Patent ID: 6880633

Claim:
A method of treating an oil shale formation in situ, comprising: providing heat from one or more heat sources to at least a part of the formation; allowing the heat to transfer from the one or more heat sources to a selected section of the formation; controlling the heat from the one or more heat sources such that an average temperature in at least a majority of the selected section of the formation is less than about 370° C. such that production of a substantial amount of hydrocarbons having carbon numbers greater than 25 is inhibited; controlling a pressure in at least a majority of the selected section of the formation, wherein the controlled pressure is at least 2.0 bars; and producing a mixture from the formation, wherein about 0.1% by weight of the produced mixture to about 15% by weight of the produced mixture are olefins, and wherein an average carbon number of the produced mixture is greater than 1 and less than about 25.