TECHNOLOGY FROM EUROPE

Big cylinders for big offshore rigs

Hydrowa B.V. manufactures some of the world’s biggest cylinders. Several of these cylinders are destined for the rig Stena Tay, located in the Gulf of Mexico. The rig can drill 10 km (6 mi) into the seafloor and can operate in water depths up to 2,400 m (7,825 ft).

The Stena Tay riser / drill pipe handling system.

For this rig, Hydrowa first delivered three lift cylinders for riser and drillpipe handling. These lift cylinders can move 1,500 t over 18 m with a maximum speed of 1 m/sec. By leading the heave cables over a pulley, they can transport a 750-t load over a distance of 36 m (117 ft) with a maximum speed of 2 m/sec. A riser-tube segment weighs about 25 t.

Further, this delivery includes a heave-compensation system at the riser position. These cylinders guarantee that the riser remains fixed and vertical as the rig heaves in three directions with the waves. These riser-compensation cylinders have a maximum stroke of 15.3 m (50 ft) and are fitted with a HYPOS stroke-length measuring system. This measuring system is integrated in the metal-oxide piston-rod coating, ALTIOX 300.

An electronically controlled compensator, comprising passive and active cylinders, was delivered for the drillstring heave compensator. These cylinders guarantee that the drillbit can apply constant force, despite platform movement.

The company also delivered several cylinders for the knuckle-boom cranes and other riser-handling equipment. The company currently has cylinders for the next-generation rig, Stena Don, now being built. With this follow-up order, the lift cylinders will also be supplied with the HYPOS stroke-length measuring system for active compensation.