Following are excerpts from two articles on oil and gas reserves in the United States of America from Science Magazine.
"... [A]fter considerable external review of the study, 'there has been no change in the numbers....'
"The recently released 1989 estimates ... are the lowest ever from Interior and fall within the range of recent private and industry estimates, which have been none too encouraging. The estimate of oil remaining to be found has plunged to only 35 billion barrels.
"If this estimate is correct, where does that put the United States? .... At the recent rate of consumption of 5.4 billion barrels per year, these reserves and the estimated undiscovered oil represent only a 16-year supply. With imports ... providing 50% of U.S. needs, as they do now, the domestic supply stretches to 32 years....
"Drawing more on natural gas might help, but the estimate of undiscovered gas did not fare any better. From the 594 trillion cubic feet estimated in 1981, undiscovered gas deposits are now believed to add up to only 263 trillion cubic feet. It was this drop in particular that upset Hodel, who saw gas looming large in America's energy future.... The bottom line? Counting an additional 306 trillion cubic feet of reserves, the United States would thus have a 35-year gas supply [at current consumption rates -- far less if we convert to natural gas in the transportation sector]."
Science, 22 September 1989, page 1330
"Like a prudent pensioner guaging what remains to support her in her later years, the United States periodically takes stock of how much oil and gas it has in the "bank." The government can't simply consult a ledger, however. It has to rely on innumberable geologic clues to guess at how much oil and gas is left to be found and extracted. But this guesswork, unlike a pensioner's bank account, can produce some happy surprises.
"... if intense, sophisticated drilling probes the fields' geologic nooks and crannies, the USGS estimates that they could yield another 60 billion barrels."
Science, 24 February 1995, page 1090