Methods and apparatus for hydraulic and electro-hydraulic control of subsea blowout preventor systems

A kit for retrofitting a pre-existing all-hydraulic blowout preventer stack control pod to provide electronic control of critical functions, wherein the critical functions are controlled by hydraulically operated pilot valves, comprising:

• (a) a surface controller for transmitting electronic control signals;
• (b) an electronic control pod coupled to the all-hydraulic control pod;
• (c) one or more umbilical cables comprising a plurality of dedicated electronic control wires that extend from the controller to the electronic control pod;
• (d) wherein the electronic control pod comprises a plurality of direct operated solenoid valves in electronic communication with the controller through one or more of the plurality of dedicated electronic control wires, wherein each direct operated solenoid valve translates electronic control signals from the controller into hydraulic control signals that are in communication with a junction plate that is aligned for coupling with one of the hydraulically operated pilot valves controlling the critical function.

An apparatus for controlling a BOP stack, comprising:

• (a) a surface controller for transmitting hydraulic control signals and electronic control signals;
• (b) one or more umbilical cables comprising a plurality of control transmission carriers selected from hydraulic control lines, dedicated electronic control wires, and combinations thereof, wherein the control transmission carriers extend from the controller to an umbilical junction plate;
• (c) one or more retrievable control pod assembly comprising:
• (1) a pod junction plate that is selectively mateable to the umbilical junction plate;
• (2) a plurality of direct operated solenoid valves in electronic communication with the controller through one or more of the dedicated electronic control wires, wherein each solenoid valve translates electronic control signals from the controller into hydraulic control signals that are in communication with a hydraulically operated pilot valve to cause delivery of hydraulic fluid from a power fluid source to a critical function of the BOP stack;
• and
• (3) a plurality of hydraulically operated pilot valves that deliver hydraulic fluid from a power fluid source to a non-critical function of the BOP stack upon receiving a hydraulic control signal directly from the controller through the umbilical.

A method for retrofitting a pre-existing all-hydraulic blowout preventer stack control pod to provide electronic control of critical functions previously controlled by a surface controller connected by hydraulic control lines to critical hydraulically operated pilot valves, comprising:

• adapting the surface controller to transmit hydraulic control signals and electronic control signals through one or more umbilical cables to a retrievable control pod assembly;
• adapting the one or more umbilical cables comprising a plurality of control transmission carriers selected from hydraulic control lines, dedicated electronic control wires, and combinations thereof, to extend the control transmission carriers from the controller to one or more umbilical junction plates;
• replacing the hydraulic control lines from the surface controller to the critical hydraulically operated pilot valves with hydraulic control lines from outlets of a plurality of direct operated solenoid valves;
• and
• connecting the electronic control wires from the surface controller to the direct operated solenoid valves, wherein the surface controller transmits control signals through the electronic control wires to the direct operated solenoid valves, and wherein the electronic control signals command the direct operated solenoid;
• valves to send hydraulic control signals to the critical hydraulically operated pilot valves to cause delivery of hydraulic fluid from a power fluid source to the critical functions of the blowout preventer stack.