Another gem found while cleaning out my archives; note the date:
Of the estimated 3 trillion barrels of known oil throughout the world, 2 trillion barrels are considered unobtainable at today’s prices. “If we can increase recoverable oil by just 1 percent,” explains Brian Clark, head of Schlumberger-Doll laboratories, “that amounts to more than a year’s supply of oil for the whole world.”
–U.S. News & World Report, July 10, 1995, p.41, article on Schlumberger by Susan Headden.