Severe pipe damage 2

[zengx]

We are Constructing a 230 km buried pipeline. The pipeline is completed and hydrotested.
During the perming, one of the loaders hit the pipe, leaving a severe damage in the pipe, as shown in the attached picture.

I recommended to remove a 2 meters length of the pipe, and weld a new pup piece.
Since the new welds cannot be hydrotested (easily), i recommended to go for both RT (D4 film) and manual shear UT. The RT is to be supervised and interpreted by NDT level 3.

Any suggestions are welcome.

Mohammed Diab.
Inspection Supervisor - Saudi Aramco.

 

[zdas04]

I'd cut out a bigger chunk to make sure that I didn't end up making a weld in the HAZ of the weld that is taped.

Other than that I'd just x-ray the new welds. This kind of repair is relatively common and I've never heard of anyone hydroing a 230 km line for a repair weld. Doing a UT (or mag flux or die pen) wouldn't hurt anything, but doesn't add a whole lot either. In this situation I just x-ray.

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.

 

[DLite30]

Make sure you're replacement piece of pipe is already hydrotested.

 

[DLite30]

"Your" dang it...i swear my grammar skills get worse and worse the more time I spend on forums.

 

[zengx]

Thanks guys.

Mohammed Diab.
Inspection Supervisor - Saudi Aramco.

 

[trashcanman]

Be sure to replace the loader to prevent further damage.

 

[zengx]

Already done!

Mohammed Diab.
Inspection Supervisor - Saudi Aramco.

 

[SNORGY]

My approach would be to replace the entire joint / segment, be it single random, double random or triple random length. The money is in the welds, and you need two of them anyway.

 

[zdas04]

That approach maximizes the factory coating going into the ground which is a good thing. When I've done that I've left a meter or so of pipe on the damaged joint and cut a corresponding amount off the next joint. That way you only have one weld that is moderately close to the existing welds.

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.

 

[11echo]

"What IF" you got a 10ft length of pipe of equal grade, that was approx. 6" large in diameter then the pipeline, and made a "split sleeve" with a couple of 1 1/2" threaded couplings, one as a vent the other as a drain. You could repair the spot on the pipeline, weld the split sleeve over the repair, hydro-test the split sleeve, and once that passed pump grout in the annulus of the sleeve to permanently seal it up. FYI …I've seen this done on a major pipeline that was in operation.

 

[zdas04]

But why would you do that pre-commissioning? They can cut out a section, weld it in and not impact the MAWP of the pipeline at all. Once a pipe is in service, the rules change dramatically and split sleeve repairs can be an option (among others), but all of them are stop gap and no one trusts them for the life of the line.

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.