With larger weights of subsea blowout preventers (BOPs) now being commonly used on fifth and sixth generation semi-submersibles and drillships, the issue of wellhead fatigue is becoming increasingly prominent.
The paper compares real-time measured and predicted wellhead fatigue performance in a deepwater drilling operation. It’s based on a real-time monitoring system that measured wave-driven fatigue at critical locations in a subsea well in the Mediterranean Sea.
Although the predicted fatigue life of the wellhead was approximately 255 days the drilling campaign was expected to last 290 days. Equipped with accelerometers and angular rate sensors, the monitoring system produced data revealing that the motions of the lower marine riser package (LMRP) and BOP in the well were considerably less than predicted which would result in a lower damage rate. This allowed drilling operations to continue for the full campaign term.
The conference paper describes the systematic identification of the factors contributing to the differences between the predicted and measured motions. It also defines areas where further research would be of value to help improve the reliability of analytically predicted fatigue lives.
Conference paper: Comparison of Real-Time Measured and Predicted Wellhead Fatigue Performance in a Deepwater Drilling Operation (OMAE2015-42107)
Date: Wednesday, June 03, 2015 3:30 PM - 5:30 PM
Location: Symposium 4, OMAE 2015