`The amount of accessible oil worldwide could eventually be increased by roughly 30 percent with the help of new drilling, imaging, and oil extraction technologies, including the use of microbes, say MIT researchers. Theoretically, this number could be even higher; in a best-case scenario, the amount of oil that could be produced would double.
On average, using current techniques, about two-thirds of the oil in an oil field gets left behind, says Richard Sears, a vice president at Shell International Exploration and Production, Houston, TX. “The fundamental problem is basic physics. It’s not like the oil is in big tanks. We produce oil from rock — sandstone. The oil is actually held in the very small spaces between the grains of sand. The problem is, when you try to move that oil out of the rocks, because of the size of the spaces, you end up with a layer of oil coating the insides of the rocks.” About one-third of the oil in fields will always be inaccessible. That leaves one-third that could be recovered with new technologies — which is equal to the amount that would have already been extracted.’