Sil rated system for blowout preventer control

Patent metadata

Field	Value
Publication number	US-10196871-B2
Application number	US-201715624414-A
Country	US
Kind code	B2
Filing date	Jun 15, 2017
Priority date	Sep 30, 2014
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A control system for a subsea blowout preventer (BOP) positioned in a lower stack, the lower stack releasably engaged with a lower marine riser package (LMRP). The control system includes a surface logic solver positioned at or adjacent the surface of the sea that generates commands for operating the subsea BOP, a first subsea logic solver attached to the LMRP and in communication with the surface logic solver so that the first subsea logic solver receives the commands from the surface logic solver, and a second subsea logic solver attached to a hydraulic control unit in the lower stack. The second subsea logic solver is in hydraulic communication with the subsea BOP, and the first subsea logic solver so that the second subsea logic solver receives the commands from the first subsea logic solver and implements the commands by activating the hydraulic control unit to operate the BOP.

First claim

What is claimed is:

1. A control system for a subsea blowout preventer (BOP), comprising:
a process controller;
a hydraulic pump in communication with the process controller via a first hydraulic circuit for providing hydraulic fluid to the subsea BOP to execute a function;
a hydraulic control unit containing a plurality of valves, each valve for regulating the flow of hydraulic fluid between the hydraulic pump and the subsea BOP;
a logic solver positioned at or above the surface of the sea that monitors the function; and
a control panel containing a plurality of valves, each valve for regulating the flow of hydraulic fluid between the hydraulic pump and the subsea BOP, the control panel connected to the logic solver and in hydraulic communication with the hydraulic pump and the subsea BOP via a second hydraulic circuit so that upon detection of an irregularity in the function, the logic solver can override the process controller and complete the function.

2. The control system of claim 1 , wherein the logic solver comprises a central processing unit (CPU).

3. The control system of claim 1 , wherein the system further comprises:
a human machine interface panel connected to the logic solver.

4. The control system of claim 1 , wherein the hydraulic control unit further comprises:
an autoshear to close the BOP upon failure of both the process controller and the logic solver to carry out the function.

5. The control system of claim 1 , wherein the process controller, hydraulic pump, logic solver, and control panel are located at or above the sea surface.

6. The control system of claim 1 , wherein the logic solver is positioned between the process controller and the hydraulic pump, and is in communication with both the process controller and the hydraulic pump.

7. The control system of claim 1 , wherein the logic solver receives flow and pressure data from the hydraulic pump to help monitor the function.

8. The control system of claim 1 , wherein the logic solver receives data about the pressure differential across the BOP to help monitor the function.

9. The control system of claim 1 , wherein the control panel includes components selected from the group consisting of solenoids and valves.

10. A redundant control system for a subsea blowout preventer (BOP) the control system comprising:
a process controller for controlling functions on the BOP;
a logic solver;
a first hydraulic circuit, comprising:
a master control skid with hydraulic pumps in communication with the process controller; and
a hydraulic control unit in hydraulic communication with the master control skid and the BOP, the hydraulic control unit having valves for regulating the functions of the BOP, each valve movable between an open and a closed position to control a function; and

a second hydraulic circuit, comprising:
the master control skid; and
a control panel having valves for regulating the functions of the BOP, each valve movable between an open and a closed position to control a function;

wherein the logic solver monitors the performance of the functions as carried out by the master control skid, hydraulic pumps, and hydraulic control unit of the first hydraulic circuit; and
wherein, upon detection of a failure of the performance of one of the functions, the logic solver initiates performance of the one of the functions by the master control skid, hydraulic pumps, and control panel of the second hydraulic circuit.

11. The control system of claim 10 , wherein the logic solver comprises a central processing unit (CPU).

12. The control system of claim 10 , wherein the system further comprises:
a human machine interface panel connected to the logic solver.

13. The control system of claim 10 , wherein the hydraulic control unit further comprises:
an autoshear to close the BOP upon failure of both the process controller and the logic solver to carry out the function.

14. The control system of claim 10 , wherein the process controller, master control skid, logic solver, and control panel are located at or above the sea surface.

15. The control system of claim 10 , wherein the logic solver is positioned between the process controller and the hydraulic pump, and is in communication with both the process controller and the hydraulic pump.

16. The control system of claim 10 , wherein the logic solver receives flow and pressure data from the master control skid to help monitor the function.

17. The control system of claim 10 , wherein the logic solver receives data about the pressure differential across the BOP to help monitor the function.

18. The control system of claim 10 , wherein the control panel includes components selected from the group consisting of solenoids and valves.

19. A method for controlling a subsea blowout preventer (BOP), the method comprising:
(a) generating a first command signal by a process controller located at or adjacent the surface of the sea;
(b) transmitting the first command signal to a master control skid having a hydraulic pump;
(c) transmitting a pilot hydraulic signal via a first hydraulic circuit to a hydraulic control unit in communication with the subsea BOP;
(d) monitoring the operation of the subsea BOP with a logic controller to determine if such operation is in accordance with the command signal;
(e) if the operation of the subsea BOP is not in accordance with the first command signal, generating a second command signal by the logic controller;
(f) transmitting the second command signal via a second hydraulic circuit to a control panel in communication with the subsea BOP; and
(g) operating the subsea BOP in accordance with the second command signal.

Assignees

• Hydril Usa Distrib Llc

Inventors

• Holmes John S
• Abou-Assaad Amine
• Milliman Douglas
• Huerta Luis

Classifications

• E21B33/0355 Primary

  Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads · CPC title

• G05B2219/25312

  Pneumatic, hydraulic modules, controlled valves · CPC title

• G05B2219/24015

  Monitoring · CPC title

• G05B19/0428

  Safety, monitoring (G05B19/0423 takes precedence) · CPC title

• E21B34/16

  Control means therefor being outside the borehole {(control systems for submerged well heads E21B33/0355)} · CPC title