Offshore oil and gas exploration is expanding into deeper and harsher oceanic environments, with extended drilling operations leading to increased concerns regarding wellhead and marine riser fatigue. Dr Killbourn’s paper outlines how monitoring can be used to mitigate these concerns and improve the understanding of riser behaviour in different current conditions.
The vibration of drilling risers due to vortex-shedding can impact on drilling operations and in extreme cases damage the riser or wellhead. A better understanding of the riser behaviour in relation to currents and vortex induced vibration helps to clarify the risks, leading to a better definition of the safe operating limits.
This will be demonstrated with the results of a study that recorded the motion of a deep-water drilling riser during a drilling campaign in the Norwegian Sea. To monitor vibration levels, four Fugro DeepData subsea motion pods were deployed, each containing a four degree-of-freedom inertial motion recorder. Two acoustic Doppler current profilers were also deployed to record current speed and direction at a range of depths.
The presentation will outline the frequency of the vortex-induced vibration that occurred at the well location and also explore the mode shapes and amplitudes of vibration.
Motion monitoring of a deep water drilling riser in the Norwegian Sea
Session 15E on 9th July: Oil and Gas