Back in the early 2000s, the outlook for energy security in the U.S. was bleak. Domestic oil production had been on a steady decline since 1985 and gas production was also well off its apex in the 1970s. M. King Hubbert’s concept of peak oil ignited fears of eventual energy scarcity. Given fossil fuels’ ubiquity underlying our entire Western economic and industrial structure, it’s no wonder that folks were concerned. But then the Shale Revolution changed everything. It’s often been said that necessity is the mother of invention and, after many trials and with considerable ingenuity, U.S. producers learned to wring massive volumes of previously trapped hydrocarbons from shale and gave the U.S. energy industry a new lease on life. But there are still limits on how much crude oil, natural gas and NGLs can be economically produced — and concerns lately that the best of the U.S.’s shale resources may have already been exploited. In today’s RBN blog, we examine crude oil and gas reserves: how they are estimated and what they tell us about the longevity of U.S. production.

