USE OF STEAM-ASSISTED GRAVITY DRAINAGE WITH OXYGEN ("SAGDOX") IN THE RECOVERY OF BITUMEN IN LEAN ZONES ("LZ-SAGDOX")
A process to recover hydrocarbons from a reservoir having at least one lean zone, wherein said lean zone has an initial bitumen saturation level less than about 0.6, said process including: i) Initially injecting of oxygen into said reservoir; ii) Allowing for combustion of said oxygen to vaporize connate water in said at least one lean zone; and iii) Recovering said hydrocarbons from said reservoir.
1 . A process to recover hydrocarbons from a reservoir having at least one lean zone, wherein said lean zone has an initial bitumen saturation level less than about 0.6, said process comprising:
i) Initially injecting of oxygen into said reservoir;
ii) Allowing for combustion of said oxygen to vaporize connate water in said at least one lean zone; and
iii) Recovering said hydrocarbons from said reservoir.
2 . A process according to claim 1 further comprising initial steam injection with oxygen into the reservoir then terminating said steam injection.
3 . The process of claim 1 where combustion occurs at temperatures higher than 400° C.
4 . The process of claim 1 where the oxygen has an oxygen content of 95 to 99.9 (v/v) percent.
5 . The process of claim 1 where the oxygen is air.
6 . The process of claim 5 where the air is enriched air with an oxygen containing content of 21 to 95 (v/v) percent.
7 . The process of claim 1 where the hydrocarbons are bitumen API density (<10; in situ viscosity>100,000 cp.).
8 . The process of claim 1 where the hydrocarbons are heavy oil (10<API<20); in situ viscosity>1000 cp.).
9 . A steam assisted gravity drainage with oxygen system for recovery of hydrocarbons from a reservoir having at least one lean zone, wherein said lean zone has an initial bitumen saturation level less than about 0.6, said system comprising:
i) A first well, having a toe and a heel, said first well within said lean zone containing reservoir, for capturing said hydrocarbons;
ii) A second well within said lean zone containing reservoir, for injection of oxygen into said lean zone containing reservoir;
iii) Said second well being located proximate said toe of said first well; and
iv) At least one vent gas means for venting any gas produced in said reservoir.
10 . A steam assisted gravity drainage with oxygen system for recovery of hydrocarbons for a reservoir having at least one lean zone, wherein said lean zone has an initial bitumen saturation level less than about 0.6, said system comprising:
i) A well, having a toe and a heel, said well being located within said lean zone containing reservoir; wherein said well further comprises:
a. At least one oxygen injection site proximate said toe, for injecting oxygen into said reservoir;
b. A hydrocarbon recovery site for recovery of said hydrocarbons from said reservoir; and
c. At least one vent gas site for venting any gas produced in said reservoir.
11 . The system of claim 9 where the vent gas means is selected from a group consisting of a single substantially vertical well or a plurality of substantially vertical wells.
12 . The system of claims 9 and 10 where the vent gas means is a segregated annulus section in the heel section of the horizontal well.
13 . The system of claim 9 where the at least one oxygen injection site is selected from a group consisting of a single substantially vertical well or a plurality of substantially vertical wells.
14 . The system of claim 10 where the at least one oxygen injection site is a segregated toe section of the horizontal well.
15 . The system of claim 10 wherein said toe of said well is at a level in said reservoir different than said heel of said well.
16 . The system of claim 10 wherein said toe level is at a level higher in said reservoir than said heel of said well.
17 . The system of claims 9 and 10 wherein said at least one vent gas site is distant said toe of said well.
18 . A process according to claim 1 , 9 or 10 where the lean zone thickness is less than 25 metres.