pipeline lifetime
pipeline lifetime
(OP)
It's a general question.
I was reading the design basis of the factory working there and I encountered the following Sentence :
... the design life of the pipeline is 25 years.
and also I know that corrosion inhibitor is injected to the pipeline continuously.
One of the my colleague says that corrosion inhibitor injection has not any credit to lifetime of pipeline and without the injection the pipeline lifetime should be 25 years. Of course he said that this subject is applicable for any pipeline. Is He right? the pipeline is 10 km sour crude oil with 50 barg pressure.
Thanks in advance.
I was reading the design basis of the factory working there and I encountered the following Sentence :
... the design life of the pipeline is 25 years.
and also I know that corrosion inhibitor is injected to the pipeline continuously.
One of the my colleague says that corrosion inhibitor injection has not any credit to lifetime of pipeline and without the injection the pipeline lifetime should be 25 years. Of course he said that this subject is applicable for any pipeline. Is He right? the pipeline is 10 km sour crude oil with 50 barg pressure.
Thanks in advance.
RE: pipeline lifetime
You also may see design life related to EQ design. This about owner's and public risk and does need mean you need to shut the line after 25 years.
RE: pipeline lifetime
Actually i want to know injection of corrosion inhibitor how long )approximately can increase lifetime the pipeline? what is the relation between injection and life time of pipeline?
RE: pipeline lifetime
Lifetime depends on the expected corrosion rate given your method of resisting it.
Sour crude can be extremely aggressive on bare steel, in some cases eating just the bottom of the pipe, or welds, ignoring extra wall thickness of the rest of the pipe.
If you have hot salty sour crude and bare steel walls, your pipe may not last 1yr, or it may last 2 or 3, or 5. So it depends on how aggressive the crude is. With the right inhibitors and dosage, it may last 5yr, 10 or 25.
What is the stream analysis, temperature and your treatment program detail?
RE: pipeline lifetime
Your colleague is an idiot.[IMHO]
If the design life is 25 years, then in the design when the corrosion rate is calculated, they will take into account the beneficial impact of the CI - usually 90 or 95% "effective" and calculate the required corrosion allowance from there.
No CI, no protection - lots of corrosion - leak within 3-5 years.
The calculations they do are not to be taken as gospel - corrosion can occur in isolated locations and result in leaks and it's not a uniform thing.
A few years ago some idiot on a working oil field worked out that they could stop injection of CI for 5 years, allow the pipeline to corrode down to nearly min wall thickness, then start again. "saved" a small fortune in CI, the person moved on and in less than 5 years, the gathering system started springing holes everywhere. They ran an intelligent pig and there was serious metal loss all over the place - result, reduced operating pressure, reduced throughput and a very expensive repair and replacement program many times the "saving" from not injecting CI.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: pipeline lifetime
I am working on offshore platform and in one of the field there is a 28 inch pipeline from offshore platform to transfer the almost 100,000 BPD crud oil to the Island. This pipeline is in service from 1975 up to now.(45 rears). In a 20 recent years (from 2001) due to failure of C.I system there isn't any injection to the pipeline and no problem has been reported respect to this pipeline.. The length of pipeline is 140 km.
RE: pipeline lifetime
The point is to know why CI is being used. Sweet dehydrated Crude oil or even with water up to 20% that flows reasonably fast will have very little internal corrosion. Practice and knowledge of corrosion in the 1970's was a lot lower than now and the use / injection of CI was seen a "standard practice". Nowadays you only add it if you need to to inhibit corrosion from something like CO2 or H2S.
Lots of corrosion is in isolated locations with pitting and can take many years for leaks to occur. Unless you're checking internal corrosion using intelligent pigs then you are just flying blind.
The design of the CI is usually to use up the Corrosion Allowance of 3-4mm max in the design life, so you still have design wall thickness left. In reality you use up the CA plus maybe 60-70% of your design wall thickness before you get a pinhole leak.
But if you're into 1-2mm/yr corrosion uninhibited then you have not a long time, especially if i't fairly thin pipe. Your 100000 bbl/day pipe is probably ~24" and 15-20mm thick? A 12" 8mm thick pipeline will corrode faster.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: pipeline lifetime
RE: pipeline lifetime
RE: pipeline lifetime
Just because one pipeline survives doesn't mean the other one will...
Your colleague is still wrong.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: pipeline lifetime
RE: pipeline lifetime
My guess is that's about 1-2 mm/Yr without CI.
With CI is about 0.1mm/Yr.
So yes, you can avoid CI for quite a long time, but your pipeline is unlikely to get to 25 years life.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: pipeline lifetime
This is all a task of risk management.
After all most equipment does not have a finite life.
It has a point in its life where the risk increases.
Then you begin inspecting more carefully, and more often.
And likely also do more frequent maintenance.
And at some point the risk and/or cost of repair exceed what is acceptable and you replace it.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
RE: pipeline lifetime
It seems that the operations of these piping systems are deviated from the engineering design conditions. IMO, no matter who said okay in the past, you may understand it to be a potential safety issue, and if any alternative to correct it.
RE: pipeline lifetime
RE: pipeline lifetime
To know if your friend is right or wrong, you have to go back and look into the design basis by the EPC to find out the criteria for the wall thickness calculation. If they have considered the impact of CI for determining the CA.
We also know that the design life is not a cast and stone when it comes to actual life. It's a parameter for designing the pipeline. You must be having an integrity program to assess the pipeline. Usually, customers like you will run a in-service FFS and decide to run/repair or replace the line.
GDD
Canada
RE: pipeline lifetime
The relationship between inhibitor injection, and the remnant life of the pipeline, is the reliability of the injection process. Also, why focus on inhibition? What about coatings, for example ? Remnant life isn't only driven by the inside environment.
Steve Jones
Corrosion Management Consultant
www.linkedin.com/in/drstevejones
All answers are personal opinions only and are in no way connected with any employer.
RE: pipeline lifetime
"You can internally coat a pipeline to resist your corrosive chemicals. In some cases you might need to do 2 or more methods."
RE: pipeline lifetime
Steve Jones
Corrosion Management Consultant
www.linkedin.com/in/drstevejones
All answers are personal opinions only and are in no way connected with any employer.