In situ combustion with a mobile fluid zone

Abstract

A process for hydrocarbon recovery from an oil sands reservoir having a mobile fluid zone above a bitumen zone. The process includes generating, in the bitumen zone a mobilized and through a mobility enhancing process. The process also includes recovering at least some of the original oil-in-place and injecting an oxidizing gas through an oxidizing gas injection well into the reservoir to support in situ combustion in the reservoir. The process includes generating fluid communication between the mobile fluid zone and the mobilized zone and recovering hydrocarbons mobilized by the in situ combustion using a hydrocarbon production well that is in fluid communication with the mobile fluid zone and the mobilized zone.

What is claimed is: 
     
         1 . A process for hydrocarbon recovery from an oil sands reservoir having a mobile fluid zone above a bitumen zone, the process comprising:
 generating, in the bitumen zone and through a mobility enhancing process, a mobilized zone by recovering at least some of the original oil-in-place;   injecting an oxidizing gas through an oxidizing gas injection well into the reservoir to support in situ combustion in the reservoir;   generating fluid communication between the mobile fluid zone and the mobilized zone; and   recovering hydrocarbons mobilized by the in situ combustion using a hydrocarbon production well that is in fluid communication with the mobile fluid zone and the mobilized zone, the in situ combustion propagating at least in the mobilized zone.   
     
     
         2 . The process according to  claim 1 , wherein the mobility enhancing process is a steam-assisted hydrocarbon recovery process. 
     
     
         3 . The process according to  claim 2 , wherein the steam-assisted hydrocarbon recovery process is steam-assisted gravity drainage. 
     
     
         4 . The process according to  claim 1 , wherein the mobility enhancing process generates the fluid communication between the mobile fluid zone and the mobilized zone. 
     
     
         5 . The process according to  claim 1 , wherein the mobilized zone and the mobile fluid zone are not in fluid communication before the in situ combustion process is initiated, and wherein the in situ combustion generates the fluid communication between the mobile fluid zone and the mobilized zone. 
     
     
         6 . The process according to  claim 1 , further comprising producing combustion gases through a combustion gas production well. 
     
     
         7 . The process according to  claim 6 , wherein the hydrocarbon production well and the combustion gas production well are a generally horizontal well pair. 
     
     
         8 . The process according to  claim 7 , wherein the generally horizontal well pair is used to generate the mobilized zone through the mobility enhancing process. 
     
     
         9 . The process according to  claim 1 , wherein the hydrocarbon production well and the oxidizing gas injection well are a generally horizontal well pair. 
     
     
         10 . The process according to  claim 9 , wherein the generally horizontal well pair is used to generate the mobilized zone through the mobility enhancing process. 
     
     
         11 . The process according to  claim 10 , further comprising producing combustion gases through a combustion gas production well. 
     
     
         12 . The process according to  claim 11 , wherein the combustion gas production well is a former mobility enhancing process well that is in gaseous communication with the oxidizing gas injection well. 
     
     
         13 . The process according to  claim 1 , wherein the oxidizing gas is injected continuously. 
     
     
         14 . The process according to  claim 1 , wherein the oxidizing gas is injected intermittently. 
     
     
         15 . The process according to  claim 1 , wherein water is injected in addition to the oxidizing gas. 
     
     
         16 . The process according to  claim 1  wherein the mobile fluid zone is a gas zone. 
     
     
         17 . The process according to  claim 16 , wherein the oxidizing gas is injected into the gas zone. 
     
     
         18 . The process according to  claim 16 , wherein the oxidizing gas is injected into the mobilized zone. 
     
     
         19 . The process according to  claim 16 , wherein the in situ combustion propagates through the mobilized zone and through the mobile fluid zone. 
     
     
         20 . The process according to  claim 1  wherein the mobile fluid zone is a water zone. 
     
     
         21 . The process according to  claim 20 , wherein the oxidizing gas is injected into the mobilized zone. 
     
     
         22 . The process according to  claim 20 , wherein the in situ combustion generates steam from water in the water zone and the generated steam aids in the mobilization of hydrocarbons in the reservoir. 
     
     
         23 . A process for hydrocarbon recovery from an oil sands reservoir having a gas zone above a bitumen zone, the process comprising:
 utilizing a generally horizontal well pair to generate, through steam-assisted gravity drainage, a steam chamber in the bitumen zone that is in gaseous communication with the gas zone, wherein the generally horizontal well pair comprises: a generally horizontal segment of a hydrocarbon production well, and a generally horizontal segment of a steam injection well;   injecting an oxidizing gas into the gas zone through an oxidizing gas injection well including an oxidizing gas injection segment, the oxidizing gas supporting in situ combustion in the reservoir and the in situ combustion propagating at least in the steam chamber;   recovering hydrocarbons mobilized by the in situ combustion using the hydrocarbon production well; and   producing combustion gas through the steam injection well;   the generally horizontal segment of the steam injection well being disposed generally parallel to and spaced vertically above the horizontal segment of the hydrocarbon production well, and the injection segment of the oxidizing gas injection well being spaced generally above the segment of the hydrocarbon production well and generally above the segment of the steam injection well.   
     
     
         24 . A process for hydrocarbon recovery from an oil sands reservoir having a water zone above a bitumen zone, the process comprising:
 generating, in the bitumen zone and through steam-assisted gravity drainage, a steam chamber in the bitumen zone that is in fluid communication with the water zone;   injecting an oxidizing gas through an oxidizing gas injection well into the steam chamber to support in situ combustion in the reservoir and the in situ combustion propagating at least in the steam chamber;   generating steam by heating water in the water zone through the in situ combustion, the generated steam aiding in mobilizing hydrocarbons in the reservoir;   and recovering hydrocarbons mobilized by the in situ combustion using a hydrocarbon production well that is in fluid communication with the water zone and the steam chamber.