Steam distribution and conditioning assembly for enhanced oil recovery of viscous oil

Abstract

Methods and apparatus for enhanced and improved viscous oil recovery are disclosed. A horizontal well is drilled through the viscous oil formation. A specially designed tubing string includes outlets that deliver steam more uniformly into the entire horizontal extent of the well borehole. Heat from the steam mobilizes and lowers the viscosity of the heavy crude wherein the crude is then produced to the surface via conventional lift arrangements.

1 . A well assembly for injecting steam into a subterranean reservoir, the well assembly comprising:
 a string of tubing in fluid communication with a producing zone of a subterranean reservoir, the string of tubing comprising a substantially vertical section and a substantially horizontal section extending from a lower portion of the substantially vertical section, the substantially horizontal section defining at one end a heel portion and at an opposite end a toe portion;   an opening formed on the inner surface of the substantially horizontal section that defines an inlet;   an opening formed on the outer surface of the substantially horizontal section that defines an outlet;   a passageway extending between the inlet and the outlet such that steam received by the inlet is delivered to the outlet; and   a flow conditioning device being positioned in the string of tubing axially closer to the heel portion than the inlet to generate a more homogenous mixture of the vapor and liquid components of the two-phase steam.   
     
     
         2 . The well assembly of  claim 1 , wherein the flow conditioning device comprises a stator. 
     
     
         3 . The well assembly of  claim 1 , wherein the flow conditioning device comprises a plurality of axially spaced stators thereby defining a conditioning region. 
     
     
         4 . The well assembly of  claim 1 , wherein the flow conditioning device comprises a plurality of vanes extending inwardly from the inner surface of the string of tubing and around the circumference thereof. 
     
     
         5 . The well assembly of  claim 1 , wherein the flow conditioning device is adapted to allow a logging tool to travel therethrough. 
     
     
         6 . The well assembly of  claim 1 , wherein the flow conditioning device is positioned in the string of tubing a predetermined length upstream of the inlet, the predetermined length being between about four to six times the diameter of the string of tubing. 
     
     
         7 . The well assembly of  claim 1 , wherein the flow conditioning device is carried within the string of tubing. 
     
     
         8 . The well assembly of  claim 1 , wherein the flow conditioning device is positioned between segments of tubing within the substantially horizontal section of the string of tubing. 
     
     
         9 . The well assembly of  claim 1 , wherein:
 the string of tubing further comprises a reduced cross-sectional flow area; and   the inlet is formed in the reduced cross-sectional flow area.   
     
     
         10 . The well assembly of  claim 1 , wherein the inlet is axially closer to the heel portion than the outlet so that when steam is received by the passageway an axial momentum of the steam is maintained. 
     
     
         11 . The well assembly of  claim 1 , further comprising:
 an annulus formed in the outer surface of the string of tubing that extends around the circumference thereof, the annulus being in fluid communication with the outlet; and   a nozzle positioned within the annulus to control the flow of steam received from the outlet.   
     
     
         12 . A well assembly for injecting steam into a subterranean reservoir, the well assembly comprising:
 a string of tubing in fluid communication with a producing zone of a subterranean reservoir, the string of tubing comprising a substantially vertical section and a substantially horizontal section extending from a lower portion of the substantially vertical section, the substantially horizontal section defining at one end a heel portion and at an opposite end a toe portion;   an opening formed on the inner surface of the substantially horizontal section that defines an inlet;   an opening formed on the outer surface of the substantially horizontal section that defines an outlet;   a passageway extending between the inlet and the outlet such that steam received by the inlet is delivered to the outlet; and   a flow conditioning device being positioned in the string of tubing axially closer to the heel portion than the inlet, the flow conditioner comprising a plurality of vanes extending inwardly from the inner surface of the string of tubing and around the circumference thereof so that when steam is received by the plurality of vanes a more homogenous mixture of vapor and liquid components of the steam is generated.   
     
     
         13 . The well assembly of  claim 12 , wherein the plurality of vanes extending inwardly from the inner surface of the string of tubing and around the circumference thereof are axially spaced in the string of tubing, thereby defining a conditioning region. 
     
     
         14 . The well assembly of  claim 12 , wherein the flow conditioning device is positioned in the string of tubing a predetermined length upstream of the inlet, the predetermined length being between about four to six times the diameter of the string of tubing. 
     
     
         15 . The well assembly of  claim 12 , wherein the flow conditioning device is carried within the string of tubing. 
     
     
         16 . The well assembly of  claim 12 , wherein the flow conditioning device is positioned between segments of tubing within the substantially horizontal section of the string of tubing. 
     
     
         17 . The well assembly of  claim 12 , wherein:
 the string of tubing further comprises a reduced cross-sectional flow area; and   the inlet is formed in the reduced cross-sectional flow area.   
     
     
         18 . The well assembly of  claim 12 , wherein the inlet is axially closer to the heel portion than the outlet so that when steam is received by the passageway an axial momentum of the steam is maintained. 
     
     
         19 . The well assembly of  claim 12 , wherein the plurality of vanes extending inwardly from the inner surface of the string of tubing provide sufficient clearance to allow a logging tool to travel therethrough.