Method of recovering hydrocarbons from carbonate and shale formations

Abstract

A method to mobilize for production bitumen, kerogen, heavy oil, other hydrocarbons, and hydrogen contained in a subterranean formation comprised largely of silicate and carbonate minerals that are capable of generating a series of chemical reactions, that once induced are self-sustaining. Such formations include bitumen carbonates, unconventional oil or gas shales and oil shales. The induced silicate-reactions, carbonate-reactions and resulting hydrocarbon-reactions and heat generated in the formation are sufficient to chemically and physically decompose much of the rock structure so that it becomes porous and permeable. These reactions also convert the solid bitumen, heavy oil, kerogen and other hydrocarbons to fluid or gaseous forms and create formation fluids and reservoir pressure to help move hydrocarbons to production wells. Waste heat generated by the method may be used to generate electricity, or for other uses.

1 . A method of mobilizing and recovering hydrocarbons from a subterranean formation comprising hydrocarbons, silicate minerals and carbonate minerals, comprising the steps of:
 (a) providing an injection well and a production well extending into the formation;   (b) injecting carbon dioxide and heat under pressure through the injection well into the formation sufficient to cause
 (i) chemical reactions whereby carbon dioxide decomposes silicate minerals, producing heat, 
 (ii) chemical reactions whereby heat decomposes carbonate minerals, producing carbon dioxide, and 
 (iii) heating of hydrocarbons, giving them greater fluidity; 
   (c) allowing the effects (i), (ii) and (iii) of step (b) to spread into the formation around the injection location and decompose silicate minerals and carbonate minerals in the formation creating in those areas a more permeable structure and hydrocarbons with greater fluidity;   (d) ceasing the injection of heat and carbon dioxide into the formation when the effects (i), (ii) and (iii) of step (b) have spread into the formation and the chemical reactions that decompose the silicate minerals and the carbonate minerals become self-sustaining; and   (e) recovering resulting formation fluids comprising fluid and gaseous hydrocarbons from the production well.   
     
     
         2 . A method according to  claim 1 , wherein, in step (b), the step of injecting heat through the injection well comprises heating a fluid or gas and injecting the hot fluid or gas through the injection well. 
     
     
         3 . A method according to  claim 2 , wherein the hot fluid comprises carbon dioxide. 
     
     
         4 . A method according to  claim 1 , wherein, in step (b), the step of injecting heat through the injection well comprises injecting a combustible fuel through the injection well and igniting the combustible fuel. 
     
     
         5 . A method according to  claim 1 , wherein, in step (b), the step of injecting heat through the injection well comprises injecting a fluid or gas down the injection well through or close by a down hole heater. 
     
     
         6 . A method according to  claim 1 , further comprising, in step (b), injecting steam into the formation materials. 
     
     
         7 . A method according to  claim 1 , further comprising extracting heat from the formation and delivering it to the ground surface. 
     
     
         8 . A method according to  claim 7 , wherein said step of extracting heat from the formation is continued after ceasing step (e). 
     
     
         9 . A method according to  claim 1 , further comprising providing a heat energy extraction system having a wellbore extending into the formation, and extracting heat energy from the formation using the heat energy extraction system. 
     
     
         10 . A method according to  claim 1 , further comprising recovering produced fluid or gaseous hydrocarbons from the injection well. 
     
     
         11 . A method according to  claim 1 , further comprising recovering heat energy from the produced formation fluids. 
     
     
         12 . A method according to  claim 1 , wherein the produced formation fluids further comprise carbon dioxide, and the method further comprising separating and compressing the carbon dioxide. 
     
     
         13 . A method according to  claim 12 , further comprising sequestering the separated carbon dioxide. 
     
     
         14 . A method according to  claim 1 , wherein the produced formation fluids further comprise greenhouse gases other than carbon dioxide, and the method further comprises separating, compressing and sequestering said greenhouse gases. 
     
     
         15 . A method according to  claim 1 , wherein a portion of the formation contains insufficient carbonate minerals for the chemical reactions that decompose the silicate minerals to be self-sustaining throughout the formation, and the method further comprises using the existing injection well, or providing a second injection well into that portion of the formation, and injecting carbon dioxide under pressure into that portion of the formation, continuing to do so until sufficient carbonate minerals are available such that the chemical reactions that decompose the silicate minerals and the carbonate minerals become self-sustaining. 
     
     
         16 . A method according to  claim 1 , wherein a portion of the formation contains insufficient silicate minerals for the chemical reactions that decompose the carbonate minerals to be self-sustaining throughout the formation, and the method further comprises using the existing injection well, or providing a second injection well into that portion of the formation, and injecting heat under pressure into that portion of the formation, continuing to do so until sufficient silicate minerals are available such that the chemical reactions that decompose the silicate minerals and the carbonate minerals become self-sustaining. 
     
     
         17 . A method according to  claim 1 , further comprising suppressing the chemical reactions that decompose the carbonate minerals and the silicate minerals in at least a portion of the formation. 
     
     
         18 . A method according to  claim 17 , wherein the suppressing is done by means of (i) injecting a gas other than carbon dioxide into the formation, (ii) injecting a cold liquid into the formation, or (iii) reducing the pressure in the formation. 
     
     
         19 . A method according to  claim 1 , wherein the production well includes a generally horizontal portion in the formation 
     
     
         20 . A method according to  claim 1 , wherein the production well includes a generally vertical portion in the formation. 
     
     
         21 . A method of mobilizing and recovering hydrocarbons from a subterranean formation comprising hydrocarbons, silicate minerals and carbonate minerals, comprising the steps of:
 (a) providing an injection well and a production well extending into the formation;   (b) fracturing a portion of the formation to form a region of fractured formation materials in fluid communication with the injection well;   (c) injecting carbon dioxide and heat under pressure through the injection well into the region of fractured formation materials sufficient to cause
 (i) chemical reactions whereby carbon dioxide decomposes silicate minerals, producing heat, 
 (ii) chemical reactions whereby heat decomposes carbonate minerals, producing carbon dioxide, and 
 (iii) heating of hydrocarbons, giving them greater fluidity; 
   (d) allowing the effects (i), (ii) and (iii) of step (c) to spread into the formation around the region of fractured formation materials and decompose silicate minerals and carbonate minerals in the formation creating in those areas a more permeable structure and hydrocarbons with greater fluidity;   (e) ceasing the injection of heat and carbon dioxide into the region of fractured formation materials when the effects (i), (ii) and (iii) of step (c) have spread into the formation around the region of fractured formation materials and the chemical reactions that decompose the silicate minerals and the carbonate minerals become self-sustaining; and   (f) recovering resulting formation fluids comprising fluid and gaseous hydrocarbons from the production well.   
     
     
         22 . A method according to  claim 21 , wherein, in step (c), the step of injecting heat through the injection well comprises heating a fluid or gas and injecting the hot fluid or gas through the injection well. 
     
     
         23 . A method according to  claim 22 , wherein the hot fluid comprises carbon dioxide. 
     
     
         24 . A method according to  claim 21 , wherein, in step (c), the step of injecting heat through the injection well comprises injecting a combustible fuel through the injection well and igniting the combustible fuel. 
     
     
         25 . A method according to  claim 21  wherein, in step (c), the step of injecting heat through the injection well comprises injecting a fluid or gas down the injection well through or close by a down hole heater. 
     
     
         26 . A method according to  claim 21  further comprising, in step (c), injecting steam into the region of fractured formation materials. 
     
     
         27 . A method according to  claim 21 , further comprising, in step (b), fracturing a portion of the formation to form a region of fractured formation materials in fluid communication with the production well. 
     
     
         28 . A method according to  claim 21 , further comprising, in step (b), fracturing a portion of the formation to form a region of fractured formation materials in fluid communication with both the injection well and the production well. 
     
     
         29 . A method according to  claim 21 , further comprising extracting heat from the formation and delivering it to the ground surface. 
     
     
         30 . A method according to  claim 29 , wherein said step of extracting heat from the formation is continued after ceasing step (f). 
     
     
         31 . A method according to  claim 21 , further comprising providing a heat energy extraction system having a wellbore extending into the formation, and extracting heat energy from the formation using the heat energy extraction system. 
     
     
         32 . A method according to  claim 21 , further comprising recovering produced fluid hydrocarbons from the injection well. 
     
     
         33 . A method according to  claim 21 , further comprising recovering heat energy from the produced formation fluids. 
     
     
         34 . A method according to  claim 21 , wherein the produced formation fluids further comprise carbon dioxide, and the method further comprising separating and compressing the carbon dioxide. 
     
     
         35 . A method according to  claim 34 , further comprising sequestering the separated carbon dioxide. 
     
     
         36 . A method according to  claim 21 , wherein the produced formation fluids further comprise greenhouse gases other than carbon dioxide, and the method further comprises separating, compressing and sequestering said greenhouse gases. 
     
     
         37 . A method according to  claim 21 , wherein a portion of the formation contains insufficient carbonate minerals for the chemical reactions that decompose the carbonate minerals to be self-sustaining throughout the formation, and the method further comprises providing a second injection well and injecting carbon dioxide under pressure through the second injection well into the formation. 
     
     
         38 . A method according to  claim 21 , wherein a portion of the formation contains insufficient silicate minerals for the chemical reactions that decompose the silicate minerals to be self-sustaining throughout the formation, and the method further comprises providing a second injection well and injecting heat through the second injection well into the formation. 
     
     
         39 . A method according to  claim 21 , further comprising suppressing the chemical reactions that decompose the carbonate minerals and the silicate minerals in at least a portion of the formation. 
     
     
         40 . A method according to  claim 39 , wherein the suppressing is done by means of (i) injecting a gas other than carbon dioxide into the formation, (ii) injecting a cold liquid into the formation, or (iii) reducing the pressure in the formation. 
     
     
         41 . A method according to  claim 21 , wherein the production well includes a generally horizontal portion in the formation. 
     
     
         42 . A method according to  claim 21 , wherein the production well includes a generally vertical portion in the formation. 
     
     
         43 . A method according to  claim 21 , wherein the hydrocarbons comprise heavy hydrocarbons. 
     
     
         44 . A method according to  claim 1 , wherein the hydrocarbons comprise kerogen. 
     
     
         45 . A method according to  claim 1 , wherein the injection well and the production well are one and the same well, extending into the formation.