Wellhead or Christmas tree

[Jyop92]

Can anybody tell me why during shutdown operation it is always necessary to close the wing valve first followed by master and SSSV valve.Please provide me the detailed engineering about these.

 

[LittleInch]

The wing valve is then the one which takes all the effort and wear of closing against a moving flow. The wing valve is the easiest valve to replaceif it starts to pass.

Then master valve then SSSV.

SSSV are difficult to open with a pressure difference. If you close the SSSV first you can have a large pressure difference and then when your well tries to restart you might find it hard to reopen the SSSV.

Often SSSV is NOT closed unless you really need it.

Look up how an SSSV works and you'll realise why.

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