Patent ID: 7329070
Filing Date: 2008-02-12
Classification: E21B

Abstract:
1. A tensioner assembly having a fully extended position, a fully retracted position and a plurality of extended positions therebetween, for supporting a riser extending downwardly from a platform to a subsea wellhead, wherein the tensioner assembly comprises: a tension disk connected to a riser conductor portion having a moveable guiding, stabilizing assembly for slidably engaging a first track and a second track attachable to the platform for preventing lateral movement of the tensioner assembly due to yaw, pitch, roll and sway of a vessel; a lower support structure for slidably and laterally supporting a plurality of hydraulic stroke cylinders; a plurality of ram tensioner piston rods wherein each of the plurality of ram tensioner piston rods engages the tension disk on one end; a cylinder deck securely supporting the first track and the second track and comprising a plurality of cylinder deck holes, wherein each of the plurality of cylinder deck holes has a diameter sufficient to enable slidable engagement with one of the plurality of hydraulic stroke cylinders; wherein the plurality of hydraulic stroke cylinders are slidingly secured to the cylinder deck on one end and to the lower support structure on the opposite end, and wherein the plurality of hydraulic stroke cylinders is concentrically disposed around the downwardly extending riser from the riser conductor portion, and wherein each of the plurality of hydraulic stroke cylinders is adapted for receiving one of the plurality of ram tensioner piston rods; a plurality of primary accumulators wherein each of the plurality of primary accumulators is connected to the cylinder deck and wherein each of the plurality of primary accumulators is in fluid communication with one of the plurality of hydraulic stroke cylinders in a one-to-one connection and wherein each of the plurality of primary accumulators has a volume dependant on a desired stiffness of the plurality of ram tensioner piston rods; a plurality of secondary accumulators, each in fluid communication with one of the plurality of hydraulic stroke cylinders in a one-to-one connection, and wherein each of the plurality of secondary accumulators is secured to one of the plurality of hydraulic stroke cylinders; a conductor fixedly secured to the lower support structure for slidably and removeably containing the riser from the subsea well; a plurality of valves, wherein each of the plurality of valves is disposed between one of the plurality of secondary accumulators and one of the plurality of hydraulic stroke cylinders; and wherein the tension disk can move from a fully retracted position to a fully extended position and a plurality of positions therebetween using the moveable guiding, stabilizing assembly engaging the first track and the second track and preventing lateral movement of the tension disk due to yaw, pitch, roll and sway of the vessel.