Offshore systems (e.g., in lakes, bays, seas, oceans etc.) often include a riser which connects a surface vessel's equipment to a blowout preventer stack on a subsea wellhead. Offshore systems which are employed for well testing operations also typically include a safety shut-in system which automatically prevents fluid communication between the well and the surface vessel in the event of an emergency, such as when conditions in the well deviate from preset limits. Typically, the safety shut-in system includes a subsea test tree which is landed inside the blowout preventer stack on a pipe string. The subsea test tree generally includes a valve portion which has one or more safety valves that can automatically shut-in the well via a subsea safety shut-in system. Traditionally subsea safety shut-in systems provide that safety valves fail as-is in case of electric power failure for example. The traditional subsea safety shut-in systems further comprise systems and methods that may not provide a desired probability of failure on demand level. It is a desire to provide a system and method for providing a desired level of failure on demand.
USPTO Backgrounds
USPTO Backgrounds