Method and system for heating a bed of rocks containing sulfur-rich type iis kerogen

Abstract

Hydrocarbon-containing rocks comprising type IIs kerogen are introduced into an excavated enclosure (e.g. a pit or an impoundment) to form a bed of rocks therein. One or more heaters (e.g. molten salt heaters) are operated to pyrolyze type IIs kerogen of the rocks. In some embodiments, a hydrocarbon reflux loop is maintained within the enclosure to convectively heat the type IIs-kerogen-containing rocks by boiling hydrocarbon liquids from a reservoir at the bottom of the enclosure so that vapor passes to the top of the enclosure, condenses, and falls back through the bed. Alternatively or additionally, the rocks may be heated by heaters embedded within wall(s) and/or a floor of the enclosure.

What is claimed is: 
     
         1 . A method of heating hydrocarbon-containing rocks comprising:
 a. introducing the hydrocarbon-containing rocks comprising sulfur-rich type IIs kerogen into an interior region of an excavated enclosure to form a bed of rocks therein;   b. maintaining a reservoir of hydrocarbon liquids substantially at the bottom of the interior region of the excavated enclosure; and   c. heating the hydrocarbon liquids of the reservoir so as to maintain a hydrocarbon reflux loop within the interior region to convectively heat the sulfur-rich type IIs kerogen of hydrocarbon-containing rocks.   
     
     
         2 . A method of heating hydrocarbon-containing rocks comprising:
 a. introducing the hydrocarbon-containing rocks comprising sulfur-rich type IIs kerogen into an excavated enclosure to form a bed of rocks therein;   b. heating the hydrocarbon-containing rocks sufficiently to significantly raise a temperature of a majority of the rock bed,   wherein for a substantial majority of horizontal locations of an upper half of the rock bed, sulfur-rich type IIs kerogen of the rocks id heated (i) primarily by heater(s) arranged substantially near a bottom of the enclosure and (ii) in a manner so that the dominant mechanism of transferring thermal energy thereto is downward convection.   
     
     
         3 . A method of thermally treating hydrocarbon-containing rocks comprising:
 a. introducing the hydrocarbon-containing rocks comprising sulfur-rich type IIs kerogen into an interior of an excavated enclosure to form a bed of rocks within an interior thereof;   b. heating the sulfur-rich type IIs kerogen of the containing rocks sufficiently to pyrolyze a majority of the sulfur-rich type IIs kerogen of the rock bed, wherein for a substantial majority of horizontal locations of an upper half of the rock bed, the dominant mechanism of heating of the rocks is heat convection by hot liquid hydrocarbons flowing through the rock bed.   
     
     
         4 . The method of any previous claim wherein the interior region is maintained under anoxic conditions during the heating. 
     
     
         5 . The method of any previous claim wherein sulfur-rich type IIs kerogen of the rocks id pyrolyzed, the hydrocarbon reflux loop supplying at least a portion of the thermal energy required to pyrolyze type IIs kerogen of the rocks. 
     
     
         6 . The method of any preceding claim wherein the reflux loop vertically spans at least a majority of the rock bed and/or of the interior region of the excavated enclosure. 
     
     
         7 . The method of any preceding claim wherein liquid hydrocarbon vapor of the reflux loop condenses primarily above the rock bed and/or substantially at a top thereof. 
     
     
         8 . The method of any preceding claim wherein a majority of the hydrocarbon fluid flow of the reflux loop passes via one or more vertical chimneys that substantially vertically traverse the rock bed. 
     
     
         9 . The method of  claim 8  wherein the vertical chimney passes through an interior of the rock bed. 
     
     
         10 . The method of any of  claims 8 - 9  wherein wall(s) of the vertical chimney are liquid-tight. 
     
     
         11 . The method of any of  claims 8 - 10  wherein wall(s) of the vertical chimney are heat conductors to facilitate conductive heat transfer from (i) hydrocarbon fluids migrating within the vertical chimney to (ii) rocks of the bed. 
     
     
         12 . The method of any previous claim wherein thermal energy supplied by the reflux loop is sufficient to significantly raise a temperature of at least one location at the top of the rock bed. 
     
     
         13 . The method of any previous claim wherein the heater(s) are immersed heaters located within a reservoir of hydrocarbon liquid. 
     
     
         14 . The method of any previous claim wherein the hydrocarbon liquid reservoir is located substantially at the bottom of the interior region of the excavated enclosure, the method further comprising: removing hydrocarbon liquids from the interior region of the enclosure at a rate which maintains a level of the reservoir above the heaters but substantially below the rock bed. 
     
     
         15 . The method of any previous claim wherein, the hydrocarbon-containing rocks are heated sufficiently to pyrolyze type IIs kerogen thereof into hydrocarbon pyrolysis liquids which (i) have a boiling point exceeding that of the reservoir and (ii) mix with the hydrocarbon liquids of the reservoir, wherein the method comprises in response to the mixing, regulating a boiling point of hydrocarbon liquids of the reservoir to prevent or limit an increase in a boiling point of the reservoir. 
     
     
         16 . The method of  claim 15  wherein the boiling point regulating comprises introducing relatively low-boiling point hydrocarbon condensable fluids into the interior of the enclosure to mix into the reservoir, a boiling point of the introduced fluids being significantly below that of the hydrocarbon pyrolysis liquids. 
     
     
         17 . The method of any of  claims 15 - 16  wherein the boiling point regulating comprises increasing a pressure within an interior of the excavated enclosure. 
     
     
         18 . The method of any previous claim wherein an atmospheric boiling point of the hydrocarbon liquids of the reservoir is maintained between 300 and 400 degrees Celsius. 
     
     
         19 . The method of any previous claim wherein the hydrocarbon liquid reservoir occupies at least 2.5% or at least 5% of a volume of the interior region of the excavated enclosure. 
     
     
         20 . A method of heating hydrocarbon-containing rocks comprising sulfur-rich type IIs kerogen within an excavated enclosure comprising:
 a. arranging the hydrocarbon-containing rocks comprising sulfur-rich type IIs kerogen into a rock bed within the enclosure so that one or more substantially vertical conduits substantially vertically traverse the rock bed;   b. respectively maintaining lower and upper hydrocarbon liquid reservoirs at upper and lower elevations, the lower elevation being substantially at the bottom of the enclosure and substantially below the rock bed, the upper elevation being above or substantially at the top of the rock bed,   wherein the upper hydrocarbon liquid reservoir is supplied primarily by boiling of hydrocarbon liquids of the lower reservoir so that vapors formed therefrom substantially vertically traverse the rock bed and condense into liquid of the upper reservoir, wherein at least some thermal energy for the pyrolysis is supplied by convective heat transfer from downward movement of hydrocarbon liquid through the rock bed from the upper reservoir to the lower reservoir.   
     
     
         21 . The method of  claim 20  wherein a floor of the upper reservoir includes a plurality of voids through which hydrocarbon liquids flow downwards into the hydrocarbon bed. 
     
     
         22 . The method of  claim 20  wherein the voids are distributed over the hydrocarbon bed so as to horizontally substantially evenly distribute downward liquid flow from the upper reservoir into the rock bed. 
     
     
         23 . The method of any previous claim, performed to pyrolyze sulfur-rich type IIs kerogen into a sulfur-rich pyrolysis liquid comprising at least 3% wt/wt or at least 4% wt/wt sulfur 
     
     
         24 . The method any previous claim, wherein a majority of pyrolysis of the sulfur-rich type IIs kerogen is performed at temperatures of at most 290 degrees Celsius. 
     
     
         25 . The method of any previous claim, wherein pyrolysis of the sulfur-rich type IIs kerogen generates an alkylthiophene-rich oil. 
     
     
         26 . The method of any previous claim, wherein pyrolysis of the sulfur-rich type IIs kerogen generates an alkylpyridine and/or alkylpyrrole rich oil. 
     
     
         27 . A system for hydrocarbon production comprising:
 a. a bed of rocks containing sulfur-rich type IIs kerogen, the rock being situated within the enclosure;   b. a hydrocarbon liquid reservoir located substantially at the bottom of the enclosure;   c. one or more immersed heaters situated within the liquid reservoir; and   d. one or more substantially-vertical chimney(s) that substantially vertically traverse the bed of rocks,   the system configured so that the immersed heaters convectively heat rocks of the rock bed by a hydrocarbon reflux loop passing through the chimney(s) and through the bed of rocks.   
     
     
         28 . The system of  claim 27  wherein an interior of the enclosure is substantially oxygen free. 
     
     
         29 . A system for production of hydrocarbon fluids, the system comprising:
 a. an excavated enclosure defining an interior region bounded by a plurality of enclosing surfaces including wall(s) and a floor;   b. rocks containing sulfur-rich type IIs, the rocks being arranged within the interior region of the excavated enclosure to form a rock bed therein;   c. external heater(s) configured to heat the rocks of the rock bed within the enclosure primarily by externally heating the enclosing surfaces so that thermal energy is transferred from the heated enclosing surface(s) to the rocks of the rock bed.   
     
     
         30 . A system for production of hydrocarbon fluids, the system comprising:
 a. an excavated enclosure defining an interior region bounded by a plurality of enclosing surfaces including wall(s) and a floor;   b. rocks containing sulfur-rich type IIs kerogen, the rocks arranged within the interior region of the excavated enclosure to form a rock bed therein;   c. wall-embedded or floor embedded heater(s) embedded within at least one wall(s) or floor and configured to heat the rocks of the rock bed within the enclosure primarily by externally heating the wall or floor so that thermal energy is transferred from the heated wall or floor to the rocks of the rock bed.   
     
     
         31 . The system of any of  claims 29 - 30  wherein the wall-embedded heater primarily heat the wall or floor by radiantly heating an external, outward-facing surface thereof. 
     
     
         32 . The system of any of  claims 29 - 30  wherein the embedded heater is deployed within a wall-chamber or floor-chamber that is fluid-sealed from the interior region. 
     
     
         33 . The system of any of  claims 29 - 30  wherein a majority of the wall-chamber or floor-chamber of the wall or floor is occupied by heaters. 
     
     
         34 . The system of any of  claims 29 - 30  wherein an inner space within the heater wall(s) or floor is substantially filled with a granular material and/or within low molecular-weight gas. 
     
     
         35 . The system of any of  claims 29 - 30  wherein the heater comprises heater conduits having an outer surface that is roughened and blackened to increase emissivity. 
     
     
         36 . The system of any of  claims 29 - 30  wherein at least one of the walls is horizontally supported by an interior side of the pit or by earth of an impoundment to maintain a structural integrity of the interior region wall. 
     
     
         37 . A system for production of hydrocarbon fluids, the system comprising:
 a. an excavated enclosure defining an interior region bounded by a plurality of enclosing surfaces including wall(s) and a floor;   b. an interior wall sub-dividing the interior region into first and second sub-regions;   b. rocks containing sulfur-rich type IIs kerogen, the rocks respectively arranged within each of the sub-regions to respectively form a first and second rock beds therein;   c. a wall-embedded heater embedded within the interior wall and configured to respectively and simultaneously heat opposite side of the interior wall so as to simultaneously heat both the first and second rock-beds.   
     
     
         38 . The system of  claim 37  wherein the wall-embedded heater is located within an interior cavity of the inner wall, the interior cavity being sealed from both sub-regions. 
     
     
         39 . The system of  claim 37  wherein a reservoir of liquid is located within an inner cavity of the interior wall, and the wall-embedded heater(s) is configured to boil liquid of the reservoir so that vapor formed therefrom convectively transfers thermal energy to both sides of the interior wall. 
     
     
         40 . The system of any of  claims 25 - 39  wherein:
 i. at least one of the enclosing surfaces is a interior-facing surface of a heat-conducting place comprising interior-facing and exterior-facing surfaces; and 
 ii. the system is configured so that radiant-heat transfer from the external heater(s) to the exterior-facing surface significantly contributes to the heating of the interior-facing surface of the heat-conducting plate. 
 
     
     
         41 . The system of  claim 40  wherein radiant-heat transfer from the external heater(s) to the exterior-facing surface contributes a majority of the thermal energy used to heat the interior-facing surface of the heat-conducting plate. 
     
     
         42 . The system of any of  claims 25 - 41  wherein an interior of the enclosure is substantially oxygen-free. 
     
     
         43 . The system of any of  claims 25 - 42  wherein one or more of the walls of the enclosure are substantially uniformly heated to a temperature of at least 300 degrees Celsius, or at least 350 degrees Celsius, or at least 400 degrees Celsius. 
     
     
         44 . The system of any of  claims 25 - 43  wherein the rocks are heated primarily by heat transferred from the combination of all wall(s) and the floor of the enclosure. 
     
     
         45 . The system of any of  claims 25 - 44  wherein the system is configured so that operation of the heater(s) delivers sufficient thermal energy to the rock bed to pyrolyze at least a majority of kerogen therein. 
     
     
         46 . The system of any of  claims 25 - 45  wherein a primary mechanism of heat transfer is the combination of conduction and radiation from the heated enclosing surface(s). 
     
     
         47 . The system of any of  claims 25 - 46  wherein at least one of the heater(s) is an external convection heater. 
     
     
         48 . The system of  claim 47  wherein the convection heater is a molten salt heater. 
     
     
         49 . The system of any previous claim further comprising an external liquid reservoir outside of the interior region of the enclosure, at least one of the external heater(s) being immersed within the external liquid of the external reservoir and operated to boil the external liquid to transfer thermal energy to at least one wall of the enclosure. 
     
     
         50 . A system for production of hydrocarbon fluids, the system comprising:
 a. an excavated enclosure defining an interior region bounded by a plurality of enclosing surfaces including wall(s) and a floor,;   b. rocks containing sulfur-rich type IIs kerogen, the rocks arranged within the interior region of the excavated enclosure to form a rock bed therein;   c. an external liquid reservoir located outside of the interior region the enclosure; and   d. at least one external heater immersed within the reservoir configured to boil liquid of the reservoir so that vapor formed therefrom convectively transfers thermal energy to one or more the enclosure walls so as to heat the rock bed.   
     
     
         51 . The system of  claim 50  wherein the external heater is a molten salt heater. 
     
     
         52 . The system of  claim 51  wherein an elevation of the external liquid reservoir is substantially that of the floor of the interior region. 
     
     
         53 . The system of any of  claims 49 - 50  configured to substantially uniformly heat a wall of the enclosure. 
     
     
         50 . A system for production of hydrocarbon fluids, the system comprising:
 a. an enclosure;   b. rocks containing sulfur-rich type IIs kerogen, the rocks arranged within the enclosure to form a bed of rocks therein;   c. a quantity of hot molten salt;   d. molten salt circulation apparatus configured to force the quantity of hot molten salt to flow through one or more conduit(s) in thermal communication with the rock bed so as to heat the rock bet.   
     
     
         55 . The system of claim  54  wherein at least some of the conduit(s) pass through a portion of the packed bed. 
     
     
         56 . The system of any of claims  54 - 55  wherein at least some of the conduit(s) are located substantially at a floor or wall(s) of the enclosure. 
     
     
         57 . A system for hydrocarbon production comprising:
 a. a substantially sealed enclosure;   b. a bed of containing sulfur-rich type IIs kerogen, the bed of rocks being situated within the enclosure and supported by a grating support which elevates the packed bed above a floor of the enclosure to define a lower section of the enclosure below the packed bed;   c. a hydrocarbon liquid reservoir within the lower section of the enclosure; and   d. one or more immersed heaters situated within the liquid reservoir and configured to heat the kerogen-containing rocks by means of thermal convection.   
     
     
         58 . The system of  claim 57  wherein an interior of the enclosure is substantially oxygen free. 
     
     
         59 . The system of any of  claims 57 - 58  further comprising: e. one or more substantially-vertical chimneys within the sealed enclosure(s), the chimney having a lower opening that is substantially below the rock bed and an upper opening situated above the rock bed or substantially at an upper level thereof. 
     
     
         60 . The system of any of  claims 53 - 58 , further comprising one or more spreader trays located above the rock bed or substantially at a top of the rock bed. 
     
     
         61 . The system or method of any previous claim wherein one or more of the heaters is a molten salt heater. 
     
     
         62 . The system or method of any previous claim wherein a volume of the interior region and/or a volume of the rock bed is at least 1,000 meters 3 , or at least 2,500 meters 3 , or at least 5,000 meters 3 , or at least 10,000 meters 3 , or at least 25,000 meters 3 . 
     
     
         64 . The system or method of any previous claim wherein a height of the rock bed is at least 5 meters or at least 10 meters or at least 20 meters or at least 30 meters or at least 50 meters. 
     
     
         65 . The system or method of any previous claim wherein the excavated enclosure is a pit or an impoundment. 
     
     
         66 . The system of method of any previous claim wherein the rock bed occupies at least a majority, or at least a substantial majority of the interior region of the enclosure. 
     
     
         67 . The system of method of any previous claim wherein a volume of the interior region of the enclosure and/or a volume of the rock bed is at least 1,000 meters 3 , or at least 2,500 meters 3 , or at least 5,000 meters 3 , or at least 10,000 meters 3 , or at least 25,000 meters 3 . 
     
     
         68 . The system of method of any of previous claim wherein at least one of the walls is horizontally supported by an interior side of the pit or by earth of an impoundment to maintain a structural integrity of the interior region wall. 
     
     
         69 . Use of the system of any of  claims 27 - 68  to pyrolyze sulfur-rich type IIs kerogen into a sulfur-rich pyrolysis liquid comprising at least 3% wt/wt or at least 4% wt/wt sulfur 
     
     
         70 . Use of the system of any of  claims 27 - 68  to pyrolyze sulfur-rich type IIs kerogen, wherein a majority of pyrolysis of the sulfur-rich type IIs kerogen is performed at temperatures of at most 290 degrees Celsius. 
     
     
         71 . Use of the system of any of  claims 27 - 68  to pyrolyze sulfur-rich type IIs kerogen so as to generate an alkylthiophene-rich oil. 
     
     
         72 . Use of the system of any of  claims 27 - 68  to pyrolyze sulfur-rich type IIs kerogen so as to generate an alkylpyridine and/or alkylpyrrole rich oil 
     
     
         73 . The method of any previous claim or the use of the system of any previous claim so as to pyrolyze sulfur-rich type IIs kerogen so as to generate an oil wherein a ratio between respective concentrations of alkylthiophenes and alkyldibenzothiophenes in the oil is at least 10 or at least 15 or at least 20 or at least 30. 
     
     
         74 . The method of any previous claim or the use of the system of any previous claim so as to pyrolyze sulfur-rich type IIs kerogen so as to generate an oil wherein a majority of alkylthiophenes of the oil are thiophene C 4 H 4 S or C1-C4 alkylthiophenes. 
     
     
         76 . The method of any previous claim or the use of the system of any previous claim so as to pyrolyze sulfur-rich type IIs kerogen so as to generate an oil wherein a majority of alkylthiophenes of the oil are thiophene C1-C4 alkylthiophenes. 
     
     
         77 . The method of any previous claim or the use of the system of any previous claim so as to pyrolyze sulfur-rich type IIs kerogen so as to generate an oil wherein a majority of alkylthiophenes of the oil are thiophene C1-C3 alkylthiophenes. 
     
     
         78 . The method of any previous claim or the use of the system of any previous claim so as to pyrolyze sulfur-rich type IIs kerogen so as to generate an oil wherein a majority of alkylthiophenes of the oil are thiophene C2-C3 alkylthiophenes.