Pigging of internally-lined pipeline 2

[ndeguy]

Ignoring the obvious statement, i.e. an internally-lined pipe should not be subject to corrosion and therefore inspection pigging is superfluous, can anyone tell me the maximum thickness of inside lining for MFL pigging inspection. Has anyone any experience of this?

Thanks in advance

Nigel Armstrong
Karachaganak Petroleum
Kazakhstan

 

[narenr]

Minimum thickness of CRA clad is 2.5mm, currently available tools do not magnetize through this thickness. IP vendors have not yet qualified nor developed a tool due to low market response as most OPCos do not IP CRA clad pipelines, but I am sure eventually they will. I learnt this as we have to perform IP and have an EPRS to meet statutory requirements.

Narendranath R
Pipeline engineering is made easy with state of the art computer software, visit

http://www.narendranath.itgo.com.

 

[SJones]

MFL should magnetise through the normal range of (organic) internal lining thicknesses of 0.3 - 0.5 mm. And, don't forget, pipe is also coated on the outside and it still corrodes!

As for CRA clad lines, I would expect that, when they come, the IP tools will be UT based rather than MFL.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[ndeguy]

Thanks for the replies, gentlemen.

With the organic linings could you tell me if there is a method for completing (applying) the protection of the pipeline afforded by the coating to the weld roots after welding. Or is that achieved by use of a specially-selected filler metal for the weld root?

Nigel Armstrong
Karachaganak Petroleum
Kazakhstan

 

[SJones]

Yes there is a method of internally field coating but, in my experience, if one is looking to use an internal coating as a reliable anti-corrosion measure this is one of the many areas with which it will all go sadly wrong. The method uses a robotic crawler with a magnetic locator similar to that deployed for X-ray radiography. I have to say that I've only seen it for FBE and it was a total shambles!

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[GregLamberson]

I'll echo SJones, trying to coat field joints internally is a nightmare. There are companies that do it and it's been done, but not successfully as far as I know.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com