Abstract: The invention is a method of fracturing an underground formation penetrated by a wellbore, which comprises injecting into a formation a mixture of carbon dioxide and a polar alcohol or polar glycol additive at a temperature and pressure above the critical temperature and pressure of carbon dioxide. The alcohol or glycol additive should have less than about 9 carbon atoms and comprises about 0.1% to about 10% by weight of the injected mixture. The mixture is injected with sufficient volume and pressure to cause a fracture to be formed in the underground formation.

Abstract: The invention is a method of recovering hydrocarbons from underground hydrcarbon formations by injecting a mixture of carbon dioxide and a polar alcohol or polar glycol additive, said additive having less than about 9 carbon atoms. The mixture of carbon dioxide and additive is injected at a temperature and pressure above the critical temperature and pressure of carbon dioxide. The alcohol or glycol additive comprises about 0.1% to about 10% by weight of the injected mixture. After being injected through an injection well, the mixture is driven through the formation and the hydrocarbons and other fluids are recovered at one or more production wells.