Abstract: A riser tensioner has a cylindrical barrel and a piston rod that telescopingly engage each other. An external accumulator containing a hydraulic fluid and a gas is mounted outside of the barrels for communicating the hydraulic liquid to an end of the barrel. Depending on the stroke of the piston rod, the liquid level in the accumulator will fluctuate and the gas pressure vary. A composite rod within the accumulator is embedded with an array of PVDF sensors. The PVDF sensors provide an output signal to indicate the liquid level in the accumulator when the liquid comes in contact with the sensor, allowing for reliable monitoring of liquid levels.

Abstract: A riser tensioner has a cylindrical barrel and a piston rod that telescopingly engage each other. An external accumulator containing a hydraulic fluid and a gas is mounted outside of the barrels for communicating the hydraulic liquid to an end of the barrel. Depending on the stroke of the piston rod, the liquid level in the accumulator will fluctuate and the gas pressure vary. A composite rod within the accumulator is embedded with an array of PVDF sensors. The PVDF sensors provide an output signal to indicate the liquid level in the accumulator when the liquid comes in contact with the sensor, allowing for reliable monitoring of liquid levels.

Abstract: A wellhead assembly comprises an outer tubular wellhead member with a bore having an axis and a concentric inner seal surface, an inner tubular wellhead member for receiving an annular seal landed within the outer tubular wellhead member defining a seal pocket between them, the inner tubular member having a concentric outer seal surface, and a plurality of circumferentially extending, parallel wickers formed in at least one of the seal surfaces of the outer tubular and on the outer surface of the inner tubular. A profile of at least one of the wickers differs from a profile of at least some of the other wicker.