Emergency control system for subsea blowout preventer

Abstract

An emergency control system (ECS) for a subsea blowout preventer (BOP) includes a frame having a mud mat for engaging a seafloor; an ECS accumulator connected to the frame; a BOP interface connected to the frame and operable to connect to a stack interface of a BOP stack; a valve connected to the frame and operable to supply hydraulic fluid from the ECS accumulator to the interface; an acoustic receiver; and a controller operable to receive an instruction signal from the acoustic receiver and open the valve.

1 . An emergency control system (ECS) for a subsea blowout preventer (BOP), comprising:
 a frame having a mud mat for engaging a seafloor;   an ECS accumulator connected to the frame;   a BOP interface connected to the frame and operable to connect to a stack interface of a BOP stack;   a valve connected to the frame and operable to supply hydraulic fluid from the ECS accumulator to the stack interface;   an acoustic receiver; and   a controller operable to receive an instruction signal from the acoustic receiver and open the valve.   
     
     
         2 . The ECS of  claim 1 , further comprising a vessel interface in communication with the controller and operable to receive an umbilical from a support vessel. 
     
     
         3 . The ECS of  claim 2 , further comprising a choke/kill line connected to the BOP and vessel interfaces. 
     
     
         4 . The ECS of  claim 3 , further comprising a choke valve disposed in the choke/kill line. 
     
     
         5 . The ECS of  claim 2 , further comprising an injection line connected to the BOP and vessel interfaces and having a check valve disposed therein. 
     
     
         6 . The ECS of  claim 1 , further comprising a battery in communication with the controller. 
     
     
         7 . A blowout preventer (BOP) system, comprising:
 the ECS of  claim 1 ;   a BOP stack, comprising:
 a shear and/or blind ram preventer; 
 a BOP accumulator; 
 a wellhead connector; 
 a lower marine riser package having a control pod for selectively providing fluid communication between the BOP accumulator and the ram preventer; 
 the stack interface; 
 a hydraulic line extending from the stack interface to an actuator of the ram preventer. 
   
     
     
         8 . The BOP system of  claim 7 , wherein the hydraulic line has a length greater than or equal to two hundred and fifty feet. 
     
     
         9 . The ECS of  claim 1 , wherein the frame is a skid frame and further has retractable legs for engaging the seafloor. 
     
     
         10 . A method of safeguarding a subsea drilling operation, comprising:
 lowering an emergency control system (ECS) to a seafloor, the ECS comprising:   
       an ECS accumulator, a BOP interface, a hydraulic line extending from the ECS accumulator to the BOP interface, and a valve disposed in the hydraulic line; and
 operating a remotely operated vehicle (ROV) to connect the BOP interface to a stack interface of a subsea blowout preventer (BOP) stack, wherein the ECS is located at a substantial distance from the BOP stack. 
 
     
     
         11 . The method of  claim 10 , wherein:
 the ECS further comprises an acoustic receiver and a controller, and   the method further comprises sending an acoustic instruction signal to the ECS in response to a blowout, wherein the controller opens the valve in response to receiving the instruction signal, thereby providing hydraulic fluid to the stack interface.   
     
     
         12 . The method of  claim 11 , wherein:
 the ECS further comprises a vessel interface, and   the method further comprises connecting an umbilical from a support vessel to the ECS interface.   
     
     
         13 . The method of  claim 12 , wherein:
 the ECS further comprises a choke/kill line connected to the BOP and vessel interfaces, and   the method further comprises pumping kill fluid from the vessel to the stack interface via the ECS.   
     
     
         14 . The method of  claim 13 , wherein:
 the ECS further comprises a choke valve disposed in the choke/kill line, and   the method further comprises flowing production fluid from the stack interface to the vessel via the ECS.   
     
     
         15 . The method of  claim 12 , wherein:
 the ECS further comprises an injection line connected to the BOP and vessel interfaces, and   the method further comprises pumping dispersant or hydrates inhibitor from the vessel to the stack interface via the ECS.