Allbrown Universal Components (AUC) has recently completed a challenging application for its VIV Suppression system based on the AUC strake design.

The application was for a 30 inch diameter conductor deployed at the Tangguh offshore site in Indonesia, an area is well known for the presence of ocean currents.

The challenges were for the strakes to survive the driving process of the conductor as well as passing through a restriction which reduced the overall diameter to 33 inches.

The driving process delivers high shock loading to the conductor so that any appurtenances (strakes in this case) must be fixed in such a way to be unaffected by these high impact forces.  This is achieved by making sure that the banding forces are applied radially to the point where it traverses the strake and not circumferentially, which would spread the applied tension over a greater area.  Additionally, the reduced weight of the strake minimises inertial forces generated by the shock loading and transmitted to the system.

The Allbrown strake design is manufactured from a flexible elastomer which will allow the strake to collapse and reform during its passage through the guide restrictions. The strake design easily withstands a collapse ratio of over 50 % without exceeding the modulus of the strake material.

Photographs show the assembly of the strakes at the shore base in Sorong, straked conductors being handled through the “V” door, straked conductors in lay down area on drilling rig and straked conductors being driven on rig floor.

Allbrown provided full-service engineering support, supervision and advice for assembly and for all aspects of transporting the straked conductors offshore without any damage sustained. Allbrown also supervised final deployment of conductors on rig and into their service elevation in the water column.