Enhanced crude oil recovery method and system

Abstract

An enhanced crude oil recovery method comprises: injecting steam into a steam injection conduit ( 5 ) which is retrievably arranged in a steam injection well ( 1 ); inducing the steam to flow from the interior of steam injection conduit ( 5 ) through gradually widening steam injection channels ( 6 ) traversing the wall of the conduit ( 5 ) into the surrounding formation ( 2 ); and producing crude oil heated by the injected steam from the formation ( 2 ).

1 . An enhanced crude oil recovery method, comprising:
 injecting steam into a steam injection conduit which is retrievably arranged in a steam injection well;   inducing the steam to flow from the interior of steam injection conduit through gradually widening steam injection channels traversing the wall of the conduit into the surrounding formation; and   producing crude oil heated by the injected steam from the formation.   
   
   
       2 . The method of  claim 1 , wherein each gradually widening steam injection channel comprises:
 a tubular inflow section in which a tubular steam injection nozzle is arranged; and   an expansion section, which provides a steam expansion chamber for conveying steam from the nozzle into a space between the outer surface of the steam injection conduit and the inner surface of a at least partially permeable well liner which is arranged within the steam injection well.   
   
   
       3 . The method of  claim 1 , wherein
 each gradually widening steam injection channel is arranged in a side pocket in a thick walled section of the steam injection conduit, which has a smaller internal width than adjacent sections of the steam injection conduit;   the tubular inflow section of each steam injection channel is drilled from an end face of the thick walled section through the wall of the thick walled section in a direction substantially parallel to the longitudinal axis of the steam injection conduit; and   the expansion section of each steam injection channel is machined from the outer surface of the thick walled section such that it intersects the tubular inflow section.   
   
   
       4 . The method of  claim 3 , wherein the expansion section has a central axis which intersects or crosses the longitudinal axis of the steam injection conduit at an acute angle between 6 and 60 degrees relative to the longitudinal axis. 
   
   
       5 . The method of  claim 4 , wherein the steam injection conduit is substantially coaxial to a surrounding at least partially permeable well liner such that a substantially annular space is present between the conduit and liner, in which space an annular seal is arranged at a location between a wellhead of the steam injection well and the gradually widening steam injection channels. 
   
   
       6 . The method of  claim 5 , wherein the method further comprises converting the produced crude oil into a transportation fuel and/or other chemical end products. 
   
   
       7 . An enhanced crude oil recovery system comprising gradually widening steam injection channels traversing the wall of a steam injection conduit, which is configured to be retrievably arranged within a steam injection well and to inject steam into a formation surrounding the well. 
   
   
       8 . The system of  claim 7 , wherein each gradually widening steam injection channel comprises:
 a tubular inflow section in which a tubular steam injection nozzle is arranged; and   a expansion section, which intersects the tubular inflow section and provides a steam expansion chamber for conveying steam from the nozzle into a space between the outer surface of the steam injection conduit and the inner surface of a at least partially permeable well liner which is arranged within the steam injection well.   
   
   
       9 . The steam injection system of  claim 8 , wherein
 each gradually widening steam injection channel is arranged in a side pocket in a thick walled section of the steam injection conduit, which has a smaller internal width than adjacent sections of the steam injection conduit;   the tubular inflow section of each steam injection channel is drilled from an end face of the thick walled section through the wall of the thick walled section in a direction substantially parallel to the longitudinal axis of the steam injection conduit; and   the expansion section of each steam injection channel is machined from the outer surface of the thick walled section such that it intersects the tubular inflow section.   
   
   
       10 . The steam injection system of  claim 9 , wherein the expansion section has a central axis which intersects or crosses the longitudinal axis of the steam injection conduit at an acute angle between 6 and 60 degrees relative to the longitudinal axis.