The Saudis want to keep the price of a barrel of oil between $70 and $80, because if it's much more than that, the incentives to finding alternatives to oil will be greater. And the Saudis don't want that!
"BIN TALAL: The stiff position of Saudi Arabia, we want the price to be between $70 and $80. Not only to help the West, but also to help ourselves. We don’t want the West to go and find alternatives, because, clearly, the higher the price oil goes, the more you have incentive to go and find alternatives. So, really, our interest coincides with American interest, to have the price for around $70, $80 which is a price good for consumers and producers."