In an effort to more effectively understand and manage vortex-induced vibration (VIV) fatigue integrity of its drilling risers, BP has instrumented several of them on a number of mobile offshore drilling units (MODUs) and offshore production platforms worldwide. This paper presents several aspects of the findings from those monitoring campaigns, with particular emphasis on the relatively more densely populated MODU data sets. In-situ monitoring has practical use as a realtime quantifier of accrued VIV fatigue damage to both drilling riser and wellhead casing over the course of a given monitoring period, a fundamental indicator of structural integrity. At present, this can be very useful to operators given that the gap between predicted and measured VIV fatigue damage can be very large. In this paper, the measured data are used to expose some of the physical details of full-scale riser response whose omission from predictive design tools and methods may contribute to this wide gap. To characterize the size of the gap, the data are compared to calculations using the most commonly used industry VIV analysis software. This demonstrates the inherent level of analysis over conservatism with respect to full-scale, unsuppressed drilling risers in the field when typical analysis parameters are utilized. A means of adjusting the parameters to reduce the over conservatism is then implemented. Finally, the data are used to reveal some performance indicators for VIV suppression devices that are presently being utilized in drilling operations.

VIV suppression and drag reduction are key issues for improved operation in offshore drilling. Properly designed helical strakes are effective in the mitigation of VIV fatigue damage for many riser applications. However such strakes tend not to be applicable to offshore drilling riser applications. This is due to increases in drag force due to increased apparent diameter as well as workability problems for drilling operations. For these reasons, effective devices are sought that would mitigate VIV and reduce, or at least not increase, drag for drilling applications. Along with yielding good hydrodynamic performance, a drilling riser VIV suppression device must be compact and robust enough to be used in a drilling-rig environment. It needs to be deployable and recoverable in declared operational sea states. It must also be easy to store and assemble. Finally, and most importantly, it must be efficient to deploy and recover during normal riser operations. This last point is vital to drilling operations in deepwater in hurricane-prone areas. Weather conditions can change quickly and even a non-faired deepwater riser takes 2 to 3 days for a full retrieval. BP continues to research and document suppression device types and to assess their practical performance. A supply choice in the market place is important so that the correct device can be used for particular situations. To this end, we have recently worked with cooperative partners to demonstrate the hydrodynamic performance of a handful of the most promising devices. This paper is a tailored synopsis of previous suppression concepts and the philosophical pathway toward what is available on the market today. At its core are recent circumstances which precipitated a need to quantify and qualify for operational acceptance the performance of two commercially available short aspect ratio fairing devices. (i.e. a dual-fin splitter and an airfoil-shaped fairing). This paper discusses the results of the large-scale model acceptance tests over prototype Reynolds number for these devices. In addition to rigid devices, a relatively newer suppression product that “inflates” in the direction of the relative flow was also assessed by BP for expected hydrodynamic performance. This device shows particular promise for the mitigation of VIV during drilling operations surprises in high currents along with appearing potentially commercially viable.