Subsurface heater

Abstract

In one aspect, the present invention provides a subsurface heater comprising: a combustible gas supply conduit; an oxygen supply conduit and a heat transmissive external housing encompassing a porous refractory medium. The combustible gas supply conduit and the oxygen supply conduit are configured as a concentric pair disposed within the porous refractory medium and coupled to a plurality of gas jets disposed within the porous refractory medium. The porous refractory medium has disposed within it a plurality of combustion product gas return conduits. The combustion product gas return conduits are configured to receive combustion product gases from the porous refractory medium. Also provided in another aspect of the present invention, is a method for heating a subsurface zone.

1 . A subsurface heater comprising:
 a combustible gas supply conduit and an oxygen supply conduit configured as a concentric pair disposed within a porous refractory medium and coupled to a plurality of gas jets disposed within the porous refractory medium, the porous refractory medium having disposed within it a plurality of combustion product gas return conduits, the combustion product gas return conduits being configured to receive combustion product gases from the porous refractory medium; and a heat transmissive external housing encompassing the porous refractory medium.   
     
     
         2 . The subsurface heater according to  claim 1 , wherein the porous refractory medium is at least one selected from the group consisting of alumina, silica, zirconia, silicon carbide, alumina-silicon dioxide, zirconia-alumina composites, and metals balls including metals such as iron, or iron based alloys. 
     
     
         3 . The subsurface heater according to  claim 1 , wherein the porous refractory medium is selected from the group consisting of alumina, silica, carbon and silt. 
     
     
         4 . The subsurface heater according to  claim 1 , wherein the gas jets precess about a central axis defined by the gas supply conduits. 
     
     
         5 . The subsurface heater according to  claim 1 , wherein the gas jets are independently operable. 
     
     
         6 . The subsurface heater according to  claim 1 , wherein the combustion product gas return conduits are symmetrically disposed within the porous refractory medium. 
     
     
         7 . The subsurface heater according to  claim 1 , wherein the combustion product gas return conduits are located on the periphery of the porous refractory medium and adjacent to an inner surface of the heat transmissive external housing. 
     
     
         8 . The subsurface heater according to  claim 1 , wherein the combustion product gas return conduits are independently operable. 
     
     
         9 . The subsurface heater according to  claim 1 , further comprising a plurality of temperature sensors. 
     
     
         10 . The subsurface heater according to  claim 9 , wherein the temperature sensors are configured to provide data to a control system. 
     
     
         11 . The subsurface heater according to  claim 1 , wherein the combustion product gas return conduits are spaced in a cluster in the porous refractory medium. 
     
     
         12 . A method for heating a subsurface zone, comprising:
 (a) creating an accommodation cavity for a subsurface heater comprising a combustible gas supply conduit and an oxygen supply conduit configured as a concentric pair disposed within a porous refractory medium and coupled to a plurality of gas jets disposed within the porous refractory medium, the porous refractory medium having disposed within it a plurality of combustion product gas return conduits, the combustion product gas return conduits being configured to receive combustion product gases from the porous refractory medium; and a heat transmissive external housing encompassing the porous refractory medium;   (b) installing the subsurface heater; and   (c) operating the subsurface heater.   
     
     
         13 . The method according to  claim 1 , wherein the combustible product gas is at least one selected from the group consisting of nitrogen, oxygen, carbon dioxide, and water vapor. 
     
     
         14 . The method according to  claim 1 , wherein the accommodation cavity is created in a hydrocarbon reservoir. 
     
     
         15 . The method according to  claim 1 , wherein the accommodation cavity is created in a near-surface zone. 
     
     
         16 . A subsurface heater comprising:
 a combustible gas supply conduit and an oxygen supply conduit configured as a concentric pair disposed within a porous refractory medium and coupled to a plurality of gas jets disposed within the porous refractory medium, the porous refractory medium having disposed within it a plurality of combustion product gas return conduits, the combustion product gas return conduits being configured to receive combustion product gases from the porous refractory medium; and a heat transmissive external housing encompassing the porous refractory medium and wherein the plurality of gas jets are independently operable.   
     
     
         17 . The subsurface heater according to  claim 16 , wherein the porous refractory medium is at least one selected from the group consisting of alumina, silica, zirconia, silicon carbide, alumina-silicon dioxide, zirconia-alumina composites, and metals balls including metals such as iron, or iron based alloys. 
     
     
         18 . The subsurface heater according to  claim 16 , wherein the gas jets precess about a central axis defined by the gas supply conduits. 
     
     
         19 . The subsurface heater according to  claim 16 , further comprising a plurality of temperature sensors configured to provide data to a control system. 
     
     
         20 . The subsurface heater according to  claim 16 , wherein the combustion product gas return conduits are located on the periphery of the porous refractory medium and adjacent to an inner surface of the heat transmissive external housing.