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Enbridge failure - photos
2

Enbridge failure - photos

Enbridge failure - photos

(OP)
Thought I would post these photos of the Enbridge pipeline failure in Michigan. Full rupture, not a leak. Does not look like corrosion, but possibly SCC (or something else). Time will tell...

 

RE: Enbridge failure - photos

hmmm, photo seems to be missing, care to try again?

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!  

http://www.ap-dynamics.ab.ca/

RE: Enbridge failure - photos

Classical fishmouth. Looks as though it failed just below the longitudinal seam, probably in the HAZ?

jt

RE: Enbridge failure - photos

Is this a heavy crude that is cut back with distillates to meet pipeline density and viscosity limits?

What happens if distillate supply fails, can pumping pressure rise and expose a weakness?
I'd guess the online sensors would catch any high viscosity and if they didn't, the pumps would have safety bypasses to prevent excess line pressures and I would also guess that if the safety bypass failed the max pump pressure ought to be within the safe working pressure of the pipe....

....but then if everything was as it should be there'd be no accidents...
 

JMW
www.ViscoAnalyser.com

 

RE: Enbridge failure - photos

Lack of distillate, SG would rise slightly but viscosity would rise significantly, reducing pump efficiency and head. That should more than compensate for the SG change, and end up with lower pressures.

RE: Enbridge failure - photos

Nevermind, shutoff head would not have the viscous correction so you would see an increase!

RE: Enbridge failure - photos

Lose the distillate and slug your line with hi viscosity fluid and you can bet your bottom doller that pressure will go up.

You'd normally have a high pressure discharge control valve, a safety relief downstream of that, plus PT connected to the pump shutdown switch, unless the pipeline was designed for a pressure profile with inlet pressure equal to maximum pump shutoff pressure.

"The top of the organisation doesn't listen sufficiently to what the bottom is saying."  Tony Hayward X-CEO BP
"Being GREEN isn't easy." Kermitfrog http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

RE: Enbridge failure - photos

Are there any details of the piping MOC, pressures, temperatures, piping diameter etc ??

   

RE: Enbridge failure - photos

Overpressurization?  

RE: Enbridge failure - photos

Good old fashioned coating disbondment/failure, and subsequent loss of cathoic protection = corrision.

RE: Enbridge failure - photos

Man, I can't spell today.

Good old fashioned coating disbondment/failure, and subsequent loss of cathodic protection = corrosion.

RE: Enbridge failure - photos


"The pipe in the affected segment was manufactured by Siderius in 1969 and is constructed of 3O-inch x 0.250-inch wall thickness, grade X-52 submerged arc weld pipe"

30 inch pipe is longitudinal seam welded.....was the failure along the axial seam weld ?

Although the fish mouth failure points to the conclusion of pressure surge,.....IMHO.....its not a "good enough" fish mouth, if failure occured at the weld seam.

-MJC

   

RE: Enbridge failure - photos

Sounds like repeated "false positive" overpressure warnings were not actually false.
 

Mike Halloran
Pembroke Pines, FL, USA

RE: Enbridge failure - photos

(OP)
Looks like a toe crack to me... (in HAZ below seam)

RE: Enbridge failure - photos

They may want to also review the SCADA data for valve position events- a sudden closure of a valve on the UG gasoline pipeline in Bellingham Washington 10 years ago led to the waterhammer pressure surge on that 100 mile long pipeline, pipe failure , multiple fatalities. That valve closure was due to the not-so-bumpless transfer that occurred when the backup DCS was switched on, causing valves to fail closed.

Of more interest is the planned 2500 mile long crude oil line planned from the tar sands to the vancouver island terminal- I can only guess at the overpressure that would occur if a valve slammed shut on that beast.

RE: Enbridge failure - photos

correction:

The Enbridge Gateway project is only 1150 km ( plus 1150 km return for recycled distillate) .

RE: Enbridge failure - photos

In the photo, the left end of the split looks to be a brittle-type crack.  It 'wanders' a little too much to be only a pressure-related birdmouth.  Perhaps a toe-crack from the seam HAZ, possibly started from enviromental Stress Corrosion Cracking on the ID.  I also agree that there probably were pressure transients that might have been up to Waterhammer force, and not properly evaluated while they were occurring.  Half the mass [weight] of a cylinder of heavy crude 30" in diameter, several miles long times the flow velocity squared is an incredible ammount of energy.  Very easy for it to overstress 1/4" 1960-vintage steel.   

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