Modular, retrievable valve packs for blowout preventer multiplexer controls

Abstract

Retrievable sub-pods for use in a blowout preventer (BOP) stack, including systems of sub-pods and methods for use, are disclosed. The sub-pod includes a valve assembly, wherein the valve assembly includes a solenoid, an electronics interface, and a directional control valve. The sub-pod further includes a modular valve pack and a controller, wherein the modular valve pack comprises a manifold, and wherein the manifold is operable to support the valve assembly within the manifold.

What is claimed is: 
     
         1 . A retrievable sub-pod for use in a blowout preventer (BOP) stack, the retrievable sub-pod comprising:
 a valve assembly, wherein the valve assembly comprises a solenoid, an electronics interface, and a directional control valve;   a modular valve pack, wherein the modular valve pack comprises a manifold, and wherein the manifold is operable to support the valve assembly within the manifold; and   a controller, wherein the controller is operable to control a state of the valve assembly for carrying out functions in the BOP stack, wherein the sub-pod can be docked subsea within the BOP stack, and wherein the sub-pod can be removed from the BOP stack subsea and replaced in the BOP stack subsea by an alternative sub-pod.   
     
     
         2 . The retrievable sub-pod of  claim 1 , wherein the valve assembly comprises a pilot stage. 
     
     
         3 . The retrievable sub-pod of  claim 1 , wherein the sub-pod comprises more than one modular valve pack, the modular valve packs being stacked and separable subsea. 
     
     
         4 . The retrievable sub-pod of  claim 1 , further comprising a connection interface for connecting the retrievable sub-pod with hydraulic fluid, electronic communications, and power provided from the BOP stack. 
     
     
         5 . The retrievable sub-pod of  claim 4 , the connection interface comprising an electronic communications connection selected from the group consisting of: a controller area network vehicle bus (CANbus) and a Modbus. 
     
     
         6 . The retrievable sub-pod of  claim 1 , further comprising an electro-hydraulic (EH) closed-loop controlled regulator. 
     
     
         7 . The retrievable sub-pod of  claim 1 , further comprising a hydraulic connection wedge and plumbing operable to dock the sub-pod to the BOP stack and to distribute hydraulic fluid to components in the BOP stack. 
     
     
         8 . The retrievable sub-pod of  claim 1 , wherein pressure surrounding the solenoid is controlled by a pressure control device selected from the group consisting of: a pressure compensated dielectric fluid and a pressure-controlled enclosure. 
     
     
         9 . A decentralized BOP stack system, the system comprising:
 a lower marine riser package (LMRP) portion;   a lower stack portion, wherein the LMRP portion is disposed above the lower stack portion;   at least two retrievable sub-pods, wherein each retrievable sub-pod independently comprises:
 a valve assembly; 
 a modular valve pack, wherein the modular valve pack comprises a manifold, and wherein the manifold is operable to support the valve assembly within the manifold; and 
 a controller, wherein the controller is operable to control a state of the valve assembly for carrying out functions in the BOP stack system, wherein each sub-pod can be docked subsea within the BOP stack system, and wherein each sub-pod can be removed from the BOP stack system subsea and replaced in the BOP stack system subsea by an alternative sub-pod. 
   
     
     
         10 . The decentralized BOP stack system of  claim 9 , wherein the at least two retrievable sub-pods are disposed within the LMRP portion of the BOP stack system. 
     
     
         11 . The decentralized BOP stack system of  claim 9 , wherein at least one sub-pod is disposed within the lower stack portion of the BOP stack system. 
     
     
         12 . The decentralized BOP stack system of  claim 9 , wherein the at least two retrievable sub-pods are stacked together. 
     
     
         13 . The decentralized BOP stack system of  claim 9 , wherein an introduction of the at least two retrievable sub-pods to the system reduces a required amount of plumbing to operate the decentralized BOP stack system relative to the system without the at least two retrievable sub-pods. 
     
     
         14 . The decentralized BOP stack system of  claim 9 , wherein the valve assembly comprises a solenoid, an electronics interface, and a directional control valve. 
     
     
         15 . A method for decentralizing a BOP control pod in a BOP stack, the method comprising the steps of:
 integrating at least one sub-pod into the BOP stack, the at least one sub-pod connected to BOP stack hydraulics, communications, and a power supply;   modularizing the functions of the BOP control pod by assigning functions of the BOP control pod to the sub-pod; and   reducing an amount of tubing disposed in the BOP stack.   
     
     
         16 . The method of  claim 15 , wherein the step of integrating at least one sub-pod into the BOP stack occurs subsea. 
     
     
         17 . The method of  claim 15 , further comprising the steps of:
 retrieving the at least one sub-pod subsea from the BOP stack; and   replacing the at least one sub-pod subsea with an alternative sub-pod.   
     
     
         18 . The method of  claim 15 , further comprising the step of reducing a height of the BOP control pod. 
     
     
         19 . The method of  claim 15 , wherein the at least one sub-pod comprises:
 a valve assembly, wherein the valve assembly comprises a solenoid, an electronics interface, and a directional control valve;   a modular valve pack, wherein the modular valve pack comprises a manifold, and wherein the manifold is operable to support the valve assembly within the manifold; and   a controller, wherein the controller is operable to control a state of the valve assembly for carrying out functions in the BOP stack, wherein the sub-pod can be docked subsea within the BOP stack, and wherein the sub-pod can be removed from the BOP stack subsea and replaced in the BOP stack subsea by an alternative sub-pod.   
     
     
         20 . The method of  claim 19 , further comprising the step of operating the controller to translate CANbus data from a central computer to solenoid functions. 
     
     
         21 . The method according to  claim 15 , further comprising the step of stacking multiple sub-pods disposed within the BOP stack.