STEAM ASSISTED GRAVITY DRAINAGE WITH ADDED OXYGEN ("SAGDOX") IN DEEP RESERVOIRS
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 .