Flow completion system

Abstract

A flow completion system for controlling the flow of fluid from a well bore comprises a tubing spool which is positioned over the well bore, a tubing hanger which is landed in the tubing spool, a first pressure-containing barrier which is secured to the tubing hanger and which comprises a portion that sealingly engages the tubing spool, and a second pressure-containing barrier which is secured to the tubing hanger and which comprises a portion that sealing engages the tubing spool. In addition, each of the first and second pressure-containing barriers is capable of isolating the well bore from the environment during the production mode of operation of the flow completion system.

1 . A flow completion system for controlling the flow of fluid from a well bore, the flow completion system comprising: 
 a tubing spool which is positioned over the well bore;    a tubing hanger which is landed in the tubing spool;    a first pressure-containing barrier which is secured to the tubing hanger and which comprises a portion that sealingly engages the tubing spool; and    a second pressure-containing barrier which is secured to the tubing hanger and which comprises a portion that sealing engages the tubing spool;    wherein each of the first and second pressure-containing barriers is capable of isolating the well bore from the environment during the production mode of operation of the flow completion system.    
   
   
       2 . The flow completion system of  claim 1 , wherein the second pressure-containing barrier comprises the uppermost pressure-containing barrier between the well bore and the environment during the production mode of operation of the flow completion system.  
   
   
       3 . The flow completion system of  claim 1 , wherein the tubing hanger comprises: 
 an axially extending production bore which communicates with the well bore during the production mode of operation of the flow completion system; and    a production passageway which is connected to the production bore.    
   
   
       4 . The flow completion system of  claim 3 , wherein at least one of the first and second pressure-containing barriers comprises a portion which sealingly engages the production bore above the production passageway during the production mode of operation of the flow completion system.  
   
   
       5 . The flow completion system of  claim 4 , wherein each of the first and second pressure-containing barriers comprises a portion which sealingly engages the production bore above the production passageway during the production mode of operation of the flow completion system.  
   
   
       6 . The flow completion system of  claim 1 , wherein the tubing spool comprises: 
 a central bore in which the tubing hanger is landed;    means for providing fluid communication between a tubing annulus which is located below the tubing hanger and a portion of the central bore which is located above the tubing hanger.    
   
   
       7 . The flow completion system of  claim 6 , wherein the fluid communication means comprises an annulus passageway which communicates with the tubing annulus and a workover passageway which communicates between the annulus passageway and the portion of the central bore located above the tubing hanger.  
   
   
       8 . The flow completion system of  claim 7 , further comprising third and fourth pressure-containing barriers which are disposed in the fluid communication means and which are each capable of isolating the tubing annulus from the environment during the production mode of operation of the flow completion system.  
   
   
       9 . The flow completion system of  claim 8 , wherein the third pressure-containing barrier comprises a closure member which is disposed in one of the annulus passageway and the workover passageway.  
   
   
       10 . The flow completion system of  claim 9 , wherein the fourth pressure-containing barrier comprises a closure member which is disposed in the other of the annulus passageway and the workover passageway.  
   
   
       11 . A flow completion system for controlling the flow of fluid from a well bore, the flow completion system comprising: 
 a tubing spool which is mounted over the well bore and which comprises a central bore that extends axially therethrough and a production outlet that communicates with the central bore; and    a tubing hanger which is landed in the central bore and which is configured to support at least first and second pressure-containing barriers;    wherein each of the first and second pressure-containing barriers is capable of isolating the well bore from the environment during the production mode of operation of the flow completion system.    
   
   
       12 . The flow completion system of  claim 11 , wherein the second pressure-containing barrier comprises the uppermost pressure-containing barrier between the well bore and the environment during the production mode of operation of the flow completion system.  
   
   
       13 . The flow completion system of  claim 11 , wherein the tubing hanger comprises: 
 an axially extending production bore which communicates with the well bore during the production mode of operation of the flow completion system; and    a production passageway which extends between the production bore and the production outlet.    
   
   
       14 . The flow completion system of  claim 13 , wherein at least one of the first and second pressure-containing barriers comprises a portion which sealingly engages the production bore above the production passageway during the production mode of operation of the flow completion system.  
   
   
       15 . The flow completion system of  claim 14 , wherein each of the first and second pressure-containing barriers comprises a portion which sealingly engages the production bore above the production passageway during the production mode of operation of the flow completion system.  
   
   
       16 . The flow completion system of  claim 11 , wherein the tubing spool comprises means for providing fluid communication between a tubing annulus which is located below the tubing hanger and a portion of the central bore which is located above the tubing hanger.  
   
   
       17 . The flow completion system of  claim 16 , wherein the fluid communication means comprises an annulus passageway which communicates with the tubing annulus and a workover passageway which communicates between the annulus passageway and the portion of the central bore located above the tubing hanger.  
   
   
       18 . The flow completion system of  claim 17 , further comprising third and fourth pressure-containing barriers which are disposed in the fluid communication means and which are each capable of isolating the tubing annulus from the environment during the production mode of operation of the flow completion system.  
   
   
       19 . The flow completion system of  claim 18 , wherein the third pressure-containing barrier comprises a closure member which is disposed in one of the annulus passageway and the workover passageway.  
   
   
       20 . The flow completion system of  claim 19 , wherein the fourth pressure-containing barrier comprises a closure member which is disposed in the other of the annulus passageway and the workover passageway.  
   
   
       21 . In combination with a christmas tree which is installed over a well bore, the improvement comprising a tubing hanger which includes: 
 a first pressure-containing barrier which comprises a portion that sealingly engages the christmas tree;    a second pressure-containing barrier which comprises a portion that sealingly engages the christmas tree;    wherein each of the first and second pressure-containing barriers is capable of isolating the well bore from the environment during the production mode of operation of the christmas tree.    
   
   
       22 . The flow completion system of  claim 21 , wherein the second pressure-containing barrier comprises the uppermost pressure-containing barrier between the well bore and the environment during the production mode of operation of the christmas tree.  
   
   
       23 . The flow completion system of  claim 21 , wherein the tubing hanger comprises: 
 an axially extending production bore which communicates with the well bore during the production mode of operation of the christmas tree; and    a production passageway which extends between the production bore and the production outlet.    
   
   
       24 . The flow completion system of  claim 23 , wherein at least one of the first and second pressure-containing barriers comprises a portion which sealingly engages the production bore above the production passageway during the production mode of operation of the christmas tree.  
   
   
       25 . The flow completion system of  claim 24 , wherein each of the first and second pressure-containing barriers comprises a portion which sealingly engages the production bore above the production passageway during the production mode of operation of the christmas tree.  
   
   
       26 . The flow completion system of  claim 11 , wherein the christmas tree comprises: 
 a central bore in which the tubing hanger is landed; and    means for providing fluid communication between a tubing annulus which is located below the tubing hanger and a portion of the central bore which is located above the tubing hanger.    
   
   
       27 . The flow completion system of  claim 26 , wherein the fluid communication means comprises an annulus passageway which communicates with the tubing annulus and a workover passageway which communicates between the annulus passageway and the portion of the central bore located above the tubing hanger.  
   
   
       28 . The flow completion system of  claim 27 , further comprising third and fourth pressure-containing barriers which are disposed in the fluid communication means and which are each capable of isolating the tubing annulus from the environment during the production mode of operation of the christmas tree.  
   
   
       29 . The flow completion system of  claim 28 , wherein the third pressure-containing barrier comprises a closure member which is disposed in one of the annulus passageway and the workover passageway.  
   
   
       30 . The flow completion system of  claim 29 , wherein the fourth pressure-containing barrier comprises a closure member which is disposed in the other of the annulus passageway and the workover passageway.  
   
   
       31 . A tubing hanger for sealing a well bore having a tubing spool mounted at an upper end thereof, the tubing hanger comprising: 
 a generally cylindrical body which comprises an annular outer surface;    a production bore which extends axially through the body;    a production passageway which extends between the production bore and the outer surface;    a first closure member which is positioned in the production bore above the production passageway;    a first annular seal which mounted on the outer surface above the production passageway;    a second closure member which is positioned in the production bore above the first closure member; and    a second annular seal which is mounted on the outer surface above the first annular seal;    wherein when the tubing hanger is landed in the tubing spool, the first closure member and the first annular seal form a first pressure-containing barrier between the well bore and the environment and the second closure member and the second annular seal form a second pressure-containing barrier between the well bore and the environment.    
   
   
       32 . The flow completion system of  claim 31 , wherein the second pressure-containing barrier comprises the uppermost pressure-containing barrier between the well bore and the environment.