ExxonMobil, BP, Shell, Chevron, Total and Eni) to maintain stable production levels in coming years.