Gas leak through a hole in the pipeline

[Iradah]

Hello all,

I need to calculate the flow rate of gas leak from a pipeline coming from gas well where some water and condensate are produced also. The leak is from 130 psig pipeline pressure to the atmoshpere. What is tbe best equation to use?

Thank you..

 

[zdas04]

The attached file describes the process. The hardest part is getting the area of the hole. I've used graph paper and cut out the shape of the hole, then overlaid the hole on graph paper to get an approximate area that I could convert to a diameter.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"

 

[zdas04]

I forgot to mention that you need to recalculate the mass flow rate for each pressure step (I recalculate for every psig step) and then calculate or estimate the time required between steps.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"

 

[LittleInch]

Maybe it's just me, but no leak is acceptable and you should be spending your time fixing the hole?? Unles sit's really small and at the top of the pipe you'll also be getting condensate spraying out from time to time.

Holes only ever get bigger in my experience...

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[SJones]

Steady on LI, it may be for a risk assessment. DNV-RP-G101 has some graphs and formulae starting around page 45

https://exchange.dnv.com/publishing/Codes/download.asp?url=2010-10/rp-g101.pdf

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[zdas04]

I had to do this kind of calculation for emissions reporting after an incident (and after fixing the leak).

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"

 

[Latexman]

I think Milton Beychok's website has some useful information.

Calculating Accidental Release Flow Rates From Pressurized Gas Systems

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.

 

[zdas04]

As usual, Milton did some very good work on that link. Thanks for including it. The equations I posted give very similar results with considerable manual intervention (those equations do not have a time component so you have to iterate manually).

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"

 

[LittleInch]

Ok, sorry, jumped the gun a bit. There are reasons to know what the flow might be or has been.

This is really good info.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[danw2]

Off topic, but the David's mention of sizing the hole with graph paper reminded me of how the electrochemists would determine the area inside the X-Y 'curve' from a polaragraph -

they'd trace the figure on graph paper, cutout the figure with scissors, weigh the paper on a lab balance and compare the weight to a chart they'd made from various weights of cutouts of 1 square, 2 squares, 4 squares, 9 squares, etc. The lab tech used a planimeter to calculate area for Y-t data, but the X-Y data area calc was like my sister making paper dolls.