Squeezing More Oil from the Ground; October 2009; Scientific American Magazine; by Leonardo Maugeri; 8 Page(s)

On fourteen dry, flat square miles of California's Central Valley, more than 8,000 horsehead pumps—as old-fashioned oilmen call them—slowly rise and fall as they suck oil from underground. Glittering pipelines crossing the whole area suggest that the place is not merely a relic of the past. But even to an expert's eyes, Kern River Oil Field betrays no hint of the technological miracles that have enabled it to survive decades of dire predictions.

When Kern River Oil Field was discovered in 1899, analysts thought that only 10 percent of its unusually viscous crude could be recovered. In 1942, after more than four decades of modest production, the field was estimated to still hold 54 million barrels of recoverable oil, a fraction of the 278 million barrels already recovered. "In the next 44 years, it produced not 54 [million barrels] but 736 million barrels, and it had another 970 million barrels remaining," energy guru Morris Adelman noted in 1995. But even this estimate proved wrong. In November 2007 U.S. oil giant Chevron, by then the field's operator, announced that cumulative production had reached two billion barrels. Today Kern River still puts out nearly 80,000 barrels per day, and the state of California estimates its remaining reserves to be about 627 million barrels.