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Sub sea BOP testing
21 September 2018

When you are testing BOP with inverted bottom BOP in a deep water subsea BOP, how this affects the collapse rating of DP? . Here there are two factors affecting: 1. The pressure acting from out side, 2. The tensile loading of DP.  In other words the question is how the collapse pressure is affected with tensile loading combine with the pressure acting from outside. What precautions to be adopted?

3 answer(s)
Gulf Drilling
Total Posts: 3
Join Date: 21/09/18
Hi Yousaf and Steve,

Thank you very much for your responses amidst your busy schedule.

Highly appreciated.

Yes, I found it out from API Bulletin and from from casing design work outs. 

Once again Thank you very much.

Sr. Advisor, Well Engineering specialist Deepwater, ERD, HPHT & Special Projects
Chevron Corporation
Total Posts: 7
Join Date: 07/11/15

It is clearly afftecting the two factors
1- The pressure acting from out side on 
The tensile loading of DP.

collapse resistance is reduced by the tension (axial stress). For further more details refere to API Bulletin 5C3 Section 2.1.5.

I think this will help 
Welltrain Limited
Total Posts: 8
Join Date: 09/12/09
The DP collapse resistance is reduced by the tension (axial stress).   The process for de-rating the API minimum collapse pressure is described in API Bulletin 5C3 Section 2.1.5.

Essentially the axial stress reduces the available API yield stress that is one of the components of the Minimum collapse formulae.

If you need more help evaluating this please do not hesitate to contact me.

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