Non-carcassed, collapse resistant, control line for use subsea and method of use

Abstract

A flexible conduit is adapted for use subsea by providing the flexible conduit, comprising a non-carcassed, collapse resistant control line further comprising a reinforcing carcass, with a first valve disposed at a first end of the control line and a second valve disposed at a second end of the control line. The second end is disposed at a predetermined depth subsea. Once deployed, the first valve and the second valve are selectively engaged and/or disengaged to maintain a predetermined pressure of fluid inside the flexible conduit. In certain embodiments, the second valve, at a detected fluid pressure, is moved to a predetermined position which allows fluid inside the flexible conduit to be vented subsea, downstream of the second valve, through a vent port.

1 . A flexible conduit for use subsea, comprising: 
 a. a non-carcassed, collapse resistant control line further comprising a reinforcing carcass;    b. a first valve, comprising an open position and a close position, disposed at a first end of the control line; and    c. a second valve, comprising an open position and a close position, disposed at a second end of the control line, the second end adapted to be disposed at a predetermined subsea depth.    
   
   
       2 . The flexible conduit of  claim 1  wherein the reinforcing carcass comprises a metal carcass.  
   
   
       3 . The flexible conduit of  claim 1  wherein the flexible conduit is a single conduit.  
   
   
       4 . The flexible conduit of  claim 1  wherein the first valve is a check valve.  
   
   
       5 . The flexible conduit of  claim 1  wherein the first valve comprises a spring whose force must be overcome to introduce pressure into flexible conduit.  
   
   
       6 . The flexible conduit of  claim 1  wherein the second valve is a relief valve, further comprising a vent port.  
   
   
       7 . The flexible conduit of  claim 7  wherein the second valve comprises a spring whose force must be overcome to introduce pressure into flexible conduit, the second valve comprising: 
 a. an open position at which pressure overcomes the second valve's restraint to allow fluid delivery to the desired location; and    b. a closed position, operative upon fluid pressure in the flexible conduit falling to a predetermined value, wherein supply pressure is blocked.    
   
   
       8 . The flexible conduit of  claim 1 , wherein the first valve and the second valve are adapted to connect to a Christmas tree.  
   
   
       9 . The flexible conduit of  claim 1  wherein the predetermined subsea depth defines a maximum water depth of around 8000 feet.  
   
   
       10 . A method of providing fluid through a flexible conduit subsea, comprising: 
 a. providing a flexible conduit for use subsea, the flexible conduit comprising a non-carcassed, collapse resistant control line further comprising a reinforcing carcass, a first valve disposed at a first end of the control line, and a second valve disposed at a second end of the control line;    b. disposing the second end at a predetermined depth subsea; and    c. selectively engaging or disengaging the first valve and the second valve to maintain a predetermined pressure of fluid inside the flexible conduit.    
   
   
       11 . The method of  claim 10 , further comprising placing the first valve and the second valve into a closed position when fluid pressure inside the flexible conduit drops to a predetermined level.  
   
   
       12 . The method of  claim 10 , wherein the predetermined pressure is sufficient to maintain a minimum fluid pressure within the flexible conduit.  
   
   
       13 . The method of  claim 12 , wherein the minimum fluid pressure is sufficient to prevent a collapse of predetermined portion of the flexible conduit which might otherwise occur in the presence of an ambient pressure to which the flexible conduit is exposed.  
   
   
       14 . The method of  claim 10 , further comprising: 
 a. providing the second valve with a vent port;    b. detecting a fluid pressure within the flexible conduit; and    c. enabling the second valve, at the detected fluid pressure, to move to a predetermined position which allows fluid inside the flexible conduit to be vented subsea, downstream of the second valve, through the vent port.    
   
   
       15 . The method of  claim 14 , wherein the second valve is enabled either automatically or under a control directive from a controller operatively in communication with the second valve.  
   
   
       16 . The method of  claim 14 , further comprising: 
 a. connecting at least one of the first valve or the second valve to a Christmas tree;    b. maintaining the fluid at a predetermined range having at least a minimum fluid pressure within the flexible conduit to prevent a collapse of the flexible condition at a depth while maintaining the ability to vent pressure downstream of a subsea valve.    
   
   
       17 . The method of  claim 16 , wherein the subsea valve is the second valve.  
   
   
       18 . The method of  claim 16 , further comprising: 
 a. upon detecting a predetermined pressure, shifting to a fail closed position of at least one of (i) a Christmas tree or (ii) tree control module valves; and    b. closing the flexible conduit by venting the supply pressure.