Patent ID: 8387691

Claim:
A method of producing hydrocarbons from a subterranean reservoir comprising: a. providing a SAGD well pair, including an injection well and a production well within the reservoir containing the hydrocarbons and a low pressure zone or loss zone at least partially overlaying the hydrocarbons, the low pressure zone or loss zone having a pressure of less than 1000 kPa; b. providing a lateral drainage (LD) well, laterally offset from the SAGD well pair within the reservoir; c. initiating operation of the SAGD well pair and the LD well to create or promote a common steam chamber within the reservoir between the hydrocarbons and the low pressure zone or loss zone and establish fluid communication among the injection well, production well, and the LD well; d. injecting steam into the steam chamber via at least one of the injection well and the LD well and withdrawing produced fluids from the steam chamber via at least one of the production well and the LD well to grow the steam chamber vertically between the hydrocarbons and the low pressure zone or loss zone until to minimize or prevent fluid loss into the low pressure or loss zone; and e. selectively co-injecting non-condensable gas (NCG) with the steam into the steam chamber at a selected rate and reducing the pressure of the steam chamber to control and optimize rise rate of the steam chamber by manipulating levels of the NCG in the steam chamber to promote an NCG buffer zone between the steam chamber and the low pressure zone or loss zone while encouraging lateral growth of the steam chamber while keeping saturation and condensation of the steam in the steam chamber at a level that provides control over breakthrough of the steam through the NCG buffer zone to the low pressure zone or loss zone; and f. operating the well pair and the LD well under conditions of a pressure in the steam chamber that is initially and briefly high to establish the steam chamber, but thereafter may be reduced to as low as 200 kPa to recover the hydrocarbons from the reservoir via the production well.