Subsea tree safety control system
AssigneeSchlumberger Technology Corporation
InventorDavid James Mathis
Life of this patent
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Abstract
An embodiment of a method for limiting the probability of failure on demand of a subsea test tree (“SSTT”) includes the steps of providing a safety shut-in system for actuating a safety valve of the SSTT, the safety shut-in system including a surface control station positioned above a water surface connected via an umbilical to a subsea control system positioned below the water surface to actuate the safety valve; and diagnostically testing the safety shut-in system without actuating the safety valve.
Claims18
A subsurface test tree system, the system comprising:
- a subsea test tree having a safety valve, the subsea test tree connectable with a blowout preventer stack below a water surface;
- a subsea control system operationally connected with the subsea test tree below the water surface to actuate the safety valve, wherein the subsea control system does not include a microprocessor;
- a surface control station positioned at a surface location, the control station including a microprocessor;
- and
- an umbilical operationally connecting the control station and the subsea control system to actuate the safety valve in response to a signal sent from the control station to the subsea control system.
A method for operating a subsea test tree (“SSTT”) that includes a safety valve, the method comprising the steps of:
- providing a subsea control system below a water surface in connection with the safety valve;
- connecting a surface control station to the subsea control system via an umbilical;
- and
- actuating the safety valve via DC actuation.
Dependencies are inferred from the claim text.