Evaluation of Wellhead Fatigue Using In-Service Monitoring Data
14 June, 2012
Evaluation of Wellhead Fatigue Using In-Service Structural Monitoring Data
14 June 2012 London Evening Meeting
Chairman Dr Bob Allwood, Chief Executive, SUT
To conduct offshore drilling activities safely there is an increasing requirement to understand the strength and durability of subsea wellheads and conductors. The use of modern drilling rigs, with larger BOP stacks and drill-through trees, combined with longer well durations and multiple intervention operations is now producing far greater levels of fatigue loading on subsea wellheads.
The prediction of the fatigue response using numerical analysis can be conservative; often the allowable fatigue design limits are predicted to be exceeded before the target operation durations are achieved.
To improve the understanding of the fatigue behaviour of these systems, in-situ monitoring of the drilling riser and wellhead response can be used. This presentation discussed the use of a wellhead response monitoring program from a recent application in the North Sea. The measured responses obtained from the monitoring campaign are evaluated and compared with analytical predictions. Where differences are identified, these are investigated further. The applicability and implications of the findings for the refinement of wellhead fatigue predictions in other applications are discussed.