" it could go where it did have some expertise—in shale—and see if it could extract oil from the dense rock as it did natural gas. But that would push Papa into a position similar to that faced by George Mitchell—climbing up a high wall of skepticism. “Industry dogma,” in EOG’s words, flatly asserted that shale rock was too dense, even with fracturing, for oil to flow. According to that dogma, oil molecules were much larger than gas molecules, and thus would not be able to fit through the tiny pores that fracking would create in the rock. "

― Daniel Yergin , The New Map: Energy, Climate, and the Clash of Nations