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To:
Subject:
Ring Gaskets for subsea use
Question:
The project I am working on
has a requirement to mate a 2-1/6" API 5000 17SV flange with a
2-1/6" API 5000 17SS flange, sub sea. We will use the flanges to mate 2
Gas lift lines. I am looking for advice on the Ring Gasket I should use.
I have the idea that I should use a SBX 152, but I feel unsure about the
material type. If possible could you please recommend the correct
material and type of ring gasket for this application?
Answer:
Use a SBX gasket if you have to
"make-up" the connection while under water. If you make-up and
test the connection above the water you can use a BX gasket successfully.
The flanges you mention appear in API 17D.
This standard requires that the ring grooves have an inlay of Corrosion
Resistant Alloy (CRA). The “CRA” term does not have a clear
definition. Manufacturers may use 300 series Stainless Steel, or Inconel
625. In the view
of WOODCO USA, Inconel 625 performs the best because of both its corrosion
resistance and its resistance to deformation.
Most
users choose 316 SS gaskets when well conditions permit because they have
ready availability and reasonable cost.
For wells that produce extremely corrosive
fluids or gases, the control equipment may have the well wetted surfaces
completely overlayed with Inconel 625, and in this case Inconel 825 or 625 gaskets
seem mandatory.
This very general answer does not directly
address any particular well, producing any particular combination of
chemicals. A qualified "Consulting Materials
Scientist" (Metallurgist) familiar with Oil Field applications should
address particular well situations.
