Trelleborg launches helically grooved drill riser

Trelleborg has introduced a new-style drill riser buoyancy module that provides critical uplift to marine risers.

The helically grooved system significantly reduces drag and flow-induced motion. Validation test results indicate that the performance is equivalent to fairings, but at a fraction of the total operational cost.

Antony Croston, business group director with Trelleborg's offshore operation in Houston, says: «We reached a major milestone last year when testing results revealed that, when using the patented helically grooved buoyancy design, vortex induced vibration is effectively eliminated in high currents, with the added bonus that drag loading on the riser is also reduced to a level comparable with fairings.»

«For many years, fairings have been accepted as the best technical solution for drag and VIV reduction on drilling risers. Their use has come with an operational penalty in the form of increased running and retrieval time, as well as handling issues, especially in harsh weather. We now have an integral concept, which has been proven to match the performance of fairings, without any issues in drilling riser handling and running methodologies.»