Patent ID: 8978698
Filing Date: 2015-03-17
Classification: E21B,Y10T

Abstract:
1. A blowout preventer for sealing a tubular of a wellbore, the wellbore penetrating a subterranean formation, the blowout preventer comprising: a housing having a bore therethrough to receive the tubular; at least one ram slidably positionable in the housing, each of the at least one rams having a ram block positionable in sealing engagement about the tubular; an actuator to selectively drive the ram block, the actuator comprising a piston slidably positionable in a cylinder; and a monitor to detect the piston therein, the monitor comprising a visual indicator mechanically detached from the piston, and an electrical indicator comprising at least one proximity sensor, at least a portion of the visual indicator operatively connectable to the cylinder external to the cylinder, the visual indicator operatively coupled to the piston to display a position of the piston as the piston travels within the cylinder whereby a position of the ram may be determined.