Mechanical barrier fluid pressure regulation for subsea systems

Abstract

A technique facilitates controlling barrier fluid via a mechanical pressure regulation system which may be coupled with a rotating machine at a subsea location. The mechanical pressure regulation system enables controlled supply of the barrier fluid to the rotating machine and comprises a mechanical valve mechanism. The mechanical valve mechanism automatically maintains a pressure differential between the barrier fluid and a process fluid within a desired range. According to an embodiment, the mechanical valve mechanism is mechanically actuated via pressures applied to a pilot piston so as to provide barrier fluid to the rotating machine when the pressure differential reaches a lower limit and to dump barrier fluid when the pressure differential reaches an upper limit.

1 - 9 . (canceled) 
     
     
         10 . A system, comprising:
 a mechanical pressure regulation system automatically actuatable in response to pressure differentials between a barrier fluid and a process fluid during pumping of the process fluid, the mechanical pressure regulation system comprising a pressure balanced supply valve having:
 a valve housing; 
 a valve end sealably engageable with a valve seat to separate a high-pressure supply chamber and a discharge chamber cooperating with a discharge nozzle; 
 a pilot piston mechanically coupled with the valve end and slidably positioned within a pilot chamber within the valve housing to separate a process fluid side of the pilot chamber from a barrier fluid side of the pilot chamber; and 
 a spring acting on the pilot piston to bias the valve end to an open flow position and to bias the pilot piston toward the barrier fluid side of the pilot chamber, the discharge chamber being in fluid communication with the barrier fluid side of the pilot chamber via a barrier fluid flow passage. 
   
     
     
         11 . The system as recited in  claim 10 , further comprising a subsea pumping system having a pump for pumping the process fluid, the pumping system being in fluid communication with the mechanical pressure regulation system via the barrier fluid flow passage and via a process fluid flow passage routed between the pump and the process fluid side of the pilot chamber. 
     
     
         12 . The system as recited in  claim 11 , wherein the mechanical pressure regulation system further comprises a bleed valve coupled between the barrier fluid flow passage and the process fluid flow passage. 
     
     
         13 . The system as recited in  claim 10 , wherein the pilot piston is mechanically coupled with the valve end via a valve stem. 
     
     
         14 . The system as recited in  claim 13 , wherein the mechanical pressure regulation system further comprises a seal positioned about the valve stem to prevent fluid communication between the high-pressure supply chamber and the pilot chamber. 
     
     
         15 . The system as recited in  claim 10 , further comprising a barrier fluid supply in fluid communication with the high-pressure supply chamber. 
     
     
         16 . The system as recited in  claim 15 , wherein the barrier fluid supply comprises a subsea umbilical. 
     
     
         17 - 20 . (canceled)