Bore Restriction on Pipeline

[Kene1]

We have completed laying a 12'' pipeline in swamp location and pre-commissioning activity is in progress. A caliper pig was launched on the pipeline after the gauge pig was observed to be badly distorted. The caliper pig showed bore restriction in 5 different locations and the contractor commenced repair work at the locations. Anyway, the client advised that work should be stopped until full investigation into the cause of the damage on the pipeline. Please advise on the steps that needs to be taken, thanks.

 

[LittleInch]

Not a huge amount you can do until you dig up the pipeline or at least work out where the restrictions are.

Depending on your pig you should be able to determine if the restriction is a smooth dent, sharp dent or buckle. If you can get a longitudinal profile out of the pig data then that might tell you what was happening.

Review any construction notes / photos / talk to the crews / inspectors if they're still around to see if they noted anything.

Then dig it up and have a look...

My motto: Learn something new every day

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

 

[racookpe1978]

I'm not familiar with the long-distance pipeline industry. Does anybody make a remote-control, through-pipe machining fixture that mounts on the front face of a pig?

 

[LittleInch]

racookpe -

maybe best as a new post, but no, I've never heard of anything that could easily cut a hole in a pipeline from the inside. There are a lot of wax removal pigs and other scraping devices, but not one which can remove metal AFAIK.

My motto: Learn something new every day

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