Top tensioned riser system performance is governed by various factors such as environmental conditions, vessel motions, and operational conditions. TTR consists of fatigue critical regions along the riser such as the keel reaction point at keel joint, lower stress joint and, and riser tensioner attachment locations, all of which may experience high stresses and high levels of fatigue damage. The fatigue loading resulting from vortex induced vibration (VIV) is significant and is often identified as a critical design driver. In addition, the riser motions are transferred along the conductor pipe to the fatigue critical first conductor connector beneath the mud line.
Riser monitoring provides a means of assessing ongoing riser integrity, assist operational decisions, optimize inspection, maintenance and repair (IMR) schedules and procedure and calibrate design tools.
Benefits
- Monitors the complex dynamic response of the riser
- Monitors fatigue resulting from riser VIV, wave and floater motions require multiple monitors along the riser
- Fatigue critical areas such as keel joint and tapered stress joint are monitored using individual monitors mounted on these special joints, and are typically high precision motion sensors to capture all the loading ranging from daily environmental loads to maximum loads during extreme events
- Conductor fatigue integrity can be monitored based on finite element extrapolation of tapered stress joint measurements
- Tensioner attachment location exhibits high curvature and direct strain measurement is considered more suitable
