Well configurations for limited reflux

Abstract

Methods and systems produce petroleum products by steam assisted gravity drainage with dual producers separated vertically and laterally from at least one injector. Placement of the producers limits temperature rise of draining fluids and hence reflux of non-condensable gases injected with steam. In particular, the fluids drain along a steam chamber boundary for recovery at positions that are not in a direct downward path from where the injector is introducing heat.

1 . A method of recovering hydrocarbons, comprising:
 introducing a gaseous mixture including steam and non-condensable gas (NCG) into an injection well having a horizontal length through which the mixture passes into a formation; and   recovering a petroleum fluid from first and second production wells spaced laterally from one another by 10 to 20 meters and oriented horizontal and parallel to the horizontal length of the injection well that is disposed in vertical alignment 1 to 10 meters above a midpoint between the production wells.   
     
     
         2 . The method according to  claim 1 , further comprising generating a steam chamber within the formation and drainage pathways at a boundary of the chamber that end at the production wells and remain below a threshold temperature for retaining the NCG in solution. 
     
     
         3 . The method according to  claim 1 , wherein the NCG includes at least one of nitrogen, air, carbon dioxide, flue gas, hydrogen sulfide, hydrogen, anhydrous ammonia. 
     
     
         4 . The method according to  claim 1 , further comprising creating the mixture with a direct steam generator. 
     
     
         5 . The method according to  claim 1 , wherein the NCG includes a hydrocarbon solvent. 
     
     
         6 . The method according to  claim 1 , wherein the NCG includes a hydrocarbon solvent with between one and four carbon atoms per molecule. 
     
     
         7 . The method according to  claim 1 , further comprising introducing the mixture into an auxiliary well disposed in vertical alignment and above the injection well. 
     
     
         8 . The method according to  claim 1 , further comprising injecting the mixture into an auxiliary well above the horizontal length of the injection well after stopping introduction of the mixture into the injection well. 
     
     
         9 . The method according to  claim 1 , wherein the first and second production wells are multilaterals from a common wellbore. 
     
     
         10 . The method according to  claim 1 , wherein the production wells are used upon initial development of a steam chamber above the injection well. 
     
     
         11 . A method of recovering hydrocarbons, comprising:
 introducing a gaseous mixture including steam and non-condensable gas (NCG) into an injection well having a horizontal length through which the mixture passes into a formation;   generating a steam chamber within the formation and drainage pathways at a boundary of the chamber that end at first and second production wells and remain below a threshold temperature for retaining the NCG in solution due to location of the production wells below and on each side of the injection well; and   recovering a petroleum fluid from the production wells that spaced apart by 10 to 20 meters and are oriented horizontal and parallel to the horizontal length of the injection well.   
     
     
         12 . The method according to  claim 11 , further comprising introducing the mixture into an auxiliary well disposed in vertical alignment and above the injection well. 
     
     
         13 . The method according to  claim 11 , wherein the steam chamber is generated without recovery in an area of the formation having vertical alignment with the injection well. 
     
     
         14 . The method according to  claim 11 , wherein the NCG includes carbon dioxide. 
     
     
         15 . A system for recovering hydrocarbons, comprising:
 an injection well disposed in a formation and in fluid communication with a gaseous mixture of steam and non-condensable gas (NCG), wherein the injection well has a horizontal length through which the mixture is passable into the formation; and   first and second production wells spaced laterally from one another by 10 to 20 meters and oriented horizontal and parallel to the horizontal length of the injection well that is disposed in vertical alignment 1 to 10 meters above a midpoint between the production wells through which a petroleum fluid is recoverable.   
     
     
         16 . The system according to  claim 15 , wherein the gaseous mixture is a direct steam generator product. 
     
     
         17 . The system according to  claim 15 , further comprising an auxiliary well disposed in vertical alignment above the injection well and through which the mixture is passable into the formation.