Fatigue damage assessment methodology for a deepwater subsea wellhead based on monitoring data

ABSTRACT

Deepwater subsea wellhead system is subjected to the various cyclic loads transmitted from the drilling riser due to ocean waves, currents and platform motion during drilling operation; therefore, the fatigue damage is accumulated. A fatigue damage assessment methodology and its detailed analysis procedure for subsea wellheads utilising transfer function theory based on monitoring acceleration data at the drilling riser are developed. Studies on an actual monitoring case for a subsea wellhead under drilling operation with 336 h of monitoring events are conducted and a verification method by comparison of the measured fatigue results and predicted fatigue results based on wave and current data are introduced. The results for wave and vortex-induced vibration (VIV) fatigue life based on measured acceleration data are calculated, and the fatigue bias with predicted results are summarised. The developed fatigue damage assessment method and monitoring case studies can be valuable references for deepwater drilling engineering.

KEYWORDS:

• Subsea wellhead
• fatigue damage assessment
• vibration pattern identification
• transfer function
• measured acceleration data

Acknowledgments

The authors thank the China University of Petroleum (East China) for their contribution to the research work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

This work is supported by the National Key Research and Development Program of China, High-tech Ship Research Projects Sponsored by MIIT [grant number CBG2N21-4-2-5] and Prospective Project of Deepwater Engineering Laboratory [grant number 2023-SSGC-ZZQZ].