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Marine Riser Analysis for DST's Operations
19 February 2015

I have been told that BP is running in addition to the Marine-Riser-Analysis (MRA) study (done before starting any drilling operations) a MRA also before running a DST. Honestly I can not understand the added value on doing that. Can anyone within the community advice if this is a common practice within the industry? A part of BP I have not heard anyone else doing it.

Many thanks in advance for any comment/advice

2 answer(s)
Senior Engineer
MCS Kenny
Total Posts: 2
Join Date: 25/12/12

The additional analysis should consider the following for DST operation:

  • Von Mises stress may change the limiting operating window of the equipment due to increased temperature/pressure encountered
  • Fatigue damage caused by changes in pressure and due to multiple cycles (it is not a concern due to the short period of operation)
2H Offshore Inc.
Total Posts: 2
Join Date: 19/02/15

The difference, in the Marine-Riser-Analysis point of view, between the Drilling and DST operation would be an increase in the internal pressure during DST operation.

For fatigue analysis It is not expected a significant change in the results, since it is a short duration operation.

For strength analysis, the increase of internal pressure could imply in a reduction of bending capacity of the wellhead connectors and consequently reduce the operational window.

To make sure the bending capacity of the connectors is not the most limiting criterion for the operational window, I would recommend to include sensitivity analysis of the DST operation in the drilling Marine-Riser-analysis.



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