a cross river pipeline hydrostatic test. 5

[Faster7]

dears:
we have a pipeline 12" diameter and 1100 m length and it's crossing a river , sealed on two sides with a cap it's used as a backup for a main pipeline, it's unpigable (no pigging facilities) now we need it's not inspected before since 1999 now we need to inspect this line, and line wasn't put on service since construction.
is it ok to go directly to hydrostatic test, or we look for a technology for inspection first.
and what is the best choice for that.
the pipeline grade is X65 ERW (Electric Welded Pipe).

 

[alchemon]

You'll have to check your code. In my opinion, you might as well treat this as a new line and do all the commissioning you would do for a new install.

A potential commissioning process might include.

I'd recommend doing a "leak test" first: pressure test to planned operating pressure and see if there are issues.

Then run a "non-invasive pig", there are plenty of vendors out there that'll claim they their pig is designed to run through a non piggable line. They can likely bring in a mobile launcher/receiver to complete.

If you receive a clean bill of health from that, then hydrotest at full test pressure to substantiate desired MAOP.

If everything passes this, then install your permanent launcher and receiver.

 

[LittleInch]

I would be looking to make it piggable by connecting temporary traps at either end.

After 21 years it could have suffered considerable external or internal corrosion. So it might pass a hydro test, but then fail 6 months later. Hydro tests sometimes fid it difficult to find pin hole leaks, but you'll find out fairly quickly once you put it into service, especially liquid service.

If you haven't done so I would also do a surface inspection if you can of the river bed and or sonar to see if its still buried.

Once you get access to the pipeline magnetic metal loss detection is probably easier to do as you can do it in air.

Has it been protected by CP?
What's the coating?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

ASME B31.4 or .8 do not require an intelligent pig inspection (IPS), that's an ops/maintenance function, so its your call to do it or not.

Personally, I would inspect the crossing for proper burial depth, ie. no washout of river bottom, then do the leak and hydrotest without IPS. The hydrotest is proof enough for use and you must do that one way or another before putting it into service.

If you install the pig traps, you can do an IPS anytime, before or after. Why hold up construction and operations waiting for a IPS contractor.

 

[LittleInch]

I agree its not "required", but this is a really long time between installation and operation.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

I'm not saying an IPS wouldn't be a good thing, if you have the time to spare and all. but the hydro is required. First things first.

 

[alchemon]

I'd run a caliper type pig at minimum before hydrotesting. Would at least show if there's been any internal corrosion. A frac out during hydrotest could be a big issue if it were in the wrong spot and within the domain of the wrong environmental agency.

 

[1503-44]

That basically for detecting dents and ovaling. It certainly won't catch pinholes and laminations, or weld cracks. Imo, of very limited usefulness for strength test. It won't really give you enough info to evaluate integrity. If you're going to go to the trouble of running a pig at all, run a smart one. 80% of the work involved is the same.

 

[Faster7]

Vrey helpful discussions thank you all

 

[Faster7]

Unfortunately no CP applied.
And The coating is 3LPP.

 

[LittleInch]

Look, it's probably fine to use though would be better if it had CP applied.

A hydro test will tell you if it's good to use or not at this time but not give you any idea if it will be good after 1 year or 5 years.

At 1100m I would be tempted to use a crawler pig or tethered inspection pig to give me that assurance.

But it's all down to what your risk appetite is.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

3LPP is good stuff if it was not damaged during or after installation.

What is inside? Air? N2?

I'm thinking you could go for a long leak test at around half test pressure and if that holds, go for full test.

 

[BenMacier]

If it's a backup for an existing pipeline, it was aimed to stay clean (was it sealed properly?) and undamaged for the same lifetime as the main pipeline.
Avoiding any inspection, even basic visual, before putting it into service is looking for troubles.

Is there access from both ends? If so, then run a camera. It's only about 1km long.
When you will deal with a 1000 km pipeline single section (Turkish stream, each of the 4 subsea gas pipelines), then we can have a serious discussion on what testing can be done.

* Finding a solution is great * Knowing how to implement it is fantastic * Believing it is the only one and best is naive ?

 

[LittleInch]

Well basically this is about a Management of Change (MOC) operation.

So follow the same principles here:
Assess the information you have.
Identify gaps
Identify risks
Determine what you can do to fill in the gaps.
Most importantly - get someone with authority to approve it.

Realistically your biggest worry after 22 years at the bottom of a river is what is the depth of cover / is it exposed on the river bed?

After that it's external corrosion and an internal camera inspection won't tell you much unless its eaten all the way through.

First off see if there's a big hole - pump it up with air to say 2 bar and leave it for a week. If its still 2 bar then you at least know it's worth doing some more inspection on it and there isn't a massive hole in it somewhere.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

I was browsing my download folder when I found this one.