Hi Lajpat,
You have already stated the requirement for the Xmas tree - Max SIWHP is 6,000 psi , so you need a 10,000 psi tree on your well - simply because that's the next size up that will cover the requirement.
The next important bit is what the tree and its components are made of - you need to talk to your Xmas tree supplier to get the metallurgy right to combat the H2S and CO2 etc. in the well flow stream.
As for solid block or flanged, the choice is pretty much what is preferred, solid block trees are a bit more compact - less height - than the flanged type, however, if a valve needs repair/replacing, you have to change the whole tree. This could be a significant expense. On the other hand, the flanged type Xmas trees are higher, because of the flanges, but the valves changed be changed out individually.
The next important thing is to have a regular maintenance schedule for servicing the valves and ensure the materials used are suitable for the application, again your Xmas tree supplier should be able to help you with this.
I have yet to see/hear of a full bore rupture of a properly selected and maintained Xmas Tree, if you are worried about that, your well should be equipped with a Sub Surface Safety Valve, for that kind of well it should be mandatory.
Regards
Stuart Liddle
------Original Message------
Dear All,
Can anyone guide and share the experience of selecting the suitable type of X-mas tree as per operating conditions.
SIWHP ~ 6,000 psig, WHT ~ 250 degF. Produced gas ~ 50-60 MMSCFD. AOF ~ 110-120 MMSCFD.
Sand free produced fluid contains 20 PPM of H2S & 25 % of CO2, 50,000 chlorides.
From well integrity point of view, what type of X-mas tree (solid block or flanged) should be used for above operating conditions?
Is there any guideline or standards/regulations for selecting the X-mas tree specifically in worst case scenario (full bore rupture).
Regards,
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Lajpat Rai
Petroleum Engineer
United Energy Pakistan Ltd
Karachi City
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