Method for initiating circulation for steam assisted gravity drainage
A method for initiating steam assisted gravity drainage (SAGD) mobilization and recovery of hydrocarbons in a hydrocarbon-bearing formation includes initially forming a circulation path by connecting SAGD injection well and a circulation well. The circulation well can be a SAGD production well or a separate well completed adjacent a toe of the injection well. Initially, a thermal carrier such as steam or flue gases, is circulated, forming a thermal chamber about the injection well. One initial start-up is complete, the circulation path is decoupled for further propagating the thermal chamber and establishing steady-state SAGD operations.
1. A method for initiating steam assisted gravity drainage (SAGD) mobilization and recovery of hydrocarbons in a hydrocarbon-bearing formation comprising:
completing a SAGD well-pair into the formation, the well-pair having an injection well arranged generally parallel to, and spaced above, a production well, the injection well having a toe;
establishing a uni-directional thermal stimulation circulation path along the injection well by drilling an inter-well connection between the injection well and the production well;
circulating a thermal carrier having thermal energy between the injection well and the inter-well connection;
forming an initial thermal chamber along at least a portion of the injection well; and
mobilizing the hydrocarbons for recovery from the production well.
2. The method of claim 1 wherein connecting the injection well to the inter-well connection comprises connecting the toe of the injection well to the production well.
3. The method of claim 2 wherein the circulation of the thermal carrier comprises introduction of the thermal carrier through the injection well.
4. The method of claim 1 wherein the circulating of the thermal carrier comprises introducing steam into the injection well.
5. The method of claim 1 further comprising generating steam in the injection well.
6. The method of claim 1 , wherein drilling between the injection well and the production well further comprises when completing the SAGD well-pair, sloping the toe of the injection well downwards to intercept the production well or sloping a toe of the production well upwards to intercept the injection well.
7. The method of claim 1 further comprising
completing a thermal well at or adjacent the toe of the injection well for forming the inter-well connection.
8. The method of claim 7 , further comprising:
completing more than two or more SAGD well-pairs; and
wherein completing a thermal well at or adjacent the toe of the injection well further comprises:
completing a thermal well generally about the toes of the injection wells of several of the more than two or more SAGD well-pairs for communication of the thermal carrier therebetween.
9. The method of claim 8 , wherein circulating the thermal carrier further comprises:
operating a downhole burner for generating steam and hot, non-condensable gases;
circulating the steam and hot, non-condensable gases along the injection well, and
venting non-condensable gases through the inter-well connection.
10. The method of claim 9 further comprising locating the downhole burner in the injection well.
11. The method of claim 9 further comprising locating the downhole burner in the thermal well.
12. The method of claim 2 wherein after establishing and forming an initial thermal chamber along at least a portion of the injection well, the method further comprising:
blocking the circulation path between injection well and the production; and
establishing steady-state operations between the injection well and the production well.
13. The method of claim 1 , wherein circulating the carrier further comprises:
operating a downhole burner for generating steam and hot, non-condensable gases;
circulating the steam and hot, non-condensable gases along the injection well, and
venting non-condensable gases from the production well.
14. The method of claim 13 , further comprising locating the downhole burner in the injection well.