Riser joint Vortex-Induced-Vibration (VIV) occurs while drilling in areas with strong ocean currents. This happens when a strong flow of water past a pipe creates vortices (turbulence) behind the pipe. These vortices then induce vibrations in the pipe, which can severely reduce the riser joints fatigue life, and also cause other damage to the riser system.
CDEX/JAMSTEC developed a real-time monitoring system, which measures and records riser pipe motion while drilling. This helps CDEX/JAMSTEC keep a running estimate of fatigue damage to each riser joint. VIV, and its’ damaging effects on the riser joints, can be mitigated and suppressed by adding riser fairings to riser joints directly in the current. Data collected during the NanTroSEIZE drilling project while deploying the riser fairing system has confirmed that VIV was fully suppressed, and therefore fatigue damage caused to the riser joints was extremely low.