Patent ID: 8931567
Filing Date: 2015-01-13
Classification: E21B,Y10T

Abstract:
1. A control mechanism for use with a safety valve adapted to seal a well bore, the control mechanism comprising: at least one valve actuator for engaging with the safety valve, the at least one actuator being movable, in use, with respect to the well bore along an axis parallel to the well bore longitudinal axis, between a valve open position, in which the safety valve is open, and a valve closed position, in which the safety valve is closed; and biasing apparatus adapted to bias the at least one valve actuator to the valve closed position; wherein the at least one valve actuator is a shaft with a first end and a second end and extending from the safey valve to a wellhead, the wellhead having associated therewith wellhead equipment, the first end of the shaft being coupled to the safety valve, wherein the second end of at least one valve actuator is selectively engaged by an energising means to apply a downward force and move the at least one actuator from the valve closed position to the valve open position, the energising means comprising a load applied on the at least one valve actuator by the weight of the wellhead equipment on the wellhead.