Drilling Equipment

Marine Risers Support Systems (Tensioners)

The riser connecting a floating drilling vessel to the sea floor must be supported to keep it from buckling. Buoyant chambers provide sufficient uplift to keep the riser constantly tensioned and permit it to be free standing when not connected to the drilling vessel. However, there was a risk that should the riser become disconnected from the seabed it would bob to the surface damaging the rig. Thus, the idea was to keep the riser at neutral buoyancy using flotation and support it using tensioners, In the mid 1960's, The Rucker Company introduced their hydro-pneumatic tensioner systems using hydraulic pressure to stroke multiple compensation cylinders as the drilling vessel moves up and down. The hydraulic pressure is powered by air pressure stored in accumulators. The air either expands or is compressed as the cylinder rods stroke in and out. Cables run from the rods over sheaves mounted under the drill floor and are connected to the top of the riser keeping it positively tensioned. This same technology is used on the majority of floating drilling vessels today.

Recognizing the pioneering efforts of the following people and companies who contributed to the development of this technology:

Douwe "D" de Vries, John W. Prud'homme, Aaron "Dusty" Rhodes, George Savage,
Global Marine (GlobalSantaFe),
The Offshore Company (Transocean Inc.),
Petroleos Mexicanos (PEMEX),
The Rucker Company (Shaffer a Varco Co.), Shell