Systems and methods for low emission hydrocarbon recovery

Abstract

Systems and methods are provided for low emission (in-situ) heavy oil production, using a compound heat medium, comprising products of combustion of a fuel mixture with an oxidant and a moderator, mixed with steam generated from direct contact of hot combustion products with water, under pressure. The compound heat medium, comprising mainly CO 2 and steam, is injected at pressure into a hydrocarbon reservoir, where steam condenses out of the compound heat medium releasing heat to the reservoir. The condensate is produced with the hydrocarbon as a hydrocarbon/water mixture or emulsion. Non-condensable gases, primarily CO 2 , from the compound heat medium may remain in the reservoir through void replacement, leakage to adjacent geological strata. Beneficially, any CO 2 produced is recovered at pressure, for use in other processes, or for disposal by sequestration. Produced water is recovered and recycled as a moderator and steam generating medium.

1 . A method of extracting a hydrocarbon from a hydrocarbon bearing matrix material comprising the steps of:
 (a) generating a compound heat medium comprising fuel combustion products, carbon dioxide and steam at elevated temperature and pressure by steps of:   in a first stage combusting a fuel in the presence of an oxidant and a moderator to create products of combustion at an elevated temperature and pressure comprising carbon dioxide;   in a second stage contacting a steam generating medium with said products of combustion at elevated temperature and pressure, to generate steam;   (b) delivering the compound heat medium at pressure to the hydrocarbon bearing matrix material thereby condensing steam and heating and mobilizing a portion of hydrocarbons;   (c) recovering under pressure a mobilized portion comprising hydrocarbons and carbon dioxide, and separating pressurized carbon dioxide from the mobilized portion.   
     
     
         2 . A method according to  claim 1 , wherein in the second stage, contacting the steam generating medium with said products of combustion comprises injecting the steam generating medium, evaporating a portion of the steam generating medium to form steam, and accumulating a reservoir of unevaporated steam generating medium. 
     
     
         3 . A method according to  claim 2 , comprising delivering a portion of the accumulated steam generating medium to the combustor to provide a portion of the moderator. 
     
     
         4 . A method according to  claim 3 , wherein the moderator comprises combustibles that are combusted in the first stage. 
     
     
         5 . A method according to  claim 3 , wherein the moderator comprises non-combustible solids. 
     
     
         6 . A method according to  claim 1  wherein the mobilized portion comprises aqueous condensate, and further comprising recovering said aqueous condensate from the mobilized portion. 
     
     
         7 . A method according to  claim 1 , wherein the steam portion of the compound heat medium comprises saturated steam. 
     
     
         8 . A method according to  claim 6  wherein at least a portion of the aqueous condensate is recovered to provide a portion of at least one of the moderator and the steam generation medium. 
     
     
         9 . A method according to  claim 2 , wherein the mobilized portion comprises aqueous condensate, and further comprising recovering said aqueous condensate from the mobilized portion to provide a portion of the steam generating medium, and
 when the aqueous condensate added to the steam generating medium comprises solids, evaporating a portion thereby generating steam, and concentrating solids in the accumulated portion of the steam generating medium.   
     
     
         10 . A method according to  claim 9 , wherein the combustion products comprise particulates that may solidify in the first or second zone, and wherein aqueous condensate is added to flush particulates into the reservoir of accumulated steam generating medium. 
     
     
         11 . A method according to  claim 1  wherein at least a portion of the steam and carbon dioxide are retained in the hydrocarbon matrix through repressurizaton of adjacent reservoir zones, voidage replacement and leakage to adjacent strata. 
     
     
         12 . A method according to  claim 1  comprising recovering at least 50% of the carbon dioxide that is delivered to the hydrocarbon bearing matrix material. 
     
     
         13 . A method according to  claim 1  comprising performing steps of combusting the fuel and contacting the steam generating medium with the products of combustion at a pressure of greater than 100 kPa above ambient pressure. 
     
     
         14 . A method according to  claim 1  wherein carbon dioxide recovered along with the mobilized portion is recovered at a pressure of greater than 100 kPa above ambient pressure 
     
     
         15 . A method according to  claim 1 , wherein the fuel is selected from the group consisting of fossil fuels, hydrocarbon derived fuels, refuse derived fuels, synthetic fuel, and mixtures thereof, wherein
 the fossil fuels are natural gas, anthracite, coal, sub-bituminous coal, lignite, and peat;   the hydrocarbon derived fuels are atmospheric residuals, vacuum residuals, asphaltene, pitch, char, and coke;   the refuse derived fuels are wood waste; municipal solid waste and sewage waste; and   the synthetic fuel is syngas.   
     
     
         16 . A method according to  claim 1  wherein the oxidant comprises at least 50 volume percent oxygen and more preferably 95 volume percent oxygen. 
     
     
         17 . A method according to  claim 1  wherein the moderator comprises one of liquid water, steam, recycled produced water, carbon dioxide, and mixtures thereof. 
     
     
         18 . A method according to  claim 1  wherein the steam generating medium comprises recycled produced water, and the step of contacting of the steam generating medium with the products of combustion causes boiling of water to produce steam. 
     
     
         19 . A method according to  claim 1  wherein step a) further comprises separating particulates from the compound heat medium before performing step b). 
     
     
         20 . A method according to  claim 19  wherein separating particulates comprises passing the compound heat medium through at least one of a Venturi scrubber, a vane scrubber and a wet scrubber before step b). 
     
     
         21 . A method according to  claim 1  wherein the fuel comprises an ash and the method further comprises, after contacting a steam generating medium with said products of combustion, a step of recovering a portion of resulting suspended and dissolved solids from the steam generating medium. 
     
     
         22 . A method according to  claim 1  wherein the mobilized portion of hydrocarbons further comprises one or more of dissolved and suspended solids and water soluble hydrocarbons and wherein after recovering produced water comprising said dissolved or suspended solids and water soluble hydrocarbons, injecting said produced water at step a) as one or both of a moderator and a steam generating medium, thereby combusting the water soluble hydrocarbons and separating the suspended and dissolved solids from the steam generating medium. 
     
     
         23 . A method according to  claim 1 , comprising recovering a heavy hydrocarbon from the matrix material. 
     
     
         24 . A method according to  claim 23  wherein the hydrocarbon bearing matrix material comprises mined material. 
     
     
         25 . A method according to  claim 1  wherein the oxidant for combustion comprises oxygen, and comprising providing oxygen by a ceramic autothermal recovery (CAR) process comprising delivering a portion of the compound heat medium for desorption of oxygen. 
     
     
         26 . A method according to  claim 1  wherein the combustion temperature in the combustion zone is greater than the melting temperature of at least one dissolved or suspended solid impurity in the combustion mixture. 
     
     
         27 . A system for extracting a hydrocarbon from a hydrocarbon bearing matrix material comprising:
 a compound heat medium generator comprising:
 a first zone for oxy-combustion of a fuel in the presence of an oxidant and a moderator to create products of combustion at an elevated temperature and pressure comprising carbon dioxide, 
 the first zone for oxy-combustion having inputs for fuel, oxidant and moderator, and an output for directing products of combustion to a second zone, 
 the second zone comprising an evaporation zone for contacting a steam generating medium with said products of combustion at elevated temperature and pressure, to generate steam, thereby generating a pressurized compound heat medium comprising products of combustion, carbon dioxide and steam at elevated temperature, the second zone having inputs for the steam generating medium, and an output to a third zone; 
 the third zone comprising a separation zone for accumulating condensates comprising unevaporated steam generating medium from the evaporation zone and sump means for recovering solids settled by gravity from the condensates; 
 an outlet from the second zone of the compound heat medium generator for coupling the compound heat medium generator to an injection means for delivering the compound heat medium at pressure to the hydrocarbon bearing matrix material, thereby condensing steam and heating and mobilizing a portion of hydrocarbons; and 
 a separation system for coupling to recovery means for recovering under pressure a mobilized portion comprising hydrocarbons and carbon dioxide, and separating pressurized carbon dioxide from the mobilized portion. 
   
     
     
         28 . A system according to  claim 27  wherein the separation system is coupled to at least one of the first and second zones for delivery of one or both of recycled produced water and recovered carbon dioxide thereto. 
     
     
         29 . A system according to  claim 27  further comprising a particulate separator for removing particulates from the compound heat medium before delivering the compound heat medium at pressure to the hydrocarbon bearing matrix material. 
     
     
         30 . A system according to  claim 27  wherein the-particulate separator comprises at least one of a Venturi scrubber, a vane scrubber and a wet scrubber. 
     
     
         31 . A system according to  claim 27  wherein the system further comprises an air separation unit for generating said oxidant for the first zone. 
     
     
         32 . A system according to  claim 31  wherein air separation unit comprises a ceramic autothermal recovery (CAR) unit, the CAR unit having input means for receiving a portion of the compound heat medium for desorption of oxygen, to generate oxidant for combustion. 
     
     
         33 . A system according to  claim 27  wherein:
 the injection means comprises a first connection for coupling to an injection well head; and 
 the recovery means comprises a second connection for coupling to a production wellhead. 
 
     
     
         34 . A system for generating a compound heat medium comprising steam and carbon dioxide for extraction of a hydrocarbon from a hydrocarbon bearing matrix material, the system comprising:
 a combustion zone (first zone) for oxy-combustion of a fuel in the presence of an oxidant and a moderator to create products of combustion at an elevated temperature and pressure comprising carbon dioxide, the first zone having inputs for fuel, oxidant and moderator and an output for directing products of combustion to an evaporation zone (second zone);   the evaporation zone for contacting a steam generating medium with said products of combustion at elevated temperature and pressure, thereby evaporating a portion of the steam generation medium to produce a pressurized compound heat medium comprising products of combustion, carbon dioxide and steam at elevated temperature;   the evaporation zone being vertically located below the combustion zone, with first outlet means from the combustion zone at the bottom of the combustion zone for directing the products of combustion for contacting the steam generating medium in the evaporation zone;   the evaporation zone being coupled to a third zone below the evaporation zone, the third zone comprising a separation zone for accumulating condensates comprising unevaporated steam generating medium from the evaporation zone, and a sump for recovering solids settled by gravity from the condensates;   a second outlet means from the evaporation zone for delivery of compound heat medium to a particulate separator, for producing scrubbed compound heat medium,   and means for delivering at least one of condensates from the particulate separator, from the separation zone, and from the sump, to at least one of the combustion zone or evaporation zone, to provide at least a portion of the moderator or the steam generating medium; and   and a third outlet means from the particulate separator for delivery of scrubbed compound heat medium, at pressure, for injection into the hydrocarbon bearing matrix material.