Enbridge failure - photos 2

[brimmer]

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...

 

[brimmer]

Attached photo

 

[ColonelSanders83]

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/

 

[brimmer]

I will try again, this site sometimes attachments work & sometimes they don't...

 

[brimmer]

The above worked, and the second photo because site won't let me attach 2 files in one posting...

 

[BigInch]

Makes me want to look for my hose clamps.

"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." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

 

[jte]

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

jt

 

[jmw]

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

http://www.ViscoAnalyser.com

 

[1gibson]

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.

 

[1gibson]

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

 

[BigInch]

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." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

 

[MJCronin]

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

 

[brimmer]

MJCronon, here is a link that has more info.

http://www.greendump.net/the-oil-dr...spill-some-clues-as-to-what-may-have-happened

Looks like a time dependent defect who's time came up...

 

[chicopee]

Overpressurization?

 

[DLite30]

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

 

[DLite30]

Man, I can't spell today.

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

 

[MJCronin]

"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

 

[MikeHalloran]

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


Mike Halloran
Pembroke Pines, FL, USA

 

[jmw]

Shades of Chernobyl.....?

JMW

http://www.ViscoAnalyser.com

 

[brimmer]

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