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Well control Equipment Packing units and Rubbers
29 January 2020
How often do you change rubber parts for BOP Stack ?! Is there any reference or document speaking about it please ?!
4 answer(s)
Augusto
Consultant [retired Shell staff]
SPREAD Associates
Total Posts: 269
Join Date: 02/09/05
I believe you have to look at the complete life cycle, starting with the purchasing guide lines  buy the fittest and not necessarily the cheapest. Selection of the elastomers manufacturer. Is it the Key. Original Equipment Manufacturer? Do they volunteer a suugested life expectancy? Do they offer other meaningfull advice?
STORAGE is the major drawback, in general the rigs store the tyres in the dark and BOP rubber spares under the sun, curtailing the life of the elastomeric materials. These should be in sealed envelopes with inert gas, kept in the dark at low temperatures.
DURING their use we can increase their life span by flexing the rubber, by closing on a larger diameter - anular seals, for instances - and to the pressure really required and not to the rated pressure of the preventer installed.etc.
Some papers of eventual interest
IADC/SPE 22452 Elastomers fit for drilling fluids by Hydrill
OTC 6583 Ekastomers for drilling in cold climats
CEA 39 Behaviour of sealing elastomers
PEA-77 Elastomer seal performance CAPCIS
SPE/IADC 21960 Conoco┬┤s elastomeric performance
MERL Materilas Engineering Research Lab
NACE Standards



Boumezrag
Drilling supervisor
Sonatrach Petroleum Corporation
Total Posts: 9
Join Date: 11/02/16
Hello Abdellah, My answer would be more about rig practices. We usually take a visual inspection for the packing elements of the rams and the packer of the annular. Moreover, as far as the annular preventer is concerned, if you increase the annular pressure more and more to have a positive test ( usually it s arround 700psi); that means the packing element is worn. The regular tests on the rig (once a week for exploration and once in 15 days for development would give an idea about the stat of the BOP)
Augusto
Consultant [retired Shell staff]
SPREAD Associates
Total Posts: 269
Join Date: 02/09/05
The elastomers are a very difficult client to the point that years ago it was not considered an engineering material,
There are useful selection guidelines such as E&P Forum (London), PEA, API 6A and of course the useful guidelines offered by the different Oilfield Equipment  Suppliers (Cameron, Shaffer, Hydrill and Koomey at the time).
The major hurdle: the Original Equipment Manufacturers - OEM - often sub contract the elastomer elements and that can be a source of headaches even with Custom moulds. Curing is also
a challenge.
In my experience only a permanent dialogue Operator, BOP suppier and Elastomer designer can ensure proper choice of materials fit for purpose,
Elastomer tolerancing, shelf-life, ageing, swelling or shrinking (forcing the use of anti-extrusion devices) and exposure to fluids (drilling or completion ; liquids - chemical ,gasses need a scrutiny that not everybody can master.
Even the most mundane storage is neglected: tyres are kept in the dark with air conditioning and the elastomers are exposed to the elements, at list while delivered to the rig awaiting installation.
So discuss the issue - in depth - with your OEM and beware of elastomers from copy-cats, apparently - I repeat apparently - cheaper.


Augusto
Consultant [retired Shell staff]
SPREAD Associates
Total Posts: 269
Join Date: 02/09/05
https://www.researchgate.net/publication/224120380_Useful_Lifetime_Prediction_of_Rubber_Components_U...Rubber material properties, and useful lifetime prediction and evaluation are very important in the design procedure to assure the safety and reliability of rubber ...
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