Pilot block system to lock a blowout preventer stack

Abstract

A lock system includes a lock assembly for a movable component, a lock line configured to apply pressure to actuate the lock assembly, and a close line configured to apply pressure to close the movable component. The lock system also includes a pilot block with a respective pilot-operated check valve along the lock line, wherein the pilot block is actuated via a respective target pressure in the close line.

1 . A lock system, comprising:
 a lock assembly for a movable component;   a lock line configured to apply pressure to actuate the lock assembly;   a close line configured to apply pressure to close the movable component; and   a pilot block comprising a respective pilot-operated check valve along the lock line, wherein the pilot block is actuated via a respective target pressure in the close line.   
     
     
         2 . The lock system of  claim 1  wherein the lock assembly comprises a rotary lock assembly. 
     
     
         3 . The lock system of  claim 1 , wherein a lock member of the lock assembly is coaxial with the movable component. 
     
     
         4 . The lock system of  claim 1 , comprising:
 an unlock line configured to apply pressure to actuate the lock assembly; and   the pilot block comprising a respective pilot-operated check valve along the unlock line.   
     
     
         5 . The lock system of  claim 1 , comprising:
 an additional lock assembly for an additional movable component; and   a common line to fluidly couple the lock assembly and the additional lock assembly, such that respective lock members of the lock assembly and the additional lock assembly move in a coordinated manner.   
     
     
         6 . The lock system of  claim 1 , comprising:
 an additional lock assembly for an additional movable component;   the lock line configured to apply pressure to actuate the additional lock assembly;   an additional close line configured to apply pressure to close the additional movable component; and   an additional pilot block comprising a respective pilot-operated check valve along the lock line, wherein the additional pilot block is actuated via a respective target pressure in the additional close line.   
     
     
         7 . The lock system of  claim 1 , wherein the movable component comprises a ram of a blowout preventer. 
     
     
         8 . The lock system of  claim 1 , wherein the pressure to close the movable component corresponds to the respective target pressure to enable adjustment of a lock member of the lock assembly to a lock position while the movable component is in a closed position. 
     
     
         9 . The lock system of  claim 1 , comprising a controller, wherein the controller comprises:
 a close input selectable by an operator to initiate application of the close pressure through the close line; and   a lock input selectable by the operator to initiate application of the lock pressure through the lock line.   
     
     
         10 . The lock system of  claim 1 , comprising a pilot block housing, wherein the pilot block housing supports the respective pilot-operated check valve and a flow regulator. 
     
     
         11 . The lock system of  claim 10 , wherein the pilot block housing comprises or is coupled to a fire shield material that surrounds at least the flow regulator. 
     
     
         12 . A method of operating a lock system, the method comprising:
 providing a closing flow of hydraulic fluid through a close line to adjust a movable component to a closed position;   actuating a pilot block via sufficient pressure of the closing flow of hydraulic fluid in the close line; and   providing a locking flow of hydraulic fluid through a lock line and across the pilot block to adjust a lock member of a lock assembly to a lock position to maintain the movable component in the closed position.   
     
     
         13 . The method of  claim 12 , comprising:
 providing the closing flow of the hydraulic fluid through the close line in response to a close command input by an operator at a controller; and   providing the locking flow of hydraulic fluid through the lock line in response to a lock command input by the operator at the controller.   
     
     
         14 . The method of  claim 12 , comprising blocking the locking flow of hydraulic fluid across an additional pilot block in absence of sufficient pressure in an additional close line associated with the additional pilot block. 
     
     
         15 . The method of  claim 12 , wherein the movable component comprises a ram of a blowout preventer. 
     
     
         16 . The method of  claim 12 , comprising adjusting the locking flow of hydraulic fluid via a flow regulator of the pilot block. 
     
     
         17 . A system, comprising:
 a movable component;   a movable component actuator configured to drive the movable component between an open position and a closed position;   a lock member;   a lock actuator configured to drive the lock member between an unlock position and a lock position; and   a pilot block comprising at least one pilot-operated check valve across a lock line that fluidly couples a hydraulic fluid source to the lock actuator, wherein the at least one pilot-operated check valve is configured to be actuated via application of sufficient pressure in a close line that fluidly couples the hydraulic fluid source to the movable component actuator.   
     
     
         18 . The system of  claim 17 , wherein the movable component comprises a ram of a blowout preventer. 
     
     
         19 . The system of  claim 17 , comprising:
 an additional movable component;   an additional movable component actuator configured to drive the additional movable component between a respective open position and a respective closed position;   an additional lock member;   an additional lock actuator configured to drive the additional lock member between a respective unlock position and a respective lock position; and   an additional pilot block comprising at least one respective pilot-operated check valve across the lock line that fluidly couples the hydraulic fluid source to the additional lock actuator, wherein the at least one respective pilot-operated check valve is configured to be actuated via application of sufficient pressure in a respective close line that fluidly couples the hydraulic fluid source to the additional movable component actuator.   
     
     
         20 . The system of  claim 17 , comprising:
 a body that supports the movable component; and   a pilot block housing that supports the at least one pilot-operated check valve and a flow regulator, wherein the pilot block housing is coupled to the body.