"The United States has an oil reserve at least three times that of Saudi Arabia locked in oil-shale deposits beneath federal land in Colorado, Utah and Wyoming, according to a study released yesterday. . . .
"For years, the industry and the government considered oil shale a rock that produces petroleum when heated too expensive to be a feasible source of oil.
"However, oil prices, which spiked above $70 a barrel this week, combined with advances in technology could soon make it possible to tap the estimated 500 billion to 1.1 trillion recoverable barrels, the report found."