FlexLock™ fairings were first deployed on deepwater drilling risers in 2016. The FlexLock design is significantly faster to install offshore than previous tail fairing™ designs and offers much better suppression and drag reduction than alternative buoyancy products. Both standard and FlexLock fairing systems consist of tails that are held against a riser with straps and maintain their position along the riser using thrust collars. However, unlike a standard tail fairing system, FlexLock offers the added benefit of being able to use multiple fairings between each collar. Adjacent tails are coupled together in a flexible fashion and permitted to rotate around the riser as a single unit. Typically at least one-half of the system’s collars are eliminated thereby saving valuable time offshore and substantially reducing the capital expenditure. Experienced crews can typically install a joint of FlexLock tail fairings in 30-45 minutes.
Suppression performance is also improved with the FlexLock design. The coupled fairings further reduce both VIV and drag relative to standard tail fairings. FlexLock fairings are particularly effective in high currents where boundary layers are already turbulent. By comparison, alternative buoyancy products show only minimal drag reduction in high currents because they do little to narrow the wake or reduce the spanwise correlation of vortex shedding. Our FlexLock tail fairings were recently used to drill a well in 2.5 knots of current offshore South America with great success.
The FlexLock design also incorporates improvements associated with VIV Solutions’ Generation II drilling riser fairings. Expensive CRA hardware has been eliminated and replaced with a quick-turn fastener that has been load tested to over 2,000 lbs. Customers remark that VIV Solutions’ fairings are easy to handle thanks to a 31% weight reduction over the previous design.
In conclusion, fairings remain the only proven choice for significantly reducing drilling riser VIV and improving operability. We have the knowledge and experience to customize our world-renown tail fairing products for your riser and implement the latest FlexLock technology to further improve installation speeds and suppression performance.