Steam assisted gravity drainage with added oxygen ("sagdox") in deep reservoirs

Abstract

A process to recover hydrocarbons, from a hydrocarbon reservoir having a bottom, using a substantially horizontal production well, the substantially horizontal production well having a toe and a heel, the process including: (a) injecting oxygen into the hydrocarbon reservoir, the horizontal production well having at least one perforation zone for contact with the reservoir; (b) injecting steam into the hydrocarbon reservoir; the oxygen producing in situ heat and in situ carbon dioxide by combustion and the steam producing in situ heat by conduction and condensation; the in situ carbon dioxide dissolving into the liquid hydrocarbon, lowering its viscosity; (c) recovering the reservoir liquid hydrocarbons of lowered viscosity using the substantially horizontal production well; and (d) optionally conveying the recovered liquid hydrocarbons to the surface; where the process is absent a removal step of any non-condensable gas from the reservoir.

1 . A process to recover hydrocarbons, from a hydrocarbon reservoir having a bottom, using a substantially horizontal production well, said substantially horizontal production well having a toe and a heel, said process comprising:
 (a) injecting oxygen into said hydrocarbon reservoir, said horizontal production well having at least one perforation zone for contact with said reservoir;   (b) injecting steam into said hydrocarbon reservoir; said oxygen producing in situ heat and in situ carbon dioxide by combustion and said steam producing in situ heat by conduction and condensation; said in situ carbon dioxide dissolving into the liquid hydrocarbon, lowering its viscosity;   (c) recovering said reservoir liquid hydrocarbons of lowered viscosity using said substantially horizontal production well; and   (d) optionally conveying said recovered liquid hydrocarbons to the surface; wherein said process is absent a removal step of any non-condensable gas from said reservoir.   
     
     
         2 . The process of  claim 2  wherein said hydrocarbon reservoir comprises at least one characteristic selected from the group consisting of:
 (a) an average depth greater than about 500 metres; 
 (b) an average pressure greater than about 800 psia, and combinations thereof. 
 
     
     
         3 . A process to recover liquid hydrocarbons, from a hydrocarbon reservoir having a bottom, using a horizontal production well, comprising:
 (a) Completing the horizontal production well within 2 metres of the reservoir bottom;   (b) injecting oxygen gas into the hydrocarbon reservoir within 50 metres from the horizontal production well and with a perforation (reservoir contact) zone less than 50 metres in length;   (c) injecting steam within 20 metres from the horizontal production well;   (d) the oxygen gas producing in situ heat and in situ carbon dioxide by combustion and the steam producing in situ heat by conduction and by condensation;   (e) said carbon dioxide dissolving into the reservoir hydrocarbon, lowering its viscosity;   (f) in situ heat causing the liquid hydrocarbon to be heated, also lowering its viscosity;   (g) the lower-viscosity reservoir liquid hydrocarbon draining by gravity to the horizontal production well where it is conveyed (or pumped) to the surface; and   (h) the process pressure (in the reservoir) is greater than 800 psia.   
     
     
         4 . A process according to  claim 1  or  3 , wherein oxygen to steam injected is controlled so that produced water to oil (v/v liquid) has a ratio greater than 0.5. 
     
     
         5 . A process according to  claim 4 , wherein the ratio of produced water to oil (v/v liquid) is between 0.5 and 2.0. 
     
     
         6 . A process according to  claim 3 , wherein said hydrocarbon reservoir is positioned at least 500 metres below a ground surface. 
     
     
         7 . A process according to  claim 3 , wherein steam is injected within 10 metres from the horizontal production well. 
     
     
         8 . A process according to  claim 1  or  7 , wherein steam is injected using a substantially parallel horizontal well to the horizontal production well and located about 3 metres to 8 metres above the horizontal production well. 
     
     
         9 . A process according to  claim 1  or  7 , wherein steam is injected into the reservoir using at least one well selected from the group consisting of a single substantially vertical well or a plurality of substantially vertical wells. 
     
     
         10 . A process according to  claim 1 , wherein the oxygen is injected into the reservoir using at least one well selected from the group consisting of a single substantially vertical well or a plurality of substantially vertical wells. 
     
     
         11 . A process according to  claim 9 , wherein steam and oxygen are comingled on the surface and injected into the reservoir. 
     
     
         12 . A process according to  claim 10 , wherein steam and oxygen are segregated and injected separately into the reservoir. 
     
     
         13 . A process according to  claim 12  wherein said steam and oxygen are segregated using concentric tubing and packers with steam in a central tubing of said concentric tubing surrounded by oxygen in an adjacent annulus and said oxygen is injected at a higher elevation of said steam injected into the reservoir. 
     
     
         14 . A process according to  claim 13 , wherein said steam and oxygen are injected into said reservoir using a single substantially vertical well, wherein said single substantially vertical well is completed within 50 metres from the toe of the horizontal production well. 
     
     
         15 . A process according to  claim 1  or  3  wherein said reservoir has a pressure such that substantially no free CO 2  is produced in the production well. 
     
     
         16 . A process according to  claim 1  or  3  wherein said process has an operating in situ pressure and an oxygen/steam (v/v) ratio such that the substantially horizontal production well is substantially free of free CO 2 .