In situ thermal processing of an oil shale formation using conductive heating

Abstract

Methods and systems of treating an oil shale formation using an in situ thermal process are described herein. A method of treating an oil shale formation in situ includes providing heat from one or more heat sources to at least a portion of the formation; allowing the heat to transfer from at least the portion to a selected section of the formation substantially by conduction of heat; pyrolyzing at least some hydrocarbons within the selected section of the formation; and producing a mixture from the formation.

1 - 410 . (canceled) 
     
     
         411 . A method of treating a relatively low permeability formation containing heavy hydrocarbons in situ, comprising:
 providing heat from one or more heat sources to at least a portion of the formation;   allowing the heat to transfer from at least the portion to a selected section of the formation substantially by conduction of heat;   pyrolyzing at least some hydrocarbons within the selected section of the formation; and   producing a mixture from the formation.   
     
     
         412 . The method of  claim 411 , wherein the one or more heat sources comprise at least two heat sources, and wherein superposition of heat from at least the two heat sources pyrolyzes at least some hydrocarbons within the selected section of the formation. 
     
     
         413 . The method of  claim 411 , wherein the one or more heat sources comprise electrical heaters. 
     
     
         414 . The method of  claim 411 , further comprising controlling a pressure and a temperature within at least a majority of the selected section of the formation, wherein the pressure is controlled as a function of temperature, or the temperature is controlled as a function of pressure. 
     
     
         415 . The method of  claim 411 , further comprising controlling the heat such that an average heating rate of the selected section is less than about 1.0° C. per day during pyrolysis. 
     
     
         416 . The method of  claim 411 , wherein the produced mixture comprises condensable hydrocarbons having an API gravity of at least about 25°. 
     
     
         417 . The method of  claim 411 , wherein the produced mixture comprises condensable hydrocarbons, and wherein about 0.1% by weight to about 15% by weight of the condensable hydrocarbons are olefins. 
     
     
         418 . The method of  claim 411 , wherein the produced mixture comprises non-condensable hydrocarbons, and wherein a molar ratio of ethene to ethane in the non-condensable hydrocarbons ranges from about 0.001 to about 0.15. 
     
     
         419 . The method of  claim 411 , wherein the produced mixture comprises condensable hydrocarbons, and wherein less than about 1% by weight, when calculated on an atomic basis, of the condensable hydrocarbons is sulfur. 
     
     
         420 . The method of  claim 411 , wherein the produced mixture comprises condensable hydrocarbons, and wherein greater than about 20% by weight of the condensable hydrocarbons are aromatic compounds. 
     
     
         421 . The method of  claim 411 , wherein the produced mixture comprises condensable hydrocarbons, and wherein less than about 0.3% by weight of the condensable hydrocarbons are asphaltenes. 
     
     
         422 . The method of  claim 411 , wherein the produced mixture comprises condensable hydrocarbons, and wherein about 5% by weight to about 30% by weight of the condensable hydrocarbons are cycloalkanes. 
     
     
         423 . The method of  claim 411 , wherein the produced mixture comprises a non-condensable component, wherein the non-condensable component comprises hydrogen, wherein the hydrogen is greater than about 10% by volume of the non-condensable component, and wherein the hydrogen is less than about 80% by volume of the non-condensable component. 
     
     
         424 . The method of  claim 411 , further comprising controlling a pressure within at least a majority of the selected section of the formation, wherein the controlled pressure is at least about 2.0 bars absolute. 
     
     
         425 . The method of  claim 411 , further comprising controlling formation conditions to produce a mixture of condensable hydrocarbons and H 2 , wherein a partial pressure of H 2  within the mixture is greater than about 0.5 bars. 
     
     
         426 . The method of  claim 411 , further comprising altering a pressure within the formation to inhibit production of hydrocarbons from the formation having carbon numbers greater than about 25. 
     
     
         427 . The method of  claim 411 , wherein controlling formation conditions comprises recirculating a portion of hydrogen from the mixture into the formation. 
     
     
         428 . The method of  claim 411 , further comprising:
 providing hydrogen (H 2 ) to the heated section to hydrogenate hydrocarbons within the section; and   heating a portion of the section with heat from hydrogenation.   
     
     
         429 . The method of  claim 411 , wherein the produced mixture comprises hydrogen and condensable hydrocarbons, the method further comprising hydrogenating a portion of the produced condensable hydrocarbons with at least a portion of the produced hydrogen. 
     
     
         430 . The method of  claim 411 , wherein producing the mixture comprises producing the mixture in a production well, and wherein at least about 7 heat sources are disposed in the formation for each production well.