SAGD CONTROL IN LEAKY RESERVOIRS

1 . The use of water recycle ratio for controlling at least one SAGD parameter in a leaky bitumen reservoir.

2 . A process to control a steam injection rate for an individual Steam Assisted Gravity Drainage (SAGD) well pair, in a leaky bitumen reservoir, wherein said process comprises replacing a pressure control for an SAGD steam injection rate with a volume control determined by a Water Recycle Ratio (WRR).

3 . The use of claim 1 wherein said at least one parameter is selected from volume rate, pressure, temperature, and combinations.

4 . The process of claim 2 , where the leaky bitumen reservoir is determined to be leaky by at least one of geological knowledge of an interspersed Water Lean Zone (WLZ), top water or bottom water.

5 . The process of claim 2 , where the leaky bitumen reservoir is determined leaky by a cold water injection test prior to SAGD initiation.

6 . The process of claim 2 , where the leaky bitumen reservoir is deemed leaky when after 200 days or more of SAGD operation using pressure control for steam injection, the SAGD has a WRR that varies from 1.0 by more than 10 percent.

7 . The process of claim 2 , where a sub-cool control is maintained for liquids production.

8 . The process of claim 2 , where volume rate control is instituted by injecting a pre-set target volume rate of steam into the SAGD injector well.

9 . A process for controlling a steam injection volume rate in a Steam Assisted Gravity Drainage (SAGD) process in an impaired reservoir, wherein the steam injection volume rate is controlled by

i. Continually measuring a Water Recycle Ratio (WRR) for an SAGD well pair;

ii. Establishing a target for WRR; and

iii. If the actual WRR is less than the target WRR, reducing the steam injection rate until the target is achieved;

iv. If the actual WRR is greater than the target WRR, increasing the steam injection rate until the target is achieved.

10 . The process of claim 9 where the target WRR is between 0.9 and 1.0.

11 . The process of claim 9 , where the target WRR is between 1.0 and 1.5.

12 . The process of claim 2 , wherein the leaky bitumen reservoir is leaky due to an interspersed water lean zone (WLZ) within a net pay zone in said reservoir.

13 . The process of claim 2 , where the leaky bitumen reservoir is leaky due to a top water zone.

14 . The process of claim 2 , where the leaky bitumen reservoir is leaky due to a bottom water zone

15 . The process of claim 2 , wherein the leaky bitumen reservoir is leaky due to multiple factors comprising WLZ, top water and bottom water.

16 . The process of claim 2 , wherein the bitumen is a hydrocarbon with <10 API density and >100,000 cp viscosity, at native reservoir conditions.

17 . The process of claim 8 , wherein the measured SAGD pressure in the reservoir does not exceed:

i) the reservoir parting pressure, for unconsolidated reservoirs;

ii) the reservoir fracturing pressure, for consolidated reservoirs.

18 . The process of claim 17 , where the measured SAGD pressure does not exceed about 80 percent of the parting pressure or the fracturing pressure.

19 . The process of claim 16 , where the bitumen reservoir is located in the Athabasca region of Alberta, Canada.

20 . The process of claim 2 , where the minimum operating pressure is equal to the native reservoir pressure.