ASME B31 for two phase pipeline
ASME B31 for two phase pipeline
(OP)
Hi, I would like to know for incoming oil wells and gas wells, which are having two phase flow, will the pipeline be governed by B31.4 (liquid transport) or B31.8 (gas transport).
Thanks for the help.
Thanks for the help.





RE: ASME B31 for two phase pipeline
RE: ASME B31 for two phase pipeline
(I don't have 31.4 in front of me so I can't quote the paragraph). One thing is for sure - don't do a thing until everybody including the independent inspector's dog has signed up in blood. Also consider the intent behind the codes and how this ties into your service. Why are allowable stresses higher for pipeline codes? Fluids with low corrosion rates, low risk of damage due to location and burial etc.
RE: ASME B31 for two phase pipeline
- Count the wells that were permitted as oil and the wells permitted as gas and go with the one with the most wells.
- Calculate mass flow rate of liquids and gases from the two streams and go with the biggest mass flow rate.
- Calculate the sales value of the two streams and go with the one that contributes the most value.
B31.8 is more forgiving of liquid in gas lines than B31.4 is about gas in liquid lines so you might weight the decision in favor of gas.
None of these is "right" and none of them is "wrong". My approach would be to pick a justification, write a memo to file explaining the reasoning, and get on with it.
David
RE: ASME B31 for two phase pipeline
The answer is.... NEITHER.
B31.4 and B31.8 DO NOT even apply to gathering systems.
Notice the title of B31.8
Now check the scope.
How please explain how does B31.8 include "Gathering Systems" when it specifically denotes a difference between "Transmission and Distribution systems" and "Gathering Systems" in regards to the title of the code?
You will find similar wording in B31.4
If you have further doubts, you can check the legal requirements in the US, CFR Title 49, Parts 192 for gas and 195 oil pipelines here,
http://ec
Look at the Scope of each Part.
192 (Gas)
http://ecf
http://ecf
194 (Oil)
h
Gathering systems NOT INCLUDED.
Its not only your choice, you don't have to use any code except what is required by your company policy.
FOR OFFSHORE GATHERING SYSTEMS
DOT CFR TITLE 149 DO NOT APPLY
SEE MMS REGULATIONS
http://virtualpipeline.spaces.msn.com
RE: ASME B31 for two phase pipeline
You are more or less correct, but if housing moves in to encroach on a gathering system then 49 CFR 192 becomes applicable and if you did not build the system to a code then it is really expensive to retrofit to the code. This is happening a lot these days as groups of mobile homes set up on top of old gathering systems. I've done several over the last few years and by the time you do the calcualtions, take the system down for a new static test, and x-ray accessible welds DOT has forced you into actions that result in the pipe looking like it was built to a code.
There is no downside to building gathering piping to code, you have to have some basis for design decisions and B31.8 is better than most.
David
RE: ASME B31 for two phase pipeline
RE: ASME B31 for two phase pipeline
I know pleanty of privately owned gathering systems that just install pipe....whatever pipe... with a preference for dented pipe....NO DESIGN AND NO CODES... no hydrotest... no inspection... no corrosion control program, no nothing. Its really scarey how thin a wall thickness you can get with 100% smys and a little corrosion. Talk to them about code and you'll get run off with a shotgun.
http://virtualpipeline.spaces.msn.com
RE: ASME B31 for two phase pipeline
http://virtualpipeline.spaces.msn.com
RE: ASME B31 for two phase pipeline
RE: ASME B31 for two phase pipeline
http://virtualpipeline.spaces.msn.com
RE: ASME B31 for two phase pipeline
On the other hand an old GCNM line that was built with uncoated, dented, thin wall pipe was a major problem to bring up to DOT specifications. Nearly impossible in fact.
David
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: ASME B31 for two phase pipeline
BTW, would you want a DOT regulated pipeline operating at 2200 psi in your backyard, I've done that and I was still scared to death as that line went 200 yards from a high school....
RE: ASME B31 for two phase pipeline
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RE: ASME B31 for two phase pipeline
(Its strange that all the hot shot experts are able to redefine the scope of the Code and sit on the fence - leaving you on your own when you have to make a stand and say nuts. Funny old world).
RE: ASME B31 for two phase pipeline
http://virtualpipeline.spaces.msn.com
RE: ASME B31 for two phase pipeline
David
RE: ASME B31 for two phase pipeline
http://virtualpipeline.spaces.msn.com
RE: ASME B31 for two phase pipeline
RE: ASME B31 for two phase pipeline
The smart aleck answer to your question decastro is, "YES! If you design/build and permit to/under CFR 49 Part 194 / B31.4". They sure can. The solution (?)... you'd better have those valves, or apply for a variance and waiver beforehand.
So... that's what regulations and codes don't do for you.
http://virtualpipeline.spaces.msn.com
RE: ASME B31 for two phase pipeline
http://virtualpipeline.spaces.msn.com
RE: ASME B31 for two phase pipeline
The point.... do whats right because its right, not because of a rule
RE: ASME B31 for two phase pipeline
The old adage is horses for courses. Rescoping a thorough bred race horse to pull a cart might be possible if you know what you are doing. Then again, if you don't you might just get a damn good kicking and dragged through the s**t at high speed.
RE: ASME B31 for two phase pipeline
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