Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
(OP)
Hi,
I am currently working on a project in which the default option is a pipeline with internal CRA lining. We believe that this option is excessively expensive, so are looking to recommend that a carbon steel pipeline be constructed instead. To answer this question I am looking for guidelines or studies that may help in deciding whether we could in fact use just carbon steel. Is anybody able to suggest sources of information regarding cost differences of different pipeline materials (upfront, and ongoing maintenance costs), where different materials are appropriate or any particular case examples of where carbon steel pipelines are used (also ideally with operating conditions).
Kind regards,
Daniel
I am currently working on a project in which the default option is a pipeline with internal CRA lining. We believe that this option is excessively expensive, so are looking to recommend that a carbon steel pipeline be constructed instead. To answer this question I am looking for guidelines or studies that may help in deciding whether we could in fact use just carbon steel. Is anybody able to suggest sources of information regarding cost differences of different pipeline materials (upfront, and ongoing maintenance costs), where different materials are appropriate or any particular case examples of where carbon steel pipelines are used (also ideally with operating conditions).
Kind regards,
Daniel





RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
It's all about what belief is held in the corrosion prediction model employed, the risk tolerance of the owner, the quality of the lifecycle costing and the faith in being able to run a tight corrosion control programme.
http://www.nickelinstitute.org/TechnicalLiterature...
http://www.iso.org/iso/home/search.htm?qt=15663&am...
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
Sometimes CRA is necessary on a particular project. The next project grabs that file and sees that CRA might be useful. After a few generations of this, no one knows why your construction costs are so high and no one remembers why the CRA is required. Requirements for a particular project can generally be adjusted.
David Simpson, PE
MuleShoe Engineering
Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
calculate your corrosion rate, carbon steel life and then how many times you will have to make replacements. Calculate the replacement costs for the carbon steel during the entire system lifetime. For example, if you have a well that is only expected to have a 5 year lifetime and need only a short pipeline, carbon steel pipe with a corrosion allowance might be the way to go. If the well is expected to last 20 years, or your pipeline is long, you're going to need to replace it 4 times.
you must get smarter than the software you're using.
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
To give a little more context: I have a background in chemical engineering, however I am currently working as a management consultant for an O&G operator. Consequently, I am not necessarily trying to perform rigorous technical engineering calculations, but rather trying to demonstrate to my client that carbon steel may be better economically. They did of course do some analysis before settling on CRA pipes, however they have a history of building things to a much higher standard than required, consequently overspending on CAPEX. Of course it may turn out that CRA pipe is required due to field conditions, however I want to open them up to the idea of increasing their risk tolerance a bit by using CS, so that they can re-run the technical engineering analysis with a different perspective in mind.
BigInch, that is exactly the type of calculation I'd like to perform at some stage. I will obviously require some more detailed information from the client to do that, however at this stage I am just going for an order of magnitude calculation. The other part of the work I am doing is to present to the client some examples of where other companies have made similar risk tradeoffs.
Thanks again for the responses so far. I will keep researching and post back here as I learn more information from the client.
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
you must get smarter than the software you're using.
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
How lucky do you feel?
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
I know that there are different types of CRAs, but roughly how much more would it cost upfront (say, per kilometer of pipeline), relatively, to use CRA lining than just carbon steel? Would it be 2-3 times more expensive, or would it be closer to 10 times more expensive? Is it possible to get a feel for the order of magnitude comparison with minimal detail?
To get a very high-level order of magnitude understanding of how long a carbon steel pipeline would last compared to one with CRA lining, what would be the most important factors? Temperature, pressure and CO2 content? Again, I am just looking for a very rough estimate (i.e. would carbon steel need to be replaced every 5 years, or is it 20 years? etc.)
Coming from an engineering background myself, I know how frustrating and detail-insufficient my questions are - management consulting is a whole different game :) The information I am trying to gather is not for the purpose of performing any final economic analysis, but simply for my team's understanding of the order of magnitude differences between carbon steel and a corrosion resistant alternative.
I do appreciate your continued input!
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
1. The manufacturing process for CRA lined pipe is: a) buy carbon steel pipe; b) buy CRA pipe of smaller diameter and probably 3 mm wall thickness but could be less (based on end user's risk perception!); c) insert CRA pipe inside carbon steel pipe; d) expand CRA pipe plastically and carbon steel elastically so that carbon steel springs back and grips CRA pipe; e) perform NDT. Remember: your carbon steel pipe now does not need a corrosion allowance, so you will have saved some carbon steel.
2. How much corrosion allowance would the carbon steel pipe have required? Good question - were you just going to leave it to rot, or were you going to deploy some other form of corrosion control? OK start with working out how corrosive is the transported fluid towards the unprotected carbon steel. Oh dear, there are at least 15 corrosion models I can choose from - which one will give me the "right" answer (the answer is - none of them, but some could be closer than others, but how would I know. Go with the one that has the fancy name - it must be good, maybe the one that costs 50,000 bucks is the best). Finally, you decide to go with the free one off the web with a nice looking GUI (so it must be good right?!!)
http://www.standard.no/en/sectors/energi-og-klima/...
but wait, the fluid has H2S and this model doesn't deal with H2S
http://www.ife.no/en/publications/2009/matkor/pred...
Now what?
3. Hey this stuff is really corrosive, but that chemical sales rep that was here last week had this magic formula that would get the corrosion down to nothing and was so simple that "Bubba and Bubba only had to squirt a bit in now and again." Fantastic - we'll go with that so we can use carbon steel, half a micron corrosion allowance, and our top performing corrosion inhibition team. Don't need no fancy alloys round here - we got it all sorted and we feel lucky.
A bit of fun, but hopefully you see why you are aking the impossible on an internet forum
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
Internally Clad is somewhere in the 2 to 4 times as expensive as CS for material and installation, but you gain a bit from no corrosion allowance and over the long term no corrosion inhibitor. Overall costs if you look at an entire system are much less, i.e. it costs the same amount of money to dig a trench for a C Stl line as it does for a clad line, etc.
However a recent case I was involved in was where some bright spark (maybe even a management consultant...) decided to "use up" the corrosion allowance he had calculated without inhibitor and save himself some OPEX costs. Sadly real pipe doesn't behave this way and the result before the CA was "used up" was a series of leaks.
Also bear in mind that replacement costs tend to come out of OPEX and if the well / filed is nearing the end of its life, this may not be economic, e.g. why spend $10MM replacing your flowlines when there is only $5MM of profit left in the place once you remove all the taxes and royalties etc. If you had just spent a little more in the first place this wouldn't be a concern and you could continue to produce as long as it was possible. Wells and fields often change with time and especially with injection can turn sour during field life. Do you want to change the system later on?
My points are that there anre many issues to consider when an operator is thinking about what types of pipe to use and thinking ahead to when flows and money are less, investing p front actually makes sense. They may occasionally over spec a system, but on balance, your excessive cost issue can seem to be a very short term solution.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
Getting pretty tired of your evasions. You want specific answers to non-specific questions. Doesn't work that way. Every question you ask requires some knowledge of the application, any answer above is framed around people jumping through hoops to make up the details you refuse to provide. My advice is either to provide the details or ask site management to delete the thread.
If you job is 8-inch or smaller, you can save a ton of money and get outstanding results from Reinforced Thermoplastic Pipe (RTP). It is corrosion resistant and rated to very high pressures (everyone has ANSI 600 capable, several manufacturers have an ANSI 900 version). Bigger than 8-inch, poly liners work very well in carbon steel for a fraction of the price of stainless.
David Simpson, PE
MuleShoe Engineering
Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
Carbon steel seamless - USD 1700 per tonne
Carbon steel SAWL - USD 1150 per tonne
Carbon steel SAWH - USD 1050 per tonne
Carbon steel HFW - USD 1150 per tonne
CRA lined (unspecified CRA) - USD 11,300 per tonne or USD 700 per metre
CRA clad (unspecified CRA) - USD 12,700 per tonne
I can't vouch for these numbers, particularly the parity between HFW and SAWL, but it's better than nothing.
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys
- Galvanized pipes which are not that expensive
- Plastic pipes suitable for your fluid
- Carbon steel with thick wall to be good for x years
RE: Pipeline Material Selection - Carbon Steel vs. Corrosion Resistant Alloys